Abstract:
A transfer case assembly ( 10 ) for selectively moving a seat assembly in a plurality of adjustment directions. The assembly comprises a motor ( 12 ) and a drive shaft ( 14 ) operatively connected to the motor ( 12 ) for rotation in response to actuation of the motor. A plurality of driving gears ( 16, 18, 20 ) are mounted to the drive shaft for rotation therewith. A plurality of driven ( 24, 28, 32 ) shafts corresponding with the respective plurality of driving gears are provided for independently controlling movement of the seat assembly in the fore/aft, up and down direction. A driven gear is rotatably mounted to each of the driven shafts and meshed with a respective one of the driving gears for rotation therewith. A coupler ( 22, 26, 30 ) is disposed adjacent to each of the driven gears for selectively coupling the driven gears to the respective driven shafts ( 24, 28, 32 ). A solenoid ( 38, 52, 66 ) is disposed adjacent to each of the couplers ( 22, 26, 30 ) for operative engagement therewith for selectively coupling the driven gears with the respective driven shafts to transfer rotation of the drive shaft to rotation of the driven shafts through independent or simultaneous actuation of the solenoids and the motor whereby the seat assembly may be moved in one or more of the plurality of adjustment directions.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The subject invention relates to a multi-output transfer case for a power automotive seat which utilizes a single motor. 
   2. Description of the Related Art 
   Manual and power adjustment mechanisms for automobile seats are common in the automotive industry. The adjustment mechanisms typically allow an operator to raise or lower a front or rear portion of the seat, or move the seat forward and rearward. The adjustment mechanisms usually include separate actuators for raising the front portion of the seat independently of the rear portion. Also, a separate actuator is typically used to move the seat forward and rearward and to move the entire seat up and down. In other words, a separate actuator is typically needed for each axis of movement. 
   Powered seats typically require at least two motors to raise the front and rear portions independently of each other. A third motor is required to move the seat forward and rearward. These multiple motors increases the complexity and cost of the adjustment mechanism. 
   SUMMARY OF THE INVENTION 
   The disadvantages of the prior art may be overcome by providing a multi-output transfer case having a single motor for providing movement of a seat assembly along multiple axes. 
   According to one aspect of the invention, a transfer case assembly is provided for selectively moving a seat assembly in a plurality of adjustment directions. The assembly comprises a motor and a drive shaft operatively connected to the motor for rotation in response to actuation of the motor. A plurality of driving gears are mounted to the drive shaft for rotation therewith. A plurality of driven shafts corresponding with the respective plurality of driving gears are provided for independently controlling movement of the seat assembly. A driven gear is rotatably mounted to each of the driven shafts and meshed with a respective one of the driving gears for rotation therewith. A coupler is disposed adjacent to each of the driven gears for selectively coupling the driven gears to the respective driven shafts. A power actuator is disposed adjacent to each of the couplers for operative engagement therewith for selectively coupling the driven gears with the respective driven shafts and transfer rotation of the drive shaft to rotation of the driven shafts through independent or simultaneous actuation of the actuators and the motor whereby the seat assembly may be moved in one or more of the plurality of adjustment directions. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
       FIG. 1  is a perspective view of a transfer case assembly in accordance with the subject invention; 
       FIG. 2  is a top view of the transfer case assembly, 
       FIG. 3  is a front view of the transfer case assembly; 
       FIG. 4  is a side view of the transfer case assembly; 
       FIG. 5  is a perspective view of a seat track assembly having upper and lower tracks in which the transfer case assembly is mounted thereto; and 
       FIG. 6  is a perspective view of the lower track of the seat track assembly. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the Figures, wherein like numerals indicate alike or corresponding parts throughout the several views, a multi-output transfer case assembly is generally shown at  10  in  FIG. 1 . The transfer case assembly  10  is designed to move a seat cushion (or seat assembly) up, down, forward and rearward. In particular, the transfer case assembly  10  can independently move a front portion of the seat cushion up and down, independently move a rear portion of the seat cushion up and down, or move the entire seat cushion up, down, forward or rearward. The seat cushion is part of an entire automotive seat assembly which also includes a seat back as is known in the art. The transfer case assembly  10  is uniquely designed to incorporate a single motor  12  for providing, or powering, the up, down, forward and rearward movements for the seat cushion. 
   A drive shaft  14  is rotatably coupled to the motor  12  such that the motor  12  drives the drive shaft  14 . The motor  12  is of any conventional design and couples to the drive shaft  14  in any conventional manner. First  16 , second  18  and third  20  driving gears are fixedly mounted to the drive shaft  14  in spaced relationship to each other and rotate with the drive shaft  14 . As will be discussed in greater detail below, the first driving gear  16  selectively engages a first coupling  22  to couple the first driving gear  16  to a fore-aft shaft  24  for moving the seat cushion forward and rearward. The second driving gear  18  selectively engages a second coupling  26  to couple the second driving gear  18  to a front vertical lift shaft  28  for moving the front portion of the seat cushion upward and downward. Finally, the third driving gear  20  selectively engages a third coupling  30  to couple the third driving gear  20  to a rear vertical lift shaft  32  for moving the rear portion of the seat cushion upward and downward. 
   Referring also to  FIGS. 2 through 4 , the first  22 , second  26  and third  30  couplings are discussed in greater detail. Each of the couplings  22 ,  26 ,  30  includes at least a free spinning driven gear, a toothed clutch and a solenoid. 
   In particular, the first coupling  22  includes a first driven gear  34  which rotates freely about the fore-aft shaft  24 . The first driven gear  34  is in constant driving engagement with the first driving gear  16 . It should be appreciated that both the first driven gear  34  and the first driving gear  16  have co-acting teeth for transferring rotary motion of the first driving gear  16  to rotary motion of the first driven gear  34 . As best shown in  FIGS. 2 and 3 , a plurality of tabs  35  extend from the first driven gear  34  to selectively engage a first engagement ring  36 . The first engagement ring  36  is non-rotatably and slidably mounted to the fore-aft shaft  24  and includes corresponding tabs  37 . As will be appreciated, the first engagement ring  36  slides longitudinally along the fore-aft shaft  24  such that the tabs  37  of the first engagement ring  36  can selectively engage the tabs  35  of the first driven gear  34 , thereby defining a first toothed clutch. Accordingly, when the first engagement ring  36  engages the first driven gear  34 , via the tabs  35 ,  37 , rotation of the first driven gear  34  translates into rotation of the fore-aft shaft  24 . 
   A first solenoid  38  is connected to the first engagement ring  36  and moves the first engagement ring  36  between engaged and disengaged positions. A plate  40  is non-rotatably and slidably mounted to the fore-aft shaft  24  between the first engagement ring  36  and the first solenoid  38 . In particular, the fore-aft shaft  24  has a spline, non-circular or otherwise irregular configuration with the plate  40  having a corresponding configuration such that the plate  40  cannot rotate relative to the fore-aft shaft  24 . The first solenoid  38  preferably includes a first plunger  42  which moves inward and outward to affect the sliding movement of the plate  40  and first engagement ring  36 . A first return spring is disposed about the fore-aft shaft  24  between the first engagement ring  36  and the first driven gear  34  for continuously biasing the first engagement ring  36  to the disengaged position. 
   The second coupling  26  includes a second driven gear  44  which rotates freely about a front worm drive  46 . The second driven gear  44  is in constant driving engagement with the second driving gear  18 . It should be appreciated that both the second driven gear  44  and the second driving gear  18  have co-acting teeth for transferring rotary motion of the second driving gear  18  to rotary motion of the second driven gear  44 . As best shown in  FIG. 4 , the front worm drive  46  includes a worm gear section and a shaft section. The second driven gear  44  rotates about the shaft section of the front worm drive  46 . The second driven gear  44  is prevented from sliding along the shaft section of the front worm drive  46  by either a stop on the shaft section and/or the gearing between the second driving gear  18  and the second driven gear  44 . 
   A plurality of tabs  45  extend from the second driven gear  44  to selectively engage a second engagement ring  48 . The second engagement ring  48  is non-rotatably and slidably mounted to the shaft section of the front worm drive  46  and includes corresponding tabs  49 . As will be appreciated, the second engagement ring  48  slides longitudinally along the front worm drive  46  such that the tabs  49  of the second engagement ring  48  can selectively engage the tabs  45  of the second driven gear  44 , thereby defining a second toothed clutch. Accordingly, when the second engagement ring  48  engages the second driven gear  44 , via the tabs  45 ,  49 , rotation of the second driven gear  44  translates into rotation of the front worm drive  46 . An appendage  50 , best shown in  FIG. 2 , extends outwardly from the second engagement ring  48  in an opposite direction of the tabs  49 . 
   Referring to  FIGS. 2 and 4 , a second solenoid  52  is connected to the second engagement ring  48  and moves the second engagement ring  48  between engaged and disengaged positions. Specifically, the second solenoid  52  includes a second plunger  54  which engages the appendage  50  of the second engagement ring  48 . The second plunger  54  moves inward and outward to affect the sliding movement of the second engagement ring  48 . The appendage  50  and second plunger  54  are formed and configured to create a virtually frictionless contact between the plunger  54  and ring  48  such that rotation of the second engagement ring  48 , and the appendage  50 , does not rotate the second plunger  54 . A second return spring is disposed about the shaft section of the front worm drive  46  between the second engagement ring  48  and the second driven gear  44  for continuously biasing the second engagement ring  48  to the disengaged position. The non-sliding nature of the second driven gear  44  provides a surface for the second return spring to react against for biasing the second engagement ring  48 . 
   As best shown in  FIG. 4 , a front fan gear  56  is non-rotatably mounted to the front lift shaft  28  and engages the front worm drive  46 . Teeth are disposed on the front fan gear  56  to engage the worm gear section of the front worm drive  46 . Accordingly, rotational movement of the front worm drive  46  translates into rotational movement of the front fan gear  56  and the front lift shaft  28 . The front fan gear  56  is designed and configured such that the front fan gear  56  may not over rotate the front lift shaft  28  beyond 180°. The configuration of the front fan gear  56  and the front worm drive  46  also creates a self-locking engagement. In other words, any back-driving of the front lift shaft  28  cannot be translated through the front fan gear  56  and front worm drive  46 . The self-locking front fan gear  56  and front worm drive  46  enable the transfer case assembly  10  to retain the front portion of the seat cushions in the stated position when the transfer case assembly  10  is not energized. 
   The third coupling  30  is substantially a mirror image of the second coupling  26 . In particular, the third coupling  30  includes a third driven gear  58  which rotates freely about a rear worm drive  60 . The third driven gear  58  is in constant driving engagement with the third driving gear  20 . It is appreciated that both the third driven gear  58  and the third driving gear  20  have co-acting teeth for transferring rotary motion of the third driving gear  20  to rotary motion of the third driven gear  58 . The rear worm drive  60  includes a worm gear section and a shaft section. The third driven gear  58  rotates about the shaft section of the rear worm drive  60 . The third driven gear  58  is prevented from sliding along the shaft section of the rear worm drive  60  by either a stop on the shaft section and/or the gearing between the third driving gear  20  and the third driven gear  58 . 
   A plurality of tabs  59  extend from the third driven gear  58  to selectively engage a third engagement ring  62 . The third engagement ring  62  is non-rotatably mounted to the shaft section of the rear worm drive  60  and includes corresponding tabs  63 . As will be appreciated, the third engagement ring  62  slides longitudinally along the rear worm drive  60  such that the tabs  63  of the third engagement ring  62  can selectively engage the tabs  59  of the third driven gear  58 , thereby defining a third toothed clutch. Accordingly, when the third engagement ring  62  engages the third driven gear  58 , via the tabs  59 ,  63 , rotation of the third driven gear  58  translates into rotation of the rear worm drive  60 . An appendage  64  extends outwardly from the third engagement ring  62  in an opposite direction of the tabs  63 . 
   A third solenoid  66  is connected to the third engagement ring  62  and moves the third engagement ring  62  between engaged and disengaged positions. Specifically, the third solenoid  66  includes a third plunger  68  which engages the appendage  64  of the third engagement ring  62 . The third plunger  68  moves inward and outward to affect the sliding movement of the third engagement ring  62 . The appendage  64  and third plunger  68  are formed and configured to create a virtually frictionless contact such that rotation of the third engagement ring  62 , and the appendage  64 , does not rotate the third plunger  68 . A third return spring is disposed about the shaft section of the rear worm drive  60  between the third engagement ring  62  and the third driven gear  58  for continuously biasing the third engagement ring  62  to the disengaged position. The non-sliding nature of the third driven gear  58  provides a surface for the third return spring to react against for biasing the third engagement ring  62 . 
   A rear fan gear  70  is non-rotatably mounted to the rear lift shaft  32  and engages the rear worm drive  60 . Teeth are disposed on the rear fan gear  70  to engage the worm gear section of the rear worm drive  60 . Accordingly, rotational movement of the rear worm drive  60  translates into rotational movement of the rear fan gear  70  and the rear lift shaft  32 . The rear fan gear  70  is designed and configured such that the rear fan gear  70  may not over rotate the rear lift shaft  32  beyond 180°. As discussed above with reference to the front fan gear  56 , the configuration of the rear fan gear  70  and the rear worm drive  60  creates a self-locking engagement. In other words, any back-driving of the rear lift shaft  32  cannot be translated through the rear fan gear  70  and rear worm drive  60 . The self-locking rear fan gear  70  and rear worm drive  60  enable the transfer case assembly  10  to retain the rear portion of the seat cushion in the stated position when the transfer case assembly  10  is not energized. 
   Plastic covers are preferably disposed over each of the parts of the transfer case assembly  10 . These plastic covers serve to both protect the components from contaminants and act as a safety guard. 
   Turning to  FIG. 5 , a seat track assembly is generally shown at  72 , which receives each of the fore-aft  24 , front lift  28  and rear lift  32  shafts. The seat track assembly  72  includes an upper track  74  slidably mounted to a lower track  76  by any suitable means known in the seat track art. The upper track  74  has a first end  74   a , a second end  74   b , and an upper surface  75  extending between the ends  74   a ,  74   b . A mounting bracket  78 , having a front bracket portion  80  and a rear bracket portion  82 , is secured to the upper surface  75  of the upper track  74 . 
   The fore-aft shaft  24  extending from the transfer case assembly  10  is received within a gearbox  84  for moving the seat track assembly  72  forward and rearward as will be discussed in greater detail below. 
   The front lift shaft  28  extending from the transfer case assembly  10  is rotatably supported in the front bracket portion  80 . A pair of front arms  86  are non-rotatably secured to the front lift shaft  28  for rotation therewith. A front seat cushion mount  88  is rotatably connected to the front arms  86  in a spaced apart relationship to the shaft  28  and is secured to the front portion of the seat cushion. Rotation of the front lift shaft  28  in turn rotates the front arms  86  and moves the front seat cushion mount  88  upward and downward. 
   The rear lift shaft  32  extending from the transfer case assembly  10  is rotatably supported in the rear bracket portion  82 . A pair of rear arms  90  are non-rotatably secured to the rear lift shaft  32  for rotation therewith. A rear seat cushion mount  92  is rotatably connected to the rear arms  90  in a spaced apart relationship to the shaft  32  and is secured to the rear portion of the seat cushion. Links  94  may also be provided between the rear arms  90  and the rear seat cushion mount  92  to provide additional height and adjustability. Rotation of the rear lift shaft  32  in turn rotates the rear arms  90  and moves the rear seat cushion mount  92  upward and downward. It should be appreciated that the rear seat cushion mount  92 , rear arms  90  and rear bracket portion  82  are substantially mirror images of the front seat cushion mount  88 , front arms  86  and front bracket portion  80 . 
   In light of the above described interconnections, it should be appreciated that the transfer case assembly  10  moves in unison with the upper track  74 . 
   Turning to  FIG. 6 , the fore-aft shaft  24 , gearbox  84  and associate parts are illustrated in greater detail. A short flexible shaft  96 , which may be a hollow plastic or rubber sleeve, a cable, or the like, is disposed in the lower track  76 . The gearbox  84  is of suitable construction for translating rotation of the fore-aft shaft  24  into rotation of the flexible shaft  96 . Rotation of the fore-aft shaft  24  is therefore transmitted through the gearbox  84  to the short flexible shaft  96  to rotate the short flexible shaft  96  in unison with the fore-aft shaft  24 . The short flexible shaft  96  extends from the gearbox  84  and is attached to a lead screw  98  having a plurality of threads. A pair of brackets  100  are non-rotatably supported on the lead screw  98 . The brackets  100  are mounted to the upper track  74  such that the lead screw  98 , short flexible shaft  96  and gearbox  84  move in unison with the upper track  74 . The short flexible shaft  96  allows for any misalignment between the lead screw  98  and the gearbox  84 . It should be appreciated that the flexible shaft  96  can be eliminated such that the lead screw  98  mounts directly to the gearbox  84 . 
   A nut  102 , having threads complementary to the threads of the lead screw  98 , is fixedly mounted to the lower track  76  with the lead screw  98  passing therethrough. Rotation of the short flexible shaft  96  in turn rotates the lead screw  98  through the nut  102 . The rotation of the lead screw  98  through the stationary nut  102  imparts the movement of the upper track  74 , and the seat cushion, relative to the lower track  76 . 
   To move the seat cushion in the foreword or rearward direction, the user actuates a control switch to a fore or aft position to energize the first solenoid  38 . It should be appreciated that the control switch is electrically connected to the solenoid  38 . Power is then applied to the motor  12  to rotate the drive shaft  14  and the first  16 , second  18  and third  20  driving gears. Due to the continuous contact, the first  34 , second  44  and third  58  driven gears also rotate. The first plunger  42  of the first solenoid  38  advances forward to push against the plate  40 . The plate  40  in turn pushes against the first engagement ring  36 . As the first plunger  42  advances both the plate  40  and the first engagement ring  36  move forward until the tabs  37  of the first engagement ring  36  engage the tabs  35  of the first driven gear  34 . At this point, the first engagement ring  36  and the first driven gear  34  are in running engagement. Due to the non-rotatable engagement of the first engagement ring  36  with the fore-aft shaft  24 , the rotational motion of the first driven gear  34  is now translated to the fore-aft shaft  24 . The rotation of the fore-aft shaft  24  is transmitted to the gearbox  84 , short flexible shaft  96  and lead screw  98 . 
   The switch will typically have two or four possible positions which correlate to a desired movement, i.e., forward, rearward, up, or down. There may also be multiple switches controlling one or more of the movements. Depending upon the particular actuation of the switch, which controls a desired movement, the lead screw  98  will rotate either clockwise or counter-clockwise to move the seat cushion forward or rearward. Upon release of the control switch, the power to the motor  12  is cut, followed by the disengagement of the first plunger  42 . The first return spring then biases the first engagement ring  36  out of coupling engagement with the first driven gear  34 . 
   Movement of a front portion of the seat cushion up or down requires a similar initial input by the user, i.e., actuating a control switch electrically connected to the second solenoid  52  to energize the second solenoid  52 . In turn, power is again applied to the motor  12  to rotate the drive shaft  14 , the first  16 , second  18  and third  20  driving gears and the corresponding first  34 , second  44  and third  58  driven gears. The second plunger  54  moves forward and engages the abutment of the second engagement ring  48  to push the second engagement ring  48  forward. The tabs  47  of the second engagement ring  48  then engage the tabs  43  of the second driven gear  44  to rotate the front worm drive  46 . The front worm drive  46  is now in running engagement with the front fan gear  56 . The rotational movement of the front fan gear  56  rotates the front lift shaft  28 . Depending upon the control of the switch which correlates to the desired movement, up or down, the front lift shaft  28  is rotated either clockwise or counter-clockwise to move the front arms  86  and front seat cushion mount  88  upward or downward. Upon disengagement of the control switch, the power to the motor  12  is cut, followed by the disengagement of the second plunger  54 . The second return spring then biases the second engagement ring  48  out of coupling engagement with the second driven gear  44 . As discussed above, the front fan gear  56  and front worm drive  46  lock the front portion of the seat cushion in the stated position. 
   Movement of a rear portion of the seat cushion up or down is substantially similar to the upward and downward movement of the front portion of the seat cushion. Initial input by the user, i.e., actuating a control switch, energizes the third solenoid  66 . In turn, power is again applied to the motor  12  to rotate the drive shaft  14 , the first  16 , second  18  and third  20  driving gears and the corresponding first  34 , second  44  and third  58  driven gears. The third plunger  68  moves forward and engages the abutment of the third engagement ring  62  to push the third engagement ring  62  forward. The tabs  63  of the third engagement ring  62  then engage the tabs  59  of the third driven gear  58  to rotate the rear worm drive  60 . The rear worm drive  60  is now in running engagement with the rear fan gear  70 . The rotational movement of the rear fan gear  70  rotates the rear lift shaft  32 . Depending upon the desired movement, up or down, the rear lift shaft  32  is rotated either clockwise or counter-clockwise to move the rear arms  90  and rear seat cushion mount  92  upward or downward. Upon disengagement of the control switch, the power to the motor  12  is cut, followed by the disengagement of the third plunger  68 . The third return spring then biases the third engagement ring  62  out of coupling engagement with the third driven gear  58 . As discussed above, the rear fan gear  70  and rear worm drive  60  lock the rear portion of the seat cushion in the stated position. 
   It should be appreciated that various control switches may be connected to the solenoids in various configurations such that the forward and rearward movement of the seat cushion as well as the upward and downward movement of the front and rear portions of the seat cushion may operate independently of each other or in concert with each other. The subject invention therefore creates a highly manipulatable seat cushion with the use of a single motor  12 . 
   The invention has been described in an illustrative manner, it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. It now apparent to those skilled in the art that many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that the invention may be practiced otherwise than as specifically described.