Saturday, May 29, 2010

Automatic Touch-Sensitive Reversing Transmission

This is a proof of concept for a 2-setting automatic K'nex transmission. This mechanism is not intended for use in any future project, I simply had the idea and wanted to see if it would work. The wheel on top of the mechanism spins continually in one direction until its movement is interrupted. The machine detects the rotational force applied on the axle and automatically switches gears, reversing the direction of the wheel to avoid stress on the motor.

This machine was designed and built in about 4 hours from nearly 500 pieces and 33 gears.

Video of the mechanism in action:

Close-ups of the switching mechanism:

The red gear in the upper right slides along the length of the red rods depending on the tension of the chain. This gear rides on a cart which triggers the transmission when it reaches a certain height. There are 2 of these tension mechanisms in the device, one for each direction of rotation.

Sunday, May 9, 2010

K'nex Dome

School's out, so I am able to begin building massive outdoor structures again. Here is the first of what I hope will be many.

This K'nex dome spans over 14 feet and is almost 6 feet high at its center. Each leg is 10 feet long, but only 3 inches thick. I designed this dome to test a modification of the k'nex arch I used in The Labyrinth. The dome was built in 10 hours by Austin Granger and Sam Ihlenfeldt and uses over 5,500 pieces.

Under Construction

Testing the design strength with 4 legs

All 8 legs in place

Center of the dome

Close up of one of the legs