Abstract:
A locking mechanism for a headgear suspension using two racks, a pinion, a driver and a lockable knob. The two racks are positioned on the suspension such that they overlap and permit engagement of the gears on the driver with teeth on the rack such that when the lockable knob is in the unlocked position the driver tightens or loosens the racks to adjust the diameter of the suspension to the user&#39;s head size. The lockable knob of the invention operates on a pull, rotate, push and lock system. There are no metal parts and the lockable knob can be locked and unlocked with one hand, by the user.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relaxes to safety headgear such as helmets and visors with adjustable lockable suspensions and specifically to a mechanism for adjusting the size of the suspension to fit a user&#39;s head and a locking mechanism to easily and readily secure the fit. 
       BACKGROUND OF THE INVENTION 
       [0002]    Helmets or visors with suspension systems to secure a helmet or visor to a user are used in a number of industries as protective headgear for workers and drivers of vehicles such as motorcycles and snowmobiles. 
         [0003]    Suspension systems and mechanisms for adjusting and mechanisms for locking them are known in the art. Examples include those disclosed in U.S. Pat. No. 4,942,628 issued on Jul. 24, 1990 in the name of Freund. Another example is US Patent Application 2004/0060154 published Apr. 1, 2004 in the name of Landrey. 
       SUMMARY OF THE INVENTION 
       [0004]    In accordance with an aspect of the present invention there is provided a lockable knob, comprising:
       a support;   a knob rotatably mounted on said support;   one of said knob and said support having a radially directed protuberance and another of said knob and said support having a resilient portion which is resiliently deflected over said protuberance when said knob is axially displaced from a first axial position whereat said resilient portion is on one side of said protuberance to a second axial position whereat said resilient portion is on an opposite side of said protuberance;   said support having a locking feature;   said knob having a complementary locking feature for locking to said support locking feature when said knob is in said first axial position, whereby said knob is rotatable only when in said second axial position.       
 
         [0010]    In accordance with a further aspect of the present invention there is provided a suspension system for a helmet, comprising:
       a housing;   a suspension having a rack at either end overlapping within said housing;   a pinion extending within said housing and meshing with each said rack;   a driver rotatably supported on said housing and telescopingly receiving a drive end of said pinion;   one of said housing and said driver having a radially directed protuberance and another of said driver and said housing having a resilient portion which is resiliently deflected over said protuberance when said driver is axially displaced from a first axial position whereat said resilient portion is on one side of said protuberance to a second axial position whereat said resilient portion is on an opposite side of said protuberance;   said housing having a locking feature;   said driver having a complementary locking feature for locking to said housing locking feature when said driver is in said first axial position.       
 
         [0018]    In one embodiment of the present invention, there is provided a suspension system wherein said radially directed protuberance comprises a lip circumferentially extending about an annulus of said housing. 
         [0019]    In another embodiment of the present invention, there is provided a suspension system wherein said resilient portion comprises a resilient leg depending from said driver having a radially inwardly directed foot. 
         [0020]    In accordance with a further aspect of the present invention there is provided a method for adjusting and locking a headgear suspension, the method comprising the steps of unlocking said suspension by pulling a knob of the present invention to deflect said resilient portion over said protuberance to axially displace said knob from a first axial position on one side of said protuberance to a second axial position whereat said resilient portion is on an opposite side of said protrusion permitting free rotation of said resilient portion in said second axial position but not in said first axial position. 
         [0021]    In accordance with a further aspect of the present invention there is provided a method for adjusting and locking a headgear suspension, the method comprising the steps of unlocking said suspension by pulling a lockable knob of the present invention to deflect the resilient portion over the protuberance to axially displace the knob from a first axial position on one side of the protuberance to a second axial position whereat the resilient portion is on an opposite side of the protrusion permitting free rotation of the resilient portion in the second axial position but not in the first axial position. 
         [0022]    These and other features, aspects and advantages of the invention will become evident to those skilled in the art from a reading of the present description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a photograph of one embodiment of a bottom plan view of a knob or cap portion of the locking mechanism of the invention; 
           [0024]      FIG. 2  is a photograph of these parts of an embodiment of the invention showing in  FIG. 2A  a top perspective view of a knob or cap portion of the locking mechanism of the invention, and in  FIG. 2B  top perspectives views of a support and a housing for mounting the support, for the locking mechanism of the invention; 
           [0025]      FIG. 3  illustrates photographs of four parts of the invention with a bottom perspective view of a knob or cap portion of the locking mechanism of the invention; 
           [0026]      FIG. 3B  is a photograph illustrating a top perspective view of an embodiment of a support for the locking mechanism of the invention; 
           [0027]      FIG. 3C  is a photograph illustrating a top perspective view of an embodiment of a driver for the locking mechanism of the invention; 
           [0028]      FIG. 3D  is a photograph illustrating a top perspective view of an embodiment of a housing for the locking mechanism of the invention; 
           [0029]      FIG. 4  is a first embodiment in assembled perspective view illustrating an embodiment of a locking mechanism of the invention, in a locked position, attached to a headgear suspension; 
           [0030]      FIG. 5  is an exploded view of a locking mechanism, two racks and partial headgear suspension of an embodiment of the invention; 
           [0031]      FIG. 6  is another exploded view of a locking mechanism, 2 racks and partial headgear suspension of an embodiment of the invention; 
           [0032]      FIG. 7  is a diagrammatical view of an embodiment of the invention illustrating the cog and pinion in section as well as the cog engaging the teeth of the two racks mounted on a headgear suspension illustrated in cut away; 
           [0033]      FIG. 8  is a plan section illustrating an embodiment of the invention in a locked on closed position; 
           [0034]      FIG. 9  is a plan section illustrating an embodiment of the invention in an unlocked or open position; 
           [0035]      FIG. 10  is a plan section illustrating an embodiment of the invention in a locked or closed position; 
           [0036]      FIG. 11  is a plan section illustrating an embodiment of the invention an unlocked or open position; 
           [0037]      FIGS. 12A , B, and C illustrates a top plan view, a sectional view along line H-H, and a bottom plan view of an embodiment of the an embodiment of knob or cap of the locking mechanism of the present invention; 
           [0038]      FIGS. 13A  and B respectively illustrate a perspective bottom view of an embodiment of a knob or cap of a locking mechanism of an embodiment of the present invention and two racks with the pinion in position mounted on a support and housing on a headgear suspension. 
           [0039]      FIG. 14  is an exploded sectional view of an embodiment of the invention illustrating the knob/cap  14 A, support means  14 B, driver  14 C and housing with pinion  14 D; 
           [0040]      FIG. 15  is an assembled perspective view of attached illustrating a modified cap arrangement with the knob in place  15 A and the knob exploded off  15 B 
       
    
    
       [0041]    The embodiments of the invention are described in the detailed description which follows. Like parts are identified by like reference numbers. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0042]    The present invention provides a locking mechanism for a headgear suspension. The locking mechanism of the invention incorporates a ratchet system with two racks, a driver and a pinion. 
         [0043]    Applications for the suspension headgear locking mechanism of the present invention include hard hats, safety hats, bump hats and any article which uses or requires an adjustable suspension as is commonly used in headgear. 
         [0044]    The invention relates to a lockable knob for a locking mechanism used on a suspension. The invention further relates to the locking mechanism as a whole which incorporates the lockable knob. 
         [0045]    The knob comprises a cap  10  which fits over a head  20  on a support  22 . The head can take on various shapes as illustrated in  FIGS. 4-14  as compared to  FIGS. 15A  and B. In  FIGS. 4-14  the head portion  20  is stellate  18  but in  FIG. 15  the head portion  78  is round and even. The cap  10  is designed to engage the head with a generally snug fit between the cap  10  and the head  20 . The lockable knob comprises a cap portion  10  which engages with a head  20  and can be moved from an unlocked position where the cap  10  is rotatable on the head  20  to a locked position where the cap is locked and cannot rotate. 
         [0046]    The knob and head are engaged to enable the two parts to be turned or rotated together during the rotation to enlarge or narrow the overall circumference of the headgear suspension. 
         [0047]    In the present invention the cap  10  of the lockable knob  4  when viewed from underneath as illustrated in  FIGS. 1 ,  3 A, and  6 , for example, or in sectional view  FIGS. 8 and 9 , has an outer cover which can be grasped by the user for turning. The shape of the cap  10  does not affect the locking mechanism of the invention. In  FIG. 1  the outer surface  11  of cap  10  has protrusions which facilitate grasping the knob. In  FIG. 15  there is a different embodiment illustrated with indentations  76  in the cover which serve, in a different embodiment, the same purpose of facilitating grasping of the knob. 
         [0048]      FIG. 1  illustrates a bottom plan view of a cap  10  of a lockable knob  4  of the present invention. In the view illustrated in  FIG. 1  the cap comprises elements of the locking mechanism of one embodiment wherein there is a radial distribution of resilient arm portions. The arm portions  11  each comprise a lip, or foot  13 . The arms  11  extend from the upper surface  9  of the cap  10  and the foot  13  is located on the arm at a position distal from the top surface  9  of the cap. 
         [0049]    These feet  13  protrude towards the centre of the cap to form at least one lip. 
         [0050]      FIG. 2  illustrates the cap portion  10  of the lockable knob  4  in a top perspective view marked  FIG. 2A . The support  22  ( FIG. 2B ) comprises a head portion  18  (marked generally by bracket  20 ). The support  22  is mountable in a secure fashion to a housing  26  ( FIG. 2C ). 
         [0051]      FIG. 3  further illustrates the four parts of an embodiment of the present inventive locking mechanism namely: a cap ( 3 A), a support ( 3 B), a drive ( 3 C) and a housing ( 3 D). 
         [0052]    A pinion  28  is secured to housing  26  and in this embodiment is an integral, fixed part of housing  26 . 
         [0053]    Drive  24  is rotatably supported on the housing  26 . The drive  24  telescopingly receives a drive end  48  of the pinion  28 . 
         [0054]    It is said the driver telescopingly receives a drive end of a pinion because the driver can move up and down on the pinion. 
         [0055]    In the present embodiment of the invention the drive and pinion are always aligned to allow the drive to drive the pinion when the cap is in the unlocked position. 
         [0056]    The exploded view in  FIG. 5  illustrates the parts again showing the housing  26  engaged with the racks  36  and  38  and better illustrating the pinion  28  and alignment of the parts. 
         [0057]    As illustrated in  FIG. 6 , the cap  10  fits over the head  20 . A central portion  18  defines an opening  31  to receive the drive  24  when in position on head  20 . 
         [0058]      FIGS. 8 and 9  and again in  FIGS. 10 and 11 , cross sectional views of two embodiments of the locking mechanism of the present invention are illustrated in sectional views in both the locked position ( FIGS. 8 and 10 ) and the unlocked position ( FIGS. 9 and 11 ). 
         [0059]    A drive  24  is received within an opening  31  in a head portion  18  from one side of a support  22  and the cap  10  fits over the head  20  on the other side of support  22  engaging one end of the drive  24 . In the embodiment illustrated the drive  24  has one drive end  48  which extends a length  46  from a round plate  50  on which the gear  42  is mounted. The drive  24  defines an opening  44  there-through to receive the pinion  28 . 
         [0060]    The length  46  is selected so the drive end  48  of the drive  24  is received in the opening  52  defined in the under surface  9  of the cap  10 . This is illustrated in  FIGS. 8 and 9 , for example, in cross section. The telescoping effect is observed by the change in volume  70  in  FIG. 8  (locked position) when compared to the volume  72  in  FIG. 9  (unlocked position). 
         [0061]      FIG. 9 , for example, illustrates an unlocked position for the lockable knob and  FIG. 8  illustrates a locked position. As the cap  10  moves from unlocked to locked the drive end  48  telescopes from a first position to a second position and vice versa when the cap  10  moves from locked to unlocked. 
         [0062]    The cap  10  is locked on the head portion  20  when at least one lip is resiliently pushed over a radially extending protuberance  62  located on the head  20 . In this position the cap  10  is no longer free to move because the ring of teeth  16  located on the inner surface  9  of the cap  10  prevent rotation because movement is restricted by interplay with matching grooves  33  on the inner surface of the head  20 . Other mechanisms to fixably engage the cap  10  with the head  20  would work as the head  20  is fixed to a support  22  and does not move in this embodiment 
         [0063]    When the cap  10  is in the locked position the resilient arms  11  spread apart as the feet  13 , which form at least one lip, move over a radial protuberance  60  and when this occurs the cap is prevented from further rotation because the teeth  16  located on the inner surface  9  of the cap (in this embodiment they are centrally located) engage matching grooves  33 , on the head  20  and the cap  10  can no longer turn. 
         [0064]    When the cap is pulled the feet  13  on the resilient arms  11  are able to move over the radial protuberance  60  as the resilience in the arms  11  allow the arms to splay slightly to overcome the resistance of the protuberance  60 . This disengages teeth  16  and permits the cap  10  to freely rotate. The cap  10  does not fall off because the feet  13  are now movably positioned in groove  60  above the protuberance  62 . The feet  13  serve to keep the cap  10  in the grooves  60  and  64  respectively located above and below the radially extending protuberance  62  on the head  10 . 
         [0065]      FIG. 7  illustrates in diagrammatical format the gear teeth  42  engaged with the teeth of the rack. As the gear rotates along the pinion  28  driven by the drive this is translated into movement of the two racks  36  and  38  secured at either end of a suspension strapping. 
         [0066]      FIG. 12B  illustrates a cross section along line H-H of one embodiment of the cap  10  of  FIG. 12A .  FIGS. 12A and 12B  illustrates top plan and bottom plan views respectively. 
         [0067]      FIG. 13  illustrates the housing and support assembled in position over the two racks  36  and  38  with the driver  24  in position. The drive plate  50  to which the gears  42  are attached below (not shown in  FIG. 13 ) and the extending drive end portion  48  with an opening (not shown) therein to receive the pinion  28 . The head portion is not shown in  FIG. 13 . The undersurface  9  of cap  10  is illustrated and the square shaped opening  52  to receive the similarly shaped drive end portion  48  is illustrated. The material  15  defining the opening  52  is shown having a height  17  to telescopically receive the length  46  of the drive end portion  48 . 
         [0068]      FIG. 14  further illustrates the parts in cross section.  FIG. 14A  is the cap of the lockable knob.  FIG. 14B  is the bead of the lockable knob affixed to a support. 
         [0069]      FIG. 14C  illustrates one embodiment of a drive # with an opening there-through to receive a pinion affixed to housing ( FIG. 14D ). 
         [0070]      FIG. 4  is a perspective view of the entire suspension with the locking mechanism of the present invention in place and in a locked position. The suspension strapping  7  (available commercially) receives inserts for racks  36  and  38  which can be molded to the strapping. The locking mechanism of the current invention can be used with any suspension strapping so long as the appropriate rack inserts can be secured to the ends of the strap. 
         [0071]    The locking mechanism of the current invention can be sold separately to manufacturers for use with a wide variety of types and sizes of suspension strapping for various purposes including visors and helmets. 
         [0072]    The locking mechanism of the present invention could be sold as a kit comprising the four parts illustrated, for example, in  FIG. 3  (parts  3 A,  3 B,  3 C and  3 D) either separately or in various combinations or alone. 
         [0073]    The support may comprise a means to snap on to the housing. 
         [0074]    Foam rubber padding may be provided for on the side of the housing which abuts the user&#39;s forehead, for comfort. 
         [0075]    The method, kit, lockable knob and suspension of the present invention permit users to use one hand to readily unlock, adjust and re-lock a suspension for headgear. 
         [0076]    Other features, embodiments, and equivalents would be known to a person skilled in the art and are part of the invention as defined by the claims and description of this specification.