Abstract: A circuit for use with an apparatus such as a tractor having an output device such as a mower deck or snow thrower, comprising a user operated switch and a position sensing switch to detect the rotational direction of a shaft such as an output axle, so that the operational status of the output device may be changed depending on the rotational direction of the shaft.

Abstract: A method for use with an apparatus such as a tractor having an engine and an output device, such as a mower deck or snow thrower, comprising the steps of determining a rotational direction of a rotatable shaft as one of a forward direction and a reverse direction and selecting the operational status of the output device as one of an engaged state and a disengaged state, where the operational status is in the disengaged state when the shaft rotates in the reverse direction and is in the engaged state when the shaft does not rotate in the reverse direction.

Abstract: In a hydrostatic transmission or integrated hydrostatic transaxle having a housing forming an oil sump and a hydraulic pump and hydraulic motor mounted in the sump and connected through hydraulic porting, a filter housing or other structure defining an internal volume is mounted adjacent to the check valves for the hydraulic porting. Oil passing into this internal volume is filtered to prevent the introduction of contaminants into the hydraulic porting. A himney is formed as part of the filter housing and extends upwards therefrom, and is open to the internal volume. The chimney also includes an opening to permit air to escape to the oil sump, to reduce the risk of air being introduced into the hydraulic porting through the check valves.

Abstract: A combination wheel retainer and axle shaft cover. The combination wheel retainer and axle shaft cover includes a retaining ring portion sized and arranged to mate with an axle shaft, a cover portion sized and arranged to generally overlay an end of the axle shaft, and a joining portion for connecting the retaining ring portion to the cover portion.

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 vent apparatus for a hydrostatic device such as a hydrostatic transmission, including a vent tube in communication with a reservoir and a vent cap secured to the tube in a manner to permit the cap to pivot or swivel with respect to the vent tube, in order to prevent water from entering the reservoir through the vent tube.

Abstract: A bypass mechanism is provided for use in a hydrostatic transmission, to enable the user to open or close a valve between the two pressure sides of the hydraulic circuit of the transmission. An electrical mechanism is positioned to open or close the valve based on a signal which may be generated by a switch associated with the hydrostatic transmission.

Abstract: A dual tandem pump apparatus having a pair of coaxially arranged pump shafts and a separate input shaft that is not coaxial with the pump shafts. Charge pumps may be mounted on end caps secured to the housing or may be driven directly by the input shaft. A coupler or bevel gear arrangement is used inside the pump housing to drive the pump shafts from the input shaft.

Abstract: A vent apparatus for an enclosed space such as that within a structure or a vehicle, including a vent tube having a first end that extends outside of the closed space and a second end that is connected to the enclosed space and a vent cap removably coupled to the vent tube and capable of pivoting or swiveling with respect to the vent tube to prevent water from entering the reservoir through the vent tube.

Abstract: In a hydrostatic transmission or integrated hydrostatic transaxle having a housing forming an oil sump and a hydraulic pump and hydraulic motor mounted in the sump and connected through hydraulic porting, a filter housing or other structure defining an internal volume is mounted adjacent to the check valves for the hydraulic porting. Oil passing into this internal volume is filtered to prevent the introduction of contaminants into the hydraulic porting. A chimney is formed as part of the filter housing and extends upwards therefrom, and is open to the internal volume. The chimney also includes an opening to permit air to escape to the oil sump, to reduce the risk of air being introduced into the hydraulic porting through the check valves.

Abstract: A dual pump apparatus for use on a vehicle or industrial application having a housing in which a pair of hydraulic pumps are mounted, having by at least one charge pump mounted on an end cap, and the trunnion arms for controlling the hydraulic pumps extending out of opposite sides of the housing. A cooling fan may be mounted on the primary or secondary input shaft on the opposite side of the pulley used to engage the prime mover. An auxiliary pump may also be mounted on the primary input shaft and may be located either at the input end thereof adjacent to the pulley, or on the opposite side of the housing.

Abstract: A hydrostatic transmission mountable to a vehicle frame. The hydrostatic transmission is adapted to removeably receive an axle shaft. The hydrostatic transmission is also adapted to be mounted to at least one of two opposed side members of the vehicle frame. The opposed side members have openings though which the axle shaft passes. The vehicle may be a snow thrower.

Abstract: A method for providing a bypass for a hydraulic circuit in a hydrostatic transmission enables the user to open or close a bypass between the hydraulic circuit of the transmission and a hydraulic fluid sump. The method uses an electromechanical valve mechanism, and provides an electrical signal thereto to open the bypass and divert the hydraulic fluid from the circuit to the sump.

Abstract: A hydrostatic transmission design incorporating a unique housing shape and configuration, including a vertical split of the two casing elements, which are shaped to conform to the internal components of the transmission. The center section of the transmission has a unique configuration including a trunnion mounted swash plate, means for mounting the center section to the transmission and a motor output shaft mounted below the pump running surface. The transmission also includes an expansion chamber, preferably secured externally to the sump, having a tube mounted therein to transfer hydraulic fluid between the chamber and the sump.

Abstract: A bypass mechanism is provided for use in a hydrostatic transmission, to enable the user to open or close a bypass between the hydraulic circuit of the transmission and a sump. The invention also comprises a safety mechanism to prevent excessive freewheeling of the vehicle by providing a plate or other bypass mechanism which engages a valve. The plate or other mechanism is moveable between a first position where the valve opens the hydraulic circuit to the sump and a second position where the valve closes the hydraulic circuit, and a spring mechanism enables the valve to override the bypass mechanism and force the circuit closed under excessive pressure.

Abstract: A hydrostatic transmission design incorporating a unique housing shape and configuration, including a vertical split of the two casing elements, which are shaped to conform to the internal components of the transmission. The center section of the transmission has a unique configuration including a trunnion mounted swash plate, means for mounting the center section to the transmission and a motor output shaft mounted below the pump running surface. The transmission also includes an expansion chamber, preferably secured externally to the sump, having a tube mounted therein to transfer hydraulic fluid between the chamber and the sump.

Abstract: An electromechanical bypass mechanism is provided for use in a hydrostatic transmission, to enable the user to open or close a bypass to the hydraulic circuit of the transmission through use of an switch mechanism attached to the bypass mechanism in the circuit. The invention also comprises an improved neutral feature for hydrostatic transmissions, with a switch connected to the control mechanism for the unit, whereby the switch is activated to place the unit in bypass when said mechanism is placed in the neutral location. A means is provided for opening and closing a shunt or bypass between the high pressure side and the low pressure side of the hydrostatic system which is triggered by an electrical signal.