GB1583443A

GB1583443A - Vehicle with a seat belt system

Info

Publication number: GB1583443A
Application number: GB2006776A
Authority: GB
Original assignee: Kangol Magnet Ltd
Current assignee: Kangol Magnet Ltd
Priority date: 1977-08-10
Filing date: 1977-08-10
Publication date: 1981-01-28

Description

(54) IMPROVEMENTS IN OR RELATING TO A VEHICLE WITH A SEAT BELT SYSTEM (71) We, KANGOL MAGNET LIMITED, of Norfolk Street, Carlisle, Cumbria, CA2 5HX, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a vehicle provided with a seat belt system.

Vehicle seat belt systems of the "passive" type, that is, of the type which come into use without any specific action being required of the user, can include a belt associated with a vehicle door so as to be withdrawn from a retractor against the pull of a retractor spring when the door is opened.

Retractors are required to lock against belt withdrawal in hazardous conditions and where electrically operated they should be 'fail safe' so that they lock in the event of an electrical supply failure. Current must therefore be supplied as long as the retractor is to be unlocked. To avoid an undue load on the vehicle battery, the current must be interrupted when the vehicle is not in use, so the retractor is then locked. There is consequently a difficulty in using this type of retractor where door opening movement requires belt withdrawal and, consequently, an unlocked retractor.

The invention accordingly provides a vehicle comprising a seat belt associated with a vehicle seat, a door adjacent the seat, the belt being associated with the door so as to be withdrawn from a retractor against the pull of a retractor spring when the door is opened, a locking mechanism in the retractor biassed to lock the retractor against belt withdrawal, and electrical control apparatus arranged to be energised to oppose the bias to free the retractor for belt withdrawal in response to a condition corresponding to normal use of the vehicle, and in response to operation of the door, the apparatus being arranged to be de-energized in response to the sensing of a predetermined hazard condition.

The normal use condition of the vehicle can comprise for example occupation of the driver's seat, or operation of the vehicle ignition system. The hazard condition can comprise the sensing of a predetermined acceleration (which term is used herein to include deceleration) and/or the operation of the vehicle brake pedal.

The invention is further explained in the following illustrative description and accompanying drawing, in which: Figures 1 and 2 are scheamtic views of front seats in a vehicle embodying the invention, taken from the front and from above respectively, showing safety belt systems associated with the seats; Figure 3 is a sectional side view on a larger scale of a retractor included in the seat belt systems of figures 1 and 2; and Figure 4 is a circuit diagram including the coil of a solenoid incorporated in the retractor of figure 3.

Figures 1 and 2 show two seats, 1, 11 arranged side by side in a motor vehicle, the seats being for example those of the driver and a passenger in a private car.

Access to each seat is gained by an adjacent front-hinged door 2, 12. At the base of the upright free edge at the rear of each door there is mounted a seat belt retractor 4, 14.

The retractors 4, 14 may be external of the door structure or contained substantially within it as shown. At the tops of the free edges of the door are mounted running loops 5, 15. Belts 6, 16 extend from the retractors 4, 14 respectively upwardly to the associated running loops 5, 15 and thence to a common anchorage position 8, or to separate anchorages, between the seats 1, 11 conveniently on a transmission tunnel 9 as shown.

As may be seen by reference to the left hand side of figure 2, in which the door 2 is shown in the open position, a person entering the vehicle to occupy the seat 1 will place himself between the seat back and the portion of the belt 6 which extends between the loop 5 and the anchorage 8.

On closure of the door behind him, the loop 5 is carried rearwardly so as to extend around the passenger in the manner shown in the right hand side of figure 2. The re tractors 4, 14 are arranged to be locked against belt withdrawal in the event of undue acceleration of the vehicle and the driver and passenger are consequently held in their seats against damaging impact with the vehicle interior.

The retractors 4, 14 are essentially similar and only the retractor 4 will be described in any details with reference to figure 3.

The retractor 4 has a spindle 25 urged by a spring (not shown) to rotate in a direction such as to wind the belt 6 onto the spindle. The belt 6 can be withdrawn against the force of this rewind spring in use by the opening of the door 2. The spindle 25 carries a ratchet wheel 40 with teeth 45 which can be engaged by a tooth portion 44 of a pawl 41 pivotably mounted on a pin 42 projecting from a wall 48 of the retractor housing. A tension spring 46 extending between the pawl 41 and the wall 48 urges the pawl into a locking position in which the tooth portion 44 engages with the teeth 45 to prevent rotation of the spindle 25 in the belt unwinding direction. An electromagnet or solenoid 50 is carried within the retractor housing and when energised holds the pawl 41 against the tension of the spring 46 in the release position shown in which the tooth portion 44 is spaced from the teeth 45 so that the belt 6 can be freely withdrawn. De-energisation of the solenoid 50 thus permits the spring to urge the pawl 41 into the locking position, so locking the retractor against belt withdrawal.

The solenoids 50 of the retractors 4, 14 have respectively coils 51, 52 which are included in the circuit shown schematically in figure 4. Of course if the vehicle has only one of the seat belt systems or more than two, only one solenoid coil, or more than two will be included in the circuit. The coils 51, 52 are connected in parallel with a suitable source of electric current, conveniently the vehicle battery 54 is shown, through a fuse 55 and a group of mechanical switches or other condition responsive devices. As shown, the switches comprise a crash sensor switch 56 and a brake switch 57 which are series connected between the fuse battery 54 and the coils 51, 52, and two further switches, a seat switch 58 and a door switch 59 which are connected in parallel.

The crash sensor controlling the crash sensor switch 56 is responsive to a condition in which it is desired that the retractor 4, 14 lock against belt withdrawal, so that the users are restrained against ejection from their seats. The crash sensor can be an inertial device of any suitable design but is preferably one which is responsive to deceleration in any direction of the vehicle to which it is secured, as opposed to one which is sensitive only to acceleration in the direction of movement of the vehicle. The illustrated safety system is thus effective for example if one side of the vehicle is struck by another. The contacts of the crash sensor switch 56 are normally closed and are arranged to open only when an emergency deceleration is sensed.

The crash sensor may comprise for example a pendulum operated switch, or a ball resting within a circular depression in a support surface. The ball normally occupies the central lowest portion of the depression where its weight is sufficient to depress the actuating element of a microswitch against a spring and thereby hold the micro-switch contacts closed. A sufficient acceleration will cause the ball to roll upwardly within the depression and so free the actuating element for spring urged movement to open the contacts. The depression can be rigid or otherwise shaped so that the contacts are not opened unless the acceleration exceeds a predetermined amount. If a pendulum is employed, it may be arranged to pivot about a position laterally spaced from its centre of gravity, to achieve a similar effect.

The brake switch 57 also has its contacts normally closed and arranged to open only when the vehicle brake pedal is depressed. The brake switch 57 may be operative only when the pedal is fully depressed or is depressed by at least a predetermined amount but no disadvantage is incurred if even a light pressure on the pedal opens the contacts.

The seat switch 58 is incorporated in the structure of the driver's seat. Its contacts are normally open and are arranged to be moved to the closed position when the driver's seat is occupied. The seat switch may if preferred be replaced by a switch arranged to be closed when the ignition key is turned but the retractors will then be locked between closure of the driver's door and his turning of the ignition key. To avoid energisation of the solenoid of passengers seat belt system when the passenger's seat is not in use, a passenger's seat switch 60 can be provided in series with this solenoids coil 51. The switch 60 assumes an open position normally, so that the coil 51 cannot be energised unless the seat is occupied.

The contacts of the door switch 59 are also arranged to be open in normal circumstances, that is when the driver's door is shut, but to close immediately on opening of the door.

Under ordinary driving conditions switches 56, 57 and 58 are closed so that coils 51 and 52 are energised and the belts 6, 16 can be freely withdrawn from the retractors 4, 14. If the crash sensor experiences a sufficient acceleration and/or if the brake pedal is depressed, then at least one of the switches 56 and 57 becomes open so that the retractors become locked against belt withdrawal and the driver and passenger are held in their seats.

The seat and door switches 58 and 59 of course normally come into operation only when the vehicle is stationary and the driver is entering or leaving the vehicle. When the vehicle is unoccupied the coils 51 and 52 are de-energised because, although the crash sensor and brake switches 56 and 57 are closed, both the seat and door switches 58, 59 are open. The retractors 4, 14 are consequently locked against belt withdrawal.

The circuit is completed through the switch 59 as soon as the driver's door is opened, even by a small amount, and however violent the movement, so that the retractors 4, 14 are unlocked and the belts 6, 16 can be withdrawn by further opening of the associated doors and then by the action of the users body as he occupies his seat.

Occupation of the driver's seat closes the switch 58 providing an alternative current path to that through the door switch 59 which is of course interrupted as soon as the driver closes his door. Normal driving conditions are thus reached.

At the end of a normal journey, the driver's door will be opened to close switch 59 so the coils 51, 52 will remain energised even after the driver has left his seat and thereby causes switch 58 to open. When the driver closes his door behind him, door switch 59 also opens and disconnects the coils 51, 52 from the battery 54 so that the retractors 4, 14 are locked until the door is re-opened for reuse of the vehicle.

The system specifically described can be modified within the scope of the invention in a variety of ways. Instead of the diagonal belt system illustrated, a lap and diagonal system can be employed. The retractor also can take a variety of forms. It may be preferred that the retractor be belt sensitive as well as controlled by the crash sensor, that is, it may be arranged also to lock in re sponse to a sharp pull on the belt such as will be experienced when the user is thrown forward in his seat as a result of a sudden deceleration of the vehicle. The sensitivity of the mechanism is then arranged to be such as not to effect locking in response to a violent door opening movement. The strap sensitive locking mechanism described in Specification 1 431 054 could be employed, the device of figures 1 to 3 of that Specification being modified by provision of a spring to urge the lever 28 into the locking position and replacement of the pendulum 24 and pin 25 by a solenoid capable of holding the lever 28 out of the locking position against the pull of the spring.

WHAT WE CLAIM IS: 1. A vehicle comprising a seat belt associated with a vehicle seat, a door adjacent the seat, the belt being associated with the door so as to be withdrawn from a retractor against the pull of a retractor spring when the door is opened, a locking mechanism in the retractor biassed to lock the retractor against belt withdrawal, and electrical control apparatus arranged to be energised to oppose the bias to free the retractor for belt withdrawal in response to a condition corresponding to normal use of the vehicle, and in response to operation of the door, the apparatus being arranged to be de-energized in response to the sensing of a predetermined hazard condition.

2. A vehicle as claimed in claim 1 wherein the normal use condition comprises occupation of the driver's seat.

3. A vehicle as claimed in claim 1 or 2 wherein the normal use condition comprises actuation of the vehicle ignition system.

4. A vehicle as claimed in claim 1, 2 or 3 wherein the hazard condition comprises the sensing of a predetermined vehicle acceleration and/or the operation of the vehicle brake pedal.

5. A vehicle as claimed in claim 1 wherein the apparatus includes an electromagnet arranged, when energized, to act on the locking mechanism to oppose the bias.

6. A vehicle as claimed in claim 5 wherein the control apparatus comprises a circuit including a first normally open switch arranged to close in response to opening of the vehicle door, a second normally open switch arranged to close in response to a driving condition of the vehicle, the first and second switches being parallel connected in the circuit in series with the electromagnet, a current source, and a normally closed switch arranged to open in response to the hazard or potential hazard condition.

7. A vehicle as claimed in claim 6 wherein the driving condition to which the second switch is responsive comprises occupation of the seat or operation of the ignition system of the vehicle.

8. A vehicle as claimed in claim 6 or 7 wherein the normally closed switch means comprises a switch responsive to vehicle acceleration.

9. A vehicle as claimed in claim 8, in which the normally closed switch is responsive to vehicle deceleration only above a predetermined amount.

10. A vehicle as claimed in claim 6, 7, 8 or 9 wherein the normally closed switch means comprises a switch responsive to application of the vehicle brakes.

11. A vehicle as claimed in claim 10 wherein the normally closed switch is responsive to movement of the vehicle brake pedal only beyond a predetermined amount.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. one of the switches 56 and 57 becomes open so that the retractors become locked against belt withdrawal and the driver and passenger are held in their seats. The seat and door switches 58 and 59 of course normally come into operation only when the vehicle is stationary and the driver is entering or leaving the vehicle. When the vehicle is unoccupied the coils 51 and 52 are de-energised because, although the crash sensor and brake switches 56 and 57 are closed, both the seat and door switches 58, 59 are open. The retractors 4, 14 are consequently locked against belt withdrawal. The circuit is completed through the switch 59 as soon as the driver's door is opened, even by a small amount, and however violent the movement, so that the retractors 4, 14 are unlocked and the belts 6, 16 can be withdrawn by further opening of the associated doors and then by the action of the users body as he occupies his seat. Occupation of the driver's seat closes the switch 58 providing an alternative current path to that through the door switch 59 which is of course interrupted as soon as the driver closes his door. Normal driving conditions are thus reached. At the end of a normal journey, the driver's door will be opened to close switch 59 so the coils 51, 52 will remain energised even after the driver has left his seat and thereby causes switch 58 to open. When the driver closes his door behind him, door switch 59 also opens and disconnects the coils 51, 52 from the battery 54 so that the retractors 4, 14 are locked until the door is re-opened for reuse of the vehicle. The system specifically described can be modified within the scope of the invention in a variety of ways. Instead of the diagonal belt system illustrated, a lap and diagonal system can be employed. The retractor also can take a variety of forms. It may be preferred that the retractor be belt sensitive as well as controlled by the crash sensor, that is, it may be arranged also to lock in re sponse to a sharp pull on the belt such as will be experienced when the user is thrown forward in his seat as a result of a sudden deceleration of the vehicle. The sensitivity of the mechanism is then arranged to be such as not to effect locking in response to a violent door opening movement. The strap sensitive locking mechanism described in Specification 1 431 054 could be employed, the device of figures 1 to 3 of that Specification being modified by provision of a spring to urge the lever 28 into the locking position and replacement of the pendulum 24 and pin 25 by a solenoid capable of holding the lever 28 out of the locking position against the pull of the spring. WHAT WE CLAIM IS:

1. A vehicle comprising a seat belt associated with a vehicle seat, a door adjacent the seat, the belt being associated with the door so as to be withdrawn from a retractor against the pull of a retractor spring when the door is opened, a locking mechanism in the retractor biassed to lock the retractor against belt withdrawal, and electrical control apparatus arranged to be energised to oppose the bias to free the retractor for belt withdrawal in response to a condition corresponding to normal use of the vehicle, and in response to operation of the door, the apparatus being arranged to be de-energized in response to the sensing of a predetermined hazard condition.

12. A vehicle as claimed in any one of

claims 2 to 11 having a second, like, seat belt, retractor and electromagnet associated with a second vehicle seat, the second electromagnet being connected in parallel with the first-mentioned electromagnet.

13. A vehicle as claimed in claim 12 wherein the first-mentioned seat is a driver's seat, and the second electromagnet is connected in series with a normally open switch arranged to close in response to occupation of the second vehicle seat.

14. A vehicle as claimed in any preceding claim wherein the or each retractor is carried by the associated door.

15. A vehicle substantially as herein described with reference to the accompanying drawing.