Specification of Michael Henry : artificial hands, feet, and limbs.

  • Henry, Michael.
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: Specification of Michael Henry : artificial hands, feet, and limbs. Source: Wellcome Collection.

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    Provisional Henry's Improvements in the (Construction of Artificial Hands, Feet, Limbs. Artificial arm.—A cord is attached at one end to a lever connected to part of the artificial arm, and at the other end to a point on the remaining stump or sentient corporeal part, so that the wearer by a voluntary movement, may open or extend the arm, overcoming the resistance of a spiral spring which tends to close it towards the body; this cord regulates the degree of tension of 5 another cord, according to the position of a pulley over which it passes, and thus actuates the extension of the fingers, the pulley being adjustable by the other hand, with suitable arrangements for regulating the tenacity and vigour of the artificial hand; this may also be done by spiral springs, as herein-after described. The cord operates as a sort of check to regulate, slacken, or 10 moderate the arm’s expansion. The artificial hand may be fitted to tubular pieces of leather or other suitable material, covering the stump where remain¬ ing, simulating the human arm, and together with the hand and mechanism composing the artificial limb. In the arrangement preferred, an armlet is fitted round the stump, serving as the first fulcrum of the action. The afore- 15 said lever is connected thereto. Axes or joints are provided for the play of wrist and elbow. The lever is fitted in the centre of articulation, and attached at the outer end to the tube representing the fore-arm. A sort of hook with toothed wheel may be used to regulate the tension of the regulating cord or cord that transmits action, and a strong spring is set in the centre of the 20 foregoing motion, operating independently or as auxiliary to the first-named spring. For obtaining a motion of the main part of the fore-arm in a rotary direction without interfering with the other mechanism two tubes are provided. Levers and single and double pulleys may be used for increasing, reducing, or regulating the power and time of travel of the limb for better imitating natural 25 action. The fingers are composed of artificial finger joints articulated progres¬ sively and independently, and working nearly at right angles on their centres, which may be of silvered steel, covered with silk cloth or other fabric for resisting oxydation and friction of the material composing the hand. Each articulation has a slot or notch lengthwise of the finger, with a pin across at the 30 part, in which is a recess in each slot serving as a stop and preventing jamming. The tendons consist of cords of sinewy filament, silk, steel wire, or other suitable material attached at their inner ends to points on the stump, whence impulsion may be transmitted to them ; near the bottom of each finger is a spiral spring, which communicates action to the finger joints through the 35 tendons. The axis of each spring is mounted on plates fitted with a square for winding it up and regulating tenacity and vigour of grasp. The tendons that move in an opposite direction to the foregoing are actuated by the articulations and the mechanism of the tubes ; the finger tendons may be worked