Abstract:
The detent and neutral switch mechanism includes a roller detent pin attached to a roller spring. The detent pin engages contoured shift fork extensions and resists movement of the shift fork extensions when gears are shifted and creates a “shift feel.” A neutral switch positioned above the roller spring indicates when the transmission is in neutral. When the transmission is in neutral, the deep neutral detent notches on the shift fork extensions are aligned, lowering the detent pin and disengaging the roller spring from the position switch, indicating the transmission is in neutral and that it is safe to make a shift. When the transmission is in gear or in the process of making a shift, the detent pin engages raised in-gear notches or detent peaks, respectively, engaging the roller spring with the position switch indicating that the transmission is not in neutral.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a combined detent and neutral switch mechanism for use in a manually controlled transmission. 
     As the vehicle operator moves a shift lever though the shift pattern, the shift lever moves an operatively connected shift fork extension. The moving shift fork extension in turn selectively engages a shift fork which moves clutch collars into engagement with a gear, causing a gear shift. 
     Prior art manual transmissions assemblies utilize both detent mechanisms and neutral switches, which are separate components within the manual transmission. A detent mechanism provides feedback, or a shift feel, to indicate to the vehicle operator where he is in the shift pattern. As a shift fork extension is moved during a shift, a detent pin coacts with a contoured surface in the shift fork extension and provides resistance to the movement of the shift fork extensions. 
     When shifting gears in a manual transmission assembly, only one shift fork extension can move at a time. It is therefore desirable that the shift fork extensions, and the transmission, be in the neutral position when a shift occurs. A neutral switch is used to provide feedback that the transmission is in neutral. The separate detent and neutral switch mechanisms require additional parts to assemble the manual transmission. Therefore, undue time is needed to assemble and repair the transmission. 
     Hence, there is a need in the art for a combined detent and neutral switch mechanism for use in a manually controlled transmission. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a combined detent and neutral switch mechanism for use with a manually controlled transmission. 
     A manual transmission includes a plurality of shift fork extensions. Each shift fork extension has a neutral detent notch and at least one in-gear detent notch, with detent peaks positioned therebetween. When the transmission is in the neutral position, all the neutral detent notches are aligned. 
     The combined detent and neutral switch mechanism includes a roller detent pin attached to a roller spring. When the transmission is put into gear, the selected shift fork extension translates and the detent pin engages the in-gear detent notch corresponding to the selected gear to resiliently maintain the shift fork extension into the desired in-gear position. 
     The neutral detent notches, in-gear detent notches, and detent peaks are all formed to different depths. The neutral detent notches are formed to the deepest depth, the detent peaks are formed to the shallowest depth, and the in-gear detent notches are formed to an intermediate depth. As the detent pin travels over the contoured surfaces of the shift fork extension, the detent pin biases the roller spring upwardly and downwardly to resist the movement of the shift fork extension and create a “shift feel.” 
     The combined detent and neutral switch mechanism also includes a neutral position switch to indicate when the manual transmission is in neutral. As the selected shift fork extension is translated, the detent pin attached to the roller spring moves in an upwardly and downwardly direction. 
     When the detent pin is located in an in-gear detent notch or on a detent peak, more upward force is applied to the roller spring and the roller spring contacts the position switch. This indicates either that the transmission is in a gear or that a shift is in progress. If all of the neutral detent notches are aligned (the transmission is in neutral) the detent pin lowers into the aligned neutral detent notches, and the roller spring disengages from the position switch, indicating that the transmission is in neutral and that it is safe to make a gear shift, or the switch could be reversed such that it is only engaged when the transmission is in neutral. 
     Accordingly, the present invention provides a combined detent and neutral switch mechanism for use in a manually controlled transmission 
     These and other features of the present invention will be best understood from the following specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features and advantages of the invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
     FIG. 1 illustrates a sectional side view of a manually operated transmission utilizing the combined detent and switch mechanism of the present invention. 
     FIG. 2 illustrates a schematic illustration of the shift pattern of the present invention. 
     FIG. 3 illustrates a front cross sectional view of a manually operated transmission with the shift lever positioned to translate the inner shift fork extension. 
     FIG. 4 illustrates a front cross sectional view of a manually operated transmission with the shift lever positioned to translate an outer shift fork extension. 
     FIG. 5 illustrates a perspective view of the shift fork extensions showing the neutral detent notches, the in-gear detent notches, and the detent peaks. 
     FIG. 6 illustrates a side view of the combined detent and neutral switch mechanism coacting with the neutral detent notch of a shift fork extension. 
     FIG. 7 illustrates a top view of the combined detent and neutral switch mechanism coacting with the shift fork extension. 
     FIG. 8 illustrates a top view of a manually operated transmission utilizing a combined detent and neutral switch mechanism. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the invention may be susceptible to embodiments in different forms, there is shown in the drawings, and herein will be described in detail, specific embodiments with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated and described herein. 
     As shown in FIG. 1, the manual transmission  10  includes a shift lever  12 , a shift finger  14 , and a plurality of shift fork extensions  16 , only one of which is shown. The shift lever  12  operatively translates an axially moveable shift fork extension  16 , each shift fork extension  16  carrying a perpendicularly attached shift fork  18  which operatively moves gears  27  to cause a gear shift. The shift fork  18  can be attached to the shift fork extension by any means, such as shown at  20 . The shift fork  18  further includes a bore  19  through which a shift rail  21  passes to support the shift fork  18  in the manual transmission  10 . The shift rail  21  is parallel to the shift fork extensions  16  and is also perpendicular to the shift forks  18 . The shift lever  12  extends through an aperture  22  in the top cover  24  of the manual transmission  10 , the top cover  24  supporting the transmission components and defining the shift pattern. As the shift lever  12  moves, it operatively translates a selected shift fork extension  16 , which moves an attached shift fork  18 . The shift fork  18  engages and selectively moves a clutch collar  25  into engagement with one of the gears  27 , causing a gear shift. 
     As the shift lever  12  is pivoted forwardly along the X axis, the shift finger  14  engages the rear wall  30  of a shift finger notch  26  formed in the shift fork extension  16 , translating the shift fork extension  16  rearwardly along axis X. Conversely, as the shift lever  12  is pivoted rearwardly, the shift finger  14  engages the front wall  28  of the shift finger notch  26 , translating the shift fork extension forwardly along axis X. When the shift lever  12  is moved from side to side along axis Y as shown in FIGS. 3 and 4, the shift finger  14  pivots and engages a different shift finger notch  26  of a different shift fork extension  16 . The shift pattern of the shift lever  12  is illustrated in FIG.  2 . 
     The manual transmission  10  shifts, or engages gears, by the axial movement of the selected shift fork extension  16  along the axis X from the neutral position. Each shift fork extension  16  has a shift finger notch  26  which extends the entire width  32  of the shift fork extension  16  (as shown in FIGS. 3 and 4) and has a front wall  28  and a rear wall  30  which are engageable by the shift finger  14  to translate the shift fork extension  16  along the X axis either in the forward or rearward direction. When the shift fork extensions  16  are all aligned in the neutral position, the shift finger notches  26  of the shift fork extension  16  are also aligned. 
     As shown in FIGS. 3 and 4, the shift finger  14  has an engageable portion  34  which has a width  36  slightly less than the width  32  of the shift fork extensions  16 , which allows the shift finger  14  to engage only one shift fork extension  16  at a time. The shift lever  12  is pivoted along the Y axis so that the engageable portion  34  of the shift finger  14  is in the shift finger notch  26  of the selected shift fork extension  16 . Thus, the shift lever  12  is pivotable in both the X direction and Y directions. Once the shift lever  12  is pivoted in the Y direction so that the engageable portion  34  of the shift finger  14  is aligned with the selected shift fork extension  16 , the shift lever  12  can then pivoted in either the forward or reverse direction along the X axis to translate the shift fork extension  16  and to select the desired gear. 
     In this embodiment, the manual transmission utilizes three shift fork extensions  16   a ,  16   b , and  16   c , as shown in FIG.  5 . Although three shift fork extensions  16   a ,  16   b , and  16   c  are illustrated in this embodiment, other numbers of shift fork extensions are possible depending on the number of gears. In this embodiment, the three shift fork extensions  16   a ,  16   b , and  16   c  provide four forward speeds and one reverse speed. Shift fork extension  16   a  is the inner shift fork extension  16  which operates the first speed and the second speed. Shift fork extension  16   b  is the outer left shift fork extension which operates the third speed and the fourth speed. Shift fork extension  16   c  is the outer right shift fork extensions which operates the reverse speed. Each shift fork extension  16  carries a shift fork  18  which operatively engages and shift gears  27  to cause a gear shift. 
     Returning to FIG. 1, each shift fork extension  16  has a central neutral detent notch  38  and at least one in-gear detent notch  40  carved into the upper surface  42  of each shift fork extension  16 . Detent peaks  44  are positioned therebetween. The in-gear detent notches  40  are spaced proximate to the neutral detent notches  38 . The neutral detent notches  38  and the in-gear detent notches  40  both extend the entire width  32  of the shift fork extension  16 . When the shift fork extensions  16  are in the neutral position, all of the neutral detent notches  38  are aligned. The in-gear detent notches  40  are spaced apart from the neutral detent notches  38  so that when a selected shift fork extension  16  is positioned in gear, the corresponding in-gear detent notch  40  aligns with the neutral detent notches  38  of the other shift fork extensions  16 . FIG. 5 illustrates the shift finger extensions  16   a ,  16   b ,  16   c , the neutral detent notches  38   a ,  38   b ,  38   c , the in-gear detent notches  40   a ,  40   b ,  40   c ,  40   d ,  40   e , and the detent peaks  44   a ,  44   b ,  44   c ,  44   d ,  44   e  of the present invention. 
     FIG. 6 illustrates the combined detent and neutral switch mechanism  46  of the present invention coacting with a shift finger extension  16 . The detent and neutral switch mechanism  46  includes a cylindrical roller detent pin  48  which engages the detent peaks  44 , neutral detent notches  38 , and in-gear detent notches  40  of the shift fork extensions  16 . The length of the detent pin  48  is greater than or equal to the combined widths  32  of the shift fork extensions  16 . The combined detent and neutral switch mechanism  46  also includes a roller spring  52  which allows upward and downward movement of the detent pin  48  along the Z axis. 
     The detent pin  48  engages the neutral detent notches  38  of the shift fork extensions  16 , when the transmission  10  is in neutral. When the transmission  10  is put into gear, the desired shift fork extension  16  translates along the X axis to an in-gear position, and the detent pin  48  will engage the in-gear detent notch  40  corresponding to the selected gear. The detent pin  48  engages the in-gear detent notch  40  to resiliently maintain the shift fork extension  16  into the desired in-gear position. 
     Each neutral detent notch  38  is formed to a depth A. The in-gear detent notches  40  are all formed to a depth shallower than the depth of the neutral detent notches  38 , represented by a depth B. The detent peaks  44  are all formed to the shallowest depth, represented by a depth C. As shown in FIG. 5, the middle shift fork extension  16   a  has a neutral detent notch  38   a  positioned between a first in-gear detent notch  40   a  and a second in-gear detent notch  40   b . The left shift fork extension  16   b  has a neutral detent notch  38   b  positioned between a third in-gear detent notch  40   c  and a fourth in-gear detent notch  40   d . The right shift fork extension  16   c  has a neutral detent notch  38   c  and a reverse in-gear detent notch  40   e.    
     When the manual transmission  10  is in neutral, the detent pin  48  engages the neutral detent notches  38   a ,  38   b ,  38   c  of all three shift fork extensions  16   a ,  16   b ,  16   c . When it is desired to place the manual transmission  10  in the first gear, the shift lever  12  is positioned so that the engageable portion  34  of the shift finger  14  engages the shift finger notch  26   a  of the middle shift fork extension  16   a . As the shift lever  12  is moved in the forward direction to engage the first gear, the shift fork extension  16   a  moves in the rearward direction, aligning the first in-gear detent notch  40   a  of the shift fork extension  16   a  with the neutral detent notches  38   b ,  38   c  of the other shift fork extensions  16   b ,  16   c . In this position, the detent pin  48  of the combined detent mechanism  46  engages the first in-gear detent notch  40   a  of the middle shift fork extension  16   a  and aligns over the neutral detent notches  38   b ,  38   c  of the other shift fork extensions  16   b ,  16   c.    
     When it is desired to place the manual transmission  10  in the second gear, the shift lever  12  is moved in the rearward direction to engage the second gear. The shift fork extension moves in the forward direction, aligning the second in-gear detent notch  40   b  of the shift fork extension  16   a  with the neutral detent notches  38   b ,  38   c  of the other shift fork extensions  16   b ,  16   c . In this position, the detent pin  48  of the combined detent mechanism  46  engages the second in-gear detent notch  40   b  of the middle shift fork extension  16   a  and aligns over the neutral detent notches  38   b ,  38   c  of the other shift fork extensions  16   b ,  16   c . When shifting to third gear, fourth gear, or reverse, the same process is repeated for the selected shift fork extension  16 . 
     When a shift is in progress, the detent pin  48  contacts detent peaks  44 . A first detent peak  44   a  is located between the neutral detent notch  38   a  of the middle shift fork extension  16   a  and the first in-gear detent notch  40   a , and a second detent peak  44 b is located between the neutral detent notch  38   a  and the second in-gear detent notch  40   b . Detent peaks  44   c ,  44   d  are located on the left shift fork extension  16   b  between the neutral detent notch  38   b , and the third in-gear detent notch  40   c  and the fourth in-gear detent notch  40   d , respectively. Detent peak  44   e  is located on the right shift fork extension  16   c  near the neutral detent notch  38   c . The length  54  of the detent peaks  44  are equal to the amount of movement needed to shift gears. 
     The force of the detent pin  48  on the upper surface  42  of the shift fork extensions  16  provides a shift feel to the operator. The detent pin  48  is attached by pins  72  to an elongated roller spring  52 , the roller spring  52  being fixedly attached to the top cover  24  by fasteners  56 . The detent pin  48  translates up and down along the Z axis as the selected shift fork extension  16  is moved and engages the neutral detent notches  38 , the in-gear detent notches  40 , and the detent peaks  44 , all at different depths, A, B, and C, respectively. As the detent pin  48  travels up one of the side  58  of a neutral detent notch  38  or an in-gear detent notch  40  during a shift, the shift effort increases because the detent pin  48  exerts an upward force on the roller spring in the upwardly Z direction. Once the detent peak  44  is crested and the detent pin  48  engages either the neutral detent notch  38  or another in-gear detent notch  40 , the shift effort decreases as the detent pin  48  travels down the side  58  of the notch and the less force is applied to the roller spring  52 . 
     The combined detent and neutral switch mechanism  46  also includes a neutral position switch  64  to indicate to a control or to the vehicle operator that the manual transmission  10  is in neutral. The reasons for suing neutral state feedback is known in the art. The neutral position is the position where all of the neutral detent notches  38   a ,  38   b ,  38   c  of the shift fork extensions  16   a ,  16   b ,  16   c  are aligned, as shown in FIGS. 7 and 8. 
     The neutral detent notches  38  are the deepest, formed such that the bottom  60  of the neutral detent notches  38  are at a depth A along the Z axis. The in-gear detent notches  40  are shallower than the neutral detent notches and are formed such that the bottom  62  of the in-gear detent notches  40  are at a depth B along the Z axis. The detent peaks  44  are the shallowest and are at a depth C along the Z axis. 
     As the selected shift fork extension  16  is translated along the X axis, the detent pin  48  attached to the roller spring  52  moves in upwardly and downwardly along the Z axis. When the detent pin  48  in positioned in the neutral detent notches  38 , the detent pin  48  contacts the bottom  60  of the neutral detent notches  38  at a depth A along the Z axis. In this position, relatively little upward force is applied on the roller spring  52 . 
     When the detent pin  48  in positioned on a detent peak  44 , the detent pin  48  contacts the surface of the selected detent peak  44  at a depth C, shallower to depth A. When the detent pin  48  is positioned on a detent peak  44 , the greatest amount of force is applied upwardly to the roller spring  52 . 
     When the detent pin  48  is positioned in an in-gear detent notch  40 , the detent pin  48  contacts the bottom  62  of the selected in-gear detent notch  40  at a depth B, intermediate to depths A and C, along the Z axis. In this position, the amount of force applied to the roller spring  52  is intermediate to the amount of force applied to the roller spring  52  when the detent pin  48  is located in the neutral detent notches  38  or on a detent peak  44 . 
     When the detent pin  48  is located in an in-gear detent notch  40  or on a detent peak  44 , more upward force is applied to the roller spring  52  than the amount of force applied if the detent pin  48  was located in the neutral detent notches  38 . A position switch  64  is attached to the top cover  24  and is of a depth  66  such that the upper surface  68  of the roller spring  52  will contact the lower surface  70  of the position switch  64  when the detent pin  48  engages an in-gear detent notch  40  or a detent peak  44 . 
     When the detent pin  48  is located in an in-gear detent notch  40  at a depth B or on a detent peak  44  at a depth C, an amount of upward force is applied to the roller spring  52  such that the upper surface  68  of the roller spring  52  contacts the lower surface  70  of the position switch  64 . When the roller spring  52  contacts the position switch  64 , either the manual transmission  10  is in a gear or a shift is in progress. Once the transmission  10  is again in neutral, the detent pin  48  is lowered to a depth A in the neutral detent notches  38   a ,  38   b ,  38   c  of all the shift fork extensions  16   a ,  16   b ,  16   c , and the upper surface  68  of the roller spring  52  disengages from the lower surface  20  of the position switch  64 . When the roller spring  52  and the position switch  64  are no longer in contact, the separation of the roller spring  52  and the position switch  64  indicates that the transmission  10  is in neutral. 
     There are several advantages to combining the detent mechanism and the neutral position switch. For one, by combining the detent mechanism and the neutral switch, fewer parts are needed in the transmission, requiring less assembly time. Additionally, because there are fewer parts, repairs will be easier and require less time. 
     Accordingly, the present invention provides a combined detent and neutral switch mechanism for use in a manual transmission assembly 
     The foregoing description is only exemplary of the principles of the invention. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specially described. For that reason the following claims should be studied to determine the true scope and content of this invention.