Midland-ross Corporation

Chandler Evans Inc.

Roger C Popp

Disclosed is a solenoid valve which is useful essentially as a control device for pressure-actuated equipment which responds proportionally to an electric signal transmitted to the valve in accordance with the strength thereof. The valve functions in perhaps its most important utilization to maintain a static pressure which may be varied in accordance with the strength of the current supplied to the solenoid of the valve. The valve is constructed for operation by which an output pressure is modulated, according to the current strength of the solenoid, between two supply pressures admitted to separate portions of the valve. One supply pressure is lesser and the other is greater than generally contemplated output pressure.

Electrically responsive static-pressure regulating valve

Described herein is a valve sub-assembly which, e.g., functions as a portion of a modulating valve preferably subjected to operating pressures of less than two atmospheres. This sub-assembly is especially designed to reduce hysteresis in the response of the valve to signal media. Hysteresis reduction is achieved through a departure from conventional sealing mechanism designs which achieves a reduction in the friction involved in the operation of conventional modulating valves.

Modulating valve sub-assembly

Disclosed is a pressure-sensing transducer in which a transducing unit comprising a semiconductor-type strain element is confined within a housing defining a generally funnel-shaped chamber. The unit is supported within the housing in spaced relationship with the surface of the chamber by an electrically non-conductive cup-shaped member of relatively rigid material, and a resilient electrically non-conductive ring which is yieldably deformed by sealing engagement of outer peripheral surface portions of the ring with the chamber and the inner cup surface of the member, and the inner periphery of the ring with the outer circular surface of the unit. A viscous flow-resistant, electrically non-conductive liquid occupies any open space in the chamber for communicating pressure from a pressure source through the small end of the chamber to the element within the unit.

Pressure-sensing semiconductor transducer

Disclosed herein is a trailer brake control system comprising a trailer-mounted servo-motor type booster in direct operating connection, e.g., by hydraulic lines, with the trailer wheel brakes, an electrical transducer and signal amplification apparatus mounted on the towing vehicle, and a solenoid synchronizing valve for controlling the booster operably positioned between the signal amplification apparatus and the booster for translating electrical signals of varying magnitude into correspondingly varying brake action. The system enables the operator of a tow vehicle and trailer combination to operate the trailer brakes with power-applied effort which is proportional to manual pedal effort applied to the braking system of the tow vehicle, or optionally, to operate the trailer brakes independently of the tow vehicle brakes to any extent desired through manual control of the signal amplification apparatus.

Pneumatically controlled hydraulic trailer brake system

A hydraulic booster has its piston located in a normal passive position so that hydraulic fluid supplied to the cylinder through an inlet port enters the cylinder on both sides of the piston. Normally open valve means establishes communication through the piston from one side thereof to the other, and operating means is provided for closing the valve means and moving the piston past the inlet port to a position wherein hydraulic fluid flows through the inlet port into the cylinder on only one side of the piston. The normally open valve means includes an elongated valve sleeve slidably mounted in a piston bore having an enlarged intermediate portion defining a cavity surrounding the sleeve member. The sleeve member has a large external area within the cavity facing in one direction than in the other direction, and a leakage path is provided for communication of the cavity with the cylinder on one side of the piston. Pressurization of the cavity causes fluid pressure to act on the larger external area of the sleeve member for biasing same in one direction with a force proportional to the pressure acting on the piston.

Hydraulic booster

A hydraulic servo valve assembly and a control system therefor employing a pneumatic sensor-actuator are disclosed. The servo valve assembly comprises a servo-operated power valve assembly including a differential piston, a solenoid operated override and hysteresis adjustment. The valve assembly is a 'snap-action' device wherein the power valve differential piston is selectively positioned through use of the pneumatic sensor controlled servo valve to vent the pressure applied to the larger area reaction surface of the piston.

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Chesaning, MI, United States of America

Roger C Popp