Introduction: Knex Pull-back Car, Ball Machine Element
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: https://youtu.be/-u3Mi7ozmv0?t=25
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.