Abstract: The present invention relates to improved gripper bushing assemblies for use with injection molds, molding machines and other devices. In a first embodiment, the gripper bushing assemblies include an elongated flexible gripping sleeve positioned about a column member such as a tiebar. The sleeve is secured to a member such as a moving platen and is used to clamp the platen to the tiebar in a desired location. The gripper bushing assemblies further include one or more spacers intermediate the sleeve and the platen. The spacers engage the sleeve via a mechanical interlock. The sleeve and spacer(s) are capable of accommodating tiebar stretching which may occur as a result of clamping forces being applied to the mold via the platen. In a second embodiment, the spacer(s) are omitted and the gripping sleeve has a male thread which engages a female thread on the platen.

Abstract: The hydraulic system comprises a 4/4-way valve, which is adapted to control the velocity of the mold-closing operation and the fluid pressure during said mold-closing movement and to assume three consecutive control positions, in each of which fluid pressure is applied to a stationary piston of an advance-retract cylinder from a first cylinder chamber, which is nearer to the mold. One of said control positions is a differential control position, in which pressure fluid displaced from the second cylinder chamber of said advance-retract cylinder, which second chamber is remote from the mold, is supplied to a pressure conduit through a branch passage, which includes a non-return valve. The differential control position is preceded and succeeded by a transitional control position, in which the pressure fluid displaced from the second cylinder chamber is returned through the 4/4-way valve to a reservoir.

Abstract: A mold unit for injection molding having an outer frame in two sections is capable of receiving inside molds with flanges. The inside molds with flanges are mounted and removed through the use of pressing mechanisms. The pressing mechanism secures the flanges of an inside mold by the use of a clamp bolt and allows for rotation so that the flange is slidable mounted in a simple manner.

Abstract: A mechanical locking mechanism for an injection mold is disclosed for holding a core rod in place in the mold cavity to resist movement caused by the injection molding pressures. The locking mechanism includes a pair of cam shafts, one carried by each of the mold halves, having a cam engagable with a concave recess in the core rod. When the mold halves are closed upon the core rod, the cams engage a portion of the recess surfaces facing toward the mold cavity. The cam shafts are subsequently rotated to move the cams to a second portion of the recess surfaces which is facing away from the mold cavity whereby the cams resist movement of the core rod away from the injection mold cavity.

Abstract: One or multiple piece golf balls are manufactured by a hot gate injection molding process in which a polymer is injected into a precise cavity defined by mating mold halves. Each individual set of mold halves is selfalignable by means of engageable inclined surfaces on the respective mold halves, which urge the halves into alignment around an axis through the poles, with one of the halves being movable around the axis to enable precise alignment around the parting line. The polymer is injected at a location spaced from the parting line to prevent the formation of a seam or irregular surface at the parting line equator of the ball.

Abstract: A device for precisely aligning, mating and clamping two injection mold plates, in which device, a first mold plate is rigidly attached to a support table and a second mold plate is slidably guided on parallel guide bars into contact with the first mold plate by at least two symmetrically placed, parallel ball spindles which are driven synchronously by a hydraulic motor.

Abstract: One aspect of the invention is a mechanism for controlling the movements of the plates in a multiple plate mold. The mold is secured to a press in an injection molding system having a support plate and top clamp plate. The mechanism includes a member pivotally mounted to the outside of the mold and an arm attaching the press support plate to the member. In a preferred embodiment, two guides are attached to the press top clamp plate and middle moving plate of a three plate mold. The guides travel in curved channels formed in the member to determine the relative positions of the plates.

Abstract: Baking tongs for producing edible wafers from wafer dough in a wafer baking oven or an automatic wafer baking machine consist of a wafer baking mold comprising baking mold parts in respective tong parts which are moved toward each other and away from each other in order to open and close the wafer baking mold. For a rigid interlocking of the two tong parts when the wafer baking mold is closed, the tong parts are provided with cooperating closure sections. The closure section of one tong part is provided with a rigid locking pin, which protrudes from the inside surface of that closure section. The closure section of the other tong part is formed with a through opening, which constitutes a passage for the locking pin, and is provided with a hook which is engageable with the locking pin. The hook is pivoted on the outside of the closure section and has an engaging surface for engaging an engaging surface of the locking pin. The hook is provided with an actuating element for pivotally moving the hook.

Abstract: A quick mold change arrangement positions and retains a mold tool in an operational mode in a mold press without the use of hydraulics. The tool is equipped with common quick change plates, and using an overhead crane is transported to the mold press and aligned in a vertical plane by rollers and guide rails. It is in its final alignment position when it rests on custom stop blocks and is retained by spring loaded clamp plates. The clamp plates are quickly seated by tightening screw-type fasteners with a tool such as an air impact wrench. The clamp plates prevent the mold tool from becoming mispositioned and damaged thereby or from creating a safety hazard. Horizontal tie bars in the mold press are also protected by the guide rails and rollers thereby preventing damage to these tie bars and resultant mold press down time.

Abstract: A high tonnage reaction injection molding (RIM) press has fixed and movable platens for clamping a composite mold therebetween at a closed mold position. A plurality of high pressure hydraulic cylinders are mounted on a carrier for the movable platen, and a locking mechanism having a plurality of incrementally spaced locking positions is effective to lock the carrier selectively at said positions. A pair of low power hydraulic piston-cylinder assemblies connected with the carrier adjacent to its opposite ends move the carrier and movable platen to the closed position. Short stroke connecting rods operated by the high pressure cylinders are forced independently of each other into high tonnage engagement with the movable platen at a plurality of locations within the area of the composite mold to clamp the latter between the platens and positively seal its junctions, whereupon a RIM mix head injects the high pressure reactive chemicals into the sealed mold.

Abstract: A mold clamping device is provided for an injection molding machine having a stationary mold half and a movable mold half supported by a movable plate. A drive rod is connected at one end to this movable plate and is received at the other end by a driving ring piston having at least one recess within its inner shell. At least one coupling member such as a split flap is swivably connected to the other end of the rod. A suitable actuator such as a piston driven lever arm is provided to operatingly engage the coupling member with the recess, whereby the mold is clamped.

Abstract: An injection molding machine and method of operation having a plurality of accessory arrangements for molding a plurality of piece parts in efficient overlapping time cycle using primary and secondary molten plastic injection units, primary and secondary clamping units, a plurality of injection units in various arrays including molding piece parts in reverse or uniform orientation.

Abstract: A stack mold apparatus for forming plastic articles is described. The apparatus includes an insulated runner system for delivering molten plastic material to the mold spaces for forming the parts. The apparatus further includes a mechanism for ejecting the solidified material of the runner when it becomes necessary to change the plastic material being used. In a first embodiment, the ejector mechanism has a pair of movable plates that form part of the central mold portion of the stack mold. In a second embodiment, the ejector mechanism has a movable plate, forming half of the central mold portion, having sucker pins and ejector bars incorporated therein.

Abstract: A clamping system includes a fixed platen fixed to one end of a machine base and a plurality of clamping cylinders, the fixed platen holding a fixed mold therein, a movable platen fixed to the other end of the machine base and holding a movable mold therein, a plurality of tie bars extending through the movable platen and including pistons at their one ends, the pistons being slidably received within the clamping cylinders, and screw threads or grooves substantially at its longitudinal center, a unit disposed between the movable platen and the fixed platen and operable to move the movable platen to and from the fixed platen, and two-part nuts mounted to the movable platen and meshingly engageable with the screw threads or grooves of the tie bars.

Abstract: A gas injection technique of injecting an inert gas (e.g., nitrogen gas) into a molten resin in a cavity, involves utilizing the strokes of reciprocation of a piston in the compression cylinder are used in a series mode, to perform a two-stage compression within the same cylinder, thereby providing a high-pressure gas. The method can also include establishing a relationship or pattern of the amount of movement of the piston with the speed of movement of the piston established to provide optimum control of the relationship between the pressure generated and piston stroke, and quantity of gas injected. The injecting gas pressure can be detected, to control a hold pressure, or the relationship between a piston stroke and generated pressure, so as to obtain optimal injecting pressure during the injection molding operation.

Abstract: An apparatus for forming objects from a moldable material such as wax. The apparatus includes upper and lower mold pieces having upper and lower mold cavity halves attached thereto. A lever arm extends from the upper mold piece and is pivotally attached to a linear actuator. The upper and lower mold pieces are pivotably connected to one another. Movement of the linear actuator results in opening and closing of the upper and lower mold cavity halves about the pivotable connection of the upper and lower mold pieces.

Abstract: An injection molding machine and method of operation including a plurality of accessory arrangements for molding a plurality of piece parts in efficient overlapping time cycle using primary and secondary molten plastic injection units, primary and secondary clamping units, a plurality of injection units in various arrays including molding piece parts in reverse or uniform orientation.

Abstract: A clamping unit has a hydraulic actuating assembly including at least two locking cylinders provided with respective locking pistons, which are connected by piston rods to a movable mold carrier. Each locking cylinder contains a high-pressure chamber and a low-pressure chamber, which are adapted to communicate with each other through overflow passages formed in the associated locking piston. The overflow passages can be shut off by valve members. The hydraulic actuating assembly has an axis of symmetry, on which a drive cylinder and a buffer cylinder are centered. The drive cylinder serves to close and open the injection mold. The buffer cylinder is connected to the movable mold carrier and has a buffer chamber, which communicates with the low-pressure chambers of the locking cylinders. The locking cylinders and the buffer cylinder have steel tubes, which are connected at both ends to common cylinder covers to constitute a unit.

Abstract: A locking device mounted in the interior portions of a mold includes a first member having an aperture therein adapted to be coupled to a first section of the mold, a second member having an aperture therein adapted to be coupled to a second section of the mold, the first and second members being alignable with one another so that the apertures therein can be aligned with each other, a pin being provided axially in one of the first and second members, the pin being radially compressible and being axially movable in the aperture in one of the members and being receivable in the aperture in the second of the members such that when the pin is axially moved into the aperture in the second section, the pin first compresses radially and then expands so as to be securely locked to the second member thereby locking the two members and the two sections of the mold together. A spring is preferably used to apply a force to keep the two sections tightly held together when in the locked condition.

Abstract: Injection molding machines for making plastic articles having a stack mold arrangement frequently suffer from the problem of unbalanced forces. Various novel techniques for counteracting and/or avoiding the production of these forces are disclosed. These techniques include the use of latches to lock an injection nozzle to a sprue bar, the use of shutters to lock the sprue bar to a stationary platen, the use of a force compensator in a moving stack mold half, and the use of an injection nozzle axially offset from the sprue bar.

Abstract: A process and apparatus for the production of bristle articles include introducing the plastic bristles in the form of individual bristles or bristle strands through channels and sleeves extending the latter in to a mould for the bristle carrier, followed by thermal melting on their end located on the mould for formation of a thickened portion and the thickened portion on the bristle ends formed during melting is then sealingly engaged on the opening of the sleeve projecting into the mould. During the filling of the mould, the bristles and sleeve are kept in position within the same and the sleeve and the thickened portion on the bristle end tightly engaging against the opening of the sleeve are enveloped by the bristle carrier material during mould filling and then the sleeve is removed from the bristle carrier.

Abstract: A mold assembly for forming solid molded chocolate shapes is formed from first and second sheet-like mold halves separably joined by permanent magnets and having base flanges that support the mold assembly in an upright position for filling through an edge fill opening. The base flanges for the mold assembly include binary-coded mold fill information utilized in chocolate shape production apparatus and specific to that particular mold assembly.

Abstract: A tie-rod assembly used in a press having an inside fixed mold end plate, an outside fixed end plate spaced from the inside plate, a movable mold plate between the end plates, and an actuator for displacing the movable mold plate toward the inside mold end plate for pressing tools carried by the mold plates together in a closing direction and for moving the tools apart in an opposite opening direction includes a tie rod extending along an axis in the direction through the movable plate and having a threaded inside end and an outside end and a stationary threaded element carried on the inside end plate and axially aligned with the tie rod displaced by the actuator independently of the movable plate between a use position and a changeover position with the threaded end withdrawn in the opening direction and spaced from the inside end plate, a nut actuated by a rotary drive for screwing the nut in the changeover position from the tie-rod on the threaded element and inside and outside bracing devices engageable b

Abstract: Described herein is an interlock system for an isostatic press machine of the type including a high pressure container having upper and lower closure plugs releasably received in upper and lower openings to be used for loading and unloading work therethrough, and a holder frame for supporting the axial force of the container in an isostatic pressing phase of the press operation, the holder frame being pivotally supported at one side thereof for swinging movements about a vertical axis into and out of a holding position in engagement with the high pressure container, wherein the interlock system is provided with a lock mechanism constantly urged to lock the holder frame in the holding position, and a control means adapted to control the lock mechanism to maintain the lock on the holder frame when the internal pressure of the high pressure container is higher than a predetermined level and to release the lock when lower than the predetermined level.

Abstract: The present invention concerns a bar for spectacles formed in two parts of relatively stiff plastic material, joined together by means of an elastic springing element in the form of a spiral spring. According to the invention, said elastic element also comprises a flat spring with surface positioned on a vertical plane, said spiral spring being wound in tight coils around a central part of said flat spring and being checked on opposite sides by two stop rings, the end parts of said flat spring forming means of anchorage into the two bar portions of plastic material.The invention also concerns a method for manufacturing said bars for spectacles, wherein said end parts of the flat spring of the elastic element are enclosed into a respective box of an injection mold, using said stop rings of the elastic element to delimit and close the mold, plastic material being then injected into said boxes to incorporate said end parts of the flat spring.

Abstract: A rotary blow molding machine includes a plurality of mold stations on a rotary carousel. Each mold station includes an elongated support body, such as multiple tie rods, with a first of the mold sections relatively movably disposed on the support body and a second of the mold sections affixed on the support body for movement therewith. An actuator is connected between the first mold section and the support body to move the support body and the second mold section. A synchronizer linkage is connected between the first mold section and the support body to effect concurrent movement of the first mold section in an opposite direction and equal amount to movement of the second mold section.

Abstract: A mold clamping system for molding articles by injecting a flowable material into a mold cavity defined by a pair of movable mold sections. The machine includes an hydraulically operated mold clamping system, and a separate hydraulic fluid reservoir for the hydraulic cylinder that provides the clamping force for holding together the mold sections during high pressure injection of molding material into the mold. The separate reservoir along with a lower, main reservoir permits a reduction of the overall height of the molding machine. The clamping system reservoir includes a level sensor, and a comparator is provided to compare the actual fluid level within the clamping system reservoir with the expected level based upon the position of the clamping ram, as sensed by a position transducer, to control the operation of an overflow valve when the actual fluid level is greater than the expected level.

Abstract: A mold clamping apparatus includes a stationary platen, a movable platen, a driving device, a rotational-linear motion transmission mechanism, a braking device, and a mold clamping force applying mechanism. The stationary platen is arranged on a frame and mounts a stationary metal mold for a molding machine. The movable platen is arranged to oppose the stationary platen to move forward/backward with respect to the stationary platen and mounts a movable metal mold. The driving device moves the movable platen forward/backward with respect to the stationary platen. The rotational-linear motion transmission mechanism is arranged between the driving device and the movable platen and converts a rotational torque of the driving device into a linear motion in a moving direction of the movable platen. The braking device is connected to the driving device and brakes a linear motion of the movable platen toward the stationary platen at the end of the linear motion.

Abstract: A clamping mechanism which includes a cylinder and a piston. The diameter of the piston is less than the internal diameter of a rear chamber of the cylinder such that fluid flows around the piston when the piston moves from an open position to an intermediate position. The diameter of the piston is equal to the internal diameter of a front chamber of the piston such that fluid cannot flow around the piston when the piston moves from the intermediate position to a closed position. To prevent cavitation within the cylinder, fluid is charged to the cylinder in accordance with the movement of the piston.

Abstract: A motor-operated die clamp mechanism produces a great clamping force even with use of small-output motors, and is adapted for use in a motor-operated injection-molding machine. Screw portion (13a, 13b), threaded reversely to each other, are formed on a ball screw (13) which is rotated by a motor (15). Ball nuts (11, 12), which are threadedly engaged with the screw portions (13a, 13b), respectively, and a movable wedge (6) are coupled to one another links (9, 10). As the motor rotates, the links contract or spread, thereby advancing or retreating the movable wedge with a great force. When the movable wedge advances, it is engagedly pressed against a fixed wedge (5) formed on the mold base (4) of a die (3), thereby causing the die to be fixedly mounted on a stationary board (1) or a movable board (2).

Abstract: Injection molding halves for forming disks having a plurality of cavities between a stationary mold unit, in which a plurality of sprue bushings and a runner with gates for introducing molten resin into said plurality of cavities are provided, and a movable mold unit in which a plurality of punches are provided concentrically to the sprue bushings for severing a central aperture of the molded disk, and an interval mechanism for providing a predetermined interval between a stationary mold unit and stationary mold base plate to ease the removal of escaped material, and connecting structure for connecting the stationary mold unit and the stationary mold base plate by alternative rotating of a connecting rod.

Abstract: During a mold thickness adjustment process of an injection molding machine, a mold touch position at which the mold halves of a mold contact each other is detected, and the mold temperature is detected by means of thermocouples attached to the mold halves, respectively. Also, the mold thickness is obtained based on the position where a movable platen and a stationary platen of the injection molding machine contact each other, which is obtained previously, and the detected mold touch position.After a molding operation is started, the mold temperature (Tn1, Tn2) is detected in each of molding cycles, and the amount of change of the mold thickness (.DELTA.e) during the period between the preceding cycle and the current cycle is calculated (S14) based on the change of mold tempreature (.DELTA.T) during the period between the two cycles, the mold thickness (e), and the thermal expansion coefficient (k). The mold touch position for the current cycle (P) is obtained (S16) based on the calculated value.

Abstract: A retainer for use in connection with injection molding that is used to retain a slide in its open position when the mold is opening. The retainer has two pivotally connected jaw members and a coiled compression spring that applies spring pressure to the jaw members as these members engage a pin that is connected to a slide when the mold is opening. The construction of the jaw members avoids undesired spreading when the pin engages the jaw members and the jaw members are constructed in a manner that enables the retainer to be easily assembled. The retainer jaw members completely surround the coil spring and protect it from dirt and only a portion of the ends of the coil spring exert a force upon the jaw members when the retainer is in use.

Abstract: The present invention relates to a wax mold holding and positioning apparatus for use with a wax injector machine where a pressure holding means uniformly clamps a two piece wax mold together and a mold positioning means is employed to move said mold to said wax injector, said apparatus including universal coupling means adapted to make any final angular shifting or adjustment to assure a firm sealing contact of a sprue hole in said mold with the wax injector to force wax through a channel in the mold to a pattern cavity therein.

Abstract: A high tonnage reaction injection molding press has a fixed and a moveable mold plate for clamping a composite mold therebetween. A plurality of high pressure hydraulic cylinders are mounted on a carrier for the movable mold plate. Fluid actuated means move the carrier and movable plate to a locking position whereat the carrier is locked adjacent to the fixed plate. Short stroke connecting rods operated by the cylinders are then forced independently of each other into high tonnage connected engagement with the movable plate at a plurality of locations within the area of the mold to clamp the mold between the plates. The high tonnage force applied independently at each location assures that the junctures of the composite mold adjacent to said locations are positively sealed.

Abstract: A method and apparatus for controlling the hydraulic pressure in an hydraulic clamping cylinder to correspond with a desired clamping force and to compensate for overshoot of the hydraulic pressure caused by time delays in operating the components in the hydraulic circuit. The control arrangement involves the sensing of the actual hydraulic pressure during the clamp force maintenance portion of a clamping cycle and comparing the actual pressure with a desired pressure to provide a correction signal to be utilized to control the operation of the hydraulic system during the next succeeding cycle so that the actual hydraulic pressure during the clamp maintenance portion of the clamping cycle during the next succeeding cycle results in a clamping force that is closer to the desired clamping force.

Abstract: A mold clamping apparatus of an injection molding machine is provided, which is capable of uniformly applying a pressing force to a movable platen. A pair of annular wedge type connection members (21, 22) are disposed within annular hollow portions (16a) of driving pulleys (16), which are respectively fitted on ball screws (14, 15) threadedly engaged with heads of upper and lower toggle sections disposed symmetrically with respect to an axis of the mold clamping apparatus. To make an adjustment for eliminating mismatch between operational phases of the toggle sections of the toggle mechanism due to flexure of the same mechanism, an urged contact state of the connection member is released by loosening bolts (23), and the ball screws, rendered to be rotatable relative to the driving pulleys, are manually rotated so that the heads are aligned with each other. After completion of the adjustment, the driving pulleys are again rendered rotatable in unison with the ball screws.

Abstract: The method having a clamping cylinder which slidably fits a clamping ram whose front end is fixed on a movable board of an injection molding machine, etc.

Abstract: A molding apparatus for producing a molding from multi-component plastic, especially polyurethane. The upper and lower parts of the mold are fastened, respectively, on mold holders of which at least one is movable relative to the other and can be propped in a closed position in which the upper mold part and lower mold part are still at a slight distance apart. Starting out from this closed position the upper and lower mold parts can be brought together and pressed against each other by a jacking device which is provided on at least one of the mold holders.

Abstract: A mold which comprises a pair of mating, openable and closeable mold halves and a lock to hold the mold halves together. The lock is defined by a recess in the outer surface of one of the mold halves. A lifting bridge crosses the recess, being proportioned to permit a lifting hook in the recess to pass underneath to engage the bridge. An elongated member is secured to the other of the mold halves, being slidably extendable into the recess when the mold halves are substantially closed. The elongated member defines a longitudinal slot facing outwardly of the recess in closed position to receive at least a portion of the lifting hook as the hook engages the bridge. The slot defines an end opposed to the other mold half which is closed, to prevent a hook portion in the slot from sliding past the opposed end. Thus, the mold in closed position cannot be opened while the lifting hook is present in the slot.

Abstract: In a die clamping apparatus including a fixed die plate, a movable die plate, a device for moving the movable die plate relative to the fixed die plate, a device for fixedly coupling the fixed die plate with the movable die plate and tie bars for carrying out clamping of dies, the tie bars are fixedly secured to the fixed die plate and a hydraulic cylinder having a ram is provided on the movable die plate, or vice versa. The coupling device has a half-nut provided on the surface of the fixed die plate so as to be movable in the axial direction of the tie bar insert hole, and are provided on the outer circumference of the tip end of the tie bar and are adapted to mesh with the half-nut. A stopper is provided between the fixed die plate and the half-nut. A part of the ram is made to butt against the stopper to position the ram in the axial direction of the tie bar insert hole. The end surface of the half-nut opposed to the ram is brought into pressing contact with the ram.

Abstract: An injection molding machine and method of operation having a plurality of accessory arrangements for molding a plurality of piece parts in efficient overlapping time cycle using primary and secondary molten plastic injection units, primary and secondary clamping units, a plurality of injection units in various arrays including molding piece parts in reverse or uniform orientation.

Abstract: A system for the rapid clamping of dies on a horizontal press for the injection moulding of plastics materials consists of a pair of structures fixed permanently along two opposite sides of the fixed and movable plates of the press and defining therewith two guides adapted slidably to receive the fixing flanges of the respective die. Motor-driven clamping means are associated with these guides and are operable simultaneously to clamp the fixing flanges of the die to the attachment structures.

Abstract: There is provided a direct mold clamping apparatus with an ejector, which is capable of uniformly applying a mold clamping force to a movable platen and is simple in construction and compact in size. A hollow cylindrical push member (12) and a movable platen (3) are coupled to each other through a single junction plane, in the form of an annular ring. A driving force transmitted through the push member is applied uniformly to the movable platen. The ejector (1) of the mold clamping apparatus (2) is provided with a ball nut (7) disposed in a hollow portion of the push member. A ball screw (6), which mates with the nut, is coaxial with a ball screw (8) for mold clamping, and has a front end fixed to an ejector pin (4) and the rear end portion removably fitted in a hole (8a) in a front end portion of the mold clamping ball screw. Thus, the axial length of the mold clamping apparatus is reduced.

Abstract: A cassette-type molding die comprises a die plate unit having fitting bores and a cassette die unit including movable and stationary cassette plates between which a molding cavity is defined, an ejector cassette plate, and ejector pins disposed between the movable cassette plate and the ejector cassette plate. The cassette die unit can be detachably inserted into the fitting bores of the die plate unit. As a result, the cassette die unit can be easily exchanged with another cassette die unit while the movable and stationary die plates of the die plate unit are very close together. This speeds up the process of changing cassette die units, and also allows for the overall cassette-type molding die to be smaller than conventional units.

Abstract: A mold clamping device is disclosed. The device includes a clamping ram, whose front end is connected to a moveable board of an injection molding machine, slidably fitted in a clamping cylinder, and a support cylinder provided in parallel to the clamping cylinder. A support piston is slidably positioned in the support cylinder, and the front end of the rod of the support piston is connected to the moveable board of the injection molding machine. A front chamber and a rear chamber of the clamping cylinder, divided by the piston section of the clamping ram, and a front chamber of the support cylinder are connected by an oil path. There is provided a valve for opening or closing the connection between the rear chamber of the clamping cylinder and the front chamber of the clamping cylinder and the front chamber of the support cylinder.

Abstract: A method of molding a plastic is initiated by injecting molten resin into a mold at a high pressure. The energy of the high pressure is partially stored in the form of elongation of tie bars of a molding machine. After the gate seals completely, the restoring force of the tie bars due to elastic deformation acts on the molded article as the mold article cools down. Each tie bar comprises a first member having a small modulus of elasticity and a second member. When the elongation of each tie bar is small, only the first member of small modulus of elasticity works. After the elongation reaches a certain amount of .DELTA.l.sub.1, the two members are connected parallel. As a result, the apparent modulus of elasticity of each tie bar increases rapidly. This makes it possible to mold a plastic with high dimensional accuracy.

Abstract: A clamping device for removably securing shaping moulds on the plates of moulding presses, wherein a catch with projecting head is secured on the mould element, while the plate of the press is equipped with a slide element which slides obliquely under the effect of a lateral jack. The slide element has an opening in the form of a button-hole cut out therein, of which the part of larger diameter is traversed by the projecting head, while the part of smaller diameter allows passage only of the cylindrical shank of the catch.

Abstract: A replaceable mold assembly for use in an injection molding machine includes first and second complemental mold halves adapted to be in a face-to-face engagement with one another; a first and a second engagement plate secured to the rear side of the first and the second mold half, respectively; and a bell crank lever pivotally secured to the first mold half and including a locking arm and an actuating arm and having a bolting position and an unbolting position. In the bolting position the locking arm engages the second mold half for interlocking the two mold halves and in the unbolting position the locking arm is out of engagement with the second mold half. A return spring is arranged in the first mold half for urging the bell crank lever into the bolting position. The actuating arm has an engagement face with a rocker profile.

Abstract: A clamp mechanism for selectively locking and unlocking a first member in a first position relative to a second member comprises a linkage system connecting the first and second members and drive means for articulating the linkage system for moving the first member relative to the second member. A fluid link is provided for locking the first member in position relative to the second member wherein the fluid link is actuated upon sensing the first member approaching the first position.