Abstract: A process for producing a seat element from a portion of an outfit (1) including a relatively compact plastic covering layer, a network formed by a continuous sheet of metal springs (5), the intermingled turns of which, on one side, come substantially flush against the lower face of the covering (1), and an intermediate connecting layer (3) made of a plastic foam which partially encases the turns of the sheet of springs (5).According to the invention, the peripheral edge (7) of the said outfit portion is gripped in an injection mold (11), this mold having a cavity (9) into which the said edge (7) penetrates, a thermoplastic to which an expanding agent has been added is injected into the said cavity at low pressure, and this thermoplastic is allowed to harden there.

Abstract: A device for at least partially encapsulating a border of a substantially sheet shaped element, and including a mould having at least two parts for pressing therebetween the element. The mould has a shape such that, when the element is pressed between the parts of the mould, a cavity is formed around the border. The device has an injection opening for injecting a moulding substance into the cavity. The cavity is formed by an elastically deformable member having a profile which extends along an encapsulation borderline of the element and which is adapted to be elastically deformed while maintaining a tight contact along the encapsulation borderline when pressure is applied thereon in order to follow irregularities in the element along the borderline. Also, a method for at least partially encapsulating a border of a substantially sheet shaped element.

Abstract: A method of forming a bilayer glazing panel by providing an optically clear prelaminate of stretched polyester film coated with a cross-linked, self-healing polyurethane layer; assembling the prelaminate with a layer of plasticized partial polyvinyl butyral with the side of the polyester film without the polyurethane layer in facing contact with a subjacent textured surface of the partial polyvinyl butyral layer; clamping the assembled layers in a perimeter anchoring system; sequentially carrying out the following steps i), ii), iii), and optionally the above clamping step within an air autoclave; i) deairing the interface between the polyester film and plasticized partial polyvinyl butyral; ii) forcing localized regions of the layers within the perimeter anchoring system against a sheet of glass; and iii) subjecting the assembly of step ii) to elevated temperature and pressure while the plastic layers remain clamped within the perimeter anchoring system to firmly bond the plastic layers and glass sheet toget

Abstract: A process for manufacturing zip fasteners by molding sets of locking members of any length and of the staggered or slit type, the upper stop members, the coupling and the box, in a single operation. The process is achieved with a two-part injection molding tool having strips with recesses for forming locking members which are applied to both the lower and the upper part of the tool. The lower strips can be moved vertically. A transverse slide has recesses for the upper stop members, a recess for the coupling, and a mold part for a box, in which is located a mold body displaceable within the plane of the slide. In order to form locking members with slits the lower part of the tool is provided with a mechanism which removes the insert forming the slit from the slit when the finished zip fastener member is removed. Accordingly, all combinations of zip fasteners can be manufactured in a single operation without expensive subsequent processing.

Abstract: A device and method for manufacturing a layered article having a beveled edge and including a flexible outer layer and an internal elastomeric layer. The device comprises independently operative bearing surfaces wherein a first surface exerts a first pressure on the article body and a second surface exerts a second pressure on the article edge.

Abstract: A method of manufacturing a sealing gasket on the rim of a sheet of glass has a preformed sealing gasket fixed to the rim of a glass. Polymerization is carried on in situ with a polyurethane material in a modified mold in which the preformed sealing gasket is positioned. The preformed sealing gasket also forms a sealing junction to avoid leakage of the polymer material.

Abstract: Producing an encapsulated glazing unit having a weather-stable film on an exposed surface of the gasket. There is provided a two-part mold whose sections cooperate to define a mold cavity for receiving the peripheral margins of the transparent glazing unit upon which the gasket is to be formed. A sheet of the weather-stable film is positioned over the mold section having the portion of the cavity which defines the surface to which the film is to be applied. With the mold closed, a flowable gasket forming material is injected into the mold cavity behind the film to deform the film into conformity with the mold surface. As the gasket cures in situ, the film fuses to its surface. The encapsulated unit is removed from the mold and the excess film is trimmed from around the gasket.

Abstract: A method of preparing window glass provided with a gasket at a peripheral portion of a glass sheet for a window includes placing a glass sheet in a shaping mold which has two mold parts to provide an inner cavity in which resilient sealing members are attached respectively to the two mold parts so as to come in contact with surfaces of the glass sheet so that a gasket forming cavity is formed at a peripheral area of the glass sheet by the cooperation of the inner cavity of the shaping mold, the resilient sealing members and the glass sheet. The resilient sealing member is then pushed to the contacting surface constituted by the resilient sealing member and a part of the shaping mold in the inner cavity via a pushing means after the assembling of the shaping mold and the glass sheet. A gasket material is then injected into the gasket forming cavity to form a gasket.

Abstract: An insulating architectual glass unit for residential, nonresidential and commercial applications having at least two panes of glass plate separated by an encapsulated air space is constructed with an injection molded frame of relatively low thermal conductivity material wherein a secondary seal between the individual glass plates and a frame structure surrounding the glass plates are molded as a single piece continuous structure in a single step operation.

Abstract: A felted paper loudspeaker diaphragm in which the felted paper of the annular supporting flange is thinner, and of lesser density and higher compliance then the cone body. The supporting flange is permeated with a high compliance elastomer which provides most of the tensile strength of the supporting flange.

Abstract: A pleated paper filter element is disclosed which is formed from a mechanically-treated filter paper (10') which has the side thereof opposite to the wire-side (12) mechanically teased so as to form thereon an open, textured layer (18) of raised fibers. The starting material used is a standard, commercially-available filter paper which is resin-impregnated with an uncured phenolic resin. The pleated paper filter element formed from the treated filter paper (10') displays, after the element has been heated to cure the resin, a substantial increase of up to 73.5% in the dust-holding capacity over a like element formed from the standard, commercially-available filter paper.

Abstract: A photovoltaic panel is supported, sealed and isolated from the environment by being encased in a reaction injection molded elastomer which encapsulates the back, sides and a portion of the front side of the photovoltaic panel.

Abstract: A process for making a glazing product which includes forming a gasket on a sheet of bilayer glass with a self healing transparent elastic plastic layer bonded to one side of the glass. A removable protective material is applied to the plastic layer. The assembly is placed in a mold cavity and a plastic material is injected into the mold cavity to form a gasket. The protective material is removed from the plastic layer after the gasket has formed.

Abstract: The process makes it possible to manufacture any zip fasteners, i.e. to mold sets of locking members of any length, of the staggered or slit type, the upper stop members, the coupling and the box in a single operation. The apparatus for injection moulding all these components comprises a two part injection moulding tool wherein strips with recesses for the forming of locking members are applied to both the lower and the upper part of the tool and the lower strips can be moved vertically. The transverse slide has in addition to recesses for the upper stop members and the recess for the coupling a mold part for the box, in which is located a mold body which can be displaced within the plane of the slide. In order to form locking members with slits the lower part of the tool is provided with a device to remove the insert which forms the slit from the slit when the finished zip fastener member is removed.

Abstract: An encapsulated multiple glazed structure is formed by positioning at least two spaced apart substantially coextensive sheets of glazing material wherein the sheets are maintained in aligned spaced relation by a suitable spacer element adjacent the peripheral portions of the facing surfaces of the glazing sheets. The above assemblage is then typically placed within a mold cavity of a suitable molding apparatus and a charge of an elastomeric gasket forming material is injected therein to form an encapsulating gasket around the peripheral edge portions of the assemblage to produce a multiple glazed structure.

Abstract: A unique dynamic seal assembly is used in a mold structure for encapsulating a glass window assembly with a gasket. The seal assembly resiliently supports the window assembly and cooperates with the mold structure for defining a gasket forming cavity. The mold structure typically includes two cooperating mold sections, each of which can be provided with a groove for receiving a separate dynamic seal assembly. Each seal assembly includes a first sealing body having a sealing surface which faces and is adapted to sealingly contact the window assembly. The first seal element is formed of a non-deformable, non-compressible material and is connected to a second seal element formed of a deformable, non-compressible material which is responsive to pressure applied to the first seal element for adjusting the position of the first seal element in the mold to accommodate thickness variations in a window assembly contacting the first surface.

Abstract: A method of applying end stop members by injection molding to a slide fastener having rows of coupling elements on opposed stringer tape edges, a predetermined length of each of these tape edges being held upright or substantially vertical to the plane of the tape web and embraced by end stops molded in place with that predetermined length of tape edges maintaining alignment with its neighboring contiguous tape edge outside the molded end stop.

Abstract: A window assembly includes a transparent glass sheet and gaskets formed by curing a polymeric gasket material in situ on the glass sheet to encapsulate a marginal peripheral edge portion thereof. A glass sheet to be utilized in a vehicle door has a front edge, rear edge and a lower edge to each of which is adhered such a gasket. In addition, a bracket means for attachment to a scissor linkage for raising and lowering the window can be secured to the lower edge of the window. The gaskets are formed in a mold with the transparent sheet and bracket means, typically by a reaction injection molding process. Each of the front and rear gaskets may have a flange portion thereon for insertion in an opening in a gasket attached to a frame of the window opening in the vehicle door.

Abstract: An insert which forms the show or finish surface (the surface exposed to the weather) for an elastomeric gasket in an encapsulated window assembly is thermoformed from a sheet of plastic and placed in the lower half of a mold. A sheet of glazing material is also placed in the lower mold half and an upper mold half is utilized to close the mold cavity. Gasket forming material is injected into the mold cavity to form a gasket in situ which adheres to both the peripheral marginal areas of the transparent sheet and the insert. The insert can be formed with a gate portion which extends into the gate area of the mold and prevents the gasket forming material from flowing onto the surface of the insert which is to be exposed in the final glazing. In one embodiment, the insert can be formed in its final configuration with a central opening leaving the transparent sheet exposed. In an alternate embodiment, the insert is formed with a centrally disposed portion which covers the transparent sheet material to protect it.

Abstract: A molded fiberglass product and process for producing that product are disclosed. A fiberglass mat is molded to a desired shape. It is trimmed and placed between two sheets of facing fabric, the facing fabric pretreated with a thermoset binder and a heat activated adhesive. The facing sheets and fiberglass mat are placed into a press with a heated mold where the fiberglass is compressed at its edges and the sheets are sealed to the fiberglass and beyond the fiberglass edges to each other. The resultant workpiece is trimmed and the final product is a completely enveloped molded fiberglass product with all fiberglass surfaces and edges, both external and internal, enveloped in facing, no fiberglass exposed.

Abstract: A method of forming a window assembly which includes a windshield and a gasket formed by curing a polymeric gasket material in situ on the windshield to encapsulate a marginal peripheral edge thereof and form an integral leaf screen and mounting tab. The gasket is formed in a mold with the windshield typically by a reaction injection molding process. The gasket-forming cavities in the mold can be separated by removable plugs and be connected to multiple inlet means for separately filling the cavities. The gasket, leaf screen and mounting tab can be formed of one material, or the leaf screen and tab can be formed of a different material then the gasket.

Abstract: A window assembly includes a windshield and a gasket formed by curing a polymeric gasket material in situ on the windshield to encapsulate a marginal peripheral edge thereof and form an integral leaf screen and mounting tab. The gasket is formed in a mold with the windshield typically by a reaction injection molding process. The gasket-forming cavities in the mold can be separated by removable plugs and be connected to multiple inlet means for separately filling the cavities. The gasket, leaf screen and mounting tab can be formed of one material, or the leaf screen and tab can be formed of a different material than the gasket.

Abstract: An improved window gasket assembly and the apparatus and associated method for reaction injection molding such as assemblies, as well as other molded articles, are disclosed. The gasket is preferably integrally molded from an elastomeric material such as urethane onto a substantially transparent window panel. The gasket and window assembly can then be mounted and secured directly to vehicle body panel opening, for example, with adhesives, thereby eliminating the need for discrete mechanical fasteners. In a preferred embodiment of the invention, an improved aftermixer and gating apparatus includes a mixing body in which a flowable multi-constituent molding material is separated into a number of generally serpentine mixing passageways and reunited in a common mixing cavity before being conveyed through a fan-gate passageway to the mold cavity.

Abstract: A space portion processing method and apparatus for preprocessing a slide fastener chain before attaching parts forming a separable end stop such as a retainer pin and a separable pin at the space portion of a slide fastener chain formed by cutting and removing a row of elements for a certain length from a row of coil-like continuous fastener elements of thermoplastic resin attached around a core cord along each of the facing side edges of a pair of fastener tapes are disclosed. After the space portion is detected and positioned and the slide fastener chain is held on a bed, fusion of the element cut edges at the end of the space portion into the tapes and press-forming of the core cords is carried out simultaneously by using the same pressing means. The space portion processing method and apparatus for a slide fastener chain according to the invention enables the apparatus to be made simple and compact, allows processing efficiency to be improved, and processing costs to be lowered.

Abstract: An article of manufacture comprises a molded-plastic fitment such as one of the halves of a snap fastener molded in situ to a porous substrate such as a garment fabric. Various embodiments are described for the article, as well as dies for forming the same, and methods and a machine for making the same.

Abstract: In a method for continuously manufacturing slide fastener coupling elements, a molded strip of coupling element blanks is folded by a first folder unit about its longitudinal axis while still hot into a U-shaped cross-section to provide a folded strip of coupling element blanks each having a width larger than a predetermined width of each of the coupling elements as ultimately shaped. After having been heated by a hot-air blower, the hot folded strip of blanks is shaped by a second folder unit into slide fastener coupling elements of a finalized shape and dimensions through a plurality of bending stages in which the widths of the coupling element blanks are constricted stepwise by the second folder unit as the folded strip of blanks is fed therethrough.

Abstract: A method of supplying a thermoplastic material to a molding machine for molding the same into a desired formation on slide fastener tapes is disclosed, whereby a composite plastic material, consisting in such a predetermined ratio of a fresh supply of material and removed runners and sprues, is fed so as to enable homogeneous color distribution of the resulting element chain on the fastener.

Abstract: An apparatus of manufacturing a slide fastener with a separable end stop according to the invention includes: a step which is carried out while separating engaged stringers of continuous length which have space portions disposed at regular intervals in their longitudinal directions and which consists of conveying the separated stringers through an injection molding station; suspending the operation of conveying the stringers in such a manner that one of the space portions is disposed at the injection molding station; and simultaneously injection-molding upper stops and pins which constitute a separable end stop on the stringers at each end of the space portion.

Abstract: A generally planar object 22 subject to dimensional variations is centrally held in a mold by a deformable suction ring 20, and inflatable seals 8, 9 are urged against its opposite peripheral surfaces to define a cavity 17 for the injection molding of a precisely dimensioned edge frame 23. The dimensions of the rigid mold halves 2, 3 and the elasticity of the ring and seals are such that a wide range of dimensional variations may be tolerated in the object, which may be a curved automobile glass panel, a printed circuit board, etc.

Abstract: The invention provides method and apparatus for forming upper stops of a concealed type slide fastener. A concealed type slide fastener comprises a pair of fastener stringers each consisting of a fastener tape having a turn-up along one side thereof and fastener elements of thermoplastic resin secured to the turn-up. Portions of the elements are fused to form upper stops. In the method and apparatus of the invention, a pair of spaced projections are formed on a base and placed with respect to fastener stringers of a slide fastener or continuous fastener chain so that the projections pass between the stringers. The fastener elements are urged toward the projections while portions of the projections engage the arrest the element-mounting-side margins of the tapes to expose the interengaging heads of the elements so that only the interengaging heads are fused.

Abstract: A forms feed tractor belt includes drive members molded around a thin, flexible band at longitudinal intervals. To make the belt, slots are first punched at longitudinal intervals in at least one side of the flexible band. Drive members are then molded around the band at the slots except for at least one drive memberless interval at each end of the band. The ends of the band are overlapped so that the slots of the drive memberless intervals coincide. Final drive members are then molded around the slots of each pair of coincided drive memberless intervals to complete the endless tractor belt.

Abstract: The invention relates to superficial molding on glass sheets, by injection molding of plastic material.According to the invention, a glass sheet 1 is inserted in a mold comprised of two plates and which define a generally planar junction surface wherewith one part of the mold, which part is delimited by a hermetic seal, is evacuated, which enables the central part of the glass sheet to be held in place, and according to a feature of the invention, the superficial molding is delimited by a molding seal which is capable of accommodating variations in the shape of the glass sheet and which can withstand the pressure associated with the injection molding of the plastic material.

Abstract: The present invention provides a method and apparatus for fabricating non-linear side wall conveyor belting wherein the non-linear side walls are cured simultaneously with the conveyor belting with which they are associated, thereby providing a much stronger attachment than obtainable through use of conventional adhesives or a thermal bonding process. The method utilizes a mold adapted for forming side wall material into a non-linear shape and for simultaneously curing said formed non-linear side wall material together with uncured conveyor belt material. Fabrication is accomplished by placing uncured side wall material into the mold together with uncured conveyor belt material, forming the uncured side wall material into a suitable non-linear shape, and then simultaneously curing the non-linear side wall material with the conveyor belt material under suitable conditions of heat and pressure.

Abstract: A stamping apparatus disclosed deforms a filamentary material to provide coupling heads and the like at predetermined intervals along the length of the filament which is to be coiled and attached to stringer tapes for a slide fastener. The apparatus includes a pair of stamping rolls which are rotatable in opposite directions on their own axes simultaneously as they orbit about the axis of a rotor. A ring member rotatably connected to the stamping rolls is driven via the same power source as the rotor but rotates at a slower or faster angular speed than the rotor, the resulting angular speed differential being utilized to effect the rotation of the stamping rolls on their axes.

Abstract: A woven stringer tape of a slide-fastener half, designed to support a row of thermoplastic coupling elements molded around a carrier cord adjoining a longitudinal edge of the tape, has warp threads parallel to that edge traversed by a weft thread looped about the cord, at least two of these warp threads close to the core and in mutual phase opposition consisting of thermoplastic monofilaments with a melting point lower than that of the coupling elements. Upon the molding of the latter, these two thermoplastic warp threads are partially melted along surface portions in contact with the coupling elements so as to form notches in which the coupling elements positively engage for a firm anchorage to the fabric.

Abstract: The continuous casting of scoops upon tapes for a sliding clasp fastener which includes two casting rollers with peripheral cavities and an extrusion nozzle with juxtaposed tapes introduced between the nozzle and a first one of the rollers. The arrangement is such that molten plastics is introduced by the nozzle firstly into the cavities of the first roller ahead of the nip between the rollers and subsequently into the cavities of the second roller adjacent the nip. To ensure adequate solidification of the scoops before removal from the second roller the tapes are drawn off from said second roller at an angular position thereof beyond the nip.

Abstract: An invisible slide fastener includes thermoplastic slide fastener elements secured to folded-back portions of the mounting tapes. The slide fastener elements are molded onto the tapes so that integral fastening extensions of the fastener elements extend through an open mesh area of each tape. The slide fastener elements include an interlock structure which is particularly resistant to movement between the opposite rows of slide fastener elements.

Abstract: The invention provides a method and apparatus for injection-molding at least a first part of a plastics manifold element onto an extruded, panel-forming plurality of juxtaposed, hollow elements, comprising the steps of introducing into one set of ends of the hollow elements protrusions which extend from a core defining the shape of at least part of the interior space of the final manifold to be formed; clamping the region of the set of ends accommodating the protrusions between first and second mold members which, together with the core delimit the cavity of at least part of the final manifold; injecting plastic material into the cavity; and removing the core, and the mold members, whereby a strong bond is formed between the hollow elements and the manifold.

Abstract: One or more inner bands are employed to cooperate with an outer band and a cavity wheel or inner molding member wherein portions of the inner band or bands together with the outer band and the cavity wheel or inner molding member are utilized to continuously form the cavities for continuously molding articles. The inner band or bands are employed to form core members, intermediate cavity wall portions, and/or stripping members for the molding cavities.

Abstract: A method of manufacturing a continuous slide fastener stringer, comprising the steps of: providing a continuous stringer tape having a plurality of openings along a longitudinal edge thereof at regular intervals of a first distance d; then placing a part of the tape between a pair of mold members defining a number of mold cavities spaced at regular intervals of a second distance D slightly greater than the first distance d; then stretching the part of the tape until the openings in that part are aligned with the mold cavities; then injecting melted synthetic resin material into mold cavities, while the mold members are closed, to form on the part of the tape of number of the injection-molded coupling elements one at each of the openings; and repeating the preceding steps, except the first-mentioned step, for a succeeding part of the tape.

Abstract: An apparatus for forming coupling members of synthetic resin for application to a support tape in the production of a slide-fastener stringer comprises a forming wheel to which an endless band is fed to form mold cavities on the periphery of the wheel which are filled with synthetic resin. According to the invention, a further band is fed to overlie the first band and define undercut portions of the cavity to produce projections in the molded members which can engage when the latter are applied to a support tape. A continuous core can be fed to the drum periphery to be embedded in the coupling members as they are formed so that the row of coupling members is produced as a succession of teeth on this continuous element.

Abstract: Method of supporting a preformed membrane in an electrolytic cell, and apparatus therefor, which comprises casting in situ support plates about the open edges of the membrane.

Abstract: A continuous flexible metal band surrounding a molding wheel and rotating therewith engages the wheel through an arc less than 180.degree., e.g. 110.degree., and is maintained with a substantial inward radius of curvature throughout its entire length. This permits the employment of bands with cavities therein and having thicknesses several times greater than 0.001 times the diameter of the molding wheel without fatigue and failure of the band.

Abstract: Fibreboard panels and the like, useful as drawer fronts, cabinet doors, table tops, furniture parts, moldings, baseboards and the like are formed of compressed fibre panels or strips with an edge treatment forming a contoured or profiled edge surface. The wood fibres on the edge surface are heat seared and die pressed together to form a heat seared sealed surface of skin which does not require subsequent filling and further mechanical surfacing and which is more easily finished by the application of liquid decorating materials, paints, stains, printing inks and various colorants. The cellulosic fibrous blanks are mechanically preshaped to provide a contoured profile edge which is subjected to heat and pressure from a heated die which sears and seals together the fibres forming a skin over the profiled edge surface. The skin formation results in a reduction of time and labor that is required for any final finishing operations and provides a better appearance for the entire surface of the fibreboard piece.

Abstract: A process for making a panel having a supported member formed either of a simple or multiple glass window and a supporting part formed of preformed parts received on and at spaced locations around the glass window for supporting a light frame thereby to accommodate the panel for use as a window or door.

Abstract: A heating cylinder with a chamber therein is mounted on a base and has a discharge nozzle with an orifice therein, a plunger being movable into the chamber toward the discharge nozzle. A mold holder is supported on the base and has a mold including first and second mold members which jointly provide a mold cavity therebetween. The mold holder is pivotable between a first position in which the mold is held in contact with the discharge nozzle with a sprue in one of the mold members being held in communication with the orifice and a second position in which the mold is located away from the discharge nozzle. There is a means on the base for locking the mold holder in the first position.

Abstract: Fibreboard panels and the like, useful as drawer fronts, cabinet doors, table tops, furniture parts, moldings, baseboards and the like are formed of compressed fibre panels or strips with an edge treatment forming a contoured or profiled edge surface. The wood fibres on the edge surface are heat seared and die pressed together to form a heat seared sealed surface of skin which does not require subsequent filling and further mechanical surfacing and which is more easily finished by the application of liquid decorating materials, paints, stains, printing inks and various colorants. The cellulosic fibrous blanks are mechanically preshaped to provide a contoured profile edge which is subjected to heat and pressure from a heated die which sears and seals together the fibres forming a skin over the profiled edge surface. The skin formation results in a reduction of time and labor that is required for any final finishing operations and provides a better appearance for the entire surface of the fibreboard piece.

Abstract: Molded top stops for a slide fastener have inner edges extending substantially in alignment with the inner edges of the interlocking elements and have bottom edges extending at acute angles upward and away from the interlocking elements. Further, during the molding of the top stops, extra interlocking element sections and the like are trimmed by trimming edge features on a horn tip cooperating with an anvil portion of a die.

Abstract: A process for making a filter element for use in intravenous infusions, comprises positioning a filter fabric between two half molds and then injecting plastic material into the two half molds to provide a tubular filter element transected by the filter fabric. In order to promote bonding between the fabric and the plastic, and thereby to avoid the formation of a transverse plane of weakness in the filter element coincident with the plane of the fabric, the half molds are provided with spaced cutting means in the form of knives arranged in a peripheral series about the mold in such position as to penetrate the fabric at a plurality of spaced points when the mold is closed with the fabric between the mold halves.

Abstract: In a method of making separable sliding clasp fasteners, the interlocking elements of a thermoplastic material which are on the edge of a band of the fastener are placed in a mold such that thermoplastic material is injected into the mold and formed over a segment of the interlocking elements and allowed to solidify. By cutting the solidified material in the mold, the male parts of a separating device of the fastener are formed. A device for carrying out this process includes a mold comprising an upper half and a lower half. The lower half of the mold has on each side of its central axis, a longitudinal cavity and a band reinforcement track, adjacent to the cavity, and means for injecting molten thermoplastic material into the mold. Each of the cavities has a stationary part and a moveable part, with two lines of contact between the stationary and the movable parts, the purpose of which is to shape the two opposite lateral sides of the two male parts to be manufactured.