The objective of this design project was to assist an individual with opening canned foods through the use of an automated can opener. The individual is paraplegic, having suffered a spinal fracture at the C5 - C6 vertebral level. The injury left the individual with little finger dexterity and limited hand motion. He has found it difficult to position cans for a can opener while simultaneously attempting to operate the device.
The client is confined to a wheelchair with his back strapped to the vertical back of the chair. His reach from this position from shoulder to hand is 25 inches. He is able to reach only 14 inches beyond his knees. Sitting in his wheelchair, his height is 36 inches. He is not able to exert control over the movement of his vingers, but he can force a can into this hand.
In approaching a solution to this problem, the emphasis was on the client's abilities rather than his disabilities. Since he had good horizontal reach (25 in.), and had learned to have good control of his arms, the solution used those qualities and lent aid when use of the fingers would have normally been necessary. The concept of the device was to allow the client to place the can to be opened anywhere on a flat platform, and have the can automatically located for opening. An electric opener would then be lowered to the can lip, and activated by the user.
The first part designed was the positioning apparatus. Positioning was accomplished by using a 'V' block locater. The can to be opened was to be placed on the lower platform of the device, and a flat slider used to push the can into the 'V' block until it stopped. The flat slider was actuated using a threaded rod turned by a reversible AC motor underneath the platform. A microswitch located on the platform stopped the motor when the can was in position.
For the opening mechanism, a commercial off-the-shelf device made by Krups was chosen. Using a premanufactured device allowed for replacement of worn or faulty opening mechanisms. The particular model chosen, the Krups Open Master, was identified because it opens cans without leaving sharp edges, and without the problem of getting the cut lid off of the can after it has been opened.
The opening mechanism was mounted to a height-adjustable column to allow for raising and lowering the opener. This mechanism operates similar to the sliding plate on the positioning apparatus, with a threaded rod turned by an AC motor. Both threaded rods allow for an advancement rate of 0.43 inches per second.
In order to allow for opening cans much smaller in height than standard cans, a 'puck' was constructed. The 'puck' was approximately 2 inches tall, and topped by a magnet to attach it to the can to be opened.
Below is a cost breakdown of the device, including machine-shop labor. Design labor was not included, but approximate design time was 270 hours.
This project could be applied for use by anyone who has limited use of his hands, especially in grasping. Many progressive disabilities are manifested in loss of fine motor control. In addition, persons who are hemiplegic, who have use of only one side of their bodies, could benefit from this device. The cost may prove to be prohibitive, though.
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