Hydraulic control and regulating apparatus for an adjustable pump

Claim 2

Hydraulic control and regulating apparatus for an adjustable pump driven by a combustion engine, comprising first adjusting means connected with said adjustable pump and movable in opposite directions for varying the volume of fluid displaced by said adjustable pump at the same speed; an auxiliary pump driven at a speed proportional to the speed of said adjustable pump; high pressure delivery conduit means for said auxiliary pump; throttle means in said delivery conduit means responsive to a predetermined volume of fluid delivered by said auxiliary pump at a predetermined speed to produce a predetermined pressure differential; speed control valve means biassed to a normal inoperative position, and being responsive to said predetermined pressure differential to move to a control position; second adjusting means including shifting valve means having two reversing positions, and connecting said speed control valve means in said control position with said delivery conduit means and with a low pressure discharge space; and hydraulic setting means for said first adjusting means including setting conduit hydraulically connected by said speed control valve means with said delivery conduit means and said discharge space and operating in said control position of said speed control valve means said first adjusting means in opposite directions depending on said reversing positions of said shifting valve means whereby the adjustment of said adjustable pump by direct operation of said first adjusting means is overruled by said second adjusting means so that stalling of said engine is prevented.

Claim 3

Apparatus as claimed in claim 1 wherein said shifting valve means include two shifting valves each movable between an open and a closed position for reversing the flow of fluid through said speed control valve in said control position.

Claim 4

Apparatus as claimed in claim 1 wherein said adjustable pump includes a regulating means; and wherein said first adjusting means include a manually operable linkage connected with said regulating means and also operated by said setting means, an adjustment control valve shiftable by said linkage between an inoperative position and at least one operative position, and hydraulic operating motor means controlled by said adjustment control valve in said operative position to set said regulating means in accordance with the position of said linkage.

Claim 5

Apparatus as claimed in claim 1 wherein said second adjusting means include a manually operated member connected with said shifting valve means.

Claim 6

Apparatus as claimed in claim 1 wherein said adjustable pump has a high pressure outlet conduit; further comprising a throttle and a maximum volume limiting valve connected in parallel in said output conduit, said limiting valve being hydraulically connected with said first adjusting means and operating the same to reduce the volume discharged by said adjustable pump when said limiting valve responds to a predetermined pressure differential produced by said throttle at a maximum volume of fluid pumped through said outlet conduit.

Claim 7

Apparatus as claimed in claim 1 further comprising a check valve connected in parallel with said throttle means in said delivery conduit means of said auxiliary pump, and opening at a pressure higher than said pressure differential produced by said throttle means when the speed of said combustion engine and of said auxiliary pump rises after said speed control valve has moved to said control position.

Claim 8

Apparatus as claimed in claim 1 wherein said first adjusting means include a manual lever operatively connected with said adjustable pump for varying the displaced volume of fluid; wherein said hydraulic setting means include first and second hydraulic setting motors including spring biassed setting pistons abutting said manual lever from opposite sides.

Claim 9

Apparatus as claimed in claim 7 wherein said setting pistons form chambers in said setting motors; and comprising conduits connecting said chambers with ports of said speed control valve means, said speed control valve means having duct means, connecting said conduits with each other in said inoperative position, and with said shifting valve means in said control position.

Claim 10

Hydraulic control and regulating apparatus for an adjustable pump driven by a combustion engine, comprising first Adjusting means connected with said adjustable pump and movable in opposite directions for varying the volume of fluid displaced by said adjustable pump at the same speed; an auxiliary pump driven at a speed proportional to the speed of said adjustable pump; high pressure delivery conduit means for said auxiliary pump; throttle means in said delivery conduit means responsive to a predetermined volume of fluid delivered by said auxiliary pump at a predetermined speed to produce a predetermined pressure differential; speed control valve means biased to a normal inoperative position, and being responsive to said predetermined pressure differential to move to a control position, said speed control valve means having two chambers connected with said delivery conduit upstream and downstream of said throttle means; second adjusting means including shifting valve means having two reversing positions, and connecting said speed control valve means in said control position with said delivery conduit means and with a low pressure discharge space; and hydraulic setting means for said first adjusting means hydraulically connected by said speed control valve means with said delivery conduit means and said discharge space and operating in said control position of said speed control valve means said first adjusting means in opposite directions depending on said reversing positions of said shifting valve means whereby the adjustment of said adjustable pump by direct operation of said first adjusting means is overruled by said second adjusting means so that stalling of said engine is prevented, said hydraulic setting means including first and second chambers, said setting conduits being connected with said chambers and having ports in said speed control valve means, said speed control valve means connecting said ports of said speed control valve means, said ports being connected with said delivery conduit means and with a low pressure discharge space in said control position of said speed control valve means.

Claim 11

Hydraulic control and regulating apparatus for an adjustable pump driven by a combustion engine, comprising first Adjusting means connected with said adjustable pump and movable in opposite directions for varying the volume of fluid displaced by said adjustable pump at the same speed; an auxiliary pump driven at a speed proportional to the speed of said adjustable pump; high pressure delivery conduit means for said auxiliary pump; throttle means in said delivery conduit means responsive to a predetermined volume of fluid delivered by said auxiliary pump at a predetermined speed to produce a predetermined pressure differential; speed control valve means biased to a normal inoperative position, and being responsive to said predetermined pressure differential to move to a control position, said speed control valve means having two chambers connected with said delivery conduit upstream and downstream of said throttle means; second adjusting means including shifting valve means having two reversing positions, and connecting said speed control valve means in said control position with said delivery conduit means and with a low pressure discharge space; and hydraulic setting means for said first adjusting means hydraulically connected by said speed control valve means with said delivery conduit means and said discharge space and operating in said control position of said speed control valve means said first adjusting means in opposite directions depending on said reversing positions of said shifting valve means whereby the adjustment of said adjustable pump by direct operation of said first adjusting means is overruled by said second adjusting means so that stalling of said engine is prevented, said hydraulic setting means including first and second chambers, said setting conduits being connected with said chambers and having ports in said speed control valve means, said speed control valve means connecting said ports of said speed control valve means, said ports being connected with said delivery conduit means and with a low pressure discharge space in said control position of said speed control valve means.

Claim 12

Hydraulic control and regulating apparatus for an adjustable pump driven by a combustion engine, comprising first adjusting means connected with said adjustable pump and movable in opposite directions for varying the volume of fluid displaced by said adjustable pump at the same speed; an auxiliary pump driven at a speed proportional to the speed of said adjustable pump; throttle means in said delivery conduit means responsive to a predetermined volume of fluid delivered by said auxiliary pump at a predetermined speed to produce a predetermined pressure differential; speed control valve means biased to a normal inoperative position, and being responsive to said predetermined pressure differential to move to a control position, said speed control valve means including a cylinder, a valve slide in said cylinder movable between said normal inoperative position and said control position, spring means in said cylinder and biasing said valve slide to said inoperative position, said valve slide having two end chambers in said cylinder connected with said delivery conduit upstream and downstream of said throttle means; second adjusting means including shifting valve means having two reversing positions, and connecting said speed control valve means in said control position with said delivery conduit means and with a low pressure discharge space; and hydraulic setting means for said first adjusting means hydraulically connected to said speed control valve means with said delivery conduit means and said discharge space and operating in said control position of said speed control valve means said first adjusting means in opposite directions depending on said reversing positions of said shifting valve means whereby the adjustment of said adjustable pump by direct operation of said first adjusting means is overruled by said second adjusting means so that stalling of said engine is prevented, said hydraulic setting means including first and second cylinders, first and second setting pistons formiNg chambers in said cylinders, springs in said chambers biasing said setting pistons from opposite sides against said first adjusting means; said setting conduits including two setting conduits connected with said chambers, respectively, and having ports in said speed control valve means, said speed control valve means connecting said ports of said two setting conduits in said inoperative position of said speed control valve means, said ports being connected in said control position of said speed control valve means with said delivery conduit means and with a low pressure discharge space.

Claim 13

Hydraulic control and regulating apparatus for an adjustable pump driven by a combustion engine, comprising first adjusting means connected with said adjustable pump and movable in opposite directions for varying the volume of fluid displaced by said adjustable pump at the same speed; an auxiliary pump driven at a speed proportional to the speed of said adjustable pump; throttle means in said delivery conduit means responsive to a predetermined volume of fluid delivered by said auxiliary pump at a predetermined speed to produce a predetermined pressure differential; speed control valve means biased to a normal inoperative position, and being responsive to said predetermined pressure differential to move to a control position, said speed control valve means including a cylinder, a valve slide in said cylinder movable between said normal inoperative position and said control position, spring means in said cylinder and biasing said valve slide to said inoperative position, said valve slide having two end chambers in said cylinder connected with said delivery conduit upstream and downstream of said throttle means; second adjusting means including shifting valve means having two reversing positions, and connecting said speed control valve means in said control position with said delivery conduit means and with a low pressure discharge space; and hydraulic setting means for said first adjusting means hydraulically connected to said speed control valve means with said delivery conduit means and said discharge space and operating in said control position of said speed control valve means said first adjusting means in opposite directions depending on said reversing positions of said shifting valve means whereby the adjustment of said adjustable pump by direct operation of said first adjusting means is overruled by said second adjusting means so that stalling of said engine is prevented, said hydraulic setting means including first and second cylinders, first and second setting pistons formiNg chambers in said cylinders, springs in said chambers biasing said setting pistons from opposite sides against said first adjusting means; said setting conduits including two setting conduits connected with said chambers, respectively, and having ports in said speed control valve means, said speed control valve means connecting said ports of said two setting conduits in said inoperative position of said speed control valve means, said ports being connected in said control position of said speed control valve means with said delivery conduit means and with a low pressure discharge space.

Claim 14

Apparatus as claimed in claim 10 wherein said adjustable pump includes a regulating means; and wherein said first adjusting means include a linkage connected with said regulating means and operated by said setting means, an adjustment control valve shiftable by said linkage between an inoperative position and at least one operative position, and hydraulic operating motor means controlled by said adjustment control valve in said operative position to set said regulating means in accordance with the position of said linkage; wherein said second adjusting means includes a manually operated lever connected with said shifting valve means; wherein said first adjusting means include a manual lever forming a part of said linkage; and wherein said setting pistons abut said manual lever of said first adjusting means.