| 摘要 |
This invention discloses a heavy-duty live center for a heavy workpiece usually of 10 or more tons. This center includes an outer quill or housing which is movable in a tailstock housing of a lathe or grinder. This live center incorporates the self-aligning front bearing arrangement shown in U.S. Patent application Ser. No. 643,909, filed Dec. 23, 1975. As described in that application this heavy-duty center has the center spindle bowed by the load and as the thrust increases because of heat, etc. there is a Belleville-type spring arrangement which accommodates the increased thrust. The outer housing or quill in the present invention receives the thrust of the load. The quill is moved into a workpiece supporting condition by the action of a screw on an enclosed nut in the rear of the quill. The thrust is measured by a hydraulic load cell and connected hydraulic pressure gage. This gage is carried on the forward exterior part of the housing. The hydraulic pressure is derived from the thrust on a closed circular hydraulic ring portion that measures the total thrust on the center. Belleville-type springs in combination with the hydraulic pressure cell accommodate the increase in thrust which occurs because of heating the workpiece during processing.
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