Introduction: Knex Pull-back Car, Ball Machine Element

About: I'm into knex ball machine stuff. My favourite parts are lift/element hybrids, probably because I tried building a perpetual ball machine. It didn't work, of course. All my knex stuff is creative common, and …

This element is a lever and a car. The lever engages a motor which pulls the car to the top of a ramp. Then the ball gets on the car and drives back down the ramp.

This was used in my most recent ball machine:

Step 1: Frame

Step 2: Lever Axel

Step 3: Combining Steps

Step 4: Ball Arm

This is where the ball waits while the car is getting pulled back.

Step 5: Lever Counterweight

Step 6: Motor Axel

Step 7: Engaging Gear

This gear will be attached to the lever. This is what engages the motor to the rest of the mechanism.

Step 8: Further Frame

This holds the lever so it doesn't tilt too far backwards.

Step 9: Disengaging Gears

When the lower gear has does 3/4 of a revolution, it will force the lever to tilt back. This will disengage the motor, release the ball, and let the car go down the ramp.

Step 10: Even Further Frame

This stops the Disengaging Gears from rotating too far backwards.

Step 11: Reel

This is what pulls the car up the ramp.

Step 12: ​Final Frame

This helps the ball land properly on the car.

Step 13: The Car

Once you're done, tie this to the Reel, and build a track for the car to go on.