WO1987001664A1

WO1987001664A1 - Belt coiler for back tensioner

Info

Publication number: WO1987001664A1
Application number: PCT/DE1986/000365
Authority: WO
Inventors: Hans-Otto Kock; Bernd Lacher
Original assignee: Allied Engineering Company S.A.
Priority date: 1985-09-17
Filing date: 1986-09-13
Publication date: 1987-03-26
Also published as: DE3533126A1; EP0236381A1

Abstract

Double synchronized safety belt coiler for back tensioners, consisting of a pinion (40) fixedly attached axially to a coiling shaft and a locking catch (18) rotatably supported at a distance from the pinion (40), the locking catch (18) having also teeth (41) for engagement in the pinion (40) whereby the rotary engagement movement of the locking catch (18) has a direction of rotation opposite to that of the pinion, together with a control plate (20) which can be entrained after the triggering of sensors (25, 30) by the pinion (40) their pre-control elements (22, 24), a control cam (36) and a control pin (37) engaging in the control cam (36). To ensure that in the locked position when the back tensioner is released the lock can be automatically disengaged in a short time, without loosing the locking function thereby, the invention provides that the control pin (37) is arranged on the locking catch (18) and the control cam (36) is arranged on the control plate (20) and that the control cam (36) is inclined over its whole length at an angle of at least 10o in relation to a tangent which at the relevant interface of the control cam (36) is applied against an arc of cercle passing around the rotation axis (38) of the pinion (40).

Description

Belt retractor for back tensioners

The invention relates to a double-synchronized seat belt retractor for rear tensioners, consisting of a gear wheel axially fixedly connected to a winding shaft and a pawl rotatably mounted at a distance from the gear wheel, which also has a toothing for engagement with the gear wheel, the engaging rotary movement of the pawl being one relative to that Gear rotation movement has the opposite direction of rotation, with a control plate which can be carried along by triggering sensors from the gear via pilot control elements, a control curve and a control pin engaging in the control curve. Such a seat belt retractor is known. In general, such seat belt retractors have two different sensors, one of which reacts to the vehicle's tilting, rocking or jerking movements and the other to accelerated unwinding of the belt. When triggered, the sensors engage so-called pilot control elements, which create a connection with a driving wheel, for example a gear wheel, which is attached to the winding shaft. The entrained control disk then in turn actuates a pawl or a locking hook, which thereby comes into engagement with a gearwheel, which is also axially fixedly connected to the winding shaft, and blocks it and thus also the winding shaft. The pawl and pawl differ in that the direction of rotation of the pawl coincides with the direction of rotation of the control disk or the gearwheel when the control disc engages in the gearwheel, whereas with a pawl the direction of rotation of the pawl engaging just reverses that of the gearwheel or which is the control disk triggering the rotary movement of the pawl. Synchronized or double-synchronized seat belt retraction he are characterized in that a control pin or a control cam is attached to the control disc at a certain, fixed distance from the respective pilot elements, which or which the hook or controls the pawl into the gear at a more or less precisely defined angle with respect to the tooth position of the gear.

In this way it is achieved that the tips of the teeth of the pawl and the gear do not coincide, which on the one hand knocks the pawl back through the gear and on the other hand a strong load or even destruction of the control disk and / or the pilot elements can occur. The fixed distance between the pilot element and the control cam or control pin therefore enables the teeth of the locking hook or the locking pawl to be securely inserted into the gearwheel without the aforementioned disadvantageous effects occurring. The prerequisite is, however, that the control pin is guided in the control cam largely without play.

In the aforementioned seat belt retractor with all the features mentioned at the outset, the control cam is designed as a groove in the pawl, while the control pin is firmly attached to the control disc. Because of the already mentioned sense of rotation of the pawl relative to the gearwheel and the associated control disk, it follows that the control cam on the pawl must have a radially inward-pointing component in order to insert the pawl into the gearwheel, since the distance of the control pin from the axis of rotation of the control disk remains constant while the distance of the control pin to the pin or the axis of rotation of the pawl must decrease during the control process.

Starting from a constant angular velocity of the control disc, it can be seen that the pivoting-in movement of the locking pawl must then proceed accelerated, since the control pin covers the same kegs at the same time, but this movement takes place on an increasingly smaller radius with respect to the axis of rotation of the pawl, so that the rotary motion and the pawl inevitably accelerates must follow.

However, as soon as the tip of a tooth of the pawl abuts the flank or the bottom of a tooth of the gearwheel, the rotational movement of the pawl is stopped, while the rotational movement of the gearwheel, the control disk moved by the gearwheel and the control pin attached to the control disk is continued until the teeth of the pawl and the gear mesh with each other.

The teeth of the gearwheel and the pawl are generally asymmetrical and have a flat and a steep flank, the locking forces being absorbed by the steep flanks when the pawl engages in the gearwheel, while the flat tooth flanks provide sufficient hold and sufficient strength of the teeth care, but on the other also cause a corresponding distance between the teeth, so that the introduction of the teeth is even possible. The steep flank of the teeth is necessary so that the pawl is not pushed out of the gearwheel again by the forces acting in the radial direction on flat flanks.

The special tooth shape together with the accelerated swiveling movement of the pawl makes it necessary to carry out the swiveling movement of the pawl in an angular position in which a certain safety distance of the tooth tips of the pawl and the toothed wheel which are moving past one another is maintained. This leads to the movement sequence described above, in which a tooth tip of the locking mechanism first abuts the flat flank or the base of a gear tooth before the steep flanks of the two teeth come into positive engagement with one another after a further rotation of the gear wheel. When the tooth tip of the pawl abuts the tooth flank of a gear tooth, the opposite steep flanks have one because of the tolerances that occur during the manufacture of the individual part While the gear covers this remaining distance on its circumference, the control pin carried over the control disk moves in a circular path about the same axis as the gear by about twice the distance, since its distance from the axis is about twice as large as the gear radius. However, since at the same time the pawl practically does not turn any further, since a tooth tip of the pawl has already applied to the flat flank of a gear tooth, so that the forces occurring during locking are not caused by the pin guided in the control cam or the control disk or pilot elements connected to the pin In all known seat belt retractors of this type, the control cam has a recess tangential in the locked position with respect to the gearwheel axis, into which the control pin can engage while the gearwheel performs the residual rotation described above. Now that so-called retraction devices or tensioners have been developed for such retractors, which tighten the seat belt in a split second in the event of an accident, it must be assumed that such retraction device can also be triggered at a time when the automatic retraction mechanism is just being triggered by the pawl or a blocking hook is blocked.

The rewind tensioner rotates the winding shaft and the gearwheel in the non-blocking direction with great force and very quickly. However, while with a slow winding movement of the winding shaft and the gear the control disc and the control pin attached to it and also the pilot elements are returned to their starting position by springs and thus unlock the system, the winding process by the back tensioner happens so quickly that the control disc and the you connected parts practically remain in their position during the rotation of the gear. However, the pawl is forcibly in the direction of its output via the flat flanks of the teeth of the pawl and the gearwheel would be pushed back, the control pin located in the tangential recess of the control cam being subjected to a large force in the radial direction. However, since the control pin has a fixed distance with respect to the axis, it is either broken off, bent or pushed out of the control curve by the force acting in the radial direction and possibly jammed with the pawl. The control disk and the pilot control elements can also be destroyed or damaged. This can lead to the case that after the back tightening process has been completed, the freely running winding shaft is no longer secured by the locking device, as a result of which the entire belt has lost its securing function.

The invention is therefore based on the object of providing a seat belt retractor for rear tensioners, which is automatically unlocked in the locked position when the rear tensioner is triggered in the short time available without losing its locking function or being damaged in any other way.

This object is achieved in that the Steuerεtift on the pawl and the control cam are arranged on the control disc and that the control curve is inclined over its entire length at an angle of at least 10 ° with respect to a tangent, which in the respective intersection of the control curve with a the axis of rotation of the gear wheel or the control disk struck circular arc is applied to this. From the disadvantages of the known seat belt retractor described at the outset, it can be seen that during the sudden winding movement of the winding shaft and the associated gear, the pawl is forced out of the gear, the control pin, since it is still in the tangential recess of the control cam, a strong one is exposed to force acting in the radial direction, which he can only avoid by breaking, bending or sliding out of the locking curve. As a result, these drawbacks can only be avoided Avoid that the control curve has no tangential recess through which the exclusively radial force on the pin is caused when the pawl is pushed out of the gear. Accordingly, the control curve of the belt retractor according to the invention does not have a tangential recess, but instead is inclined by at least 10 ° with respect to the tangential direction. As a result, the radial force component which acts on the pawl is partially converted into a tangential force component at the edge of the control cam which is inclined towards the tangential direction, as a result of which the guide pin dodges by means of a rotational movement about the axis of rotation of the guide disk and the ring gear, the control disk and the pilot control elements be turned back to their starting position at the same time. This resetting of the control pin and the associated control disc and the pilot elements is thus forced by the backward movement of the gear and the resulting pushing out of the pawl out of engagement with the gear and happens much faster than would be possible by the return spring.

However, in order to be able to dispense with the tangential recess of the control cam present in all known belt retractors of this type, further advantageous design changes are required compared to the known belt retraction systems. These consist in that the control pin is arranged on the pawl and the control cam on the control disk.

Now, as described at the beginning, the control process of the

To effect pawl in the gearwheel with the aid of the control cam arranged on the control disc, the control pin arranged at a fixed distance from the bearing pin of the pawl must be guided along a control curve in such a way that its distance from the axis of rotation of the control disc and the gearwheel decreases continuously. If you put num again, As in the example mentioned above, a substantially constant angular velocity of the gear and the control disc ahead, it can be seen that the control movement of the pawl in the toothing of the gear runs at a continuously decreasing speed. So while the teeth of the gear cover the same distances during the latching process of the pawl at constant angular velocity in the same times, the distance traveled per unit of time of the tip of a tooth of the pawl becomes smaller and smaller in the course of the latching process. In this way it is possible to prevent the pawl teeth from striking the flat flank of the gear teeth before the frictional contact of the steep flanks. It can even be achieved that the frictional contact of the steep tooth flanks is established before the tooth tip of one (or more) pawl teeth (teeth) touches the flat flank of a gear tooth.

In this way, the need for a tangential recess in the control cam has also been avoided.

At the same time, this constructive measure ensures that the control or latching process can be carried out even more precisely and in a better synchronized manner than in the known belt retractors.

The above considerations regarding the control process have been carried out in the event that the radial distance between the tooth tip and tooth base is somewhat larger in the teeth of the pawl than in the case of the gearwheel, as a result of which the tip of a pawl tooth can strike the flat flank of a gear tooth in the first place becomes. The completely analogous considerations in the event that the radial distance between the tooth tip and tooth base is greater for the gear than for the pawl lead to exactly the same consequences and results. In practice you will try your teeth to design both elements essentially the same, whereby more or less randomly one or the other occurs.

In a preferred embodiment of the invention it is provided that over the entire length of the control curve the angle which the control curve includes with the tangential direction is at least 20 °.

In this way, a quick unlocking of the locking mechanism is ensured even if the friction between the control pin and the control cam is greater than in normal cases due to long periods of non-use.

Since the control curve is a slot or a groove the width of the control pin diameter, the angle which the control curve includes with the tangential direction is to be understood as the angle which is at the point of intersection between the longitudinal center line of the control curve groove and one around the axis of the control disk the circle between the tangent at this point and the tangent to the longitudinal center line of the cam groove at this point.

Furthermore, it is provided in the preferred embodiment of the invention that the pawl is arranged in a plane with the gear on a housing plate rotatable about a pin or rivet fastened in the frame outside the gear radius.

Such an embodiment enables easy and quick assembly of the pawl and the other parts.

It is also preferably provided on the belt retractor according to the invention that a hook attached to the housing plate engages around the pawl.

Because the pivot of the pawl in the housing plate is rotatably mounted and the pawl engages in a gear above the housing plate in the gear, a torque is exerted on this pawl when the gear engages in the pawl, which endeavor to turn the pawl out of its rotating plane. Therefore, according to the invention, the pawl is held in its plane of rotation by a hook encompassing it.

Instead, however, it can also be expedient if, according to the invention, the control pin is designed as a rivet projecting through an arcuate slot in the housing plate, the head of which is wider than the slot and is arranged on the side of the housing plate opposite the pawl.

In this way too, the pawl is held in its rotational plane by the control pin, which is designed as a safety rivet on one side.

In the preferred embodiment of the invention it is further provided that the teeth of the pawl have a steep and a flat flank and that the tooth shape of the gear is adapted to the teeth of the pawl.

It is important that not only the steep flank of the teeth that come into engagement with each other, which is loaded during locking, is of the same design, but that the back of the adjacent teeth, which is not loaded during locking, is also designed in a good fit. This rear side, which is not loaded when locking, transmits the power transmission from the gear to the pawl by means of the back tensioning device at the beginning of the back tensioning process, by means of which it is pressed out of the gear, while at the same time the control disc and the control pin are used to reset the control disk and the front control elements. Although a belt retractor is known in which the control cam is arranged on the control disc, the control pin is arranged on a locking hook, whereby the same unfavorable conditions for the movement of the hook as for the belt retractor result due to the rotational movement in the same direction as the gearwheel during the control process with pawl, in which the control cam is arranged on the pawl and the control pin on the control disc. With regard to the accelerating or decelerating control process, the situation with locking hooks is exactly the opposite of that with pawls.

Further advantages, features and possible applications of the present invention result from the following description of a preferred embodiment and the associated drawings. Show it:

1 shows the side view of a belt retractor for tensioners and

2 shows an axial section through the belt retractor of FIG. 1, the broken back tensioner attached to it also being shown.

The seat belt retractor shown as a preferred embodiment in the drawings has the winding axis, generally designated 1, and the ratchet gear 40, which is axially fixedly connected to the latter, in whose teeth the toothing 41 of the pawl 18 can engage, which, via a pin 19 designed as a rivet, on the housing plate 16 is arranged rotatably. The belt retractor or automat also has vehicle-sensitive sensors, namely the inertial mass stored in the housing 28 of the sensor in the form of a hanging or standing pendulum or a ball, the pawl axis 31 provided in the bearing arranged on the housing 28 with a vehicle-sensitive pawl 30 and the pilot lever 22 controlled therefrom. The latter is brought into engagement with teeth of the control wheel 23 in the event of excessive vehicle acceleration by the vehicle-sensitive pawl 30, which is connected to the control plate 20 in such a way that the pilot lever 22 is rotatably mounted on the control plate 20.

Furthermore, the control plate 20 also has an internal toothing 44 into which the control tooth of the belt-sensitive pawl 24 engages in the event of excessive belt webbing acceleration, which in turn is rotatably mounted about a pin 45 which is fixedly connected to the winding shaft. The control of the belt-sensitive pawl 24 is done via a mass carrier 26, on which in turn an inert mass 25 is frictionally attached. The frictional connection between mass carrier 26 and mass 25 is so firm that it acts practically as a rigid connection when the belt is accelerated, as can occur in everyday use of the machine, but on the other hand, the inert mass 25 slides on the mass carrier 26, if the latter the triggering of the back tensioner via the pawl 24 experiences extreme acceleration. In the case of a rigid connection between mass carrier 26 and mass 25, because of the inertia of mass 25, the force acting on pawl 24 during the re-tightening process would be so great that it would probably be destroyed.

In the case of belt belt acceleration, however, such as occurs when a vehicle occupant moves forwards when braking or, for example, in the event of minor rear-end collisions at walking pace, which does not yet trigger the back tensioner, the pawl 24 rotatably mounted on the pin 45 moves with the Winding shaft in the direction of the mass carrier 26, which practically remains in its position due to the large acceleration resistance caused by the inert mass 25 attached to it, so that the pawl 24 is rotated around the pin 45 and thereby engages with the internal toothing 44 of the Control plate 20 comes. A compression spring 27 brings the pawl 24 back into the release position as soon as the belt acceleration falls below a certain value, which depends on the ratio of the force of the compression spring 27 to the total inert mass formed by mass carrier 26 and mass 25.

As soon as the pawl 24 engages in the internal toothing 44 of the control plate 20, this is rotated by the winding shaft via the pawl 24, the toothing 41 of the pawl 18 being brought into engagement with the toothed wheel 40 via the control cam 36 and the control pin 37, and thus firmly with the gear 40 connected winding shaft 1 locks.

The control plate 20 has a spring receptacle 46 for a spring 21, which is supported on a bracket 47 fastened to the housing 16. This pressure-retaining spring 21 moves the control plate 20 after the strain relief of the webbing and, via the control cam 36 and the control pin 37, also the pawl 18 back to its starting position. At the beginning of the resetting process, the gearwheel 40 and the associated winding shaft 1 are also turned back via the toothing 41 of the pawl 18, as long as the pawl 18 and the gearwheel 40 are in engagement with one another.

However, this reset by the pressure retaining spring 21 is comparatively slow. If, on the other hand, the back tensioner is triggered while the pawl 18 and the gear 40 are in engagement with one another, which is quite probable because of the braking preceding an accident, the winding shaft 1 and thus also the gear 40 are rotated back much faster than this by the pressure retaining spring 21 could happen in the manner just described.

If, in such a case, the gearwheel 40 suddenly turns backwards, ie clockwise in FIG. 1, the pawl 18 or its toothing 41 is pushed out of the toothing in the radial direction, as seen from the gearwheel 40, wherein the control pin 37 can dodge in the control cam 36 and thereby turns the control plate 20 back to the starting position. This is possible because the control cam 36 has a sufficiently large radial component over its entire length from the gear 40, since the angle between the longitudinal center line 48 of the control cam 36 at the intersection with a gear circumference with the corresponding circular tangent has an angle of at least 20 ° , preferably includes 30 to 40 °.

In contrast, the control cams in known, comparable machines for the control pin in the state of engagement of the corresponding pawl with the corresponding gear always have a tangential to the circumference of the gear recess, which is shown broken off in the part of the control curve 36 shown in Figure 1 down would connect. In such a case, the control pin 37 could not move in the radial direction, so that the destruction of some components would have to be expected and the back tightening process would also be hindered.

The combination according to the invention of the specific arrangement of a control cam 36 and a control pin 37 using a pawl 18 thus makes it possible not only the pawl 18 but also the control plate 20 without loading the pilot lever 22 due to the reverse rotation of the gearwheel 40, which occurs very suddenly during the tightening process or to move the pawl 24 back into its starting position in a non-destructive manner, so that after the tightening process has been carried out, the automatic belt is still fully functional and the belt's securing function (without a tightener) is retained. This is of importance insofar as the locking function of the automatic belt system must be retained in an accident after the back tensioning process has taken place, since after the rope 4 has been relieved, the winding shaft 1 is no longer held by the back tensioning device and the belt could therefore unwind if the pawl does not click into place. To complete the description of the belt retractor, the insert 32 of the winding shaft is shown in FIG

1, the cap 33 on the right to cover the described mechanism and finally the coil 35 is shown in full.

In addition, FIG. 2 shows the tensioner, which is shown in the upper part, its attachment to the belt retractor and its parts placed on the tensioner:

A holder 13, which holds a gas generator 5 and a cylinder 43, which are connected by means of a T-piece 2, is attached to the housing plate 16 via a rivet 6. The piston 3 is located in the cylinder 43, and the continuous cable 4 runs coaxially in it.

In the left-hand area of the belt retractor shown in FIG. 2, the cable store 7, in which the cable 4 is held wound, is connected at the bottom. In addition, there is a spring cassette 9 for a return spring, not shown, under the cap 8 shown on the left in FIG. 2, and the pulley 10 is mounted coaxially within the cable storage device. With the screw 12 shown at the bottom left in FIG. 2, the parts are then fastened to the housing plate 16, against which the winding shaft 1 is supported via the bearing 14. The axis toothing 15 belongs to the winding shaft 1. On this left you can see the serration 15a, which causes the connection with the rope pulley 10.

Claims

Patent pronouncements

1. Double synchronized seat belt retractor for Rückεtraf fer, consisting of an axially firmly connected with eii.er winding shaft (1) gear (40) and a in

Distance from the gearwheel (40) rotatably mounted pawl (18), which also has teeth (41) for engagement with the gearwheel (40), the engagement rotary movement of the pawl (18) having a direction of rotation that is opposite to the gearwheel rotation movement, with one after the triggering of sensors (25, 30) from the gearwheel (40) via pilot control elements (22, 24), controllable control plate (20), a control curve (36) and a control pin (37) engaging in the control curve (36), characterized that the control pin (37) is arranged on the pawl (18) and the control cam (36) on the control plate (20) and that the control cam (36) is inclined over its entire length at an angle of at least 10 ° with respect to a tangent , which is applied to this circular arc at the respective intersection of the control curve (36) with a circular arc which is turned around the axis of rotation (38) of the gearwheel (40) or control plate (20).

2. Seat belt retractor according to claim 1, characterized in that the pawl (18) rotatable in one plane with the gear (40) on a housing plate (16) about a in the housing plate (16) outside the gear radius fixed pin (19) or rivet is arranged.

3. Seat belt retractor according to claim 1 or 2, characterized in that a on the housing plate (16) attached hook (42) urr-engages the pawl (18).

4. Seat belt scooter according to claim 1 or 2, characterized in that the control pin (37) as a rivet projecting through an arcuate slot of the housing plate (16) is formed, the head of which is wider than the slot and which is anoid on the side of the housing plate (16) opposite the pawl (18).

5. Seat belt retractor according to one of claims 1 to 4, characterized in that the teeth of the pawl (18) have a steep and a flat flank and that the tooth shape of the gear (40) also on the unloaded back of the teeth of the tooth shape of the teeth when locked Pawl is adjusted.