United States Patent
`Greer et a].
`
`[19]
`
`5,467,541
`[11] Patent Number:
`
` [45] Date of Patent: Nov. 21, 1995
`
`
`|||l|||||||||||l|Illlllllll||||||l|l|||||l|||||||||||||l||||l|||||l||||||||
`USOOS467541A
`
`[54]
`
`[75]
`
`[73]
`
`[21]
`
`[22]
`
`[86]
`
`[87]
`
`[51]
`[52]
`[58]
`
`[56]
`
`ELECTRONIC IMPLEMENT CONTROL
`
`Inventors : Robert D. Greer, Peoria; Daniel E.
`Henderson, Washington; Javad
`Hosseini; Noel J. Rytter, both of
`Peoria; Gerald P. Simmons, Morton,
`all of 111.
`
`4,377,043
`4,844,685
`4,864,746
`5,000,650
`5,046,312
`5,052,883
`5,083,894
`
`........................... 414/699 X
`3/1983 Inui et a1.
`
`7/1989 Sagaser ........
`414/699 X
`......... 37/103
`9/1989 Fukumoto
`3/1991 Brewer et a1.
`.. 414/699
`9/1991 Tsuda et a1.
`60/493
`10/1991 Morita et a1.
`.. 414/700
`1/1992 lkari et a1.
`.............................. 414/700
`
`
`
`.....
`
`Assignee: Caterpillar Inc., Peoria, 111.
`
`Appl. No.:
`
`30,286
`
`PCT Filed:
`PCT No.:
`
`Sep. 26, 1991
`PCT/US91/07004
`
`§ 371 Date:
`
`Sep. 26, 1991
`
`§ 102(c) Date: Sep. 26, 1991
`PCT Pub. No.: WO93/06313
`
`Int. Cl.“5
`US. Cl.
`
`PCT Pub. Date: Apr. 1, 1993
`....................................................... G05D 1I02
`........................ 37l348; 414/699; 364/424.07
`Field of Search ............................... 37/348; 414/699;
`74/540; 172/2; 364/424.07
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3,782,248
`3,836,032
`4,011,959
`4,141,258
`
`1/1974 Fuzzell ................................ 414/699 X
`9/1974 Geier .................. 214/764
`
`3/1977 Papasiden's
`. 414/699
`2/1979 Waller ...................................... 74/540
`
`FOREIGN PATENT DOCUMENTS
`
`0125991
`0362394
`2633987
`WO90/02230
`
`11/1984 European Pat. Off. .
`4/1990 European Pat. Off. .
`1/1990 France .
`3/1990 WIPO .
`
`Primary Examiner—Randolph A. Reese
`Assistant Examiner——Victor Batson
`Attorney, Agent, or Firm—Steven R. Janda; James R. Yee
`
`[57]
`
`ABSTRACT
`
`Vehicles (12) having implements (14) are typically used to
`perform repetitive functions in work cycles. Advanta—
`geously, such vehicles (12) include control systems (10) for
`maintaining a control lever (26) in a predetermined position
`until an associated work cycle function is completed. The
`subject control (10) includes a rocker bar (46) connected to
`the control lever (26) and a solenoid (50) having an actuator
`rod (52) disposed adjacent the rocker bar (46). The control
`(10) energizes the solenoid (50) to hold the control lever (26)
`in the predetermined position in response to a position of the
`implement (14), a position of the control lever (26), and a
`desired kickout position.
`
`15 Claims, 3 Drawing Sheets
`
`
`
`74
`
`CONTROL
`CONTROL
`ELECTROHYDRAUIJC
`IMPLEMENT
`
`VALVES
`
`78
`
`
`
`KICKOUT
`CYLINDER
`POSITION
`EXTENSION
`SELECTOR
`SENSOR
`
`
`
`
`
`Page 1
`
`of10
`
`CATERPILLAR EXHIBIT 1 1 1 1
`
`Page 1 of 10
`
`CATERPILLAR EXHIBIT 1111
`
`

`

`US. Patent
`
`Nov. 21, 1995
`
`Sheet 1 of 3
`
`5,467,541
`
`
`
`Page 2 of 10
`
`Page 2 of 10
`
`

`

`US. Patent
`
`Nov. 21, 1995’
`
`Sheet 2 of 3
`
`5,467,541
`
`26
`
` E—E—
`
`44
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`Page 3 0f 10
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`Page 3 of 10
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`

`

`US. Patent
`
`Nov. 21, 1995
`
`Sheet 3 of 3
`
`5,467,541
`
`
`
`ELECTROHYDRAULIC
`VALVES
`
`78
`
`76
`
`CONTROL
`
`IMPLEMENT
`CONTROL
`
`70
`
`74
`
`KICKOUT
`POSITION
`SELECTOR
`
`CYLINDER
`EXTENSION
`SENSOR
`
`Page 4 of 10
`
`Page 4 of 10
`
`

`

`1
`ELECTRONIC IMPLEMENT CONTROL
`
`TECHNICAL FIELD
`
`5,467,541
`
`2
`
`This invention relates generally to levers for controlling
`work vehicle implements, and more particularly, to detent
`mechanisms for maintaining control levers in a predeter-
`mined position.
`
`BACKGROUND ART
`
`Vehicles such as wheel type loaders include work imple-
`ments capable of being moved through a number of posi-
`tions during a work cycle. Such implements typically
`include buckets, forks, and other material handling appara-
`tus. The typical work cycle associated with a bucket includes
`positioning the bucket and associated lift arm in a digging
`position for filling the bucket with material, a rackback
`position, a raised position, and a dumping position for
`removing material from the bucket.
`Control levers are mounted at the operator’s station and
`are connected to a hydraulic circuit for moving the bucket
`and/or lift arms. The operator must manually move the
`control levers to open and close hydraulic valves which in
`turn cause the implement to move. For example, if the lift
`arms are to be raised, the operator moves the control lever
`associated with the lift arm hydraulic circuit to a position at
`which a hydraulic valve causes pressurized fluid to flow to
`the rod end of a lift cylinder thus causing the lift arms to rise.
`The operator must manually hold the hydraulic valve open
`with the control lever until the lift arms reach the desired
`height. When the operator returns the control lever to a
`neutral position, the hydraulic valve closes and pressurized
`fluid no longer flows to the lift cylinder.
`To perform a work cycle in the most efficient manner, the
`operator must steer the vehicle while simultaneously oper-
`ating both the lift arm control lever and the bucket control
`lever. Such operation can be tiresome and diflicult, particu-
`larly for inexperienced operators.
`However, since the implement is moved through the same
`positions each time the work cycle is repeated, control
`systems can be included to automate some of the work cycle
`functions thus reducing the operator’s work load. Such
`control systems often provide predetermined positions for
`the vehicle implements which are associated with the above
`listed work cycle functions. When the operator moves a
`control lever beyond a preselected position at which the
`associated hydraulic valve is open, detents hold the control
`lever in that position. The detent continues to hold the
`control lever in this position until the lift arm or bucket
`reaches the predetermined position. When the control sys-
`tem senses that the implement has reached the predeter-
`mined position, the control system releases the detent. Since
`the control levers are typically spring biased towards a
`neutral position at which the hydraulic valve is closed, the
`control lever returns to the neutral position and the move-
`ment of the lift arm or bucket is stopped when the detent is
`released. Once the control
`lever is moved beyond the
`predetermined position, the control system allows the opera-
`tor to release the control lever and concentrate on the next
`function to be performed.
`Many such devices have been developed. One such
`device is described in US Pat. No. 4,141,258, issued to
`Walzer on Feb. 27, 1979. Walzer discloses a mechanical
`detent system which includes a roller that is spring biased
`toward an engaged position with respect to a notch on the
`control lever. A solenoid is provided for controllably moving
`
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`Page 5 of 10
`
`the roller in a direction away from the engaged position and
`a lost-motion slot
`is included to allow the operator to
`manually release the control lever from the detent position.
`While this arrangement adequately performs the necessary
`operations, it includes a large number of moving parts which
`increase maintenance and warehousing space.
`Another detent mechanism is described in US. Pat. No.
`3,915,325 issued to Lark et al. on Oct. 28, 1975. This
`mechanism utilizes electromagnets to hold the control lever
`in the desired position. Potentiometers are connected to the
`implement and to a mechanism for setting the desired
`implement position. When the potentiometers are producing
`substantially different signals, the electromagnet is ener-
`gized. If the control lever is moved such that a latching
`means is relatively close to the electromagnet,
`then the
`electromagnet will attract the latching means with suflicient
`force to hold the control lever in that position. When the
`implement reaches the desired position, the two potentiom—
`eters produce nearly identical signals which causes the
`electromagnet to be deenergized. This in turn causes the
`control lever to return to the neutral position. While this
`arrangement reduces the number of moving parts, the elec-
`tromagnets are energized whenever the implement is not in
`the desired position. For example, the detent mechanism is
`activated in situations in which the operator only moves the
`control lever a small amount and has no desire to put the
`control lever into the detent position. Furthermore, if the
`implement is above the preselected lifted position and the
`operator moves the control lever to further raise the imple-
`ment, the electromagnet will also be energized. This results
`in an undue waste of electrical energy and does not accu-
`rately reflect the operator’s desired operation.
`The present invention is directed to overcoming one or
`more of the problems set forth above.
`
`DISCLOSURE OF THE INVENTION
`
`The invention avoids the disadvantages of known control
`lever detent mechanisms and provides an electronic imple-
`ment control
`that controllably actuates and deactuates a
`detent in a manner which reflects the operator’s desired
`implement functions.
`In one aspect of the present invention, an apparatus for
`controlling an implement connected to a work vehicle and
`movable to and between a plurality of positions is provided.
`A control lever is pivotably connected to a mounting bracket
`on the vehicle. A rocker bar is also connected to the control
`lever and is in contact with the actuator rod of a solenoid. A
`device is provided for producing a control signal in response
`to movement of the control lever. A resilient member is
`
`included for urging the actuator rod toward a detent position.
`A detent control actuates and deactuates the solenoid in
`response to the control signal and the position of the
`implement.
`The invention also includes other features and advantages
`which will become apparent from a more detailed study of
`the drawings and specification.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`For a better understanding of the present invention, ref-
`erence may be made to the accompanying drawings, in
`which:
`
`FIG. 1 is a side view of a loader vehicle embodying the
`invention;
`
`Page 5 of 10
`
`

`

`3
`
`4
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`5,467,541
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`FIG. 2 is a diagrammatic view of the control lever, rocker
`bar, and shaft arrangement; and
`FIG. 3 is a schematic view of an embodiment of the
`invention including a reduced view of the control lever,
`rocker bar, and shaft arrangement shown in FIG. 2.
`
`BEST MODE FOR CARRYING OUT THE
`INVENTION
`
`In FIG. 1, an implement control system is illustrated
`generally by the number 10. Although FIG. 1 shows a wheel
`type loader vehicle 12 having an implement 14 in the form
`of a bucket, the present invention is equally applicable to
`vehicles such as track type loaders, hydraulic excavators,
`and other vehicles having hydraulically operated imple—
`ments. The implement 14 is connected to a lift arm assembly
`16, which is pivotally actuated by two hydraulic lift cylin-
`ders 18 (only one of which is shown) about a pair of lift arm
`pivot pins 20 (only one shown) attached to the vehicle
`frame. The implement 14 is pivotally mounted to the lift
`arms 16 and is connected to a pair of implement tilt cylinders
`22 (only one shown) via a tilt linkage 24. The lift and tilt
`cylinders 18,22 are connected to a hydraulic circuit (not
`shown) and are extendable and retractable in response to
`movement of lift and tilt control levers 26 mounted at the
`vehicle operator’s station 28.
`While the operation of an embodiment of the invention
`will only be described in connection with the control lever
`26 associated with the lift cylinders 18, it should be appre—
`ciated that the embodiment associated with the tilt cylinders
`22 operates in a similar manner. Referring now to FIG. 2, the
`control lever 26 is shown. A bracket 30 is connected to the
`vehicle 12 and includes a pair of holes through which a
`control shaft 32 extends. Bearings can advantageously be
`connected to and between the bracket 30 and the control
`shaft 32 to facilitate ease of rotational motion of the control
`shaft 32 within the bracket holes. The control lever 26 is
`connected to the control shaft 32 through a pivot bolt 34 and
`a coupler 36. In the preferred embodiment, the control lever
`26 and the pivot bolt 34 both include threaded portions
`which are threadably engaged with a connecting nut 38. The
`control shaft 32 extends through the head of the pivot bolt
`34 which includes a hole having a diameter that is slightly
`larger than the outer diameter of the control shaft 32.
`Preferably,
`there is a precision running fit between the
`control shaft 32 and the pivot bolt 34. Such an arrangement
`provides a common center of rotation for the control shaft 32
`and the control lever 26.
`
`The coupler 36 includes an upper portion 40 and a lower
`portion 42. The upper portion 40 is disposed adjacent the
`connecting nut 38 and includes an orifice through which the
`pivot bolt 34 extends. The control shaft 32 engages the
`coupler 36 and preferably extends through the lower portion
`42 of the coupler 36. The coupler 36 is held in position with
`respect to the control lever 26 by being compressed between
`the connecting nut 38 and the rocker bar 46. A first gear 44
`is attached to the control shaft 32 such that the first gear 44
`is angularly displaced an amount being substantially equiva-
`lent to the angular displacement of the control shaft 32 and
`control lever 26.
`
`A rocker bar 46 is connected to and between the pivot bolt
`34 and the connecting nut 38. In the preferred embodiment,
`the rocker bar 46 is threadably engaged with the pivot bolt
`34 and includes a recessed portion substantially equidistant
`from the two distal ends of the rocker bar 46. The recessed
`portion is configured to allow the rocker bar 46 to pivot
`
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`through a predetermined range of motion without coming in
`contact with the bracket 30.
`'
`
`Referring now to FIG. 3, the control lever, rocker bar, and
`control shaft arrangement is shown connected to the vehicle
`12 via a mounting plate 48. While the bracket 30 is prefer-
`ably bolted to the mounting plate 48, nearly any means of
`fixedly connecting the bracket 30 and the mounting plate 48
`would be satisfactory.
`A pair of solenoids 50 are also connected to the mounting
`plate 48 in locations adjacent the distal ends of the rocker bar
`46. While solenoids 50 are included in the preferred embodi-
`ment, any means for controllably moving a rod in response
`to an electrical signal would be operable in connection with
`the invention. The solenoids 50 each include a winding (not
`shown) that is in electromagnetic communication with an
`actuator rod 52.
`
`Each actuator rod 52 is disposed in an orifice extending
`substantially through the respective solenoid 50 and is
`slidably movable within the orifice. The actuator rod 52
`includes a first end 54 disposed adjacent the rocker bar 46
`and a second end 56 having a flange and being disposed
`within a spring box 58. The spring box 58 includes a resilient
`member 60, preferably a compression spring, that is located
`adjacent the flange on the second end 56 and urges the
`actuator rod 52 in a direction toward the rocker bar 46. In
`this way, the actuator rod 52 is spring biased toward the
`rocker bar 46 such that the force exerted by the resilient
`member 60 is transferred to the rocker bar 46 and the control
`lever 26 via the actuator rod 52. Since each resilient member
`60 has a spring constant that is substantially equivalent to
`that of the other resilient member 60, the control lever 26 is
`effectively spring biased in a neutral position. When the
`operator pivots the control lever 26 in either direction about
`the control shaft 32, the resilient members 60 resist that
`motion and return the control lever 26 to the neutral position
`when the operator releases the control lever 26. The stilfness
`of the resilient members 60 is chosen to provide an optimal
`operator feel.
`
`When the solenoid winding is energized, the resulting
`electromagnetic field urges the actuator rod 52 toward the
`rocker bar 46 in a manner well-known in the art. Thus, force
`in addition to that of the resilient member 60 can be
`controllably applied to the rocker bar 46 by energizing the
`solenoid winding.
`A means 62 for producing a control signal is connected to
`and between the vehicle 12 and the first gear 44. The control
`signal producing means 62 advantageously includes a rotary
`potentiometer 66 and a second gear 64 that is adapted to
`engage the first gear 44. The relative sizes of the first and
`second gears 44,64 are chosen such that as the control lever
`26, and consequently the first gear 44, moves through the
`predetermined range of motion, the second gear 64 is moved
`through a range determined by the rotational limits of the
`rotary potentiometer 66. In the preferred embodiment, the
`rotary potentiometer 66 produces a pulse width modulated
`signal having a duty cycle that is dependent upon the angular
`position of the second gear 64 and is variable from 5% to
`95%. The second gear 64 is positioned with respect to the
`first gear 44 and the rotary potentiometer 66 such that the
`duty cycle of the control signal is at approximately 50%
`when the control lever 26 is in the neutral position. When the
`control lever 26 is pivoted in one direction from the neutral
`position, the duty cycle of the control signal is less than
`50%, and when the control lever 26 is pivoted in the other
`direction, the duty cycle is greater than 50%. While only a
`rotary potentiometer capable of producing a pulse width
`
`Page 6 of 10
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`Page 6 of 10
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`

`

`5
`
`6
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`5,467,541
`
`modulated signal is described, it should be appreciated that
`any device capable of producing an electrical signal
`in
`response to the pivotal motion of the control lever 26 would
`be operable with the instant invention.
`A control system 68 includes an implement control 70 and
`a detent control 72 and is in electrical communication with
`the solenoids 50 and the control signal producing means 62.
`The implement control 70 delivers an implement signal to
`the electrohydraulic valves 76 to controllably extend and
`retract the lift cylinders 18 in response to the duty cycle of
`the control signal and hence the position of the control lever
`26. The detent control 72 is provided to controllably ener-
`gize and deenergize the solenoids 50.
`The detent control 72 compares the duty cycle of the
`control signal to values corresponding to the control signal
`duty cycles when the control lever 26 is at predetermined
`raise and lower detent positions. If the duty cycle is less than
`or equal to the predetermined duty cycle for the control lever
`26 being at the lower detent position, the detent control 72
`actuates the lower detent solenoid to hold the control lever
`in that position until the lift arms are lowered to a prese-
`lected return to dig position. However, if the implement is
`already below the return to dig position, the solenoid 50 will
`not be actuated. If the duty cycle is greater than or equal to
`the predetermined duty cycle for the control lever 26 being
`at the raise detent position, the detent control 72 actuates the
`raise detent solenoid to hold the control lever 26 in that
`position until the lift arms are raised to a preselected dump
`position. However, if the implement is already above the
`dump position, the solenoid 50 will not be actuated.
`A cylinder extension sensor 74 is connected to and
`between at least one of the two lift cylinders 18 and the
`control system 68 and produces a cylinder extension signal
`representative of the position of a cylinder rod within the
`cylinder 18. In the preferred embodiment,
`the cylinder
`extension sensor 74 is a radio frequency (RF) sensor dis—
`posed within the cylinder, but a sensor located external to the
`cylinder and performing a similar function would also be
`operable in connection with the control system 68. Likewise,
`a rotational sensor disposed adjacent the lift arm pivot pins
`20 and which produces a signal in response to the angular
`position of the lift arm assembly 16 with respect to the
`vehicle 12 would also be operable with the instant invention.
`A kickout position selector 76 is provided to allow the
`operator to select the positions of the lift arm assembly 16
`corresponding to the desired positions of the implement 14
`during the various work cycle functions and at which the
`detents are to be released. In the preferred embodiment, the
`kickout position selector 76 includes a push-button switch or
`other appropriate device (not shown) for producing a desired
`kickout signal in response to the operator’s selections of
`desired kickout positions.
`In response to receiving the desired kickout signal, the
`detent control 72 stores the present cylinder extension signal
`in memory. In the preferred embodiment, the cylinder exten-
`sion signal is stored in memory at an upper kickout address
`if the signal is greater than a predetermined magnitude and
`is stored at a lower kickout address if the signal is less than
`the predetermined magnitude.
`An electrohydraulic valve 78 is connected to and between
`the control system 68 and the lift cylinders 18. The electro—
`hydraulic valve 78 is adapted to controllably direct pressur-
`ized fluid to the lift cylinders 18 in response to an implement
`signal that is produced by the implement control 70. The
`implement control 70 therefore causes the lift cylinders to
`extend and retract via operation of the electrohydraulic valve
`
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`the implement control 70 sends a raise
`78. Preferably,
`implement signal to the electrohydraulic valve when the
`duty cycle of the control signal is greater than 50% and
`sends a lower implement signal to the electrohydraulic valve
`in response to the duty cycle of the control signal being less
`than 50%. When the control signal duty cycle is approxi-
`mately 50%, the implement control 70 causes the electro-
`hydraulic valve to maintain the lift arm assembly in its
`present position with respect to the vehicle.
`When the control lever 26 is moved to a position beyond
`the predetermined raise detent position, the detent control 72
`compares the cylinder extension signal stored in the upper
`kickout address to the present cylinder extension signal
`being produced by the cylinder extension sensor. If the
`comparison between the cylinder extension signals indicates
`that the lift arm assembly 16 is below the preselected dump
`height, the detent control 72 actuates the appropriate sole-
`noid 50 to maintain the control lever in the raise detent
`
`position. If the cylinder extension signal comparison indi-
`cates that the lift arm assembly 16 is already at or above the
`preselected dump height, the detent control 72 does not
`actuate either of the solenoids 50.
`
`As the lift arm assembly 16 rises in response to the
`implement signal from the implement control 70, the detent
`control 72 continues to compare the present cylinder exten-
`sion signal to the signal stored in the upper kickout address.
`When the cylinder extension signal is substantially equal to
`that stored in the upper kickout address, the detent control 72
`deactuates the solenoid 50, the control lever 26 returns to the
`neutral position, and the implement "control 70 returns the
`electrohydraulic valve 78 to a closed position at which the
`lift cylinders 18 are maintained in their present position.
`To lower the lift arm assembly 16 to the return to dig
`position,
`the operator moves the control
`lever 26 to a
`position beyond the predetermined lower detent position.
`The control system 68 receives the control signal from the
`rotary potentiometer 66 and the implement control 70
`responsively sends an implement signal to the electrohy—
`draulic valves 78 to retract the lift cylinders 18. The detent
`control 72 compares the cylinder extension signal stored in
`the lower kickout address to the present cylinder extension
`signal being produced by the cylinder extension sensor. If
`the comparison between the cylinder extension signals indi-
`cates that the lift arm assembly 16 is above the preselected
`return, to dig height,
`the detent control 72 actuates the
`appropriate solenoid 50 to maintain the control lever in the
`lower detent position. If the cylinder extension signal com-
`parison indicates that the lift arm assembly 16 is already
`below the preselected return to dig height, the detent control
`72 does not actuate either of the solenoids 50.
`
`As the lift arm assembly 16 is lowered in response to the
`implement signal from the implement control, the detent
`control 72 continues to compare the present cylinder exten-
`sion signal to the signal stored in the lower kickout address.
`When the cylinder extension signal is substantially equal to
`that stored in the lower kickout address, the detent control 72
`deactuates the solenoid 50, the control lever 26 returns to the
`neutral position, and the implement control returns the
`electrohydraulic valve 78 to a closed position at which the
`lift cylinders 18 are maintained in their present position.
`In an alternative embodiment,
`the detent control 72
`returns the control lever 26 to the neutral position before the
`lift arm assembly 16 reaches the preselected dump or return
`to dig height. In this case, the implement control 70 con
`tinues to produce the implement signal even though the
`rotary potentiometer 66 is no longer producing the control
`
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`7
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`8
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`5,467,541
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`lever 26 returns to the neutral
`signal. After the control
`position, the implement control 70 modulates the implement
`signal to reduce the velocity of the lift arm assembly 16
`before the electrohydraulic valve 78 is completely closed.
`Stresses on the hydraulic system and operator discomfort are
`therefore reduced by progressively reducing the velocity of
`the lift arm assembly 16 over a substantial distance.
`To manually return the control lever to the neutral posi-
`tion, the operator exerts force on the control lever 26 toward
`the neutral position. The exerted force must be greater than
`the sum of forces being exerted by the resilient members and
`the actuated solenoid. As the control lever moves a short
`distance toward the neutral position, the detent control 72
`deactuates the solenoid 50 in response to the control signal
`having a duty cycle substantially closer to the duty cycle
`corresponding to the neutral position.
`
`Industrial Applicability
`
`Vehicles such as wheel type loaders are typically operated
`in work cycles in which a lift arm assembly 16 is repetitively
`moved to and between a raised position and a lowered
`position. The raised and lowered positions are dependent
`upon a number of parameters which are application specific,
`e.g. the height of the walls of a truck being loaded and the
`location of the material to be loaded. The instant invention
`
`is particularly useful to controllably move the implement to
`and between the raised and lowered positions with relatively .
`little operator attention. While the operation of the instant
`invention is described in connection with a truck loading
`cycle, it should be understood that the invention operates
`analogously when used in any work cycle.
`' The operator pivots the control lever 26 in the appropriate
`direction to raise the lift arms. When the lift arm assembly
`16 reaches the desired dump height, the operator returns the
`control lever 26 to the neutral position and activates the
`kickout position selector 76 which responsively produces
`the desired kickout signal. When the control system 68
`receives the desired kickout signal, the cylinder extension
`signal is stored in memory. Assuming the lift arm assembly
`16 is above the predetermined position, the cylinder exten-
`sion signal
`is stored in the upper kickout address. The
`operator then pivots the control lever 26 in the opposite
`direction to lower the lift arms. When the lift arm assembly
`16 reaches the desired return to dig position, the operator
`returns the control lever 26 to the neutral position and once
`again actuates the kickout position selector 76. Assuming
`the lift arm assembly 16 is below the predetermined posi-
`tion, the cylinder extension signal is stored in the lower
`kickout address.
`
`Following the above initialization process, the operator
`fills the bucket with material and begins the work cycle. If
`the operator does not move the control lever 26 beyond the
`predetemiined raise and lower detent positions, the operator
`extends and retracts the lift cylinders 18 via the implement
`control 70 and electrohydraulic valves 78 in a manual mode.
`However, If the operator pivots the control lever 26 to a
`position beyond the predetermined raise detent position, the
`detent control 72 actuates the appropriate solenoid 50. When
`the cylinder extension signal is substantially equal to that
`stored in the upper kickout address, the detent control 72
`deactuates the solenoid 50, the control lever 26 retums to the
`neutral position, and the electrohydraulic valve 78 returns to
`a closed position at which the lift cylinders 18 are main-
`tained in their present position.
`To lower the lift arm assembly 16 to the return to dig
`position,
`the operator moves the control
`lever 26 to a
`
`5
`
`10
`
`15
`
`20
`
`25
`
`3O
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`position beyond the predetermined lower detent position.
`When the cylinder extension signal is substantially equal to
`that stored in the lower kickout address, the detent control 72
`deactuates the solenoid 50, the control lever 26 returns to the
`neutral position, and the electrohydraulic valve 78 returns to
`a closed position at which the lift cylinders 18 are main-
`tained in their present position.
`To manually return the control lever to the neutral posi-
`tion, the operator exerts force on the control lever 26 toward
`the neutral position. The resulting motion causes the detent
`control 72 to deenergize the appropriate solenoid.
`The typical wheel type loader vehicle includes a control
`lever for the implement tilt hydraulic circuit in addition to
`the above described lever for the lift hydraulic circuit. The
`tilt control lever operates in an analogous fashion and will
`not be further discussed. Likewise, embodiments of the
`instant invention are usable with similar vehicles that per-
`form repetitive functions with hydraulically operated imple-
`ments, such as track type loaders, excavators, and backhoes.
`Similarly, the present invention is also operable with sys-
`tems utilizing other motive means, such as pneumatic sys—
`tems and electrically driven systems.
`Other aspects, objects, and advantages of this invention
`can be obtained from a study of the drawings, the disclosure,
`and the appended claims.
`We claim:
`
`1. An apparatus for controlling an implement connected to
`a work vehicle and movable to and between a plurality of
`positions, comprising:
`means for sensing the position of the implement and
`responsively producing an implement position signal;
`a mounting bracket connected to the vehicle;
`a control lever being pivotably connected to said mount-
`ing bracket and movable between first and second
`positions;
`a rocker bar connected to said control lever;
`means for producing a control signal
`in response to
`movement of the control lever;
`
`a solenoid having an actuator rod being in contact with
`said rocker bar and movable to a detent position in
`response to said solenoid being energized; and
`detent control means for controllably energizing said
`solenoid in response to said control signal having a
`value indicative of the control
`lever being moved
`beyond a detent position and said implement position
`signal being indicative of the implement having a
`predetermined relationship with a set position and
`deenergizing said solenoid in response to the imple-
`ment position signal being indicative of the implement
`having a second predetermined relation with said set
`position.
`2. An apparatus (10), as set forth in claim 1, including:
`an implement control
`(70) for receiving said control
`signal and responsively producing an implement sig-
`nal; and
`
`means (18) for moving the implement (14) in response to
`the implement signal.
`3. An apparatus for controlling an implement connected to
`a work vehicle and movable to and between a plurality of
`positions, comprising:
`means for sensing the position of the implement and
`responsively producing an implement position signal;
`means for selecting a desired kickout position;
`a mounting bracket connected to the vehicle;
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`9
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`10
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`5,467,541
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`a control lever being pivotably connected to said mount-
`ing bracket and movable between first and second
`positions;
`a rocker bar connected to said control lever;
`means for producing a control signal
`in response to
`movement of the control lever;
`
`a solenoid having an actuator rod being in contact with
`said rocker bar and movable to a detent position in
`response to said solenoid being energized;
`a biasing means for urging said actuator rod toward said
`detent position; and
`detent control means for controllably energizing said
`solenoid in response to said control signal h