Patent Publication Number: US-8991009-B1

Title: Adjustable self-closing butterfly fence hinge

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. application Ser. No. 14/099,014 filed Dec. 6, 2013, and entitled Adjustable Self-Closing fence Hinge, incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This disclosure relates to the field of fence hinges. More particularly, this disclosure relates to a butterfly fence hinge system configured to have an adjustable spring tension. 
     BACKGROUND 
     Gate hinges for fences desire improvement. Conventional self-closing (or self-opening) gate hinges desire improvement in that they are difficult to adjust the spring tension, or to wholly remove spring tension. 
     The present disclosure advantageously provides a spring-loaded butterfly fence hinge system that enables convenient adjustment of the spring tension, including complete removal of spring tension. 
     SUMMARY 
     The above and other needs are met by an adjustable self-closing fence hinge system. 
     In one aspect, the hinge system includes a base plate attachable to a fence post, the base plate including a base plate hinge mount having a bore with a plurality of internal recesses; a swing arm attachable to a fence gate and including a swing arm hinge mount; and a hinge mounted to the base plate hinge mount and the swing arm hinge mount for hingedly connecting the base plate and the swing arm to permit the swing arm to pivot relative to the base plate. 
     In one embodiment, the hinge includes a tension spring having a first end and an opposite second end, the second end of the tension spring being fixed relative to the swing arm hinge mount, a pin having a head including a plurality of projections about a circumference of the head and an opposite end of the pin spaced from the head. The projections of the head are configured to be received by the recesses of the base plate hinge mount, and the pin is positioned to extend through the base plate hinge mount and the swing arm hinge mount and to cooperate with the tension spring so that a first end of the spring is fixed relative to the head of the pin, and when the head of the pin is rotated the first end of the spring also rotates. 
     Tension of the spring is fixed when the pin head is seated in the base plate hinge mount with the projections of the head of the pin received in the recesses of the bore. Tension of the spring is adjustable by withdrawing the projections of the head of the pin from engagement with the recesses of the bore of the base plate hinge mount, then rotating the head of the pin to wind or unwind the tension spring to adjust the tension of the tension spring, and then positioning the projections of the head into engagement with the recesses of the bore of the base plate hinge mount, thereby fixing the tension of the tension spring at the adjusted tension. 
     A compression spring may be located between the swing arm hinge mount and the opposite end of the pin to urge the opposite end of the pin away from the base plate hinge mount. In such case, in connection with withdrawing the projections of the pin away from the recesses of the head, a force is applied to compress the compression spring to urge the head of the pin away from the base plate hinge mount. 
     In another embodiment, the hinge system includes a base plate attachable to a fence post, the base plate including a first base plate hinge mount having a bore with a plurality of internal recesses and a second base plate hinge mount spaced from the first base plate hinge mount. A swing arm is attachable to a fence gate, the swing arm and includes a first swing arm hinge mount and a second swing arm hinge mount spaced from the first swing arm hinge mount. 
     A hinge is mounted to the base plate hinge mounts and the swing arm hinge mounts for hingedly connecting the base plate and the swing arm to permit the swing arm to pivot relative to the base plate. The hinge includes a tension spring having a first end and an opposite second end, the second end of the tension spring being fixed relative to the first swing arm hinge mount. The hinge also includes a pin having a head including a plurality of projections about a circumference of the head and an opposite end of the pin spaced from the head. The projections are configured to be received by the recesses of the first base plate hinge mount. The pin is positioned to extend through the base plate hinge mounts and the swing arm hinge mounts and to cooperate with the tension spring so that a first end of the spring is fixed relative to the head of the pin so that when the head of the pin is rotated the first end of the spring also rotates. A compression spring is located between the second swing arm hinge mount and the opposite end of the pin to urge the opposite end of the pin away from the base plate hinge mounts. 
     Tension of the spring is fixed when the pin head is seated in the base plate hinge mount with the projections of the head of the pin received in the recesses of the bore. Tension of the spring is adjustable by applying force to compress the compression spring to urge the head of the pin away from the base plate hinge mount and withdrawing the projections of the head of the pin from engagement with the recesses of the bore of the base plate hinge mount, then rotating the head of the pin to wind or unwind the tension spring to adjust the tension of the tension spring, and then positioning the projections of the head into engagement with the recesses of the bore of the base plate hinge mount, thereby fixing the tension of the tension spring at the adjusted tension. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages of the disclosure are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
         FIG. 1  is a frontal upper perspective view of a fence hinge system according to the disclosure as mounted onto a fence post and fence gate. 
         FIG. 2  is a frontal lower perspective view of the fence hinge system of  FIG. 1 . 
         FIG. 3  is a rear upper perspective view of the fence hinge system of  FIG. 1 . 
         FIG. 4  is a rear lower perspective view of the fence hinge system of  FIG. 1 . 
         FIGS. 5 and 6  are front and rear perspective views of the fence hinge system of  FIG. 1 , with a base plate component and a swing arm component of the fence hinge system transparent to show a hinge component. 
         FIGS. 7 and 8  are partially exploded views of the fence hinge system of  FIG. 1 . 
         FIG. 9  is an exploded view showing hinge components. 
         FIGS. 10 and 11  are perspective views of a base plate component of the fence hinge system of  FIG. 1 . 
         FIGS. 12 and 13  are perspective views of a swing arm component of the fence hinge system of  FIG. 1 . 
         FIG. 14  depicts adjustment of spring tension of the hinge system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the drawings, the disclosure relates to an adjustable self-closing butterfly hinge system  10 . The hinge system  10  is configured to enable an adjustable closing or opening tension. The term self-closing as used herein will be understood to encompass reverse mounting of the hinge so as to be self-opening. 
     The hinge system  10  is configured for mounting onto a body, such as a post P and/or a gate G of a fence ( FIG. 1 ), and includes a base plate  12 , a swing arm  14 , and a hinge  16 . 
     The base plate  12  is desirably of one-piece stamped metal construction and is configured for mounting onto the post P. In this regard, the base plate  12  includes a front wall  20  mountable to the front of the post P and one or more lips  22  positionable against a side of the post adjacent the gate G. For use with a square post P, the front wall  20  and the lips  22  generally form an angle of 90 degrees. The front wall  20  includes mounting apertures  24  configured for receiving fasteners such as screws for mounting the base plate  12  to the post P. The front wall  20  includes outwardly extending and vertically spaced apart and aligned hinge mounts  26  and  28  onto which components of the hinge  16  are rotatably or pivotally mounted, as explained more fully below. The lips  22  are preferably located adjacent to and extend from the hinge mounts  26  and  28 . 
     The mounts  26  and  28  extend from an edge  30  of the base plate  12  so as to extend in a direction toward the swing arm  14  when the hinge  10  is assembled. The mount  26  is located adjacent an end  32  of the base plate  12 . The mount  28  is spaced from the mount  26 , and spaced from an opposite end  34  of the base plate  12 , to define a gap G between the mounts  26  and  28 . 
     The mount  26  is generally configured as a cylinder, having a generally circular through-bore  40  with opposite open ends  42  and  44 . A longitudinal groove  46  is defined along the length of the bore  40  and extends through both of the ends  42  and  44 . The end  42  and a portion of the bore  40  adjacent the end  42 , typically about half of the length of the bore  40 , is configured to include a plurality of uniformly spaced apart recesses  48 . 
     The mount  28  is generally configured as a filled cylinder, but having a circular and centrally located through-bore  50  with opposite open ends  52  and  54 . The bore  50  is small at the end  52 , but may increase in diameter at the end to provide a countersunk opening  56  so that a reduced surface area is provided for reducing friction for opening and closing of the hinge. 
     The swing arm  14  is desirably of one-piece metal construction and is configured for mounting onto the gate G. In this regard, includes a front wall  60  mountable to the front of the gate G and one or more lips  62  positionable against a side of the gate G adjacent the post P, with the front wall  60  and the lips  62  generally form an angle of 90 degrees. The front wall  60  includes mounting apertures  64  configured for receiving fasteners such as screws for mounting the swing arm  14  to the gate G. The front wall  60  includes outwardly extending and vertically spaced apart and aligned hinge mounts  66  and  68  onto which components of the hinge  16  are rotatably or pivotally mounted, as explained more fully below. The lips  62  are preferably located adjacent to and extend from the hinge mounts  66  and  68 . 
     The mounts  66  and  68  extend from an edge  70  of the swing arm  14  so as to extend in a direction toward the base plate  12  when the hinge  10  is assembled. The mount  66  is located adjacent an end  72  of the swing arm  14 . The mount  68  is spaced from the mount  66 , and spaced from an opposite end  74  of the swing arm  14 , to define a gap G′ between the mounts  66  and  68 . In this regard, the gap G of the mounts  26  and  28  cooperates with the gap G′ of the mounts  66  and  68  to provide a dove-tailed fit of the mounts of the base  12  and the mounts of the swing arm  14 . Thus, the mount  66  of the swing arm  14  fits between the mounts  26  and  28  of the base plate  12 , and the mount  28  of the base plate  12  fits between the mounts  66  and  68  of the of the swing arm  14 . 
     The mount  66  is generally configured as a cylinder, having a generally circular through-bore  80  with opposite open ends  82  and  84 . A longitudinal groove  86  is defined along the length of the bore  80  and extends through both of the ends  82  and  84 . An interior lip  80   a  is located on the bore  80  adjacent the end  82 . A notch  88  is defined through the sidewall of the mount  66  adjacent the end  84 . 
     The mount  68  is generally configured as a filled cylinder, but having a circular and centrally located through-bore  90  with opposite open ends  92  and  94 . The bore  90  is small at the end  92 , but increases in diameter in a stepped configuration at the end  94 , so as to provide a stepped, concentric opening  96 . 
     The hinge  16  includes a tubular hinge housing  100  enclosing a hinge spring  102 , and a spring adjustment system  104  that cooperates with the base plate  12 , the swing arm  14  to enable adjustment of the tension of the hinge spring  102 . 
     The tubular housing  100  of the hinge  16  is preferably of metal construction and includes a through bore  106  sized to receive the spring  102 . The spring  102  is preferably a torsion spring having opposite ends  102   a  and  102   b . A flanged split ring  108  receives the housing  100  and is positioned to interface between the mounts  26  and  66  to provide a smooth pivot surface to facilitate pivotal movement of the swing arm  14  relative to the base plate  12 . The flange portion of the split ring  108  is configured to seat on the lip  80   a  of the mount  66 . 
     The spring adjustment system  44  includes an index pin  110  having a head  112  and an opposite grooved end  114  onto which is seated a fastener, such as a C-clip  116 . The head  112  includes an aperture  112   a  extending through the thickness of the head  112  for receiving the end  102   a  of the spring  102 . The head  112  also includes a drive surface  112   b  for receiving a driver head. For example, the drive surface  112   b  may be configured to have a slot for receiving a screwdriver blade and/or a hexagonal recess for receiving a hex key or Allen wrench, or other driver configuration. The perimeter of the head  112  includes a plurality of spaced apart projections  112   c  ( FIG. 6 ) arranged and configured to seat into the recesses  48  ( FIG. 10 ) of the bore  40  of the mount  26  to maintain a desired tension of the spring  102 , and to permit adjustment of the tension of the spring  102 . 
     The number of the recesses  48  preferably exceeds the number of the projections  112   c  such that the index pin  110  may be incrementally positioned from one position to another. For example, as shown, the head  112  includes four of the projections  112   c , while the bore  40  includes eight of the recesses  48 . Thus, the index pin  110  may be incrementally rotated as little as one-eighth of a turn during adjustment of the index pin  110  to tension or untension the spring  112  of the hinge  16 , as explained more fully below. If desired, the projections  112   c  and the recesses  48  may be configured to enable even smaller adjustment increments. 
     A pair of washers  118  and  120  receive the pin  110  and center it within the mounts  28 ,  66 , and  68 . The washers  118  and  120  are positioned to interface between the mounts  28 ,  66 , and  68  to provide a smooth pivot surface to facilitate pivotal movement of the swing arm  14  relative to the base plate  12 . A compression spring  122  is positioned within the mount  68  around the pin  110  adjacent the grooved end  114 , with the compression spring  122  and the c-clip  116  seated in the stepped opening  96  of the mount  68  when the hinge  16  is assembled. 
     In the assembled state of the hinge system  10 , the hinge  16  is supported by the mounts  26  and  28  of the base plate  12  and the mounts  66  and  68  of the swing arm  14 , and the tension of the spring  102  controls the self-closing (or self-opening) characteristics of the hinge  10 . The spring  102  is located so that the pin  110  passes through the coils of the spring  102 , and the end  102   a  of the spring  102  is held in the aperture  112   a  of the head  112  of the pin  110  and the end  102   b  of the spring  102  is fixed in the notch  88  of the mount  66 . The head  112  of the pin  110  is seated in the bore  40  so that the projections  112   c  of the head  112  of the pin are seated into the recesses  48  of the bore  40  of the mount  26 , with the head  112  flush with the end  42  of the mount  26 . The projections  112   c  of the head  112  as seated in the recesses  48  prevent the head from rotating and thus maintains the tension of the spring  102 , with the end  102   a  of the spring  102  captured in the aperture  112   a  of the head  112  and the end  102   b  of the spring  102  captured in the notch  88  of the mount  66 . The compression spring  122  bears against the end  94  of the mount  68  and the c-clip  116  fixed to the grooved end  114  of the pin  110 . The compression spring  122  thus urges the head  112  to remain seated in the end  42  of the mount  26 , with travel of the head  112  toward the end  44  of the mount  26  limited by the length of the recesses  48 . 
     To adjust the tension of the spring  102 , the head  112  may be released from engagement with the recesses  48  and rotated clockwise to increase spring tension, or counterclockwise to decrease spring tension, and the head  112  reseated in the recesses  48  to fix the adjusted tension. For example, with reference to  FIG. 14 , there are shown example steps for adjustment of the tension of the spring  102 . 
     In a first step, a head H of a driver D, such as an Allen wrench is engaged with the drive surface  112   b  of the head  112  of the index pin  110 . Then, force is exerted on the grooved end  114  of the pin  110  to compress the compression spring  122  and urge the head  112  out of engagement with the mount  26 , while maintaining pressure on the driver D to prevent rotation of the head  112 . The driver D may be used to rotate the head  112  in a counter-clockwise direction to wind or increase tension of the spring  102 , or in a clockwise direction to unwind or decrease tension of the spring  102 . When tension is adjusted as desired, pressure is released from the grooved end  114  of the pin  110  and the head  112  is re-seated in mount  26  with the projections  112   c  of the head  112  seated in the recesses  48  to maintain the adjusted spring tension. 
     In regard to tightening or loosening of the spring  102 , in either case, the adjustment of the index pin  110  by turning the head  112  should be limited to no more than about one-quarter of a turn. For the configuration of the head  112  and the bore  40  with the recesses  48  as noted above, one-quarter turn would correspond to one of the projections  112   c  moving into one of the recesses  48  located two away from the starting recess  48 . It is preferred that indicium or indicia, such as plus (+) and minus (−) symbols be provided on the exterior of the mount  26  to indicate which direction to rotate the head  112  to tighten or loosen the spring  102 . 
     To disable the self-closing or self-opening feature of the hinge system  10 , the above described procedure is accomplished, except that the head  112  is turned one full turn from the fully tensioned position to substantially untension to the spring. To re-engage the self-closing feature, the procedure is reversed and the head  112  is turned one full turn form the disabled position to return the spring to the fully tensioned state. If desired, the tension may then be reduced as described above. 
     As will be appreciated, the described hinge system  10  advantageously provides a butterfly hinge system configured to have an adjustable closing (or opening) tension. 
     The foregoing description of preferred embodiments for this disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the disclosure and its practical application, and to thereby enable one of ordinary skill in the art to utilize the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.