Dwight L Stephenson, Age 54692 Crowe Rd, Columbus, MS 39702

6397655, Jun 4, 2002

Apr 3, 2000

09/541813

Dwight Stephenson - Delafield WI

Husco International, Inc. - Waukesha WI

G01L 2700

73 172, 73168

Operation of an electrically operated valve is calibrated by applying a gradually increasing electric current to the valve. While that is occurring pressure at either the inlet or outlet of the valve is measured to detect when the valve opens. When the valve opens the level of the electric current then being applied to the valve is employed to determine an initial current level to use subsequently whenever the valve is to be opened.

6398182, Jun 4, 2002

Aug 31, 2000

09/653601

Dwight B Stephenson - Delafield WI

HUSCO International, Inc. - Waukesha WI

F16K 3112

251 3003, 137489, 251 26, 251 27, 251 38

A discharge valve is provided to open an electrically controlled pilot valve in emergency situations such as during an electrical or hydraulic failure. The discharge valve has a poppet that operates in response to a pressurized control signal, which may be produced by a hand operated pump. When the poppet opens in response to the control signal, a path is established for fluid to flow from a control chamber of the pilot valve, thereby opening the latter valve.

6457487, Oct 1, 2002

May 2, 2001

09/847504

Dwight B. Stephenson - Delafield WI
Joseph Lawrence Pfaff - Wauwatosa WI

Husco International, Inc. - Waukesha WI

F15B 13043

13759616, 91447, 91448, 91459, 91464, 13759617

An assembly of a pair of electrically operated bidirectional proportional control valves and a four-way direction control valve governs the flow of fluid to and from a hydraulic cylinder. The four-way direction control valve alternately connects a pump supply line to one of a pair of intermediate conduits and a tank return line to the other intermediate conduit. That connection determines the direction of movement of the cylinder piston. The intermediate conduits are coupled to chambers of the cylinder by a separate one of the proportional control valves which meters the fluid flow to or from the respective chamber. Thus the proportional control valves control the rate of piston movement.

6467264, Oct 22, 2002

May 2, 2001

09/847834

Dwight B. Stephenson - Delafield WI
Joseph Lawrence Pfaff - Wauwatosa WI

Husco International, Inc. - Waukesha WI

F16D 3102

60460, 60368, 60494, 60484, 91454

A hydraulic system controls the flow of fluid to and from several functions on a machine. Each function has a valve assembly through which fluid is supplied under pressure from a source to an actuator and through which fluid returns from the actuator to a shared return line connected by a return line metering valve to the system tank. There are several regeneration modes of operation in which fluid exhausted from one port is supplied into the other port of the same actuator, which eliminates or reduces the amount of hydraulic fluid that must be supplied from the source. In some regeneration modes, input fluid for an actuator is obtained from another hydraulic function via the shared return line. In these regeneration modes an electronic controller operates the return line metering valve to restrict fluid from flowing into the tank from the shared return line, so that the fluid will be available to be supplied into an actuator port.

6502393, Jan 7, 2003

Sep 8, 2000

09/658842

Dwight B. Stephenson - Delafield WI
Randall S. Jackson - Burlington WI
Brian Clifton - Stockport, GB

Husco International, Inc. - Waukesha WI

F16D 3102

60414, 60424

A regeneration method for a hydraulic system enables the fluid being forced from a first actuator to be used to power a second actuator. Often the force of the load acting on a hydraulic actuator is used to move the actuator into a given position which motion forces fluid from the actuator. Rather than simply draining that fluid to the system tank, the fluid is routed to a second actuator to be powered when the pressure of the fluid draining at the first actuator is greater than the pressure required to power the second actuator. At other times the draining fluid can be used to drive the pump which has been configured to operate as a motor thereby driving the prime mover connected to the pump. Alternatively the draining fluid can be routed to an accumulator where it is stored under pressure until needed to power an actuator of the system. A unique bidirectional pilot operated poppet valve.

6647718, Nov 18, 2003

Oct 4, 2001

09/970761

Dwight B. Stephenson - Delafield WI

Husco International, Inc. - Waukesha WI

F15B 1122

60403, 91515, 414708

An industrial lift truck has a boom that is raised and lowered by a first hydraulic actuator and a load carrier that is pivoted with respect to the boom by a second hydraulic actuator. In the event that the supply of hydraulic fluid for powering the actuators fails, the boom may be lowered by gravity by draining fluid from the first hydraulic actuator. To prevent a load from sliding off the load carrier as the boom descends, the load carrier is pivoted to maintain a substantially constant angular relationship to the ground. This is accomplished by selectively conveying fluid drained under pressure from the first hydraulic actuator into the second hydraulic actuator. Changes in the position of the boom are sensed and, in response, the flow of fluid into the second hydraulic actuator is controlled to produce corresponding changes in the load carrier position.

6705079, Mar 16, 2004

Sep 25, 2002

10/255033

Keith A. Tabor - Richfield WI
Joseph L. Pfaff - Wauwatosa WI
Dwight B. Stephenson - Delafield WI

Husco International, Inc. - Waukesha WI

F16D 3102

60469, 91433

When a swinging boom driven by a hydraulic cylinder stops, inertia causes continued motion of the boom which increases pressure in a chamber of the hydraulic cylinder. Eventually that pressure reaches a level which causes the boom to reverse direction. Then pressure in an opposite cylinder chamber increases until reaching a level that causes the boom movement to reverse again. This oscillation continues until the motion is dampened by other forces acting on the boom. As a result, an operator has difficulty in properly positioning the boom. To reduce this oscillating effect, a sensor detects when the cylinder chamber pressure increases above a given magnitude and then a determination is made when the rate of change of that pressure is less than a defined threshold. Upon that occurrence, a control value is opened to relieve the pressure in that cylinder chamber.

6715402, Apr 6, 2004

Feb 26, 2002

10/082862

Joseph L. Pfaff - Wauwatosa WI
Dwight B. Stephenson - Delafield WI

HUSCO International, Inc. - Waukesha WI

F01B 1116

91526, 91530, 91531, 91533

A system for simultaneously operating first and second hydraulic cylinders has an inlet node for connection to a source of pressurized fluid and an outlet node for connection to a tank. A two-position, three-way primary control valve has a first port connected to the inlet node, a second port connected to the outlet node, and a common port. A first electrohydraulic proportional valve connects the common port to a first port of the first cylinder, and a second electrohydraulic proportional valve connects the common port to a first port of the second cylinder. A third electrohydraulic proportional valve connects the inlet node to a second port of the first cylinder and a second port of the second cylinder. Selectively operating the primary control valve and one of the third and fourth electrohydraulic proportional valves determines the direction in which the first and second cylinders move. Operation of the first and second electrohydraulic proportional valves meters hydraulic fluid to or from the first and second cylinders to control the rate of that movement.