Abstract: A press system that provides rapid advance of one platen on a movable crosshead through the use of programmed hydraulic controls and is specifically adapted for use with sheet molding compound (SMC) presses. Rapid locking or latching of the crosshead and the platen it carries is achieved through the use of hydraulically operated clamping and release cylinders. The lower platen is supported on hydrostatic bearings permitting the platen to move and at the same time parallelism of the mold halves is maintained by swiveling molding power cylinders. Separate push-back cylinders are used to separate the mold through a short load path so that when the mold "breaks away" there is very little springback to minimize any part breakage during mold stripping.The lower platen also includes a mounting arrangement that provides the advantages of a rolling bolster or lower platen with a minimum of mounting structure.

Abstract: An extensometer readout circuit conditions a strain information signal, representing strain of a specimen being tested, in such a way that yield point measurements and final elongation measurements of such specimen may be concurrently obtained. The strain information signal is provided by subjecting the specimen to a tensile or compression test by any conventional means known in the prior art. The strain information signal is first applied to a preamplifier. The preamplified strain information signal is then concurrently applied to both a high gain amplifier and a low gain amplifier. The signal obtained from the high gain amplifier is used for performing modulus calculations and for obtaining yield point measurements. The signal obtained from the low gain amplifier is used to obtain the total elongation measurement.

Abstract: A "mode switch" is used for smoothly switching a servovalve controlled device such as an SMC press, in particular, from control under one parameter to control by another. The mode switch provides a very smooth transfer of control from displacement control between two relatively movable parts to force control to provide for controlling the force exerted by actuators acting between the two parts. The mode switch electronically tracks the signals so that when the switching is made the signals are precisely equal to prevent abrupt changes in the control signals. This smooth transfer is achieved even under active control, that is when both control signals are changing in value.

Abstract: A press system that provides rapid advance of one platen on a movable crosshead through the use of programmed hydraulic controls and is specifically adapted for use with sheet molding compound (SMC) presses. Rapid locking or latching of the crosshead and the platen it carries is achieved through the use of hydraulically operated clamping and release cylinders. The lower platen is supported on hydrostatic bearings permitting the platen to move and at the same time parallelism of the mold halves is maintained by swiveling molding power cylinders. Separate push-back cylinders are used to separate the mold through a short load path so that when the mold "breaks away" there is very little springback to minimize any part breakage during mold stripping.The lower platen also includes a mounting arrangement that provides the advantages of a rolling bolster or lower platen with a minimum of mounting structure.

Abstract: A transducer arrangement provides a feedback signal which indicates the position of a first part relative to a base and when a second movable part is positioned adjacent the first part the transducer provides a signal indicating the spacing between the two parts. Specifically the transducer provides for spacing control between the two halves of a mold mounted in a press wherein a crosshead moves a substantial distance and carries one part of the mold (the upper half) relative to the lower mold part. Hydraulic actuators act on the lower part of the mold to provide the molding force when the mold parts are close together. The transducer is mounted in a housing and arranged to provide a signal used for controlling the hydraulic actuators to control the spacing of the two molds parts unitl the mold parts are separated a known amount, after which the hydraulic actuators are controlled by sensing the spacing of one mold half relative to the base of the press.

Abstract: An improved rotary actuator assembly includes a stationary shroud extending between first and second spaced apart stationary support members that aids assembly of the rotary actuator and collects drain lubricating oil during operation. A rotating member is supported between the first and second stationary supports by bearings positioned within the first support and a bushing within the second support. The shroud covers a portion of the rotating member between the first and second stationary supports.

Abstract: The flat belt tire tester which permits mounting a wheel and tire to be tested about an axis positioned above a flat belt, and has framework and controls for lowering the tire into contact with the belt under desired loads, using desired adjustments for camber and steering. The belt is powered, and can thus be used for testing the tire under simulated road conditions. The mounting framework and belt mounting construction of the present invention provides substantial rigidity through having the mounting frame geometry properly oriented in relation to the contact surface of the belt and also by providing a stiff frame for the belt mounting drums or pulleys.

Abstract: A linearization circuit for use with servovalves for controlling reciprocating actuators. The circuit will maintain a substantially linear flow as a function of spool position from the servovalve regardless of the differential pressure across the servovalve orifices, for example the differential pressures which result from changing direction of movement of the controlled actuator under a high load. A differential pressure signal from the actuator, which correlates to differential pressure on the servovalve orifices is processed to provide a compensation signal combined with the normal control signal to achieve the desired output.

Abstract: A bearing support for a flexible belt used on a tire testing machine wherein the belt forms the simulated road surface. The bearing is a hydrodynamic bearing which insures low friction between the belt and its support underneath the tire being tested.

Abstract: A swivel joint which has two mating part spherical reaction surfaces carried on two loading members. One of the surfaces is defined in part on a piston which is urged under pressure toward the mating part to take up backlash between the mating surfaces. A sealed area may be defined between the mating surfaces and which contains a quantity of fluid under pressure to carry the loads between the two surfaces on a hydrostatic bearing. The swivel joint permits high loads from hydraulic actuators to be supported without encountering high friction forces while permitting swiveling of the joint across a substantial range of angles.

Abstract: The present invention relates to single actuator blanking and draw pad force control for a drawing press, which includes a unique swivel for the hold down pad comprising a confined elastomeric member which has high axial stiffness, but relatively low rotational or pivoting stiffness about an axis normal to the actuator axis. Further, the pad can be combined with air pressure for holding a sheet of material during the blanking and drawing operations.

Abstract: A railroad side frame test machine for loading side frames used on the trucks or carriages for railway cars to simulate the in-use loads utilizing a compact linkage that provides for direct loading of the specimen in the various load directions. The forces are applied to the specimen to insure that certain reactions are grounded, while other applied forces are basically ungrounded to effectively eliminate "cross talk" between the various input loads or forces.

Abstract: A high volume valve for controlling flow of fluid from a source of fluid under pressure, such as in an accumulator, to an actuator used for testing specimens under high rates of loading. The valve includes a poppet type valve piston that is normally held in a closed position by hydraulic pressure behind the poppet, and when the pressure holding the poppet closed is released, the main supply of fluid under pressure acts on the poppet to open it very quickly. A second accumulator open to the opposite side of the poppet from the main source of pressure is utilized for controlling speed of opening of the valve. The amount the poppet opens also can be adjusted for controlling the rate of flow of fluid from the main source of pressure to the actuator.

Abstract: A rapid opening valve assembly utilized in high rate specimen test systems which require that an actuator load a specimen at rates in the range up to one thousand inches per second and with deflections up to three inches. The high rate valve utilizes a poppet or valve piston member that rapidly opens once it is triggered. The ports may be very large and as shown the valve body is used in connection with a closely coupled accumulator pressure source that is ported directly to the actuator to provide adequate flow capacity. The specimen is generally for testing of metals, plastics, and elastomers under tension or compression.

Abstract: A test system for testing axles and wheel spindles directly in place on vehicles such as automobiles, which simplifies the loading to obtain the necessary information for testing axles and spindles using two sets of actuators, each set comprising a pair of actuators each operating to control loads on the spindle along two different orthogonal components of normal movement of the vehicle. The actuator arrangement saves space, permits testing without removing automotive sheet metal and simplifies the compensation factors necessary for controlling such systems.

Abstract: The present invention relates to single actuator blanking and draw pad force control for a drawing press, which includes a unique swivel for the hold down pad comprising a confined elastomeric member which has high axial stiffness, but relatively low rotational or pivoting stiffness about an axis normal to the actuator axis. Further, the pad can be combined with air pressure for holding a sheet of material during the blanking and drawing operations.

Abstract: The flat belt tire tester which permits mounting a wheel and tire to be tested about an axis positioned above a flat belt, and has framework and controls for lowering the tire into contact with the belt under desired loads, using desired adjustments for camber and steering. The belt is powered, and can thus be used for testing the tire under simulated road conditions. The mounting framework and belt mounting construction of the present invention provides substantial rigidity through having the mounting frame geometry properly oriented in relation to the contact surface of the belt and also by providing a stiff frame for the belt mounting drums or pulleys.

Abstract: A load frame used for testing purposes which includes means for reacting side loads between upper and lower cross heads of platens of a press or load frame.

Abstract: A linear spring system using pneumatic cylinders arranged to give a substantially linear force versus displacement curve across a wide range of displacement and which is capable of providing large forces with mechanism.

Abstract: A test system for testing specimens to determine crack propagation utilizing a factor relating to stress intensity at the end of the crack as a control parameter for the loading means.