Abstract: An arrangement for the thermoforming of molded plastic articles from a continuous web of a thermoplastic material, and more particularly, a trim in place thermoforming arrangement in which the plastic articles are simultaneously molded and at least substantially or completely separated from the remaining thermoplastic web material. A high degree of alignment and precision is obtained between cooperating cutting blades employed in the trimming of the thermoformed articles, because of a unique self-aligning or floating support structure of at least one of the cutting blades operating in conjunction with the thermoforming apparatus. The self-aligning action provided for between the slidingly contacting cutting blades allows for an automatic compensation for any temperature changes and blade wear encountered during operation, and with only one movable part being required for the trim in place device.

Abstract: A method and system are provided for forming floppy disk envelopes. Envelope blanks are manipulated while attached to a continuous web of envelope material to facilitate handling and alignment of the blanks. Initially, fold lines are impressed into the envelope blanks to define the precise dimensions of the envelope. Envelope flaps are then partially folded to define a receptacle into which the disk media is then inserted. The remaining flaps are then folded and sealed, and lastly the folded envelope is detached from the continuous web. A particular apparatus for impressing the envelope blanks includes a male die, female die cavity, and mechanism for reciprocating the dies. The preferred score profile includes a pair of radii joined by a hinge section.

Abstract: A machine and method for manufacturing a disposable absorbent continence pad. The machine has a series of stations including a shell-forming station for forming a shell from thermoplastic material, a slitting station for forming slits in a facing material to be sealed to a shell in order to permit the facing material to adapt to the shape of the shell and a sealing station where the facing material and the shell are heat sealed together. The shell-forming station, slitting station and sealing station have special components to assure accurate molding of the shell and prevent wrinkles in the facing material. The manufacturing method embodies a series of processing steps as carried out at the aforesaid stations.

Abstract: Apparatus for stretching a parison or a preform which is formed by a blank and where the preform is preferably intended to be reshaped into a container. In accordance with the invention the wall of the blank is provided with two laterally displaced material regions. A mechanical moulding device reduces the material thickness in the material of the wall with commencement in the region thereof where the two material regions are laterally displaced relative to one another.Lateral displacement of the material regions and reduction by the moulding device of the material thickness are selected in order to allow, respectively achieve a reduction in thickness equivalent to that the thermoplastic material obtains when it is stretched so that material flow occurs. In one embodiment the lateral displacement is achieved by the moulding device.

Abstract: According to the invention, a mold assembly for molding an article is provided. The mold assembly is composed of at least male and female molds. At least one of the male and female molds is made of a hydraulic material composition having high strength containing a hydraulic material as a main ingredient. A molding face of at least one of the male and female molds is made of a substance other than the hydraulic material.

Abstract: A thermoformed plate having a rim adapted for embossing thereon a decorative pattern is provided. The rim has a generally curved profile which eliminates stress concentration points, providing greater stiffness and strength to the plate. A dual member mold useful in the production of the plate is also provided. The mold has corresponding male and female members, and contains an interchangeable annular insert in that portion of the surface of the male mold member that defines the rim of the plate. The desired decorative pattern for the plate is contained on the annular insert, allowing changes to be made in the rim pattern of plates produced by the mold without the need to replace the entire mold.

Abstract: A process is described for mechanized production of two-component dough products such as swirl cookies which includes forming an overall dough shape, embossing the top, filling the embossed area and ejecting the products onto a process conveyor.

Abstract: A number of distributed springs, fabricated from memory metal alloy, are connected to a die in a molding assembly. When heat is applied to the springs, they expand with sufficient force to mold a resin-impregnated composite material over a contoured mold form. The heat may be simultaneously applied to the composite material for achieving curing while molding occurs. Upon removal of the heat, the springs contract thereby allowing removal of a finished molded product.

Abstract: There have been provided synthetic resin food containers and the method and device for moulding the containers.The container has a bottom wall, a side wall extending at an obtuse angle to the bottom wall and a rim or legs extending from the undersurface of the bottom wall.The device comprises a male mould including a main body, a bottom forming portion received in the main body for vertical movement relative to the main body and a pressurizing portion disposed for vertical movement relative to the bottom forming portion; and a female mould for receiving a portion of the bottom forming portion.The method comprises the steps of forcing said portion of the bottom forming portion into the female mould to form the bottom of the container, raising the bottom forming portion and substantially simultaneously move the pressurizing portion to form the rim or legs on the bottom of the container.

Abstract: A die set is provided for forming a multi-compartmented tray from sheet material. The die set includes a female die assembly formed to include at least two mold cavities and a drawing surface bounding said mold cavities, a first compartment-former for pressing sheet material into a selected mold cavity to form a compartment therein, a second compartment-former for pressing sheet material into the remaining mold cavities to form compartments therein, and a draw ring for holding sheet material against the drawing surface during movement of the first and second compartment-formers into their respective mold cavities. The first compartment-former includes a first die for pre-forming the comparment, a second die for finish-forming the compartment, and a projection system for moving the first die relative to the second die in a direction toward the cavity to a leading position.

Abstract: Apparatus for forming deep containers from a thermoplastic material including a first mold portion having a cavity therein defining the side and bottom configuration of the container and a second mold portion having a plunger provided for reciprocation therein and arranged so that the plunger moves into the cavity. The first mold portion is provided with a first passageway that terminates adjacent to the cavity and in the parting surface of the mold portion and a second passageway that extends therethrough into the cavity adjacent to the bottom of the container. A control apparatus is provided that directs a vacuum through the first passageway securely holding the thermoplastic against the parting surface of the first mold portion.

Abstract: A process for making moldings with areas of marked final deformation from highly sensitive materials, such as tangled-fiber fleeces, in which the flat material is molded in the softened state between press molds. Prior to the actual molding process and independent of the desired molding of the final molding in a particular area and without any precompression of the material, the material is mechanically drawn between the corresponding press molds to such an extent that the resulting material flow roughly corresponds to the feed requirement for the final molding operation. The necessary auxiliary device comprises one or more push-rods with ram heads, which can be brought between the press molds when the press is in the open position and can be moved in the desired directions in the manner of an automated human fist.

Abstract: An apparatus and method is provided for simultaneously forming at least two interconnected deep-drawn containers in a single sheet of paper stock or the like. The apparatus includes a female die assembly formed to include a material-receiving cavity situated between spaced-apart first and second container-forming cavities. A blade assembly pushes a portion of the single sheet downwardly into the material-receiving cavity to provide a source of excess paperboard material from which the paper for adjacent containers can be drawn. A male die assembly moves to engage the female die assembly and draw at least the excess paperboard material deposited in the material-receiving cavity to form containers in the first and second container-forming cavities. A draw ring holds the sheet against the female die assembly during operation of the male die assembly.

Abstract: A system is provided for forming pizza dough and similar material into a pie shape by a series of progressively deeper tamping motions. Apparatus is provided for achieving such tamping, as are a conveyor to carry dough into registry with the tamping apparatus and then to a topping station and an oven.

Abstract: An egg carton thermoformed from a plastic sheet has a cover extension and a cell section extension formed by stretching the plastic sheet in the opposite direction from the sheet line from the direction in which the cover and the cell section are formed. Latching elements on these extensions lock the egg carton without the need for a latch flap. This permits the eighteen cell carton to be loaded on conventional egg loading machinery. The mold for forming the carton has formers which mate with cavities to stretch the lastic into the cover and cell section extensions.

Abstract: The ear plug (40) includes an elongate body with a rounded tip portion and of an elastic material enveloped by a deep-drawn sheath (41) of thin flexible plastics film material. Rearwardly the plug preferably has a neck portion from which the sheath projects in the form of a stiffer collar or flange. Production of the ear plug includes deep-drawing a thermoplastic film or foil into a sheath with desired thickness distribution, and filling the sheath with elastic material (53). Filling may take place simultaneously with deep-drawing, the body of elastic material constituting a die for deep-drawing in a forming hole (45), or after the deep-drawing. In the latter case, an elastic die body is used to advantage, the shape of which generally corresponds to that of the finished plug, for deep-drawing in a forming hole suited to the die body.

Abstract: Apertures are formed in plastic resin sheet material during a thermoforming process by shearing the heated plastic sheet between shear members which have cooperating shear faces extending in two dimensions in a plane perpendicular to the direction of movement of the thermoforming dies. The resulting apertures have a three dimensional configuration.

Abstract: A method of forming a cake from a sticky confectionary material based on sugar and cereals comprising the steps of transporting a layer of such sticky confectionary material having a uniform thickness on a surface of an endless conveyor to a position beneath at least one vertically disposed hollow cylinder whose wall is tapered at its lower end and inside which is a piston, advancing the cylinder downwardly so that it cuts through the sticky material until the lower edge of said cylinder contacts said surface and severs the sticky material within the cylinder from the layer; then advancing the piston downwardly to compress the severed sticky material to between about 40% and about 60% of its original thickness to form the cake, maintaining such compression for between 0.5 and 5.

Abstract: A press for forming sheet material into a shaped article comprising a frame, first and second complementary dies, a cam supported by the frame for reciprocally moving the first die along an axis between a first position axially spaced from the second die and a second position fully mated with the second die, the cam including a dwell period when the first die is in the second position. The press includes a bolster supporting the second die for axial movement between upper and lower limits, the bolster being axially spaced from the upper limit by movement of the first die to the second position. The press also includes a hydraulic power circuit responsive to the position of the cam for normally biasing the bolster toward its upper limit under a first hydraulic pressure and for biasing the bolster toward the upper limit under a second hydraulic pressure during the dwell period, the second hydraulic pressure being greater than the first hydraulic pressure.

Abstract: A molded, thermoplastic container having a pressure dome section in an end wall to permit the container to hold pressurized fluids. An integral dispensing spout may be provided which preferably is collapsible to nest within the container, and having sanitary seal means over the spout. An annular ring structure around the pressure dome section may be provided to permit the container to stand on an end during filling and storage. Method and apparatus are included for forming the pressure dome section in a previously molded thermoplastic end wall, for collapsing a dispensing spout to a nested position within the container, and for pressure testing the container.

Abstract: An apparatus for forming a paperboard receptacle includes male and female dies which draw the receptacle from a blank. The receptacle is moisturized during the drawing process to plasticize and lubricate the paperboard by injecting steam into one of the dies.

Abstract: Apparatus for shaping and cutting articles from a thermoplastic sheet and for stacking the articles in a stacking chute. A transporting device advances the sheet through the apparatus. The sheet is heated as it advances through the apparatus. A table is located downstream of the heater in the direction of advance of the sheet and is movable between a first position for shaping and cutting the articles and a second position for stacking the articles. A bearing pin is operatively associated with the table so that the table can be displaced by and pivoted about the bearing pin. A first guide device is mounted for being displaced perpendicular to the direction of advance of the sheet, with the bearing pin being seated in the first guide device. A bell crank drive is connected to the table via an articulated connection with the bearing pin for moving the table between the first and second positions.

Abstract: Apparatus and method for forming curved needlepoint canvases from initially flat perforated sheet by applying pressure to a first side of the sheet, thus driving and deforming it into an aperture in a die, and by supporting the opposite side of the sheet during deformation with a pressure pad which includes a recess into which the deformed sheet is driven.

Abstract: A structural article such as an automobile bumper includes a plastic body portion having an outer surface and a single metal sheet stretched to be completely disposed about and fixedly secured to the outer surface. The body portion provides a structural member and the metal sheet provides a continuous metal trim thereon.A method of forming the structural article includes the steps of compressing a sheet of metal and a sheet of heated softened plastic material within a mold so as to simultaneously cool the plastic material during the compression to set the molded plastic and stretch the metal about the outer surface of the molded plastic.An apparatus for forming the structural article includes a female mold portion including a clamping frame disposed about the periphery thereof. The clamping frame includes toggle clamps for clamping the peripheral edges of the sheet of metal to the periphery of the female portion.

Abstract: A machine and process for continuously thermoforming molten thermoplastic sheet are provided requiring precise synchronism in the interaction between opposed successions of circulatable tooling steps. A single motor for all the driving mechanisms achieves the desired synchronism and a driven succession of tooling steps itself drives the opposed succession.

Abstract: A deep frying basket has a pair of welded wire spring baskets which nest together to define a dish shaped space between them. A pair of more or less spaced parallel wires are welded to each of the wire spring baskets, one pair being welded to the inside bottom of the inner basket and the other pair to the outside bottom of the outer basket. In one embodiment, the two pairs are hinged together on one side of the baskets and formed into handles on the other side of the baskets. At least one pair of the wires is shaped to form a stand which facilitates a loading and unloading of a food product in the defined space.

Abstract: A method and apparatus are disclosed for imparting a desired shape to a paperboard blank. The blank is formed between two dies for a sufficient length of time and with sufficient force to set the form, while moving the dies in tandem along a predetermined portion of a reciprocation path. Because the formed blank remains in dwell while the dies are moving in tandem, it is not necessary to hold the dies stationary to ensure permanent formation of the blank. This allows greater production speeds.

Abstract: A method and apparatus for manufacturing a cup formed of a thermoplastic resin foamed sheet material and having a lip, the side wall and bottom of the cup being integrally formed, the lip extending outwardly from the mouth portion of the cup and being bent at its end radially inwardly towards the side wall. The method includes forming a rim extending outward from the mouth portion of the cup and having a downwardly extending end, providing a bending furrow on the outer periphery of the side wall at a level below the rim, and bending the rim, as it is heated, at the bending furrow. The apparatus comprises a mandrel block adapted to hold cups and rotatable and axially slidable, a hot blade or cutting blade movable toward the mandrel block and adapted to form a bending furrow for bending the rim, and a lip forming tool having a lip forming groove adapted to be heated.

Abstract: An apparatus is provided for thermoforming a plurality of protrusions in a plastic sheet. The thermoforming apparatus comprises a pneumatic press having a pair of male and female die plates with respective projections and cavities. One of the die plates is heated. The other die plate is cooled. The cooled die plate is provided with vacuum to ensure that the thermoformed plastic sheet is held against the cooled die plate upon the opening of the press to, in turn, ensure the cooling of the plastic sheet prior to its removal.

Abstract: A process and associated apparatus for forming a foam plastic article using a mold with a mold cavity and a pair of electrodes across which an RF field may be impressed. The foam material that is to be processed is inserted into the mold and is then compressed. The compression may be at least on the ratio of 2 to 1 and perhaps as high or higher than 8:1. An RF heating field is applied while maintaining the foam material compressed and after the heat is terminated, the foam material is permitted to expand to conform to a mold shape as the material cools. This pre-compression step enables substantial reduction in processing time.

Abstract: The packaging machine has a molding station comprising a reciprocating molding die for shaping thermoplastic sheet material to form packaging containers. Reciprocating drive is transmitted to the molding die by first engagement means provided laterally thereon and cooperating second engagement means provided laterally of the moving path of the molding die and opposite the first engagement means. The molding die may be moved into a retracted position at one end of its moving path, and when in this retracted position, the first and second engagement means are disengaged so that the molding die and any members secured thereto may be readily removed for replacement thereof and/or of molding inserts provided in a lower part of the molding station. In a preferred embodiment, the first and second engagement means are formed by a driving chain and engagement members, respectively, the engagement members being shaped to engage the chain links.

Abstract: An apparatus and method are disclosed for forming a multi-compartmented tray from a sheet material without tearing or bowing. At least a portion of one compartment, and preferably the entire compartment, is formed in advance of other compartments. The apparatus for doing so comprises a preformer on the male die for forming the first compartment before the rest of the male die engages the workpiece.

Abstract: A mold assembly for forming a dough mass into a unique pizza shell. The molding method and apparatus are operable to form the pizza shell from a preestablished, pre-measured quantity of dough sufficient to fill the mold cavity completely, but to obviate extrusion of excess dough from the mold. Thus, material is conserved and wasteful trimming operations are eliminated. The selected mass of dough used is correlated with the specific volume of the mold cavity to ensure complete filling while avoiding "overrun". Controlled spacing is provided between the cooperating dough-shaping mold elements so that air may escape from the mold cavity during compressive closure of the mold while the dough is retained to prevent extrusion. The shell itself is characterized in that it is not merely a flat sheet, but consists essentially of a planar base sheet bounded by a circumambient, integrally-formed, upstanding rim, marginal dam, or edge.

Abstract: A mechanism for clamping a web of thermoplastic material against the face of a female mold prior to closure of the mold includes a clamping ring assembly mounted on the machine frame for movement relative to the frame independently of the molds. The clamping assembly is driven to and from its web clamping position by a cam mounted on the rock shaft which drives the molds between their open and closed positions and a constant radius section on the cam holds the clamp in its clamping position throughout a substantial portion of the operating cycle.

Abstract: The temperature of upper and lower parts of a forming tool making deep-drawn thermoplastic articles is controlled with a system which performs the steps of passing a coolant of predetermined total volume through the upper part and the lower part of the forming tool; measuring the temperature of the upper and lower parts; determining the actual temperature difference between the upper and lower parts; comparing the actual temperature difference with a predetermined desired temperature difference; generating a signal representing the magnitude of deviation between the actual and desired temperature differences; and, as a function of the signal, increasing the volume of coolant passing through one of the forming tool parts and decreasing the volume of coolant passing through the other of the forming tool parts for reducing the magnitude of deviation while maintaining the total volume unchanged.

Abstract: A deep frying basket has a pair of welded wire spring baskets which nest together to define a dish shaped space between them. A pair of more or less spaced parallel wires are welded to each of the wire spring baskets, one pair being welded to the inside bottom of the inner basket and the other pair to the outside bottom of the outer basket. In one embodiment, the two pairs are hinged together on one side of the baskets and formed into handles on the other side of the baskets. At least one pair of the wires is shaped to form a stand which facilitates a loading and unloading of a food product in the defined space.

Abstract: Apparatus for stretch-forming a heat softened sheet of thermoplastics material. The apparatus includes a stretching tool and means to move the stretching tool relative to means holding the sheet so as to stretch the sheet in a preselected direction with the tool. The stretching tool includes a plurality of blades having edges for pressing against the sheet to stretch the sheet and a cam to move the blades transversely away from each other to stretch the sheet transversely of the preselected direction as the tool is moved to stretch the sheet in the preselected directions.

Abstract: Apparatus for molding curd in calibrated portions, a mixture of curds and whey, introduced into a hopper, fills perforated tubes in which the whey is separated from the curd and becomes compact. A plate closing off the base of the tubes retracts periodically and the curd drops abruptly by a predetermined height onto a subjacent plate, which is sliced by the first plate returning to its original position. The slices of curd are then transferred into one of the molds with a plurality of cells. This is applicable to the manufacture of cheeses of small size.

Abstract: A machine for crimping tire bead rings in which an inner die member has grooves for holding the bead rings in the area of the bead splices and an upper die member engages the outer surface of the bead rings in that area. The die members are compressed with sufficient force for a sufficient period of time so that the strands of the bead rings are held together by the insulating material around the strands in the area of the bead splices. The side portions of the grooves control the spreading of the bead rings and may be flared to compress and then release the bead rings. The grooves of the inner die member may have movable inserts for ejecting the bead rings. The upper die member may also include grooves in mating engagement with the grooves of the inner die member for enclosing the outer portions of the bead rings at the splice area and provide for release of the bead rings after crimping.

Abstract: This relates to the thermoforming of can bodies for use in packaging beverages under pressure from polyester sheet material, preferably PET. In accordance with the invention, a forming gas is applied to the periphery of the clamped sheet portion in radially outwardly spaced relation with respect to an associated mold cavity and the sheet material is billowed up into a large cavity formed in the clamp so as to provide for high stretching and orientation of the peripheral portion of the sheet before the sheet is directed into an associated mold cavity. Further, a plunger which normally forces the billowed or initially stretched sheet into the mold cavity may be constructed so as to be radially expandible to thus positively radially expand the sheet material within the mold.

Abstract: An apparatus for forming a thin-walled article comprising a frame providing a forming station for positioning a preheated sheet of thermoplastic material, first and second mold sections mounted on the frame in opposed relation with the forming station disposed therebetween, the first mold section having a forming cavity therein, the second mold section having a forming portion insertable in the forming cavity of the first mold section when the mold sections are displaced toward each other, the forming portion of the second mold section having at least one wall cooperable with at least one wall of the forming cavity of the first mold section when a preheated sheet of thermoplastic material is positioned at the forming station and the mold sections are displaced toward each other for sequentially shearing a blank from the preheated sheet of thermoplastic material and compressing the blank between the mold sections to cause the blank material to flow and form the article, means for ejecting the formed article fr

Abstract: An egg carton made from expanded polystyrene with a nonexpanded skin on one side includes integrally formed cover and tray portions interconnected together by a pair of hinges adjacent opposite sides of a hingeband. The tray is divided into a plurality of cells by a plurality of partitions. At least some of the partitions have a top flap portion hinged to the top of the partition by the skin of the polystyrene. Each cell further has a pliant inside surface provided by one or more grooves in the interior cell walls. A post extending from the inside surface of the cover is formed opposite a tray support surface using a thermo molding method by which a protrusion in a top mold is inserted into a nonvented cavity of a bottom mold. A pair of integrally molded hinge posts extend above the hingeband a distance less than the width of the hingeband between hinges and seat into a groove in the hingeband when the top is in closure relationship to the tray.

Abstract: A mold assembly for forming a dough mass into a unique pizza shell. The shell is characterized in that it is not merely a flat sheet, but consists essentially of a planar base sheet bounded by a circumambient, integrally-formed, upstanding marginal dam or edge. The mold assembly, which includes intercoupling pizza-shell-forming platen and matrix means, carries heater means in the platen for applying heat to the contacting face of the dough mass during compression shaping thereof thereby partially to cure and thus to fix or set the dough in its ultimate converted configuration.

Abstract: A molding tool for making articles by deep-drawing a heated thermoplastic foil includes a matrix having an inner wall face defining an opening, a mold defining a mold cavity aligned with the opening, and a depressor movably received in the opening of the matrix for clamping marginal portions of the foil during molding operation. A heat conducting sleeve is immobilized in the opening and surrounds the depressor. The outer face of the sleeve and portions of the inner wall face of the matrix define an annular chamber which surrounds the sleeve. A seal is provided between the matrix and the sleeve for rendering the annular chamber fluid tight. Channels are provided in the matrix for introducing a coolant into the annular chamber.

Abstract: An inventive apparatus for molding a toothed pulley is equipped with an upper plate, a lower plate, and a punch attached to the bottom surface of the upper plate for vertical movement, in which a die holder is provided on the lower plate, and a plurality of dies, formed to include tooth molds having different, increasing tooth heights from one die to the next, are arranged vertically in the holder.

Abstract: A process and apparatus is disclosed for thermoforming an all plastic carton used to house a fluid with integral, kidney-shaped depressions in adjacent side walls of the carton to serve as handle members to aid in pouring the fluid contents from the carton. A pair of mandrels are inserted through opposite ends of a tubular enclosure formed from the carton blank. The mandrels are provided with a toroidal shaped cavity where they meet inside the enclosure. The enclosure is heated and a pair of complementally shaped, dies are rotated exteriorly of the enclosure into the toroidal cavity in the mandrels on adjacent sidewalls of the carton to form the handle depressions.

Abstract: Apparatus for producing pastry comprises a plate having a plurality of mold cavities arranged in a regular pattern. Each of the cavities has at its upper rim an upwardly projecting cutting edge. A sheet of dough is laid over the plate and pressed toward it by a flat plate or rolling pin so that the cutting edges cut out individual dough pieces, one in each mold cavity. The dough pieces are pressed into the cavities by cup-shaped elements carried by a rigid support and arranged in the same pattern as the mold cavities so that a cup-shaped element enters each cavity. The distance the cup-shaped elements enter the mold cavities is limited by adjustable screws on the support. The cup-shaped elements are of material having good heat conductivity and thermal capacity and are left in the mold cavities during baking to assure uniform baking of the pastry.

Abstract: A thermoforming machine having a plurality of stations arranged in a circle, i.e., a charging station for insertion of a plate or sheet of thermoplastic material, a heating station, a forming station and a discharging station for the finished part (which discharging station may be the same as the charging station) and a like plurality of clamping frames for the thermoplastic material which frames can be pivoted from station to station, and with the forming station being provided with a height adjustable mold table for accommodating a deep drawing mold and a height adjustable blow box. To raise and lower the mold table, a pair of hydraulic cylinders are symetrically arranged on the respective sides of the mold table with the cylinders being essentially vertical in the interior of the blow box. Each of the cylinders and its associated piston rod is connected between a stationary support plate for the mold table and the mold table.

Abstract: A shape-preserving device which is attached to the top and bottom mold section of a thermoforming machine which reciprocatingly thermoforms articles from a heat-softened plastic sheet. The device includes a cavity mold attached to one mold section and a remolding shoe assembly attached to the other. The remolding shoe assembly includes a floating remolding shoe attached to the outer end of a piston rod connected to a pressurized fluid-actuated pneumatic cylinder which is in unimpeded flow communication with a source of compressed air.

Abstract: An injection mold comprises an outer mold structure defining an abutment surface and a core axially slidable in this structure between a molding position and a second position. The core defines a mold cavity with the outer mold structure in the molding position to mold a tubular end portion of a synthetic thermoplastic resin article therein. The core includes an annular rib defining an internal peripheral annular groove of the end portion and an end to which a mold sleeve is axially immovably connected. The mold sleeve has an end face facing and conforming to the abutment surface upon axial sliding of the core into the molding position. The mold sleeve and core end have converging confronting surfaces defining an annular gap tapering toward the core end, the annular gap defining a free end of the tubular end portion extending outwardly from an annular section thereof surrounding the groove.