Disengaging a motor on a spring powered hurdler

[Daniel Bathgate]

We are working on a hurdler design that will use a large spring to hopefully accelerate the trackball enough to clear the overpass. Since safety will obviously be a concern, we will mount the spring in a protective cylinder, have a cable running through the center of the spring, use at least two strong latches to hold it in place when loaded, have a way to release tension in the spring safely without firing the mechanism, and use a two step process to fire the hurdler on the operator panel to help prevent accidental firing. (Comments on the safety of such a device or additional precautions would be greatly appreciated.)

To retract the spring, we will use a winching mechanism. However, the motor used will have to disconnect from the winch so the mechanism can fire. Does anyone have any suggestions on how to accomplish this? One idea was to use a shifting gearbox with a speed missing, but as we have used all of the CIM motors in the drivetrain, there are none available for use in, say, an AndyMark shifter. We do not have the capability to make our own gearbox. Does anyone know a way to connect a different motor to a shifting gearbox, any other suggestions on how to disconnect a motor, or a suggestion for a winch design where this wouldn't be required?

Thanks!