US Patent: 877,157
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| Manufacture of wood-screws
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Patentee:
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| William G. Allen (exact or similar names) - Hartford, CT |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Jan. 30, 1906 |
| Granted: |
Jan. 21, 1908 |
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Jeff Joslin
Vintage Machinery entry for Henry & Wright Mfg. Co.
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Description: |
| This patent provides improvements to the process of manufacturing rolled-thread wood screws. Cut screws were expensive to manufacture, and the metallurgical requirements for cutting threads were, to some degree, incompatible with the requirement for swaging the heads. The result was a screw that was brittle and prone to breakage. On the other hand, rolled-thread screws, traditionally produced by forcing wire screw-blanks between a pair of dies a fixed distance apart, were sensitive to slight variations in the wire thickness caused variations in the quality of the threads. In addition the screw heads were swaged first, and wear in the head dies caused variations in shank diameter, which led to malformed threads and jamming of the dies. On the other hand, rolled-thread screws avoided the disadvantages of the cut-thread screws.The new method begins by "rolling the groove between the threads", followed by cutting or grinding the threads to the proper completed form. This additional step allows for variation in the shaping of the thread and removes irregularities. The method proposed that the first step could also be done by cold-swaging, which was reported to be suitable for bolts, where rapidity of production is not as important.The Glbe screw Co. was established in 1907 by the inventor, William G. Allen, along with Robert G. Henry and Daniel M. Wright, who were the principals of Henry & Wright Mfg. Co., manufacturers of light machinery and hardware specialties.See also patent 928,489, which describes the screw-making machinery in more detail. |
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