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Unread 26-10-2016, 21:19
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GeeTwo GeeTwo is offline
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Re: pneumatic catapults

Quote:
Originally Posted by Joey1939 View Post
You don't want to leave the retracting side empty because then you will get stuff inside the piston. We found a really nice filter that screwed into the piston.

Our piston setup was weighted weird because the pistons were backwards (so that extend launched the catapult) and gravity was our return.
That seems reasonable. As a simple solution, a bit of cheesecloth and a couple of tie-wraps might also serve to keep swarf, dust, and such out.

Gravity return is perfectly usual for this sort of launcher. Even so, you will want to reduce the weight of the ball carriage to a minimum so that most of the energy goes into the projectile rather than in beating the carriage against its stop. This means mounting the cylinder body to the robot and mounting the piston shaft to the ball carriage. This sort of mount will also require less "loose" tubing.

Edit: And hoping that the use of piston to refer specifically to the portion of a linear pneumatic actuator which moves relative to the cylinder and fittings doesn't draw IndySam's wrath...
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Last edited by GeeTwo : 26-10-2016 at 21:27.
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