Abstract:
The present invention is a control arrangement that includes a detent assist assembly for assisting a detent arrangement in holding a control device in a predetermined position. Additionally, the detent assist assembly serves as an actuator for a control valve operative with the control device. Further, the detent assist assembly provides tactile feedback to an operator through the control device. The present invention is a simple and efficient device for providing a detent assist with tactile feedback.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates generally to a magnetic detent arrangement and more particularly to an improved mechanism for assisting the magnetic detent arrangement and for providing tactile feedback to an operator.  
         BACKGROUND  
         [0002]    In many hydraulic and pneumatic systems, control valves are provided for regulating the flow of fluid from a pressurized source to one or more control devices. Control devices are commonly used on machines to provide an input by an operator to perform desired functions on a work machine. Typically, the control devices are movable to a plurality of positions. The control devices are normally spring biased to return to a neutral position when the operator releases the control device. In many work machines, it is well known to provide a detent arrangement to hold the control device in a single position to reduce operator fatigue. There are many common types of detent arrangements that may be utilized for this purpose, including mechanical, magnetic, electromagnet and the like. Many of these detents have proven that they are not sufficient to hold the control device at the desired detented position when the machine is being subjected to rough terrain or the operator inadvertently touches the control device. Therefore, it is desirable to provide either a high force detent arrangement or a mechanism for assisting the detent arrangement that will more effectively hold the control device in the desired detented position. Likewise, it is desirable to provide a tactile feedback to the operator before the detent arrangement is engaged. Upon sensing the tactile feedback, the operator is able to avoid further movement of the control device and the resulting actuation of the detent arrangement. Also, in this manner, the operator will be aware of the location and “feel” of the control device and the resulting function achieved on the work machine.  
           [0003]    U.S. Pat. No. 6,098,481 issued on Aug. 8, 2000 to Rudy V. Mills, et al. discloses a high force detent mechanism that selectively holds a control input lever in any selected position between neutral and its maximum travel in either direction. The high force detent mechanism includes a coil assembly connected to a control input lever and disposed in close proximity to a semi-circular member having a serrated edge defined thereon. An armature of the coil assembly has as first portion in driving contact with the serrated edge and a second enlarged portion having a latching surface disposed adjacent one of the first and second end faces of the coil assembly&#39;s detent coil. The size of the latching surface is larger than the size of the first portion that is in driving contact with the serrated edge. Consequently, the latching force generated between the latching surface and the one face of the detent coil is multiplied several times to create a detent holding force that is larger than the latching force. In this design, the detent holding force is created to increase the effective latching capability of the detent. Accordingly, an operator utilizing the detent mechanism would have to overcome the increased detent holding force in order to move the control lever to the neutral position. Due to the increased detent holding force, this effort may be fatiguing to the operator over extended periods of time. Also, the increased high force detent mechanism does not increase tactile feedback to the operator during movement of the control lever which is useful for assessing when a function of the work machine is changing.  
           [0004]    U.S. Pat. No. 5,566,710 issued on Oct. 22, 1996 to Derek A. Dahlgren, et al. discloses an improved pre-detent tactile feedback assembly for a fluid control valve. The pre-detent tactile feedback assembly includes an elastic member, such as a garter type spring, seated within an annular groove formed in the bore of a plunger valve assembly. When the plunger is moved from an opened to a closed position, a portion of the plunger contacts the elastic member, urging the elastic member outwardly into the groove. The additional force required to urge the elastic member into the groove provides a “feel” force to the control lever. Preferably, the groove is positioned within the bore so that this feel” force is sensed just prior to actuation of an associated detent assembly. In this design, the improved structure effectively increases the force required to move the control lever just prior to engagement of the detent but does not increase the force acting against the detent to assist in holding the detent in a desired detented position.  
           [0005]    The present invention is directed to overcoming one or more of the problems as set forth above.  
         SUMMARY OF THE INVENTION  
         [0006]    In one aspect of the present invention, a detent assist assembly for a detent arrangement comprises a first member with an outer surface that includes a resistance portion. A second member is movable from a neutral position to first and second positions wherein movement to the first position engages the second member with the resistance portion and movement to the second position disengages the second member from the resistance portion. The second member is operative with the resistance portion when in the second position to assist in holding the detent arrangement in a predetermined position.  
           [0007]    In another aspect of the present invention, a control arrangement is disclosed for actuating at least two control valves. The control arrangement comprises a control device that is movable from a neutral position to first and second control positions. The control device has an actuator for actuating one of the control valves when moved to the first control position. A detent arrangement is operative with the control device for holding the control device in the first control position. A detent assist assembly is operative with the control device with means for assisting the detent arrangement in holding the control device in the first control position. The detent assist assembly has an actuator for actuating the other one of the control valves when the control device is moved to the second control position.  
           [0008]    The present invention is a control arrangement that includes a detent assist assembly for assisting a detent arrangement in holding a control device in a predetermined position. Additionally, the detent assist assembly serves as an actuator for a control valve operative with the control device. Further, the detent assist assembly provides tactile feedback to an operator through the control device. The present invention is a simple and efficient device for providing the improved features herein. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a sectional view and diagrammatic representation of a control arrangement incorporating the present invention;  
         [0010]    [0010]FIG. 2 is a sectional view and diagrammatic representation of the control arrangement taken ninety degrees from the view shown in FIG. 1;  
         [0011]    [0011]FIG. 3 is a sectional view and diagrammatic representation of the control arrangement shown in a first rotated position in a first direction;  
         [0012]    [0012]FIG. 4 is a sectional view and diagrammatic representation of the control arrangement shown in a second rotated position in the first direction;  
         [0013]    [0013]FIG. 5 is a sectional view and diagrammatic representation of the control arrangement shown in a rotated position in a second direction;  
         [0014]    [0014]FIG. 6 is a side view of a diagrammatic representation of a control lever assembly incorporated in the control arrangement of FIG. 1; and  
         [0015]    FIGS.  7 - 10  are detailed views of first and second members of a detent assembly incorporated in the control arrangement of FIG. 1. 
     
    
     DETAILED DESCRIPTION  
       [0016]    While the invention is open to various modification and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. However, there is no intent to limit the invention to the particular form disclosed.  
         [0017]    Referring to the drawings, a control arrangement  10  is shown in FIGS.  1 - 5  and includes a control lever assembly  20 . In particular, the control arrangement  10  is used for controlling various work machine implement functions, such as, blade float, blade quick drop, dozer raise, and the like. However, it should be understood that the control arrangement  10  may be used for any suitable application, such as, controlling other work machine functions, recreational vehicles (not shown), video games (not shown) or other suitable devices. The control lever assembly  20  is seen best in FIG. 6 and includes a control device or joystick portion  30  that is connected to a support  40  through a universal coupling  50  for pivotal movement about a pivot  60 . A first control position  64  of the joystick portion  30  is achieved as the joystick portion  30  is pivoted in the direction of arrow  1  shown in FIG. 4. A second control position  66  of the joystick is achieved as the joystick portion  30  is pivoted in the direction of arrow  2  shown in FIG. 5. A plurality of additional control positions (not shown) other than the first and second control positions are achieved via the pivotal movement of the joystick portion  30  about the pivot  60 . The support  40  can be, for example, a component of a pilot valve body  70  or a separate plate in connection with the pilot valve body  70 . The pilot valve body  70  includes a plurality of control valve assemblies, one of which is shown at  75 , disposed therein. The control valve assemblies  75  each have plungers, two of which are shown at  80 , 90  in FIG. 1, that are operative with the joystick portion  30 . The plungers  80 , 90  extend through the support  40  on opposite sides of the universal coupling  50 . Another two plungers, shown at  100 , 110  in FIG. 2, are typically located at ninety degrees from the plungers  80 , 90 . The plungers  80 , 90 , 100 , 110  are spring biased for centering the joystick portion  30  to a neutral position  120  in a well-known manner, as shown in FIGS.  1 - 2 .  
         [0018]    Referring with particularity to FIG. 6, a carrier  200  is mounted with the joystick portion  30  and spaced a predetermined distance from the support  40 . A detent assist assembly  210  is mounted on the carrier  200  in any suitable manner, such as through bolts, one of which is shown at  220 . The detent assist assembly  210  is operative with the joystick portion  30  for movement from a neutral position  212 , shown in FIG. 1, to first and second operating positions  214 , 216  shown in FIGS.  3 - 4 , respectively. Referring to FIGS.  7 - 8 , the detent assist assembly  210  is shown in detail and includes a detent housing  230  having a first planar surface  240 , a second surface  250  with a contact portion  260  opposite the planar surface  240  and a stepped bore  270  therethrough. A biasing spring  280  is positioned within the bore  270 . A detent  290  is slidingly disposed within the bore  270  and includes head and rod end portions  300 , 310 . The spring  280  encircles the rod end portion  310  for abutment against the head end portion  300  so that the detent  290  is capable of movement from a normally extended position to a plurality of positions within the bore  270  upon actuation of the spring  180 . A knife edge  320  is formed on an outer surface  330  of the head end portion  300  and extends beyond a front face  340  of the detent housing  230  in the normally extended position. Means are used for connecting the detent  290  within the detent housing  230  and include a pair of spring pins  350 , 360  that extend through a pair of slots  370 , 375  in the detent housing  230  and into a respective oversized slot  380 , 390  in the head end portion  300  of the detent  290 . The pins  350 , 360  are free to slide within the slots  380 , 390  within the range permitted. Although pins  350 , 360  are used in the preferred embodiment, it should be understood that any suitable connection means may be used such as bolts, rivets, and the like that are extendable from the detent housing  230  and into the slots  380 , 390 .  
         [0019]    Referring specifically to FIGS.  1  &amp;  3 - 5  and, for detail, to FIGS.  9 - 10 , the detent assist assembly  210  further includes an action plate  400  connected with the pilot valve body  70  in any suitable manner, such as through bolts, one of which is shown at  410 . One or more shims  420  may be used between the bolts  410  and the pilot valve body  70  in order to define a predetermined height for the action plate  400 . The action plate  400  is formed in a substantial U-shape and includes a knife edge resistance portion  430 . The knife edge resistance portion  430  is disposed between a lower portion  435  and a bent upper portion  440  and extends forwardly a predetermined length toward the detent housing  230  from an outer surface  450  to an outermost tip  460 . The lower portion  435  of the action plate  400  includes a defined opening  470  therethrough to define the U-shape. A protrusion  480  is defined along the outer surface  450  of the action plate  400  between the knife edge resistance portion  430  and the upper portion  440 .  
         [0020]    Referring to FIGS.  1  &amp;  3 - 5  and, for detail, to FIG. 6, a plunger pin assembly  500  is shown having a pin  510  with a contact end portion  520  and a threaded end portion  530  threaded through the carrier  200  on an opposite side of the universal coupling  50  from the detent assist assembly  210 . The pin  510  is retained on the carrier  200  in any suitable manner, such as by nut  540 .  
         [0021]    A magnetic detent arrangement  542  is mounted on the plunger pin assembly  500  and includes a washer  550  that encompasses the contact end portion  520  of the pin  510  at a beveled, open end portion  560 . The washer  550  is manufactured from any suitable magnetic material, such as steel, and has a planar surface  570  opposite the open end portion  560 . A biasing spring  580  is positioned between the open end portion  560  and the carrier  200  to allow movement of the washer  550  upon actuation of the spring  580 . The planar surface  570  of the washer  550  is spaced a predetermined distance from a magnet  590  when the joystick portion  30  is in the neutral position  120  shown in FIGS.  1 - 2 . The magnet  590  is connected in any suitable manner with the pilot valve body  70  and surrounds a portion of the plunger  90 .  
         [0022]    Referring to FIG. 2, a pair of plunger pins  600 , 610  are located ninety degrees respectively from the detent assist assembly  210  and the plunger pin assembly  500 . The plunger pins  600 , 610  each have a contact end portion  620  and a threaded end portion  630  threaded through the carrier  200  on opposite sides of the universal coupling  50 . The contact end portions  520 , 620  of the plunger pins  600 , 610 , 510 , respectively, and the contact portion  260  of the housing  230  each are axially aligned with a respective plunger  80 , 90 , 100 , 110  in the pilot valve body  70 . The plungers pins  510 , 600 , 610  and the contact portion  260  abut a top surface of the plungers  80 , 90 , 100 , 110 . The plungers  80 , 90  are actuated in response to movement of the joystick portion  30  to a respective control position  64 , 66  about the pivot  60  and respondent action of the plunger pins  510  and the contact portion  260  of the housing  230 . The plungers  100 , 110  are actuated in response to movement of the joystick portion  30  to a respective additional control position (not shown) about the pivot  60  and respondent action of the plunger pins  600 , 610 .  
       INDUSTRIAL APPLICABILITY  
       [0023]    When an operator (not shown) desires to maintain an implement (not shown) in a predetermined function, such as blade float, the joystick portion  30  is moved to a first control position  64 . In this manner, the washer  550  of the magnetic detent arrangement  542  is held against the magnet  590  to engage the control lever assembly  20 . The contact end  520  of the pin  510  actuates the respective control valve plunger  90  in a conventional manner to achieve the blade float implement function. In order to assist the magnetic detent arrangement  542  in holding the joystick portion  30  in the first control position  64 , the detent assist assembly  210  moves cooperatively with the joystick portion  30  to the second operating position  216 .  
         [0024]    During movement of the detent assist assembly  210  to the second operating position  216 , the first operating position  214  is reached when the knife edge  320  of the detent  290  contacts the knife edge resistance portion  430  of the action plate  400 . When the knife edge  320  engages the knife edge resistance portion  430 , a predetermined force is exerted on the spring  280 . Extra force is required by the operator (not shown) to move the joystick portion  30  so that the detent assist assembly  210  moves along the knife edge resistance portion  430  to the outermost tip  460 . During this movement, ever increasing forces are exerted on the spring  280  so that the detent  290  is moved inwardly into the detent housing  230 .  
         [0025]    As the knife edge  320  moves along a path between the knife edge resistance portion  430  and the second operating position  216 , the knife edge  320  is in constant contact with the action plate  400  and the shape of the protrusion  480  is defined. Although the knife edge  320  remains in contact with the protrusion  480 , the knife edge  320  becomes disengaged from the knife edge resistance portion  430  when the second operating position  216  is reached. As the forces on the spring  280  diminish accordingly, the detent  290  moves outwardly toward the upper portion  440  of the action plate  400 . Thereafter, the shape of the protrusion  480  restricts the detent assist assembly  210  from moving from the second operating position  216  to the first operating position  214 . It should be obvious that the shape of the protrusion  480  increases the force needed to move the detent assist assembly  210  from the second operating position  216  to the first operating position  214 . This ability assists the magnetic detent assembly  542  in holding the joystick portion  30  in the first control position  64  during movement of the work machine (not shown) over rough terrain or during operation in heavy applications. Additionally, the likelihood of inadvertent movement of the joystick portion  30  by the operator (not shown) is decreased.  
         [0026]    It should be understood that the joystick portion  30  may be moved to achieve various other functions of the work machine (not shown) when the implement (not shown) is in the blade float function. For instance, the joystick portion  30  may be moved about the pivot  60  to actuate control valves  100 , 110  to achieve a different predetermined function of the implement (not shown), such as right and left blade tilt. When this occurs, the detent  290  is able to rotate within the slots  380 , 390  to the extent provided while the knife edge  320  is held in a substantially continuous horizontal orientation relative to the ground (not shown). Therefore, the detent assist assembly  210  is held in the second operating position  216  and the blade float function of the implement (not shown) is maintained.  
         [0027]    It should also be understood that the shims  420  are used to control the height of the action plate  400  and, in particular, the height of the knife edge resistance portion  430 . In this manner, the contact of the detent assist assembly  210  with the action plate  400  is controlled to achieve the desired functional effects.  
         [0028]    When the operator (not shown) desires to end the blade float implement function, the control lever assembly  20  must be disengaged from the magnet  590 . To accomplish this, the operator (not shown) may move the joystick portion  30  or disengage the control lever assembly  20  in any other suitable manner, such as electrically or electronically. The joystick portion  30  is then urged to the neutral position  120  via the biasing spring action in the control valves assemblies  75 . The movement of the joystick portion  30  provides enough force to overcome the restriction by the protrusion  480  to automatically move the detent assist assembly  210  to its neutral position  212 .  
         [0029]    When an operator (not shown) desires to operate the joystick portion  30  to achieve various other work machine implement functions in a non-detent mode, the joystick portion  30  may be moved to actuate the control valve plungers  80 , 100 , 110 . It should be understood that the contact portion  260  of the detent housing  230  acts in a similar manner as the pins  510 , 600 , 610  to actuate the respective plunger  80  when the joystick portion  30  is moved to the second control position  66 . Further, when moving the joystick portion  30  toward the first control position  64  so that the knife edge  320  engages with the knife edge resistance portion  430 , tactile feedback is received by the operator (not shown) through resistance felt in the joystick portion  30 . At that instant, the operator (not shown) will know that a particular predetermined function of the implement (not shown), such as blade quick drop, will occur within a preset time period. To prevent the blade quick drop implement function from occurring, the operator (not shown) may choose to return the joystick portion  30  to its neutral position  120  or may continue to move the joystick portion  30  to any one of the control positions prior to the preset time period. However, as is obvious, movement of the joystick portion  30  to the first control position  64  will actuate the control valve plunger  90  and engage the magnetic detent arrangement  542  to achieve the detent mode for the blade float implement function.  
         [0030]    Other aspects, objects and advantages of the invention can be obtained from a study of the drawings, the disclosure and the appended claims.