Quote:
Originally Posted by Al Skierkiewicz
Remember that the forces on the cross screws are greatest when the tensioner is receiving forces from the chain in motion. You may not bend the screws while tensioning but I bet you will in a pushing match with anotheer robot.
|
Let's throw some numbers at this assume that while being pushedmost of the wieght is transferred to one wheel (100 pounds) and it is slipping give a coefficient of friction at 1.2(ish) and you have 120 pounds. for a 6 inch wheel this is 360 inch-pounds of torque in the system (120 pounds x 3 inch radius). If it is a 2 inch sprocket at the wheel, the chain force is then 1080 pounds. This gets added onto the tension that you put into the system. You can then run the calculation for the bending stress in a round beam constrained on both ends and then loaded in the middle (make sure you use the root diameter of the bolt if it is all thread).
We use two tensioners on each dead axle so that they are essentially in shear. Not only do they share the lods, but then you can directly connect them to the axle.