Non-Bridging Post Clamps are in full contact with the underlying optical table or breadboard along their entire length, eliminating any localized deformation of the clamp, optical table or breadboard when tightening the mounting screw.  Non-bridging clamps therefore greatly reduce any potential optical pitch/yaw misalignment introduced due to torque effects on the slot clamping mechanism.

Purpose:

Simulations were performed to compare the deformation caused by an industry-standard clamping fork vs. the non-bridging clamping fork and to estimate if permanent deformation to the table would occur or not.

Results:

With a standard clamping fork (left), the table deforms at a maximum of .0074 in. when torqued to a maximum of 75 in-lb. In the areas surrounding the fork, deflections are much less. Under static conditions, the von mises stresses around the clamp exceed the table’s yield strength by less than 10%, thus small permanent deformation around it can occur.

With a non-briding clamping fork (right), the table deforms at a maximum of .00058 in. when torqued to a maximum of 75 in-lb. In comparison to the industry standard, the deflections are greatly reduced. Under static conditions, the von mises stresses around the clamp are far less than the table’s yield strength resulting in significant margins of safety for yield and ultimate strength, thus any permanent deformation is unlikely.

Purpose:

This test was performed to determine the ideal clamping torque applied to the flexure that is necessary to securely mount a 1 in. optical post within the bore of a non-bridging clamping fork.

Method:

NBC-1 was used in this test and first mounted to an optical table. The flexure clamping cap screw was tightened by a torque wrench to specific torque values. An increasing rotational torque was applied to the optical post until it moved within the clamping arm's bore. The torque value right before it moved was recorded as holding torque.

Results:

To securely hold a 1 in. optical post, the flexure clamping screw should be tightened with 20-30 in-lb of torque for optimal performance.

Purpose:

This test was performed to determine the ideal mounting torque applied to the cap screw in the slot that is necessary to securely mount the clamping fork to the optical table. The mounting screw was installed in different positions within the slot to see if the recommended torque would vary.

Method:

The non-bridging clamping fork was mounted to an optical table by a cap screw in the slot. Three locations were tested: close to the post, in the middle of the slot, and far from the post. The cap screw was tightened by a torque wrench to specific torque values. Three locations An increasing rotational torque was applied to the clamping fork until it moved on the table. The torque value right before it moved was recorded as holding torque.

Results:

To securely mount the clamping fork to the optical table, the mounting screw in the slot should be tightened with 40-60 in-lb of torque for optimal performance.