Abstract:
A vehicle seat belt retractor has a frame, a spool rotatably mounted to the frame and a spool locking device for locking the spool against rotation. The spool locking device includes actuating means for actuating the locking device. The actuating means is a support carrying a mass and a pawl, the mass being arranged to move from an initial position to an actuating position to actuate the pawl into engagement with the ratchet on the spool. The actuating means is an adjustment mechanism for adjusting the distance between the pawl and the ratchet. The adjustment mechanism may adjust the support relative to a housing, and adjust the tip of the pawl relative to the pawl body or a deformable pawl tip.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an adjustable vehicle sensor for a retractor of a vehicle seat belt. 
     BACKGROUND OF THE INVENTION 
     A retractor for a vehicle seat belt contains a vehicle sensor, which responds to changes in the vehicle acceleration or deceleration occurring in a vehicle crash. The vehicle sensor is one of two sensor inertial mechanisms within the retractor; the other sensor means detects pay out of the webbing from the retractor due to the movement of a vehicle occupant when the vehicle decreases or increases in speed. The second mechanism is often called a webbing sensor. 
     The vehicle sensor comprises an inertial mass either in the form of a ball or a hollow shaped tube acting on a pin or a mass with a relatively high center of gravity located above a narrow base. Movement of the mass acts on a vehicle sensor lever positioned in close proximity to the mass to move a toothed portion of the vehicle sensor lever into engagement with teeth on a spool or a ratchet thus initiating the locking of the retractor spool and preventing further pay out of the webbing. 
     A typical retractor, including the vehicle sensor, is formed by many cooperating components. One of the problems associated with prior art retractors is that each component can vary in size due to environmental changes such as changes in temperature during the component manufacturing process. For example, components vary in dimensions due to multi cavity tools where more than one component is molded in sequence or at the same time. Also if large volumes of components are manufactured the molding tool may deteriorate or wear causing variation in component sizes. The variation in sizes creates variability in the relationship between each component. This is particularly undesirable in the vehicle sensor as the spacing between the spool teeth and the vehicle sensor locking teeth requires precision. The variation in the gap between the spool or ratchet teeth and the vehicle sensor locking tooth gives poor repeatability of the vehicle sensor&#39;s performance and controls the retractors locking. The space between the spool or ratchet teeth and the vehicle sensor locking tooth is called the “tip gap”. 
     If the gap between the vehicle sensor lever and the spool teeth is too narrow the vehicle sensor lever may engage with the spool teeth and lock the retractor in a non-emergency situation. This can create discomfort for the occupant with the seat belt “jamming”. In the case of an inertial mass in the shape of a ball, the ball rests on a socket and is free to move upon a change in position of the vehicle and retractor. The ball may cooperate directly or indirectly with a vehicle sensor lever. Alternatively the vehicle sensor may contain a cap or lid which sits directly over the inertial mass, which cooperates with the vehicle sensor lever. Upon displacement of the inertial mass the vehicle sensor lever is lifted either via the vehicle sensor inertia cap, directly by the mass or by a system of levers. The vehicle sensor lever is pushed upwards and engages with the teeth on the retractor spool thereby locking the retractor spool and preventing further rotation. 
     If the various retractor components have changed in size, thus creating a varying “tip gap”, and if the vehicle is positioned at an angle the vehicle occupant may not be able to remove the webbing from the retractor rendering the seat belt unusable or creating a very sensitive belt which acknowledges and locks the retractor under non-emergency situations. 
     It is required that all retractors lock within specific pay out of webbing under certain vehicle acceleration and declaration conditions. With wide variations in component sizes the retractor locking times will vary and therefore different amounts of webbing will be released from the retractor. Such variations result in poor performance and efficiency of the seat belt. The higher the variation in the vehicle sensor performance, the higher the likelihood of experiencing high pay out of webbing which will not provide the most effective protection to the vehicle occupant. 
     SUMMARY OF THE INVENTION 
     The present invention is a seat belt retractor vehicle sensor, which can be adjustable in height relative to the position of the retractor spool teeth upon manufacture of the retractor. The present invention provides a seat belt retractor vehicle sensor which can be adjustable in height by repositioning the vehicle sensor housing upon installation of the vehicle sensor on the retractor frame, or by altering the vehicle sensor lever arm to modify the aperture between the spool teeth and the vehicle sensor lever. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation cross section of a seat belt retractor. 
     FIG. 2 is a side elevation cross section of the seat belt retractor of FIG. 1 showing the webbing sensor mechanism and the main locking pawl and multifunction piece. 
     FIG. 3 is a side elevation cross section of the seat belt retractor of FIG. 1 showing the main locking pawl, multifunction piece and the vehicle sensor mechanism. 
     FIG. 4 is a perspective view of the vehicle sensor and one embodiment of the present invention with only part of the spool teeth illustrated. 
     FIG. 5 is a cross sectional view of the vehicle sensor disclosing a further embodiment of the present invention. 
     FIG. 6 is a perspective view, partially broken away, of the vehicle sensor and part of the outer vehicle sensor housing and spool teeth. 
     FIG. 7 is a fragmentary perspective view of the vehicle sensor inner and outer housing without the inertial mass or spool teeth. 
     FIG. 8 is a fragmentary side elevation view of the invention disclosed in FIG.  7 . 
     FIG. 9 Shows a second side view of the embodiment disclosed in FIG.  7 . 
     FIG. 10 is a fragmentary cross sectional view of a vehicle sensor including the inner and outer housings. 
     FIG. 11 is a perspective enlarged view of the embodiment shown in FIG.  10 . 
     FIG. 12 is a cross sectional view of the connection between the vehicle sensor inner and outer housings as disclosed in FIG.  10 . 
     FIG. 13 is a cross sectional view of the connection between the vehicle sensor inner and outer housing after the connection has been made permanent. 
     FIG. 14 is a fragmentary perspective view of a further embodiment of the present invention and the connection between the vehicle sensor inner and outer housing as discussed in FIG. 10 prior to the connection being made permanent. 
     FIG. 15 is a fragmentary cross sectional view of a further embodiment of the present invention with the vehicle sensor inner housing and the spool teeth. 
     FIG. 16 is a fragmentary perspective view of the embodiment disclosed in FIG. 16 with the vehicle sensor inner and outer housings shown and the spool teeth depicted. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1 a seat belt retractor  20  with a ball type vehicle sensor  270  is illustrated. The retractor spool  50  rotates in the frame  30 . The spool  50  is biased in the webbing retraction direction by the retraction spring  70 , which is held in a spring cup  100  and is connected to the spool  50  by a pinion  80 . The spring cup  100  and spring assembly is contained in a spring end cap  90 , that is attached directly to the retractor frame  30 . The spool  50  is used as a storage facility for the webbing (not shown) which is withdrawn from the retractor when the seat belt is placed securely around the vehicle occupant. 
     On the opposite side to the retractor spring sits the retractor locking and sensing devices  200 ,  270 . These include the web sensor mechanism  200 , the main locking pawl (not shown) and the vehicle sensor  270 . The vehicle sensor  270  comprises an inertial ball mass  280  and an inner vehicle sensor housing or subassembly  290  as well as an outer vehicle sensor housing  390 . The inertial mass  280  is held in a socket  281  and is capable of movement. Any change in position of the inertial mass  280  repositions the vehicle sensor cap  330 , which, in turn repositions the vehicle sensor lever. 
     FIG. 2 depicts the web sensor locking device  200  and the main locking pawl  150 . Upon an increase in webbing pay out the spool  50  rotates. If the acceleration of this pay out exceeds between 0.8 g to 2 g the inertial mass  210  cannot rotate with the spool and pushes the web sensor pawl  230  in a clockwise direction around the web sensor pivot pin  260  and locks in the teeth  111  on the multifunction piece  110 . Once the web sensor pawl  230  and the multifunction pieces  110  are locked together the continued rotation of the spool forces the multifunction piece to rotate and moves the main locking pawl  150  into engagement with the spool teeth  190  via the locking pawl pin  160  and the slot or cam surface  170  within the multifunctional piece. 
     FIG. 3 is a cross sectional view of the retractor  20  with the multifunctional piece  110  covering the web sensor mechanism. The connection between the main locking pawl  150  and the multifunctional piece  110  is shown. The locking pawl  150  has a pin  160 , which acts with a slot  170  in the multifunctional piece. Upon locking of the spool (not shown) the multifunctional piece rotates in an anti-clockwise direction rotating the pin  160  through the cam  170  about the locking pawl pivot point  151  thereby engaging the locking pawl  150  with the spool teeth  190 . FIG. 3 also discloses the secondary sensing mechanism  270 , the vehicle sensor. Upon a change in position of the vehicle the inertial mass  280  moves. This movement lifts the secondary vehicle sensor lever  311  around a pivot point  320  and lifts the primary sensor lever  310 , which engages with the spool teeth  190 . This locks the spool and prevents rotation. 
     FIG. 4 is a fragmentary perspective view of the first embodiment of the present invention. The vehicle sensor inertial mass  280  is held within the inner vehicle sensor housing  290  and is contained via the side walls  300 . The vehicle sensor cap  330  rests over the mass and pivots about a hinge point  331 . On normal operation of the retractor the vehicle sensor cap  330  cooperates with the vehicle sensor lever  310  but the lever does not engage the spool teeth  190 , which are free to rotate. The distance between the spool teeth  190  and the vehicle sensor tooth  370  is predetermined by adjusting one leg  360  of the vehicle sensor lever  310  to maneuver the height of the vertically angular vehicle sensor lever leg  340  to the correct position in relation to the spool teeth  190 . 
     The adjustable leg  360  of the vehicle sensor lever  310  can be positioned and secured permanently or temporarily by engaging the end of the leg  360  with the teeth  350  located on the surface of the vehicle sensor lever face closest to the adjustable leg and parallel to the spool teeth  190 . The location of the teeth  350  can be arranged to provide operative spacing between the spool teeth  190  and the vehicle sensor lever locking tooth  370  so that the spacing between the two aforementioned components ensures engagement of the vehicle sensor lever locking tooth and the spool teeth at the most appropriate time and point to guarantee complete engagement and thereby secure locking of the retractor spool. Thus the tip gap is adjusted in relation to the position of the vehicle sensor adjustable leg  360  by engagement with the teeth  350 . 
     The distance between the spool teeth  190  and the vehicle sensor can further be controlled by adjusting the position of the inner vehicle sensor housing  300  in relation to the spool teeth  190 . FIGS. 5 and 6 disclose such a method. The whole inner vehicle sensor housing  300  including the inertial mass  280  and vehicle sensor cap  330  are repositioned on the retractor frame (not shown) upon manufacture of the retractor via serrations  380  on the inner vehicle sensor housing walls  300 . The vehicle sensor inner subassembly  290  can be placed in the outer housing  390  either by deforming the serrations  380  as they are pushed against the outer housing  390  or by using corresponding serration&#39;s on the outer housing allowing more specific positioning of the inner housing. The position of the inner vehicle sensor housing will thus reflect the distance between the spool teeth  190  and the primary vehicle sensor lever  310 . 
     Thus the tip gap is adjusted in relation to the position of the inner vehicle sensor housing  300  to the outer vehicle sensor housing  390 . 
     FIG. 7 discloses a further method of adjusting the distance between the spool teeth and the vehicle sensor locking pawl by positioning the vehicle sensor inner housing  300  on the vehicle sensor outer housing  390 . The inner vehicle sensor housing is manually or automatically positioned in the outer vehicle sensor housing and is secured in the correct position using rivets  400  which are placed through holes in an extending arm  430  connected to the vehicle sensor inner housing  300 . The extending arms  430  surround the outer vehicle sensor housing wall  390 . These outer vehicle sensor housing walls contain slots  420 . The rivets can be secured by various means such as heat treatment or a non-return self-driving helix rivet. 
     FIGS. 8 and 9 show a variation of this embodiment. Serrations  440  on the inner wall of the arm  430  surrounding the outer vehicle sensor housing  390  are pressed against the inner vehicle sensor housing wall  300  when the rivets  400  are pressed through the holes  410  into the slots  420  in the outer vehicle sensor housing wall  390 . The serrations plastically deform the outer vehicle sensor housing  390  thus holding the vehicle sensor inner housing in its correct position. 
     FIGS. 10 and 11 disclose a further embodiment with the inner vehicle sensor housing assembly positioned manually or automatically on the vehicle sensor outer housing via a pin and slot method. The inner vehicle sensor housing  300  has two extending pieces on either side of the housing either directly parallel to each other or adjacent. Both sides of the housing  300  contain a vertical slot  460  through which the pin  470  from the outer vehicle sensor housing extends. Surrounding the slots are serrations  440  as shown in FIG.  11 . Upon positioning the inner vehicle sensor housing via the slots and the outer vehicle sensor housing pins  470  the manufacturing operator will be able to adjust the position of the inner housing vertically until the vehicle sensor lever is positioned at the correct distance from the spool teeth (not shown. Once the correct position is located (as in FIG. 12) the pins  470  on the outer vehicle sensor housing are deformed by, for example, heat treatment, pressure being applied to the pins or an ultrasonic method, forcing the pin head  471  to crush and press against the serrations  440  surrounding the slot  460 . This secures the inner vehicle sensor housing to the outer vehicle sensor housing. FIG. 13 shows the pin deforming via a deforming element such as a heat gun or simply by pressure exerted onto the head of the pin. The deformed pin head  471  is pressed into the serrations  440  deforming the serrations and securing the pin head to the inner vehicle sensor housing  300 . 
     FIG. 14 shows variations of this embodiment. there could be a number of pins  470  to provide a more secure method of connection and the pins  470  could be molded with a head which was deformed in some manner prior to securing the connection thus allowing less force to be required upon the pin head  471  when deforming to secured the connection permanently. 
     FIGS. 15 and 16 disclose a method of continually allowing the vehicle sensor lever tooth to engage with the spool teeth without adjusting the vehicle sensor housing or vehicle sensor lever&#39;s position. The vehicle sensor lever  310  pivots about a pivot hinge point  320  that is connected to the inner vehicle sensor housing  290 . The vehicle sensor lever  310  is not rigid and can flex to a certain angle upon engagement with the spool teeth  190 . As the vehicle sensor lever  310  is elastically bendable it is capable of engaging with the spool teeth  190  when required. The inner vehicle sensor housing is static thus allowing the vehicle sensor to swing into position around the pivot point  320  upon movement of the inertial mass  280 . Thus the tip gap is automatically adjustable as the vehicle sensor lever  310  flexes to engage the vehicle sensor locking tooth  370  with the spool teeth  190  at the correct point on the spool teeth. 
     It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces such modified forms thereof as come within the scope of the following claims.