CA1266610A - Seat slide device - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A seat slide device adapted to adjust the forward and rearward positions of an automobile seat, comprising an upper rail, a lower rail, the upper rail being slidably fitted to the lower rail, and a reinforcing member. The reinforcing member is fixed to the upper rail and has a plurality of claw members which are engageable with the lower rail. When a pulling force is applied to the upper rail, the claw members are engaged with the lower rail so as to prevent the removal of the upper rail from the lower rail as well as the longitudinal dislocation of the upper rail relative to the lower rail.

Description

The present invention relates to a seat slide device for an automotive seat, which is adapted to adjust the forward and backward positions of the seat, and more particularly relates to an improvement on a seat slide device comprising upper and lower rails, the upper rail being slidably fitted to the lower one, in which a seat belt is at its one end anchored to the upper rail, in order that the upper rail is prevented from its removal out of the lower rail.
Most of generally designed seat slide devices are essentially composed of a lower rail to be fixed to the floor of an automobile and an upper rail to be fixed to the bottom surface of a seat, with such an arrangement that the upper rail is fitted to the lower rail in a slidable fashion. In actual use, a pair of thus-constructed slide devices are each provided on the respective lateral sides of a seat.
In a conventional seat slide device, a roller is disposed between a lower rail and an upper rail, and a steel ball is embraced by both an inwardly bent edge of the upper rail and an outwardly bent edge of the lower rail. It is, then, understandable that a vertical force is exerted on the roller whereas vertical and transverse forces are exerted on the steel ball.
The advantage of such prior art, therefore, is that there is no possibility of the upper rail being dislocated vertically or laterally relative to the lower rail, allowing the former rail to smoothly slide along the latter rail.

~2666~

A locking structure is in most cases arranged in the foregoing seat slide device, such that a plurality of equidistant projected pieces are formed on the upper rail and a plurality of lock apertures are formed in the lower rail in correspondence with the respective projected pieces. With the arrangement the upper rail can be locked at a desired position on the lower rail when the projected pieces are brought into engagement with the respective lock apertures.
In the above-mentioned device per se, there is no problern in the case of a sudden accident like a collision taking place, with a great load applied thereto. This is particularly the case when a seat belt is not attached around the body of an occupant on the seat. The reason is that, in such accident, the upper and lower ralls are given a maximum load only when the occupant is forced backwards forcing his body against the seat back of his seat provided on those rails. At such times, due to the load upon the seat back, an upward pulling force is exerted on the forward point where the forward end portion of the seat is connected with the corresponding portion of the upper rail. At the same time a downward pressing force is exerted on the rearward point where the rearward end portion of the seat is connected with the corresponding portion of the upper rail. The former pulling force, although tending to remove away the forward end portion of the upper rail from the lower rail, is not so great as to remove the upper rail. Therefore, the seat slide : . .. . . .
.

; ' ' ' ~' ., ~': - ... .'' . : ' ~666~

device is not damaged insuch case.
However, in view of recent circumstances making the attachment of a seat belt mandatory and a legal requirement for drivers and others who sit on automotive seats, every automobile has seat belts mounted therein.
When it is desired to fix one end of the seat belt to the seat frame of the seat or the upper rail of the seat slide device, the aforementioned type of conventional seat slide device is not rigid enough to resist such upward pulling force caused by a collision or the like.
In other words, when a seat belt is fixed to the upper rail or the seat fxame disposed thereon, when a collision occurs, the seat bel-t, which holds an occupant in the seat, is pulled by the forward inertia Eorce of the occupant, transmitting a maximum pulling force to the seat slide device. In this case, a downward press-ing force is exerted on the above-discussed forward point ( a point where the forward end portion of the seat is connected with the upper rail , and an upward pulling force is exerted on the above-discussed rearward point ( a point where the rearward end portion of the seat is connected with the upper rail). The latter upward pulling force is far greater than the above-mentioned upward pulling force which is caused in the case where a seat belt is not used. As a result, the upper rail is forcibly moved upwards, with the inwardly and outwardly bent edges of the lower rail being deformed, increasing the possibility of the upper rail being removed ~:

., ~: : - ,.

~2~66~

out of the lower rail. If the upper rail is removed from the lower one, it will be inevitable that the occupant will be thrown out forwardly together with the seat resulting in a possible fatality.
To solve this problem, there are some conventional devices using an upper rail and lower rail of large cross-section, or upper and lower rails of thick steel plate to reinforce its rigidity in order to avoid deformation of those rails as well as removal of the upper rail.
These proposals have been found defective in that a large cross section results in unfavorably big dimensions for the device, taking up a large space, and further increasing the weight thereof. Thick rails also lead to the same result.
The present invention provides an improved seat slide device whose rigidity is effectively reinforced in a simple manner without need for designing a large and weight-increased structure, so as to prevent the removal of an upper rail from a lower rail.
The present invention comprises an upper rail, to be fixed to a seat, a lower rail to be fixed to a floor ~f an automobile, and a reinforcing member, the lower rail being slidably fitted to the upper rail such that it encloses the latter upper rail. The reinforcing member is fixed to the upper rail. The lower rail is at its upper edge portion formed with an inverted U-shaped flange which includes engagement means having a plurality of recessed portions. The reinforcing member includes a plurality of spaced-apart claw members each having an ., :

~2~6~

inwardly directed protrusion, wherein the inverted U-shaped flange is disposed over the spaced-apart claw members.
With the above-described construction, when a load is applied to the upper rail, tending to remove the upper rail out of the lower rail, the protrusions of the claw members are brought into engagement with the recessed portion of the engagement means of the lower rail, whereby such engagement prevents removal of the upper rail from the lower rail.
Preferably the engagement means of the lower rail are provided with stopper means which serve to prevent the longitudinal displacement of the upper rail relative to the lower rail at the time when the protrusions of the claw members are engaged with the recessed portion of the engagement means.
In the drawings, Fig. 1 is a cross-sectional view of a conventional seat slide device, showing the state in which no pulling force (F) is applied thereto:
Fig. 2 is a cross-sectional view of the same conventional seat slide device, showing the state in which pulling force (F) has been applied thereto;
Fig. 3 is a cross-sectional view of a seat slide device in accordance with the present invention, showing the state in which no pulling force (F) is applied thereto;

Fig. 4 is an exploded perspective view of the seat slide device in accordance with the present invention;

6~
Fig. 5 is an exploded perspective view of the seat slide device of the present invention which is assembled together with a seat frame;
Fig. 6 is an exploded perspective view of the seat slide device of the present invention which is assembled independently of the seat frame;
Fig. 7 is a partially exploded perspective view of a lower rail and reinforcing member in accordance with the present invention;
Fig. 8 is a cross-sectional view of the seat slide device in accordance with the present invention, showing the state in which a pulling force (F) has been applied thereto;
Fig. 9 is a longitudinally sectional view taken along the line VII - VII in the Fig. 7;
Fig. 10 is a partially exploded perspective view showing a lower rail and reinforcing member in accordance with a second embodiment of the present invention;
Fig. 11 is a longitudinally sectional view taken along the line IX - IX in the Fig. 10;
Fig. 12 is a cross-sectional view taken along the line X - X in the Fig. 10;
Fig. 13 is a partially exploded perspective view showing a lower rail and reinforcing member in accordance with a third embodiment of the present invention;
and, Fig. 14 is a longitudinally sectional view taken along the line XII - XII in the Fig. 13.
Referring to Fig. 1 of the accompanying drawings, .

:.: . : . ',''- -: - ~ :

.: . . . -illustrated is an example of conventional seat slide device of this kind. In this particular device, a roller 50 is disposed between a lower rail 112 and an upper rail 114, and a steel ball 122 is embraced by both inwardly bent edge 128 of the upper rail 114 and outwardly ben~ edge 124 of the lower rail 112. It is, then, understandable that a vertical force is exerted on the roller S0 whereas vertical and transverse forces are exerted on the steel ball 122.
The advantage of such prior art, therefore, is that there is no possibility of the upper rail 114 being dislocated vertically or laterally relative to the lower rail 112, allowing the former rail to smoothly slide along the latter rail.
In the above-mentioned device per se, there is no problem in the case of a sudden accident like a collision taking place, with a great load applied thereto. This is particularly the case when a seat belt is not attached around the body of an occupant on the seat. The reason is that, in such accident, the upper and lower rails 114 112 are given a maximum load only when the occupant is forced backwards forcing his body against the seat back of his seat provided on those rails. At such times, due to the load upon the seat back, an upward pulling force is exerted on the forward point where the forward end portion of the seat is connected with the corresponding portion of the upper rail. At the same time a downward pressing force is exerted on the rearward point where the rearward end portion of the seat is connected " i. .

-: , .. ,., :, -: - : : :. ", , . ~ .

. . - . . ,. :::. .: - - :: :,- .

;~26~V

with the corresponding portion of the upper rail 114.
The former fulling force (designated by "F" in Figs. 1 and 2), although tending to remove away the forward end portion of the upper rail 114 from the lower rail 112 in an arrow direction as in Fig. 1, is not so great as to remove the upper rail 114.
When a seat belt is fixed to the upper rail 114 or the seat frame disposed thereon, when a collision occurs, the seat belt, which holds an occupant in the seat, is pulled by the forward inertia force of the occupant, transmitting a maximum pulling force to the seat slide device. In this case, a downward pressing force is exerted on the above-discussed forward point (a point where the forward end portion of the seat is connected with the upper rail 114), and an upward pulling force is exerted on the above-discussed rearward point (a point where the rearward end portion of the seat is connected with the upper rail 114). The latter upward pulling force is far greater than the above-mentioned upward pulllng force which is caused in the case where a seat belt is not used. As a result, as shown in Fig.

2, the upper rail 114 is forcibly moved upwards, with the inwardly and outwardly bent edges of the lower rail 112 being deformed increasing the possiblity of the upper rail 114 being removed out of the lower rail 112.
Figs. 3 and 4 illustrate a seat slide device 10 in accordance with the present invention. The seat slide device 10 comprises a lower rail 12 to bè fixed to a floor 11 of an automobile, an upper rail 14 to be fixed :......... . ~ . . ..

66~

to a floor 11 of an automobile, an upper rail 14 to be fixed to the bottom surface of a seat (not shown), the upper rail 14 being slidably fitted to the lower rail 12, and reinforcing member 30 fixed to the upper rail 14.
The upper rail 14 may be assembled integrally with a seat frame 16 (See Fig. 5), or assembled independently of the seat frame 16 (See ~ig. 6).
Hereinafter, the description will be directed particularly to the independently formed seat as shown in Fig. 6.
As illustrated, the upper rail 14 is comprised of a base plate 18 and an auxiliary plate 20. Both base and auxiliary plates 18 20 are welded together such that their respective lower portions extend downwardly in a symmetrical distant relation and terminate in inwardly arc-shaped end portions 24. Further, each of the base and auxiliary plates 18 20 has a shoulder portion in which are formed a plurality of rectangular holes 36.
The lower rail 12 is basically formed by bending a unitary steel plate into a substantially U-shaped configuration, with an outwardly arc-shaped guide passage 26 formed midway in each of the vertical side walls of thus-formed lower rail 12 and an inverted U-shaped flange 28 integrally formed in each of the upper end portions of the lower rail 12.
The above-mentioned upper and lower rails 14 12 are assembled together in such a manner that the lower rail 12 encloses the upper rail 14 and steel balls 22 are embraced by both the inwardly arc-shaped end portions 24 - 9 _ .. ., . - , - ....................... . .... .. .
. . .. ~.. .. ,: ., : :

:. : , . ,~. .,.: ~ - :. . , ; :

~26~6~

of the upper rail 1~ and outwardly arc-shaped yuide passage 26 of the lower rail 12~
The upper rail 14 is fixedly secured to the seat frame 16 by inserting such securing means as bolts through holes 19 in the base plate 18.
It is seen that the provision of the steel balls 22 between the upper and lower rails 14 12 is effective in resisting a transverse force applied to the upper and lower rails 1~ 12 . It may be arranged tha-t at leas-t one roller (not shown) is disposed between the interior oE the upper rail 14 and the bottom por-tion of the lower rail 12. In this way, it is possible to provide bo-th vertical-force and transverse-force resistances in the upper and lower rails 1~ 12 so that the upper rail 14 can be smoothly and slidingly moved on the lower rail 12 without any vertical and transverse disloca-tion.
As best shown in Fig. 4, the reinforcing member 30 has a plurality of claw members 32 projecting upwardly therefrom, the arrangement of the claw members 32 being such that they constitute a pair of rows respectively provided along the right and left ends of the reinforcing member 30 in a symmetrical fashion, with the claw members 32 per se being spaced apart from each other at a certain distance in the longitudinal direction. Preferably, the claw members 32 are formed at a pitch corresponding to respective lock apertures(not shown) formed in the seat slide device 10.
The claw members 32 are not limited to this embodiment, bu-t may be formed only in one end of the . ~ ,,~,............... ..

~266S~
reinforclng member 30.
The reinforcing member 30 is fixed to the lower portion of the upper rail 14 by means of welding or the like in an integral manner, such that the claw members 32 are respectively inserted through each of the rectangular holes 36, projecting upwardly therefrom.
As best shown in Fig. 7, each of the claw members 32 is provided at its upper end with a protrusion 38 directed inwardly of the reinforcing member 30.
It should be noted that the lower rail 12 is slidably fitted to the upper rail 14 in a manner enclosing the upper rail 14 such that the inverted U-shaped Elange 28 of the lower rail 12 ex-tends over and circumscribes the upper por-tions of the claw members 32 of the rein-forcing member 30.
Each inverted U-shaped flange 28 is formed along one longitudinal edge with engagement means 40 adapted to be interengageable with the protrusions 38 of the claw members 32. In the present embodiment, as shown in Figs. 3 and 7, the engagement means 40 include a projection 29 formed at the inner edge of the inverted U-shaped flange 28 and projecting therefrom in a direction inwardly of the inverted U-shaped flange 28 towards the claw members 32. A recessed portion 42 is formed above the projection 29.
The recessed portion 42 is so designed that it will receive the protrusions 38 of the claw members 32.
In addition, the engagement means 40 are provided with stopper means 44 which are adapted to prevent the :.. ., . . :.

~2~

longitudinal displacement of the upper rail 14 relative to the lower rail 12 when the protrusions 38 of the claw members 32 are brought to engagement with the recessed portion 42 of the engagement means 40.
Both recessed portion 42 and engagement means 40 can easily be ob-tained by press forming the lower rail 12 in a proper manner.
The stopper means 44, in particular, are formed by subjecting to a press working process the inverted U-shaped flange 28 adjacent to the engagement means 40 so as to provide a plurality of dent portions 40a in the inner surface of the inverted U-shaped flange 28 at an interval corresponding to each of the claw members 32. It is observed here that at the outer surface of the inverted U-shaped flange 28, formed also are a corresponding number of raised portions 40b at points corresponding to the dent portions 40a, which efEectively adds to the rigidity of the inverted U-shaped flange 28.

Designation (a) denotes an area for connecting with an end of a seat belt tnot shown).
Now, when a collision or the like occurs, an occupant of the seat is forced out forwardly from the seat, creating a pulling force on his or her seat belt. Then, a great upward pulling force is exerted upon the upper rail 14, tending to remove the same out of the lower rail 12. More precisely, the upper rail 14 is given an upward component force and a forward component of force, namely, a diagonal forward vector of the pulling force. Thus, the upper rail 14 is caused to move in a diagonal forward direction.

;6~

Thus there is a great possibility of the upper rail 14 being not only dislocated longitudinally relative to the lower rail 12, but also being removed upwardly away from the lower rail 12.
Assuming that the pulling force (F) is of the foregoing nature, both upper rail 14 and reinforcing member 30 are moved slidingly in a forward direction along the inverted U-shaped flange 28, and at the same time, they are moved upwardly with the result that the protrus-ions 38 of the claw members 32 are brought into contactwith the inner surface of the inverted U-shaped flange 28.
This results in a positive interengagement between the upper and lower rails 14 12 as shown in Fig. 8. Due to such interengagement of both rails 14 12, vertical displacement of the upper rail 14 is prevented and also its removal out of the lower rail 12. Furthermore, a friction is created between the protrustions 3B and the inner surface of the inverted U-shaped flange 28, which prevents the longitudinal movement of the upper rail 14, thus avoiding a forward dislocation of the upper rail 14 relative to the lower rail 12.
Thereafter, as the pulling force (F) continues to be exerted on the upper rail 14, both right and left rows of claw members 32 are respectively pressed against the inverted U-shaped flange 28 so as to be bent outwardly.
On the other hand, the right and left inverted U-shaped flanges 28 are also bent outwardly to a greater degree than the claw members 32 because the balls 22 are pressed upwardly by the inwardly arc-shaped end portions 24 of the ~26G~

upper rails 14. The respective flanges 28 are pressed and ben-t outwardly with respect to the center axis of the balls 22. As a result, the protrusions 38 of the claw members 32 are brought into engagement with the recessed portions 42 of the engagement means 40, respectively, and further the protrusions 3~ are received in the dent portions 40a, respectively. This engagement further prevents in a positive manner the longitudinal dislocation of the upper rail 14 relative to the lower rail 12 as well as the further upward movement of the upper rail 14 from the lower one 12. It will be appreciated that -the grea-ter the pulling force (F) applied to the upper rail 14, the more firmly is engaged the protrusions 38 with bo-th recessed portions 42 and dent portions 40a, so that the present structure is quite rigid and able to resist a high pulling force. Consequently, any further upward movement oE the upper rail 14 and reinforcing member 30 is almost completely prevented, and thus the upper rail 14 is prevented from being removed from the lower rail 12.
In addition, such engagement of the protrusions 38 with both recessed portions 42 and dent portions 40a is a simple and yet firm, providing a good answer to deformation problems. Accordingly, there is no need to provide upper and lower rails with a large cross-section and the present invention can be made with thin steel plates, so that the seat slide device 10 per se is quite small in size with reduced relative weight and sufficient rigidity.

- : . .
':;
.

~Z66~

The engagement means 40 are not limited to the illustrated embodiments, but may be formed in various ways so long as they are so designed as to be engageable with the protrusions 38 of the claw members 32 for the purpose of avoiding the removal of the upper rail 14 from the lower rail 12.
Figs.10 through 12 illustrate another exemplary form of engagement between the claw members 32 and inverted U-shaped flange 28. The claw members 32 are each formed at the upper end thereof with a raised portion 138 projecting inwardly of the reinforcing member 30. The inverted U-shaped flange 28 is at its downwardly extending end portion formed with a plurality of recessed portions 142 so arranged that each of them is disposed in the inner surface of the flange 28 at a point corres7 ponding to the respective raised portions 138. According to this embodiment, the raised portions 138 are to be engaged with the respective recessed portions 142.
Figs. 13 through 14 illustrate still another form of engagement between the claw members 32 and inverted U-shaped flange 28. Here the claw members 32 are each formed with an upwardly extending raised portion 238 which runs from the foot to the top of the claw member 32.
The inverted U-shaped flange 28 is formed with a plurality of elongated recessed portions 242 which are so formed that each of them runs in the inner surface of the flange 28, extending from the inner edge to the curved top portion of the flange 28, and is disposed at a point corresponding to the respective raised portion 238.

.

,' .' ' ' ' ,;i :: ~ .. ',: , The above-mentioned two embodiments shown in Figs. 10 - 14 are preferably formed by means of a press working method.
While, in the embodiments that have been described above, the seat slide device 10 is provided on the right and left sides of the seat, it is not always necessary to provide the device 10 in such fashion, depending on the design of the seat.
The description above is of preferred embodiments of the present invention, but it should be understood that the invention is not limited to the embodiments illustrated. Other replacements, modifications and additions may structurally be possible without departing from the spirit of the invention.

:`~ ' ' ''~' -.

`. ' `' .' ~ "" ... . ..

Claims (9)

1. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
   
   l. A seat slide device, which has a lower rail to be fixed to a floor of an automobile and an upper rail to be fixed to a seat, the upper rail being slidably fitted to the lower rail, said seat slide device comprising:
   a reinforcing member fixed to said upper rail, said reinforcing member having a plurality of claw members which are spaced apart from each other at a predetermined distance;
   
   each of said claw members having a protrusion which projects inwardly thereof;
   an inverted U-shaped flange formed in an upper edge portion of said lower rail and engagement means provided in said inverted U-shaped flange, said engagement means including a plurality of recessed portions adapted to be engageable with the protrusions of said claw members, wherein said lower rail is slidably fitted to said upper rail in a manner enclosing the upper rail such that said inverted U-shaped flange of the lower rail is disposed above said claw members of said reinforcing member, whereby, when a pulling load is applied to said upper rail, tending to remove said upper rail from said lower rail together with said reinforcing member, said protrusions of said claw members are respectively engaged with said recessed portions of said engagement means, to thereby prevent removal of said upper rail from said lower rail.
2. 2. The device according to Claim 1, wherein said engagement means are provided with stopper means adapted to prevent a longitudinal dislocation of said upper rail relative to said lower rail when said pro-trustions of said claw members are engaged with said recessed portions of said engagement means.
3. 3. The device according to Claim 1, wherein said upper rail is integrally formed with a seat frame of said seat.
4. 4. The device according to Claim 1, wherein said upper rail comprises a base plate and an auxiliary plate, the formation of the base and auxiliary plates being such that they extend downwardly in a symmetrically spaced-apart relationship and terminate respectively in an inwardly arc-shaped end portion, wherein said lower rail is formed by bending a unitary rigid plate, with an outwardly arc-shaped portion formed midway in each of vertical side walls of said lower rail and said inverted U-shaped flange formed in each of upper edge portions of said lower rail and wherein a ball is embraced by and between said inwardly arc-shaped end portion and said outwardly arc-shaped portion.
5. 5. The device according to Claim 1, wherein said claw members of said reinforcing member are so arranged that they constitute a pair of rows respectively provided along the right and left sides of said reinforcing member and are spaced apart longitudinally from each other at a distance corresponding to that of respective lock apertures formed in said lower rail.
6. 6. The device according to Claim 4, wherein said reinforcing member is fixed to a lower portion of said upper rail in such a manner that said claw members are respectively inserted through each of rectangular holes formed in said base and auxiliary plates, projecting upwardly therefrom.
7. 7. The device according to Claim 1, wherein said engagement means includes a projection formed at an edge of said inverted U-shaped flange in a manner so as to project in a direction inwardly of said inverted U-shaped flange towards said claw members, and a recessed portion disposed above said projection.
8. 8. The device according to Claim 1, wherein said claw members are each formed with a raised portion projecting inwardly of said reinforcing member and said inverted U-shaped flange is formed with a recessed portion to be engageable with said raised portion, by means of a press working method.
9. 9. The device according to Claim 1, wherein said claw members are each formed with an upwardly extending raised portion which runs from a lower portion of said claw member to the top of the same and wherein said inverted U-shaped flange is formed with a plurality of elongated recessed portions which run from an inner edge of said flange to a curved top portion of the same, said elongated recessed portions being engageable with the upwardly extending raised portions.