Clamps

Question 1

elements hold the workpiece firmly engaged with the locating elements during operation

Answer 1

Clamping

Question 2

The clamping system should be _____ developed during operation.

Answer 2

strong enough to withstand forces

Question 3

clamping force should ______ the workpiece.

Answer 3

not dent or damage

Question 4

What is the purpose of clamping device

Answer 4

Clamping Device purpose is to hold work in the correct relative position in the fixture and to ensure that the job is not displaced under cutting forces

Question 5

In the design of efficient clamping devices, the following points should be considered:a.

Answer 5

1. The rotary or reciprocating movement of clamp should be avoided as far as possible.

Question 6

In the design of efficient clamping devices, the following points should be considered:

Answer 6

2. Arrangements should be made to lift the clamp away from the work, or otherwise clear it, when the clamping load is released. This can be achieved by employing compression springs.

Question 7

Basic Rules of Clamping Device:

Answer 7

A. Clamps should always contact the work at its most rigid point.

Question 8

Basic Rules of Clamping Device:b

Answer 8

Clamps should be positioned such that they do not interfere with the operation

Question 9

Basic Rules of Clamping Device:c

Answer 9

Tool forces generated by cutting action should help in holding the work piece instead of lifting or tilting it.

Question 10

Basic Rules of Clamping Device:d

Answer 10

d. The type and amount of clamping force (force required to hold a part against the locators) needed to hold a part is usually determined by the tool forces working on the part and the way the part and the part is positioned in the tool.

Question 11

The clamping system should be capable of holding the workpiece against the forces developed during the operation.

Answer 11

Strength

Question 12

Clamping time should be minimized by using hand knobs, tommy bars, knurled screws, hand wheels and handles

Answer 12

Productivity

Question 13

should be taken into account. If a considerable number of clamps are to be tightened and loosened repeatedly, it is better to use pneumatic or hydraulic clamping which, in addition to reducing operator fatigue, also saves clamping time.

Answer 13

Operator fatigue

Question 14

The clamping points should be provided with ample radius to make the clamp operable even if there is variation in the workpiece.

Answer 14

Clamping Variation

Question 15

This is the most popular clamping device used in workshops, and tool rooms of jigs and fixtures.

Answer 15

Lever of Strap Clamps

Question 16

These are widely used for jigs and fixtures. These have lower costs. However, their operating speed is quite slow

Answer 16

Screw Clamp

Question 17

. The basic screw clamp uses the ______ developed by a screw thread to hold a part in place.

Answer 17

torque

Question 18

The efficiency of the screw clamp can be improved by using

Answer 18

swing clamps, hook clamps and quick acting knobs.

Question 19

Swing clamps combine the screw clamp with a swinging arm which

Answer 19

pivots on its mounting stud.

Question 20

when properly selected and used, provide a fast, efficient, and simple way to hold work, (Refer Fig. 8). Due to their construction and basic operating principles, the use of cam-action clamps is limited in some types of tools.

Answer 20

Cam-action clamps,

Question 21

These utilise hinged lids for loading and unloading the components. Generally the clamp is made integral with the hinged lid. Fig. 9 shows an arrangement using combination of hinged clamp and hinged bolt.

Answer 21

Hinged Clamps

Question 22

rapid clamping in two directions from one screw. Clamping force is applied to the top and one side of the work piece. The clamp has a quick release action.

Answer 22

Two way clamp

Question 23

are self-holding type and normally hold the work without additional attachments. Large angel (self-releasing) wedges are used where large movement is required

Answer 23

Wedge Operated Clamps.

Question 24

:
These provide a fast, efficient, and simple way to hold work. If cam clamps apply pressure directly to work and work is subjected to vibration, then clamp may loosen and such clamp should not be used.

Answer 24

Cam Operated Clamps

Question 25

The advantages of cam action can be obtained in indirect clamping method by .

Answer 25

using cam action rather than screw threads to bind strap clamps

Question 26

There are three basic types of cams used for clamping mechanisms:

Answer 26

Flat eccentric, flat spiral, and cylindrical

Question 27

_____ cams are easiest to make and can operate in either direction from their center position

Answer 27

Flat eccentric

Question 28

:
These are fast acting clamps. These have the natural ability to move completely free of the work, allowing for faster insertion/taking out of parts.

Answer 28

Toggle Action Clamps

Question 29

toggle clamps compared to the application force is very high. Fig. 13 shows the four basic clamping actions, viz. .

Answer 29

hold down, pull, squeeze, and straight line action

Question 30

may operate under hydraulic power, pneumatic power, or with an air-to-hydraulic booster. The ______have better control of clamping pressures.

Answer 30

Power Activated Clamps

Question 31

Commercially available chucks and vises with slight modifications of jaws to suit the job can be used for a variety of applications.

Answer 31

Chucks and Vises

Question 32

can be easily modified to suit practically every clamping need

Answer 32

Blank vise jaws and blank chuck jaws

Question 33

like magnetic and vacuum chucks are used to hold parts which are difficult to be held by other devices because of their size, shape, or fragile nature

Answer 33

Non-mechanical clamps

Question 34

Magnetic chucks may either use

Answer 34

permanent magnets or electro-magnets.

Question 35

Magnetic chucks are obviously suitable for .

Answer 35

ferrous parts

Question 36

Vacuum chucks equalize the?

Answer 36

clamping pressure over the entire clamping surface

Question 37

Vacuum chucks are suitable for ________,particularly where uniform clamping is required.

Answer 37

almost every machining operation,

Question 38

To clamp smaller parts, the exposed chuck ports can be covered with .

Answer 38

a mask, or closed by tightening the special part screws

Question 39

Principles of Clamping

a)

Answer 39

Position clamp on a strong supported part of the workpiece, clear of the workpiece loading/unloading of the cutting tool paths.

Question 40

Principles of Clamping


Answer 40

Clamp strength should be adequate to withstand operational forces without damaging the workpiece.

Question 41

Principles of Clamping
 c)

Answer 41

Quick operation without spanner (knobs, levers).

Question 42

Principles of Clamping
d).

Answer 42

Compensation for variation in the workpiece through radii at clamping point and on the heel pin , use of spherical washers, and equalizers (in multiple clamping).