Prosthetic Arm Force Reducer Team 1 – Halliday's ... - Ohio University

Appendix C – Tim Lang’s Forearm Dimensions & Data
• Note: All measurements were done with a dial caliper on 2/27/08
Thickness = 0.225”
Overall Length* = 6.80”
Useable Length = 5.50”
Wrist (O.D.) = 2.10”
2” from wrist (O.D.) = 2.45”
4” from wrist (O.D.) = 2.80”
6.8” from wrist (O.D.) = 2.95”
Taper = Continuous through entire length
Cable Dia. = .086” (~3/32”)
Length of Cable Post = 1.0”
Angle of Cable Post = 45° ± 10° (Same as Otto Bock hook)
Depth of Wrist Chuck = 1.0” into forearm (threaded)
Cable Travel = 1.75”
Input Force = 4-6 kg
Flexibility of Cable = able to make 0.5” loop
* - The overall length is the shortest distance from the wrist chuck to the scooped cutout of the
forearm.
UOther Notes
• The prosthetic is comprised of three major parts (the shoulder/upper arm, the elbow, and
the forearm).
• Tim was uncertain of how to disconnect the forearm at the elbow for he has never done it
before. The pictures might yield some clues of how it is done but is can be done.
• The wrist chuck can be completely removed from the forearm via six to eight flat screws.
• The threading of the Otto Bock hook is the same as Tim’s hook
• When the forearm is all the way up, it and touches the elbow unit causing a pinch point at
the scooped cutout of the forearm.
• Tim didn’t seem to have a problem with 1 to 2 lbs of extra weight in the forearm.
• Tim claims that the tighter the harness the less shrugging necessary and the less amount
of cable travel. Also, that he is capable of a larger shrug.
55