| US Patent: RE4,019 
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| Improvement in Curtain-Knobs | 
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| Patentee: |  |
 | Calvin Z. Kroh (exact or similar names) - Tiffin, OH |  
 
 
 
 
| Manufacturer: |  | Not known to have been produced |  
 
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| Patent Dates: |  
| Granted: | Jun. 07, 1870 |  
 
| Reissue Information: |  | Reissue of 49,634 (Aug. 29, 1865) |  
 
USPTO (New site tip)| Patent Pictures: |  |  |  | Calvin Z. Kroh reissue Pat. June 7, 1870 |  Google Patents
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                        Stan Schulz
 
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| Description: |  | The improvement is a polygonal bearing surface between the knob and screw to allow the use of a "hollow screw-driver" or "bit-wrench" to install or remove the hardware.  The "bit-wrench" is shown in the drawing.
This curtain knob is to fasten side-curtains on buggies, etc. |  |