Cam trigger

[Jonathan W.]

Hi Teams,

For a kicker design, we are looking at using a large L bracket attached to a spring posed to pull it clockwise in some manner. A motor driven cam would turn clockwise against the bracket and act as the trigger. The rough CAD (please don't bash the CAD)

Opinions or advice? Have any teams implemented this type of design before? We specifically need input on a safety release method. (i.e. releasing a cocked kicker with our power cut)

[MrForbes]

I came up with a similar design, but the cam's axis of rotation is vertical, not horizontal.

We want to make our kicker have adjustable range, and it looks easier to accomplish that with a winch.

[Kevin Sevcik]

Well you likely won't be able to rotate the cam safely with the power off. Why don't you put your springs/elastics on something you can release to slacken them? If you attach them to some kind of sliding/swiveling plate then you can lock the plate in place for competition with yet another cam, and let up the pressure on the plate to relieve tension on the springs.

[Jonathan W.]

Thanks! Hopefully we will keep all our limbs this season.

[Jonathan W.]

We are doing some preliminary calculations on the torque required to turn this cam. We picked out some springs (Lee Spring part # 177P 03 S), and did a feasibility calculation. We ended up with 32.17 N*m required to turn the cam a final increment as the spring is at nearly full extension. (80 lbs of force). See attached work. We assumed that the spring would be attached directly to the point where the Cam contacts the kicker arm, and that there is no friction.

Is this 32.17 N*m answer reasonable??? (lifting a bit more than half a robot)

Thanks