Field of the invention
[0001] The invention relates to a length adjustment mechanism for a strap.
 
            Background of the invention
[0002] U.S. Patent 3,214,809 issued to Edwards on December 20, 1963 discloses a length adjustment
               mechanism for a strap having overlapping portions. U.S. Patent 5,950,245 issued to
               Binduga on September 14, 1999 discloses an adjustable headband comprising a ratchet
               mechanism having different resistances.
 
            [0003] Although these prior art adjustable mechanisms allow adjusting the length of a strap
               when desired by the user while normally preventing undesirable movement of the strap,
               such movement is nevertheless possible when the force applied to the strap exceeds
               a certain level.
 
            [0004] Against this background, there is a need in the industry for a mechanism that allows
               the length of the strap to be easily adjusted by the user while preventing or at least
               reducing the possibility of unwanted loosening or tightening of the strap.
 
            Summary of the Invention
[0005] As embodied and broadly described herein, the invention seeks to provide a length
               adjustment mechanism for a strap having a row of teeth. The mechanism comprises a
               pinion for meshing with the row of teeth and a finger operable actuator pivotable
               in a first direction and in a second direction. The mechanism also comprises a pivoting
               link coupled to the pinion, the pivoting link being pivotable about a first pivot
               axis to impart a pivotal movement to the pinion and a rotating element coupled with
               the finger operable actuator. The rotating element is pivotable about a second pivot
               axis and engages the pivoting link in a driving relationship such that movement imparted
               to the finger operable actuator is communicated to the pinion via the rotating element
               and the pivoting link to displace the row of teeth.
 
            Brief description of the drawings
[0006] A detailed description of the preferred embodiments of the present invention is provided
               herein below, by way of example only, with reference to the accompanying drawings,
               in which:
               
               
Figure 1 is a perspective view of a strap having a length adjustment mechanism constructed
                  in accordance with a first embodiment of the invention;
               Figure 2 is a perspective exploded view of the mechanism of Figure 1;
               Figure 3 is an elevational exploded view of the mechanism of Figure 2;
               Figure 4 is a perspective enlarged view of the mechanism, the finger operable actuator
                  of the mechanism being omitted;
               Figure 5 is a plan view of the mechanism of Figure 4, arrows showing directions in
                  which components pivot;
               Figure 6 is a plan view of the mechanism of Figure 4, arrows showing forces acting
                  between the pivoting link and pinions;
               Figure 7 is a perspective view of a ski boot having straps with a length adjustment
                  mechanism constructed in accordance with a second embodiment;
               Figure 8 is a perspective exploded view of the mechanism of Figure 7; and
               Figure 9 is an elevational exploded view of the mechanism of Figure 8.
 
            [0007] In the drawings, preferred embodiments of the invention are illustrated by way of
               examples. It is to be expressly understood that the description and drawings are only
               for the purpose of illustration and are an aid for understanding. They are not intended
               to be a definition of the limits of the invention.
 
            Detailed description of preferred embodiments
[0008] Figures 1 to 6 show a length adjustment mechanism 1 constructed in accordance with
               a first embodiment of the invention, mechanism 1 being mounted on a strap 10 for adjusting
               the length of the strap 10.
 
            [0009] Strap 10 comprises first and second overlapping portions 12 and 14. Overlapping portions
               12 and 14 have respective first and second elongated slots 16 and 18 with opposite
               first and second rows of teeth 20 and 22. Elongated slots 16 and 18 are in general
               alignment.
 
            [0010] Mechanism 1 comprises a pinion 24 having teeth meshing with first and second rows
               of teeth 20 and 22. Pinion 24 is coupled to a pivoting link 26. A disc 28 is provided
               between pinion 24 and pivoting link 26. Preferably, pinion 24, pivoting link 26 and
               disc 28 are integrally formed. Thus, pinion 24, pivoting link 26 and disc 28 are pivotable
               about a first pivot axis A1 and pivoting link 26 imparts a pivotal movement to pinion
               24 (and disc 28).
 
            [0011] It is understood that it is not essential that disc 28 pivots and be integrally formed
               with pinion 24 and/or pivoting link 26. While pinion 24 is coupled to pivoting link
               26 and pivots about first pivot axis A1, it is also understood that this pinion may
               pivot about another pivot axis or may be coupled to pivoting link 26 via another driving
               component which pivots about first pivot axis A1.
 
            [0012] Pivoting link 26 comprises first and second surfaces 30, 32 that define therebetween
               an angle less than 180°, and third and fourth surfaces 34, 36 that also define therebetween
               an angle less than 180°.
 
            [0013] Mechanism 1 further comprises a finger operable actuator 38 having a gripping portion
               40 for allowing a user to turn the finger operable actuator 3 8 in a first direction
               D 1 or in a second direction D2 that is opposite to direction D1. Finger operable
               actuator 38 also comprises first and second lugs 42, 44 projecting downwardly and
               engaging respective second and third satellite rotating elements 46, 48 in order to
               communicate movement of finger operable actuator 38 to rotating elements 46, 48. In
               the illustrated embodiments, rotating elements 46, 48 are formed of pinions but it
               is understood that other types of rotating elements can be used without departing
               of the scope of the present invention.
 
            [0014] Second rotating element 46 is pivotable about a second pivot axis A2 and third rotating
               element 48 is pivotable about a third pivot axis A3. Second rotating element 46 comprises
               a first circular section 46T having teeth and a second circular section 46S being
               free of teeth. Similarly, third rotating element 48 comprises a first circular section
               48T having teeth and a second circular section 48S being free of teeth.
 
            [0015] Mechanism 1 further includes a casing 50 having an elongated aperture 52 for receiving
               overlapping portions 12, 14. Casing 50 has a ring gear 54 with an annular peripheral
               projection 56 having an internal surface 58 from which originate the teeth of the
               ring gear. As shown on Figures 2 and 5, the diameter of disc 28 is substantially identical
               to the diameter of ring gear 54 and fits in the peripheral projection 56 in order
               to properly support rotating elements 46, 48 that are located above disc 28.
 
            [0016] Referring now more specifically to Figures 4 to 6, teeth of first circular sections
               46T, 48T of second and third rotating elements 46, 48 mesh with ring gear 52, while
               the second circular section 46S of the second rotating element 46 contacts the first
               and second surfaces 30, 32 of pivoting link 26. Similarly, the second circular section
               48S of third rotating element 48 contacts the third and fourth surfaces 34, 36 of
               pivoting link 26. Second and third rotating elements 46, 48 are therefore frictionally
               engage with pivoting link 26 in a driving relationship such that pivotal movement
               of finger operable actuator 38 is communicated to pinion 24 via rotating elements
               46, 48 and pivoting link 26, causing first and second overlapping portions 12, 14
               to be displaced in opposite directions to either loosen or tighten the strap 10.
 
            [0017] More specifically, when the finger operable actuator 38 is turned by hand, the motion
               imparts opposite pivotal movement to second and third satellite rotating elements
               46, 48 about the second and third pivot axes A2, A3, respectively. Since the teeth
               of first circular sections 46T, 48T mesh with ring gear 54, satellite rotating elements
               46, 48 also pivot in an orbital fashion about first pivot axis A1 in the same direction
               as finger operable actuator 38.
 
            [0018] Furthermore, since a portion of second circular section 46S contacts a portion of
               first and second surfaces 30, 32 of pivoting link 26 and a portion of second circular
               section 48S contacts a portion of first and second surfaces 34, 36 of pivoting link
               26, the orbital pivotal movement of rotating elements 46, 48 imparts a pivotal movement
               to pivoting link 26 about the first pivot axis A1.
 
            [0019] As pivoting link 26 is coupled to pinion 24, the pivotal movement of the pivoting
               link 26 imparts pivotal movement of pinion 24 in order to displace first and second
               overlapping portions 12, 14 in opposite directions. Thus, pivotal movement of finger
               operable actuator 38 in one direction tightens the strap 10 by moving the overlapping
               portions 12, 14 toward one another. Conversely, the pivotal movement of the finger
               operable actuator 38 in the opposite direction loosens the strap 10 by moving the
               overlapping portions 12, 14 away from one another.
 
            [0020] When a force is applied on the strap 10 for loosening or tightening it, such as when
               the overlapping portions 12, 14 are pulled away or pushed toward one another, the
               teeth 20, 22 tend to impart a turning movement to pinion 24 and to pivoting link 26.
               However, the driving relationship between the satellite rotating elements 46, 48 and
               pivoting link 26 is unidirectional such that the satellite rotating elements 46, 48
               and the pivoting link 26 interlock, thus preventing the any one of the rotary components
               (finger operable actuator 38, satellite rotating elements 46, 48, pivoting link 26
               and pinion 24) from turning.
 
            [0021] In other words, relative movement between the overlapping portions 12, 14 of strap
               10 is precluded when a force is applied to pinion 24 tending to drive pivoting link
               26. A turning force imparted on pivoting link 26 by the pivot 24 is transmitted to
               satellite rotating elements 46, 48. The forces acting on the satellite rotating elements
               46, 48 are shown at F 1 and F2 in Figure 6. The geometry of the various parts is such
               that forces F 1 and F2 intersect the respective pivot axes of the satellite rotating
               elements 48, 48, thus interlocking the mechanism.
 
            [0022] Figure 8 shows a length adjustment mechanism 100 constructed in accordance with a
               second embodiment of the invention, mechanism 100 being mounted on a strap 110. Mechanism
               100 for adjusting strap 110 is identical to that of mechanism 1, and the only difference
               resides in the construction of the strap 110 that has a single part 112 including
               a row of teeth 114 that can be moved forward or backward such as to tighten or loosen
               the strap 110.
 
            [0023] It will become apparent to a person skilled in the art that the mechanism of the
               present invention may be used for adjusting the length of a strap in a wide variety
               of applications, such as the strap forming the headband on a helmet. The mechanism
               of the present invention may also be used for adjusting the length of a strap for
               fastening footwear.
 
            [0024] The above description of preferred embodiments should not be interpreted in a limiting
               manner since other variations, modifications and refinements are possible within the
               spirit and scope of the present invention. For example, friction drive rollers may
               replace the various pinions of the mechanism. Also, instead of using a pair of satellite
               pinions 46, 48, a single satellite pinion can be used. The scope of the invention
               is defined in the appended claims and their equivalents.
 
          
         
            
            1. A length adjustment mechanism (1) for a strap (10) having a row of teeth, said mechanism
               (1) comprising:
               
               
a) a pinion (24) for meshing with the row of teeth (20);
               
               b) a finger operable actuator (38) pivotable in a first direction (D1) and in a second
                  direction (D2);
               
               c) a pivoting link (26) coupled to said pinion (24), said pivoting link (26) being
                  pivotable about a first pivot axis (A1) to impart a pivotal movement to said pinion
                  (24); and
               
               d) a rotating element (46) coupled with said finger operable actuator (38), said rotating
                  element (46) being pivotable about a second pivot axis (A2), said rotating element
                  (46) engaging said pivoting link (26) in a driving relationship such that movement
                  imparted to said finger operable actuator (38) is communicated to said pinion (24)
                  via said rotating element (46) and said pivoting link (26) to displace the row of
                  teeth (20).
  
            2. A length adjustment mechanism (1) as defined in claim 1, wherein when a force is applied
               to said pinion (24) tending to pivot said pivoting link (26), said pivoting link (26)
               and said rotating element (46) interlocking for resisting pivotal movement of said
               pivoting link (26).
 
            3. A length adjustment mechanism (1) as defined in claim 1 or 2 wherein said pivoting
               link (26) comprises first and second surfaces (30, 32) defining therebetween an angle
               less than 180°, a portion of said first and second surfaces (30, 32) of said pivoting
               link (26) contacting a portion of said rotating element (46).
 
            4. A length adjustment mechanism (1) as defined in any one claims 1 to 3 wherein said
               pinion (24) is pivotable about said first pivot axis (A1).
 
            5. A length adjustment mechanism (1) as defined in any one of claims 1 to 4 further comprising
               a casing (50) having an elongated aperture (52) for receiving a portion of the strap
               (10), said casing (50) further comprising a ring gear (54) encircling said first pivot
               axis (A1).
 
            6. A length adjustment (1) as defined in any one of claims 1 to 5 wherein said pinion
               (24) is a first pinion and said rotating element (46) is a second pinion, said second
               pinion being meshed with said ring gear (54).
 
            7. A length adjustment mechanism (1) as defined in any one of claims 1 to 6 wherein said
               second pinion (46) comprises a first section (46T) including teeth meshed with said
               ring gear (54) and a second section (46S) frictionally engaging said pivoting link
               (26).
 
            8. A length adjustment mechanism (1) as defined in any one of claims 1 to 7 wherein said
               second section (46S) of said second pinion (46) is free of teeth.
 
            9. A length adjustment mechanism (1) as defined in any one of claims 1 to 8 wherein when
               said second pinion (46) and said pivoting link (26) interlock, said pivoting link
               (26) applies a force on said second pinion (46) that is oriented along an axis intersecting
               said second pivot axis (A2).
 
            10. A length adjustment mechanism (1) as defined in any one of claims 1 to 9 further comprising
               a third pinion pivotable (48) about a third pivot axis (A3), said third pinion (48)
               being coupled with said finger operable actuator (38) and meshed with said ring gear
               (54), said third pinion (48) engaging said pivoting link (26) in a driving relationship
               such that movement of said finger operable actuator (38) is communicated to said first
               pinion (24) via said third pinion (48) and said pivoting link (26) to displace the
               row of teeth (20).
 
            11. A length adjustment mechanism (1) as defined in any one of claims 1 to 10 wherein
               said third pinion (48) comprises a first section (48T) including teeth meshed with
               said ring gear (54) and a second section (48S) frictionally engaging said pivoting
               link (26).
 
            12. A length adjustment mechanism (1) as defined in any one of claims 1 to 11 wherein
               said second section (48S) of said third pinion (48) is free of teeth.
 
            13. A length adjustment mechanism (1) as defined in any one of claims 1 to 12 wherein
               said force is a first force and said pivoting link (26) comprises third and fourth
               surfaces (34, 36) defining therebetween an angle less than 180°, and wherein when
               said third pinion (48) and said pivoting link (26) interlock, said pivoting link (26)
               applies a second force on said third pinion (48) that is oriented along an axis intersecting
               said third pivot axis (A3 ) .
 
            14. A length adjustment mechanism (1) as defined in any one of claims 1 to 13 wherein
               said pivoting link (26) is connected to said first pinion (24), said pivoting link
               (26) being located above said first pinion (24).
 
            15. A length adjustment mechanism (1) as defined in any of claims 1 to 14 further comprising
               a disc (28), said disc (28) being located between said pivoting link (26) and said
               first pinion (24).
 
            16. A length adjustment mechanism (1) as defined in any of claims 1 to 15 wherein said
               pivoting link (26), said disc (28) and said first pinion (24) are integrally formed.
 
            17. A length adjustment mechanism (1) as defined in any of claims 1 to 16 wherein said
               ring gear (54) comprises an annular peripheral projection (56) having an internal
               surface (58) from which originate teeth, said ring disc (28) has a disc diameter and
               said ring gear (54) has a ring diameter, said disc diameter being substantially identical
               to said ring diameter.
 
            18. A length adjustment mechanism (1) as defined in any of claims 1 to 17 wherein said
               section (46) and third pinion (48) are located above said disc (28).
 
            19. A length adjustment mechanism (1) as defined in any of claims 1 to 18 wherein said
               finger operable actuator (38) comprises first and second lugs (42, 44) projecting
               downwardly along said second (A2) and third pivot axes (A3), said first and second
               lugs (42, 44) engaging said second (46) and third pinions (48) such that said second
               (46) and third (48) pinions pivot upon actuation of said finger operable actuator
               (38).
 
            20. A length adjustment mechanism (1) as defined in any of claims 1 to 19 wherein said
               finger operable actuator (38) is a knob having a gripping portion (40).
 
            21. A length adjustment mechanism (1) as defined in any of claims 1 to 20 wherein a portion
               of said second section (46S) of said second pinion (46) contacts a portion of said
               internal surface of said ring (28) and a portion of said second section (48S) of said
               third pinion (48) contacts another portion of said internal surface of said ring (28)
               .
 
            22. An adjustable strap having a length mechanism as defined in claim 1.
 
            23. A headband having the strap as defined in claim 22, said headband further comprising
               crown straps attached to said strap.
 
            24. A helmet comprising the headband as defined in claim 23.
 
            25. An article of footwear comprising the strap as defined in claim 22.