Servo-control device for varying the delivery and direction of distribution of a variable delivery pump

Claim 2

A servo-control device for varying the delivery and direction of distribution of a variable delivery pump to a hydraulic motor comprising a member for varying the output of the pump, a two-way distributor valve connected between the outlet of the pump and two inlets of the motor and having two control chambers, an auxiliary two-way distributor valve having two outlets connected respectively to said two control chambers and an inlet connected to the outlet of a feed pump, a control distributor valve having an inlet connected to the feed pump outlet for controlling the supply of fluid to two chambers of a ram, said ram having a piston and a rod connected to said piston and wherein said rod is coupled to the member for varying the output of the variable delivery pump, and a common actuating lever for actuating the spool valves of the auxiliary distributor valve and the control distributor valve.

Claim 3

A device as claimed in claim 1, wherein the spool valve of the auxiliary distributor is pivotally mounted on the actuating lever, an axially movable abutment having said lever pivotally mounted thereon and bearing thereagainst, a linking lever pivotally mounted adjacent one of its extremities on said rod of the ram and pivotally mounted adjacent its other extremity to said abutment, and wherein said spool valve of the control distributor is pivotally connected to said linking lever.

Claim 4

A device as claimed in claim 2, wherein the actuating lever is provided with spaced rollers positioned respectively, on either side of the pivot of said actuating lever, said rollers bearing against an end face of the sliding abutment.

Claim 5

A device as claimed in claim 3, wherein the auxiliary distributor valve includes a return connection normally in communication with its inlet when the distributor spool valve is in a neutral position, said return connection being in communication with a tank through a restrictor in such a manner as to obtain a low pressure fluid fed to the outlet of the feed pump when the auxiliary distribuor spool valve is in the neutral position.

Claim 6

A device as claimed in claim 4, wherein the outlet of the feed pump is connected to a calibrating valve arranged in such manner as to open at an adjustable second pressure which is higher than the pressure normally prevailing in the circuit when the auxiliary distributor spool valve is in the neutral position, this outlet of the feed pump also being connected to a safety brake associated with the hydraulic motor.

Claim 7

A fluid system comprising: a variable displacement pump operable to pressurize a fluid and deliver same at a variable delivery rate as motive fluid and having a movable control member for variably setting tHe delivery rate in dependence upon the position of said control member; a fluid motor actuatable in two different directions in response to motive fluid applied thereto; a main distribution circuit having means receptive of the motive fluid delivered from said variable displacement pump for applying same to said fluid motor and including a fluid-activated directional control valve actuatable into various working positions to control the output direction of said fluid motor in dependence upon the position of said valve; an auxiliary pump operable to pressurize a fluid and deliver same as working fluid; a fluid actuator connected to said control member and responsive to working fluid applied thereto to move said control member to vary the delivery rate of said variable displacement pump; and an auxiliary distribution circuit having means receptive of the working fluid delivered from said auxiliary pump for selectively applying same to both said fluid-actuated directional control valve to actuate same to its various working positions to thereby control the output direction of said fluid motor and to said fluid actuator to actuate same to thereby control the delivery rate of said variable displacement pump.

Claim 8

A fluid system comprising: a variable displacement pump operable to pressurize a fluid and deliver same at a variable delivery rate as motive fluid and having a movable control member for variably setting tHe delivery rate in dependence upon the position of said control member; a fluid motor actuatable in two different directions in response to motive fluid applied thereto; a main distribution circuit having means receptive of the motive fluid delivered from said variable displacement pump for applying same to said fluid motor and including a fluid-activated directional control valve actuatable into various working positions to control the output direction of said fluid motor in dependence upon the position of said valve; an auxiliary pump operable to pressurize a fluid and deliver same as working fluid; a fluid actuator connected to said control member and responsive to working fluid applied thereto to move said control member to vary the delivery rate of said variable displacement pump; and an auxiliary distribution circuit having means receptive of the working fluid delivered from said auxiliary pump for selectively applying same to both said fluid-actuated directional control valve to actuate same to its various working positions to thereby control the output direction of said fluid motor and to said fluid actuator to actuate same to thereby control the delivery rate of said variable displacement pump.

Claim 9

A fluid system according to claim 8; wherein said auxiliary distribution circuit comprises a mechanically-actuated auxiliary directional control valve actuatable into plural working positions to valve the working fluid to and from said fluid-actuated directional control valve to thereby control the actuation of same, a mechanically-actuated control valve actuatable into plural working positions to valve the working fluid to and from said fluid actuator to thereby control the actuation of same, and actuating means including a pivotal actuating lever connected to both said mechanically-actuated auxiliary directional control valve and said mechanically-actuated control valve for effecting concurrent actuation of both said last-named valves in response to pivotal movement of said actuating lever.

Claim 10

A fluid system according to claim 7; wherein said auxiliary distribution circuit includes a feedback linkage assembly interconnecting said mechanically-actuated control valve and said fluid actuator operative to feedback the movement of said fluid actuator to said control valve to reposition same into a neutral position wherein same does not valve working fluid to said fluid actuator to thereby maintain said fluid actuator in a desired position.

Claim 11

A fluid system according to claim 7; wherein said actuating means comprises a slideable member having thereon a pair of abutment surfaces, a pair of camming rollers each rotatably mounted on said actuating lever and engageable with respective ones of said abutment surfaces, means mounting said actuating lever for pivotal movement about an axis situated between said pair of rollers whereby pivotal movement of said actuating lever in either direction effects sliding movement of said slideable member in the same direction due to the camming action of said rollers against said abutment surfaces, and biasing means biasing said actuating lever into a neutral position wherein same does not effect actuation of either said auxiliary directional control valve or said control valve.

Claim 12

A fluid system according to claim 9; wherein said actuating means includes means connecting said auxiliary directional control valve to said actuating lever to effect actuation of the former in response to pivotal movement of the latter, and means connecting said control valve to said slideable member to effect actuation of the former in response to sliding movement of the latter caused by pivotal movement of said actuating lever.

Claim 13

A fluid system according to claim 7; wherein said auxiliary distribution circuit includes brake means for braking said fluid motor whenever the pressure of the working fluid is below a predetermined valve and responsive to the pressure of the working fluid when same reaches said predetermined value to release said brake means.

Claim 14

A fluid system according to claim 7; wherein said auxiliary distribution circuit includes a safety valve operable to bleed the working fluid from said auxiliary distribution circuit independently of the position of said actuating lever, and spring means for biasing said fluid-actuated directional control valve into its neutral position wherein same effects recirculation of the motive fluid delivered from said variable displacement pump whenever the working fluid is bled from said auxiliary distribution circuit.