CA2158901A1 - Device for tightening a safety belt of a motor vehicle - Google Patents
Device for tightening a safety belt of a motor vehicleInfo
- Publication number
- CA2158901A1 CA2158901A1 CA002158901A CA2158901A CA2158901A1 CA 2158901 A1 CA2158901 A1 CA 2158901A1 CA 002158901 A CA002158901 A CA 002158901A CA 2158901 A CA2158901 A CA 2158901A CA 2158901 A1 CA2158901 A1 CA 2158901A1
- Authority
- CA
- Canada
- Prior art keywords
- piston
- guide pipe
- lock
- propellant
- locking element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/18—Anchoring devices
- B60R22/195—Anchoring devices with means to tension the belt in an emergency, e.g. means of the through-anchor or splitted reel type
- B60R22/1954—Anchoring devices with means to tension the belt in an emergency, e.g. means of the through-anchor or splitted reel type characterised by fluid actuators, e.g. pyrotechnic gas generators
- B60R22/1955—Linear actuators
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
- B60R2022/282—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices using fluids or vico-elastic materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
- B60R2022/286—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices using deformation of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
- B60R2022/288—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices with means to adjust or regulate the amount of energy to be absorbed
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Automotive Seat Belt Assembly (AREA)
Abstract
A drive mechanism has a guide pipe, a piston which is guided in the guide pipe and is driven by a propellant that is generated by a gas generator, and a traction mechanism which connects the piston to the component to be driven.
Description
Field of the Invention The invention pertains to a device for tightening a safety belt of a motor vehicle.
Background of the Invention In a device of this type which is disclosed in German Offenlegungsschrift No.2,249,786, a gas generator is disposed in a piston and the piston is driven by means of a propellant generated by the gas generator. The piston is guided in a guide pipe and can be connected with a safety belt of a motor vehicle via a traction mechanism. A pressure chamber, from-which the propellant generated in the interior of the piston is discharged via at least one outlet opening, is disposed in the guide pipe.
Summary of the Invention The invention is based on the objective of creating a device for tightening a safety belt of a motor vehicle, which device has a more compact construction and which requires a smaller number of components for assembly.
A guide pipe forms a pressure chamber on the end of a piston at which propellant is discharged. In addition, a combustion chamber is formed in the interior of the piston in which the final propellant that provides the driving pressure is formed due to the combustion of the propellant being discharged from the gas generator during the ignition. On the side which is directed towards the interior of the piston and/or the combustion chamber, the gas generator can be equipped for this purpose with a bursting base as is, for example, described in German Patent Application No. P 4228696.4 or European Patent Application No.
93/106542.9.
In addition, the gas generator can be constructed in such a way that the gas is discharged from the gas generator in at least two stages, whereby the gas discharged during the first stage applies a driving pressure onto the pistonwhich is lower as compared to the gas discharged during the ensuing second stage and/or the ensuing stages. A pyrotechnic gas generator of this type is disclosed in German Patent Application No. P 4228696.4. This measure facilitates a controlled adaptation of the pressure profile as well as a reduced ~15~QOl stress on the components to be moved. Initially, a pushing force is applied ontothe resting mass of the components to be moved during the first driving stage.
In the ensuing stage and/or stages, the final pressure is built up due to the increased explosion speed. This results in a reduced stress on the part of the safety belt to be moved during the acceleration process.
The drive mechanism can be used in any instance in which components are moved from an initial position into a final position under a carefully applied traction within a short period of time, e.g., within fractions of a second. Thisdevice can, for example, be used for moving safety shutters or components in a motor vehicle from a normal position into a retracted position. It is, for example, possible, to retract a steering wheel, foot pedals or a safety belt.
An additional reduction of the individual parts to be assembled as well as a reduction in the space requirement is achieved by arranging a return lock on the piston which can be engaged with the inner wall of the guide pipe so as to lock the movement of the piston opposite to the driving direction. This means that the guide pipe fulfils an additional function, namely the function ofa deceleration pipe which cooperates with the return lock on its inner wall.
The return lock preferably is arranged on the end of the piston situated in the driving direction. The traction mechanism preferably is rigidly connectedto the piston at this end of the piston, in particular via a cable pressing withwidened cross section. This measure allows forces acting upon the traction mechanism to be transferred into the guide pipe which is fastened onto the motor vehicle with a short power flux path A preferred application of the invention is used for retracting a seat belt lock of a safety belt. Through the retracting movement of the seat belt lock thesafety belt is tightened by the driven piston around the body of the motor vehicle passenger, for example in an accident, via the traction mechanism which preferably is constructed as a traction cable, so that the safety belt tightener adjoins the body of the motor vehicle passenger. This prevents the body of the motor vehicle passenger from being moved too far forward when the safety belt is blocked in an accident.
Since the tightening movement of the seat belt lock must take place within a few milliseconds, the lock is subject to a high acceleration force during 21~890 1 the driving and the braking at the end of the tightening movement. To avoid sudden braking, especially at the end of the tightening movements, an energy absorber can be provided between the seat blet lock and the reversing arrangement, through which the traction mechanism is led from the drive 5 piston to the seat belt lock; the energy absorber brakes the tightening movement of the seat belt lock, especially at the end of the tightening movement. This energy absorber can consists of an elastic material and can, for example be in the form of a pipe. In particular, the material of the energy absorber is softer than the material of the reversing arrangement. Braking can 10 be achieved by the softer material of the energy absorber being pushed into an opening in the reversing arrangement at the end of the tightening movement, through which the traction mechanism is led. In the process, the soft material of the energy absorber is deformed and used up in braking the driving energy of the seat belt lock..
Brief Description of the Figures The invention is described in detail below with the aid of the embodiments illustrated in the figures. The figures show:
Figure 1 is a cross-sectional view of a first embodiment of the drive mechanism, and Figure 2 is a view partly in cross-section of a second embodiment of the drive mechanism.
Figure 3 schematic view of a further embodiment of the invention in normal operating position; and Figure 4 the embodiment shown in Fig. 3 after the retracting movement of the seat belt lock.
Detailed Description of the Preferred Embodiments The drive mechanisms illustrated in the Figures includes a guide pipe 7 in which is guided a piston 2 that is driven by a propellant. A gas generator 1 is arranged in the interior of the piston so as to realize the drive of the piston 2. Viewed in the driving direction (arrow A) of the piston 2, the gas generator 1 is situated at the front end of the piston 2. The gas generator 1 can be constructed in accordance with European Patent Application No. 93/106542.9, 215~90~
i.e., the gas generator 1 has a bursting base 20 at its propellant outlet side 3.
This base opens once the gas generator 1 ignites. Consequently, the propellant can be discharged into an interior space 4 of the piston. This interior space 4 of the piston is constructed as a combustion chamber. The combustion of the exploding propellant occurs in this combustion chamber.
It is also possible to construct the generator as a two-stage generator as described in German Patent Application No. P 4228696.4, i.e., the gas generator is equipped with explosives of different explosion speeds, whereby the gas of the first stage can be formed primarily by one or more explosives of the ignition device. The ignition preferably is carried out with the aid of an electric ignition device 14 that has a power supply 22. It is also possible to provide a mechanical ignition device.
The interior space 4 of the piston serving as the combustion chamber simultaneously serves for accommodating a cable pressing 17 which has a wider diameter than the diameter of the traction cable that serves as the traction mechanism 15. The cable pressing 17 in addition comprises a support ring 19 which firmly adjoins the inner side of the piston base 18, namely also in the starting position (Figure 1). One or more recesses 5 through which the propellant formed in the interior space 4 of the piston can be discharged is (are) situated in the cable pressing 17, in particular in the support ring 19. The propellants are discharged into a pressure chamber 6. The interior space 4 of the piston, which serves for accommodating the cable pressing 17, simultaneously acts as a combustion chamber towards which the propellant outlet side 3 of the gas generator 1 is directed.
A return lock 9 is situated at the rear end of the piston 2 viewed in the driving direction A. The return lock 9 according to Figure 1 is equipped with anexpandable locking element 10 which consists in this embodiment of several ring segments, e.g., three ring segments. However, it is also possible to construct the locking element as a snap ring. This locking element 10 is guided on a conical projection 11. The conical projection 11 is formed onto the outer side of the piston base 18. The conical projection 1 1 is constructed in a hollow fashion. Its interior is connected to the pressure chamber 6 via leakage openings 23, whereby the outlet opening and/or outlet openings 5 are directed towards said pressure chamber. In the starting position, the conical projection 2i5~
11 is braced on a closure element 8 of the guide pipe 7. This closure element can be constructed as a plastic plug and can form a filter for combustion residues. The other end of the pipe can also be equipped with such a closure element. The locking element 10 can be guided on the conical projection 11 5 with the aid of a peripheral spring element 21 and adjoin a peripheral rubber cushion 24.
The locking element 10 is constructed in such a way that it can be moved freely along the inner wall of the guide pipe 7 in the driving direction A.
When moving the piston opposite to the driving direction A, the locking 10 element 10 is widened by the conical projection 1 1 and engages with the inner wall of the guide pipe such that it locks the movement of the piston. For this, the locking ring preferably is provided with a pointed tip 13. Additional peripheral grooves 12 can be formed in the inner wall of the guide pipe so as to supplement the engagement between the locking element 10 with the guide 15 pipe 7 to lock the movement of the piston. The cross section of these peripheral grooves 12 is constructed in such a way that the pointed tip 13 can engage with the locking element in a positive as well as non-positive fashion.
Viewed in the moving direction A, the locking element has a slanted peripheral surface which originates at the peripheral tip 13. This measure facilitates the 20 free movability of the locking element in the moving direction A in the illustrated embodiment.
The traction mechanism 15 which is constructed as a traction cable extends toward the component to be moved through the closure element 8. A
narrowing 26 (Figure 2) is provided in the guide pipe 7 at the end of the pipe 25 in order to limit the movement of the piston 2. The piston 2 moves into this narrowing 26 with its front part 25 that is constructed in a conical fashion, whereby the piston subsequently is decelerated and stopped. As explained previously, the tightened condition is maintained by means of the return lock 9 that engages 30 with the inner wall of the guide pipe 7 so as to lock the movement of the piston. The forces which act upon the traction mechanism 15 are absorbed by the cable pressing 17 fastened onto the piston 2 and transferred into the pipe 7 over a short path via the piston base and the return lock 9. The pipe 7 is mounted to be stationary, e.g., on the body of a motor vehicle.
21589~ 1 Once the piston 2 is decelerated, the cable pressing 17 with the traction mechanism 15 connected thereon continues its movement in the driving direction A of the piston due to its inert mass. In the embodiment shown, a brake 16 in the form of a disk spring is arranged between the cable pressing 5 17 which produces the connection between the piston 7 and the traction mechanism 15. The cable pressing 17 is decelerated by brake 16 during its continued movement in the driving direction A. This measure facilitates a double-stage deceleration at the end of the driving movement.
In the embodiment shown in Figure 2, the return lock 9 which also can 10 act as a return brake consists of roller bodies 27 which adjoin a ring 28 of elastic material in their starting position. The roller bodies 27 are retained in a tapered, annular space which encompasses the piston. The inner side of this space has a slanted surface. This slanted surface is formed by hard shells 29 which encompass a piston part 30 that consists of a soft material, e.g., 15 an aluminum alloy. The other annular limitation is formed by the inner surface of the guide pipe 7.
When moving the piston in the direction of the arrow A, the remain in the position shown in Figure 2. In a return of the piston 2, the roller bodies 27 roller bodies 27 order to prevent are displaced along the slanted surfaces of the 20 hard shells 29 and act as clamping bodies inside of the aforementioned tapered space. It is also possible that the roller bodies are deformed on the inner wallof the pipe 7 and act as a brake.
The traction mechanism 15 which is constructed as a traction cable is connected to a seat belt lock 31 of the seat belt in a motor vehicle which is 25 partially illustrated in the figures. The piston 2 facilitates that the seat belt lock can, for example, be retracted by a distance of 80 mm so that the safety belt is tightened around the body of the motor vehicle passenger.
Fig. 3 and 4 show a further embodiment of the invention. In this embodiment, the example shown in Fig. 1 or Fig. 2 can be used as the drive 30 mechanism in guide pipe 7. As in the example shown in Fig. 2, the traction mechanism 15 constructed as a traction cable is led through a reversing arrangement 32 to seat belt lock 31 of a safety belt for a motor vehicle.
Traction cable 15 is led through a curved opening 36 in reversing arrangement 32. The reversing arrangement 32 is fastened to a fastening point 35 on a ~1S8901 vehicle seat not shown in detail, or on the vehicle body. As explained above, seat belt lock 31 can be retracted by a distance S of about 80 mm through a tightening movement generated by the drive mechanism in guide pipe 7. This tightens the safety belt to the body of the motor vehicle passenger.
Fig. 3 illustrates the situation while a motor vehicle is in normal driving mode. Fig. 4 shows the situation after seat belt lock 31 has retracted. In this position, seat belt lock 31 has retracted by a distance S (Fig. 3). To carry outthe retracting movement, the seat belt lock is subjected to a high-speed in relation to the retracting movement. When this retracting movement is ended suddenly, high acceleration forces are applied to seat belt lock 31 and the associated parts of the seat belt loc, i.e. to forces which can move the lock parts from their set positions. To prevent the abrupt or sudden end of the tightening movement, the shown embodiment in the form of a pipe is provided with an energy absorber 33. This is provided between the seat belt lock and the reversing arrangement 32. In the embodiment shown, the energy absorber 33 in the form of a pipe is fastened to traction mechanism 15, for example by means of clamping. On the underside of seat belt lock 31, a pushing element 34 in the form of a stop is provided. This stop or the pushing element can be formed by the cable pressing with which the traction mechanism 15 constructed as a traction cable is connected. During the retracting movement, seat belt lock 31 is moved along distance S (Fig. 3). The energy absorber 33 in the form of a pipe is inserted by means of the pushing element 34 into the opening 36 of reversing arrangement 32. Since the material of the pipe-shaped energy absorber 33 is softer than the material of reversing arrangement 32, the energy absorber is deformed. The energy thus expanded reduces the kinetic energy which is applied to seat belt lock 31 by the tightener drive in pipe 7.
This causes the energy absorber 33 to brake the retracting movement, especially toward the end of this movement. This braking action means the shock applied to seat belt lock 31 and its components is dampened, so that the forces acting upon the lock components are relatively low, and the risk that they may move from their locking position is reduced or eliminated.
Background of the Invention In a device of this type which is disclosed in German Offenlegungsschrift No.2,249,786, a gas generator is disposed in a piston and the piston is driven by means of a propellant generated by the gas generator. The piston is guided in a guide pipe and can be connected with a safety belt of a motor vehicle via a traction mechanism. A pressure chamber, from-which the propellant generated in the interior of the piston is discharged via at least one outlet opening, is disposed in the guide pipe.
Summary of the Invention The invention is based on the objective of creating a device for tightening a safety belt of a motor vehicle, which device has a more compact construction and which requires a smaller number of components for assembly.
A guide pipe forms a pressure chamber on the end of a piston at which propellant is discharged. In addition, a combustion chamber is formed in the interior of the piston in which the final propellant that provides the driving pressure is formed due to the combustion of the propellant being discharged from the gas generator during the ignition. On the side which is directed towards the interior of the piston and/or the combustion chamber, the gas generator can be equipped for this purpose with a bursting base as is, for example, described in German Patent Application No. P 4228696.4 or European Patent Application No.
93/106542.9.
In addition, the gas generator can be constructed in such a way that the gas is discharged from the gas generator in at least two stages, whereby the gas discharged during the first stage applies a driving pressure onto the pistonwhich is lower as compared to the gas discharged during the ensuing second stage and/or the ensuing stages. A pyrotechnic gas generator of this type is disclosed in German Patent Application No. P 4228696.4. This measure facilitates a controlled adaptation of the pressure profile as well as a reduced ~15~QOl stress on the components to be moved. Initially, a pushing force is applied ontothe resting mass of the components to be moved during the first driving stage.
In the ensuing stage and/or stages, the final pressure is built up due to the increased explosion speed. This results in a reduced stress on the part of the safety belt to be moved during the acceleration process.
The drive mechanism can be used in any instance in which components are moved from an initial position into a final position under a carefully applied traction within a short period of time, e.g., within fractions of a second. Thisdevice can, for example, be used for moving safety shutters or components in a motor vehicle from a normal position into a retracted position. It is, for example, possible, to retract a steering wheel, foot pedals or a safety belt.
An additional reduction of the individual parts to be assembled as well as a reduction in the space requirement is achieved by arranging a return lock on the piston which can be engaged with the inner wall of the guide pipe so as to lock the movement of the piston opposite to the driving direction. This means that the guide pipe fulfils an additional function, namely the function ofa deceleration pipe which cooperates with the return lock on its inner wall.
The return lock preferably is arranged on the end of the piston situated in the driving direction. The traction mechanism preferably is rigidly connectedto the piston at this end of the piston, in particular via a cable pressing withwidened cross section. This measure allows forces acting upon the traction mechanism to be transferred into the guide pipe which is fastened onto the motor vehicle with a short power flux path A preferred application of the invention is used for retracting a seat belt lock of a safety belt. Through the retracting movement of the seat belt lock thesafety belt is tightened by the driven piston around the body of the motor vehicle passenger, for example in an accident, via the traction mechanism which preferably is constructed as a traction cable, so that the safety belt tightener adjoins the body of the motor vehicle passenger. This prevents the body of the motor vehicle passenger from being moved too far forward when the safety belt is blocked in an accident.
Since the tightening movement of the seat belt lock must take place within a few milliseconds, the lock is subject to a high acceleration force during 21~890 1 the driving and the braking at the end of the tightening movement. To avoid sudden braking, especially at the end of the tightening movements, an energy absorber can be provided between the seat blet lock and the reversing arrangement, through which the traction mechanism is led from the drive 5 piston to the seat belt lock; the energy absorber brakes the tightening movement of the seat belt lock, especially at the end of the tightening movement. This energy absorber can consists of an elastic material and can, for example be in the form of a pipe. In particular, the material of the energy absorber is softer than the material of the reversing arrangement. Braking can 10 be achieved by the softer material of the energy absorber being pushed into an opening in the reversing arrangement at the end of the tightening movement, through which the traction mechanism is led. In the process, the soft material of the energy absorber is deformed and used up in braking the driving energy of the seat belt lock..
Brief Description of the Figures The invention is described in detail below with the aid of the embodiments illustrated in the figures. The figures show:
Figure 1 is a cross-sectional view of a first embodiment of the drive mechanism, and Figure 2 is a view partly in cross-section of a second embodiment of the drive mechanism.
Figure 3 schematic view of a further embodiment of the invention in normal operating position; and Figure 4 the embodiment shown in Fig. 3 after the retracting movement of the seat belt lock.
Detailed Description of the Preferred Embodiments The drive mechanisms illustrated in the Figures includes a guide pipe 7 in which is guided a piston 2 that is driven by a propellant. A gas generator 1 is arranged in the interior of the piston so as to realize the drive of the piston 2. Viewed in the driving direction (arrow A) of the piston 2, the gas generator 1 is situated at the front end of the piston 2. The gas generator 1 can be constructed in accordance with European Patent Application No. 93/106542.9, 215~90~
i.e., the gas generator 1 has a bursting base 20 at its propellant outlet side 3.
This base opens once the gas generator 1 ignites. Consequently, the propellant can be discharged into an interior space 4 of the piston. This interior space 4 of the piston is constructed as a combustion chamber. The combustion of the exploding propellant occurs in this combustion chamber.
It is also possible to construct the generator as a two-stage generator as described in German Patent Application No. P 4228696.4, i.e., the gas generator is equipped with explosives of different explosion speeds, whereby the gas of the first stage can be formed primarily by one or more explosives of the ignition device. The ignition preferably is carried out with the aid of an electric ignition device 14 that has a power supply 22. It is also possible to provide a mechanical ignition device.
The interior space 4 of the piston serving as the combustion chamber simultaneously serves for accommodating a cable pressing 17 which has a wider diameter than the diameter of the traction cable that serves as the traction mechanism 15. The cable pressing 17 in addition comprises a support ring 19 which firmly adjoins the inner side of the piston base 18, namely also in the starting position (Figure 1). One or more recesses 5 through which the propellant formed in the interior space 4 of the piston can be discharged is (are) situated in the cable pressing 17, in particular in the support ring 19. The propellants are discharged into a pressure chamber 6. The interior space 4 of the piston, which serves for accommodating the cable pressing 17, simultaneously acts as a combustion chamber towards which the propellant outlet side 3 of the gas generator 1 is directed.
A return lock 9 is situated at the rear end of the piston 2 viewed in the driving direction A. The return lock 9 according to Figure 1 is equipped with anexpandable locking element 10 which consists in this embodiment of several ring segments, e.g., three ring segments. However, it is also possible to construct the locking element as a snap ring. This locking element 10 is guided on a conical projection 11. The conical projection 11 is formed onto the outer side of the piston base 18. The conical projection 1 1 is constructed in a hollow fashion. Its interior is connected to the pressure chamber 6 via leakage openings 23, whereby the outlet opening and/or outlet openings 5 are directed towards said pressure chamber. In the starting position, the conical projection 2i5~
11 is braced on a closure element 8 of the guide pipe 7. This closure element can be constructed as a plastic plug and can form a filter for combustion residues. The other end of the pipe can also be equipped with such a closure element. The locking element 10 can be guided on the conical projection 11 5 with the aid of a peripheral spring element 21 and adjoin a peripheral rubber cushion 24.
The locking element 10 is constructed in such a way that it can be moved freely along the inner wall of the guide pipe 7 in the driving direction A.
When moving the piston opposite to the driving direction A, the locking 10 element 10 is widened by the conical projection 1 1 and engages with the inner wall of the guide pipe such that it locks the movement of the piston. For this, the locking ring preferably is provided with a pointed tip 13. Additional peripheral grooves 12 can be formed in the inner wall of the guide pipe so as to supplement the engagement between the locking element 10 with the guide 15 pipe 7 to lock the movement of the piston. The cross section of these peripheral grooves 12 is constructed in such a way that the pointed tip 13 can engage with the locking element in a positive as well as non-positive fashion.
Viewed in the moving direction A, the locking element has a slanted peripheral surface which originates at the peripheral tip 13. This measure facilitates the 20 free movability of the locking element in the moving direction A in the illustrated embodiment.
The traction mechanism 15 which is constructed as a traction cable extends toward the component to be moved through the closure element 8. A
narrowing 26 (Figure 2) is provided in the guide pipe 7 at the end of the pipe 25 in order to limit the movement of the piston 2. The piston 2 moves into this narrowing 26 with its front part 25 that is constructed in a conical fashion, whereby the piston subsequently is decelerated and stopped. As explained previously, the tightened condition is maintained by means of the return lock 9 that engages 30 with the inner wall of the guide pipe 7 so as to lock the movement of the piston. The forces which act upon the traction mechanism 15 are absorbed by the cable pressing 17 fastened onto the piston 2 and transferred into the pipe 7 over a short path via the piston base and the return lock 9. The pipe 7 is mounted to be stationary, e.g., on the body of a motor vehicle.
21589~ 1 Once the piston 2 is decelerated, the cable pressing 17 with the traction mechanism 15 connected thereon continues its movement in the driving direction A of the piston due to its inert mass. In the embodiment shown, a brake 16 in the form of a disk spring is arranged between the cable pressing 5 17 which produces the connection between the piston 7 and the traction mechanism 15. The cable pressing 17 is decelerated by brake 16 during its continued movement in the driving direction A. This measure facilitates a double-stage deceleration at the end of the driving movement.
In the embodiment shown in Figure 2, the return lock 9 which also can 10 act as a return brake consists of roller bodies 27 which adjoin a ring 28 of elastic material in their starting position. The roller bodies 27 are retained in a tapered, annular space which encompasses the piston. The inner side of this space has a slanted surface. This slanted surface is formed by hard shells 29 which encompass a piston part 30 that consists of a soft material, e.g., 15 an aluminum alloy. The other annular limitation is formed by the inner surface of the guide pipe 7.
When moving the piston in the direction of the arrow A, the remain in the position shown in Figure 2. In a return of the piston 2, the roller bodies 27 roller bodies 27 order to prevent are displaced along the slanted surfaces of the 20 hard shells 29 and act as clamping bodies inside of the aforementioned tapered space. It is also possible that the roller bodies are deformed on the inner wallof the pipe 7 and act as a brake.
The traction mechanism 15 which is constructed as a traction cable is connected to a seat belt lock 31 of the seat belt in a motor vehicle which is 25 partially illustrated in the figures. The piston 2 facilitates that the seat belt lock can, for example, be retracted by a distance of 80 mm so that the safety belt is tightened around the body of the motor vehicle passenger.
Fig. 3 and 4 show a further embodiment of the invention. In this embodiment, the example shown in Fig. 1 or Fig. 2 can be used as the drive 30 mechanism in guide pipe 7. As in the example shown in Fig. 2, the traction mechanism 15 constructed as a traction cable is led through a reversing arrangement 32 to seat belt lock 31 of a safety belt for a motor vehicle.
Traction cable 15 is led through a curved opening 36 in reversing arrangement 32. The reversing arrangement 32 is fastened to a fastening point 35 on a ~1S8901 vehicle seat not shown in detail, or on the vehicle body. As explained above, seat belt lock 31 can be retracted by a distance S of about 80 mm through a tightening movement generated by the drive mechanism in guide pipe 7. This tightens the safety belt to the body of the motor vehicle passenger.
Fig. 3 illustrates the situation while a motor vehicle is in normal driving mode. Fig. 4 shows the situation after seat belt lock 31 has retracted. In this position, seat belt lock 31 has retracted by a distance S (Fig. 3). To carry outthe retracting movement, the seat belt lock is subjected to a high-speed in relation to the retracting movement. When this retracting movement is ended suddenly, high acceleration forces are applied to seat belt lock 31 and the associated parts of the seat belt loc, i.e. to forces which can move the lock parts from their set positions. To prevent the abrupt or sudden end of the tightening movement, the shown embodiment in the form of a pipe is provided with an energy absorber 33. This is provided between the seat belt lock and the reversing arrangement 32. In the embodiment shown, the energy absorber 33 in the form of a pipe is fastened to traction mechanism 15, for example by means of clamping. On the underside of seat belt lock 31, a pushing element 34 in the form of a stop is provided. This stop or the pushing element can be formed by the cable pressing with which the traction mechanism 15 constructed as a traction cable is connected. During the retracting movement, seat belt lock 31 is moved along distance S (Fig. 3). The energy absorber 33 in the form of a pipe is inserted by means of the pushing element 34 into the opening 36 of reversing arrangement 32. Since the material of the pipe-shaped energy absorber 33 is softer than the material of reversing arrangement 32, the energy absorber is deformed. The energy thus expanded reduces the kinetic energy which is applied to seat belt lock 31 by the tightener drive in pipe 7.
This causes the energy absorber 33 to brake the retracting movement, especially toward the end of this movement. This braking action means the shock applied to seat belt lock 31 and its components is dampened, so that the forces acting upon the lock components are relatively low, and the risk that they may move from their locking position is reduced or eliminated.
Claims (26)
1. A drive mechanism comprises a guide pipe, a piston which is guided inside the guide pipe and can be driven by means of a propellant that is generated by a gas generator and a traction mechanism which connects the piston with a part to be driven and with a pressure chamber that is formed in the guide pipe, whereby the propellant which is generated in the interior of thepiston is discharged from the pressure chamber via at least one outlet opening in the piston, wherein:
the gas generator (1) which is arranged in the piston (2) has a propellant outlet side (3) which is directed towards an interior space (4) of the piston and opened by propellant ignited in the gas generator, and the interior space (4) of the piston is constructed as a combustion chamber for the propellant which is discharged from the gas generator and is provided with at least one outlet opening (5).
the gas generator (1) which is arranged in the piston (2) has a propellant outlet side (3) which is directed towards an interior space (4) of the piston and opened by propellant ignited in the gas generator, and the interior space (4) of the piston is constructed as a combustion chamber for the propellant which is discharged from the gas generator and is provided with at least one outlet opening (5).
2. A device according to claim 1, wherein the pressure chamber (6) is closed at an end of the guide pipe (7) by a closure element (8) which is constructed as a filter for combustion residues.
3. A device according to claim 1, wherein a return lock (9) is arranged on the piston and can be engaged with the inner wall of the guide pipe (7) to prevent movement of the piston in a direction opposite to the driving direction.
4. A device according to claim 3, wherein the return lock (9) is arranged at an end of the piston in the driving direction.
5. A device according to claim 3, wherein the return lock (9) is provided with a locking element (10) which can be expanded radially with respect to the axis of the guide pipe (7), the locking element being guided on a conical projection (11) of the piston (2) wherein the locking element (10) can be moved freely on the inner wall of the guide pipe (7) in the driving direction, and wherein the locking element can, if the piston moves opposite to the driving direction, be expanded by the conical projection (11) to engage with the inner wall of the guide pipe (7) and lock the movement of the piston.
6. A device according to claim 5, wherein the conical projection (11) is hollow and comprises at least one outlet opening (5).
7. A device according to claim 5, wherein the inner wall of the guide pipe (7) is provided with-at least one peripheral groove (12), with which the lockingelement (10) can be engaged when expanded radially.
8. A device according to claim 5, wherein the locking element (10) has a pointed tip (13) which engages with the inner wall of the guide pipe (7) during expansion of the locking element.
9. A device according to claim 5, wherein that the locking element (10) is attached to the conical projection (11 ) under a prestress.
10. A device according to claims 1, wherein the gas generator (1) is constructed so that the propellant is discharged in at least two stages, with the gas discharged during the first stage applying a driving force to the piston (2)which is smaller than the gas discharged during the ensuing second stage and/or ensuing stages.
11. A device according to claim 1, wherein the gas generator (1 ) comprises an electric ignition device (14).
12. A device according to claim 1, wherein the traction mechanism (15) comprises a traction cable and is rigidly connected with the piston (2) via a cable pressing (17) which has a larger diameter than the traction cable.
13. A device according to claim 1, wherein the piston (2) is braced on the closure element (8) during normal operation.
14. A device according to claim 1, wherein the guide pipe (7) is braced in a stationary fashion.
15. A device according to claim 1, wherein the at least one outlet opening (5) is formed by a recess in a support ring (19) that is arranged on the cable pressing (17), whereby said support ring is rigidly braced on a base of the piston in an interior portion of the piston.
16. A device according to claim 5, wherein the conical projection (11 ) is formed on the exterior of a base (18) the piston.
17. A device according to claims 1, wherein the traction mechanism (15) on the piston is guided in the driving direction and decelerated at the end of the driving movement of the piston (2).
18. A device according to claim 17, wherein a brake (16) which decelerates movement of the traction mechanism (15) relative to the piston (2) in stopped position is provided between the piston (2) and the cable pressing (17).
19. A device according to claim 1, characterized in that the traction mechanism (15) is led through a reversing arrangement (32) and connected with a seat belt lock (31).
20. A device according to claim 19, characterized in that between the seat belt mechanism (31) and the reversing arrangement (32) is provided an energy absorber 933) which brakes the tightening movement of the seat belt lock (32) in the direction of the reversing arrangement (32).
21. A device according to claim 20, characterized in that the end of the tightening movement is braked by the energy absorber (33).
22. A device according to claim 20 or 21, characterized in that the energy absorber (33) is fastened to the traction mechanism (15) and consists of an elastic material.
23. A device according to one of claims 19 to 22, characterized in that a pushing element (34) is provided on the seat belt lock (31), which pushes the material of the energy absorber (33) into an opening (36) of the reversing arrangement (32), through which the traction mechanism (15) is led.
24. A device according to one of claims 20 to 23, characterized in that the energy absorber (33) is constructed as a pipe.
25. A device according a claim 24, characterized in that the energy absorber (33) constructed as a pipe is conical in shape.
26. A device according to claim 5, wherein the return lock is acting as a return brake having roller bodies which are retained in a tapered, annular spaceencompassing the piston, said annular space has an inner slanted surface formed by hard shells along which the roller bodies can be displaced.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/310,445 US5519997A (en) | 1993-09-22 | 1994-09-22 | Device for tightening a safety belt of a motor vehicle |
| US08/310,445 | 1994-09-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2158901A1 true CA2158901A1 (en) | 1996-03-23 |
Family
ID=23202527
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002158901A Abandoned CA2158901A1 (en) | 1994-09-22 | 1995-09-22 | Device for tightening a safety belt of a motor vehicle |
Country Status (3)
| Country | Link |
|---|---|
| KR (1) | KR100395179B1 (en) |
| CA (1) | CA2158901A1 (en) |
| MX (1) | MX9504017A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005016691A2 (en) | 2003-07-25 | 2005-02-24 | Key Safety Systems, Inc | Seat belt pretensioner with energy dissipating wire cable |
| US11192520B2 (en) * | 2018-02-22 | 2021-12-07 | Volkswagen Aktiengesellschaft | Seat belt device for a vehicle seat |
-
1995
- 1995-09-20 MX MX9504017A patent/MX9504017A/en unknown
- 1995-09-22 KR KR1019950031420A patent/KR100395179B1/en not_active IP Right Cessation
- 1995-09-22 CA CA002158901A patent/CA2158901A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005016691A2 (en) | 2003-07-25 | 2005-02-24 | Key Safety Systems, Inc | Seat belt pretensioner with energy dissipating wire cable |
| US11192520B2 (en) * | 2018-02-22 | 2021-12-07 | Volkswagen Aktiengesellschaft | Seat belt device for a vehicle seat |
Also Published As
| Publication number | Publication date |
|---|---|
| KR100395179B1 (en) | 2003-11-10 |
| MX9504017A (en) | 1997-05-31 |
| KR960010407A (en) | 1996-04-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |