Safety belt arrangement in motor vehicles having a belt tensioner

• US 5,743,480 A
• Filed: 01/31/1996
• Issued: 04/28/1998
• Est. Priority Date: 02/01/1995
• Status: Expired due to Term

• Current Assignee: Takata (Europe) Vehicle Safety Technology GmbH
• Original Assignee: Takata (Europe) Vehicle Safety Technology GmbH
• Inventors: Kempfle, Thomas, Husung, Christian, Diepold, Ulrich, Wittmann, Robert, Wengert, Andreas, Kopetzky, Robert, Bannert, Georg, Wifling, Martin
• Primary Examiner(s): Jillions, John M.
• Application Number:
  US08/594,579
• Time in Patent Office: 818 Days
• Field of Search: 242/374, 280/806, 280/807, 297/478, 297/480
• US Class Current: 242/374
• CPC Class Codes: B60R 2022/468 characterised by clutching means between actuator and belt reel
• CPC Class Codes: B60R 22/4628 characterised by fluid actuators, e.g. pyrotechnic gas generators actuating a cable B60R22/4619

Abstract

The invention relates to a safety belt arrangement in vehicles having a belt tensioner comprising: a holder which is to be secured to the vehicle chassis, with a belt winding reel with a safety belt wound thereon being rotatably mounted on the holder; a belt retraction spring arrangement by means of which the safety belt is continuously lightly pretensioned in the draw-in direction so that it only loosely lies against the vehicle occupant secured by it; and an auxiliary drive which is separated drivewise by a clutch from the belt winding reel but is activated abruptly with an accident-dependent acceleration and is rotationally fixedly coupled to the belt winding reel via the then engaged clutch. The auxiliary drive has two band running chambers separated by sealing walls and two draw bands which are each arranged in one band running chamber, with the draw bands being secured at one end to a housing and at the other end to a drive reel and being acted on by the pressure source in the event of an accident-dependent acceleration of the vehicle in order to drive the drive reel which is fixedly connected to the belt winding reel in the belt draw-in direction. In accordance with the invention, the clutch is accommodated in a hollow coupling cavity provided in the drive reel.

Claims

1. A safety belt arrangement in motor vehicles having a belt tensioner comprising:

a holder to be secured to the vehicle chassis, with a belt winding reel with a safety belt wound thereon being rotatably mounted on the holder;

a belt retraction spring arrangement by means of which the safety belt is continuously lightly pretensioned in the drawing direction so that it only loosely lies against the vehicle occupant secured by it;

a fixing arrangement, in particular between the belt winding reel and the holder on the vehicle chassis, which, on suddenly pulling on the belt and/or with an accident-dependent acceleration, blocks the safety belt against being pulled out;

an auxiliary drive connected via a clutch to the belt winding reel, the auxiliary drive being normally separated drivewise by the disengaged clutch from the belt winding reel, but being activated abruptly with an accident-dependent acceleration and being rotationally fixedly coupled to the belt winding reel via the then engaged clutch in order to reel up the safety belt by a length such that the safety belt lies tightly against the vehicle occupant before the vehicle occupant secured by it falls into the safety belt;

with the auxiliary drive having;

a pressure source, in particular a pyrotechnical pressure source, which can be triggered or ignited with an accident-dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure space;

a torque generating device acted on by the pressure in the pressure space; and

a drive shaft or a drive reel connected to the torque generating device which is rotationally fixed connected to the belt winding reel via the clutch,

wherein the torque generating device has at least one flexible draw band, in particular consisting of spring steel, which is secured at the one end, at a first mounting point, to the circumference of the drive shaft, or to a drive reel concentrically mounted thereon, and is partially wound onto the drive shaft or onto the drive reel, and is secured at the other end, at a second mounting point, to the peripheral wall of a band running chamber disposed within a housing and arranged around the drive shaft or the drive reel with the housing including an end wall portion adjacent the belt reel,

wherein the band running chamber has a width corresponding to the width of the draw band, in such a way that the draw band, which divides the band running chamber into two partial spaces sealed off from one another, extends through the band running chamber,

wherein the partial space, which brings about an unwinding of the draw band from the rotating shaft or drive reel when subjected to pressure, is connected to the pressure space and the other partial space is vented, and

wherein, for the decoupling of the partial spaces pressure-wise, at least one sealing wall is provided between the housing and the periphery of the drive shaft or of the drive reel concentrically mounted thereon, or the flexible draw band wound thereon,

the drive shaft, or the drive reel, containing a hollow coupling space, the peripheral wall of which is formed as a rotary engagement surface and in which a rotary clutch member rotationally fixedly connected to the belt winding reel is concentrically arranged, with its peripheral wall being formed as a clutch engagement surface; and

an intermediate space between the rotary engagement surface and the clutch engagement surface in which coupling elements which are normally out of engagement with the clutch engagement surface are arranged which produce a rotationally fixed coupling engagement between the rotary engagement surface and the clutch engagement surface when the drive shaft or the drive reel starts a rotary process in the event of triggering of the pressure source,

wherein the coupling elements are coupling pins which are radially movably held, which extend axially into the intermediate space and which stand at least approximately in contact with the rotary engagement surface and also move radially inwardly against the clutch engagement surface on the start of their rotation in the case of a triggering of the pressure source and are clamped or latched between the rotary engagement surface and the clutch engagement surface in such a way that a rotationally fixed coupling engagement is present between the rotary engagement surface and the clutch engagement surface, and

the coupling pins are releasable relative to their holder with a predetermined loading during a triggering, and in particular are designed to be sheared off, and the coupling pins are initially releasably mounted in the end region axially remote from the housing end wall portion in mounting recesses of a centering ring which is rotationally fixedly connected to the drive shaft, or to the drive reel, and are axially subsequently in peripheral engagement with fixed abutment surfaces of the housing in such a way that, on the start of rotation of the drive shaft, or of the drive reel, and on co-movement of the coupling pins caused thereby, the mounting of the coupling pins at the centering ring is released and the coupling pins come into an angular position relative to the centering ring where they are displaced radially inwardly towards the clutch engagement surface.

2. Safety belt arrangement in accordance with claim 1, wherein the mounting recess is at least partially closed at the side opposite to the direction of rotation of the centering ring by a holding/deviating nose which, at the start of rotation of the centering ring resiliently deflects or is sheared off and thus releases the coupling pins.

3. Safety belt arrangement in accordance with claim 1, wherein abutment surfaces project axially from a cover and a receiving space for the ends of the coupling pins is provided between abutment surfaces which follow one another in the peripheral direction.

4. Safety belt arrangement in accordance with claim 1, wherein approximately four to sixteen coupling pins are provided which are substantially uniformly distributed around the periphery.

5. Safety belt arrangement in accordance with claim 1, the clutch engagement surface is provided with axially extending teeth, and in that the coupling pins fit in form-locked manner into the tooth recesses.

6. A safety belt arrangement in motor vehicles having a belt tensioner comprising:

a holder to be secured to the vehicle chassis, with a belt winding reel with a safety belt wound thereon being rotatably mounted on the holder;

a belt retraction spring arrangement by means of which the safety belt is continuously lightly pretensioned in the draw-in direction so that it only loosely lies against the vehicle occupant secured by it;

a fixing arrangement, in particular between the belt winding reel and the holder on the vehicle chassis, which, on suddenly pulling on the belt and/or with an accident-dependent acceleration, blocks the safety belt against being pulled out;

an auxiliary drive connected via a clutch to the belt winding reel, the auxiliary drive being normally separated drivewise by the disengaged clutch from the belt winding reel, but being activated abruptly with an accident-dependent acceleration and being rotationally fixedly coupled to the belt winding reel via the then engaged clutch in order to reel up the safety belt by a length such that the safety belt lies tightly against the vehicle occupant before the vehicle occupant secured by it falls into the safety belt;

with the auxiliary drive having;

a pressure source, in particular a pyrotechnical pressure source, which can be triggered or ignited with an accident-dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure space;

a torque generating device acted on by the pressure in the pressure space; and

a drive shaft or a drive reel connected to the torque generating device which is rotationally fixedly connected to the belt winding reel via the clutch,

wherein the torque generating device has at least one flexible draw band, in particular consisting of spring steel, which is secured at the one end, at a first mounting point, to the circumference of the drive shaft, or to a drive reel concentrically mounted thereon and is partially wound onto the drive shaft or onto the drive reel, and is secured at the other end, at a second mounting point, to the peripheral wall of a band running chamber disposed within a housing and arranged around the drive shaft or the drive reel,

wherein the band running chamber has a width corresponding to the width of the draw band, in such a way that the draw band, which divides the band running chamber into two partial spaces sealed off from one another, extends through the band running chamber,

wherein the partial space, which brings about an unwinding of the draw band from the rotating drive shaft or drive reel when subjected to pressure, is connected to the pressure space and the other partial space is vented,

and wherein, for the decoupling of the partial spaces pressure-wise, at least one sealing wall is provided between the housing and the periphery of the drive shaft or of the drive reel concentrically mounted thereon or the flexible draw band wound thereon,

the drive shaft or the drive reel containing a hollow coupling cavity, the peripheral wall of which is formed as a rotary engagement surface and in which a rotatable clutch member rotatably fixedly connected to the belt winding reel is concentrically arranged, with the peripheral wall of the rotary clutch member being formed as a clutch engagement surface; and

the drive shaft or the drive reel consists of a plurality of hollow sectors, two hollow sectors, which are normally diametrically spaced apart, but which, at the start of a rotation of the drive shaft or of the drive reel, move towards one another in the event of a triggering of the pressure source, with the rotary engagement surface and the clutch engagement surface coming into rotationally fixed coupling engagement.

7. Safety belt arrangement in accordance with claim 6, wherein the hollow sectors in particular are normally kept spaced apart by at least one spring which, however, at the start of a rotation of the drive shaft or the drive reel in the event of triggering of the pressure source, permits the approach of the hollow sectors which is necessary for the coupling engagement.

8. Safety belt arrangement in accordance with claim 7, wherein the spring is an open spring ring which acts from the radially inner side on the hollow sectors and is arranged in a peripheral groove in the inner wall of the hollow sectors in such a way that the spring ring does not prevent the entry into engagement of the rotary engagement surface with the clutch engagement surface.

9. Safety belt arrangement in accordance with claim 6, wherein the hollow sectors are normally pressed radially outwardly against a radial abutment surface fixed to the housing, by a spring, and are in this way held spaced apart;

and cam surface pairs are provided between the hollow sectors and the housing which, in the rest position of the torque generating device, determine the position of the hollow sectors where they are out of the coupling engagement with a coupling member, but which, on relative rotation through a small angle, pushes the hollow sectors radially inwardly into coupling engagement with the rotary clutch member.

10. Safety belt arrangement in accordance with claim 9, wherein the cam surface pairs are formed by the flanks of teeth and recesses cooperating therewith which are provided around a recess provided at the housing and around an abutment ring arranged at the hollow sectors.

11. Safety belt arrangement in accordance with claim 9, wherein the cam surface pairs are provided at both end faces of the hollow sectors.

12. Safety belt arrangement in accordance with claim 11, wherein the springs are formed by elastic members arranged between the hollow sectors.

13. Safety belt arrangement in accordance with claim 6, wherein the angle through which the rotary clutch member must be turned until the coupling engagement between the drive shaft or the drive reel and the rotary clutch member is completed amounts to 5°

to 20°

, preferably 5°

to 15°

, and in particular to about 10°

.

14. Clutch for a safety belt arrangement in motor vehicles for providing a rotationally fixed coupling between a drive shaft, or a drive reel, and a belt winding reel,

wherein the drive shaft, or the drive reel, contains a hollow coupling space, the peripheral wall of which is formed as a rotary engagement surface and in which a rotary clutch member rotationally fixedly connected to the belt winding reel is concentrically arranged, with its peripheral wall being formed as a toothed clutch engagement surface,

wherein an intermediate space is left between the rotary engagement surface and the clutch engagement surface in which coupling elements which are normally out of engagement with the clutch engagement surface are arranged,

wherein the coupling elements are clutch pins having opposite ends and which are radially movably held, which extend axially into the intermediate space and which stand during coupling in contact with the rotary engagement surface and the clutch engagement surface,

wherein the rotary engagement surface includes a cam surface and the clutch pins are radially inwardly movable against the clutch engagement surface due to the cam surface such that the clutch pins are first urged radially inwardly at one of their ends and then also on their other ends.

15. Clutch for a safety belt arrangement in motor vehicles for providing a rotationally fixed coupling between a drive shaft, or a drive reel, and a belt winding reel,

wherein a clutch disc is rotationally fixedly connected to the drive shaft, or to the drive reel, said clutch disc being surrounded by a clutch wall which is rotationally fixedly connected to the belt winding reel, the clutch wall having a smooth interior surface facing the clutch disc and which is free of projections or teeth,

wherein a plurality of toothed clutch segments are provided which are pivotable into coupling engagement with the smooth surface of the clutch wall for providing a compressive coupling engagement between the toothing of the clutch segments and the smooth surface of the coupling wall.

16. Clutch for a safety belt arrangement in motor vehicles for providing a rotationally fixed coupling between a drive shaft, or a drive reel, and a belt winding reel,

wherein the drive shaft, or the drive reel, contains a hollow coupling space, the peripheral wall of which is formed as a rotary engagement surface and in which a rotary clutch member rotationally fixedly connected to the belt winding reel is concentrically arranged, with its peripheral wall being formed as a clutch engagement surface,

wherein an intermediate space is left between the rotary engagement surface and the clutch engagement surface in which coupling elements which are normally out of engagement with the clutch engagement surface are arranged,

wherein the coupling elements are clutch pins which are radially movably held, which extend axially into the intermediate space and which stand during coupling in contact with the rotary engagement surface and the clutch engagement surface,

wherein a centering ring is provided which is rotationally fixedly connected to the drive shaft, or to the drive reel, said centering ring releasable mounting said clutch pins, and

wherein said clutch pins are in engagement with fixed abutment surfaces after release in such a way that, on the start of rotation of the drive shaft, or of the drive reel, and on co-movement of the clutch pins caused thereby, the mounting of the clutch pins at the centering ring is released and the clutch pins come into an angular position relative to the centering ring for being displaced radially inwardly towards the clutch engagement surface.

17. Clutch for a safety belt arrangement in motor vehicles for providing a rotationally fixed coupling between a drive shaft, or a drive reel, and a belt winding reel,

wherein the drive shaft, or the drive reel, contains a hollow coupling space, the peripheral wall of which is formed as a rotary engagement surface and in which a rotary clutch member rotationally fixedly connected to the belt winding reel is concentrically arranged, with its peripheral wall being formed as a clutch engagement surface,

wherein an intermediate space is left between the rotary engagement surface and the clutch engagement surface in which coupling elements which are normally out of engagement with the clutch engagement surface are arranged,

wherein the coupling elements are clutch pins which are radially movably held, which extend axially into the intermediate space and which stand during coupling in direct contact with the rotary engagement surface and the clutch engagement surface, and

wherein holding means are provided for releasably securing an end of the clutch pins and adapted to shear the pins upon a rotational movement with the pins no longer being secured by the holding means and being clamped between the rotary and clutch engagement surfaces so that only single clutch pins are present at distinct locations between the engagement surfaces for providing a particularly defined control of the clutch pins.