JPS6147733B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an emergency locking safety belt retractor mechanism used to adjustably anchor a safety belt and/or to restrain a passenger to a seat of a vehicle during an emergency operation. The present invention relates to a harness assembly. The present invention is particularly directed to a belt webbing tension relieving device for limiting the tension applied to a belt by a storage reel bias spring.
Regarding. Such tensile forces, if not reduced or relieved, can cause discomfort to passengers when using safety belt devices, and are well known in the art in the case of certain automatic lock retractors. This tightens the passenger's body so tightly that the passenger is reluctant to use the safety belt system.

It has been recognized in the past that there is a need for an improved tension relief mechanism that can reduce the tension applied to a safety belt by a belt storage reel bias spring. Furthermore, such a pull-relief mechanism can operate automatically in such a manner that when a passenger tightens his or her belt, the belt simply stretches, allowing the passenger to move freely without tightening his or her body; It has been recognized that the best option is one that can be reset automatically when the device assumes its normal position of use. In addition to desirable low tensile force characteristics, it is desirable to have a device that allows the belt to have limited low tensile force movement in order to allow a small amount of movement for the passenger after the belt has been tightened.

SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to provide a tension reduction device for a safety belt retractor, in which the tension reduction function can be reliably obtained by simply extending the safety belt from its storage reel. It is to provide.

Another object of the invention is to provide low tension travel that is confined to the belt in low tension conditions.
It is an object of the present invention to provide a device which allows a passenger to perform a slight movement while the retractor is in a low tension state.

Another object of the present invention is to provide a device that can automatically set and disable the strain relief device in response to normal handling operations of the safety belt.

Generally speaking, the present invention provides a latching device for a safety belt retractor having a belt storage reel and associated belt biased toward a belt storage position;
a latching device adapted to prevent said storage reel from moving toward a storage position when the belt is simply stretched, and to relieve tension forces in the belt due to biasing forces of the storage reel; and a device for providing limited, low tension movement of the belt when movement of the belt is prevented by the latching device. Furthermore, a device is provided for deactivating the latching device. When an extension or retraction movement of the belt is performed, the storage reel can be moved beyond the limited low tension movement limit for the belt towards a belt storage position.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

The emergency lock safety belt retractor mechanism shown in FIG. 1 has been improved in accordance with the present invention and is designated generally by 2. This typical retractor mechanism has a safety belt 1, which is wound around a safety belt storage reel 3 fixed to a reel shaft 3a. The retractor frame 7 is conventional and has a U-shape, and is provided with side braces 6 to increase rigidity.

The drawer mechanism shown in FIG. 1 can be mounted in a conventional manner on a vehicle such as an automobile, for example by bolting the drawer frame 7 to the vehicle frame. The retractor mechanism, indicated generally by 2, normally rests on the passenger seat in a position such that the vehicle inertial sensing device 8 is operatively mounted and the safety belt 1 can be extended around the passenger of the vehicle. Installed adjacent to the vehicle. As is common in this type of retractor mechanism, the storage reel 3 is biased toward the belt storage condition by a clock-shaped spring associated with the reel within the spring housing 15.

As shown in FIG. 1, a pair of ratchet wheels 4, 4' are provided in conjunction with the storage reel 3 to facilitate locking of the reel to prevent the belt from elongating in the event of an emergency situation. ing. As conventionally, each ratchet wheel 4, 4' has a plurality of teeth and is adapted to engage a locking bar 5 actuated by a vehicle inertia sensing device 8 in the event of an emergency situation. It's summery.
For details of the operation of this retractor, please refer to the U.S. Patent No.
Reference should be made to No. 3889898 (2iv).

A belt tension relief device is provided to prevent the storage reel 3 from rotating towards the belt storage condition when the belt 1 is extended, so as to relieve the tension in the belt 1 due to the biasing force of the storage reel 3. It's summery. As shown in FIG. 3, the ratchet wheel 40 is fixed to the outer end of the reel shaft 3a by a set screw 42. As shown in FIG. The ratchet wheel 40 has a plurality of teeth 41 which, when engaged with the associated pawl 20, rotate in the same direction as the hour hand of the ratchet wheel 40, as shown in FIG. It is intended to prevent The ratchet wheel 40 and associated pawl 20 form a latching device that prevents the storage reel from moving towards the belt storage condition when the belt undergoes simple extension;
This reduces belt tension caused by the biasing force of the reel spring.

As shown in FIGS. 1 to 3, the pawl 20 of the latching device is pivotally attached to the side wall 14 of the retractor frame 7 by a pivot pin 21. As shown in FIGS. The pawl 20 has a locking surface 23, and as will be described later, the pawl is attached to the pawl wheel 4 by gravity.
When it falls into zero, it engages with any one of the teeth 41 of the ratchet wheel. Such movement of the pawl 20 is restricted by a limit pin 24 which engages a slot 25 formed in the side wall 14 of the retractor as shown in FIGS. 2 and 3. . As will be described in detail next, the engagement and disengagement of the pawl 20 and the ratchet wheel 40 are performed by a disengagement device acting on the limiting pin 24 and a disc driven by friction acting on the cam follower pin 22. controlled.

As is clear from the above description, the retractor of this embodiment automatically locks the extension of the belt when the sensing device 8 senses an abnormal inertial state of the vehicle. However, when such abnormal inertia conditions do not occur, the belt can be extended at the driver's will. Furthermore, as is clear from the above explanation, when the driver extends the belt, the latching device consisting of the ratchet wheel 40 and pawl 20 automatically prevents the belt from being retracted, and is not affected by the action of the internal device. It imparts tension-reducing properties to the belt, allowing the belt to have limited, low-tension movement as described below.

The device for effecting limited low-tension movement in this embodiment consists of a tensioning arm 10 equipped with a release device 11, which does not act on the tension-reducing device when the arm is moved to the position shown in FIG. It's becoming like that. As is clear from FIG. 2, the release device 11 of the tension arm 10 moves the cam follower pin 22 of the pawl 20 into the unlocked state by cam action.

The tension arm 10 and the release device 11 are connected to the retractor frame 7.
is movably mounted on the storage reel 3 and is adapted to sense the tension in the portion of the belt being withdrawn from the storage reel 3 as the belt 1 is extended and retracted relative to the storage condition. As shown in FIGS. 4 to 6, the tension arm 10 is pivotally connected to the retractor frame 7 at its inner end, and is biased toward the belt by a spring 12 in a direction opposite to the hour hand; The guide roller 13 then engages with the belt and is adapted to cause a secondary storage of the belt by the tension of the tension arm elastic spring. A guide roller 13 is provided at the outer end of the tensioning arm 10 and is adapted to engage the belt 1 when it is moving under low tension. By engaging the guide rollers 13, the belt 1 is biased transversely to the length of the portion of the belt extending out from the storage reel 3, whereby the belt is biased in two directions. It is then stored.

When the safety belt is fully retracted as shown in FIG. and retains the pawl, so that when the belt is extended as shown in FIG.
moves in the same direction as the hour hand due to the tension of the belt, and when the reel is wound in the opposite direction to the hour hand due to continuous stretching of the belt 1, the teeth 4 of the ratchet wheel move in the same direction as the hour hand.
The pawl 20 engaged with 1 is released. The locking device is therefore normally provided to lock the tension relief device in the operative position when the belt undergoes a simple extension. Once the claw 20 engages the ratchet wheel 40 and locks the reel 3 so that it cannot be retracted,
Next, even if this belt becomes slack, the guide roller 1
It is initially absorbed by the lateral biasing effect of the tension arm on the belt via 3 (within the limits of lateral movement of this roller). If the belt 1 subsequently slackens and the tensioning arm 10 moves under its spring bias to the position shown in FIG. Make sure you can incorporate it. Since the spring of the reel is stronger than the biasing spring for the tension arm 10, retraction of the belt due to the unwinding action of the storage reel will cause the tension arm 10 to be placed in the counterclockwise position of FIG. When the belt is in tension, move it to the position (Fig. 5). Frictionally driven friction disc 3 to facilitate complete retraction of the belt by the action of the reel unwinding spring
0 is provided, and when the rewinding operation is performed as described later, the tensile force reducing device is set to the inoperative position, that is, claw 2.
0 is maintained at a position away from the ratchet wheel 40.

Disabling the latching mechanism of the tension relief device when a retraction movement of the belt is performed, allowing the storage reel to rotate towards the belt storage condition, i.e. the belt is subject to said limited low tension movement relative to said belt. A device is provided which allows extension movements to be carried out beyond the limits. The device includes a friction disk 30 as shown in FIGS. 1-6.
This friction disk 30 is rotatably mounted on the reel shaft 3a, and biased against the inner surface of the ratchet wheel 40 by a spring washer 33. Therefore, if the reel shaft 3a rotates in either direction, the ratchet wheel 40
The frictional engagement of the friction disc 30 causes it to be driven within permissible limits in the direction of rotation of the storage reel by means of the limit pin 32 associated therewith. As shown in FIGS. 2 and 3, the limiting pin 32 fits into a limiting slot 9 in the retractor side wall 14 to limit arcuate rotation of the disc 30.

Said friction disk 30 has a contact or cam surface 31 which engages the follower pin 22 on the pawl 20, disabling the tension relief device and fully retracting under the action of the reel spring when the belt is released. It is becoming more and more popular. As is clear from FIG. 2 and the partial description of this figure, the belt becomes slack;
When the tension arm 10 engages the associated release device 11 with the limit pin 24, the pawl 20 leaves the ratchet wheel 40. At this point, the storage reel 3 starts an unwinding movement under the action of its spring, whereby the ratchet wheel 40 rotates clockwise and the friction disc 30 is therefore frictionally driven clockwise. , positioning the contact surface 31 under the driven pin 22 of the pawl 20. Therefore, if the strong reel spring pulls the belt inward, thereby moving the tension arm 10 clockwise and thus the release device 11 away from the limit pin 24, the pawl 20 will move against the disc contact surface. 31
is maintained in the unlocked state.

Next, let us consider the case where the belt begins to extend, assuming that the retractor and its constituent members are in the state shown in FIG. The initial extension moves the pulling arm 10 clockwise toward the position shown in FIG. 4 before the reel rotates. The pawl 20 separates the tension arm 10 from the release device 11 but remains unlocked. This is because the friction disc contact surface 31 engages the cam follower pin 22. However, as shown in FIG. 5, if the belt 1 continues to stretch, the storage reel 3 will rotate, and the counterclockwise rotation of the associated ratchet wheel 40 will cause the friction disc 30 to move against the limit pin in the limit slot 9. 32 is frictionally driven in a counterclockwise direction within the travel limits of 32, allowing the pawl 20 to latch the ratchet wheel 40. Once the extension of the belt 1 has ceased, the tension release device is activated automatically and the slack of the belt is reduced by the lateral biasing force of the tension arm 10 within its limits of movement between the positions of FIGS. 5 and 6. It is absorbed in In FIG. 6, the slackness of the belt 1 causes the tensioning arm 10 to move sufficiently counterclockwise due to its biasing force, causing the associated release device 11 to engage with the limiting pin 24 and thus the tensioning force It is designed to release the mitigation device. Next, unwinding of the storage reel 3 takes place, first moving the friction disc 30 to the position shown in FIG.
Therefore, during the subsequent winding operation, the pawl is held unlocked, and as long as the belt is taut, the strong reel spring causes the tension arm 10 to move clockwise, and the mechanism As shown in the figure,
The released belt now occupies the fully unwound position.

In the second embodiment shown in FIGS. 7 to 9, the friction disk 130 has two contact surfaces 131, 13.
2, and a recess 133 is located between these contact surfaces. In this embodiment as well, when the belt 1 is released and retraction occurs in the same way as in the previous embodiment, the friction disk 130 causes the limiting pin 32 to move into the limiting slot 9.
Rotate clockwise until the left limit is reached. This rotation brings the surface 131 into contact with the cam follower pin 22, and the lock pawl 20 is moved by the cam action to the ratchet wheel 40.
, and is therefore free to perform a backward rotation regardless of the position of the tensioning arm 10 (FIG. 7).

In the embodiment of FIGS. 7 to 9, the belt 1
expands, the friction disk 130 rotates counterclockwise until the limit pin 32 reaches the opposite limit of the slot 9, and the disk surface or cam surface 132 is moved by the cam action to the driven pin 22 and the pawl 20. is removed from the ratchet wheel 40, thereby preventing noise from the ratchet wheel when the belt 1 is extended (No. 8).
figure).

After tightening the belt, a slight retraction movement of the belt takes place and the friction disc 130 rotates clockwise to a neutral position, in which the pawl 20
engages the released ratchet wheel 40 and assumes a non-tension feature.

A third embodiment of a safety belt tension relief device and apparatus for low tension belt movement according to the present invention is shown in FIGS. 10-13. The drawer, designated as a whole by 202, has side walls 202, as in the drawer shown in FIGS. 1-3.
It has a frame 207 with 14. The safety belt 201 is wound onto a storage reel 203, which further has a shaft portion 203a supported by a suitable bearing in the side wall 214. Although not shown in the figure, opposite shaft members and bearings are provided on opposing side walls of the retractor frame 207, on which the retractor reel is mounted, and in the normal state, the retractor spring 215
This action biases the reel into the belt winding state. As shown in FIG. 11, retractor spring 215 is keyed to reel shaft 203a to bias the shaft into a fully retracted state. The rewind spring 215 is housed within a housing 215a which also includes a tension relief device and a device for providing low tension travel to the belt, as described below with respect to FIG. As in the previous embodiment,
The reel also includes a ratchet wheel 240 that engages the locking pawl to prevent belt extension in an emergency situation.

In this embodiment, the device for releasing the tension on the belt as it stretches includes a ratchet wheel 240 with a plurality of teeth 241, which teeth are connected to the pawl 22.
0, in particular, as shown in FIG. 10, it is adapted to engage with the claw surface 223. As shown in FIG. 11, the claw 220 has its inner end attached to the side wall 22 of the housing.
The claw 2 is pivotally attached to the pin 221 attached to the
20 is limited by the internal action of cam follower pin 222 and sidewall slot 225. The outer free end 224 projects outwardly and is adapted to engage a release device associated with a tension arm device according to the invention described below. Pawl 220 is biased into engagement with the ratchet wheel by a coil spring 216 connected at its opposite ends to pins 217 and 218, respectively. Therefore, the pawl 220 is normally biased toward the locking position of the ratchet wheel 240 to prevent unwinding of the storage reel 203 and is subjected to the action of the friction disk 230 and the tension arm 210. .

As shown in FIGS. 10 and 11, the friction disc 230 is rotatably mounted to the inner hub portion of a ratchet wheel 240, which is pivoted by a keyway and retaining ring arrangement as shown. It is fixed on 203a. As in the second embodiment described above, the friction disc 230 has a first contact surface 231 and a second contact surface or cam surface 232. Furthermore, a limiting member 233 is provided so that the arcuate rotational movement of the friction disk 230, which is effected by the action of a ratchet wheel 240, is caused by the rotation of the pawl pivot pin 2 as shown in FIG.
21 to the movement provided by the gap between the surface 232 and the limiting member 233. The friction drive of the friction disk 230 by the ratchet wheel 240 is the 11th
This is done by an interface between the reduced surface 235 of friction disk 230 and the underside of contacting ratchet wheel 240, which is acted upon by a disc spring washer 236 as shown. The primary role of the friction disc 230, similar to that of the friction disc 130 previously described, is to control the movement of the locking device pawl 220 during belt extension and retraction.

In the preferred embodiment, the device for providing limited, low-tension movement to the belt when the tension relief device (including the latching device consisting of pawl 220 and ratchet wheel 240) is actuated is It has a tension arm 210 pivotally attached to a bushing 210a as shown in FIGS. 10 and 11. This tensioning arm 210 has a release device 211, which is connected to the first
As shown in FIGS. 0 and 11, it consists of a laterally extending pin which engages and holds an extension 224 of a pawl 220 when the tension arm is moved under the action of an associated biasing spring 212. It's starting to come off. As shown in FIG.
is anchored at one end 212a to the drawer frame and at the other end to the bush 210a of the tension arm 210. The moment arm of the force of the spring 212 acting on the tension arm 210 (the distance between the longitudinal axis of the reel shaft 203a and the spring 212) is reduced by the bending of the spring 212 around the hub 210b. Therefore, as the force of the spring increases as it stretches, the moment arm decreases in approximately direct proportion, imparting a substantially constant belt tension through the tension arm 210.

As shown in FIGS. 10 and 11, a guide device 213 is mounted on the free end of the tension arm 210,
It is adapted to engage with the belt 1. The guide device 213 is pivotally mounted on the outer end of the tension arm 210 and is adapted to roll as it engages and guides the belt within the surrounding housing 150, as shown in FIGS. 12 and 13. It's getting old.

When actuated, the tension arm 210 releases its associated spring 21 before the first stretch of the belt takes place.
2 to a position as shown in FIG. 13, in which the associated pawl 220
is held unlocked. As the belt extends, the initial movement of the belt only tensions the belt and moves tension arm 210 from a position as shown in FIG. 13 to a position as shown in FIG. Further extension of the belt causes storage reel 203 and therefore ratchet wheel 240 to rotate clockwise. When the ratchet wheel 240 rotates clockwise in this manner, the friction disk 230 is frictionally driven clockwise as shown in FIG. 10, and the cam surface 232 comes into engagement with the limiting pin 221. Contact surface 23
1 below the driven pin 222 of the pawl 220.
Therefore, when the belt is extended, the pawl 220 remains unlatched.

When the user extends the belt to the desired use position and tightens it to the desired position, the belt is retracted slightly under the biasing force of the reel spring 215, causing the reel and ratchet wheel 240 to Tsute disc 2
30 to the surfaces 231 and 23 below the pin 222
2, so that the pawl 220 is biased by the spring 216 and the pawl wheel 240
into engagement with the storage reel 203, preventing further unwinding of the storage reel 203. The belt tension relief device is therefore positioned in an activated state. If a slight retraction movement occurs, the friction disk 230
moves to activate the tension relief device, which may cause the safety belt to loosen further during use. However, if such additional slack occurs, tension arm 210, under the biasing force of associated spring 212, pulls the belt within housing 150 laterally toward the dotted line position in FIG. To perform low tension movement of a belt without releasing a relief device. As previously mentioned, in the preferred embodiment, a spring 212 with a tension arm 210 as shown.
causes the belt to perform a low tensile movement within the low tensile force movement range.

When the tension relief device and the low tension movement generating device are in operation as shown in FIG. 12, the belt moves through the arcuate range of motion of the tension arm 210 between the positions shown in FIGS. Extending or retracting movements can be performed beyond the limits of movement allowed by. In the event of elongation, the pull relief device is disabled as shown in FIG. It will be reset. When the user puts the belt on the 12th
In the event of excessive loosening beyond the position shown, tension arm 210 moves to the position shown in FIG. 13, disengaging pawl 220 from ratchet wheel 240. As soon as the pawl 220 releases the ratchet wheel 240, unwinding of the belt occurs and thus the friction disc 230
is rotated clockwise until the limiting member 233 hits the stop pin 221 as shown in FIG. In this position relative to the friction disc 230, the second contact surface 232 moves below the follower pin 222, keeping the pawl unlocked during subsequent unwinding of the storage reel and pulling the belt through the housing. Pull even harder and therefore the tension arm 21
0 from the claw 220.

Figures 14 and 15 illustrate a fourth embodiment of the present invention, which may be used with any safety belt retraction mechanism of the strap acceleration type, vehicle inertia sensing type, or other type. be able to. This otherwise conventional drawing machine is indicated generally by 310 and includes a generally U-shaped frame 311 which is connected to the base 3.
12 and a pair of opposing side walls, side wall 31
3 is shown in FIGS. 14 and 15. The retractor frame 311 is mounted on the vehicle frame in a normal manner,
The associated safety belt is placed in position to be withdrawn from the retractor and placed in the position of use around the driver by means of an associated conventional tightening device.

As shown in FIG. 15, the safety belt 315 is wound onto a reel 316 having a conventional pair of end lock pawls, ratchet 317 being shown in FIG. The storage reel 316 has a reel shaft at each end thereof and is adapted to be mounted on the side wall of the retractor by means of a suitable bushing, the shaft 318 being fitted into the wall 313 as shown in FIG. It is mounted in a related bush. A conventional retractor locking device (not shown) may be provided to lock against a ratchet, such as wheel 317, to prevent extension of the belt in an emergency situation.

The retractor is provided with a conventional biasing device which normally biases the belt storage reel 316 toward the retracted or belt winding condition. In this embodiment, the biasing device as described above includes a conventional retraction spring 320, which is secured at one end to a conventional housing 321 mounted on wall 313. The retraction spring 32
The free or working end 322 of 0 fits within a slot 323 provided in shaft 318 to bias the belt storage device, which normally comprises storage reel 316, toward the belt storage condition as shown in FIG. I'm starting to let them do it. Shaft 318 has a ring groove 324 adapted to receive a retaining ring 333 as described below. The device for limiting the retraction movement of the belt storage device and reducing the tension force on the belt (due to the biasing device of the spring 320) has a force transmission device generally designated by 330 and a ratchet wheel 331;
It includes a pawl 335 selectively engageable with the ratchet wheel 331 and a tension arm arrangement designated generally at 340, which arm is in transverse contact with a portion of belt 315 extending through an end contact roller 343. It is becoming more and more engaged. As will be discussed in more detail below, when this tension relief device is actuated, the force of the biasing device (spring 320) is applied through ratchet wheel 331, pawl 335, and tension arm 340 to create a lateral force on the elongated portion of belt 315. , so that the mechanical leverage has an overall reduced effect on the belt.

As shown in FIG. 14, the force transmitting device, designated generally by 330, comprises a ratchet wheel 331 having a plurality of teeth 332, which teeth are keyed on the ratchet wheel when stretching of the belt takes place. It faces in a direction opposite to the direction of rotation of the shaft 318. Shaft ring groove 324
The spring washer 333 (Fig. 15) that fits into the ratchet wheel 3
31 is prevented from moving axially from shaft 318 to which it is keyed by key member 334 (FIG. 14). Therefore, the ratchet wheel 33
1 rotates with storage reel 316 in response to movement of belt 315 in an extended or retracted state.

Pawl 335 engages each tooth of ratchet wheel 331 to receive the force of the biasing device acting through ratchet wheel 331 and transmit it to the tension arm device, generally designated by 340. As shown in FIG. 14, the pawl 335 has a first end forming teeth 336 thereof, and the pawl 335
is adapted to engage any tooth 332 of.
A cam pin 337 is provided on the claw 335,
It engages a frictionally driven friction disc 350 to selectively engage the pawl and ratchet wheel 331 during belt extension and retraction movements as will be described below. The pawl 335 still has oppositely extending arms or tails 338, the ends of which are connected to the abutment portions or pads 33.
9 is formed. The function of this pad will be described later. Importantly, a pawl 335 according to the present invention is movably mounted on the tensioning arm device such that the pawl transmits the force received from the biasing device to the tensioning arm device designated generally by 340. That is what we are doing. In the embodiment shown in FIG.
35 is pivotally mounted approximately at its central portion on a mounting pin or support pivot pin 345;
This pivot pin is fixed to the tension arm device described below.

As shown in FIGS. 14 and 15, a pull arm assembly, generally designated 340, is pivotally mounted to the upright portion 313' of the retractor side wall 313 by a pivot pin 342. Said arm 3
On 41 there is provided a device for lateral contact with belt 315, which in the illustrated embodiment consists of a roller 343 pivotally mounted on arm 341. The pulling arm device, designated generally by 340, still has a pair of pivoting arms in the form of a U-shaped member, the arms being pivotally mounted on opposite sides of the retractor frame and between the arms. is straddled by Laura. According to the invention, the arm 341 includes another extension or suspension portion 344, which portion is connected to the aforementioned support pin 345.
is carried. The arm 341 is mounted on the inner wall of the retractor side wall 313, and the claw device 335 is mounted on the outside thereof. An arcuate slot 346 is provided in the side wall 313 to allow the support pin 345 to be inserted into the claw 33 as described below.
5 and a belt 315 on the tension arm device to allow free movement relative to the wall 313.

As shown in FIGS. 14 and 15, the friction disk 350 is rotatably mounted on the shaft 318.
The reduced surface section 351 faces towards the inner surface of the ratchet wheel 331. Friction disc 350 is normally biased into friction-driven engagement with wheel 331 by an associated spring washer 352 fitted between the disc arrangement and the outer surface of retractor wall 313. It is being Friction disk 350 further includes a pawl actuating portion 353 which actuates pawl pin 337 to release the pawl from ratchet wheel 331 during extension as shown in FIG. 16, while allowing the pawl to engage ratchet wheel 331 when a slight retraction movement as shown in FIG. 16 is performed. The pawl operating portion 353 of the friction disk 350 is 1
It has a pair of end stop surfaces 354, 355 which cooperate with pin 337 to prevent friction disc 350 from rotating when storage reel 316 is rotated in response to belt motion.
It is designed to restrict the rotational movement of the Additionally, a pair of spaced apart pin contact surfaces or raised portions 356, 357 are provided on opposite sides of the central groove or notch 358. 1st
As shown in FIG. 4, when the belt 315 performs an elongation movement, the belt storage device including the storage reel 316 rotates counterclockwise, which causes the associated friction disc 350 to rotate counterclockwise, causing the raised portion 357 to rotate in the counterclockwise direction. is moved below pin 337 so that the pin abuts stop surface 355 and prevents further rotation of friction disc 350. However, as shown in FIG. 16, if belt 315 retracts slightly, storage reel 316 and associated ratchet wheel 3
31 rotates clockwise, the friction disk rotates slightly clockwise, and the pawl pin 3 acts as a driven member.
37 is formed into a notch or groove 358 by cam action.
inward, thus engaging pawl tooth 336 with one of the teeth of the ratchet wheel. The engagement between the pawl 335 and the ratchet wheel 331 can be effected by gravity, as far as the orientation of the retractor within the vehicle allows, or by biasing the pawl by a pawl spring 360, as is clear from the illustrated embodiment. 331. The illustrated pawl spring 360 is attached to the mounting pin 36 on the pawl.
1 and an associated mounting pin 362 mounted on the retractor side wall 313. As is clear from the above description, when the belt 315 is slightly retracted (FIG. 16), the tensile force limiting device according to the present invention is activated.

As shown in FIG. 16, when the tension reducing device of the present invention is activated by a small retracting movement of the belt 315, the biasing force of the retractor spring 320 is applied to the ratchet wheel 33.
1, provides a low tensile force retraction effect on the belt 315 through the pawl 335 and the tension arm device generally represented by 340. The claw 335 is the tension arm 34
1, the biasing force of the retractor spring 320 transmitted through the ratchet wheel 331 and the pawl 335 is transmitted to the retractor pivot pin 342 and the pawl pivot pin 34.
5 through a relatively short lever arm between the axes of the belt 315 and the contact point of the roller 343 on the belt 315;
The tension arm is rotated counterclockwise across the belt through a relatively long lever arm between the pivot axis at pin 342. The lateral reaction force on the belt 315 is therefore reduced in proportion to the ratio of the corresponding lever arm, and as long as the pawl 335 is engaged with the ratchet wheel 331, the single spring biasing device 320 forces the belt 315 A low tensile effect occurs on top.

As shown in FIG. 17, when the tension reducing device of the present invention is operating in a low tension state, the belt 31
5 has limited movement between the retracted positions of FIGS. 16 and 18. When this low tensile force movement is performed, the ratchet wheel 331, friction disk 350, and pawl 335 rotate together as a tension arm 341, from the initial position shown in FIG. 16 to the position shown in FIG. Move clockwise to the retraction limit position for low tensile force movement. The retractor state shown in FIG. 17 represents a typical intermediate position for the strain relief device when the belt 315 performs low strain movement in a retraction or extension manner. However, if the arm 341 is moved sufficiently in a low tension manner until the belt reaches the position shown in FIG.
9 is in contact with the inner surface 314 of the retractor base 312, and when the belt 315 is loosened, the pawl 335 pivots around the impact pad 339 as shown in FIG. is released from the ratchet wheel 331. The state of the tension relief device shown in FIG. 19 occurs instantaneously. The reason is that the force of the biasing device acting on the storage reel immediately causes the belt 315 to begin retracting, and due to the tension of the belt, the tensioning arm 341 is free to move to the inoperative position shown in FIG. It is from. When belt 315 performs a retraction motion, clockwise rotation of ratchet wheel 331 causes friction disc 350 to rotate clockwise, positioning the associated raised portion 356 below pawl pin 336. Rotation of friction disk 350 in the clockwise direction is limited by the engagement between stop surface 354 and pin 336. Next, as shown in FIG.
is maintained in a state where it is removed from the pawl wheel 331, and the pawl 33
5 to the pin 345 and the arm 341 does not rotate relative to the belt 315. Arm 341 thus exerts no tension or frictional traction force on belt 315 and it freely retracts into the retractor frame on storage reel 316.
The strain relief device remains in this inoperative position until the next extension of the belt 315 as shown in FIG. 14, and then the sequence of actuation shown between FIGS. It happens in

[Brief explanation of the drawing]

FIG. 1 is an elevational view of a safety belt retractor including a first embodiment of a strain relief device according to the present invention and a device for providing limited low strain movement of the belt in use. Figure 2 shows the arrow in Figure 1 -
FIG. 3 is a side view of the safety belt retractor as seen in the direction of FIG. FIG. 3 is a cross-sectional view taken along line - of FIG. 2; FIG. 4 is a partial side view of the safety belt retractor of FIG. 1, showing the tension relief device in a disengaged state. 5 is a partial side view of the safety belt retractor shown in FIG. 1; FIG. FIG. 6 is a partial side view of the safety belt retractor of FIG. 1 showing the tension relief device fully released. Figure 7 is the first
2 is a partial side view of the safety belt retractor shown in the figure, showing a second embodiment of the tension relief device; FIG. FIG. 8 is a partial side view of the safety belt retractor of FIG. 7 showing the tension relief device fully released; 9 is a partial side view of the safety belt retractor of FIG. 7 showing the tension relief device fully engaged; FIG. FIG. 10 is a side view of a safety belt retractor similar to that shown in FIG.
A third embodiment of the tensile force reduction device is shown. FIG. 11 is a cross-sectional view of the retractor and strain relief device of FIG. 10 taken along line XI--XI. 1st
2 is a sectional view taken along line XII--XII of FIG. 11; FIG. 13 is a view similar to FIG. 12 but showing the strain relief device disabled. FIG. 14 is a side view of a fourth embodiment of the tensile force reduction device.
FIG. 15 is a detailed cross-sectional view of the tension relief device of FIG. 14 taken along line -. 16 is a side view of the strain relief device of FIG. 14, with the belt retracted slightly following the extension movement shown in FIG. 14; FIG. 17th
14 is a side view of the strain relief device of FIG. 14 when the strain relief device is in an activated state and the safety belt is in a low tension condition in accordance with the present invention; FIG.
FIG. 18 is a side view of the tension relief device of FIG. 14, showing the belt having moved to the retraction limit of its travel in its low tension state. FIG. 19 is a side view of the tension relief device of FIG. 14, showing the tension relief device disabled. Figure 20 is the 14th
Figure 3 is a side view of the tension relief device shown when the belt is retracted under the biasing force of an associated reel biasing device; In the figure, 1 is a safety belt, 2 is a safety belt retractor, 3 is a storage reel, 3a is a reel shaft, 4,
4' is a ratchet wheel, 5 is a locking rod, 6 is a horizontal support, 7 is a retractor frame, 8 is a vehicle inertia sensing device, 9 is a restriction slot, 1
0 is a tension arm, 11 is a release device, 12 is a spring, 1
3 is a guide roller, 14 is a side wall, 15 is a housing, 20 is a pawl, 21 is a pivot pin, 22 is a cam follower pin, 23 is a retaining surface, 24 is a limit pin, 25
30 is a slot, 30 is a friction disk, 31 is a contact surface, 32 is a limit pin, 33 is a spring washer, 40 is a ratchet wheel, 41 is a tooth, and 42 is a set screw.

Claims (1)

[Scope of Claims] 1. When the related safety belt is extended, the related belt storage reel 3, 203, 310 provided on the reel shaft 3a, 203a, 318 is normally placed in a state in which the safety belt is retracted. a first spring device 1 that applies a first belt tension force by biasing the
In the tensile force reducing device for a safety belt retractor having No. 5, 215, 320, a ratchet wheel 40, 240, 331 provided on the reel shaft 3a, 203a, 318, and a ratchet wheel 40, 240, 331 provided on the reel shaft 3a, 203a, 318; a pawl 20, 220, 335 pivotally mounted on the frame of the retractor so as to engage the reel and prevent the retracting movement of the safety belt;
and rotatably mounted on the reel shaft and frictionally driven in response to rotation of the reel to automatically engage the pawl when the safety belt is first extended and then slightly retracted. a friction disk 30, 130, 230, 350 that is inserted into the ratchet wheel and engages with the ratchet wheel to prevent its rotation; and a second belt tensile force that is smaller than the first belt tensile force. a second spring device 12, 216, 335, 34 applying a belt tension force to said safety belt;
5,342,341, and moving the pawl out of engagement with the ratchet wheel when the safety belt is further retracted by an amount greater than the slight retraction amount; Remover device 11, 211, 3
A tensile force reduction device for a safety belt retractor having 39. 2. In the tensile force reducing device for a safety belt retractor as set forth in claim 1, the pawl and the ratchet wheel are set in an unrestricted state when the belt is extended by an amount larger than a predetermined amount. Cam devices 31, 132, 232, 35 that automatically operate
5. A tensile force reduction device for a safety belt retractor having 5.