US3613798A - Hydraulic control system for agricultural implements - Google Patents

Hydraulic control system for agricultural implements Download PDF

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Publication number
US3613798A
US3613798A US822252A US3613798DA US3613798A US 3613798 A US3613798 A US 3613798A US 822252 A US822252 A US 822252A US 3613798D A US3613798D A US 3613798DA US 3613798 A US3613798 A US 3613798A
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United States
Prior art keywords
valve
draft
cam
control mechanism
lever
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Expired - Lifetime
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US822252A
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English (en)
Inventor
Chandra Mohan
Gursharan Singh Rihal
Balbir Singh Devgun
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Council of Scientific and Industrial Research CSIR
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Council of Scientific and Industrial Research CSIR
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Classifications

    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
    • A01B63/00—Lifting or adjusting devices or arrangements for agricultural machines or implements
    • A01B63/02—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors
    • A01B63/10—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors operated by hydraulic or pneumatic means
    • A01B63/111—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors operated by hydraulic or pneumatic means regulating working depth of implements
    • A01B63/1117—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors operated by hydraulic or pneumatic means regulating working depth of implements using a hitch position sensor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/87917—Flow path with serial valves and/or closures
    • Y10T137/88022—One valve head provides seat for other head

Definitions

  • a control mechanism for agricultural implements mounted on three-point linkages in tractors includes a valve mechanism which controls the hydraulic circuit.
  • a single selection and operational control device operates the implements and draftand position-sensing means act through a cam and lever arrangement for controlling the operation of the valve mechanism which includes two concentrically arranged valve members for regulating the flow of the fluid in the hydraulic circuit.
  • HYDRAULIC CONTROL SYSTEM FOR AGRICULTURAL IMPLEMENTS This invention relates to the hydraulic system and allied controls provided on tractors for working implements of the mounted type, such tractors being provided with the wellknown three-point linkage and single-acting hydraulic ram for lifting, holding and lowering the implements.
  • the purpose of this invention is to effectively and conveniently control the working depth of the implement by a single operating lever, a new type of control valve and associated linkage, necessary feedback system and a pump combination with the same.
  • each position of the operating lever in its draft control range corresponds to a particular soil draft of the implement and the draft is maintained at the value set on the operating lever irrespective of varying conditions of soil, the implement moving up or down in the soil automatically for maintaining the soil draft at the set value.
  • Known hydraulic systems are either adapted for control of the suction side (low-pressure side) of a pump or the discharge side (high-pressure side) of a pump.
  • This invention relates particularly to a control mechanism adapted for operation on the suction side of a pump.
  • Known suction systems usually incorporate a single control valve actuated by the operational means through a hinged floating lever, the responsive means being connected to the hinge of the said floating lever.
  • the control valve is actuated by the operational means in one direction to either cause the entry or the discharge of high-pressure fluid to the hydraulic cylinder, the responsive means connected to the hinge point serving to actuate the value in the reverse directions; the said control valve reaching its neutral position when both entry into and discharge from the hydraulic,
  • a mechanism for the regulation of hydraulic circuits in tractors for controlling the movement and working of mounted implements attached to the three-point linkage comprising a valve mechanism controlling the working of the said hydraulic circuit, a single selection and operational control means for providing selective working of the said implement and controlling its working and, a responsive means provided and adapted to receive an actuation movement from the implement through actuation draftand positionsensing means, said responsive means also adapted to receive an actuation from said selection means, said valve mechanism comprising at least a first and second control valve disposed therein, said second valve disposed within said first valve, the said first valve being actuated by the said selection and operational means and the said second valve being capable of actuation by the responsive means.
  • This invention which is a control mechanism for a tractor having a hydraulic actuator for raising and lowering implements includes a control valve" constituted of two concentric valves termed hereafter as the spool valve and the annular sleeve valve, means for actuating one of these valves from the operating lever and the other from the feedback signals which could be received either from the draft or position sensors, means whereby the valve movement is connected to either the position or the draft sensors automatically depending upon whether the operating lever is in its position control" or draft control range,” means for protection of the system against overloads and faulty operation and, means for varying system response.
  • a control valve constituted of two concentric valves termed hereafter as the spool valve and the annular sleeve valve, means for actuating one of these valves from the operating lever and the other from the feedback signals which could be received either from the draft or position sensors, means whereby the valve movement is connected to either the position or the draft sensors automatically depending upon whether the operating lever is in its position control" or draft control range," means for protection of
  • the invention makes a fundamental departure from known systems in the control valve," where the operating lever and the feedbacks independently operate the annular sleeve and the spool valves and the operational conditions of the control valve is dependent upon the instantaneous relative position of the spool and the annular sleeve valves.
  • Another feature of the invention is the automatic switchover of the operating means for one of the valves from the position to the draft feedback sensors as the main operating lever is moved over from its position control range to the draft control range and vice versa and, the arrangements provided therein for system protection.
  • Another new introduction is in that the selection of position or draft working and the working depth of the implement both in position and draft control and also the working of single-acting external rams are all effected with a single operating lever, which goes towards more convenient operator handling of the tractor.
  • FIG. 1 is a schematic view of the rear end of a tractor fitted with the invention in conjunction with the three-point linkage;
  • FIG. 2 is a sectional view of the main control valve
  • FIG. 3 shows the operating lever and its sector with the vari ous operating ranges
  • FIG. 4 shows the working of the system in automatic draft control
  • FIG. 5 shows the working of the system in position control
  • FIG. 6 shows the arrangement of the central cam
  • FIG. 7 shows the overload relief arrangement
  • FIG. 8 shows another embodiment of the overload relief engagement.
  • single-acting piston 2 works in hydraulic cylinder 1 and actuates lift shaft 3, to the ends of which are attached radial lift arms 4 directed rearwardly.
  • Radial lift arms 4 are connected to the forwardly converging lower links 6 of the three-point linkage through lift rods 5, one of which is ad justable.
  • Upper link 7 of the three-point linkage is provided with the draft sensor spring assembly 9 which provides the feedback for draft.
  • the three-point linkage carries implement 8.
  • the draft sensor spring assembly 9 is bolted to the rear end of the tractor, the connections to the spring being so arranged that it responds to both compressive and tensile forces in the upper link.
  • a helical spring is typically used as the sensor spring, but any other type of spring, viz flat, volute, torsion bar etc. could be adapted for use.
  • the position feedback.” signal is obtained from cam 10 on lift shaft 3.
  • Control valve 13 is provided on the suction side of pump 11 and remains immersed in sump 12. Suction control of pump 11 avoids unnecessary power loss in the pump and the consequent overheating of oil when the system is in the neutral/hold position. An adaptation of the control valve could, however, also be used for provision on the high-pressure side of the pump.
  • Conduit 14 connects control valve 13 to the sump suction. High-pressure oil from pump 11 is delivered to hydraulic cylinder 1 through conduit 15 for lifting of the lower links 6. Conduit 16 connects hydraulic cylinder 1 to control valve 13 for exhausting the oil in the hydraulic cylinder, the oil flowing through response control" valve 17, so that the speed of lowering of the implements 8 is controlled in accordance with the setting of the response control valve.
  • Control valve 13 consists of valve body 18 in which slides annular sleeve valve 19. Spool valve 20 in turn slides in this annular sleeve valve 19. Operational condition of the control valve at any instant depends upon the relative position of the spool and annular sleeve valves and 19. Passages 21 and 22 in valve body 18 are connected to the pump suction through conduit 14, and to the hydraulic cylinder 1 through conduit 16 respectively. Communication between drilled ports 23 and 24 on the annular sleeve valve 19 and passages 21 and 22 respectively in the sliding range of the annular sleeve valve 19 is ensured by providing annular grooves 19A on the outer periphery of the annular sleeve valve 19 of the sufficient width.
  • Both the spool valve 20 and the annular valve 19 are urged in the rearward direction S1 by springs 29 and 28 respectively to maintain positive contact with their respective actuating levers. Both ends of the spool valve 20 are open to sump l2 and since the control valve 13 is operated when immersed in sump 12, it always remains filled with oil.
  • Annular sleeve valve 19 is extended forward into fork 25 which engages with oscillating sleeve 26 through pin 27.
  • a eccentric drive not shown, oscillates the annular sleeve valve 29 through oscillating sleeve 26.
  • the length of the fork 25 is such that pin 27 on oscillating sleeve 26 remains in engagement with the annular sleeve valve 19 in its entire sliding range. This oscillatory motion reduces the friction between the annular sleeve valve 19 and the spool valve 20 on one hand and the an nular sleeve valve 19 and the valve body 18 on the other and improves system sensitivity.
  • ports 23 and 24 in the annular sleeve valve 19 are drilled in a manner that opening of the port passage is gradual.
  • Operating lever 30 located conveniently for the driver is used for both position and draft control working of the threepoint linkage and for working single-acting external hydraulic cylinders.
  • the complete operating range BE of operating lever on section 31 is subdivided into three working ranges; AB for automatic position control where position A is for transport when working in position control, range AF for external hydraulics and range FE for automatic draft control where position F is the transport position when working in automatic draft control.
  • Adjustable stops 32 and 33 are provided on sector 31 for defining the working limits of the operating lever 30.
  • Operating lever 30 carries profile cam 34 and side cam 35 on its axis. Cam 34 through pivoted link 36 actuates the annular sleeve valve 19. The use of side cam 35 is explained subsequently.
  • the draft feedback consists of the already mentioned draft sensor spring assembly 9 wherein the control spring 37 measures the magnitude and direction of the forces in upper link 7.
  • draft actuating abutment rod 39 actuated by abutment 38 projects out and its longitudinal position is dependent upon the compressive or tensile forces in the upper link 7.
  • Feedback from draft actuating abutment rod 39 operates draft radial arm 41 through four-bar linkage 40.
  • the position feedback signal obtained from cam 10 on lift shaft 3 operates position radial arm 44 through roller 43 on four-bar linkage 42.
  • Springs 45 and 46 are provided for the four-bar linkages and 42. Springs and 46 are provided for the four bar linkages 40 and 42 respectively to keep contact with their respective feedback units.
  • Central cam spindle 47 also has central cam 48 mounted freely on it between radial arms 41 and 44. Compression spring 49 fitted between position radial arm 44 and central cam 48 urges the latter towards draft radial arm 41.
  • Central cam 48 carries with it pin 50 fitted to plunger 51, slot 52 in spindle 47 permitting axial movement to the central cam 48 on the spindle 47 in spite of pin 50. Integral groove 53 on central cam 48 permits its free rotation on spindle 47 in spite of pin 50.
  • cap 54 loaded by compression spring 55.
  • Lever 56 actuated by side cam 35, actuates plunger 51 through cap 54 and spring 55, the spring and cap arrangement ensuring contact with end of lever 56, the spring providing a give should forward motion of plunger 51 be restrained.
  • Circlip 57 provides the abutment for position are 44 against spring forces.
  • Pins 58 and 59 projecting on opposite sides of central cam 48 engage into either a slot in the draft radial arm 41 or in the position radial arm 44 depending upon the axial position of the central cam 48.
  • Pin 60 on central cam 48 is arranged to lie in the rotational path of draft radial arm 41 irrespective of the axial position of central cam 48.
  • Central cam 48 actuates spool valve 20 through hinged lever 61, contact between lever 61, contact between lever 61 and cam being retained by spring 29 in control valve 13.
  • Spool valve 62 urged by spring 63 is provided for effecting release of system pressure during overloads and is limited to the neutral position by a stop when it blocks discharge port 64.
  • Ratchet 65 on spool valve 62 can be actuated forward by pawl 66, the pawl-ratchet arrangement providing slip in reverse direction.
  • Pawl 66 is hinged on lever 36 and the lower end of the pawl rests against abutment 68 on lever 67, which runs parallel to lever 36 and on the same hinge point and is spring loaded into contact with cam 34. Corresponding points on levers 67 and 36 therefore have the same movement when under the action of the operating cam 34.
  • the pawl 66 will be actuated downwards when its lower end rests against abutment 68 and lever 36 is actuated forwards, there being downward movement only when there is relative movement between levers 36 and 67. Movement of lever 36 forward separately is caused by abutment 69 on lower 61 coming into contact after a predetermined gap with lever 36, at which stage there is no movement of lever 67 which remains in contact with cam 34 by spring 70. Once the pawl 66 has been actuated downwards into engagement with ratchet 65 on spool valve 20 any further movement of lever 61 causes the spool valve 62 to move forward and open discharge port 64 to sump 12.
  • lever 67 of FIGS. 1 to 7 which runs parallel to lever 36 is eliminated.
  • a differently shaped pawl 66 is actuated downwards by a pin 68a on an extension of lever 61 engaging into a slot in pawl 66.
  • Pawl 66 is actuated downwards when carrying the pawl is stationary and there is any forward motion of lever 61 due to increasing draft forces.
  • any further forward motion of lever 61 causes the forward action of the spool valve 62 to open discharge port 64 to sump 12.
  • Forward motion of lever 36 when actuated by lever 61 is permitted by roller 71 lifting of cam 34 as in the previous system.
  • the spring arrangement on plunger 51 provides a give allowing the movement of the operating lever 30 inspite of obstruction to the movement of the central cam 48. Since the position radial arm 44 is rotating anticlockwise with the lifting of the implement, the slot ultimately comes in line with pin 59, when under the action of spring 49, pin 59 and thereby the central cam 48 comes into engagement with position radial arm 44. Thereafter the movement of the central cam 48 comes under central of the position arm 44 and the position control feed back ensures return of the annular sleeve valve 19 to its neutral/hold position'when the implement 8 has risen to the transport position irrespective of the varying weights of implements.
  • lever 67 Since lever 67 remains stationary, relative movement occurs between levers 36 and 67, causing pawl 66 to drop into engagement with ratchet 65 and any further movement of lever 61 causes the opening of the hydraulic circuit to the sump in the manner described earlier which relieves implement weight transfer on to the rear wheels which consequently start spinning. This spin can be noticed by the driver, who can then reverse out of the obstruction. This wheel spin also prevents excessive rearing forces on the tractor which may cause it to overturn.
  • VISUAL CONTROL OF EXTERNAL SINGLE-ACTION RAMS Zone AE on the operating lever sector 31 is used for visual control of single-acting external rams.
  • the drop in the profile of the operating cam 34 moves annular sleeve valve 19 in the direction S1, opening port 23 and hence the pump suction to sump 12, and the pump 11 starts delivering high-pressure fluid.
  • Piston 2 being already at the end of its travel and prevented from further movement by the lift shaft 3 coming against a stop, high-pressure oil flows to lift the external ram and the extent of lift can be visually adjusted by the operator.
  • operating lever 30 When the ram has reached the desired height, operating lever 30 is brought into position F, when the pump suction is closed and the spool valve 20/annular sleeve valve 19 combination is in its neutral or hold position. For lowering the ram, operating lever 30 is moved into zone FE, when port 24 in annular sleeve valve 19 is opened and the ram lowers under the effect of gravity.
  • variable-orifice response control valve 17 operated by lever 72.
  • Response control is only operative when the implement 8 has to lower down into the soil, when the oil exhausting from the hydraulic cylinder 1 is made to fiow through the variable orifice.
  • Provisions are available in the system for effecting various adjustments to ensure satisfactory preparation.
  • a control mechanism for the regulation of a hydraulic circuit in tractors for controlling the movement and working of mounted implements attached to a three-point linkage comprising a valve mechanism comprised of at least a first and second control valve controlling the working of the said hydraulic circuit, said second valve disposed within said first control valve, a selection and operational control means for selecting and controlling draftand position-working of the said implement, a draft-sensing means operatively connected to said implement, position-sensing means operatively connected to said implement, and a responsive means arranged to receive an actuation movement from said implement through said draft-sensing means and position-sensing means, said responsive means also arranged to receive an actuation from said selection and operational control means, said responsive means comprising a shaft an actuator rotatably mounted on said shaft.
  • a position member rotatably mounted on said shaft, and arranged to be actuated by said position-sensing means
  • a draft member rotatably mounted on said shaft and arranged to be actuated by said draft-sensing means
  • said actuator mounted between said draft member and position member and arranged for engagement with either said position member or draft member upon being actuated by said selection and operational control means, and said actuator being arranged to actuate one of said first and second control valves in response to its engagement with either said position member or draft member.
  • a control mechanism as claimed in claim 4 wherein two first pins extending from said cam on the side thereof of the said draft radial arm and one second pin extending from said cam on the side thereof said position radial arm, and spring means urging said cam toward said draft radial arm to maintain engagement of one said first pin on said draft radial arm.
  • valve mechanism includes a third valve operative during overload on said implement and capable of receiving an actuation from said responsive means, and said selection and operational means controlling the actuation of said third valve.
  • valve mechanism comprises a valve body, said first valve being an annular sleeve valve and cooperating with said second valve and said valve body.
  • a control mechanism as claimed in claim 16 wherein spring means being arranged for urging said first and second valves into contact with the respective said first and second levers, and means provided for oscillating said first valve in its entire sliding range.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Soil Sciences (AREA)
  • Environmental Sciences (AREA)
  • Lifting Devices For Agricultural Implements (AREA)
US822252A 1968-07-29 1969-05-06 Hydraulic control system for agricultural implements Expired - Lifetime US3613798A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3732933A (en) * 1971-06-11 1973-05-15 Ford Motor Co Tractor hydraulic lift system
US20100071919A1 (en) * 2008-09-19 2010-03-25 Norman Everett Muzzy Mechanical hitch control unit
WO2012167258A1 (en) * 2011-06-03 2012-12-06 Precision Planting, Inc. Agricultural toolbar apparatus, systems, and methods
US11078645B2 (en) * 2018-03-29 2021-08-03 Kobelco Construction Machinery Co., Ltd. Slewing-type working machine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ZA802501B (en) * 1979-05-09 1981-04-29 Massey Ferguson Services Nv Tractor hydraulic control systems
DE2949335A1 (de) * 1979-12-07 1981-06-11 Bucher-Guyer AG Maschinenfabrik, Niederweningen, Zürich Selbsttaetige aushebeeinrichtung fuer ein landwirtschaftliches geraet, insbesondere ein maehwerk

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2608954A (en) * 1948-02-26 1952-09-02 Jr Horace C Hogan Hydraulic control valve with automatic follow-up
US2799251A (en) * 1954-01-18 1957-07-16 Bob G Newgen Tractor hitch control device
US2921638A (en) * 1955-06-20 1960-01-19 Deere & Co Selective load and position control for agricultural tractor
US3142342A (en) * 1961-08-14 1964-07-28 Int Harvester Co Flow control compensator
US3203176A (en) * 1962-08-23 1965-08-31 Gen Motors Corp Engine governor
US3489224A (en) * 1966-11-01 1970-01-13 Massey Ferguson Inc Tractor hydraulic control system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2608954A (en) * 1948-02-26 1952-09-02 Jr Horace C Hogan Hydraulic control valve with automatic follow-up
US2799251A (en) * 1954-01-18 1957-07-16 Bob G Newgen Tractor hitch control device
US2921638A (en) * 1955-06-20 1960-01-19 Deere & Co Selective load and position control for agricultural tractor
US3142342A (en) * 1961-08-14 1964-07-28 Int Harvester Co Flow control compensator
US3203176A (en) * 1962-08-23 1965-08-31 Gen Motors Corp Engine governor
US3489224A (en) * 1966-11-01 1970-01-13 Massey Ferguson Inc Tractor hydraulic control system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3732933A (en) * 1971-06-11 1973-05-15 Ford Motor Co Tractor hydraulic lift system
US20100071919A1 (en) * 2008-09-19 2010-03-25 Norman Everett Muzzy Mechanical hitch control unit
US7798241B2 (en) * 2008-09-19 2010-09-21 Deere & Company Mechanical hitch control unit
WO2012167258A1 (en) * 2011-06-03 2012-12-06 Precision Planting, Inc. Agricultural toolbar apparatus, systems, and methods
US9320190B2 (en) 2011-06-03 2016-04-26 Precision Planting Llc Agricultural toolbar apparatus, systems and methods
US9961822B2 (en) * 2011-06-03 2018-05-08 Precision Planting Llc Agricultural toolbar apparatus, systems and methods
US10765054B2 (en) 2011-06-03 2020-09-08 Precision Planting Llc Agricultural toolbar apparatus, systems and methods
US11078645B2 (en) * 2018-03-29 2021-08-03 Kobelco Construction Machinery Co., Ltd. Slewing-type working machine

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