JP3969525B2 - Pretensioner and related improvements - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pretensioner, and more particularly to a pretensioner for use in a safety belt such as an automobile safety belt.
[0002]
[Prior art]
Proposed to have a pretensioner attached to the safety belt of the car, and this pretensioner works in response to a signal from a sensor that reacts to an impact or other accident condition to hold the occupant firmly in the seat Has been.
[0003]
[Problems to be solved by the invention]
In order to reduce the forward momentum relative to the seat that joins the occupant, the occupant is secured with a safety belt before sitting. For example, if the occupant is rocking and wearing bulky clothing, the seat belt is actually very loose, and if an accident occurs, the seat belt is equipped with a pretensioner. Otherwise, the seat occupant moves forward a substantial distance before the safety belt secures the seat occupant.
[0004]
A lightweight and relatively inexpensive pretensioner mechanism is desired.
[0005]
[Means for Solving the Problems]
According to the invention, a pretensioner is provided for supplying tension to a safety belt, said pretensioner comprising a sealed pressure vessel containing compressed gas, which further comprises a piston and at the same time the piston. An explosive unit suitable for injecting gas into the pressure vessel to move the piston, which causes the piston to extend out of the pressure vessel and reacts to the movement of the piston beyond the pressure vessel, at least one of the elements. The tension is applied to the safety belt, and the components connected to or related to the safety belt are moved to apply tension to the safety belt.
[0006]
Preferably, the pressure vessel is a pressure cylinder, one end of which is sealed with a breakable foil, the other end of the pressure vessel is closed by a closing device associated with the explosion unit, and the piston is in its motion Is arranged to break the foil.
[0007]
Conveniently, the piston is of a hollow tubular type, in which there is at least one opening that communicates between the interior of the piston and a space between the piston and the pressure vessel.
[0008]
Conveniently, the opening formed in the piston is located outside the pressure vessel when the piston is fully extended from the pressure vessel, and the compressed gas in the pressure vessel and in the piston can be exhausted into the outside air. In position.
[0009]
Conveniently, a sealing ring is provided in contact with the foil, the sealing ring having a diameter that is less than or equal to the outer diameter of the piston.
[0010]
Preferably, the explosive device is contained in the closed part in a manner protruding into the pressure vessel, the inner projecting part having an opening that is initially sealed by a breakable foil.
[0011]
Conveniently, the piston defines a chamber in communication with the pressure cylinder.
[0012]
In one embodiment, the piston is formed by a hollow tube member that is initially folded inwardly into the pressure vessel.
[0013]
Conveniently, the means responsive to the movement of the piston comprises a plunger arranged to be engaged by the piston in accordance with the movement, and a guide tube for guiding the movement of the plunger, said plunger comprising at least one said Elements are involved.
[0014]
In one embodiment, the plunger is connected to one end of a wire or other flexible elongate element that is the component associated with the safety belt.
[0015]
In another embodiment, the plunger has two opposite ends, each of which is connected to a wire or other elongated element that is connected to each component associated with each safety belt.
[0016]
In a further modified embodiment, the plunger is provided with a pulley wheel and the like, which engages a wire or other elongated flexible element, one end of which is fixed inside the piston. And the other end is connected to the component associated with the safety belt.
[0017]
In order that the invention may be more readily understood and other features thereof will be appreciated, the invention will now be described in the form of examples with reference to the accompanying drawings.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1 of the accompanying drawings, there is provided a pretensioner device including a unit 1 which will be described in detail below, which device is adapted to supply tension to a wire or cable 2, and the wire or cable 2 is connected directly or indirectly to a buckle 3 which is adapted to receive a tongue 4 attached to a safety belt 5. It can be seen that when tension is applied to the wire 2 by the unit 1, the buckle 3 is moved in the direction of the tension applied to the safety belt. Thus, it is believed that the device operates in a manner similar to previously proposed pretensioners.
[0019]
Unit 1 includes a pressure cylinder 10 containing compressed gas. The lower end of the pressure silencer 10 is provided with a neck 11 with a thread on the outer surface that terminates in an inwardly-facing tubular flange 12 defining an opening 13, which is like a fragile metal foil. Sealed by a foil 14. An elastic sealing ring such as rubber is provided in the neck in direct contact with the flange, and the inner diameter of the sealing ring 15 is slightly smaller than the diameter of the opening 13 defined by the flange 12.
[0020]
The upper end of the cylinder 10 is closed by a lid 16 defining a central hollow tubular projection extending into the cylinder 10, the projection 17 having a slightly smaller diameter than the diameter of the cylinder 10. Initially, the hollow cylindrical protrusion 17 terminates in a lower opening 18 that is sealed by a foil 19 that may be made of metal. Within the hollow cylindrical protrusion 17 is included an explosive device adapted to receive and operate a signal from a sensor 21 that reacts to parameters indicative of an accident or accident condition such as intrinsic deceleration.
[0021]
A hollow piston device 22 is included in the cylinder 10. Piston device 22 includes a hollow tube body 23 extending along an axis having a lower end closed by a lid cap 24. A surface 25 which is the lower surface (in the direction shown in the accompanying drawings) of the lid cap 24 has a conical shape. The surface of the cap 24 on the cylinder side may be provided with a recess or groove extending in the axial direction. The outer diameter of the lid cap 24 and the outer diameter of the tube body 23 of the piston 22 are the same or slightly smaller than the inner diameter defined by the sealing ring 15. The upper end portion of the pipe body 23 of the piston 22 slides on the hollow cylindrical protrusion 17 provided on the upper lid 16. The upper end of the tube body is provided with a flange 26 that extends radially outward. The flange 26 is provided with a plurality of holes 27, and the main pipe body 23 of the piston 22 is provided with at least one hole 28 formed therein. The piston (as will become clearer from the description below) is capable of axial movement downward relative to the cylinder 10 in the illustrated direction. By providing a device such as a ratchet (not shown), the piston is prevented from moving substantially in the opposite (eg upward) direction.
[0022]
The pressure cylinder 10 is filled with a gas such as an inert gas at a high pressure by introducing a gas through a filling hole (not shown) in the upper lid 16. The holes are attached after the cylinder 10 is filled with gas. Due to the presence of the holes 27 and the flange 26, the high pressure gas is present in a relatively small space above the flange 26 and below the upper lid. Due to the presence of the holes 28, the high-pressure gas exists in the hollow interior of the pipe body 23 of the piston 22, and at the same time, exists in an annular space surrounding the piston device 22. The axial recesses or grooves in the cylindrical surface of the cap 24 bypass the seal 15 so that high pressure gas is reliably present in the space between the lower surface 25 of the cap and the foil 14 thanks to these recesses or grooves. Will come to do. For the gas, leakage from the high pressure tube is prevented by a foil 19 that seals the hole 18 formed in the upper lid 16 and a foil 14 that seals the hole 13 defined by the neck 12. Since the piston 22 is entirely within the pressure tube 10 and the entire surface of the piston is exposed to the gas within the pressure tube, the gas does not exert any force that would cause or cause the piston to move.
[0023]
The neck 11 of the pressure tube 10 is screwed into a threaded seat 29 formed on a connection unit 30 that connects the pressure cylinder 10 to a receiving tube 31. The sheet defines a hole that is aligned with the hole 13 of the neck 11. A plunger 32 is attached to one end of the receiving tube 31. The plunger 32 is also provided with a pressure plate 34, and a conical recess corresponding to the conical outer surface of the lower lid cap 24 provided on the pipe body 23 of the piston device 22 is provided on the upper surface thereof. The plunger 32 is located at one end of the receiving tube 31 that directly contacts the hole 13 closed by the foil 14.
[0024]
A stop 35 is provided on the connector 30 to hold and secure one end of the wire 2. Stop 35 is positioned adjacent to guide post 36 having a concave outer surface similar to that of pulley wheel 37. That is, the wire 2 passes through the stop 35, passes through the guide post 36, partially passes around the pulley wheel provided on the plunger 32, and passes through the pulley wheel 37 provided on the connector 30.
[0025]
When the sensor 21 detects an accident, a signal is transmitted to the explosive unit 20, and the explosive material in the explosive unit 20 is ignited to generate hot gas. Referring to FIG. 2, it can be seen that FIG. 2a shows the components of the high-pressure pipe 10 before the accident occurs. That is, the component is in the same position as the relative position shown in FIG.
[0026]
Referring to FIG. 2 b, when the explosion unit 20 generates hot gas, the foil 19 that seals the hole 18 is first broken, and high-pressure gas is injected into the hollow tube body 23 of the piston 22. This starts the piston. The piston 22 moves downward in the axial direction (in the direction shown in FIG. 1). Immediately after the piston begins to move downward, the conical lower surface of the lower lid cap breaks the foil 14. As the cap 24 moves downward, a recess or groove in the cap pushes down the seal 15. Then, the seal 15 meshes with the outer surface of the main body 23 of the piston 22 so as to be sealed. When the piston moves further downward, the gas initially stored in the tubular space between the pipe body 22, the piston and the inside of the pressure cylinder 10 passes through the hole 27 of the flange 26 and enters the space between the flange 26 and the lid 16. Flows in. This slows the movement of the piston device, so that the piston device does not move at an excessive speed. As the piston device moves further downward, the flange 26 moves to a position below the lower end of the hollow cylindrical projection provided on the upper lid 16. At this stage, the explosion unit 20 will still generate gas.
[0027]
The piston device passes through a sealing ring that forms a substantially airtight seat with the piston outer surface. This prevents a large amount of gas leakage from the pressure cylinder along the outer wall of the piston device.
[0028]
As soon as the lower lid cap 24 penetrates the foil 14, the initial filling of the compressed gas in the cylinder 10 and the gas produced by the explosion unit 20 effectively act on the piston 22 and drive the piston downward. The piston 22 moves further downward until the piston 22 protrudes more completely from the lower end of the pressure tube 12.
[0029]
Even when the piston 22 reaches the position shown in FIG. 2c, the hole 28 is located above the seal 15 so that a large amount of gas leakage to the outside air is prevented. This, combined with a ratchet that prevents the downward movement of the piston, helps to ensure that the pretensioner effect is maintained for as long as possible.
[0030]
Referring to FIGS. 3a and 3b, it can be seen that FIG. 3a shows the position of the plunger in the receiving tube 31 before the occurrence of the accident condition. FIG. 3b shows the same components after the piston device 33 has been moved to a fully extended position as shown in FIG. 2c. It can be seen that the lower lid cap engages the pressure plate 34 on the plunger 32 and moves the plunger 32 downward in the receiving tube 32. The receiving pipe always secures an unobstructed space in front of the plunger. When the plunger 32 moves downward in the receiving tube, the wire 2 is pulled through the pulley 37 and the pulley 33. This device is arranged such that for every 1 cm of movement of the plunger 32, the cable 2 is pulled into the receiving tube by approximately 2 cm. In this embodiment of the invention, the receiving tube is provided with a cross-section with a circular center and two diametrically extending radial projections each sized to receive a portion of the wire 2.
[0031]
It can be seen that when the plunger 32 moves axially through the central portion of the receiving tube 31, the wire of the cable 2 is received in the oppositely protruding portion provided for that purpose.
[0032]
FIG. 4 shows a variant implementation of the invention in which a single wire or cable 40 is provided, each end of which is adapted for connection to a respective buckle for receiving a respective tongue provided on each seat belt. Some of the embodiments are illustrated. In this embodiment, the connector 30 is provided with a pulley wheel similar to the above, and at the same time, a second pulley wheel is provided instead of the guide post 36. Plunger 32 may be provided with pulley wheel 33, or it may be provided with a fixed wheel or post. A portion of the wire adjacent to the fixed wheel or post 33 is coupled or fixed to the post or wheel.
[0033]
It is understood that the embodiment shown in FIG. 4 operates in the same manner as the embodiment of FIG. 1, and tension is applied to both ends of the wire 40 so that two seat belts can be pretensioned simultaneously.
[0034]
Referring now to FIG. 5, a modified embodiment of the invention is shown in which a pressure cylinder variant is used and the length of the wire drawn into the receiving tube is equal to the distance traveled by the plunger. A single wire is drawn into the receiving tube by the plunger.
[0035]
In the embodiment shown in FIG. 5, a threaded neck 51 is provided on the outer surface at the lower end of the pressure cylinder 50 in contact with the compressed gas. The neck 51 terminates at a lower end having a radially inward flange 52 defining a hole 53, which is sealed by a foil 54, such as a metal foil. A sealing ring 55 is arranged inside the neck 51 so as to be related to the upper part of the inward flange 52, and this sealing ring has an inner diameter slightly smaller than the diameter of the hole 53.
[0036]
The upper end of the pressure cylinder 50 is closed by a hollow lid plug 56 having a cylindrical protrusion 57 extending toward the inside of the pressure cylinder 50, the protrusion 57 having an outer diameter substantially equal to the inner diameter of the pressure cylinder 50. . The protrusion 57 defines a hole 58 at its lower end, which is sealed by a foil, such as a metal foil 59. Housed within the hollow lid plug 56 is an explosive unit 60 adapted to receive a signal from a sensor responsive to parameters such as acceleration exceeding a predetermined acceleration, indicating an accident condition.
[0037]
The pressure cylinder 50 includes a piston device 61 including a hollow tube main body 62, the lower end of which is closed by a lower lid cap 63, and the lower surface of the lid cap 64 has a conical shape 64. The outer diameter of the lid cap 64 of the tube body 63 is substantially equal to the inner diameter of the ceiling 55. The upper end of the pipe main body 62 of the piston 61 is closed by a hollow cap 64 including a ring-shaped ring 65 mounted on the top of the pipe main body 62, and the hollow cap is fitted to the upper end of the pipe main body 62 by a downward friction. Has a closed hollow tube projection 66 and also has a downward axially extending flange 67 having an outer diameter substantially equal to the inner diameter of the pressure tube 50.
[0038]
The hole 68 is formed in the side wall of the tube body 62 in contact with the hollow cap 64. Another hole 69 is provided in the lower portion of the projection 66 received in the tube body 62.
[0039]
The neck 51 is threadedly received in a thread sheet 70 formed on the connector 71 by screw-thread coupling, which connects the pressure cylinder to the receiving tube 72. A plunger 73 is accommodated in the upper end of the receiving tube, and a conical recess corresponding to the conical protrusion 64 provided on the lower surface of the lid cap 63 is provided on the upper surface thereof. A pulley wheel 75 is provided on the connector 71. The cable has one end fixed to the plunger 73 by a fastener 77, and the wire 76 passes through a pulley wheel 75 and is connected to a buckle equivalent to the buckle 3 shown in FIG.
[0040]
The pressurized gas cylinder will flow through the described holes 68 and 69 and fill the piston device 61 and the space surrounding the piston device 61.
[0041]
With the development of the explosion unit 60 of the embodiment shown in FIG. 5, the high pressure gas will first destroy the foil 59 closing the hole 58, and then the high pressure gas will be sent into the hollow cap 64. This will start the piston 61 downward. The conical lower surface of the lid cap 63 will break the foil 54 closing the hole 53 and then engage the conical sheet 74 defined on the plunger 73. When the foil 54 is broken, not only the gas from the explosion unit 60 but also the force for pushing the piston device 61 out of the pressure pipe 50 by the compressed gas originally present in the pressure cylinder is applied to the piston device.
[0042]
When the piston device moves downward, the gas originally present in the annular space between the pipe body 62 and the pressure cylinder 50 of the piston device flows into the hollow interior of the piston body 62 through the hole 68 and the hollow cap. And the upper lid plug 56 flows into the space of increased volume through the hole 69.
[0043]
When the piston device moves downward, the plunger 73 moves along the receiving tube 72 while applying tension to the wire 76. When the piston is in the fully extended position, the gas from within the pressure tube 50 is then released into the outside air through a hole 68 that will be located beyond the sealing ring 55.
[0044]
FIG. 6 shows an effective modification of the embodiment of FIG.
[0045]
In the embodiment of FIG. 6, the top lid plug 56 has been modified to include a radially outer skirt having an associated skirt with a lower end portion 82 tapered inwardly to press and seal the outer surface of the pressure cylinder tube 50. A flange 80 is provided on the top lid plug. A hole 83 communicating with a chamber 84 defined by a skirt 81 is provided in the wall of the pressure cylinder 50. The remaining components of the embodiment shown in FIG. 6 are identical to the corresponding components shown in FIG. The embodiment of FIG. 6 contains the larger amount of pressurized gas in this embodiment and is the same as the embodiment of FIG. 5 except that this gas flows out of chamber 84 through hole 83 when the apparatus is deployed. It is considered to operate in the style of The gas will exit the pressure cylinder when the piston device 61 is excluded.
[0046]
Turning now to FIGS. 7 and 8, a further variation of the invention is described. In this embodiment, the piston device is formed from a tubular element folded inwardly in a flexible manner.
[0047]
Referring to FIG. 7, the lower end of the pressure cylinder 90 is provided with a neck 91 with an inward radial flange 92 defining a hole 93 sealed with a foil 94 such as a metal foil at the lower end. Yes. A sealing ring 95 is provided which rests on the radially inward flange 92 and defines a central hole having a diameter slightly smaller than the diameter of the hole 93. The neck 91 is provided with a screw-thread on the outer surface.
[0048]
The upper end of the pressure cylinder 90 is closed by a lid 96. The lid 64 has an attached cylindrical projection 97 having an outer diameter smaller than the inner diameter of the pressure tube 90, and the lower end of the projection 97 defines a hole 99 sealed with a foil 100 such as a metal foil. Ends in a radially inward flange 98.
[0049]
An explosion unit 101 is mounted on the lid 96 and is provided to extend into an associated projection 97.
[0050]
A piston device 102 is provided. The piston device includes a flexible tubular sleeve 103. One end 104 of the sleeve 103 is firmly attached using a mounting ring 105 at a location adjacent to the joint between the neck 91 and the pressure cylinder 90. The tubular element 103 extends upward in the direction shown in FIG. 7 from the neck 91 to the piston adjacent to the cylindrical projection 97 attached to the upper lid 97. The tubular element is then folded inside to extend inside the first mentioned portion of the tubular element, with the lower surface ending with a conical lower lid cap 106. The outer diameter of the portion adjacent to the lower lid cap and the tubular member 103 is slightly smaller than the size of the inner hole determined by the sealing ring 95.
[0051]
In the initial state as shown in FIG. 7, the piston device 102 is completely contained by the foil 94 and in a pressure tube sealed by the foil 100.
[0052]
During deployment of the apparatus as shown in FIG. 7, gas from the igniter 101 breaks the foil 100 and the gas is introduced into the lower portion of the tubular element 103 adjacent to the lower lid cap 106. The lid cap 106 is then biased downward, causing the foil 94 to break. The pressurized gas in the pressure tube 90 and the gas from the igniter thus mix and force the piston device 103 into a fully expanded state. As the lower lid cap 106 continues to move downwards, the entire length of the tubular element 103 expands straight through the sealing ring 95 until the device is fully expanded as shown in FIG.
[0053]
In the preceding description, it is clear that various types of pressure cylinders and piston devices have been described, and various types of plungers and associated mechanisms that apply tension to one or more cables. Obviously, each type of pressure cylinder and piston device as described above is used for each of the various plunger mechanisms.
[0054]
In the described embodiment, the ignition device and pressure cylinder combination is relatively small and relatively light. The use of a combination of pressurized gas and gas from the igniter gives a good power to weight ratio. In the preferred embodiment of the present invention, the wire associated with the seat belt buckle is given a relatively gentle initial motion, and the tension applied to the seat belt is rather "gentle" rather than a disturbing and abrupt method. Join in the way.
[0055]
It will be apparent that in one embodiment of the present invention, various techniques are used to change the operating characteristics of the device. For example, the size of the various holes is chosen such that the gas flow through the holes achieves certain operating characteristics. For example, the hole 26 of the flange 27 is appropriately sized and an appropriate number of holes is provided. Similarly, the holes 28 made in the body of the piston 22 are of an appropriate size and one or more such holes can be provided. The interior of the piston is divided into a plurality of chambers using a transverse diaphragm. The volume of these chambers and the size of the holes in the diaphragm are appropriately selected. The chamber located directly above the foil 29 and directly below the igniter 20 has a selected volume. The initial volume in the cylinder 10 placed on the flange 26 has a predetermined volume, and the volume directly under the flange 26 and surrounding the piston body 23 in the cylinder 10 also has a selected volume. In some embodiments, there is a small gap between the lid cap 24 and the sealing ring 15 to provide a flow path with a predetermined cross-sectional area, which is unique between the cap lower surface 25 and the breakable foil 14. Volume is delimited. All of these volumes are also chosen to obtain the proper operating characteristics.
[0056]
Thus, by selecting the size of the hole and the volume of the chamber, the speed of movement of the piston can be adjusted, and the moment when the piston moves to the fully expanded position can be adjusted.
[0057]
Although the present invention has been described with reference to an embodiment in which motion is imparted to the seat belt buckle to provide pre-tension to the seat belt, in a modified embodiment of the present invention, the motion is engaged with a portion of the seat belt. It can be applied to a retractor for a device adapted to generate tension by deflecting the belt, that is, a seat belt terminal fixing device.
[0058]
In the present specification, “including” means “including or composed of”, and “including” means “including or composed”.
[0059]
In the foregoing description, the following claims, or the accompanying drawings, if necessary, in its specific form, or using a means for realizing the disclosed characteristics, or a method or process for obtaining the disclosed results Thus, the characteristics described and disclosed may be utilized to implement the present invention in its wide variety of forms, either separately or in any combination of these characteristics.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view and a partial schematic view of an embodiment of the invention.
FIGS. 2a, 2b and 2c depict the components of FIG. 1, showing the various stages during operation of the pretensioner.
FIGS. 3a and 3b show components of the embodiment of FIG. 1 in two opposing states.
4 is a component diagram of a modified embodiment of the invention depicted correspondingly to FIG. 3;
FIG. 5 is a diagram of another embodiment of the invention depicted corresponding to FIG.
FIG. 6 depicts components of a modified embodiment of the invention.
FIG. 7 depicts components of yet another modified embodiment of the invention.
8 is an embodiment view of FIG. 7 after actuation, depicted correspondingly to FIG.
[Explanation of symbols]
5 Safety belt
10 Pressure cylinder
13 opening

Claims (12)

A pretensioner for applying tension to a safety belt, comprising a sealed pressure vessel pre-filled with a predetermined pressurized gas, the pressure vessel also including a piston, and an ignition gas is injected into the pressure vessel And an ignition device that operates to move the piston to extend from the pressure vessel by applying a tension to at least one element in response to the movement of the piston extending from the pressure vessel. The pretensioner comprising means for moving a component connected to or interlocking with the safety belt to apply tension to the safety belt. Pressure vessel a pressure cylinder, one end of the pressure cylinder is sealed with fracture of the foil, the other end is closed by a lid which is linked to the ignition device, to break the foil by piston moves The pretensioner according to claim 1, adapted to   3. A pretensioner according to claim 1 or 2, wherein the piston is of a hollow tube shape and has at least one hole forming communication between the piston interior and the space between the piston and the pressure vessel.   The position of the hole formed in the piston is such that when the piston is fully extended from the pressure vessel, the hole is outside the pressure vessel, and the pressurized gas in the pressure vessel and the piston is released into the atmosphere. The pretensioner according to claim 3, wherein the pretensioner is a position where   5. A pretensioner as claimed in any one of claims 2 to 4, comprising a sealing ring adjacent to the foil, the sealing ring having a diameter equal to or smaller than the outer diameter of the piston.   6. The ignition device according to any one of claims 2 to 5, wherein the igniter is included in a portion of the lid protruding inside the pressure vessel, the portion protruding inward is initially sealed by a breakable foil. The pretensioner described in 1.   The pretensioner according to any one of claims 1 to 6, wherein the piston defines a small chamber communicating with the pressure vessel.   The pretensioner according to any one of claims 1 to 7, wherein the piston is formed by a hollow tubular member that is folded into the pressure vessel so as to protrude into itself.   The means responsive to piston movement includes a plunger in a position to be fitted and moved by the piston, and a guide tube for guiding the movement of the plunger, wherein the plunger is associated with the at least one element. The pretensioner according to any one of 8.   The pretensioner of claim 9, wherein the plunger is connected to one end of a wire or other flexible elongate element connected to the component associated with the safety belt.   The plunger is connected to a wire or other elongated element having two opposite ends, each of the ends being connected to a respective component associated with a respective safety belt. Pretensioner.   The plunger includes a pulley wheel, and the pulley wheel or the like is attached to a wire or other elongated flexible element that is connected to the above-described component that has one end fixed in place and the other end tied to a safety belt. The pretensioner according to claim 9, which is connected.

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