JPH0722869U - Seat belt retractor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a good seat belt retractor capable of absorbing collision energy by increasing the winding amount of the webbing wound on the take-up reel without increasing the output of the take-up spring. To do. [Structure] Inertia sensing means according to webbing winding state
The control plate 22 rotates the engaging projection 23a of the lever 23, which is capable of following the engaging position of the pole 11 with respect to the latch plate 4a by activating 31 and rotating in response to the rotation of the winding shaft 4.
Engage with the cam groove of. When the webbing is pulled out by a predetermined amount, the lever 23 swings following the cam surface of the cam groove and activates the inertia sensing means 31, so that the rotation of the winding shaft 4 in the webbing pulling-out direction is prevented. Therefore, even if the webbing remains unwound on the take-up reel, the webbing cannot be pulled out any more, and the usable rotation range of the take-up spring increases even if the amount of webbing wound on the take-up reel is increased in advance. There is no.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a seat belt retractor used in an automobile or the like, and more specifically, when a tension of a predetermined magnitude or more is applied to the seat belt due to the impact of a collision, the seat belt is unrolled to the occupant's body. The present invention relates to a seat belt retractor that reduces the deceleration that acts on it and can protect the occupant more effectively.

[0002]

[Prior art]

 Conventionally, a seat belt device is used to protect the occupant from the impact of a collision by restraining the occupant of the vehicle in the seat, but as a webbing retractor (retractor) that constitutes this seat belt device. Is equipped with an emergency locking mechanism that physically locks the retractor rotation by inertial sensing means that responds to sudden acceleration, collision or deceleration, effectively and safely restraining the occupant and reducing the feeling of pressure from the webbing. An emergency locking retractor is used.

Further, in such a retractor, not only an emergency locking mechanism for locking the rotation of the winding shaft around which the webbing is wound in the webbing pull-out direction in the event of a vehicle emergency such as a collision but also the webbing Some models have a belt clamp mechanism that directly sandwiches the vehicle to stop the seat belt from extending, improving the occupant restraint performance in the initial stage of a collision.

However, in a vehicle emergency such as a collision, it is conceivable that a force greater than the breaking strength of the webbing clamped by the belt clamp mechanism acts on the webbing. That is, when a strong pulling force that further pulls out the webbing is applied to the retractor in which the seat belt is prevented from being stretched by the belt clamp mechanism as described above, the webbing holding portion tries to hold the webbing more strongly. The force that acts on the webbing is concentrated, and the webbing may be broken at this sandwiching part. Further, when the impact force due to the collision is extremely large, the occupant's body is suddenly decelerated, and as a result, the load on the occupant by the seat belt may increase.

Therefore, by improving the above-described belt clamp mechanism, the belt clamp mechanism is operated to keep the seat belt unwound in the initial stage when the tension applied to the seat belt due to an impact is smaller than a predetermined value. , The occupant's body is securely restrained to the seat, and when the tension acting on the seat belt exceeds a predetermined value, the belt clamp mechanism is deactivated and the seat belt is unwound by a predetermined amount. A belt clamp mechanism that alleviates the deceleration that occurs in the body is disclosed in Japanese Patent Laid-Open No. 4-252761.

On the other hand, in order to alleviate the deceleration that occurs in the body of the occupant, the amount by which the seat belt is unwound when a tension of a predetermined value or more acts on the belt is, for example, when the body of the occupant moves too much forward. It is preferable that it is within a range where it does not hit the steering wheel or the like and a large load due to bending of the body is not applied, because the larger the amount, the more the absorption of impact energy increases.

[0007] Thus, various proposals have been made to increase the amount of unwinding of the seat belt, but the simplest method is to increase the amount of webbing wound around the take-up reel that winds the seat belt. Is common. In this method, when the take-up shaft is locked against rotation in the webbing pull-out direction and strong tension acts on the seat belt due to the impact of collision, the webbing wound on the take-up reel is tightened. The fact that the collision energy is absorbed when the diameter is reduced is utilized, and the amount of winding of the webbing is increased by the amount of increase of the amount of winding, and the amount of unwinding of the seat belt can be increased.

[0008]

[Problems to be solved by the device]

 By the way, in the case of a seatbelt retractor capable of absorbing collision energy by increasing the winding amount of the webbing as described above, in order to obtain the amount of extension of the seatbelt sufficient to absorb the collision energy, The winding amount of the webbing must be considerably increased, and naturally, the number of rotations of the winding shaft required for the retractor from the fully wound state to the fully wound state is also increased.

However, since the retractor as described above is configured to wind up and store the webbing on the take-up reel driven by the take-up spring when the seat belt device is not used, after releasing the clamp. If the winding amount of the webbing wound around the take-up reel is increased in order to increase the seat belt unwinding length, the range in which the take-up spring can be used is expanded and the conventional take-up spring cannot be used. Therefore, it is necessary to use a take-up spring that has a wide range of rotation and has a strong take-up force. There are problems that the operation force when pulling out the webbing for wearing the seat belt increases and that the retracting spring becomes large and the retractability of the retractor to the vehicle body deteriorates.

Therefore, an object of the present invention is to solve the above problems, and it is possible to absorb the collision energy by increasing the winding amount of the webbing wound on the winding reel without increasing the output of the winding spring. To provide a good seat belt retractor.

[0011]

[Means for Solving the Problems]

 The above object of the present invention is to provide a rotation lock means capable of engaging with a winding shaft of a retractor that winds a webbing and locking the rotation of the winding shaft in the webbing pull-out direction, and the rotation locking means in case of a vehicle emergency. A retractor for a seat belt having an emergency locking mechanism having an inertial sensing means to be activated, wherein the inertial sensing means is activated in accordance with a webbing winding state, and the rotation lock means is used as a winding shaft. On the other hand, the control means driven according to the engaged position or the non-engaged position can swing between the position for activating the inertia sensing means and the position for not activating the inertia sensing means, and the swing end portion of the transmitting means. A webbing, which is provided with a first guide part and a second guide part that engage with each other to swing the transmission means and that is rotated in response to rotation of the winding shaft. Is a predetermined amount Until the winding shaft is rotated, the swinging end of the transmission means is engaged with the first guide portion of the control panel so that the transmission means does not activate the inertia sensing means, and the webbing is located. The seat belt can be moved to a position where the swinging end of the transmission means is moved to the second guide portion of the control panel so that the transmission means activates the inertia sensing means in the rotation of the winding shaft which is pulled out in a fixed amount. It is achieved by a retractor for the vehicle.

[0012]

[Action]

 According to the above construction, when the webbing is pulled out by a predetermined amount, the swinging end of the transmission means is moved to the second guide portion of the control panel to activate the inertia sensing means, so that the webbing pull-out of the winding shaft is started. Directional rotation is blocked. That is, when the webbing is pulled out by a predetermined amount, even if the remaining webbing is wound around the take-up reel, the webbing cannot be pulled out any more. Therefore, even if the webbing winding amount to be wound around the take-up reel is increased in advance, the use rotation range of the take-up spring during normal use does not increase.

[0013]

【Example】

 An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the exploded perspective views of the seatbelt retractor shown in FIGS. 1 to 3, most of the base 1 has a substantially U-shaped cross section, and the base 1 faces the side plates 1a facing each other, each of which has a through hole. A winding shaft 4 having a winding reel 2 around which webbing is wound is rotatably bridged via left and right plastic bushes 3 in the through hole 1b. A known take-up spring device 5 is arranged at one end of the take-up shaft 4, and the take-up shaft 4 is constantly urged in the webbing take-up direction.

On the other hand, an emergency lock mechanism for preventing the webbing from being pulled out in an emergency is arranged at the other end of the winding shaft 4. This emergency lock mechanism is engaged with the latch plate 4a, which is a ratchet wheel fixed to the other end of the winding shaft 4, and the teeth of the latch plate 4a, whereby the webbing pull-out direction of the latch plate 4a (arrow X ₁ In addition to the rotation lock means composed of a pawl 11 which is a pawl member for restraining the rotation of the rotation direction), the inertia detection means 31 is provided for activating the rotation lock means in case of an emergency of the vehicle.

An end portion of the winding shaft 4 is projected to the outside of the latch plate 4a, and a tension plate 9 and a latch cup 13 which is a latch member are formed in the end portion of the winding shaft 4 so as to constitute the inertia sensing means 31. It is fitted. Incidentally, the return spring 12 in the formed spring hanger 9a to split Nguhanga 13b and the tension plate 9 formed in the latch cup 13 is mounted, the latch cup 13 is action biasing force rotating the direction of arrow X ₂ ing. The take-up shaft 4 located outside the latch cup 13 constitutes a lock means together with a lock member 15 having a lock portion 15a engaging with the inner teeth 13d of the latch cup 13 and a sensor spring 16. The flange 14 is fixed. Further, on the outer side of the lock member 15, there is provided a ratchet wheel 17 which is an inertial member loosely fitted to a tapping screw 20 screwed to the winding shaft 4 via a plane washer 33. A plurality of teeth 17a facing the belt withdrawing direction for engaging with a sensor arm 28 of a vehicle body acceleration sensing means 32 described later are formed on the outer peripheral surface. Further, the friction spring 19 is slidably mounted on the mounting portion provided inside the ratchet wheel 17, and the friction spring 19 is engaged with the lock member 15. The wheel 17 rotates integrally with the winding shaft 4 and can be displaced relative to the winding shaft 4.

Further, a pawl 11 which is engaged with the latch plate 4a to prevent the latch plate 4a from rotating in the webbing pull-out direction (arrow X ₁ direction) is disengaged from the latch plate 4a via the pole pin 10. It is pivotally supported outside the side plate 1a. The pole pin 10 has one end inserted into a through hole 35 formed in the side plate 1a and the other end inserted into a through hole 9b of the tension plate 9 so that the pole 11 and the latch plate 4a mesh with each other. It is prevented from falling due to the load. Therefore, the pole 11 can swing and rotate around the pole pin 10. A pole guide projection 11b is provided on the pole 11 so as to project into the pole guide hole 13c formed on the outer peripheral portion of the latch cup 13.

Further, a sensor case 27 which constitutes a vehicle body acceleration sensing means 32 is fixedly provided under the side plate 1a, and a ball weight 29 which is a sensor is mounted in the hollow portion and a protrusion 28a is provided. A sensor arm 28 included therein is swingably attached. A sensor cover 30 is arranged outside the side plate 1a that covers these emergency lock mechanisms.

As shown in FIG. 3, the support shafts 30 a and 30 b projecting from the inner wall of the sensor cover 30 are provided with an idle gear 21 that meshes with the main gear 18 fixed to the tapping screw 20, respectively. A control plate 22 serving as a control panel that meshes with the small gear of the idle gear 21 and rotates at a reduced speed is rotatably supported. The control plate 22 is formed of synthetic resin, and a cam groove 40 which is a guide portion which constitutes a control means together with a lever 23 and a lock arm 24 which will be described later is appropriately formed on the inner surface thereof.

A lever 23, which is a synthetic resin lever member, is swingably supported on a pivot shaft 25 projecting from the inner wall of the sensor cover 30, and a tip of the lever 23 is a retaining clip. 36 is attached. The lever 23 includes a cylindrical portion 23b that is loosely penetrated by the pivot shaft 25, and a cam arm portion 23c that extends radially outward from the cylindrical portion 23b. An engaging protrusion 23a, which is an engaging portion provided on the swing end of the cam arm portion 23c, is engaged with the cam groove 40 of the control plate 22, and the lever 23 is the cam surface of the cam groove 40. It is swung according to 41 and 42.

Further, on the inner cam surface 23d of the cam arm portion 23c, an engaging projection 24b of a lock arm 24 pivotally supported by a pivot shaft 13a protruding inward of the latch cup 13 is provided. Is capable of engaging through the opening 13f of the latch cup 13. The swinging end of the lock arm 24 is biased in a direction away from the center of rotation of the winding shaft 4 by a torsion coil spring 38 whose one end is locked by a locking piece 13e protruding from the latch cup 13. ing. The lock arm 24, which constitutes a transmission means together with the lever 23, engages with the teeth of the latch plate 4a at the engaging portion 24a thereof as the lever 23 swings, thereby causing the inertia sensing means 31 to operate. The position to be activated, or the position where the engagement portion 24a does not engage with the teeth of the latch plate 4a and does not activate the inertial sensing means 31 (see FIG. 4). The lock arm 24 has its swing range restricted by the opening 13f of the latch cup 13.

As shown in FIG. 5, the cam groove 40 of the control plate 22 has the engaging protrusion 23a of the lever 23 located near the outer periphery of the plate so that the lock arm 24 is not engaged with the latch plate 4a. The cam surface 42, which is the first guide portion for guiding the lever 23 to be positioned, and the engagement protrusion 23a are moved toward the center of rotation of the plate when the webbing is pulled out by a predetermined amount or more, and the lock arm 24 is latched. And a cam surface 41 which is a second guide portion for swinging the lever 23 so as to hold the plate 4a at a position where it engages.

Next, the operation of the seat belt retractor will be described. First, in the fully wound state of the webbing, as shown in FIG. 6B, the engagement protrusion 23a of the lever 23 is positioned at one end of the cam surface 42 of the control plate 22, and the lock arm 24 Is urged by the torsion coil spring 38 in a direction away from the center of rotation of the winding shaft 4, so that the engaging portion 24a does not engage with the teeth of the latch plate 4a as shown in FIG. 6 (a). The latch cup 13 is rotatable relative to the winding shaft 4.

Next, when the webbing starts to be pulled out from the retractor, the winding shaft 4 starts to rotate in the direction of the arrow X ₁ , and the main shaft fixed to the tapping screw 20 that is rotated by the rotation of the winding shaft 4. The gear 18 also starts rotating in the same direction. Then, the control plate 22 is decelerated by the idle gear 21 and starts to rotate in the direction of the arrow Y _1, and the engagement protrusion 23a of the lever 23 follows the cam surface 42. While the engagement protrusion 23a is on the cam surface 42 of the control plate 22, the engagement portion 24a of the lock arm 24 and the teeth of the latch plate 4a do not engage with each other and the inertia sensing means 31 does not operate.

That is, in the normal use range until the webbing is pulled out by a predetermined amount, as shown in FIG. 4, the latch cup 13 has the return spring 12 attached to the spring hanger 13b and the spring hanger 9a of the tension plate 9. The pole 11 is urged in the webbing winding direction (arrow X ₂ direction) by the force, and the pole guide projection 11b engages with the pole guide hole 13c. The pole 11 is urged in a direction not engaged with the latch plate 4a. Further, since the lock portion 15a of the lock member 15 is urged by the urging force of the sensor spring 16 to a position that does not mesh with the inner teeth 13d of the latch cup 13, the webbing can be pulled out freely.

Then, when the webbing is pulled out by a predetermined amount, as shown in FIG. 7B, the engagement protrusion 23a of the lever 23 is pushed by the cam surface 41 and moved toward the center of rotation of the plate. At the same time, the lever 23 is swung in the clockwise direction (arrow W ₂ direction) in FIG. 7. At this time, the cam arm portion 23c urges the lock arm 24 against the urging force of the torsion coil spring 38 in a direction to engage with the latch plate 4a, so that the engaging portion 24a of the lock arm 24 latches. It is engaged with the teeth of the plate 4a.

Then, the webbing is further pulled out from the retractor, and the winding shaft 4 is moved to the arrow X. ₁ When it starts rotating in the direction, the turning force of the winding shaft 4 is transmitted to the latch cup 13 via the lock arm 24 engaged with the latch plate 4a as shown in FIG. Arrow X against the urging force of₁The inertial sensing means 31 rotating in the direction operates. At this time, the pole guide hole 13c that engages with the pole guide protrusion 11b moves the pole 11 through the pole guide protrusion 11b in the direction of arrow Z.₁It rotates in the direction to engage with the latch plate 4a. As a result, the arrow X on the winding shaft 4₁Rotation in the direction, that is, pulling out of the webbing is blocked and locked. In this state, the webbing remains on the take-up reel 2 for several turns.

Further, when the webbing is wound from this state, the control plate 22 starts to rotate in the direction opposite to the arrow Y _1, and the engaging projection 23 a of the lever 23 extends along the cam surface 41 and the outer periphery of the control plate 22. Since the lock arm 24 is urged by the lever 23 in the direction to engage with the latch plate 4a, the lock arm 24 is disengaged from the latch plate 4a. Then, the engagement protrusion 23a slides along the cam surface 42, and the webbing is completely wound while the lock arm 24 is not engaged with the latch plate 4a.

Therefore, even if the webbing remains unwound on the take-up reel 2, if the webbing is pulled out by a predetermined amount, the webbing cannot be pulled out any more. Therefore, even if the amount of webbing wound around the take-up reel 2 is increased, the number of revolutions of the take-up shaft 4 in the webbing pull-out direction from the state where the entire webbing is wound to the state where the webbing is prevented from being pulled out and locked as described above. If the winding speed of the winding spring device 5 is set to be substantially the same as that before the winding amount of the webbing is increased, the rotation range of use of the winding spring of the winding spring device 5 does not increase. In other words, it is not possible to pull out the entire webbing by normal operation, so there is no need to increase the output of the winding spring in order to apply the winding force over the entire length of the webbing with an increased winding amount, and the webbing is not required. It is possible to use the same winding spring as before increasing the winding amount.

That is, the operating force for pulling out the webbing for the occupant to wear the seat belt is increased, and the winding spring is increased in size, so that the retractability of the retractor to the vehicle body is not deteriorated. It is possible to sufficiently increase the winding amount of the webbing to be wound around. When an unillustrated webbing is tensioned in an emergency such as a collision, and when a more than a predetermined impact shocking rotational force in the webbing pull-out direction (arrow X ₁ direction) is applied, the ratchet wheel 17 is operated. Receives an inertial force and causes a rotation delay with respect to the rotation of the winding shaft 4 in the webbing pull-out direction (arrow X ₁ direction). Then, rather than the biasing force of the sensor spring 16, the engaging portion of the friction spring 19 mounted on the mounting portion of the ratchet wheel 17 moves the locking member 15 in the direction in which the locking portion 15a meshes with the internal teeth 13d. When the pushing force is increased, the lock member 15 is moved in the direction in which the lock portion 15a meshes with the inner teeth 13d. Then, the engaging portion 15a of the lock member 15 engages with the inner teeth 13d of the latch cup 13, so that the turning force of the flange 14 is transmitted to the latch cup 13 as shown in FIG. The inertial sensing means 31 which rotates in the direction of the arrow X ₁ against the urging force of the return spring 12 operates. At this time, pawl guide hole 13c that engages the pawl guide projection 11b is engaged with the latch plate 4a by rotating the pawl 11 in the arrow Z ₁ direction via the pawl guide protrusion 11b. As a result, the rotation of the winding shaft 4 in the direction of the arrow X ₁ , that is, the withdrawal of the webbing is blocked, and the emergency lock mechanism operates. When the latch cup 13 is rotated in the direction of the arrow X ₁ , the lock arm 24 pivotally supported by the pivot shaft 13a of the latch cup 13 is also rotated together with the latch cup 13, but the lock arm 24 is It is biased by the torsion coil spring 38 in a direction away from the center of rotation of the winding shaft 4, and does not engage with the latch plate 4a.

When the vehicle is subjected to a speed change more than a predetermined value in an emergency, the ball weight 29 rolls to swing the sensor arm 28, and the tip 28a of the ball weight 29 meshes with the tooth 17a of the ratchet wheel 17. Rotation of the ratchet wheel 17 in the belt withdrawal direction is prevented. If the webbing is further pulled out while the ratchet wheel 17 is prevented from rotating, the ratchet wheel 17 causes a rotation delay with respect to the rotation of the winding shaft 4 in the webbing pull-out direction, so that the locking means 31 operates. Then, the emergency lock mechanism operates as described above, and the drawer of the webbing is locked.

Then, when a strong tension acts on the seat belt due to the impact of a collision while the winding shaft 4 is locked in the rotation of the webbing withdrawal direction, a sufficient winding amount is wound around the winding reel 2. The webbing can absorb collision energy when it is wound and its winding diameter is reduced. Therefore, the seat belt retractor can exert an effective protective function without increasing damage to the body of the occupant.

Further, as another embodiment of the present invention, when the tension acting on the seat belt becomes larger than a predetermined value, the operation of the belt clamp mechanism is released, and the seat belt is fed out by a predetermined amount, so A webbing wound around the take-up reel 2 by providing the seat belt retractor having a known belt clamp mechanism (not shown) having a clamp release mechanism for alleviating the deceleration generated in the body with the control means as in the above embodiment. If the winding amount of the take-up reel can be sufficiently increased, the rotation of the take-up shaft 4 in the webbing pull-out direction is locked by the emergency lock mechanism after the clamp is released, and when the tension of the webbing rises again, the take-up reel 2 is rewound. The degree of deceleration that the wrapped webbing is wound to absorb the collision energy and act on the occupant's body. Can be prevented from changing significantly, and a very effective protection function can be exerted.

The control panel, transmission means, inertial sensing means, and the like in the present invention are not limited to the configuration of the above embodiment, and various modifications can be made based on the gist of the present invention. Needless to say, the emergency lock mechanism can also use various known structures. In the above embodiment, the inertial sensing means 31 is activated by the transmission means engaging with the latch plate 4a. However, for example, the transmission means engages with the ratchet wheel 17 depending on the webbing winding state. , The inertial sensing means 31 may be activated.

[0034]

According to the seat belt retractor of the present invention as described above, when the webbing is pulled out by a predetermined amount, the swing end of the transmission means is moved to the second guide portion of the control panel to cause inertia. Since the sensing means is activated, rotation of the winding shaft in the webbing pull-out direction is prevented. That is, when the webbing is pulled out by a predetermined amount, even if the remaining webbing is wound around the take-up reel, the webbing cannot be pulled out any more.

Therefore, even if the winding amount of the webbing to be wound around the take-up reel is increased in advance, the entire amount of the webbing cannot be pulled out by a normal operation, so that the rotation range of use of the winding spring does not increase. It is not necessary to increase the output of the winding spring in order to apply the winding force over the entire length of the webbing with the increased winding amount. The seatbelt retractor, in which the amount of webbing to be wound around the reel is increased, when the seatbelt device is subjected to a large amount of tension during an emergency, the webbing is tightened and extraly wound around the take-up reel. It can extend for a longer amount, and can alleviate the deceleration that acts on the occupant's body and reliably enhance the occupant's protective function.

Therefore, it is possible to provide a good seat belt retractor capable of absorbing the collision energy by increasing the winding amount of the webbing wound around the winding reel without increasing the output of the winding spring.

[Brief description of drawings]

FIG. 1 is a part of an exploded perspective view of a seat belt retractor according to an embodiment of the present invention.

FIG. 2 is a part of an exploded perspective view of the remaining portion of the seat belt retractor shown in FIG.

FIG. 3 is an exploded perspective view of the remaining portion of the seat belt retractor shown in FIGS. 1 and 2.

FIG. 4 is an enlarged side view of an essential part for explaining the operation of the seat belt retractor shown in FIGS. 1 to 3.

5 is a front view of a lever and a control plate shown in FIG.

FIG. 6A is an enlarged view of an essential part for explaining the operation of the control means, and FIG. 6B is a front view showing an engaged state of the lever and the control plate at this time.

FIG. 7 (a) is an enlarged view of an essential part for explaining the operation of the control means, and FIG. 7 (b) is a front view showing an engaged state of the lever and the control plate at this time.

FIG. 8 is an enlarged view of an essential part for explaining the operation of the control means.

FIG. 9 is an enlarged view of a main part for explaining a webbing drawer lock operation.

[Explanation of symbols]

 1 base 2 take-up reel 4 take-up shaft 4a latch plate 5 take-up spring device 11 pole 13 latch cup 13a pivot shaft 17 ratchet wheel 18 main gear 20 tapping screw 21 idle gear 22 control plate 23 lever 23a engaging protrusion 23b cylinder Shaped portion 23c Cam arm portion 23d Inner cam surface 24 Lock arm 24a Engagement portion 24b Engagement protrusion 31 Locking means 32 Vehicle body acceleration sensing means 38 Torsion coil spring 40 Cam groove 41 Cam surface 42 Cam surface

Claims (1)

[Scope of utility model registration request] 1. A rotation lock means that engages with a winding shaft of a retractor for winding a webbing to lock the rotation of the winding shaft in a webbing pull-out direction, and activates the rotation locking means in an emergency of a vehicle. A retractor for a seat belt having an emergency lock mechanism having inertial sensing means, wherein the inertial sensing means is activated in accordance with a webbing winding state to engage the rotation lock means with a winding shaft. Alternatively, the control means driven according to the non-engagement position engages with the swinging end of the transmitting means and the swinging end portion of the transmitting means, which is swingable between a position for activating the inertial sensing means and a position for not activating the inertial sensing means. The webbing has a first guide part and a second guide part for rocking the transmission means, and a control panel which is rotated in response to the rotation of the winding shaft. take Up to the rotation, the swinging end of the transmission means is engaged with the first guide portion of the control panel to a position where the transmission means does not activate the inertia sensing means, and the webbing is pulled out by a predetermined amount. Rotation, the swing end of the transmission means is moved to the second side of the control panel.
A retractor for a seat belt, which can be moved to a guide part of the seat belt so that the transmission means can activate the inertia sensing means.