US Patent: 1,718,505
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| Spring Joint for Folding Rule
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Patentee:
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| Charles G. Watson (exact or similar names) - Seneca Falls, Seneca County, NY |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Feb. 03, 1922 |
| Granted: |
Jun. 25, 1929 |
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Joel Havens
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Description: |
| James L. Norris - patent attorney
This invention relates to folding rules comprising a series of sections terminally overlapped and jointed or connected by hinge plates or members pivotally associated and engaged by frictional springs. In folding rules of the so-called spring joint or zigzag type as heretofore constructed the weak points usually consisted of the pivot pins or studs and the springs interposed between the parts of the joints and especially the spring, in view of the length of the latter or projection in opposite directions from a central pivot pin or stud engaging portion, the extended parts of these springs being always liable to fracture or breakage and also requiring care in the formation and delicacy of operation in tempering the parts thereof. The object of the present improved folding rule joint is to overcome the structural weaknesses of the springs by interposing between the parts of each joint and around the pivot pin or stud a circular or round spring of a dished or cupped form, and whereby the resilient resistance to loose movement of the terminally overlapped and jointed sections of the rule will be positive and strong and durable. The improved circular or round spring embodying the features of the present improvement is sensitively resilient or is quick to respond to pressure and expansion, and on the contrary will resume its normal contour and have a more lasting resilient or spring action than can be obtained by the use of a spring with opposite projecting extremities and a weakened central portion. By dishing or cupping the improved spring it is given a firm bearing and placement relatively to a seat therefor formed in one of the hinge plates or members.
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