At the School of Sustainable Design Engineering at The University of Prince Edward Island in PEI, Canada, our Dynamics 234 class has been developing snow-throwers to learn the theory and calculations involved with dynamics. This project has also taught us the steps for the design process which will be crucial in future years of engineering. My group consisted of three students; Chamara Dilum Kuruppu, Reagan Mills, and myself, Ryan Legault. Our goal was to develop a snow-thrower that is long range and mobile, while also being a shield to defend against other snow-throwers. The goal of the project was to develop a launcher or defending structure that would launch or defend snowballs effectively while using re-used material from previous projects.
Step 1: Materials List
Our materials list for our snow-thrower is as follows:
.Two side boards (9"x1/2"x12") made of laminated wood
.Two base boards (36"x1/2"x8") made of laminated wood
.Sides of frame (4"x1/2"x24")
.Base of frame (36"x1/2"x4")
.Potato sack (to cover wooden frame for protection)
.Big rubber bands (x16)
.Screws (1.5" and 1/2'')
.Plastic cup (snowball holder)
.Rubber tubbing (handles)
Step 2: Cutting Side Boards, Base Boards and Wooden Frame
To start building our snow-thrower, our first step was to cut the side boards, base boards and wooden frame to size. Our two side boards were cut into 9"x1/2"x12" pieces using a ban saw. The two base boards were also cut using a ban saw into 36"x1/2"x8" pieces. The wooden frame was composed of two pieces measuring 4"x1/2"x24" and the base of the frame was cut to measure 36"x1/2"x4". The wooden frame pieces were cut using a jig saw.
Step 3: Attaching the Side Boards and Base Boards
The second step in creating our snow-thrower was to attach the side boards to the base boards. To do this, we put the base boards on both sides of the side boards with a four inch gap to be able to able insert the wooden frame. The base boards were then screwed in to the side boards using 4 screws (1.5") on each side to ensure it was secure.
Step 4: Attach Wooden Frame Together and Attach to Base Boards
The third step in assembling our launcher was to attach the wooden frame together, followed by attaching it to the frame. The wooden frame was assembled together using 1'' nails in each corner (four on each side). Also, on each of the side of the wooden frame, a hole was drilled to insert a zip tie to ensure the bottom of the frame did not come undone. The next part was to attach the entire frame to the base boards using 1.5" screws (four on each side) to ensure it was fastened tightly.
Step 5: Drill Holes in the Side Boards and Frame
The fourth step in creating our snow-thrower was to drill 1/4" holes in the side boards and frame. The holes in the side boards were drilled 1" from the top and 1'' from the side. These holes were drilled to be able to attach the rubber bands in the future. For the frame, two holes were drilled in each of the sides of the frame to later on attach at the potato with zip ties. These holes were drilled 4" from the top and bottom and 1'' from the inner side.
Step 6: Attach Potato Sack to Frame
To attach the potato sack (burlap sack) to the frame, zip ties were inserted threw the holes that were drilled and fastened tightly to make sure it did not come loose. In total, six zip ties were used to attach the sack. Duck tape was also used around the outer sides to tape the hanging pieces of potato sack to the frame.
Step 7: Create Launcher
To begin the fabrication of our launcher, a plastic cup was used to hold the snowball. Four 1/4'' holes were drilled in all four sides of the cup to attach a square shape of zip ties to it (seen in pictures above). Two more holes were then drilled in the middle of the cup to attach a zip tie handle. The next part of this step was to create the rubber band structure. To start this, two rubber bands (4 different times) were used to attach to two other rubber bands by a zip tie which was then fastened to the square zip ties. This was done four times to have a stable structure in the middle.
Step 8: Attach Launcher to Side Boards
To attach the launcher structure to the side boards, the two hole previously drilled were used to wrap rubber bands threw them to secure them to the structure. This technique worked very well because the plastic cup sat perfectly in the middle with equal tension on all four corner bands.
Step 9: Attach Handles to Side Boards
The final step in creating our snow-thrower to was attach handles to the side boards to allow us to be mobile when in battle. Rubber tubing was used for the handles and was attached to the side boards by 1/2" screws that were drilled 1'' from the top of the boards and directly above the base board.
Step 10: Final Product and Operation
The final product of our snow-thrower is shown above. After many tests using duck tape balls weighing approximately 105g (actual snowball is approximately 191g), our launcher was successful and was able to launch the duck tape balls an average of 80ft (roughly 24m).
The operation of our device is fairly simple. First off, two group members must hold the the device using the handles to ensure the device is steady. The next step to the load the launcher by placing a snowball in the plastic cup, followed by pulling the launcher back using the zip tie handle and ultimately releasing it. From our testing, our group discovered that by pulling the launcher back approximately a 12'' and at an angle of 30 degrees, the ball would launch its maximum distance (approximately 95ft) with a duck tape ball.