Abstract: The present invention relates to a spring system for bicycles having a first load-applying segment (22) and a second load-applying segment (26) as well as at least one positive spring (14) and at least one negative spring (12, 88) arranged to be effectively operable between said first and said second load-applying segment (26).

Abstract: A spring having a main gas chamber, a secondary gas chamber and sealing surfaces which, during a portion of the stroke of the piston rod, define a gas tight seal between them to provide two separate gas chambers each providing a force acting on the piston rod in opposed directions to each other to reduce the net force on the piston rod. When the piston rod is near its fully extended position the sealing surfaces provide the gas tight seal and the net force on the piston rod is minimal and in the direction to move the piston rod to its fully extended position. Thus, until the cooperating surfaces are displaced to terminate the gas tight seal, only a slight force is required to initially move the piston rod from its fully extended position. This greatly reduces the impulse or impact force imparted to a press ram upon initial actuation of the fully extended piston rod. A second seal assembly may also be provided which controls the rate at which the piston rod assembly returns to its fully extended position.

Abstract: Fluid pressure cylinder 1 with pressure intensifying function, consisting of oil-filled hydraulic pressure cylinder 2 which is filled with oil L and tightly sealed and gas-filled gas spring 3 which is charged with gas G and tightly sealed, wherein, by means of gas spring 3, oil L in oil chamber 11 of hydraulic pressure cylinder 2 is pressurized to a pressure level higher than the gas pressure in gas actuating chamber 21 of gas spring 3 and a strong pushing force is generated via output piston 12 of hydraulic pressure cylinder 2.

Abstract: This invention relates to a hydraulic force modulator used in a power press to provide a predetermined force with a defined force applied by a ram of the press at defined incremental positions of the ram relative to a stationary part of the press. A moveable plate moves relative to a base plate. A resilient pneumatic bellows has one end sealingly mounted on the moveable plate. The resilient pneumatic bellows has an opposite end sealingly mounted on the base plate. A vessel is connected on one of the plates. A metering cylinder is mounted on the same plate as the vessel and is positioned within the vessel. A piston assembly is mounted in the metering cylinder. A piston rod has one end connected to the piston assembly and the opposite end connected to the other of the plates.

Abstract: An annular bellows unit for replacing a vehicle suspension coil spring that encloses a shock absorber or hydraulic actuator includes annular second flange members that are sealingly connected at opposite ends of respective inner and outer bellows members to form a closed chamber, and a fill port in one of the flange members for pressurizing the chamber.

Abstract: An energy dissipation system for limiting forces applied to object; includes a piston rod that extends out of a pneumatic cylinder which contacts the object, the piston rod is forced from its initial position against a return spring and air is forced into an air line. The force transmitted to the object is consumed by an energy transformation device that responds to the air in the air line. [One such energy transformation device as an air accumulator, which is coupled to the air line trough a check valve. An orifice or release valve, releases air up a predetermined flow rate so that the linear motion of the protected object is transformed into work, which is dissipated.] [Another] The energy transformation device consists of an air-driven motor coupled to a heavy flywheel [through] that is driven by the motor.

Abstract: A gas spring includes an outer tube; a base plate; a head plate; an inner tube mounted to extend between the head plate and the base plate; a piston/rod assembly mounted to reciprocate vertically in the inner tube between a retracted, compressed position and an extended, rest position; a valve ring coaxially mounted around the rod to reciprocate between the main piston and head plate; a primary gas chamber; a relief chamber; seals for preventing fluid flow from the primary and relief chambers; a passageway providing communication between the primary gas chamber and relief chamber; and, valve apparatus for controlling fluid flow between the primary and relief chambers. The valve apparatus operates to open and close the fluid flow as a function of the position and direction of travel of the piston/rod assembly.

Abstract: An annular bellows unit for replacing a vehicle suspension coil spring that encloses a shock absorber or hydraulic actuator includes annular second flange members that are sealingly connected at opposite ends of respective inner and outer bellows members to form a closed chamber, and a fill port in one of the flange members for pressurizing the chamber.

Abstract: A fluid spring assembly. The spring assembly preferably includes a body that slidably supports a piston that is attached to a piston rod. The piston serves to define a fluid chamber within the body that is charged with a pressurized fluid medium. The piston is retained within the body by a rigid retainer member. A biasing member is provided between the retaining member and the piston for resisting the force generated by the fluid medium within the fluid chamber.

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.

Abstract: This invention relates to a hydraulic force modulator used in a power press to provide a predetermined force with a defined force applied by a ram of the press at defined incremental positions of the ram relative to a stationary part of the press. A moveable plate moves relative to a base plate. A resilient pneumatic bellows has one end sealingly mounted on the moveable plate. The resilient pneumatic bellows has an opposite end sealingly mounted on the base plate. A vessel is connected on one of the plates. A metering cylinder is mounted on the same plate as the vessel and is positioned within the vessel. A piston assembly is mounted in the metering cylinder. A piston rod has one end connected to the piston assembly and the opposite end connected to the other of the plates.

Abstract: A gas spring with a first gas chamber communicated with a second gas chamber through a calibrated orifice to control the rate of return of gas from the first chamber to the second chamber to thereby control the rate at which a piston rod of the cylinder returns to its extended position. Desirably, the rate of return of the piston rod to its extended position can be made slow enough to prevent damage to a die stamped part as the gas spring lifts the part from a lower die half. The gas spring composite shell is preferably formed of and contains materials which are highly thermally conductive and define the return passage to prevent the gas spring from becoming overheated and to permit an increased number of cycles to be completed in a given period of time.

Abstract: A plurality of die cylinders adapted to contain gas under pressure are mounted on a manifold. Each cylinder comprising a cylinder body having an axially inner cylinder portion and an axially outer cylinder portion. A piston has an axially inner end portion extending into the inner cylinder portion and an axially outer end portion surrounded by the outer cylinder portion. A seal is provided between the inner end portion of the piston and the inner cylinder portion. There is a removable sealing cartridge between the outer end portion of the piston and the outer cylinder portion. A snap ring removably retains the cartridge on a shoulder between the inner and outer cylinder portions. The piston is capable of full axially outward retraction and separation from the cylinder when the cartridge is removed. The cylinder is free of any obstruction which would interfere with the axially outward retraction and separation of the piston when the cartridge is removed.

Abstract: A die stamping system in which an upper die moves downwardly toward and upward away from a lower die to stamp a workpiece, and in which a portion of the lower die is supported by at least one gas cylinder coupled to gas under pressure to cushion downward movement of the lower die portion and delay upward movement of the lower die portion. Each gas cylinder has a piston reciprocable within a vertical cylinder body. The piston has an upwardly extending piston rod for engaging the lower die portion. The cylinder body has a lower portion beneath the piston connected to the gas under pressure. A first passage connects an upper portion of the cylinder body above the piston to the lower portion of the cylinder body beneath the piston. A second passage connects the lower portion of the cylinder body to a tank. A third passage connects the upper portion of the cylinder body to the tank. First, second and third valves in the respective first, second and third passages control gas flow.

Abstract: A draw die operable within a straightside press includes a lower die shoe with a lower die; pressurized lift cylinders each having an upwardly extending piston rod and an axial resistance to compression; a generally ring-shaped cushion defining a central hole and a plurality of lock beads extending upwardly in spaced-apart relation surrounding the central hole, wherein the cushion surrounds the punch, is sized and configured to support a blank atop the beads and over the punch for draw forming the blank over the punch, and is supported by the lift cylinders; a plurality of cushion units held by the shoe and each having an upwardly extending piston rod and an axial resistance to compression; an upper die defining a second stamping shape which mates with the first stamping shape; a plurality of hydraulic shock absorbers held by the upper die and having an axial resistance to compression and a piston rod that extends downwardly toward the cushion.

Abstract: The invention relates to an arrangement for a gas spring. The arrangement comprises a cylinder (1). At its one end, this is delimited by a fixed end wall (2), and at its other end there is a first guide (3) sealed against the inner wall of the cylinder (1) and against a piston rod (4) capable of axial movement within the cylinder (1). The piston rod (4) has a second guide (8) mounted in such a way as to be capable of sliding against the inner wall. An annular piston (9) sealed against the inner wall and against the piston rod (4) is mounted on the piston rod (4) between the guides (3; 8) in such a way that it is free to slide. This divides the inner space of the cylinder (1) into a first and a second part space (12; 13). In an initial position, in which the gas spring is unaffected, there is present in the first part space (12) a pressure which is greater than the pressure present in the second part space (13).

Abstract: A self-lubricating cylinder assembly for use in a press operable in an upright orientation and in an inverted orientation. The cylinder assembly contains a working fluid under pressure and lubricating oil. The cylinder assembly includes a cylinder body that has sidewalls that terminate in an opening at a first end and an end wall at a second end. The cylinder assembly further includes an interior wall assembly that connects to the cylinder body and has walls that extend within the cylinder body to the end wall. The wall assembly walls are preferably formed of a cylinder liner in connection with an insert. The cylinder liner has a piston mounted for reciprocal motion therebetween. A variable volume wall assembly space is defined as a space between the piston, the wall assembly walls and the housing end wall. An expansion reservoir is defined as a space between the side walls of the cylinder body, the wall assembly walls and the cylinder body end wall.

Abstract: A safety circuit for a press die cushion wherein the press die cushion has a pad that is resiliently supported by a cushion cylinder which is supplied with a pilot pressure via an air delivery circuit, and wherein the press die cushion has a locking circuit for locking the pad. The safety circuit includes a first electromagnetic valve which is electrically switchable in two directions for controlling delivery of the pilot pressure to an air supply valve in the air delivery circuit to the cushion cylinder, and for controlling the air supply valve in order to lift the pad up and down. An on and off valve is disposed in a pilot pressure delivery passage of the air delivery circuit, and is opened when the pad lies in a vicinity of a lower limit position. A second electromagnetic valve is connected to the on and off valve.

Abstract: A balancing apparatus for a pressing machine, including a force generating device for generating a force during a pressing operation on a blank, and a plurality of balancing hydraulic cylinders which have respective oil chambers communicating with each other and which include respective pistons that are moved to neutral positions thereof during the pressing operation, for evenly distributing said force, and where a discharge control device is connected to a connecting passage connecting the oil chambers of the balancing hydraulic cylinders to each other, so that the discharge control device inhibits a discharge flow of a working fluid from the hydraulic cylinders and thereby holding the pistons of all of the hydraulic cylinders at upper stroke ends thereof, prior to the pressing operation, and permits the discharge flow of the working fluid to thereby permit the pistons to be moved to the neutral positions during the pressing operation.

Abstract: A pneumatic spring for damping movement of a machine part having a guide shaft for performing a stroke. The spring includes a housing containing gas. The housing is formed as a stationary body with a central opening adapted to accommodate the guide shaft. Several cylindrical bores are formed within the stationary body. A piston is peripherally guided within each cylindrical bore. Each piston has a center point located on a circle which is concentrically oriented with the central opening. The pistons contact the machine part with an upper support end so that all the pistons jointly perform a stroke with the machine part. Alternatively, the cylindrical bores are. selectively equipped with sealing disks instead of pistons, to adjust the resistance force characteristic of the spring.

Abstract: Pressing method and system wherein a drawing operation on blank is performed by die and punch while the blank is held between the die and a pressure ring by a blank holding force which is generated based on a movement resistance of the cushion platen and which is transmitted to the pressure ring through first cylinders and cushion pins, and wherein during a downward movement of the die toward the pressure ring, the cushion platen is moved down against the movement resistance before holding of the blank between the die and the pressure ring, by cooperation of second cylinders disposed on the cushion platen and communicating with the first cylinders, and shock absorbers disposed between the second cylinders and the die or a member moving with the die, so that the speed at which the die collides with the pressure ring is reduced by the downward movement of the pressure ring with the cushion platen.

Abstract: A gas spring apparatus includes first and second cylinders each closed at both ends by end walls, first and second pistons each capable of axial displacement being disposed inside a fluid-filled inner space of the cylinders, the first piston dividing the first cylinder into two sub-spaces, the second piston dividing the second cylinder into two cylindrical chamber, first and second piston rods each of, which is connected to the corresponding piston, being mounted in a sliding and sealing fashion in one end wall, and a plurality of valves selectively communicating among two sub-spaces and two cylindrical chambers to decrease pressure inside one of the sub-spaces so as to cause the first piston to be locked for a predetermined period of time, and to cause the first and second pistons to move upwards and back to an initial position of each of the first and second pistons after a predetermined delay. The valves are openable and closable which are controlled by a control device.

Abstract: A metal working press employs a self-contained liquid spring adapted for the clamping of metal blanks during the performance of punching, cutting or forming operations thereon. The liquid spring comprises a fluid cylinder vessel filled with a pressurized compressible liquid in which is mounted a piston. The piston includes a piston head and a piston rod, which extends outside of the cylinder vessel through an annular seal at one end of the cylinder vessel. The piston head may have holes therein to permit the liquid to flow through the head during compression of the liquid in response to a force applied to the rod. The piston may include a liquid chamber communicating with the interior of the fluid cylinder vessel and extending through the piston head and along the shaft of the piston rod.

Abstract: The invention relates to a drive for a press, in particular for a sheet metal forming press, the press including a press ram which can be moved up and down and a hydraulic movable counter support. The counter support can be moved in a forward stroke in the direction towards the press ram via at least one hydraulic cylinder by a first hydrostatic machine, and in a return stroke by the press ram. In known presses, during the return stroke of the counter support, the pressure medium is displaced from the hydraulic cylinder while a predetermined pressure is maintained by means of a pressure relief valve (pressure limiting valve) or a throttle valve (flow control valve). The balance sheet of energy of such a drive of such a press is to be improved. This is achieved by providing that the first hydrostatic machine is a pressure controlled machine, preferably an axial piston machine. Preferably, the axial piston machine can be swiveled in both directions, i.e. pivoted towards both sides.

Abstract: A gas spring with an elongate tubular casing having a chamber for containing a gas under pressure therein. The casing has an opening at one end and an annular groove around the outer circumference. A piston rod projects from the casing through the opening and is connected to a piston disposed within the chamber for compressing the gas therein. A mounting sleeve is telescoped over the casing and has exterior threads thereon. The sleeve has an internal annular groove which coincides with the groove in the casing forming a passage between the sleeve and the casing. The sleeve is secured to the casing by a lock ring formed in the passage by injecting a resin into the passage and allowing it to cool and solidify. Holes are formed through the sleeve opening into the passage. Some permit resin to be injected into the passage through the holes and some permit resin to flow from the passage into the holes.

Abstract: A shock-absorbing strut in which fluid passages extend through the strut to communicate with a hydraulic wheel drive of the wheel assembly to which a movable part of the strut is affixed. Telescoping connectors are provided between the outer guide housing affixed to the vehicle frame and a revolving joint in the axially movable support element and compensating cylinders are provided to balance the hydraulic pressure on the revolving joint resulting from the pressure in the telescoping connectors of the oil feed to the wheel drive.

Abstract: A gas cylinder element having a replenishable lubrication means provided in the piston rod guide bushing. The gas cylinder element has an extended life expectancy and reduced manufacturing cost.

Abstract: Disclosed is a spring device which, during use in co-action with a deep-drawing device, is capable of causing the blank-holder pressure to decrease in proportion to the remaining material. The spring device holds substantially constant the blank-holder force per unit of surface area on the non-deformed material and is considered a "degressive" spring wherein the reaction force exerted by the spring decreases as the displacement between the ends of the spring increases.

Abstract: The present invention relates to gas cylinder springs and, more particularly, to gas cylinder springs which receive gas from a manifold into which the gas cylinders are threaded. The invention specifically relates to a way of automatically and in a nonmechanical manner expel atmospheric pressure from the gas spring. The piston rod of the gas spring is tapered slightly to provide a pocket into which atmospheric pressure can collect and be expelled around the gas spring seals on each stroke of the piston rod.

Abstract: A self-contained gas spring that has low heat generation characteristics and is easy to manufacture and maintain. The spring includes a bearing and seal assembly that is easy to remove from the cylinder body of the spring. The assembly includes an annular bearing for guiding the piston rod, the bearing is press fit within a bearing cap and, an end cap threaded in to the cylinder body. The end cap includes an annular seal surrounding and tightly engaging the piston rod of the gas spring. The end cap engages the bearing cap when the end cap is fully threaded into the cylinder body to retain the bearing cap within the cylinder body. The seal is formed of two materials, one very flexible, the other very rigid. The gas spring also has a unique piston head that has a hexagonal periphery with upwardly angled sides.

Abstract: The invention consists on the one hand of a cylinder (2) closed at its ends by means of end walls (4, 5) and on the other hand of an enclosed space (10). With a piston (3) capable of axial displacement, the cylinder (2) is divided into two sub-spaces (6, 7). The space (10) communicates with the aforementioned first sub-space (6) via a first openable and closable valve (11a). The second sub-space (7) communicates with the aforementioned first sub-space (6) via a second openable and closable valve (13a). A control device (12) actuates the openable and closeable valves (11a, 13a), so that the second valve (13a) is opened when a force (F) acting upon the end of the piston rod (8) has forced the piston (3) in a direction towards the first end wall (4) and into a predetermined position. The second valve (13a) is closed again once pressure equilibrium has been achieved between the sub-spaces (6, 7).

Abstract: A gas cylinder for use in die systems for forming lightweight parts. In one form, the cylinder forms a self contained gas spring which is interchangeable with a coil spring that is constructed such that it is not adversely affected by the deleterious effects of oil and other contaminants. The gas cylinder comprises a one-piece cylindrical upper body having a base wall and a peripheral wall and a hollow rod extending upwardly into the cylindrical body such that the upper body completely encircles and encloses the upper end of the rod. The rod has a base having an outer diameter greater than the diameter of the rod. The peripheral wall of the cylinder and the outer diameter of the base have substantially the same diameter such that the cylinder can be positioned in a recess of a press or die in place of a coil spring. The cylindrical body and rod include interengaging portions limiting axially outwardly movement of the cylinder relative to the rod.

Abstract: A filler valve and fitting for a gas spring. The filler valve has a body slidably received in a cavity in a housing and movable between a first sealed position for retaining gas within a gas chamber in the spring and a second position for bleeding gas from the chamber to relieve pressure within the chamber. For charging the chamber with gas, a core valve is carried by the body. Preferably, the housing has an exterior configuration and size of a standard flow-through type coupling having a pair of exteriorly threaded portions separated by a central portion with parallel flats constructed and arranged for engagement by a tool to install and remove the housing. The body has opposed effective areas with the effective area adjacent an inlet in the housing being greater than the effective area adjacent the outlet for enabling gas within the chamber to be compressed to a pressure much greater than the supply line pressure.

Abstract: An apparatus to cushion movement of a member in a machine includes a piston which divides a cylinder into upper and lower variable volume chambers. A body of lubricating liquid is held in a chamber in the piston. Lubricating liquid is conducted from the chamber in the piston to an annular space between upper and lower seals on a head portion of the piston. During reciprocation of the piston, the lubricating liquid engages the inner side surface of the cylinder. In addition, the lubricating liquid conducts heat away from the cylinder. Fluid pressure is applied against upper side surface of the body of lubricating liquid in the piston chamber by gas pressure conducted from a chamber of the cylinder. During assembly of the apparatus, the piston is inserted part way into the cylinder and a space between seals on the piston is partially filled with lubricating liquid. The piston, with the lubricating liquid between the seals, is fully inserted into the cylinder.

Abstract: A self contained gas spring comprising a cylindrical housing having a closed end, an open end and a cylindrical bore. A cylindrical sleeve extends into the bore of the housing. The sleeve has at least a portion thereof forming an internal cylindrical surface. A piston rod extends through an opening in the sleeve and has a piston contacting the cylindrical surface. A portion of the sleeve defines a first space between the sleeve and the bore of the housing. The first space communicates with a second space between the piston end of the piston rod and the closed end of the housing. A charging valve is provided in the closed end of said housing for charging the space at the piston end of said piston rod and the space between the sleeve and the housing with gas under pressure. A third axial space is provided between the cylindrical surface on the sleeve and the piston rod above the piston and is isolated from the first space and second space.

Abstract: A high pressure die cylinder and manifold system including a plurality of die cylinders mounted on a manifold. Each die cylinder includes a cylinder body in which a piston rod and a piston is positioned for limited relative movement with respect to the cylinder body. A cup shaped piston sealing ring is mounted on the cylinder body for engagement with the piston rod and a cup shaped sealing ring is mounted on the piston for engagement with the cylinder body. A lubricant metering ring is mounted on the piston intermediate the sealing rings and the piston has a lubricant chamber that communicates with circumferentially spaced openings in the lubricant metering ring for delivering lubricant to the exterior of the sealing ring.

Abstract: A hydraulic cushioning apparatus for a press having an upper and a lower die assembly (3, 9) for forming a sheet-like workpiece (6), including hydraulic cylinders (54) incorporated in one of the upper and lower die assemblies, and pressure pins (52) linked with the respective hydraulic cylinders. The pressure pins are reciprocable to apply a cushioning force (F) to the workpiece, in a pressing action of said die assemblies on the workpiece, so as to force the workpiece against the other die assembly. The apparatus is equipped with a hydraulic power supply device (72, 100, 117, 272) for delivering a pressurized fluid to the hydraulic cylinders (54). The power supply device is capable of changing an initial hydraulic pressure (P.sub.0) of the fluid to be applied to the hydraulic cylinders before the pressing action of said die assemblies.

Abstract: A gas spring assembly includes a cylindrical tube, a piston slidable within the tube and defining a gas pressure chamber, a rod extending from the piston through one end of the tube, and a seal assembly including an axially compressible, consumable seal for preventing escape of gas between the rod and the tube. A stop formed in the inner wall of the tube is adapted to engage the piston to limit the extension of the rod to a constant, maximum value, regardless of axial compression and consumption of the seal. The seal assembly is disposed between the stop and one end of the tube, opposite the piston, and includes gas passageway allowing pressurized gas to act on one end of the seal assembly to thereby bias the seal assembly toward one end of the tube.

Abstract: An apparatus and method for use in cushioning movement of a member in a press includes a cushion assembly having a piston and cylinder which are movable relative to each other against the influence of fluid pressure to cushion movement of the member. A flexible diaphragm retains a body of lubricant between an inner side of the diaphragm and the piston. The body of lubricant lubricates a seal between the piston and the cylinder. Fluid pressure is applied against the outer side of the diaphragm to oppose movement of the piston during operation of the press from the open condition to the closed condition. The piston is movable relative to the cylinder, under the influence of the fluid pressure applied against the outer side of the diaphragm and transmitted to the piston, during operation of the press from the closed condition to the open condition. The piston and diaphragm are spaced apart with the body of lubricant filling the space between the piston and diaphragm.

Abstract: A self contained gas spring which is interchangeable with a coil spring that is constructed such that it is not adversely affected by the deleterious effects of oil and other contaminants. The gas spring comprises a one-piece cylindrical upper body having a base wall and a peripheral wall and a rod extending upwardly into the cylindrical body such that the upper body completely encircles and encloses the upper end of the rod. The rod has a base and the outer diameter of the peripheral wall of the cylinder and the outer diameter of the base have substantially the same diameter such that the cylinder can be positioned in a recess of a press or die in place of a coil spring. The cylindrical body and rod include interengaging portions limiting axially outwardly movement of the cylinder relative to the rod.

Abstract: A self contained gas spring comprising a housing having a closed end and an open end, and a cylindrical bore. A cylindrical sleeve is inserted into the bore of the housing. The sleeve has at least a portion thereof forming an internal cylindrical surface. A piston rod has a piston within the cylindrical surface. The sleeve defines a space between the sleeve and the bore of the housing. This space communicates with the space of said cylindrical surface at the piston end of the piston rod. A charging valve is provided in the closed end of said housing for charging the space at the piston end of said piston rod and the space between the sleeve and the housing with gas under pressure. Preferably, the die cylinder includes sufficient volumetric space such that the pressures in the self contained gas spring do not increase substantially during the movement of the piston within the cylinder.

Abstract: An apparatus for scribing grain-oriented electrical steel strip has a movable die attached to a reciprocating drive and an opposite fixed die. A strip held between the two dies is scribed by the action of the movable die that is moved back and forth by the reciprocating drive. The fixed die positioned with the stroke of the movable die is supported by a plurality of cylinders connected to an accumulator whose pressure is preset to a level of the deformation resistance corresponding to the amount of deflection that varies with the depth of the impressions scribed on the strip.

Abstract: A drawing apparatus in drawing stages of a press, having a pressure cheek divided into segments, to the corner areas of which pressure cylinders are applied. The pressure cylinders are fixed to the press. Their piston rods, by way of pressure rods, act upon a liftable and lowerable console. At least one locking cylinder which is fixed to the frame is provided which, by way of a lift bridge, is applied to the console and, corresponding to the pressure which acts upon it, prevents an upward movement of the console and thus of the pressure cheek. The point in time of the stop stage in the upward-moving stage can be determined by the valve control of the pressure in the locking cylinders.

Abstract: A closed type cylinder unit, instead of the open-to-atmosphere type cylinder unit of conventional equipment forms part of the die cushion apparatus. Based on the principle that the die cushion capability by the closed type cylinder unit is determined by the differential pressure between the lower chamber pressure and the upper chamber pressure, the differential pressure is controlled in such manner that the lower chamber and the upper chamber communicate with each other through a check valve, which is opened when the differential pressure exceeds a preset differential pressure value. As the upper and lower chambers communicate through a shut-off valve, which hinders the excessive increase of the upper chamber pressure when the piston goes up. Further, the form of the check valve is changed for conveniently changing and adjusting the die cushion apparatus during press fabrication.

Abstract: A compressed gas and a liquid are contained in a cylinder. A liquid chamber containing the liquid and a gas chamber containing the gas are divided by a metallic bellows. The liquid chamber is situated on the side of an open end of the cylinder. A rod is inserted in the cylinder. A sealing assembly is provided at the open end of the cylinder. The sealing assembly has a bearing member at only one portion of the cylinder with respect to the axial direction thereof. A space extends throughout the circumference between the outer peripheral surface of the inner end of the rod and the inner peripheral surface of the cylinder. A seal device for sealing the liquid in the liquid chamber includes a seal ring intimately in contact with the outer peripheral surface of the rod and an elastomer ring provided on the outer peripheral surface side of the seal ring and capable of elastic deformation in the radial direction of the rod. The rod can swing within the range of an angle .theta.

Abstract: A gas spring comprising a cylindrical body having a base wall and an integral side wall with an open upper end defining a bore. The bore includes a lower cylindrical portion and an upper cylindrical portion of greater diameter than the lower cylindrical portion defining a shoulder. A piston of constant diameter is positioned in the bore and has a radial flange on its lower end with a wear bearing contacting the lower portion of the bore. An annular retainer is positioned on the shoulder and is adapted to be engaged by the flange on the piston. An annular end cap is threaded in the upper cylindrical portion of the bore and maintains the retainer against the shoulder. An annular lock nut is threaded in the upper portion of the bore and locks the end caps in position. Circumferentially spaced radial openings are provided adjacent the periphery of the lock nut for venting gas during disassembly if any gas remains. A charging valve and a rupture plug including pressure relief disc are provided in the base wall.

Abstract: An improved press assembly has upper and lower draw rings which grip a workpiece. During closing of the press assembly, an improved control assembly accelerates the lower draw ring to a first speed and then to a second speed before the upper and lower draw rings move together. Similarly, during opening of the press assembly, the control assembly decelerates the lower draw ring to a first speed and then decelerates the lower draw ring to a second speed prior to stopping of the lower draw ring. The control assembly includes a two stage piston and cylinder assembly. The piston and cylinder assembly includes an inner piston and a hollow outer piston which encloses the inner piston. The inner piston is engagable with a flange on the outer piston to move the outer piston with the inner piston.

Abstract: A die cushion device includes a cylinder having a closed one end and the other end with a through-hole. A push rod is inserted into the cylinder through the through-hole and is freely movable in the axial direction of the cylinder. The interior of the cylinder is partitioned by a bellows into a liquid chamber communicating with the through-hole and housing a part of the push rod, and a gas chamber located on the closed end side of the cylinder. Operation liquid is filled in the liquid chamber. Gas is sealed in the gas chamber and pressurizes, through the bellows and the liquid, the push rod in a direction of projecting from the cylinder.

Abstract: An improved seal arrangement is used in a cushion assembly of a press. The seal arrangement includes a high pressure piston seal assembly which is connected with a piston and is disposed in sealing engagement with a cylinder of the cushion assembly. The high pressure piston seal assembly blocks fluid flow between upper and lower variable volume chambers of the cushion assembly. A high pressure cylinder seal assembly is disposed in sealing engagement with a piston rod and the cylinder to block fluid flow from the upper variable volume chamber along the piston rod. An outer low pressure seal assembly is also provided between the piston rod and cylinder to block contaminants from entering the cylinder from the surrounding environment. A low pressure leak down chamber is provided between the high pressure cylinder seal assembly and the low pressure seal assembly.

Abstract: A press assembly is operable from the open condition to a closed condition to deform a workpiece. The press assembly is the operable from the closed condition to an open condition to facilitate removal of the deformed workpiece from the press assembly. During operation of the press assembly, the workpiece is held by upper and lower draw rings or members which apply pressure to opposite sides of the workpiece. A cushion assembly is operable to provide a yieldable force opposing movement of the draw rings. As the press is operated from the open condition to the closed condition, the lower draw ring is accelerated while the upper draw ring is spaced from the lower draw ring. This reduces shock loading on the press when the upper draw ring and workpiece subsequently impact against the lower draw ring to grip the workpiece.