Wheelchair Shooting Apparatus

Overview

The wheelchair shooting apparatus is a tool to help disabled contestants shoot a shotgun. The clientele that will be using our apparatus normally suffer from TBI or traumatic brain injury. Our goals are to provide a functional shooting apparatus for use by those with limited bodily function. The apparatus will be used for shooting skeet, so it must be able to secure a shotgun and move in a path suitable for shooting clays. It is an expressed goal to have the motion feel as natural as possible while remaining assistive. This is mainly achieved with the assistance of a good base along with a shock system that supports the weight of the gun and carries the smooth motion.

The apparatus will be made to be both stand alone and mountable to the motorized wheelchair, the trackchair. The apparatus will need to be somewhat compact and lightweight for ease of transport. It needs to be relatively simple, so as to be reliable under hard use, and have parts that can be easily replaced. That being noted, the use of custom parts should be limited as much as is possible, with off the shelf parts being preferred for ease of replication. The main parts that were custom made on the design were the pivot points on the Caldwell base and the shock mounts to support the weight of the gun. In addition, a trigger mechanism for those with the ability to either push or pull (though who cannot physically pull the trigger) will be made (custom) so that the end user may have as much autonomy in skeet shooting as possible.

During our design stage, we considered many different options. Some of these concepts included a 180 degree rail mounting system onto the wheelchair, an “anti-aircraft” gun design, and our current design. Ease of use, and cost really drove us to use our current design. We discovered the other designs would not only be hard on the contestant, but on us to create. The current design we are using also was the design that was best suited for this challenge. Our design is based off another product, the Caldwell Deadshot Treepod. We mostly added to this product, and catered it further to our clientele. Most of our analysis that was done, was physical. This minimized the need for FEA analysis and calculations.

To design around the Caldwell Deadshot Treepod, we began with a base system that allows the design to be stand alone along with a system that attaches to track chairs to allow users to use this product in a variety of locations. After having the base design complete, the next step was to modify the Caldwell to support the smooth motion and natural feel that the client was looking to achieve. In order to do this, the pivot point of the system was transitioned into the shoulder area to create a natural feeling motion.

Once this was complete, the shock was added to enable the weight of the gun to be supported by the Caldwell rather than the Challenger. Selecting the shock was difficult because the strength of the shock impacts the fluid motion of the design. If the shock is too strong, the gun will lift up and the challenger will need to force it down whereas if it is too weak the challenger still needs to support the gun to some extent. By finding a shock that suits the weight of the gun, the ease of motion stands out since the gun now moves up and down with little effort.

To allow for a wider range of guns, a ballast system has been implemented to keep the proper balance within the system. The final design that was added to the Caldwell was a system of straps to limit the movement of the device for safety concerns. This incorporates a safety system widening the usability of the device. The improvements made a lot of difference in how well this product worked with the Challengers and how they enjoyed the experience of using the system.