Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R22/00—Safety belts or body harnesses in vehicles
  • B60R22/18—Anchoring devices
  • B60R22/195—Anchoring devices with means to tension the belt in an emergency, e.g. means of the through-anchor or splitted reel type
  • B60R22/1952—Transmission of tensioning power by cable; Return motion locking means therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R22/00—Safety belts or body harnesses in vehicles
  • B60R22/18—Anchoring devices
  • B60R22/195—Anchoring devices with means to tension the belt in an emergency, e.g. means of the through-anchor or splitted reel type
  • B60R22/1954—Anchoring devices with means to tension the belt in an emergency, e.g. means of the through-anchor or splitted reel type characterised by fluid actuators, e.g. pyrotechnic gas generators
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R22/00—Safety belts or body harnesses in vehicles
  • B60R22/34—Belt retractors, e.g. reels
  • B60R22/46—Reels with means to tension the belt in an emergency by forced winding up
  • B60R2022/4685—Reels with means to tension the belt in an emergency by forced winding up with means to adjust or regulate the tensioning force in relation to external parameters

Definitions

• THE PRESENT INVENTION relates to a seat belt pretensioner for a motor vehicle.
• Safety devices of the type described briefly above have been provided so as to be pyrotechnically operable in order to ensure that the safety device is operated in an extremely short period of time so as to be properly deployed in the event of an accident situation such as a crash involving a motor vehicle.
• a drawback of such arrangements is that because such safety devices are pyrotechnically operable, they are one-use items which cannot be re-set after actuation for possible subsequent use.
• a safety device is installed in order to be primed in advance of an accident situation upon receipt of a predictive pre-crash signal, it is clearly advantageous to be able subsequently to re-set the safety device in the event that the accident was avoided or involved only a very low impact.
• Re-settable safety devices of this general type have been proposed previously such as, for example, in US2005/0218632A1 which discloses a motor vehicle provided with a central air supply system in order to operate a number of different pneumatically- operated safety devices such as air-bags and seat-belt pre-tensioners.
• a seat-belt pre-tensioner for a motor vehicle, comprising a piston member displaceable in a chamber under gas pressure applied to said chamber, said piston member being in sealing relationship with the walls of said chamber and said chamber being provided with respective inlets for connection with a source of compressed gas, with a source of gas generated by a pyrotechnic device, and with an outlet for gas, said piston member being coupled to an element outside said chamber which element is coupled in turn with one part of a vehicle safety belt arrangement, whereby displacement of said member in said chamber by gas pressure applied thereto will cause the seat-belt to be pre-tensioned, with the displacement of said piston member, and thus the pre-tensioning, being greater in a case where the pyrotechnic device is fired than when the source of compressed gas alone is connected with said chamber.
• said chamber has a cylindrical wall and opposing end walls and said piston member comprises a vane rotatable about the axis of said cylindrical wall between limiting positions defined by a radially extending blocking member within said chamber whereby the sealing member is rotatable through less than 360° within said chamber, said vane being mounted on a shaft extending axially from said chamber through said end walls and carrying an arm or eccentric carrying a pulley or boss around which is extended a cable, belt or other filament connected with one end of the seat- belt, said blocking member extending sealingly between said cylindrical wall and said shaft and between said end walls, and said vane cooperating sealingly with said cylindrical wall and with said end walls.
• said chamber comprises a cylinder and said piston member is movable axially along said cylinder and has a piston rod connected with a drum around which a cable extends in a loop, one end of the cable being fixed and the other end being connected to said one part of said vehicle safety belt arrangement, said drum being rotatable about an eccentric axis whereby axial movement of the piston and piston rod will turn the drum to extend the loop of said cable around the drum and thereby pre-tension the seat-belt.
• FIGURE 1 is a schematic side view of one form of seat belt pre-tensioner in accordance with the invention
• FIGURE 2 is a plan view of the pre-tensioner of Figure 1 ,
• FIGURE 3 is a schematic view in section along the line A-A in Figure 1 in one position of the apparatus
• FIGURE 4 is a view similar to Figure 3 but showing another position of the apparatus
• FIGURE 5 is a view in section along the line B-B in Figure 2
• FIGURE 6 is a side view of an alternative form of seat belt pre-tensioner in accordance with the invention.
• FIGURES 7A, 7B, 7C and 7D illustrate respective positions of a restraining arrangement used in the apparatus of Figure 6.
• the seat-belt pre-tensioner illustrated is operable either pneumatically or pyrotechnically and has a first inlet 20 connected, through a pneumatic line, (not shown), to a pressurized gas reservoir, (not shown), via a control valve (not shown) and has a second inlet 22 connected with a pyrotechnic gas generator (not shown) of a kind known per se.
• the apparatus of Figures 1 to 5 comprises a prime mover or motor 24 comprising a rotary piston or vane 28 moveable around a cylindrical chamber by pneumatic pressure or pyrotechnic gas pressure.
• the cylindrical chamber is formed in a block 26 and the rotary piston or vane 28 has a radially inner end fixed to or integral with a shaft 30 which extends axially through the chamber and extends sealingly through respective bores through respective end plates at axially opposite axial ends of the block or chamber, which end plates, together with the block 26 define the working chamber for the piston or vane 28.
• a fixed blocking member 34 within the chamber extends from the peripheral cylindrical wall of the chamber to the shaft 30 which is rotatable but sealed with respect to the member 34.
• the member 34 and the piston 28 are in sealing engagement with the peripheral wall of the chamber at their radially outer ends and with the inner surfaces of the end plates at the axially extreme edges of the member 34 and piston 28, so that the member 34 and piston or vane 28 together define, within the cylindrical chamber, a first chamber part 38 into which the inlets 20 and 22 open and a second chamber 40 from which an exhaust port 42 normally extends.
• Figure 3 shows the initial position or normal position of the vane 28 within the chamber.
• the arrangements of the ports 20, 22 and 42 are such that, as viewed in Figure 3, the vane 28 is always further clockwise than the inlets 20 and 22 whilst the exhaust port 42 remains further clockwise than the vane 28, and thus within the chamber 40, during displacement of the vane 28 under pressure in chamber part 38, until close to the end of that displacement at which point the vane 28 passes the exhaust port 42 allowing the gases in the chamber part 38 to escape.
• the upper end of the shaft 30 carries a radially extending arm 50 from the radially outer end of which extends upwardly a shaft 52 on which a pulley 54 is rotatably mounted.
• the motor block is fixed in a bracket 45, fixed to the body of the vehicle, for example to the floor of the vehicle.
• the bracket 45 is U- shaped, providing a lower horizontal limb extending below the motor 24 and having a vertical bore receiving a lower end of shaft 30.
• the bracket 45 has an upper horizontal limb extending over the arm 50 and pulley 54 and having an arcuate slot 56 through which the upper end of the shaft 52 extends and the edges of which help to support the shaft 52 during the movement of the lever 50 and vane 28 described and the consequent movement of the lever 50.
• valve in the pneumatic line connected with port 20 will first be opened as a result of a predictive crash sensor being triggered, causing pressurized air or other gas to enter the chamber 38 and begin to move the vane 28 clockwise in Figures 3 and 4. If the emergency situation develops into an actual crash, the pyrotechnic gas pressure generator connected with the inlet 22 will be triggered, driving the vane 28 further clockwise towards and through the position illustrated in Figure 4 until finally the vane 28 passes the exhaust port 42, allowing the gas from chamber 38 to escape, before the vane 28 is prevented from further movement by the element 28.
• a cable loop 56 is extended around the pulley 54 and extends from the pulley 54 under a guide member or pulley 58 to the lower end of a seat-belt fitting 60, which may, for example, carry at its upper end a seat belt buckle adapted to receive a complementary portion of a buckle part through which an associated seat belt runs in known fashion.
• the guide member or pulley 58 is mounted in a bracket 59 fixed to the body of the vehicle, for example to the floor of the vehicle.
• a variant pre-tensioner is shown which is operated by a conventional piston and cylinder unit 100 comprising a single acting piston 102 displaceable axially within a cylinder 104 in response to pressurised gas supplied to an inlet 20 connected, via a pneumatic line incorporating a sensor-operable valve with a pressurised gas reservoir (not shown) containing, for example, compressed air.
• the cylinder 104 is likewise connected via an inlet 22 with a pyrotechnic gas generator (not shown).
• the inlets 20, 22 connect with one end of the cylinder, the piston 102 normally being disposed adjacent that one end and being displaceable towards the opposite end by gas pressure supplied via inlet 20 or 22.
• a piston rod 106 extends from the piston 102 through said other end of the cylinder and carries at its outer end a bearing member 108 which receives rotatably a journal pin 110 extending from one side of a drum 112. Said one end of the cylinder is closed by a cap 114 having an apertured lug by means of which the cylinder is pivotally mounted on a pin 120 carried by a bracket 122 bolted to the bodywork of the vehicle, for example to the floor of the vehicle.
• the drum 112 is rotatable in the bracket 122 around the axis of a shaft 124 which is eccentrically located with respect to the drum 112, the axis of shaft 124 thus extending parallel with the central axis of the drum 112 but being displaced radially from that axis.
• the drum 112 has a peripheral groove, indicated in broken lines in Figure 6, which serves to guide a cable 130 which is secured at one end at 132 to the bracket 122 and which extends under the drum 112 and runs partially around the drum through an arc of approximately 90° when it extends upwardly to a seat buckle 140.
• the groove around the drum serves to guide the cable 130 but additional means, not shown, may be provided to ensure that the cable 130, in normal use, remains in the groove.
• the buckle 140 or the upper part of the cable is biased upwardly by means not shown, so that the cable 130 is drawn tightly against the drum.
• a ratchet segment 150 fixed to the drum shaft 124 cooperates with a pawl 152 pivotally mounted on the bracket 122.
• the pawl 152 is spring biased into engagement with the ratchet and operates to ensure that the seat-belt, once pre-tensioned, remains so until the apparatus is re-set manually.
• Figure 7A shows positions of the ratchet segment and pawl in a so-called presenter phase in which the seat belt arrangement is placed in readiness for fitting around a seat occupant and securing
• Figure 7B shows the position of normal use once the seat belt has been secured around the occupant of the respective seat
• Figure 7C shows the position after pre-tensioning by the compressed gas or pneumatic source alone
• Figure 7D shows the position after pre-tensioning by the pyrotechnic device.
• a similar ratchet and pawl arrangement may be provided, for the same purpose, in the apparatus of Figures 1 to 5, the ratchet being secured to the shaft 30 and the pawl being mounted on the bracket 45, for example.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Automotive Seat Belt Assembly (AREA)

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• 2007
  • 2007-09-10 EP EP07835039A patent/EP2185387A4/de not_active Withdrawn
  • 2007-09-10 WO PCT/SE2007/000780 patent/WO2009035379A1/en active Application Filing

Non-Patent Citations (2)

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