Multiple speed hydraulic gear motor driven gear unit

Claim 2

In a hydraulic power transmission system having a rotary output shaft subject to external loads tending to rotate the shaft in at least one direction: at least first and second rotary, fixed displacement fluid drive motors of unequal displacement coupled to the shaft for common rotation therewith, said first and second motors each being responsive to delivery of motive inlet fluid flow to respective one sides thereof to rotate said shaft in said one direction and to effect consequent displacement of exhaust fluid from both of said first and second motors at respective sides thereof opposite said one sides; means operatively coupled with said one sides of both said first and second motors for selectively directing said motive inlet fluid flow to said one side of the first motor and to said one side of the second motor in different operational modes; and flow control means disposed in the path of exhaust flow from said opposite side of the first motor and operatively coupled with said one sides of both the first and second motors to be responsive to pressure of said motive inlet fluid flow in both of said different operational modes, said flow control means being in a position for blocking exhaust flow from said one side of the first motor to prevent shaft rotation in said one direction in both of said different operational modes whenever said motive inlet pressure is below a predetermined level, and said flow control means being shiftable to a position for permitting exhaust flow from said one side of the first motor to allow shaft rotation in said one direction in response to a rise in said motive inlet pressure above said predetermined level.

Claim 3

A system as set forth in claim 1, wherein said flow control means includes: a pressure responsive control member disposed in the path of exhaust flow from said one side of the first motor to control exhaust flow therefrom; and pressure conducting means for interconnecting said control member with both said one sides of the first and second motors so that said control member is responsive to said motive inlet pressure to shift between said flow-blocking and flow-permitting positions in both of said different operational modes.

Claim 4

A system as set forth in claim 2, wherein is provided first and second flow restrictors interposed in said pressure-conducting means at positions between said control member and said one sides of the first and second motors respectively, said restrictors being operable to restrict fluid communication between said one sides of the first and second motors through said pressure-conducting means.

Claim 5

A system as set forth in claim 3, wherein said pressure-conducting means includes: a feed conduit communicating with said control member; and first and second pilot conduits respectively interconnecting said one sides of the first and second motors with said feed conduit, said first and second flow restrictors being respectively interposed in said first and second pilot conduits.

Claim 6

A system as set forth in claim 2, wherein is provided biasing means operatively engaging said control member for urging the latter to its flow-blocking position in opposition to the urgings of said motive inlet pressure, said biasing means being operable to normally hold said control member in said flow-blocking position whenever said motive inlet pressure is below said predetermined level.

Claim 7

A system as set forth in claim 2, wherein said control member is variably positionable in response to the magnitude of said motive inlet pressure to effect correspondingly variable restriction of exhaust flow from said one side of the first motor in both of said different operational modes.

Claim 8

A system as set forth in claim 1, wherein said flow-directing means are selectively operable in a combined operational mode to direct said motive inlet fluid flow simultaneously to said one sides of both the first and second motors, said flow control means being operable in said different and said combined operational modes to prevent shaft rotation in said one direction whenever said motive inlet pressure is below said predetermined level.

Claim 9

A system as set forth in claim 1, wherein said flow-directing means are operatively coupled with said one and said opposite sides of both the first and second motors, said flow-directing means being operable in a first operational mode to direct said motive inlet flow to said one side of the first motor while operatively interconnecting said one side and said opposite side of the second motor, and being operable in a second operational mode to direct said motive inlet flow to said one side of the second motor while operatively interconnecting said one side and said opposite side of the first motor downstream of said flow control means.

Claim 10

A system as set forth in claim 1, wherein said flow-directing means are operatively coupled with said one and said opposite sides of both the first and second motors, said flow-directing means being selectively operable to direct said motive inlet fluid flow to said opposite side of said first motor and to said opposite side of the second motor in different reverse modes to effect rotation of said motors in the shaft in a direction opposite said one direction at different speeds in said different reverse modes.

Claim 11

A system as set forth in claim 9 wherein is provided: a bypass conduit communicating with said opposite side of the first motor in parallel relationship with said flow control means for carrying fluid flow into said opposite side of the first motor upon rotation of the shaft in said opposite direction; and an unidirectional check valve interposed in said bypass conduit for preventing passage of exhaust flow from said opposite side of the first motor through said bypass conduit upon rotation of the shaft in said one direction.

Claim 12

A system as set forth in claim 1 wherein said first and second motors respectively include first and second sets of intermeshing gears, said gear sets being of unequal width; and wherein is provided a unitary motor housing for enclosing and hydraulically separating said first and second gear sets, said shaft being rotatably mounted within said motor housing and being operatively secured to said first and second gear sets.

Claim 13

A system as set forth in claim 11 wherein is provided a power winch coupled to said shaft for rotation therewith, said winch including a winding spool secured upon said shaft at a working station proximal to said unitary motor housing.

Claim 14

A system as set forth in claim 12 wherein said first gear set of said first motor is wider than said second gear set and is operatively secured upon said shaft at a location nearer said working station than is said second gear set.

Claim 15

A hydraulic system as set forth in claim 12 wherein is provided: mechanical brake means for normally operatively engaging said shaft to prevent rotation thereof in said one direction when said brake means is applied; and brakeoperating means operatively coupled with said brake means and said flow control means for releasing said brake means to permit rotation of said shaft in said one direction in response to said motive inlet pressure whenever the latter exceeds a preselected level which is substantially lower than said predetermined level at which said flow control means shifts to said flow-permitting position.

Claim 16

A system as set forth in claim 14 wherein is provided an overrunning clutch interposed between and operatively coupled with said shaft and said brake means for permitting free rotation of said shaft in a direction opposite said one direction even while said brake means is applied.

Claim 17

In a multiple speed drive for planetary winches: a rotary power drive shaft; a winch winding spool secured to the shaft at a working station and adapted to effect movement of a load in opposite directions upon opposite rotation of the shaft; a stationary hydraulic drive motor housing positioned at a location proximal to said working station, said shaft being journalled within said motor housing; first and second rotary hydraulic gear motor sections of unequal width carried in said housing, each section being operatively secured to the shaft for common rotation therewith in said one direction; supply means operatively coupled with said motor housing for delivering motive inlet fluid flow thereto; means interposed between said supply means and said first and second motor sections for selectively directing motive inlet fluid flow in a first operational mode to one side oF said first motor section to effect shaft rotation in said one direction at one speed, and for directing said motive inlet fluid flow in a second operational mode to one side of said second motor section to effect shaft rotation in said one direction at a different speed, each of said motors being operable in both of said first and second operational modes to displace fluid from respective sides thereof opposite said one sides; and pressure operated control means operatively coupled with said one sides of both of the first and second motors and disposed in the path of exhaust flow from said opposite side of the first motor, said control means being operable for blocking exhaust flow from said opposite side of the first motor to prevent shaft rotation in said one direction in both of said first and second operational modes whenever pressure of said motive inlet pressure fluid is below a predetermined level.

Claim 18

In a multiple speed drive for planetary winches: a rotary power drive shaft; a winch winding spool secured to the shaft at a working station and adapted to effect movement of a load in opposite directions upon opposite rotation of the shaft; a stationary hydraulic drive motor housing positioned at a location proximal to said working station, said shaft being journalled within said motor housing; first and second rotary hydraulic gear motor sections of unequal width carried in said housing, each section being operatively secured to the shaft for common rotation therewith in said one direction; supply means operatively coupled with said motor housing for delivering motive inlet fluid flow thereto; means interposed between said supply means and said first and second motor sections for selectively directing motive inlet fluid flow in a first operational mode to one side oF said first motor section to effect shaft rotation in said one direction at one speed, and for directing said motive inlet fluid flow in a second operational mode to one side of said second motor section to effect shaft rotation in said one direction at a different speed, each of said motors being operable in both of said first and second operational modes to displace fluid from respective sides thereof opposite said one sides; and pressure operated control means operatively coupled with said one sides of both of the first and second motors and disposed in the path of exhaust flow from said opposite side of the first motor, said control means being operable for blocking exhaust flow from said opposite side of the first motor to prevent shaft rotation in said one direction in both of said first and second operational modes whenever pressure of said motive inlet pressure fluid is below a predetermined level.