Abstract: In an injection molding machine of the type comprising an injection cylinder, a feedback circuit for feeding back the oil in the rear chamber of the injection cylinder into the front chamber thereof and a booster cylinder, a pressure oil accumulator is connected to the booster cylinder through a valve for supplying pressurized oil for actuating the booster cylinder. A check valve is connected in parallel with the valve. When water hammer occurs at the end of the injection stroke the check valve opens to absorb the energy of water hammer by the accumulator.

Abstract: A shot tip assembly for an injection molding machine of the type having a shot tube for conducting molten material into a die cavity of the machine. The shot tip assembly has a shot tip which is reciprocal within the tube and forms a close sliding fit with the tube for forcing the molten material through the tube and into the die cavity. A shot tip adapter is provided for the shot tip and has one end captively but relatively movably mounted in the shot tip, the adapter being connected at the other end to a reciprocal shot rod. A movable or swivel connection is provided between the adapter and the tip to permit the tip to move or swivel slightly on the adapter to thereby accommodate any misalignment between the shot tube and the shot tip as they are moved relative to one another. The injection machine with which the shot tip assembly is used has power means for example, a hydraulic shot cylinder for driving the shot rod, and consequently, the shot tip in the shot tube.

Abstract: The installation comprises a pressure tight casing with vacuum melting and casting chambers communicating with each other via a pressing chamber. The vacuum melting chamber accommodates an electrode holder arranged above a melting pot. Located under the melting pot is a pouring device with funnels, one of which is inserted into a hole in the shell of the pressing chamber. The vacuum melting chamber incorporates an appliance for cleaning the used funnels and a mechanism for moving the funnels. The pressing chamber communicates with the pressmould. One half of the pressmold is secured on an immovable vertical plate and the other half is mounted on a movable vertical plate. The movable vertical plate travels over horizontal guides.

Abstract: In a die casting machine a shot of molten material is transferred through an injection tube at a relatively slow speed so that all the gas present in the tube is forced out through the associated die. When a first portion of the molten material reaches the die cavity, the event is automatically sensed by circuitry which commands the machine to transfer the remainder of the molten material through the injection tube at a relatively fast speed and cause injection thereof into the die.

Abstract: In a vertical die casting machine of the type wherein molten metal contained in a vertical casting sleeve located beneath a stationary platen is cast into a die cavity defined between a stationary die and a movable die urged against the stationary die, the casting sleeve is divided into an upper and a lower part. The upper casting sleeve is secured to the stationary platen in communication with the die cavity. The lower casting sleeve is normally held in vertical alignment with the upper casting sleeve but is moved to a position lateral to the stationary platen for receiving the molten metal. When the lower casting sleeve is returned to the normal vertical position it is urged against the upper casting sleeve and molten metal in the lower casting sleeve is teemed and cast into the die cavity by operating an injection plunger.

Abstract: In a die cast machine of the type wherein the piston of an injection cylinder is advanced by pressure gas admitted into the rear chamber of the cylinder while discharging pressurized liquid in the fore chamber, and the piston is retracted by pressurized liquid admitted into the fore chamber while forcing the gas in the rear chamber back into a gas accumulator, a control valve device is provided in the path of the pressurized liquid discharged from the fore chamber, and the control valve device is controlled so as to vary the flow quantity of the discharged pressurized liquid in accordance with the position of the piston during its forward movement. There are also provided two gas accumulators which are connected to the rear chamber of the cylinder through a valve device which is controlled so as to adjust the rate of increase of the pressure applied to the molten metal at the final stage of the injection casting operation.

Abstract: In injection apparatus of the type wherein molten metal is injected into the metal mold of a die casting machine by an injection plunger and the fluid pressure acting upon the injection pressure is increased by a booster piston at or near the end of the forward stroke of the injection piston by means of a booster cylinder, a limit switch is mounted along the path of the forward stroke of the injection piston to be operated thereby as so to operate the booster piston at any desired point of the forward stroke.

Abstract: A shot sleeve, for receiving a metered quantity of melt through an inlet or filling opening and connected to the mold cavity, has its volume continuously diminished in such a manner as to maintain a constant communication between the space above the melt in the shot sleeve and the mold cavity for escape of all the gas or air above the melt into the mold cavity before the opening of the shot sleeve into the mold cavity is completely closed by the advancing melt. This is effected, during the shot-pre-filling phase, by an accelerated motion of an injection piston from a rest position, at which the filling inlet to the shot sleeve is open, through the shot sleeve toward the mold cavity opening. As a result of the accelerated motion of the piston, the melt spreads over the melt engaging surface of the injection piston and the formation of a standing wave is prevented.