Patent ID: 6286881
Filing Date: 2001-09-11
Classification: B66C

Abstract:
A load clamping and lifting apparatus comprising a link mechanism in which a pair of clamping members and a plurality of members are supported by a plurality of pivot shafts, wherein an upper part of said link mechanism is lifted and lowered by lifting means, and said clamping members rotate about a pivot shaft in response to vertical extension and contraction of said link mechanism, thereby enabling an object to be grasped by distal end portions of said clamping member through jigs by the extension of said link mechanism, and allowing said object to be released from the distal end portions of said clamping members by the contraction of said link mechanism,said apparatus further comprising a lock-unlock mechanism actuated in response to the vertical extension and contraction of said link mechanism, which is caused by vertical movement of said lifting means, to lock said clamping members in respective predetermined positions of rotation about said pivot shaft and to unlock said clamping members in response to the vertical movement of said lifting means;wherein said lock-unlock mechanism has a frame provided with a guide groove, a latch projection integrally formed with said frame such that said latch projection projects into said guide groove, and a shunting member;wherein said frame is attached to a member constituting one of said link mechanism or a member that moves in response to extension and contraction of said link mechanism, and said guide groove is pierced with a projecting pin providing on a member constituting one of a clamping member, said link mechanism or a member that moves in response to extension and contraction of said link mechanism, said projecting pin being movable in said guide groove;wherein said shunting member is rotatably supported on said frame by a pivot shaft such that a distal end of said shunting member projects into said guide groove so that said shunting member is rotated by movement of said projecting pin in one direction, and rotation of said shunting member caused by movement of said projecting pin in an opposite direction is limited by limiting means; andwherein said guide groove is formed such that after said projecting pin has moved in said one direction past said latch projection, movement of said projecting pin in said opposite direction is limited by said latch projection, and when said projecting pin moves in said opposite direction after in said one direction by a predetermined distance past said shunting member, said shunting member enables said projecting pin to bypass said latch projection and to move in said opposite direction.