WO1997006983A1

WO1997006983A1 - Inflatable tubular restraint system

Info

Publication number: WO1997006983A1
Application number: PCT/US1995/010695
Authority: WO
Inventors: Gershon Yaniv; David J. Romeo; Dirk J. Hardtmann
Original assignee: Simula Inc.
Priority date: 1995-08-16
Filing date: 1995-08-16
Publication date: 1997-02-27

Abstract

The present invention is a safety belt system (110) whose lap belt member (102) inflates upon impact to protect the occupants of a vehicle such as an automobile. The inflating component of the present invention is a braided tube (101) linked to a gas generator (109). When an impact is detected, the gas generator (109) is ignited, inflating the braided tube (101). As the braided tube (101) inflates, the diameter of the tube (101) increases and its length decreases. The contracting tube (101) pretensions the safety belt system (110) by pulling any slack out of the lap belt (102) and the connecting shoulder belt (103). The inflated structure restricts the forward motion of an occupant and distributes crash loads over larger pelvic area to reduce both primary and secondary injuries.

Description

nTElATABLE TUBULAR RESTRAINT SYSTEM

This application is a continuation-in-part of U.S. Patent Application Serial No. 08/019,655. filed on February 19, 1993, to be issued as U.S. Patent No. 5,322,322, which is incorporated by reference herein.

BACKGROUND

Field of the Invention.

The present invention relates to safety apparatus for restraining the body of an occupant in a vehicle to reduce the extent and severity of injuries during a crash. More specifically, the present invention relates to safety belts which reduce the extent and severity of both primary and secondary injuries to vehicle occupants.

Background of the Invention.

Conventional safety belts are designed to protect the occupants of vehicles such as automobiles, airplanes, helicopters, trains, trucks, boats and ships from primary injuries during an accident. Primary injuries are injuries caused by the initial impact of the occupants against the interior of the vehicle. However, the protection provided by conventional safety belts against primary injuries may sometimes be inadequate. For example, slack safety belts may lead to unnecessarily serious primary injuries. More¬ over, the safety belts themselves may often be responsible for secondary injuries, e.g. , if the load from the safety U.S. Patent No. 5,282,648 which is incorporated by reference herein, discloses an inflatable body and head restraint system (shown in Figures la-Id) , wherein inflat¬ able bladders are attached to the shoulder straps of a harness restraint. The bladders are stowed partially underneath and partially on top of harness straps. This configuration provides stability and prevents the bladders from rolling out of position during inflation. During a crash, the bladders inflate to protect the upper body, primarily the head and neck of the occupant.

U.S. Pat Nos. 3,948,541 and 3,905,615 to Schulman, disclose another inflatable body and head restraint system, wherein a bladder is securely affixed to shoulder straps and a lap belt. The bladder has chin, chest, and pelvic bags. Upon impact, the bladder automatically inflates to cushion the pelvic areas and to prevent forward rotation of the head. However, as shown in Figures 2a-2c, upon inflation the bladder tends to roll out from its position under the shoulder straps. Also, because the bladders are constricted by the harness, portions of the bladder are subjected high pressures, which can lead to splitting of the bladder.

Simple inflatable body restraints are also disclosed in U.S. Patent Nos. 3,682,498 to . Rutzki and 4,348,037 to B. Law et al. These patents disclose inflatable protective devices that are located in or under the safety harnesses to which they are attached. These inflatable body restraints are subject to roll-out and seam or web splitting problems.

U.S. Patent No. 3,841,654 to Lewis discloses a vehicle safety system which comprises a seat belt having an inflatable section. When a collision is detected, the inflatable section of the safety belt is inflated to protect the person wearing the seat belt.

SUMMARY OF THE PRESENT INVENTIQN

The present invention is a safety belt system having an inflatable lap belt, connected to a crash sensor, that shortens as it inflates. The present invention is intended to replace conventional automotive safety belts. It can also be used in other types of vehicles, such as boats, trains, helicopters, trucks, ships and airplanes.

The lap belt portion of the safety belt system comprises a braided tube of continuous high-strength fibers. In order to provide superior gas retention, the braided tube may additionally contain an inner bladder. As the braided tube inflates, the diameter of the tube increases while its length decreases significantly.

In the uninflated state, the braided tube assumes a flat woven belt configuration and acts as a conventional seat belt member. However, as the braided tube inflates, the decreasing tube length acts as a pretensioning device by drawing any slack out of the lap belt and the connecting shoulder strap member. The shortened length of the braided tube also helps to further restrict subsequent occupant motion. The inflated braided tube additionally provides a much larger restraint surface area for the lower body, which helps to disperse belt load forces acting on the pelvic region.

When the inflated braided tube is loaded by the occupant's pelvis, it flattens slightly. This flattening increases the contact area between the pelvis and the braided tube, thus further reducing the pressure on the pelvis. This is opposite to the performance of a conven¬ tional lap belt, which tends to roll up its edges under loading, thus decreasing the contact area and increasing the pelvic pressure and the injury hazard.

The inflatable braided tube is connected to a gas generator which is in turn connected to a crash sensor. When the crash sensor detects an impact, it sends a signal to a gas generator. The generator propellant ignites, inflating the braided tube. The gas generator can be integrated within the seat base for sound daπping purposes.

The primary function of the present invention is to prevent or reduce the severity of primary and secondary injuries suffered by a vehicle occupant by pretensioning the restraint system, further restricting the motion of the occupant's body, and by distributing the belt forces over a larger pelvic surface area.

Accordingly, it is an object of the present inven¬ tion to provide a protective safety belt system that inflates on impact to protect the occupant of a vehicle. tion to provide a protective safety belt system that inflates on impact to protect the occupant of a vehicle.

It is another object of the present invention to provide protective apparatus that restricts occupant motion during a crash.

It is another object of the present invention to provide an inflatable braided tube member that shortens as it inflates to pretension the restraint system.

It is another object of the present invention to provide an inflatable braided tube that distributes crash loads over larger pelvic area, thus minimizing pain and injury.

It is another object of the present invention to provide an inflatable braided tube that is not subject to roll-out or seam splitting problems.

These and other objects of the present invention are described in greater detail in the detailed description, the appended drawings, and the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures la-Id are schematics showing the deploy¬ ment sequence of prior art air bags that are affixed to the strap(s) of a harness restraint.

Figures 2a-2c are schematics showing the deploy¬ ment sequence of prior art harness-mounted air bags that roll out from under harness straps.

Figure 3a shows the present invention in the uninflated configuration.

Figure 3b shows the present invention in the inflated configuration.

Figure 3c shows the present invention in the uninflated configuration installed with respect to the driver-side seat of a typical automobile.

Figure 4a shows the braided tube of the present invention in the uninflated state.

Figure 4b shows the braided tube of the present invention in the inflated state.

Figure 5a is a cross-sectional view of a first preferred internal embodiment of the braided tube of the present invention having an inner bladder.

Figure 5b is a cross-sectional view of a second preferred internal embodiment of the braided tube of the present invention having a seamed inner bladder.

Figure 5c is a cross-sectional view of a third preferred internal embodiment of the braided tube of the present invention having a seamless inner bladder.

Figure 6 shows an enlarged, cross-sectional side view of a preferred method of sealing and finishing the ends of the braided tube of the present invention.

T-T-rrATT.τT. DESCRIPTION OF THE INVENTION

The preferred embodiment of the present invention is shown in the uninflated and inflated configurations in Figures 3a and 3b, respectively. Figure 3c shows the present invention installed with respect to a typical driver-side automobile seat 121. The safety belt system 110 of the present invention comprises lap belt 102, shoulder strap 103, buckle assembly 105, anchors 106 and 117, gas generator 109, and sensor assembly 123.

Lap belt 102 and shoulder strap 103 form one continuous strap. Lap belt 102 is designed to restrict the forward motion of a seated occupant at the pelvis. It comprises braided tube 101 connected, preferably by stitching, to short strap 104 at one end, and to shoulder strap 103 at the other end. The opposite end of short strap

104 is connected to lap belt anchor 106 that pivotally mounts lap belt 102 to the base portion of seat 121 (as shown in Figure 4c) or to the floor structure on the door- side of seat 121. Gas generator 109 is preferably mounted inside the seat base to protect it from impacts and to dampen the noise it produces when activated. Thermally resistant tubing 116 provides a fluid path from gas generator 109 to braided tube 101.

The other end of lap belt 102 loops through the male portion of buckle assembly 105, so that the length of the lap belt 102 can be adjusted to accommodate a wide range of seated occupants. The female portion of buckle assembly

105 is attached to buckle strap 107. Buckle strap 107 is mounted to the base of seat 121, or to the floor structure on the side of seat 121 that is furthest from the door, by anchor 117. The female and male portions of buckle assembly 105 fasten together, thus securing safety belt system 110 around the pelvic region of an occupant in a manner similar to that used by conventional three point safety belt systems.

As shown in Figure 3c, shoulder strap 103 extends diagonally from the occupant's hip to behind and above the occupant's shoulder. The upper end of shoulder strap 103 loops through a D-ring 108 that is mounted to the vehicle in the roof rail or the upper B-pillar area. The strap then is mounted to the vehicle by a conventional inertia reel device (not shown) . Shoulder strap 103, buckle strap 107, and short strap 104 are formed from conventional webbing material such as nylon, dacron, or polyester.

The key component of lap belt 102 is inflatable braided tube 101, which is similar to the braided tubes disclosed in U.S. Patent 5,322,322, and in .Application Serial No. 08/181,768, filed January 21, 1994, which are incorporated by reference herein. Braided tube 101 is shown in detail in Figures 4a and 4b. Braided tube 101 is made of continuous fibers that may or may not be impregnated with elastomeric material, such as silicone rubber or urethane. Typical fiber materials include aramid, nylon, dacron and other polyester fibers. In the uninflated state, shown in Figure 4a, braided tube 101 is elongated with its woven fibers forming obtuse and acute angles at the fiber crossing points 111. For the sake of convenience and clarity, the angles which are acute in Figure 4a (which would be bisected by a line parallel to the longitudinal axis of the braided tube) will be termed the longitudinal angles. The angles which are obtuse in Figure 4a (which would be bisected by a line parallel to the circumference of the braided tube) will be termed the circumferential angles. Angle 201 in Figure 4a is a longitudinal angle, and angle 202 in Figure 4a is a circumferential angle.

The fibers in the braided tube thus form clockwise and counterclockwise spirals both prior to inflation, and subsequent to inflation. Prior to inflation, the spirals are stretched-out longitudinally, and have a relatively small diameter. Subsequent to inflation, the spirals are closer together longitudinally, and have a relatively larger diameter. This occurs because, when the tube is inflated, the tube fibers seek an orientation that allows a larger volume within the tube.

Figure 4b shows that as it inflates, braided tube 101 shortens in length, while its diameter increases. The braid fibers ultimately seek an orientation in which the longitudinal angles increase substantially as the tube diameter increases. As the tube diameter increases, the tube length decreases. If the tube were unconstrained, its length would decrease by as much as 50%. The preferred range for unconstrained decrease of the tube length is 10- 50%.

The uninflated braided tube typically has a longitudinal angle of 30° to 70°. Because the fibers will naturally seek a longitudinal angle of 110°, the optimal angle after inflation is approximately 100°, although the useful range for the longitudinal angle after inflation is from 50° (when the uninflated longitudinal angle is low) up to 110°.

Figure 3a shows safety belt system 110 of the present invention in the uninflated state in which braided tube 101 assumes a flat woven belt configuration and the system acts as a conventional 3-point restraint. The uninflated braided tube forms a high-strength belt that has the same width (approximately 2 inches) as the conventional webbing material of shoulder strap 103.

When a collision occurs, crash sensor 123 sends a signal to the initiator in gas generator 109. The initiator then ignites the generator propellant, thus producing a gas that inflates braided tube 101. As gas flows into the chamber of braided tube 101, the internal pressure causes the tube diameter to increase and the tube length to decrease. However, lap belt 102 is constrained on the door side by lap belt anchor 106, which prevents the door-end of braided tube 101 from moving. Thus braided tube 101 contracts toward the door, pulling any slack out of lap belt

102 and contiguous shoulder strap 103. Since shoulder strap

103 is also secured at the upper end (by an inertia reel device) , lap belt 102 and shoulder strap 103 are pulled into a taut configuration. The occupant is thus provided with a pretensioned safety belt, which restricts the forward motion of the occupant and reduces primary injuries.

Braided tube 101 is not stowed under any belt member. This design allows the tube to inflate evenly without experiencing roll-out problems. Seam splitting problems common to inflating bladders are also avoided because braided tube 101 is a seamless structure.

When fully inflated as shown in Figures 3b and 3c, braided tube has a diameter of approximately 2 to 4 inches and a relative internal pressure of approximately 1 to 4 bars (2 to 5 bars absolute pressure) . Inflated braided tube 101 helps to further restrict occupant motion. Unlike conventional 3-point safety belt systems, the present invention additionally helps lessen or prevent secondary belt-inflicted injuries by providing a substantially larger restraint surface area for the lower body, which helps to disperse belt load forces acting on the pelvis.

The gas generator used in the invention are preferably similar to those currently used in automotive air bags in Europe. Gas generators preferred for this invention must fully inflate braided tube 101 to relative pressures of approximately 1.5 bars (2.5 bars absolute) within 10 to 15 milliseconds.

The braided tube 101 may contain an inner bladder member, in order to provide superior gas retention. Figures 5a-5c show cross-sectional views of three preferred internal embodiments of braided tube 101 of the present invention. As shown in Figure 5a, the first preferred internal embodi- ment of braided tube 101 includes an inner bladder 112 that is made of a gas-retentive fabric or material, such as a material or a fabric singly or doubly coated with silicone, neoprene or urethane. Inner bladder 112 can be attached to the inner surface of braided tube 101 by adhesive bonding in several places. Portions of inner bladder 112 may be reinforced with one or more layers of material, such as elastomeric material or fabric, to provide additional thermal resistance to the gas generator's output flow. Inner bladder 112 is fluidly connected to gas generator 109 (shown in Figures 3a and 3b) by thermally resistant tubing 116 (shown in Figures 3a-3c) . The inflation of braided tube 101 is accomplished by the full or partial inflation of inner bladder 112. Specifically the generated gas inflates inner bladder 112, thus causing an internal pressure that inflates braided tube 101. Due to diameter restrictions imposed by the high-strength fibers of braided tube 101, inner bladder 112 may or may not be permitted to fully inflate. Inner bladder 25 may or may not include a seam running the length of bladder 112.

Figure 5b shows a second preferred intemal embodiment of braided tube 101 of the present invention. This internal embodiment is similar to the first preferred internal embodiment, but uses a seamed inner bladder 113. Seamed inner bladder 112 is constructed of one or more layers of gas-retentive elastomeric material, preferably silicone rubber or urethane, with a bonded seam 114 running the length of the bladder. Unlike the inner bladder of the first embodiment, seamed inner bladder 113 is uniformly bonded to the inner surface of braided tube 101 by adhesive (not shown) .

A third preferred internal embodiment of braided tube 101 of the present invention is shown in Figure 5c. This internal embodiment is similar to the second preferred internal embodiment, but uses a seamless inner bladder 115 instead of a bladder with a seam.

The preferred method for sealing and finishing the ends of braided tube 101 of the present invention is shown in Figure 6. Figure 6 shows the side view of an enlarged cross-section of an end portion of braided tube 101. Braided tube 101 is shown in its inflated state. Figure 6 shows inner bladder 115 of the third preferred internal embodiment. However, inner bladders 112 or 113 (shown in Figures 5a and 5b) can be used instead of inner bladder 115.

As shown in Figure 6, the ends of internal bladder 115 are turned inward and flattened, essentially forming an upper and lower layer that are sealed together by adhesive 117. The ends of braided tube 101 are brought together and flattened, essentially forming an upper and lower surface which are bounded together by stitching 120. The end of braided tube 101 may be wrapped with one or more layers of reinforcing fabric tape 119 to prevent fraying. The wrapped tube end is then stitched to either short strap 103 or to shoulder strap 104 (depending upon which end of the tube is presented) .

The preferred closure and finishing method shown in Figure 5 helps braided tube 101 remain air-tight and provides adeguate load transmission between braided tube 101, the connecting belt portions of restraint system 110, and the vehicle structure.

The foregoing disclosure of the preferred embodi¬ ments of the present invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. In particular, the present inven¬ tion may be used in land, sea or air vehicles, as well as in automobiles. For example the present invention may be used in trains, trucks, buses, vans, boats, ships, helicopters and airplanes. Many variations and modifications of the embodiments described herein will be obvious to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.

Claims

WHAT WE CLAIM IS :

1. A safety system for protecting the occupants of a vehicle comprising:

(a) an inflatable braided tube of continuous high- strength fibers having a door end and an inner end;

(b) a first short strap connecting the door end of the braided tube to a first anchor;

(c) a shoulder strap having an inner end connected to the inner end of the braided tube, the inner end of said shoulder strap looping through a first part of a buckle assembly, said shoulder strap having a door end mounted to the vehicle or seat;

(d) a second part of a buckle assembly, said second part of the buckle assembly being releasably connectable to the first part of the buckle assembly;

(e) a second short strap connecting the second part of the buckle assembly to a second anchor; and

(f) a gas generator fluidly connected to the braided tube, wherein the continuous high-strength fibers form spirals prior to inflation, and upon inflation by gas generated by the gas generator, the inflatable braided tube increases its diameter and decreases its length.

2. The safety system of claim 1, wherein, prior to inflation, the continuous fibers form longitudinal angles of 30° to 70°, and, after inflation, the continuous fibers form longitudinal angles of 50° to 110° such that the inflatable braided tube decreases its length by 10%-50%.

3. The safety system of claim 2, wherein the first anchor is pivotally mountable to vehicle or seat.

4. The safety system of claim 2, wherein the inflatable braided tube comprises an inner bladder.

5. The safety system of claim 4, wherein the inner bladder is attached to the inner surface of the inflatable braided tube by an adhesive.

6. The safety system of claim 4, wherein the inner bladder is fluidly connected to the gas generator by thermally resistant tubing.

7. The safety system of claim 4, wherein the inner bladder is a seamed bladder.

8. The safety system of claim 7, wherein the inner bladder is uniformly bonded to the inner surface of the inflatable braided tube.

9. The safety system of claim 1, wherein the longitudinal angle after inflation is approximately 100°.

10. The safety system of claim 1, further comprising:

(g) a crash sensor, electrically connected to the gas generator; and

(h) means for igniting the gas generator in response to a signal from the crash sensor.

11. A safety belt comprising:

(a) a lap belt comprising an inflatable braided tube having a door end and an inner end, and a first short strap attached to the door end of the inflatable braided tube;

(b) a shoulder belt looped through a first part of a buckle assembly, and attached to the inner end of the inflatable inner tube;

(c) a second part of a buckle assembly, said second part of the buckle assembly being releasably connectable to the first part of the buckle assembly;

(d) a second short strap attached to the second part of the buckle assembly; and

(e) means for fluidly connecting the inflatable braided tube to a gas generator, wherein the inflatable braided tube comprises continuous fibers forming spirals, the continuous fibers crossing each other at fiber crossing points, such that when the braided tube is in its uninflated state, the continuous fibers form acute longitudinal angles at angles of 30° to 70° at the fiber crossing points, and as the braided tube is inflated, the longitudinal angles increase to 50° to 110°, causing the length of the inflatable braided tube to decrease by at least 10%.

12. The safety belt of claim 11, wherein, upon inflation, the longitudinal angles increase to approximately 100°, and the inflatable braided tube decreases its length by 10% to 50%.

13. The safety belt system of claim 11, wherein the uninflated width of the inflatable braided tube is approximately two inches.

14. The safety belt of claim 11, wherein the inflatable braided tube can be fully inflated by filling the braided tube with gas to a relative internal pressure of approximately 1.5 bars.

15. The safety belt of claim 11, wherein the inflatable braided tube comprises an inner bladder.

16. The safety belt of claim 15, wherein the inner bladder is attached to the inner surface of the inflatable braided tube by an adhesive.

17. The safety belt of claim 15, also comprising means for fluidly connecting the inner bladder to a gas generator.

18. The safety belt of claim 15, wherein the inner bladder is a seamed bladder.

19. The safety belt of claim 18, wherein the inner bladder is uniformly bonded to the inner surface of the inflatable braided tube.

20. The safety belt of claim 15, wherein the ends of the inner bladder are brought together and flattened, and wherein the flattened ends of the inner bladder are bound by stitching.

21. The safety belt of claim 11, wherein the con¬ tinuous fibers are selected from aramid, nylon and dacron fibers.

22. The safety belt of claim 21, wherein the braided tube is impregnated with an elastomeric material.

23. The safety belt of claim 22, wherein the elastomeric material is silicone rubber.

24. A method for protecting the occupants of a vehicle comprising:

(a) a safety belt comprised of:

(i) a lap belt comprising an inflatable braided tube having a door end and an inner end, and a first short strap attached to the door end of the inflatable braided tube, said first short strap being anchored to the vehicle or seat,

(ii) a shoulder belt looped through a first part of a buckle assembly, and attached to the inner end of the inflatable inner tube,

(iii) a second part of a buckle assembly, said second part of the buckle assembly being releasably connectable to the first part of the buckle assembly, and

(iv) a second short strap attached to the second part of the buckle assembly said second short strap being anchored to the vehicle or seat, wherein the inflatable braided tube comprises continuous fibers forming spirals which cross each other at fiber crossing points, and which form acute longitudinal angles at the fiber crossing points;

(b) a mechanism for detecting an impact;

(c) a mechanism for igniting a gas generator fluidly connected to the inflatable braided tube, producing a gas which inflates the braided tube, such that the longitudinal angles increase to at least 50°, and the length of the inflatable braided tube decreases by at least 10%, reducing the length of the safety belt pretensioning the safety belt.

25. The method of claim 24, wherein the inflatable braided tube comprises an inner bladder.

26. The method of claim 24, wherein the inner bladder is attached to the inner surface of the inflatable braided tube by an adhesive.

27. The method of claim 24, wherein the inner bladder is a seamed bladder.

28. The method of claim 27, wherein the inner bladder is uniformly bonded to the inner surface of the inflatable braided tube.

29. The method of claim 24, wherein prior to inflation the longitudinal angles range from 30° to 70°, and after inflation the longitudinal angles range from 50° to 110°.

30. The method of claim 29, wherein after inflation the longitudinal angles are approximately 100° .

31. A safety belt comprising:

(b) a first part of a buckle assembly attached to the door end of the inflatable braided tube; (c) a second part of a buckle assembly, said second part of the buckle assembly being releasably connectable to the first part of the buckle assembly;

(e) a gas generator fluidly connected to the inflatable braided tube, wherein the inflatable braided tube comprises continuous fibers, the continuous fibers forming spirals and crossing each other at fiber crossing points, such that when the braided tube is in its uninflated state, the continuous fibers form longitudinal angles ranging from 30° to 70° at the fiber crossing points, and as the braided tube is inflated, the longitudinal angles increase to 50° to 110°, causing the length of the inflatable braided tube to decrease by at least 10%.

32. The safety belt of claim 31, wherein, upon inflation, the inflatable braided tube decreases its length by 10% to 50%.

33. The safety belt system of claim 31, wherein the uninflated width of the inflatable braided tube is approximately two inches.

34. The safety belt of claim 31, wherein the inflatable braided tube can be fully inflated by filling the braided tube with gas to a relative internal pressure of approximately 1 to 4 bars.

35. The safety belt of claim 31, wherein the inflatable braided tube comprises an inner bladder.

36. The safety belt of claim 35, wherein the inner bladder is attached to the inner surface of the inflatable braided tube by an adhesive.

37. The safety belt of claim 35, wherein the inner bladder is a seamed bladder.

38. The safety belt of claim 37, wherein the inner bladder is uniformly bonded to the inner surface of the inflatable braided tube.

39. The safety belt of claim 31, wherein the continuous fibers are selected from aramid, nylon and dacron fibers.

40. The safety belt of claim 39, wherein the braided tube is impregnated with an elastomeric material.

41. The safety belt of claim 40, wherein the elastomeric material is silicone rubber.

42. The safety belt of claim 40, wherein the elastomeric material is urethane.