Cylinder device with force multiplier

A cylinder device, having a force multiplier, comprising (i) an output rod (2) inserted in a housing (1) so as to be movable axially, (ii) a first piston (21) for rod, the first piston (21) being coupled to the output rod (2) in the housing (1), and (iii) a second piston (22) for force multiplication, the second piston (22) being arranged in the housing (1) in tandem with the first piston (21), the second piston (22) being fitted on the output rod (2) so as to be movable axially, said cylinder device being configured such that in lock driving of the output rod (2), (a) the first piston (21) drives the output rod (2) during a low-load stroke and (b) the second piston (22) carries out force multiplication driving with respect to the output rod (2) by use of the force multiplier (36) during a high-load stroke that follows the low-load stroke,

• said cylinder device, further comprising:
• a lock chamber (25), arranged between the first piston (21) and the second piston (22), into and out of which a pressurized fluid is supplied and discharged, such that the first piston (21) and the second piston (22) are pushed in such directions as to be away from each other;
• a first release chamber (31) arranged such that the first piston (21) is pushed toward the second piston (22);
• and
• a second release chamber (32) arranged such that the second piston (22) is pushed toward the first piston (21),
• the force multiplier (36) having a wedge space (39) which is formed between a transmitting portion (37) provided in the output rod (2) and a receiving portion (38) provided in the housing (1) during the force multiplication driving so as to get narrower as it extends radially inward, an engaging member (40) put in the wedge space (39), and a force-multiplying portion (41) which is provided in the second piston (22) so as to push the engaging member (40) radially inward,
• said cylinder device including a press portion (48) provided in the second piston (22) so as to push the engaging member (40) radially inward and toward the outer circumferential surface of the output rod (2) during the low-load stroke of the output rod (2), the press portion being for pushing out the engaging member (40) toward the wedge space (39) at a start of the force multiplication driving,
• the force multiplier (36) causing (i) a first force, with which a pressurized fluid supplied into the lock chamber (25) pushes the second piston (22) in a direction away from the first piston (21), to be reversed to be a second force getting toward the first piston (21) and (ii) the second force to be subjected to force multiplication so as to be transmitted to the output rod (2).

A cylinder device, having a force multiplier, comprising (i) an output rod (2) inserted in a housing (1) so as to be movable axially, (ii) a first piston (21) for rod, the first piston (21) being coupled to the output rod (2) in the housing (1), and (iii) a second piston (22) for force multiplication, the second piston (22) being arranged in the housing (1) in tandem with the first piston (21), the second piston (22) being fitted on the output rod (2) so as to be movable axially, said cylinder device being configured such that in lock driving of the output rod (2), (a) the first piston (21) drives the output rod (2) during a low-load stroke and (b) the second piston (22) carries out force multiplication driving with respect to the output rod (2) by use of the force multiplier (36) during a high-load stroke that follows the low-load stroke,

• said cylinder device, further comprising:
• a lock chamber (25), arranged between the first piston (21) and the second piston (22), into and out of which a pressurized fluid is supplied and discharged, such that the first piston (21) and the second piston (22) are pushed in such directions as to be away from each other;
• a first release chamber (31) arranged such that the first piston (21) is pushed toward the second piston (22);
• and
• a second release chamber (32) arranged such that the second piston (22) is pushed toward the first piston (21),
• the force multiplier (36) having an engaging member (40) which (i) is mounted between the output rod (2) and the second piston (22) and (ii) prevents the second piston (22) from moving in a direction away from the first piston (21) during the low-load stroke,
• the force multiplier (36) causing, during the high-load stroke, (i) a first force, with which a pressurized fluid supplied into the lock chamber (25) pushes the second piston (22) in the direction away from the first piston (21), to be reversed via the engaging member (40) to be a second force getting toward the first piston (21) and (ii) the second force to be subjected to force multiplication so as to be transmitted to the output rod (2).