Abstract: An improved vacuum forming process for forming a deep drawn plastic article with a flange in an area of high forming stresses wherein a mold mounted on a base forms the shape of the article. A sheet of hot plastic material is placed over the mold and a vacuum is drawn to form the plastic sheet into the shape of the mold to form the article. The improvement is forming a character in the mold portion that forms the flange in the area of the high forming stress, said character having dimensions such that properly heated plastic sheet material will be imprinted with a predetermined clarity during the molding operation. A heated sheet of plastic material is placed over the mold and a vacuum is drawn to draw the plastic material around the mold including the mold portion that forms the flange in an area of high forming stresses. The plastic material is then solidified and removed from the mold. The flange is visually inspected to determine if the imprinted character has the predetermined clarity.

Abstract: Concrete elements, such as blocks or bricks, are molded or cast by forming in a primary mold cavity a secondary mold made of a portion of a thermoplastic film which has been contacted with a flat heater surface to assure a uniformly heated film portion which is then sucked into the primary mold cavity without wrinkles and filled with concrete mix. The secondary mold with the concrete mix in it is withdrawn, for example, sucked out of the primary mold cavity well before any effective hardening of the concrete mix, so that curing and hardening takes place in the secondary mold outside the primary mold cavity. This early withdrawing is important because it avoids expansion of the curing mix in the primary mold, whereby removal from the primary mold is facilitated. Additionally, the early removal with the aid of the secondary mold assures a more efficient use of the primary molds which are used again while the hardening is still going on in the secondary mold.

Abstract: Poly(ethylene terephthalate) compositions containing a small amount of a terpolymer of ethylene containing carboxyl groups, which may be partly or completely converted to a divalent metal salt form, and reinforced with a mineral material having an aspect ratio of at least 10 can be formed into sheets which are readily thermoformable at moderate pressures and have very good thermoforming radius ratios.

Abstract: The present invention concerns a process for a thin sheet molding of a thermoplastic resin easily and economically and also the thin oriented sheet molding prepared by such a process. Its specific feature resides in the steps of lubricating the inner surface of die, laying over one another thermoplastic resin blanks while being not adhered to each other in a die, compressing the layered structure at a temperature higher than the glass transition temperature of the thermoplastic resin blanks and separating the oriented molded products from each other.

Abstract: Thermoforming machines with a heating station and a downstream mold station have carrier clamp frames for gripping the edges of sheets of plastic at a load station and indexing them successively to a heating station and a mold station. The carrier frame members to which the plastic may be releasably clamped carry their own remotely operated clamps and are themselves expandable and contractible to a condition in which, prior to molding, they control the sag in the sheet formed during heating of the sheets to differential pressure forming temperature. The plastic sheet can be molded to only a portion of a product which functions as a mold member.

Abstract: Cupola-shaped plastic pieces with a flat, unwarped rim can be produced from an equally large blank without trimming of the rim, by heating an optionally preheated plastic sheet by radiant heat. The radiant heat acts only on the area surrounded by the rim area until the area exposed to the radiant heat has reached a temperature just below the softening temperature of the plastic. Up to this point, the rim is left without tension, or at most a low clamping pressure is applied which allows a thermal movement of the rim. Then, but before the beginning of the forming, the clamping pressure is increased so that the rim is held tight. The radiation activity continues until the area exposed to the radiant heat has exceeded the softening temperature, the radiation activity is then stopped, and the area heated to the forming temperature is formed.

Abstract: An improved method of forming a decorative panel of molded plastic comprising the steps of constructing a form having a detailed masonry surface; covering the detailed surface with a mold release material; applying a thin layer of gel coat over the mold release; applying a plurality of layers of fiberglass matte and resin over the gel coat layer; allowing the plurality of fiberglass matte and resin layers to harden thereby forming a heat resistant mold having a female side being formed against the detailed surface and a side opposite from the female side; removing the mold from the form; perforating the mold thereby providing fluid communication between the two sides; connecting a vacuum apparatus to the side opposite of the mold; placing a sheet of high impact plastic above and adjacent the female side of the mold; activating a heater thereby heating the plastic sheet to a pliable state; activating the vacuum apparatus thereby drawing the plastic sheet into the female side of the mold; and removing the forme

Abstract: A system for producing generally concavo-convex synthetic plastic containers and like articles, such as picnic plates wherein a mold station has a stationary intermediate mold with projecting male mold parts on one side and directly opposite recessed female mold cavities in alignment therewith on the other side. A first movable mold, on the side of the intermediate mold having the male mold parts is provided with recessed mating female mold cavities of the same dimensions as the said cavities in the intermediate mold and a second movable mold on the other side of the intermediate mold has aligned projecting male mold parts mating with the cavities in the intermediate mold. A pair of heated, moldable synthetic plastic webs are advanced in unison to opposite sides of the intermediate mold and are later removed in unison from the mold station. The heated sections of the webs are moved in unison to opposite sides of the intermediate mold when the said first and second movable molds are separated therefrom.

Abstract: Disclosed is a process of making an oriented and heat set thermoformed hollow article of poly(ethylene terephthalate) so that the sidewalls of the articles resulting from the process have a density over 1.391 cc./gm. and an onset-of-shrinkage temperature over 105.degree. C. In the process, a sheet preheated to a temperature suitable for orientation is biaxially stretch thermoformed and then while the hollow article walls are still in contact with the mold walls, the article is raised to a higher heat setting temperature in the range of about 220-250.degree. C. thus heat setting the article, and while the article is still under restraint resisting shrinkage, quenching the sidewalls of the article to a temperature that will provide a shrinkage of less than about 5% by volume and the above onset-of-shrinkage temperature of at least about 105.degree. C.

Abstract: A rigid snap-on plastic cover for a sun-damaged vinyl-covered dashboard pad is installed in an automobile without loosening or removing the dashboard pad from a dashboard substructure. The snap-on cover is made by draping a preheated softened polycarbonate sheet over a mold positioned on a narrowed support. A partial vacuum is produced in the region covered by the draped polycarbonate material, causing it to be drawn against the mold for support and to conform thereto. A skirt portion of the polycarbonate material from the support is severed after the vacuum is released, and the forward portion of the hardened polycarbonate is lifted over the mold, forcing any breakage of the "back draft" portion of the polycarbonate to occur in forward corner locations that will not be visable when the snap-on cover is installed in the automobile. The peripheral portions of the polycarbonate material are cut cleanly away and the outer surface is spray painted.

Abstract: The present invention relates to the simultaneous shaping and lamination of lightweight laminated transparencies, particularly those that are suitable for use in aircraft. The plies of an assembly to be shaped and laminated are assembled with additional elements to form a flexible cell of air impervious material. The cell includes an air impervious flexible wall defining a peripheral space around the assembly and porous material in the space. The cell containing the assembly is mounted over a vacuum mold and heated to sag the cell and its assembly to the contour of the mold while evacuating the cell while the cell and said assembly are exposed to atmospheric pressure.The cell is cooled while still under evacuation until the shape of the assembly is set, then is separated from the vacuum mold. The resulting assembly thus shaped and laminated is separated from the cell.

Abstract: A unitary, thermoformed container having an undercut or re-entrant seal flange is provided. The container is made in a molding method and apparatus in which a flange-forming portion thereof has a short-stroke gate assembly that opens after the unitary, thermoformed container has been formed in order to provide an exit path away from the molding cavity to permit ready removal of the thermoformed container out of the molding cavity and its flange-forming portion.

Abstract: A process and apparatus for stacking layers of composite material on moulding equipment comprises a transfer band on which each of two opposed working sections has a surface suction device to hold on it a layer that has been placed in a precise position in register with an outline, projected onto the transfer band by means of neon tubes and a frosted glass plate in a first working station. The band transfers the layer to a second working station where the layer is isolated in a sealed enclosure by means of an inflatable joint carried by a frame facing a peripheral ridge surrounding the moulding equipment. Reduced pressure is produced in the enclosure via a reduced pressure outlet causing the transfer band to be displaced towards the moulding equipment and draping the layer over the latter.

Abstract: Apparatus for manufacturing articles is disclosed in which a preheated sheet of thermoplastic material is intermittently fed to present successive preheated portions of the sheet in a work station having a forming tool for forming articles in each successive sheet portion and a stamping tool for co-operating with the forming tool to stamp the formed articles from the sheet. The forming tool has a plurality of forming dies which are movable successively and cyclically into the work station for forming articles in respective successive sheet portions. After each forming operation the stamping tool is brought into engagement with a resilient counter-surface on the forming die to stamp from the sheet the articles formed by that die.

Abstract: An artificial heart valve having thin, seamless leaflets which converge to the center of a frame from the frame's inner wall. The leaflets each have a convex outflow surface and a concave inflow surface. The leaflets meet along adjacent edges to form cusps. Sinus valsalvae sections of the valve are formed as rounded recesses defined in the valve frame's inner wall as continuous curved profiles of the respective leaflet concave surfaces. The valve is fabricated by vacuum molding techniques whereby layers of elastomer are vacuum formed to comprise the leaflet and sinus valsalvae portions. In one embodiment, the leaflets are all formed from two or more layers of elastomer which are cut to define the leaflet edges or commissures. One elastomer layer extends along the frame recess to provide continuity for each leaflet and its sinus valsalvae. The resulting structure has no rims or seams in the inflow or outflow paths.

Abstract: A shaped article such as a container of polyalkylene terephthalate resin is described. The shaped article includes a body portion in which the resin has an average crystallinity of at least about 20 percent. The shaped article is provided with the flange which adjoins the body portion of the article. At least part of the flange has an average crystallinity less than that of the body portion and preferably of not more than about 10 percent. Process and apparatus which may be employed in the manufacture of such an article are also described.

Abstract: A differential pressure forming machine with upper and lower mold members for forming cup-like articles in a web of thermoplastic material includes a mold assembly in which two separable die members, when in their closed position cooperatively form an article defining mold cavity which extends through one member and into the other. The two die members, when opened, are spaced from each other by a distance greater than the depth of the formed article. An endless chain of carrier members is located with one run extending between the two die members. Each carrier member has an opening smaller than the circumference of the formed article. Closing of the die members expands the carrier member opening outwardly of the periphery of the die cavity and closing of the entire mold assembly in the forming operation effects a severing of the formed article from the web.

Abstract: Reinforced poly(ethylene terephthalate) sheets are thermoformed to articles having one or more surfaces in contact with the mold of such a degree of smoothness that they virtually completely replicate the mold face. When the mold face is completely smooth, the concave imperfections caused by air entrapment in the plastic material account for less than 6% of the surface area. Composite articles consisting of a face member and a backing member are made by thermoforming in a single mold a face member having one or more surfaces in contact with the mold face of such a degree of smoothness that it completely replicates the mold face, and its proportion of concave imperfections is less than about 6% of the surface area. The backing member is bonded in the mold with an adhesive to the face member, and the composite structure is allowed to remain in the mold for a sufficient time to permit subsequent removal without distortion.

Abstract: This relates to the forming of containers and like hollow articles from sheets or webs of thermoplastic material. Two webs or sheets are simultaneously acted upon by way of a forming apparatus which includes a reciprocating clamp first cooperable with one outer platen and then the other in sequence wherein, while a first web or sheet is being formed within a plurality of mold cavities to define a plurality of hollow articles such as containers, the other sheet or web may be stripped from its respective mold set and a new sheet or a new portion of a sheet or web may be advanced into position for molding. The forming apparatus may be constructed in a manner wherein the web portions which are to be formed may be billowed away from the mold cavities as an initial step in the stretching and orientation of the thermoplastic material.

Abstract: A film packaging machine 20 has a vacuum platen 28 with a slidable air-permeable discharge plate 72 that is driven by air cylinders 112, 114 within the platen to eject a finished package by moving a leading edge of the package off the platen and into pinch rolls 62. A small plenum 96 beneath the platen surface at the discharge end, extending across the width of the platen, is supplied with air under pressure to relieve the vacuum beneath the leading portion of the package to facilitate ejection.

Abstract: A method of manufacturing a raised relief, illuminated globe includes printing a hemispherical map design on a flat vinyl plastic sheet, forming the vinyl plastic sheet into a substantially hemispherical shape, positioning the hemispherically formed sheet in a mold cavity, positioning a mold core on the back side of the sheet, injection molding a styrene backing for the hemispherical shaped sheet to conform the sheet with the mold cavity including relief areas defined in the cavity wall, and removing the molded hemisphere from the mold. A second molded hemisphere is produced in substantially the same manner and is attached to the first hemisphere to form a complete globe. The printed map design of the globe is positioned in the mold cavity to insure that the relief areas are properly positioned with respect to the design.

Abstract: A molding mixture comprising a filler, such as wood particles and a resin binder, is pressed under light pressure on a flat bed to produce a mat with a density between 1/15 and 1/3 of the material in the finished article to be made by pressure molding. A molding preform is then made from a piece of such mat having a suitable contour, by sculpturing one side of the mat with suction devices to provide a thickness variation over the mat area corresponding to the requirements of the molding step.

Abstract: A method of forming plastic sheet material into articles. The sheet is heated and is formed into the article in a mould. The mould parts severe the portion of the sheet which is to be formed into the article and at the peripheral edge of the said portion the mould parts squeeze the plastics material to cause it to flow outwardly into a bead cavity in which the material forms into a thickened bead.

Abstract: A method of duplicating shapes embodying resinous material and more particularly fiber reinforced resinous material is taught. The method includes the formation of a mold separation sheet conforming to the mold contours, placing the separation sheet within the mold and charging the mold with the desired resinous mixture. Upon curing of the resinous mixture and ejection of the article from the mold the separation sheet is removed and discarded.

Abstract: A shaped article such as a container of polyalkylene terephthalate resin is described. The shaped article includes a body portion in which the resin has an average crystallinity of at least about 20 percent. The shaped article is provided with the flange which adjoins the body portion of the article. At least part of the flange has an average crystallinity less than that of the body portion and preferably of not more than about 10 percent. Process and apparatus which may be employed in the manufacture of such an article are also described.

Abstract: The present invention relates to an improvement in a method for thermoforming of containers from thermoplastic materials in which method the rim of the container is formed as an integral part of the pre-form from which the container is thermoformed. The pre-form is obtained by introducing thermoplastic material into a closed space and then mechanically compressing the material. The improvement of the present invention relates to improved uniformity of flow of the thermoplastic material into the closed space, the use of a closed space defined by surfaces having a surface roughness in the range of 50-125 .mu.m rms and to a modified sequence of steps for forming the pre-form in which the compression of the thermoplastic material is commenced prior to the completion of the introduction of the material into the closed space. The process may be used in the manufacture of containers, e.g., for the packaging of margarine, from polyethylene or polypropylene.

Abstract: A method for molding a polycarbonate plastic sheet into a skylight dome or the like. A clamp frame is preheated to a first temperature. A polycarbonate plastic sheet is thereafter clamped around its perimeter in the preheated clamp frame and preheated to approximately the first temperature. The unclamped portion of the plastic sheet is heated to about 300.degree. by ovens to soften the plastic for forming. The softened plastic sheet is then subjected to forming by a pair of coacting peripheral heated molds to form steps and pushes in the plastic sheet immediately adjacent to the clamp frames. A vacuum is drawn over the center portion of the sheet to free-form a dome. The molds are separated and the formed article is removed from the heated clamp frame. The steps of preheating the plastic sheet perimeter in the heated clamp frame and heating of the peripheral molds prevents distortion of the flange area of the slylight dome and of the step and push areas of the dome.

Abstract: A finished concrete part is prepared in a casting mold with a perforated mold wall. A pliable thermoplastic film is placed over the inner surface of the casting mold wall, the film is heated sufficiently to make is supple enough to conform to the inner mold wall surface, the supple film is sucked against the inner mold wall surface under vacuum, the lined mold is filled with concrete, the concrete is permitted to harden in the lined mold while being vibrated to compact the concrete in the mold during hardening, and the hardened finished concrete part is removed from the mold.

Abstract: One disadvantage of a biaxially stretched, blow molded bottle of a saturated polyester resin, particularly polyethylene terephthalate, presenting many excellent features and physical properties, lies in its neck portion which is not subjected to stretching during the molding of the bottle, but which is inferior to its body portion in such physical properties and features. This disadvantage is eliminated by molding at least the neck portion of a parison for such a bottle from a biaxially stretched plate of the resinous material from which the bottle is molded, so that both the neck and body portions of the bottle are composed of the duly biaxially stretched material.

Abstract: A shaped acrylic glass body is provided which has a reshaped inner zone outside the plane of the border or edge region and which is characterized by excellent resistance to weather and to chemical corrosion. The shaped body is manufactured from an extruded plate of a polymer or copolymer containing at least 80% by weight of polymethylmethacrylate or a copolymer of methyl methacrylate. The extruded plate is subjected to biaxial stretching, by at least about 25% in each direction and, while the edges or border regions are gripped to maintain their dimensions, a force is applied to the interior portion of the plate while it is in a thermoelastic state to move the interior portion out of the plane of the surrounding edges.

Abstract: Process for the low temperature shaping processing of polyethylene terephthalate which comprises preparing a polyethylene terephthalate shaping material having the predetermined shape by subjecting polyethylene terephthalate having an average molecular weight of at least 12000 to an extrusion moulding or injection moulding operation and, optionally, laminating a high polymer material, or metallic or inorganic material on the shaping material, pressing the shaping material or the laminate shaping material against a mould having the predetermined shape at a temperature of 0.degree. to 240.degree. C. under the conditions comprising a total processing pressure of 5 to 800000 kg, a unit pressure of 3 to 30000 kg/cm.sup.2 and a processing rate of 2 to 10000 cm/min.According to the above described process, a shaped article having toughness and uniform quality can be easily and cheaply obtained.

Abstract: The specification discloses an apparatus and method for molding glass fiber reinforced polyester resin articles. A bladder-covered male mold is in turn covered with resin and reinforcement and a female mold with a surface forming film located therein or with a smooth surface is then closed over the male mold. With the bladder held against the male mold by vacuum, air is evacuated from between the bladder and the female mold. The vacuum between the bladder and the male mold is then released whereby the bladder is forced against the resin to thereby force it against the film which is located within the female mold or against the mold surface. This insures a molded article with a bubble free surface. Where a film is used, this insures a tight air free bond between the resin and the film.

Abstract: A forming die including a cup-shaped cavity for the vacuum thermoforming of sheets of thermoplastic material includes, in the center of its bottom, an upwardly directed pointed projection, the height of which is remarkably smaller than the depth of the said cavity. The suction bores through which vacuum is generated at the interior of the cavity are arranged at the periphery of the bottom of the cavity itself.

Abstract: A surfboard having a central core of relatively soft and/or light material such as balsa wood or foamed plastic and a laminated outer skin construction is disclosed herein along with a method and apparatus for making the surfboard or a similar article. Both the method and apparatus utilize particular vacuum molding techniques which form the laminated outer skin constructions while at the same time accurately conforming this skin construction to the complex curvatures of the core.

Abstract: A vacuum formed water bed mattress providing a pair of large flat opposite parallel sides and four narrower sides joined to form a substantially right regular parallelopiped is disclosed. One of the large flat sides is made of a heat resistant material. The other flat side and four narrower sides are formed from a single sheet of material by a vacuum and temperature molding process. The two sheets are heat sealed to form the mattress. A method for the making of a water bed mattress is also disclosed.

Abstract: A sheet formed from a uniform blend of from about 80 to 97% by weight of polyethylene terephthalate having an intrinsic viscosity of above about 0.9 and a melt viscosity at 525.degree. F. of above about 10,000 poises and correspondingly from about 20 to 3% by weight of a polycarbonate resin having an intrinsic viscosity of about 0.4 to 0.6 and a melt viscosity at 500.degree. F. of less than 50,000 poises; said sheet having a haze value as determined by ASTM D-1003 of less than about 2% and being essentially amorphous and non-oriented. Also disclosed is a process for forming a sheet which comprises uniformly blending the composition, extruding the composition into a sheet at a temperature between about 490.degree. to 530.degree. F. and rapidly cooling the sheet by contact with at least one cooling surface maintained at a surface temperature in the range of about 50.degree. to 160.degree. F. for a period of time not exceeding about 15 seconds.

Abstract: A method and apparatus for thermoforming articles from plastic sheet material and for forming holes in the thermoformed articles in a single operation involves heating the material and vacuum drawing the heated material into a mold cavity which has an aperture corresponding in shape to the desired hole. The underside of the mold cavity is tapered outwardly away from the aperture, and, as the sheet material is drawn into the cavity, it follows the taper, is thinned, and is trapped in the cavity. The hole in the article is created when the sheet material not drawn into the cavity is stripped from the mold.

Abstract: This invention pertains to a method for thermoforming thin-walled plastics articles from an elongated polyolefin web which is manufactured so as to have minimum orientation so that it will expand lengthwise and widthwise when passed through a heating zone prior to thermoforming, which method comprises moving the web both laterally and longitudinally in a co-ordinated manner whereby the normal inclination of the web to sag because of the longitudinal and lateral expansion of the web due to heating is effectively eliminated.

Abstract: A double wall plastic article and a method and apparatus for forming a double wall article with a pair of deformable thermoplastic sheets wherein the sheets are mounted, in face to face contiguous relation, on a single pair of laterally spaced longitudinally extending rails. The rail supported, contiguously disposed sheets are heated to forming temperature and are then subjected to differential forming pressures via a pair of opposed molds which seal to the sheets to fuze perimetrically extending, opposed portions of the sheets and form the border of the article being formed. Differential pressure is then applied to a central portion of at least one of the sheets within the formed border to withdraw the central portion and form the article.

Abstract: A cup-shaped deep-draw-formed article is formed by thermoforming a thermoplastic resin sheet characterized in that a concave forming mold and an ancillary mold which are in opposition to each other are used, said ancillary mold being equipped with a molding assist movable vertically to the opening face of the ancillary mold; the molding assist is first moved toward the opening of the ancillary mold; a preheated thermoplastic resin sheet interposed between said forming mold and ancillary mold is then expanded into the ancillary mold while moving the molding assist in contact with the sheet by introducing a pressured fluid into the forming mold; and when the molding assist reaches a predetermined position, a pressured fluid is introduced into the ancillary mold to press the sheet against the interior surface of the forming mold, thereby forming the sheet into the desired shape. This method can be applied to deep draw forming where the depth to opening diameter ratio is greater than 0.

Abstract: Plastics foil is shaped in a deep drawing apparatus by being placed in a mould, while the foil is below its deformation temperature, having heated wall surfaces and by applying a pressure differential to the foil so that it progressively stretches and contacts the mould wall. The progressive heating and stretching of the foil ensures that the corners of the moulded article are not thinner than the remaining portions of the moulded article, thus reducing the amount of plastics material necessary for an article of given strength.

Abstract: A mold construction, method and apparatus for forming backing shells for skating ring dasher boards out of a single piece of material is disclosed. The mold comprises a vacuum box and oppositely disposed forming members loosely positioned in the box to form a mold cavity. A sheet of plastic material is secured in a frame and is softened by radiant heat. The softened sheet is brought adjacent the mold cavity and is drawn into the cavity to assume the conformation thereof by air being withdrawn from the cavity through cracks therein resulting from the loosely fitting forming members. One or more layers of fiberglass and polyester resinous material applied to a face of the backing shell completes the dasher board.

Abstract: A stereo relief modelling apparatus based on photogrammetric method and apparatus comprising a flexible platen, used with standard stereo plotting instrumentation such as double-projection direct-viewing plotting instruments. The purpose of the flexible platen is to provide an absolute stereo image for photographic, modelling and other purposes. The flexible platen, which is of sufficient size to provide a meaningful mapping surface, is vertically adjustable at a multiplicity of points by mechanical, pneumatic, electro-mechanical, fully automated, or other means to provide an actual model-like three-dimensional photographic or modelling surface to enable relief distortion from aerial photographs to be effectively eliminated in planimetric photographs which are taken of the adjusted flexible platen, or models molded on the adjusted flexible platen, upon which the aerial images are projected. Modelling is facilitated by situating the platen inside a sealable vacuum box from which the air is removable.

Abstract: A technique for the manufacture of a resin-impregnated, reinforced article while resin fumes are prevented from escaping into the surrounding atmosphere.