Abstract:
Disclosed is a seat rail structure of a vehicle seat. The seat rail structure may include a lower rail, an upper rail for supporting a seat, a seat bracket connected to the upper rail, and a spring assembly. In one embodiment, the seat bracket is adapted to be separated from a spring structure by a stopper to increase the sliding range of the seat while maintaining spring tension.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority to and the benefit of Korean Patent Application 10-2005-0101193 filed in the Korean Intellectual Property Office on Oct. 26, 2005, the entire content of which is incorporated herein by reference. 
   FIELD OF THE INVENTION 
   The present invention relates to a seat rail, and in particular to a seat rail which is capable of improving the maneuverability and commercial value of a seat by increasing the sliding range of the seat as well as imparting the convenient maneuverability of a walk-in structure on the seat. 
   DESCRIPTION OF THE RELATED ART 
   In general, a seat rail is mounted on the floor of an interior of a vehicle to allow the seat to slide forward and backward. In certain vehicles with second and third seat rows, such as SUVs (Sports Utility Vehicles) or MPVs (Multi Purpose Vehicles), the seat rail is typically greater than 500 mm and is also combined with a spring to assist with seat movement. When one or more seats are moved to their most forward position, a passenger can more conveniently enter or exit a vehicle. Additionally, this forward position of one or more seats allows for the stowing of large packages, e.g., a large piece of luggage. 
   A conventional seat rail structure generally includes a lower rail fixed on a vehicle floor; an upper rail (which is movable backward and forward in the longitudinal direction of the vehicle on the lower rail), with a seat being mounted on the upper rail ; a spring associated with the movement of the seat; a first anchoring member for anchoring one end of the spring to the lower rail; and a second anchoring member for anchoring the other end of the spring to the upper rail. In general, a user can manipulate a lever (not shown) which allows the seat to be moved forward or backward in the vehicle so that a passenger can conveniently get in or out of the vehicle, or to provide a space for loading or storing large items. 
   When a spring is secured to the seat rail, the sliding range of the seat is restricted by the spring. Additionally, where the seat rail is short, no spring can be attached (resulting in seat movement by human force only), and where the seat rail is too long, a sagging phenomenon will occur in the spring allowing it to become disengaged. Also, current spring assisted structures are aesthetically unpleasant since the spring is projected and visible above the rail of the walk-in structure. 
   SUMMARY OF THE INVENTION 
   The present invention provides a seat rail operable to increase the sliding range of a seat, as well as improving the convenience of maneuverability of the seat through the use of a spring structure, in which the spring structure is adapted to be separable from the seat. By using the seat rail structure disclosed, a seat can be slid to an end of the lower rail because the spring is separated from the seat. Consequently, it is possible to achieve the effects of increasing the sliding range as well as the maneuverability of the seat. 
   In one aspect, the present invention is directed to a seat rail structure comprising a first lower rail which may be fixed to a floor of a vehicle; a second upper rail connected to a seat and slidingly movable along the first rail in a forward and rearward direction; a first bracket mounted on the upper rail; a second bracket releasably connected with the first bracket and supporting one end of the coil spring through a first connection hole; a third bracket mounted on the lower rail and supporting the other end of the coil spring through a second connection hole; and a fourth bracket mounted on the lower rail between the second bracket and the third bracket to act as a stopper to block the forward movement of the second bracket. In a preferred embodiment, the second bracket is not permanently fixed to either the first or second rails. 
   In one embodiment, the first bracket may be a seat bracket for supporting a seat, the second bracket may be spring bracket, and the fourth bracket may be a stopper. The spring bracket preferably supports one end of a spring and is movable in a forward and rearward direction. A fixed bracket, which may be mounted to the first lower rail, may support a second end of the spring. In one embodiment, the seat bracket may be mounted to the second upper rail and the stopper may be mounted to the lower rail. 
   In other aspects the first bracket or seat bracket comprises a first anchoring member and the fourth bracket or stopper comprises a second anchoring member. The second bracket or spring bracket may be configured to comprise at least one fixing hole operable to releasably engage the first and second anchoring member, and more preferably at least two fixing holes with one each to receive the first and second anchoring member. The first bracket or seat bracket may comprise a third anchoring member and the fourth bracket or stopper may comprise a fourth anchoring member. The second bracket or spring bracket may be configured and operable to releasably engage at least one of the third and fourth anchoring members. In another embodiment, a track cover may be provided to at least partially conceal the spring. 
   In another aspect, the present invention is directed to a seat rail structure comprising a first bracket mounted at a first location on a first rail, the first bracket supporting a first end of a spring; a stopper mounted at a second location on the first rail; a seat bracket mounted to a second rail, the second rail connected to a seat; a spring bracket supporting a second end of the spring, the spring bracket operable to engage at least one the seat bracket and the stopper, wherein the seat bracket being engaged with the stopper enables the second bracket to disengage from the seat bracket. 
   In other aspects the seat bracket comprises a first anchoring member and the stopper comprises a second anchoring member, and the spring bracket comprises at least one fixing hole operable to releasably engage the first and second anchoring member; the second bracket comprises a third anchoring member and the stopper comprises a fourth anchoring member, and the spring bracket is operable to releasably engage at least one of the third and fourth anchoring member; and a track cover. 
   In another aspect, the present invention is directed to a seat sliding structure comprising a seat bracket connected to a seat, the seat adapted to move at least forward; a first bracket connected to a rail; a spring assembly connected to the first bracket and releasably connected to the seat bracket, wherein at one time the seat moves forward with assistance of the spring assembly, and at another time moves forward without the assistance of the spring assembly. In another aspect, the spring assembly comprises a spring and a spring bracket. 
   In another aspect, the present invention is directed to a seat structure allowing movement of a seat on a rail comprising a first bracket fixed to the rail; a spring bracket; a spring having a first end attached to the first bracket and a second end attached to the spring bracket; a stopper fixed to the rail, the stopper disposed between the first bracket and the spring bracket; and a seat bracket mounted to the seat, the seat bracket engaged with the spring bracket during a first portion of forward motion of the seat and disengaged from the spring bracket during a second portion of forward motion of the seat. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a perspective view showing one embodiment of a disclosed seat rail structure according to principles of the present invention; 
       FIG. 2  is an exploded perspective view of various components of one embodiment of the disclosed seat rail structure; 
       FIG. 3  is a magnified perspective view of portion A as shown in  FIG. 1 ; 
       FIG. 4  is a cross-sectional view of the one embodiment of the disclosed seat rail structure; and 
       FIGS. 5   a  and  5   b  illustrate operating states of one embodiment of the disclosed seat rail structure. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the Figures and the following description the same reference numerals are used to designate the same or similar components. As shown in  FIG. 1 , the seat rail structure comprises a lower rail  1 , an upper rail  2 , a spring  10 , a first bracket  20 , a second bracket  30 , a third bracket  40 , a fourth bracket  50 . Also shown is portion A, described in detail below. 
   One end of spring  10  is connected to third bracket  40 , which is preferably mounted on the lower rail  1  and is adapted to support one end of spring  10  through second connection hole  42  (see  FIG. 2 ). The other end of spring  10  is connected to first bracket  20  mounted on an upper rail  2 . Lower rail  1  and upper rail  2  are adapted to allow a seat (not shown) to be moved forward and backward (with respect to the longitudinal axis of a vehicle). Spring  10  provides an elastic force that can be adapted to assist with seat movement. In the following possible embodiments, the spring preferably is at its resting state when the seat is in the most forward position, such that any tension in the spring when the seat is rearward will assist in moving the seat forward. However, in other possible embodiments, spring  10  may alternatively be arranged to bias the seat rearward. 
   In one embodiment, a seat (not shown) is preferably mounted to upper rail  2 , as is first bracket  20 . First bracket  20  is preferably configured and adapted to releasably connect to second bracket  30 . Referring additionally to  FIG. 2 , in one possible embodiment, second bracket  30  is provided with two fixing holes, first fixing hole  34  and second fixing hole  36 , as well as a connection hole  32  for connecting one end of the coil spring  10 . Additionally, first bracket  20  has a first anchoring member  22  (complimentary configured and adapted to be inserted into fixing hole  34 ) and a second anchoring member  24 , (adapted to guide and facilitate connecting first bracket  20  with second bracket  30 ). 
   As shown in  FIG. 3 , first anchoring member  22  is releasably fitted in first fixing hole  34 , and second anchoring member  24  is releasably engaged with the bottom of the second bracket  30 . In one embodiment, when a lever (not shown) is not manipulated, first bracket  20  is operable to support the second bracket  30  with first anchoring member  22  and the second anchoring member  24 . When the lever is manipulated, first bracket  20  and second bracket  30  (which are releasably connected) are jointly moved to the location where fourth bracket  50  is mounted. 
   As shown in  FIG. 2 , fourth bracket  50  has a third anchoring member  52  adapted to be releasably fitted in second fixing hole  36  in the second bracket  30 , and a fourth anchoring member  54  adapted to be releasably engaged with the top of the second bracket  30 . In particular, third anchoring member  52  and fourth anchoring member  54  are configured and adapted to connect with second bracket  30  as shown in  FIG. 5   a . Upon connecting fourth bracket  50  with second bracket  30 , the connection between first bracket  20  and second bracket  30  is released (see  FIG. 5   b ). At this time, although first bracket  20  (along with the upper rail  2 ) may continue to move toward the end of lower rail  1 , second bracket  30  is prevented from further movement by fourth bracket  50 . 
   Fourth bracket  50  is preferably mounted on lower rail  1  between second bracket  30  and third bracket  40 , thereby serving to block the forward movement of the second bracket  30 . As will be recognized by those skilled in the art, when fourth bracket  50  blocks the forward movement of the second bracket  30 , and second bracket  30  is disconnected from first bracket  20 , spring  10  maintains its natural state. 
   As shown in  FIG. 4 , a removable track cover  60  may partially cover lower rail  1  and upper rail  2 , and may also entirely cover seat rail structure, so that the seat rail structure is not outwardly exposed, thereby serving to improve the aesthetic look. 
   The operation of the inventive seat rail structure of a vehicle seat configured as described above is now described in connection with  FIGS. 5   a  and  5   b . In one embodiment, when a user manipulates a walk-in lever, a seat may be moved forward along lower rail  1  by the restoring force of the spring  10  which is in an expanded condition when the seat is in a rearward position. As the seat is drawn forward, so too are second bracket  30  and first bracket  20 , which is releasably connected with the second bracket  30 . 
   The seat is drawn forward to a point where second bracket  30  eventually arrives at the position of fourth bracket  50 , as shown in  FIG. 5   a . Upon second bracket  30  contacting and connecting with the fourth bracket  50 , i.e., through the connecting of third anchoring member  52  in second fixing hole  36  of second bracket  30 , and fourth anchoring member  54  being engaged with the top of the second bracket  30 , the connection between first bracket  20  and second bracket  30  is released. That is, as the seat is moved forward along lower rail  1 , first bracket  20  may become separated from the second bracket  30 , as shown in  FIG. 5   b  to allow the seat to advantageously continue to move forward along lower rail  1  without being limited or affected by spring  10 . Therefore, provided that sufficient length of the lower rail  1  is provided, the effective sliding range of the seat is increased. Second bracket  30  is still retained in the fixed connected state with the fourth bracket  50  by the force of the coil spring  10  since the spring is preferably not completely slack and still retains some spring tension when bracket  50  is positioned to engage bracket  30 . This also advantageously ensures that spring  10  does not become disengaged from the spring support structures due to the remaining spring tension. 
   When the seat is then moved backward or rearward (e.g., returned to its previous rearward position or state), first bracket  20  re-connects with second bracket  30  (e.g., through the reconnecting of first anchoring member  22  and first fixing hole  34 , and through second anchoring member  24  engaging with the bottom of second bracket  30 ), which in turn causes spring  10  to extend. First and second brackets  20 ,  30  are thus moved rearward in a connected state together again and spring  10  is expanded and fully retensioned. 
   If the inventive long-rail/walk-in structure described above is employed, a seat can be slid to an end of the lower rail because the coil spring is separated from the seat. Consequently, it is possible to achieve the effects of increasing the sliding range of the seat owing to the long-rail as well as improving the sliding maneuverability of the seat owing to the walk-in. 
   Although exemplary embodiments of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Any description of orientation or position provided herein is merely for convenience in describing some possible embodiments of the invention and is not considered as limitations on the invention.