Fluid pressure cylinder having lock mechanism

A fluid pressure cylinder comprising:

• a cylinder body, a piston which is provided in said cylinder body and operated by a fluid pressure applied to said piston, a piston rod which is provided in said cylinder body and extended from said piston, and a lock mechanism which is provided in said cylinder body for locking said piston rod in a predetermined operation position,
• wherein said lock mechanism comprises an annular lock plate tiltably fitted to sa id piston rod for locking said piston rod by tilting movement, a fulcrum pin for tiltably supporting said lock plate on said cylinder body around one point of an outer periphery of said fulcrum pin, biasing means for tilting said piston rod in its locking direction around said fulcrum pin, and returning means for returning said tilted lock plate in a lock-releasing direction by the fluid pressure applied thereto,
• said returning means comprises a pressure chamber for introducing a pressurized fluid, a pressure receiving member comprising a single annular member which is operated by the fluid pressure introduced into said pressure chamber for returning said lock plate in said lock-releasing direction, and
• said pressure receiving member is provided at its inner peripheral end and outer peripheral end with seal portions, and in a state where said seal portion of said inner peripheral end is abutted against an outer peripheral surface of a sleeve which fluid-tightly guides said piston rod and said seal portion of said outer peripheral end is abutted against an inner peripheral surface of said pressure chamber, said pressure receiving member is disposed such as to partition one side of said pressure chamber at a position adjacent said lock plate and is connected to an end surface of said lock plate,
• wherein said cylinder body and lock plate are provided with holes through which a pin for temporarily holding said lock plate in said lock-releasing position is inserted.

A fluid pressure cylinder comprising:

• a cylinder body, a piston which is provided in said cylinder body and operated by a fluid pressure applied to said piston, a piston rod which is provided in said cylinder body and extended from said piston, and a lock mechanism which is provided in said cylinder body for locking said piston rod in a predetermined operation position,
• wherein said lock mechanism comprises an annular lock plate tiltably fitted to said piston rod for locking said piston rod by tilting movement, a fulcrum pin for tiltably supporting said lock plate on said cylinder body around one point of an outer periphery of said fulcrum pin, biasing means for tilting said piston rod in its locking direction around said fulcrum pin, and returning means for returning said tilted lock plate in a lock-releasing direction by the fluid pressure applied thereto,
• said returning means comprises a pressure chamber for introducing a pressurized fluid, a pressure receiving member comprising a single annular member which is operated by the fluid pressure introduced into said pressure chamber for returning said lock plate in said lock-releasing direction, and
• said pressure receiving member is provided at its inner peripheral end and outer peripheral end with seal portions, and in a state where said seal portion of said inner peripheral end is abutted against an outer peripheral surface of a sleeve which fluid-tightly guides said piston rod and said seal portion of said outer peripheral end is abutted against an inner peripheral surface of said pressure chamber, said pressure receiving member is disposed such as to partition one side of said pressure chamber at a position adjacent said lock plate and is connected to an end surface of said lock plate,
• wherein said biasing means comprises a plurality of coil springs, said coil springs are disposed adjacent to each other substantially in opposite position from said fulcrum pin of said lock plate with respect to said piston rod.