US Patent: 583,402
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| Speed-varying mechanism
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Patentee:
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| Milton O. Reeves (exact or similar names) - Columbus, IN |
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Patent Dates:
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| Applied: |
Oct. 12, 1896 |
| Granted: |
May 25, 1897 |
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Jeff Joslin
Vintage Machinery entry for Reeves Pulley Co.
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Description: |
| This is the earliest patent for the Reeves drive mechanism to provide continuously variable speed. This early version was primarily targeted at sawmills. Later versions were applied to everything from drill presses to tractors and even automobiles.The basic Reeves pulley setup consists of two pulleys, each consisting of a pair of truncated-cone disks plus a belt that is stretched between the two pulleys. By inversely varying the spacing between each pair of cones, the effective diameter of each pulley is inversely varied. This basic idea was not new. Reeves' innovation solves a problem with previous versions of this type of drive: the length of belt requires varies slightly as the speed varies because the curves around each pulley an angle that varies from 180 degrees at mid-speed to something greater than 180 at the smallest circumference and less than 180 degrees at largest circumference. Of course, as one pulley is at smallest diameter the other is at largest diameter, but these effects do not exactly cancel out at each speed. Reeves' solution was to make each pulley side, not as a straight-sided truncated cone, but as a curved shape calculated to exactly account for the change in wrap-around angle; the resulting curve is described as an oblate spheroid. This simple change created a constant belt tension regardless of speed, and also enabled more compact versions of the drive with the pulleys closely spaced and a short belt. This mechanism would be improved in patents 588,354 and 630,407. |
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