WO1997004986A1

WO1997004986A1 - Track for seat belt restraint system

Info

Publication number: WO1997004986A1
Application number: PCT/US1996/012505
Authority: WO
Inventors: Bradley M. Glance
Original assignee: Concept Analysis Corporation
Priority date: 1995-08-01
Filing date: 1996-07-31
Publication date: 1997-02-13
Also published as: AU6684796A

Abstract

A restraint seat track comprises a pair of laterally spaced track assemblies, each of which include telescoping inner (10, 42) and outer (11, 41) tracks, the outer track having a generally C-shaped cross section and the inner track having a C (47) or O(10)-shaped cross section, with the tracks being assembled to form a closed rectangular section, and mounted vertically in the vehicle. The restraint track carries all occupant lap and shoulder belt loads during a vehicle crash. A unique closed end design is utilized at the rear-most end of the track to prevent inner track collapse (44) and outer track opening (45), thereby providing anti-peel of the track assembly during a vehicle crash and resisting subsequent bending loads created by the seat mounted shoulder belt. A unique full loop or C-clamp outer track reinforcement (46) is utilized to provide efficient outer track local stiffness at high stress locations without full length track reinforcement. Both power, extruded magnesium, and roll formed metal manual tracks are employed.

Description

TRACK FOR SEAT BELT RESTRAINT SYSTEM

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation application of co-pending United States Patent Application Serial No. 60/001,742, entitled RESTRAINT SEAT TRACK FOR AUTOMOTIVE INTEGRATED SEAT BELT RESTRAINT SEAT SYSTEM and filed on August 1, 1995, by Bradley M. Glance, the disclosure of which is incorporated here by reference.

BACKGROUND OF THE INVENTION Most automotive seat adjusters work on the principle of linear seat tracks that slide forward and backward relative to one another. One side of the track is fixed to the vehicle and the other fixed to the seat. The tracks are either horizontally or vertically mounted with respect to each other. Horizontally mounted devices generally utilize tracks with rectangular cross sections, wherein the wider side of the track is oriented horizontally and mounting bolts extend vertically through the tracks and are secured to the vehicle and seat base respectively. Most track systems in the North American market are horizontal.

Tracks can be power or manually driven. A power driver involves the use of a motor, gear drive, and lead screw or gear rack. A manual track is adjusted by the occupant and is spring loaded to aid in track movement. Usually, a set of pawl teeth latches and matching tack hole set are employed to lock the manual tracks. The power track is locked by virtue of the drive screw mechanism and has the advantage of constant engagement.

A so-called "restraint track" is a track that is capable of carrying all of the occupant seat belt loads through the track without catastrophic failure during a 35 mph vehicle collision.

At the present time, the only automobiles that have a seat integrated restraint (SIR) seat and restraint tracks are two luxury vehicles. They both use vertical track sections. All other production vehicle tracks are relatively weak and cannot withstand the combined load of a lap and shoulder belt loop load (i.e., approximately 8,400 pounds combined belt pull). SUMMARY OF THR INVENTION In accordance with the present invention an improvement in current track design provides an efficient means to achieve a cost effective yet strong seat integrated restraint track. The present invention introduces improved design concepts that create high strength tracks without significant increase in track cost or mass.

Most often an outboard SIR track fails in "peel". This occurs when the inner and outer track are peeled apart starting from the rear-most end.

The present invention includes an anti-peel end cap to resist inner and outer track separation.

A secondary mid (full or partial) loop clamp on the outer track further restrains track separation.

A plug is incoφorated in the rear end of the inner track section to prevent the inner track section from collapsing under load. The plug is welded, bonded, secured with an interference fit, or secured with a mechanical attachment.

The present invention also utilizes unique track cross sections that are naturally strong in vertical bending and keep the inner and outer track working as a structural unit. There is good overlap and entrapment between the outer and inner track.

The present invention includes two basic track sections, an extruded shape for a power track and a roll form shape for a manual track. The power track utilizes a plastic guide and the manual track utilizes a roller bearing to enable inner and outer track relative movement with low friction.

The present invention is an improvement over current seat adjuster/track systems in that it employs, among other features: 1) Anti-peel end cap or loop reinforcement, on outer track to prevent track opening.

2) Anti-peel mid clamp or loop reinforcement.

3) A unique power track section.

4) Both sections are capable of vertical or horizontal mounting. 5) Addition of a plug to close inner track section and prevent inner track collapse.

6) A unique manual track section.

The resulting tracks of this invention are mass competitive to the current, weaker automotive tracks. In the present invention, a load carrying restraint seat track system comprises two generally C-section inner and outer tracks, with good over-lap, that are assembled to form a rectangular vertical, strategically placed closed-off reinforcement at the end and mid position of the track. The present invention represents a significant improvement in automotive seat tracks, because it permits the creation of uncomplicated and light weight track sections that are strong enough to carry seat belt loads. In one aspect of the present invention, the track comprises an extruded magnesium power track that has a lower mass than a conventional metal track, yet is stronger. Through utilization of the magnesium material in the full cross sectional length, and reinforcing only at high stress locations, the magnesium material utilization is minimized to create an efficient restraint track system.

Since the upper shoulder belt attachment is located on the outboard side of the seat, the primary occupant shoulder belt is reacted through the outboard track. The resulting track design requirement for inboard and outboard tracks are different, and the inboard track can be lower strength and lower mass than the outboard. To increase structural load-carrying capability of the outboard track without adding full length cross section reinforcement, rear close-offs, inner track reinforcements, additional attachment, and floor support have been designed in the track system.

A number of variations in the design, construction, and material usage are possible. The extruded track section can be extruded from aluminum, magnesium, or other appropriate high strength material. The roll formed track section can be roll formed of steel, aluminum, or other material having comparable characteristics.

Preferably, a 2.2 to 3 mm (millimeter) thick roll formed high strength steel or aluminum material is utilized for the manual track section. The outer track section has an open, generally C-shaped cross section, and the inner section preferably has a closed box cross-sectional shape, although an open C-section inner track is also feasible.

Preferably, the extruded magnesium track consists of two open C-shaped cross sections that vary in thickness from 3 to 6 mm, as required by specific design applications. These and other features of the present invention are apparent from the attached drawings and detailed description of the preferred embodiments set forth below. DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a restraint seat system with a pair of restraint manual tracks.

FIG. 2 is a side view of a power restraint track assembly. FIGS. 3A-3E are cross sections taken along lines 3A-3A through 3E-3E of

FIG. 2.

FIGS. 4A and 4B are cross sectional views of an assembled manual track section, with FIG. 4B showing a reinforcing clamp mounted on the outer track.

DESCRIPTION OF PREFERRED EMBODIMENTS

Manual Track:

An exploded view of a restraint seat system 30 is shown in FIG. 1. For reference, the fabric trim and foam cushion are shown at 1. Outside and inside seat plastic trim covers are shown at 2a and 2b. The seat back frame is 3, and the seat cushion frame 4. The head rest frame cover and mounting is shown at 5.

The seat back frame 3 is structural, comprising a rigid vertical beam 32 contained in a hollow channel in an outboard side of the seat back. A high mount seat belt retractor 6 is mounted to the upper end 34 of the beam. The lower end of the belt 36 includes a mounting fixture 38, which is mounted to the seat at fastener opening 40 and moves with the seat when the track is adjusted.

The belt loads are transmitted through an inboard pivot bracket 8 and outboard recliner 9 to inboard and outboard inner seat tracks 10, to which the pivot bracket and recliner are mounted. The upper shoulder belt load is transferred directly through the seat back beam 32 to recliner 9 (to which the beam is mounted) and then to the inner manual track 10. The outboard outer track 11 has attachment openings 12 in three locations for mounting to the vehicle structure. Outer track 11 can be employed on both sides of the seat, i.e., inboard and outboard. Preferably the track is mounted to the vehicle sill or rocker structure on the outboard side and to the tunnel or floor structure on the inboard side. A cross tube 13 and brackets incoφorated therein are employed to mount the seat cushion frame to the tracks. The seat construction is the same for the manual and powered seat tracks.

The manual track desirably employs a roll formed track formed of 2.2-3.0 mm high strength steel or aluminum. The metal track sections in the manual track have a unique end cap or clamp 14a and a mid-clamp 14b to close-off the track at the rear and intermediate positions, respectively. These clamps provide anti-peel of the inner and outer track. The clamps can have a C-section open shape as shown by clamp 14a in FIG. 4B or they can be loops, which means a full O-section closed shape as shown by element 14a' shown in phantom in FIG. 4B.

The manual track assembly cross section is shown in FIGS. 4A and 4B. The outer track 11 has an open C-shaped cross section with oppositely inclined bearing surfaces 64 and 65 on the top and bottom sides. The inner track 10 desirably is a closed box member, as illustrated in FIGS. 4A and 4B, with an outwardly extending vertical section 69 fitting in the opening or slot 82 in the inner side of the C-shaped outer track. The upper and lower surfaces of inner track 10 have inclined bearing surfaces 84 and 86 that are spaced from surfaces 64 and 65.

Roller bearings 63 are located on the inclined bearing surfaces, between the inner and outer tracks, to provide relative sliding movement between the two track sections with low friction, while providing lateral and vertical support. The local track outer clamp

14a is shown in FIG.4B. This could alternatively be a loop by the addition of phantom section 14a' as discussed above.

Attachment stud 68 attaches from the outer track to the fixed vehicle structure 50 and attachment stud 67 attaches the inner track to the seat bracket 8 (or recliner 9 or seat or seat frame 13). The track is shown as mounted vertically. Because of the unique orientation of the angled roller bearings, however, the track could also be mounted horizontally.

A pivot-mounted latching pawl 18, mounted to the inner track 10, engages a set of holes in outer track bracket 19 to provide track lock. Occupant handle lever 20 releases the latch pawl for track adjustment. Return springs 21 aid in positive track locking.

Spring 71, attached between outer track 10 and a bracket 13a that is attached to the vehicle, urges the seat forwardly when the latch is released.

Also shown for reference in FIG. 1 are inboard floor risers 15a and 15b and seat suspension members 17a and 17b that are attached in openings in the seat and back portions of the seat mechanism. Extruded Power Track:

FIGS. 2 and 3 show a side view and various sectional views of an extruded power track assembly 39 that can be used instead of the manual track assembly in the seat of

FIG. 1. An outer track 41 has a constant C-shaped cross section with thickness increased at the open ends of the track and along the edges of the open side of the track to improve section opemng stiffness. An inner track 42 is a smaller constant C-shaped cross section that fits into the outer track. An extended portion 47 fits through the opening or slot 37 in the inner side of outer track 41. The inner track section 42 is also varied in cross section thickness locally to increase strength at high stress locations. Variation in wall thickness is easily obtainable in the extrusion process. The powered track is driven in a conventional manner by a motor driven drive screw or the like, shown schematically as element 35 in FIG.

2. The drive screw holds the seat in place when the motor is deactivated.

Preferably, both inner and outer tracks 41 and 42 of the power track 42 and 41 are extruded magnesium approximately 3 mm thick, with local increased thicknesses of 4 to 6 mm. The outboard track structural strength requirements are higher than the inboard track because of shoulder belt mounting on the outboard side. The outboard track can be designed thicker than the inboard track to accomplish these load requirements.

An inner plastic glide 43 is utilized between the inner and outer track to aid in relative sliding movement between the inner and outer track. The outer track is mounted in a fixed position to the vehicle 50 by attachment 48 and the inner track is mounted to the moving seat 4 (or seat support cross member 13) by attachment 49. All lap and shoulder belt vehicle crash loads are reacted through the restraint track assembly.

To prevent collapse of the inner track, the rear-most end of the inner track is closed-off, which means that the end is a solid section, which can be accomplished with an end plug 44.

A mid or intermediate loop or clamp 46 can be utilized to prevent the outer track from opening. An end cap 45 (FIG. 2) is utilized at the rear-most track end to prevent the outer track from opening. End cap 45 encircles or clamps on the side of the outer track adjacent the end in the same manner as the loop 46 in FIG. 3D. The cross sectional shapes of inner track 42 and outer track 41 are designed to permit attachment bolt mounting and good overlap and anti-peel separation of the two sections relative to one another. In FIGS. 3A-3E, there are five cross sections taken through the track assembly. The cross section of FIG. 3A is cut through the assembled track front, showing the outer track, inner track, plastic glide, and fasteners to the vehicle and seat respectively.

The cross section of FIG. 3B is cut through the track outer by itself. The cross section of FIG. 3C is cut through the track inner by itself. The cross section of FIG. 3D is cut through a mid-loop. The same section exists at the track end through the end cap. Shown is the outer loop or clamp, utilized to prevent the outer track from opening. The inner, outer, and plastic glide are also shown in FIG. 3D. The cross section of FIG. 3E is cut at the rear end of the inner track shown with end plug 44. While the foregoing is exemplary ot the preferred practice of the present invention, other arrangements and details of construction of the present invention are possible without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

I Claim:

1. A longitudinally adjustable seat track for mounting a vehicle seat in a vehicle comprising: a pair of longitudinally oriented, laterally spaced telescoping track assemblies, each track assembly comprising an inner track mounted for axial movement in an outer track, the outer track having top and bottom walls and inner and outer sidewalls surrounding an open interior, the inner sidewall having an elongated opening therein that extends vertically only for a portion of the height of the inner sidewall, leaving upper and lower inner sidewall flanges adjacent the opening, the inner track comprising a hollow interior and an exterior that conforms with an interior configuration of the outer track, the inner track having a sidewall that spans the opening in the outer track sidewall and includes upper and lower portions that extend beyond the opening in the sidewall and are positioned opposite to the upper and lower flanges in the outer track sidewall, low friction means positioned between the inner and outer tracks for reducing sliding friction between the inner and outer tracks; means for attaching the outer tracks to a vehicle; means for attaching the inner tracks to a vehicle seat; and reinforcement means at least partially encircling a rear end of the outer track so as to restrain the rear end from opening and the inner and outer tracks from separating under stress caused by a vehicle collision.

2. Apparatus as in claim 1 wherein the tracks and low friction means are shaped and fit together so as to constrain the inner track to axial movement with respect to the outer track.

3. Apparatus as in claim 1 wherein the top and bottom walls of the inner and outer tracks comprise inwardly and outwardly inclined bearing surfaces, the low friction means thus restraining the inner track from lateral as well as vertical movement with respect to the outer track.

4. Apparatus as in claim 3 wherein the low friction means comprises roller bearings that engage each of the inclined bearing surfaces.

5. Apparatus as in claim 1 wherein the low friction means provides a low friction surface between opposed inner and outer and upper and lower surfaces of the walls of the inner and outer tracks.

6. Apparatus according to claim 1 wherein the sidewalls of the tracks are vertically oriented, the outer track being fastened to the vehicle and the inner track being fastened to the seat, the vertical height of the track assembly being greater than the width of the track assembly.

7. Apparatus according to claim 1 wherein the edges of the upper and lower flanges, adjacent the opening in the outer track, are reinforced.

8. Apparatus according to claim 7 wherein the outer track has a relatively uniform wall thickness, with the exception that the reinforcement in the flanges comprises an increased wall thickness of the flanges relative to the wall thickness of the rest of the outer track.

9. Apparatus according to claim 3 wherein the top and bottom walls of the inner and outer tracks are substantially horizontal and the sidewalls are substantially vertical, and the low friction means comprises a plastic glide positioned between top and bottom walls and inner and outer sidewalls of the inner and outer tracks.

10. Apparatus according to claim 1 wherein the portion of the inner track sidewall that spans the slot in the outer track extends outwardly through the slot and provides a seat mounting surface at an outer side of the outer track.

11. A longitudinally adjustable seat track for mounting a vehicle seat in a vehicle comprising a pair of longitudinally oriented, laterally spaced telescoping track assemblies, each track assembly comprising: a C-shaped outer track having top and bottom walls and a pair of sidewalls, one of the sidewalls having an elongated slot therein, said one sidewall having upper and lower flange portions positioned on opposite sides of the slot; an inner track that slidably fits in the outer track, the inner track being at least partially hollow and including top and bottom walls adjacent the top and bottom walls of the outer track and a pair of spaced sidewalls positioned adjacent the outer track sidewalls, the sidewall of the inner track that is adjacent the slotted outer track sidewall extending across the slot and having upper and lower ends positioned opposite the upper and lower flanges of the outer track sidewall, such that the upper and lower flanges restrain separation of the inner track from the outer track by lateral movement of the inner track through the slot in the outer track sidewall; low friction means positioned between the outer and inner tracks for reducing sliding friction between the tracks; a reinforcing member positioned on a rear end of the outer track, the reinforcing member at least partially enclosing the top and bottom walls and sidewalls of the outer section so as to restrain the slot in the outer section from spreading apart to permit separation of the inner and outer tracks upon receipt of stresses exerted on the seat track resulting from a vehicle collision; and an intermediate reinforcing member at least partially encircling the outer track at a position part way between opposite ends thereof, the intermediate reinforcing member restraining separation of the outer and inner tracks through the slot during a vehicle crash.

12. Apparatus as in claim 11 and further comprising an internal reinforcement member that fits inside at least a portion of the hollow inner track section so as to restrain the inner track section from collapsing and being pulled out of the outer track through the slot upon vehicle impact during a crash.

13. Apparatus as in claim 12 wherein the internal reinforcement member comprises a solid plug that fits in the rearmost end of the inner track.

14. Apparatus according to claim 11 wherein the intermediate reinforcing member encircles the entire outer track and is sized and positioned such that a portion of the reinforcing member extending across the slot does not impair longitudinal sliding movement of the seat mounted on the inner track through a full range of movement. 1 t

15. Apparatus according to claim 11 wherein the inner and outer tracks are formed of roll formed metal, and the low friction means comprises roller bearings positioned between the inner and outer tracks.

16. Apparatus as in claim 15 wherein thε inner track is a tubular box beam enclosed on all sides.

17. Apparatus as in claim 11 wherein the seat track mechanism further comprises adjustment means for adjusting the relative axial positions of the inner track and outer track and releasably holding the inner and outer tracks in desired axial positions relative to each other.

18. Apparatus as in claim 17 wherein the adjustment mechanism is a power drive mechanism wherein an electrically driven motor engages a gear mechanism interconnecting the inner and outer tracks and moves the inner track relative to the outer track.

19. Apparatus as in claim 17 wherein the adjustment mechanism is a manual mechanism wherein a mechanical latch interconnecting the inner and outer track is mechanically engaged to hold the tracks in a desired axial position and is disengaged to permit relative axial movement of the inner and outer tracks.

20. Apparatus as in claim 11 wherein the tracks are formed from extruded metal, with open ends of the outer track and the edges of the slots in the outer section being thicker than the other walls of the outer track.

21. Apparatus as in claim 20 wherein the tracks are formed of magnesium and have a normal wall thickness of 3 to 6 millimeters, with the wall thickness being greater adjacent the slot.

22. Apparatus as in claim 17 wherein the tracks are formed of roll formed steel or aluminum, the low friction means comprises rolling bearings, and the adjustment means is a mechanical adjustment mechanism.

23. Apparatus as in claim 17 wherein the tracks are formed of extruded magnesium, the low friction means comprises a low friction plastic material positioned between the inner and outer tracks, and the adjustment mechanism is power driven adjustment mechanism.

24. A power restraint seat track for a vehicle seat comprising telescoping outer and inner tracks formed from extruded metal, with the outer and inner tracks having C-shaped cross sections, with the open sides of the C-shapes facing opposite to one another, the inner section sliding relative to the outer section, a plastic bearing guide material positioned between the inner and outer tracks providing a low coefficient of friction for sliding movement, a lead screw and motor drive mechanism drivingly interconnecting the tracks to propel the inner track relative to the outer track, the outer track being attached to the vehicle structure and the inner track being attached to the seat the seat track assembly being sufficiently rigid structurally to carry all occupant seat belt loads, including lap and shoulder belt.

25. A manual restraint seat track section comprising telescoping inner and outer tracks formed from a roll formed metal, with a generally C-shaped outer track cross section and a generally C or O-shaped inner track cross section, the open side of the inner and outer track sections being orientated opposite to oi another to form an assembled closed, strong section sufficient to create a structural restraint track system, a set of roller or ball bearings being positioned between the inner and outer tracks to reduce sliding friction, the outer track being mounted to the vehicle structure and the inner track being mounted to the sliding seat, all occupant belt loads during a vehicle crash being transmitted through the seat to the inner track and then to the outer track and are thereafter resisted by vehicle structure outer track mounts a spring loaded pawl and sector latch mechanism actuatable by a manually operable handle providing manual track adjustment by the occupant.

26. A seat track as in Claim 24 and 25 where both tracks have a generally rectangular cross section and are orientated vertically such that a longer side is mounted vertically in the vehicle, thereby providing greater bending resistance in the vertical direction and efficient shoulder belt displacement resistance.

27. A seat track as in Claim 24 where the inner and outer tracks comprise an extruded magnesium product.

28. A seat track as in Claims 24 and 25 where the inner and outer C-shaped tracks are oriented facing each other in opposite directions so as to create an assembled close- section with good torsional strength.

29. A seat track as in Claim 24 and 25 where the attachment to the seat and vehicle are in the horizontal direction on the track center to allow the opposing attachment bolt loads to pass one another on the inside of the assembled track section.

30. A seat track as in Claim 24 where the extruded cross section is increased in thickness locally at open ends and attachment areas to improve structural restraint performance.

31. A seat track as in Claims 24 and 25 where the rear-most end of the inner track is closed off to improve structural stiffness to resist inner track collapse.

32. A seat track, as in Claims 24 and 25 where the rear-most end of the outer track is closed-off to improve structural stiffness to resist outer track opening.

33. A seat track as in Claims 24 and 25 where the rear-most end of the outer track is closed-off by means of an end cap or end loop to resist track peel.

34. A seat track as in Claims 24 and 25 where a third cross sectional shape of a full loop fits over the outer track to prevent outer track opening and inner track from peeling apart from outer track.

35. A seat track as in Claims 24 and 25 where a generally c-shape clamp is utilized to fit over the outer track to prevent track peel.

36. A seat track as in Claims 24 and 25 where the basic cross section can be rotated 90 degrees such that the track can be utilized either as a vertical or horizontal mounted track by virtue of the design and position of the guide and or bearing system.

37. A restraint seat track as in Claims 24 and 25 where the structural resistance requirements of the outboard track pair is greater than the inboard track thereby permitting use of a thicker and stronger outboard track section.

38. A seat track as in Claims 24 and 25 where the outboard track is vertical and mounted to the vehicle sill (floor side structure).

39. A seat track as in Claims 24 and 25 where the inboard track is horizontal and mounted to the vehicle floor structure.

40. A seat track as in Claim 25 where the roll formed track is preferably a high strength steel or aluminum.

41. A seat track as in Claim 25 where a roller bearing is utilized for manual steel tracks is preferably steel and preferably nylon or suitable plastic roller bearings are utilized for the aluminum track to prevent excessive track wear.

42. A seat track as in Claim 24 or 25 and further comprising a set of vehicle track attachments that provide two attachments at both ends, for the inboard track to the vehicle and three or more attachments from the outboard track to the vehicle structure. The outboard track attachments are located preferably at both ends and mid-position opposite the of seat recliner front attachment to improve track structure and lower track mass. More than three attachments or full floor support is also advantageous.

43. A seat track as in claim 24 or 25 wherein the general cross sectional shape and design of tracks is as shown in the application cross section drawings.