Abstract: Liquid reaction molding (LRM) shot size and ratio control is achieved using a programmable controller (microprocessor) to select on a first-come-first-served basis one mold from among several and to manipulate a plunger metering pump system by retracting each of a pair of pump plungers to the same position each time the system is reset and to decompress or reduce pressures after injection. Each and every shot is started from this uniform reset position. Later steps in the sequence are: taking the hydraulic slack out of each pump system by prepressurizing which is done by advancing each plunger from said position independently until each and all liquid systems reach a threshold pressure (which pressure may differ from one liquid system to the other), feeding the shot size or quantity of each liquid (i.e.

Abstract: A coupling includes an outer cup-shaped member which acts as a support for other portions of the coupling and which itself is revolvably supported on a conveyor that moves the coupling between workpiece loading and unloading stations. The outer cup-shaped member acts as a shield against ambient conditions which may include heating, coating or other processing means. One embodiment of the invention has a plurality of fingers mounted to move radially inward of the coupling to grasp the workpiece, which fingers are mounted to form a part of the outer shield or wall at the time that they are grasping a workpiece. Another embodiment of the invention involves an internal chuck sort of coupling using an expandable resilient member which can be an elastomeric ring to expand outwardly into a grasping relationship with a hollow portion of the workpiece. The coupling and conveyor are suited for use in handling soft or easily marked materials such as plastic, soft metals and the like.

Abstract: A coupling includes an outer cup-shaped member that acts as a support for other parts and is both revolvably and slidably supported on a conveyor that moves the coupling between work stations. In the normal installation, the coupling would move between workpiece loading and unloading stations. Slide motion relative to the conveyor is used to engage and disengage a workpiece. The outer cup-shaped member acts as a shield against ambient conditions which may include heating, coating or the like. The coupling preferably involves an internal chuck feature having an expandable resilient detent member preferably in the form of a metallic stretchable annular member known as a garter spring. The coupling and conveyor are suited for use in handling soft or easily marked materials such as plastic.

Abstract: A nozzle shut-off valve for an injection molding machine has a plunger mounted to reciprocate in a bore so as to block the passageway of the plastic through the nozzle, a single-acting pneumatic piston and cylinder to reciprocate the plunger, to block said passageway, and a pilot passage connecting the underside of the plunger to a location upstream of the intersection of the bore and the passageway for plastic through the nozzle.

Abstract: A manually operated four bar linkage on a conveying device permits manual removal of preforms or other workpieces when they have not been ejected from the device at the desired unloading station. The linkage device has a cam track located adjacent to the return path of an endless type conveyor. The cam track is manually brought into conjunction with the couplings or collets which have accidentally retained a preform to force the coupling mechanism to move to a release position thus enabling manual removal of the preform. Preferably a bar or similar knock-out device is located downstream of the point where the cam track engages the coupling to ensure that all such preforms or other workpieces are removed.

Abstract: A mixing and dispensing apparatus for liquids that react chemically with each other from plural independent sources mixes same, and then cleans itself by injecting a terminal portion thereof into a mold. The mixing and dispensing means is intended to be incorporated into a system that provides measured quantities of the respective liquids, has control valving external of the mixing and dispensing means of the invention, and can recirculate the respective liquids except during actual mixing and dispensing. The mixing and dispensing apparatus has porting and passageways in its housing to permit recirculation and has a plunger which can be adjusted in its stroke to cover or uncover a certain amount of the mixing ports through which the respective liquids flow into the mixing chamber thence into the mold cavity.

Abstract: An injection molding machine has an improved lock and block system wherein the lock recess on the ram is defined between the parallel faces of a pair of spaced apart rings. The lock recess is established at a preselected position by sliding various ones of the rings longitudinally forward or rearward on the compression ram to coincide with a preselected advance position of the compression ram (blocking ram) on which is mounted the movable platen. The rings may be spaced apart by a magnetic spacer which is positioned where it will not be struck by moving parts of the machine. At least one jackhole or toolhole is provided in the side of the ring so that it can be separated from adjacent machine elements during set up operations.

Abstract: Apparatus is described for the controlled mixing of liquids in a predetermined ratio and is especially suitable for the dispensing of predetermined ratios of polyol and polyisocyanate liquids in the liquid injection molding of polyurethane articles. The ratio control is achieved by a master-slave velocity relationship between at least two metering pumps of the plunger or piston type which are velocity coupled and inject on a common programmed velocity profile that is fed into the pump control that is the master system. Each pump control system has a velocity feedback control loop (a closed loop system) and one signal into the slave automatic control system (typically the polyol system) is obtained in a suitable ratio from the feedback master automatic control system (typically the poly isocyanate system).

Abstract: A press mechanism that is powered by hydraulic, electrical and/or pneumatic means is provided with an improved ratchet and pawl machine which acts as a fail-safe device should any of the power means fail to lock the press parts in place. The fail-safe device includes a ratchet in the form of a circular or arcuate segment mounted with its circular center substantially coaxial with one of the turning parts of the mechanism or press, a pawl having a single tooth and a circular arcuate peripheral part that acts as a journal bearing and which in turn is supported by a pawl bearing which in turn is secured to a stationary part of the mechanism and has an arcuate journal which receives and supports the pawl therein. Tremendous load carrying capacity is thus achieved because of the large bearing area provided by the pawl bearing and the positioning of the respective ratchet and pawl teeth to employ a surface rather than point contact.

Abstract: Method for the controlled mixing of liquids in a predetermined ratio and is especially suitable for the dispensing of predetermined ratios of polyol and polyisocyanate liquids in the liquid injection molding of polyurethane articles. The ratio control is achieved by a master-slave relationship between at least two metering pumps of the plunger or piston type which are position coupled and inject on a common programmed velocity profile (in the master system), but with each system controlled by an automatic velocity feedback control loop (a closed loop system) wherein the reference signal into the slave automatic control system (typically the polyol system) is obtained in a suitable ratio from the master automatic control system (typically the polyisocyanate system). The method includes continuing to drive the metering pumps past the time that mixing is cut off.

Abstract: A clamp for holding together the portions of a mold used in molding solid objects from a reacting liquid such as polyurethane has a C-shaped frame which is pivotally mounted on a pedestal to swing through an arc. The C-shaped frame of the clamp consists of an integral structure having an upper jaw connected by a column to a lower jaw. The frame supports a bed, crown and platen. The bed and crown are each a plate-like member that is mounted to pivot relative to one of the jaws. The platen is mounted preferably on the bed or lower one of such members. The mold portions are mounted on the crown and platen with the parts being arranged to move so that the mold portion engage and disengage. The invention also includes a method of molding wherein the mold portions are engaged and disengaged by a process that involves pivoting at least one and preferably both of the portions relative to the C-shaped frame.

Abstract: A coupling includes a pair of cup-shaped members with one mounted for sliding axial motion inside the other. The outside coupling acts as a support or base which is connected to a conveyor that moves the coupling between workpiece loading and unloading means. The inside member also carries detents which move radially in and out to grasp or release the workpiece in response to axial motion between the two cup-shaped members. When combined with a conveyor, appropriate cam and follower means are provided to cause the coupling to be operated for grasping and releasing the workpiece in a timed sequence and to move the coupling from a workpiece loading station to an unloading station. The coupling and conveyor are suited for use in handling soft or easily marked materials such as plastic, soft metals, and the like. A method for workpiece handling includes steps of rotating, advancing in stop-and-go fashion while continuously rotating, and unloading.

Abstract: An electrohydraulic servo system is compensated by an electrical control system and has a position related feedback loop and a servovalve with a differential pressure transducer connected as a feedback loop between the output and return lines that extend to a hydraulic motor or other driven means from said servovalve.