Abstract: A fine blanking device and method for forming a friction plate with friction material layers. The fine blanking device includes an upper die, a lower die, a guide mechanism, a punch and a counter punch. Upper and lower blank holders are respectively provided at outer circumferences of the punch and the counter punch. The upper and lower blank holders are respectively provided with a buffer mechanism. Friction material powders are sintered on both sides of the base sheet. The friction material layers are trimmed and planished by hot pressing. The base sheet with the friction material layers is fixed by the upper blank holder and the lower blank holder. A tooth profile with an absolute shear fractural surface is formed. The fixing indentation of the V-shaped structure of the friction material layers is cut off for obtaining a finished friction plate product with the friction material layers.

Abstract: A system comprises a ram tool subassembly and a master die subassembly. The ram tool subassembly further comprises a tool stick, a back body, a piston assembly, a piston housing, and a pusher holder. The master die subassembly further comprises a bottom tooling plate, a bottom master jaw, a nose block, a top master jaw, and a top tooling plate.

Abstract: Disclosed is a process for the blanking of metal parts, in which a multi-layered basic material with a number of mutually stacked, preferably essentially identical, individual layers is placed and clamped partly between a blanking die and a blank holder and partly between a blanking punch and a counter punch and wherein the blanking punch and the counter punch that are moved relative to the blanking die and the blank holder over a distance corresponding to at least a thickness of the multi-layered basic material whereby several blanked parts are cut and separated from the multi-layered basic material.

Abstract: A clamping plate is dimensioned to secure a flexible spring member to an end member for forming a gas spring assembly. The clamping plate includes a clamping plate wall with an axis and opposing surface portions oriented transverse to the axis. An opening extends into the clamping plate wall from along each of the opposing surface portions. An elongated damping passage extends in a spiral configuration through the clamping plate wall in fluid communication with the openings. A gas spring assembly includes a flexible spring member that defines a spring chamber, and an end member with an end member wall that defines an end member chamber. The clamping plate is secured to the end member and retains the flexible spring member thereon. The elongated damping passage is in fluid communication between the spring chamber and the end member chamber. Gas transfer between the spring chamber and the end member chamber generates pressurized gas damping during use of the gas spring assembly.

Abstract: A gas spring with a casing with an axially extending side wall, an open end and a closed end wall spaced from the open end and a pressure chamber provided in part by the walls to receive a gas therein under pressure and a piston rod slidably received in a housing received in the casing and movable between extended and retracted positions. A pressure relief collar slidably carried around the piston rod and normally projecting axially outwardly of the casing can be displaced axially inwardly during an overtravel condition of the piston rod to displace a portion of a piston rod seal to open an overpressure relief path to allow pressurized gas in the pressure chamber to escape to the outside of the gas spring.

Abstract: A gas cylinder actuator with safely device, comprising a tubular containment jacket, two opposite heads for closing the tubular jacket, with corresponding sealing elements between the heads and the jacket, a first head having a through hole for the passage of a stem-piston, and a second opposite head, a stem-piston, between the tubular jacket, the heads and the stem-piston there being a chamber for pressurized gas, wherein at least one head of the two heads is constituted by a body that is separate with respect to the tubular jacket and is retained in the tubular jacket by means of an extraction-preventing shoulder that protrudes from the body of the head and is adapted to abut against a corresponding internal annular protrusion that protrudes radially from the internal surface of the tubular jacket.

Abstract: A gas cylinder actuator with overtravel safety device, comprising: a tubular containment jacket, two opposite heads for closing the tubular jacket, with corresponding sealing elements between the heads and the jacket, one head of which being provided with a through passage hole for a stem-piston, a stem-piston, between the tubular jacket, the heads and the stem-piston there being a chamber for pressurized gas, the gas cylinder actuator being characterized in that the tubular jacket has, at at least one of the portions affected by a head, a lightened portion that is preset to be deformed in case of compression in an axial direction, allowing the relative axial movement of the corresponding head toward the inside of the tubular jacket so as to form a gas discharge passage between the jacket, the head and the corresponding sealing element.

Abstract: End member assemblies include an end member wall dimensioned for securement to a flexible spring member to at least partially define a spring chamber. A reservoir wall is supported on the end member wall and at least partially defines a reservoir chamber having a substantially-fixed volume. The reservoir wall includes at least one passage such that the reservoir chamber is disposed in fluid communication with the spring chamber. A passive control device is operatively associated with the passage such that under a first predetermined condition the passive control device is in a first operable condition in which the gas spring assembly has a first spring rate and such that under a second predetermined condition of use the passive control device is in a second operable condition in which the gas spring assembly has a second spring rate. Gas spring assemblies and suspension systems are also included.

Abstract: A die cushion-cum-slide cushion device selectively opens and closes a flow channel between a hydraulic pump/motor driven by a servo motor, and hydraulic cylinders that generate slide cushion force, or a flow channel between the hydraulic pump/motor, and hydraulic cylinders that generate die cushion force, by switching a selector valve. Before applying the slide cushion force is started, the servo motor is controlled to allow the hydraulic cylinders to generate required slide cushion force through a check valve. While the slide cushion force is applied, hydraulic circuits, each of which includes a logic valve, control pressure of the hydraulic cylinders, and hydraulic circuits, each of which includes the servo motor, control die cushion pressure of the hydraulic cylinders.

Abstract: A valve includes a case comprising a pin bore, a pin configured to move axially in the pin bore, wherein the pin seals the pin bore, a first channel in communication with the pin bore, a second channel in communication with the pin bore, wherein the second channel comprises a restrictor at a location offset from the first channel, a third channel in communication with the pin bore, wherein the third channel comprises a check valve, and the second channel and third channel are in communication with each other. The valve can be a miniature valve that is used in the control of hydraulic fluid in prosthesis, such as a prosthetic ankle joint.

Abstract: A slide cushion device includes: a hydraulic cylinder group integrally formed in a board provided immediately below a slide; a pressing member that is disposed in a recessed portion of an upper die that vertically moves together with the slide, in a vertically movable manner; a plurality of slide cushion pins that is provided in the pressing member and penetrates the upper die to be brought into contact with a piston member of the hydraulic cylinder group, wherein a number of the cushion pins is less than a number of hydraulic cylinders disposed in a plane of projection of the recessed portion; and a slide cushion hydraulic device that controls hydraulic pressure to be supplied to a compression chamber of the hydraulic cylinder with which a slide cushion pin is to be brought into contact.

Abstract: Disclosed herein is a battery case including a receiving part having an electrode assembly mounted therein, wherein the receiving part, which is formed by deforming a sheet type base material, is configured to have a stair-like structure in which at least one corner and/or surface forming a shape of the receiving part is deformed.

Abstract: There are provided a die cushion force control method and a die cushion device that can improve response delay of die cushion force without changing die cushion waiting position upward. In the die cushion force control method, a servo motor is driven according to a die cushion force command B previously set and the die cushion force is generated on the cushion pad. The die cushion force control method includes a step of allowing the cushion pad to wait in a predetermined die cushion waiting position at which a die cushion force action will start, and a preliminary pressurization step of outputting the die cushion force command B and preliminary applying pressure to the cushion pad before a slide of a press machine reaches the die cushion waiting position.

Abstract: A gas-operated spring with overtravel safety device, comprising: a tubular containment jacket, an end face, an opposite annular portion for closing the tubular jacket and for the passage of a piston rod, a piston rod arranged so as to pass through the annular portion, a chamber for pressurized gas being defined between the tubular jacket, the end face, the annular portion and the piston rod, the gas-operated spring comprising elements for clearly indicating that overtravel for the piston rod has occurred.

Abstract: A piston rod housing assembly for a gas spring includes a piston rod housing having an interior end, an exterior end axially spaced from the interior end, and an overtravel pressure relief passage extending through the piston rod housing and intersecting the exterior end.

Abstract: A device (1) for checking the state of charge of a gas spring (100), comprises: a supporting structure (2) equipped with connecting means (3) adapted to be reversibly connected to a gas spring (100); a plunger (4) slidably received, at least partly, in the supporting structure and having a first end (4b) adapted to interact, in conditions of use, with a charging valve of a gas spring, the plunger having a second end which has an abutment surface (4d); pushing means (6) operating on the abutment surface (4d) of the plunger (4) to apply a measured thrust on the plunger (4) such as to induce the displacement thereof; a position indicator (5) operatively associated with the plunger (4) and configured to represent the position of the plunger relative to a reference element (7). Also described is a method for checking the state of charge of a gas spring (100).

Abstract: A piston rod housing assembly for a gas spring includes a piston rod housing having an interior end, an exterior end axially spaced from the interior end, and an overtravel pressure relief passage extending axially through the piston rod housing and intersecting the exterior end. The assembly also includes an overtravel pressure relief member carried in the overtravel pressure relief passage and having an exterior end that projects axially beyond the piston rod housing.

Abstract: A gas spring for forming equipment. A casing includes an axially extending side wall, an open end, a transversely extending closed end wall axially spaced from the open end, and a pressure chamber established in part by the side and end walls to receive a gas under pressure. A piston rod is received at least partially in the casing for reciprocation between extended and retracted positions. A piston rod housing is received at least in part in the casing between the piston rod and the casing. An overtravel pressure relief feature includes a vent path that is disposed between the pressure chamber and the outside of the gas spring and that includes a vent passage through the side wall of the casing and a seal that sealingly interrupts the vent path, wherein displacement of the housing into the casing results in opening of the vent path.

Abstract: A piston rod housing assembly for a gas spring includes a piston rod housing having an interior end, an exterior end axially spaced from the interior end, and an overtravel pressure relief passage extending through the piston rod housing and intersecting the exterior end.

Abstract: An air dampening assembly for an electronic device comprises a base member. A first piston housing is disposed on the base member. A second piston housing is disposed on the based member opposite the first piston housing. A sliding member is disposed between the first and second piston housing. A first piston is disposed on a first elongated member of the sliding member. The first piston housing is configured to receive the first piston. A second piston is disposed on a second elongated member of the sliding member. The second piston housing is configured to receive the second piston.

Abstract: Described is a compensator (1) for unbalanced compression forces for press machines (100), comprising: a first body (20) having a first concave coupling surface (21) and a first end portion (22) opposite the first coupling surface (21); a second body (30) having a second convex coupling surface (31) and a second end portion (32) opposite the second coupling surface (31), the first (21) and second (31) coupling surfaces being geometrically coupled to each other in such a way as to allow a relative rotational movement between the first body (20) and the second body (30). More specifically, an end portion (22, 32) of at least one of the bodies (20, 30) is configured for being fixed to a structural element (101) of a press machine (100), the end portion (32, 22) of the other body (30, 20) being configured for forming an abutment surface designed to interact, in use, with a free end (402) of a stem (401) of a gas cylinder (400) of a press machine.

Abstract: An energy absorbing and transmitting material comprising a framework of interconnected units comprising at least one unit having a base and a protrusion or cone extending from the base along an axis, and at least one connecting member or rod that connects the unit to at least one adjacent unit, the connecting members extending substantially perpendicular to the axis of the unit from the base, where the framework is comprised of a single elastic material throughout, or configured so that when the framework is perturbed by tilting the unit towards the adjacent unit, the adjacent unit is tilted towards the unit.

Abstract: A gas spring includes a fill valve, and a rupture disc carried by the fill valve. An overpressure relief and fill valve assembly includes a valve housing with a valve passage, the fill valve carried by the valve housing and including a valve stem extending into the valve passage and an overpressure relief passage extending through the fill valve, and a rupture disc carried by the fill valve in communication with the overpressure relief passage. A gas spring may include the valve assembly therein.

Abstract: An overpressure relief plug including a rupture disc and engaging a fill valve in series downstream fluid communication with respect thereto. A gas spring may include a fill port, and the overpressure relief plug and the fill valve in the fill port.

Abstract: The invention relates to a hydro-pneumatic piston accumulator (1), particularly for vehicle suspension systems, consisting of an accumulator housing (2) and a separating piston (6), which is disposed free-floating inside the accumulator housing in a displaceable manner in the direction of the movement axis (4). The separating piston separates an accumulator area (8) for a hydraulic medium from a pressure area (10) that is filled or is to be filled with a compressible medium, and is guided with an interior guide opening (30) on an elongated guide element (32), which is axially fixed within the accumulator housing (2).

Abstract: An air damper is provided which can exhibit an appropriate braking force in accordance with an input load. There is provided an air damper including: a tubular cylinder 1 in which both end portions are opened; a piston 2 which moves within the cylinder 1; and a cap 3 which closes a one-end opening of the cylinder 1, wherein the cylinder 1 has an annular seal surface 4 formed on a circumferential surface of the one-end opening, wherein the cap is mounted on the one-end opening side of the cylinder 1 so as to be moveable or deformable along an axial direction of the cylinder 1, wherein the cap is brought into contact with or separated from the seal surface 4 in accordance with a pressure change due to a movement of the piston 2 within the cylinder 1, and wherein a first orifice 14 is opened in a base plate 12 of the cap, characterized in that: a second orifice having an inlet area smaller than the first orifice is defined between the cap 3 and the cylinder 1 during an operation of the first orifice 14.

Abstract: A gas spring for forming equipment, a piston rod for the gas spring, and a shock collar for the gas spring carried by the piston rod. The shock collar may be resiliently flexible, and plastically deformable so as to at least partially collapse, and the piston rod may include features to disrupt a gas spring seal upon at least partial collapse of the shock collar.

Abstract: A delay return gas spring including a piston at least partially received in a cylinder for reciprocation between extended and compressed positions over a cycle including a compression stroke and a return stroke. A seal disposed between the cylinder and the piston separates a primary chamber on one side of the seal from a secondary chamber on another side of the seal during a portion of the cycle. A passage communicates with the secondary chamber and with the primary chamber. The seal is relatively movable between an open position permitting free flow of gas through the passage to a closed position at least partially restricting gas flow through the passage so as to permit gas in the secondary chamber to be compressed in response to movement of the piston toward its extended position, thereby reducing a net return force on the piston and decreasing a velocity of the piston.

Abstract: In the die cushion device, a shock absorber device relieves shock between a cushion pad and a support section. The shock absorber device includes a damping section and an elastic section. The damping section generates reaction force in accordance with the relative speed of the cushion pad with respect to the support section. The elastic section generates reaction force in accordance with the relative displacement of the cushion pad with respect to the support section. The controller section controls a servomotor so that a speed difference between the speed of the slide member and the speed of the support section is set to be a predetermined target speed difference value that changes over time.

Abstract: In at least one embodiment, a gas spring includes a casing having an inner surface defining in part a gas chamber, a piston rod and a seal. The piston rod is received at least partially in the casing for reciprocation along an axis between extended and retracted positions. The piston rod has an internal cavity defining a hollow space, a stop and a rod guide disposed adjacent to the inner surface of the casing to guide the reciprocation of the piston rod at least in part. The seal generally is provided between the piston rod and the casing to prevent gas leakage from the gas chamber.

Abstract: A shock absorber includes a sleeve, a piston accomplishing forward and reverse travels therein, a rod, a piston cap, a rod cap including an orifice and a rod seal mounted therein. The rod seal defines a front face facing the piston and a rear face being opposite to the front face. The rod includes at least two rod regions including annular humps. The front and rear faces operatively interact with the annular humps during the forward and reverse travels, such that the interaction causes deformations of the rod seal thereby cushioning impacts and reducing overloads of the shock absorber. An embodiment of the shock absorber further includes two annular humps represented by a first annular hump, having a first maximal diameter, and a second annular hump, having a second maximal diameter, while the first maximal diameter is greater than the second maximal diameter, preferably by 3-10 micrometers.

Abstract: A press cushion (7, 17, 27) for a hydraulic press (1) including a first layer (9, 19, 39) which is impermeable to fluids and includes an elastomeric material and fibers connected therewith; a second layer (10, 20, 40) connected with the first layer (9, 19, 39), wherein the second layer is also impermeable to fluids, wherein the first layer (9, 19, 39) is provided with a plurality of channels (15, 22, 28, 36) on its side oriented towards the second layer (10, 20, 40), wherein the channels include a material that is flow-capable at least at the operating temperature of the press (1). Additionally the channels (15) are closed fluid tight at least through the second layer (10, 20, 40).

Abstract: A combination oil/gas spring includes a first hollow casing, a piston capable of fluid-tightly sliding within the casing, a rod connected rigidly with an end portion thereof to a central portion of the piston, a first chamber containing an actuating rod provided inside the casing, a second sealed chamber provided within the same casing on the opposite side of the piston, a mass of hydraulic fluid filling the second sealed chamber, a second hollow casing and a respective second piston provided to slide therewithin, a first conduit connecting the interior of the second sealed chamber with the interior of the second hollow casing, a first valve connected to the first conduit and adapted to selectively open and close it, a second conduit being provided to connect an expansion vessel to the first conduit at a position upstream of the first valve, and a second valve being provided on the second conduit.

Abstract: A device for the production and/or machining of parts, in particular for the production of stampings, by at least one die which is capable of being put under pressure and/or force, and which has at least one plate and one die element, the die element being supported in the plate against pressure elements via a resilient element.

Abstract: A high-pressure, inert gas cushion assembly for the ram or bolster of a metal stamping press includes a manifold having fluid-flow passages defined therein, along with a plurality of cylinder mounting locations each in communication with at least one of the fluid-flow passages. A plurality of cushion cylinders are located respectively in the cylinder mounting locations. Each cylinder includes a body having an inner wall that defines a bore of diameter D. A piston is located in the bore and includes opposite inner and outer faces, wherein the outer face is oriented outwardly relative to the bore and manifold. A fluid seal is supported on the piston and is slidably engaged with the wall defining the bore. One or more bearings are supported on the piston and slidably engaged with the inner wall that defines the bore. The bearing(s) support the piston slidably in the bore for reciprocal sliding movement between extended and retracted positions.

Abstract: A gas spring assembly that is suitable for use on a vehicle suspension system includes a first end member and a second end member that is spaced from the first end member. A flexible wall is secured between the first and second end members and at least partially defines a first gas chamber therebetween. A confinement at least partially forms a second gas chamber that is in communication with the first gas chamber. A porous flow restrictor is operatively disposed between the gas chambers. A suspension system including such a gas spring assembly as well as a method is also included.

Abstract: A die cushion device is comprised of die cushion modules which are independently movable and unitized. The individual die cushion modules are provided with a cushion pad, a servomotor, a power transmission mechanism, a power conversion mechanism and a guide member. By configuring in this way, the design of the die cushion is facilitated, a drive mechanism of the die cushion becomes compact, and the number of types of parts used is decreased.

Abstract: The present invention relates to an arrangement in an energy-accumulating piston-cylinder device (1, 2) having a piston (2) and a cylindrical casing (1). The invention is characterized by an openable safety valve (1) arranged in the piston (2) and/or a discharge duct (11) together with an element (8; 17) arranged on the cylindrical casing (1) or the safety valve (10) and in the cylinder chamber, which element is designed, in the event of the piston (2) being inserted into the cylinder chamber by more than a predetermined distance, to act upon the safety valve/the discharge duct (10, 11) in order to expose the said duct (11), permitting a discharge of the pressure in the cylinder chamber.

Abstract: The invention relates to an arrangement in a pressing tool for braking the return movement of pistons/piston rods (D1) of gas-filled springs (D) and thereby also of a sheet metal holder (B) supported thereon after pressing has been performed. The invention is characterised in that each gas-filled spring device (D) is designed with a separate brake cylinder part (E) and brake piston part (F), in which the brake cylinder part (E) is situated adjoining the outer end of the gas-filled spring (D) and in which the brake piston part (F) is situated adjoining the inner end of the piston rod (D1).

Abstract: A high-pressure, inert gas cushion assembly for the ram or bolster of a metal stamping press includes a manifold having fluid-flow passages defined therein, along with a plurality of cylinder mounting locations each in communication with at least one of the fluid-flow passages. A plurality of cushion cylinders are located respectively in the cylinder mounting locations. Each cylinder includes a body having an inner wall that defines a bore of diameter D. A piston is located in the bore and includes opposite inner and outer faces, wherein the outer face is oriented outwardly relative to the bore and manifold. A fluid seal is supported on the piston and is slidably engaged with the wall defining the bore. One or more bearings are supported on the piston and slidably engaged with the inner wall that defines the bore. The bearing(s) support the piston slidably in the bore for reciprocal sliding movement between extended and retracted positions.

Abstract: A method and an arrangement in an energy-accumulating piston-cylinder arrangement (A) has a piston/piston rod part (2), guide/end (3) and tubular casing (1). The casing (1) is provided with a fracture or sprain mark (7) in order to initiate a controlled deformation of the casing in the event of a load that produces a stress in excess of a sprain or fracture limit, or of repeated cyclical stressing that gives rise to material fatigue, so that an excess pressure in the arrangement (A) is discharged past the deformed casing.

Abstract: After molding is started, a large reaction force is obtained by compressing the air within a lower chamber by a piston while maintained in a sealing state. At an intermediate time of the molding, a small reaction force is obtained by communicating the upper and lower chambers with each other by a switching portion of a spool. At a final time of the molding, a large reaction force is again obtained by interrupting a flow path between the upper and lower chambers. The die cushion ability can be mechanically switched in association with the stroke of the piston, the die cushion device can be set such that no time lag is easily caused at a switching time, and the die cushion ability can be instantly switched.

Abstract: A gas spring comprising a cylinder body filled with compressed gas and an upright rod passing through a rod side end wall member of the cylinder body. By supporting a main shaft unit with the gas spring, the load on a vertical displacement mechanism is reduced. A pair of upper and lower ring-shaped seal members, which seal between the rod end wall member and the rod, are provided inside the rod wall member. Ring-shaped oil filling chambers are formed in between the ring-shaped seal members and between the rod end wall member and the rod. An oil filling mechanism fills the oil filling chambers with lubrication oil.

Abstract: The present invention generally relates to devices and methods for absorbing kinetic energy. In particular, the present device is well suited for use in an automobile door, where it can be positioned for the purpose of absorbing the energy of a side-impact collision. In one embodiment, the device includes a first mass, a shell, and a plate, with the shell being disposed between the mass and plate. Both the first mass and shell are preferably constructed from deformable materials, allowing them to absorb energy during an impact. By absorbing the energy through deformation, the present device reduces the amount of energy that is transmitted through the door and thus reduces the amount of energy that may be transmitted to the occupants of the vehicle.

Abstract: The invention relates to an arrangement in a pressing tool for braking the return movement of pistons/piston rods (D1) of gas-filled springs (D) and thereby also of a sheet metal holder (B) supported thereon after pressing has been performed. The invention is characterised in that each gas-filled spring device (D) is designed with a separate brake cylinder part (E) and brake piston part (F), in which the brake cylinder pail (E) is situated adjoining the outer end of the gas-filled spring (D) and in which the brake piston part (F) is situated adjoining the inner end of the piston rod (D1).

Abstract: The present invention relates to an arrangement in an energy-accumulating piston-cylinder device (1, 2) having a piston (2) and a cylindrical casing (1). The invention is characterised by an openable safety valve (10) arranged in the piston (2) and/or a discharge duct (11) together with an element (8; 17) arranged on the cylindrical casing (1) or the safety valve (10) and in the cylinder chamber, which element is designed, in the event of the piston (2) being inserted into the cylinder chamber by more than a predetermined distance, to act upon the safety valve/the discharge duct (10, 11) in order to expose the said duct (11), permitting a discharge of the pressure in the cylinder chamber.

Abstract: A cushion assembly includes a lower end wall which is at least partially enclosed by a tubular cylindrical outer wall. An upper end wall is also partially enclosed by the outer wall. A tubular cylindrical inner wall extends between recesses in the lower end wall and the upper end wall. A piston is disposed within the inner wall and is movable along the inner wall toward the upper end wall under the influence of gas pressure. The piston is movable along the inner wall toward the lower end wall of the influence of force applied against the piston during operation of a press. A passage is formed between an end portion of the inner wall and the lower end wall to conduct a flow of lubrication liquid and gas to lubricate the piston.

Abstract: A hydraulic drawing system for a press is provided for controlling a blank holder. The blank holder can be moved by at least one hydraulic cylinder-piston unit which has at least one pressure chamber. By way of a connection line, the pressure chamber is connected directly with a control block provided for controlling the movements of the at least one cylinder-piston unit. At least one storage element for storing pressure for the at least one cylinder-piston unit is connected by way of a connection line with the control block and, by way of another connection line at least one valve device is connected with the control block. The connection lines extend in each case at least approximately completely within the respective components.

Abstract: A fluid pressure cylinder with pressure intensifying function, has an oil-filled hydraulic pressure cylinder which is filled with oil and tightly sealed. A gas-filled gas spring is charged with gas and tightly sealed. By means of gas spring, oil in oil chamber of hydraulic pressure cylinder is pressurized to a pressure level higher than the gas pressure in gas actuating chamber of gas spring. This results in a strong pushing force being generated via output piston of hydraulic pressure cylinder.

Abstract: A sleeve-type gas spring for a turret indexing press has an annular piston operably associated with a punch tool to reciprocate therewith and defining in part an annular gas chamber constructed to receive a gas under pressure. As the punch tool and piston are driven to their extended position by a press ram or some such other power device, the volume of the gas chamber decreases thereby increasing the pressure within the gas chamber such that when the ram is retracted, the pressure of the gas acting on the piston displaces the piston and the punch tool to their retracted positions. The force acting to retract the piston and the punch is dependent on the initial pressure of the gas within the gas chamber and the change in volume of the gas chamber as the punch tool and piston are extended.