| 摘要 |
A crankshaft mechanism for use with a press having a slide member, which includes an eccentric crankshaft. In one form of the mechanism, the crankshaft has a cylindrical eccentric portion. An eccentric sheave is rotatably mounted on the circumference of the eccentric portion so that its center is displaced radially from the center of the eccentric portion. A connecting member is rotatably mounted on the circumference of the sheave. The eccentric portion, sheave, and connecting member have pin-receiving bores whose axes intersect the crankshaft axis. The bores in the crankshaft and connecting rod are both aligned with the sheave bores when the crankshaft and the sheave are in predetermined angular positions. Lock pins in the eccentric portion bore are selectively engageable with the sheave bores to fix the sheave to the eccentric portion. Lock pins in the connecting rod bore are selectively engageable with the sheave bores to fix the sheave to the connecting member. By the selective engagement of the lock pins, the sheave is selective fixed to either the crankshaft or the connecting rod and freely rotatable with respect to the other. In a second form of the mechanism, the crankshaft includes two arm portions between which is connected a first eccentric section, including an eccentric crank-pin portion. A second eccentric section includes an eccentric sheave formed in multiple pieces and mounted on the circumference of the crank-pin portion. A ring member is fitted over the pieces of eccentric sheave to integrate them on the crank-pin portion.
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