Patent Grant
7543363
This present invention relates generally to a seat belt buckle and more specifically, the present invention relates to a seat belt buckle for use with a seat belt pretensioner.
Seat belt buckles in general must meet many requirements to reliably operate under any and all conditions. One specific requirement for seat belt buckles is to function when used with seat belt pretensioners (i.e., retractor, buckle or anchor pretensioners).
Seat belt pretensioners remove seat belt slack in the event of a predetermined occurrence. When pretensioners are activated this results in a very high acceleration of the webbing and subsequently, the seat belt buckle. An example of a pretensioner is a pyrotechnically actuatable device, which fires a squib wherein a resulting force will remove a predetermined amount of slack from the seat belt webbing secured to the seat belt buckle. Accordingly, and when pretensioners are activated, the seat belt buckle is subjected to a very high acceleration.
Therefore, it is desirable to provide the seat belt buckle with a locking feature or device that is engaged during activation of the pretensioners wherein movement of the release button is limited. Additionally, it is desirable to provide a seat belt buckle with an inertia locking device to maintain a latched condition during activation of the pretensioners.
Disclosed herein is a seat belt buckle for use with a tongue of a seat belt. The seat belt buckle of the exemplary embodiment comprises: a frame portion; a latch being movably mounted to the frame portion for movement between a first position and a second position, the latch being configured to engage a portion of the tongue inserted into the frame as the latch moves from the first position to the second position; an ejector being slidably mounted to the frame portion for movement between a locking position and a release position, wherein movement toward the release position causes an opening force to be applied to the latch in order to move the latch from the second position towards the first position, wherein movement of the ejector towards the release position is caused by movement of a release button movably mounted to the seat belt buckle; an inertia locking device rotatably mounted to the release button for movement between a blocking position and an unblocking position, the inertia locking device being configured for rotation in a plane substantially parallel to a plane of movement of the latch, wherein a portion of the inertia locking device makes contact with the frame and prevents movement of the release button when the inertia locking device is in the blocking position; and a pair of springs integrally formed with the release button, the pair of springs being configured to provide a biasing force to the inertia locking device to rotate the inertia locking device to the unblocking position.
In another exemplary embodiment, a method for limiting acceleration forces applied to a release mechanism of a seat belt buckle is provided, the method comprising: rotatably mounting a mass to a release button of the seat belt buckle by inserting a lobed portion into a receiving area of the release button and positioning a pin of the mass into a pair of openings in the release button, the pin being biased in a first position by a pair of springs integrally formed with the release button, wherein the first position allows the pin to travel through a pair of slots in a frame of the seat belt buckle as the release button is slidably moved with respect to the frame from a locked position to an unlocked position wherein the release button causes a force to be applied to an ejector as the release button moves to the unlocked position and wherein the pin prevents movement of the release button from the locked position to the unlocked position when the mass is rotated from the first position and the pin makes contact with a surface of the frame.
Also disclosed herein is a restraint system for a vehicle. A restraint system for a vehicle, comprising: a seat belt buckle for use with a tongue of a seat belt, the seat belt buckle comprising: a frame portion; a latch being movably mounted to the frame portion for movement between a first position and a second position, the latch being configured to engage a portion of the tongue inserted into the frame as the latch moves from the first position to the second position; an ejector being slidably mounted to the frame portion for movement between a locking position and a release position, wherein movement toward the release position causes an opening force to be applied to the latch in order to move the latch from the second position towards the first position, wherein movement of the ejector towards the release position is caused by movement of a release button movably mounted to the seat belt buckle; an inertia locking device rotatably mounted to the release button for movement between a blocking position and an unblocking position, the inertia locking device being configured for rotation in a plane substantially parallel to a plane of movement of the latch, wherein a portion of the inertia locking device makes contact with the frame and prevents movement of the release button when the inertia locking device is in the blocking position; a pair of springs integrally formed with the release button, the pair of springs being configured to provide a biasing force to the inertia locking device to rotate the inertia locking device to the unblocking position; and a pre-tensioning device for removing slack from the seat belt in accordance with a predetermined event.
In another exemplary embodiment, a release button for use with a seat belt buckle is provided. The release-button comprising: a mass rotatably mounted to the release button for movement between a blocking position and a non-blocking position; a pin depending outwardly from opposite sides of the mass; a pair of receiving areas configured to receive the pin depending outwardly from the mass; a pair of springs integrally molded with the release button, the pair of springs providing a biasing force to rotate the mass into the non-blocking position; and wherein the biasing force must be overcome for the mass to rotate into the blocking position.
The above-described and other features of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.
Disclosed herein is a seat belt buckle for use with a pre-tensioning device. When activated, the pre-tensioning device removes slack from a seat belt or retracts a predetermined amount of seat belt webbing, which is secured to either the seat belt buckle or a tongue of a seat belt. The present invention is also related to commonly owned and assigned U.S. patent application Ser. No. 10/945,308 filed Sep. 20, 2004, the contents of which are incorporated herein by reference thereto.
The seat belt buckle comprises a latch for securing a tongue of the seat belt to the seat belt buckle. The seat belt buckle further comprises a release button that actuates an ejector via a pin and a cantilever member pivotally mounted to the ejector. The ejector is slidably mounted to a frame portion of the seat belt buckle. The ejector is also configured to slide from a locking position to a release position, wherein insertion of the tongue in the seat belt buckle causes movement of the ejector towards the locking position and depression of the release button when the tongue is inserted in the seat belt buckle causes movement of the ejector from the locking position to the release position. In addition, movement of the ejector from the locking position to the release position causes an opening force via a lock bar, the cantilever and a spring to be applied to the latch in order to move the latch from a locking position towards an open position wherein the tongue portion of the seat belt is able to be removed from the seat belt buckle.
The seat belt buckle further comprises an inertia locking device or movable locking member rotatably mounted to the release button for movement between a locking or blocking position and an unlocking or unblocking position, wherein the inertia locking device prevents movement of the release button when the inertia locking device is in the locking position. The inertia locking device is biased or maintained into the unlocking position by a biasing force wherein the inertia locking device is capable of being rotated or moved into the locking position. In accordance with an exemplary embodiment, the inertia locking device is moved into the locking position when the seat belt buckle is subjected to a force that creates a moment in the locking device sufficient to overcome the biasing force applied to the inertia locking device by the spring members thereby causing rotational movement of the inertia locking device such that the pin member of the inertia locking device will make contact with the frame and prevent further movement of the release button.
In accordance with an exemplary embodiment, the inertia locking device via the spring members is moved or rotated back into the unlocking position when the seat belt buckle is no longer subjected to the force that creates the moment in the locking device which overcomes the biasing force of the spring members.
Moreover and in the event of the failure of the spring members providing the biasing force, the inertia locking device and the seat belt buckle frame are configured to allow the inertia locking to be rotated back into its unlocking position. This is achieved by providing cam out surfaces on the frame portion. Thus, and when the seat belt is no longer subject to the force, which creates the moment for rotating the inertia locking device the inertia locking device is capable of being moved back into its unlocking position even though spring members may no longer be in operation for providing the biasing force to the inertia locking device. In addition, and in accordance with an exemplary embodiment, the inertia locking device is configured to be affected or rotate in response to accelerations in two of three axes or directions.
Referring now to
Seat belt buckle 10 and/or tongue portion 12 is also secured to a pre-tensioning mechanism 22 (illustrated schematically by box 22), which in accordance with a predetermined activation event will cause the pre-tensioning mechanism to remove the slack from the seat belt webbing. As illustrated, the pre-tensioning mechanism may be secured to either the seat belt webbing of the tongue portion or the webbing securing the belt buckle to the vehicle or both. Non-limiting examples of pretensioning mechanisms (e.g., retractors and pretensioners for seat belt buckles, seat belts and seat belt anchors) are found in the following U.S. Pat. Nos. 6,340,176; 6,513,747; and 6,572,147 the contents of which are incorporated herein by reference thereto. U.S. Pat. No. 6,725,509, also incorporated herein by reference thereto, illustrates a seat belt buckle. U.S. Pat. No. 6,438,810 also incorporated herein by reference thereto, illustrates a seat restraint buckle assembly also designed for use with seat belt pretensioners that when deployed will cause the seat belt buckle to experience very high accelerations and very rapid decelerations. In one contemplated configuration for use with exemplary embodiments of the present invention, a pyrotechnically activated pre-tensioning device is secured to the seat belt buckle while a retractor is secured to the webbing having tongue portion 12 secured thereto. For example, the retractor may be located at the shoulder of the vehicle occupant while the pre-tensioner is disposed proximate to the vehicle floor panel where the seat is secured thereto.
As illustrated, seat belt buckle 10 comprises an upper housing portion 24 and a lower housing portion 26 and a frame portion 28 received therein. Referring now to
In order to rotate latch 32 into an unlocking position, a spring 38 is positioned between latch 32 and a cantilever 40. Cantilever 40 is pivotally mounted to an ejector 42 slidably received within a pair of the elongated openings 44 disposed in sidewalls 30. Spring 38 is positioned upon a protrusion 44 of latch 32 and a protrusion 46 of cantilever 40. During insertion of the tongue of the seat belt into the frame, the ejector is slid within elongated openings 44 and spring 38 is compressed thereby providing an urging force to cantilever 46 wherein cantilever 46 is rotated about its pivot pins 50, which are rotatably received in complimentary openings 52 in ejector 42.
As cantilever 40 is rotated an arm portion 54 of cantilever 40 urges a lock bar 56 to travel through slots 58 in sidewalls 30. In accordance with an exemplary embodiment slots 58 are “L” shaped to guide the lock bar into its release and locking positions. Of course, other configurations are contemplated to be within the scope of exemplary embodiments of the present invention. Upon insertion of tongue portion 12 into belt buckle 10, ejector 42 is longitudinally slid with respect to frame portion 28 and accordingly spring 38, which is disposed between cantilever 40 and latch 32, is compressed as the tongue portion is slid into the frame portion 28. During this movement latch 32 is rotated into an engaging position via lock bar or pin 56 such that tongue portion 12 is secured within belt buckle 10.
Thus, once the tongue is inserted into the frame of the buckle the tongue contacts and depresses the ejector, which compresses and stores energy in the spring. As the tongue depresses the ejector the latch will rotate through an aperture in the tongue. As the latch is rotated into the latched position the stored energy in the spring translates the lock bar in the slots of the frame to hold the latch in a latched state.
In order to eject or provide an urging force to slide tongue portion 12 out of the belt buckle, ejector 42, which is slidably mounted to frame portion 28 is configured to make contact with a distal end of tongue portion 12 as the same is being inserted into opening 16 of belt buckle 10. In order to slide lock bar 56 within openings 58 and ultimately move latch 32 into its release position, a release button 60 is configured to slidably engage sidewalls 30 while also providing a release force to lock bar 56, via a pair of integral cam surfaces 62. Thus, as release button 60 is depressed, an urging force is applied to the lock bar to slide it in openings 58. This movement will cause an urging force to be applied to the cantilever via lock bar 56 wherein cantilever 40 will rotate and compress spring 38. This movement allows the lock bar to be moved upwardly wherein latch 32 is free to pivot upwardly moving latch portion 36 out of opening 18 and ejector 42 is slid within openings 44 via the spring force of spring 38 thus, tongue 12 is ejected out of the buckle. In addition, the release button is configured to have a pair of cantilevered arms 63 each of which comprises a cam surface for contacting lock bar 56 when the latch is pushed upwardly and the tongue is removed from the seat belt buckle. In accordance with an exemplary embodiment, arms 63 provide a slight contact force to lock bar 56 in order to provide an anti-rattling feature.
Frame portion 28 further comprises an opening 65 in order to facilitate securement of a webbing material 64 that operably connects seat belt buckle 10 to a pre-tensioning mechanism 22. Normal operation or operation without the pretensioner being activated is illustrated in
In order to provide undesired movement of the lock bar within openings 58 (e.g., movement that is not attributable to depression of release button 60 by an individual or other person who is using the seat belt secured thereto namely, the activation of a pre-tensioning device) an inertia locking device 68 is movably or rotatably secured to release button 60. In exemplary embodiment, inertia locking device 68 comprises a rotating mass 70 pivotally secured to release button 60. In accordance with an exemplary embodiment the rotating mass is pivotally mounted to the release button by a lobe portion or integral pin portion 71 that is rotatably received or snapped into a receiving portion 73 of the release button. As illustrated, receiving portion 73 comprises an elongated opening for pivotally receiving pin portion 71 therein. Of course receiving portion 73 may have other configurations depending on the configuration of the lobe portion or integral pin portion 71 of the rotating mass.
In addition, a pin 72 is secured to mass 70. Pin 72 extends outwardly from either side of mass 70 and has its end portions received within openings 74 of the frame portion and openings 75 of the release button. Acting upon the end portions of the pin are a pair of biasing members or leaf springs 76. In accordance with an exemplary embodiment, leaf springs 76 are integrally formed with the release button. Leaf springs 76 are integrally formed with and thus secured to a side wall portion of the release button at one end and a freely movable portion at the other end. Leaf springs 76 are also configured to provide a biasing force in the direction of arrow 77 thus, pin 72 is urged downwardly in openings 75 such that during operator activation of release button 60 (e.g., depression of the release button in the direction of arrow 79) pin 72 is aligned with and will travel linearly within openings or slots 74 of the frame portion. In an exemplary embodiment, the mass is biased into an unblocking position via an urging force applied to pin 72 via leaf springs 76.
In addition, and when the mass and the pin are in the unblocking position more than 50 percent of the diameter of the pin is aligned or positioned with respect to opening 74 such that movement of the release button in the direction of arrow 79 will urge pin 72 into opening 75 (e.g., the curved surface of the pin corresponding to less than half of the diameter of the pin will allow the same to travel into the opening). Of course, other configurations and percentages of pin 72 for facilitating movement of the pin into opening 75 are contemplated to be within the scope of exemplary embodiments of the present invention. In addition, mass 70 may be configured to have a portion depending away from either side, wherein the integral portion is configured to be biased by springs 76 and travel through openings 74 and 75 as well as make contact with cam surface 78.
In accordance with an exemplary embodiment and as a release force is applied to the release button, the release button translates in a linear direction with respect to the frame. During this linear movement, the pin mounted to the rotating mass passes through two pairs of control apertures or openings—one pair being located in the frame and the other being located in the release button. As the release button is depressed the control apertures integral with the release button and the leaf springs react against the pin and cams the rotating mass to a neutral position (e.g., the position illustrated in
As illustrated in
Thereafter, and as mass 70 has rotated slightly clockwise pin 72 will no longer make contact with spring 76 and travel in opening 74 in the direction of arrow 79. The lack of contact of spring 76 will prevent any unnecessary frictional forces caused by pin 72 making contact with the edges of opening 74 as the pin travels therethrough (
After the rotation of the mass, the biasing force of leaf springs 76 will define an uncompressed position of springs 76 wherein pin 72 and spring 76 are spaced from each other. Thereafter, the pin and button 60 with mass 70 will travel linearly in the direction of arrow 79 until the latch is released and the tongue is ejected from the seat belt buckle.
In accordance with an exemplary embodiment and referring now to
In accordance with an exemplary embodiment, the inertia forces acting on the seat belt buckle due the pre-tensioning devices will also act on the rotating mass. As such, the rotating mass will rotate into a blockout position with respect to the control apertures (e.g., openings 74) integral with the frame. Since the lock bar acts in conjunction with the release button, a latched state of the buckle will be maintained by preventing translation of the release button in the direction of arrow 79.
In accordance with an exemplary embodiment openings 75 of the release button are slotted openings or channels having an open top and a nearly vertical edge facing an angularly positioned edge, wherein the angular positioned edge is located closer to the spring members and the cam surfaces in order to facilitate the movement of pin 72 therein. Also, and in accordance with an exemplary embodiment release button 60 is formed from an easily molded material such as plastic thus biasing members or springs 76 are also plastic and integrally molded therewith.
The inertia blockout of the release button and lock bar is maintained because inertia forces acting on the rotating mass are greater than the inertia forces tending to force the pin out of the blockout position (e.g., movement away from the cam surface).
In accordance with an exemplary embodiment, the mass will have a center of gravity substantially below a rotating mass pivot point or the securement point of the rotating mass to the release button.
During activation of the pretensioner, the seat belt buckle experiences acceleration in all three axes X, Y & Z (illustrated in
Thus, and when belt buckle 10 is subjected to a force, which creates a moment in inertia locking device 68, mass 70 and the ends of pin 72 overcome the biasing force of springs 76 and rotate into a locking position wherein the ends of pin 72 make contact with cam surfaces 78 of the frame portion and movement of the release button is prevented. Thus, unwanted movement of latch 32 will not occur. This feature is illustrated in
In accordance with an exemplary embodiment, the rotating mass blockout theory is explained as follows, wherein:
Ff=Frictional Force
Frm=Force of Rotating Mass
Rpb+lb+rm=Reaction Force of the Push Button+Lock Bar+Rotating Mass
Fpb+lb=Force Pushbutton+Lock Bar
ΣMa=0=+M1−M2−M3
M1<M2+M3
Rpb+lb+rm×L1<Frm×L2+Ff×L3
In accordance with an exemplary embodiment M1<M2+M3 thus, the mass will rotate into the blocking position.
Accordingly, and as shown in the above example, the inertia forces will rotate the mass into the blockout position illustrated in
It is also noted that cam or contact surfaces 78 are configured to have a cam out feature in the event of a failure of the leaf springs. Thus, a fail-safe mode of operation is provided. For example, after a pretensioner has been deployed, the occupant must be able to operate the release button and detach the buckle. In the event of a leaf spring failure, the frame's openings are designed with a positive cam-out feature, wherein and as the release button is depressed the cam surface of the frame will make contact with the pin and urge the rotating mass downwardly so pin 72 can travel in opening 74. As a force on the release button is increased, the forces acting on the rotating mass pin will increase to the point sufficient to overcome the friction forces and the ramp angle of the cam surfaces 78 of the frame portion will cause the rotating mass and pin 72 to translate out of the blockout position. This feature is illustrated in
In accordance with an exemplary embodiment, the cam out theory may be explained as follows:
In order to provide cam-out in the event of leaf spring failure the Force of the push button must be greater than the Frictional Force Fpb>Ff.
ΣMa=0=M1−M3
M1>M3
Rpb×L1>Ff×L3
Rpb×L1>0.2×(Rpb)×L3
In the case of spring failure (integral leaf springs), the frame cutout or surface 78 will provide a cam-out when the pushbutton force is sufficient to overcome the opposing friction forces.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/684,877, filed May 26, 2005, the contents of which are incorporated herein by reference thereto.
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