Abstract:
An adjustable memory track assembly for a vehicle seat has a lower rail adapted to be secured relative to a vehicle frame, and an upper rail adapted to support the seat for fore/aft sliding movement relative to the lower rail. The adjustable memory track assembly also has a track lock assembly operable via a first actuator between a locked, engaged state wherein relative movement between the lower and upper rails is resisted, and an unlocked, disengaged state wherein the seat can be slid to and then locked in a user-selected position. A memory module is operable via a second actuator to record the user-selected position. The second actuator is also operatively connected to disengage the track lock assembly to allow forward movement of the seat from the user-selected location to a forward location, and thereafter allow rearward movement of the seat back to, but not past, the user-selected location. The adjustable memory track assembly is characterized in that the memory module is provided with a blocking element to prevent rearward movement of the seat past the user-selected position independent of the locking state of the track lock assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/294,749, filed Jan. 13, 2010, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates in general to adjustable seats and in particular to vehicle seats whose position may be adjusted fore and aft. Vehicles such as passenger cars typically include seats for the use of the driver and other occupants. In many vehicles, the position of the seats may be adjusted for the comfort of the occupant. The options to adjust the position of a seat typically include the ability to move the seat in a fore and aft direction by operation of a track assembly which mounts the seat to the vehicle floor. 
     Some vehicles include the option of moving the seats in the first row in order to facilitate access to the second row. This is known as an easy entry option and is commonly seen in two-door vehicles. The easy entry allows the generally upright back portion of the seat to be dumped, or pivoted from its normal use position to a more forward position, in order to facilitate access to the space behind the seat. Additionally, the track assembly may be actuated so that the seat may be moved forward. Often, the seat is moved to its most forward position. This allows a person to more easily gain access to the space located behind the seat. When the seat no longer has to be in the dumped position, the seat back may be raised to its use position, and the seat may be moved back from its most forward position. This allows an occupant to comfortably sit in the seat. 
     An occupant of a seat will typically position that seat in the location that is most comfortable for him or her. When the seat is dumped, it is moved from that selected position. It is desirable that when the seat is raised from the dumped position that it return to the desired position that the user previously selected. This way the seat is in the location that is most comfortable for the occupant without the occupant having to adjust the seat again. 
     SUMMARY OF THE INVENTION 
     This invention relates to an adjustable memory track assembly for a vehicle seat. The track assembly has a lower rail adapted to be secured relative to a vehicle frame, and an upper rail adapted to support the seat for fore/aft sliding movement relative to the lower rail. The adjustable memory track assembly also has a track lock assembly operable via a first actuator between a locked, engaged state wherein relative movement between the lower and upper rails is resisted, and an unlocked, disengaged state wherein the seat can be slid to and then locked in a user-selected position. A memory module is operable via a second actuator to record the user-selected position. The second actuator is also operatively connected to disengage the track lock assembly to allow forward movement of the seat from the user-selected location to a forward location, and thereafter allow rearward movement of the seat back to, but not past, the user-selected location. The adjustable memory track assembly is characterized in that the memory module is provided with a blocking element to prevent rearward movement of the seat past the user-selected position independent of the locking state of the track lock assembly. 
     This invention further relates to an adjustable memory track assembly that includes a first rail and a second rail adapted for fore/aft sliding movement relative to the first rail. A track lock assembly is operable between a locked, engaged state wherein relative movement between the first and second rails is resisted, and an unlocked, disengaged state wherein relative movement between the first and second rails is not resisted. A memory module is operable to record a user-selected position. The memory module is provided with a blocking mechanism adapted to prevent movement of the second rail in the aft direction past the user-selected position independent of the locking state of the track lock assembly. 
     This invention further relates to an adjustable memory track assembly that includes a first rail and a second rail adapted for fore/aft sliding movement relative to the first rail. A track lock assembly is operable between a locked, engaged state wherein relative movement between the first and second rails is resisted, and an unlocked, disengaged state wherein relative movement between the first and second rails is not resisted. A memory module is operable to record a user-selected position. The memory module is provided with a blocking mechanism adapted to prevent movement of the second rail in the aft direction past the user-selected position independent of the locking state of the track lock assembly. The memory module includes a memory wheel mounted relative to one of the second rail and first rail. The memory wheel includes a plurality of teeth adapted to engage openings in a track mounted relative to the other of the second rail and first rail when the memory module is operated. At least one of the plurality of teeth adapted to support a load to prevent rearward movement of the second rail past the user-selected position. The memory module includes a threaded axle attached to the memory wheel and a memory nut that includes a threaded opening adapted to engage the threaded axle. The memory nut moves axially along the threaded axle when the seat is moved away from the user-selected location. The blocking element comprises a first memory surface mounted relative to the memory nut and a second memory surface mounted relative to the memory wheel. The first memory surface and the second memory surface are adapted so that the first memory surface is engaged with the second memory surface when the seat is at the user-selected position. The first memory surface is also engaged with the second memory surface when the seat is a prescribed distance from the user-selected position. 
     Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a rear perspective view of a bucket-type seat. 
         FIG. 2  is a perspective view of a track assembly of the seat of  FIG. 1 . 
         FIG. 3  is a perspective view of a portion of the seat track assembly of  FIG. 2 , showing a latch assembly and an easy entry assembly. 
         FIG. 4  is a cross sectional view taken along line  4 - 4  of  FIG. 3 .  FIG. 4  illustrates a track lock engaged and a memory module disengaged. 
         FIG. 5  is a cross sectional view similar to that shown in  FIG. 4 .  FIG. 5  illustrates the track lock disengaged and the memory module engaged. 
         FIG. 6  is a cross sectional view similar to that shown in  FIG. 5 .  FIG. 6  illustrates the memory module engaged and the seat moved forward of a memory point. 
         FIG. 7  is an exploded, perspective view of a portion of the memory module of  FIGS. 4-6 . 
         FIG. 8  is an exploded, perspective view of a portion of the memory module of  FIG. 7 , with the view taken from the opposite direction to illustrate details on the opposite sides of some components. 
         FIG. 9  is a side view of teeth of a memory wheel engaged with a track. 
         FIG. 10  is a side view similar to that shown in  FIG. 9 , when the memory wheel has been moved relative to the track. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, there is illustrated in  FIG. 1  a perspective view of a bucket seat  10 . The illustrated bucket seat  10  is a type commonly installed in the front row of seats in passenger vehicles. The bucket seat  10  includes a seat portion  12  and a backrest  14 . The seat portion  12  and the backrest  14  are typically cushioned and upholstered for aesthetics and the comfort of seat occupants. The seat portion  12  and the backrest  14  may be upholstered with leather, fabric, or other desired materials. The bucket seat  10  is used for illustrative purposes only, and may be sized to accommodate any number of occupants or may be a bench-type seat. 
     Referring now to  FIG. 2 , there is shown a track assembly  16 . The track assembly  16  includes a pair of first rails  18  and a pair of second rails  20 . The first rails  18  are secured relative to a floor or a frame of a vehicle (not shown). The second rails  20  are mounted relative to the seat portion  12  of the bucket seat  10 . The second rails  20  are attached to the first rails  18  in order to allow the second rails  20  to move relative to the first rails  18  in the directions indicated by arrows  30  and  30   a . This allows adjustment of the position of the bucket seat  10  in the vehicle. It should be appreciated that within the vehicle, this allows fore-and-aft movement of the second rails  20  relative to the first rails  18 . However, the track assembly  16  may be adapted to allow relative movement in some other direction, if desired. 
     The track assembly  16  includes a catch assembly, indicated generally at  22 , mounted relative to one of the second rails  20 . The seat track assembly also includes a catch and memory assembly, indicated generally at  24 , mounted relative to the other of the second rails  20 . The catch assembly  22  and the catch and memory assembly  24  are adapted to selectively lock or prevent movement of the respective second rail  20  relative to the respective first rail  18 , as will be described below. The catch assembly  22  and the catch and memory assembly  24  are operatively connected by a connection tube  26 . The connection tube  26  is adapted to help the catch assembly  22  and the catch and memory assembly  24  to selectively lock in unison. 
     The catch assembly  22  and the catch and memory assembly  24  are also operatively connected by a comfort adjustment bar  28 . The comfort adjustment bar is adapted to allow an occupant of the seat to selectively unlock or release the catch assembly  22  and the catch and memory assembly  24  in order to allow the occupant to adjust the position of the seat. The comfort adjustment bar  28  is a first actuator used to manually operate the catch assembly  22  and the catch and memory assembly  24 . The catch assembly  22  and the catch and memory assembly  24  will be described in detail below. 
     Referring to  FIG. 3 , a detailed perspective view of the catch and memory assembly  24  is shown. The catch and memory assembly  24  includes a support bracket  32 . The illustrated support bracket  32  is made of steel and is welded to the second rail  20 ; however, the support bracket  32  may be made of other desired materials, and may be attached to the second rail  20  by other desired fasteners, such as by pins, rivets, adhesives, or threaded fasteners. The catch and memory assembly  24  also includes an activation bracket  34 . The activation bracket is mounted for pivotal movement relative to the support bracket  32 . The connection tube  26  is fixed relative to the support bracket  32 . The activation bracket  34  may be fixed to the connection tube  26  by any desired fasteners, including welding, pins, rivets, adhesives, or threaded fasteners. A spring  36  is adapted to provide a force to bias the activation bracket relative to the support bracket in the direction indicated by the arrow  38 . 
     The catch and memory assembly  24  also includes a track lock sled or a first sled  40   a  and a memory lock sled or a second sled  40   b . The first sled  40   a  and the second sled  40   b  are mounted for sliding movement relative to the support bracket  32 . A first sled spring  42   a  is adapted to bias the first sled  40   a  relative to the support bracket  32  in the direction indicated by the arrow  44 . A second sled spring  42   b  is adapted to bias the second sled  40   b  relative to the support bracket  32  in the direction indicated by the arrow  44 . 
     The catch and memory assembly  24  is operatively connected to the backrest  14  by a Bowden cable  46 . The Bowden cable  46  is a second actuator used to operate the catch assembly  22  and the catch and memory assembly  24 . The Bowden cable  46  is supported by the support bracket  32  by a support flange  48 . When the backrest  14  is dumped, or pivoted from a generally upright use position to a more forward position in order to facilitate access to a space behind the bucket seat  10 , the Bowden cable  46  applies a force to the activation bracket  34  in the direction indicated by the arrow  50 . The force  50  applied by the Bowden cable  46  is sufficient to overcome the biasing force of the spring  36 . Therefore, when the backrest  14  is dumped, the activation bracket  34  is rotated in an activation direction, indicated by arrow  52 . The effects of this will be explained in reference to the following figures. 
     Referring now to  FIG. 4 , a cross sectional view of the catch and memory assembly  24  is shown.  FIG. 4  illustrates the catch and memory assembly  24  when the backrest  14  is in its raised position. The activation bracket  34  is shown in a disengaged position. In addition to the components previously described, the catch and memory assembly  24  includes a track lock assembly, shown schematically at  54 . The track lock assembly  54  will not be described in detail, but may include any desired assembly that can releasably prevent relative movement between the first rail  18  and the second rail  20 . When the track lock assembly  54  is engaged, it prevents movement of the second rail  20  relative to the first rail  18 . The track lock assembly  54  includes a lock activation pin  56 . The lock activation pin  56  may be actuated to disengage the track lock assembly  54 . The track lock assembly  54  also includes a lock activation member  58  operatively connected to the comfort adjustment bar  28 . The lock activation member  58  may be actuated to disengage the track lock assembly  54 , thereby permitting fore and aft movement of the bucket seat  10 . The lock activation pin  56  and the lock activation member  58  are shown in their respective non-actuated positions in  FIG. 4 . Therefore, the track lock assembly  54  is engaged in  FIG. 4  and the second rail  20  is unable to move relative to the first rail  18 . 
     The catch and memory assembly  24  also includes a memory module, indicated generally at  60 . The memory module  60  includes a memory activation pin  62 . The memory activation pin  62  may be actuated to engage the memory module  60 . The operation of the memory module  60  will be described in detail below. 
     The catch and memory assembly  24  also includes a sled block  184 . The sled block  184  is mounted to pivot relative to the support bracket  32  about a block pivot  186 . A block spring  188  is adapted to bias the sled block  184  in a blocking direction, indicated by arrow  190 . A protrusion  192  on the sled block  184  is adapted to engage with the first sled  40   a  in order to prevent movement of the sled block  184  in the direction indicated by arrow  190  beyond the position shown in  FIG. 4 . 
     Referring now to  FIG. 5 , a cross sectional view similar to that shown in  FIG. 4  is illustrated. The catch and memory assembly  24  is shown in the configuration it is in when the backrest  14  has been dumped. As shown in  FIG. 5 , the Bowden cable  46  has applied a force to the activation bracket  34  and the activation bracket  34  has been rotated in the activation direction  52  (as shown in  FIG. 3 ). The activation bracket  34  is shown in an engagement position. The activation bracket  34  is adapted to engage the lock activation pin  56  when the activation bracket  34  is in the engagement position. Thus, the activation bracket  34  actuates the lock activation pin  56  causing the track lock assembly  54  to disengage. 
     The activation bracket  34  also includes a sled engagement surface  66 . The sled engagement surface  66  is adapted to move the first sled  40   a  when the activation bracket  34  is in the engagement position. The sled engagement surface  66  applies a force to the first sled  40   a  sufficient to overcome the biasing force of the first sled spring  42   a  (shown in  FIG. 3 ). Thus, the sled engagement surface  66  moves the first sled  40   a  to a sled activated position, in the direction indicated by arrow  68 . The first sled  40   a  is adapted so that when the first sled  40   a  is moved to the activated position, is moves the second sled  40   b  to an activated position, also in the direction indicated by the arrow  68 . It should be appreciated that the second sled  40   b  is moved against the force of the second sled spring  42   b  (shown in  FIG. 3 ). The first sled  40   a  and the second sled  40   b  are shown in their respective activated positions in  FIG. 5 . 
     The second sled  40   b  includes a memory engagement surface  70 . The memory engagement surface  70  is adapted to engage the memory activation pin  62  when the second sled  40   b  is in the activation position. When the memory activation pin  62  is engaged, the memory module  60  is moved to a memory activation position, in the direction indicated by arrow  72 . The operation of the memory module  60  will be described in detail below. 
     The second sled  40   b  also includes a sled catch  74 . The sled catch  74  is adapted to interoperate with a sled lock  76  in order to releasably lock the second sled  40   b  in the activated position. The illustrated sled catch  74  is an integral component of the plastic second sled  40   b  and the illustrated sled lock  76  is a plastic piece that is fixed relative to the comfort adjustment bar  28 . It should be appreciated that the comfort adjustment bar is movable upwards and downwards (as viewed in  FIG. 5 ) and is biased in the upwards direction, therefore, the sled lock  76  is also movable. The sled lock  76  may be made of other desired materials, such as metal, and may not be connected to the comfort adjustment bar  28 , if desired. The sled catch  74  and the sled lock  76  include cam surfaces adapted so that the sled lock  76  is pushed downward when the second sled  40   b  moves in the direction indicated by the arrow  68 . This allows the second sled  40   b  to move into the activated position. The sled catch  74  and the sled lock  76  further include engaging surfaces that prevent the second sled  40   b  from moving away from the activated position. It should be appreciated that while one embodiment of the sled catch  74  and the sled lock  76  has been described, the sled catch  74  and the sled lock  76  may be made of other materials, and may be designed to interact in a manner other than that specifically illustrated, if desired. 
     When the first sled  40   a  is in the activated position, the sled block  184  is no longer engaged with the first sled  40   a . The sled block  184  is therefore biased further in the direction indicated by the arrow  190  by the block spring  188 . The sled block  184  will move in the direction indicated by the arrow  190  until the sled block  184  engages with a memory nut  152  of the memory module  60 . The memory nut  152  will be described in detail below. 
     Referring now to  FIG. 7 , there is shown an exploded, perspective view of the memory module  60 . The memory module  60  includes a memory mounting bracket  96  that is adapted to be attached to the second rail  20  by rivets  98 . The memory mounting bracket  96  may be attached to the second rail  20  by other desired fasteners, such as by pins, adhesives, threaded fasteners, or by welding. The memory module  60  also includes a memory arm  100 . The memory arm  100  is attached for pivoting movement relative to the memory mounting bracket  96  by a pivot shaft  102 . The memory module  60  includes a memory spring  104  that biases the memory arm  100  in a memory deactivation direction, indicated by the arrow  92 . The illustrated memory spring  104  is a coil spring disposed around a sleeve  108  that is placed around the pivot shaft  102 . It should be appreciated that the memory spring  104  may be any desired biasing member, such as a resilient member or a counter weight. 
     The memory activation pin  62  is attached to the memory arm  100 . It should be appreciated that when the second sled  40   b  is moved to the activated position (as shown in  FIG. 5 ) the memory arm  100  is moved to the memory activation position (as indicated by the arrow  72  in  FIG. 5 ) over the biasing force of the memory spring  104 . 
     In further reference to  FIG. 7 , the memory module  60  includes a memory wheel  110 . The memory wheel  110  is mounted for pivotal movement relative to the memory arm  100 . The memory wheel includes a plurality of teeth  112 . The illustrated memory wheel  110  is a metal wheel with a plastic over mold. It should be appreciated that the memory wheel  110  may be made of other desired materials. 
     The memory module  60  also includes a face place  114 . A first side  116  of the face plate  114  includes an axle  118  and a stub  120 . The axle  118  is adapted to be held in an axial opening  122  defined on the memory arm  100 . The stub  120  is adapted to be held in a stub opening  124  defined on the memory arm  100 . Therefore, the face plate  114  is fixed relative to the memory arm  100 . 
     A first side  126  of the memory wheel  110  includes a spring space  128 . A wheel hub  130  is located at the axis of the memory wheel  110  within the spring space  128 . As shown in reference to  FIG. 8 , a second side  132  of the face plate  114  includes a face plate hub  134 . The face plate hub  134  is adapted to cooperate with the wheel hub  130  to allow the memory wheel  110  to rotate relative to the face plate  114  when the memory module  60  is assembled. The face plate  114  fits onto the memory wheel  110  such that the face plate  114  covers the spring space  128 . 
     The memory wheel  110  also includes a clock spring  136 . The clock spring  136  is located within the spring space  128 . The clock spring  136  includes a first end  138  and a second end  140 . The first end  138  of the clock spring  136  is fixed relative to the memory wheel  110  at a wheel attachment point  142 . The second end  140  of the clock spring  136  is fixed relative to the face plate  114  at a face plate attachment point  144 . The operation of the clock spring  136  will be described in detail below. 
     As shown in  FIG. 8 , a second side  146  of the memory wheel  110  includes a threaded axle  148 . The threaded axle  148  is coaxial with the center of the memory wheel  110 . A second axle  118   a  is located on the end of the threaded axle  148 , and is coaxial with the axle  118 . The second axle  118   a  is adapted to be held by the memory arm  100  in order to allow rotation of the memory about the axle  118  and the second axle  118   a . Alternatively, the axle  118  and the second axle  118   a  may be replaced by a single axle that passes through the memory wheel  110 . The second side  146  of the memory wheel  110  also includes a wheel end stop  150 . The wheel end stop  150  is a raised face generally perpendicular to the second side  146  of the memory wheel  110 . The wheel end stop  150  is generally parallel with the axis of the memory wheel  110 . It should be appreciated that the wheel end stop  150  may have a different configuration or orientation from that illustrated. Also, the memory wheel  110  may include more than one wheel end stop  150 . For example, there may be two wheel end stops located on the same diameter of the second side  146  but on opposite sides of the threaded axle  148 . The function of the memory wheel end stop  150  will be described below. 
     Referring back to  FIG. 7 , the memory module  60  also includes a memory nut  152 . The memory nut  152  is a molded metal piece, but may be made of other desired material and methods. The memory nut  152  includes a threaded opening  154  that is adapted to fit onto the threaded axle  148  of the memory wheel  110 . The memory nut  152  also includes a stop hook  156  that is adapted to engage a stop shaft  158 . The memory nut  152  is able to slide freely along the stop shaft  158 . The stop shaft  158  is adapted to be fixed relative to the memory arm  100  at a stop mount  160 . 
     The memory nut  152  also includes a nut end stop  162 . The nut end stop  162  is a raised face generally perpendicular to memory nut  152 . The nut end stop  162  is generally parallel with the axis of the threaded opening  154 . It should be appreciated that the nut end stop  162  may have a different configuration or orientation from that illustrated. Also, the memory nut  152  may include more than one nut end stop  162 . There may be one nut end stop  162  to complement each wheel end stop  150 , although this is not required. The function of the nut end stop  162  will be described below. 
     When the memory module  60  is assembled, the face plate  114  is secured relative to the memory arm  100  by the axle  118  and the stub  120 . The memory wheel  110  is connected for rotational movement relative to the face plate  114  by the cooperation of the wheel hub  130  and the face plate hub  134 . An outer end  164  of the threaded axle  148  is supported by rotational movement by the memory arm  100 . The memory nut  152  is supported by the threaded axle  148  and the stop shaft  158 . It should be appreciated that the memory nut  152  is able to rotate relative to the threaded axle  148 , but the stop hook  156  will engage the stop shaft  158  to limit the range of motion of the memory nut  152 . The memory nut  152  includes a nut spring hole  170  that is adapted to hold one end of a nut spring  172 . The nut spring  172  is also attached to the memory arm  100  of the memory module  60   a  at an arm spring hole  178 . The nut spring  172  provides a force that biases the memory nut  152  to rotate about the threaded axle  148  in a direction indicated by the arrow  180 . It should be appreciated that rotation of the memory nut  152  is prevented when the stop hook  156  engages with the stop shaft  158 . 
     The memory module  60  is configured so that, as the memory wheel  110  rotates, the memory nut  152  slides along the threaded shaft  148  and the stop shaft  158 . The memory nut will then move farther from or closer to the memory wheel  110  depending on which direction the memory wheel  110  is turning. The memory nut  152  is able to approach the memory wheel  110  until the nut end stop  162  engages the wheel end stop  150 . The engagement of these two faces prevents the memory nut  152  from moving any closer to the memory wheel  110 . It should be appreciated that this also prevents further rotation of the memory wheel  110  in the direction that would cause the memory nut  152  to approach the memory wheel  110 . Therefore, the memory nut  152  acts as a blocking mechanism to prevent rotation of the memory wheel  110  in a particular direction beyond a particular point. When the nut end stop  162  engages the wheel end stop  150 , the memory module  60  is said to be in the zero position. The clock spring  136  is pre tensioned when the memory module is in the zero position, although this is not necessary. 
     Referring back to  FIG. 5 , when the memory module  60  is activated, the memory wheel  110  is moved so that at least one of the teeth  112  engages with openings in a track  166 . The location of the second rail  20  relative to the first rail  18  when the memory module  60  is activated is the memory point. When first rail  18  and the second rail  20  are in these relative positions, the memory module  60  is in the zero position. When the second rail  20  is moved in the direction indicated by the arrow  30 , the engagement of the teeth  112  with the track  166  causes the memory wheel  110  to rotate. The rotation of the memory wheel  110  causes rotation of the threaded axle  148 . The rotation of the threaded axle  148  will cause rotation of the memory nut  152 . The memory nut  152  will rotate along with the threaded axle  148  until the memory nut engages the memory arm  100 . 
     Referring to  FIG. 9 , a side view of the teeth  112  engaged with the openings in the track  166  is shown. In the position shown in  FIG. 9 , the memory module is in the zero position and at the memory point. As can be seen, one of the plurality of teeth  112  is a stop tooth  112   a . The stop tooth  112   a  includes a tooth stop surface  194  that is adapted to engage with one of a plurality of track stop surfaces  196  on the track  166 . In the illustrated embodiment, the tooth stop surface  194  and the track stop surfaces  196  are planar surfaces; however, these surfaces may have other desired shapes. In the illustrated embodiment, only one of the plurality of teeth  112  is a stop tooth  112   a . The rest of the plurality of teeth  112  do not include the tooth stop surface  194 . Alternatively, more than one of the plurality of teeth  112  may include the tooth stop surface  194 , if desired. It should be appreciated that each track stop surface  196  corresponds to a position that may be the user-selected position. The spacing between the track stop surfaces  194  corresponds to the adjustment increment of the track lock assembly  54 . Therefore, in all positions that the track lock assembly  54  can lock the second rail  20  relative to the first rail  18 , one of the track stop surfaces  196  is available to engage the tooth stop surface  194 . 
     Referring to  FIG. 10 , a view similar to that shown in  FIG. 9  is illustrated, when the memory wheel  110  has been moved in the direction indicated by the arrow  30 . Each of the plurality of teeth  112  includes a leading edge  198 . As the memory wheel  110  moves, leading edge  198  engages with the track  166 , causing the memory wheel  110  to rotate. The clock spring  136  provides a biasing force on the memory wheel  110  in the direction indicated by the arrow  200 . As a result, only the leading edges  198  of the teeth  112  drive rotation of the memory wheel  110 . When the memory wheel  110  is moved in the direction indicated by the arrow  30   a , the leading edge  198  will remain engaged with the track  166  as the memory wheel  110  rotates. Referring back to  FIGS. 7 and 8 , it should be appreciated that when the wheel end stop  150  engages the nut end stop  162 , the memory wheel  110  will no longer rotate, either due to engagement with the track  166  or due to the biasing force of the clock spring  136 . Therefore, as shown in  FIG. 9 , the tooth stop surface  194  will engage the track stop surface  196  as the memory wheel  110  moves in the direction indicated by the arrow  30   a , and further movement of the memory wheel in the direction  30   a  is prevented. 
     Referring now to  FIG. 6 , a cross sectional view similar to that shown in  FIG. 5  is illustrated. The catch and memory assembly  24  is shown in the configuration it is in when the second rail  20  have been moved relative to the first rail  18  a prescribed distance in the direction indicated by the arrow  30 . In this illustrated embodiment, the prescribed distance is within the range of approximately 3 millimeters to 6 millimeters. However, the prescribed distance may be greater or less, if desired. As shown, the rotation of the memory nut  152  allows the sled block  184  to be moved further in the direction indicated by the arrow  190  by the block spring  188 . The sled block  184  will move in the direction indicated by the arrow  190  so that the sled block  184  remains engaged with the memory nut  152 . 
     At this point, the memory nut  152  is unable to rotate further with threaded axle  148 . If the second rail  20  is moved relative to the first rail  18  in the direction indicated by the arrow  30 , the memory nut  152  will remain in its position relative to the memory arm  100  and will rotate relative to the threaded axle  148 . This will cause the memory nut  148  to move away from the memory wheel  110 , as previously described in reference to  FIGS. 7 and 8 . It should be appreciated that the memory wheel  110  is also rotating relative to the face plate  114 . As a result, the clock spring  136  is wound more tightly as the memory nut  152  is moved further from the memory wheel  110 . 
     In the position illustrated in  FIG. 6 , the backrest  14  of the seat  10  has been dumped, and the seat  10  has been moved in the forward direction in order to provide easier access to the space behind the seat  10 . As shown, the track lock assembly  54  remains disengaged because the activation bracket  34  continues to actuate the lock activation pin  56 . Thus, relative movement between the first rail  18  and the second rail  20  is possible. If the backrest  14  is raised when the catch and memory assembly  24  is in this position, then the Bowden cable  46  will no longer apply a force to the activation bracket  34 . However, the activation bracket  34  will remain in the position shown in  FIG. 6 . Rotation of the activation bracket  34  relative to the support bracket  34  is constrained because the engagement surface  66  of the activation bracket  34  is engaged with the first sled  40   a . The first sled  40   a  locked in the activated position by the sled block  184 . As shown, the protrusion  192  of the sled block  184  is engaged with the first sled  40   a , and prevents movement of the first sled  40   a  away from the activated position. As a result, the activation bracket  34  remains in its activated position, and the track lock assembly  54  remains disengaged. 
     When the seat  10  is moved in the direction indicated by arrow  30   a  back toward the memory point, the memory wheel  110  will be rotated in the opposite direction and the memory nut  152  will be moved back toward the memory wheel  110 . When the seat is approximately 3 to 6 millimeters from the memory point, the catch and memory assembly  24  will be in the configuration shown in  FIG. 6 . It should be appreciated that at this point, the end stop  150  of the memory wheel  110  and the nut end stop  162  of the memory nut (seen in  FIGS. 7 and 8 ) are in contact with each other. At this point, the memory nut  152  is unable to move any closer to the memory wheel  110 . As the seat  10  is moved further toward the memory point, the memory nut  152  therefore rotates along with the memory wheel  110 . The memory nut  152  rotates until the stop hook  156  engages the stop shaft  158 . At this point, the memory module  60  is in the zero position. It should be appreciated that when the memory nut  152  is rotated, it also rotates the sled block  184  to the position illustrated in  FIG. 5 . At this point, the protrusion  192  of the sled block  184  is no longer engaged with the first sled  40   a , and the first sled  40   a  may be moved away from the activated position in the direction  44  by the first sled spring  42   a  (as described and shown above in reference to  FIG. 3 ). Thus, the activation bracket  34  is also able to move out of its activated position, and will no longer actuate the activation pin  56 . Therefore, the track lock assembly  54  will engage and will prevent further relative movement between the first rail  18  and the second rail  20 . The seat  10  is now locked in the memory position. 
     It should be appreciated that the second sled  40   b  remains in its activated position, due to the engagement of the sled catch  74  and the sled lock  76 . Therefore, the memory module  60  remains in its activated position. 
     The seat occupant may use the comfort adjustment bar  28  in order to adjust the position of the seat  10  in the vehicle. The comfort adjustment bar  28  is adapted so that use of the comfort adjustment bar will disengage the track lock assembly  54 . This allows the occupant to move the second rail  20  relative to the first rail  18 . The comfort adjustment bar  28  is also adapted so that use of the comfort adjustment bar will disengage the sled lock  76  and the sled catch  74 . Thus, the second sled  40   b  is no longer locked in its activated position, and the second sled  40   b  will be moved away from its activated position by the second sled spring  42   b  (shown in  FIG. 3 ). When the second sled  40   b  is no longer in its activated position, it no longer engages the memory activation pin  62  and the catch and memory assembly is in the configuration illustrated in  FIG. 4 . The memory module is able to return to a non-activated state. Thus, the seat may be moved both forward and backward without being blocked by the memory module. 
     Operation of the bucket seat  10  will now be described in order to clarify the operation of the track assembly  16  and the catch and memory assembly  24 . An occupant of the bucket seat  10  may use the comfort adjustment bar  28  to release the track lock assembly  54 . Use of the comfort adjustment bar  28  also releases the second sled  40   b , and sets the memory module  60  to the zero position. This allows the occupant to move the bucket seat  10  fore and aft to a user-selected position. When the bucket seat  10  is at the user-selected position, the comfort adjustment bar  28  is released and the track lock assembly  54  engages. 
     As shown in  FIG. 1 , the illustrated bucket seat  10  may include a number of handles  168 . The handles  168  are included for illustrative purposes only, and are representative of various non-limiting options for actuating the mechanism (not shown) used to move the backrest to the dumped position. When a user wishes to gain access to the space behind the bucket seat  10 , one of the handles  168  may be used to actuate the easy entry. The handle  168  releases the backrest  14 , allowing it to move from its use position to a more forward, easy entry position. It should be appreciated that using the handle may cause the backrest  14  to be dumped or biased toward the easy entry position, or may require the user to move it manually to the easy entry position. The movement of the backrest  14  to the easy entry position causes the Bowden cable  46  (shown in  FIG. 3 ) to apply a force to the activation bracket  34 . This force causes the activation bracket  34  to rotate in the direction  52 . 
     Referring now to  FIG. 4 , the activation bracket  34  is shown in this rotated state. Rotation of the activation bracket  34  depresses the lock activation pin  56 , which disengages the track lock assembly  54 . It should be appreciated that the bucket seat  10  may be biased in a forward direction, in order to facilitate access to the space behind the bucket seat  10 . Rotation of the activation bracket  34  also moves the first sled  40   a  in the direction  68  to its activated position. The first sled  40   a  in turn moves the second sled  40   b  to its activated position. The second sled  40   b  activates the memory module  60  and causes the memory wheel  110  to engage the track  166 . The activation of the memory module  60  records the user-selected position or the memory point of the bucket seat  10 . The bucket seat  10  may now be moved in the forward direction, indicated by arrow  30 . 
     It should be appreciated that the bucket seat  10  cannot be moved in the aft direction, because movement in that direction is blocked by the memory module  60 . If an attempt is made to move the bucket seat  10  in the rearward direction, the tooth  112  of the memory wheel  110  will engage with the track  116 , and a force will be applied to turn the memory wheel  110 . However, the end stop  150  of the memory wheel  110  is engaged with the nut end stop  162  of the memory nut. This acts as the blocking mechanism to prevent further rotation of the memory wheel  110 . Therefore, the memory module  60  prevents rearward movement of the bucket seat  10 . Because the teeth  112  of the memory wheel  110  are engaged with the track  166 , the rearward force will be supported by at least one of the teeth  112  of the memory wheel. It should be appreciated that the memory module  60  only prevents rearward movement past the user-selected position, and the bucket seat  10  may be moved forward of the user-selected position, and rearward up to the user-selected position, without that movement being prevented by the memory module  60 . 
     When it is desired to return the bucket seat  10  to its original posture, the backrest  14  is raised to its use position. When the backrest  14  is raised to its use position and the seat is returned to the memory point. At this point, the first memory sled is no longer held in its activated position by either the activation bracket  34  or the sled block  184 . Therefore, the first sled  40   a  and the activation bracket  34  both move out of their respective activated positions and the track lock assembly  54  engages, preventing further movement of the bucket seat. 
     It should be appreciated that while the memory module  60  and the catch and memory assembly  24  have been described for use with a particular seat track assembly, the memory module  60  or the catch and memory assembly  24  may be used with any desired track assembly. 
     The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.