AU610859B2

AU610859B2 - Slide rail device for vehicle seat

Info

Publication number: AU610859B2
Application number: AU12511/88A
Authority: AU
Inventors: Masatatsu Kanai; Muneharu Urai
Original assignee: Tachi S Co Ltd
Current assignee: Tachi S Co Ltd
Priority date: 1988-03-01
Filing date: 1988-03-01
Publication date: 1991-05-30
Anticipated expiration: 2008-03-01
Also published as: AU1251188A

Description

'ij N E DOLLA ONES EINUE Ir i

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION Form

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: SPriority: SRelated Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: TACHI-S CO., LTD.

2-12, MATSUBARACHO 3-CHOME

AKISHIMA-SHI

TOKYO

JAPAN

Actual Inventor: Address for Service: CLEMENT HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

Complete Specification for the invention entitled: SLIDE RAIL DEVICE FOR VEHICLE SEAT The following statement is a full description of this invention including the best method of performing it known to me:-

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lA- SLIDE RAIL DEVICE FOR VEHICLE SEAT BACKGROUND OF THE INVENTION 0 o 0 0 0 o 0 0 0 5 0 1. Field of the Invention o 0 0 nr o The present invention relates to a slide rail device used in a vehicle seat, an automotive seat or the like, which is adapted to adjust the forward and rearward positions of the seat, and in particular, Srelates to a slide rail device of the type having Sa seat belt provided on its upper rail and designed ao to avoid the separation of upper rail from lower rail in a sudden deceleration due to a collision 15 accident or the like.

0 0 2. Description of the Prior Art Heitherto, there have been known various kinds of slide rail devices for vehicle seats, and among them a type of the device has been in use which has a seat belt anchored thereto in order to disperse a pulling force exerted on the seat belt to the floor of the vehicle and further so desinged to prevent the disengagement of its upper rail from its lower -2rail for safety purpose against a sudden deceleration when a collision accident or the like occurs.

In this sort of slide rail device, one end portion of the seat belt is fixedly connected to the upper rail in most cases. The seat belt restrains an o occupant who sits on the seat provided above the upper 0 ~rail, and the restraint fo r ce of the seat belt is O 0 0 0 supported on the upper rail.

0 Various examples of such slide rail device are known, for example, from the Japanese Utility Model 0000 Publication No. 57-24594, or the U.S. Patent No.

O 0 4204658.

o Those prior art devices are basically similar o 0 to such construction as shown in Fig. 1 of the accompanying drawings. Hereinafter, the structural 00advantages and disadvantages of the prior art will be discussed with reference to the model in Fig. 1.

Namely in the prior a r t, a plurality of equidistant apertures (102) are formed in the shoulder portion (130) of an upper rail (114) and a plurality of engagement teeth (104) which are equidistant from one another corresponding to each of the aipertures (102), ate formed at the end of an upper curved flange portion (128) of a lower rail (112). The engagement teeth (104) are respectively disposed above each of i i I3 1 the apertures (102). With this structure, in the case of a sudden deceleration due to a collision accident, a pulling force is applied to the upper rail (114) (See Fig. 2) which tends to raise the upper rail (114), anrd thus, as the upper raill (114) is o moved upwardly, the teeth (104) of the lower rail 0 o 0 o (112) are inserted into and engaged in the respective 0 0 0 apertures (102) of the upper rail (114), as shown o 0s 0 in Fig. 2. Accordingly, the upper rail (114) is 0 prevented from its separation from the lower rail oo (112).

However, the pulling force being applied u os is, in fact, oriented obliquely in a direction inwardly of the slide rail device, as shown in Fig. 2.

Such pulling force is in turn exerted upon the 0 upper curved flange portion (128) because of the full engagement of the teeth (104) in the respective apertures (102). Then, the upper curved flange portion (128), which is formed in a cantilever fashion, is easily bent upwards relative to a base point with the result that the teeth (102) are raised at the same time, as illustrated in the phantom line in Fig. 2. This is, in the dynamic sense, attributed to a bending moment caused by the pulling force and in particular, a greater amount of such r 4 bending moment is caused in the series of the teeth (102) disposed outwardly of the device (i.e.

the one disposed on the left side as viewed in Fig. As a result, there is a great likelihood 5 of those outwardly disposed series of teeth (102) a 0 being disengaged out of their corresponding apertures 0 a aa o 0 0 (102) one by one. Thus, according to the noted oa prior art, it is not possible to prevent the upper o rail (114) from completely separating from the lower rail (112) o a Of course, the foregoing problem can be solved y by forming the upper and lower rails of thicker material to increase their rigidity against na deformation. But, such formation of the upper and lower rails results in greater dimensions oo of the slide device as a whole, requiring additional room under the seat, and also results in increased weight of the device, which is not economical in costs for assemblage thereof and disadvantageous in providing a light weight seat. Further, in contrast to the above-mentioned prior art, there has been such aslide rail device as disclosed in the Japanese Laid-Open Utility Model Publication No. 49-106021. According to this other ii. i ~1~1~ 5 prior art, the upper rail is at its lower portion formed with a substantially U-shaped curved portion and the lower rail is also formed with a likewise curved portion in such a manner that the curved 5 portion of the upper rail encloses that of the lower 0 0 rail. Nevertheless, it is quite possible for the o Supper rail to be separated from the lower one, because o owhen a great upward pulling force is exerted on the 00 o upper rail, the curved portion of the upper rail is easily opened, resulting in the upper rail ob slipping off from the curved portion of the lower rail 0o and becoming separated therefrom.

SUMMARY OF THE INVENTION SUMMARY OF THE INVENTION 00000 0 0 In view of the above-mentioned drawbacks of the prior art, it is therefore a purpose of the present invention to provide a slide rail device for a vehicle seat which prevents the separation of its upper rail from its lower rail, positively, without the necessity of forming the device of heavier weight materials.

In accomplishing this purpose according to the present invention, a lower rail is formed such as to enclose an upper rail entirely to thereby 1 i -i li- r- 6 404444 0 4 04 ,p 4 0i~ 4 0D 4 o 04d 00 00 4 O 0 0 0g 0 4~ 00 o e o 0a prevent the separation of the upper rail from the lower rail. In other words, the lower rail has an upper inwardly curved portion at its both ends and the lower rail is formed at its upper portion with a shoulder portion, the arrangement being such that the upper inwardly curved portion of the lower rail is disposed above the shoulder portion of the upper rail so as to receive a part of the shoulder portion, thus providing a limit against the 10 upward movement of the upper rail, and further that the lateral wall portion of the lower rail adjacent the upper inwardly curved portion is oriented in a direction identical to a pulling force caused at a seat belt anchored at the upper rail, thereby avoiding deformation of the upper inwardly curved portion due to such pulling force.

In addition, the upper rail is further so formed that its shoulder portion is curved in a manriner enclosing the end of the upper inwardly curved portion of the lower rail, whereby, when the upper rail is moved upwardly, the shoulder portion and its partial area sandwich the end of the upper inwardly curved portion, to ensure avoiding the deformation of the upper inwardly curved portion.

Accordingly, the reliability for preventing i 7 the separation of both upper and lower rails is almost completely attained in comparison with the conventional slide rail devises.

BRIEF DESCRIPTION OF THE DRAWINGS o Fig. 1 is a cross-sectional view of a cono ventional device; o 00 "^Ooo Fig. 2 is a cross-section view of the coventional device, showing the state in which a upward pulling 0 o force is applied to the device; o Fig. 3 is a cross-sectional view of a slide o o rail device in accordance with the present invention; o o Fig. 4 is a cross-sectional view of the same device of the present invention, showing the state in which an upward pulling force has been applied to the device; Fig. 5 is an exploded perspective view of the device in which an upper rail is integrally formed with a seat frame; and Fig. 6 is an exploded perspective view of the device which is formed independently of a seat frame.

-e i 8 DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION 5 Referring to Figs. 3 through 6, 0 P an embodiment of slide rail device in accordance a S"o with the present invention is illustrated.

o As shown, the slide rail device is designated i by numeral which comprises a lower rail (12) fixed on a floor of vehicle (11) and an upper rail °oo° (14) slidably secured on the lower rail on which on) upper rail is mounted a seat (not shown).

00 o A seat frame (16) may be integrally formed on the upper rail (14) as in Fig. 5, or may be formed independently of the upper rail (14) as in Fig. 6.

o In the latter embodiment, the upper rail (14) is fixed to the seat frame (16) by inserting and fixing a suitable means such as a screw in a hole (19) perforated in the upper rail (14).

Hereinafter, a specific description will be given on the basis of such upper rail (14) formed j separately from the seat frame (16) in Fig. 6.

Referring now to Fig. 3, the upper rail (14) comprises a main plate (18) and an auxiliary plate both of which are welded together, such that 9 their lower portions extend downwardly in a bifurcated and symmetrical manner, and are each formed with a substantially U-shaped shoulder portion a lateral wall portion (34) and an inwardly bent portion 5 all of those portions being integral and o 0 continuously formed with each other. In this respect, o a P a vertical portion (36) extends continuously upwardly f0 from the inner end portion of the shoulder portion while from the outer end portion of the shoulder portion (30) the lateral wall portions (34) continuously '0oO extend downwardly defining a protrudent bent portion o o (31) therebetween.

041 o The lower rail (12) is formed by bending one unitary plate into a configuration enclosing the upper rail such that it comprises a pair of upper inverted U-shaped portions (28) each terminating in an end (28a), a pair of inwardly inclined lateral wall portions and a pair of lower outwardly curved portions (26).

Those upper and lower rails (14)(12) are assembled together in such a manner that the lower rail (12) encloses the upper rail with the inwardly inclined lateral wall portions (32) and upper inverted U-shaped portions (28) of the lower rail (12) extending respectively along the lateral wall portions (34) and substantially U-shaped shoulder .i portions Also the upper inverted U-shaped portions (28) are disposed above the protrudent bent portions and the ends (28a) of the upper inverted U-shaped portions (28) extend into each of the substantially U-shaped 0 shoulder portions (30) A steel ball (22) is 0 embraced between the outwardly curved portion (26) 0 and inwardly bent portion (24) for the purpose 0 0 o o of facilitating the sliding movement of the upper *0 0 rail (14) along the lower rail It may be S0 that a pair of the steel balls (22) are no disposed at two points in the rails for instance, as in Fig. 5, so that vertical and horizontal 0on a 0 forces 'being applied are effectively absorbed by the balls (22) for preventing the rails o (12) from rattling.

A seat belt (40) has an end portion fixed to the vertical portion (36) of the upper rail (14) by means of a seat belt anchor means (41).

It is noted that the above-mentioned upper inverted U-shaped portions (28) of the lower rail i (12) and substantially U-shaped shoulder portions of the upper rail (14) are both so formed as to extend over the entire length of the rails (12)(14) J I I in the longitudinal direction thereof.

As best shown in Fig. 3, the inwardly inclined lateral wall portions (32) of the lower rail (12) are 11 obliquely oriented in a direction identical to an' applying direction of an upward pulling force which is exerted upon o the upper rail (14) via the seat belt (40) in a sudden D deceleration case due to a collision. y Experiments Jin this regard show that in most cases an upward pulling force caused at a seat belt is directed obliquely an approx. 30-degree angle r&Lative to the verticail and therefore it is preferable that the inwardly inclined lateral wall portion (32) should be strictly oriented at 30-degree angle in conformity with the direction of the upward pulling Oforce F) B u t, such inclination nay sat.isfactorily fall within the'angle, ranges of 25 to 35 degrees.

With the above-mentioned structure, when the upward pulling force is applied to the upper rail tending to raise it up from the lower rail (12), the protrudent bent portions( 3 l) and shoulder portions of the upper rail (14) are brought into abutment against the upper inverted U-shaped portion (28) and its end (28a), of the lower rail respectively.

A t this p o in t, the upper inverted U-shaped portion 11 12- (28) is subjected to a bending moment caused by .the pulling force and is being forcibly bent upwardly, but the inclination of the lateral wall portion of lower rail (12) at an angle substantially conforming 5 to the direction of the pulling force serves to ooQeoc 0 0 reduce the bending moment, whereupon the inverted U-shaped portion (28) is not easily bent or deformed o ,upward.

In this context, it is preferable that the lateral wall portion (34) of the upper rail (14) be o0o formed substantially in parallel with the inwardly 0 inclined lateral wall portion By being so o formed, the latter portion (32) is brought to an entire contact with the former portion i when the bending moment is caused therein, so that the portion (34) acts as a limit against the bending of the portion thus preventing the deformation of the upper inverted U-shdped portion (28) in a more positive fashion.

Further, the substantially U-shaped shoulder portion (30) is of such construction as to accommodate i the end (28a) of the upper inverted U-shaped portion i (28) in an embracing manner, which more effectively avoids the deformation of the portion (28).

Specifically, referring to Fig. 4, as the upper rail

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13 (14) is raised upwards due to the pulling force the substantially U-shaped shoulder portion (30) of the upper rail is raised accordingly to press upon the end (28a) of the upper inverted U-shaped 5 portion (28) of the lower rail and then the 0 0 <i end (28a) becomes sandwiched and retained between the Sprotrudent bent portion (31) and vertical portion (36) of the upper rail with the result that 0 the protrudent bent portion (31) and vertical portion (36) cooperate to firmly grip the end (28a) of the oa upper inverted U-shaped portion (28) at a gripping area (38) in a frictional manner. This frictional 'o gripping force caused at the gripping areas (38) is effective in preventing the deformation of the end (28a), and therefore the upper rail (14) is limited 0 o its upward movement by thus-retained end (28a) in a more assured way. Further, while the pulling force portion is being applied, the shouldeyr prf (30) becomes contracted in its U-shaped body due to the foregoing gripping effect, which renders the shoulder portion per se more rigid against any other deformation, and with such increased structural rigidity, the frictional gripping of the end (28a) at the areas (38) becomes so positive as to not only enhance the Z prevention of the end (28a) against its slipping off I ii

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14 0 00 00 0a a q 0 a a 0 DO from the shoulder portion (30) but also ensures preventing the end (28a) from deformation.

Accordingly, the end (28a) of the upper inverted U-shaped portion (28) is protected against deformation and functions to limit the upward movement of the upper rail Also, the shoulder portion of the upper rail (14) is prevented against both its deformation and upward displacement. The upper rail therefore, is not raised any further, and its separation from the lower rail (12) is completely eliminated.

0 0aI om 0 0 00 Cl 00 0 o 0 SIt is especially important to note that the S" greater the pulling force which is applied the more firmly gripped the upper inverted U-shaped portion S 15 (28) of the lower rail (12) by the shoulder portion of the upper rail and thus the device of the present invention is of a sufficiently robust structure to withstand an extremely great pulling force exerted thereupon and to prevent its undesired deformation, and further it can be made of a relatively thin steel plate, allowing the production of smallsized and light-weight slide rail device having such robust structure ensuring prevention of the separation of the upper rail (14) from the lower rail (12).

While in the embodiments having been described ~u~iatu,~~su~~l before, the slide rail device (10) is provided on the right and left sides of the seat, it not always necesary to provide the device (10) in such fashion, but only one device (10) may be provided on the side of the seat where the seat belt (40) is attached.

Practically, providing the device (10) on both sides o of the seat, however, gives much more reliability o in preventing the separation of the rails (12)(14).

All the descriptions above have just been given of preferred embodiments of the present invention, but it should be understood that the invention is "not limited to the embodiments illustrated but other replacements, modifications and addtions may 0 structurally be possible without departing from the spirit of the invention. For o 0 example, in the illustrated embodiment, the lower portions of the main and auxiliary plates (18)(20) extend in a bifurcated and symmetrical manner, but the upper rail (14) may have only one lower portion of an identical shape to that of the main plate (18) at the same side the lower portion of main plate i (18) which is shown in Figs. 3 and 4 as being disposed on the left), considering the fact that the obliquely applied pulling force is mostly exerted on the J lower portion of the main plate (18).

16 From the above description, it is accordingly appreciated that the slide rail device according to the present invention is so rigid as to withstand a great bending moment caused by an upper pulling o 5 force applied by an occupant about to be thrown out in a collision and as such the rail members thereof are almost completely prevented from o a o deformation, and particularly the upper inverted 0000', U-shaped portion (28) of the lower rail (12) is advantageously protected by the substantially U-shaped shoulder portion (30) against its deformation and slipping off from the device, whereby the portion O S (28) retains its function for limiting the upward movement of the upper rail even if an extreme ioo 15 great pulling force is applied thereto. Thus, the separation of the upper rail (14) from the lower rail (12) is positively prevented.

Moreover, the upper and lower rail can be made of a relatively thin steel plate, and it is not necessary to form the rails of a thick cross-section material and therefore the production of a small-sized and lightweight slide rail device having a sufficient rigidity permitted.

Claims

1. A slide rail device for a vehicle seat comprising a lower rail fixed on a floor of said vehicle, s an upper rail slidably fitted to said lower rail, and a seat belt which is at one end portion secured to said P upper rail, wherein said lower rail comprises a pair of inwardly inclined lateral wall portions so formed 0 their upper part is inclined relative to their lower part aC 0 a in a direction inwardly of the lower rail, and further0 a comprises a pair of upper inverted-U-shaped portions0 0* formed continuously from an upper end of said inwardly a oaoa inclined lateral wall portions, and wherein said uppera04A rail having its lower portion extending downwardly in a 1 100 bifurcated and symmetrical manner comprises a lateral wall C O Do .0 0 Q DO da portion disposed under said inwardly inclined lateral wall 0'.0 00 prinof said lower rail, and further comprises a 0 poto 0 sa eahu drp r in fr e 0 ~substatal a 0 continuously from said lateral wall portion, said shoulder Dean portion being disposed under said upper inverted-U-shaped0t portion of said lower rail, whereby when an upward pulling force is exerted on said upper rail through said seat belt, said lateral wall portion of said upper rail is brought to contact with said inwardly inclined lateral wall portion and said ITI <1 h 18 118 substantially U-shaped shoulder portion of said upper rail is contracted to grip said upper inverted-U-shaped portion of said lower rail.

2. The slide rail device according to Claim 1, wherein said inwardly inclined wall portion of said lower rail is inclined in conformity with a direction of said pulling force exerted on said seat belt.

3. The slide rail device according to Claim i, wherein said lateral wall portion of said upper rail is so formed as to extend in parallel with said inwardly inclined wall portion of said lower rail. Q 4 t

4. The slide rail device according to Claim i, wherein said lower rail is formed such that said inwardly inclined portion thereof is provided at least only at an outer side of said lower rail.

The slide rail device according to Claim 1, wherein said upper inverted-U-shaped portion of said lower rail extends over an entire length of said lower rail in a longitudinal direction thereof, 19 19 and said substantially U-shaped shoulder portion of said upper rail extends over an entire length of said upper rail in a longitudinal direction thereof.

6. The slide rail device according to Claim I, wherein said upper rail comprises a main plate and an auxiliary plate welded integrally to said main plate, such that the lower portions of said main and auxiliary plates extend in a bifurcated a All 9 and symmetrical manner, and are each formed with said substantially U-shaped shoulder portion, said lateral o0 Sportion, and a first curved portion adapted to retain 0 a ball means, and wherein said lower rail comprises a flat bottom portion, a pair of said inwardly inclined lateral wall portionq which respectively extend upwardly from right and left sides of said flat bottom portion, and a second curved portion adapted to retain said ball means so that said ball means is embraced between said first and second curved portions, said second curved portion being formed continuously with each of said inwardly inclined lateral wall portions

7. The slide rail device according to Claim 1, wherein said inwardly inclined lateral wall portion of said lower rail is inclined at an angle 1 i tIi? I I: oi a Q at 1 01 o cO 00 0 aI a 20 range from 25 degrees to 35 degrees relative to a vertical line.

8. The slide rail device according to 5 Claim 1, wherein a seat frame is integrally fixed on said upper rail.

9. The slide rail device according to Claim 1, wherein a plurality of ball means are located 10 between said first and second curved portions respectively of said upper and lower rails.

10. The slide rail device according to Claim 1, wherein said substantially U-shaped shoulder 15 portion is so formed as to accommodate an end portion of said upper inverted-U-shaped portion

11. The slide rail device according to Claim 1, wherein said slide rail device is provided only at one side of the seat where said seat belt is secured. DATED THIS 1ST DAY OF MARCH 1988 TACHI-S CO., LTD. By its Patent Attorneys: CLEMENT HACK CO. Fellows Institute of Patent Attorneys of Australia. o :B t a