Abstract: Straight walled hollow containers may be molded without taper, according to the present invention. Two mold halves, when brought together define a cavity configured to the outer wall of a hollow plastic container to be injection molded, and also an opening at one end of the cavity to enclose the stem of a core defining the inner wall of the hollow plastic container. When the core is disposed in the cavity, it is centered within the latter. Thereby a space is provided between the inner walls of the mold halves and the outer wall of the core to receive plastic material injected under high pressure through a sprue, also defined by the inner walls of the mold halves. After injection, the plastic is cooled to just below the softening point of the plastic. At this point separation of the mold halves surrounding the outer portion of the core, is commenced and a force is applied to initiate withdrawal of the core from between the mold halves.

Abstract: In a blow molding apparatus where a plurality of sets of molds are mounted on a wheel rotatable about an axis and the molds are moved toward and away from one another to enclose a parison and the parison is blown to the confines of the cavity between the mold sections as the wheel rotates by the application of air, an apparatus for controlling the application of the air comprising a valve assembly associated with each set of molds on the wheel and comprising a valve which is opened and closed to control the flow of air to the mold. The valve assembly includes a rotatable cam for moving the valve to open and closed positions, a starwheel associated with the cam, and a first actuator mounted at a first position along the path of the wheel for engagement with the starwheel to rotate the cam and open the valve and a second actuator mounted at a second position along the path of the wheel for engagement with the starwheel to rotate the cam and close the valve.

Abstract: Undercut tubular synthetic plastic articles, such as fittings, are formed in the mold cavity of an injection molding machine on a one- or two-piece core a portion of which is surrounded by the undercut portion of the article and a first smaller-diameter portion at one side of the undercut portion. If the core consists of two components, a cylindrical component of the core slidably guides the aforementioned portion and is surrounded by a second smaller-diameter portion of the article at the other side of the undercut portion.

Abstract: A method and apparatus is provided for trimming flash from the outer edge of thermoplastic molded records and then finishing the outer edge. A molded record having flash on its outer edge is supported on a turntable and then rotated about its center. The flash and the outer edge of the record immediately adjacent the flash are selectively heated, preferably by using a focused infrared lamp, to a temperature above the glass transition temperature. A cutter is then advanced tangentially through the flash to remove the heat-softened flash from the record. The trimmed outer edge is then finished by bringing a shaped surface into contact with the softened edge and holding it there while rotating the record until the outer edge has the desired finished configuration. The heating is discontinued and the trimmed and finished outer edge is allowed to solidify.

Abstract: Sensor arranged to detect the proper placement and quantity of one or more inserts in the cavity of an injection molding machine. The sensor is preferably formed of a spring-biased plunger through one of the cavity shells. A photodetector monitors the movement of the plunger as the cavity-forming shells are closed and activates an alarm signal if the plunger movement is excessive before detection of proper mold closure.

Abstract: In a twin screw extruding machine, a reduction gear system comprises a casing, an input shaft and two output shafts supported by said casing, each in alignment with a respective one of said screws. A respective first pinion is fitted to each output shaft, these first pinions being offset relative to one another in the axial direction. The first pinion on each of the output shafts is a helical pinion so as to develop a component of force in the axial direction opposite a reaction to the thrust exerted by the associated screw of the extruding machine. Two first helical gears mesh with the first pinion on each of said output shafts at diametrically opposite points thereon. A respective second helical pinion meshes with each first helical gear. Each of the second helical pinions is keyed to a respective thrust shaft. There is a respective thrust bearing at one end at least of each thrust shaft. A respective second helical gear is keyed to each thrust shaft.

Abstract: A process for injection compression molding ultra high molecular weight polyethylene having an intrinsic viscosity of 3 dl/g or higher measured at 135.degree. C. in decalin and a melt index of 0.01 g/10 min or less comprises,(a) heating the ultra high molecular weight polyethylene to 170.degree.-240.degree. C.,(b) adjusting the volume of the mold cavity V.sub.1 equal to the volume of the molded article V.sub.0,(c) injecting ultra high molecular weight polyethylene having a volume V.sub.0 into the mold cavity through a runner portion at a shear rate of at least 20,000 sec.sup.-1,(d) instantaneously expanding the mold cavity to adjust its volume V.sub.1 to satisfy the relation:1.2 V.sub.0 .ltoreq.V.sub.1at a time from T.sub.1 (immediately before completion of injection) and a time T.sub.

Abstract: A plunger injection molding machine for utilizing a liquid composition and in addition to the other usual features, a valve for allowing liquid composition to enter a barrel means; sealing means on the plunger which operates on the barrel of the machine so as not to allow the liquid composition to leak pass the sealing means out of the rear of the barrel means; and stop means to regulate or control the rear work movement of the plunger means out of the barrel means which results in accurate control of the amount of liquid composition forced into the mold. A preferable composition for use with this type of machine is a silicone composition and more specifically a SiH olefin platinum catalyst silicone composition.

Abstract: A device for preventing the leakage of a molten material remaining in the mold through the gate, the device including a specially designed valve members movable in opposite directions so as to effect the communication of the sprue with the mold and to form a negative pressure chamber therebetween, the negative pressure chamber being adapted to suck a molten material remaining in the mold whereby the internal pressure is vacated from the passageways in the mold. This prevents the molten material from leaking through the gate. When the negative pressure chamber is closed, the sucked molten material therein is expelled into the passageways.

Abstract: A mechanism for the clamping attachment of interchangeable injection molding dies to the die carrier plates of an injection molding machine featuring a plurality of clamping plungers in axial guide bores of the die carrier plates, each clamping plunger having a clamping nose engaging a clamping shoulder of an oversized back plate of the die half, clamping the latter against the die carrier plate, when it is forcibly retracted by means of a transversely guided wedge rod traversing the clamping plunger and driven by a hydraulic cylinder assembly in a self-locking taper drive configuration. The injection molding dies are insertable and removable in either a horizontal or a vertical direction.

Abstract: A hot sprue valve assembly is provided for controlling flow of molten material through a hot sprue bushing 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, and the valve assembly includes means for forming the central aperture in the disc. In one embodiment, the aperture-forming means comprises a sleeve valve for molding the aperture in the disc prior to solidification of the disc-forming melt, whereas in another embodiment the aperture-forming means comprises a punch for punching the aperture subsequent to solidification of the disc-forming melt.

Abstract: A temperature sensitive element comprises fine grain powders which consist of a spin reorientation type ferromagnetic material having a transition temperature range, below which transition temperature range the easy direction of magnetization of the spin reorientation type ferromagnetic material is predetermined in one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is a predetermined other direction perpendicular to the predetermined one crystallographic direction. The temperature sensitive element is produced by compacting the fine grain powders at a temperature higher than the transition temperature range. According to the present invention, it is possible to use a polycrystalline rare earth cobalt alloy material in the field where low Curie point ferrite has been used or where bimetals have been used for a thermal valve or a temperature controlling device.

Abstract: An automated system for controlling the curing process of structures formed of fiber-reinforced composite material and the like in an autoclave is disclosed. The system uses sensors to monitor autoclave pressure, ambient and structure surface temperature, and structure viscosity during the cure cycle. Real time measurements are taken for each of these parameters, and the measured values are compared with predetermined optimum values which themselves change as the curing cycle progresses. The results of the comparisons are used to control the application of temperature and pressure in the autoclave to achieve the desired visco-elastic states of the structure which continually change as the curing process progresses. The viscosity data are obtained through measurements of attenuation of an ultrasonic wave in the composite material of the structure. It was found that the attenuation is directly related to the viscosity of the structure.

Abstract: A core pin for use in a plastic injection mold for forming a hole through a part as it is formed in the mold. A shaft is longitudinally slidable in one of the base members of the mold and extends through the cavity of the mold and abuts the inner face of the opposing base member. A spring biases the shaft toward the second base member. When the mold is open the shaft has a small amount of positive clearance. When the mold closes the spring is compressed and the shaft has zero clearance against the inner face of the second base member, regardless of dimensional changes of the mold.

Abstract: The invention relates to a process for obtaining information-carrying disks by moulding from a recorded matrix. The invention makes it possible to obtain a disk having a recording area and intact areas, which are separated by stop areas. The invention more particularly applies to the production of video disks and disks useable in information technology. It facilitates the installation of covers on the disks.

Abstract: A high temperature refractory brick wall is repaired by removing and replacing damaged brick while the wall is maintained at a temperature below normal operating temperature but sufficiently high to avoid damage from contraction resulting from cooling. New brick having a coefficient of thermal expansion compatible with the heated wall are used to avoid cracking of the wall due to expansion during heat-up. Workers wearing protective clothing, preferably incorporating a circulating fluid cooling system, remove the damaged brick and install new brick in their place in walls having surface temperatures of about 500.degree. F. or higher and internal temperatures substantially above 500.degree. F., preferably at least about 1500.degree. F.

Abstract: A reusable form for a formed in place concrete pad positioned near a structure. The form including two spaced side beams of a predetermined length beam having first and second ends, each of the first ends are adapted to engage the structure in an abutting relation. The form further including a front beam engaging the side beams at said second ends; a pin hinge for connecting the front beam to the side beams proximate the second ends; and transverse stabilizer means mounted to and suspended above the side beams for establishing a parallel spacing between the side beams for squaring or establishing a perpendicular relation between the side beams and the front beam.

Abstract: An improved apparatus for producing concrete pipes includes a molding box and a pair of runner wheels for supporting the molding box. The box is vibrated while being rotated to disperse the components of ballast uniformly with sand and cement interposed therebetween. This apparatus makes it possible to produce concrete pipes having a higher strength.

Abstract: An injection mold comprising a fixed and a movable mold half and a demolding device for the moldings, which essentially consists of grippers and a kinematic chain, by means of which the opening movement of the mold half is transferable to the holders of the grippers. By this means, the opening movement of the mold half can cause the grippers to move towards the moldings to be taken out of the mold half.

Abstract: A plastic crate or tray comprises a bottom and vertical side walls. A side wall comprises inner and outer side wall parts.Injection molding points are present in the lower edge of the outer side wall parts.