Overview

International 1/4 Scale Tractor Student Design Competition

• ASABE Hosts the 1/4 Scale Tractor Competition annually in Peoria, IL.
• About 30 collegiate student teams participate in the event
• Performance events include tractor pulls, a maneuverability course, and a durability course.
• A panel of industry experts judge each tractor design for innovation, manufacturability, serviceability, safety, sound level, and ergonomics.
• Each team also submits a written design report and must present their design to a panel of experts playing the role of a corporate management team.
• Students gain practical experience in the design of drive train systems, tractor performance, manufacturing processes, analysis of tractive forces, weight transfer and strength of materials.
• The top 5 winning teams receive cash awards.

For more information, visit ASABE.org

The short video above is from an early iteration of our design. It does a good job of showing the concept behind the design and the way the shift lever arms (orange, green and blue levers) move together inside of the cam plate.

The image above shows the cam plate with the individual grooves that shift each gear lever forward and backward 15 degrees as the plate moves. Each position of the gear levers select 1 gear on the 6 speed transmission.

The two images above show a further iteration of our design. A spring will be inserted into the slots at the end of the lever arms. The spring will compress to ensure that the transmission actually goes into gear in case the teeth did not initially align. The colored brackets are locked to the gear shaft and the gray levers are free to move and compress the spring against the colored brackets.

The final design of the shifting levers allows us to fabricate the assembly out of only 2 different parts. The 2 outer levers are free to rotate about their respective gear shift shafts, while the center lever (seen on the left side) is fixed to the shaft and moved via the transmission of force through a spring.

The cam plate assembly consists of two parts, the backing made from 16 gauge steel (in black), and the 3-D printed cam plate itself (right). The 3-D printed cam plate allows us to make changes to the exact path of the cam followers without having to get the entire cam plate fabricated from steel again. An additional benefit includes reduced friction between the cam follower and the plastic cam plate. Also included in the image is the plate mount, which supports the cam plate and the linear servo that moves it.