Abstract: The present invention relates to an index/seal pin indexed precisely in a resin transfer molding die to assure the desired resin-to-fiber ratio in the mold part, and, thereby, to produce reliably and consistently a part of minimum weight with adequate strength. The index/seal pin seals via replaceable O-rings on the threaded stem of the pin to prevent low viscosity resin from exiting a mold cavity and invading the threads, bolts, pins, or other elements of the internal mandrel. The pin also assures accurate positioning of a mandrel in the die cavity while it allows the entire inner mandrel to be enclosed and sealed within the mold cavity, simplifying the sealing system.

Abstract: The present invention relates to a seal pin indexed precisely in a resin transfer molding die to assure the desired resin-to-fiber ratio in the mold part, and, thereby, to produce reliably and consistently a part of minimum weight with adequate strength. The index/resin seal pin of the present invention for RTM mold dies is novel in that it provides the seal (via replaceable O-rings) on the threaded stem of the pin to prevent low viscosity resin from invading the threads, bolts pins, or other elements of the internal mandrel. The pin allows the entire inner mandrel to be enclosed and sealed within the mold cavity, simplifying the sealing system. The invention also relates to a method for using the seal pin in a resin transfer molding process.

Abstract: A metal mold for molding a slider of a slide fastener is provided. The metal mold comprises upper and lower mold cavities for molding portions of the slider, with the upper and lower molds moving up and down relative to each other in order to open and close the mold. The mold further comprises at least two sliding molds for molding portions of the slider not molded by the upper and lower molds. The sliding molds are capable of being removably introduced into the upper and lower molds from their front and rear sides when the upper and lower molds are in tight contact with each other.

Abstract: A mold has outer mold parts and inserted molding material cores. Together, the parts and cores form a mold cavity. The inner cores of molding material are arranged in several layers one above the other. The inner cores are clamped in between the outer mold parts and a final covering core of mold material. A continuous clamping force is applied between the parts and cores. The mold cavity is formed by surfaces of the outer mold, surfaces of the inner cores and the covering core.

Abstract: A window buck having members forming a frame with the members including adjustable components enabling use of the buck in walls under construction of different thicknesses. Extruded front and rear components of each buck member are adjustably interengaged with one another and fixable in a desired relationship to suit the wall being constructed. External channels formed in the buck members are open lengthwise to permit reception of angular connectors for joining the buck members at their intersecting ends. The connectors may be of reusable rebar and removable upon completion of the wall. The components of each buck member are lockable by inserted fasteners. A modified window buck includes a central component for use in walls of extraordinary thicknesses. A further modified window buck may include buck members of unitary construction.

Abstract: A building block for erecting walls, houses or other buildings is provided. The block is made of a special mineral mixture and has at least two relatively parallel channel type hollow spaces passing therethrough. The hollow spaces of the building block are defined by can shaped metal or synthetic plastics profiles. Also a mold with longitudinal and face walls is provided, in particular for producing such a building block. The mold has a frame shaped construction of angle pieces and is arranged on a working plate.

Abstract: A three piece full port ball valve for use with a form for producing a cast concrete article is provided wherein the housing of the valve has been modified by creating openings through the valve housing to access the flow opening in the ball member for clearing concrete slurry therefrom after the form has been filled. Additional openings in the housing at other locations can be created for cleaning around the ball member and the inside of the housing.

Abstract: A container for cross-linking composite materials on dental bridges and arches and on individual teeth, comprising: a plurality of plate-like elements which can be stacked and clamped together, at least one of the plate-like elements, which is internal to the plurality of plate-like elements, being constituted by a plurality of blocks which can be removed independently of each other to form an area which is suitable to constitute a mold into which it is possible to place a metallic structure on which the elements of a dental prosthesis are to be formed, the at least one of the plate-like elements and a plate-like element that is adjacent thereto in an upward region and constitutes the top plate-like element of the container being both made of a material which is transparent to light.

Abstract: A method for casting a plastic die including constructing an open ended container having a floor configured to the desired contour shape of the die. A plurality of elongated cores having tapered and arcuate peripheral edges are spaced within the container and secured in place by traversing members. A cavity is formed in the container therebetween for the injection of hardenable material.

Abstract: A compression molding apparatus includes a mold of a first material having a first coefficient of thermal expansion and a plug of a second material having a second coefficient of thermal expansion different from the first coefficient of thermal expansion. The mold has a cavity into which the plug is placed such that the mold and plug are disposed relative to one another providing a gap therebetween having a first volume for holding a body that at least partially fills the gap when the mold and plug are at a first temperature and for molding the body into a molded product when the mold and plug are subjected to a second temperature that causes one of the first and second materials of the mold and plug to change in size more than the other and thereby change the gap to a second volume different from the first volume and compress the body.

Abstract: A process of molding of a rubber tread making it possible, after molding grooves, to strip the mold without rupture of connecting elements molded in the grooves. A molding element for molding a groove pattern in a rubber tread, the groove defined by at least two main opposite walls joined by at least one molded rubber connecting element, the molding element being designed to project from a molding surface of the mold and presenting at least one opening for molding a connecting element during molding of the tread. The molding element is constituted by the assembly of a first part forming a support, intended to be fastened to a piece of a mold by appropriate means, and of a second part constituted by at least one piece forming a key. Each key is disengaged from the support in order to strip the molding element from the mold.

Abstract: The invention relates to a set of parts for use in building, comprising a plurality of separate parts which are assemblable to provide a former for defining a desired configuration in a set settable material, characterised by at least two interengageable surface forming parts (2, 3), and by a thrust part (4) which maintains the surface forming parts (2, 3) in an assembled position, and by the thrust part (4) being removable to allow the surface forming parts (2, 3) to be moved from the set settable material whereby to leave the desired configuration (7) in that material (6).The invention also extends to a constructional method, and to a building or part thereof constructed using the set of parts described.

Abstract: In a mold for molding a slide fastener slider, a first template has a first part of a cavity for molding a rear section of an outer contour of the slider body except an upper surface portion of an upper wing and also has a first core for molding a rear section of an element guide channel of the slider body; a second template which is movable toward and away from the first template has a second cavity part for molding a front section of the outer contour of the slider body and also has a second core for molding a front section of the element guide channel; and a third template which is slidable on the first and second templates has a third part of the cavity for molding a pull-tab attaching lug of the slider body and an outer contour of the upper surface portion/shape of the upper wing. For molding, these templates are brought together to form the cavity, and then molten molding material is poured into the cavity via a channel and a sprue.

Abstract: A mold box is flexibly mounted to a product forming machine having upper and lower vertically displaceable beams. A feed drawer dispenses concrete material into the mold box while a vibration system vertically vibrates the mold box while dampening horizontal vibration. The vibration system is driven by a single drive shaft that actuates first and second vibrator rods while at the same rotating a counter-weight in a counter-rotating direction. A set of alignment brackets lock the mold box into a predetermined aligned relationship while being mounted in the product forming machine. The bottom side of each mold box is mounted to the product forming machine in the same relative position to reduce machine readjustments. A set of telescoping legs hold the feed drawer assembly variable distances above the mold box. A unitized pallet feeder quickly moves pallets one at a time from an "on-deck" position to a "receiving" position underneath the mold box.

Abstract: A method for casting a plastic die including constructing an open ended container having a floor configured to the desired contour shape of the die. The open ended container is segmented by longitudinal members and traversing members. A plurality of box-shaped cores are spaced within the container and secured in place by the traversing members. A cavity is formed in the container therebetween for the injection of hardenable material.

Abstract: The window buck is made of extruded irregular shapes consisting of a combination of cellulose and polymer compounded specifically to be used in connection with building walls of poured concrete. The combination desirably is a mixture of approximately 70% cellulose and approximately 30% polymer. The cellulose is preferably sawdust, and the polymer preferably is polyethylene.

Abstract: A molded fiberglass-reinforced resin boat hull provided with in situ holes to accommodate through-hull fittings, such as a fitting adapted to receive a rudder post. The boat hull is molded on a female mold having locating holes drilled therein in registration with the holes to be formed in the hull. Anchored by a bolt locked in each locating hole is a plug of non-stick material which projects above the mold and has a configuration defining the hole to be formed in situ in the hull. Laid down on the female mold and surrounding the projecting plugs are the reinforcing fiberglass materials and flowable uncured resin for creating the hull. When the resin is cured, it is not bonded to the plugs and the plugs and their anchoring bolts are removed to expose the in situ holes. The finished hull is then withdrawn from the female mold.

Abstract: A method for manufacturing a ferrule having butt end face on the front and positioning holes on both sides in the width direction and formed with plurality of fiber holes for inserting optical fibers, arranged in such a manner as to be inclined in the thickness direction, by using at least two molds which are arranged in an opposed manner and either or both of which can be moved in the opening/closing direction. Each of at least two molds has a first forming wall for forming the butt end face and a second forming wall for forming a working portion for applying a pressing force perpendicular to the butt end face at the rear of the ferrule. A core for forming the fiber hole and molding pins for forming the positioning holes are arranged in parallel and held in such a manner as to be inclined at a predetermined angle .theta. in the thickness direction of the ferrule molded by at least two molds.

Abstract: Process for the production of thermoinsulating structural elements, which includes:a)producing by thermoforming a cell made of thermoplastic material;b)pulling on such cell on a male die half shell;c)closing the die with a negative half shell suitable to form a cavity between the half shells,d)inserting in the cavity bored hollow elementse)filling the cavity with foamed pearls in thermoplastic polymers;f)sintering the pearls with steam fed through hollow elements.g)cooling and extracting the hollow elementsh)extracting the structural element from the die.

Abstract: A concrete building block (2) has complementary projections (10) and recesses (12) to cause it to interlock with other blocks (2). A T-shaped channel (16, 26) on the top surface (4) receives an anchor member (32). A projecting end (36) of the member (32) may be secured to an anchor cable (104). The ends of a metal cable (22) are embedded in the block (2) with an eye portion (24) projecting into an increased depth channel portion (20). The lower surface (6) of the block (2) has parallel channels (28) for receiving the tines of a forklift. The channels (16, 28) have breakaway walls (18, 30) at their outer ends, which are not broken away unless the channels (16, 28) are to be used. The walls (18, 30) prevent concrete from flowing out of the channels (16, 28) when reinforcing concrete is poured through vertical openings (14) in the block (2). In molding the block (2), slugs (86) are releasably attached to opposite mold walls to form the openings (14).

Abstract: A fan blade mold is disclosed having a center shaft molding unit and a blade molding unit disposed around the center shaft molding unit and defining with the fan blade mold a plurality of blade molding cavities around the center shaft molding unit for molding the blades of the fan blade, the center shaft molding unit having a longitudinal center cavity for molding the center shaft of the integral fan blade to be molded, a plurality of knock-out pins spaced around the center cavity for knocking out the fan blade and for molding a respective circular dent on a hub of the fan blade, and a reference line raised from the top side and aligned with one lateral side of one blade molding cavity, the knock-out pins being respectively disposed at the radial lines which pass through the point at 1/3 of the radial width of each blade molding cavity measured from the left lateral side of each blade molding cavity.

Abstract: A ring-cake preparation system is adapted for use in association with a ring-cake and a ring-cake container. The ring cake container is formed in a cylindrical configuration. A plate with a post is positioned within the cake container. The apparatus includes at least one disc formed in a planar circular configuration with a circular aperture at its approximate center point. The diameter of each circular aperture measures between about eighteen and twenty percent of the diameter of each disc. Each circular aperture is adapted to permit the passage of the post of a ring cake container. At least one rim is formed in a cylindrical configuration and is positioned around the periphery of each disc. The rim is positioned in a perpendicular orientation with respect to the plane of the disc. The width of the rim measures between eight and twelve percent of the diameter of the disc. The disc intersects the rim at its approximate center point.

Abstract: The invention provides apparatus for use in connection with the casting of bodies, e.g. of concrete panels, which are to contain within them one or more anchor members which extend towards the surface of the body and are accessible within recesses formed in said surface.

Abstract: A wheel cover mold assembly is provided for all wheel cover styles of a particular wheel diameter and mounting system. The mold assembly includes a top and a bottom base. The top base carries a mold cavity plate and the bottom base carries a mold core plate. The mold cavity plate and mold core plate include cavity surfaces defining the configuration of a specific wheel cover. The bottom mold base additionally includes a core retainer plate, inserts and/or cores which define, in cooperation with the mold core plate, mold cavity portions for a wheel cover mounting system common to various wheel cover styles. If the mounting system comprises an annular grip ring, for example, the inserts or cores cooperate with the core plate to form a grip ring receiving channel on the inner face of the wheel cover. If the mounting system includes individual mounting clips, the mold inserts configure the mold cavity for clip receiving sockets which project axially from the inner face of the wheel cover.

Abstract: A method and mold for making a wheel of a roller skate including a plurality of circumferentially spaced apart generally axially extending curvilinear paths. A speed skater, traveling a predominately circular course with such wheels properly aligned on such skates, is able to use air moving past the skater to increase skating speed. As air enters the curvilinear paths of the wheel the direction of air flow changes. In this manner, momentum is transferred from the moving air to the spinning wheels, thus increasing the number of revolutions of the wheel and the speed of the skater. The mold may be formed of polyurethane and use flexible fingers to form the curvilinear paths of the wheel.

Abstract: A baking mold (10) for sandwich rolls having an interior sandwich component cavity, includes a retaining member (11) and a form member (12). The retaining member (11) is a generally hollow cylinder having a circumferential side wall (15). The form member (12) includes a cylindrical slug (18), a spacer rail (19) and a support portion (20). The support portion (20) includes a U-shaped handle (30) and a semi-cylindrical support strap (31). The form member (12) is fitted into the retaining member (11) such that the spacer rail (19) engages the interior of the circumferential side wall (15) and the semi-cylindrical support strap (31) engages the exterior of the circumferential side wall (15) so as to positively position the form member (12) in a fixed spatial relationship within the retaining member (11). The retaining member (11) is partially filled with dough which is allowed to rise prior to assembly. Thus, the mold (10) serves to produce a sandwich roll having an enclosed cylindrical sandwich component cavity.

Abstract: Apparatus and method for constructing a manhole collar between an existing manhole cone and a precast manhole ring. The apparatus includes a circular slip form tube, tapered from a larger top diameter to a smaller bottom diameter; at least two support arms, radially extending from adjacent the top of the slip form tube for placement on a support surface, such as a road surface, to hold the tube at a selected height relative to ground level within a manhole cone; and a plurality of fasteners for attachment of a precast manhole ring about the exterior periphery of the slip form tube for supporting the ring at a selected height relative to the manhole cone and the roadway surface. The apparatus may include a concrete spill retention ring, placeable upon the top rim of the manhole cone and around the slip form tube to prevent concrete from entering the manhole cone.

Abstract: A mold for forming an open top, walled member having side walls and a bottom surface for containing a molten metal. The mold including an inner screen having a plurality of openings having inner side walls and a bottom surface. The mold further includes an outer wall, wherein the inner screen and the outer wall are spaced relative to each other to define a space so that the side walls and the bottom surface of the open top, walled member are formed therebetween.

Abstract: A pocket former having a body with a tapered exterior surface. The body has a top surface and a bottom surface and a tubular member extending therethrough. The top surface extends outwardly from the tubular member for a greater distance than the bottom surface. The top surface and the bottom surface define a pocket therebetween. The top surface tapers to the bottom surface. The pocket has a generally semi-circular configuration at one end with a top surface forming a linear edge of the semi-circular configuration. The pocket has another portion of generally circular configuration. A plurality of radial struts extend from the tubular member to the top and bottom surfaces.

Abstract: A compressible band and end retainer assembly which secures opposite ends of a band to an intermediate spacer. The band mounts between facing concrete sidewall forms to define a hole, upon pouring and curing a slurry of surrounding concrete. Various band geometries permit hole formation in planar or curvilinear poured walls.

Abstract: The mold is comprised of a bottom (4) wherein there are provided grooves (8) extending transversely between containment sidewalls (6); said sidewalls (6) have windows (14) which are aligned with the grooves (8) which preferably are delimited by the faces (10) of fillets (12) arranged in parallel, facing each other and fixed to the bottom (4) of the mold.

Abstract: A reusable concrete spacer sleeve comprises a substantially cylindrical body having a plurality of inwardly extending fins. The sleeve is placed over a vertical drain pipe prior to pouring a concrete floor. After the concrete has set, the sleeve is removed, leaving an annular space around the pipe for accommodating a flange. A lid may be fitted onto the sleeve to prevent debris or other foreign matter from entering the pipe or the annular space around the pipe.

Abstract: The said structure presents a constitution which, as well as providing a great resistance, supposes an effective reduction of the depth of floor slabs and technical layers built with current construction systems while allowing the incorporation of various technical elements and installations.

Abstract: A method of forming an extrusion die fabricated from sinterable ceramic or metal powders, for use in forming honeycomb monolith structures including machining of the die in the green state or after partial densification. Alternatively, all or part of the machining can be performed after full densification or sintering.

Abstract: A ramp for the physically challenged includes three different types of sectional portions: a slab disposed at the interface of a level surface such as a floor or earth ground; one or more ramp portions, each having a sloping upper surface, disposed adjacent to one another; and a switch platform having a level upper surface. Forms used to fabricate the three different types of sections are provided. A form for fabricating the sloping ramp portion includes a bulkhead, outer panels, and a set of inserts having varying height. The inserts are used to vary the resulting depth of the side panels of the concrete ramp portions. An upper surface of the bulkhead is sloped downwardly in a plane parallel to that of the upper surface of the concrete ramp portion. Apparatus is provided to elevate the front portion of the assembled form so as to place the upper surface of the bulkhead in a horizontal plane that is parallel to the plane of the level surface upon which the form rests.

Abstract: A molded strap channel and method are disclosed for a kayak and the like or article molded from a flexible skin using a rotational molding process. The strap channel includes a continuous channel having an arcuate shape and a continuous taper from a first channel opening to a second channel opening. First and second channel openings open in a common surface of the flexible skin of the hull and lie generally in a common plane. In accordance with the method, a rotational molding process is disclosed wherein plastic material in a split mold is subjected to a rotational molding process which forms a thin, plastic hull and a continuous strap channel molded about a forming member attached to one-half of the mold. The forming member is unattached from the mold, and the hull is removed from the mold whereby the forming member is tapped and removed from the strap channel so that a continuous strap channel is molded as one-piece with the hull having first and second channel openings as described above.

Abstract: An open and shut molding method of making a paint roller bearing with offsetting core support surface for use in paint roller applicators that permit the user to change a paint roller quickly and efficiently on a paint roller applicator by bringing together a first mold and a second mold until a portion of the molds contact each other to thereby provide central regions in the mold cavity to exclude moldable material therefrom and then flowing a moldable plastic material into the mold cavity formed between the first mold and the second mold and separating the first mold from the second mold to enable removable of a ready to use molded one piece paint roller bearing housing having a central opening extending therethrough for inserting of a shaft therein for rotatable supporting the ready to use paint roller bearing housing thereon.

Abstract: Concrete blocks are formed in a mold having a cavity into which block-forming material is placed. A portion of the material is retained in place relative to the cavity walls when the block is removed from the cavity, and the face of the block forming material adjacent a surface of the material retained in place is provided with a split-type appearance to its surface. A block having a rough surface closely resembling a split surface can thus be attained without the expense and time involved in conventional block splitting. The assembly can be constructed to form blocks having non-planar split-type surfaces. Additionally, split-type surfaces can be formed on an interior surface of a composite block module adapted for splitting along a splitting plane, to attain a block providing a split-type appearance along two spaced planes.

Abstract: A wax pattern molding process, employing a mold having a cavity and a core structure in the mold cavity that include closing the mold with the core structure positioned in the mold cavity; injecting flowing heated wax into the mold to flow about the core; allowing the injected wax to cool and solidify to form the wax pattern; removing the core structure from the solidified wax pattern, while the mold holds the pattern in position in the mold; and opening the mold and removing the unencumbered wax pattern from the mold.

Abstract: A method and apparatus for constructing an above ground concrete encased storage tank. The apparatus has a support assembly that extends from the baseplate of a concrete form, that supports, elevates, and secures an inner storage tank from the form baseplate, so that the tank may be completely surrounded by concrete. The form has removable walls that may be pivotally attached to the baseplate and initially in a horizontal position. The support assembly has anchor bolts that extend through holes in the baseplate. The anchor bolts are screwed into anchor nuts that are attached to a pair of brackets. The anchor nuts and brackets are spaced from the baseplate by sleeves that fit over the threaded portions of the anchor bolts. The brackets are constructed to support the storage tank, which is placed in the form on top of the support assembly. The tank is then fastened to the support assembly.

Abstract: A unitary helical coil spring assembly is inserted in a tubular body to form a neon tube support. The assembly is molded of plastic using a mold comprised of two planar blocks in each of which there are a series of axially spaced apart recesses configured to form half convolutions of a spring and there are projections having rounded ends projecting from between half convolution recesses on each mold block which interdigitate and project into the half convolution recesses in the opposite mold block when the planar surfaces are interfaced so the rounded ends cooperate to form a circular inside diameter of the spring when plastic is injected in the recesses.

Abstract: A mold for skin covered foamed plastic molding which utilizes a middle mold to be placed between an upper mold and a lower mold, capable of reducing the weight of the middle mold so that assembling of the middle mold becomes less troublesome, the assemblage becomes more stable and the appearance of undesirable spacing in the assemblage an be prevented. The mold includes an upper mold to be closed over the lower mold, having a bent portion with a bottom surface which is to be a part of molding surface; and a middle mold to be placed between the upper mold and the lower mold, having a hollow region into which the bent portion of the upper mold is to be engaged when assembled.

Abstract: This invention relates to a mold for making a formed chair arm with passages therein.

Abstract: A molding device for molding a sliding member of a slide fastener includes a first mold, a second mold movable toward or away from the first mold to close or open the molding device, at least one set of upper movable moving parts, a first upper stationary molding part detachably fixed to the first mold and a second upper stationary molding part detachably fixed to the second mold. The upper stationary molding parts are replaceable to alter the design of the holding end of a pulling tab of the slide fastener. Each set of the upper movable molding parts includes a first and a second upper movable molding part installed in the first mold, a third and a fourth upper movable molding part in the second mold.

Abstract: A method for testing foam formulations for the quantitative measure of the effects of formulation and/or process variable changes on some kinds of surface problems of a molded part caused by different degrees of imperfection or voiding underneath the part surface. The molded part can be single component or composite, solid or foamed. One example of the surface problem is the so-called "measles or cellulite" problem observed on the vinyl surface of a vinyl/foam composite due to the voids or rattiness within the foam. To accomplish this result, the mold has various sized, spaced apart, aligned openings formed in each of the front and rear walls of the mold, but with the centers thereof at different elevations in the respective front and rear walls. Removable rods inserted through the aligned mold wall openings produce longitudinal openings through the part which is molded around the rods, permitting the effect thereof on the surface of the molded part to be evaluated.

Abstract: A method of making a slider for use in a slide fastener, which slider is provided with bearings for a pull tab on an upper surface of a slider body on its opposite side to pivotably hold a pintle of the pull tab. By making use of only one slide core, a slider body mold cavity in a mold is blocked from a pull tab mold cavity and at the same time, hollow space portions in the bearings for the pull tab are formed by means of the slide core. After molding the slider body, by retreating this slide core, the hollow space portions in the already molded pull tab bearings are used as a mold portion for a pintle of the pull tab. By injecting an amount of molten synthetic resin having a larger thermal contraction coefficient than the synthetic resin used previously for molding the slider body, into the pull tab mold cavity, the pintle of the pull tab and the pull tab are integrally molded.

Abstract: A mold for injection molding including a cylindrical outer mold and a columnar inner mold. The inner mold is provided, on its external circumferential surface, with a large number of tooth-shaped grooves extending in the axial direction thereof, and it is placed inside the outer mold to define an annular cavity between the external circumferential surface of the inner mold and the internal circumferential surface of the outer mold. The outer mold is provided with a plurality of runners extending axially near the internal circumferential surface. The runners are arranged at regular annular intervals along the circumference of the outer mold. Furthermore, slit-shaped gates are formed along the full length of the runners, the gates opening into the internal circumferential surface of the outer mold, in such a way that the inflow of molten molding material flowing from each runner into the cavity is gradually reduced along the runner from the upstream side towards the downstream end.

Abstract: This invention relates to an apparatus for molding slotted concrete floor sections. The apparatus forms the concrete floor sections in an inverted position so as to avoid the need for hand finishing of the upper surface of the molded concrete floor sections. The apparatus comprises a base, opposing pairs of interconnected upstanding side and end walls connected to the base and a plurality of elongate spaced apart and substantially parallel ridges connected to and projecting upwardly from the base. Attached to and overlying the ridges are a plurality of elongate keystone shaped dividers removably mounted on and extending upwardly from the ridges with the upper surface being in a substantially common plane with the upper surfaces of the side and end walls.

Abstract: A method of moulding racquets to define stringing holes in the moulded frame. The method includes forming at least one approximately ladder-shaped member having two side pieces interconnected by rung pieces, with the side pieces substantially conforming to the curved shape of at least part of the frame of the racquet; entrapping the ladder-shaped member between two mould plates defining a mould cavity; injecting a plastic material into the mould cavity to mould the frame around the rung pieces; and forming the ladder-shaped member in two parts and separating the two parts after the frame has been moulded to remove the ladder-shaped member from the moulded frame.

Abstract: A die assembly for die casting a propeller structure, such as a wax propeller pattern. The pattern, which is identical in configuration to a cast metal propeller to be produced, includes a generally cylindrical hub having an outwardly flared end and a plurality of blades project outwardly from the hub. The die assembly includes a base plate and a lower core section extends upwardly from the base plate through an opening in a stripper plate, which is mounted for movement toward and away from the base plate. A plurality of die sections are mounted for generally radial sliding movement on the stripper plate from an outer open position to a closed position where they define a die cavity with the core section. The die assembly also includes an upper die unit that is mounted for vertical movement and has a cavity in its lower surface which receives the upper ends of the die sections when in the closed position.