CA1284939C - Slide rail device for vehicle seat - Google Patents
Slide rail device for vehicle seatInfo
- Publication number
- CA1284939C CA1284939C CA000561160A CA561160A CA1284939C CA 1284939 C CA1284939 C CA 1284939C CA 000561160 A CA000561160 A CA 000561160A CA 561160 A CA561160 A CA 561160A CA 1284939 C CA1284939 C CA 1284939C
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- Canada
- Prior art keywords
- rail
- lower rail
- lateral wall
- slide rail
- upper rail
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 238000000926 separation method Methods 0.000 abstract description 9
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000009751 slip forming Methods 0.000 description 1
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- Seats For Vehicles (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A slide rail device for a vehicle seat adapted for adjustment of fore-and-aft positions of the seat, comprising an upper rail fixed to the seat and a lower rail slidably fitted to the upper rail, with one end of a seat belt being secured to the upper rail, in which the lower rail encloses the upper rail, with such an arrangement that an upper inverted-U-shaped portion of the lower rail is disposed above a substantially U-shaped shoulder portion of the upper rail, a lateral wall portion of the lower rail is inclined in conformity with a direction of an upward pulling force exerted via the seat belt upon the upper rail, and the shoulder portion of the upper rail is so formed as to accommodate the end of the upper inverted-U-shaped portion of the lower rail, to thereby prevent the separation of the upper rail from the lower rail.
A slide rail device for a vehicle seat adapted for adjustment of fore-and-aft positions of the seat, comprising an upper rail fixed to the seat and a lower rail slidably fitted to the upper rail, with one end of a seat belt being secured to the upper rail, in which the lower rail encloses the upper rail, with such an arrangement that an upper inverted-U-shaped portion of the lower rail is disposed above a substantially U-shaped shoulder portion of the upper rail, a lateral wall portion of the lower rail is inclined in conformity with a direction of an upward pulling force exerted via the seat belt upon the upper rail, and the shoulder portion of the upper rail is so formed as to accommodate the end of the upper inverted-U-shaped portion of the lower rail, to thereby prevent the separation of the upper rail from the lower rail.
Description
~;~8~939 The present invention relates to a slide rail device use~ 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, relates to a slide rail device of the ty~e havinq a seat belt provided on its upper rail and designed to avoid the separation of upper rail from lower rail in a sudden deceleration due to a collision accident or the like.
Hitherto, there have been known various kinds of slide rail devices for vehicle seats and among them a type of device has been in use which has a seat belt anchored thereto in order to disperse a pullinq force exerted on the seat belt to the floor of the vehicle and further so designed to prevent the disengagement of its upper rail from its lower rail for safety purposes a~ainst 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 occupant who sits on the seat provided above the upper rail, and the restraint force of the seat belt is supported on the upper rail.
q~
lZ84939 Various examples of such slide rail devices are known, for example, from the Japanese Utility ~lodel Publication No. 57-24594, or the ~.S. Patent No.
4,204,658.
Referring to the accompanying drawinqs:
Fig. 1 is a cross-sectional view of a conventional device such as the prior art devices referred to above;
Fig. 2 is a cross-sectional view of the conventional device, showing the state in which an upward pulling force (F) is applied to the device;
Fig. 3 is a cross-sectional view of preferred embodiment of a slide rail device in accordance with the present invention;
Fig. 4 is a cross-sectional view of the same device of Fig. 3 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 of Fig. 3 in which an upper rail is integrally formed with a seat frame; and ~Z84939 Fig. 6 is an exploded pers~ective view of the device of Fiq. 3 which is formed independently of a seat frame.
Hereinafter, the structural advantages and disadvantages of the prior art will be discussed with reference to the model in Fig. 1. Namely, in the prior art, a plurality of equidistant apertures (iO2) are formed in the shoulder portion (130~ of an upper rail (114), and a plurality of enqagement teeth (104), which are equidistant from one another corresponding to each of the apertures (102), are 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 the apertures lS (102). With this structure, in the case of sudden deceleration due to a collision or accident, a pullinq force (F) is applied to the upper rail (114) (See Fig. 2), which tends to raise the upper rail (114), and thus, as the upper rail (114) is moved upwardly, the teeth ~104) of the lower rail (112) are inserted into and engaged in the respective apertures (102) of the upper rail (114), as shown in Fig. 2. Accordingly, the upper rail (114) is prevented from separating from the lower rail (112).
-- 5 ~
l~owever, the pullinq force (F) being a~plied is, in fact, oriented obliquely in a direction inwardly of the slide rail device, as shown in Fiq. 2. Such pullinq force tF) is in turn exerted upon the upper curved flanqe portion (128) because of the full enqagement 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 (a), with the result that the teeth (104) are raised at the same time, as illustrated by the phantom line in Fiq. 2.
This is, in the dynamic sense, attributed to a bendinq moment caused by the pulling force (F), and in particular, a greater amount of such bendinq moment is caused in the series of the teeth (104) disposed outwardly of the device (i.e. the one disposed on the left side as viewed in Fig.
Hitherto, there have been known various kinds of slide rail devices for vehicle seats and among them a type of device has been in use which has a seat belt anchored thereto in order to disperse a pullinq force exerted on the seat belt to the floor of the vehicle and further so designed to prevent the disengagement of its upper rail from its lower rail for safety purposes a~ainst 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 occupant who sits on the seat provided above the upper rail, and the restraint force of the seat belt is supported on the upper rail.
q~
lZ84939 Various examples of such slide rail devices are known, for example, from the Japanese Utility ~lodel Publication No. 57-24594, or the ~.S. Patent No.
4,204,658.
Referring to the accompanying drawinqs:
Fig. 1 is a cross-sectional view of a conventional device such as the prior art devices referred to above;
Fig. 2 is a cross-sectional view of the conventional device, showing the state in which an upward pulling force (F) is applied to the device;
Fig. 3 is a cross-sectional view of preferred embodiment of a slide rail device in accordance with the present invention;
Fig. 4 is a cross-sectional view of the same device of Fig. 3 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 of Fig. 3 in which an upper rail is integrally formed with a seat frame; and ~Z84939 Fig. 6 is an exploded pers~ective view of the device of Fiq. 3 which is formed independently of a seat frame.
Hereinafter, the structural advantages and disadvantages of the prior art will be discussed with reference to the model in Fig. 1. Namely, in the prior art, a plurality of equidistant apertures (iO2) are formed in the shoulder portion (130~ of an upper rail (114), and a plurality of enqagement teeth (104), which are equidistant from one another corresponding to each of the apertures (102), are 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 the apertures lS (102). With this structure, in the case of sudden deceleration due to a collision or accident, a pullinq force (F) is applied to the upper rail (114) (See Fig. 2), which tends to raise the upper rail (114), and thus, as the upper rail (114) is moved upwardly, the teeth ~104) of the lower rail (112) are inserted into and engaged in the respective apertures (102) of the upper rail (114), as shown in Fig. 2. Accordingly, the upper rail (114) is prevented from separating from the lower rail (112).
-- 5 ~
l~owever, the pullinq force (F) being a~plied is, in fact, oriented obliquely in a direction inwardly of the slide rail device, as shown in Fiq. 2. Such pullinq force tF) is in turn exerted upon the upper curved flanqe portion (128) because of the full enqagement 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 (a), with the result that the teeth (104) are raised at the same time, as illustrated by the phantom line in Fiq. 2.
This is, in the dynamic sense, attributed to a bendinq moment caused by the pulling force (F), and in particular, a greater amount of such bendinq moment is caused in the series of the teeth (104) disposed outwardly of the device (i.e. the one disposed on the left side as viewed in Fig.
2). As a result, there is a great likelihood of those outwardly disposed series of teeth (104) being disenqaged out of their corresponding apertures (102) one by one.
Thus, according to the noted prior art, it is not possible to prevent the upper rail (114) from completely separating from the lower rail (112).
Of course, the foregoing problem can be solved by forming the upper and lower rails of thicker material to increase their rigidity against deformation. But, such formation of the upper and lower rails results in greater dimensions of the slide device as a whole, requiring ~284939 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 weiqht seat.
Further, in contrast to the above-mentioned prior art, there has been such a slide rail device as disclosed in the Japanese Laid-Open Utility Model Publication No.
49-106021. According to this other 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 portion of the upper rail encloses that of the lower rail. Nevertheless, it is quite possible for the upper rail to be separated from the lower one, because when a great upward pulling force is exerted on the upper rail, the curved portion of the upper rail is easily opened, resulting in the upPer rail slippinq off from the curved portion of the lower rail and becoming separated therefrom.
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 ~284939 lower rail, positively, without the necessity of forming the device of heavier weight materials.
In accomplishing this purpose accordinq to the S present invention, a lower rail is formed such as to enclose an upper rail entirely to thereby prevent the separation of the upper rail from the lower rail. In other words, the lower rail has an upper inwardly curved portion at both its 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 upward movement of the upper rail, and further that the lateral wall portion of the lower rail adjacent the upper inwardly curved portion is orientated 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 manner enclosinq the end of the upper inwardly curved portion of the lower rail, whereby, when the upper rail is moved upwardly, the ~284~39 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 the separation of both upper and lower rails is almost completely attained in comparision with the conventional slide rail devices.
Referring to Figs. 3 through 6, a preferred embodiment of slide rail device in accordance with the present invention is illustrated.
As shown, the slide rail device is designated by numeral (10), which comprises a lower rail (12) fixed on a floor of vehicle (11) and an upper rail (14) slidably secured on the lower rail (12), on which upper rail is mounted a seat (not shown).
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. In the latter embodiment, the upper rail (14) is fixed to the seat frame by inserting and fixing a suitable means such as a screw in a hole (19) perforated in the upper rail (14).
~2849~9 llereinafter, a specific description will be qiven on the basis that the upper rail (14) is formed separately from the seat frame as in Fiq. 6.
Referring now to Fig. 3, the upper rail (14) comprises a main plate (18) and an auxiliary plate (20), both of which are welded together, such that their lower portions extend downwardly in a bifurcated and symmetrical manner, and are each formed with a substantially U-shaped shoulder portion (30), a lateral wall portion (34) and an inwardly bent portion (24), all of those portions beinq integral and continuously formed with each other. In this respect, a vertical portion (36) extends continuously upwardly from the inner end portion of the shoulder portion (30), while from the outer end portion of the shoulder portion (30) the lateral wall portions (34) continuously extend downwardly defininq a protrudent bent portion (31) therebetween.
The lower rail (12) is formed by bendinq one unitary plate into a configuration enclosinq the upper rail (14), such that it comprises a pair of upper inverted U-shaped portions ~28) each terminatinq in an end (28a), a pair of inwardly inclined lateral wall portions (32), and a pair of lower outwardly curved portions (26).
1284g39 - ln -Those upper and lower rails (14) (12) are assembled together in such a manner that the lower rail (12) encloses the upper rail (14), 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 portions (30). Also the upper inverted U-shaped portions (28) are disposed above the protrudent bent portions (31) and the ends (28a) of the upper inverted U-shaped portions (28) extend into each of the substantially U-shaped shoulder portions (30). A steel ball (22) is embraced between the outwardly curved portion (26) and inwardly bent portion (24) for the purpose of facilitating the sliding movement of the upPer rail (14) along the lower rail (12). It may be that a pair of the steel balls (22) are disposed at two points in the rails (14) (12), for instance, as in Fig. 5, so that vertical and horizontal forces being applied are effectively absorbed by the balls (22) for preventing the rails (14) (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).
lZ8~9~9 It is noted that the above-mentioned upper inverted U-shaped portions (28) of the lower rail (12) and substantially ~-shaped shoulder portions (30) of the upPer rail (14) are both so formed as to extend over the entire lenqth of the rails (12) (14) in the lonqitudinal direction thereof.
As best shown in Fig. 3, the inwardly inclined lateral wall portions (32) of the lower rail (12) are obliquely oriented in a direction identical to an applying direction of an upward pullinq force (F) which is exerted upon the upper rail (14) via the seat belt (40) in a sudden deceleration case due to a collision. Experiments in this regard show that in most cases an upward pullinq force caused by a seat belt is directed obliquely at an approximate 30-deqree anqle relative to the vertical, and therefore it is perferable that the inwardly inclined lateral wall portion (32) should be oriented at 30-deqree angle in conformity with the direction of the upward pulling force (F). But, such inclination may satisfactorily fall within the angle ranqes of 25 to 35 degrees.
With the above-mentioned structure, when the upward pulling force (F) is applied to the upper rail (14), 12849~9 tending to raise it up from the lower rail (12), the protrudent bent portions (31) and shoulder portions (30) of the upper rail (14) are brouqht into abutment aqainst the upper inverted U-shaped portion (28) and its end (28a) of the lower rail (12), respectively. At this point, the upper inverted U-shaped portion (28) is subjected to a bending moment caused by the pulling force (F) and is being forcibly bent upwardly, but the inclination of the lateral wall portion (32) of lower rail (12) at an angle substantially conforming to the direction of the pulling force (F) serves to reduce the bendin~ moment, whereupon the inverted U-shaped portion (28) is not easily bent or deformed upwardly.
In this context, it is preferable that the lateral wall portion (34) of the upper rail (14) be formed substantially in parallel with the inwardly inclined lateral wall portion (32). By beinq so formed, the latter portion (32) is brought into entire contact with the former portion (34), when the bending moment is caused therein, so that the portion (34) acts as a limit against the bendinq of the portion (32), thus preventing the deformation of the upper inverted U-shpaed portion (28) in a more positive fashion.
~28~939 Further, the substantially U-shaped shoulder portion (30) is of such construction as to accommodate the end (28a) of the upper inverted U-shaped portion (28) in an embracing manner, which more effectively avoids the deformation of the portion (28). Specifically, referring to Fig. 4, as the upper rail (14) is raised upwards due to the pulling force (F), the substantially U-shaped shoulder portion (30) of the upper rail (14) is raised accordingly to press upon the end (28a) of the upper inverted U-shaped portion (28) of the lower rail (12), and then the end (28a~
becomes sandwiched and retained between the protrudent bent portion (31) and vertical portion (36) of the upper rail (14), with the result that the protrudent bent portion (31) and vertical portion (36) cooperate to firmly grip the end (28a) of the upper inverted U-shaped portion (28) at a gripping area (38) in a frictional manner. This frictional grippinq 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 in its upward movement by thus-retained end (28a) in a more assured way.
Further, while the pullinq force (F) is being applied, the shoulder portion (30) becomes contracted in its U-shaped body due to the foregoing gripping effect, which renders the shoulder portion (30) per se more rigid against any other deformation, and with such increased structural rigidity, the frictional gripping of the end (28a) at the lza4s39 areas (38) becomes so positive as not only to enhance the prevention of the end (28a) a~ainst its slipping off or from the shoulder portion (30), but also to prevent the end (28a) from deforming.
Accordingly, the end (28a) of the upper inverted U-shaped portion (28) is protected against deformation and functions to 1imit the upward movement of the upper rail (14). Also, the shoulder portion (30) of the upper rail (14) is prevented aqainst both its deformation and upward displacement. The upper rail (14), therefore, is not raised any further, and its separation from the lower rail (12) is completely eliminated.
It is especially important to note that the greater the pulling force (F) which is applied the more firmly gripped is the upper inverted U-shaped portion (28) of the lower rail (12) by the shoulder portion (30) of the upper rail (14), 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 a small-sized and light-weight slide rail device havinq such robust structure that it ensures prevention of the separation of the upper rail (14) from the lower rail (12).
1~34939 While in the embodiments havin~ been described before, the slide rail device (10) is provided on the riqht and left sides of the seat, its not always necessary 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 of the seat, however, ~ives much more reliability in preventinq 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 additions may structurally be possible without departing from the spirit of the invention. For 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 (i.e. the lower portion of main plate (18) which is shown in Fiqs. 3 and 4 as beinq disposed on the left), considering the fact that the obliquely applied pulling force (F) is mostly exerted on the lower portion of the main plate (18).
i 284939 From the above description, it is accordinqly appreciated that the slide rail device accordinq to the present invention is so riqid as to withstand a qreat bendinq moment caused by an upper pullinq 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 deformation, and particularly the upper inverted 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 (28) retains its function for limiting the upward movement of the upper rail (14), even if an extreme 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 permittinq therefore the production of a small-size and liqht-weiqht slide rail device having a sufficient riqidity.
Thus, according to the noted prior art, it is not possible to prevent the upper rail (114) from completely separating from the lower rail (112).
Of course, the foregoing problem can be solved by forming the upper and lower rails of thicker material to increase their rigidity against deformation. But, such formation of the upper and lower rails results in greater dimensions of the slide device as a whole, requiring ~284939 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 weiqht seat.
Further, in contrast to the above-mentioned prior art, there has been such a slide rail device as disclosed in the Japanese Laid-Open Utility Model Publication No.
49-106021. According to this other 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 portion of the upper rail encloses that of the lower rail. Nevertheless, it is quite possible for the upper rail to be separated from the lower one, because when a great upward pulling force is exerted on the upper rail, the curved portion of the upper rail is easily opened, resulting in the upPer rail slippinq off from the curved portion of the lower rail and becoming separated therefrom.
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 ~284939 lower rail, positively, without the necessity of forming the device of heavier weight materials.
In accomplishing this purpose accordinq to the S present invention, a lower rail is formed such as to enclose an upper rail entirely to thereby prevent the separation of the upper rail from the lower rail. In other words, the lower rail has an upper inwardly curved portion at both its 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 upward movement of the upper rail, and further that the lateral wall portion of the lower rail adjacent the upper inwardly curved portion is orientated 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 manner enclosinq the end of the upper inwardly curved portion of the lower rail, whereby, when the upper rail is moved upwardly, the ~284~39 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 the separation of both upper and lower rails is almost completely attained in comparision with the conventional slide rail devices.
Referring to Figs. 3 through 6, a preferred embodiment of slide rail device in accordance with the present invention is illustrated.
As shown, the slide rail device is designated by numeral (10), which comprises a lower rail (12) fixed on a floor of vehicle (11) and an upper rail (14) slidably secured on the lower rail (12), on which upper rail is mounted a seat (not shown).
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. In the latter embodiment, the upper rail (14) is fixed to the seat frame by inserting and fixing a suitable means such as a screw in a hole (19) perforated in the upper rail (14).
~2849~9 llereinafter, a specific description will be qiven on the basis that the upper rail (14) is formed separately from the seat frame as in Fiq. 6.
Referring now to Fig. 3, the upper rail (14) comprises a main plate (18) and an auxiliary plate (20), both of which are welded together, such that their lower portions extend downwardly in a bifurcated and symmetrical manner, and are each formed with a substantially U-shaped shoulder portion (30), a lateral wall portion (34) and an inwardly bent portion (24), all of those portions beinq integral and continuously formed with each other. In this respect, a vertical portion (36) extends continuously upwardly from the inner end portion of the shoulder portion (30), while from the outer end portion of the shoulder portion (30) the lateral wall portions (34) continuously extend downwardly defininq a protrudent bent portion (31) therebetween.
The lower rail (12) is formed by bendinq one unitary plate into a configuration enclosinq the upper rail (14), such that it comprises a pair of upper inverted U-shaped portions ~28) each terminatinq in an end (28a), a pair of inwardly inclined lateral wall portions (32), and a pair of lower outwardly curved portions (26).
1284g39 - ln -Those upper and lower rails (14) (12) are assembled together in such a manner that the lower rail (12) encloses the upper rail (14), 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 portions (30). Also the upper inverted U-shaped portions (28) are disposed above the protrudent bent portions (31) and the ends (28a) of the upper inverted U-shaped portions (28) extend into each of the substantially U-shaped shoulder portions (30). A steel ball (22) is embraced between the outwardly curved portion (26) and inwardly bent portion (24) for the purpose of facilitating the sliding movement of the upPer rail (14) along the lower rail (12). It may be that a pair of the steel balls (22) are disposed at two points in the rails (14) (12), for instance, as in Fig. 5, so that vertical and horizontal forces being applied are effectively absorbed by the balls (22) for preventing the rails (14) (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).
lZ8~9~9 It is noted that the above-mentioned upper inverted U-shaped portions (28) of the lower rail (12) and substantially ~-shaped shoulder portions (30) of the upPer rail (14) are both so formed as to extend over the entire lenqth of the rails (12) (14) in the lonqitudinal direction thereof.
As best shown in Fig. 3, the inwardly inclined lateral wall portions (32) of the lower rail (12) are obliquely oriented in a direction identical to an applying direction of an upward pullinq force (F) which is exerted upon the upper rail (14) via the seat belt (40) in a sudden deceleration case due to a collision. Experiments in this regard show that in most cases an upward pullinq force caused by a seat belt is directed obliquely at an approximate 30-deqree anqle relative to the vertical, and therefore it is perferable that the inwardly inclined lateral wall portion (32) should be oriented at 30-deqree angle in conformity with the direction of the upward pulling force (F). But, such inclination may satisfactorily fall within the angle ranqes of 25 to 35 degrees.
With the above-mentioned structure, when the upward pulling force (F) is applied to the upper rail (14), 12849~9 tending to raise it up from the lower rail (12), the protrudent bent portions (31) and shoulder portions (30) of the upper rail (14) are brouqht into abutment aqainst the upper inverted U-shaped portion (28) and its end (28a) of the lower rail (12), respectively. At this point, the upper inverted U-shaped portion (28) is subjected to a bending moment caused by the pulling force (F) and is being forcibly bent upwardly, but the inclination of the lateral wall portion (32) of lower rail (12) at an angle substantially conforming to the direction of the pulling force (F) serves to reduce the bendin~ moment, whereupon the inverted U-shaped portion (28) is not easily bent or deformed upwardly.
In this context, it is preferable that the lateral wall portion (34) of the upper rail (14) be formed substantially in parallel with the inwardly inclined lateral wall portion (32). By beinq so formed, the latter portion (32) is brought into entire contact with the former portion (34), when the bending moment is caused therein, so that the portion (34) acts as a limit against the bendinq of the portion (32), thus preventing the deformation of the upper inverted U-shpaed portion (28) in a more positive fashion.
~28~939 Further, the substantially U-shaped shoulder portion (30) is of such construction as to accommodate the end (28a) of the upper inverted U-shaped portion (28) in an embracing manner, which more effectively avoids the deformation of the portion (28). Specifically, referring to Fig. 4, as the upper rail (14) is raised upwards due to the pulling force (F), the substantially U-shaped shoulder portion (30) of the upper rail (14) is raised accordingly to press upon the end (28a) of the upper inverted U-shaped portion (28) of the lower rail (12), and then the end (28a~
becomes sandwiched and retained between the protrudent bent portion (31) and vertical portion (36) of the upper rail (14), with the result that the protrudent bent portion (31) and vertical portion (36) cooperate to firmly grip the end (28a) of the upper inverted U-shaped portion (28) at a gripping area (38) in a frictional manner. This frictional grippinq 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 in its upward movement by thus-retained end (28a) in a more assured way.
Further, while the pullinq force (F) is being applied, the shoulder portion (30) becomes contracted in its U-shaped body due to the foregoing gripping effect, which renders the shoulder portion (30) per se more rigid against any other deformation, and with such increased structural rigidity, the frictional gripping of the end (28a) at the lza4s39 areas (38) becomes so positive as not only to enhance the prevention of the end (28a) a~ainst its slipping off or from the shoulder portion (30), but also to prevent the end (28a) from deforming.
Accordingly, the end (28a) of the upper inverted U-shaped portion (28) is protected against deformation and functions to 1imit the upward movement of the upper rail (14). Also, the shoulder portion (30) of the upper rail (14) is prevented aqainst both its deformation and upward displacement. The upper rail (14), therefore, is not raised any further, and its separation from the lower rail (12) is completely eliminated.
It is especially important to note that the greater the pulling force (F) which is applied the more firmly gripped is the upper inverted U-shaped portion (28) of the lower rail (12) by the shoulder portion (30) of the upper rail (14), 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 a small-sized and light-weight slide rail device havinq such robust structure that it ensures prevention of the separation of the upper rail (14) from the lower rail (12).
1~34939 While in the embodiments havin~ been described before, the slide rail device (10) is provided on the riqht and left sides of the seat, its not always necessary 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 of the seat, however, ~ives much more reliability in preventinq 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 additions may structurally be possible without departing from the spirit of the invention. For 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 (i.e. the lower portion of main plate (18) which is shown in Fiqs. 3 and 4 as beinq disposed on the left), considering the fact that the obliquely applied pulling force (F) is mostly exerted on the lower portion of the main plate (18).
i 284939 From the above description, it is accordinqly appreciated that the slide rail device accordinq to the present invention is so riqid as to withstand a qreat bendinq moment caused by an upper pullinq 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 deformation, and particularly the upper inverted 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 (28) retains its function for limiting the upward movement of the upper rail (14), even if an extreme 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 permittinq therefore the production of a small-size and liqht-weiqht slide rail device having a sufficient riqidity.
Claims (11)
1. A slide rail device for a vehicle seat comprising a lower rail adapted to be fixed to a floor of said vehicle, an upper rail slidably fitted to said lower rail and adapted to be secured to a seat belt at one end portion thereof, wherein said lower rail includes an inwardly inclined lateral wall portion so formed that its upper part is inclined relative to its lower part in a direction inwardly of the lower rail, and further includes an upper inverted U-shaped portion formed continuously from an upper end of said inwardly inclined lateral wall portion, and wherein said upper rail includes a lateral wall portion disposed under said inwardly inclined lateral wall portion of said lower rail, and further includes a substantially U-shaped shoulder portion formed continuously from said lateral wall portion, said shoulder portion being disposed under said upper inverted U-shaped 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 substantially U-shaped shoulder portion of said upper rail is contracted to grip said upper inverted U-shaped portion of said lower rail.
2. A slide rail device according to Claim l, 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. A slide rail device according to Claim 1, 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.
4. A slide rail device according to Claim 1, 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.
5. A 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.
6. A slide rail device according to Claim 1, 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 and symmetrical manner, and are each formed with said substantially U-shaped shoulder portion, said lateral portion, and a first curved portion adapted to retain a ball means, and wherein said lower rail comprises a flat bottom portion, a pair of said inwardly inclined lateral wall portions 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. A slide rail device according to Claim 1, wherein said inwardly inclined lateral wall portion of said lower rail is inclined at an angle range from 25 degrees to 35 degrees relative to a vertical line.
8. A slide rail device according to Claim 1, wherein a seat frame is integrally fixed on said upper rail.
9. A slide rail device according to Claim 1, wherein a plurality of ball means are located between said first and second curved portions respectively of said upper and lower rails.
10. A slide rail device according to Claim 1, wherein said substantially U-shaped shoulder portion is so formed as to accommodate an end portion of said upper inverted U-shaped portion.
11. A 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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000561160A CA1284939C (en) | 1988-03-10 | 1988-03-10 | Slide rail device for vehicle seat |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000561160A CA1284939C (en) | 1988-03-10 | 1988-03-10 | Slide rail device for vehicle seat |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1284939C true CA1284939C (en) | 1991-06-18 |
Family
ID=4137623
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000561160A Expired - Lifetime CA1284939C (en) | 1988-03-10 | 1988-03-10 | Slide rail device for vehicle seat |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1284939C (en) |
-
1988
- 1988-03-10 CA CA000561160A patent/CA1284939C/en not_active Expired - Lifetime
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| Date | Code | Title | Description |
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| MKLA | Lapsed |