Vehicle seat track assembly

A vehicle seat adjuster slide assembly. The assembly includes a formed stationary rail for attachment to the vehicle's floor structure and for carrying the remaining components of the assembly. A formed sliding rail mates with the stationary rail and adjustably retains a seat within the vehicle. The two rails are stably and slidably engaged through their respective cross sectional features, rollers and sliding bushings.

BACKGROUND OF THE INVENTION 
This invention involves a seat adjuster, more particularly, a rail and 
bearing assembly for the slide mechanism of an adjustably positioned 
vehicle seat. 
Automotive seats have long been designed for mounting on an adjuster so 
that the seat can be adjustably positioned between fore and aft locations 
to meet the occupant's convenience. The combination of the adjuster 
assembly and the seat assembly is fairly complex and can be costly to 
manufacture. Several mechanisms have been used to perform the adjuster 
function, the most common of which includes a pair of stationary or guide 
rails mounted to the vehicle that engage a pair of complementary moving or 
slide rails connected to the seat. This type of arrangement adequately 
performs the major functions required of an adjuster mechanism. First and 
foremost, when equipped with a slide lock it generally holds the seat 
securely in position within the vehicle. Second the mechanism allows the 
seat to slide forwardly and rearwardly. Additionally, the channel 
construction can be formed relatively inexpensively. 
As automobiles evolve however, new considerations come into play. More 
efficient utilization of the space within a vehicle is now required. The 
adjuster mechanism now is preferably amenable to both manual and power 
operation. A lower movement effort is preferable, but must be achieved 
without sacrificing structural stability. The cost of producing a 
mechanism has become an increasing factor in design as has the size and 
weight of the mechanism. Finally, with the development of anchoring seat 
belts to the seat assembly rather than to the vehicle itself, greater 
strength is required of the adjuster mechanism. 
A variety of efforts to design mechanisms meeting many of the above 
requirements have been made. Mechanisms have been developed using roll 
formed sheet metal for the rails as well as others using extruded metal 
rails. Numerous rail configurations and types of bearing arrangements have 
been used to provide properly functioning seat adjusters. There remains a 
need however, for an adjuster with low and consistent slide effort 
requirements, that is relatively compact in size, has high stability, is 
capable of mounting on the rocker and center tunnel of a vehicle floor and 
can be relatively inexpensively fabricated from sheet metal. 
SUMMARY OF THE INVENTION 
The present invention is a distinctive slide assembly for adjustably 
mounting a seat in a vehicle. The object of the invention is to provide a 
device that allows the seat to slide forwardly and rearwardly while 
requiring a relatively low and consistent amount of force to initiate 
movement; is structurally sturdy to stably hold the seat and adaptable to 
use in seats with an integral passenger restraint belt; is capable of both 
manual and power operation; is relatively compact; can be configured for 
mounting the seat to the rocker and center tunnel of a vehicle floor; and 
can be fabricated from sheet metal. 
A preferred embodiment of the invention includes two formed rails which 
mate together and are engaged through a unique combination of their 
respective cross sectional shapes, roller bearings, and sliding plastic 
bushings. One rail, referred to as the guide rail is stationary and is 
mounted to the vehicle. The guide rail may be fabricated from a single 
piece of metal stock, or may be made from two pieces where additional 
strength is required. The other rail referred to as the slide rail, is 
slidably coupled to the guide rail and is mounted to the vehicle seat. Two 
pairs of rails are required for each vehicle seat. The slide rail is 
contained in the vertical and lateral directions relative to the guide 
rail by its cross sectional shape which is designed to mate with the cross 
sectional shape of the guide rail. A combination of rollers and bushings 
is carried between the rails to provide a stable assembly while allowing 
the slide rail to easily and consistently slide along the guide rail in 
the longitudinal direction. This design is amenable to the integration of 
a safety belt into the seat assembly. 
In the preferred embodiment the guide rail has a unique triple U-shaped 
channel configuration. Two of the channels oppose each other from across 
the rail and provide the means for stably and slidably coupling to the 
slide rail. This is accomplished by utilizing plastic bushings between 
flanges of the slide rail and the channels of the guide rail, containing 
the slide rail in the vertical and lateral directions. The third channel 
provides a track for rollers that receive a majority of the normal load on 
the assembly thereby aiding the sliding movement of the rails. The 
bushings and rollers result in an assembly with a stable, consistent, 
longitudinal slidability along the length of the sliding portion of the 
rails. This resulting advantage occurs with the roller-bushing combination 
and the physical relationship of the rails. 
The plastic bushings are preferably made from a tough polymer that can be 
exposed to moisture and lubricants such as High Density Polyethylene. To 
provide a combination of vertical and lateral stability with bind free 
longitudinal slidability the bushings preferably have projecting 
longitudinal runners with a relatively small cross sectional guide rail 
contact area. This form of bushing can result in a shearing action of the 
runner tips during assembly of the components, removing any excessive 
material from the runners that might otherwise result in binds during 
movement of the slide rail. There are preferably two sets of runners at 
the top and bottom contact points between the rails to prevent loosening 
of the channel set by vertical loads on the seat. Additionally, to avoid 
binds the remaining runners are located to prevent the bushings from being 
squeezed by the metal guide rail. 
The preferred embodiment of the assembly is arranged for mounting the 
vehicle seat to the center tunnel and rocker of the vehicle floor. This 
type of mounting maximizes foot-room for a rear seat passenger, improves 
the aesthetic appearance of the assembly by being more readily concealed 
and minimizes the impact of seat mounting requirements on the vehicle 
underbody. 
Other objects, features and advantages of the invention will become 
apparent from the following description and the presently preferred 
embodiment thereof.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
As shown in FIG. 1, two assemblies are required to mount a vehicle seat 10 
to the floor of a vehicle 9. The seat 10, is connected to slide rails 12, 
and guide rails 11 are connected to the vehicle floor 9. 
FIG. 3 illustrates in cross section the main component parts of a slidable 
seat adjuster assembly. The component parts include the guide rail 11, 
that is formed from one piece of roll formed sheet metal. The assembly 
also includes the slide rail 12, that slidably engages the guide rail 11 
through the flanges 32 and 33, bushings 15 and 16 that are retained in 
place on the flanges, and the roller 17. This unique arrangement of the 
component parts results in an assembly that provides the required 
operational features. The large vertical dimension results in higher 
vertical load bearing capacity. The roller assures that the slide rail 
will move smoothly longitudinal to the guide rail. The bushings assure 
that the slide rail is stably contained vertically and laterally with 
respect to the guide rail. The arrangement of mating rails with a 
combination of bushings and rollers in the assembly may be constructed in 
other similar spacial relationships to obtain analogous results. 
In the preferred embodiment the guide rail 11 is mounted to the floor of a 
vehicle 9, as shown in FIG. 1, on or near the center tunnel 7 and the 
rocker 6. Therefore, the guide rail is stationary in relation to the 
vehicle. The guide rail is mounted to the vehicle by connecting the guide 
base wall 41, which is the vertical portion of guide rail 11, to the 
vehicle through fastening means that may include accessory brackets to 
spatially position the guide rail 11 in a location determined by the seat 
design, while providing connection to the contoured surface of the 
vehicle's floor. 
Preferably, along the top and bottom of the guide base wall 41 are three 
U-shaped channels 42, 43 and 44, that together with the guide base wall 41 
constitute the one piece guide rail 11. The top U-shaped channel 42 
extends longitudinally along the top of the guide base wall 41, and opens 
downwardly. The bottom U-shaped channel 43, adjacent to the bottom of the 
guide base wall 41, extends longitudinally along the bottom of the guide 
base wall 41 and opens upwardly. The second bottom channel 44 is located 
adjacent to the first bottom channel 43, further from the guide base wall 
41 than the first bottom channel 43. The second bottom channel 44 opens 
upwardly and extends longitudinally substantially along the length of the 
guide rail 11, parallel to the first bottom channel 43. 
The guide rail is preferably fabricated from sheet metal using a roll 
forming process. The configuration of the guide rail is the aspect 
important to proper operation of the adjuster assembly. Therefore, the 
forming process and composition of the rail are not critical and an 
extruded rail or otherwise properly formed rail is acceptable, provided 
the strength of the finished product approximates or surpasses that of 
roll formed sheet metal. 
The slide rail 12 is connected to a vehicle seat shown in FIG. 1 and 
designated as 10, at the slide face wall 31, to adjustably position the 
seat within the vehicle. The slide rail 12 includes a slide face wall 31, 
side walls 34 and 35, and terminal flanges 32 and 33. The slide rail 12 is 
slidably, engageably connected to the guide rail 11 by the flanges 32 and 
33, with bushings 15 and 16 disposed between the rails. The two U-shaped 
channels 42 and 43, of the guide rail 11, form opposing receptive cavities 
in which the terminal flanges 32 and 33 of the slide rail 12 are located. 
The terminal flanges, and thereby the slide rail, are stably contained 
within the channels both vertically and laterally by the bushings. The 
roller 17 and the bushings 15 and 16 further enable the integral flanges 
of the slide rail to consistently slide longitudinally within the channels 
along the length of the slide portion of the elongated rails. As with the 
guide rail, the slide rail in the preferred embodiment is fabricated from 
roll formed sheet metal, although that aspect is not critical to proper 
operation of the assembly. 
The bushings 15 and 16, are fixedly retained in place along the flanges 32 
and 33, and slide within the channels 42 and 43. In the preferred 
embodiment, the bushings are held in place on the slide rail flanges by 
providing slots in the flanges and by providing a cavity in the bushing 
for receiving the flange, with webs in the cavity that mate with the 
flange slots. Preferably, at the top and bottom contact points between the 
slide rail assembly and the guide rail channels, the bushings have paired 
projections forming runners identified as 54 through 57. In the preferred 
embodiment, there are two sets of vertical runner pairs disposed along 
each bushing. Alternatively, one pair of runners may be provided 
substantially along the length of the bushing. Runners 54 through 57 
contain the slide rail in the vertical direction. Additionally, the 
runners identified as 50 through 53 contain the slide rail in the lateral 
direction. The lateral runners are also preferably provided in a set of 
two on each side of a bushing. Alternatively, one runner may be provided 
substantially along each side of a bushing. 
An advantage of using runners with a relatively small cross-sectional 
contact area is that a stable engagement with the guide rail 11 results 
without binding during sliding movement. An unapparent means of arriving 
at this result occurs during assembly of the component parts of the seat 
adjuster. In assembly, the bushings 15 and 16 are secured on a formed 
slide rail 12, then the slide rail is inserted into the formed guide rail 
11 from an end. As the slide rail is inserted, if the tips of runners 
50-57 extend beyond the cross section of the channel openings defined by 
the inside edge of the U-shaped channels 42 and 43, a shearing action 
results and the runner tips will be trimmed by the leading edge of the 
guide rail channel. The trimming of any runner projecting beyond the space 
allowed by the channel openings provides an increased stable slidable 
contact between the slide rail 12 and the guide rail 11, free of binds 
that previously were associated with assemblies using plastic bushings. In 
the preferred embodiment the bushings are formed from high density 
polyethylene, although any of a number of well known, non-corrosive, 
anti-friction bearing materials may be used. 
The roller 17 is contained within the second bottom U-shaped channel 44. 
During normal conditions with weight on the vehicle seat, the roller bears 
a majority of the vertical force exerted on the bearing surfaces of the 
assembly. The physical arrangement of the component parts of the assembly 
with the roller situated as described, and contacting the bottom side wall 
35 of the slide rail 12, provides the sliding ease required and allows for 
both manual and power operation of the basic seat adjuster assembly. 
Referring now to FIG. 4, an alternative embodiment of the invention is 
shown. Although substantially the same as the embodiment described in FIG. 
3, the guide rail is assembled from two separate components. The inner 
formed section 61, includes a vertical base wall 41' and upper and lower 
integrally formed U-shaped channels 42' and 43' resulting generally in a 
C-shaped configuration. The upper and lower channels 42' and 43' serve the 
same functions as described in relation to FIG. 3, concerning the top 
U-shaped channel 42 and the first bottom U-shaped channel 43, providing an 
engagement mechanism for the slide rail. The outer formed section 71, 
includes a vertical base wall 73, a top bend forming a longitudinal flange 
74 substantially perpendicular to the base wall 73, and a bottom L-shaped 
channel portion 75 extending longitudinally and opening upwardly. The 
outer formed section 71, is designed to allow the inner formed section 61, 
to nest within its bounded area with the outside surface of the inner 
section's base wall abutting the inner surface of the outer section's base 
wall. Upon assembly, the bottom L-shaped channel 75 is designed to 
cooperate with the lower formed channel 43' of the C-shaped inner section 
to create a second bottom U-shaped channel 44' adjacent to the first 
channel 43' created by the C-shaped section, equivalent to the second 
bottom U-shaped channel 44 described in relation to FIG. 3, creating a 
track for the roller 17'. 
The two-piece guide rail construction described is designed to provide 
additional strength over the one-piece embodiment without using 
excessively thick stock material when desired. The two formed sections of 
the guide rail 61 and 71, are preferably welded or fastened together for 
increased rigidity. The unique arrangement of mating rails, plastic 
bushings and rollers that exists with the one-piece guide rail embodiment 
shown in FIG. 3, also results from the two-piece guide rail embodiment as 
shown in FIG. 4. 
FIG. 2 illustrates the longitudinal nature of the seat adjuster assembly. 
The depiction is a side elevation of the basic aspects of a seat adjuster 
mechanism. The guide rail 11, is shown with the top U-shaped channel 42, 
and the bottom U-shaped channel 44, extending along the rail. Bent tabs 45 
and 46 are formed in the channel 44. The tabs act as stops for the 
movement of the rollers 17 and 18. An appropriate number of rollers is 
required to provide adequate slidability of the slide rail as is a means 
of ensuring they remain disposed along the rail. Two rollers 17 and 18 are 
shown disposed in the channel 44, separated by a spacer 19 to maintain a 
relative minimum positioning. This arrangement provides the required 
slidability. One of the tabs 45 or 46 may be pre-bent before the 
components are assembled. After the Rollers 17 and 18 and the spacer 19 
are inserted into the channel 44, and the slide rail 12, and bushings are 
in place, the second tab may be bent. 
The bushings required for stability are shown in FIG. 2 as 13, 14, 15 and 
16. They are distributed on the flanges of the slide rail 12, to provide a 
sound engagement with the guide rail 11. The bushings are preferably held 
in place on the slide rail flanges while allowed to slide within the 
channels of the guide rail. 
The holes represented by 91 in the face wall of slide rail 12, are for the 
purpose of illustrating a fastening means for attaching the slide rail to 
a vehicle seat 10. One method of attaching the slide rail to the seat is 
by pressing or welding a stud into the hole 91 for attachment to the seat 
structure. Similarly the holes represented by 93 in the guide rail 11 are 
for illustrative purposes to show that a means for attaching the guide 
rail 11 to a vehicle's floor structure 9 is required. 
While this invention has been described in terms of preferred embodiments 
thereof, it will be appreciated that other forms could readily be adapted 
by one skilled in the art. Accordingly, the scope of this invention is to 
be considered limited only by the following claims.