Inflatable belt

Abstract: An inflatable belt has an envelope-shaped or elongated belt body, which is folded in a long band-like configuration, and a cover enclosing the belt body. One end of the belt body 11 is connected to a tongue 15. The cover preferably is made from a stretchable knitted fabric. There is a cushion layer between the belt body 11 and the cover 12. The outer surface of the cushion layer 13 is processed by low frictional treatment such as fluororesin coating. A low-friction film or tape may also be laid between the cushion layer and the cover. Thus, the inflatable belt feels softer when it contacts the occupant or when the occupant touches the belt.

Description: Background of the Invention Field of the Invention The present invention relates to a seat belt for protecting a vehicle occupant during a vehicle collision and, more particularly, to an inflatable belt which is capable of being inflated with gas, according to the features of claim 1. Description of the Related Art An inflatable belt device of this type is disclosed in Japanese Unexamined Patent Publication H05-85301 and is shown in Figures 6(a) and 6(b). This passenger protective device 1 includes a shoulder belt 2 extending diagonally from the right side to the left side of a passenger, a lap belt 3 extending from the right side to the left side of the passenger, a buckle 4 fixed to, for example, a vehicle floor, a tongue 5 to be inserted into and engaged with the buckle 4 when the passenger wears the belt, and an intermediate guide 6 for guiding the shoulder belt 2. The shoulder belt 2 includes a normal webbing 2a, which is the same as a typical conventional seat belt, and an inflatable belt 2b connected to an end of the webbing 2a. The webbing 2a is slidably hung in the intermediate guide 6. The other end of the webbing 2a is connected to a shoulder belt retractor 7 with an emergency locking mechanism (ELR), which is fixed to the vehicle body. The webbing 2a is arranged such that it is wound into the shoulder belt retractor 7. The inflatable belt 2b is positioned so that it contacts the passenger and is connected to the tongue 5 at an end opposite to the end connected to the webbing 2a. The lap belt 3 is composed of a normal webbing, which is the same as a typical conventional seat belt, having one end is connected to the tongue 5 and the other end connected to a lap belt retractor 8 (ELR), which is fixed to the vehicle body. A gas generator 9 is connected to the buckle 4. The gas generator 9 is actuated in emergency situations, e.g., vehicle collisions, to generate high-pressure gas. The tongue 5 and the buckle 4 are each provided with passages for introducing gas from the gas generator 9 into the inflatable belt 2b. The inflatable belt 2b of the shoulder belt 2 includes a belt body 2c formed in an envelope-like shape and a cover 2d. The belt body 2c is folded, shown in solid lines in Figure 6(b), and then covered by the cover 2d. The ends of the cover 2d are then connected to each other by stitching 2e so that the inflatable belt 2b is maintained in a band-like configuration. The stitching 2e of the cover 2d is easily torn by the force of the shoulder belt 2 expanding when the gas generator 9 is actuated so that the inflatable belt 2b is deployed, shown by a two-dot chain line in Figure 6(b). The belt body 2c is made of, for example, rubber coated fabric and the cover 2d is made of a flexible knit with excellent stretchability. WO 97/23367 A discloses an inflatable belt portion which is attached to a lap belt portion by stitching. A cover envelopes the inflatable belt portion and a stiffener is disposed within the cover against the inflatable belt portion to prevent the inflatable belt portion from twisting so that is in a flattened configuration prior to inflation. FR 2,694,529 discloses an inflatable seat belt system with a tube, which is made of an elastic material. The tube is inserted in a webbing and a cover is covering the webbing. The closest prior art document US 5,466,002 discloses an inflatable seat belt apparatus comprising an inner belt which is inserted in a flat condition into a tube. This tube is accommodated in a cylindrical knitted textile member of a flat type which is knitted in a size slightly larger from the tube. The conventional inflatable belt feels very stiff when touched by a vehicle occupant. Summary of the Invention Accordingly, it is an object of the invention to provide an inflatable belt having an improved feeling when it is touched by a vehicle occupant. A preferred embodiment of the includes a belt body into which a gas is introduced; a cover enclosing the belt body; and a cushion layer between the cover and the belt body; an outer surface of the cushion layer has a low coefficient of friction. Additional objects and advantages of the invention will be set forth in the following description of the preferred embodiments and, in part, will be obvious from the description or through practicing the invention. The objects and advantages may be realized through the instrumentalities and combinations particularly pointed out in the appended claims. Brief Description of the Drawings 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. Figure 1(a) is a general view of one embodiment of the invention; Figure 1(b) is a perspective view, partly in section, of that same embodiment. Figure 2(a) is a plan view of a portion around the connection between a shoulder belt and an inflatable belt; Figure 2(b) is a plan view of an envelope-shaped belt body; Figures 2(c), 2(d), and 2(e) are sectional views taken along lines C-C, D-D, and E-E of Figure 2(a), respectively. Figure 3(a) is a plan view of a shoulder belt in a state where the inflatable belt is inflated; Figure 3(b) is a plan view of the belt body in the inflated state; and Figures 3(c) and 3(d) are sectional views taken along lines C-C and D-D in Figure 3(a), respectively. Figures 4(a) and 4(b) are views for explaining the knit structure of a cover of the inflatable belt. Figure 5 is a perspective sectional view of another embodiment of the inflatable belt according to the invention. Figures 6(a) and 6(b) are views illustrating the structure of a conventional inflatable belt. Detailed Description of the Preferred Embodiments Referring now to the Figures and initially to Figures 1(a) and 1(b), there will be seen an inflatable belt 10 according to one embodiment of the invention. The inflatable belt 10 includes an envelope-shaped or elongated belt body 11 folded in a long band-like configuration, a cover 12, which is preferably a knit cover, enclosing the belt body 11, and a cushion layer 13 between the belt body 11 and the cover 12. The cushion layer 13, preferably, is made from a soft material such as, for example, polyurethane or PVC. The thickness of the cushion layer 13 is preferably from 0.5 mm to 5 mm, particularly from 1 mm to 3 mm. The outer surface of the cushion layer 13, which contacts the cover 12, is processed by low frictional treatment. Examples of low frictional treatment include fluororesin coating, PVC dip coating, and the like. As shown in Figure 1(a), one end of the belt body 11 is connected to a tongue 15, which includes a tongue plate 16 and a cylindrical socket 17 for introducing gas into the inflatable belt 10. Similar to the conventional seat belt system of Figures 6(a) and 6(b), the tongue plate 16 is inserted into a tongue insertion slot of a buckle and is latched by a latching mechanism. The latching is canceled by pressing a press button on the buckle. The socket 17 is fitted to a plug of the buckle so that gas from a gas generator or inflator is introduced into the belt body 11 through the plug and the socket 17. The inflatable belt 10 is a part of a shoulder belt and the other end of the belt body 11 is connected, preferably via sewing or the like, to an end of a webbing 18. The other end of the webbing 18 is fixed to a take-up shaft or reel shaft of a retractor for the shoulder belt. An end of a lap belt is secured to the tongue 15 and the other end is fixed to a take-up shaft of a retractor for the lap belt. The belt body 11 is shaped such that parts corresponding to the chest and abdomen of an occupant are wider than the other parts of the inflatable belt. As shown in Figure 2(a), the inflatable belt 10 has a long band-like configuration and has a cover 12. As shown in Figure 2(b), the wider part is folded to make the belt body 11 in the long band-like configuration. The belt body 11 is made from a fabric that is preferably coated with a soft rubber such as silicone rubber. The fabric is then sewn to form the belt body 11 (the sewing results in a seam 11a). As shown in Figures 2(c)-2(e), the belt body may be folded in a number of different manners. A second embodiment of an inflatable belt 10A is shown in Figure 5. The inflatable belt 10A includes tapes 14 that are preferably made from a material having a low friction coefficient and that are placed between the outer surface of the cushion layer 13 and the inner surface of the cover 12. Examples of the tapes include fluororesin tapes and the like. Though the tapes 14 intervene in Figure 5, the cushion layer 13 may be entirely coated with a film of a low frictional material such as fluororesin. In this case, it is preferable that the coating film be provided with a tear line, e.g., a perforation or a slit, so that the film tears along the tear line when the belt body 11 is inflated. The cover 12 is supplely stretchable in its width direction, but is hard to stretch in the longitudinal direction of the belt. Figures 4(a) and 4(b) are two examples of methods for knitting the preferable knit cover. Figure 4(a) shows normal warp-knitted stitches and Figure 4(b) shows stitches that are warp-knitted, but have additional yarns inserted to increase the strength the strength of the cover fabric while maintaining its thinness. The cover 12 is hard to stretch in the longitudinal direction (withdrawing direction) of the belt because it is preferably processed by heating and drawing. The cover 12, preferably, is cylindrically shaped and has one end, together with the belt body 11, connected to the tongue 15, while the other end, together with the belt body 11, is connected to the webbing 18, by sewing or the like. The cover 12 is connected to both the webbing 18 and the tongue 15 so as to withstand a tension load that is applied to the inflatable belt. As shown in Figures 3(a)-3(d), the knit cover 12 is hard to stretch in the longitudinal direction of the belt because it is processed by heating and drawing. The interstices of the knit cover 12 stretch in the width direction when the belt body 11 is inflated. As a result, the knit cover 12 shrinks in the longitudinal direction so that the length of the inflatable belt 10 or 10A is shortened. The inflatable belt 10, 10A structured as mentioned above will be used for protecting an occupant in the same manner as a normal seat belt when the tongue 15 is engaged with the buckle. The inflatable belt 10, 10A has a cushion layer 13 between the cover 12 and the belt body 11, thereby feeling softer to the occupant. The friction between the cushion layer 13 and the cover 12 should be small enough such that the inflatable belt 10. 10A may bend in a supple fashion. This bending allows the inflatable belt 10, 10A to fit the body contours of the occupant very easily. When the gas generator is actuated due to a vehicle collision or roll-over, gas is introduced into the belt body 11 so that the belt body 11 is inflated. When the inflatable body 11 is inflated, the cushion layer 13 and the cover 12 are also inflated. Alternatively, the cushion layer 13 may be provided with a tear line comprising a perforation or a slit so that the cushion layer 13 tears along the tear line when the belt body 11 is inflated. As described in the above, the inflatable belt of the present invention has an improved feeling when touched by the occupant, thereby providing improved comfort to the occupant. Further according to the present invention, the friction between the cushion layer and the cover can be reduced, thereby facilitating the bending of the inflatable belt. An inflatable belt of the present invention protects an occupant in a vehicle seat and is inflated when a gas is introduced inside. The inflatable belt includes an envelope-shaped or elongated belt body into which gas is introduced, a stretchable cover enclosing the belt body, and a cushion layer between the cover and the belt body. The inflatable belt according to the invention, because of the cushion layer laid between the belt body and the cover, feels soft when it contacts the occupant or when the occupant touches the belt. In the present invention, it is preferable that the frictional resistance between the cushion layer and the cover be reduced so that bending of the inflatable belt is facilitated. To reduce the frictional resistance between the cushion layer and the cover, the surface of the cushion layer is preferably processed by a low frictional treatment. A low-friction film or tape may also be laid between the cushion layer and the cover. Additional modifications and advantages may readily appear to one skilled in the art.

Claims: An inflatable belt (10) for protecting an occupant in a vehicle seat, the inflatable belt (10) comprising: a belt body (11) into which a gas is introduced; a cover (12) enclosing the belt body (11); and a cushion layer (13) between the cover and the belt body (11), characterized in that an outer surface of the cushion layer (13) has a low-coefficient of friction and that a tape (14) is arranged between said cushion layer (13) and said cover (12). An inflatable belt as claimed in claim 1, further comprising a film between the cushion layer (13) and the cover (12). An inflatable belt as claimed in claim 2, wherein the film has a low coefficient of friction. An inflatable belt as claimed in claim 3, wherein the tape (14) has a low coefficient of friction. An inflatable belt as claimed in claim 1, wherein the cover (12) includes a knit fabric. An inflatable belt as claimed in claim 1, wherein a thickness of the cushion layer (13) is between 0,5 mm and 5 mm. An inflatable belts as claimed in claim 1, wherein a thickness of the cushion layer (13) is between 1 mm and 3 mm. An inflatable belts as claimed in claim 1, wherein an outer surface of the cushion layer (13) is coated with a fluororesin coating. An inflatable belts as claimed in claim 8, wherein the fluororesin coating includes a tear line. An inflatable belts as claimed in claim 1, wherein the outer surface of the cushion layer (13) is coated with a PVC dip coating. An inflatable belts as claimed in claim 1, wherein the PVC dip coating includes a tear line. An inflatable belts as claimed in claim 1, wherein the belt body (11) is coated with a soft rubber. An inflatable belts as claimed in claim 1, wherein the belt body (11) is coated with a silicone rubber. An inflatable belts as claimed in claim 1, wherein the cover (12) is hard to stretch in a longitudinal direction. A safety belt system comprising: a webbing (18): an inflatable belt (10) connected at one end to the webbing (18), the inflatable belt (10) including a belt body (11) into which a gas is introduced; a cover (12) enclosing the belt body (11); and a cushion layer (13) between the cover (12) and the belt body (11); a tongue (15) having a duct communicating with the gas inlet of the inflatable belt (10); and a gas generator communicating with the duct of the tongue (13) for supplying a gas into the inflatable belt (10) to inflate the inflatable belt (10), characterized in that an outer surface of the cushion layer (13) has a low-coefficient of friction and that a tape (14) is arranged between said cushion layer (13) and said cover (12).

Inventors: TAKEUCHI YOSHIYUKI, TAKEUCHI, YOSHIYUKI
Applicants: TAKATA CORP, TAKATA CORPORATION
Application year: 1999
Main classification: B60R21
IPC codes: B60R21, B60R22