In the sport of snowmobiling, a rider is susceptible to inadvertently falling off the vehicle. A snowmobile carrying momentum without a rider to control it can significantly increase the chance of an accident. To prevent damage to a snowmobile during an unplanned dismount, an emergency braking system needs to immobilize the vehicle. Snow Control’s goal is to develop a product that initiates a process to bring the vehicle to a stop. The product comprises of four main functions: a method to engage the system, transfer a signal to mechanical or electrical energy, use the energy to engage brake movement, and preform total system reset. A tether switch will engage an electrical system that will activate a pneumatic clamp and brake pad similar to a brake caliper on a rotor disk. The secondary pneumatic clamp bolts to the stock caliper of the snowmobile by a bracket that is supplied with hardware. Reinserting the tether switch resets the system and releases the secondary brake.
Proof of Concept
Snow Control’s Proof of Concept (PoC) will accurately test a large portion of the emergency snowmobile dismount braking system design. The purpose of this PoC is to take a series of theories and calculations and apply them in a physical test. This will consist of testing the PA-14 Mini Linear Actuator with the HH200 Series Mechanical Disk Brake caliper to prove the systems can cooperate flawlessly together while acting on the stock brake rotor of the snowmobile. To prove this, two mechanical devices must be mounted together using a machined bracket. The bracket (1.1.0), will first be 3D printed using ABS plastic on a Stratasys Dimension printer to test fitment, which will allow tolerances of ± 0.1 inch. When proper fitment is achieved, the bracket will be milled using a CNC machine and a block of 6061 Aluminum and vibration polishing for the finish. Using this prototype, a series of tests will determine the effectiveness of the system using two separate criteria for failure to confirm previous braking calculations. The criteria requires a minimum braking force of 334.6 lb-f and a minimum lever force of 225.6 lb-f. Using a lift, the track of the snowmobile will be elevated to complete a stationary PoC test. The first test will be completed at a track speed of 10 MPH. If PoC passes the criteria for failure, the test will be completed again, increasing track speeds by increments of 10 MPH until 60 MPH is achieved.
Snow Control is in the processes of designing and developing a product that will be used as a secondary braking system for snowmobiles. When a rider is ejected from a snowmobile, the uncontrolled snowmobile can freely coast and potentially cause serious damage to itself and its surroundings. The goal is to stop the snowmobile quicker and this will be achieved by designing a secondary brake that is activated when the rider is thrown from the snowmobile. When there is a disconnection of the tether switch between the rider and the snowmobile, an electric signal will be sent to a linear actuator that is mounted on the frame of the snowmobile, using a bracket custom fit bracket made out of aluminum. The linear actuator will push on the lever of a secondary brake caliper that is mounted to the same bracket. The caliper will clamp down onto the stock brake rotor bringing the snowmobile track to a stop. With the addition of this after market part, the consumer would have a much better chance of their snowmobile avoiding a collision when they fall off which would save them lots of time and money when it comes to repairing the damages of a crash.
The fabrication process for this project began with taking detailed measurements of the brake system on the snowmobile that was used for testing. Once these dimensions were noted, SolidWorks was used to draft the parts that were needed for assembly. The first bracket design, shown in Fig. 1, was 3D printed so that correct and precise fitment could be verified before finalizing all measurements. The next step of the process involved applying final adjustments to the SolidWorks file, shown in Fig. 2, before the final parts were machined to specifications from a sheet of Aluminum 5052, shown in Fig. 3. These parts were then welded to create the desired bracket for the final assembly, shown in Fig 4. Wiring of the electrical system came next, which consisted of the battery being connected to the actuator with both the tether switch and reset switch, which allows for the secondary braking system to engage and reset to its original setting. The final step of the process was to connect the actuator and caliper to the bracket with their included mounting hardware to create the final prototype.
Fig. 1: 3D printed bracket made out of ABS plastic to test for fitment.
Fig. 2: SolidWorks bracket with new adjustments made from the fitment of the 3D printed bracket
Fig. 4: Welded bracket consisting of the four aluminum sections.
Testing and Results
Testing of the product consisted of the system being installed in the snowmobile. The snowmobile was then brought up to a speed of 60 miles an hour and then the system was engaged. In order for the product to pass the test, it needed to successfully stop the track every time that it was engaged. Our team tested the product throughout a day of riding around various snow conditions and types of terrain and found that it successfully stopped the track each time it was engaged. This drastically reduced the stopping distance of the snowmobile without a rider which was the problem that we were attempting to solve. This will make things easier for the user because a runaway snowmobile will go a lot shorter distance and will reduce, if not eliminate the damage to itself and other objects. No substantial amount of other user input was collected; however, they should be very pleased with the system as it successfully does what it was designed to do. In terms of test data, the final test was simply pass or fail with no failed attempts present in testing. Further testing will need to be conducted before the product is market ready, however, the initial tests were very hopeful in terms of a flawless performance of the product.
Meet the Team
Maia will be graduating this spring with a degree in Mechanical Engineering and a minor in Community Health Sciences. Her diverse education gives her a solid knowledge in a variety of subjects. She has worked as an intern at Sangamo Biosciences in California, and is currently employed at UNR’s Innevation Center, where she assists students and members in the prototyping stage of their product development. This has given Maia experience working with production tools, such as 3D printers, laser cutters, soldering irons, etc.
Jack Mokler graduated high school in the top 5% of his class and received recognition by the National Honors Society. Originating from Mammoth Lakes, CA, a small ski-town in the Sierra Nevada Mountains. Then moved to Reno, NV to complete an undergraduate in Mechanical Engineering at the University of Nevada, Reno. In the near future he intends to complete an internship and apply to ME jobs across the nation. His goal is to earn a position involving materials and components applied in machinery that is involved in the aerospace industry.
Zach was born and raised in Truckee, California. After graduation, he plans on seeking out a job for a company that is contracted by the D.O.D. to build new armored vehicles or weapons systems for the military.
Born and raised in Santa Rosa, California, Jake moved to Reno to attend the University of Nevada, Reno to pursue a Bachelor of Science Degree in Mechanical Engineering. Projects in including SolidWorks modeling, finite element analysis, NXT programming, and circuit board soldering in the undergraduate program prepare Jake to graduate in spring 2017. After graduation, his professional life will lead him into the automotive industry to work for a company such as Toyota or Tesla.
From Sacramento, California, William came to the University of Nevada, Reno to receive a Bachelor of Science in the field of Mechanical Engineering. Through the years, William has achieved multiple academic achievements such as proficiency in Microsoft programs, SolidWorks modeling, and MATLAB. Through previous internships, William has worked with plastic injection molding machines and programmed multiple HAAS CNC machines to construct precision cuts in steel molds for plastic medical components. After graduation, William hopes to obtain a challenging position within the dynamically growing field of communications that will allow him to build a successful and rewarding career using engineering, problem solving, and social skills.
Snow Control would like to acknowledge our team mentor, Rory Humphrey, for his advice and input into our successful design.
Snow Control would also like to thank Jamin Parker for his knowledge and contributions on the h-bridge wiring system.