Happy Meals Spider Shooter
This project entailed creating a low-cost, mass-manufacturable (by injection molding), and appropriate toy that could be used for a McDonald's happy meal. We created a spider shooter that consisted of an arm band with a rail on top for the spider to slide onto snug. When the rear legs of the spider are squeezed to a certain point, the fingers will slip and the potential energy build up will transfer to kinetic energy and launch the spider projectile. All design was done on SolidWorks and the final cost was determined to be $0.32 per piece when injection molded. For the prototype shown on this page, the product was 3D printed with ABS plastic.
Arm Band
The arm band was designed with a radius of 2.08 inches so that it could fit comfortably on the wrist of the average 6-10 year old boy, which was determined to be our target market. It has a rail on top for the spider projectile to slide onto. The whole piece costs $0.19 per part, making it the most expensive piece.
Adapter
This is the adapter piece. Its cavity on the inside allows it to slide onto the rail of the armband loose enough so that it can shoot with minimal friction but tight enough so that the arm does not have to be perfectly balanced to keep the spider on its rails. Many iterations of tolerancing the cavity was carried out before obtaining the optimal dimensions. Its curved sides were created to keep the walls structurally sound while still ensuring low mass. This piece costs $0.02 making it the most inexpensive piece.
Spider Projectile
This is the spider projectile. It has a divot in the bottom for the adapter to snap in place underneath it. It also has a hole for a string to connect the piece to the arm band so it is not easily misplaced/lost by children. Furthermore, the rear legs are spaced 0.96 inches apart from the end and have a maximum width of 0.1 inches to launch with a sufficient velocity to travel in a straight line for the entire 12 inch length of the string but not too great of a velocity to where it becomes a hazard. This piece costs $0.03.
Final Product
This is the final product after 3D printing and assembling the three pieces designed on the SolidWorks CAD software. All of the pieces were filleted 0.01 inch to eliminate any jagged edges that could pose a danger to the customer.
