Some Frequently Asked Questions about Toggle Clamps

What is a Toggle Clamp

One of the most basic questions is ‘What is a Toggle Clamp’. It’s a very good start when looking at this versatile piece of kit.

All of this type of clamp have three distinct elements, their Action, Linkage and Handle (also known as the Actuator)

The three together result in a quick acting mechanical linkage which works like this:

When the operator (who can itself be a machine) moves the actuator to its mid position it starts to apply clamping pressure to the workpiece (this is achieved by stretching the linkage element). Moving the Handle past the mid point then locks the action. This is referred to as the ‘toggle lock’.

You may also have come across the term ‘Clamp Action’.

This refers to the basic function of the device, that is to apply holding and clamping force on the workpiece or job.

Another term is ‘Air Operated Action’.

This is one way of automating the use of Toggle clamps, no human action being required to move the handle, this instead being carried out using a pneumatic cylinder. The type of clamps that can be used in this manner are the ‘Hold Down’ and ‘Push Pull’ variants.

This of course leads to the question ‘What is Hold Down Action’?

This is the most used version of Toggle Clamps, the term ‘Hold-Down Action’ refers to the way the clamping force is applied downwards,  perpendicular to the surface the clamp is mounted on.

Hold-Down action clamps can be either Horizontal& Vertical.

Yet another term is ‘Linear Action’

Whilst Hold Down clamps apply force in a perpendicular manner, Linear Action clamps apply their force parallel to the mounting surface and are usually used to force two components together or to force one against a solid stop.

Linear action clamps can be supplied in ‘Drawbar’, ‘Latch’, ‘Hook’, ‘Threaded Rod’, ‘Push’, and ‘Push Pull’ versions.

Then there is the question, ‘What does Holding Capacity mean’?

Every clamp has a “holding capacity”, this referring to the maximum force it can apply in its locked position without being permanently deformed. Please check out the specs of any clamp you are using if in doubt.

Yet another question is ‘What is the Clamping Force’?

Clamping force refers to the level of force applied to the job piece when the clamp is closed and locked. The maximum force that the tool can apply is normally about 80% of the ‘Total Holding’ Force the clamp can supply.

Then there is the matter of ‘Applied Force’, and what it is?

All types of clamps require some physical force to move them into the holding / clamping position. This force is known an ‘Applied Force’ and is measured by the level of force that has tobe applied to the handle to provide the maximum clamping force. It is hard to calculate this level as there are so manyvariables involved. Among these are the type of clamp type, the position of the spindle position, not to mention the material beingclamped.

Lastly, there is the question ‘What are Positive Lock (-P) Clamps’?

Certain clamps are available with what is known as a PositiveLock (-P) feature. This is also known as a secondary lock. This is very useful in conditions where the handle could be moved unintentionally, something that would result in the piece being held to be released, with what could be dire results.

Thus, these locks are used in places where it is possible that the clamp handle could be accidentally moved, such as environments where the clamp is exposed to a number ofrepeated shocks or a level of vibration that might just make the toggle clamp spring open.

We hope that this brief article on Toggle Clamps has answered some of your questions and helped you to understand what type of Toggle clamp you should purchase, but if you are in the slightest doubt, could I suggest that you contact the industrial automation experts at Sandfield Engineering? They have decades of experience in Engineering and can help solve even the most complicated engineering issue. They also assist in speeding up production lines and have a range of automation products to offer.

Basically, if you have an engineering problem that you cannot solve, please do contact them. I know that they will be able to help and that quick chat could save you a lot of time and money. Their page on their website about toggle clamps can be found at :-


Sudarsan Chakraborty is a professional writer. He contributes to many high-quality blogs. He loves to write on various topics.