Abstract: In an injection mold for molding an article having an undercut at at least one end portion, the movable mold half has a slide core which defines the inner surfaces of the end portion and the undercut, and a main body which defines the inner surface of the other portion of the article. The slide core is divided, at the portion defining the inner surfaces of the end portion and the undercut, into a plurality of pieces in the direction perpendicular to both the ejecting direction and the direction in which the slide core is moved in perpendicular to the ejecting direction when the molded article is ejected from the mold. At least one of the pieces is adapted to be slid along an inclined surface which is at an angle to the ejecting direction larger than the angle at which the inclined surface or surfaces for the other piece or pieces are to the ejecting direction.

Abstract: An injection mold having a pair of stationary and movable molding plates, a plurality of sidewalls moved by one or more hydraulic cylinder assemblies disposed between the stationary and movable molding plates through inclined guide pins or guide blocks, a core member provided with a slanting surface and secured to the movable molding plate inside the sidewalls, and slide core members being movable in engagement with the core member. The respective sidewalls, and the sidewalls and the slide core members are connected by a connecting mechanism including link plates and connection plates so that the sidewalls and the slide core members are substantially simultaneously moved by at least one of the hydraulic cylinder assembly.

Abstract: The invention relates to an open type box-unit with multi-purpose application for the complex industrial construction of prefabricated houses, of buildings with different numbers of stories, and to molding apparatus for its production. The box-unit has a floor and roof structure with a spatially reinforced concrete framework consisting of two longitudinal frames and transverse frames; the cross bars of the longitudinal frames have a reinforced cross section asymmetrical to the cross section of the columns and an uninterrupted reinforcement in a closed shape. At modular distances in the cross bars of the longitudinal frames there are provided critical zones with cross sections doubled with regard to the cross bars and the columns of the end transverse frames. These critical zones are designed for the connection of the reinforcement of the cross bars and the columns of the middle frames having variable cross sections.

Abstract: Apparatus and method are described for injection molding of thermoplastic paint cans substantially similar in size and design to the conventional steel one-gallon paint can. The apparatus comprises a cavity element defining the exterior of the container body and a core mold element including a peripheral lip protruding into the interior of the can body at a point below the upper terminus of the top circumference of the container body, thus providing a peripheral upwardly projecting edge. The cavity element includes a plurality of cam elements which move cooperatively on separation of the core and cavity elements. The cam elements grip the ridge of the container and expand it outwardly sufficiently to permit the core element of the mold to be removed from the container without hindrance from the inwardly protruding lip.

Abstract: The invention relates to a collapsible core for a mould. The core comprises three relatively movable assemblies. The first assembly carries a cone, the second assembly carries an inner set of segments which form part of the core surface and engage the cone and the third assembly carries outer segments moved by inclined pins on the second assembly. As the assemblies are moved together the outer segments move radially outwards and the inner segments move axially in between them. Then the inner segments move radially outwards and the cone fills the center of the core. On reversal of the movement, the core is collapsed to enable it to be withdrawn from the moulded article.

Abstract: A mold, typically an injection mold, comprises a cavity member and a core member relatively movable between open and closed positions to define a first parting line and a molding chamber between the core and cavity members in the closed position. A sprue aperture is provided, communicating with the molding chamber to provide molding compound to the chamber. In accordance with this invention the cavity member defines forward and rearward portions movable between open and closed positions and proportioned whereby objects molded in the molding chamber can be removed from between the forward and rear portions when the cavity member is in its open position.

Abstract: A structural component having a curved wall, such as an aircraft fuselage pipe, has a grid structure formed of box frames produced by winding tapes of fiber reinforced synthetic material, so-called prepregs, onto mold bodies. These mold bodies are then assembled on a mandrel for covering with a planking and curing whereby the tapes are bonded together to form stringers intersecting with ribs in a grid structure and whereby the planking is bonded to the grid structure. The ribs are reinforced by fiber reinforced belt segments of synthetic material inserted into gaps between adjacent short ends of the mold bodies, whereby these belt segments are bonded to the ribs during curing. The belt segments ave a width corresponding to a multiple of the width of the stringers and hence protrude radially inwardly. Preferably, an edge reinforcing strip of fiber reinforced material is arranged alongside the radially inner edge of the belt segments.

Abstract: An injection molding system is provided with a plurality of wall segments which are displaceable substantially radially for forming a substantially continuous wall which forms an internal wall of a hollow region which is intended to be filled with molten molding material. In a preferred embodiment, the wall segments are urged into sliding communication with one another and sealable engagement with a further wall portion by operation of an actuator assembly which is provided with canted pins which cause the wall segments to be moved radially inwardly and outwardly in response to orthogonal displacement of the actuator assembly. The invention is therefore particularly suited for forming molded articles having hollow interiors and/or internally ribbed portions. In an embodiment where a slot is desired in the molded article, a slot core is arranged to communicate with the molten molding material, so as to form the slot, and an ejection mechanism.

Abstract: An apparatus for molding three concentric plastic materials into a composite body in which the mold includes a pair of molding blocks having reduced ends which define an inner cylindrical cavity into which a first material may be injected, a pair of tubular molding sleeves surrounding the molding blocks and axially movable relative thereto which define an intermediate cavity therebetween into which a second material may be selectively injected to form a second intermediate concentric portion of a composite body and a fixed molding cavity with which the inner and intermediate molding cavities are selectively aligned so that a third material may be selectively injected to form an outer concentric portion of the composite body.

Abstract: A mould which is used for the production by injection moulding of fittings which have an inner annular groove includes a divisible outer mould, a mould core and a mould ring. The mould core has a plurality of segments which can be folded together. In order to ensure with absolute reliability that the fitting does not remain clinging to the mould ring during removal of the fitting from the mould, the mould ring is connected to the mould core and is withdrawn together with the mould core from the fitting.

Abstract: An improved sheathing for use as a covering on a polygonal container having a plurality of adjustable support members for supporting the sheathing thereon. The sheathing comprises at least two adjacent pivotally connected panels having a vertical joint therebetween formed by an offset edge of one panel overlying an adjacent edge of the other panel. The panels include a mechanism for adjusting the angle between the panels comprising a pair of pivotally connected plates, each of the plates being pivotally connected to a respective one of the panels, and an adjusting screw threadedly mounted to the plates and extending towards the joint.

Abstract: An apparatus for forming a multisided upright concrete wall with inner and outer form set-ups including an arrangement for stripping said inner form set-up which has a multisided form wall from the cast concrete entirely which comprises at least one wedge means dividing at least one side of the form wall into two portions and wedged in between the two portions in a first direction during casting, and means for moving the wedge means in a second direction opposite to the first direction after casting and bringing the two portions to be nearer relative to one another, whereby the inner form set-up contracts and therefore entirely is spaced apart from the cast concrete.

Abstract: A bucket-shaped container having a rim opening smaller than the diameter of the side wall thereof is injected molded from thermoplastic material using a die set including a molding core which collapses to allow axial removal of the molded container from the mold. The molding core comprises a plurality of individual, wedge-shaped outer core sections which collectively form a continuous molding surface and are slideably mounted on a tapered inner core to allow axial sliding movement of the outer core section relative to the inner core. The sliding movement of the outer core sections on the inner core is provided by a plurality of keylocks which are fixedly secured in corresponding axial keyways in the inner core and which slideably engage corresponding axial keyways in the outer core sections.

Abstract: A molding device includes a multi-sided contractible inner form and outer forms that can be connected detachably to the inner form. The inner form has, at each side, a wedge-shaped spacer formwork board, on which are mounted a power means and a linkage mechanism, disposed between and connected detachably to left and right component formwork boards. The wedge-shaped spacer boards in all sides of the inner form can be pulled inward by individual power means through individual linkage mechanisms to leave space for the left and right component formwork boards to approach one another at all sides to contract the entire inner form.

Abstract: A molding apparatus for molding in place walls of a structure on a poured concrete floor or other base is provided with a central support member to which are movably attached four flat wall molds and four corner molds which cooperate with adjacent like apparatus and also with conventional exterior molds in forming a cast structure; the apparatus has actuating members for effecting retraction firstly of the flat wall molds and then of the corner molds toward the central support member upon completion of a casting operation and after hardening of the cast materials; the flat wall and corner molds are connected to the central support member by means of a plurality of lost motion connectors in such a manner that the aforementioned retraction is accomplished, after disengagement of locking devices, first by the flat wall molds and then, after a selected delay, by the corner molds; then, while in this position, the apparatus is removed and transported to another location where it will be set in its place in an expa

Abstract: A reusable form for manufacturing curb inlet drains in situ includes a central tapered key section to which drain forming elements are detachably secured. A lid section is also attached to the key section. The drain forming elements each have a generally horizontal shelf with an upwardly projecting curved neck flange segment. These segments form a circular neck which abuts the underside of the lid section when the form is assembled. The front drain forming elements define a mouth for the curb inlet drain. Except for the mouth, the sides of the form are closed by plates extending downwardly from the shelves. Following the formation of a curb inlet drain, the lid section is removed. In addition, the drain forming elements are detached and the key section is removed upwardly through a manhole opening of the curb inlet drain. Then, the drain forming elements are also removed upwardly through the manhole opening.

Abstract: A concrete mold core assembly for casting catch basins and the like has outwardly facing form panels disposed to form a box with at least two corner members being located at diametrically opposite corners of the box between spaced adjoining edges of the panels and a lid overlies the ends of the form panels and corner members. Each corner member provides opposite side surfaces defining a tapered wedge that matingly inter-engages with the spaced adjoining edges of the form panels such that when the corner members are moved outwardly the core assembly is expanded into its casting condition and when moved inwardly the panels and members are stripped from the hardened concrete. The lid is coupled to the upper ends of the corner members to be raised to casting condition when the members are moved outwardly and lowered to be stripped from the hardened concrete when the members are moved inwardly.

Abstract: An apparatus for consolidating an annular ring of uncured elastomeric material in a tread ring mould comprising a set of rigid segments in sliding end-to-end relationship to form a consolidation ring having a first small diameter for insertion of the segments into the elastomeric material in the tread mould and a second larger diameter at which the segments form a smooth, continuous consolidating surface, mechanical means for moving the segments from the first diameter substantially to the second diameter and a fluid pressure inflatable bag means which may be inflated behind the segments to apply consolidation force at the second diameter.

Abstract: A radially expandable core pin is disclosed for blow-molding a thermoplastic container having a body-portion and a neck-portion, with such neck-portion including a dispensing orifice and internal attachment means. The core pin is radially expandable to compression mold the internal attachment means of the container and comprises a plurality of circumferentially disposed core sections surrounding the central axis of the core pin. These core sections are radially movable between a normally collapsed position and an expanded position, and have outer surfaces which mate along their longitudinal adjacent sides when radially displaced to expanded position to form a substantially continuous neck-forming surface thereabout. The neck-forming surface is relieved in a predetermined pattern to form the internal attachment means of the container.

Abstract: A concrete form unit for casting an inside corner structure has a pair of form panels disposed generally perpendicular to each other and an elongated corner member disposed between spaced adjoining edges of such panels with an actuator having relatively movable parts including a first part connected to the midsection of a yoke and a second part connected to the corner member. The ends of the yoke are guidingly connected to the form panels, respectively, and the adjoining edges of the form panels are guidingly coupled to opposite sides of the corner member by slidingly interengaging surfaces, these surfaces defining a tapered wedge where the corner member mates with the adjoining edges of the form panels.

Abstract: A concrete ramp is, in cross section, in the form of an inverted U and is made in sections. The form includes a base the upper surfaces of which are inclined relative to the horizontal at an angle wanted for tread surface of the ramp. A pair of inner and outer side walls are provided for each side of the base and then are shaped and dimensioned so that their upper edges are horizontal, the height of the inner walls less than that of the outer walls. The walls of each pair are hingedly connected to the base in a manner enabling the outer walls to swing outwardly and the inner walls to swing inwardly. Power operated devices supported by the base are operable to hold the inner walls vertically or to pull them inwardly. A plate is supported by the inner walls in a manner permitting it to be lowered or raised as the inner walls are swung into or out of their operative position.

Abstract: Present invention relates to a metal mold device comprising a female die, a die frame having a hole and a male die assembly moving along an axis of the hole to produce a plastic molding having an opening with a partially waved inner sidewall. The male die assembly comprises a generally upwardly tapering central base having a rectangular top and four side slopes, a pair of opposed primary slide members and a pair of opposed auxiliary slide members. The primary slide members are strictly mounted on the opposed side slopes respectively while the auxiliary slide members are loosely mounted on the remained opposed side slopes respectively.

Abstract: A collapsible mold core having plural can actuated members surrounding a conical central core member, the members surrounding the central core member having slidable pins connecting adjacent members and molding apparatus including the core.

Abstract: A form unit to cast the inside surfaces of a corner of a concrete structure has a pair of form panels disposed generally perpendicular to each other and an elongated corner member disposed between the adjoining edges of such panels with an actuator having relatively movable parts including a first part connected by parallelogram linkage to each of the form panels and a second part connected to the corner member so that when the actuator parts are moved together the form panels are butted against the outer edges of the corner member and when the actuator parts are moved apart the form panels are separated from the corner member. Holding means retains the corner member against displacement toward the panels while the form panels are being stripped from the hardened concrete and latch means holds the form panels against relative movement while the corner member is being stripped.

Abstract: A mold defining a mold cavity for manufacture of an article, the mold comprising a plurality of mold side wall members, each of the side wall members including opposite end portions and including an inwardly facing surface comprising a mold surface for forming at least a portion of a side wall of the molded article. The side wall members are moveable from a closed position wherein the side wall members cooperate with said first and second end wall members to define a mold cavity conforming to at least a portion of the desired exterior dimensions of the article, and an open position in which each of the side wall members is displaced laterally outwardly of its closed position and away from the end wall members to a location in spaced relation from the end wall members.

Abstract: For casting a concrete inside corner wall structure, the corner is defined by a corner member to extend lengthwise of the corner with the adjacent edges of a pair of form panels that are disposed generally perpendicular to each other being butted against the outer edges of the corner member and a control unit is interconnected with the form panels and the angle member to retain this relationship between the panels and angle member incident pouring and hardening of the concrete. The control unit has actuator means associated therewith operable to move the panel edges into abutment with the outer edges of the angle member prior to concrete pouring and to strip both the form panels and the angle member from the hardened concrete structure.

Abstract: A core mold for bent pipes including a main body formed of a plurality of hollow cylindrical members connected to each other, the angle between adjacent hollow cylindrical members being fixable at any desired value. The main body may be mounted to a shaft through support members each of which consists of a main body fixed to the main body of the core mold and a shaft support member secured rotatably to the main body of the support member, the shaft support member being slidable along the shaft.

Abstract: A quick-release bayonet-type attachment between a core body and a plank of a concrete casting formwork, the core body being of oblong arcuate outline and holding in a central groove the eye portion of an anchor member, the bayonet-type attachment including a bayonet lock plate embedded in the core body and a cooperating threaded rod with a bayonet lock head. The lock plate and the cooperating head have non-circular cross sections, the lock plate being accessible through an upper bore portion of matching cross section, the bore portion below the lock plate having flexible walls and a rotationally offset non-circular cross section.

Abstract: A core body assembly for the creation of an oblong arcuate recess in a prefabricated concrete member and for the positioning of an anchor element in the recess, the core body assembly comprising two rigid inner core body parts which are enclosed within a flexible core body jacket, forming a bending connecting bridge and an adjoining anchor retaining groove with centering protrusions in its anchor positioning flanks. The inner core body parts have attachment inserts to which the end of a threaded rod can be attached, and they tilt against each other to clamp the anchor element, when the core body assembly is clamped against the formwork.

Abstract: A bucket shaped container having a rim opening smaller than the diameter of the sidewall thereof is injection molded from thermoplastic material using a die set including a molding core which collapses to allow axial removal of the molded container from the mold. The molding core comprises a plurality of individual, wedge shaped outer core sections which collectively form a continuous molding surface and are slidably mounted on a tapered inner core to allow axial sliding movement of the outer core sections relative to the inner core. Each of the outer core sections is also mounted for radial sliding movement on a mounting plate which circumscribes the molding core and is mounted for reciprocating axial movement relative to the inner core. Reciprocation of the mounting plate produces simultaneous axial and radial movement of the outer core sections throughout their entire lengths between an expanded molding position and a collapsed container releasing position.

Abstract: A collapsible inner form for making tubular concrete products has upper and lower sections with rigid casting faces, and flexible side sections which buckle inwardly when the internal form is collapsed. Jacks are used to push wheels in the upper and lower sections outwardly against the cast product, forcing the sections to their collapsed positions. The inner form is movable on the wheels for removal of the inner form from the solidified cast product.

Abstract: In a metal mold for molding a hollow product having inwardly tapered side wall with a stationary die plate for forming a bottom portion of the product, a core, and a cavity plate surrounding the core, the core has a truncated pyramid shape and first and second slide cores are provided between the core and the cavity plate. The core and slide cores are constructed such that at the time of opening the mold both slide cores are moved inwardly in an interlocked relation with retractive movement of the core thus leaving one end of the molded product for enabling removal thereof.

Abstract: A plastics gutter fitting (8, 11) has at least one transverse groove (10,17) receiving a sealing strip (16) and an inwardly turned clipping nib (9,15) extending across at least one end of a said transverse groove (10,17). The fitting is molded using a three part core of which two outer parts (4,4') can be moved convergently relative to a central part (3) for releasing a molding (8) therefrom. This molding method enables the reentrant where a clipping nib (9,15) extends across an end of a transverse groove (10,17) to be molded integrally in the fitting.

Abstract: A self supporting shrinking mandrel including an actuator with a plurality of legs, each terminated by a cross member. The legs and cross members are inserted into grooves of a plurality of support members. The grooves and cross members cooperate to hold the support members in place making the entire mandrel self supporting. The actuator is tapered in cross section along the longitudinal axis which causes a positive shrinking action as the support members are drawn toward the longitudinal axis when the actuator is withdrawn from the combination.

Abstract: An apparatus and method for producing a plurality of substantially dimensionally identical concrete structural modules. The apparatus facilitates the manufacture of a plurality of low cost molds of high dimensional accuracy which will consequently produce modules of high accuracy which can be interchanged, turned, and either horizontally or vertically assembled. A master pattern of the module having non-porous interior and exterior surfaces is positioned between inner and outer forms, the inner and outer spaces thus created are filled with a cementitious substance forming a mold having inner and outer mold segments with their mold faces formed against the non-porous pattern. The concrete molds are provided with various assembly mechanisms and shipped in matched sets to producers for use as forms in the production of the structural modules.

Abstract: A molding system for molding large diameter chimney liners of fibreglass reinforced plastic (FRP) utilizes a vertically oriented cylindrical mold for use in combination with a working platform mounted on a vertical ram. The mold is of modular construction, having a plurality of axially spaced-apart spiders, each spider being segmented into a plurality of adjoining tri-angulated segments to form a polygon, to the outer sides of which are attached chordal segments to complete the circular form of the spider. Vertically axially extending ribs interconnect the spiders, with a flexible skin being applied thereabout. The provision of expansion means on the spiders increases the diameter of the mold to its working diameter, so that, upon completion of molding a liner, the action of the spider expansion means is reversed, causing contraction of the mold sufficient to facilitate ready axial separation of the mold and liner.

Abstract: A method and apparatus for producing fishing lures incorporating hook hangers which utilize a bore formed in the lure body as part of the connection mechanism. Injection molding techniques are utilized to fill cavity molds having removable inserts therein.

Abstract: Apparatus and method for molding generally cubical building modules of concrete, the apparatus comprising both internal and external movably mounted molding components and preferably including mechanisms for advancing the components into molding position and for withdrawing the components from the molding position upon completion of the molding of a module. The method involves the use of such molding components and contemplates certain sequences in the advancement and withdrawal of the molding components for different portions of the modules. The outside mold parts comprise superimposed horizontal strips and alternative screw jack and reciprocating rod devices are provided for mounting and sequentially advancing and withdrawing the outside mold strips. Provision is further made for subjecting the concrete cast in the side walls to vibration.

Abstract: A mandrel for producing connecting sockets at the end of thermoplastic pipes, the mandrel containing a first and a second row of retractable segments and apparatus for actuating these segments. The apparatus comprises a first and a second actuating bush arranged so as to move axially on a central shaft. The segments of the first and second rows of segments are pivotably mounted on bushes by means of parallel, axially displaced joints. Support surfaces, which are orthogonal to the mandrel axis, serve to hold the segments during their radial movement.

Abstract: A mandrel for forming an annular groove in the bell of a plastic pipe which comprises a plurality of identically formed segments. The segments are radially urged identically from an initial position which is inwardly of the bell to an expanded position wherein the segments cooperate and interact to form an expanded ring of diameter greater than the pipe bell to thereby impress a circular groove therein. An actuating shaft rotatively reciprocates in unison a pair of cam plates, which cam plates are characterized by a plurality of arcuately curved guide slots formed therein. The segments include follower pairs which respectively ride within the guide slots to urge the segments from their initial positions to their expanded positions and back upon rotative reciprocation of the cam plates.

Abstract: A collapsible mold core comprises an inner core member, which remains out of contact with the inside peripheral surface of the molding, first and second pairs of mutually opposite, outer core members, which engage the molding and determine the shape thereof, and guides which converge toward the axis of the core and serve to guide the pairs of outer core members parallel to guide planes which are offset 90.degree. from each other and extend through the axis of the core. The four outer core members tightly adjoin each other, and the outer core members of the first pair have lateral wedge faces which extend parallel to the guides and at right angles to the guide plane of the outer core members of the second pair.

Abstract: The invention is concerned with an apparatus and process for curing tread and track belts. The apparatus comprises a plurality of inner segments which fit together to form an outer generally cylindrical mold face surface of an inner cylinder along with means for retracting said plurality of inner segments towards the axis of said inner cylinder and means for heating said plurality of inner segments. Also part of the apparatus is a plurality of outer segments which fit together to form an inner generally cylindrical mold face surface of an outer cylinder, said outer cylinder being coaxial with said inner cylinder and of generally equal length therewith, along with means for retracting said plurality of outer segments away from the common axis of said cylinders and means for heating said plurality of outer segments.

Abstract: A building construction system uses a mold set up at a construction site so that the external part of the mold is spaced clear of the internal part. Building elements including those which are functional in the construction operation are arranged around the internal mold part. Such functional elements include connecting rod anchorages around the lower region of the mold, and the like. The external mold part is moved into position near the internal mold part, and the mold is filled to form a casting. A lifting frame is arranged over the mold and adjustably connected to the connecting rods. Then the external mold part is moved away to release the casting, and the frame is lifted to raise the casting up over the mold for movement to a building site near the construction site.

Abstract: An expandable core for forming an internal recess in a molded part, composed of a stationary core pin having a generally conical outer surface and a segmented sleeve composed of two groups of lateral slides disposed around the pin with the slides of one group alternating with the slides of the other group. The conicity of the pin outer surface and the slide guidance along the pin are identical for all slides of the same group but are different from one group to the other.

Abstract: Hole forming devices have to be engaged between forms prior to pouring concrete. They are adapted to expand when in position to engage the inner faces of the forms thus holding them in position. The jack is a telescopic rod or tube having a heavy expansion spring surrounding same and normally urging the two portions of the hole forming device outwardly, but being held in the compressed or "set" position by means of a pin engaging through the two portions of the telescopic rod or tube. In one embodiment, when the pin is pulled, the sharpened ends of the rod or tube move away from one another, pierce the end caps of the forming device and engage the faces of the forms and at the same time move the end portions of the forming device outwardly into contact with the inner faces of the forms. In another embodiment, the ends of the rod or tube move outwardly and engage end pieces which in turn move outwardly and urge cylindrical saw-tooth end caps into contact with the inner faces of the walls of the form.

Abstract: Apparatus and method for molding generally cubical building modules of concrete, the apparatus comprising both internal and external movably mounted molding components and preferably including mechanisms for advancing the components into molding position and for withdrawing the components from the molding position upon completion of the molding of a module. The method involves the use of such molding components and contemplates certain sequences in the advancement and withdrawal of the molding components for different portions of the modules.

Abstract: A collapsible crypt form comprises an elongate rigid upper wall and two depending elongate rigid side walls joined at their adjacent margins by elongate rounded strips of resilient sheet material. Actuating means are connected to reinforcing rails at the lower edges of the side walls to extend them away from each other to operating position and retract them toward each other to reduce the effective height and width of the form for release from a finished recess. A back plate is held against the aft end of the body to prevent entry of flowable concrete and is disconnected from the body and removed from the recess after the body has been removed. A plurality of forms are placed in side by side spaced relation on a concrete slab with their forward ends in alignment with the forward edge of the slab and form plates are secured to the forms, locking them together and preventing loss of concrete.

Abstract: A portable apparatus for forming individual or multiple reinforced concrete, hollow core units of a modular building structure in interconnected side by side and/or high rise relationship which apparatus may be sufficiently collapsed to allow for easy removal from the formed and cured hollow core unit to again be used to form additional subsequent, interconnected, hollow core units of the building structure.

Abstract: Collapsible core assembly having retractable portion capable of producing plastic parts having an undercut. The core assembly comprises a segmented portion operably connected to an innercore pulling assembly whereby operation of the innercore pulling assembly first retracts the segmented core and thereafter pulls the complete core assembly out of the molded part.

Abstract: A core is provided, useful in the manufacture of closure caps, each closure cap having a top, dependent skirt and securing means, comprising intermittent or interrupted threads or hold-down lugs.