US Patent: 4,658,859
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| Valve Spool with Cross Drill Ports
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| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Dec. 07, 1984 |
| Granted: |
Apr. 21, 1987 |
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South Bend Lathe History
"Vintage Machinery" entry for South Bend Lathe Works
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Description: |
| Barnes & Thornburg - patent attorneys
Abstract
A four-way valve is provided, for selectively interconnecting pressure supply and return lines with control pressure lines of a hydraulic device, having means for independently balancing the valve against pressures exerted on the valve by any one or more of the pressure lines and at any operating position of the valve. These pressures exerted on the valve would otherwise restrict or prevent actuation of that valve. This balancing means exposes a minimum surface area of the valve to high pressure forces and isolates the fluid pressure in the pressure lines until interconnection is made by valve actuation.
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