Hydraulic Clamping Fundamentals

Repeatability: Is defined as the allowable angle tolerance of the arm as it contacts the part, with out any outside influence. Repeatability is independent of swing angle and is ± 1½ ° on all families except High-Speed. Repeatability on the High-Speed swing clamp is ± ½ ° . There may be instances in your application when you do not want, or cannot tolerate clamps rotating the full Swing Angle. Optional swing restrictors are available that reduce the included angle of the unclamp swing, which will reduce the total/rotational stroke of the unit.

switches in the unclamp line to convey feedback information to a computer, or controller. Large or custom arms may also require the use of a double acting device to insure that the arm can be lifted, or unclamped. Swing clamps are subject to a reduction of force due to friction and cantilevering of internal components. This is also affected by the “load couple distance” (variable arm length) relative to the “force couple distance” (non-variable clamp components). The following illustration depicts the “cantilever reaction vectors”, “force couple distance”, and “load couple distance” that is inherent to devices such as swing clamp.

Typically, the swing clamp should be installed so that when the arm engages a nominal work- piece, it is at one half of the clamp stroke. This will allow for compensation of work piece dimensional variables. The maximum functional system backpressure a single acting swing clamp can readily overcome is 10 psi. If the backpressure during the return, or unclamp cycle is greater than this, the swing clamp will be slow to extend (unclamp), or possibly not extend at all. In automated or robotic load and unload applications, double acting clamps should be used when ever possible. The hydraulic pressure applied to the return, or unclamp side of the piston (as opposed to a mechanical spring) will help insure that the clamp arm is unclamped, or “out of the way”. Double acting systems also permit the use of devices such as pressure

This reduction of force has been taken into consideration before publishing the capacity of VektorFlo® swing clamps and arm lengths. The

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