What is a lever clamp?
A lever type clamp is a clamp that has a shape of a mechanical lever. The lever clamps are used to rigidly hold the workpiece with the fixture and keep it stable against all the distributing forces during a machining process.
Lever type clamps are simple in design and are widely used as clamping devices in jig and fixture.
Well, this was a short introduction about the lever clamps. But further I have explained different types of lever type clamps along with their images.
So let’s dive right into it!
Different types of lever clamps
There are basically 4 types of lever type clamps used in jig and fixture.
- Bridge clamp
- Heel clamp
- Swinging strap (latch) clamp
- Hinged clamp
Let’s discuss each of these lever clamps one by one.
#1) Bridge clamp
Bridge clamps are simple and reliable clamping devices in which the clamping force is applied by spring loaded nut.
The clamp should be positioned properly because the sharing of compressive force depends on the distance of the nut from the workpiece.
If the distance between the nut and workpiece is more, then the less compression force will be exerted on the workpiece. And if this distance is less, then the compression force on workpiece will be more.
As shown in the above image, the distance X should be less than or equal to distance Y, so that the workpiece remains property compressed with the fixture.
The spring is also fitted with the clamp which allows its easy lifting when the nut is loosened.
The slot is provided in the clamp which allows its easy adjustment during the fitting.
Two way clamping can also be achieved by using a bridge clamp as shown in the above image.
#2) Heel clamp
The heel clamps consist of a solid heel or a heel pin, a plate, strud, spring and a spherical washers.
The heel clamp is similar to that of bridge clamp, but it has a heel at the outer end of the clamp.
Above image is of a solid heel clamp which has a solid heel and a stop pin near the heel to prevent the rotation of the clamp during its fitting.
The spring is provided on the clamp which helps its unloading when it is unscrewed.
In order to unload the workpiece, the clamp is rotated in an anticlockwise direction.
After this, the new workpiece is loaded and the clamp is rotated back to its position and the nut is tightened to press the workpiece with a fixture.
When there is no use of clamp, it is turned 90° and this position is called “off-position”.
Sliding type heel clamps
Sliding type heel clamps are special types of heel clamps which have different designs according to specific applications.
The sliding clamp consists of a slot in a clamp plate through which the clamping stud is passed.
The small diameter is provided at the upper end of the heel pin which helps to fit the pin in the keyway of the clamp.
Hence the heel pin can be moved to and fro just by pushing it.
In some fixtures, the stem is provided in cases where the workpiece has more height and the heel pin is mounted in this stem.
Sliding clamp with adjustable heel pin
In this type of clamp, the adjustable heel pin is used and this is very useful in early machining operations.
This is because the height of the workpiece is more (and it changes frequently in the starting operations) so the adjustable heel pin is very beneficial to hold the workpiece.
#3) Swinging strap (latch) clamp
Swinging strap type clamps are the clamps which swings out or in.
The strap (or latch) may have various variations in shape, holes, slots, etc but the common method of swinging the strap out and in remains the same.
You can see the two different designs for latch clamps in the above image.
#4) Hinged clamp
Hinged clamps are the type of clamps in which the latch is hinged to enable the workpiece loading and unloading.
The hinged clamp can be locked with the help of a bolt (figure (a)) or a hoot arm (figure (b)).
Hinged clamps are easy to operate and they can be operated quicker than the bolt type clamps.