Patent Publication Number: US-8979129-B2

Title: Seat belt retractor

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/478,329, filed on Apr. 22, 2011. U.S. Provisional Patent Application No. 61/478,329 is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     The present application relates generally to the field of seat belt retractors for use in seat belt systems for restraining secured occupants of a vehicle. More specifically, the present application relates to an apparatus for reducing the noise generated by a seat belt retractor. 
     SUMMARY 
     One embodiment relates to a retractor for a seat belt system of a vehicle. The retractor includes a rotatable spool configured to be connected to a webbing wherein the webbing moves in an extraction direction and a retraction direction upon rotation of the spool, a locking member configured to selectively lock the spool and prevent the spool from rotating in the webbing extraction direction, a sensor, and a cover for the sensor and locking member. The locking member is configured to move between a free position and a locked position relative to the spool. When the locking member is in the locked position, the spool is prohibited from rotating in the webbing extraction direction. When the locking member is in the free position, the spool is freely rotatable. The sensor is configured to move in a first direction in response to the vehicle having a threshold acceleration and wherein movement of the sensor in the first direction causes a corresponding movement of the locking member from the free position to the locked position. The sensor is located in a cavity in the cover and an insert member is disposed between the cover and the sensor to limit the travel of the sensor in a second direction that is transverse to the first direction. 
     Another embodiment relates to a seat belt system for a vehicle for restraining a secured occupant. The seat belt system includes a webbing having a first end and a second end, an anchor configured to secure the first end of the webbing, a tongue member slideably coupled to the webbing and configured to selectively engage a buckle mechanism, and a retractor. The retractor includes a rotatable spool configured to be connected to the second end of the webbing wherein the webbing moves in an extraction direction and a retraction direction upon rotation of the spool, a locking member configured to selectively lock the spool and prevent the spool from rotating in the webbing extraction direction, a sensor, and a cover for the sensor and locking member. The locking member is configured to move between a free position and a locked position relative to the spool. When the locking member is in the locked position, the spool is prohibited from rotating in the webbing extraction direction. When the locking member is in the free position, the spool is freely rotatable. The sensor is configured to move in a first direction in response to the vehicle having a threshold acceleration and wherein movement of the sensor in the first direction causes a corresponding movement of the locking member from the free position to the locked position. The sensor is located in a cavity in the cover and an insert member is disposed between the cover and the sensor to limit the travel of the sensor in a second direction that is transverse to the first direction. 
     Yet another embodiment relates to a retractor for a seat belt system of a vehicle. The retractor includes a rotatable spool configured to be connected to a webbing wherein the webbing moves in an extraction direction and a retraction direction upon rotation of the spool, a locking member configured to selectively lock the spool and prevent the spool from rotating in the webbing extraction direction, a sensor, and a cover defining a cavity for housing the sensor. The locking member is configured to move between a free position and a locked position relative to the spool. When the locking member is in the locked position, the spool is prohibited from rotating in the webbing extraction direction. When the locking member is in the free position, the spool is freely rotatable. The sensor is configured to move in a first direction in response to the vehicle having a threshold acceleration and wherein movement of the sensor in the first direction causes a corresponding movement of the locking member from the free position to the locked position. The cover includes an outer layer of structural material and an inner layer of elastomeric material formed over the outer layer to dampen a noise of contact between the sensor and the cover. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
         FIG. 1  is a schematic side view of a vehicle interior showing a seat belt assembly, according to an exemplary embodiment. 
         FIG. 2  is a side view of a portion of the cover for the retractor of  FIG. 1  with a sound dampening feature. 
         FIG. 3  is a side view of a portion of the retractor of  FIG. 1 , according to an exemplary embodiment. 
         FIG. 4  is a side view of a portion of the retractor of  FIG. 1  with a sensor mechanism removed to show a sound dampening feature, according to an exemplary embodiment. 
         FIG. 5  is a cross-sectional view taken through the portion of the retractor of  FIG. 4 . 
         FIG. 6  is another cross-sectional view of another exemplary embodiment of a retractor. 
     
    
    
     DETAILED DESCRIPTION 
     With general reference to the Figures, disclosed herein are retractors for use in seat belt systems configured to include a sensing mechanism for detecting a vehicle acceleration to selectively lock a webbing from being extracted from the retractor. The sensing mechanism may be configured for use as a vehicle sensor (VS) having a sensor configured to detect a change in the inertia of the vehicle, whereby the sensor may activate a locking member (e.g., an actuator), which is configured to selectively lock the retractor, such as a gear of a spool of the retractor, when the sensor detects a threshold inertia, such as a threshold vehicle acceleration, which may be caused by a sudden stop in the vehicle or a high g-force turn through a sharp curve at relatively high speed. The term acceleration as used herein refers to the absolute value of the acceleration that the vehicle experiences, whether negative (e.g., deceleration) or positive. The sensing mechanism also includes a member (e.g., insert member) that is configured to reduce the noise of the retractor without impeding the performance of the locking of the retractor upon the threshold vehicle acceleration. 
       FIG. 1  illustrates an exemplary embodiment of a seat belt system  10  for use in a vehicle  2  to help restrain the movement of an occupant  11  during a sudden acceleration, typically resulting from a dynamic impact event of the vehicle. The seat belt system  10  includes a webbing or belt  12 , a buckle  14 , a tongue member  16  slideably coupled to the webbing  12  and configured to selectively engage the buckle  14 , an anchor member  18  configured to secure an end of the webbing  12 , and a retractor  20 . During normal vehicle use (i.e., when the vehicle does not experience a threshold acceleration), the retractor  20  may allow the webbing to be freely extracted and retracted from the retractor  20 . During a dynamic impact event of the vehicle (i.e., resulting in a threshold vehicle acceleration), the retractor  20  is configured to lock the webbing  12  to prohibit extraction or unwinding to thereby restrict the movement of the occupant. 
     U.S. Patent Application Publication Number 2008/0203808 discloses seat belt systems configured to restrain secured occupants. The seat belt systems include a retractor having a spool configured to wind and unwind a seat belt webbing. The retractors may also include a planetary gear train for transmitting rotation of the spool to an operation member. U.S. Patent Application Publication Number 2008/0203808 is hereby incorporated by reference in its entirety. As explained and taught further below, retractors of the seat belt systems (e.g., the retractors of those seat belt systems disclosed in U.S. Patent Application Publication Number 2008/0203808) may be configured to include a sensing mechanism having a sensor configured to activate a locking member and a member (e.g., insert member) configured to reduce the noise of the retractor without impeding the performance of the locking of the retractor upon the threshold vehicle acceleration. 
     As shown, the seatbelt webbing  12  is connected to the retractor  20 . For example, the retractor  20  may include a spool  23  that the webbing  12  is coupled to, such that upon rotation of the spool  23 , the webbing  12  is extracted from or retracted into the retractor  20 . The retractor  20  may also include a biasing member (not shown) that imparts a biasing force onto the spool  23  to retract the webbing  12 . Thus, the retractor  20  may function to maintain the seatbelt webbing  12  in a loaded state (i.e., state of tension), but allows for additional seatbelt webbing  12  to be released or extracted, such as when an occupant enters a vehicle and puts on the seatbelt webbing  12 . In addition to the spool and the biasing member, the retractor  20  may include various other mechanisms such as, for example, a locking mechanism, a pretensioner, and one or more sensing mechanisms having one or more sensors. 
     The sensing mechanism may include at least one sensor configured to detect a sudden change in the inertia of the vehicle, such as a vehicle acceleration. Each sensor may be configured to send a signal to a controller (not shown) for the retractor  20  to activate the retractor  20  as appropriate depending on whether the sensor detects a low or high acceleration event. In other words, the sensor may be configured to react to a threshold change in vehicle inertia or vehicle acceleration to change the retractor  20  from operating in a first free mode of operation, such as where the webbing  12  is allowed to be freely extracted from the retractor  20 , to a second locked mode of operation, such as where the webbing  12  is prohibited from being extracted from the retractor  20 . 
     As shown in  FIG. 3 , the sensing mechanism  21  is configured as a VS including a cover  24  (e.g., casing) which may be fixed to a housing  26  (e.g., a frame) of retractor (e.g., retractor  20 ), a sensor  22  disposed in the cover  24 , and a locking member  25  (e.g., pawl). The sensor  22  may be configured to detect and react to a threshold change in the inertia of the vehicle, such as induced by a sudden change in the level of acceleration by the vehicle, whereby the sensor  22  may move and in turn move the locking member  25  a corresponding distance, such as to move the locking member  25  from a free position to a locked position relative to the spool  23 . When in the free position, the locking member  25  may be separated from (e.g., disengaged from) the spool  23 , such that the spool  23  may freely rotate in both the webbing extraction and retraction directions. When in the locked position, the locking member  25  engages the spool  23 , such that the spool  23  may not rotate in at least the webbing extraction direction. In other words, the spool  23  of the retractor  20  may be allowed to rotate in only the webbing retraction direction when the locking member  25  is in the locked position, such as to allow the webbing  12  to be undergo a pretensioning by a pretensioner, but to prohibit extraction of the webbing  12  from the retractor  20  to thereby limit the travel or movement of the occupant. Accordingly, the locking member  25  may engage a gear  23   b  of the spool  23  through a ratcheting arrangement to allow rotation in only a single direction, when the locking member  25  is in the locked position. 
     The sensor  22  may be configured as an inertial sensor, which may be configured to move when subjected to a change in inertia of the vehicle, such as an inertia induced by a sudden vehicle acceleration that exceeds the threshold acceleration. The inertial sensor  22  may move to a position that activates the locking member  25 , whereby the locking member  25  moves from the free position to the locked position. For example, the inertial sensor may be configured as a substantially spherical ball-type sensor. As another example, the inertial sensor may be configured as a standing man sensor having an irregular shaped mass that may rest on a member having a fulcrum in which the standing man sensor may tilt about during changes in vehicle inertia. The tilting of the standing man sensor drives actuation of the locking member to lock the retractor to prohibit the extraction of the webbing from the retractor. 
     Since these types of retractors rely on the movement of the sensor to provide sensing of the vehicle acceleration, a clearance generally exists between the sensing mechanism and one or more of the interior components of the retractor  20 . For example, there may be a clearance provided between the sensor  22  of the sensing mechanism  21  and the cover  24  and/or the housing  26  of the retractor  20 , such as to allow movement of the sensor  22  relative to the cover  24  and/or the housing  26 . During operation of the retractor  20  and/or operation of the vehicle, the vehicle generally induces vibrations or oscillations that lead to noise (e.g., buzzing, rattling, etc.) being generated by the interior components of the retractor  20  contacting the housing of the retractor  20 . Such noise may be objectionable to occupants of the vehicle. 
       FIGS. 2-6  illustrate exemplary embodiments of an insert  30  that is provided in the sensing mechanism  21  to reduce the noise level, such as to eliminate or greatly reduce the likelihood of objectionable noise from the retractor sensing mechanism  21 . The insert  30  may be configured to dampen the noise generated by the interior components of the retractor  20  having clearances therebetween. For example, the insert  30  may be configured to dampen the noise generated by the sensor  22  contacting the cover  24  caused by vehicle vibrations. 
     According to an exemplary embodiment, the insert  30  is integrally formed with the cover  24 . According to another exemplary embodiment, the insert  30  is integrally formed with the housing  26  of the retractor  20 . For these embodiments, the insert  30  may be a second layer of a material that is formed on a first layer of a material of the cover  24  (or housing  26 ). For example, the cover  24  may be made out of a polypropylene (or any suitable material) formed during a first process, such as an injection molding process. Then, the cover  24  may have a second layer of insert material formed over the first layer of the polypropylene. For example, the second layer may be made from neoprene (or any suitable material, such as an elastomer). Thus, the second neoprene layer of the insert  30  may dampen the noise relative to the first polypropylene layer and the first layer may provide structure (e.g., strength) to the retractor  20 . The first layer of material may be formed with vent holes to facilitate bonding or adhesion of the second layer when formed to the first layer. 
     Accordingly, the insert  30  may be disposed between an interior component, such as a sensor  22  of the sensing mechanism  21  and the cover  24  and/or the housing  26  of the retractor  20 . The insert  30  may be provided in the cavity formed by the cover  24  and/or the housing  26 . As shown in  FIG. 5 , the insert  30  may be spaced apart from a side wall  24   a  of the cover  24 , such as to allow the insert  30  to deflect toward the side wall  24   a . As shown in  FIG. 6 , the insert  30  may be spaced apart from a side wall  26   a  of the housing  26  of the retractor  20 . It should be noted that the spaced apart distance between the insert  30  and the adjacent side wall may be different and may be tailored to the specific retractor. For example, the spacing distance may be driven by an amount of deflection that the insert  30  may undergo during operation of the retractor and/or vehicle. 
     According to an exemplary embodiment, the insert  30  is a separate component such as a sheet of a resilient material (e.g., rubber, a thermoplastic elastomer, etc.) that is configured to dampen the undesirable movement of the moving components. For example, the insert  30  may be made from neoprene and inserted into and retained by the cover  24 . By being resilient, the insert  30  may advantageously be able to flex, such as when contacted by the sensor to reduce the likelihood of noise being generated, but not to impede performance of the sensor. The insert  30  may have a thickness that is large enough to provide sufficient dampening but thin enough to not interfere with the normal operation of the interior components of the retractor  20 , such as to impede or retard the movement of the sensor  22  in the direction(s) to activate/deactivate the locking member  25 . According to one exemplary embodiment, the insert  30  has a thickness of approximately 1 mm. For example, the insert  30  may be between 0.5 mm and 1.5 mm thick. 
     In one exemplary embodiment, the insert  30  may be held in place by the compression force between the interior components of the retractor  20  (e.g., a sensing mechanism  21 ) and the cover  24  and/or the housing  26 . For example, the insert  30  may be compressed between the sensor  22  and the side wall (e.g., a portion of the cover  24 , a portion of the housing  26 ). The compression between the sensor  22  and side wall may impart a force (e.g., a biasing force) into the sensor  22 , where the force is in a first direction that is transverse to a second direction corresponding to the direction of movement of the sensor  22  when activating/deactivating the locking member  25  (i.e., to selectively lock the retractor  20  to prohibit extraction of the webbing  12 ). 
     In another exemplary embodiment, the insert  30  may be offset a distance from the sensor  22 , where the insert  30  limits the travel of the retractor  20  in the direction transverse to the direction of movement of the sensor  22  when activating/deactivating the locking member  25 . This arrangement reduces the noise by reducing the lateral movement of the sensor  22 , while not impeding the performance (e.g., movement) of the sensor  22  when activating/deactivating the locking member  25 . 
     In another exemplary embodiment, the insert  30  may have coupling features (e.g., bosses, barbs, snaps, etc.) that engage corresponding features on the interior component, the cover  24 , or the housing  26 . For example, the cover  24  may include channels that are configured to receive ends of the insert  30  to retain the insert  30  in place. As another example, the insert  30  may include an adhesive (e.g., an adhesive backing) that is configured to couple at least a portion of the insert  30  to a mating portion of another component of the retractor  20 , such as to one or more extensions of the cover  24 . In still another exemplary embodiment, the insert  30  may be integrally formed with a component of the retractor, such as with a two-shot injection molding process. The insert  30  may cover a relatively large area of the cover  24  or housing  26  or may be localized to only an area where interior components contact the cover  24  or housing  26 , such as in the area local to the sensor. 
     The present disclosure has been described with reference to example embodiments, however persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the disclosed subject matter. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments. Because the technology of the present disclosure is relatively complex, not all changes in the technology are foreseeable. The present disclosure described with reference to the exemplary embodiments is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the exemplary embodiments reciting a single particular element also encompass a plurality of such particular elements. 
     As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     It is important to note that the construction and arrangement of the seat belt retractors as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.