A spring based catapult is at rest vertically. It gets pulled back to a horizontal position to arm, which activates a self-ball loader. On firing, it springs forward and launches ball.
The arming mechanism will be motor based but the issue I can't get past is the motor on the launch portion. My ideas include:
- Bike chain and gearing.
- Some sort of clutch on motor that releases on launch.
- Some sort of indexed cog off the motor that pushes the catapult to the horizontal but at that point the catapult releases back forward and the cog spins around again to pick up.
I've considered stepper motors but I'd like to keep it as simple as possible.
Further Details –
The spring in question is actually a car engine belt tensioner. So we are talking roughly maybe 30 foot lbs to compress. It is bolted to a 3 ton jack stand which is bolted to a frame.
The frame right now is roughly 30 in long, the catapult arm length is still in question due to distance requirements of projectile.
I am considering making the arm length adjustable.
The ball feed mechanism is basically PVC with spring gate that gets compressed when arm is pulled down.
Projectiles are baseballs, softballs. snowballs etc….
I am currently stuck on finding the right motor. So far I've ripped apart a belt sander and an Oreck vacuum looking for answers, with no luck. I am also considering winch methodology or possibly chain hoist theory. Thanks for the responses.
Best Answer
You could probably do the whole thing with one motor and a solenoid using the same principle as a car's start motor / starter solenoid. Basically, mount a gear to the main arm. The solenoid would push the drive gear (which is attached to the motor with a worm gear) against the main arm gear to lower it down. To launch, disengage the solenoid.
Note that you can make your own simple solenoid with a simple electromagnet / spring in opposition.
I haven't thought a whole lot about the loading mechanism... Some more information on the size of the apparatus would be helpful.