Abstract: A method and an apparatus are disclosed for vacuum or gauge pressure shaping of extensible sheet material in a mold, more particularly pre-shaping of a textile or plastic sheet or film used as an integral skin for a foam cushion, to effect uniform stretch of the sheet throughout its area notwithstanding substantial depth variation in surface contour of the final shaped sheet material.

Abstract: A method and apparatus for making biological discs comprises the steps and means for welding the longitudinal edges of a pair of identical rectangular plastic sheets together to form a single large sheet. This single large sheet is conveyed to a heating and vacuum forming station where the sheet is heated and vacuum formed to have a plurality of convex cup-like projections formed in the surface thereof. The sheet is then moved to a cutting station where heating mechanisms form openings therein for accommodating an axle and a plurality of tie rods, and the sheet is cut in circular configuration by a cutting device shiftable on a radius of predetermined magnitude.

Abstract: A mold for vacuum forming plastic sheet and the like and a method of making the mold. A relatively thin mold shell provides a forming surface through which small apertures open to exhaust air to vacuum form a heat-softened plastic sheet. Small manifold conduits behind the forming surface connect the apertures to a source of vacuum. The mold area subtended by the manifold conduits is substantially less than the area of the entire forming surface, thereby substantially limiting the force exerted upon the forming surface by the pressure differential created during vacuum forming of a plastic sheet. The mold is preferably made by electroforming a metallic shell on a pattern, and is apertured in a desired pattern. Filaments are advantageously used to form the apertures during electroforming. A low melting point material is applied to the back of the shell in a manifold pattern to connect the apertures and a metallic layer is electroformed to the back of the shell.

Abstract: A centrifugal casting machine includes a rotatable shaft having a mounting plate for receiving a pair of molds containing the casting cavities. A passage in the shaft has one end connected to a source of vacuum and the other end opening in the plate. A conduit is provided from the casting cavities to the exterior of the molds. Connection means are provided for applying the vacuum in the passage to the cavity through the conduit. The vacuum so applied improves both the operation of the casting machine and the quality of the castings.

Abstract: Fiber reinforced plastic structural components having curved surface areas are produced in molds utilizing a bleeder cloth comprising a textile-like non-woven polyester fabric characterized by a fiber interlock value of at least 7 and a fiber entanglement completeness of at least 0.5. The utilization of this bleeder cloth allows quicker assembly of the mold components since cutting and forming are not necessary, proper pressure transmittal is ensured, and the air permeability, drape, stretchability, and resin holding capacity of the cloth are ideal. For producing the desired structural components with curved surface areas, at least one layer of resin pre-impregnated partially cured fabric is disposed in cooperation with a first mold section, a release liner is placed on the fabric, and a bleeder cloth according to the invention is placed on the release liner.

Abstract: Hydraulic cement or the like is poured into a closed mould under a reduced pressure condition to a level slightly higher than a predetermined level. Coarse aggregate and steel rods are prepacked in the mould. After pouring, the pressure in the mould is increased to atmospheric pressure or a higher pressure to force the hydraulic cement above the predetermined level back into the space below the level thus compacting the poured in hydraulic cement. A cushion device is provided for the pouring device. An overflow tank is connected to the mould to observe the level of the poured cement. The pressure in the overflow tank is also decreased during pouring and increased after pouring.

Abstract: A method of removing an article from a chamber having a reduced pressure therein by connecting the chamber to a pool of liquid by a barometric leg is disclosed. The method provides a conveyor in said barometric leg and allows said article to float up into engagement with said conveyor so that the force exerted on the article by the conveyor moves the article down into the pool of liquid and out into the atmosphere.

Abstract: In an injection moulding process for forming hollow preforms on a mandrel which is subsequently used as a blowing pin for blowing the preforms to the final shape in a blow mould separation of the preform from the mandrel during cooling of the preform from the injection temperature is prevented by applying a vacuum to the blowing channel in the mandrel before the injection pressure is released.

Abstract: A gas-permeable seamless pipe structure formed in a pipe shape by a wet process comprising (A) 20 to 95% by weight of thermoplastic fibers and (B) 5 to 80% by weight of a component consisting of (a) 20 to 100% of other fibers being infusible at the fusing temperature of said thermoplastic fibers (A) or having a higher melting point than said thermoplastic fibers (A) and (b) 0 to 80% by weight of a void-containing particulate material having an apparent density of not more than 1 and an average particle size of 20 to 2,000 microns and being infusible at the fusing temperature of said thermoplastic fibers (A), said thermoplastic fibers (A) being bonded to the other component (B) as a result of heat fusing; a method for producing the pipe structure; and an apparatus for use in this method. The pipe structure has superior physical properties such as strength and hardness, good water resistance, light weight and superior gas-permeability.

Abstract: A press and vacuum box combination for manufacturing articles from fluent, curable or hardenable material within a vacuum atmosphere, especially designed to provide access to the mold parts, optimum article handling and improved safety. The press has side frame members, a cross head lying in a horizontal plane and extending between the side frame members, an axially reciprocable ram movable between raised and lowered positions, a platen associated with the cross head and a platen associated with the ram. A mold part is associated with each of said platens, and the mold parts are arranged for movement between opened and closed positions. In the closed position, the mold parts define at least one cavity having the shape of an article to be molded in the press. One of the platens has means at one edge thereof for hingedly mounting the platen for movement between raised and lowered positions with respect to the cross head. Means are associated with the cross head for supporting the hinged mounting means.

Abstract: Means for vacuum forming a plastic film to form a continuous liner about the interior of a drum, using the drum shell as a mold member.

Abstract: A method and apparatus for vacuum embossing sheet thermoplastic material which utilizes an endless, seamless structure as the embossing surface. A sheet of heat-softened thermoplastic film is passed over an embossing screen, the embossing screen being supported by two support rolls, a drive roll and two seal rolls. A vacuum is applied to the screen between the seal rolls to pull the film into contact with the screen thereby producing an embossed pattern on the film corresponding to the outer surface of the screen. After the film is removed from the endless, seamless screen the film is cooled to set the pattern in the film. The process produces an embossed film which has high strength, low surface gloss or light reflectance, and a deep embossed pattern.