Abstract: A hydraulic drive device including a hydraulic pump and hydraulic motor disposed in a casing and driving an axle having an interior end disposed inside the casing and abutting against an interior surface of the casing to prevent an inward axial movement of the axle shaft. The device further includes an expansion chamber formed in the casing by a plate having a generally flat portion extending generally perpendicular to the plate to form a thumb stop and an indentation sized to accept a human finger to assist during installation of the plate.

Abstract: The present invention relates to a dual antenna coil identification system, and more particularly, to an interrogator or reader for inductively coupling to a transponder and thereby extract data from the transponder. The magnetic field required to energize a transponder is generated by currents flowing through two essentially identical but opposite phased antenna coils arranged near the area where tags are to be read.

Abstract: An improved valve for use in a hydrostatic drive apparatus for a vehicle such as a zero turn vehicle. For each hydraulic drive system in the vehicle, a valve is located between the high and low pressure sides of the closed hydraulic circuit connecting the hydraulic pump and motor. The valve opens when the pressure rise rate in the high pressure side reaches a set level to minimize pressure spikes in the high pressure side and thus improve performance of the vehicle. A valve block may be used to mount the valve, and a second valve may also be included therein to connect the two pressure sides of the hydraulic circuit in a similar manner when the vehicle is operated in reverse.

Abstract: An improved valve for use in a hydrostatic drive apparatus for a vehicle such as a zero turn vehicle. For each hydraulic drive system in the vehicle, a valve is located between the high and low pressure sides of the closed hydraulic circuit connecting the hydraulic pump and motor. The valve opens when the pressure rise rate in the high pressure side reaches a set level to minimize pressure spikes in the high pressure side and thus improve performance of the vehicle. A valve block may be used to mount the valve, and a second valve may also be included therein to connect the two pressure sides of the hydraulic circuit in a similar manner when the vehicle is operated in reverse.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: An expansion chamber for a hydrostatic transaxle to provide for expansion of the hydraulic oil during operation of the transaxle, where the expansion chamber is formed as part of the housing inside the main sump by ribs or other members extending from the housing and is closed by a cap to form a sealed chamber. A siphon tube may be secured to the cap or integrally formed therein, or formed by additional cast ribs or similar features formed into the housing and also sealed by the cap.

Abstract: A pair of zero-turn, hydrostatic transaxles (HZTs) that may be joined to form an integrated, zero-turn, hydrostatic transaxle. Each of the hydrostatic transaxles are further comprised of a casing carrying a hydraulic pump driven by an input shaft, a hydraulic motor driven by a the hydraulic pump through porting contained within a center section, and an axle shaft driven by the hydraulic motor. The hydrostatic transaxles are joined along an interface extending generally perpendicularly to the axle shafts.

Abstract: An improved valve for use in a hydrostatic drive apparatus for a vehicle such as a zero turn vehicle. For each hydraulic drive system in the vehicle, a valve is located between the high and low pressure sides of the closed hydraulic circuit connecting the hydraulic pump and motor. The valve opens when the pressure rise rate in the high pressure side reaches a set level to minimize pressure spikes in the high pressure side and thus improve performance of the vehicle. A valve block may be used to mount the valve, and a second valve may also be included therein to connect the two pressure sides of the hydraulic circuit in a similar manner when the vehicle is operated in reverse.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: An improved valve for use in a hydrostatic drive apparatus for a vehicle such as a zero turn vehicle. For each hydraulic drive system in the vehicle, a valve is located between the high and low pressure sides of the closed hydraulic circuit connecting the hydraulic pump and motor. The valve opens when the pressure rise rate in the high pressure side reaches a set level to minimize pressure spikes in the high pressure side and thus improve performance of the vehicle. A valve block may be used to mount the valve, and a second valve may also be included therein to connect the two pressure sides of the hydraulic circuit in a similar manner when the vehicle is operated in reverse.

Abstract: An expansion chamber for a hydrostatic transaxle to provide for expansion of the hydraulic oil during operation of the transaxle, where the expansion chamber is formed as part of the housing inside the main sump by ribs or other members extending from the housing and is closed by a cap to form a sealed chamber. A siphon tube may be secured to the cap or integrally formed therein, or formed by additional cast ribs or similar features formed into the housing and also sealed by the cap.

Abstract: A method of assembling a tandem pump comprising first and second pumps connected in tandem by an interface. Each pump has a housing and an end cap containing hydraulic porting. The interface connects the end cap of one pump to the housing of the other pump.

Abstract: A pair of substantially mirror image, zero-turn, hydrostatic transaxles (HZTs) that may be joined to form an integrated, zero-turn, hydrostatic transaxle. The control arm and brake mechanism associated with the HZTs can be mounted on either the inboard or outboard side of the HZT casing. In one embodiment, an integrated, inboard brake mechanism is provided for the joined HZTs.

Abstract: A tandem pump comprising first and second pumps connected in tandem by an interface. Each pump has a housing and an end cap containing hydraulic porting. The interface connects the end cap of one pump to the housing of the other pump.

Abstract: A tandem pump comprising first and second pumps connected by an interface. An interface for connecting an end cap of a first pump to a housing of a second pump. An interface kit for connecting two pumps in axial alignment to form a tandem pump.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: A control device for hydrostatic apparatus is disclosed. One embodiment in the control device is optimized for use with a hydrostatic transmission having a casing. The control arm is movably mounted to the casing and frictional structure engages the control arm to resist rotational movement of the control arm. A spring may be used to bias a wedge into frictional relation with the control arm to resist rotation of the control arm. The wedge may also be secured with removable attachments.

Abstract: Improvements are described in the injection of ammonia (NH.sub.3) into the exhaust gases of an engine to reduce nitrogen oxides. Instead of merely injecting ammonia into the exhaust gas conduit through a hole in its side, an ammonia injector (90) is provided that projects considerably into the exhaust conduit (16), with the injector having a plurality of holes (94). The ammonia is activated to decompose it into its reactive components, including NH.sub.2 and NH prior to injecting it into the exhaust conduit. Such activation prior to injection can be accomplished by heating the ammonia in the presence of a catalyst such as a metal of the platinum group, iron, nickel, or zinc. In an engine that has a fuel injection system wherein electrical pulses are delivered to fuel injectors to control the fuel flow rate, the durations of these electrical signals are used to control the opening of a valve (72) that controls the flow rate of ammonia into the exhaust gas conduit.

Abstract: An anchoring device for use on the shaft of a beach umbrella or the like, including a conical member that tapers to a rounded point and around which is spirally wound a constant pitch asymmetric buttress-type thread whose upper surface is perpendicular to the long axis of the conical member.