Power steering gear

Claim 2

A fluid power steering apparatus comprising a stepped cylinder having a first enclosed bore and a second enclosed bore of enlarged size, an offset piston slidable within said cylinder including a body fitting said first bore and an enlarged section fitting within said second bore, a driving rack on said body, a driven pinion in engagement with said rack, a source of pressurized fluid, means for directing said fluid to and from first and second driving chambers only one at a time on opposite sides of said piston whereby said opposite sides are fully effective for driving said piston, and a return chamber for said fluid serving to enclose said driving chambers to maintain the same separate whereby said return chamber is subjected only to return pressure, said directing means includes a valve and connecting passage means for simultaneously directing said fluid to said third chamber on one side of said enlarged section and to said first chamber on the corresponding operating end of said body, said second chamber being positioned on the opposite side of said enlarged section.

Claim 3

The apparatus of claim 1 wherein said passage means extends substantially along the length of said piston and includes a recess formed in said one side of said section and a channel extending the full length of said body and communicating with said recess, whereby to allow full travel of said piston.

Claim 4

A fluid power steering apparatus comprising a stepped cylinder having a first enclosed bore and a second enclosed bore of enlarged size, an offset piston slidable within said cylinder including a body fitting said first bore and an enlarged section fitting within said second bore, a driving rack on said piston, said body and said first bore forming sealing areas at the ends of said rack, a driven pinion in engagement with said rack, a source of pressurized fluid, means for directing said fluid to and from first and second driving chambers only one at a time on opposite sides of said piston whereby said opposite sides are fully effective for driving saId piston, said driven pinion having a first set of gear teeth engaging said rack, and a reserve set of gear teeth spaced from and independent of said first set, and means for repositioning said pinion to bring said reserved set into engagement with said rack, said first set and said reserved set being spaced from each other by a reduced land extending inside the depth of the teeth to prevent interference with the sealing area of said body at the ends of said rack, a third driving chamber around said body for cooperation in driving with said first driving chamber, and said directing means includes a valve and connecting passage means for simultaneously directing said fluid to said third chamber on one side of said enlarged section and to said first chamber on the corresponding operating end of said body, said second chamber being positioned on the opposite side of said enlarged section.

Claim 5

A fluid power steering apparatus comprising a stepped cylinder having a first enclosed bore and a second enclosed bore of enlarged size, an offset piston slidable within said cylinder including a body fitting said first bore and an enlarged section fitting within said second bore, a driving rack on said piston, said body and said first bore forming sealing areas at the ends of said rack, a driven pinion in engagement with said rack, a source of pressurized fluid, means for directing said fluid to and from first and second driving chambers only one at a time on opposite sides of said piston whereby said opposite sides are fully effective for driving saId piston, said driven pinion having a first set of gear teeth engaging said rack, and a reserve set of gear teeth spaced from and independent of said first set, and means for repositioning said pinion to bring said reserved set into engagement with said rack, said first set and said reserved set being spaced from each other by a reduced land extending inside the depth of the teeth to prevent interference with the sealing area of said body at the ends of said rack, a third driving chamber around said body for cooperation in driving with said first driving chamber, and said directing means includes a valve and connecting passage means for simultaneously directing said fluid to said third chamber on one side of said enlarged section and to said first chamber on the corresponding operating end of said body, said second chamber being positioned on the opposite side of said enlarged section.

Claim 6

The combination of claim 3 wherein said first set of teeth, said reserved set of teeth and said separating lands between said teeth each occupy substantially one quadrant of said pinion.

Claim 7

In a power steering device for vehicles, the combination with a stepped cylinder, an offset piston slidable therein, said piston being formed of a body and an enlarged section, means for detachably securing said body and said enlarged section together, said enlarged section being of larger diameter than said body, a first driving chamber on one end of said body, a second driving chamber on one side of said enlarged section and a third driving chamber acting on the opposite side of said enlarged section and positioned around said body at the interconnection between said body and said enlarged section for acting in concert with said first driving chamber.

Claim 8

In a power steering device for vehicles, the combination with a stepped cylinder, an offset piston slidable therein, said piston being formed of a body and an enlarged section, means for detachably securing said body and said enlarged section together, said enlarged section being of larger diameter than said body, a first driving chamber on one end of said body, a second driving chamber on one side of said enlarged section and a third driving chamber acting on the opposite side of said enlarged section and positioned around said body at the interconnection between said body and said enlarged section for acting in concert with said first driving chamber.

Claim 9

The combination of claim 5 wherein said body consists of an elongated body and said enlarged section consists of a disc mounted on one side of said body.

Claim 10

In a power steering device for vehicles, the combination with a cylinder and a piston slidable therein of a limit control valve in at least one end of said piston, an extensible probe mounted on said cylinder adjacent the limit of travel of said piston, said probe being adapted to operate said control valve, an O-ring extending around said probe, said O-ring having sufficient cross-sectional thickness between said probe and said cylinder without axial compression to prevent loss of fluid under pressure of said driving chamber and to frictionally retain said probe against rotation and thus maintain the same in a fixed adjusted position.

Claim 11

In a power steering device for vehicles, the combination with a cylinder and a piston slidable therein of a limit control valve in at least one end of said piston, an extensible probe mounted on said cylinder adjacent the limit of travel of said piston, said probe being adapted to operate said control valve, an O-ring extending around said probe, said O-ring having sufficient cross-sectional thickness between said probe and said cylinder without axial compression to prevent loss of fluid under pressure of said driving chamber and to frictionally retain said probe against rotation and thus maintain the same in a fixed adjusted position.

Claim 12

In a power steering device of claim 7 wherein said probe threadedly engages said cylinder, said O-ring being positioned away from said driving chamber by said threads.