US Patent: 4,895,057
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| Machine Tool For Broaching Crankshaft Connecting Rod Bearings
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Patentees:
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| Garri Berstein (exact or similar names) - Erkelenz, Heinsberg District, North Rhine-Westphalia, Germany |
| Hans W. Obrig (exact or similar names) - Essen, Düsseldorf Region, North Rhine–Westphalia, Germany |
| Hermann Wolters (exact or similar names) - Mönchengladbach, Düsseldorf Region, North Rhine-Westphalia, Germany |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Oct. 16, 1987 |
| Granted: |
Jan. 23, 1990 |
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Joel Havens
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Description: |
| Abstract:
The known turn broaching of crankshaft main bearings is not suitable for broaching crankshaft bearing pins for the connecting rods because that would require locating the rotational axis of the crankshaft in the connecting rod bearing pins, whereby the crankshaft would rotate eccentrically. The resulting unbalances prevent driving the crankshaft with the r.p.m. required for the turn broaching operation. To avoid this problem a broaching lathe for the rotational or turn broaching of crankshaft connecting rod bearing pins is equipped with a steady rest including a rotating support device which permits mounting the crankshaft in the lathe in such a way that the rotational axis coincides with the axis of the connecting rod bearings of the crankshaft.
Claim:
A machine tool for turn broaching crankshafts having main bearing pins and crank pins having an unbalance, comprising crankshaft mounting means for mounting a crankshaft for rotation about an eccentric rotational axis defined by said crank pins thereby permitting said crankshaft to rotate in an eccentric manner relative to its normal rotational axis defined by said main bearing pins, means for rotating said crankshaft about said eccentric rotational axis, broaching tool means mounted for performing a broaching operation on said crankshaft, said crankshaft mounting means including at least one steady rest means (1) including rotatable crankshaft support means (4, 5, 6) for supporting said crankshaft when it is rotating in an eccentric manner, said rotatable crankshaft support means comprising holding elements (7, 8) for contacting eccentric crankshaft portions (10) and means (38, 38a) journalling said holding elements for changing the position of said holding elements (7, 8) when said rotatable crankshaft support means are rotating so that radially outwardly directed centrifugal forces contribute to a radially inwardly directed holding force component exerted by said holding elements, whereby centrifugal forces caused by said eccentric crankshaft portions are at least partially compensated by said radially inwardly directed force component. |
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