Combined draft hook operating and draft sensing

Claim 2

A tractor hitch comprising: a vertically swingable draft member means including latching surface means projecting therefrom; draft hook means vertically pivotally connected to said draft member means in the vicinity of said latching surface means and including generally upwardly opening receptacle means, said hook means being swingable between an implement part receiving position wherein said receptacle means is spaced away from said surface means and an implement part retaining position wherein said receptacle means is beneath said surface means; and power means including motor means connected between said draft member means and said hook means for swinging the hook means between said receiving and retaining positions; and said motor means including draft load sensing means for sensing and generating a signal representative of draft forces imposed on said draft hook means by an implement attached thereto; second motor means being connected to said draft member means for raising and lowering the latter; motor control means connected to said second motor means and being responsive to draft signals representative of draft loads above and below a preselected draft load for respectively actuating said second motor means from a neutral condition holding said draft member means in place to first and second active conditions for respectively raising and lowering said draft member means for adjusting the vertical height of an implement connected to said draft hook means for causing an attendant decrease and increase in the draft loads imposed on said draft hook means to restore said preselected draft load thereon; and signal transferring means interconnecting said draft load sensing means and said motor control means.

Claim 3

The invention defined in claim 1 wherein said receptacle means is generally semi-circular as viewed in the direction of the pivot axis of said hook means and said surface means forming a continuation of said receptacle means when the hook means is in said retaining position.

Claim 4

The invention defined in claim 1 wherein said draft member means includes a pair of draft links and wherein said motor means includes a pair of motors respectively carried by said pair of draft links; said draft load sensing means including a pair of draft load sensing means respectively embodied in said pair of motor means; and said signal transferring means including means for transferring only the largest of the signals generated at any one time respectively by the pair of draft load sensing means.

Claim 5

The invention defined in claim 1 wherein said draft member means includes a pair of draft links and wherein said motor means includes a pair of motors respectively carried by said pair of draft links; said draft load sensing means including a pair of draft load sensing means respectively embodied in said pair of motor means; and said signal transferring means including means for transferring the sum of the signals generated at any one time respectively by the pair of draft load sensing means.

Claim 6

The invention defined in claim 1 wherein said motor means comprises extensible and retractable hydraulic actuator means including cylinder means having head end means pivotally connected to said draft member means and containing integral piston means and rod means, the rod means projecting from said cylinder means and being pivotally connected to said hook means; biasing means urging said hook means toward said receiving position; said power means further including pressure fluid source means and sump means connected to control valve means, feed line means and return line means connecting control valve means to said cylinder means and said control valve means being selectively operable for connecting said source means to said cylinder means for shifting said rod and piston means in a direction opposing said biasing means for moving said hook means to said retaining position, and for connecting said sump means to said cylinder means for exhausting the latter and permitting said biasing means to move said hook means to said receiving position; a second hydraulic actuator means connected to said draft member means for raising and lowering the latter; pressure responsive control valve means connected to said source means, said sump means and said second actuator means and being responsive to pressures above and below a preselected pressure for respectively acTuating said second actuator means from a neutral condition holding said draft member means in place to first and second active conditions for respectively raising and lowering said draft member means for adjusting the vertical height of an implement connected to said draft hook means for causing an attendant decrease and increase in the draft loads imposed on said draft hook means; and said cylinder means being connected to said pressure responsive control valve means; and said predetermined pressure being at least as large as that required to move said draft hook means against said biasing means to said retaining position.

Claim 7

The invention defined in claim 5 wherein said biasing means comprises coil spring means compressed between the head end means of said cylinder means and said piston means.

Claim 8

The invention defined in claim 5 wherein said return line means includes a return branch line means, exclusive of said control valve means, connecting said cylinder to said sump; said return branch line means containing flow restrictor means for maintaining the pressure in said cylinder at a value sufficient for maintaining said rod and piston means in a position holding said hook means in said retaining position.

Claim 9

The invention defined in claim 7 wherein said return branch line means contains a pilot-operated check valve means normally being in a closed position blocking flow to the sump and being connected to said source means and responsive to the pressure of the fluid delivered by the source means for shifting to an open position connecting the return branch line means to the sump; and one-way check valve means being located in said feed line means for preventing the reversal of flow therein in a direction from the cylinder means toward the control valve means, whereby fluid pressure in the cylinder means will be maintained in the event of feed line failure or in the event that the source means ceases to operate.

Claim 10

The invention defined in claim 7 wherein said hydraulic actuator means further includes position responsive valve means for increasingly restricting the flow of pressure fluid to the cylinder means, as the piston and rod means moves from a first position, for holding the draft hook means in its receiving position, to a second position for holding the draft hook means in its retaining position.

Claim 11

The invention defined in claim 7 wherein said piston means bridges the location of the connection of said valve means with said cylinder means; valve bore means extending axially in said piston means and having open end means oriented in the direction of action of said biasing means, passage means in said piston means including port means fluid-connecting the bore means with the connection of said valve means with said bore means; and position responsive valve means shiftably mounted in said bore means for controlling the flow of fluid from said port means to said open end means by increasingly restricting said port means in response to the piston means moving from a first position, wherein the hook means is in its receiving position, to a second position, wherein the hook means is in its retaining position.

Claim 12

For a tractor having a vertically swingable draft linkage, power lift means for selectively adjusting the vertical disposition of said linkage and a control means for controlling actuation of said power lift means in response to signals representative of draft forces exerted on said linkage so as to raise and lower said linkage respectively when the draft forces are greater and lesser than a preselected draft force, a novel hitch apparatus comprising: a hook means pivotally mounted on said draft linkage for swinging between an implement part receiving position and an implement part retaining position wherein draft loads imposed by the implement on said hook means tend to pivot the latter to the receiving position; a combined actuating and draft force sensing means carried by said linkage and connected to said hook means for moving the latter bEtween said part receiving and retaining positions and for sensing draft forces imposed on said hook means and generating signals representative of the draft forces; and signal transferring means connected between said actuating and draft sensing means and said control means for causing the latter to actuate said power lift means in response to signals representative of draft forces above and below a preselected force, to adjust the vertical disposition of the linkage to restore said preselected draft force thereon.

Claim 13

For a tractor having a vertically swingable draft linkage, power lift means for selectively adjusting the vertical disposition of said linkage and a control means for controlling actuation of said power lift means in response to signals representative of draft forces exerted on said linkage so as to raise and lower said linkage respectively when the draft forces are greater and lesser than a preselected draft force, a novel hitch apparatus comprising: a hook means pivotally mounted on said draft linkage for swinging between an implement part receiving position and an implement part retaining position wherein draft loads imposed by the implement on said hook means tend to pivot the latter to the receiving position; a combined actuating and draft force sensing means carried by said linkage and connected to said hook means for moving the latter bEtween said part receiving and retaining positions and for sensing draft forces imposed on said hook means and generating signals representative of the draft forces; and signal transferring means connected between said actuating and draft sensing means and said control means for causing the latter to actuate said power lift means in response to signals representative of draft forces above and below a preselected force, to adjust the vertical disposition of the linkage to restore said preselected draft force thereon.

Claim 14

The invention defined in claim 11 wherein said actuating and draft sensing means comprises cylinder means having head end means pivotally connected to said draft linkage means and containing integral piston means and rod means, the rod means projecting from said cylinder means and being pivotally connected to said hook means; biasing means urging said hook means toward said receiving position; said power lift means including a hydraulic motor; a source of fluid pressure and a reservoir; said control means being a pressure responsive valve connected between said hydraulic motor and said source and reservoir and responsive to pressure above and below a preselected pressure for respectively actuating said motor from a neutral condition holding said draft linkage means fixed to first and second conditions for respectively raising and lowering said linkage means for adjusting the vertical height of an implement connected to the hook means for causing an attendant decrease and increase in the draft loads imposed on said hook means; and said cylinder means being connected to said pressure responsive valve means; and said predetermined pressure being at least as large as that required to move said draft hook means against said biasing means to said retaining position.

Claim 15

A tractor hitch comprising: a vertically swingable draft member means, draft receptacle means including at least one part means movably connected to said draft member means for movement generally in the direction of draft between a rearward position wherein an implement part can be received in said receptacle means and a forward position wherein an implement part received in said receptacle will be retained in the latter and will be in bearing engagement with said one part means; power means including motor means connected between said member means and said one part means for moving the one part means between said rearward and forward positions; said motor means including draft load sensing means for sensing and generating a signal representative of draft forces imposed on said one part means by an implement having a part retained in said receptacle means; second motor means being connected to said draft member means for raising and lowering the latter; motor control means connected to said second motor means and being responsive to draft signals representative of draft loads above and below a preselected draft load for respectively actuating said second motor means from a neutral condition, holding said draft member means in place, to first and second active conditions for respectively raising and lowering said draft member means for adjusting the vertical height of an implement connected to said draft hook means for causing an attendant decrease and increase in the draft loads imposed on said one part means to restore said preselected draft load thereon; and signal transferring means interconnecting said load sensing means and said motor control means.

Claim 16

A tractor hitch comprising: a vertically swingable draft member means, draft receptacle means including at least one part means movably connected to said draft member means for movement generally in the direction of draft between a rearward position wherein an implement part can be received in said receptacle means and a forward position wherein an implement part received in said receptacle will be retained in the latter and will be in bearing engagement with said one part means; power means including motor means connected between said member means and said one part means for moving the one part means between said rearward and forward positions; said motor means including draft load sensing means for sensing and generating a signal representative of draft forces imposed on said one part means by an implement having a part retained in said receptacle means; second motor means being connected to said draft member means for raising and lowering the latter; motor control means connected to said second motor means and being responsive to draft signals representative of draft loads above and below a preselected draft load for respectively actuating said second motor means from a neutral condition, holding said draft member means in place, to first and second active conditions for respectively raising and lowering said draft member means for adjusting the vertical height of an implement connected to said draft hook means for causing an attendant decrease and increase in the draft loads imposed on said one part means to restore said preselected draft load thereon; and signal transferring means interconnecting said load sensing means and said motor control means.

Claim 17

The invention defined in claim 13 wherein said motor means comprises extensible and retractable hydraulic actuator means.

Claim 18

The invention defined in claim 14 wherein said hydraulic actuator means includes cylinder means having head end means pivotally connected to said draft member means and containing integral piston means and rod means; the rod means projecting from said cylinder means and being pivotally connected to said one part means of said receptacle means; biasing means urging said one part means toward said rearwarD position; and power means further including pressure fluid source means and sump means connected to control valve means, said valve means being in turn connected to said cylinder means and being selectively operable for connecting said source means to said cylinder means for shifting said rod and piston means in a direction opposing said biasing means for moving said one part means to said forward position, and for connecting said sump means to said cylinder means for exhausting the latter and permitting said biasing means to move said one part means to said rearward position.

Claim 19

The invention defined in claim 15 and further including a second hydraulic actuator means connected to said draft member means for raising and lowering the latter; pressure responsive control valve means connected to said source means, said sump means and said second actuator means and being responsive to pressure above and below a preselected pressure for respectively actuating said second actuator means from a neutral condition holding said draft member means in place to first and second active conditions for respectively raising and lowering said draft member means for adjusting the vertical height of an implement having a part retained in said receptacle means for causing an attendant decrease and increase in the draft loads imposed on said one part means; and said cylinder means being connected to said pressure responsive control valve means; and said predetermined pressure being at least as large as that required to move said one part means against said biasing means to said forward position.

Claim 20

The invention defined in claim 15 wherein said hydraulic actuator means further includes position responsive valve means for increasingly restricting the passage of fluid to the rod end means of said cylinder means in response to said piston means moving from a first position, wherein the one part means is in its rearward position, to a second position wherein the one part means is in its forward position.

Claim 21

The invention defined in claim 15 wherein said piston means bridges the location of the connection of said valve means with said cylinder means; valve bore means extending axially in said piston means and having open end means oriented in the direction of action of said biasing means, passage means in said piston means including port means fluid-connecting the bore means with the connection of said valve means with said bore means; and position responsive valve means shiftably mounted in said bore means for controlling the flow of fluid from said port means to said open end means by blocking said port means in response to the piston means reaching a preselected axial position in said cylinder means.

Claim 22

The invention defined in claim 18 wherein said position responsive valve means comprises valve spool means having land means slidably received in said bore means and stem means projecting through said open end means of said bore means and means biasing said spool means towards a position wherein said stem means is engaged with an end means of said cylinder means.