Abstract: An automatic purging method for an injection molding machine which is capable of injecting an arbitrary material among different kinds of materials into a mold without requiring a resin replacing block or a purging container and an additional material supply means for increasing the material supply pressure, and which has a nozzle valve in a nozzle unit. This method is used so as to enable the automatic purging to be done smoothly and speedily by operating the nozzle valve so that it behaves according to a predetermined program. This automatic purging method consists of the steps of supplying a fresh material from a hopper (7) into a screw cylinder (1), rotating a screw with a nozzle valve (4) closed, for a predetermined period of time or until the screw has been moved back a preset stroke, to plasticize the resin, and then purging the molten resin with the nozzle valve (4) set to a predetermined degree of opening.

Abstract: A method of and apparatus for controlling an injection molding machine by reproducing injection time and stability of an inspection speed to thereby improve precision, stable moldability. In the injection molding machine, a nozzle valve (4) for changing the opening of this nozzle is disposed at the tip of the nozzle for injecting a molten resin, the degree of opening of this nozzle valve (4) is controlled to a predetermined quantity of opening in accordance with a preset screw moving position and the flow rate of an operation oil for pushing a screw (6) is controlled in accordance with the degree of opening of the nozzle valve (4).

Abstract: A control apparatus for an injection molding machine injects a melted resin within a housing into a cavity of a mold through a nozzle section of a nozzle at a housing and by movement of a screw. A nozzle opening changing mechanism variably changes a throttled path area of the nozzle while a mold temperature sensing mechanism sensing the temperature of the mold. A control mechanism controls the nozzle opening changing mechanism in accordance with the sensed temperature of the mold temperature sensing mechanism.

Abstract: An injection molding machine of the present invention has a flow rate control device (11) located between an injection screw (2) mounted inside a housing (1) so that it may be rotated freely and reciprocated freely and an injection nozzle (12) mounted in the leading end of the housing (1) so as to inject the molten resin into a cavity (14) of a mold (13). The control device serves to control the rate of flow of the molten resin from the injection screw (2) to the injection nozzle (12). The flow rate control device (11) cooperates with an injection speed control device and a dwell pressure control device installed separately to control the flow rate and speed of the molten resin thereby making it possible to control the injection speed rapidly, and with a high accuracy and with an excellent response.

Abstract: A spring applied and hydraulically released motor shaft brake apparatus for a hydraulic motor which is compact in size. The brake apparatus includes a piston slidably mounted in a cylinder defining a brake chamber and a drain chamber. The piston is slidably and rotatably mounted on the motor shaft and a spring is disposed in the drain chamber for biasing the piston towards the brake chamber to thereby lock the motor shaft against rotation. The brake chamber is selectively connectible with a pressurized fluid source while the drain chamber is connected with a drain. The piston has formed therein a passage with a restrictor disposed therein for restricting flow of fluid in the passage.

Abstract: A hydraulic brake valve system for use in a hydraulic circuit consisting of driving and braking fluid lines and including therein at least a hydraulic motor for the actuation of an inertia body such as, for example, a construction vehicle or work implements thereof has a counterbalance valve, a cross-over safety valve, a drain change-over valve and a timer valve. The cross-over safety valve consists of two common relief valves, each having two pressure receiving surfaces and adapted to relieve pressurized fluid acted on one of the pressure receiving surfaces at a low pressure and relieve pressurized fluid acted on the other pressure receiving surface at a high pressure, wherein the first port of one of said relief valves is connected with said driving fluid line and the second port thereof is connected with said braking fluid line, whilst the first port of the other relief valve is connected with said braking fluid line and the second port thereof is connected with said driving fluid line.

Abstract: A flow divider valve assembly for dividing a flow of fluid between a priority flow device, such as a power steering system, and an excess flow device, such as an auxiliary mechanism. The flow divider valve assembly comprises a valve body defining an inlet port to be connected to a source of fluid under pressure, a priority flow outlet port, an excess flow outlet port and a valve bore interconnecting the ports, and a valve spool axially movable within the valve bore, the valve spool having formed therein an axial bore for permitting a constant communication between the inlet port and the priority flow outlet port. A first restrictor is disposed between the inlet port and the priority flow outlet port and a second restrictor is disposed between the inlet port and the excess flow outlet port. Restriction rate of the first restrictor is made larger than that of the first restrictor.

Abstract: A hydraulic circuit for steering control in articulate vehicles which comprises an engine, a fixed displacement pump driven by the engine, a variable displacement pump driven by the engine, an exit port of the variable displacement pump being connected to a control valve of a steering actuator, an orifice provided at an outlet side of the fixed displacement pump and, a controlling cylinder connected to the variable displacement pump for controlling displacement of the variable displacement pump, the controlling cylinder being actuated by a spring disposed therein and a differential hydraulic pressure at the orifice.

Abstract: A hydraulic circuit for controlling actuators in a construction vehicle which comprises an engine, a fixed displacement pump driven by said engine, a variable displacement pump driven by said engine, a controlling cylinder connected to the variable displacement pump for controlling the displacement thereof, an orifice provided between the output of the fixed displacement pump and a tank and, an unloading valve connected to the fixed displacement pump and also to the variable displacement pump via a pilot line for selectively unloading an output fluid from the fixed displacement pump when it is open.