Abstract: A self-compensating support skate (46) for an annular hydraulic ram (15) mounted in the front stationary platen (10) of a “two-platen” injection molding machine (1) is disclosed. The hydraulic ram (15) fits into a central bore (22) in the stationary platen (10) and connects directly to a relatively thin die platen (11) that provides a mold mounting surface. The purpose of the skate (46) is to prevent movement (tilting) of the die platen (11) and the resulting misalignment with the movable platen (20) when the mold (30) is attached. The skate (46) is adjusted during assembly to compensate for the tolerance stack-up in the ram assembly. The “zero” clearance is maintained by disc springs (56) within the skate (46) that compensate for the expansions and contractions of the large diameter parts due to temperature variations. The die platen (11) is held in the aligned position by contact with the lower tie rods (7).

Abstract: A method and apparatus for automatically setting the die height platen on a toggle-operated injection molding machine to achieve a desired mold clamping force. A control is provided and contains information relating a desired clamp tonnage with a toggle crosshead displacement, in order to permit setting the die height platen for a particular set of molds so that the clamp, when operated, will automatically provide the desired clamping force between the mold members. The adjustment is provided by moving the die height platen in response to deviations from a predetermined set of conditions, the die height platen being moved by an hydraulic motor and chain drive to shift the die height platen along guide rods that extend between the die height platen and a stationary mold platen.

Abstract: A hydraulic injection molding machine incorporates a pump driven by a variable speed motor preferably of the brushless DC type. The machine controller outputs driving signals to adjust the speed of the motor so that the flow delivered by the pump substantially matches the hydraulic demand imposed during each phase of the machine operating cycle. The pump is preferably a variable displacement type and is connected to a fast responding pump control for selectively carrying out pressure compensation or flow compensation. The values of the motor driving signals are calculated so that the motor/pump combination is operated at or near maximum efficiency except when the pump control varies the displacement of the pump to effect pressure or flow compensation. Hydraulic transient response is further improved by connecting the output of the pump to an accumulator by way of a check valve.

Abstract: An improved computer controlled hydraulic system for a conventional toggle-operated plastic injection molding machine comprising an injection assembly and a mold clamping assembly. The hydraulic system includes a first low volume pump and a second high volume pump connected between a reservoir of hydraulic fluid and a pressure and flow control manifold. The output of the pressure and flow control manifold is connected to an injection control manifold, in turn conected to and operating the instrumentalities of the injection assembly. The output of the pressure and flow control manifold is also connected to a clamping control manifold, in turn connected to and operating the cylinder of the clamping assembly. An isolation manifold is connected between the pressure and flow control manifold and the clamping control manifold. A third low volume pump is connected between the reservoir and the isolation manifold. The isolation manifold is also connected to the reservoir.

Abstract: Safety locking structure to prevent unintentional disconnection of a mating pair of male and female electrical connectors. The locking structure comprises a hollow tubular shell and a U-shaped clevis pin having a base portion and a pair of legs. The mating end of a first one of the electrical connectors is insertable into the shell from one end thereof and is captively held therein. The other end of the shell is provided with two pairs of aligned holes, each pair being adapted to receive a leg of the U-shaped clevis pin with a portion of each clevis pin leg extending into the interior of the shell. The mating end of the second one of the connectors is insertable into the shell from the other end thereof and into mating relationship with the first connector.