Clamping Techniques

A selection of gage clamping techniques is shown in the sketches that follow:

• Spring Clamp Direct Mode
• Spring Clamp Reverse (Pushing) Mode
• Hose Clamp Cylindrical Surface
• C-Clamp/Helical Spring Two Opposed Surfaces
• Block/Helical Spring Single Surface
• Rubber Band Wrapped Structure
• Silicone Rubber Plug Inside a Through Hole
• Silicone Rubber Tubing Inside Pipe or Blind Hole
• Vacuum Pad Commercial
• Vacuum Pad Homemade

Whether one of these or another clamping scheme is used, there are two precautions that need to be observed in every case. The first is to always apply the clamping force through some form of spring (preferably low-rate). Rigid clamps ( C-clamps , hose clamps , etc.) should not be used without a spring in series with the clamping force. The spring is necessary to ensure that the force does not vary significantly with small dimensional changes which may occur as the adhesive flows and cures, or as the temperature changes. The second is to always provide a means for determining the actual clamping force, thus making certain that it is within the range specified by the supplier. This can be done by precalibrating the spring for force versus deflection, or by direct measurement on the clamping assembly with an inexpensive spring scale (e.g., a "fish scale").

The selection of additional clamping methods is limited only by the imagination of the gage installer. Following the guidelines provided in this publication, there should be very few applications where adequate gage clamping pressure cannot be achieved.

For further assistance in applying the clamping techniques illustrated, contact our Applications Engineering Department.

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