Week 34 Flashcards
elements hold the workpiece firmly engaged with the locating elements during operation.
Clamp
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.
Clamping devices
The clamping system should be capable of holding the workpiece against the forces developed during the operation.
STRENGTH
Clamping time should be minimized by using hand knobs, tommy bars, knurled screws, hand wheels and handles, so that the clamp can be tightened or loosened manually without using spanners, as a spanner further add motions of picking, aligning, and laying it down.
PRODUCTIVITY
Operator fatigue 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.
Operator fatigue
The clamping points should be provided with ample radius to make the clamp operable even if there is variation in the workpiece.
Workpiece vibration
This is the most popular clamping device used in workshops, and tool rooms of jigs and fixtures.
Lever of strap clamps
These are widely used for jigs and fixtures.
Screw Clamps
when properly selected and used, provide a fast, efficient, and simple way to hold work.
Cam-action clamps
These utilise hinged lids for loading and unloading the components. Generally the clamp is made integral with the hinged lid.
Hinged clamps
shows an example of rapid clamping in two directions from one screw. Clamping force is applied to the top and one side of the work piece.
Two-way clamps
shows the operation of wedge operated clamps in which the horizontal movement of the wedge causes upward vertical clamping force on the work piece.
Wedge operated clamps
These provide a fast, efficient, and simple way to hold work.
Cam Operated Clamps
These are fast acting clamps.
Toggle action clamps
