RESTRAINT SYSTEM OF A SEAT BELT RETRACTOR ASSEMBLY

Abstract

A restraint system (30) comprising: a housing (32); a spool (34) rotatably connected to the housing (32); a cutter (38) movable along a path from a spaced position spaced from the spool (34) to a cutting position adjacent the spool (34); a plate (40) movable between an engaged position extending in the path and a disengaged position spaced from the path; and an actuator (42) connected to the plate (40).

Description

[0001] The invention relates to a restraint system of a safety belt retractor assembly in a vehicle. BACKGROUND

[0002] A seat belt may be equipped with "load-limiting" features. During a collision, a seat belt retractor may lock the seat belt webbing to prevent it from being further pulled out of the retractor, but load-limiting features allow some additional limited stretch of the webbing when the force applied to the webbing exceeds a load-limiting threshold.

[0003] The document DE 10 2007 026 128 A1 describes a restraint system comprising a housing, a rotatable spool connected to the housing, a cutting device movably connected to the housing, an actuating element connected to the housing, a plate-shaped lever which is movably connected to the actuating element from an engaged position next to the cutting device to a disengaged position at a distance from the cutting device, and a sensor in connection with the actuating element.

[0004] Different load limit thresholds could apply to different types of vehicle occupants. A relatively low load limit mode, meaning a lower threshold force before belt webbing stretches, might apply to adults. On the other hand, a relatively high load limit mode might apply to an infant or toddler in a child car seat installed on the vehicle seat, in which case the child car seat would be positioned more firmly on the vehicle seat.

[0005] Another seat belt feature that can be helpful for child car seats is an automatic locking retractor. When an automatic locking retractor is engaged, the seat belt webbing can retract but not extend. The seat belt webbing can then hold the child car seat more securely in the vehicle seat.

[0006] The task is to provide a restraint system for child seats that is safe compared to the state of the art.

[0007] This object is achieved by a restraint system having the features according to claim 1 and claim 12. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a vehicle seat with a restraint system in a vehicle. Fig. 2 is a perspective view of a portion of the restraint system. Fig. 3 is an exploded view of a retractor assembly of the restraint system. Fig. 4 is a perspective view of a spool of the take-up assembly. Fig. 5 is a plan view of an automatically locking retractor system of the retractor assembly. Fig. 6 is a side view of a slotted member and cutter of the take-up assembly with a cut-out portion of the spool. Fig. Figure 7 is a plan view of the slotted member, the cutting device, and a plate in a disengaged position of the retention system. Fig. Figure 8 is a plan view of the slotted member, cutter, and plate in an engaged position of the retention system. Fig. 9 is a block diagram of a control system of the restraint system. Fig. 10 is a process flow diagram of the restraint system. DETAILED DESCRIPTION

[0008] Referring to the figures, wherein like numbers indicate like parts throughout the several views, a restraint system 30 includes a housing 32, a spool 34, a disc 36, a cutter 38, a plate 40, and an actuator 42. The spool 34 is rotatably connected to the housing 32. The disc 36 is fixed to the spool 34. The cutter 38 is movable along a path P from a position spaced from the disc 36 to a cutting position adjacent the disc 36. The plate 40 is movable between an engaged position extending into the path P and a disengaged position spaced from the path P. The actuator 42 is connected to the plate 40.

[0009] The restraint system 30 provides redundancy to maintain the restraint system 30 in a high load limiting state, for example, when an automatically locking retractor 44 is in an engaged state, as further discussed below. When the cutter 38 is in the cutting position, the cutter 38 raises the load limiting threshold. The plate 40 helps ensure that the cutter 38 does not slip out of the cutting position. On the other hand, the plate 40 can move to the disengaged position, allowing the cutter 38 to move to a spaced-apart position relative to the disc 36 and placing the restraint system 30 in a low load limiting state, which may be more appropriate, for example, when the automatically locking retractor 44 is in a disengaged state.

[0010] With reference to Fig. 1, a vehicle 46 has a seat 48 that can support a vehicle occupant 50. The seat 48 can be a front seat or a rear seat and can be located in any transverse direction of the vehicle. Fig. The seat 48 shown in Figure 1 is a bucket seat, but the seat 48 may alternatively be a bench seat or other type of seat. The vehicle occupant 50 may be an adult or juvenile, or alternatively, it may be a child car seat for supporting an infant or toddler.

[0011] The restraint system 30 may include a retractor assembly 54, a belt webbing 52 retractably unrolled from the retractor assembly 54, a lap belt attachment 56 connected to the belt webbing, and a buckle tongue 58 engaging a belt buckle 60. The restraint system 30 holds the vehicle occupant 50 in the seat 48 after buckling, e.g., during sudden braking of the vehicle 46.

[0012] The retractor assembly 54 may be attached to a (unnumbered) structure of the vehicle 46, e.g., to a B-pillar 62 if the seat 48 is a front seat, a C-pillar (unnumbered) if the seat 48 is a rear seat, etc. The retractor assembly 54 may alternatively be attached to the seat 48.

[0013] The lap belt attachment 56 secures one end of the webbing 52 to the seat 48. The other end of the webbing 52 is guided into the retractor assembly 54. The buckle tongue 58 slides freely along the webbing 52 and, when engaged with the buckle 60, divides the webbing 52 into a lap belt webbing 64 and a shoulder belt webbing 66.

[0014] The restraint system 30 from Fig. 1 is a three-point belt, ie the belt webbing 52 is attached to the vehicle occupant 50 at three points after buckling: the lap belt attachment, the retractor assembly 54 and the belt buckle 60. The restraint system 30 may alternatively have a different arrangement of attachment points.

[0015] The retractor assembly 54 may be contained within the housing 32. The housing 32 may include a housing body 80 and a housing cover 82 secured to the housing body 80. The housing 32 may be made of metal or plastic. The housing 32 may be secured to a (unnumbered) structure of the vehicle 46, e.g., to a B-pillar 62 if the seat 48 is a front seat, a C-pillar (unnumbered) if the seat 48 is a rear seat, or it may be attached to the seat 48.

[0016] With reference to the Fig. 3 and Fig. 4, the spool 34 is rotatably mounted on the housing 32. The spool 34 can rotate freely relative to the housing 32. The spool 34 can be cylindrical. The spool 34 can define an axis of rotation R about which the spool 34 rotates. The spool 34 can be configured to receive the webbing 52, for example, by having a webbing attachment slot 84 and allowing the webbing 52 to wind around the shaft 86 of the spool 34.

[0017] The webbing 52 may be attached to the spool 34. Specifically, one end of the webbing 52 may be attached to the lap belt attachment 56, and another end of the webbing 52 may be attached to the spool 34, with the webbing 52 wrapping around the spool 34 starting at that end. The webbing 52 may be formed from a textile material in the shape of a strap.

[0018] With reference to Fig. 3, a retractor spring 78 may extend from the housing 32 to the spool 34. The retractor spring 78 may be loaded into tension or compression when the webbing 52 is fully retracted, and the retractor spring 78 may further be loaded into either tension or compression when the webbing 52 is withdrawn from the spool 34. The retractor spring 78 may thus exert a force tending to retract the webbing 52. The retractor spring 78 may be a coil torsion spring or any other suitable type of spring.

[0019] With reference to Fig. 4, the disc 36 may be fixed to the spool 34. In particular, the disc 36 may be fixed to one end of the spool 34 and rotate with the spool 34 about the rotation axis R. The disc 36 may be integral with the shaft 86, i.e., it may be molded simultaneously with the shaft 86 as a single continuous unit. Alternatively, the disc 36 may be molded separately and subsequently attached to the shaft 86. The disc 36 may have a circular shape. The disc 36 may be made of metal or plastic.

[0020] The disc 36 may include a circular tapered strip 88, also referred to as a tab, which is radially aligned with the cutting device 38 with respect to the disc 36. In other words, the strip 88 may be disposed at the same distance from the axis of rotation R as the cutting device 38. The strip 88 may extend in a circle centered on the axis of rotation R. The strip 88 may progressively increase in width and / or depth from a starting point around the circle to an end point, which may be located at the starting point. The strip 88 may be integral with the disc 36, that is, it may be molded simultaneously with the disc 36 as a single continuous unit. Alternatively, the strip 88 may be molded separately and subsequently attached to the disc 36.

[0021] With reference to Fig. 5, the automatic locking retractor 44 may be connected to the spool 34. An automatic locking retractor cover 118 may be attached to the housing and cover the automatic locking retractor 44.

[0022] The automatically locking retractor 44 can move between an engaged state (not shown) and a disengaged state, as shown in Fig. 5. The automatic locking retractor 44 can move into the engaged state when the webbing 52 is fully withdrawn from the spool 34. In the disengaged state, the automatic locking retractor 44 allows free rotation of the spool 34 so that the webbing 52 can extend from the spool 34. In the engaged state, the automatic locking retractor 44 prevents rotation of the spool 34 in one direction so that the webbing 52 can retract but cannot be withdrawn. The automatic locking retractor 44 may include a cam 90 or a lever 92 or other suitable mechanism.

[0023] Furthermore, with reference to Fig. 5, the cam 90 may be fixed to the spool 34. The cam 90 may rotate about the rotation axis R with the spool 34. The cam 90 may have a base surface 94 and a cam surface 96. The base surface 94 and the cam surface 96 may follow circular arcs about the rotation axis R. The cam surface 96 may have a larger radius of curvature than the base surface 94.

[0024] The lever 92 may be attached to the housing 32 and engage the cam 90. The lever 92 may have any structure configured to pivot with respect to the housing 32. For example, the lever 92 may be attached to the housing 32 via a fastener 98. The lever 92 may pivot with respect to the housing 32, with the fastener 98 serving as a pivot point. Additionally, the lever 92 may have an arm 100 configured to engage the cam 90. Alternatively, the lever 92 may engage the cam 90 without the arm 100. The lever 92 may have a position that depends on whether the lever 92 engages the base surface 94 or the cam surface 96 of the cam 90. Rotation of the cam 90 may result in a change in the position of the lever 92.

[0025] With reference to Fig. 3, a torsion bar 70 may be connected to the auto-locking retractor 44 and to the spool 34. The torsion bar 70 may be designed to provide rotational compliance, e.g., plastically deform, when the torsion bar 70 is rotated by the spool 34 but is fixed by the auto-locking retractor 44. In particular, the torsion bar 70 may be formed with a suitable shape, dimension, and material to provide compliance when subjected to a threshold rotational force. When the auto-locking retractor 44 is engaged but the webbing 52 applies a rotational force to the spool 34, the torsion bar 70 may prevent rotation of the spool 34 unless the force exceeds a threshold, in which case the rotational compliance may permit rotation of the spool 34. The force held by the belt strap 52 can thus be limited.

[0026] With reference to Fig. 6, the cutting device 38 may be movably connected to the housing 32. The cutting device 38 may be movable along the path P from a spaced position (not shown) at a distance from the disc 36 to a cutting position adjacent the disc 36, as shown in Fig. 6. The cutter 38 may be disposed in the spaced-apart position when the auto-locking retractor 44 is in the disengaged state, and may move to the cutting position when the auto-locking retractor 44 is in the engaged state. In the spaced-apart position, the cutter 38 may be disposed at a distance from the pulley 36, thus avoiding contact with the pulley 36 as the pulley 36 rotates. In the cutting position, the cutter 38 may be adjacent to the pulley 36 so that there is nothing between the cutter 38 and the pulley 36. As the pulley 36 rotates while the cutter 38 is in the cutting position, the cutter 38 may cut material from the strip 88 from the pulley 36, thus resisting the rotation of the pulley 36 and the spool 34 and increasing the load limit.In particular, the cutting device 38 can be aligned with the strip 88 in the cutting position and cut on the strip 88 as the disk 36 rotates.

[0027] The cutting device 38 may include a cutting element 102 and a wedge 104. The cutting element 102 and the wedge 104 may be integral, rigidly mounted, or movably mounted.

[0028] The cutting element 102 may have a cutting surface 106 directed toward the disk 36. The cutting device 38, or at least the cutting surface 106, may be made of a material that is harder than the material forming the disk 36.

[0029] A slotted member 76 may be connected to the housing 32. In particular, the slotted member 76 may be fixed relative to the housing 32 so that the slotted member 76 does not rotate with the spool 34 and the disc 36. The slotted member 76 may be disposed adjacent to the disc 36.

[0030] With reference to the Fig. 7 and Fig. 8, the slotted member 76 may include a slot 108 disposed along path P. The slot 108 is positioned to receive the cutting device 38. The slot 108 may have a width and a length, and the width may be narrower than the length.

[0031] The cutting device 38 may include the wedge 104. The wedge 104 may be aligned with the slot 108 when the cutting device 38 is in the cutting position, as shown in Fig. 8, and it can no longer be aligned with the slot 108 when the cutting device 38 is in the spaced-apart position as shown in Fig. 7. In particular, the wedge 104 may have a width and a length, and the width may be narrower than the length. The width of the wedge 104 may be shorter than the width of the slot 108, and the length of the wedge 104 may be shorter than the length of the slot 108 but longer than the width of the slot 108. The wedge 104 may thus fit through the slot 108 when the length of the wedge 104 is aligned with the length of the slot 108, but not when the length of the wedge 104 is no longer aligned with the length of the slot 108.

[0032] With reference to Fig. 6, a spring 72 may extend from the slotted member 76 to the cutting device 38. The spring 72 may be a coil spring or any other suitable type of spring. The spring 72 may be loaded in compression so that the spring 72 tends to push the cutting device 38 from its spaced-apart position to the cutting position.

[0033] The spool 34 may include a mounting disk 74 connected or secured to the housing 32. The mounting disk 74 may retain the cutter 38 and spring 72 relative to the spool 34.

[0034] With reference to Fig. 9, a control system 110 may include a sensor 112, a control unit 114, and the actuator 42. The sensor 112 may communicate with the control unit 114 by sending a signal to the control unit 114. The control unit 114 may communicate with the actuator 42 by sending a signal to the actuator 42. The sensor 112 may communicate with the actuator 42, either directly or indirectly via the control unit 114.

[0035] With reference to the Fig. 3 and Fig. 5, the sensor 112 can be fixed with respect to the housing 32. The sensor 112 can be configured to detect at least the engaged state and / or the disengaged state of the automatically locking retractor 44. In particular, the sensor 112 can be positioned to detect a position of the lever 92 with respect to the housing 32. For example, the sensor 112 can be a Hall-effect sensor, which is a transducer that changes an output voltage in response to a magnetic field. Accordingly, the lever 92 can include a magnetic field generator 116, e.g., a permanent magnet, disposed on the lever 92 and moving with the lever 92. The Hall-effect sensor 112 can detect the position of the lever 92 with respect to the housing 32 through the proximity of a magnetic field generated by the magnetic field generator 116.Alternatively, the sensor 112 may be any other suitable sensor capable of detecting the position of the lever 92 or the state of the automatically locking retractor 44.

[0036] The control unit 114 may be a microprocessor-based control unit. The control unit 114 may include a processor, memory, etc. The memory of the control unit 114 may store instructions that can be executed by the processor.

[0037] The control unit 114 may be in communication with the sensor 112 and the actuator 42. The control unit 114 may be programmed to instruct the actuator 42 to move the plate 40 based on a signal from the sensor 112. The control unit 114 may receive a signal from the sensor 112 indicating that the automatically locking retractor 44 is in the engaged state, and the control unit 114 may then send a signal to the actuator 42 to move the plate 40.

[0038] With reference to the Fig. 7 and Fig. 8, the actuator 42 may be connected to the housing 32 and to the plate 40. The actuator 42 may receive a signal from the control unit 114 or directly from the sensor 112. The actuator 42 may be any suitable device for moving the plate 40. For example, the actuator 42 may be a solenoid.

[0039] The plate 40 may be movably connected to the actuating element 42. The plate 40 may be movable between a disengaged position, which is Fig. 7, and an intervention position shown in Fig. 8 can be seen, be movable. In the Fig. 8, the plate 40 can extend into the path P, partially covering the slot 108 and lying next to the cutting device 38; in the position shown in Fig. 7, the plate 40 may be spaced apart from the path P, away from the slot 108, and spaced apart from the cutter 38. Thus, when the cutter 38 is in the cutting position and the wedge 104 of the cutter 38 is disposed in the slot 108, the plate 40 may prevent movement of the cutter 38 out of the cutting position by blocking movement of the wedge 104 out of the slot 108. While the spring 72 may also maintain the cutter 38 in the cutting position, the plate 40 provides a redundant fail-safe to maintain the cutter 38 in the cutting position. The plate 40 may be any suitable barrier that prevents the wedge 104 from moving out of the slot 108.

[0040] With reference to Fig.10, the restraint system 30 may begin in operation with the webbing 52 fully retracted, the automatically locking retractor 44 in the disengaged position, the cutter 38 in the spaced-apart position, and the plate 40 in the disengaged position at block 1002. The vehicle occupant 50 may extend the webbing 52 at block 1004. The webbing 52 may or may not be fully extended at decision block 1006. The vehicle occupant 50 may only partially extend the webbing 52 if, for example, the vehicle occupant 50 is an adult sitting in the seat 48; or the vehicle occupant 50 may fully extend the webbing 52 from the spool 34 if, for example, the vehicle occupant 50 is installing a child car seat.If the webbing 52 is not fully extended, the auto-locking retractor 44 remains in the disengaged state, at block 1008, and the system does nothing until the webbing 52 is next extended. When the webbing 52 is fully extended from the spool 34, the auto-locking retractor 44 assumes that a child seat is present and switches to the engaged state, at block 1010, i.e., the spool 34 allows the webbing 52 to be retracted but not extended. The sensor 112 detects the state of the auto-locking retractor 44; For example, cam 90 rotates so that lever 92 engages cam surface 96, and sensor 112 detects the increased spacing of magnetic field generator 116 on lever 92 in block 1012. Sensor 112 sends a signal to control unit 114 in block 1014.The control unit 114 signals the cutter 38 to move from the spaced position to the cutting position, and the control unit 114 signals the actuator 42 to move the plate 40 in block 1016. The cutter 38 moves to the cutting position in block 1018. The actuator 42 moves the plate 40 from the disengaged position to the engaged position in block 1020. The plate 40 is now positioned to prevent the cutter 38 from inadvertently moving from the cutting position.When the webbing 52 has been fully retracted onto the spool 34, the restraint system 30 returns to the initial state at decision block 1022, with the webbing 52 fully retracted, the automatically locking retractor 44 in the disengaged state, the cutter 38 in the spaced-apart position, and the plate 40 in the disengaged position.

[0041] If the vehicle 46 is involved in a collision when the restraint system 30 is in the initial position, an emergency locking retractor system (not shown) may engage and prevent the forward momentum of the vehicle occupant 50 from extending the webbing 52. The torsion bar 70 resists the torque on the spool 34. When the force exerted by the vehicle occupant 50 on the webbing 52 exceeds a threshold value for the torsion bar 70, the torsion bar 70 releases, allowing the spool 34 to rotate and extend the webbing 52 a distance. The cutter 38 is in the disengaged position and thus does not impede the rotation of the spool 34.

[0042] If the vehicle 46 is involved in a collision when the auto-locking retractor 44 is in the engaged state, the auto-locking retractor 44 prevents the forward momentum of the vehicle occupant 50 from freely rotating the spool 34 and extending the webbing 52. The cutter 38 is in the cutting position and the plate 40 is in the engaged position. The torsion bar 70 resists the torque on the spool 34. When the force exerted by the vehicle occupant 50 on the webbing 52 exceeds the threshold for the torsion bar 70 and the torsion bar 70 begins to rotationally yield, the cutter 38 further cuts into the material on the disk 36, further resisting rotation of the spool 34. The cutter 38 engages the circular tapered strip 88 on the disk 36.Since the cross-sectional area of the strip 88 increases as the pulley 36 rotates, the resistive force from the material-cutting cutter 38 increases accordingly. This increasing resistive force is called progressive load limiting. The total resistive force from the torsion bar 70 and the cutter 38 in the cutting position is greater than the resistive force from the torsion bar 70 alone. The force that must be exerted by the webbing 52 before the webbing 52 is extended is thus greater when the auto-locking retractor 44 is in the engaged state than when it is in the disengaged state. The restraint system 30 is in a higher load limiting scheme when the auto-locking retractor 44 is engaged than when it is in the disengaged state.

Claims

[1] Restraint system (30) comprising: a housing (32); a coil (34) rotatably connected to the housing (32); a cutting device (38) movable along a path from a spaced position spaced from the spool (34) to a cutting position adjacent the spool (34); a plate (40) movable between an engagement position extending in the path and a disengaged position is movable at a distance from the path; and an actuating element (42) connected to the plate (40). [2] The restraint system (30) of claim 1, wherein the actuating element (42) is a solenoid. [3] The retention system (30) of claim 1 or 2, further comprising a slotted member connected to the housing (32) and having a slot (108) disposed on the path, the slot (108) positioned to receive the cutting device (38). [4] The retention system (30) of claim 3, wherein the cutting device (38) includes a wedge (104), and the wedge (104) is aligned with the slot (108) when the cutting device (38) is in the cutting position and is no longer aligned with the slot (108) when the cutting device (38) is in the spaced-apart position. [5] The restraint system (30) of claim 3 or 4, wherein the plate (40) partially covers the slot (108) in the engaged position and the plate (40) is located away from the slot (108) in the disengaged position. [6] The retention system (30) of any one of claims 3 to 5, further comprising a spring (72) extending from a slotted member (76) to the cutting means (38). [7] Restraint system (30) according to one of claims 1 to 6, further comprising a Hall effect sensor (112) in communication with the actuating element (42). [8] Restraint system (30) according to one of claims 1 to 7, further comprising: an automatically locking retractor (44) connected to the spool (34) and moving between an engaged state and a disengaged state; and a sensor (112) connected to the actuating element (42) and designed to detect at least the engaged state and / or the disengaged state of the automatically locking retractor (44). [9] The restraint system (30) of claim 8, further comprising a webbing (52) attached to the spool (34), wherein the automatically locking retractor (44) moves into the engaged state when the webbing (52) is fully extended. [10] Restraint system (30) according to one of claims 1 to 9, further comprising: a cam (90) attached to the spool (34); a lever (92) mounted on the housing (32) and engaging the cam (90); and a sensor (112) connected to the actuating element (42) and positioned to detect a position of the lever (92) relative to the housing (32). [11] The restraint system (30) of any one of claims 1 to 10, wherein the spool (34) includes a circular tapered strip (88) aligned with the cutting means (38) radially relative to the spool (34). [12] Restraint system (30) comprising: a housing (32); a coil (34) rotatably connected to the housing (32); a cutting device (38) movably connected to the housing (32); an actuating element (42) connected to the housing (32); a plate (40) movably connected to the actuating element (42) from an engaged position adjacent to the cutting device (38) to a disengaged position spaced from the cutting device (38); and a sensor (112) in connection with the actuating element (42), characterized by , that the cutting device (38) is movable along a path from a spaced position spaced from the spool (34) to a cutting position adjacent the spool (34), further comprising a slotted member (76) connected to the housing (32) and having a slot (108) disposed on the path, the slot (108) being positioned to receive the cutting device (38). [13] The restraint system (30) of claim 12, further comprising an automatically locking retractor (44) connected to the spool (34) and moving between an engaged state and a disengaged state, wherein the sensor (112) is configured to detect at least one of the engaged state and the disengaged state of the automatically locking retractor (44). [14] The restraint system (30) of claim 12 or 13, further comprising a control unit (114) in communication with the sensor and the actuator (42), the control unit (114) being programmed to instruct the actuator (42) to move the plate (40) based on a signal from the sensor (112). [15] The restraint system (30) of claim 13, further comprising a webbing (52) attached to the spool (34), wherein the automatically locking retractor (44) moves into the engaged state when the webbing (52) is fully extended. [16] The retention system (30) of claim 15, wherein the cutting device (38) includes a wedge (104), and the wedge (104) is aligned with the slot (108) when the cutting device (38) is in the cutting position and is no longer aligned with the slot (108) when the cutting device (38) is in the spaced-apart position. [17] A restraint system (30) according to claim 15 or 16, wherein the plate (40) partially covers the slot (108) in the engaged position and the plate (40) is arranged away from the slot (108) in the disengaged position. [18] The retention system (30) of any one of claims 15 to 17, further comprising a spring (72) extending from the slotted member (76) to the cutting means (38). [19] The restraint system (30) of any one of claims 12 to 18, further comprising a cam (90) attached to the spool (34) and a lever (92) attached to the housing (32) and engaging the cam (90), the sensor (112) being positioned to detect a position of the lever (92) relative to the housing (32).

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