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HandlingMachining

AssemblyControl

PneumaticsElectronicsMechanicsSensoricsSoftware

ChineseEnglishFrenchGermanRussianSpanish

Blue Digeston Automation

053 789

HesseRationalization

of Small workpiecefeeding

Handling

English

BlueDigest

Hesse

RationalizationofSmallworkpiecefeeding

M

M

Orienting, sorting, checking and feeding


2/55

Hesse

Rationalization

with handling technology


3/55

Rationalizationwith Handling Technology

Blue Digest

on Automation

Handling

Pneumatics

Stefan Hesse


4/55


5/55


6/55

Table of contents

Foreword 5

Table of contents 7

1 Functions and objects 11

2 Bin feed devices 16

3 Stack devices 21

4 Magazines 24

5 Sorting devices 33

6 Metering and dosing 47

7 Clamping 56

8 Output, alignment, branching 58

9 Feed devices 62

10 Handling systems 85

11 Grippers 95

12 Sensors 99

13 Further reading and list of sources 101

14 Glossary of technical terms 103

99


7/55

1 Functions and objects

How can handling functions be represented?

Symbols are used to compile function charts. It is possible to specify only the

characteristics functions of a sequence or also all installed functions,

if appropriate broken down to elementary functions [3].

Composition of functions

1 = n 20

6 = 36 + 4

7 = 6 + 18

8 = 18 + 4 + 18

9 = 18 + 5 + 18

1 0 = 2 6 + 8

12 = 11 + 13

14 = 32 + 11

15 = 31 + 13

1 6 = 1 4 + 15

16 = 32 + 8 + 17 + 19

17 = 20 + 18

18 = 13 + 11

11

37 38 39 40 41 42

31 32 33 34 35 36

25 26 27 28 29 30

19 20 21 22 23 24

13 14 15 16 17 18

7 8 9 10 11 12

1 2 3 4 5 6

1

Functions and objects

Symbols for functions

1 Orderly storage

2 Partly orderly storage

3 Random storage

4 Division

5 Combination

6 Division and metering

7 Metered outfeed

8 Branching

9 Amalgamation

10 Sorting

11 Turning

12 Swiveling

13 Shifting14 Orientation

15 Positioning

16 Orientation

17 Guiding

18 Forwarding

19 Conveying

20 Stopping

21 Releasing

22 Clamping

23 Unclamping

24 Checking

25 Checking presence

26 Checking identity27 Checking shape

28 Checking size

29 Checking color

30 Checking weight

31 Checking position

32 Checking orientation

33 Measuring

34 Measuring position

35 Measuring orientation

36 Counting

37 Handling

38 Monitoring

39 Production40 Shaping

41 Changing shape

42 Joining


8/55


What typical behavior groups can be specified for round-section workpieces?

Depending on its geometrical shape, size (mass), material and surface pro-

perties, every workpiece has certain rest and motion behavior and a certain

stacking capacity. This is shown by examples of axially-symmetrical workpieces.

These properties have an influence on the design of handling devices.

13

Behavior groups,

shown by the example

of round-section

workpieces

Free rest positions

Guided motion positions

(rolling)

Guided motion positions

(sliding)

Creation of workpiece groups

(axially parallel)

Creation of workpiece groups

(coaxial)

Random order

How can we distinguish between workpieces?

Workpieces can be classified on the basis of numerous criteria. The classification

below is based on types of behavior. Classification of workpieces is particularly

important in order to allow selection of suitable function devices for handling

operations [4].

No. Type of behavior Examples

1 Complex workpieces

2 Flat workpieces

3 Cylindrical

workpieces

4 Block-shaped

workpieces

5 Conical workpieces

6 Pyramid-shaped

workpieces

7 Mushroom-shaped

workpieces

8 Hollow workpieces

9 Built-up shaped

workpieces

10 Irregular solid

workpieces

11 Spherical

workpieces

12 Bulk-length

workpieces

1 Functions and objects12

Distinguishing between

objects on the basis of

types of behavior.

Complex workpieces are some-

times referred to as hay-stack workpieces, since they

can tangle to form random

combinations.

Types of behavior can be furt-

her classified, for example on

the basis of dimensional

ratios.

W ~ H ~ L

W ~ H ~ L

W ~ H ~ L

W ~ H

L/D 0.5

L/D 0.5

L/D 1

L/D ~ 1

L/D 2

L/D 2

L/D > 1 L/D < 1 L1, L2, D1, D2


9/55


How can we influence frictional behavior?

The frictional behavior of workpieces is an important factor in situations where

these workpieces are able to move freely and depends principally on the

relevant coefficient of friction. Experiments will generally be required in order to

identify this behavior. Frictional behavior can be influenced to a large degree by

changing frictional pairings, for example by using air cushions.

15

Sliding on an inclined plane

e Constant (2.718)

g Gravitational acceleration

h Height of fall

v Velocity at radius end R

R Path radius

a Path angle

w Radius angular pitch

l Coefficient of friction

Sliding on air-cushion trough

1 Compressed air supply

2 Air nozzle

3 Air fi lm

p Pressure

t Time

l Coefficient of (air) friction

~ 104

G Dynamic frictional force

F Weight force

F = m g

H Static frictional force

a 1 ... 3

m Ma ss

g Gravitational acceleration

s Gap

Is it possible to handle flexible workpieces?

The increased use today of innovative workpieces such as technical textiles,

plastic sheeting, etc. means more hard-to-handle workpieces with unstable

shapes. Experiments will generally be required to find a suitable handling

method. Possible gripping methods include pairings of shapes, forces and mate-

rials. Force fields are generally the only option for large workpieces [5] to [7].

Handling methods

Suction cups with widely-distributed suction openings

Needle grippers with micro-needle arrays

Combinations of suction cups and aerodynamic paradoxes

Layer or drop of adhesive on gripper component

Gripping by freezing to refrigerated sheets

Electrostatic gripping

Oversize flat or shaped gripper jaws

1 Functions and objects14

Workpieces with

unstable shapes

Examples

1 Flat complex shapes (2D)

2 2 1/2-D cut shapes

3 Bellows, sleeves

4 3D shaped workpieces

5 Strips, belts, cables

6 Foil cut shapes

7 3D tubes/hoses

8 Tubes/hoses with end

reinforcements

Notes

Avoid 3D shaping of rubber

moldings if possible

Create easy-to-handle ends

(easy to grip and join)

Create broad gripping areas

to ensure low gripping

pressure

Produce cut shapeslocally from roll material

if possible

Allow for folds in the design

of gripper components

Edge reinforcements are

always an advantage, as

are beads and mirror

images

Moldings can be made

temporarily more rigid bycooling

1 2

3 4

7 8

5 6

h L

R

HG

1

3

F

F F

P

st

2

1


10/55

2 Bin feed devices

What is the best design for scoop segments?

The scoop segment of a scoop bin must be designed to match the workpiece

concerned. In the case of troughs, it must be ensured that dirt and chips can be

discharged automatically, for example through side slots.

l1 = l + 1l2 = d + 1

l1 = RR = (0.60.7) d

l1 = 0.5 dl2 = b + 1

l1 = (0.51.0) l

l2 = d + (12)

l3 = d1 + (23)

l1 = l + (12)

l2 = b + 1

l1 = l (12)

l1 = d1 + (12)l2 = d + (12)

l1 = l 0.6 = + 2

l1 = 1.1 dl2 = 0.1 d

0 3045

17

Scoop segment design

(dimensions in mm)

Some design tips:

Segments should be made

of wear-resistant material;

surfaces should be hard-

chrome-plated if necessary

Discharge openings should

be provided for dirt

Avoid V-slot abrasion with

conical workpieces

Protect segments against

overload (adhering residues)

Can workpieces be sorted in a bin?

In handling systems, bins are generally equipped with sorting or removal

devices. The workpieces are aligned by the alignment edges of the removal

devices. Scoop bins are particularly suitable for smaller workpieces.

2 Bin feed devices16

2

Bin feed devices

Scoop bins

n Double strokes per minute

p Occupation coefficient (0.5

to 0.7), depends on filling

level of bin

B1 = (8 ... 10 L)

B2 = (12 ... 15 L)

L Workpiece length

L1 = (7 ... 10 L)

L1 Scoop component length

v Sliding velocity to desti-

nation point in m/min.

z Number of scoop compo-

nents 20 ... 45

Delivery capacity

Q = n L1 p z/L

in units/min.

Drive rating

N = 0.008 L1

in kW

n = v/L1 p)

in double strokes/min.

L1

B1 B2


11/55

What is a stack bin?

Stack bins contain workpieces which have degree of freedom 2 with regard to

their position. For orderly feed to take place, they must be brought or sorted into

a line. The appropriate motion can be executed either continuously or intermit-

tently. Additional vibrators are generally also required in order to break up any

bridge accumulations.

19

Stack bins

Sliding and rotary bins

1 Slide path

2 Vibrator

3 Rotary disc

4 Workpiece

Angle of inclination

Friction bin

1 Bin

2 Roller, eccentrically-

pivoted

3 Conveyor belt

4 Rocker arm

= 4 ... 6

Pipe feed bin

1 Bin

2 Stand

3 Drive shaft with overload

coupling

4 Rotary metering device

5 Outlet

6 Flat to create vibrator

effect

What may causes problems with scoop segment bins?

Problem areas are the points of transfer from the bin to the scoop segment and

from this to the output channel. In the first case, scraping and abrasion of

stationary workpieces against the segment may lead to malfunctions, as may

also result if several workpieces jam against the bin wall if half the bin width

is 4x the length of the workpieces. There must be no collisions or jamming

during output [8].

18

1

23 4

5

6

7

8

8

Scoop segment bins

1 Rodless pneumatic

cylinder

2 Bin

3 Thrust rod

4 Sensor to detect ring slot

5 Output wheel for incorrect-

ly-oriented workpieces

6 Thrust output for correctly-

oriented workpieces

7 Solenoid actuator to index

wheel 5

8 Workpiece (example)

Possible sources of faults

in segment design

Wrong

Tilting and jamming at the out-

let must be avoided.

Right

Spring-loaded components,

sliding radii and push ejectors

for sideways workpieces

2 Bin feed devices2 Bin feed devices

2 3

3

3

5

6

4

4

4

1

1

1

2

2

2


12/55

3 Stack devices

Can a stack be created and broken up by using the same principle

in two different directions?

The main problem with buffer concepts is integration. The way a buffer is filled is

just as important as the way it is emptied. One suitable automation solution is

to use steel-strip or fabric-belt troughs to create sack buffers.

21

3

Stack devices

Buffer system with steel-stripor fabric-belt trough

a) Loading station

b) Loading; the buffer volume

is continuously adjusted

during filling to match the

filling level

c) Loading completed

d) Pallet removed; transport

can now be carried out

e) Unloading station with

filled pallet

f) Break-up of stack by step-wise shortening of trough

strip

1 Feed zone

2 Strip roll

3 Frame

4 Steel strip, chain, belt,

cable

5 Pal let

6 Outlet zone

7 Workpieces (pipes, shafts,

rods, posts)

8 Metering device

Are multiple arrays of scoop segments advantageous?

The principle of a scoop segment can be produced in a variety of designs,

with both linear and arc motions, and in single and multiple configurations. The

solution shown below is used to separate workpieces out of a bin and provide

pre-orientation, or if required also full orientation. Further orientation devices

can be used downstream.

2 Bin feed devices20

Lifting-plate bins

1 Outlet conveyor zone

2 Linear vibrator

3 Scoop segment

4 Return path

5 Bin

6 Base frame

7 Orientation zone

8 Overhead transfer from

top conveyor zone to

orientation zone

W, L Main dimensions of scoop

segment, matched to work-

piece class

Motion phases of segments

Workpiece classes

Dimensions rangeMass in kg

Throughput in units/min.

1050 mm 50100 mm 100300 mm 0.05 0.2 2

1120 160 130

3

4

5

96

2

18

7

3

21

a b

4

c d

8

e f

5

6 7


13/55

How can workpiece stacks be broken up?

Long workpieces such as pipes, rods, boards and tree-trunks are often fed in

bundles. The bundles are then broken up by feeding the workpieces stepwise

into a line configuration. When breaking up stacks of sheet-metal workpieces, it

is advantageous to use an intermediate setdown position in order to allow large

distances to be bridged.

3 Stack devices

How can small flat workpieces be stacked?

Small flat workpieces can be stacked, for example as a preparation for packing,

by using conveyor belts running at different speeds. The workpieces need to be

stood on edge as they pass from one belt to the other. Stacking rollers and

wheels can be used for this purpose.

23

Example 4:Stacking roller

Variant 1

1 Conveyor belt

2 Stacking wheels at left and

right of conveyor belt

3 Setdown rail

4 Conveyor belt

5 Workpiece stack

Variant 2

1 Sliding track

2 Segmented roller

3 Setdown zone

4 Workpiece

5 Workpiece stack

Example 5:

Stacking with stacking roller

1 Infeed belt

2 Metering device

3 Stacking roller

4 Vibrator conveyor

5 Outfeed belt

Example 6:

Stacking with rotary brush

1 Infeed belt

2 Sliding track

3 Rotary brush

4 Outfeed belt

5 Workpiece stack

V2 V1

3 Stack devices22

Example 1:

Phases of operation of a stack

trough

1 Workpiece holder

2 Support

3 Pneumatic cylinder

4 Pivot arm

5 Workpieces

6 Lowering unit

7 Rolling track

8 Metering device

9 Tapered rollerA Lowering of workpiece

holder

B Opening of pivot arm

Example 2:

Swivel-plate device

1 Workpiece outfeed

2 Outfeed track

3 Lifting segment

4 Fixed track

5 Separator

6 Rolling track

7 Divider/metering device

8 Workpiece

9 Swivel plate

10 Workpiece feed

11 Hydraulic cylinder

Example 3:

Destacking device for sheet-

metal workpieces

1 Intermediate setdown

position

2 Suction cup

3 Spreader magnet

4 Lifting unit

5 Arm guide

6 Frame

7 Ejector finger

8 Reserve stack

9 Supply trolley

10 Sub-frame

2

6

3

1

4

5 78

9

A B

1

7 2 3 5 8

46 6

9

1

32 5 8 6 4 7 9 210

11

1 5

2 3 4

4

4

32

1

V1

V2

12 3

4

V1

V2

1

2

3

4

V1

V2

5

5


14/55

4 Magazines

What is the best design for the workpieces outlets of stack magazines?

These should be designed so as to avoid the risk of bridge formation, which can

seriously impede the flow of workpieces. Moving components are thus fitted

which interfere with the formation of workpiece arches. These components may

be pivoted levers or lugs and rotary devices. If possible, bin walls should be

straight and not inclined, and smooth rather than rough.

Stack magazine 2

1 Multiple swivel metering

device and pivoted lever

2 Pair of pivoted levers

3 Two-channel outlet and

clockwise/counterclock-

wise rotor

4 Sickle metering device

with modified outlet shape

5 Straight-walled bin and

toggle lever

6 Counter-rotating brush

Note

Design measures should be

taken to absorb the weight

forces of upper layers of work-

pieces.

S Poor

G Go od, better

25

1 2

3 4

5 6

S

G

4

Magazines

Stack magazine 1

1 Magazine wall

2 Ratchet

3 Drive rod for ratchet

4 Drive shaft

5 Metering drum

6 Workpiece

7 Gravity shaft

Tool to aid rapid filling

of magazine

Avoidance of bridge formation

1 Air-pressurized rubber

diaphragm

2 Air injection point (L)

How can workpieces be removed from stack magazines?

One frequently-used solution is indexed drums. Workpieces are output by being

tipped into a channel. The indexing motion is generally provided by a control

cam and lifter rod. It is important that the actuating stroke should be produced

by spring force (to provide overload protection), with a direct linkage only for the

return stroke.

Output with slide metering device

In the case of solution A, the upper side of the slide is ridged to generate motion

in the workpieces and thus prevent the formation of bridges. In the case of sol-

ution B, the gripper arm is fed with a workpiece for further handling (machine

feed).

4 Magazines24

1

2

3

4

5

6

7

A

4

5

6

7

A

A B

1

2

L


15/55


16/55

4 Magazines

When do we need special components to ensure a defined position and orien-

tation?

In general, we can say that with V-shaped workpieces we can always do without

orientation aids, with axially symmetrical workpieces very often, particularly in

devices used to feed machines. In automated assembly systems, on the other

hand, it is often necessary for functional reasons to maintain a certain orien-

tation, for example when meshing gear wheels (example 11). The examplesbelow maintain position only:

29

1 2

3

4

2

1 2 3

4 5 6

Example 2:

Holder for straight-cut spur

gears

1 Positioning mandrel

2 Bar to prevent rotation

3 Workpiece

4 Pallet base

The feather-key slot of gear-wheels can also often be used

to prevent rotation. The most

suitable type of workpiece

holder will also depend on the

type of gripper to be used.

Example 3:

Holder for round workpieces

1 Compact inclined holder

2 Plug-in holder with drawn

collar

3 Plug-in holder with

pressed raised edge

4 Pallet base with support

plate and template

5 Plug-in holder with turned-

up raised edge

6 V strips for wave-shapedworkpieces

What is the best design for rolling channels and sliding tracks?

Many methods can be used to magazine and forward individual workpieces,

pipes, bars and profiles. It is often possible to create channels using only a small

number of standard components. The track width can easily be adapted, for

example for bends, using spacer sleeves and washers.

4 Magazines28

Example 1:Rolling channels, sliding

and roller tracks

1 Workpiece

2 Long material

3 Electronic components for

SMT systems

4 Trough

5 Ro ller

6 Wire

7 Circuitry

Important:

Provide space to accommo-

date dirt deposits.

Spring steel is a good

material for rolling channels

and adapts well to bends

(provide elongated mounting

holes instead of round

ones).

Straight-cut gear wheels will

not roll if they are in contact

with each other.

V trough

b Half V angle

b = 45 for light workpieces

b = 60 for light workpieces

B = 0.8 D

U trough

H = 0.33 D (sphere)

H = 0.27 D (cylinder)

H = 0.5 D (r ing)

d Wor kpi ece d iame te r

H Edge height

1

1

1

7

4

6

5

6

1 2

DB

H

3 5


17/55

4 Magazines

How do lifting magazines work?

In the case of lifting magazines, workpieces are removed from the top. This type

of magazine is thus very suitable for workpieces with sensitive surfaces which

cannot be slid, for example workpieces with polished, coated or galvanized sur-

faces. The lifting function is provided by similar mechanisms to those used in

drum magazines.

31

Example 7: Lifting magazine

1 Workpiece

2 Light barrier

3 Magazine shaft

4 Rotary plate

5 Drive motor

6 Lifting device

7 Gear rack

8 Re lay

D Reference circle diameter,

e.g. 150, 200 or 260 mm

Drive systems for lifting

devices

Indirect drive

1 Ratchet mechanism

2 Spindle/nut transmission

3 Rack-and-pinion trans-

mission4 Friction-wheel trans-

mission

5 Gravity drive

Direct drive

6 Lifting spring drive

7 Pneumatic or hydraulic

cylinder

8 Rodless cylinder

9 Linear electric motor

When do we need special magazines?

Special magazines are used to provide particular handling functions or meet

certain process conditions. This type of magazine is generally not available off

the shelf.

4 Magazines30

Example 4:

Shaft magazine with auxiliary

rail for non-stackable work-

pieces

1 Magazine shaft

2 Auxiliary rail

3 Metering slide

4 Workpiece

Example 5:

Disc magazines

1 Input side

2 Removal side

3 Workpiece

Inclined-axis magazines have

the advantage that stored

workpieces move to the edge

of the magazine by gravity,

Example 6:

Magazine plate feed device

1 Feed arm

2 Pivoted guide rail3 Plate

4 Workpiece

5 Edge

6 Vibrator chute

1

4

2 3

1 12 23 3

1 123

2

6

1

4

2

3

5

2

3

4

5

D

3

1

6

7 6

2

8

5

1 2 3 4 5

6 7 8 9


18/55

5 Sorting devices

Should we also carry out orientation operations within a magazine?

It is often easier to fill a magazine with only partly sorted workpieces, particu-

larly when these are filled by hand, and then eliminate the remaining undesired

degree of freedom within the magazine. This can be carried out in free fall

at turning points, or swivel turning devices can be used. In either case, signal

processing and a controller are not required [10].

33

1

2

3

4

6

5

6

7

2

a b

1

2 3

64

5

1

2

3

4

56

a b

5

Sorting devices

Sorting shouldered sleeves

in a step magazine

1 Workpiece

2 Step magazine

3 Metering device

4 Sorting channel

5 Metering slide

6 Helix guide slot

7 Correctly oriented

workpiece

Sorting cups in a shaft

magazine

1 Magazine shaft

2 Metering device

3 Workpiece

4 Carrier pin, operativeif opening first

5 Fall-through opening

6 Swivel segment

a Operation in the case

of incorrect orientation

b Operation in the case

of correct orientation

Sorting collared workpieces

1 Feed channel

2 Rotatable but non-driven

core piece

3 Rotating outer ring

with drop-in opening

4 Workpiece

5 Output channel

a Operation in the case

of incorrect orientation

b Operation in the case

of correct orientation

How do climbing magazines work?

Climbing magazines are shaft magazines equipped with lifting pistons which

advance in a stepwise manner. The lifting pistons are self-locking and can be

released to allow filling of the magazines. They can be driven economically by

compressed-air pulses. The workpieces are always removed from the top of the

magazines [9].

4 Magazines32

Example 8:

Climbing magazines

1 Workpiece stack

2 Magazine shaft

3 Bayonet lock

4 Lifting piston

5 Air supply

6 Lifting-piston seal

7 Pressure pin

8 Pressure plate to transmit

a load-dependent force

to the internal pressure

medium

9 Pressure-medium reservoir

10 Light barrier

Comparison of magazines

Good

Limited suitability

Poor

Examples of parallel oper-

ation of climbing components

1 - 3 Guide rod

4 Workpiece

5 Magazine rod

6 Lifting mechanism

7 Support plate

Type of magazine

Interchangeability

Convertability

Automatic fillingcapability

Gravity shaft Lif tingmagazine

Lifting piston Climber

10

10

6

2

1

4

3

5

5

1

6

6

2

148

6

7

9

2

5

5

67

4


19/55

5 Sorting devices

How can guidance and correctly-oriented buffering be combined?

Ducts and channels can be used to link various workstations. The workpieces

can be fed along these links either singly or in groups. Flat workpieces can

generally be transferred using this method only in a continuous workpiece

stream [13].

35

Example 1:Orientated forwarding from

a press

1 Press tool

2 Material strip

3 Guide channel

4 Level monitoring

Example 2:

Orientated forwarding

to a flat pallet

1 Workpiece in working

position

2 Rotary disc

3 Compressed-air nozzle

4 Guide channel

5 Flat pallet

Example 3:Orientated output to a press

1 Cutting tool

2 Rotary disc

3 Magazine rail

4 Rail mounting

5 Workpiece

6 Compressed air

Example 4:Orientated output from

a stamping tool

1 Stamping tool

2 Rotary disc

3 Magazine bar

4 Rail mounting

5 Compressed air

6 Workpiece

What principle can be used to sort transformer core stampings?

If it is not possible to magazine stampings directly from the stamping tool, they

must be sorted from a random accumulation. In many cases, step-by-step

sorting will be advantageous or necessary. A sorting drum is first used to

produce a string of single workpieces. The remaining degrees of freedom are

then eliminated.

5 Sorting devices34

45

6

7

S

2

1

3

S

Sorting drums

The workpieces are aligned by

bead rings. Workpieces which

have been aligned exit from

the drum via slots in the drum

shell.

Separating unequal-leg

stampings

On the vibrator unit 7, the

workpieces 4 are alignedaccording to their longer legs

and thus pass from the rail 5

to the magazine rail 6.

S Vibrations

Suspension

M-shaped stampings suspend

themselves when they pass

over the tilting edge 2 and

reach the rails 3.

The four possible orientations

of L-shaped stampings

1

2

3

4

4

1

2 3

1

2

6

3

5

5

44

41

2

5

3

6


20/55

How can we describe the logical relationships involved in sorting with rotary

and inverting devices?

In order to determine the control functions required with a sorting device, we

must study the logic relating to the rotation and inversion of workpieces present

in random order. The example below assumes 4 possible positions. We first com-

pile a function table with yes/no information (1/0). Workpieces which do not

conform to any one of the 4 signal patterns will be declared as defective. Theswitching functions for inversion about x (Wx), inversion about z (Wz) and ex-

clusion (F) are then simplified with the aid of Karnaugh diagrams. Finally, the

signal circuit diagram is drawn [11].

Signal circuit diagram

S1S2S3

WxWzF

1

&

&

&

&

&

S3 S2 S1 Wx Wz F

0 0 0 0 1 0 Position 2

0 0 1 1 1 0 Position 3

0 1 0 0 0 1 Wrong

0 1 1 1 0 0 Position 4

1 0 0 0 0 1 Wrong

1 0 1 0 0 0 Position 1

1 1 0 0 0 1 Wrong

1 1 1 0 0 1 Wrong

Function table

5 Sorting devices 37

1

0

1

Position 1

Y

Z

X

A

Position 3

1

0

0

S2 S1

Wz

Wx

0

0

0

Position 2

Position 4

1

1

0

1

2

3

Wx

Wz

Detecting shape with spot

sensors

A Stop

S1 to S3 Sensors

W Inversion

Karnaugh diagram

This is a graphical method of

simplifying logical switching

functions with several vari-

ables to find the shortest form.

What workpiece features can be utilized for sorting ?

The features of a workpiece and the selection of technical equipment for sorting

are closely related. We will always attempt to utilize the features which can

assure maximum reliability of the sorting process. The resulting solutions can

often be surprisingly simple, as the example of air-jet sorting shows.

5 Sorting devices36

D

DD

D

D

D

1

2

3

4

S

Y Z

XWerkstck

(Soll-Lage)

S1

S1

S2

S2

S2

S1

Wx= S1 ^ S3

S3

S3

S3

Wz = S3 ^ S2

F = (S2 ^ S3) v (S3 ^ S1) v(S2 ^ S1)

Sorting with air jets

Two air jets ensure that in-

coming workpieces are sorted

into two channels according

to their orientation.

D Compressed air

Sorting pins

A recirculating double wedge

slide picks up randomly-

ordered workpieces and

transports these to an output

point.

Sorting with a video system

One workpiece at a time oc-

cupies the lowest position in a

parabolic trough. The rotary

motion is then halted precisely

when the desired orientation

is reached.

1 Camera

2 Monitored area

3 Drive motor

4 Support structure

with vibrator

S Vibration

Desired

position

Workpiece


21/55

What workpiece features should be exploited for sorting?What conveyor components can be used to aid mechanical sorting


22/55

5 Sorting devices

What workpiece features should be exploited for sorting?

Every object has a wealth of features. For the purposes of sorting, we select

the features which can be used to obtain a reliable result at minimum cost.

Mechanical methods are usually cheap but inflexible. The greater the number

of free workpiece motions involved, the more unreliable the sorting operation

generally becomes. The answer in most cases is to provide more results

monitoring.

41

1 A 2 B 3 4 5

6

A B

2

7 8

6

A A B B

I II III IV

1

25

4

3

5

4

2

5

4

2

Sorting using profile openings

1 Vibrator chute

2 Wi per

3 Returned incorrectly-

oriented workpieces

4 Vibratory motion

5 Correctly-oriented work-

piece

6 Return track for incorrect-


7 Ejected workpiece

8 Profile openings for incor-

rectly-oriented workpieces

(3 windows in succession)

Angle (approx. 70)

Sorting in a shaped trough

This exploits the effect of the

center of gravity. The work-

pieces gradually assume the

correct position. Figs. I to IV

show the orientation

sequence.

Sorting using a catch hook

Incorrectly-oriented work-

pieces are impaled and rotate.

1 Correctly-oriented work-

piece

2 Incorrectly-oriented work-

piece

3 Discharge channel

4 Vibrator device

5 Catch hook

What conveyor components can be used to aid mechanical sorting

in a vibrating conveyor?

Although there are only a few basic workpiece shapes, there are many different

variants, for which the solutions are often surprisingly simple. Most variants will

admittedly require refinement during the experimental stage before they work

perfectly, but once this is done the resulting sorting mechanism is in most cases

uncomplicated.

5 Sorting devices40

A

12

34

5

C

1

2

1

B

1

2

3

D

1

2

3

E 1 2 3 4

Sorting with shaped

devices

A Toggle lever

A toggle lever 2 oscillates

along with the main system.

If its motion is restricted as a

workpiece 3 passes through

on the helix 4, this causes a

change in the reaction of the

ejector lever 5.

1 Transmission lever

B Tilting edge

1 Helicoidal vibrator

2 Workpiece in good

position

3 Workpieces in bad

position tilt over

C Suspension rail

1 Workpiece in good

position is suspended


D Aligning post

1 Tube with profile opening

in infeed

2 Post edge, operative only

with incorrectly-aligned

workpiece

3 Aligned workpiece4 Vibrator attachment

E Aligning post

1 Workpiece shapes

2 Tilting zone in helicoidal

vibrator

3 Post edge

4 Aligned workpiece

How can a fuse-holder be sorted in a vibrator?How can chicanes be designed to provide a sorting function within vibrators?


23/55

Example 1:

Workpiece

1 Inclined helix

2 Lower part of helix

3 Retainer

4 Hanging ledge

5 Sorted workpiece

6 Magazine exit

7 Workpiece

Roughly 20% of conveyed

components exit from the

vibrator in a sorted state.

Handling technology

5 Sorting devices

How can a fuse-holder be sorted in a vibrator?

A facility is provided for workpieces to hang in a slot 0.5 mm wide. Workpieces

which fail to do this fall back into the bin. The workpieces are then picked up by

a hanging ledge, followed by transfer to a slot magazine.

43

1 2 3 4 5

4

6C

C

B

B

A A

1

2

3

47

6

Section A A Section B B Section C C

0.4 mm

Deflector

Notch

Slot

Hanging ledge

Slot magazine

Incorrectly-orientedworkpieces

How can chicanes be designed to provide a sorting function within vibrators?

There are many ways of using workpiece features for sorting by making work-

pieces tilt, fall or align themselves. The example shows an unusual way of

sorting open rings [12]. The workpieces pass from the flat track into a trough and

are then impaled on a mandrel. Some of the rings rotate on the mandrel about

their own axis until the annular gap in the rings lines up with the web plate.

5 Sorting devices42

1

2

3

1

23

5

4 1 3

D

1

2

3

E

32

1

1

2

Sorting in a vibrator

A Standing cylinders on end

1 Workpiece

2 Edge to produce tipping

against the outer wall


B Sorting right-angle work-

pieces with unequal-length

sides

1 Workpiece

2 Retaining bracket3 Inclined inversion track

with aperture

C Sorting open circlips

1 Magazining mandrel

2 Trough exit

3 Web plate

4 Vibrator5 Workpiece

D Sorting right-angle work-

pieces with equal-length

sides

1 Helicoidal vibrator bin

2 Helicoidal zone produced

by milling

3 Workpiece

E Sorting tapered control

knobs

1 Helicoidal vibrator bin

2 Sliding path matched

to workpiece

3 Correctly-oriented

workpiece

What sorting components can be used with small surface features?How can a suspendable workpiece be sorted?


24/55

Example 3:

Workpiece

1 Notc h

2 Workpiece

3 Guide slot to allow exit of

incorrectly-oriented work-

pieces

4 Inclined support surface

5 Curved guide to achieve

stud-first orientation

6 Covered slide track

7 Vertical wiper

8 Cover plate

9 Stop edge for stud

Handling technology

Example 2:

Workpiece

1 Lateral slot to allow exit of

workpieces with incorrect

bushing orientation

2 Ramp to stand workpieces

on edge

3 Flange

4 Slot

Handling technology

5 Sorting devices

What sorting components can be used with small surface features?

For the stamping shown below and similar workpieces, guide edges can be pro-

vided against which lugs, projections, hooks, etc. can align themselves.

Incorrectly-oriented workpieces must then be removed via a separate guide

track in order to obtain uniform orientation at the exit.

45

4

3

5

B

B C

C

6

A A

2

1 7

2

3

8

9

6


Deflector

Notch

Guide slot

Suspendedworkpieces

Curvedguide

Guidance

How can a suspendable workpiece be sorted?

The success of the sorting operation depends on two factors the workpiece

reaching a state of lying on its back, and the subsequent longitudinal orien-

tation. Following this, there are two possible orientations bushing at the front,

or bushing at the rear. Uniform orientation is achieved as the workpieces are

suspended in a slot.

5 Sorting devices44

C

C

B

B

A

A

D


3 42

1

D

Deflector

Notch

Lateral slot

Ramp

Suspendedworkpieces

Incorrectly-orientedworkpieces

Does the motion sequence have an effect on the reliability of a meteringHow do we carry out sorting in scoop bins?


25/55

6 Metering and dosing

q y g

device?

The motion of a metering device (start and end) may comprise a step change,

may be jerky, jerk-free but non-linear or jerk-free and linear. We must decide on

the basis of the active forces what motion function can be accepted.

47

6

Metering and dosing

Motion sequences

with metering function

a Acceleration

s Distance

t Time

v Velo city

Examples

1 Brake motor

2 Switching cam

3 Drive crank

4 Shaft magazine

5 Workpiece

6 Metering slide

7 Metering chain8 Rotary metering device

with Archimedian screw

9 Rotary table with roller

crown

10 Swivel-segment metering

device

11 Roller metering device

Jerk at start Jerk-free but Motion jerk-freeand end non-linear motion and linear

y g p

A typical feature of this is that workpieces are drawn directly from a heaped con-

figuration. This can be achieved through linear or rotary motions of the active

components. The scoop components may be mandrels, troughs, cups or strips.

Scoop bins are particularly suitable for feeding small workpieces to automatic

machine tools.

5 Sorting devices46

Example 4:

Scoop bin

1 Bin

2 Workpiece

3 Discharge track

4 Scoop segment

5 Scoop mandrel

6 Release tube, relative

motion after ejection

position is reached

7 Shaft magazine

Example 5:

Scoop-wheel bin

1 Bin

2 Scoop wheel

3 Gravity shaft

4 Workpiece

4

1 2

1

3

7

2

6

5

1

2

3

4

s

t

s s

t t

v

t

v v

t t

a

8

t

a a

t t

1

10

44

4

55 9

112

4

5

4

8

4

7

6

2

3

Does the workpiece shape influence the design of the metering device?How should metering devices be designed for heavy or undercut workpieces?


26/55


Metering devices must often be specially matched to a particular workpiece and

pick-up direction. The illustrations below show two typical phases of a metering

operation.

49

Example 4:

Metering flat workpieces

1 Metering slide

2 Swivel segment

3 Slide for feed to machine

4 Workpiece

Example 5:

Metering of ball bearings

from a bar magazine, removal

from above by an industrial

robot

1 Spring-loaded segment

2 Workpiece stop plate

3 Workpiece

4 Spring cap

5 Spring

Example 6:

Metering of pipe fittings

(T pieces)

1 Spring-loaded detent

2 Housing

3 Drive yoke

4 Workpiece

5 Return stroke

6 Metering stroke

In the case of heavy workpieces, the workpiece to be metered should be freed of

the weight forces of the other workpieces in the magazine. This can be achieved

by using single-acting, double-acting, mechanically- or pneumatically-controlled

workpiece barriers. These not only relieve weight but provide stepwise release

of the next workpiece.

6 Metering and dosing48

Example 1:

Metering device with barrier

1 Magazine shaft

2 Barrier

3 Metering bar

4 Workpieces

Example 2:

Metering slide with double

barrier

1 Magazine shaft

2 Metering slide

3 Workpiece

4 Barrier in lock configur-

ation

5 Clamping point

Example 3:

Metering device for undercut

workpieces

1 Magazine shaft

2 Metering slide

3 Barrier


5 Gripper for workpiece

transfer

4

1

2

3

3

1

4

25

31

4

2

5

3

1

42

3

1

4

2

5

3

14

25 6

How can thin stampings, foils, metal and paper sheets and textilesWhat special points must be noted regarding distribution?


27/55


be separated?

Thin workpieces can be separated and metered by pairings of force, shape or

material. This is especially difficult with two-dimensional textile workpieces.

51

Separating thin stampings

1 Electrostatic2 Air suction

3 Velcro

4 Freezing

5 Needle grippers

6 Aerostatic paradox

7 Suction air and silk-paper

separator

8 Staggered setdown

and gripper

9 Push-off with ratcheted

roller

10 Roller pull-off

11 Air suction roller

12 Adhesive roller

13 Spring-loaded press-on

suction cup

14 Local cutting instead

of metering

15 Magnetic roller conveyor

In the case of the rotary distributor A, the driver compartment is designed to

provide a reliable pick-up function while ejecting excess workpieces. This is

carried out using compressed air while one workpiece at a time is held by

vacuum. Wherever possible, use should be made in distribution of the workpiece

shape, as shown in example B. Workpieces with an almost symmetrical center of

gravity tend to overturn when they impact on the distributor slide. A diagonaldistributor channel D avoids hard impacts [15].


B

1

2

A

123

4

567

C

3

1

2

v4

D

12

3

4

A Rotary metering device

1 Workpiece held in position

2 Compressed air channel

3 Suction air channel

4 Workpiece to be ejected

5 Magazined workpieces

6 Stack magazine

7 Rotor

B Slide metering device

1 Metering slide

2 Workpiece with shape

features

C Double metering device

1 Shaft magazine

2 Driver cam

3 Roller chain

4 Slide

v Metering speed = Chain

speed

D Inclined channel metering

device

1 Feed track

2 Metering slide with

diagonal channel

3 Workpiece which over-

turned during meteringand was then wrongly

machined

4 Correctly machined

workpiece

1 2 3

4 5 6

7 8 9

10 11 12

13 14 15

How can layers of paper be separated?

i

How can we assist the metering of thin flat materials?

i fl


28/55


Particularly in industrial bookbinding, there is a need to separate and compile

single and folded paper sheets. Some remarkable cycle times are achieved for

example, 250 to 350 workpieces per minute with rotary systems. The gripper

drums do not, however, rotate at a constant speed this is reduced at the

moment of gripping. The collector bins generally pass through numerous

metering units until a book block has been compiled [14].

53

A

1

2

78

3

4

5

6

3

4

9

1

2

10

8

B

3

4

5

1

2

6

10

9

1

2

7

4

5

6

98

10

Separating paper

layers

A Metering and assembly

using translatory components

1 Stack in magazine

2 Pivoted suction cup used

to separate bottom layer

from stack

3 Movable stack support

4 Tongs gripper

5 Monitoring of closing

operation (check for no

workpiece/double work-

piece)

6 Driver

7 Collector channel

8 Conveyor chain in collector

9 Gripper arm

10 Collector bin

B Metering and assembly

using rotary components

1 Stack in magazine

2 Pivoted suction cup

3 Movable stack support

4 Clamp gripper

5 No workpiece/double

workpiece monitoring

6 Gripper drum

7 Separator worm drive

8 Driver pin

9 Conveyor chain10 Collector channel

It is difficult to separate thin materials and workpieces, since these may stick

together. Separating can be improved by using various aids, for example by

blowing compressed air between the upper layers, by creating different pressure

zones, or generating repulsion forces with spreader magnets. Among the mech-

anical devices which can be used are precision exit apertures and stop edges.


12

3A

5

7

21

34

B

D

31

2

4

E

1

2

3

4

F

12

3

4

5

6

7

3

21

4

C

Separating flat

workpieces

A Separating thin plates

Air can be blown in by several

nozzles all round the work-

piece.

1 Suction cup

2 Air nozzle

3 Pallet lifting device

B Pneumatic separator

1 Gripper head

2 Flat textile

3 Compressed-air supply

4 Exiting air5 Impermeable table

6 Vacuum zone

7 Atmospheric pressure area

C Spreader magnets as

separator aid

1 Suction cup

2 Top floating workpiece

(ferrous sheet)

3 Spreader magnet

4 Stack of sheets

D Rotary brush asseparator aid

1 Rotary brush

2 Textile stack

3 Counterholder bar

4 Table surface

E Magazine and separator

for solder contacts

1 Magazine

2 Metering slide

3 Retainer

4 Workpiece

F Separating cards

1 Belt

2 Guide roller

3 Pressure roller

4 Knife edge as retainer

5 Card stack

6 Lifting device

7 Air suction

What physical variable is used as the basis for dosing?What are the problems associated with the separation of thin cut workpieces?

S ti thi t


29/55


Dosing is carried out on the basis of mass, volume or number of units [16].

Mass dosing takes the form of a direct comparison of mass on weighing devices,

volume dosing measures out a certain volume (mass = volume x density,

assuming that density is a constant), while unit dosing counts out a certain

number of units (mass = number of units x unit mass).

55

Example 1:

Mass metering

1 Bin

2 Screw conveyor

3 Stirrer

4 Switch-off device

5 Shut-off flap

Example 2:

Volumetric metering

1 Suction phase: Pistondosing device

2 Ejection phase

3 Drop piston

4 Level-controlled shut-off

Often, the only effective way to separate thin cut workpieces is by using friction;

the main problem is then to hold back the subsequent workpieces in a stack.

Highly-developed devices have been produced in this area for the automatic

feed of punched cards. These solutions can be used today for other purposes in

a similar or modified form.


1 2 3

5

4

6

A

3

5 7

B

Separating thin cut

workpieces

A Separating by friction

1 Driven roller for forwarding

2 Guide plate

3 Pull-off roller

4 Metering roller

5 Counterrotating wiper belt

6 Lifting magazine

7 Held-back second work-

piece

B Combination separation

1 Suction trough

2 Perforated conveyor belt

(permeable to suction air)

3 Suction air connection

4 Cam to pull off top work-

piece

5 Held-back workpiece

6 Lifting magazine

7 Retrodirective belt8 Suspension mounting

for retrodirective belt

1

3

2

4

3

2

5

1 2

3 4

How can we protect clamping points against the input of incorrect workpieces?

Avoidance of incorrect

What basic clamping methods are available?

7


30/55

7 Clamping

Incorrect or incorrectly-oriented workpieces may cause serious damage to a feed

or machining operation. Monitoring is therefore always advantageous. In many

cases, even simple technical means will be sufficient to prevent an incorrect

input. In all the examples below, salient points of the workpiece are sensed. If

the contour is incorrect, the device refuses to accept the workpiece in question.

Monitoring devices of this kind are particularly advisable when magazines are

filled manually.

57

B

1

2

3

D

1

2

3

3

1

2

C

1

3

2

1 2 3 3

A

Avoidance of incorrect-


in clamping devices

A Protection for a clamping

device


pieces cannot be inserted.

1 Clamping device

2 Spacer bracket

3 Workpiece

B Protection for a feed

channel

1 Workpiece

2 Uncontrolled sensor lever

which engages in the slot

in the workpiece

3 Sliding channel

C Protection for a rolling

channel

1 Workpiece

2 Sensor roller with mirror-

image profile of workpiece

3 Rolling channel

D Protection for magazine

input

An insertion template allows

only correctly-oriented work-

pieces to be inserted.

1 Magazine tube or shaft

2 Adjustable or fixed

contour-checking

component, template

3 Workpiece

Clamping is an operation which is of particular importance in jig construction. It

involves the temporary securing of a material object in a specified orientation

and position by the application of a clamping force by mechanical (springs), flui-

dic, electromechanical or electromagnetic means. Mechanical clamping grippers

incorporate a large number of lever transmission systems.

7 Clamping56

7

Clamping

Theoretical possibilities

1 V-jaw clamp

2 Pressure plate

3 Double clamp

4 Spring clamp

5 Clamp pin

6 Clamp lever

7 Clamping against fixed

corner

8 Centering action

9 Hold-down clamp

10 Clamping againstcentering jaw

11 Leaf-spring clamp

12 Permanent-magnet clamp

13 Spindle-driven jaws

14 Pneumatically-driven jaws

P Compressed air

M Permanent magnet

1 2 3

4 5 6

7 8 9

10 11 12

13 14

M

P

How can we split a workpiece flow?

Branching

What physical effects can be exploited during the output of workpieces

from clamping devices?8


31/55

8 Output, alignment, branching

Branching is required particularly when we wish to feed workpieces to parallel

coupled machines or store these in buffers. In most cases, workpieces are

required to arrive singly and must thus be separated beforehand. The technical

means used to achieve this are controlled deflectors and multiple metering

devices.

59

Branching

Example 1:

Track multiplier

1 Feed track

2 Pivoted lever


4 Workpiece

5 Output track

Example 2:

Deflector

1 Rolling track

2 Workpiece

3 Stop

4 Controlled deflector

5 Output track

Example 3:

Metering slide

1 Shaft magazine

2 Workpiece

3 Slide


5 Output shaft

Example 4:

Track distributor

1 Feed track

2 Track distributor


4 Workpiece

5 Output track

from clamping devices?

It takes little equipment to blow workpieces out of clamps using compressed air

or allow these to fall by gravity. The major disadvantage of this, however, is that

the orientation of the workpiece is lost. The first examples below show the use

of magnetic force. In example C, as the book block is released, it is stood on

edge and its direction of motion is changed. In the fourth example, the output

operation controls itself by mechanical means.

8 Output, alignment, branching58

1

2

A

3

4

B

1

23

4

1

2

3

4

C

D

1

2

4

3

5

6

8

Output, alignment,

branching

A Magnetic extractor

1 Electromagnet

2 Ferritic rail

3 Brass wedge to increase

air gap and allow detach-

ment of workpiece

4 Inclined track

B Magnetic gripper

1 Magnetic gripper housing

with appropriately-shaped

pole pieces

2 Coil

3 Ferromagnetic workpiece

4 Workpiece holder

C Output and alignment

1 Sliding track

2 Output workpiece, in this

case a book block

3 Rotary turning device

4 Spring-loaded output

device, yoke-shaped

D Self-controlling output

device

1 V support with drilled

bushing

2 Workpiece

3 Output trough

4 Spring-loaded

yoke-shaped output

device

5 V clamp = Metering device

6 Feed zone

1

23

4

5

12

3

4

5

1

2

3 4

5

1 2

3

4

5


32/55

What feed methods are often used with automatic machines?

Feed for automatic

What feed systems are used with grinding machines?

9


33/55

9 Feed devices

There are various feed devices, such as continuously vibrating and rotating

systems, rotors which hold workpieces during their motion, and also lever

mechanisms for infeed and outfeed.

63

machines

Example 5:

Feed of small workpieces

to an automatic packingmachine

1 Bin

2 Vibrator

3 Rotary table with driver

pockets

4 Conveyor chain with driver

5 Transfer position

Example 6:Feed of workpieces

to an automatic lathe

1 Shaft magazine

2 Input device

3 Separator

4 Drive cylinder

5 Workpiece removal device

6 Quadruple chain

Example 7:

Feed of workpieces

to an automatic grinding

machine

1 Workpiece

2 Metering device

3 Measuring/control device

4 Regulating device

5 Workpiece output

In view of the need to grind large quantities of standard components, the feed

systems used for this have long since been automated. The solutions concerned

are simple and reliable and provide a good example of dedicated feed systems.

9 Feed devices62

Feed devices

Feed for grinding

machines

Example 1:

Rolling track

1 Infeed track

2 Workpiece

3 Metering device

4 Input/output device

5 Outfeed track

6 Grinding disc

Example 2:

Chain

1 Chain buffer

2 Rotary feed device

3 Workpiece

4 Grinding disc

5 Outfeed track

Example 3:Conveyor belt

1 Magazine

2 Conveyor belt

3 Pair of rollers

4 Pair of surface-grinding

discs

5 Outfeed track

Example 4:

Feed chute

1 Drum bin

2 Vibratory feed chute

3 Grinding disc

4 Vibratory storage bin

5 Vibrator drive

1

2

3

46

5

1

2

3

4

5

1

2

3 4

5

123

4

5

1

2

3

4

5

1

2

3

4

6

5

1

2

3

4

5

How can circular blanks be fed by electromagnetic means?Can particular workpiece properties be exploited in feed devices?


34/55

9 Feed devices

There are numerous possible methods, generally involving an electromagnet

which picks the workpiece up. If this method is used with a stack, however,

several workpieces may stick together. In the example below, a gripper roller is

used to remove the workpieces from a magazine and place these on a roller con-

veyor [17].

65

1 2 3 4 5 6

987

3 5 4 2 1

N S N S N

1

3

2

4

Example 10:

Magnetic gripper roller

1 Power cylinder

2 Output roller conveyor

3 Castor

4 Roller conveyor

5 Magnetic roller

6 Circular blank, metal

stamping

7 Slide track for empty pal-

lets

8 Drive for magnetic rollerrotation

9 Pallet with compartments

Design of magnetic roller

1 Slip ring for power supply

2 Non-magnetic steel sleeve3 Ferromagnetic pole pieces

4 Solenoid coil

5 Axis

N North pole

S South pole

Sequence of gripping

operation

1 Approach to pallet

2 Lifting out a workpiece3 Tilting onto roller conveyor

4 Rolling away

Solutions which exploit particular workpiece properties generally produce well-

designed feed systems. These properties may be ferromagnetism, surface

resilience (wood) or particular frictional and rolling characteristics.

9 Feed devices64

Example 8:

Feed and fitting of pins

1 Bin

2 Pivoted lever

3 Permanently-magnetic

carrier wheel

4 Bracket

5 Feed tube

6 Lift cam for pivoted lever

7 Press-fitting cylinder

8 Metering device

9 Workpiece

10 Metering device drive

11 Base

12 Non-ferrous metalor plastic

13 Permanent magnet

Example 9:

Feed device for profile milling

machine

1 Magazine

2 Workpiece

3 Sensor for start

of metering device

4 Roller feed device

5 Milling station

6 Metering slide

7 Start pushbutton

8 Roller lever valve

9 Cam valve for return

stroke

10 Directional control valve

12

3

4

5

6

9

7

8

10

11

12

13

1

2

3 45

9

6

107

8

How can we separate long thin rods?How can spinning tubes be fed automatically?


35/55

Example 11:

Feed of conical workpieces

Detailed view of a tube hand-

ling station

1 Lifting device

2 Collector bin in emptying

position

3 Trough bin

4 Internal conveyor belt

5 Buffer store

6 Sleeve sorting station

(Cleaning station not shown)

Sorting operation

A The workpieces are

brought by a conveyor belt

to the tipping point.

B The sleeves are still justheld by the belt.

C The end with the smaller

diameter is released first

and is able to fall. A fast-

running conveyor belt

moves the falling work-

piece onwards, always

with the smaller diameter

leading (v2 v1).

9 Feed devices

It is difficult to remove long thin rods or pipes, plastic rails and similar work-

pieces from a trough, since the workpieces may be intertwined and there is no

guarantee that they will be in a partly-sorted state. One patented solution [18]

uses the principle of picking up one end of a workpiece and then running

rotating arms below this point. This gradually raise the rod from the bin. Once

the bar is fully raised, the arms are tilted to allow the workpiece to roll off.

Different methods are used to separate large rigid pipes.

67

1

2

1

5

4

3

2

7

6

10

4

1

1

10

9

8

7

3

Example 12: Pipe separation

and feed

1 Support arm

2 Holding trough

3 Gripper

4 Partially raised workpiece

5 Pulling device (chain)

6 Frame

7 Workpiece

8 Swiveling device

9 Lifting device

10 Support arm in tilted

position

Tilting angle

Ways of separating pipes

a Pressure gripping and

pulling out

b Pushing out

c Magnetic holding and

lifting

Ring spinning tubes are collected after use and must then be cleaned, sorted

and magazined. The tubes are 220 to 310 mm long and have diameters of up to

38 mm. They are conical. Sorting is carried out in two stages. A conveyor belt is

used to align the tubes by their longitudinal axis. A second stage is then used to

produce a uniform small/large diameter orientation (Brouwer & Co.).

9 Feed devices66

1

2

3 4

5

6

A

B

C

a

b

c

What do we mean by derivative feed motions?

E ti ithi f d d d i d t b t ll d W

What methods can be used to feed bar materials?

B f th i l th b t i l i i l t d f d t


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Example 13:

Feeding and buffering of long

workpieces

1 Ejector lever

2 Tapered roller conveyor

3 Rolling track

4 Frame

5 Lifting yoke

6 Transport beam

7 Special pallet

8 Workpiece

9 Pallet stacking location

A Transfer of bar material

for magazining

B Transfer of bar material

from buffer to roller

conveyor

Example 14:

Feeding glass flasks

1 Swivel magazine

2 Magazine rail

3 Yoke carrier in feed chain

4 Glass flask

5 Rotary axis

6 Swivel motion

for reloading

7 Filling zone

9 Feed devices

Every motion within a feed sequence needs a drive and must be controlled. We

therefore attempt to derive, or directly couple, any necessary feed motions to

other operations which are required in any case. This has been achieved in an

ideal way in the automatic knurling machine shown below. Skilful design has

made it possible to derive all the necessary feed motions from the pressing

operation.

69

1

2

3

8

9

4

10

A

B

C

5

6

7

Example 15:

Feed system

for an automatic knurling

machine

1 Knurling wheel

2 Workpiece, e.g. rotor shaft

of electric motor

3 Lifting and press-fitting

unit

4 Outfeed rolling track

5 Stop lug6 Finished workpiece

7 Support rollers in lifting

Vee

8 Metering device

9 Tension spring

10 Feed track

A The knurling operation

begins. Contact pressure

approx. 50 to 60 bar.

B The lifting Vee is loweredand sets the finished

workpiece down on the

back of the stop lug.

Simultaneously, the

metering device releases

the next workpiece. There

is no need for a special

controller for this.

C The new workpiece rolls

up to the stop lug. The

finished workpiece rolls

away to the left. During

the subsequent stroke of

the Vee, the workpiece is

picked up and then lies on

the support rollers.

Because of their length, bar materials require special storage and feed systems.

One solution can be to use large swiveling yokes to fill and empty special

pallets. In the example below, bar material is transferred from and to a tapered

roller conveyor.

9 Feed devices68

A

1 2 3

4

5

9 8

7

6

B

6

1

3

7

5

4

3

4

2

What are the points to note when feeding workpieces from a stack magazine?

The main problem is to ensure a constant flow of workpieces to the metering

What methods can we use to feed long cylindrical components?

There are probably more solutions for the feed of cylindrical components than


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Example 19: Feed from

a stack magazine

1 Moving half of magazine

2 Lever vibrator

3 Ball bearing

4 Detent pin

5 Rotary metering device

6 Cover plate

7 Workpiece output

a Metering device form

for workpiece diameters

6 mm, 60 to 200 mmlong

b For workpiece diameters

6 mm

I Rotor with vibrator cam

II Rotor with multple cells

for metering, vibrating

and locking

Example 20:Magazine filling device

1 Stack magazine

2 Deflector belt

3 Metering wheel, running

synchronously

with covneyor chain

4 Conveyor chain

5 Workpiece

6 Magazine

7 Light barrier as level

monitor

8 Metering device9 Feed to machine tool

9 Feed devices

The main problem is to ensure a constant flow of workpieces to the metering

device. Interruptions may occur due to bridge formation; to counteract this,

many types of vibrator devices are used. In the case of the magazine filling

device in example 20, a conveyor belt running against the outlet of the stack bin

is used to ensure a continuous flow of workpieces from this.

71

a

b

1

2

3

45 6

7

1 2 5

3

4

6

7

8 9

I

II

There are probably more solutions for the feed of cylindrical components than

for anything else, since this application is very common. Example 17 shows a

solution in which a stack magazine is used as a buffer store from which work-

pieces can be output again. A special gripper is required in order to pick up

workpieces from a stack at an angle (example 18).

9 Feed devices70

6

5 43

1

2

6

1

2

3

45

6

7

4

5

6

7

1

2

3

4

Example 16:

Feed of workpieces for thread

rolling

1 Workpiece

2 Output device,

self-swiveling

3 Input device

4 Metering device

5 Rolling track magazine

6 Examples of workpieces

Example 17:

Feeding or buffering of work-

pieces

1 Deflector

2 Roller conveyor

3 Workpiece

4 Thrust insertion device5 Return feed device

6 Metering device, barrier

7 Stack magazine

Workpiece diameters:

10 to 30 mm

Cycle time: 5 s

Example 18:

Feed of heavy bar sections

1 Handling device

2 Gantry carriage

3 Gantry support

4 Gripper

5 Roller conveyor as infeed

or outfeed device

6 Workpiece

7 Transport pallet

Angle, 60

Are special devices necessary to handle glass? (1)

Glass items are mass-produced with smelt temperature always a factor The

What is a good way of feeding light shaped workpieces?

Light shaped workpieces such as cans tubs and lids need to be fed with short


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9 Feed devices

Glass items are mass produced, with smelt temperature always a factor. The

special parameters with glass are thus primarily the effects of heat and the high

volume of production, rather than the shape of the workpieces. This is shown in

the examples. In the first example, glass tubes are lifted to transport them from

one pair of rollers to the next. They rotate on the rollers, which allows their ends

to be shaped, for example to be fusion-sealed. The second example shows a

feed system which is able to operate either cyclically or continuously.

73

1 2 3

45

6

7

8

9

10

1

2

3

A

56

4

7

2

1

A

Example 24:

Cyclical advance of glass

tubes (after Loewinger)

1 Output track

2 V-shaped bar for lifting

and advance

3 Workpiece

4 Support roller or disc

5 L-shaped lever for motion

transmission

6 Parallelogram lever

7 Roller lever

8 Cam for lifting motion

9 Motion for longitudinal

transfer

10 Return spring

Example 25:

Continuous feed of glass

tubes

1 Driver pin

2 Roller chain, double or

multiple running in parallel3 Sprocket

4 Bulk bin

5 Stack magazine

6 Workpiece (glass tube)

7 Chain tensioner

Light shaped workpieces, such as cans, tubs and lids, need to be fed with short

cycle times in processign and packing systems. The first example shows the

cleaning of cans, using a magnetic conveyor belt. The other examples show

further types of covneyors as alternatives to a vibrator. These exploit a

centrifugal conveyor principle. Sorting is generally carried out by other down-

stream devices.

9 Feed devices72

1

2

3

4

1

2

3

4

5

1 2 3 4

5

6

7 8 9

Example 21:

Handling cans

1 Magnetic conveyor belt

2 Workpiece (can open

at top)

3 Inward transfer track

4 Output of cleaned cans

5 Guide plate

6 Rotary output device

7 Spray nozzle

8 Feed zone9 Input side

Example 22:

Inclined-disc bin

1 Adjustable suspension

mounting of bin2 Workpiece already

on output track

3 Bin lining

4 Inclined disc, continuously

rotating

Example 23:

Conical disc centrifugal con-

veyor

1 Output track

2 Bin

3 Rotating conical disc

4 Base of bin

5 Motor with gear unit

Are pneumatic feed systems feasible?

Piece goods can also be transported on the principle of a pneumatic tube

Are special devices necessary to handle glass? (2)

Heating and cooling are major factors in the production of glass workpieces.


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Pneumatic feed

A - C Phases of feed operation

1 Workpiece

2 Openings

3 Feed tube

lw Workpiece length

l Distance to holder disc

m Workpiece mass

p Pressure in pneumatic line

v Peripheral velocity

F Thrust force producedby a vibrator

FR Frictional force

H Resulting force

k Coefficient making

allowance for the frictional

force between the work-

piece and pipe wall

s Minimum clearance be-

tween workpiece and hole

in holder

Pneumatic conveyance

of a piston motor valve

1 Pipe run

2 Compressed air

at velocity v

3 Workpiece at velocity c

Pneumatic conveyanceof ribbons and threads

1 Pipe run

2 Compressed air flow

3 Handling material

4 Injector with annular gap

9 Feed devices

g a a a p p p a p u a u

system. One particularly important factor is the transfer of workpieces into the

system. Pneumatics can also be used for the final phase of the motion inser-

tion into a workpiece holder. Endless threads or ribbons can also be transported

in this way. Here the axial air flow exerts a force on the belt, which is moving

more slowly due to air friction. This force conveys the ribbon continuously [19].

75

a g a g a aj a p u g a p

Cooling must take place slowly and is carried out in cooling or tempering zones.

Handling devices are required to re-orient the workpieces. The upper example

shows hollow glass workpieces being stood on end, while the second example

shows the handling of bottles. In order to prepare the bottles to pass through an

optical test machine, they must be formed into a string one workpiece wide. This

function is provided by the fast-running center outfeed belt.

9 Feed devices74

21

345

4 v1

v2

8

7

v2v2v1

1

2

3 4 5

6

9

Example 26:

Re-orienting glass workpieces

Workpieces which arrive in a

horizontal position need to be

stood on end for feed to the

next machine. The workpieces

are gripped at the top by their

blowing heads.

1 Hollow glass workpiece

2 Stop bar

3 Conveyor belt

4 Sprocket chain

5 Feed belt, v1 = v2

Example 27:

Formation of bottles into a

workpiece string (plan view).

Throughputs are achieved of

up to 10,000 units per shift

1 Cooling zone, hinged chain

2 Workpiece, e.g. bottle

3 Conveyor belt4 Guide plate

5 Center outfeed belt

6 Feed to test machine

7 Counterrotating belt

for excess workpieces

8 Guide plate

9 Guide web, fixed, v1 v2

1 2 3

A p v

B pv

C v

lw

FFFR

H

s

v

v

2 3 1

3 42 1

c

How can blanks be fed to shaping machines?

The process of feeding cutting and bending machines with circular or other

How can flat pallets be handled automatically?

Automatic pallet handling can be necessary for two reasons to activate a


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9 Feed devices

p

blanks is determined by one factor in particular the distance between the

magazine and the point of action of the machine. For constructional reasons,

magazines cannot be positioned directly adjacent to this point.

77

Handling small blanks

1 Metering slide,

single-acting

2 Magazine shaft

3 Gravity shaft

4 Deep-drawing tool

Feed in mm Strokes per min.

20 150

20 40 100 120

Tapered-slide metering device

1 Metering slide,

double-acting

2 Taper drive

3 Drawing tool

4 Cutting tool

5 Clamping pin


20 150

20 40 100 120

Metering slide

with pneumatic drive

1 Magazine shaft

2 Metering slide


4 Punch tool

E Limit switch


50 250 30 60

Metering slide driven

by press ram

1 Magazine shaft

2 Angle lever

3 Metering slide


20 14020 50 100 120

p y

passive pallet in order to be able to work with simple handling devices (point

access), or to create large buffer stores upstream of or between machines. The

technical solutions used range from simple switching-cam rollers to complex

pallet stores.

9 Feed devices76

Pallet indexing device

1 Pallet frame

2 Indexing stop

3 Switching roller

4 Cam

5 Double cylinder to pro-

duce 3 switching positions

(stop 1, stop 2, run-

through without stops)

l Step width during indexing

Stacking/destacking unit

1 Full pallet stack

2 Handling device

3 Empty pallet stack

4 Stacking unit

5 Destacking unit6 Lateral slide

Shaft buffer unit

1 Shaft with guides

2 Flat pallet, crate, etc.3 Retainer

4 Roller conveyor

5 Lifting/lowering device

6 Stop device

1

2

43

5l

1 2

4

3

6

5

1

2

4

3

6

5

1

2

4

3

5

124

3

1

2

4

3

EE

1

2 3

Do transfer devices need to be matched to materials?

Automatic transfer from one machine to the next is vital in high-throughput

Can all types of bolts be fed equally easily?

The answer is no! Bolt feed devices must take into account the behavior of the


41/55

9 Feed devices

installations. In these cases, an optimum solution can be achieved only if hand-

ling devices are closely matched to the properties of the workpieces concerned.

In the case of cans, for example, these are first formed into groups and then

gripped as a block. If the cans were handling individually, this would lead to very

short cycle times. The second example, too, has been specially designed to deal

with pipe or bar material and uses a custom-made metering disc to transferworkpieces from the rolling track to the longitudinal conveyor. The shape of the

driver compartments eliminates the need for any further retaining plates or

similar.

79

1

2

B

3

4

5

1

2

3

4

56

7

8

2A

A Transfer of cans

1 Transfer gripper device of

a gang press (output side)

2 Workpiece, hollow sheet-

metal with base upper-

most3 Handling device

4 Multiple suction cups

5 Permanent magnet

6 Switchable electromagnet

7 Conveyor belt

8 Collector conveyor belt

B Transfer of pipes

1 Metering disc

2 Driven tapered roller of a

longitudinal conveyor zone

3 Step stop

4 Rolling path with or with-

out steps to align rolling

pipes

5 Workpiece, pipe or bar

A Feeding bottom-heavy

bolts

1 Angle rail

2 Covered parallel rail

3 Feed pipe or tube

B Feeding top-heavy bolts

1 U rai l

2 Profile tube

3 Turning by inverter rail

after conveyance

from vibrator

4 Turning by turning unit

C Difficult bolt shapes

Flat-head bolts can overlap,

small-head bolts may tilt in the

rail, and combination bolts

may lock together head to

head.

s t

bolts during feeding. The major factors are the position of the center of gravity,

the length, the shape of the bolt head, the ratio of diameter to length and the

presence of surface coatings. Bottom-heavy bolts will hang on rails and can also

be fed effectively using chutes. Top-heavy bolts, on the other hand, must be pre-

vented from falling over. These can be fed effectively in profile tubes and rails.

Difficulties will be experienced with all bolts whose heads have a tendency tolock together, tangle or slide one inside the other.

9 Feed devices78

2A 31

B

1 2

3 4

C


42/55

Should we check features in the main workpiece flow? (2)

Incorrectly-oriented workpieces can cause feed mechanisms to jam, particularly

h th k i t i l Si l it i d i hi hl

9

Feed devices

Should we check features in the main workpiece flow? (1)

If this were done in cases where the proportion of defective workpieces to be

li i t d l ti l hi h thi ld t i h dli it i t


43/55

9 Feed devices

when the workpieces are asymmetrical. Simple monitoring devices are highly

advisable in order to protect machines and equipment. The automatic elimina-

tion of incorrectly-oriented workpieces is effectively the same as sorting work-

pieces and can thus utilize several of the same principles.

83

A B

C

Workpiece

D

1

23

4

h

a

5

A Hook spring

The hook engages in the slot

of incorrectly-oriented work-

pieces and pulls the workpiece

concerned off the track.

B Slide track with opening


pieces do not lie on the

suspension rail and fall

through the opening.Condition: a b

C Profile check

The set screws in the feed

trough are adjusted to match

the profile of a correctly-

oriented workpiece.

D Slide track with lifting

ramp [15]

If blanks which are too long

are accidentally inserted into

the feed track, they are raised

and, for example, ejected

upwards by an air jet.

a = h 1 mm

eliminated was relatively high, this would mean turning a handling unit into a

test machine. This would not be correct. It would be better in these cases to

install test stations upstream. If, on the other hand, faults occur relatively

seldom, it is often possible to incorporate very simple mechanical checks,

particularly of geometrical properties. Each incorrect workpiece, however, means

an interruption in the workpiece flow and generally requires a manual inter-vention [15].

9 Feed devices82

A1 2

B

11 2

C

12

Goodworkpiece

Badworkpiece

D

1

2

Goodworkpiece

Badworkpiece

A Checking a welded

assembly

Base components without

welded-on pins are eliminated.

1 Complete assembly

2 Base component

B Check of progress

of machining

Workpieces without a

machined recess will not fit

into the shape-monitoring

magazine (left).

1 Correctly-machined

workpiece

2 Incorrectly-machined

workpiece

C Check of diameter

All workpieces deviating

from the check dimension

= 0.5 (D+d) are held back.

1 Roller diameter D

2 Pivot diameter d

D Checking brush assemblies

Workpieces with a brush insert

missing on one side slide

crookedly and are held back

by a monitoring lug.

1 Workpiece (brush

assembly)

2 Slide trough

What are the typical forms in which industrial robots are produced?

By form we mean the configuration of the modules of a machine. This is the

result of a process of adapting the robot for a certain handling task taking into

10

Handling systems

How can we guard against two workpieces being fed at once?

Accidental feed of two workpieces at once occurs particularly with flat work-

pieces; this interrupts the flow of work and may lead to serious damage to

Monitoring for double

sheet-metal work-

pieces


44/55

10 Handling systems

result of a process of adapting the robot for a certain handling task, taking into

account operating conditions and other restrictions and the basic design

parameters of the robot in question (structure).

85

Industrial robots

Designs

1 Column form

2 C-frame column form

3, 4 Column fo rms

5 Column form

with traveling axis

6 G antry form with wall

mounting

7, 8 Gantry form with one

or two columns

9 Special form

with double arm

10, 11 Special forms

Basic design

Sequence of rotary and

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