Abstract: A connector has a tubular body with first and second insulating bodies held therein. The first body is at the front, exposed end of the connector and has electrically conductive components for receiving the blades of a plug. The rear of the first body and the front of the second body have axially extending switch contacts which are brought into contact by rotation of the first body. Rotation is prevented by a locking ring nonrotatably coupled to the first body and engaging lugs at the front end of the connector. The locking ring is released from the lugs by axial force supplied by full insertion of the plug.

Abstract: An explosion proof electrical enclosure has a relieved joining flange at the junction between the cover and the body of the enclosure. The relieved portion provides an area reducing the bolt load in the event the enclosure is subjected to an internal explosion. As a result, fewer bolts may be used to join the enclosure, reducing the cost of the enclosure, increasing the convenience of access to the enclosure and reducing the labor required to remove or install the cover. The cover of the enclosure has increased stiffening structure at the corners so that the bolts in the corners of the enclosure may be eliminated.

Abstract: The invention relates to an improvement in a valve for a tractor air brake system for changing the pressure delivered to air brakes on a tractor rear axle during "bob tail" operation and particularly to a valve wherein the ratio is changed by communication of control pressure to a second control surface in accordance with the presence of trailer emergency pressure. The improved ratio control valve enables fluid pressure communication to both control surfaces of the ratio valve until a predetermined input pressure is reached so that the "crack-open" input pressure for both the "trailer-connected" and the "bob tail" modes of operation will be the same. Further in accordance with the invention, a blend-back valve is provided which is biased by the available fluid pressure in the tractor reservoir tank so that the maximum available tractor reservoir pressure may always be applied to the tractor rear axle brakes even when the trailer is operating in the "bob tail" mode.

Abstract: A master cylinder assembly includes a body in which fluid pressure is developed. A fluid reservoir is detachably attached to the sides of the body. Fluid communication between the fluid reservoir and the body is provided through one of the sides of the body.

Abstract: A pressure control valve for use in vehicle hydraulic diagonal split brake systems. The valve includes two valve pistons which operate to limit the fluid pressure delivered to the rear wheel brakes relative to that delivered to the front wheel brakes. The valve also includes a failure warning mechanism having a switch actuating piston. In the event of a failure in one branch of the diagonal split brake system, the switch actuating piston operates to simultaneously preclude the two valve pistons from limiting the rear wheel brake pressure so that the rear wheel brake in the unfailed branch of the brake system can develop the maximum braking effort for vehicle emergency braking.

Abstract: A valve for use in vehicle hydraulic brake systems for the purpose of limiting the rear wheel brake pressure relative to the front wheel brake pressure in order to reduce the potential for premature rear wheel lock. The valve includes a proportioning piston which operates to limit the fluid pressure delivered to the rear wheel brakes and an inertia member which senses changes in vehicle loading. When a vehicle is fully loaded, the inertia member remains in a position where it will disable the proportioning piston in its open position and, consequently, the rear wheel brake pressure will be equal to the front wheel brake pressure. When the same vehicle is unloaded, the inertia member moves in response to deceleration to a position where it will not disable the proportioning piston in its open position so that the rear wheel brake pressure will be reduced relative to the front wheel brake pressure.

Abstract: A valve for use in vehicle hydraulic brake systems for the purpose of limiting the rear wheel brake pressure relative to the front wheel brake pressure in order to reduce the potential for premature rear wheel lock. The valve includes a proportioning piston which operates to limit the fluid pressure delivered to the rear wheel brakes and an inertia member which senses changes in vehicle loading. When a vehicle is fully loaded, the inertia member remains in a position where it will disable the proportioning piston in its open position and, consequently, the rear wheel brake pressure will be equal to the front wheel brake pressure. When the same vehicle is unloaded, the inertia member moves in response to deceleration to a position where it will not disable the proportioning piston so that the rear wheel brake pressure will be reduced relative to the front wheel brake pressure.

Abstract: An auxiliary compensating piston in a tandem automotive master cylinder containing two pressure pistons closes relief port holes between the cylinder and brake fluid reservoirs. A compensating valve feeds replacement fluid into the cylinder during brake release. The auxiliary compensating piston opens the relief port holes at the end of brake release to relieve excess brake fluid from the cylinder.

Abstract: An air-actuated disc brake develops the required force magnification to operate disc brakes from an air pressure chamber using push-pull rods driving a pair of cam levers applying normal force to one shoe plate of the disc brake. Clamp action is carried through to an opposing brake shoe plate by a caliper. The entire air applied disc brake is mounted as a unit to the axle flange. An automatic adjuster compensates for brake lining wear. The cam levers are pivotally mounted to a movable cam carrier located between the caliper and one brake shoe plate.

Abstract: A brake master cylinder contains a primary and a secondary piston each having an associated brake fluid reservoir and compensator valve. Normally, the primary piston is actuated directly by mechanical force and the secondary piston is actuated by fluid pressure acting on it from the primary cylinder. If brake fluid pressure fails in either primary or secondary piston regions, the unfailed piston thereupon responds directly to mechanical actuating forces to produce normal brake fluid pressure in its associated wheel cylinders without interference from the failed piston.Compensator valves, external to the cylinders enable brake fluid replenishment without requiring additional cylinder length.

Abstract: A tandem brake master cylinder has a proportioning valve between two pressure regions therein. The pressure in a second pressure region changes by a proportion of the change in a first pressure region at least over a part of the pressure range of the first pressure region.

Abstract: An air-actuated disc brake develops the required force magnification to operate disc brakes from an air pressure chamber using push-pull rods driving a pair of cam levers applying normal force to one shoe plate of the disc brake. Clamp action is carried through to an opposing brake shoe plate by a caliper. The entire air applied disc brake is mounted as a unit to the axle flange. An automatic adjuster compensates for brake lining wear.

Abstract: An air-actuated disc brake develops the required force magnification to operate disc brakes from an air pressure chamber using push-pull rods driving a pair of cam levers applying normal force to one shoe plate of the disc brake. Clamp action is carried through to an opposing brake shoe plate by a caliper. The entire air applied disc brake is mounted as a unit to the axle flange. An automatic adjuster compensates for brake lining wear.

Abstract: A brake pressure distribution valve distributes fluid pressure to front brakes in proportion to fluid pressure distributed to rear brakes, and in addition, "holds off" the pressure distribution to the front brakes for delayed distribution thereto. The valve includes a housing having a cavity formed therein. Inlet and outlet ports permit fluid to flow into and out of the cavity. A first piston engages a metering seal to normally close one fluid passage and to cut off fluid communication between inlet and outlet ports. Another fluid passage is normally open to establish fluid communication between the inlet and outlet ports. Due to a fluid pressure buildup, a closing member is actuated to close the other passage thus holding off pressure distribution to the front brakes. As the fluid pressure buildup continues the one passage opens to re-establish fluid communication between the inlet and outlet ports.

Abstract: In a hydraulic brake system, a housing includes a brake master cylinder and a reservoir formed therein for containing a supply of brake fluid. A sensor piston in contact with the pressure in the brake master cylinder is connected to an indicator piston. The indicator piston is coaxial with a blind cylindrical indicator bore. The blind bore and indicator piston are in communication with the reservoir at a level below which the brake fluid should not be allowed to recede. When the brake is operated, brake master cylinder pressure urges the sensor piston outward. The connected indicator piston is urged toward the blind bore. If the reservoir contains fluid, the blind bore is filled with the fluid. Fluid lock of the indicator piston therefore occurs before any appreciable indicator piston motion into the blind indicator bore. On the other hand, if the reservoir, and the communicating indicator bore, are empty, the indicator piston is enabled to enter the indicator bore by compressing air therein.

Abstract: A brake pressure distribution valve includes a housing having a cavity formed therein. First and second pistons are movably mounted in the housing, each being resiliently urged in opposite directions. The second piston is mounted on the first piston for relative movement therewith. A retainer on the first piston can engage the second piston for unitary movement of both pistons. A first seal is provided to sealingly separate a first atmospheric portion at one end of the cavity from a pressurized fluid portion of the cavity. A second seal is provided to sealingly separate a second atmospheric portion at the other end of the cavity, opposite the one end, from the pressurized fluid portion. Ports in the housing permit pressurized fluid into and out of the pressurized fluid portion of the cavity. A passage may be provided axially through the first piston to interconnect the first and second atmospheric portions of the cavity.