Wanted: Carriage Lock Mechanism for Round Shaft

How much force does the brake (clamp) need to withstand?

We have done similar things a couple of different ways, although the positioning was done by air cylinder and clamped in place when position was reached. We also had our own machine shop make an air cylinder-operated clamp for the linear shaft. We also made a device for a screen printer which was moved by hand and electromagnetically clamped to the rail when it reached the proper position. Again, our machine shop made a split cylinder end for a solenoid armature to ride against the linear rail and be actuated when correct position was detected by proximity sensor.

This lock up would be manual only. Enough force to prevent movement with a side load of approx. 200 lbs. We did this once before using a knob with a threaded shaft. The main plate was tapped over the quadrant of both shafts. So turning the two knobs pushed on the shafts to prevent movement. The entire carriage weights about 1500 lbs. I pursued a clamp collar fixed to the carriage but i was reluctant as the collar may create binding issues when the operator pushed the carriage, and the collar would require a hex wrench the operator would need to find when doing a quick setups.

I would not do the clamping on any bar part of a linear bearing. Those are usually fairly precise and lubricated. Both of those qualities are incompatible with clamping (friction brake). Adding a third, dry bar in the middle you can clamp away to your heart content. Assuming 0.05 friction coefficient divided by 2 or 3 for safety factor, you know the necessary clamping force. Produce it in a balanced fashion: a scissor arrangement normally freely sliding on the third bar, just bracketed by the working table. That way it wont transmit any part of the clamping force to the table, causing distortion.

Company called Lintech Motion

http://www.lintechmotion.com/pdffiles/Lintech_Components%202008-05.pdf

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