CA1080191A - Belt roller for motor vehicle safety belts - Google Patents

Abstract

INVENTION: BELT ROLLER FOR MOTOR VEHICLE SAFETY BELTS
INVENTOR: PER OLOF WEMAN
ABSTRACT OF THE DISCLOSURE
A belt winder for vehicle safety belts is provided with at least one locking member dynamically balanced on the axis of rotation of the winder's shaft and moved by an inertia member into locking engagement with teeth on the winder housing solely in re-sponse to sudden angular acceleration of the shaft. Means are provided for primary and secondary locking of the winder and for varying the time interval for response by the inertia member to shaft acceleration.

Description

~Q8~91 BELT ROLLER FOR MOTOR VEHICLE SAFETY BELTS
This invention relates to a belt roller for motor vehicle safety belts, with a rotatable shaft for winding of the extensible belt, and a lock against further pull of the belt, with a pivoted inertia body on the shaft, and a lock element, movable relative to the shaft, having an exterior curvature surface, and at least one lock stop.
Several belt rollers are known, by means of which the belt strap can be pulled out for reversal from the belt roll, while the vehicle in which they are built is moving. After the belt is put on, the roller exerts pull on the belt so that it fits close to the body. On the other hand it is necessary that the shaft of the roller is locked during an accident, so that the belt cannot be pulled out at this point.
Known locks work as a function of vehicle deceleration.
A contact element or sensor, as for example a pendulum, a ball or another inertia body, shift with strong deceleration of the vehicle and cause a lock of the shaft.
With other locking devices the roller shaft is locked -as a function of its revolving speed during pull-off of the belt, i.e. as a function of the pull-off acceleration of the belt or as a function of the centrifugal force.
Already known is a belt roller which has a special quick-lock, through which - with jerky pull-out of the belt - a locking body, responding definitely only to the angular acceleration, i.e.
the jerk of the belt strap, engages immediately after the accelera-tion with a cased retaining body.
In one type model, the inertia ring is formed with two pins diametrically set on the front side, and the locking body, set between the inertia body and the shaft, has a contact edge for the pins of the inertia body. The inertia body is a kind of fly-~. .~

1~80191 wheel, which has the same angular acceleration during slow pull-out of the belt strap from the roller as that of a shaft on which the end of the belt strap is fastened and the belt strap is wound on. Even the lock body - or the two lock bodies in a practical, different type model - are pivoted so on the pin, mentioned before, and the shaft, with regard to the centrifugal forces, that they do not make a turn around the said pin - during the pull-out of the belt strap - but rather remain fixed with regard to the shaft and the inertia body position, and assume also the mentioned angular acceleration. As long as a certain acceleration, whose value could be adjusted, is not exceeded, the angular acceleration could theoretically take ever higher values, without resulting locking. ~;
In an advantageous way this means that the belt roller does not respond to the centrifugal force so as to cause locking to result.
However, locking results immediately after angular acce-leration, i.e. a jerky pull-out of the belt, for example during an accident. The inertia body insures that, which does not follow the jerky increase of the angular acceleration of the shaft, so that a relative motion between inertia body and shaft occurs, and the locking bodies - pivoted on the shaft - are necessarily turned relative to the shaft. The front end of the locking bodies then engages with a lock ring which has teeth inside. The described belt roller is immediately locked.
Another suggestion has been improved in such a way that -regardless of the momentary local coordination of two teeth engag-ing with one another - locking is positively guaranteed without the risk of tooth tips breaking off or teeth jumping.
This is obtained by using only one locking body - cross-sliding to the belt roller shaft - which shows an interior cam sur-face opposite the curvature surface; the one cam surface oppositethe shaft is arranged in such a way that a sliding of the locking body is available before reaching the complete lock position, in the opposite direction to the rotating movement of the shaft; and a control body - rotating around the axis of the shaft, and radially fixed, - is engaging through a recess with the locking body. Breaking of the teeth or jumping from tooth to tooth with-out locking effect is prevented.
The basic idea of this older suggestion is that it is possible for the locking body to move against the rotating direc-tion of the shaft. Thus the tip of the locking body, that is, the lock stop located at the tip or the projection, has sufficient time to enter the base of the opposite tooth on the locking ring, and to get into contact with the opposite stop. Even only one tooth located on the locking body is sufficient to guarantee at -all times positive locking. It is especially preferred to arrange the projection with the lock stop on the back side - seen in rotat-ing direction of the locking body.
Both known type models can, however, be improved, espe-cially simplified, and designed for more versatile use with regard to potential applications. ThuS the invention is based on the task to improve the belt roller of the type described in the beginning, so that - with more economic production - the same or better safety can be guaranteed with reliable locking and a change of the locking time interval, or the time required for movement of the locking mechanism from an unlocked to a locked position upon collision of the vehicle.
In accordance with this invention, there is provided a belt roller for motor vehicle safety belts having a rotatable shaft to wind up and protract an extensible belt, locking means having an exterior surface including at least one lock stop and being mounted on the shafti a U-shaped mount having side walls;

a locking toothed wheel constituted by a toothed rim of an aperture in one of the side walls; a plastic bearing mounted on 108~191 the inside of one side wallto substantially close the aperture and support one side of the rotatable shaft; and acceleration of the shaft causing outward movement of the locking means relative to the shaft to move into locking engagement with the locking toothed wheel to lock the belt against further extension.
This invention also provides means for moving the locking body into a locking position in en~agement with a cased thrust body with inside teeth upon the exceeding of a certain angular acceleration of the shaft by a turn of the inertia body to the shaft, the inertia body being formed as a ring with at least one pin on the front side and contacts for a -3a-10~0191 spring, through which a spring, set on a cylinder element attached to the shaft, is coupled with the shaft, and the locking body being located between the inertia body and the shaft. It is here preferred that according to the invention the thrust body is formed as a toothed wheel, in the one side of the preferably U-shaped mount, in one piece with it. In the known type model men-tioned in the beginning, and also with the described older sugges-tion, the thrust body is designed as a locking ring, equipped with inside teeth, which is welded or screwed on the outside of the side wall of the mount. It is a considerable simplification and thus a more economic production possibility if, by eliminating this extra toothed ring, the toothed wheel is directly set in the already strong and stiff side wall of the base, so that the toothed wheel is formed in one piece with this side wall.
It is furthermore advantageous according to the inven-tion, when a bearing for the shaft is attached on the inside of the mount on the side wall with the toothed wheel. With the type models p-reviously discussed, an appropriately dimensioned opening in the side wall served as bearing for the attached toothed lock-ing ring. This opening is, according to the invention, increasedto the toothed wheel in the above-mentioned manner, so that the extra bearing is practically attached on the inside, which can be, for example in a very simple design form, a plate with an appro-priately dimensioned hole. The diameter of this hole is dimen-sioned so that it comprises the outer circumference of the belt roller shaft and holds it centrically.
This invention is directed to two type models, which correspond approximately with the examples mentioned in the begin-ning, but which will be described hereinafter in more detail. Two pivoting locking bodies are intended with the first type model, whereas with the second type model only one sliding locking body 108019~ ~
..
is used, which engages with the teeth of the toothed wheel in the side wall of the mount. The advantages obtained according to the invention apply in any case to both type models.
It is furthermore advantageous according to the inven-tion, to construct the bearing on the side wall of the mount of plastic material. This bearing - holding centrically the belt roller shaft and thus the inertia body - can bring the following advantage with the manufacturing from plastic: When, during an accident, very high pressure is applied to the belt strap and thus the belt roller, the bearing can twist and give way to one side, giving in on the strong pressure, and can deform, so that two reciprocally increasing locking effects result. The first locking effect is that in which the locking body with its teeth comes to engage on the outside with the inside toothed wheel in the side wall of the mount. The second locking effect is produced through a radial outside motion of the bearing and thus the respective end of the shaft, with a disk attached to this end of the shaft;
locking results toward the inside toothed wheel through the last mentioned force, that is the friction force between the disk and the toothed wheel.
In another embodiment of the invention, the spring set on the cylinder element with a preset spring stiffness can be replaced by another spring with a different spring stiffness.
This way the response time of the belt roller can be conveniently ;
changed by the manufacturer to better meet the requirements of the different countries. An increase of the spring stiffness prolongs - the time required for the inertia body, formed as a ring, to effect a movement of the locking body into direction of locking, during a sudden pull-out of the belt strap. Thus is increased the time which is necessary for the locking engagement between the locking body and the toothed wheel. It is therefore possible according to :, ., , , : .. - -10801~1 :
the invention, by changing the spring stiffness, to control the -locking sensitivity and to prevent in an advantageous manner a premature locking on the winding device.
It is especially advantageous according to the inven-tion, if the interchangeable springs have the same form. As we are concerned herewith a mass article with little space require-ments, the manufacturer needs to keep stocked only different boxes with springs of different spring stiffness for the different coun-tries according to the requirements in effect there. Other parts of the belt roller according to the invention need not be changed;
only springs with different spring stiffnesses need to be used to obtain the mentioned practical effect.
Further advantages, characteristics, and potential appli-cations of the invention discussed, can be seen from the following description in connection with the drawings. r Fig. 1 is a perspective view of the belt roller with locking toothed wheel;
; Fig. 2 is a perspective view of the winding shaft with disk attached to it;
Fig. 3 is a perspective view of the special coordination of the two locking bodies;
Fig. 4 illustrates the ring-shaped inertia body;
Fig. 5 shows the lamellar leaf spring;
Fig. 6 depicts, in side view, the inertia body with spring;
Fig. 7 is a top plan-view of the locking body;
Fig. 8 is a side-view of the shaft with attached disk;
Fig. 9 is a side-view of the assembled locking device on the belt roller in un-locked position;
Fig. 10 depicts the same arrangement as in Fig. 9, show-ing however an engaging of the pin on the inertia body with the 108~191 locking bodies;
Fig. 11 is a perspective view of a different type model of seat belt roller with locking toothed wheel;
Fig. 12 is a perspective view of the winding shaft with pitch circle disk attached;
Fig. 13 is a perspective view of the spatial coordination of the locking body;
Fig. 14 is a perspective view of the disk-shaped inertia body;
Fig. 15 is a perspective view of the initial stress spring with spring edge;
Fig. 16 is a perspective view of the locking wheel;
Fig. 17 depicts in perspective the ring holder; and Fig. 18 is a sectional view through the belt roller accordi!ng to the second type model of the invention, according to Figs. 11 to 17, with partly shown pitch circle disk, the locking body being shown in engagement with the teeth of the cased locking toothed wheel.
According to the first type model of the invention, a side wall with lock:ing toothed wheel with inside teeth 3 is pro-vided on the ~-shaped mount 1 of the belt roller. A bearing 2 is attached on the inside for the shaft 4.
Figures 1 to 5 illustrate an exploded perspective view of the locking device for the belt roller. The belt strap and the winding spring as well as other parts of the belt roller are not shown. It can be seen, however, that the winding shaft 4 - with the disk 5 attached to it on the front face - is put together in assembly in the direction of the dotted axis into the provided recesses. The disk 5 - on its front face surface - bears in the center the cylinder element 7 with the slit, and diametrically to it, two pins 6.

10~191 In Figures 3 and 7 the locking body is shown in that special type model, in which the boring 9c as rotating point is intended to be centric and in the thrust point, in which however a hole in the front half is made 9b for the intended disturbing of balance with regard to the rotating point. For matching to the diameter of disk 5 the locking body 9 is accordingly curved, and shows several locking teeth on its front end on the curved outside.
A contact edge 9d for the pin 12 of the inertia body 10 is also intended on the inside, but also on the front end of the locking body 9. It can be provided for three, four or more lock-ing bodies in the locking device, however, the arrangement with two locking bodies according to Figs. 1 to 10 is preferred for the first type model.
The locking body 9 is set on the pin 6 of a disk 5, so that it has the position shown in Fig. 9.
The lamellar leaf spring 8 is chosen according to desired sensitivity, that is, the response factor to the desired accelera-tion value, with regard to the spring stiffness, and is inserted in the desired pair of opposite slits 11 on the inside of the ring-shaped inertia body 10. On the front face - opposite disk 5 - the ring-shaped inertia body 10 has two diametrically arranged pins 12, with regard to its center. In assembling the locking device according to Figs. 1-5, the pins 12 catch through the distance between the two locking bodies 9, in the manner shown in Fig. 9, so that there is no contact between the locking bodies 9 and the pins 12.
It should furthermore be emphasized the desired advan-tage according to the invention, that the inertia body 10 is to be relatively solid. Together with the characteristics of the spring material and the arrangement of the spring which is inserted into the slit in the cylinder element 7, this relatively heavy inertia body 10 which also works as a fly wheel, can be well adjusted.
Compared to known devices the locking bodies can also be formed strong and solidly, which can take up almost half of the circular surface of the disk 5. It is understood that in turning of the locking bodies 9 around the pins 6 relative to shaft 5, their teeth can properly engage with the teeth 3 of the locking ring

2. It can be seen from Fig. 9 that the pins 12 do not necessarily rest against the locking bodies 9. Fig. 10 shows how the pins 12 engage with the locking bodies 9, when belt strap is abruptly pulled off from the winding shaft. This jerk in the belt strap, produces the acceleration which in this case should have exceeded the critical acceleration value, causing a relative turn between the shaft 4 and the inertia body 10. From this results the slope of the connecting line between the two pins 12 to the horizontal dash-dotted line shown in Figure 10, as contrasted with Fig. 9, where both the horizontal dash-dotted line and the connecting line between pins 12 are in alignment.
The bearing 2 shown in Figs. 9 and 10 is screwed to the inside of one side wall of the U-shaped mount 1. Within the toothed wheel 3 a broken line is shown which indicates the inside opening of this bearing into which shaft 4 can be inserted.
Due to the plastic material for the bearing 2, upon accident stress, the boring shown in Figs. 9 and 10 with the broken line circle can buckle, so that the outer surface of the disk 5 also comes to friction engagement with the sufficiently broad toothed wheel 3, and the second locking effect improves the effec-tiveness of the first locking effect between the teeth of the locking body 9 and the toothed wheel 3. The radially outward move-ment of disk 5 and shaft 4 ensures primary locking between locking body 9 and toothed wheel 3 and permits secondary locking between toothed wheel 3 and the outer surface of disk 5.

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Figs. 11 to 18 are exploded perspective views of the locking device for the belt roller, showing the second type model of the invention, in which only one latch 9 is used which is dynamically balanced on the axis of rotation of shaft 4 and slid-ably disposed over the disk for movement into and out of engage-ment with toothed wheel 3. Same parts are given again the same reference numbers.
Figures 11 to 18 are exploded perspective views of the locking device for the belt roller.
The pitch circle disk 5 bears on its front face surface in the center the cylinder element 7 with a slit, and in the bottom half a more than semicircular elongation in the form of a thick divided circle 13, whose upper side represents a cam surface 20.
The locking body 9 is shown in Fig. 13. To fit to the diameter of the pitch circle disk 5, that is, the interior circum-ference of teeth 3 of the cased locking toothed wheel, the locking body 9 is accordingly curved, i.e. it shows an exterior curvature surface 14. On its back end, the projection 9k is provided which holds the engaging tooth in the form of lock stop 9g. Rest stop 9h is arranged in front, seen in direction of turn.
The locking body 9 lies on the surface of the pitch circle disk 5 and cam surface 20 and can move freely in this plane without any pivot bearing at first.
Fig. 14 shows an inertia body 10 that is disk-shaped and functions as a fly wheel, and is provided with pin 15, which is intended for engagement with the recess 22 in the locking body 9. On the side of the inertia disk 10 opposite projection 15 is a small pin-shaped nose 16, in which a slit 17 is located about 120 diametrically displaced from nose 16 between two small eleva-tions.
Fig. 15 shows an embodiment of the invention having a .. .. . . - .

1080~9~

specially formed spring 8 with a protruding spring edge 8' and a loop 8" at the end of the spring which in assembly is to be put around the nose 16.
Fig. 16 shows perspectively the locking wheel 11, which is coupled to the inertia body 10 through spring 8 by stop or fric-tion clutch. Fig. 17 shows ring holder 12 having on opposite sides thereof adjusting cylinders 18 arranged with small inert bodies or sensors in form of balls 19 inside them.
The exact shape of the locking body 9 can be conveniently explained with reference to Fig. 13. The exterior curvature sur-face 14, which is interrupted in the center of gravity of the lock-ing body 9 by the recess 22, is opposite the cam successor surface 9f which is shown in a straight line. Seen in direction of turn, on locking body 9 in the back is the projection 9k on whose smaller front side is arranged lock stop 9g, and on whose larger back side locking surface 9 1 is attached. On the opposite, i.e. front side, on the locking body 9 is found a protruding nose 9i, whose front surface forms the lock stop 9h, and whose back surface forms the auxiliary lock stop 9m.
Fig. 15 shows the shape of the spring 8 well. The one end of the spring lies in the slit of the cylinder-shaped part 7 on the shaft 4, is then spirally wound around this cylinder part 7, until the other end laterally runs through the slit 17 on the mounted inertia body 10, to be bent twice at about 90 and attached to the nose 16 on the inertia body 10 by forming the spring edge 8' at the farmost other end with loop 8". The same advantageous effect is obtained in another type model with a uniformly curved or harmonically bent spring, instead of using the above-mentioned angles of 90 in the other type model.
The spring edge 8' is latched, that is, locked between the inside teeth 11' of the locking wheel 11, which has furthermore 108~)191 teeth 11" on the outside.
In assembled condition, the ring holder 12 is slid over the locking wheel 11, so that the sensors 19 are opposite the teeth 11".
The holder rotates around the axis shaft 4, or the pitch circle disk S. The holder is radially fixed, i.e. fixed in its length. Its radius is formed by the inertia body 10 with the pro-jection 15.
In assembled condition, the locking body 9 slides on the ring surface 21 within the cased locking toothed wheel. A thin plastic disk can be located on the wheel to reduce friction or to prevent the contact of metal on metal~
As previously mentioned, increasing the spring rate of spring 8 prolongs the time required for inertia body 10 to cease movement relative to disk 5 upon a sudden protraction of the belt strap, with the result that the time interval required to move locking body 9 into engagement with teeth 3 is increased. The spring rate or stiffness of spring 8 can thus be easily adjusted to control locking sensitivity and prevent premature locking of the belt winding device.
Upon an impact on the vehicle, e.g. by collision or cap-sizing of the vehicle, locking is produced through the sensors 19 in the ring holder 12. Locking is effected by the sensor 19 in the ring holder 12, which runs from the respective adjusting cylinder 18 toward the inside of the cylinder 18 and toward the exterior teeth 11" of the locking wheel 11. Thus the locking wheel 11, made preferably from plastic, is arrested and stops.
Due to the clutch engagement through spring edge 8' and the slit 17, the inertia body 10 immediately moves projection 15 and the recess 22, moving the locking body into the above-described lock-ing position. Now a force works from the stopped locking body 9 108019~
over inertia body 10 back to the locking wheel 11, whose outerteeth 11' could now break off due to the engagement with sensor 19, if it were not for the elastic back bending of spring edge 8', which works together with the retaining grooves lla, llb according to Fig. 5 (and in the other type model according to Fig. 16) on the interior surface of the locking wheel 11. As a resul.t, the ; spring edge 8' can jump from one groove or one tooth lla to the next groove or next tooth llb, with which is synchronized the lock-ing of the vehicle sensitive mechanism on the other hand. Accord-ingly the locking wheel 11 is further turned ratchet-like compared to the now stationary inertia disk 10.

Claims (2)

1. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.
   -- 1. In a belt roller for motor vehicle safety belts having a rotatable shaft to wind up and protract an extensible belt, locking means having an exterior surface including at least one lock stop and being mounted on said shaft;
   a U-shaped mount having side walls;
   a locking toothed wheel constituted by a toothed rim of an aperture in one of said side walls;
   a plastic bearing mounted on the inside of said one side wall to substantially close the aperture and support one side of said rotatable shaft;
   acceleration of the shaft causing outward movement of the locking means relative to the shaft to move into locking engagement with said locking toothed wheel to lock the belt against further extension.
2. 2. The device of claim 1 wherein the bearing under high pressure can deform. --