Introduction: A Relatively Simple Quick on and Off Knee Brace Modification Or
Brake When you See the Wall...
Jay Leno would get that one at a glance...
And it's Brake not break.
Things change good and bad but when things pile up on me,
I find a distraction and take a break from whatever is stressing me out.
This is Shiny my wife has RA her joints are twisting she needs a knee brace to stand up and she has them but the time it takes to put one on at three AM...
I should be thankful I have the borrowed time to spend but I must admit to being grumpy in the early morning hours woken.
Her knee has begun to bend sideways and surgery is not an option so I thought and got a few things and my welder and made her a quick release leg brace that is well padded and allows full movement of the knee in the normal direction but locks out any lateral movement. When standing the slip joint is fully inserted and provide maximum stabilization and when in a 90 like when sitting is almost fully extendedand has a tiny amount of slop built in so it becomes just a loose hold since there is less stress on the knee in that position and her feet will sit flat to the floor.
I even managed to break a sewing machine so I got a puzzle out of the deal!
I'm sure they make them and we could have gone and gotten an appointment and waited to be seen by her PrimAry then refered to a specialist then fitted and wait for it to be manufactured then delivered then set up another appointment for a final fitting and I needed it yesterday for the wife...
Looks primative but it locks the knee solid in the standing position to keep it from kicking sideways due to her RA and it is comfortable for her to wear.
Step 1: Basic Stuff I Bought Got or Had and Some Tools
A velcroed knee brace, some 3/16th square, 1/2 inch by 1/8 flat steel, and some 1/8 by 7/8 steel, the latter just happened to be left over heavy duty hurricane straps from building the house so I used acid to wash off the zinc but you could do the same with a grinder and I in fact did up until the time I wash finishing it up.
Some 1 1/2 wide webbing, carpet thread and a few round headed 1/8 inch nuts and bolts with fender washers grade five about an inch long but they get cut flush and I probobly could have used a 3/4 inch long one.
Add some left over spray paint and a mig welder which yes I know is not in everyones garage, a drill and 3/16 drill bit, various clamps and vices (smoking is bad for you).
The first thing I did was test fit the brace as it came out of the box and I used masking tape to mark where the velcro strap ended when it was fairly snug on her.
Two straps to pieces of tape.
Then I got a flexible measuring tape the ones they use to sew are perfect I should add that to the list but if you read this far.
Anyways I measured the distance from end to end of the brace with her leg as straight as it can go, then flexed her knee to a 90 and using the tape and starting at the center I measured out half the length of the brace straight and found the brace now was an inch and a half longer across the top where the steel would be secured so not only did I need a hinge it needed to be a slide.
At this point I should have taken a moment to doodle a sketch but that always seems to take so long but I did take the time to make a template of the curve of her leg both above and below the knee so I could curve some steel for reasons of securement...
I tend to just plow ahead blindly and built this house from / or / and got the permits with two notebook sized sketches of the floor plans and a cross section of a footer.
After it was all framed I made some drawing but I must have been really bored.
Step 2: Sorry to Throw a Curve.
Anyways, yes curves I had thought the slide needed to be a curve and with one pivot point yes that would have worked but since two are better than one I had to.
I basically made a channel for the 1/2 wide strip to slide in and out of using the 3/16th inch stock as side of a rectangular tube with the 7/8 inch strip being the top and bottom. This left a loose fit over about 2 inches of travel and was surprisingly smooth for a rush job when moved in an arc but since force really tends to go in straight lines, grabbing the two pivot points and attempting to pull them apart caused the arc to bind and log like a Chinese finger puzzle.
This might be handy to remember for something but benefit from my perfect hindsight make it straight to start with.
I turned it red with fire and hammered it flat real quick.
You do want to fashion two feet to attach the hinges to the brace. I made them from 2 pieces just under 4 inches long of the 7/8 wide stuff and 6 pieces about 3 inches long of the 1/2 wide strip, and used a simple piece of heavy pipe with an arc cut from it as a curved anvil and shaped them to match the template I had made of the wife's leg.
Use a ball peen hammer or one with a rounded head and light taps. The wide one is the bottom and should be dead on if possible, and the 1/2 inch wide ones I made with a slightly tighter radius since this is used to turn the wide strip into a basic truss and allow for a very solid point to weld to the hinge but spread out enough so as not to damage the wife and gave me room to secure it to the webbing with 3 bolts on each side and fender washers. Use grade 5's at least. Attaching the webbing to a brace is simple sewing but the webbing needs to be securely attached to the steel since it's doing the work.
Hopefully I'll remember to mention the need to drill three holes in the feet since I forgot in the past but unless you read this backwards it awaits in your near future
Anyways I again test fitted the brace to the wife and held the 3 1/2 inch hinges I had fished together over the brace. You need to essentially build an bridge over the knee to prevent it from hitting the under side of the hinge when the knee is bent.
Hindsight here again, the wife took a look at the pound of steel in my hand and informed me should would not wear such a thing and there I was stuck unable to make a Resistance is Futile joke of it since she probably has no clue as to Borg, but quickly said have no worries this is just me thinking out loud and I ran downstairs and cut it in half lengthwise and telling myself I meant to do that in the first place.
Be sure to get a heavy duty pair of steel ones, not something flimsy like for a jewelry box, and just start with one an inch to an inch and a half wide in the first place...
I'll make a sketch and scan it into this step in the near future to show the basic layout since I could easily turn simple into a dozen more paragraphs at this point.
But anyways basically the big arc gets welded to the side of the hinge without the slide at about a forty five degree angle towards the slide. Then I placed a half inch on either side of that and welded first the ends of each to the wide strap then a tack in the middle then welded the edges of the two arcs lengthwise, then for good measure added a third on the outside side and repeated the process.
You end up with essentially a crescent moon arc down, the center near the hinge thicker than the edges so it's not gonna go anywhere but won't add a lot of weight.
I then sandblasted the pieces primered them and painted them with black rustoleum, let them flash off for abut half an hour then hung them in a oven preheated to 400 degrees then turned off.
Be sure you remember to turn the thing off before heating the metal, don't tell my wife, and feel completely free to skip this step in favor of drying over night, but this makes the paint flow and it is dry and ready to go an hour later after it has naturally cooled down to room temperature...
Note: I started with little outriggers on the foot but worried they might dig into her leg and I removed them.
Step 3: Keep It Together
To keep the slip joint together and ensure no sharp edges I made a simple pattern from the sleeve of an old parted out leather jacket, thin leather not from like a biker jacket, but denim or anything would do.
Lay to pieces face to face and draw an outline about 3/8 of an inch bigger than the device in it's extended position remembering to keep at least half inch or so of the blade for the slide in the channel, get someone to sew it real good or do it yourself I read a FAQ online and figured it out then turn it inside out, long needle nose pliers are a good thing for this, and slip each half of the slide into a side of the resulting tube, and stitch the tube to the hinge and I had pre drilled a couple small holes for this person I should edit that in when I remember again, but it was simple to stitch a dozen loops through the hinge and get it secure enough that I could not pull the slide completely apart once done.
After that I got some of the webbing and basically made and envelope using two pieces and sewing them along three sides just about a quarter inch wider than the feet and remember the feets are arc so you need to actually lay the double straps on the inside of the curve when you measure, not go in a straight line from end to end. I left a few inches of strap better too much to trim later than not enough and sewed the ends solid like a seatbelt in a car, then slipped the foot into the slot and using the round headed bolts starting on the inside of the curved foot ran them through the top strap with a hole I drilled using the same bit I used to drill the three holes in the foot yes yes I should have also mention that sooner but there it is bolt them down tight and cut the rest of the threads off with a grinder. The bottom strap acts as a heavy duty cushion over the head of the bolts and that is then resting against the original cushioning of the off the shelf leg brace.
Remember to first tighten the center bolt, then drill the holes in the strap for the two ends and keep the strap as flush to the foot as possible.
At this point you just need to secure the strapping sticking out from each end to the brace, keeping in mind that you don't want to attach it wear the velCrow needs to be and once again lots of stitches in an X and in squares just like a seatbelt.
Step 4: And in Conclusion
I wore it for an hour before I tried it on her and it felt about the same as a tight Ace bandage and I ran a couple sprints, it did not lock up and I did not fall on my face as I am Prone to doing..
Seriously it keeps her knee in the proper plane and I can put it on her and take it off in a few seconds unlike her real titanium brace and for short midnight trips to the bathroom at 3 am it is letting me get a bit more sleep.
Participated in the
The Instructables Book Contest