Abstract:
The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere &amp; Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere &amp; Company or otherwise.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a control lever assembly, and more particularly, to a control lever assembly for use in a vehicle transmission control system. 
     An electronically controlled transmission, such as a powershift transmission or an infinitely variable transmission (IVT), requires an operator control device, such as a shift control lever, for generating control signals which are supplied to an electronic control unit which, in turn, controls the transmission. For example, U.S. Pat. No. 6,247,378, issued 19 Jun. 2001 to Newendorp et al., describes an operator control for an IVT. Such shift control levers are subject to being inadvertently bumped or knocked out of their park or neutral positions. Such shift control levers have typically employed space-consuming complex and circuitous travel paths in order to avoid the lever being inadvertently moved into a position which commands vehicle movement. It is desired to have a simple shift control lever assembly which prevents inadvertently lever movement. 
     SUMMARY 
     Accordingly, an object of this invention is to provide a compact control lever assembly which resists inadvertent lever movement. 
     These and other objects are achieved by the present invention, wherein a control lever assembly for a vehicle transmission includes a housing which supports a guide plate having a slot and a recess formed in a central portion of the slot. A carrier member is pivotally coupled to the housing about a pivot pin. A lever has a shaft which is supported by the carrier and which is rotatable and axially movable relative to the carrier. The lever has a knob which is mounted on an end of the shaft and which is received by the slot. A spring is coupled between the shaft and the carrier and is biased to rotate the knob and to urge the lever towards the pivot pin. When the knob is in the slot and outside of the recess, the slot walls prevent rotation of the knob and maintain the lever in a first rotary orientation. When the knob is moved into the recess, the spring is automatically able to rotate the knob and lever into a second rotary orientation. When the knob is in the second orientation, the recess walls are engagable with the knob to prevent the lever from being pivoted about the pivot pin. The housing includes a detent member which engages detent rollers mounted on the carrier to releasably hold the lever in selected positions in the slot. The knob may be manually moved axially over an abutment formed by a wall of the recess and rotated into a third rotary orientation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a control lever assembly according to the present invention; 
     FIG. 2 is a sectional view showing the lever, the guide plate and a portion of the housing of the assembly of FIG. 1; 
     FIG. 3 is a front perspective view of the lever carrier of FIG. 1; 
     FIG. 4 is a back perspective view of the lever carrier of FIG. 1; 
     FIG. 5 is a perspective view of the control lever of FIG. 1; 
     FIG. 6 is a top perspective view of a guide plate of the assembly of FIG. 1; 
     FIG. 7 is a sectional view in a direction opposite to that of FIG.  2  and showing the lever, the guide plate and a portion of the housing of the assembly of FIG. 1; 
     FIG. 8 is a simplified schematic view of a transmission control system including the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, a control lever assembly  10  includes a housing  12 , a guide plate  14 , a lever carrier  16  and a lever  18 . The housing  12  includes a plate  20  and side walls  22 ,  24  and  26 . Walls  22  and  26  form a pair of flanges  28  and  30  to which is attached the guide plate  14 . Plate  20  supports a pivot pin  32  near wall  24 . Pivot pin  32  rotatably supports lever carrier  16  and a friction disk  34  which is biased into engagement with carrier  16  by a coil spring  36  which is also mounted on pin  32 . Lever  18  includes a knob  17  mounted on the end of a cylindrical shaft  21 . A cover plate (not shown) may be mounted on the edges of walls  22 ,  24  and  26  in order to protect interior components. As seen in FIG. 8, the control lever assembly  10  is intended for use with an electronic transmission control unit  11  and an electronically controlled transmission  13 , such as a commercially available IVT, or some other commercially available electronically controlled transmission. 
     As best seen in FIG. 2, a curved detent plate  40  projects from plate  20  and is spaced apart from and located underneath guide plate  14 . Plate  40  has a center of curvature at the axis of pivot pin  32 . First and second pairs of detent grooves  42 ,  44 ,  46  and  48  are formed in the detent plate. Detent grooves  42  and  46  are formed in an upper surface of detent plate  40 , while detent grooves  44  and  48  are formed in a lower surface of detent plate  40 , each lower detent groove being adjacent to and opposite from a corresponding upper detent groove. 
     Referring now to FIGS. 1,  3  and  4 , the carrier  16  has a hub  60  which is rotatably mounted on pin  32  and which engages friction disk  34 . Coil spring  36  is mounted on pin  32  and is biased to urge disk  34  into engagement with an axial end of the hub  60 . A carrier plate  62  extends radially from hub  60 . A support member  64  projects from plate  62  and is spaced apart and radially outwardly from hub  60 . A pair of alignment tabs  61  and  63  project from an end of plate  62  opposite hub  60 . Support member  64  supports a guide pin  66  which extends away from pivot pin  32  and which is slidably received in a bore  91  in the radially inner end of lever shaft  19 . A pair of tabs  70  and  72  project from plate  62 , are spaced apart on either side of lever shaft  19  and positioned radially outwardly from member  64 . An opening  68  is formed in plate  62  radially inwardly of tabs  70 ,  72 . Tabs  70 ,  72  rotatably and slidably engage and support lever shaft  21 . A spring anchor tab  73  projects from an edge of plate  62 . 
     Referring to FIGS. 4 and 7, a detent assembly  74  is mounted near a radially outer end of the plate  62  and on the side of plate  62  which faces towards housing plate  20 . Detent assembly  74  includes a coil spring  76  with a pair of arms  78  and  80 . Each arm rotatably supports a corresponding detent roller  82  and  84 . Spring  76  is biased to urge rollers  82  and  84  towards each other and into engagement with opposite sides of detent plate  40  (as best seen in FIG.  7 ). Plate  62  also carries a permanent magnet  85  which interacts with Hall effect switches (not shown), which are mounted on the back of housing plate  20 , in order to generate signals representing various discrete positions of lever  18  within guide plate  14 . 
     Referring now to FIGS. 1 and 5, a triangular tab  90  projects from the lever shaft  21 . Tab  90  is engagable with carrier plate  62  to limit rotation of lever  18  with respect to carrier  16 . A blind bore  91  extends into the radially inner end of lever shaft  21  and slidably receives pin  66 . An annular collar  92  projects from shaft  21 , is spaced axially apart from tab  90  and is received by opening  68 . Collar  92  is engagable with tabs  70  and  72  to limit the movement of lever  18  axially away from pivot pin  32 . A curved support arm  94  projects from shaft  21  for holding a magnet  95 . A spring anchor arm  96  also projects from shaft  21 . The knob  17  includes an ergonomically shaped upper part  98  and a lower part  100 . A notch  102  is formed in an end of lower part  100 . A spring  104  is coupled between arm  96  of lever  18  and anchor  73  of carrier  16 . Spring  104  is biased to urge lever  18  radially inwardly towards pivot pin  32  and to rotate lever  18  counter-clockwise, viewing FIG.  1 . 
     Referring now to FIGS. 1,  2  and  6 , the guide plate  14  is generally rectangular and includes a longer longitudinally extending upper lever slot  110  and a shorter lever slot  112 . The ends of slots  110  and  112  are joined by ledges  114  and  116 . The ends of upper slot  110  are shaped to accommodate the ends of the lower part  100  of knob  17 . The ends of lower slot  112  are curved to accommodate the cylindrical shape of lever shaft  21  just below knob  17 . Between the ends of lower slot  112 , slot  112  has side walls  118  and  120  which are co-planar with corresponding side walls  122  and  124  of upper slot  110 . A pair of partially circular recesses  130  and  132  are formed in side walls  122  and  124 , respectively. Recess  130  includes a peripheral wall  134  with an inwardly projecting abutment  136  and a bottom wall  138 . Recess  132  includes a peripheral wall  140  with an inwardly projecting rectangular tab  142 , an abutment  144  and a bottom wall  146 . Preferably, detent grooves  42  and  44  receive the detent rollers  84  and  82  when the knob  17  is located between recesses  130  and  132 . Detent grooves  46  and  48  receive the detent rollers  84  and  82  when the knob  17  is spaced apart from recesses  130  and  132  and in a forward position in slot  110 . 
     Referring again to FIG. 1, control lever assembly  10  also preferably includes a set speed adjust knob  150  coupled to a rotary position transducer  152 . The angular position of lever  18  about the axis of pivot pin  32  is sensed by a transducer  154  which is coupled to carrier  16  by a sensor arm  156  and a sensor link  158 . A set of Hall effect switches  160  are preferably attached to the inner side of the cover plate (not shown) in a position so that they interact with a magnet  162  carried by lever arm  94  when the knob  17  is in the recesses  130  and  132 . As a result, the switches  160  can provide signals which represent the rotary orientation of knob  17  and lever  18 . As shown in FIG. 8, these various switches and sensors, and the set speed knob transducer  152  are operatively connected to the transmission control unit  11 . 
     When the knob  17  is within slot  110  and outside of recesses  130  and  132 , the side walls of slot  110  slidably engage the knob  17  and maintain the knob in a first orientation wherein its longitudinal axis is aligned with the longitudinal axis of slots  110  and  112 . The position of the lever  18  in the slot  110  can be utilized as forward and reverse speed positions. 
     When knob  17  is manually moved into the portion of slot  110  between recesses  130  and  132 , before it is rotated it, can be considered to be in a zero speed position. When released, the spring  104  automatically rotates lever  18  counter-clockwise into a second orientation wherein knob  17  engages abutments  136  and  144 . This second orientation can be utilized as a park position of the lever  18 . 
     When knob  17  is moved into the portion of slot  110  between recesses  130  and  132 , the knob  17  can be manually rotated clockwise against the bias of spring  104  until knob engages a side of tab  142 . In this position the lever can be moved manually radially away from pivot pin  32  so that the bottom surface of knob  17  can be raised up above the top outer surface of tab  142 . The knob  17  can then be further manually rotated clockwise into a third rotary orientation wherein notch  102  is aligned to receive tab  142 , whereupon spring  104  will pull the lever  18  axially towards pivot pin  32  until tab  142  is fully received by notch  102 . This third orientation can be utilized as a neutral position of the lever  18 . 
     While the present invention has been described in conjunction with a specific embodiment, it is understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the appended claims.