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The Improved shape of handle

THE PROBLEM: The client's hobbies was making products using the hair from pets, and she did every procedure by hand. Before spinning, hair must be un-tangled using carders. Carders are curved rectangular brushes with bristles of kinked wire; they are used to pull clumps of hair apart and thus align the hairs. The handles on the carders were ½ inch diameter dowels, and the client had become unable to grip them hard enough to rake them through the hair. The carders are not simply pulled apart, the mode of the operation is similar to easing the cork from a bottle of champagne, where (for a right-handed person) the left elbow is held against the body with the left lower arm in compression while the left thumb eases the cork, and the right lower arm is in tension.

THE SOLUTION: To find an appropriate shape, a number of handles and sundry items were considered. The finding was that a standard 60 watt light bulb would make an ideal handle. The handles of the carders were made the same shape and size as a light bulb by binding them with strips of duct tape torn to 1 inch wide. The outer surfaces were finished with two half-lap layers of self-amalgamating electrical splicing tap (3M Scotch 130C ethylene propylene rubber). The rubber provided a smooth but uneven, high friction surface, and the duct tape was much cheaper than the splicing tape. In addition, a canvas strap was fastened to the “right” carder and arranged such that it passed behind the client's upper arm: this significantly reduced the grip that had to be applied by the right hand. The pressure on the right upper arm was further reduced by passing the canvas strap through two slots in a patch of leather, just like how leather holsters are mounted to a tool belt.

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