Abstract: The foregoing objects are attained by the inventive opposed gating injection method and apparatus of the instant invention for forming molded articles and for use with injection molders wherein a first mold half and a second mold half are adapted to cooperate and form at least one mold cavity. The invention includes a first injector nozzle positioned in a first mold half adjacent the cavity, for injecting a first molding resin into the cavity through a first orifice. A second injector nozzle is included which is positioned in the second mold half adjacent the cavity for injecting a second molding resin. The second resin may be different from the first resin or the same as the first resin. The second resin is injected through a second orifice unconnected with the first orifice. In accordance with the invention, the injector nozzles may be either simultaneously or sequentially activated for filling the mold cavity, and may be single material or co-injection type nozzles.

Abstract: A greaseless mold carrier and alignment system includes a tie rod bracket on each of a pair of lower tie rods of an injection molding machine. Each tie rod bracket has a top bearing plate and a side bearing plate. A center mold section of a stack mold assembly has mold brackets connected to opposite sides thereof, each mold bracket having sets of bearing rollers rotatably supported thereon to engage respective bearing plates. The system provides moving vertical support and lateral alignment to the center mold section for precise engagement with stationary and movable mold sections of the stack mold assembly of the molding machine.

Abstract: The equipment is for the moulding of plastics containers made of two different materials, particularly for the production of parisons for PET bottles comprising an inner portion of virgin PET and an outer portion of recycled PET. The equipment comprises a die plate having rotatable supports each carrying a pair of cores or male elements which are thus associated alternately with matrices of two different types so as to produce the inner portions and the outer portions of the parisons in two successive moulding steps.

Abstract: An injection molding process for the manufacture of composite, molded, thermoplastic articles comprising an insert member contiguous with a second body of molded thermoplastic material, is carried out in a mold assembly comprising a core member and a cavity member engageable therewith. The core and cavity members cooperate to define a first molding station having a first cavity for molding an insert member, and a second molding station which is configured to receive and support an insert member therein, and to provide a second molding cavity contiguous with the insert member for molding a thermoplastic body contiguous with the insert. At the start of the process, an insert is supported in the second station, and thermoplastic materials are injected into the molding cavities in the first and second stations so as to mold an insert and a completed, composite member.

Abstract: A mold device for resin-packaging semiconductor devices is provided which includes a first cavity block having a first molding cavity, a second cavity block having a second molding cavity in corresponding relation to the first molding cavity, and a gate for injecting a resin material into the first and second cavities through a runner. The gate is defined between an opposed pair of first and second gate pins at a corresponding corner portion of each molding cavity. The first gate pin is removably insertable into the first cavity block, whereas the second gate pin is removably insertable into the second cavity block. Further, the gate is directly open to both of the first and second molding cavities.

Abstract: A molding die has a plurality of cavity groups each occupying four corners of a rectangular area for accommodating semiconductor chips mounted on a lead-frame, pots each occupying a central area of the rectangular area and a plurality of runner groups each having straight runners equal in length and connecting the pot to the cavities in the four corners, and molten resin concurrently reaches the cavities in the four corners so as to produce semiconductor devices without non-filling or partially filling cavity.

Abstract: An injection-molding apparatus has a housing, a plate fixed on the housing, a plurality of fixed mold halves on the fixed plate, a plate movable along an axis toward and away from the fixed plate and supported on the housing without tie rods, respective movable mold halves on the movable plate engageable with the fixed mold halves, and an actuator rod passing axially through the fixed plate between the fixed mold halves and having an outer end fixed to the movable plate and an opposite inner end. An actuator fixed to the housing and to the inner rod end displaces the movable mold plate and the movable mold halves axially toward and away from the fixed mold plate and fixed mold halves.

Abstract: Multi-cavity injection molding apparatus having two heated manifolds interconnected by a connector bushing all extending in a common plane. A threaded portion of the connector bushing is screwed into a threaded opening in one manifold and a nonthreaded portion of the connector bushing is received in a nonthreaded opening in the other manifold. The nonthreaded portion of the connector bushing fits in the nonthreaded hole in the other manifold tightly enough to prevent melt leakage, but is still able to slide sufficiently in the opening to accommodate thermal expansion and contraction of the heated nozzles relative to the cooled mold in which they are mounted and located. In one embodiment, the connector bushing is made of a material such as a beryllium copper alloy having a greater coefficient of expansion than the steel manifolds so it can be easily installed and then expand to produce this fit when heated to the operating temperature.

Abstract: Injection molding apparatus with a central heated manifold, a pair of connector manifolds, and at least four nozzle manifolds mounted to extend in a common plane in a mold. A number of heated nozzles extend from each nozzle manifold. A melt passage branches in each nozzle manifold and the nozzle manifolds are made so thermal expansion slides the branches of the melt passage into exact alignment with central melt bores through the nozzles. The central manifold and the two connector manifolds extend along a central axis and each connector manifold is between each pair of nozzle manifolds which are offset from the central axis. Connector bushings slidably connect each connector manifold rearwardly to the central manifold and sidewardly to each nozzle manifold.

Abstract: An injection molding machine having a plurality of axially arranged mold stations including structure for supporting sets of mold plates and a mechanism for opening, closing and overstroking mold plates.

Abstract: In an injection molding apparatus in which first and second mold parts are combined to define therebetween an insulated section of a runner system through which molten plastic material is injected into at least one mold cavity, spring-biased plungers are included in at least one of the first and second mold parts for restraining a shell of plastic material within at least a part of the insulated section of the runner system from contacting any portion of at least one of the mold parts within the insulated section of the runner system other than the plungers when the first and second mold parts are separated from one another.

Abstract: Multi-cavity injection molding apparatus having four nozzle manifolds mounted in a common plane with a central inlet manifold having two arms extending in opposite directions. The central manifold has a longitudinal axis extending in a first direction through the two arms. Each nozzle manifold is offset from the central manifold in a second direction that is substantially perpendicular to the longitudinal axis. Each nozzle manifold has a locating pin to locate it in a second direction perpendicular to the first direction. The locating pin allows thermal expansion to slide the nozzle manifold in the first direction into a position wherein each branch of the melt passage is aligned with the melt bore through one of the nozzles extending from the nozzle manifold. A pair of the nozzle manifolds are connected on opposite sides of each arm of the central manifold by connector bushings.

Abstract: An apparatus for molding polystyrene mold halves which are used, for subsequent molding of a soft contact lens. The apparatus is designed with superior heat conduction capacity so as to minimize the molding cycle time, while simultaneously producing uniformly precise and accurate optical quality surfaces. Molten polystyrene is provided via a hot runner system to a plurality of mold cavities. In a specific variation, the convex surface provides the optical quality surface to the concave surface of the mold half produced thereby. The structural element which defines the convex surface includes a hollow cylindrical bushing and a removable power insert mounted therein, which may be changed so that the prescription strength of the contact lens to be formed by the mold may be varied. In a first embodiment, the power insert includes only a convex surface at its operational end.

Abstract: The invention relates to a two-stage injection-molding machine with a fixed mold plate, a movable mold plate and a two-part intermediate assembly, arranged to be movable between said plates, and with a supply of injection-molding material for the intermediate assembly to supply the stages formed between the intermediate assembly and the mold plates with injection-molding material. In order to simplify the production of injection-molded parts of different colors in one and the same injection-molding process it is proposed, in accordance with the invention, that for each stage there has been provided a separate supply of injection-molding material via a separate main channel. In addition to the free choice of the color for each stage, it is possible to use various types of plastic per stage in one and the same injection-molding process.

Abstract: An injection molding apparatus includes a nozzle which is directly connected to a mold for injecting a molding material into the mold. The mold defines at least one cavity in the shape of a element to be molded and at least one gate passage, each gate passage interconnecting a separate cavity with the nozzle. The shape of the gate passage permits a rapid curing of any residual molding material, and permits separation of the mold and the nozzle before the molding material in each cavity is cured. The nozzle is then used for a subsequent procedure or molding process while the molding material in the cavity cures. The nozzle defines a first bore and a second bore arranged longitudinally in sequence, and a side hole for introducing the molding material into the first bore. The nozzle includes a first plunger which is selectively reciprocally movable in the first bore, and a second plunger which is selectively reciprocally movable in the second bore and in a central bore defined in the first plunger.

Abstract: In a multi-cavity molding apparatus that includes a cavity part having a plurality of cavity sections that is combined with a core part having a plurality of cores to define a plurality of mold cavities therebetween, and a plurality of locking rings respectively disposed around a plurality of the cores for engagement with respective cavity sections when the core part is combined with the cavity part, a cavity shield is attached to the cavity part to prevent molded products ejected from the mold cavities from entering spaces between the cavity sections of the cavity part and a core shield is attached to the core part to help prevent the ejected products from entering spaces between the cores of the core part. The cavity shield and the core shield thereby respectively limit obstruction by the cavity part and the core part of removal of the ejected products from the space between the cavity past and the core part. The core shield includes more than the ejection means.

Abstract: A redistributing device for use with melt flow exhibiting boundary layer flow and centralized flow comprises a body including a melt flow inlet end and a plurality of melt flow outlets. A first flow diverter is included for distributing at least the boundary layer flow among the plurality of the melt flow outlets. A second flow diverter is included for distributing at least the centralized flow among the plurality of melt flow outlets.

Abstract: A biofilter load comprises a stack of blocks of a fired porous clay material having passages extending vertically therethrough for flow of sewage. The passages may be molded in the blocks or may be formed between adjacent blocks by the method of stacking. The blocks are stacked in a frame which is placed in the biofilter. The blocks are manufactured from 8-12 mm clay granules placed in a mold in a layer of 60-80 mm. The clay is heated to the temperature at which the granules begin to swell, is maintained at a temperature in the range of swelling of the clay for a set period of time, and cooled in multiple stages. The process produces blocks with deep branched open pores to provide optimum conditions for development of microorganisms on the pore surfaces and bacteria-denitrification in the deep pores to improve the efficiency and productivity of sewage treatment.

Abstract: Throttle butterfly, especially a throttle butterfly in an intake channel of an internal-combustion engine which has a throttle butterfly shaft extending concentrically to a central axis. The throttle butterfly as well as the housing surrounding it have sealing surfaces facing one another.

Abstract: A method and apparatus for injection molding several different parts in a reconfigurable mold is disclosed. The mold machine (10) includes a first mold body (14) attached to a machine frame (12) and second and third mold bodies (16, 18) that are movable with respect to the first mold body (14). A mold frame controller (100) is interconnected to and controls three linear actuators (56, 66, 88) that are arranged to move the three mold bodies into different configurations. Each mold body has mold cavities (24, 44, 46, 80) that can be aligned with mold cavities in the other mold bodies to form different combinations for forming a variety of different parts.

Abstract: An apparatus is provided for molding lead frames. The apparatus has a mold formed by two mold halves. An assembly for introducing a lead frame into one of the mold halves, an assembly for carrying encapsulating material into the cavities of the mold and an assembly for removing an encapsulated product from the mold are arranged on a carriage movable along a guide relative to the mold halves.

Abstract: A gate portion constituting a gate of a resin molding die is made of a hard alloy having a hardness greater than the predetermined hardness in the iron-based hard alloy used to form a cavity block and a center block. Opposing surfaces of the cavity block halves include a polytetrafluoroethylene layer at least at the portions thereof which contact portions of the lead frame in a semiconductor encapsulation molding apparatus.

Abstract: A resin encapsulating molding die for manufacturing a semiconductor device includes a cavity piece having a cavity on which a lead frame with a mounted semiconductor element may be placed, with the semiconductor element in the cavity, and a gate piece having a gate portion including a sub-runner through which a molten resin for encapsulating the semiconductor element is introduced into the cavity, the gate piece being detachable from the cavity piece. The molding die also includes a sealing dam disposed adjacent the sub-runner for blocking flow of molten resin from the sub-runner toward leads of the lead frame. The sealing dam may be a clamp structure for clamping the leads closest to the gate portion, the sealing dam and cavity piece may be a continuous unitary structure, and the sealing dam may have a parting surface substantially coplanar with a parting surface of the cavity piece.

Abstract: Hot tip injection molding apparatus having a heated melt distribution manifold for conveying melt to a number of gates. A number of nozzle manifolds are closely mounted to the front surface of the heated manifold. Each nozzle manifold has a number of spaced nozzle portions extending from a rear manifold portion. A melt channel branches from an inlet on the rear surface of the rear manifold portion to an outlet on the conical surface of each nozzle portion. The rear surfaces of the nozzle manifolds are rectangular rather than round to improve the efficiency of heat transfer from the heated manifold to the nozzle manifolds.

Abstract: A molding die for sealing a semiconductor element with a resin includes an upper and a lower mold half. A leadframe having a resin passage aperture is sandwiched between the lower mold half and the upper mold half. The lower mold half has a lower runner space, a lower cavity, and a lower gate provided between the lower runner space and the lower cavity. The upper mold half has an upper resin well, an upper cavity, and an upper gate provided between the resin well and the upper cavity. The length of the upper resin well in the direction of the flow of resin is equal to or greater than the distance from the lower gate to the front edge of a lower runner rising slope, to thereby obtain a final product which is free from resin burrs formed in the upper resin well.

Abstract: The invention is to a transfer mold design utilized with conventional transfer encapsulation. The design utilizes a varying runner cross section with an intermediate varying depth well or reservoir from which a constant gate depth and gate entry angled to the mold cavities is employed. The method and apparatus of the invention is applicable to single and multiplunger molding utilizing thermoset and thermoplastic encapsulants for semiconductors.

Abstract: For injection molding of tooth brushes from two different molding material components with tufts of bristles incorporated in the head portions of the brush bodies a molding machine is proposed which includes a tuft loading station, a first injecting station associated with the first material component and a second injecting station associated with the second material component. In one or each injecting station, the stationary molding block has a recess, and a movable mold insert part fits into this recess to complete the stationary mold block. The movable mold insert part is provided with tuft insertion holes and can be transferred to the tuft feeding station where tufts of bristles are loaded into the tuft insertion holes so that they have their inner ends projecting into the mold cavity portion defined by the movable mold insert part. Production of tooth brushes is a continuous sequence of tuft loading and injecting steps.

Abstract: An injection molding machine having a plurality of axially arranged mold stations including structure for supporting sets of mold plates and a mechanism for opening, closing and overstroking mold plates.

Abstract: An apparatus forms multiple resin layered parisons that are cooled or blown into bottles. The individual resin layers are injection molded in sequence and the formed parisons are transferred to each cooling and molding station by an axially and laterally indexing platen.

Abstract: A molding machine has a mold material supply device, a die setting device, a separating device and a deburring device. The supply device includes a mold material feeding device, an extruding device for receiving a mold material from the mold material feeding device and extruding the mold material so as to form an extruded mold material, a cutting device for cutting the extruded mold material, and a transfer device for receiving the extruded mold material from the cutting device and transferring the same.

Abstract: An arrangement for molding a front or back polystyrene mold half which is used, with a second complementary back or front mold half, for subsequent molding of a soft contact lens such as a hydrogel soft contact lens. Each mold half defines a convex curved surface and a concave curved surface spaced therefrom, with one of the surfaces defining an optical quality curved surface for the soft contact lens. A heated molding machine introduces molten polystyrene through a hot runner system to a plurality of mold cavities, each of which defines an optical quality curved surface and also a second noncritical surface. The optical quality surface of the mold cavity is positioned further away from the heated hot runner side of the mold than the second surface, which allows faster cooling of the optical quality surface of the mold cavity. Each mold cavity has a first insert on the optical quality side of the mold cavity and a second insert on the second side.

Abstract: A pressure molding apparatus for molten resin in which an oil-pressurized cylinder internally holding an end of gate pin can freely move in compatibility with thermal elongation or contraction of a manifold pipe. In addition, a limit switch to be activated by the descending movement of this cylinder in correspondence with the descending movement of the gate pin is interlinked to a molten-resin supply source. By provision of these mechanisms, molten resin can smoothly be delivered to the interior of a molding unit without obstruction. Since substantial space is provided around this cylinder, pipes can easily be installed. Furthermore the inner later surface of the gate aperture on the side of the gate pin is provided with an obtuse angle wider than the tip angle of the gate pin, and a tapered hole having an adequate length and tapered diameter expanding itself from the gate aperture to the inner surface of the molding unit is provided.

Abstract: A case houses a portable telephone apparatus having a display portion, an operating portion, a speaker portion and a microphone portion provided with respect to two main portions and a hinge portion which connects the main portions so as to be opened and closed. The case is formed of plastic molding. The hinge portion is formed of a soft resin having a resiliency, and the main portion is formed of a hard resin and integral with the hinge portion. A wiring member for provide an electric connection between the main portions extend through the hinge portion.

Abstract: A device for molding a buffer cap at the same time of fixing the cap to the bristle base implanting head of a toothbrush body preform. In the buffer cap molding and fixing device, a stationary molding plate is coupled to a mounting plate by a stop rod such that it is limited in its moving distance. The stationary molding plate has a plurality of sprues aligning with a plurality of gate holes. The bottom surface of the stationary molding plate has a plurality of top cavities, communicating with the sprues through their respective gates and each having a wider section provided with a pair of holding projections for holding a toothbrush body preform. The gates are formed at necks of the top cavities respectively. A back up plate is interposed between the stationary mounting plate and the stationary molding plate. A core plate comes into contact with the stationary molding plate at a parting plane. The top surface of the core plate has a plurality of bottom cavities corresponding to the top cavities.

Abstract: The monolith includes a base of plastic resin material having elongated bristles of the same resin material monolithically relatively upstanding on one side thereof so that the monolith can be used as a brush. The base of the monolith is molded in a cavity having branches thereof in which the bristles are formed. The bristles are formed to have shank portions relatively upstanding from the one side of the base to points on the longitudinal axes of the bristles relatively intermediate between the one side of the base and the tips of the bristles, and tip portions extending relatively outwardly along the axes of the bristles from the intermediate points to the tips of the bristles.

Abstract: The present invention relates to a molding apparatus having a first mold half with a core portion and a second mold half with a cavity portion wherein the core portion moves relative to the cavity portion between mold open and mold closed positions. The molding apparatus further includes a carrier plate for receiving molded articles and holding inserts to be incorporated into the molded article. The present invention also relates to transferring the inserts to the mold cores prior to molding.

Abstract: A nozzle for directing molding material from a material source to a sprue, includes a first surface adapted to connect the nozzle to the material source. The first surface is also adapted to be adjacent to and pivotally movable relative to the material source and in material communication with the material source. A second surface is adapted to be positioned adjacent to and pivotally movable relative to the sprue. The second surface is in material flow communication with the first surface and adapted to be in material flow communication with the sprue. A channel is included for establishing the material flow communication through the nozzle.

Abstract: A plunger (22), used in a standard mold, has a movable piston (23) and spring (24) that reduce the cull space when piston (23) is pressed downward into the cull mold compound.

Abstract: An apparatus is provided for making molded photointerrupters by using first and second leadframes. The first leadframe carries a plurality of light emitting devices, whereas the second leadframe carries a plurality of light receiving devices. The apparatus includes a molding unit which includes: a lower mold member which supports the first leadframe in a horizontal posture; an upper mold member movable vertically toward and away from the lower mold member; and a pair of side mold members movable laterally toward and away from each other between the upper and lower mold members, one of the respective side mold members supporting the second leadframe in a horizontal posture; wherein the respective mold members forms molding cavities when the mold is closed.

Abstract: An apparatus and method for connected forming and controlled stacking of material having a form (12). The form (12) includes at least two molds (14) connected to each other by a web (16). The introduction of material into the form (12) results in the material generally assuming the shape of the molds (14) and the web (16). As a result, when the material is pressed out of the molds (14), the material is held together in the preselected position by the resultant web (16). This enables the stacking of material on top of each other in a controlled and certain manner since the forms pressed from the molds (14) will retain their chosen spaced apart distance and fall consistently and uniformally on top of each other until such time as the desired height of stacked material is achieved.

Abstract: A mold and injection molding process for the production of a fishing lure having multiple, integral bristles extending vertically from the lure. The mold defines an internal cavity in communication with an injection port and a ventilation port. The internal cavity defines a fishing lure having a desired shape. The cavity contains a pair of porous halves that facilitate the formation of integral bristles. Molten material is injected into the cavity through the injection port while air escapes through the ventilation port. The molten material penetrates the porous insert to form the bristles. The bristles are concurrently and integrally molded with the rest of the lure. After curing, the fishing lure is removed from the mold.

Abstract: Encapsulation molding equipment includes individual loading bars each having an elongated support surface which receives strip-like carriers supporting semi-conductor chips and like objects for encapsulation. Cavity inserts having plural rows of cavities of different size and dimension individual to carriers having like numbers of chips of a range of size and dimension fit over the strips with each cavity on an insert surrounding the chip to be encapsulated. Converging gate passages and vent passages are formed on the surface of the insert spaced away from the mold base member for supply of resin from a central resin receptacle to the cavities. Support of the cavity inserts independent of the loading bars and resilient mounting of the loading bars is disclosed. The mold is completed by an upper mold member which closes the mold and effects a seal between the mold parts and provides for delivery of encapsulating resin to the cavities in the cavity inserts.

Abstract: A method and apparatus for molding casing halves of a magnetic tape cassette in which one or more-windows in the casing half are firmly retained by remaining portions thereof regardless of the solubility of the two plastic materials employed or other molding conditions. The window is formed with a projecting edge portion which extends well into the plastic of the remaining portions of the casing half. In one embodiment, the window is molded first and then the remaining portions are molded around the edge portions of the window. In another embodiment, the other portions are molded first using slidable cores to define the window portions, and then the windows are molded.

Abstract: An injection mold for use with a molding press has four mold levels in axially stacked relation, permitting a substantial doubling of output for a given size of press as compared with a back-to-back two level stacked mold. The mold feeder flow path extends axially from the injector head to a flow distribution block located at the centre of the stacked mold block series. The centrally located distribution block is connected, in sealed relation with the injector head, being axially displaceable therefrom in continuing sealed relation upon the opening of the mold. A drool prevention valve system, located at two of the mold interfaces, to preclude drooling of fluid plastic stock upon opening of the molds includes pressure fluid actuators for operating the valves, wherein the pressure fluid may comprise the fluid plastic stock.

Abstract: A manufacturing method forms flanges for use in a film cartridge which are made of resin. Each flange is made of the resin by an injection molding process. Gates to cavities provided in a mold are located such that residual portions of solidified resin at the gates, remaining after the injection molding process has been completed, do not come into contact with a film in the cartridge as the film is moved into and out of the cartridge.

Abstract: A process for producing a container is disclosed including molding the container using an injection molding machine with a multicavity mold having not less than 12 cavities by charging a hot runner thermoplastic resin having a melt flow rate of 5 to 80 g/10 minutes to the multicavity mold, wherein not less than 70% of the total injected resin amount at each shot is injected at an injection speed which is adjusted at 150 to 270 mm/sec., and the remaining resin at each shot is injected at a final injection speed which is adjusted at 3 to 90 mm/sec. By employing the process, molding troubles such as burrs, stringiness, short shot and weld lines do not occur, and the container can be molded continuously for a long period under unmanned conditions without screening inspection.

Abstract: A multi-level stacked mold having at least two and as many as four levels of cavities has a stock distribution mold block centred axially of the stacked mold blocks, the axially extending stock inlet passage to the distribution block connecting with radially off-set stock transfer passages that cross the axially openable mold block interfaces, into the adjoining mold blocks. These openable stock transfer passages, are each provided at their respective, non-encapsulated, radially off-set, opening interfaces with a valveless anti-drool arrangement. The mold flow passage system is subject to continual, extreme, thermal cycling and cyclical mechanical loading, during the repeated opening-and-closing cycles of the mold. Each separable anti-drool sealing interface has a relatively axially displaceable portion extending to bridge the initial gap opening between adjacent mold blocks and serving as an expansible piston means.

Abstract: A case for housing an electronic apparatus has two main portions and a hinge portion which connects the main portions so as to be opened and closed. The case is formed of plastic molding. The hinge portion is formed of a soft resin having a resiliency, and the main portion is formed of a hard resin and integral with the hinge portion. A wiring member for provide an electric connection between the main portions extend through the hinge portion. The wiring member passes at a center of rotation on which the hinge portion is turned.

Abstract: Encapsulation molding equipment includes individual mold bases each having an elongated shallow recess which receives strip-like carriers supporting semi-conductor chips and like objects for encapsulation. Cavity inserts having various numbers of cavities of different size and dimension individual to carriers having like numbers of chips of a range of size and dimension fit over the strips with each cavity on an insert surrounding the chip to be encapsulated. Gate and vent passages are formed on the surface of the insert spaced away from the mold base member for supply of resin from a central resin receptacle. Gate passages in the cavity inserts are configured to provide a restriction at the edge of each mold cavity, thereby accelerating the flow of liquid resin, rapidly filling the cavities and avoiding the entrapment of gas bubbles. The inserts have mold vent passages which allow for rapid venting of displaced gases from the cavities.

Abstract: A gas spring (602) is used as a buffer device in a resin-sealing apparatus for applying a compressive force to a plunger (15). In the gas spring (602), the compressive force at which a compression displacement starts is easily established as required, and the increasing degree of the compressive force with increasing compression displacement is established slowly without difficulty. Any errors in applying resin injection pressures to a plurality of plungers, due to variations in the amount of resin of tablets and in length of plungers, are absorbed in a wide range of the compression displacements thereof so that the resin injection pressures in practice are substantially equalized.