Patent ID: 8360210

Claim:
An oil buffer for an elevator, comprising: a base cylinder filled with a hydraulic oil; an upper-stage plunger which is axially slidably inserted into the base cylinder for movement toward the base cylinder over a stroke of axially slidable movement of the upper stage plunger from an elevated position corresponding to an unloaded state to a compressed position corresponding to a loaded state, wherein the upper-stage plunger has an orifice provided in a bottom surface portion thereof; at least one cylindrical intermediate plunger axially slidably inserted into the base cylinder, and including a bottom surface portion opened so as not to provide a superposition effect of the fluid resistance of the orifice and the bottom surface portion; a pin rod, which is provided upright in the base cylinder, and is inserted into the orifice during a portion of the stroke of the upper-stage plunger from the elevated position to the compressed position; and a return spring mounted for causing the intermediate plunger and the upper-stage plunger to return from a position corresponding to the loaded state to the elevated position corresponding to the unloaded state, wherein the pin rod has a length such that a distal end of the pin rod is situated below the orifice when the intermediate plunger adjacent to the base cylinder starts descending from the elevated position thereof.