| US Patent: 4,970,922 
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| Torque Driving Tool and Retainer for Driven Member | 
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| Patentee: |  |
 | Bert Krivec (exact or similar names) - Waukesha, WI |  
 
 
 
 
| Manufacturer: |  | Not known to have been produced |  
 
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| Patent Dates: |  
| Applied: | Mar. 01, 1990 |  
| Granted: | Nov. 20, 1990 |  USPTO (New site tip)
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                        Stan Schulz
 Snap-On Tools Company History
 
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| Description: |  | Emrich & Dithmar - patent attorneys
Abstract
A rotatable driving tool for imparting torque to a driven member, such as a threaded fastener having an axial recess in the head thereof, comprises a circularly cylindrical body with a plurality of substantially circularly helical driving portions projecting laterally therefrom and equiangularly spaced about the cylindrical axis, each of the driving portions having a small helix angle, preferably between one and three degress. The driving portions mate with lobes of the fastener recess but are slightly inclined with respect thereto to provide a wedge fit to retain the fastener in engagement with the tool body. |  |