Abstract: A hot sprue valve assembly is provided for controlling flow of molten material into the mold cavity of an injection molding machine. The valve assembly is particularly designed for use with an injection molding machine for molding centrally apertured record discs, such as video information discs. The valve assembly comprises a stationary valve body supporting a movable valve member for sliding motion toward and away from the mold cavity. The valve member includes a hot sprue bushing defining a heated flow path for passage of molten material toward the mold cavity, and a dispersion head carried by the bushing for directing the molten material to flow in a generally radially outward direction through gate passages with substantially uniform radial distribution into the mold cavity. In one position, the valve member is advanced into the mold cavity to align the gate passages with the mold cavity and thereby permit flow of the molten material into the mold cavity.

Abstract: A laminated recorded disc of the type having a core material surrounded by a surface layer of a conductive material is made from a preform having a core surrounded by the conductive material. The preform is made in a mold in which the conductive material is first injected into the mold and then the core material is injected into the conductive material. The disc is made from the preform by placing the preform between the platens of a compression mold and closing the heated platens against the preform. The heated platens heat and apply pressure to the preform to cause the materials of the preform to flow radially outwardly until the materials fill the mold cavity formed by the completely closed platens.

Abstract: A compression mold includes punch and cavity components fabricated from initially flat sheets of relatively thin metal. The sheets of each component are shaped, assembled and joined to provide box-like components defining mating mold surfaces yielding molded parts which may be straight or laterally and/or vertically curved. The hollow interior of the two components allows for the circulation therethrough of an appropriate heat transfer medium to permit molding of either thermosetting or thermoplastic compounds.

Abstract: A process for injection molding a polyester with improved crystallization thereof is described, which comprises incorporating, prior to molding, incorporating in the polyester as a crystallization accelerator a compound containing at least one aromatic ring selected from the group consisting of a benzene ring, a naphthalene ring and an anthracene ring; at least one sulfonic acid alkali metal salt group; and at least one phenolic hydroxy alkali metal salt group.

Abstract: In molding a number of articles of plastics at the same time with use of an upper mold and a lower mold having a multiplicity of cavities in the fitting surfaces thereof, a process for molding plastics by supplying the molding material to a plurality of pots each provided for one pair of cavities in proximity thereto, and injecting the material into the cavities from the pots through gates without passing the material through any runner. An apparatus for practicing the process is also disclosed. The waste of the molding material can be reduced at least by the amount conventionally needed for filling the main and auxiliary runners.

Abstract: A fluorocarbon polymer gasket is disclosed which has been compression formed from a fluorocarbon polymer sheet heated to its gel state, cooled in its compressed state, and shaped into a gasket. The gasket so manufactured has a "living memory" thus enabling it to tend to return to its pre-compression form when exposed to elevated temperatures.

Abstract: Method for the manufacture of flexible disks from engraved moulds by means of a compression press comprising starting with a roll of plastic material and bringing a strip of material between the open plates of a compression press without making a preliminary hole in said strip. A preliminary hole is made during the closing of the plates by means of a first punch matched to a complementary punch, said punches serving as centering means for the two moulds, then by the guidance of the first punch in the complimentary punch for the centering of the moulds with respect to one another. The central hole is cut when the plates are closed by means of the complementary punch which is maintained in the raised position throughout the end of the pressing cycle.

Abstract: A material injection assembly (10) of the type for injecting a resin material into a mold cavity including a body member (12) defining a nozzle (13) for injecting material into a mold (14) and including at least one central channel (16) for conveying a first material through the nozzle (13). The assembly is characterized by an internal purging mechanism for closing the nozzle (13) to the mold (14) while allowing the flow of purging material between the channel (18) supplying resin material to the control channel (16) and a debris channel (22). The purging mechanism further allows flow of purging material between a separate purging material channel (20) and the debris channel (22) to perform a post-purge function.A cooling system is also disclosed which provides a coolant supply channel (70) which bifurcates into two channels (75, 77) about the central channel (16) proximal to the nozzle (13) to provide maximum cooling at the portion of the assembly (13) closest to the mold (14).

Abstract: A machine for treating or processing, e.g. injection moulding or extruding, plastic material which is available in packaged form said machine comprising, in a manner known per se, an extrusion nozzle (7, 9) and a feed channel (23) connected thereto, is combined with a device (31) for emptying the packages into said feed channel by deformation of the package (71). Before the emptying exit openings may be provided in the packaging material by means of special perforating members (93 to 97). The deformation and the emptying of the package takes place in a cylinder (47) by means of a piston (45) fitting therein and driven by means of pressurized fluid.

Abstract: A molding machine for encapsulation including a transfer molding die provided with a plurality of pots which comprises a transfer molding press, a molding die including a plurality of pots allowing for the passage of plungers integrally formed with the rods of the cylinders, a plurality of runners branched off from the pots, a plurality of cavities connected to the runners through the corresponding gates, and displacement transducers for detecting the rate of the displacement of the plungers, variable flow rate control valves communicating with lines connected to the cylinders, and a control circuit for controlling the operation of the variable flow rate control valve in accordance with output signals from the displacement transducers, thereby causing the plungers corresponding to cylinders to be moved exactly at the same speed.

Abstract: A stationary platen of an injection-molding machine, carrying a mold portion with a sprue leading to one or more cavities, is connected by a set of metallic tie bars with a fixed part of the machine frame containing the mold drive and is limitedly slidable on the machine bed to an extent corresponding to the stretch of the tie bars under a mold-clamping force exerted by that drive upon another platen moving along the tie bars. An injection unit behind the stationary platen has a precompression chamber which communicates with a channel leading to an injection nozzle, this nozzle being received in a cutout of that platen and confronting the sprue through the head of a hollow gating plunger slidable in the nozzle orifice.

Abstract: An injection molding apparatus wherein an annular magnetic coil is disposed to enclose the outer periphery of a mold when it is clamped and to move in the directions to open and close said mold. An injection molding apparatus comprising, a stationary mold, a moving mold made movable to and from said stationary mold for forming an injection molding cavity together with said stationary mold, a magnetic coil movable back and forth in cooperation with the operation of said movable mold and adapted to enclose the outer peripheries of the two molds clamped.

Abstract: A method and apparatus is provided for repairing the worn tap hole of a steel converter to restore same to a desired diameter wherein elongated jet spray means are placed centrally into and in close proximity to the surface of the damaged tap hole and thereafter refractory mortar repair material is sprayed against the surface of the inner circumference of the worn tap hole wall to restore the diameter of same to the desired dimension.

Abstract: A compaction device for compacting powder in which a compaction chamber (16) is formed by a block (1) having a conical bore (9) and a conical sleeve (2) being movable in the bore to be compressed thereby. The taper of sleeve (2) is somewhat smaller than that of the bore (9). A combined shock absorber and extractor, for the compacted powder, which comprises a movable support (4) extending into the compaction chambers (16) and being provided with an enlarged head portion (13) having passages (14). An accumulator (42) is connected to a chamber (22) of the cylinder (11) in which support (4) is movable. The accumulator (42) improves the shock absorbing characteristics.

Abstract: The apparatus has a plurality of open-ended female dies with a movable lower male die positioned in the lower end of each one. A supply box is shiftable over the female dies to deposit concrete therein, following which a plurality of upper male dies are moved down into the female dies to compact the concrete therein into chairs. Wire supply means feeds wires through the upper male dies and into the concrete in the female dies before the concrete is compacted. After the wires have been cut above the female dies, the upper male dies are retracted and the lower male dies are moved upwardly to eject the compacted chairs from the female dies.

Abstract: Video discs are dried by first spraying the surface with liquid fluorocarbon to remove water and heating the disc so as to prevent water condensation during evaporation of the fluorocarbon, preferably in a fluorocarbon vapor.

Abstract: In a method and apparatus for casting or molding cages for rolling elements, two slides are provided for each pocket. The slides have an engaging, inclined surface, and are shaped to permit one of the slides to be removed by initially sliding it along the inclined surface. The other slide may thereby be moved laterally in the formed pocket, and withdrawn from the pocket. Facing slides of adjacent pockets may be joined together, with limited movement possible therein, to form a complete ring serving as a mold member.

Abstract: In a method of molding a large plastic structure which includes applying a vacuum to draw the molds together, injecting resin into the space between the molds while the vacuum is applied, maintaining the vacuum at least until the resin gels, removing the vacuum, allowing the molded structure to harden, removing the male mold and then removing the molded structure, molding is carried out on a moving production line without danger of disturbing the resin while gelling by disposing the molds on bogies and moving the bogies onto motor driven glide rollers at the point where the resin is injected, and the bogies transported on the glide roller drive until initial gelling has taken place.

Abstract: A safety cover assembly for the die closing unit of an injection molding machine having three jointly or separately openable safety gates on the front, top and rear of the unit supported in a cantilever-type guide arrangement on a U-shaped supporting frame, and a stationary cover assembly attached to the same frame and forming pockets into which the safety gates are retracted when opened. The supporting frame consists of three identical frame members, each carrying a safety gate and a gate drive in the form of a timing belt loop, as well as safety interlock switches and a safety interlock linkage for the operation of hydraulic and/or mechanical interlock devices. One frame member also carries a die displacement measuring unit.

Abstract: A drive-reversing safety mechanism using a pivotable contact ledge on the leading edge of a mechanically openable and closable safety gate of an injection molding machine, the pivot axis being arranged at a flange corner of the safety gate, where the channel-shaped contact ledge engages the outside of the corner with a fillet of a ledge fold. An adjacent positioning flange of the contact ledge is yieldingly clamped to the safety gate by means of pins and compression springs. An actuator plate attached to the contact ledge cooperates with a switch controlling the safety gate drive.