Intro: Wheelchair Rear Bumper
One day, I was watching a caregiver attempting to drive my wheelchair. BANG! BOOM! The wheelchair first slammed into one of our counters, and next into a wall. The chair was already on the slowest speed, so fortunately, the damage was minor, but it got me thinking about the need for bumpers on a wheelchair. For instructions on making bumpers for the front of a wheelchair, check out my instructable Wild Wheelchair footrest pads and bumper at https://www.instructables.com/id/Wild-Wheelchair-footrest-pads-and-bumper/ . This instructable is on how to make a rear- wheelchair bumper that not only looks cool, but is functional too.
1 Aluminum Bar approximately 3 feet long and 2 ½ inches wide. (available at most hardware stores in the metal sheet area)
2 large half threaded bolts
2 small coil springs (also available in most hardware stores)
2 scrap wood blocks
Step 1: Step 1: Is This Right for My Wheelchair?
This instructable is designed around my particular model of wheelchair which is an Invacare model. To make this work with your wheelchair may require some modifications. Also, be sure to check the warrenty on you wheelchair before making any modifications. This instructable will require drilling into your wheelchair which could void the warrenty of your wheelchair. Before making any modifications, make sure that all electrical connections are away from where you will be working. It should also be noted that this bumper will have to be removed when it comes time to replace the battery in your wheelchair.
For my particular wheelchair, the frame of the chair consist of two hollow metal pipes. Ordinarily, the ends of these metal pipes are covered by a plastic cap. For this project, the caps were removed and careful measurements taken of the size of this hollow metal pipe. On my chair, the pipe was large enough that two blocks of wood could be inserted into the frame on both the right and left side of the chair without interfering with any electronics.
The wood blocks have to fit tightly into the frame of the wheelchair as this will be the support for holding the bumper on the rear of the wheelchair. If you do not have a place to insert wood blocks, you may have to find another way to mount your bumper to the chair. The other principals for the bumper you may still find useful.
For my chair, the two scrap pieces of wood block, approximately 4 inches long and 2 inches wide where cut and sanded to fit tightly into the frame of the wheelchair. I painted these to match the color of my chair, though this is optional as not much of the blocks is visible. Measurements were then carefully taken to measure the distance between the center of these blocks of wood from the right to left-hand side of the chair. This will be the distance between the two drill holes you will need in your bumper. Next, measurements were taken of how long the bumper should be. For me, I didn't want the bumper to be longer than the width of my chair.
Step 2: Step 2: the Bumper
Using a long narrow bar of aluminum bought from a hardware store, a measurement was made of the length I wanted the bar to be, plus some over-hang of about 2 inches for primarily decorative purposes. The overhang is the part of the bar that will be bent inward giving the bar that distinctive bumper-like look of that of an automobile. So, if your wheelchair is 32 inches wide, and you want the bumper to be that long, add an additional four inches to make the bar be 36 inches long. Cut off the excess of the bar.
Next, mark with marking pen the rounded corners of the overhang. Cut and file these corners with a saw and metal file. Aluminum is fairly soft, but you will have to work hard to cut this. It may be easiest to cut off the corners, then use a file to round them. Be very careful to make sure there are no sharp points as these could be dangerous if someone is clipped by the bumper. Be sure to use all safety precautions when cutting metal, including protective eye-wear and gloves. Be sure to secure the bar tightly using clamps before cutting.
Mark the area where you will be bending the metal. You will want to make your marks on the inside of the bumper where it won't be visible, or make your marks in pencil or some marker that can be washed off. Mark also where you need to drill holes for attaching the bumper to the wheelchair. This will be the center of each of the wooden blocks that are to be mounted into the frame of the wheelchair. Drill a hole in each of these locations large enough that your large bolt can slide easily through this up to the head of the bolt.
Bend each end of the aluminum bar in the marked locations. Aluminum is relatively soft, so you may be able to do this by hand if you are very strong by clamping one end to a solid surface and pushing down on the over-hang, or by carefully hitting it with a hammer until it is shaped as you wish.
Step 3: Step 3: the Parts
The first step is to drill a hole in the center of your woodblock. This is where the bolt will be tightly screwed. You'll have to pre-drill this hole before screwing the wood into the block. Insert the block of wood into the wheelchair's frame. Again, be sure to check that you are clear of any electronics or mechanical things that might interfere with the wheelchair's operation. To secure the woodblock, you will need to drill a single hole in the top of the frame of the wheelchair, and secure the block with a screw that goes through the chairs frame and into the woodblock. Wheelchair frames are very strong... be sure to use a very good drill to make this hole. Screw the woodblock so that it is firmly positioned into the frame of the chair.
Step 4: Step 4: Mounting
Put your large bolts through the aluminum bumper, then position a coil spring on the back of the bumper before screwing the bolt to the wood blocks. The spring holds the bumper against the head of the bolt, and lets the bumper move some if it encounters an obstacle.
Once the bumper is bolted with the spring to the chair, you are done!
Step 5: Safety
This bumper primarily acts as a warning when your backing into something, and can protect some of the wheelchair from hitting walls and furniture. If you back into someone, because the bumper is spring cushioned, it gives whomever your bumping into a chance to warn you that you are running into them. Usually, you can hear the bumper hitting something, and act to prevent causing what your backing into more damage. However, it is more a decorative item than being as functional as something like a car bumper. The bolts themselves do not move, and therefore can still scratch and tear into walls and furniture. The aluminum is fairly soft, so it may bend if you run into something at a high speed. In other words... don't try using your wheelchair as a bumper car!