ENGR 111 Archery Stand Project
Team Member: Vita, Ropah, Dara
Abstract
Summarizing your work (150 words) and a single, representative photo for the project
Our archery stand aims to help those with physical limitations use a bow without having to support the weight of one. From communicating with our community partner Madi, our goal was to help archers with disabilities participate in by designing to their needs. This design aims to support the archer by putting the weight of the bow on the stand, suspending it so the archer can focus their strength into pulling the string back and shooting. We constructed our prototype using two Razor scooters for their easy height adjustability at the hand grip (36in. minimum, 48in. maximum) combined with sawing in the machine shop, resulting in a prototype which can be maneuvered from the top and bottom. The clamp is able to rotate 360 degrees, allowing the archer to adjust for the perfect shot. This design is suited for archers with limited strength or ability, as the bow can be shot with only one hand!
Problem statement
Including information about your community partner(s)
According to our community partner Madi, who is an archery teacher for children with disabilities, most of the existing bows are for teenagers and adults but not suitable for young children due to their difference in strength. Therefore, there is a need to develop a stable archery stand for children so that they can shoot the arrow without using falling back.
Design specifications
The design specifications you developed and reasons for them
Our design includes three main parts:
- The wooden base
We made the wooden base 14 x16 inches in a rectangular shape. The area is much larger than our initial prototype, which was 8 x 14 inches. We increased the size of the base in order to make the system more stable for the user– the base requires someone to stand on it to counteract the force of the shot, and so the base needed to be large enough to stand on. Besides, we removed the four wheels at the bottom of the wooden base after discussing with professor Amy and our community partner Madi because this would increase the stability of the wooden base and help it fits better to the ground.
- The supporting tubes
We designed our supporting tubes to be adjustable in height (36 inches minimum and 48 inches maximum). There is one part of a deconstructed scooter at the top, whose height is adjustable, and there is another part of the same size at the bottom. In the middle there is a steel tube that connects the top and bottom tubes to make the height suitable for young children (our target group). We design the tubes to be adjustable because different children can have different height perfect for shooting arrows, and in this case they don’t have to change their body positions to fit with the archery stand.
- The clamp
For our clamp, we chose to use a Rhino Grip because it holds the bow tighter and firmer than other types of clamps. The Rhino Grip is specifically designed for guns, bows, and other devices that need adjustability and stability, so it was a near perfect match– we just had to thicken the “fingers” of the clamp so the bow couldn’t move around too much. The position of this clamp is ¾ up the pole part of our stand. The poles are adjustable to the height of the archer, and the clamp can give even more accommodation by being totally rotatable at 360º.
Review of design concepts
A brief review of the design concepts you considered and the reasons why you selected your final design
[Reverse Engineering]
We took part of the scooter to be the tubes/pole that has the ability to adjust in height. Then we identify the components within the system of archery stand and their interrelationships to create representations of the system in the form more applicable for children (our target users).
[Torque]
Torque = Force · displacement
To maintain the stableness of the entire archery system, we calculated the specific position of the tubes and the clamp in relation to the wooden base. So that when the archer imposes a force on the bow, the archery stand would not fall or tilt.
Description of design
A detailed description of your design, including reasons for your design decisions. Include pictures, drawings, and calculations as needed to fully describe your design such that an outside party could both fully operate your product and create replicas. An appendix with an instruction manual is appropriate. Note that making a document that allows for full replication is exceedingly difficult and takes great care to do so.
Clamp: we decided to use one simple clamp with great strength in holding the bow because this would simplify the process, preventing too many moving parts. To increase the friction and stability of the clamp, we tighten each hand of the clamp with plastic bars and paper glue.
Tube Placement: we decided to position the tube/pole at the front edge (far from center) of the wooden base. We chose this because it would entail someone standing on the wood, near the other edge, to counter the force from the shot, ensuring overall stability.
Methodologies and results
Methodologies and results of tests you performed in designing and refining your prototype
We started off our methodological journey with researching the physics of archery. We learned about force and how the arrow is actually released by the force of the bow. After this initial step, we met with our community partner to ask more questions about what specifically she needed from a prototype. We gathered these notes and participated in a brainstorming session, one of the many times we would do this, and did rapid ideation.
After our first prototype, we did a feedback session with Amy, and revised our ideas! By the time we had developed our first full working prototype and met with Madi, she gave us an idea of what parts were needed and what parts we could do without. It was a real practice of what is necessary. We removed the wheels, and made sure we accommodated Madi’s ideal minimum and maximum heights.
When it came time to fully test out our prototype in the KSC, trial and error reared its head, and we realized our clamps were not strong enough, nor was our base stable enough. We could not even shoot an arrow. We read up on what clamps and mechanisms other people used in similar situations, making sure our research was sound before investing in a sturdy clamp or new parts. Finally, taking Madi’s feedback into consideration, we developed our current final prototype with two scooters, a piece of pipe, and a Rhino clamp. Therefore, brainstorming, feedback, and trial and error were our main methodological assets during our process.
Did we meet the specifications
Discuss the extent to which your final design meets the design specifications, and if there are shortfalls, indicate how these might be addressed in the future.
Our final design does meet the design specifications. The base is very stable, and for every archer regardless of height, they all will have the ability to shoot with desired accuracy. After many tests at different heights, the stand securely holds the bow and allows a proper aim. The Rhino Clamp definitely gave us the feature of full rotatability, which is essential for the user.
However, this prototype can be improved in its balancing of torque on the rotating side because when we tested it in KSC a person needed to hold the tube so make sure that the archery stand did not fall over when someone is shooting. This shortfall would have been avoided if we tightened the proper screws to their full capacity before shooting to prevent that rotation. Given this, after the demonstration, we did tighten the screw a little, so we hope this resolves the problem! If not, it would only take a few seconds and a screwdriver to solve.
How your design has been received
How your design has been received by your community partner, what follow up is needed, and how that will be achieved: these plans should be explicitly discussed with Prof. Banzaert prior to writing the final report
Our design was well received by our community partner Madi. She got to see our design when we tested it in KSC during our last class period. Madi was satisfied with the strength of the stand and the overall design which allowed for height adjustment and full range of motion. She also pointed out how it was so easily transportable, given it’s literally a pole attached to wood. It’s very much usable once you set it on the ground, and does not require set-up. One area of growth that Madi pointed out is the lack of flexibility of the clamp when it comes to ambidextrous rotation. This is important for when different archers use the bow, they will need to change the position of the stand, unclamp the Rhino Grip, reclamp it, and then shoot. In the future we might incorporate a better design for the rational flexibility to meet this need, although since the Rhino Grip is unmoving, we do not see a quick-fix for the issue. Overall, our community partner seemed very excited with our product and we are all so happy to see that our work will benefit others!