Abstract:
A helmet adjustment mechanism is adapted to adjust the size of a helmet having first and second retention members (e.g., plastic straps) movable with respect to each other. The adjustment mechanism includes an actuating member (e.g., a pinion) coupled to at least one of the retention members and movable (e.g., rotatable) in two directions to move at least one of the retention members relative to the other. A clutch mechanism is coupled to the actuating member and includes at least one locking member (e.g., two locking members) that inhibits movement of the actuating member in both of the two directions. The adjustment mechanism also includes a release mechanism (e.g., including a rotary dial) adapted to move the locking member from a locked position to an unlocked position to allow movement of the actuating member. When the actuating member is being moved, the adjustment mechanism also provides a ratcheting detent.

Description:
BACKGROUND 
       [0001]    The present invention generally relates to the field of bicycle helmets, and specifically to mechanisms for adjusting the size of bicycle helmets. 
         [0002]    Bicycle helmets have progressed to be highly-engineered pieces of equipment. One important aspect of a bicycle helmet design is that it fit comfortably and securely on a user&#39;s head. One way of making a helmet comfortable and secure is to provide an adjustable harness that is secured inside the helmet shell and wraps around a user&#39;s head. 
       SUMMARY 
       [0003]    The present invention provides a helmet adjustment mechanism that is adapted to adjust the relative position of two parts of the helmet. The adjustment mechanism is particularly suited for bicycle helmets having a shell adapted to fit on a user&#39;s head, and first and second retention members (e.g., plastic straps having toothed slots) coupled to the shell and movable with respect to each other to adjust a size of the helmet. The adjustment mechanism is coupled to the retention members and includes an actuating member (e.g., a pinion) coupled to at least one of the retention members and movable (e.g., rotatable) in two directions to move at least one of the retention members relative to the other. The adjustment mechanism further includes a clutch mechanism coupled to the actuating member and including at least one locking member (e.g., two locking members) that inhibits movement of the actuating member in both of the two directions. The locking member is movable between a locked position, where the actuating member is substantially prevented from moving, and an unlocked position, where the actuating member is not substantially prevented from moving. The adjustment mechanism also includes a release mechanism (e.g., including a rotary dial) adapted to move the locking member from the locked position to the unlocked position to allow movement of the actuating member. When the actuating member is being moved, the adjustment mechanism also provides a ratcheting detent. 
         [0004]    In one embodiment, the clutch mechanism includes a first locking member that inhibits movement of the actuating member in a first direction (e.g., counter-clockwise) and a second locking member that inhibits movement of the actuating member in a second direction (e.g., clockwise). Each of the first and second locking members is preferably movable between a locked position, where the actuating member is substantially prevented from moving in the respective direction, and an unlocked position, where the actuating member is not substantially prevented from moving in the respective direction. In this embodiment, the release mechanism is adapted to move the first locking member from the locked position to the unlocked position while simultaneously leaving the second locking member in the locked position to thereby allow the actuating member to move in the first direction. When the actuating member is being moved in the first direction, the second locking member can provide the ratcheting detent, but still retains its locking feature to prevent movement in the second direction. 
         [0005]    In order to provide the locking feature, the clutch mechanism can include a series of clutch teeth for releasable engagement by the locking members. Preferably, the locking members each include a flexible arm having a latch portion (e.g., a latch tooth) for engaging the clutch teeth, and a first cam portion. In this embodiment, the adjustment mechanism can further include an input member (e.g., a rotary dial) movable by a user and including a second cam portion adapted to engage the first cam portion to move the locking member from the locked position to the unlocked position. 
         [0006]    In one embodiment, the input member is movable relative to the clutch member between a static position and an adjusting position. In this embodiment, the locking member is in the locked position when the input member is in the static position, and movement of the input member to the adjusting position automatically moves the locking member to the unlocked position. Preferably, the input member further includes a drive portion adapted to drive the actuating member (e.g., tabs on the clutch member) when the input member is in the adjusting position. 
         [0007]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a bicycle helmet having an adjustment mechanism embodying features of the present invention. 
           [0009]      FIG. 2  is an exploded perspective view of the adjustment mechanism of  FIG. 1 . 
           [0010]      FIG. 3  is a front perspective view of a clutch member. 
           [0011]      FIG. 4  is a rear perspective view of the clutch member. 
           [0012]      FIG. 5  is a rear perspective view of a dial. 
           [0013]      FIG. 6  is a front view of the adjustment mechanism in partial section with the adjustment mechanism in a neutral position. 
           [0014]      FIG. 7  is the front view of  FIG. 6  with the adjustment mechanism in a tightening position. 
           [0015]      FIG. 8  is the front view of  FIG. 6  with the adjustment mechanism in a loosening position. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
         [0017]    The helmet  10  in  FIG. 1  includes a shell  12  that provides protection to the user&#39;s head. The shell  12  includes a concave interior dimensioned to fit over a user&#39;s head, and a series of openings  14  to provide ventilation to the user. The shell  12  can be made from any suitable protective material, such as an impact-absorbing layer  16  made from closed cell polystyrene foam adhered to a molded outer skin  18  made from polycarbonate plastic. 
         [0018]    The helmet  10  further comprises a retention mechanism in the form of a harness  20  including several stabilizers (not shown) secured to the shell  12  (e.g., molded into the shell  12  or attached by mechanical, adhesive, or other means), as is known in the art. The harness  20  further includes a strap portion  24  designed to encompass a user&#39;s head. The strap portion  24  includes two ends that define first and second straps  26 , 28  that facilitate adjusting the size of the strap portion to accommodate different-sized heads. The harness  20  can be made from any suitable material, such as plastic, wire, woven fabric, and the like. 
         [0019]    Referring to  FIG. 2 , each strap  26 , 28  includes an opening in the form of a slot  30 . The first strap  26  includes lower teeth  32  defining a lower perimeter of the corresponding slot  30 , and the second strap  28  includes upper teeth  34  defining an upper perimeter of the corresponding slot  30 . The two straps  26 , 28  overlap each other such that the slot  30  of the first strap  26  at least partially overlaps the slot  30  of the second strap  28 . In an alternative embodiment (not shown), instead of have a slot with teeth, the strap could instead be a very thin, elongated member with teeth along one side of the strap, similar to a toothed rack. 
         [0020]    The helmet  10  further includes an adjustment mechanism  38  for adjusting the straps  26 , 28  to fit the user&#39;s head size. The adjustment mechanism  38  includes a base member  40  designed to cover the occipital region of the user&#39;s head. The base member  40  is butterfly-shaped, and includes opposing bridge portions  42  through which the straps  26 , 28  are threaded. A base post  44  is positioned in a center region of the base member  40  such that it is positioned in the slots  30  of the straps  26 , 28  when the straps  26 , 28  are threaded through the bridge portions  42 . Alignment walls  46  extend from the central region of the base member  40  on opposing sides of the base post  44  and are positioned to maintain the straps  26 , 28  in an overlapping relationship. 
         [0021]    The adjustment mechanism  38  further includes an actuating member in the form of a pinion  50  rotationally mounted on the base post  44 . Referring to  FIGS. 3 ,  4  and  6 , the pinion  50  includes a series of circumferentially-arranged teeth  52  engaging both the upper teeth  34  of the second strap  28  and the lower teeth  32  of the first strap  26 . As a result of this arrangement, rotation of the pinion  50  results in movement of the first and second strap  28  relative to the base member  40 . More specifically, when viewed from the front of the helmet  10  ( FIG. 6 ), counter-clockwise rotation of the pinion  50  results in tightening of the straps  26 , 28  (i.e., moving the straps  26 , 28  toward each other and adjusting the helmet  10  to a smaller size), and clockwise rotation results in loosening of the straps  26 , 28  (i.e., moving the straps  26 , 28  away from each other and adjusting the helmet  10  to a larger size). 
         [0022]    The adjustment mechanism  38  further includes a clutch mechanism that retains the pinion  50  in the desired position until an adjustment is desired. Referring to  FIGS. 3 and 4 , the clutch mechanism includes a clutch base  60  secured to the pinion  50 , drive tabs  62  extending from the clutch base  60 , locking members in the form of flexible arms  64  extending from the clutch base  60 , and a disk portion  66  between the clutch base  60  and the pinion  50 . The clutch base  60 , drive tabs  62 , flexible arms  64 , disk portion  66 , and pinion  50  are all integrally formed as a single part called the clutch member  65 . The clutch member  65  includes a cylindrical bore  67  adapted to rotationally receive the base post  44 . As a result of the integral nature of the illustrated clutch member  65 , rotation of the drive tabs  62  about the base post  44  will result in rotation of the pinion  50  about the base post  44 , as described below in more detail. 
         [0023]    Each flexible arm  64  extends from the clutch base  60  in a cantilever-like fashion such that a free end of each flexible arm  64  is able to resiliently flex and move relative to the clutch base  60 . The end of each flexible arm  64  includes a latch tooth (i.e., a first latch tooth  68  and a second latch tooth  70 ) and a first cam portion including a ramped surface  72 , the function of which will be described below in more detail. Due to its inherent flexible and resilient characteristics, when flexed radially-inwardly, each flexible arm  64  provides a radially-outward bias to the corresponding latch tooth  68 , 70 . 
         [0024]    Referring to  FIG. 2 , the adjustment mechanism  38  further includes a cover member  82  that is adapted to be secured to the base member  40  at the bridge portions  42  by any suitable mechanism, such as a mechanical fastener or adhesive. The cover member  82  includes a cover post  84  extending toward and in alignment with the base post  44  of the base member  40 . When the cover member  82  is secured to the base member  40 , the cover post  84  is positioned inside the bore  67  to rotationally support the clutch member  65  and essentially acts as an extension of the base post  44 . 
         [0025]    The cover member  82  includes a cylindrically-shaped recess  86  defined by a series of radially-inwardly facing cover teeth  88 . When the adjustment mechanism  38  is assembled, the latch tooth  68 , 70  of each flexible arm  64  engages the cover teeth  88  in such a manner as to prevent rotation of the clutch member  65  relative to the base member  40  and cover member  82 . More specifically, when viewed from the front of the helmet ( FIG. 6 ) the first latch tooth  68  substantially prevents counter-clockwise rotation of the clutch member  65  due to its engagement with the cover teeth  88 , and the second latch tooth  70  substantially prevents clockwise rotation of the clutch member  65  due to its engagement with the cover teeth  88 . Due to the shape of the first latch tooth  68  and its ability to move radially inwardly by flexing the corresponding flexible arm  64 , the first latch tooth  68  does not prevent rotation of the clutch member  65  in the clockwise direction. Rather, when the clutch member  65  is rotated in the clockwise direction, the first latch tooth  68  will cam off of the cover teeth  88  to act as a ratcheting detent. Similarly, the second latch tooth  70  acts as a ratcheting detent when the clutch member  65  is rotated in the counter-clockwise direction. 
         [0026]    The adjustment mechanism  38  further includes a release mechanism that facilitates rotation of the clutch member  65  and pinion  50 . Referring to  FIGS. 2 and 5 , the release mechanism includes an input member in the form of a dial  90  that is sandwiched between the base member  40  and the cover member  82 . The dial  90  is disk-shaped and includes a coined outer edge  92  to facilitate gripping by a user&#39;s fingers in order to rotate the dial  90 . The dial  90  further includes a central, disk-shaped hole  94  dimensioned to receive the disk portion  66  of the clutch base  60  such that the dial  90  can rotate relative to the disk portion  66 . The dial  90  further includes a cylindrical recess  96  dimensioned to receive the flexible arms  64  of the clutch member  65 . 
         [0027]    The dial  90  further includes second cam portions in the form of semi-cylindrical bumps  98  extending radially inward from the surface defining the cylindrical recess  96 . As shown in  FIG. 6 , the bumps  98  are positioned adjacent to and are circumferentially aligned with the ramped surfaces  72  of the flexible arms  64 . As a result of this orientation, rotation of the dial  90  relative to the clutch member  65  will cause one of the bumps  98  to cam against a corresponding ramped surface  72  to thereby cause radially-inward deflection of the corresponding flexible arm  64 . This deflection of the flexible arm  64  will result in the disengagement of the corresponding latch tooth  68 , 70  from the cover teeth  88 , which will allow the clutch member  65  and pinion  50  to be rotated in the same direction that the dial  90 . 
         [0028]    The dial  90  further includes opposing wedge-shaped recesses  100  that are defined by drive surfaces  102  on either end. Each wedge-shaped recess  100  is dimensioned to loosely receive one of the drive tabs  62  of the clutch member  65 . In the neutral position ( FIG. 6 ), each drive tab  62  will be approximately centrally positioned within the corresponding wedge-shaped recess  100 . As a result of this configuration, the dial  90  can be rotated slightly in each direction without the drive surfaces  102  engaging the corresponding drive tab  62 . After a certain amount of rotation of the dial  90  (e.g. 35 degrees), the drive surfaces  102  will engage the corresponding tab  62 . 
         [0029]    In operation, the size of the helmet  10  can be adjusted by rotating the dial  90 . When in the neutral or static position (i.e., with no user input to the dial  90 ), the bumps  98  on the dial  90  are adjacent to but not pressing against the ramped surfaces  72  ( FIG. 6 ). As a result, the latch teeth  68 , 70  are in engagement with the cover teeth  88 , and the clutch member  65  and pinion  50  are substantially prevented from rotating. 
         [0030]    When it is desired to tighten the helmet  10  (i.e., make the helmet  10  smaller), the dial  90  is rotated counter-clockwise ( FIG. 7 ) by the user. Counter-clockwise rotation of the dial  90  causes one of the bumps  98  to engage the corresponding ramped surface  72 , and causes disengagement of the first latch tooth  68  from the cover teeth  88 . Further rotation of the dial  90  in the counter-clockwise direction results in the drive surfaces  102  of the dial  90  engaging the tabs  62  on the clutch member  65 . Continued counter-clockwise rotation of the dial  90  results in counter-clockwise rotation of the clutch member  65  and pinion  50 , which causes tightening of the straps  26 , 28 . During this tightening rotation, the second latch tooth  70  ratchets off of the cover teeth  88  to act as a detent. When the desired size of the helmet  10  is achieved, the user releases the dial  90 , and the dial  90  will return to the neutral position due to the biasing forced provided by the flexible arm  64  through its ramped surface  72  and on the bump  98 . As the dial  90  returns to its neutral position, the first latch tooth  68  reengages with the cover teeth  88 . 
         [0031]    Loosening of the helmet  10  (i.e., making the helmet  10  larger) is accomplished by rotating the dial  90  in the clockwise direction, as will be apparent to one skilled in the art. This operation is generally illustrated in  FIG. 8 .