Abstract: Prior art non-generated, tip-relieved spiral bevel gears had tip-relieved surfaces that were nonuniform from the toe to the heel thereof. The subject tip-relieved spiral bevel gear is adapted to be manufactured by a gear generating machine, and includes a plurality of modified gear teeth individually having a convex tooth face and a relatively uniform tip-relieved surface on the convex tooth face from the toe to the heel portion thereof essentially parallel to the face angle at the outer tip surface. A two-pass method of machining the modified gear teeth is described.

Abstract: Neutralizer valves are useful in hydraulic steering systems to hydraulically stop the steering motion. However the known neutralizer valve arrangements will not work in load sensing hydrostatic steering systems. The subject load sensing hydrostatic steering system has a limit valve disposed in a load pressure signal signal line to normally communicate a load pressure siganl from a steering valve to a displacement controller of a load sensing variable displacement pump so that the displacement of the pump is regulated to meet the demand for pressurized fluid by the steering valve. When a pair of vehicle members reach a preselected position during a steering maneuver, the limit valve is moved to a position interrupting communication of the load pressure signal to the displacement controller causing the pump to destroke to its minimum output thereby stopping the flow of pressurized fluid to the steering valve and to a pair of steering cylinders.

Abstract: Pressure compensated hydraulic systems are useful in reducing the expenditure of energy when the system is in operation but not being used. Optimizing the operating characteristics for certain applications increases the response time due to no load pressure or cavitation in the hydraulic jack being actuated. The pressure compensated hydraulic system includes a restriction disposed in a pilot passage which normally subjects pump discharge pressure to one end of an unloading valve. A control passage is connected to the pilot passage between the restriction and the end of the unloading valve and in one mode of operation communicates pressurized fluid through the system and eventually back to the spring end of the unloading valve to move it to a fluid blocking position.

Abstract: Load sensing hydraulic systems are useful for distributing fluid from a variable displacement pump to the individual work circuits in accordance with the demand of each work circuit. Preventing load pressure from being drained from the motors of the work circuits during some operating functions heretofore required the use of a pair of pressure compensating valves and a pair of shuttle valves at each of the directional control valves. The subject load pressure duplicating circuit includes a single load pressure duplicating valve having an end subjected to the load pressure in a signal network and reduces pump pressure entering the valve to a pressure level at the output thereof equal to the load pressure. This duplicated pressure is then utilized as the control fluid for the pressure compensating valves and a displacement controller of the pump. The system is greatly simplified by the use of only a single duplicating valve for a hydraulic system having a plurality of work circuits.

Abstract: Pressure compensating valves located downstream of the directional control valves are useful in providing load independent, proportional flow control hydraulic systems and normally serve as load checks. The subject load check and pressure compensating valve is designed for use in a hydraulic system in which the pressure of a common pressure signal directed to all the pressure compensating valves of the system is limited to a predetermined maximum level. The pressure compensating valve includes a valve element disposed downstream of a metering orifice, a separate load piston disposed in end-to-end relationship with the valve element in a common bore and a pressure compensating spring disposed in a chamber behind the load piston and biasing the load piston and valve element to the load check position.

Abstract: An electrical transmission control mechanism includes a first printed circuit board having a first plurality of contact elements thereon, and a second printed circuit board connected thereto and having a second plurality of contact elements thereon. A transmission control assembly includes a control member movable laterally and adapted to cause travel of a holder and a first plurality of wiper members linearly across the first plurality of contact elements for selecting the direction of rotation of a transmission, and movable longitudinally and adapted to cause rotation of a second holder and a second plurality of wiper members across the second plurality of contact elements. A third printed circuit board is preferably mounted in parallel relation to the second printed circuit board and at a right angle to the first printed circuit board when a substantial number of gear ratios are used.

Abstract: Hydraulic hammers are normally controlled by an actuating valve which controls the flow of fluid from a source of pressurized fluid to the hydraulic hammer. During certain periods of operation, the actuating valve totally blocks communication of fluid to the hydraulic hammer, thereby causing the fluid from the source of pressurized fluid to be expelled through a relief valve. The subject hydraulic hammer and control arrangement therefor includes an accumulator for storing the pressurized fluid from the source of pressurized fluid during periods of fluid blockage by the actuating valve and for supplementing the flow of fluid from the source of pressurized fluid when the actuating valve is communicating pressurized fluid to the hydraulic hammer. This increases the overall efficiency thereof.

Abstract: The use of a pair of small variable displacement hydraulic pumps in a hydraulic system offers some advantages. The output of the two pumps of the known systems is normally not combined, but is selectively combined under a majority of the operating conditions. The subject load sensing hydraulic control system has first and second hydraulic circuits with each circuit having a plurality of pilot operated control valves operatively connected to a variable displacement pump. The output flow of both pumps is normally made available to both hydraulic circuits through a combiner valve so that the output capability of both pumps can be used to satisfy the demand for fluid by a single control valve or by one or more of the control valves from each circuit. A valve arrangement connects the highest load pressure of the control system to both pumps when the output flow thereof is being combined.

Abstract: Pilot control circuits are useful, for example, for controlling the actuation of main control valves of load sensing hydraulic systems. Using the main supply pump as the source of pressurized pilot fluid sometimes results in inadequate pilot pressure for maintaining the main control valves in an actuated position under some operating conditions. The subject pilot control system includes an accumulator to store pressurized fluid received from the main supply pump for use by the pilot control circuit when the pressure level of the main hydraulic system momentarily drops below a level for proper pilot control operation. Thus, the main control valves are maintained in their actuated position irregardless of the pressure level of the fluid in the main supply system.

Abstract: Ignition system wiring harnesses are used to carry discrete electrical signals to the fuel igniter devices of spark ignited engines. Externally mounted wiring harnesses are subjected to damage which can cause the engine to run inefficiently. The subject ignition system wiring harness extends through internal passageways in an engine block and a plurality of cylinder heads mounted thereon. The wiring harness is retained at fixed locations by a plurality of spring clip retainers, each of which has a normally flat elongate spring clip deflected around the wiring harness and slidably extending through a pair of slots in a bracket. The spring clip exerts a nearly constant force on the wiring harness as it tries to straighten to its normally flat condition regardless of the cross sectional size of the wiring harness. Thus, one size of spring clip retainer can be used for various sizes of wiring harness.

Abstract: Prior art non-generated, tip-relieved spiral bevel gears had tip-relieved surfaces that were nonuniform from the toe to the heel thereof. The subject tip-relieved spiral bevel gear is adapted to be manufactured by a gear generating machine, and includes a plurality of modified gear teeth individually having a convex tooth face and a relatively uniform tip-relieved surface on the convex tooth face from the toe to the heel portion thereof substantially parallel to the face angle at the outer tip surface. A two-pass method of machining the modified gear teeth is described.

Abstract: Large earthmoving vehicles require complex mechanisms for mechanically driving the auxiliary power units. The subject drive mechanism includes an elevating transfer gear train at the rear frame portion of the vehicle that drives a rear auxiliary power unit via an upper transfer gear, and that drives a front auxiliary power unit on the front frame portion of the vehicle through a relatively long drive shaft system extending from the upper transfer gear. A torsionally tuned spring coupling having a plurality of compression spring sets arranged in at least two circular arrays is incorporated between the engine and an input gear of the transfer gear train for providing two stiffness rates and effectively isolating the drive mechanism from the torsional excitation pulses of the engine and the effects of gear shifting of an associated transmission for powerably driving the vehicle.

Abstract: A vehicular steering and transmission shifting control mechanism includes a transversally rockable control handle and a steering actuator element connected at the bottom thereof to selectively depress either a left or right actuating plunger of a hydraulic pilot valve assembly for effecting steering. The control handle is contoured to be easily grasped and to position an electrical switch actuating element for comfortable movement by an operator's thumb to change the speed of a multi-speed transmission through an associated electronic transmission control system. A three-way electrical switch actuating element at the front of the control handle is adapted to be rocked to select one of forward, neutral, and reverse modes of the transmission.

Abstract: Cushioned swing circuits sometimes have a restricted passage between the motor conduits to allow the implement controlled by the swing circuit to coast to a stop. However, opening and closing of the restricted passage was manually controlled, thereby requiring an additional manipulative step by the operator. The present cushioned swing circuit includes a cushion valve moveable to an open position to establish communication through vent line means when a pressure differential greater than a predetermined level is generated in one of the motor conduits connecting a directional control valve to a hydraulic motor. The cushion valve is retained in the open position for a predetermined limited time after the pressure differential drops below the predetermined level so that the inertia generated pressure in the circuit is dissipated through the vent line means.

Abstract: Quick drop valves are usable in hydraulic circuits in which fluid is expelled from a hydraulic cylinder due to gravity force acting on a load connected to the hydraulic cylinder. The present quick drop valve has a sleeve carried by a valve member for establishing an orifice through which the fluid expelled from the hydraulic cylinder passes. When the flow rate of the expelled fluid exceeds a predetermined flow rate, a differential pressure generated by the orifice causes the valve member to start moving toward a quick drop position. In so doing, the sleeve quickly establishes a more restrictive orifice to immediately generate a higher differential pressure to cause the valve member to quickly move to the quick drop position. The more restrictive orifice also causes a greater amount of the expelled fluid to be returned by the valve member to the expanding ends of the hydraulic cylinders, yet still allows sufficient flow therethrough so that the quick drop action can be stopped if so desired.

Abstract: Reversible, variable displacement, hydraulic devices are useful in transmitting power from an engine to a driven device. The hydraulic components of such devices are generally quite bulky and difficulty to center to swash plate thereof. The subject device includes a pair of servo valves adjustably disposed within a case for individually controlling the flow of actuating fluid to and from a pair of hydraulic servo actuators. A servo feedback mechanism is provided to mechanically move a valve spool of one of the servo valves to a position for exhausting fluid from one of the servo actuators as the spool of the other servo valve is moved to a position for directing actuating fluid to the other of the servo actuators. The feedback mechanism also moves the spools substantially to their neutral position when a swash plate controlled by the servo actuators reaches a desired angular position after the other spool is first moved to the position for directing actuating fluid to the other servo actuator.

Abstract: Load sensing hydraulic systems conserve energy by generating only the fluid flow demanded by the system and at a pressure only slightly greater than the highest load pressure of the system. Optimizing the operating characteristics of the system for certain applications also caused the variable displacement pump to go to its maximum displacement setting with the excess fluid generated thereby not doing any useful work. The load sensing hydraulic system includes a flow control valve connected to a directional control valve and has an operating position in which fluid exhausted from a hydraulic jack is transmitted therethrough to a tank. A signal valve is disposed in a control pressure signal line for controlling fluid flow therethrough from a supply conduit to one end of the flow control valve. When the signal valve is blocking fluid flow through the signal line, the flow control valve is in the above-noted operating position.

Abstract: Flow amplified control systems are useful in pilot operated steering systems. The load responsive flow amplified control system includes a directional control valve movable to an operating position to direct fluid from the operating fluid circuit through a variable orifice to a steering motor and to direct control fluid from a control fluid circuit through another variable orifice to be combined with the fluid going to the steering motor. The operating fluid circuit and the control fluid circuit are provided with fluid from a common variable displacement pump. The directional control valve is moved to an operating position by the control fluid acting thereon and is pressure compensated insofar as the flow of control fluid passing through the another variable orifice such that a substantially constant predetermined pressure differential exists across the another variable orifice.

Abstract: Impact rippers are useful in fracturing rocks, concrete, etc. which cannot be fractured by ripping alone. Operating the impactor of the impact ripper without sufficient loading applied to the ripper tip is detrimental to the life of the impact ripper. The subject control system includes a pilot operated selector valve which blocks pressurized fluid from the impactor in the absence of pilot fluid thereto and is shifted by pressurized pilot fluid to a position to direct pressurized fluid to the impactor. A pressure switch is rendered conductive when the fluid pressure generated in a hydraulic cylinder exceeds a predetermined value due to loading on the ripper tip. This actuates a solenoid valve to direct pressurized pilot fluid to the selector valve. Thus the impactor is activated only when the loading on the ripper tip is above a preselected threshold and is automatically deactivated when the loading on the ripper tip drops below the preselected threshold.

Abstract: Hydraulic recoil mechanisms are useful, for example, in maintaining desired tension in the drive belts of vehicles. The hydraulic components of such mechanisms are prone to leakage over an extended period of frictionally driven belted non-usage and thereby allow the tension in the belts to gradually decrease. The subject belt tension control system includes a friction locking device to automatically lock the piston rod relative to the cylinder to maintain a predetermined level of tension in the belt when the pump which furnishes pressurized hydraulic fluid to the system stops operating. Thus, the frictional couple between the belt and the drive wheel is maintained during periods of non-use and the parking brake is effective to hold the vehicle at a stationary position.