Abstract:
In a vehicle shift lever assembly for a vehicle in which the shift lever is offset to one side of the transmission actuator arm and in which the lockout mechanism is released by depressing the shift lever, a means is provided to minimize undesirable tipping or turning of the shift lever. Within the preferred form, a plunger and plunger housing combination is provided with sufficient bearing surfaces to minimize tipping and an anti-rotation pin is provided to minimize turning of the shift lever. A detent is also provided to minimize the lockout pin from jumping out of the notch in the lockout plate except when a depressing force is applied to the shift lever.

Description:
BACKGROUND OF THE INVENTION 
     Many trucks and off-road vehicles have drive trains that provide driving torque to all four wheels of the vehicle. This is generally accomplished by a transfer case used to selectively shift the drive train to one of four modes which are: two-wheel, high; four-wheel, high; neutral; and four-wheel, low. In present day transfer cases, the shifting of the drive train into one of these four modes is accomplished by the actuation of a single actuator extending outwardly from the transfer case housing and to which is attached one end of a selector rod, the other end being connected to an arm actuator which is a part of a vehicle shift lever assembly. The vehicle shift lever assembly includes a shift lever which extends upwardly into the driver&#39;s compartment, much like the conventional floor shift lever which extends from the vehicle&#39;s primary transmission. 
     Frequently the transfer case is not aligned directly under the place in the vehicle where the shift lever is to be located. Thus, the shift lever is off-set so as to be spaced laterally and upwardly from the transfer case. Further, the present vehicle shift lever assembly utilized in the shifting of the drive train of a transfer case includes a lockout/mounting plate secured to the transfer case and having a slot with a plurality of notches. A lockout pin extends into the slot and the position of the shift lever and actuator arm is set by locating the pin in a selected one of the notches. In order to move the pin from one notch to the next it is necessary that the pin be depressed downwardly out of one notch and moved in the slot to another notch. In one present day lever assembly this is accomplished by a mechanism whereby the shift lever is pivoted about a horizontal axis extending in a direction along the fore and aft axis of the transfer case which requires pivoting the shift lever in two different directions. 
     Because of the difficulty in the shifting of the drive train in the transfer case by pivoting the shift lever in two different directions, it has been proposed to shift the drive train of a transfer case by depressing the shift lever to move the lockout pin out of the notches of the mounting/lockout plate. However, this creates a substantial problem because of the aforementioned location of the shift lever being spaced laterally from the transfer case and thus the lockout/mounting plate mounted thereon. 
     SUMMARY OF THE INVENTION 
     The present vehicle shifter lever assembly provides for actuating the drive train of a transfer case with a shift lever spaced above and to one side of the transfer case and provides for the actuation of the actuator arm connected to the connecting rod of the transfer case by means of depressing the shift lever downwardly and then rotating it forwardly or rearwardly. This is accomplished with a structure that prohibits tipping or rotating or turning of the shift lever about axes other than the axes on which the actuating arm is to be rotated. Accordingly, the proper feel on actuation of the shift lever is provided and any accidental shifting caused by the lockout pin jumping out of a desired notch of the lockout/mounting plate is prohibited. 
     The above desired result is obtained by providing a plunger mounted adjacent the lower end of the shift lever and extending into a plunger housing secured to the actuator arm attached to the lockout/mounting plate. The lockout pin is secured to the plunger and the shift lever. A spring is provided in the plunger housing for biasing the plunger upwardly causing the lockout pin to be biased upwardly into one of the notches of the lockout/mounting plate. Thus depressing the shift lever moves the locking pin out of the notches permitting the shift lever to pivot and the locking pin to move from one notch to another. 
     The plunger and the plunger housing are sufficiently long to provide the necessary stability to the entire assembly thus assisting in preventing the rotation of the lever except about the pivot axis of the actuator arm. In rotating the lever about such axis, the plunger, plunger housing and actuator arm all rotate in unison. In addition to the plunger housing and plunger as above described, an anti-rotation means in the form of a pin for preventing undesirable rotation of the shift lever is provided. 
     The above described structure includes an upper member to which the shift lever, plunger, lockout pin and means for guiding the anti-rotation pin are all secured. Below the upper member is a lower member supporting the actuator arm, the anti-rotation pin and plunger housing. These two members and the respective elements supported thereby are pivotable together about the pivot axis of the actuator arm. The upper member however is movable downwardly when the shift lever is depressed and is otherwise biased upwardly into locked position for holding the actuator arm in selective positions to control the drive train of the transfer case. 
     In one embodiment of this invention, I also provide a detent means for assisting in the holding of the lockout pin in selected ones of the notches in the lockout/mounting plate. 
     It will be obvious from the above description and the following specific descriptions that the vehicle shift lever assembly of this invention is a rugged but smooth operating assembly that accomplishes the desired result of selectively setting the drive train of a transfer case by depressing and rotating a shift lever that is offset and spaced above and laterally to the side of the transfer case. 
     The function and advantages of the present invention will become apparent after considering the following detailed specification which discloses preferred embodiments thereof in conjunction with the accompanying drawings wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front, elevational view of the shift lever assembly of this invention; 
     FIG. 2 is a cross-sectional view taken along the plane II--II of FIG. 6; 
     FIG. 3 is a side, elevational view of the assembly in the two-wheel drive, high speed position; 
     FIG. 4 is a side, elevational view of the assembly in the neutral position; 
     FIG. 5 is a side, elevational view of the assembly in the four-wheel drive, low speed mode; 
     FIG. 6 is a plan view of the assembly; 
     FIG. 7 is one side, elevational view of the lockout/mounting plate showing the lockout pin in the various modes; and 
     FIG. 8 the opposite side, elevational view of the lockout/mounting plate disclosing an embodiment in which a detent plate is provided for holding the lockout pin in either of the four modes or positions. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings and more particularly by reference numeral, in all of FIGS. 1-6, reference numeral 1 designates a lockout/mounting plate, reference numeral 10 designates an upper plate subassembly and reference numeral 20 designates a lower cast subassembly. The upper plate subassembly 10 and the lower cast subassembly 20 are rotatable on lockout/mounting plate 1 about the pivot pin 2. 
     Lockout/mounting plate 1 is adapted to be secured to a lower case by means of conventional fasteners (not shown) extending through the openings 3a, 3b, and 3c (FIGS. 3, 4, 5 and 7). As shown in FIGS. 3, 4, 5 and 7, the mounting plate 1 includes a slot 5 having the detent notches 6, 7 and 9 extending therefrom. The slot 5 and notches 6, 7 and 9 are adapted for receiving a lockout pin as will be described hereinafter. The lockout/mounting plate 1 also includes an opening 8 receiving the pivot bolt 2 which rotatably supports the subassemblies 10 and 20 in a position for actuating the drive train of a transfer case. 
     The upper plate subassembly 10 is a stamped plate 11 having a configuration as is best disclosed in FIG. 1. Plate 11, stamped in the configuration as shown in FIG. 1, includes a flange 12 at one end to which is attached the lockout pin 13. At the other end of the plate 11 spaced from the flange 12, the plate is configured to provide a clamp 14 for supporting the shift lever or handle 40. Intermediate the two ends 12 and 13 is a plunger 15 secured in the opening 16 of the plate 11 and extending downwardly as best illustrated by FIG. 2. An opening 17 is provided intermediate the plunger and the flange 12 to receive an anti-rotation pin as will be described. A cap 18 is secured in the opening 17 for the purpose of receiving and covering the anti-rotation pin. The cap 18 is held in the opening 17 by the clip 19. 
     The lower cast subassembly includes the actuator arm 21 extending downwardly from a hub 22. An anti-rotation pin 23 cast integrally with the hub 22 extends upwardly into the cap 18 and is slidable within cap 18. A plunger housing 24 is also integrally cast with the hub 22 and actuator arm 21 so that the plunger housing 24, the anti-rotation pin 23, the hub 22 and the actuator arm 21 are all one casting secured to the lockout/mounting plate 1 by means of the pivot bolt 2 extending through the opening 25 of the hub 22. The pivot bolt is secured in place by a push nut 26, it being understood that after assembly of push nut 26, the pivot bolt must turn freely by hand so that the casting can be pivoted freely about the axis of pivot bolt 2. The control link pin 27 is secured to the end of the actuator arm 21 for receiving a rod (not shown) that connects actuator arm 21 to an arm (not shown) located outside of the transfer case for selectively shifting the drive train of the transfer case. 
     Having described the two subassemblies 10 and 20, the interfitting of these two subassemblies should be evident from the drawings. As disclosed, the plunger 15 extends into the plunger housing 24 and is easily slidable therein within a nylon bearing 28. A series of ball bearings could be substituted for the nylon bearing 28. Plunger 15 is biased upwardly by means of spring 30 located in the bore 29 of plunger 15. The spring is constantly under compression so that it constantly biases the plunger and consequently the entire upper plate subassembly upwardly. A boot 31 is secured to upper plate 11 and the plunger housing 24 to prevent any foreign materials or debris from entering into the housing and adversely affecting the sliding action of the plunger in the housing. 
     Also as disclosed in FIG. 2, the pin 23 is slidably mounted in the cap 18. Boot 32 is secured to plate 11 and hub 22 to prevent any foreign material or debris from entering into the inside of cap 18 and adversely affecting the sliding action of pin 23 in cap 18. 
     Referring to FIG. 6, it will be noted that the axes of the shift lever 40, the plunger 16 and the anti-rotation pin 23 are located on the corners of a triangle &#34;T&#34; so as to give stability to shift lever 40; that is, the position of the three axes minimizes rotation, tipping and/or turning of shift lever 40 except for the rotation about the axes of the pivot bolt 2. 
     OPERATION 
     Having described my invention, the operation should be evident. It should be understood that both of the subassemblies 10 and 20 rotate together about the axis of the pivot bolt 2. The only relative movement between the two subassemblies 10 and 20 is the up-and-down motion of the upper plate subassembly 10 with respect to the lower subassembly 20. This is accomplished by applying a force to the knob 41 as indicated by the arrow &#34;F&#34;. The force is sufficient to depress the spring which preferably has approximately a 7.5 lb. force. It will be noted that the shaft 42 of the shift lever 40 is bent so that the knob 41 is approximately above the flange 12. The purpose of this is to minimize any tipping of plate 11, flange 12 and pin 13. In other words, the forces are distributed more evenly along the entire plate 11. 
     When the force &#34;F&#34; is applied to the knob 41, the pin 13 is pushed downwardly from one of the notches in which it is located into the slot 5 (FIG. 7) permitting rotation of shift lever 40 and the entire subassemblies 10 and 20 Consequently, actuator arm 21 is rotated to shift the drive chain of the transfer case. In such shifting action, pin 13 is moved from one of the notches 6, 7 and 9 which determines the mode of the drive train of the transfer case, i.e., whether it is two-wheel, high speed (2H); four-wheel, high speed (4H); neutral (N) or four-wheel, low speed (4L) (FIG. 7). Once the selected mode is reached by rotating the entire assembly (i.e., subassembly 10 and the subassembly 20, while the shift lever is depressed) the force &#34;F&#34; exerted on the handle is released causing upper assembly 10 to be biased upwardly by spring 29 causing lockout pin 13 to move into one of the selected notches as disclosed in FIG. 7. 
     With this mechanism as above described, the desired stability and feel to satisfy the human factor considerations is obtained despite the fact that the shift lever is located at a position spaced to the side of the transfer case. The requirement to rotate the shift lever in two directions in order to shift from one mode to the other is eliminated. Further, the rotation or tipping of shift lever 40 about any other axis than the axis of the pivot bolt 2 is substantially minimized. 
     MODIFICATION 
     FIG. 8 discloses an embodiment of my invention in which the two subassemblies 10 and 20 are identical to that above described. In the embodiment of FIG. 8, a detent plate 50 is added. Detent plate 50 is pivoted on the lockout/mounting plate 1 in the position as shown by the pin 51 and is biased in a counterclockwise direction as viewed in FIG. 8 by a leaf spring 52. The leaf spring 52 is of sufficient strength to hold the detent 50 against the lockout pin 13 but is capable of being overcome by the normal force &#34;F&#34; (FIG. 1) exerted on the knot 41 of shift lever 40 when shifted from one mode to another. The plate is guided on the end opposite the pin 51 by a second pin 53 riding in the slot 57. Detent plate 50 has a plurality of notches 57, 59, 54, and 57 for holding the pin in place in the 4L, N, 4H, and 2H modes, respectively. As disclosed, the ramps are provided adjacent each notch to facilitate the lockout pin 13 in moving the detent plate 50 out of its holding position as the shift lever 40 is depressed and rotated from one mode to another. 
     Having disclosed the preferred embodiment of my invention, it should be understood that many changes, modifications, variations, other uses and applications of the shift lever assembly will become apparent to those skilled in the art after considering this specification and the accompanying drawings. All such changes, modifications, alterations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the following claims.