Abstract: A first piston (22) of a first locking cylinder (20) descends when a pressure of compressed air in an actuation chamber (23) has exceeded a pressure for locking commencement (P1) and ascends by a first spring (24) when the pressure of the compressed air has decreased to a pressure for releasing commencement (P2). A second advancing and retreating cylinder (32) comprises an inlet chamber (41) and an outlet chamber (45) formed below and above a second piston (35), respectively, and a second spring (46). The actuation chamber (23) communicates with the outside air through the outlet chamber (45). A restricting passage (37) is provided in a route between the actuation chamber (23) and the outside air. The actuation chamber (23) communicates with one of the inlet chamber (41) and the outlet chamber (45) through a communication hole (62).

Abstract: A housing (3) has an upper end wall (3a) which supports an upper slide portion (11) of a clamp rod (5) vertically movably. The housing (3) has a lower end wall (3b), a support cylinder (13) of which supports a lower slide portion (12) of the rod (5) vertically movably. The rod (5) is provided with an input portion (14) between the upper slide portion (11) and the lower slide portion (12). A clamp spring (20) connected to the input portion (14) drives the rod (5) downwards for clamping. The lower slide portion (12) has an outer periphery provided with a helical rotary groove (27) and a straight groove (28) which is in upward continuity with the rotary groove (27). A ball (29) engages with the rotary groove (27) and the straight groove (28). The ball (29) is supported by an inner wall (13a) of the support cylinder (13).

Abstract: A clamp rod (5) is inserted into a housing (3) rotatably around an axis and movably downwards for clamping. The clamp rod (5) has an outer peripheral portion formed with three guide grooves (26) which are arranged peripherally at substantially the same spacing. An engaging ball (29) which is fitted into every guide groove (26) is supported by a lower end wall (3b) of the housing (3). Each of the guide grooves (26) comprises a rotary groove (27) and a straight groove (28) which is in upward continuity with the rotary groove (27). The rotary grooves (27) as well as the straight grooves (28) are arranged in parallel with one another. A partition wall between the adjacent guide grooves (26), (26) has a minimum thickness (T) set to a value smaller than a diameter (D) of the engaging ball (29).

Abstract: A clamp pallet (2) is fixed to a table (1) of a machining center. A work pallet (3) has a positioning hole (12) and an engaging hole (13) formed in order from a lower side. A plug portion (21) projects upwards from the clamp pallet (2). A shuttle member (23) is vertically movably fitted onto the plug portion (21). A coned disc spring (24) urges the shuttle member (23) upwards. The shuttle member (23) has a tapered surface (28) with which the positioning hole (12) makes a tapering engagement. A pull rod (31) is inserted into the plug portion (21). The pull rod (31) pushes engaging balls (34) to the engaging hole (13), thereby driving the work pallet (3) downwards.

Abstract: A manifold (2) is provided with a first passage (4) for supplying pressurized oil and a second passage (5) for air venting. The manifold (2) has a support surface (9) to which a housing (12) of every hydraulic cylinder (7) is hermetically fixed through a sealing member (10). A piston (14) is inserted into a cylinder bore (13) of the housing (12). A hydraulic chamber (15) is formed between the piston (14) and the support surface (9). The hydraulic chamber (15) directly opposes to the support surface (9). The first passage (4) communicates with the respective hydraulic chambers (15) through branched passages (17). The hydraulic chamber (15) has an upper portion communicated with the second passage (5) through an air vent passage (18).

Abstract: Two hydraulic chambers (3a),(3b) within a slide (2) communicate with an overload protecting valve (12) through relief passages (11a),(11b). Check valves (13a),(13b) and discharge valves (14a),(14b) are arranged in series with each other in the respective relief passages (11a),(11b). When either of the two hydraulic chambers (3a),(3b) has a pressure not less than a set overload pressure, the overload protecting valve (12) opens to relieve pressurized oil within the hydraulic chamber (3a) to an exterior area via a restricting passage (78) of one discharge valve (14a) and the overload protecting valve (12). This switches over the two discharge valves (14a),(14b) to a discharging condition substantially at the same time to communicate the hydraulic chambers (3a),(3b) with a discharge port (R).

Abstract: When clamping, compressed air within a second chamber (22) of a pneumatic cylinder (12) is discharged and fresh compressed air is supplied to a first chamber (21). Then a pressure of the compressed air within the first chamber (21) and an urging force of a compression spring (25) move a piston (20) leftwards. The piston (20) moves an output rod (26) rightwards strongly through a plurality of engaging balls (34) and a first pressure receiving member (31). When unclamping, the compressed air within the first chamber (21) is discharged and fresh compressed air is supplied to the second chamber (22). Then a pressure of the compressed air within the second chamber (22) moves the piston (20) rightwards and at the same time the output rod (26) leftwards.

Abstract: A housing (4) has a cylinder bore (10) into which an annular hydraulic piston (11) is inserted vertically movably. The piston (11) has a tubular bore (11a) into which a driven rod (6) is inserted. The driven rod (6) is provided with an input portion (6a), around which a plurality of transmission members (15) are arranged peripherally side by side. The transmission members (15) swing to a disengaging position (Y) through a push member (30) by a lowering spring (31). When clamping, the piston (11) is driven upwards. Then, first, a slant cam (27) swings the transmission members (15) to an engageable position (X), thereby enabling engaging portions (17) to face the input portion (6a). Next, the piston (11) upwardly drives the input portion (6a) through the engaging portions (17).

Abstract: When clamping, compressed air within a second chamber (22) of a pneumatic cylinder (12) is discharged and fresh compressed air is supplied to a first chamber (21). Then a pressure of the compressed air within the first chamber (21) and an urging force of a compression spring (25) move a piston (20) leftwards. The piston (20) moves an output rod (26) rightwards strongly through a plurality of engaging balls (34) and a first pressure receiving member (31). When unclamping, the compressed air within the first chamber (21) is discharged and fresh compressed air is supplied to the second chamber (22). Then a pressure of the compressed air within the second chamber (22) moves the piston (20) rightwards and at the same time the output rod (26) leftwards.

Abstract: A manifold (2) is provided with a first passage (4) for supplying pressurized oil and a second passage (5) for air venting. The manifold (2) has a support surface (9) to which a housing (12) of every hydraulic cylinder (7) is hermetically fixed through a sealing member (10). A piston (14) is inserted into a cylinder bore (13) of the housing (12). A hydraulic chamber (15) is formed between the piston (14) and the support surface (9). The hydraulic chamber (15) directly opposes to the support surface (9). The first passage (4) communicates with the respective hydraulic chambers (15) through branched passages (17). The hydraulic chamber (15) has an upper portion communicated with the second passage (5) through an air vent passage (18).

Abstract: A pneumatic hydraulic booster pump (5), an overload protecting valve (10) and a pressure compensating valve (14) are connected in parallel with an overload absorbing hydraulic chamber (3) within a slide (2) of a mechanical press (1). The pressure compensating valve (14) has a restricting passage (60) and a relief valve (61) connected to each other in series. The relief valve (61) comprises a valve closing piston (71) which pushes a relief member (72) in a direction for valve closing, a valve closing actuation chamber (73) which communicates with a compressed air supply passage (30) of the booster pump (5), and a compression spring (74) which urges the relief member (72) in the direction for valve closing.

Abstract: A main valve (5) has a first valve seat (11) to which a compression spring (21) urges a first closure member (14). A restricting passage (16) and an actuation chamber (17) for valve closing are arranged within the first closure member (14) in order. A valve-opening holding chamber (25) is formed from an inner space defined by a fitting wall (23) with which the first closure member (14) fits at a final time of its closing movement. The actuation chamber (17) communicates with a second valve seat (31) of a pilot valve (6). A pushing spring (37) brings a second closure member (34) into closing contact with the second valve seat (31). The second valve seat (31), the first valve seat (11), the actuation chamber (17) and the valve-opening holding chamber (25) have respective sectional areas (S), (T), (U) and (V) set to values enlarging one after the other in the mentioned order.

Abstract: An annular piston (4) is inserted into a housing (1) axially movably but unrotatably. A clamp rod (9) is hermetically inserted into a through-hole (4a) of the piston (4). When the piston (4) is lowered by a clamping spring (20), a back pressure is produced in pressurized oil within a second chamber (12) formed below the piston (4). The back pressure pushes an input portion (9a) for clamping provided at a lower end of the clamp rod (9) to a stopper (23) through a bearing (24) and a transmission plate (25). The piston (4) is lowered relatively to the clamp rod (9) at a raised position, whereby the clamp rod (9) is rotated by a converting mechanism (21).

Abstract: A driving member (15) of piston type has an upper side, on which an annular holder (28), upper and lower cams (31), (32), and a transmission sleeve (33) are arranged in order. An annular wedge space (35) is defined between the upper and lower cams (31) and (32). A plurality of wedging members (36) are inserted into the wedge space (35) and peripherally spaced apart at a predetermined distance. When the driving member (15) is driven upward, first a plurality of engaging balls (41) supported by the transmission sleeve (33) engage with a lower portion of a pull rod (12) and then a pushing surface (38) of the driving member (15) vertically separates the cams (31),(32) from each other through the wedging members (36). Thus the lower cam (32) drives the pull rod (12) downward through the transmission sleeve (33) and the engaging balls (41).

Abstract: A housing (11) has a piston (17) inserted thereinto. A pull rod (12) is connected to the piston (17). An annular collet (13) is externally fitted onto the pull rod (12). When clamping, an engaging member (14) provided on a peripheral wall of the collet (13) is inserted into an engaging hole (2) of a workpiece (1) and the piston (17) is lowered. Then a tapered outer peripheral surface (12a) of the pull rod (12) diametrically expands the engaging member (14) to engage it with the engaging hole (2) and the collet (13) slightly descends against a push spring (27). Thus a downward driving force acting on the pull rod (12) is transmitted to the workpiece (1) via the engaging member (14) and the workpiece (1) is pulled and fixed to a support surface (S) of the housing (11).

Abstract: A stop valve (7) and a pressure reducing valve (8) are arranged in series with each other within a housing (3). A first check valve (11) is arranged in a gas charging passage (10) provided in parallel to the pressure reducing valve (8). The pressure reducing valve (8) is adapted so as to move a piston member (59) for opening and closing by a balance between a spring force for valve opening and a secondary pressure for valve closing. A first coned disc spring (F) urges the piston member (59) toward an opening direction. The first coned disc spring (F) is connected in series with a second coned disc spring (S). The second coned disc spring (S) is compressed by a pushing member (66) projecting from a cap member (61).

Abstract: A housing (11) includes an annular driving member (16), into which a cylindrical pull rod (12) is inserted. An actuation member (26) is inserted into the pull rod (12). At the time of clamping, the pull rod (12) has an upper end portion fitted into a stepped hole (2) of a workpiece (1) and the driving member (16) is lowered. Then, first the pull rod (12) descends relatively to the actuation member (26) to project a plurality of engaging balls (13) outwards and subsequently these balls (13) are brought into butting contact with a lower step portion (8) of the stepped hole (2). Thus the driving member (16) pulls the workpiece (1) downward through the pull rod (12) and the balls (13).

Abstract: An annular collet (10) is externally fitted to a support rod (4) inserted into a housing (2), and an annular transmission member (14) is arranged around the collet (10) with an annular tapered clearance (C) interposed therebetween. A large number of balls (B) inserted into the annular tapered clearance (C) are pushed up by a pushing spring (17). When pressurized oil is supplied to a hydraulic actuation chamber (25), a clamping piston 24 moves the transmission member (14) downward, so that a tapered internal peripheral surface (15) of the transmission member (14) gets engaged with a tapered external peripheral surface (11) of the collet (10) while rolling the balls (B). Thereby, the collet (10) is diametrically contracted.

Abstract: An upper end wall (3a) and a lower end wall (3b) of a housing (3) are adapted to support an upper sliding portion (11) and a lower sliding portion (12) of a clamp rod (5), respectively. A rotary portion (26) is provided on the clamp rod (5) below a piston (15) fixed to the clamp rod (5). A rotation actuating sleeve (27) is externally fitted onto the rotary portion (26) axially movably but unrotatably. The sleeve (27) is urged upward by a pushing spring (31) and prevented from moving farther than a predetermined distance by a stopper (32). An axial movement of the clamp rod (5) is converted to a rotary movement by a converting mechanism (34).

Abstract: A clamp rod has an outer peripheral surface provided with a first concaved passage communicated in entirety of the outer peripheral surface and in the shape of sawtooth. The first concaved passage comprises first spiral grooves in the shape of a multi-start thread and communication grooves. A sleeve externally fitted onto the clamp rod has an inner peripheral surface provided with a second concaved passage corresponding to the first concaved passage. A number of rolling balls are charged between the first concaved passage and the second concaved passage. The clamp rod and the sleeve are moved in a direction of an axis relatively to each other, thereby rotating the clamp rod around the axis.