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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
Posted to rec.crafts.metalworking
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Rollerblades ...
Here's the deal - a friend of mine is a below-the-knee amputee , and he
wants to rollerblade . He's done some research and others have done this before . Next week I'll be receiving a prosthetic ankle and a rollerblade .... and my job is to fabricate a plate to mate the 'blade truck to the ankle .. I've got the engineering pretty much done on how it'll be made , but I have a question . How stiff should the plate be ? There's a little flex in the sole of the skate , but how much of that flex is actually transmitted to the truck and wheels ? I'm leaning towards a fairly thin plate with ribs below for rigidity with minimum weight . This will be cast from (probably) A356 aluminum or similar casting grade alloy . -- Snag Learning keeps you young ! |
#2
Posted to rec.crafts.metalworking
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Rollerblades ...
Snag wrote:
Here's the deal - a friend of mine is a below-the-knee amputee , and he wants to rollerblade . He's done some research and others have done this before . Next week I'll be receiving a prosthetic ankle and a rollerblade ... and my job is to fabricate a plate to mate the 'blade truck to the ankle . I've got the engineering pretty much done on how it'll be made , but I have a question . How stiff should the plate be ? Very. the stress on a normal ankle is tremendous. I can't flex my ankle in any direction because of the stiffness of the boot (pretty hard molded plastic). There's a little flex in the sole of the skate , but how much of that flex is actually transmitted to the truck and wheels ? I'm thinking it's some but not much. That's what you steer with. Leaning one way or the other causes the trucks to turn (just a little bit!) I'm leaning towards a fairly thin plate with ribs below for rigidity with minimum weight . This will be cast from (probably) A356 aluminum or similar casting grade alloy . Is there some reason not to use a regular boot type arrangement on an artificial foot? Can't help much there. One would think the loads are mostly compressive, but there is a substantial side load, and a bending load on the toe brake . Would sure like to see it when it's done. -- Richard Lamb http://www.home.earthlink.net/~cavelamb http://www.home.earthlink.net/~sv_temptress |
#3
Posted to rec.crafts.metalworking
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Rollerblades ...
CaveLamb wrote:
Snag wrote: Here's the deal - a friend of mine is a below-the-knee amputee , and he wants to rollerblade . He's done some research and others have done this before . Next week I'll be receiving a prosthetic ankle and a rollerblade ... and my job is to fabricate a plate to mate the 'blade truck to the ankle . I've got the engineering pretty much done on how it'll be made , but I have a question . How stiff should the plate be ? Very. the stress on a normal ankle is tremendous. I can't flex my ankle in any direction because of the stiffness of the boot (pretty hard molded plastic). There's a little flex in the sole of the skate , but how much of that flex is actually transmitted to the truck and wheels ? I'm thinking it's some but not much. That's what you steer with. Leaning one way or the other causes the trucks to turn (just a little bit!) I'm leaning towards a fairly thin plate with ribs below for rigidity with minimum weight . This will be cast from (probably) A356 aluminum or similar casting grade alloy . Is there some reason not to use a regular boot type arrangement on an artificial foot? Can't help much there. One would think the loads are mostly compressive, but there is a substantial side load, and a bending load on the toe brake . Would sure like to see it when it's done. -- Richard Lamb http://www.home.earthlink.net/~cavelamb http://www.home.earthlink.net/~sv_temptress The setup this guy wants is the ankle bolted to a plate with the truck bolted under it . Who am i to second-guess him ? My reply-to is good , send me a note so I have your email and I'll send pics of what I'm trying to "match" and some shots of what I build for him . -- Snag Learning keeps you young ! |
#4
Posted to rec.crafts.metalworking
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Rollerblades ...
On Sun, 19 Jun 2011 20:47:18 -0500, "Snag" wrote:
Here's the deal - a friend of mine is a below-the-knee amputee , and he wants to rollerblade . He's done some research and others have done this before . Next week I'll be receiving a prosthetic ankle and a rollerblade ... and my job is to fabricate a plate to mate the 'blade truck to the ankle . I've got the engineering pretty much done on how it'll be made , but I have a question . How stiff should the plate be ? There's a little flex in the sole of the skate , but how much of that flex is actually transmitted to the truck and wheels ? I'm leaning towards a fairly thin plate with ribs below for rigidity with minimum weight . This will be cast from (probably) A356 aluminum or similar casting grade alloy . Need some roller blades..I have extras. Quite a number of them actually. Most of the blades use the truck blade to keep the wheels from flexing out of a straight line. ....IE..they are kept in a linear line. There is supposed to be NO flex in the blade Gunner -- Maxim 12: A soft answer turneth away wrath. Once wrath is looking the other way, shoot it in the head. |
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