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Length Measuring Apparatus

IP.com Disclosure Number: IPCOM000043094D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Smith, GM: AUTHOR

Abstract

The length of an elongated article is tested to determine whether or not it lies between prescribed limits. The apparatus used has two pivoted arms across which the article, the length of which is to be tested, is moved while supported in the apparatus with one end at a known datum position. One arm has a projection extending from it into the plane of movement of the article at a position corresponding to the minimum prescribed length of the article so that if the article contacts the projection and moves the pivoted arm, then it exceeds the minimum prescribed length.

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Length Measuring Apparatus

The length of an elongated article is tested to determine whether or not it lies between prescribed limits. The apparatus used has two pivoted arms across which the article, the length of which is to be tested, is moved while supported in the apparatus with one end at a known datum position. One arm has a projection extending from it into the plane of movement of the article at a position corresponding to the minimum prescribed length of the article so that if the article contacts the projection and moves the pivoted arm, then it exceeds the minimum prescribed length. The other arm also has a projection extending from it into the plane of movement of the article at a position corresponding to the maximum permitted length of the article so that if the article contacts the projection and moves the arm, then it exceeds the maximum prescribed length. A simple optical system detects whether neither, one, or both arms move, indicating whether the article tested is too short, within limits, or too long. The arrangement shown in plan and side elevation in the figure uses this principle to check the lengths of two tails 1 and 2 of a wire coil spring 3 (shown in phantom) extending substantially parallel to each other in the same direction from opposite sides of the coil. The two tails in this example are of slightly different lengths. The apparatus consists of an upper arm 4 and a lower arm 5 pivotally mounted on a common spindle 6 by means of low friction roller bearing 7. The spindle projects above the upper arm and is of a diameter suitable to support the coil of a spring under test. Individual wire coil springs 8 and 9 extend into longitudinal bores in the pivoted ends of the two arms 4 and 5, respectively, and are adjustable (as indicated schematically by the arrows) to bias the arms to a central position accurately located one above the other. The upper arm carries a block 10 extending into the plane of the tails of the spring under test. The block has two projecting machined edges 11 and 12 extending in a direction towards the pivot. The distance from the pivot to the edge 11 defines the minimum length of the tail 1 and the distance from the pivot to the edge 12 defines the minimum length of the tail 2 of the spring. Similarly, the lower arm carries a block 13 with two projecting edges 14 and 15 defining the maximum length of...