Abstract: A viscous fan clutch is typically employed in a fan drive mechanism within a truck or automobile. A shaft, driven by the engine, rotates a clutch member within the fan drive. The clutch member is arranged for fluid engagement with a body member for the transmission of torque thereto when fluid is disposed in an operating chamber defined by complimentary shear surfaces in the clutch and body members. During relative rotation between the two members, fluid is pumped through a return passage to a valve coaxially disposed with the driven shaft which selectively directs a flow of viscous fluid alternately to a storage chamber or directly back into the operating chamber. The valve is biased into a first position in which the fluid is directed into a fluid storage chamber and is actuated into the second position by means of a coaxially disposed solenoid acting upon ferrous metal members of the valve.

Abstract: A low pressure drop air flowmeter for an automobile engine is disclosed. The meter contains a main air flow passage, a relatively small venturi to receive a portion of the air flow, pressure ports for sensing stagnation and static pressure and a set of swirl vanes disposed adjacent the outlet of the venturi and operative to impart a swirl to the remainder of the air in the main passage, thereby creating a reduced pressure at the venturi outlet for amplifying the pressure difference between the stagnation and static pressure without appreciably increasing the pressure drop across the flowmeter. A tertiary passage provides a path of fluid communication between points upstream and downstream of the swirl vanes. This passage can be selectively opened or restricted by a valve which, in the preferred embodiment of the invention, opens the tertiary passage with increasing overall flow rate.

Abstract: Tire pressure monitors are incorporated in vehicles having pneumatic tires to continuously or periodically measure the air pressure in the tires and to alert the driver should the pressure in one of the tires fall below a predetermined value. A self-contained generator-transmitter unit is affixed to each wheel, each unit monitoring the air pressure in the tire associated therewith and generating an RF signal when the pressure falls below a predetermined value. A receiver, located in the passenger compartment of the vehicle, receives the signal(s) from the generator-transmitter units to indicate a low tire condition to the vehicle operator. The generators operate only during rotation of the wheels which effect relative rotation between two members in each generator, one member carrying a permanent magnet and the other carrying an inductor.

Abstract: A crane operating aid comprises a load moment computer and a number of transducers which monitor crane parameters such as boom length, boom angle, and boom reaction forces. The computer then calculates the percentage of load capacity as a function of the crane manufacturer's published load rating tables. In cranes having booms which are luffed by a plurality of hydraulic lift rams, boom reaction forces are determined by providing separate pressure transducers on the lower or high pressure end of each ram. The upper or low pressure ends of the rams are in fluid communication with one another, requiring only a single pressure transducer. Each transducer generates an output signal as a function of the pressure which it is monitoring. The signals from the transducers associated with the high pressure ends of the rams are averaged and the difference between the output signal of the transducer associated with the low pressure ends of the rams and the average signal is used to generate a reaction force signal.

Abstract: A regenerative hydraulic system includes a control circuit having a pressure sensing valve therein. The valve is in fluid communication with a pump and a work cylinder causing the cylinder to be actuated at a relatively high velocity during a first increment of displacement by employing regenerative techniques which interconnect the head and rod sides of the cylinder. Pressure increases due to encountering a load are monitored, and at a predetermined value, the system switches to a non-regenerative mode in which the effective force exerted by the cylinder is substantially increased. Upon switching to the non-regenerative mode, the system is latched and will remain so until the system fluid pressure drops to a second predetermined value which is substantially smaller than the first pressure, resulting in a hysteretic control characteristic which will prevent an unstable condition. A dual rate spring is included within the valve urging it into the regenerative position.

Abstract: A crane operating aid comprises a load moment computer and a number of sensors which monitor crane parameters, such as boom length, boom angle, slewing angle, and boom reaction forces. The computer then calculates the percentage of load capacity as a function of the crane manufacturer's published load rating tables. Absolute encoding digital optical sensors are employed to monitor linear or angular displacement between portions of the crane which are operatively moveable with respect to one another. The digital output signals from the various sensors are then fed to the computer for use in its calculations. Each sensor comprises a detector made up of a light emitting element which is spaced from a light receiving element and an encoder disc which is mounted for displacement with respect to the detector and operates to present a series of tracks intermediate the light emitting portion and light receiving portion of the detector. Each track comprises a series of alternatingly opaque and transparent portions.

Abstract: A temperature responsive clutch has a first arcuate inward facing clutch member, which can be a housing, secured to a rotating shaft. A second arcuate outward facing clutch member is mounted on the shaft radially inward from the first member and rotates independent of the first member. At least a portion of the second clutch member is adapted to move into and out of engagement with the first member. In the engaged position, the first and second members rotate in unison to rotate a fan attached to the second member. A temperature responsive device, such as a wax pill motor, is located so air passes thereover. The temperature responsive device will move a portion of one of said members radially into engagement with the other member when the temperature of the passing air signals that additional cooling is needed.