Patent Publication Number: US-9844238-B2

Title: Attachment system for a helmet

Description:
FIELD OF THE INVENTION 
     The invention relates generally to an attachment system for a helmet. 
     BACKGROUND 
     Buckles are used in various types of sports equipment to secure and adjust a fit of the sports equipment to a user wearing the sports equipment. For example, in hockey or lacrosse, a player secures the strap of the chin protector and facemask to a helmet by causing the buckles provided on the left and right ends of the strap to engage buckle mounts provided on the left and right sides of the helmet. 
     Generally, prior art buckles for helmets are provided in the form of snap buttons wherein a female member of a snap button, usually provided on the buckle, is selectively engaged with a male member of the snap button, usually provided on the buckle mount. For example, such a prior art buckle is illustrated in  FIG. 1 . This type of arrangement requires one to push the buckle onto the buckle mount in order to affix it thereto, as shown in  FIG. 2 . However, such prior art buckles have some drawbacks. For instance, pushing the buckle onto the buckle mount generally requires exerting significant strength on the buckle which may cause the user&#39;s finger to hurt as he/she applies pressure on the buckle. Moreover, pushing the buckle onto the buckle mount also causes the user&#39;s head to be pushed from the side, especially when engaging the buckle to the buckle mount requires significant strength. This is generally not comfortable for the user. 
     The present invention aims to alleviate at least in part some of these drawbacks. Similar issues may arise in other sport helmets, such as football, cycling or skateboarding helmets in which users use buckles to secure chin straps together or to secure straps to the helmet. 
     SUMMARY OF THE INVENTION 
     According to a first broad aspect, the invention provides an attachment system for a helmet, the system comprising a buckle and a stud, the buckle extending along a longitudinal axis and having first and second slots that are in a direction transversal to the longitudinal axis of the buckle for receiving a strap in a longitudinal axis of the buckle wherein a length of the strap is adjustable relative to the buckle, the stud being mounted to the helmet or to another strap and comprising an engaging portion, the buckle comprising a rim defining a housing having an opening for receiving the engaging portion, the housing opening extending in a direction that is transversal to the longitudinal axis of the buckle, the rim being configured to allow sliding engagement with the engaging portion in a direction that is transversal to the longitudinal axis of the buckle between a first position wherein a section of the rim retains the engaging portion in the rim housing for locking the buckle into the stud and a second position wherein the engaging portion is no longer retained in the rim housing for releasing the buckle from the stud. 
     According to another broad aspect, the invention provides an attachment system for a helmet, the system comprising a buckle and a stud, the buckle extending along a longitudinal axis and having first and second slots that are in a direction transversal to the longitudinal axis of the buckle for receiving a strap in a longitudinal axis of the buckle wherein a length of the strap is adjustable relative to the buckle, the stud being mounted to the helmet or to another strap and comprising an engaging portion, the buckle comprising a rim defining a housing having an opening for receiving the engaging portion of the stud, the housing opening extending in a direction that is transversal to the longitudinal axis of the buckle, the rim comprising a first material having a first rigidity and the engaging portion comprising a second material having a second rigidity, the first rigidity being less than the second rigidity, the rim being configured to allow sliding engagement with the engaging portion in a direction that is transversal to the longitudinal axis of the buckle between a first position wherein a section of the rim retains the engaging portion in the rim housing for locking the buckle into the stud and a second position wherein the engaging portion is no longer retained in the rim housing for releasing the buckle from the stud. 
     According to a further broad aspect, the invention provides an attachment system for a helmet, the system comprising a buckle and a stud, the buckle extending along a longitudinal axis and having first and second slots that are in a direction transversal to the longitudinal axis of the buckle for receiving a strap in a longitudinal axis of the buckle wherein a length of the strap is adjustable relative to the buckle, the stud being mounted to the helmet or to another strap and comprising an engaging portion having a head and a groove located below the head, the head having a head diameter and a head thickness and the groove having a groove diameter and a groove thickness, the buckle comprising a rim defining a housing having an opening for receiving the engaging portion, the housing opening extending in a direction that is transversal to the longitudinal axis of the buckle, the rim comprising a biasing section with first and second restricting points being spaced apart of a distance taken along the longitudinal axis of the buckle, the rim being configured to allow sliding engagement with the engaging portion in a direction that is transversal to the longitudinal axis of the buckle between first and second positions, wherein, in the first position, the distance between the first and second restricting points is slightly smaller than the groove diameter such that the engaging portion is retained in the rim housing for locking the buckle into the stud, and in the second position, the engaging portion is no longer retained in the rim housing for releasing the buckle from the stud. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A detailed description of embodiments of the invention is provided below, by way of example only, with reference to the accompanying drawings, in which: 
         FIGS. 1 and 2  show a prior art buckle and its implementation on a helmet; 
         FIG. 3  is a perspective view of a helmet comprising a facemask, a chin protector, an adjustable strap and a left buckle in accordance with an embodiment of the invention, the left buckle being in a first (engaged) position; 
         FIG. 4  is a fragmentary side view of the helmet of  FIG. 3 , showing the adjustable strap, the left buckle in a second (disengaged) position and a left stud mounted to the helmet; 
         FIG. 5  is an enlarged view of the components of  FIG. 4  where the left stud is removed from a mount inserted in the helmet shell; 
         FIG. 6  is a cross-sectional view of the stud, mount and a portion of the helmet shell; 
         FIG. 7  is a cross-sectional view of the stud; 
         FIGS. 8A and 8B  are front and bottom views of the buckle; 
         FIG. 9  is a cross-sectional view of the buckle taken along line  9 - 9 ; 
         FIG. 10  is a rear perspective view of the buckle and a portion of the adjustable strap; 
         FIG. 11  shows the buckle and strap portion of  FIG. 10  with the stud and the arrow showing engagement movement of the buckle towards the stud; 
         FIG. 12  is a rear view of the buckle where a section of a rim of the buckle is engaged into the stud, the stud being shown partially broken; 
         FIG. 13  is a rear view of the buckle in the first position where the section of the rim retains the stud in the rim housing for locking the buckle into the stud; 
         FIG. 14A  is a cross-sectional view of the buckle and stud taken along line  14 A- 14 A; 
         FIG. 14B  is a cross-sectional view of the buckle and stud taken along line  14 B- 14 B; 
         FIGS. 15 and 16  show how the buckle is to be engaged and disengaged with the stud respectively, the arrows showing sliding engagement movements; and 
         FIGS. 17 and 18  show a variant of the invention in which the buckle is mounted to an adjustable chin strap and the stud is mounted to another chin strap. 
     
    
    
     It is to be expressly understood that the description and drawings are only for the purpose of illustrating certain embodiments of the invention and are an aid for understanding. They are not intended to be a definition of the limits of the invention. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 3  shows an example of a helmet  2  for wearing by a user. In this example, the helmet  2  is a hockey helmet for use by a hockey player. In this embodiment, the helmet  2  comprises an outer shell  4  for protecting the user&#39;s head, a facemask  6  for protecting the user&#39;s face and a chin protector  8 . An inner side of the outer shell  4  (not shown) comprises padding elements for providing added comfort and impact absorption. In some embodiments, the helmet may not comprise one or more of the above components or may have one or more additional components. 
     The helmet  2  comprises a front portion  10  and a rear portion  12 . The facemask  6  is mounted at the front portion  10  via hinged connections  14  such that the facemask  6  may be selectively opened or closed over the user&#39;s face. The helmet  2  may also comprise a plurality of ventilation apertures in order to allow air to circulate around the head of the user for providing added comfort to the user. The helmet may be a one-piece component or may comprise a plurality of interconnected members. 
     An adjustable chin strap  16  is provided in order to selectively secure the facemask  6  and chin protector  8  in a closed position. In this embodiment, the adjustable chin strap  16  is an elongated strip of fabric comprising ends  18  (only the left end is shown in the drawings). The strap  16  traverses openings in the chin protector  8  and overlaps a portion of wires of the facemask  6  such that the chin protector  8  and facemask  6  are retained together by the strap  16 . A buckle  20  is provided proximate each end  18  of the strap  16 , the buckle  20  being configured for interacting with the strap  16  in order to adjust a functional length of the strap  16  relative to the buckle  20  (i.e., a distance between the chin protector  8  and facemask  6  and the buckle  20 ) and the fit of the chin protector  8  and the facemask  6  with respect to the user&#39;s face, as will be discussed further below. 
     The strap  16  may be configured differently in other embodiments. For instance, in some embodiments, the strap may not extend from one side of the helmet  2  to the other side of the helmet  2 . For example, the strap may be a left strap provided on the left side of the helmet  2  while a similar right strap is provided on the right side of the helmet  2 . 
     With additional reference to  FIGS. 4 to 6 , a stud  22  is mounted to the left side of the helmet  2 . It is understood that a stud  22  is also mounted to the right side of the helmet  2 . As best seen in  FIGS. 5 and 6 , the helmet also comprises a mount  24  at least partially received in an opening  26  of the outer shell  4 . In this embodiment, the mount  24  has a generally cylindrical shape and comprises a centrally positioned fastener portion  28  for receiving a corresponding fastener portion  30  of the stud  22 . A topmost portion  32  of the mount  24  is configured for being inserted into the opening  26  of the outer shell  4 . To this end, the topmost portion  32  of the mount  24  has a shape similar to a shape of the opening  26 , which is generally oblong in this embodiment but may be of any non-circular shape in other embodiments (e.g., square). The non-circular shape of the topmost portion  32  of the mount  24  can prevent a rotational motion of the mount  24  relative to the outer shell  4 . 
     The mount  24  may be affixed to or embedded within a padding element (not shown) of the helmet  2 . For example, the mount  24  may be adhesively bonded onto the padding element or the mount  24  may be at least partially contained within the padding element. The mount  24  may be affixed to the padding element in any other suitable way in other embodiments. 
     The stud  22  comprises the fastener portion  30  and engaging portion  34 . The fastener portion  30  is operable to engage the fastener portion  28  of the mount  24 . In this embodiment, the fastener portion  30  of the stud  22  is a threaded engaging member and the fastener portion  28  of the mount  24  is a corresponding threaded hole for receiving the threaded engaging member. The stud  22  may be mounted to the mount  24  in any other suitable way in other embodiments. 
     As best shown in  FIG. 7 , the engaging portion  34  of the stud  22  defines a head  36 , a groove  38  below the head  36  and a base  40  below the groove  38 . The head  36  defines a diameter D H  and a thickness T H . The groove  38  is located between the head  36  and the base  40  and defines a diameter D G  and a thickness T G . While in this embodiment, the base  40  has the same diameter than the diameter D H  of the head  36  and a thickness that is smaller than the thickness T H  of the head  36  or the thickness T G  of the groove  38 , in other embodiments, the diameter and the thickness of the base  41  may vary. The manner in which the buckle  20  engages stud  22  will be elaborated further below. 
     The stud  22  may be configured differently in other embodiments. For instance, in some embodiments, the stud  22  may not comprise a base at all. In such instances, the topmost portion  32  of the mount  24  may accomplish a similar role to the base  41 . 
     In this embodiment, the stud  22  and mount  24  comprise metallic material (e.g., aluminum). In other embodiments, the stud  22  and mount  24  may comprise a different material such as plastic material or any other suitable material. Moreover, in some embodiments, the stud  22  and mount  24  may comprise different materials from one another, i.e., the stud  22  may comprise one material while the mount  24  may comprise another material. In one embodiment, the stud  22  and/or the engaging portion  34  may comprise a material having a modulus of elasticity E s  that is approximately 69 GPa (i.e., the average modulus of elasticity of aluminum). The modulus elasticity E s  of the material of the stud  22  may have any other value in other embodiments. 
     Although in this embodiment the stud  22  can be selectively attached and detached from the helmet  2  (e.g., by fastening and unfastening the stud  22  to the mount  24 ), in other embodiments, the stud may be configured to be permanently affixed to the helmet  2 . 
     With additional reference to  FIGS. 8A and 8B , the buckle  20  comprises a front side  42 , a rear side  44 , a top side  46  and a bottom side  48 . As shown in  FIG. 8A , the buckle  20  extends along a longitudinal axis  50  from a first end portion  52  to a second end portion  54  and defines a body portion  56  therebetween. In order to interact with the adjustable strap  16  of the helmet  2 , the buckle  20  also comprises first and second slots  58 ,  60  positioned adjacent the first and second end portions  52 ,  54  respectively and being in a direction transversal to the longitudinal axis  50 . In this embodiment, the slots  58 ,  60  are provided with protrusions  62  (e.g., teeth) for providing better retention of the adjustable strap  16 . 
     In order to engage the strap  16  with the buckle  20 , the distal end of the end  18  of the strap  16  is inserted into the first slot  58  from the rear side  44  of the buckle  20  and then inserted into the second slot  60  from the front side  42  of the buckle  20 . Pulling on the distal end of the end  18  of the strap  16  causes the strap  16  to slide along the longitudinal axis  50  of the buckle  20 , causing a reduction in a distance between the chin protector  8  and facemask  6  and the buckle  20  (i.e., the functional length of the strap  16 ) and thus tightening the fit of the chin protector  8  and facemask  6 . Conversely, pulling on the strap  16  at a portion opposite the distal end of the end  18 , i.e., a portion on the other side of the buckle  20 , causes an increase in the distance between the chin protector  8  and facemask  6  and the buckle  20  and thus a loosening of the fit of the chin protector  8  and facemask  6 . As such, the engagement between the buckle  20  and the strap  16  provides adjustability to the fit of the chin protector  8  and facemask  6  with respect to the user&#39;s face. 
     On its rear side  44 , with additional reference to  FIGS. 8 to 11 , the buckle  20  comprises on the body portion  56  a rim  64  located between the first and second slots  58 ,  60  and defining a rim housing  66  for receiving the engaging portion  34  of the stud  22  (i.e. the head  36  and/or groove  38 ). The rim  64  has a shape similar to that of the engaging portion  34  (i.e., circular), however, as best shown in  FIGS. 10 and 11 , the rim housing  66  has a diameter D R  that is slightly bigger than the diameter D G  of the groove  38  (D R &gt;D G ) but that is smaller than the diameter D H  of the head  36  (D R &lt;D H ). As best seen in  FIG. 9 , the rim  64  also has a thickness T R  which is slightly smaller than the thickness T G  of the groove  38  (T R &lt;T G ). The rim  64  further defines a housing opening  68  extending in a direction transversal to the longitudinal axis  35  of the buckle  20 . In this embodiment, the housing opening  68  is located adjacent the bottom side  48  of the buckle  20  and serves as a channel leading towards and into the rim housing  66 . 
     The rim  64  also comprises a biasing section  70  that is configured to elastically deform when subjected to a certain force. That is, the biasing section  70  can deform (e.g., widen) when a certain force is applied at the biasing section  70  and readopt its original form (e.g., retract) when the certain force is no longer applied. In this embodiment, the biasing section  70  comprises two restricting points  70   1 ,  70   2  which can provide the biasing section  70  with biasing functionality. In this example, the biasing section  70  is operable to deform in the longitudinal direction of the buckle  20  such that a longitudinal distance between the two restricting points  70   1 ,  70   2  of the biasing section  70  can vary depending on the force which is applied at the biasing section  70 . As best seen in  FIGS. 8B and 10 , the two restricting points  70   1 ,  70   2  of the biasing section  70  define an “at-rest” longitudinal distance L R  between them when no force is applied at the biasing section  70 . In this embodiment, the at-rest longitudinal distance L R  between the two restricting points  70   1 ,  70   2  of the biasing section  70  is slightly smaller than the diameter D G  of the groove  38  (L R &lt;D G ). 
     As best shown in  FIG. 9 , the rim housing  66  defines a height H B  that may alternatively or additionally be slightly smaller than the thickness T H  of the head  36  of the engaging portion  34  when no force is applied on the buckle  20 . 
     As best shown in  FIG. 8A , the buckle  20  also comprises an indicator portion  72  which is indicative of a direction in which the buckle  20  may be engaged or disengaged from the engaging portion  34 . The indicator portion  72  comprises a sign  74  showing a direction in which the buckle  20  may be engaged or disengaged from the engaging portion  34 . This may help the user more easily and/or quickly engage or disengage the buckle  20  from the engaging portion  34 . In this embodiment, the sign  74  is an arrow showing the direction of sliding movement of the buckle  20  towards the second position (disengaged position). In other embodiments, the housing opening may be located adjacent the top side of the buckle  20  while the indicator portion is located adjacent the bottom side of the buckle  20 . 
     The buckle  20  and/or the rim  64  and/or the biasing section  70  comprises a biasing material that may comprise plastic material. More particularly, in this embodiment, the biasing material comprises polyoxymethylene (POM). The buckle  20  and/or the rim  64  and/or the biasing section  70  may comprise any other plastic material (e.g., nylon, polypropylene) or any other suitable material. The biasing material may have a modulus of elasticity E b  that is approximately 3 GPa (i.e., the average modulus of elasticity of polyoxymethylene). The modulus of elasticity E b  may have any other value in other embodiments. 
     The modulus of elasticity E b  of the biasing material of the buckle  20  and/or the rim  64  and/or the biasing section  70  is smaller than the modulus of elasticity E s  of the material of the stud  22  and/or engaging portion  34  (i.e. the head  36  and/or groove  38 ). In other words, the biasing material of the buckle  20  and/or the rim  64  and/or the biasing section  70  is less rigid than the material of the stud  22  and/or engaging portion  24 , i.e., deforms more easily. The biasing material of the buckle  20  is especially useful at the rim  64  to provide biasing functionality at the biasing section  70 . As such, in some embodiments, the biasing material may be confined to the rim  64  instead of the entirety of the buckle  20 . In any case, the biasing material of the buckle  20  and/or the rim  64  and/or the biasing section  70  has a rigidity which is less than a rigidity of the material of the stud  22  and/or engaging portion  34 . 
     In a similar manner, in some embodiments, a hardness of the biasing material of the buckle  20  and/or the rim  64  and/or the biasing section  70  may be smaller than a hardness of the material of the stud  22  and/or engaging portion  34  (i.e. the head  36  and/or groove  38 ). 
     In order to secure the buckle  20  to the stud  22 , as shown in  FIGS. 11 and 15 , the user aligns the housing opening  68  of the buckle  20  with the stud  22  and slides the rim  64  of the buckle  20  into the groove  38  of the engaging portion  34  such that the head  36  of the engaging portion  34  is received into the rim housing  66  of the buckle  20  and the buckle  20  and rim  64  are in the first position where a section of the rim  64  retains the engaging portion  34  of the stud  22  for locking the buckle  20  onto the stud  22 . 
     More specifically, as the user slides the buckle  20  onto the stud  22 , the groove  38  of the engaging portion  34  contacts the rim  64  at the biasing section  70 . The biasing section  70  resists a progression of the groove  38  further into the buckle  20  to a certain extent since the at-rest longitudinal distance L R  between the two restricting points  70   1 ,  70   2  is slightly smaller than the diameter D G  of the groove  38 . As the user increases a force that he/she applies onto the buckle  20 , the biasing section  70  widens in order to slide over the groove  38 . As best shown in  FIG. 12 , as a result of the increased force, the longitudinal distance between the restricting points  70   1 ,  70   2  of the biasing section  70  increases to an increased distance L I  (L I &gt;L R ). The biasing section  70  retracts once it has overcome the largest part of the groove  38 , i.e., the diameter D G  of the groove  38 . In other words, the longitudinal distance between the restricting points  70   1 ,  70   2  decreases back to the at-rest longitudinal distance L R  once the diameter D G  of the groove  38  has been forced past the biasing section  70 . In the first position, as shown in  FIGS. 13, 14A and 14B , the head  36  of the engaging portion  34  is contained in the rim housing  66  and the buckle  20  is locked onto the stud  22  since removing the buckle  20  from engagement with the stud  22  requires applying an increased force in the opposite transversal direction in order to overcome the resistance posed by the biasing section  70 . As such, in the first position, the biasing section  70  retains the head  36  of the stud  22  in the rim housing  66 . 
     In embodiments where the height H B  of the biasing section  70  is slightly smaller than the thickness T H  of the head  36 , the biasing section  70  may similarly be operable to deform under force and thus increase its height H B  in order to slide over the head  36  of the engaging portion  34 . 
     In order to remove the buckle  20  from engagement with the stud  22 , as shown in  FIG. 16 , the user slides the buckle  20  in a direction opposite to the housing opening  68  and thus towards the top side  46  of the buckle  20  from the first engaged position to the second disengaged position where the engaging portion  34  of the stud  22  will no longer be retained in the rim housing  66  for releasing the buckle  20  from the stud  22 . To this effect, as the groove  38  contacts the biasing section  70  and the user increases the force he/she applies on the buckle  20 , the biasing section  70  expands to slide over the largest part of the groove  38 , i.e., the diameter D G  of the groove  38 . In other words, the longitudinal distance between the two restrictive points  70   1 ,  70   2  of the biasing section  70  increases to the increased distance L I . As the stud  22  is cleared through the housing opening  68 , and the head  36  is no longer retained in the rim housing  66 , the biasing section  70  retracts again, i.e., the longitudinal distance between the two restrictive points  70   1 ,  70   2  returns to the at-rest longitudinal distance L R . 
     The buckle  20  is configured to allow sliding engagement with the stud  22  in a direction transversal to the longitudinal axis  50  of the buckle and also generally transversal to a direction of a force applied when the facemask  6  is impacted or pulled, which is generally a front-to-back direction. This may prevent accidental disengagement of the buckle  20  with the stud  22 . For example, if the facemask  6  is pulled frontwardly or pushed rearwardly, the force will be applied generally in a longitudinal direction of the helmet  2 . Since the housing opening  68  is the only way through which the buckle  20  can become disengaged from the stud  22  and the housing opening  68  is located adjacent the bottom side  48  of the buckle  20 , applying a force in a longitudinal direction that is generally parallel to the longitudinal direction of the buckle  20  cannot disengage the buckle  20  from the stud  22 . Instead, as discussed above, a force strong enough to overcome the resistance posed by the biasing section  70  must be applied in a direction transversal to the longitudinal direction of the buckle  20  (to the longitudinal axis  50 ) in order for the buckle  20  to become disengaged from the stud  22 . 
     As described above, the interaction between the buckle  20  and the stud  22  may rely at least in part on the different dimensions that were defined in respect of the rim  64 , the rim housing  66 , the biasing section  70 , and the engaging portion  34  of the stud  22  (i.e. the head  36  and/or groove  38 ). For example, as mentioned earlier, the at-rest longitudinal distance L R  between the two restrictive points  70   1 ,  70   2  of the biasing section  70  is slightly smaller than the diameter D G  of the groove  38  of the engaging portion  34  of the stud  22 . However, if the at-rest longitudinal distance L R  is too small with respect to the diameter D G  of the groove  38 , the biasing material of the buckle  20  may not be able to elastically deform sufficiently to allow the stud  22  into the rim housing  66 . As such, the at-rest longitudinal distance L R  has a tolerance with respect to the diameter D G  of the groove  38  which defines how much smaller than the diameter D G  the at-rest longitudinal distance L R  can be. For instance, in some cases, the tolerance of the at-rest longitudinal distance L R  with respect to the diameter D G  of the groove  38  may be up to 2%. That is, the at-rest longitudinal distance L R  may be up to 2% smaller than the diameter D G  of the groove  38 . In some cases this tolerance may be between 2% to 4%, in some cases between 4% to 6%, and in some cases even up to 8%. Similarly, in some embodiments, the height H B  of the biasing section  70  of the rim  64  has a tolerance with respect to the thickness T H  of the head  36  of the engaging portion  34  of the stud  22 . For instance, in some cases the tolerance of the height H B  of the biasing section  70  with respect to the thickness T H  of the head  36  may be up to 2%. That is, in some cases, the height H B  of the biasing section  70  may be up to 2% smaller than the thickness T H  of the head  36 . In some cases this tolerance may be between 2% to 4%, in some cases between 4% to 6%, and in some cases even up to 8%. 
       FIGS. 17 and 18  show a helmet  202  that does not comprise a facemask or a chin protector and that may comprise a visor that covers at least the eyes of the user. The helmet  202  comprises left and right ear loops  204 ,  206  on the left and right sides of the helmet, an adjustable chin strap  208  with a proximal end connected to the ear loop  204 , a buckle  210  for securing the adjustable chin strap  208  and for providing functional length adjustment of the strap  208  relative to the buckle  210  (i.e., adjustment of the distance between the ear loop  204  and the buckle  210 ), and a stud  212  mounted to a chin strap  214  having a proximal end connected to the ear loop  206 . 
     The adjustable chin strap  208  is thus permanently affixed to the ear loop  204 . This can be achieved by affixing an end of the adjustable chin strap  208  onto itself around the ear loop  204  via stitching or ultrasonic welding for example. On the opposite side of the helmet  202 , the chin strap  214  is also permanently affixed to the ear loop  206  in a similar way as the adjustable chin strap  208  is affixed to the ear loop  204 . The chin strap  214  is “fixed” in that its length cannot be modified by the user whereas the adjustable chin strap  208  is “adjustable” in that its functional length (i.e., the distance between the ear loop  204  and the buckle  210 ) is adjustable by the user by way of its interaction with the buckle  210 . 
     As best shown in  FIG. 18 , the stud  212  is provided on a front side of the chin strap  214 . 
     The buckle  210  is similar to the buckle  20 . For example, the buckle  210  comprises a housing and a housing opening for interacting with a engaging portion of the stud  212 . The user of the helmet  202  may adjust the length of the adjustable chin strap  208  via its engagement with the buckle  210  in a similar manner to that described above in respect of the strap  16 , allowing the user to adjust the length of the chin strap  208  with respect to his/her chin. 
     Similarly to the buckle  20  described above, the buckle  210  may be slid in and out of engagement with the engaging portion of the stud  212  (e.g., in a direction indicated by a sign or an indicator portion of the buckle  220 ). This provides an easy way to secure the buckle  210  to the stud  212  and thus to secure the helmet  202  onto the user&#39;s head. 
     In some embodiments, the buckle  20  and the buckle  210  may be configured to allow both a sliding engagement and a snapping engagement with a respective stud. For instance, taking the buckle  20  as an example, the rim housing of the buckle may be dimensioned as previously described to allow the buckle to slideably engage the stud and, additionally, also be dimensioned such that buckle may be snapped or unsnapped from the stud in a more traditional way. In such an embodiment, the diameter D H  of the head has a tolerance relationship with respect to the diameter D R  of the rim housing which defines how much smaller the diameter D R  of the rim housing can be relative to the diameter D H  of the head. For instance, in some cases, the tolerance of the diameter D R  with respect to the diameter D H  of the head may be up to 2%. That is, the diameter D R  may be up to 2% smaller than the diameter D H  of the head. In some cases this tolerance may be between 2% to 4%, in some cases between 4% to 6%, and in some cases even up to 8%. As such, the buckle may be provided with dual functionality that allows the buckle to slideably engage and disengage the stud and also to be used in a more traditional way which involves snapping and unsnapping the buckle from the stud. 
     Any feature of any embodiment discussed herein may be combined with any feature of any other embodiment discussed herein in some examples of implementation. Certain additional elements that may be needed for operation of certain embodiments have not been described or illustrated as they are assumed to be within the purview of those of ordinary skill in the art. 
     Moreover, certain embodiments may be free of, may lack and/or may function without any element that is not specifically disclosed herein. Although various embodiments and examples have been presented, this was for the purpose of describing, but not limiting, the invention. Various modifications and enhancements will become apparent to those of ordinary skill in the art and are within the scope of the invention, which is defined by the appended claims.