BELT PRETENSIONER FOR A SAFETY BELT
DESCRIPTION OF THE INVENTION The invention relates to a belt pretensioner with the characteristics of the main idea of claim 1. In the normal operation of a vehicle, the safety belt is supported relatively tightly to the body of the passengers of the vehicle, in an accident presents the danger that the passenger's body, despite the locking of the automatic winding shaft, can move too far forward, also the layers of the belt band are wound on the axis of the automatic reel in a way relatively tight, so that loosening of the belt despite the blocking of the winding shaft, can lead to a strong overtaking of the passenger by a film reel effect. Patent document EP 0629,531-A1 discloses a device for operating pyrotechnic rotation of an automatic winding shaft for winding the safety belt, which has two plunger-shaped discharge bodies that are movable by the driving force of pyrotechnic charges in straight or curved guide paths. The drive bodies have gears in the form of a toothed bar, which can be coupled with REF: 26660 a cogwheel of the winding shaft, so that it combs with this and transforms the longitudinal movement into a rotation of the gearwheel of the winding shaft. winding. On ignition of the driving load of the second drive body, it can be controlled in its initiation, in such a way, that the two driving bodies drive the gear wheel of the winding shaft in a temporal sequence. An apparatus is known from DE-44,29,731-A1 for the transmission of a pulse driving movement of the belt pre-tensioner to a belt coil of a safety belt retractor. The apparatus is constructed as a turning device and especially as a planetary apparatus with a hollow wheel disposed fixed in place, and at least one planetary wheel, which acts on the pre-tensioner or belt tensioner impeller, as well as a wheel planetary, which is engageable with the belt coil or is fixedly fixed rotatable. The thrust of the planetary wheel is carried out with the help of an impulse of the belt tensioner which is constructed as a gas generator and, through a gas conduction channel, drives a piston that is connected by a rod to the axis of the planetary wheel. The hollow wheel, the wheel itself sun and planetary, have external dentures that are attached to each other. With the gas generator on, it rolls by the thrust movement generated by the planetary wheel on the fixed hollow wheel in place. With this, the planetary wheel or properly sun will rotate simultaneously. In the use of two planetary wheels they are joined with a coupling, so in a simultaneous ignition exert a common thrust movement. However, the planetary apparatus requires an important construction size that makes a compact arrangement in an automatic safety belt retractor difficult. The present invention therefore proposes the objective of creating a device with the characteristics of the main idea of claim 1, improving its compact construction and its ability to function. That objective is achieved by a belt tensioner or belt tensioner with the features of claim 1. Advantageous embodiments of the invention are pointed out in the subclaims. While in the aforementioned state of the art, the speed and length of the driving body, which moves tangentially along the cogging of the winding shaft, determine the speed of rotation and the rotation angle of the winding shaft, in the driver of the winding shaft. belt according to the invention only a planetary wheel that leads in a path of movement as short as possible and saving place in the boxwhere the central sun wheel is rotated by a suitable selection of the size ratios, from the planetary wheel to the sun wheel, the necessary tightening path of the belt or the rotation of the winding shaft necessary for this can be achieved , without an additional transfer device between the sun wheel and the winding shaft. By means of the drive units ignited in succession, a generation of distributed driving forces is produced along the path of motion, acceleration competitions adjustable by the ignition characteristics. The sun wheel can be coupled to the winding shaft through a coupling, for example described in DE-4327134-A1, DE-4418438-A1. The introduction of force and movement in the planetary wheel takes place for the benefit of the purpose pursued by means of a crank, a disc or a similar element that is concentrically placed on the wheel of the sun in the box or mounted in a rotatable way. a tang of the sun wheel. This crank, extends radially outward through the sun wheel and represents in this section a support for the planetary wheel, so that this can run on the gear in the box, and thus the sun wheel can be put on rotation. In a second lever arm of the crank disk, at least one grip position is provided, in which the two drive units one after the other, or also temporarily overlapping in periods of time, grip transmitting the torque to the forces and movement. A shaping of the invention is particularly advantageous, wherein the first drive unit after a certain determined movement path triggers a lighter for the driving load of the second unit. With this, an operating safety and an exact ignition in time is guaranteed, since exclusively the behavior of movement of the first driving unit is determinant for the ignition behavior, so that other control parts capable of failing are no longer needed. . The solution can be based on different physical principles, where a mechanical trigger is favorably used for the intended purpose in which a part of the direct drive unit or through an interconnected element acts on a lighter, or a pressure shot, in which the gaseous pressure of the first charge causes the ignition in the expansion space. The plunger may be provided with a sealing element. In this way it is achieved that the plunger if it is adjusted for example, with another adjustment, that is, with a large set in the guide, or if the unit in a plunger piece, articulated connecting rod can perform a pendulum movement, without However, it must be sufficiently etized with respect to the space of the driving gas. Such a sealing element is preferably a sealing element made of synthetic material according to the German model certificate DE-29514068.2-U1. The guides can be arranged in the plane of the sun wheel according to the proportions of the place in the box. Beside the two driving units, at least one other driving unit acting on the crank disk can be provided in the background and in the temporary synchronized sequence be activated before the first driving units. The invention will now be described by means of exemplary embodiments referring to the drawings. Where it shows: FIGURE 1, in a plan view a schematic representation of a crankshaft tensioner or squeeze according to the invention in the starting position; FIGURE 2, in a plan view according to FIG. 1, the belt presser in a first phase of movement due to the impulse by a first drive unit; FIGURE 3, in a plan view according to FIG. 1, the belt tightener in a second phase of movement; FIGURE 4, in a plan view according to FIG. 1, the belt retractor in a third phase of movement with drive by a secondary drive unit;
FIGURE 5, in a plant figure according to FIG. 1, the belt tightener in a fourth movement phase; FIGURE 6, in a plan view according to FIG. 1, the belt retractor in an extreme position; FIGURE 7, in a plan view according to FIG.
3, another embodiment of the belt tensioner; and FIGURE 8, in a plan view the representation of the overlapping movement phases of another embodiment. An exemplary embodiment of a belt tensioner or belt tensioner (see Fig. 1), contains a box 1, the part of the automatic safety belt retractor, (nd shown), is set laterally, in Figs. the belt presser is in a sectional view, for example, in a separating plane of two halves of the box or in a plane for placing a cover. A central gear or sun wheel 2 is placed in the box 1, coaxially to a winding shaft of the automatic safety belt retractor mounted rotatably and engageable with the winding shaft through a known coupling. On the axial pin 3, of the sun wheel 2, a crank or crank disk 4 is rotatably mounted. The one support section 5, of the crank disk 4, projecting radially from the sun wheel 2, is has provided a perforation in which a pin 6 of a planetary gear 7 is taken in a rotatable manner, so that the planetary wheel 7 can be mounted rotatably in the plane of the sun wheel 2, in gear with this. In box 1, an internal gear 9, arranged in the form of a circular arc and pointing towards the sun wheel 2, whose radial distance from the central axis 8, is provided concentrically to the central axis 8 of the sun wheel 2, is it selects such that the planetary wheel 7, in a rotational movement of the crank disk 4, in a direction opposite to the movement of the clock, runs in the internal gear 9, under its own rotation, and on the other hand by gear with the sun wheel 2, rotate it in the opposite direction to the hands of the clock. In box 1, a primary driving unit 10, and another secondary driving device 11, an articulated connecting rod rod unit having a piston 12, and an articulated rod 13, and forming part of the primary driving unit 10, is also provided. placed in a longitudinal guide 14, which extends inwards in an inclined manner from a corner area 15, of the box 1. In such a way that the plunger 12 is arranged in the corner area 15, and limits an expansion space 16, at the end of the longitudinal guide 14, where a current channel 17, of a hollow chamber 18, where a driving load 19, of a first gas generator 20, of the primary driving unit 10 is disposed. The hollow chamber 18 is constructed between the internal gear 9 and the outer side 21 of the box 1 inside the box 1. The articulated connecting rod 13 of the rod unit 12 is pivotably mounted on a bearing pin 22, in the plunger 12. At its free end 23, opposite the plunger 12, has the articulated bar 13, a support pin 24, which rests in a primary grip position 25, in the form of a depression or recess 26, in a section 27, of the crank disk 24. The recess 26 essentially opens in the peripheral direction towards the articulated rod-plunger unit 12, 13, so that a movement of the plunger 12, and rod 13, is transmitted by the support pin 24, producing a rotational movement of the crank disk 4, in the opposite direction to the clock hands. The support pin 24 moves in a circular arc, while the articulated connection bar 13, with respect to the piston 12, in a pendulum movement, the support pin 24, is put in its position in the recess 26, with an angle of 150 °, with respect to the axial pin 6, of the planetary gear 7, in the position of exit or preparation of the belt presser shown in Fig. 1, the ignition of the primary gas generator 20 is performed, after the triggering of a sensor (not shown), by electrical or mechanical methods, this is known from the state of the art, and therefore will not be described in detail. The produced flow gas flows through the current channel 17, in the expansion space 16, and pushes forward the piston 12, in the longitudinal guide 14, (see Fig. 2). Here it places the bar 13, the crank disk 4, in rotation which in turn moves the planetary wheel 7, in a circular path around the sun wheel 2, the wheel 7, which rolls next to the internal gear 9, sets in rotation to the sun wheel 2, which now transmits the movement to the winding shaft to tighten the safety belt, by following the rotation of the sun wheel is coupled with the winding shaft of the automatic reel of the safety belt. In the position shown in Fig. 2, there is the crank disk 4, deflected by an angle of 37.5 °. The secondary drive unit 11 (see Fig. 2) has a unit 30, 31, which has a piston 30, and an articulated connecting rod 31, which unit extends in a longitudinal guide 32, which is inwards inclined from a neighboring corner area 33, (in Fig. 2, bottom left), of the box and approximately in the direction of the planetary wheel 7, received in such a way that the plunger 30, remains in the corner area 33, and limits a expansion space 34, into which a current channel 35 opens, of a hollow chamber 36, where a driving load 37 is disposed, of a secondary gas generator 38. The hollow chamber 36, constructed in box 1, limits with one of its end regions 39, in the longitudinal guide 14, of the primary drive unit 10, and extending approximately in the direction of the piston 30, of the unit 30, 31, articulated connecting rod-plunger. The articulated connecting rod 31, of the piston-rod unit 30, 31, is pivotably mounted with a support pin 40, on the piston 30, at its free end 41, opposite the piston 30, a grip position is formed. secondary in the form of a notch of the type of a long hole 42, which opens on the longitudinal side of the bar 31, towards the bar 13, of the primary drive unit 10, and is suitable for receiving a pin 43, which is placed in the grip section 27 of the crank disk 4, in a direction parallel to the central axis 8, with an angular distance of approximately 20 to 30 °, from the primary grip position 25. In the position shown in FIG. 2, the plunger 12, and the connecting rod 13, still in a driving movement of the crank disk 4, the connecting rod 31, is tilted in a pick-up position against the pin 43, which approaches and in this position tensed for example, with a spring, which rests on the support pin 40, against the piston 30.
Following the course of the movement (see Figures 2 and 3) rotates the plunger-connecting rod unit 12, 13 to the crank disk 4 further, where the tang 43 seizes in the recess 42 of the elongated hole type, and rests on a front surface 44 fitted to spigot 43, and thus the connecting rod 31 scale to the position shown in figure 3 8 shows a rotation of crank disk 4 around an angle of 75 °), where also piston 30 moves forwardly around a small section in the longitudinal guide 32. A stop (not shown) limits the plunger 12 in its forward movement in the position shown in Figure 3. In a defined position before reaching this position an activation takes place. mechanical side of the thrust face 37 of the secondary gas generator 36 by means of an ignition edge 45 of the plunger 12, which strikes a hit bolt 46 of the secondary gas generator 38. The driving gas produced uce flows through the current channel 35 to the expansion chamber 34 and pushes the plunger 30 together with the bar 31 accelerating them forward, so that the connecting rod 31 in relation to the spike 43 moves faster and thus the spike 43 in the recess 42 remains behind in relation to the connecting rod 31 and rests on a rear supporting surface 47 for another transmission of forces (see Figure 4). The driving gas that continues to flow to the expansion chamber 34 moves to the piston and rod unit 30, 31 through the position shown in Figure 5 (showing a rotation of the crank disk 4 about an angle of 112.5 °) to the position shown in Figure 6, in which the rotation of the crank disk 4 is limited by a stop or by the presence of the planetary wheel 7 next to an end wall 48. in this extreme position the crank disk 4 has rotated with respect to the starting position, 150 °. In a transmission ratio or in a relation between the number of teeth of the planetary wheel 7 to the sun wheel 2 of i = 0.3, the rotation and tilting movement of the planetary wheel 7 takes place at an angle of rotation of the planetary wheel 7. Solar wheel 2 of 487 ° and the relationship movement necessary to tighten the belt of the winding shaft without an intermediate transmission device is fulfilled. In the exemplary embodiment shown in FIG. 7, the ignition charge of the secondary gas generator 38 is ignited by means of a gas ignition apparatus 50, which has a branched pressure pipe 51 of the longitudinal guide 12. and an ignition piston 52 disposed at the end of the pressure conduit 51 to ignite the driving load of the second gas generator 38. The pressure conduit 52 branches to such position from the guide 14, which the plunger 12 leaves the conduit free. of pressure 51 at a defined and optimal moment for the continuous course of the movement. The embodiment shown in Figure 8, whose movable parts are shown in several successive positions of the movement course, essentially corresponds to the structure of the belt retractor described above, but differs in the type of the two plunger units - articulated connecting rod 12, 13 or 30, 31, which here contain a rigid arrangement in one piece of the connecting rod 13 and 31 in the respective pistons 12 or 30. The piston is conically constructed in the longitudinal direction, with which it can cooperate with the swinging or pendulum movement of the piston-rod unit, which for example, is perfectly recognizable in the positions indicated with 12 'and 13'. The gas generators are not shown in Figure 8. The sealing of each piston 12, 30 with respect to the respective guide 14 or 32 can take place by a separate sealing element in the piston (see for example the sealing elements 60). and 61 in Figure 8) or by the same plunger, which in that case is constructed so that, due to the pressure of the booster gas, it is slightly widened as necessary. The longitudinal guides 14, 32 for the piston 12, 30 can be formed by guide tubes, which are placed in the recesses provided therefor in the box 1 or in the two box halves and by means of their closed cross section they produce an improved sealing in the partial plane of the box. In FIG. 5 a guide or guide tube of this type 62 is shown schematically, by way of example. The gas generators can be integrated in the guide tubes, in order to optimize the sealing of the gas under pressure. The internal gear or toothing 9 can also be instead of integral part of the box 1, also a part placed in the box 1, which is made of a material with a higher mechanical strength than that of the box material, and that is easily manufactured as a separate part. On the plunger floor 63 of one or both plungers
12 or 30 an additional load 64 can be placed (see for example the representation in Fig.5), which is turned on by the driving load of the corresponding gas generator and thereby can provide an additional driving force to the plunger, which leaves perform special force developments. Especially in the one-piece configuration of the plunger and the articulated connecting rod, shown in FIG. 8, an additional impeller load can be provided in a hollow central space of the piston and, if necessary, also in the bar.
The ignition of secondary gas generator 38 can instead < by the plunger 12 of the primary drive unit 10, also performed by a striking knockout (not shown) inserted in the crank disk 4, which acts on a knocking or shock bolt of the gas generator at a defined time of the course of the movement. The toothing or internal gear 9 can be limited to a small angular area compared to that shown in the figures, so that the planetary wheel 7 in its initial position shown in Figure 1 is without grip with the internal gear 9, and therefore the solar wheel 12 can rotate freely, so that a direct coupling of the solar wheel 2 to the winding shaft of the safety belt automatic is possible without an intermediate switching of a coupling to allow a movement of the belt before firing the belt presser. The same goes for the extreme position of the planetary wheel shown in Fig. 6, in which a smooth wall area without internal gear 9 can guarantee the free rotation of the planetary wheel 7 and with that of the solar wheel 2 and the belt. The arrangement of the longitudinal guides and the gas generators in the box and their positions on opposite sides can be varied between certain limits, as long as the compact conformation represented of the belt tensioner or belt tensioner is maintained. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers. Having described the invention as above, property is claimed as contained in the following: