Protective cushion for vehicle occupant's head

[0002] 1. Field of the Invention

[0003] The present invention relates to a protective cushion for a vehicle occupant's head and, more particularly, to a cushion which can be inflated along windows of side doors in the event of a side impact or roll-over situation.

[0004] 2. Description of Related Art

[0005] One such protective cushion for a vehicle occupant's head is disclosed in International Patent Publication WO96/26087, particularly, FIG. 1 and FIG. 9 of the publication. The known cushion has a vacancy comprising a duct extending from the end at the front side of a vehicle (the front end) to the end at the rear side of the vehicle (the rear end) along the upper edge of the cushion. There are also a plurality of cells or chambers that extend downward from and communicate with the duct. Between the adjacent cells, an occupant-side sheet (hereinafter, sometimes referred to as “cabin-side sheet”) and a vehicle body-side sheet (hereinafter, sometimes referred to as “door-side sheet”) are joined.

[0006] According to the cushion disclosed in WO96/26087, the duct is formed by interweaving the cabin-side sheet and the door-side sheet. The duct thus formed is not ideal for introducing gas into the cells.

[0007] Accordingly, it is a general object of the invention to provide a protective cushion for a vehicle occupant's head that alleviates or minimizes the above described difficulties.

[0008] It is an object of the present invention to provide a protective cushion for a vehicle occupant's head that allows gas to be introduced into chambers, which are formed between sheets, in a timely manner.

[0009] It is yet another object of the present invention to provide a protective cushion for a vehicle occupant's head that is simple and cost-effective to manufacture.

[0010] A preferred embodiment of the invention intended to accomplish at least some of the foregoing objects includes a protective cushion for a vehicle occupant's head having two sheets superposed on each other and joined together to form a plurality of chambers arranged in the longitudinal direction of a vehicle.

[0011] A protective cushion for a vehicle occupant's head according to the present invention is disposed in the vicinity of a corner between a ceiling and a side surface of a vehicle cabin and is adapted to be inflated with introduced gas downwardly along the side surface. The protective cushion includes an occupant-side sheet and a body-side sheet superposed on each other and sewn together so as to form a plurality of vacant chambers between the sheets. Gas is introduced into the chambers, which are arranged in a longitudinal direction of the vehicle. The cushion also has a longitudinally extended gas passage at its upper portion. The gas passage is constructed of a cylindrical member that is provided separate from the sheets. There is at least one opening at an approximate midpoint of the gas passage that allows gas to be transferred from the cylindrical member to the chambers of the cushion.

[0012] In the protective cushion for a vehicle occupant's head, gas supplied to the cylindrical member is supplied into chambers through an end of the cylindrical member and/or openings formed in the cylindrical member. By selecting the length of the cylindrical member and/or the positions of the openings, gas can be introduced into desired chambers from desired positions.

[0013] The cylindrical member may be made of a fabric sheet or a pipe constructed from a metal or a synthetic resin. In the cases in which the cylindrical member is made from a sheet, the sheet composing the cylindrical member (hereinafter, sometimes referred to as “cylindrical member sheet”), the cabin-side sheet, and the door-side sheet are sewn together with a common thread or yarn. The sewing preferably is both for forming the cylindrical member and for sewing together the cabin-side sheet and the door-side sheet, thus reducing the man-hours required in manufacturing the cushion.

[0014] According to the present invention, the upper portion of the cushion, where the cylindrical member sheet, the cabin-side sheet, and the door-side sheet are sewn together, may be provided with small holes through which bolts or rivets are inserted to secure the cushion to the vehicle body. In this case, the force applied to the cylindrical member is transmitted directly to the vehicle body.

[0015] According to the present invention, the protective cushion may further comprise stitching in the cylindrical member downstream portion from the opening in the gas flowing direction. This stitching closes or constricts the sectional area of the gas passage in the cylindrical member. Preferably, when the gas pressure in the cylindrical member reaches or exceeds a predetermined value, the sectional area of the gas passage is enlarged as a result of the stitching breaking.

[0016] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and, together with the above general description and the following detailed description, serve to explain the principles of the invention.

[0017] FIG. 1 is a front view of a protective cushion 1 according to a first embodiment of the invention.

[0018] FIGS. 2(a) through 2(i) are sectional views taken along lines IIa—IIa through IIi—IIi of FIG. 1, respectively. FIGS. 2(j) through 2(m) are sectional views showing the cushion of FIGS. 2(c), 2(d), 2(e), and 2(h), respectively, in the inflated state.

[0019] FIG. 3 is a sectional view showing the inflated cushion 1 taken along a line III—III of FIG. 1.

[0020] FIG. 4 is a sectional view showing the inflated cushion 1 taken along a line IV—IV of FIG. 1.

[0021] FIG. 5 is a perspective view of a cylindrical member 20.

[0022] FIG. 6 is a front view of a cushion 1A according to a second embodiment of the invention.

[0023] FIG. 7(a) is a front view of a cushion 1B according to a third embodiment of the invention and FIG. 7(b) is a partial enlarged view of FIG. 7(a).

[0024] FIG. 8(a) is a perspective view of a cylindrical member 40 and FIG. 8(b) is a sectional view taken along a line VIIIb—VIIIb of FIG. 8(a).

[0025] FIG. 9 is a perspective view of a cylindrical member 40A.

[0026] Referring now to the drawings and initially to FIGS. 1-5, there will be seen a protective cushion or airbag 1 for a vehicle occupant's head according to a first embodiment of the invention.

[0027] This cushion 1 includes an occupant-side sheet or cabin-side sheet 2 and a body-side sheet or door-side sheet 3 superposed on each other and sewn together with thread (numerals 4 through 9 designate stitches) so as to define vacant chambers (hereinafter, referred to as only “chambers”) 11 through 14 between the sheets 2 and 3.

[0028] The stitch 4 extends along the lower edges of the sheets 2, 3 from the front end 1F to the rear end 1R of the cushion 1. The stitch 4 is curved into a U-like shape away from the lower edges of the sheets 2, 3 in the vicinity of the rear end 1R, thus forming an elongated chamber 10 between the stitches 5 and 4.

[0029] The stitch 5 extends along the upper edges of the sheets 2, 3 and extends downwardly from the vicinity of the front end 1F apart from the upper edge so as to meet with the stitch 4.

[0030] The stitch 6 sews sheets 2, 3 together in the vicinity of a longitudinal middle portion of the cushion 1. The main part of the stitch 6 extends in the longitudinal direction in the vertical middle of the cushion 1 and both end portions of the stitch 6 extend in the vertical direction to meet with the stitch 4. The stitch 6 substantially separates the chambers 11, 12 from each other, as shown in FIG. 1. The chambers 11, 12 communicate with each other at their upper portions.

[0031] The stitch 7 sews the sheets 2, 3 together at approximately the center of the chamber 11 to prevent the thickness of the chamber 11 (the maximum distance between the sheets 2, 3) from exceeding a predetermined range.

[0032] The stitches 8, 9 extend in the vertical direction to separate chambers 12, 13, 14 from each other. The chambers 12, 13, 14 communicate with each other at their upper portions and their lower portions.

[0033] A cylindrical member 20 is disposed between upper portions of the sheets 2, 3. The cylindrical member 20 includes a long band-like sheet 20S folded longitudinally and arranged between the upper portions of the sheets 2, 3 such that the folded portion is positioned at a lower side of the cushion 1. The sheet 20S is sewn together with the sheets 2, 3 by stitching 5 so as to form the cylindrical member 20.

[0034] The cylindrical member 20 has a rear end 21 at approximately the same position as the rear end 1R of the cushion 1 and an open front end 24 at a position above the chamber 13. An opening 22, which faces chamber 11, and an opening 23, which faces chamber 12, are formed in the cylindrical member 20 approximately midway between the stitched ends of the sheet 20S. An inflator is connected to the rear end 21 of the cylindrical member 20.

[0035] In this embodiment, the openings formed in the cylindrical member are designed so that the nearer the openings are to the inflator, the smaller the openings are, thereby achieving an equal gas supply to chambers 11 through 14.

[0036] The sheets 2, 3 and the sheet 20S of the cylindrical member 20 are each provided with a plurality of projections 30 projecting upward from the cushion 1. These projections 30 have small holes 31 formed therein. The cushion 1 is fixed to the vehicle body by inserting bolts or rivets through these small holes 31. The impact that occurs when the cylindrical member 20 is inflated is transmitted to the vehicle body through the bolts or rivets, not via the sheets 2, 3. The required strength of the sheets 2, 3 is therefore reduced.

[0037] For example, the cushion 1 is arranged such that the rear end 1R is disposed on a C pillar of the vehicle and the front end 1F is disposed on an A pillar of the vehicle. The cushion 1 is folded and arranged along a roof side rail. As described above, the inflator is connected to the rear end 21 of the cylindrical member 20.

[0038] The folded cushion 1 is covered by a cover. The cover is structured to be torn or opened into the cabin when the cushion 1 is inflated. The cover may be exclusive for the protective cushion or may be an interior garnish of the vehicle.

[0039] When the vehicle is involved in a lateral collision or roll-over, the inflator is actuated so that gas flows into the cylindrical member 20 through the rear end 21. The gas flows inside the cylindrical member 20 and partially enters into the chambers 11, 12 through the openings 22, 23 so as to inflate the chambers 11, 12. The gas partially enters into the chambers 13, 14 through the front end 24 of the cylindrical member 20 so as to inflate the chambers 13, 14. The inflated chamber 11 expands on the side of the head of an occupant sitting on a rear sheet and the inflated chambers 12, 13, 14 expand on the side of the head of an occupant sitting on a front seat.

[0040] In the cushion 1, the cylindrical member 20 is provided so that gas flows out through the openings 22, 23, and the front end 24 of the cylindrical member 20 into the chambers 11 through 14 according to a predetermined route. Thus, the chambers 11 through 14 are inflated substantially at the same time.

[0041] FIGS. 6, 7(a), 7(b) are front views of cushions 1A, 1B according to second and third embodiments, respectively. In FIGS. 6, 7(a), 7(b), cylindrical members 20A, 20B are shown in the through-vision state. Each rear portion of the cushions 1A, 1B has a horizontal upper side and an oblique lower side.

[0042] In FIG. 6, a front end 24 of the cylindrical member 20A is positioned in the chamber 14. The cylindrical member 20A is provided with an opening 25 facing the chamber 13. In FIG. 7, a front end 24 of the cylindrical member 20B is positioned at edges of the sheets 2, 3. The cylindrical member 20B is provided with openings 25, 26 facing the chambers 13, 14, respectively. The remaining structure of the cushions shown in FIGS. 6, 7(a), 7(b) are the same as those of the cushion shown in FIGS. 1 through 5.

[0043] In the cushion 1A, gas from the inflator flows out through the openings 22, 23, 25 and the front end 24 of the cylindrical member so as to inflate the chambers 11 through 14. In the cushion 1B, gas from the inflator flows out through the openings 22, 23, 25, 26 so as to inflate the chambers 11 through 14. In both of the cushions 1A, 1B, gas is supplied to the chambers 11 through 14 according to a predetermined route. Also in both of the cushions 1A, 1B, the chambers 11 through 14 are inflated at substantially the same time.

[0044] FIGS. 8(a), 8(b), 9 show cylindrical members 40, 40A that allow the inflation of the chambers 11 through 14 with some time lags. Each cylindrical member 40, 40A comprises a sheet 40S which is folded longitudinally into two half-sheets. An upper portion of the folded sheet 40S is sewn together with the sheets 2, 3 by the stitch 5 so as to form the cylindrical member 40, 40A. Each cylindrical member 40, 40A has an opening 41, through which gas flows out, at an approximate longitudinal middle of the cylindrical member. Each cylindrical member 40, 40A is provided with stitches 42, i.e., a constricting or closing element, which can be broken, located downstream from the opening 41. In FIG. 8(a), the stitches 42 extend from the upper edge to the lower edge of the cylindrical member 40, entirely closing the passage inside the cylindrical member 40. On the other hand, in the cylindrical member 40A, the stitches 42 close only an upper half of the passage inside the cylindrical member 40A.

[0045] As gas is introduced into the cylindrical member 40, 40A, the gas flows out through the opening 41. When the gas pressure at the upstream side of the stitches 42 exceeds a predetermined value, and the subsequent load on the stitches 42 causes the tension on the stitches 42 to be larger than the tensile strength of the yarn or thread, the yarn of the stitches 42 is broken so that a large amount of gas flows downstream from the stitches 42.

[0046] As mentioned above, the stitches 42 can achieve the staggered inflation among the chambers. The stitches 42 can be structured so that a larger amount of gas is introduced into a larger chamber while a smaller amount of gas is introduced into a smaller chamber.

[0047] The stitches 42 closing a part of the passage inside the cylindrical member as shown in FIG. 9 may not be broken. In this case, the stitches 42 function as a constriction in the passage of the cylindrical member until the termination of inflation of the cushion.

[0048] Though the cylindrical member is made of a sheet in the above embodiments, the cylindrical member may be a pipe made of metal or a synthetic resin. When made of a synthetic resin, the pipe or tube could be flexible; it could be a rubber hose. The term cylindrical includes a member that is elliptical or substantially elliptical in cross section.

[0049] Though the preferred embodiment of the closing or constricting element is stitching 42, the closing or constricting element may also be an adhesive.

[0050] Though the cushion has the length from the A pillar to the C pillar in the above embodiments, the cushion may extend from the A pillar to the B pillar, or, from the B pillar to the C pillar. The gas inlet of the cylindrical member may be positioned at the front end thereof or at a middle portion of the cylindrical member.

[0051] As described above, according to the present invention, gas can be supplied to chambers of a protective cushion for a vehicle occupant's head at the same time or with desired time lags among the chambers.

[0052] Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects, therefore, is not limited to the specific details and representative devices described herein.

[0053] The priority document, Japanese Patent Application H10-234417 filed Aug. 20, 1998, is hereby incorporated by reference.