Belt tensioner for safety belts for motor vehicles
First Claim
1. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the flexible draw band (21) extends through the band running chamber (23) up to its peripheral wall (30) with the same direction of curvature which it has as a result of being wound onto the drive shaft (19) or onto the drive reel (22).
1 Assignment
0 Petitions
Accused Products
Abstract
A belt tensioner for safety belt arrangements in motor vehicles has a holder (11) on which are provided a belt winding reel (12) with a safety belt (13) coiled thereon, a blocking arrangement and an additional drive (15) connected via clutch (20) to the belt winding reel (12). The additional drive (15) contains a pressure source (16) which abruptly builds up a high pressure in a pressure chamber on being triggered and also contains a torque generating device (18) acted on by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the latter. The drive shaft (19) is rotationally fixedly connectable to the belt winding reel (12) via the clutch (20). The torque generating device (18) includes a flexible draw band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19) or to the drive reel (22) concentrically mounted thereon and is partially wound onto the drive shaft (19), or onto the drive reel (22) and is secured at the other end, at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) within a housing (24). Pressure applied to the draw band causes belt tensioning movement of the drive shaft (19) or drive reel (22).
42 Citations
34 Claims
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1. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the flexible draw band (21) extends through the band running chamber (23) up to its peripheral wall (30) with the same direction of curvature which it has as a result of being wound onto the drive shaft (19) or onto the drive reel (22).
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
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2. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the Other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the sealing wall or walls (29) has or have a sealing lip (29'"'"') facing the outer surface of the coiled up draw band (21) and so extends or extend relative to the housing, and is or are so flexibly or hingedly designed or arranged, that the pressure in the associated pressure chamber (23'"'"') sealingly presses the sealing lip (29'"'"') against the outer surface of the coiled up draw band (21).
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the Other partial space (23") is vented; and
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3. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the radial extent of the band running chamber varies in dependence on the angle of rotation relative to the axis of rotation of the drive shaft (19) or of the drive reel (20). - View Dependent Claims (4, 5)
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
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6. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by meads of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein a plurality of draw bands (21) and associated band running chambers (23) are provided distributed over the periphery of the drive shaft (19), or of the drive reel (22), and are separated from one another in pressure-tight manner by sealing walls (29). - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
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15. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the end of the draw band or draw bands (21) located at the drive shaft (19) or drive reel (22) is normally kept engaged in the drive shaft (19), or in the drive reel (22) by the layers of the draw bands (21) which stand under tension on the drive shaft (19) or drive reel (22) and can be automatically disengaged in the radial direction on a drop in pressure following triggering, with the tension prior to triggering in the normal state being ensured by a retaining means which holds the drive shaft (19) or the drive reel (22) in the tensioned state until triggered and is made inactive by the pressure generated in the pressure chamber (17) on triggering of the pressure source. - View Dependent Claims (16)
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
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17. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein a region of the or each sealing wall (19) facing the drive shaft (19), or drive reel (22), is formed so that it can pivot away in the direction of the pressure loaded partial chamber (23) through the spring tension of the coiled up draw band regions and/or through an additional spring.
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
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18. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13) to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pyrotechnical pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20) characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23'"'"') is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the retraction spring arrangement (14'"'"') is arranged at the same end face of the belt winding reel (12) as the additional drive
115) and the clutch (20), with the additional drive (15) and the clutch (20) lying between the retraction spring arrangement (14'"'"') and the belt winding reel (12), and the parts of the additional drive (15) lying on the axis of rotation (38) and the clutch (20) have axial cavities in the region of the rotational axis for the passage of an inner shaft (41) which rotationally fixedly connects the retraction spring arrangement (14'"'"') with the belt winding reel (12).
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23'"'"') is vented; and
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19. Belt tensioner for safety belt arrangements in motor vehicles having a holder (11) secured to the vehicle chassis and on the holder a belt winding reel (12) with a safety belt (13) wound thereon, a retraction spring arrangement (14, 14'"'"') by means of with the safety belt (13) is continuously and lightly so pretensioned in the retraction direction that it only lies loosely on the vehicle occupant secured by it, a blocking arrangement between the belt winding reel (12) and the holder (11) of the vehicle chassis which blocks the safety belt (13) against being pulled out if suddenly pulled, and/or in the event of an acceleration resulting from an accident, and an additional drive (15) connected to the belt winding reel (12) via a clutch (20), wherein the additional drive (15) is normally separated drivewise from the belt winding reel (12) by the disengaged clutch (20), but is abruptly activated in the event of a acceleration resulting from an accident and is rotationally fixedly coupled with the belt winding reel (12) via the then engaged clutch (20) in order, before the vehicle occupant accelerates against the safety belt (13), to wind up such a length of the safety belt that the safety belt lies tightly on the vehicle occupant, with the additional drive (15) having a pyrotechnical pressure source which is triggered or ignited by the accident dependent response of an acceleration sensor and which, on being triggered, abruptly builds up a high pressure in a pressure chamber (17), a torque generating device (18) which is energised by the pressure in the pressure chamber (17) and a drive shaft (19) connected to the torque generating device (18) which is rotationally fixedly connected with the belt winding reel (12) via the clutch (20), characterised in that the torque generating device (18) has at least one flexible tension band (21) which is secured at one end at a first mounting point (25) to the periphery of the drive shaft (19), or to the drive reel (22) which is concentrically mounted thereon, and is partially wound onto the drive shaft (19), or onto the drive reel (22), and is secured at the other end at a second mounting point (26) to the peripheral wall (30) of a band running chamber (23) which is arranged within a housing (24) around the drive shaft (19), or around the drive reel (22) and has a width corresponding to the width of the draw band (21) in such a way that the draw band (21) extends through the band running chamber (23) while subdividing the band running chamber (23) into two partial chambers (23'"'"', 23") sealed off relative to one another;
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
in that for the pressure-wise decoupling of the partial chambers (23'"'"', 23"), at least one sealing wall (29) is provided which extends between the housing (24) and the periphery of the flexible draw band (21) which is wound onto the drive shaft (19), or onto the drive reel (22) concentrically mounted thereon wherein the clutch (20) can be engaged by the pressure generated by the triggering of the pressure source (16), and in that the additional drive (15) is separated from the pressure source by a valve arrangement (59, 64,
65) until the clutch (20) has engaged. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
- and in that the partial chamber (23'"'"') which on being subjected to pressure brings about an unwinding of the tension band (21) from the rotating drive shaft (19) or drive reel (22) is connected to the pressure space (17) and with the other partial space (23") is vented; and
Specification