Operating principle of toggle clamps

Operating principle of
Toggle clamps

By using the toggle link principle these toggle clamps offer decisive advantages:
The clamping arm retracts to such an extent that the workpiece can be loaded and unloaded completely unobstructed.

Even the slightest forward movement of the operating handle brings the clamping arm with the contact pad over the workpiece.
As can be seen from the sketch, the position of the toggle links will lead to a multiple of the input force applied to the operating handle.
In this position the Toggle clamp is not yet fully engaged and any counter force will open it.

In this position all three pivots are perfectly aligned yielding the maximum clamping force Fs (dead centre point).
The clamping force Fs exerted on the workpiece is mainly dependent on the following criteria:
the input force which is applied to the operating handle,
the position of the clamping bolt on the clamping lever.
Since the applied force on the lever by the operator is not known, the clamping force Fs shown in the table is only specified for pneumatically operated clamps.
The clamping force Fs can be altered by re-adjusting the position of the clamping bolt. The clamping force increases if the entire contact area of the bolt arrives on the workpiece prior to the toggle linkage reaching dead centre point. This effect is illustrated clearly when using an elastic clamping pad.

In this position the toggle linkage has arrived in the over-centre lock position and the operating lever has reached a firm stop and is thus prevented from opening until it is released by the operator.
The force which the clamp is capable of withstanding in this over-centre lock position without suffering permanent deformation is known as holding force FH. The holding force has a characteristic value (co-efficient) for toggle clamps and this value is mainly dependent on:
the size (dimensions, geometry) of the toggle clamp,
the position of the clamping bolt on the clamping arm.
In the tables the holding force FH of the toggle clamps is given in each case in relation to a particular position of the clamping arm.
All clamps are shown on the standards sheets in their clamping position.
All references to force are given in N (Newton) ~ = 0,1 kp.

	By using the toggle link principle these toggle clamps offer decisive advantages: The clamping arm retracts to such an extent that the workpiece can be loaded and unloaded completely unobstructed.
	Even the slightest forward movement of the operating handle brings the clamping arm with the contact pad over the workpiece. As can be seen from the sketch, the position of the toggle links will lead to a multiple of the input force applied to the operating handle. In this position the Toggle clamp is not yet fully engaged and any counter force will open it.
	In this position all three pivots are perfectly aligned yielding the maximum clamping force Fs (dead centre point). The clamping force Fs exerted on the workpiece is mainly dependent on the following criteria: the input force which is applied to the operating handle, the position of the clamping bolt on the clamping lever. Since the applied force on the lever by the operator is not known, the clamping force Fs shown in the table is only specified for pneumatically operated clamps. The clamping force Fs can be altered by re-adjusting the position of the clamping bolt. The clamping force increases if the entire contact area of the bolt arrives on the workpiece prior to the toggle linkage reaching dead centre point. This effect is illustrated clearly when using an elastic clamping pad.
	In this position the toggle linkage has arrived in the over-centre lock position and the operating lever has reached a firm stop and is thus prevented from opening until it is released by the operator. The force which the clamp is capable of withstanding in this over-centre lock position without suffering permanent deformation is known as holding force FH. The holding force has a characteristic value (co-efficient) for toggle clamps and this value is mainly dependent on: the size (dimensions, geometry) of the toggle clamp, the position of the clamping bolt on the clamping arm. In the tables the holding force FH of the toggle clamps is given in each case in relation to a particular position of the clamping arm. All clamps are shown on the standards sheets in their clamping position. All references to force are given in N (Newton) ~ = 0,1 kp.