Passive Seat Belt System

1. Field of the Invention

This invention relates to a passive seat belt system.

2. Description of the Prior Art

Various passive seat belt systems have heretofore been suggested. One type of passive seat belt system is a so-called three point system which includes a fixed length of webbing attached to upper and lower portions of the vehicle door and a junction ring slidably mounted on the webbing and attached to a length of webbing which is stowed on a seat belt retractor mounted inboard of the seat, such as under a center arm rest. A disadvantage of such system is that ingress by the occupant is inconvenient because the webbing lies close to the seat cushion and the occupant must lift the webbing and slide under the webbing to insure that the webbing is automatically placed in its proper position upon actuation of a predetermined event, such as closing of the vehicle door.

Various devices have been proposed to move the inboard belt position upwards and forwards, commensurate with door opening, to alleviate the above problems. An example of one such system is that disclosed in my U.S. Application Ser. No. 62,277 filed July 30, 1979, in which an auxiliary power device is utilized to move the webbing forwards. However, such devices tend to be expensive and complicated as they require an auxiliary power device to operate the articulation device. Other proposed devices require an intentional act by the occupant to move the belt to a noninterferring position. It would be desirable if a passive seat belt system were provided that alleviated the above problems.

In accordance with this invention, there is provided a vehicle passive seat belt system comprising a seat belt adapted to be automatically placed in a restraining position about an occupant seated in a seat in the vehicle adjacent to a vehicle door, the seat belt extending at least across the upper torso of the occupant; the seat belt being anchored to the vehicle at a first mounting point located at a position adjacent the seat inboard of the door and at a second mounting point located adjacent the outboard side of the seat; and means to automatically move one of the first and second mounting points from a first position at which the belt is in a restraining position about the occupant when seated in the seat to a second position at which the belt is in a non-restraining position about the occupant when seated in the seat, the means being non-motorized and being actuated in response to a force applied to the belt.

In addition, this invention provides a vehicle passive seat belt system comprising a seat belt adapted to be automatically placed in a restraining position about the occupant seated in a seat in the vehicle, the seat being adjacent to a door in the vehicle, the seat belt extending across at least the upper torso of the occupant; the seat belt being anchored to the vehicle at a first mounting point located at a position adjacent the seat inboard of the door; and means to automatically move the first mounting from a first restraining position to a second non-restraining position. In further accordance with this invention, there is provided a seat belt system in which a seat belt retractor is normally in a non-load transfer position and is placed into a load-transfer position upon an emergency condition in the vehicle.

FIG. 1 is a perspective view of one embodiment of the passive seat belt system of this invention.

FIG. 2 is a side view of the seat belt retractor mechanism of the system of FIG. 1 as shown in its restraining and non-restraining positions.

FIG. 3 is a top view of the retractor mechanism of FIG. 2.

FIG. 4 is a cross-sectional view of the retractor mechanism of FIG. 2.

With reference to FIG. 1, there is shown an embodiment of the passive seat belt system of this invention, generally indicated at 10, in a vehicle having a door 12 and a seat 14 adjacent thereto. Although seat 14 as shown is a bench seat, it is to be understood that the invention is applicable to a bucket-type seat as well. Inboard of door 12 on seat 14 is an arm rest or console 16. A three-point seat belt is provided for seat 14. This includes a fixed length of webbing which is attached to door 12 at an upper position via an anchor plate 18 on the frame of door 12 adjacent window 20 and at a lower position via anchor plate 22 affixed on the lower portion of door 12. Such webbing extends intermediate anchor plates 18 and 22 through a junction ring 24. As can be seen, the webbing is in the form of a shoulder belt 26 which is adapted to extend across the upper torso of the occupant from anchor plate 18 to junction ring 24 and a lap belt portion which is adapted to extend across the pelvic region of the occupant from junction ring 24 to anchor plate 22. Lap and shoulder belt portions 26 and 28 are adapted to freely slide through junction ring 24. Fixedly attached to junction ring 24 is one end of a connecting belt 30, the other end of which is mounted upon a seat belt retractor 32 mounted to the vehicle beneath arm rest 16. The system as described above is similar to that disclosed in U.S. Patent Application Ser. No. 57,605 filed July 16, 1979, and junction ring 24 may be provided with a lock feature as disclosed in said application. In addition, if desired either anchor plate 18 or 22 may be provided with a releasable interconnection in the form of a buckle and tongue assembly or the like, or an emergency release mechanism may be provided in retractor 32 to provide a means for disconnecting the passive seat belt system in the event of an emergency.

In accordance with this invention, the spool assembly of retractor 32 is mounted for forwards and upwards displacement within arm rest 16 as viewed in FIG. 1. Slots 34 are provided on both sides of arm rest 16 to accommodate movement of the connecting belt 30 for each seating position as the respective spool assembly associated with the respective retractor is moved.

A spirally grooved shaft 36 is non-rotatably anchored interiorly of arm rest 16. One end of shaft 36 is fixed in plate 40 located at the forward end 38 of arm rest 16 and the other end of shaft 36 is fixedly mounted to a lower frame 42 of retractor 32 located at the rearward end 44 of arm rest 16. The pitch of spiral groove 46 of shaft 36 is chosen so as to be smaller at both ends than in the center section 48. Over the rearward end of shaft 36 is a slip fitting bushing 50 which is keyed at 52 to the rotation of spool assembly 54 of retractor 32 upon which webbing 30 is wound. The inner end of a conventional rewind spring 56 is attached to bushing 50 and the outer end of spring 56 is fixed to cover 58 which contains spring 56 and which is mounted to upper frame 60 of retractor 32. A spiral groove follower 62, in the form of a ball 64 and plug 66, is contained in bushing 50 so that rotation of bushing 50 causes the spool assembly 54 and upper frame 60 to linearly traverse shaft 36 in accordance with the pitch of spiral groove 46.

Spool assembly 54 includes a central tube or spool 68 and end gears 70. One end of webbing 30 is attached to spool 68. Gears 70 are in the form of ratchet wheels which have ratchet teeth along their periphery, as is conventional. Spool assembly 54 is fixed for rotation with bushing 50 through which shaft 36 extends. Upper housing 60 is in the form of a U-shaped frame including side flanges 72 through which both bushing 50 and shaft 36 extend. Bushing 50 is rotatably mounted within flanges 72. Extending across side flanges 72 are two spring members 74 upon which are rotatably mounted upper and lower rollers 76. Rollers 76 are adapted to contact the interior side surface 78 of arm rest 16 in order to prevent upper frame from rotating as the frame traverses groove 46 due to the torque transmitted from rotation of spool assembly 54.

Lower frame 42 of retractor 32 includes side flanges 80 and a base portion 82. Mounted within side flanges 80 is a plastic saddle 84 from which a weighted pendulum 86 is suspended. Pendulum 86 includes a cap 88 which is in contact with a portion 90 of locking dog (pawl) 92 which is also supported in saddle 84. A deceleration force acting on the vehicle causes pendulum 86 to pivot and lift up pawl 92 which engages with the ratchet teeth on gears 70 to lock the retractor against rotation in the extraction direction and thus prevent additional extraction of webbing from spool 68. Lower frame 42 is mounted via bolt 94 to a mounting surface in the vehicle, such as the seat or the floor. Back surface 73 of upper frame 60 is provided with a U-shaped tang 96 which is adapted to engage lower frame 42 through an opening 98 in lower frame 42 to provide load transfer contact between the upper and lower frames, as described below.

In operation of the above-described embodiment, when door 12 is in a closed position with shoulder belt 26 and lap belt 28 in their restraining positions, upper frame 60 of retractor 32 is located at its most rearward position so that tang 96 is adjacent to opening 98 and the upper and lower frames of retractor 32 are positioned for load transfer engagement in the event of a deceleration of the vehicle above a predetermined level. When door 12 is opened, webbing 30 is extracted from the rewind mechanism off of spool 68. Rotation of spool 68 and gears 70 fixed thereto causes rotation of bushing 50 together with upper frame 60 on spiral groove 46 of shaft 36. Since the pitch of groove 46 is relatively small at the rearward end of shaft 36, initial extraction of webbing 30 results only in a slight linear motion of bushing 50 and upper frame 60 on shaft 36, so that tang 96 still remains close to and engageable with opening 98. The amount of webbing which may be extracted without significant linear motion of the rewind mechanism on shaft 36 is selected so as to insure that there remains a load transfer positioning of the upper and lower frames regardless of the size the occupant or the position of seat 14. For example, the pitch of groove 46 may be selected so that about 25 cm of webbing may be extracted from spool 68 without separation of the upper and lower retractor frames from their load transfer positions.

As further webbing is extracted from spool 68 due to further opening of door 12, bushing 50 and upper frame 60 linearly traverse shaft 36 to the left in FIG. 2 (in a diagonally upwards direction in FIG. 1) to their forwardmost position 100 adjacent to plate 40. The pitch of groove 46 is selected such that some excess webbing may be extracted from spool 68 without bottoming the assembly in that position. Contact of rollers 76 against inner surface 78 of arm rest 16 prevents the torque resulting from rotation of spool 68 from rotating upper frame 60.

When the inboard anchoring point for the belt has moved forwards and upwards, additional room is provided for occupant ingress, without having to lift the belts off of the seat. When door 12 is closed, excess webbing is taken up by spool 68 rotating in the opposite direction due to the bias of its rewind spring 56. Rotation of spool 68 in the rewind direction causes rotation of bushing 50 along shaft 36 linearly to the right in FIG. 2 (in a diagonally rearward and downward direction in FIG. 1) to its original position. As indicated above, when a predetermined amount of webbing remains to be rewound onto retractor 32, upper frame 60 has returned to its position in which it is positioned for engagement with lower frame 42.

In the event that a deceleration of the vehicle is above the predetermined level and thus causes lock up of the pawl and ratchet teeth, forces tending to rotate spool 68 in the extraction direction (clockwise in FIG. 4) transfer such rotary force to upper frame 60 through pawl 92. This results in a slight rotary motion of upper frame 60 in the direction of arrow A (clockwise) against the bias of springs 74 so that tang 96 extends through opening 98 in lower frame 42. In this manner, the load is transferred to the lower frame of the retractor and thence to the vehicle structure. Rotation of upper frame 60 causes compression of upper spring 74 due to contact of its associated roller 76 with interior side 78 of arm rest 18. Should the collision forces be mild, spring 74 will return upper frame 60 to its original position.

Although in the above embodiment the automatically movable anchor point has been described as being the inboard anchor point, this invention also contemplates movement of the outboard anchor point should the retractor be mounted on the outboard side of seat 14, such as on door 12 or on the roof or floor of the vehicle. Furthermore, this invention is also applicable to a two-point belt system in which a single diagonal belt is adapted to extend across the upper torso of the occupant and a knee bolster is mounted on the dashboard to provide lower body restraint.

It is also to be noted that upper frame 60 and belts 26 and 28 may be moved forwardly of their restraint positions by the occupant manually extending belt 30 in a forwards direction to extract additional webbing from retractor 32.

The present invention provides a relatively inexpensive and uncomplicated passive seat belt system with improved ingress capability which does not require an intentional act by the occupant or the use of motorized devices.

It is to be understood that variations and modifications of the present invention may be made without departing from the scope thereof. It is also to be understood that the present invention is not to be limited by the specific embodiments disclosed herein but only in accordance with the appended claims when read in light of the foregoing specification.