Abstract:
The invention is a transmission shifting system for a vehicle, the vehicle having a transmission having a push-pull and rotating member for operating the transmission movable in an H pattern. In detail, the invention includes a first reversible electric motor coupled to the member for moving the member backwards and forwards. A second reversible electric motor is coupled to the member for rotating the member clockwise and counter-clockwise. A transmission shifter control system is provided for sequencing the operation of the first and second motors so to move the member in the H pattern upon receipt of an actuation signal.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to the field of shifting systems for transmissions for automobiles and the like and, in particular, to a shifting system for a transmission having an H pattern actuation system. 
         [0003]    2. Description of Related Art 
         [0004]    Originally, all transmission shifting was accomplished manually with a stick type shifter positioned on the floor. However, this made three abreast seating in the front seat of the automobile difficult. To provide for three abreast seating in the front seat, column-mounted manual shifting systems became popular. This mounting position remained popular even when automatic transmissions were introduced. However, sport cars and most racing cars still used floor-mounted shifters. Chrysler Corporation in the 1950&#39;s time frame introduced a transmission controlled by push-buttons located in the center of the steering wheel hub. However, it proved to have a short life and the column mounted shift lever remained the standard. 
         [0005]    When the sports or sporty cars became popular, the trend reverted back to mounting the shifter on the floor, in reality on top of the transmission. In fact, with the advent of “bucket seats” limiting the front of the passenger compartment to two, center mounting the shifter was a significant cost saver. However, more recent advancements, particularly in Formula One racing cars, have produced automatic shifting manual transmissions. That is a manual type transmission with a clutch that can be automatically shifted by use of electronics and hydraulic or electric actuators. This advancement led to the placement of the shifting mechanism back on to the steering column, where paddles and the like accomplish shifting. Presently, this concept is being introduced into production automobiles. In fact, it is being used in conjunction with automatic transmissions on cars manufactured by Porsche and the Pontiac Division of General Motors. Many other manufactures are expected to follow with such shifting systems. 
         [0006]    An alternate approach has been to design manual transmissions such that a floor mounted shift lever, connected by a push-pull cable to the transmission, is only moved forward for upshifts and backward for downshifts, often without the use of the clutch pedal. Thus up-shifting goes from neutral to gears 1, 2, 3, 4, etc.; downshifting goes from gears 4, 3, 2, 1 to neutral. A separate second gear shift lever is used for reverse, which can only activate when the transmission is in neutral. Typically, all that is required to make a shift between forward gears is a slight lifting of the gas pedal while the shift is made. To go into reverse, the first shift lever must be in neutral. These types of transmissions are commercially available, and used primarily in racing cars and off road vehicles. Mendeola Transaxles Incorporated, Chula Vista, Calif., markets a transaxle of this type. It would also be desirable to provide for the conversion of these types of transmissions to make shifting control available on the steering wheel. PBS Engineering, Garden Grove, Calif. makes and uses a paddle shifter system mounted on the steering wheel. Even though the steering wheel mounted paddles activate electrical switches, the system itself is pneumatically powered and requires an air supply system. Other systems use hydraulics, which also require a separate hydraulic system for transmission shifting. 
         [0007]    In applicants co-pending patent application Ser. No. 11/329,352 Shifting Method And System For A Vehicle Transmission, filed on Jan. 10, 2006 discloses a system for a vehicle having a transmission with a push-pull member for operating the transmission movable from a first starting position to a second up-shifting or to a third downshift position. Such transmissions are called sequential shifting transmissions. It uses a reversible electric motor, having an output shaft, with the motor capable of rotating the shaft in first and second directions. The output shaft of the motor is coupled to the push-pull member of the transmission such that rotation of the shaft in a first direction moves the push-pull member toward the first position and when the shaft rotates in the second direction to the third position. A transmission shifter control is provided for actuating the motor to move the input member from the first position to the second position and back to the first position upon receipt of a first signal, and to move the push-pull member from the first position to the third position and back to the first position upon receipt of a second signal. A paddle system mounted on the steering wheel of the vehicle provides the first and second signals. However, this invention is not applicable to H pattern shifting transmissions. 
         [0008]    Thus, it is a primary object of the invention to provide a transmission shifting system that converts a floor mounted or column mounted shifting system to a steering wheel mounted system. 
         [0009]    It is another primary object of the invention to provide a transmission shifting system that converts a floor mounted or column mounted shifting system to a steering wheel mounted system for after-market installation on automobiles. 
         [0010]    It is a further object of the invention to provide a transmission shifting system that that is electrically powered and easily installed. 
         [0011]    It is a still further object of the invention to provide a transmission shifting system for a transmission that shifts between gears in an H pattern shifting transmission. 
       SUMMARY OF THE INVENTION 
       [0012]    The invention is a transmission shifting system for automobiles. The automobile includes a transmission having a push-pull and rotating member for operating the transmission movable in an H pattern. The system includes a first reversible electric gear motor coupled to the member for moving the member in a back and forth direction. A second reversible electric motor is coupled to the member for rotating both clockwise and counter-clockwise. A control system is provided for the actuation of the first and second electric motors such that the member can be moved in an H pattern. 
         [0013]    Preferably, the motors include an anti-backlash gear system between the motors and their output shafts. A first mechanism is provided for coupling the output shaft of the first motor to the member such that rotation of the shaft in the first direction pushes or pulls the push pull and rotating member in one direction and rotation of the first motor in the opposite direction moves the member in a second direction. A second mechanism is provided for coupling the output shaft of the second motor to the push pull member such that rotation of the second motor in a first direction rotates the push pull and rotating member clockwise and rotation of the second motor in the counter clockwise direction cause the push pull and rotating member to rotate counter clockwise. 
         [0014]    The automobile includes a steering wheel with a gear selection system mounted thereon, which provide a first and second signal to the transmission control system. These first and second signals are interpreted by the transmission control system to either cause an up shift or a downshift of the transmission. 
         [0015]    The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiments of the invention are illustrated by way of examples. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a partial view of the interior of an automobile dashboard, steering column and center console with transmission shifter. 
           [0017]      FIG. 2  is side view of a vehicle equipped with the transmission shown in  FIG. 1 . 
           [0018]      FIG. 3A  is a schematic of a typical H pattern  5  speed shifter. 
           [0019]      FIG. 3B  is a partial view of the transmission illustrating the linear translation of a typical H pattern transmission gear shift operating shaft during shifting. 
           [0020]      FIG. 3C  is a rear view of a typical H pattern transmission illustrating the rotational movement of the transmission gear shift operating shaft during shifting. 
           [0021]      FIG. 4  is perspective view of a steering wheel and column with gear shift actuator switches mounted thereon. 
           [0022]      FIG. 5  is plan view of the automobile shown in  FIG. 2  illustrating the mounting of the subject shifting system. 
           [0023]      FIG. 6  is a cross-sectional view of the housing containing the drive assemblies used to shift the transmission. 
           [0024]      FIG. 7  is a cross-sectional view of  FIG. 6  taken along the line  7 - 7 . 
           [0025]      FIG. 8  is an enlarged view of a portion of  FIG. 5  illustrating the connection of cables from the drive assemblies shown in  FIGS. 6 and 7  to the transmission 
           [0026]      FIG. 9  is partial end view of the transmission shown in  FIG. 8  taken along the arrow  9 . 
           [0027]      FIG. 10  is a functional diagram of the control system for the transmission shifting system. 
           [0028]      FIG. 11  is a typical computer screen that is used for programming the transmission shifting system. 
           [0029]      FIGS. 12A and 12B  are an overview flow chart of the computer program used to control shifting of the transmission. 
           [0030]      FIGS. 13A and 23B  are a flow chart of a computer program for determining if a shift request is valid 
           [0031]      FIG. 14  is a flow chart of the computer program for determining if a neutral gear request if valid. 
           [0032]      FIG. 15  is a flow chart of the computer program for determining if a reverse gear request if valid. 
           [0033]      FIG. 16  is a flow chart of the computer program for determining if the accumulated target gear is valid. 
           [0034]      FIG. 17  is a flow chart of the computer program for executing shift movements. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0035]    Referring to  FIGS. 1 and 2 , the dashboard  10  includes an instrument panel  12 , a transmission gear display  14 . Also illustrated are the gas pedal  15 , brake pedal  16  and clutch pedal  17 . Additionally illustrated are the steering column  18  and steering wheel  19 , and transmission  20  coupled to an engine  21  with an engine management system  22 . 
         [0036]    Referring to  FIGS. 1 and 3A , B, C, the transmission is shifted using a center mounted shift lever  24  that moves in an H Pattern ( FIG. 3A ) and controls the forward gears, neutral, and reverse. Shift lever  24  is connected by a push-pull and rotational rod  26  to the transmission  20 . The rod  26 , has a first end  27 A connected to the lever  24  and a second end  27 B connected to a shifting input shaft  28  on the transmission  20 . Such shifting patterns are called H patterns because the early manual transmissions in automobiles had three forward gears and one reverse gear. First gear was up and to the left, second gear was down to the left, third gear was up and to the right, and reverse was down to the right. Of course, various existed. Present day  4  to  6  forward gears and one reverse are common; however, they are still referred to as H patterns, even though it has more than 3 forward speeds and therefore more than four gear positions. 
         [0000]    The input shaft  28  translates as well as rotates to shift gears. Showing a typical 5 speed transmission, in position  28 A it is in either gears 1 st , 3 rd  or 5 th , depending upon its rotational position. In position  28 B it is in 2 nd , 4 th  or Reverse, also dependent upon rotational position. 
         [0037]    In the subject invention, rod  26  and the lever  24 , are removed in their entirety. 
         [0038]    The subject invention eliminates the need for the driver to take his or her hands off of the steering wheel. Referring to  FIG. 4 , a commercially available steering wheel  19 A mounted on steering column  31  having a “paddle wheel switch” or push button system can be used, which replaces the shift lever  24  and steering wheel  19 . The wheel shifter  19 A is available from American Supercars and Prototypes, LLC. Fallbrook, Calif. The steering wheel includes paddle switches  32 A and  32 B for up shifting and button type switches  34 A and  34 B for downshifting. Of course, some models will have only one paddle switch  32 A for up shifting and one paddle switch  32 B for downshifting. In the model shown in  FIG. 4 , an electrical signal is sent down the steering column  31  to a controller  38 , which controls up shift and downshift requests, the operation of which will be subsequently discussed. Twist Machine, LLC., Hampton, N.Y., also manufactures a paddle type steering wheel which uses an RF signal generator mounted in the steering wheel which can be used to send the signals to the transmission controller  38 . 
         [0039]    Still referring to  FIGS. 1-4  and additionally to  FIGS. 5-9 , a housing  39  is mounted in proximity to the transmission  20 . The housing  39  contains the transmission shifting controller  38  and includes two drive assemblies  47 A, which is used to translate the shaft  28 , and  47 B, which is use to rotate the shaft  28 . 
         [0040]    Drive assembly  47 A includes an electric motor  48  having an anti-back lash gear reduction unit  50  coupled to an output shaft  52  that extends out of a side wall  54  of the housing  39 . A suitable combination electric motor and anti-backlash gear assembly is Part No.: 9390453042, manufactured by Robert Bosch Limitada, Campinas, Brazil. A lever  56  having first and second ends,  58 A and  58 B, respectively, and a middle hole  58 C is mounted to the shaft  52  by its middle hole  58 C. The second end  58 B includes a ball fitting  60 . A cable  62  includes a first end  63 A that includes a quick disconnect fitting  64  adapted to mate with ball fitting  60 . The cable is preferably Part Number 175-403-001XQ, manufactured by Control Cables, Incorporated, Santa Fe Springs, Calif. Thus the ball fitting  60  is in releasable engagement with the quick disconnect fitting  64 . 
         [0041]    A hollow fitting  66  having first and second ends  67 A and  67 B is coupled by its first end to the shaft  28  and attached thereto by fastener assembly  68  extending through a hole  69  in the fitting and shaft. The second end  67 B terminates in a flange  70  having a ball fitting  72  thereon. A pair of parallel flanges  74 A and  74 B are mounted on the body of the fitting  66  between the first and second ends  67 A and  67 B. A bracket  76  having first and second ends  77 A and  77 B is mounded by first end  77 A to the transmission  20  by means of fastener assembly  78  A right angle link  73  having legs  80 A and  80 B is pivotally mounted at its center  81  to the second end of the bracket  76 . The end of leg  80 A terminates in a roller assembly  82  mounted between the two flanges  74 A and  74 B. The end of leg  80 B terminates in a ball fitting  75 . The second end  64 B of the cable  62 , supported by structure  79 , terminates in a quick disconnect fitting  83  that releasably engages the ball fitting  75 . Thus as the cable  62  translates backwards and forwards, the link  73  rotates clockwise or counter clockwise about its center  81 , and the fitting  66  and shaft  28  translates backwards or forwards. 
         [0042]    A position sensor  90  is coupled to the sidewall  54  of the housing  39  having an output shaft  92 . A lever  94  is rigidly coupled by its first end  95 A to the shaft  92 . A link  96  is pivotally coupled by its first end  97 A to the second end  95 B of the lever  94  and by its second end  97 B to the first end  58 A of lever  56 . Thus when lever  56  rotates, the position sensor  90  can measure its angular position, which in turn, measures the position of the shaft  28  on the transmission  20 . 
         [0043]    Drive assembly  47 B also includes an electric motor  100  having an anti-back lash gear reduction unit  101  coupled to an output shaft  102  that extends out of a side wall  54  of the housing  39 . A lever  106  having first and second ends,  108 A and  108 B, respectively, and a middle hole  108 C is mounted to the shaft  102  by its middle hole  108 C. The second end  108 B includes a ball fitting  110 . A cable  112  includes a first end  113 A incorporating a quick disconnect fitting  116  adapted to mate with ball fitting  110 . Thus the ball fitting  110  is in releasable engagement with the quick disconnect fitting  116 . The second end  113 B of the cable  112 , supported by structure  79  terminates in a quick release fitting  118  which is in releasable engagement with the ball fitting  72  on the flange  70 . Therefore, movement of the cable  112  causes the shaft  28  to rotate. 
         [0044]    A position sensor  120  is coupled to the sidewall  54  of the housing  39  and having an output shaft  122 . A lever  124  is rigidly coupled by its first end  125 A to the shaft  122 . A link  127  is pivotally coupled by its first end  128 A to the second end  128 B of the lever  124  and by its second end  128 B to the first end  108 A of lever  106 . Thus when lever  106  rotates, the position sensor  120  can measure its angular position, which in turn, measures the rotational position of the shaft  28  on the transmission  20 . 
         [0045]    Referring to  FIG. 10 , the shifting controller  38  further includes a control circuit, indicated by numeral  140 , which includes a digital control device  142  that receives up shift signals from switches  34 A and  34 B and downshift signals  32 A and  32 B, a signal from a clutch position switch  144  coupled to the clutch pedal  17  (See  FIG. 1 ), and a neutral safety switch  147 , which can be located on dashboard  10  of the automobile. A suitable digital control device  142  is Part No.; MC33993DWB manufactured by Freescale Semiconductor, Austin, Tex. The output from the digital control device  142  is provided to a microprocessor  150 . A suitable microprocessor is Part No.: PIC18F67722-E/PT manufactured by Microchip Technology, Chandler, Ariz. 
         [0046]    Also included is an analog control device  152  that receives input from the electric motor position sensors  90  and  120 . A suitable analog control device is Part No.: MCP6002-E/SN manufactured by Microchip Technology, Chandler, Ariz. There are outputs on the Digital controller and the Analog controller which can be used to send gear display information to a gear indicator  14  which could be located on the dash  10  or on the steering wheel  19 A (see  FIG. 4 ). The output from the analog control device is also coupled to the microprocessor  150 . A speed sensor  155 , which receives signals from the engine management system  22 , can be provided that is coupled to the microprocessor  150  A suitable speed sensor input device is Part No.: CS1124YD8 also manufactured by Microchip Technology, Chandler, Ariz. Also coupled to the microprocessor  150  is a serial communication port  149  to allow programming by means of a personal computer  141 . The microprocessor  150  also controls two motor drivers  160 A and  160 B which are coupled to motors  48  and  100 . The motor drivers supply current to the motors to drive them either clockwise or counter clockwise, so as to cause the motors to move the shift mechanism in the proper sequence to do an up shift or downshift. 
         [0047]    In the above system the following items are optional: 
       1. Gear selector display  14 . 
       [0048]    2. Neutral Safety Switch  147 —When this option is enabled, a shift from forward gears into neutral will not be permitted unless this switch is activated. That is going from 1 st  into neutral would only occur when the neutral safety switch is activated.
 
3. Clutch Switch  144 —When this option is enabled, the driver will not be able to shift out of neutral and into a forward gear without this switch being activated. The clutch switch is typically mounted so that it is activated by depressing the clutch pedal  17 .
 
5. Speed Sensor  114 —When the RPM Safety option is enabled, the shifter unit will not downshift until a certain speed/rpm limit is met. The purpose of this feature is to limit over-revving when downshifting.
 
         [0049]      FIG. 11  illustrates a computer screen presentation  129  that is used to activate the optional devices and initially setup the transmission type. As can be seen, the neutral safety switch  147  is covered by input  130 , and the clutch switch  144  by input  131 . There is a drop down box  132  to select the transmission type, which determines the throws at the transmission and the location of the gears. The reverse safety option is covered by input  133 . Speed sensor  114  is covered by input  135 , with the RPM limit settable by, text box  136 , Max engine RPM settable by  137 , and transmission gear ratios settable by  138 . Thus control is easily accomplished by use of the personal computer  141  using the computer screen  129 . 
         [0050]    Presented in  FIGS. 12-17  are flowcharts of the computer program contained in the microprocessor  150   
         [0000]      FIGS. 12A and 12B  present the main flowchart for the computer and include the following steps:
 
Step  170 —Determine If “To Neutral” Request Pending?—The firmware checks to see if a To Neutral command was given. A to neutral command is used to set the transmission into neutral position. If a to neutral request Is pending then to Step  172 ; if not pending, then to Step  174 .
 
Step  172 —Set Accumulated Target To Neutral and Initiate Or Re-initiate Clutch Timeout. At this point the clutch timeout is reset and the requested gear is set to Neutral. Then to Step  180 .
 
Step  174 —Determine If “Up” Or “Down” Request Pending. A check is made to see if the user issued an up or down shift request. If yes, then to Step  176 ; if no to Step  180 .
 
Step  176 —Determine If Shift Request Valid. The firmware then checks to make sure that the shift request that the user has issued is a valid request. See flowchart in  FIGS. 13A and 13B  for details of process. If no, to step  180 ; if yes, to Step  178 .
 
       Step  178 —Add Shift Request To Accumulated Target and Initiate Or Re-initiate Clutch Timeout—The requested valid shift is now added to the accumulated target gear. 
       [0051]    Step  180 —Determine Whether Accumulated Target Is Current Gear. A check is made to see if the current target gear is the gear that the transmission is now in. If the transmission is now in the requested gear, no further action is needed and the loop continues until another shift request is given; go back to step  170 . If the transmission is not in the requested gear then there is still work to be done to get the transmission into that requested gear; go to step  182 .
 
Step  182 —Clutch Pedal Depressed. A check is made to make sure the clutch pedal is depressed. If the clutch is not depressed then the shifter unit needs to give the driver a chance to press that clutch pedal before attempting the shift, or allow the driver more time to accumulate shifts. Thus if no, to step  184 ; if yes, to Step  188 .
 
Step  184 —Determined If Clutch Timeout Complete.—The firmware checks to see if the driver has waited too long to press in the clutch and therefore it need to reset his request. This timeout value is configurable: some users may want it set at two seconds, some may want it longer. If the time allocated for the driver to press the clutch has expired then to Step  186 ; if no to Step  170 .
 
Step  186 —Set Accumulated Target Gear To Current Gear and return to step  170 . Since the driver has waited too long to press the clutch pedal, we need to reset the gear to the current gear so that if at a later time the driver presses the clutch, that the shifter unit will not attempt to shift the transmission. Think of a situation where the driver is going into a curve. The driver wants to downshift, so he or she presses the downshift paddle. However, if the driver does not depress the clutch, and then decides not to downshift; there could be a problem. For example, two minutes later the driver may wish to slow down a bit so he or she puts in the clutch, and all of a sudden the transmission downshifts. This is definitely something to be avoided. After the accumulated gear is set to the current gear the loop continues at step  170 .
 
       Step  188 —Determine If Accumulated Target Valid—Here the firmware runs some checks prior to moving the shift linkage to make sure all criteria have been meet; which is described in FIG. 16. If no, to step  186 ; if yes, to step  190 . 
       [0052]    Step  190 —Execute shift movement. This step is covered in  FIG. 17 . 
         [0053]    Referring to  FIGS. 13A and 13B , the Step  176  Determine If Shift Request Valid (referred to in  FIGS. 12A and 12B ) checks whether an upshift or downshift request is valid and includes the following steps: 
         [0000]    Step  192 —Determine If Shift Direction Is Up, And Accumulated Target Gear Is Highest Gear. Here a check is made to make sure that the user is not trying to shift past the highest gear that has been set for the shifter based upon the transmissions highest gear. For example, the driver has a 4 speed transmission and currently the accumulated gear is 4 th , and a shift request has been made to go to a fifth, non existent gear. The shift is ruled invalid and a “no” is returned by step  176 . If the accumulated target gear is not the highest gear and the shift direction is up, then the shift so far can be allowed and thus to Step  194 .
 
Step  194 —Determine If Shift Direction Is Down, And Current Gear Is Reverse. The driver can not downshift past reverse, so the shift is invalid, and a “no” is returned by step  176 . If the current gear is not reverse than the down shift is so far valid and thus to Step  196 .
 
Step  196 —Determine Shift Direction Is Down, And The Accumulated Target Gear Is 1 st . If not a downshift from 1 st  into Neutral, go to Step  200 . If it is a downshift from 1 st  into Neutral, a check must be made to verify that a downshift into neutral is allowed; go to Step  198 .
 
Step  198 —Determine If Neutral Request Valid. Here a check is made to make sure that the downshift request into neutral gear is valid and will be allowed. The Process involved in Step  198  is discussed in the  FIG. 14  Flowchart. After the check, if the request is not valid than a “no” is returned by step  176 . If the request is valid, then to Step  200 .
 
Step  200 —Detemine If Shift Direction Is Down And Accumulated Target Gear Is Neutral. If it is not a downshift or the current accumulated gear is not Neutral then step  176  returns a “yes”. If it is a downshift and the current accumulated gear is neutral than a check must be made to verify that a shift into reverse is allowed; go to Step  202 .
 
Step  202 —Determine If Reverse Request Is Valid. Here a series of checks are made to make sure that a shift into Reverse will be allowed and process is presented in  FIG. 15 . If the answer is no, step  176  returns a “no”. If a yes is returned after the check then the shift is valid and a “yes” is returned by step  176 .
 
         [0054]    Referring To  FIG. 14 , the Step  198  Determine If Neutral Request Is Valid (referred to in  FIGS. 13A and 13B ) checks whether a request to shift into neutral gear through a downshift signal is valid and includes the following steps: 
         [0000]    Step  204 —Determine If Neutral Safety Input Enabled. The Neutral Safety input is a user configurable option that checks to make sure a switch is pressed prior to allowing a downshift into neutral. If this option has been disabled by the driver, then there is no need to check the Neutral Safety switch. Thus, the program goes to Step  208 . If this option is enabled than to Step  206 .
 
Step  206 —Determine If Neutral Safety Input Active. This is to see if the Neutral Safety button is being pressed which will, so far, allow the shift into Neutral. If the button is being pressed then to step  208 . If the button is not being pressed then the shift into Neutral is considered not intentional and step  198  returns a “no”.
 
Step  208 —Determine If Neutral Safety Press Time Check Enabled. This is a driver configurable option that will not allow a downshift into neutral without the downshift button being pressed for a certain configurable amount of time. If this option is not enabled, then no further checks need to be made and step  198  returns a “yes”. If this option is enabled, the driver needs to make sure that he or she has held down the button for the configurable amount of time before we allow the shift into Neutral to be valid; go to step  210 .
 
Step  210 —Determine If Press Time Of Current Shift Request Longer Than Press Time Threshold. Here the controller makes sure that the button or paddle is held down for a long enough period such that the criteria that tells the shifter unit that indeed the driver wishes to shift into Neutral has been met. If the time threshold has been met, then the shift into Neutral is valid, and step  198  returns with a “yes”. If the user did not hold down the button or paddle long enough for the shifter unit to verify that the driver indeed wishes to go into Neutral then step  198  returns a “no”.
 
         [0055]    Referring to  FIG. 15 , the step  202  Determine If Reverse Request Is Valid (referred to in  FIGS. 13A and 13B ) checks whether a request to shift into reverse gear is valid and includes the following steps: 
         [0000]    Step  212 —Determine If Reverse Safety input enabled. This is a check to see if the driver has enabled the optional reverse safety input. If the driver has enabled the safety he is required to push an auxiliary button to activate the reverse safety. This auxiliary button may be a dash-mounted button to be pressed manually, or it may be a switch coupled to the brake pedal. In the latter case, the driver would be required to press the brake pedal instead of pushing a dash-mounted pushbutton for a shift into reverse gear. If this option is used to step  214 , if not to step  216 .
 
Step  214 —Determine If Reverse Safety Input Active. Since the Driver has enabled the reverse safety input then the program must check to make sure the switch (be it user activated or based of the brake being pressed) is in the active position. If the reverse safety switch is not active then the shift into reverse is not valid and a “no” is returned by step  202 ; if it has been activated then to step  216 .
 
Step  216 —Determine If Reverse Safety Press Time Check Enabled. This is a driver configurable option that will not allow a shift into reverse without the downshift button being pressed for a certain configurable amount of time. If this option is not enabled, step  202  returns a “yes”. If this option is enabled then it must be determined that the button has been held down for the configurable amount of time before a shift into reverse becomes valid. Thus to step  218 .
 
Step  218 —Determine If Press Time of Current Shift Request Was Longer Than Press Time Threshold. Here it is determined if the driver has held down the button or paddle for a long enough period that the criteria that tells the shifter unit that indeed the driver wishes to shift into reverse has been met. If the time threshold has been met, then the shift into reverse is valid, and a “yes” is returned by step  202 . If the driver did not hold down the button or paddle long enough for the shifter unit to verify that the driver indeed wishes to go into Neutral then a “no” is returned by step  202 .
 
         [0056]    Referring to  FIG. 16 , the step  188  Determination Accumulated Target Valid (referred to in  FIGS. 12A and 12B ) checks immediately before the execution of a shift movement whether the target gear is valid and includes the following steps: 
         [0000]    Step  220 —Determine If Speed Is Within Permitted Range For Accumulated Target Gear. This is a check to verify that the speed of the vehicle is within range for the shift to be safely made. A downshift from 5 th  to 1 st  at 120 mph would usually destroy the engine or the transmission. This can be prevented using these configurable speed rules. These values will be adjustable and are in no way permanently set to a specific speed or threshold. If the vehicle is going too fast for the shift to safely be made then a “no” is returned by step  188 . If the speed is within the configurable speed limits then one final check is made to verify that the shift is valid; go to step  222 .
 
Step  222 —Determine If Accumulated Target Is Reverse And Speed Safety Is Enabled. This is a further safety measure to verify that the vehicle is not currently rolling faster than is safe to engage the Reverse gear. This option can be disabled. If this option is disabled then no further checks need to be made and a “yes” is returned by step  188 . If this safety is enabled then we must verify that the speed is within the limits to permit the shift into Reverse; go to step  224 .
 
Step  224  Determine If Speed Is Below Reverse Threshold. Here the program checks to make sure that the vehicle is not moving faster than is safe to engage reverse gear into. If the speed is below the configurable threshold then a “yes” is returned by step  188 . If the speed is over the threshold then a “no” is returned by step  188 .
 
         [0057]    Referring to  FIG. 17 , the Step  190  Execute Shift Movement (referred to in  FIGS. 12A and 12B ) includes the following steps: 
         [0000]    Step  226  Determine Target Positions Of Motors  1  and  2 —Once the program knows the final accumulated gear, the program instructs the two motors how they must relocate to get the transmission in the correct gear. The movement that these two motors make will vary between different transmission models. The transmission model will be selected using the software supplied with the unit ( 132  of  FIG. 11 ). When the transmission model is selected, the gear values will be saved to the shifter unit. These gear values will be used by the firmware to place the two motors in the correct locations. Motor  1  does the in/neutral/out motions, while motor  2  does the multiple lines of rotation. A 3 speed transmission will have 2 or 3 lines of rotation, a 4 to 5 speed will have 3 or 4 lines of rotation, and 6 speeds will have 4 or 5 lines of rotation. 
       Step  228 —Move Motor  1 —Motor  1  is moved into the neutral position. 
       [0058]    Step  230 —Move Motor  2 —Motor  2  is then moved to the correct line. It is possible that Motor  2  may not move during a shift, such would be the case when it is a shift from 1 st  to 2 nd  which would be on the same line of movement. 
       Step  232 —Move Motor  1 —Motor  1  is then moved a second time to place the transmission into the correct gear. 
       [0059]    Thus it can be seen that by using electric motors with anti-backlash gears, steering wheel mounted shifting switches, the transmission shifting program in the microprocessor, and the various sensors and switches, shifting can be accomplished without the driver removing his or her hands from the steering wheel. Additionally, the safety interlocks insure that inadvertent shifting into the wrong gear position or over-revving of the engine can be prevented. Furthermore, it must be noted that, while an automobile transmission is used as an example, other vehicles, such as boats, can make use of this invention. 
         [0060]    While the invention has been described with reference to particular embodiments, it should be understood that the embodiments are merely illustrative, as there are numerous variations and modifications, which may be made by those skilled in the art. Thus, the invention is to be construed as being limited only by the spirit and scope of the appended claims. 
       INDUSTRIAL APPLICABILITY 
       [0061]    The invention has applicability primarily to the automobile and boat industries.