Robotics Education & Competition Foundation
Online Challenges

Adjustable Locking Hinge

1

ThomasMilne13
Entry ID #: 7546
Created: Sat, Jan 11, 2020 11:17 PM


Team 929H - Hereford Zone Robotics (High School) - Adjustable Hinge Introduction and use: With no expansion limit and an ever-growing list of deploys to make, an adjustable hinge device is needed more than ever. For our team, we need to create a new hinge, stop, and lock for each of our deploying mechanisms. That includes deploys for our 3-stage tray, fold out intakes, and anti-tip wheels. This process can be extremely tedious considering the hinges currently sold are bulky and lack customization. Other techniques can involve complex system which take time to design and may be too weak or too heavy for load-bearing applications such as our 2nd to 3rd stage tray deploy. With a strong and lightweight adjustable hinge however, many deploys can be constructed with ease. This product is especially crucial for incoming teams just beginning their journey in Vex Robotics, who may not be able to design their own deploy. Without any deploys the number of cubes that can be stacked or towered by a team can be severely limited by the initial 18 x 18 x 18-inch size constraint. Therefore, this product could be used to elevate their design exponentially. Use of software and design: To design this innovative adjustable hinge, I used Autodesk Inventor 2019. Since we needed this new part to be customizable and easy to manufacture, I went with a 3-piece design that can be combined to lock in place at 45-degree intervals up to 315 degrees. I started by creating a base plate with two mounting holes on either side of a circular extrusion. On this center circle I could create a hole for the free rotating plate and clamp plate to be mounted. Then I used the pattern tool to quickly create 8 holes around the center where the screw stop could be placed. The next part I designed was a middle plate that used a similar shape to the base plate, but without the center circle extrusion. I added rectangular cutouts to the first hole from the center so that the plate could rotate until the screw stop fit snuggly into the hole at the intended angle. Next, I created a new part that would be used to clamp these two plates together. This clamp used the same cylindrical geometry as the center extrusion from the base plate to ensure its compatibility with the other two plates. Throughout the plates and clamp I created holes that would allow the user to screw everything together, placing the screws in certain holes to customize the angle of rotation. Then I was able to assembly these pieces together with screws and lock nuts to begin visualizing the motion of the 3 pieces together. With various constraints and a motion contact set, I could ensure everything worked as intended. However, I discovered that the middle plate needed circular cutouts that matched its rotation, rather than the rectangular cutouts initially used. To do this I created circles centered at the axis of rotation and tangent to the outer and inner edges of the first hole. After removing this cutout from the middle plate and again testing the motion in the full assembly, I realized it couldn’t rotate a full 180-degrees. In order to combat this, I created an additional part that was half the length as the original middle plate. This half-length plate could be used to achieve rotations greater than 180 degrees but would result in a weaker connection to the structural piece as it also had half the connection points (2 instead of 4). With these 4 pieces alone, teams can create and customize their deploys for almost any scenario. Conclusion: As an aspiring engineer, using 3D CAD software has allowed me to communicate a design or plan in my head to my teammates, alliance partners, judges, or stakeholders. Being able to visualize a full design helps for many reasons. First off, you can see how parts come together in a way you may not have been able to in your head, it gives you a glimpse at how they would work together in real life. This allows for you to realize mistakes before dedicating too much time or resources in to making and testing that design. It also allows for quick modifications to a design, much quicker than modifying a physical prototype. Finally, it allows for an easy and quick way to create a simple mock up of that design in real life: just 3D print it. There are also a couple benefits to using CAD as part of robotics. Since we spend a lot of time putting together assorted designs, without knowing how they may work when we're done, it is often helpful to CAD the design to see how it may, or may not, come together before beginning construction. Prototyping with CAD also allows for you to create a bill of materials. This means you will know if you have everything you need to complete your build or not, and if you don’t, you know exactly what you need to purchase or ask a mentor for. If all else fails and you can’t get everything you need, you can always quickly redesign your CAD, without having to scrap a build you just ran out of parts for. All in all, I learned that CAD may be frustrating or time consuming in the beginning, but its continued use sure is worth the effort in the end.