I am stuck on a "design of machine components" project. Anyone care to take a crack? Its actually a pretty simple spring problem.
I am messing around with the design for a helical torsion spring but am having trouble finding part of the force.
Specifically the spring
that is used on the end of barbells to prevent plates from sliding. I do not know how to determine how much force the spring is putting on the bar.
What i figure is it has to do with the coefficient of friction, number of coils, diameter of the inside of the coil**, etc.
My professor who is a goof ball told me to solve for the angular spring rate, does that sound right?
**as it is a helical spring, when the handles are forced towards each other the numbers of coils increases (i.e. 4.375 turns --> 4.5 turns). As this happens how does the inner diameter change? How does this effect the force when the original diameter is a little smaller then the diameter of the barbell (lets say the barbell is 2 inches and the UNFORCED spring is 1.9, forced its 2.1...)
As you can see I am a little lost....I know the hive mind is usually not so good at engineering questions but I thought I would ask anyway.