Abstract:
A fly tying bobbin for holding a spool of thread and guiding thread supplied from the spool includes a flat sided holding portion, a pair of opposed spool holding arms and a pair of opposed spool bearing elements. The holding portion is adapted to be held between the thumb and forefinger and to orient the bobbin. The opposed spool holding arms extend from respective attachment points on the holding portion. The attachment points are spaced from each other and define a first axis parallel to the sides. The pair of opposed spool bearing elements are positioned at respective free ends of the pair of spool bearing arms. The spool bearing elements are engagable with respective end surfaces of the spool to rotatably support the spool. The spool bearing elements define a second axis passing therethrough about which the spool is rotatable. The second axis and the first axis are substantially perpendicular.

Description:
FIELD 
     The present invention relates to an ergonomic bobbin used to hold a spool of thread and to feed the thread while tying artificial fishing flies. 
     BACKGROUND 
     Fly tying bobbins are used to a hold a spool of thread or other material (e.g., floss), and to feed and manipulate the thread under sufficient tension while tying flies. 
     A conventional bobbin as used heretofore has a frame with pair of opposing arms that rotatably support a spool of thread. The arms are joined at a holding portion. A guide tube that extends from the holding portion receives thread from the spool and allows the user to guide the thread, e.g., in winding the thread onto a hook shank. The conventional bobbin is configured such that one of the end surfaces of the spool contacts the user&#39;s palm when the bobbin is held. 
     It is an object of the invention to provide a bobbin construction that provides the same or greater functionality than conventional bobbins, yet is more convenient and comfortable to use. 
     SUMMARY 
     According to the invention, a fly tying bobbin for holding a conventional thread spool and guiding thread supplied from the spool includes a holding portion adapted to be held between a user&#39;s thumb and forefinger during use of the bobbin, thereby orienting the bobbin. A pair of opposed spool holding arms extend from the holding portion, and opposed spool bearing elements are positioned at respective free ends of the spool holding arms, the spool holding arms being so formed that the cylindrical surface of a spool rather than an end of the spool contacts the user&#39;s palm. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a conventional fly tying bobbin showing the bobbin being held during use. 
     FIG. 2 is a perspective view of a bobbin according to the invention showing the bobbin being held during use. 
     FIG. 3 is perspective view of the bobbin of FIG.  2 . 
     FIG. 4 is a top view of the bobbin of FIG.  2 . 
     FIG. 5 is a top view of the bobbin of FIG. 2, except without a spool of thread. 
     FIG. 6 is a side view of the bobbin of FIG.  5 . 
     FIG. 7 is a partial sectional view of the holding portion of the bobbin of FIG.  5 . 
     FIG. 8 is an end view of the bobbin of FIG.  5 . 
    
    
     DETAILED DESCRIPTION 
     As illustrated in FIG. 1, a conventional bobbin  100  has a frame  102  for rotatably supporting a spool  104  of thread  106 . The thread  106  is fed from the spool  104  through a hollow guide tube  108 . During use of the bobbin  100 , e.g., in wrapping the shank of a fish hook (not shown), the thread  106  is pulled from a working end of the guide tube  108 . As the thread  106  is pulled, the spool  104  rotates and additional thread  106  is fed. 
     The frame  102  has a holding portion  110  comprising an elliptical tube adapted to be held between the thumb and forefinger of a user, and a pair of opposed spool holding arms  112 ,  114  that lie in a plane parallel to the flattened sides of the holding portion  110 . The spool holding arms  112 ,  114  extend from the holding portion  110  and have respective spool bearing members  116 ,  118  attached at their free ends. The spool bearing members  116 ,  118  engage holes in the opposite end surfaces (one being shown at  115 ) of the spool  104  defined by the axial spool hole. The spool holding arms  112 ,  114  are formed of a resilient material (typically stainless steel) and are shaped such that they must be stretched apart to accommodate the spool  104 . 
     During use, the bobbin  100  is held with the holding portion  110  between a user&#39;s thumb T and a forefinger F (e.g., as shown in FIG. 1 for a right hand H). With the conventional bobbin  100 , one of the spool holding arms  112 ,  114  and the associated end surface  115  of the spool  104  contact the user&#39;s palm during use. For some fly tyers, the action of the rotating end surface  115  and the pressure of the spool holding arm  112  against the palm of the hand H is uncomfortable, especially during periods of prolonged use of the bobbin  100 . 
     In another type of conventional bobbin (not shown) manufactured by Guidebrod, a specially designed spool is oriented to rotate on an axis parallel to the guide tube. This bobbin construction, however, cannot be used with conventional spools of thread, e.g., the spool  104 . 
     According to the invention, a new bobbin construction is provided that is more convenient and comfortable to hold and use. More specifically, the new construction permits the bobbin to be held and used such that the circumferential surface of the spool, rather than the end surface, contacts the palm. 
     A specific implementation of a new bobbin  200  according to the invention is shown in FIGS. 2-8. As shown in FIGS. 2-4, the bobbin  200  has a frame  202  with spool holding arms  212 ,  214  that extend from a holding portion  210  at points above and below, respectively, a rear portion of a guide tube  208  projecting through the holding portion  210 . The holding portion  210  has parallel, opposing flat side surfaces  211  and a hexagonal peripheral edge  213 . 
     The spool holding arms  212 ,  214  are identical to each other in configuration. The spool holding arms  212 ,  214  have free ends  228 ,  230 , respectively, to which are attached, e.g., by an adhesive, respective spool bearing elements, which, in the illustrated implementation are spheres  216 ,  218 . The spheres  216 ,  218  define respective bearing surfaces  220 ,  222  that receive and rotatably support the spool  104  by engaging in the opposite ends of the axial spool hole. As the bobbin  200  is shown in FIGS. 6 and 7, the spool holding arm  212  that extends from the holding portion  210  above the guide tube  208  includes a first section  232  fixed in the holding portion and that extends parallel to the guide tube  208  and a second section  236  that projects angularly downward. Similarly, the spool holding arm  214  that extends from the holding portion  210  below the guide tube  208  includes a first section  234  fixed in the holding position and that extends parallel to the guide tube  208  and a second section  238  that projects angularly upward. 
     The second section  236  of the spool holding arm  212  is joined at an elbow  224  to an angularly upward projecting third section  240 , which terminates in the free end  228 . Similarly, the second section  238  of the spool holding arm  214  is joined at an elbow  226  to an angularly downward projecting third section  242 , which terminates in the free end  230 . In this way, the spheres  216 ,  218  are positioned with their coincident axes extending substantially perpendicular to a plane parallel to the holding portion side surfaces  211 . 
     As shown most clearly in FIGS. 5 and 6, the spheres  216 ,  218  have coincident axes that are horizontally aligned along an axis d when the bobbin  200  is viewed from the side with the bobbin oriented so that the holding portion surfaces  211  are vertical. The axis d is parallel to an axis d′, which is defined by the coincident axes of the spheres  216 ,  218  with the spool  104  inserted therebetween, the axis d′ being positioned slightly leftward of the axis d toward the holding portion  210 , as the bobbin is shown in FIG.  4 . 
     As best shown in FIGS. 6 and 8, the spool holding arms  212 ,  214  are “twisted” when compared to the spool holding arms  112 ,  114  of the conventional bobbin  100 . That is, the bobbin  200  is configured such that the end surfaces  215  of the spool  104  held thereby are approximately perpendicular to the palm of the user during use of the bobbin  200 , as shown in FIG. 2, so that the cylindrical surface of the thread spool  104  engages the user&#39;s palm, as best shown in FIG.  2 . As stated, the spool holding arms  212 ,  214  are identical to each other, and are also symmetrical with respect to each other about an axis extending through the guide tube  208 . 
     Again referring to FIG. 8, the line c, which extends approximately vertically, lies in a plane defined by the axis of the guide tube  208 , the median plane of the holding portion  210 , and the axes of the fixed end sections  232 ,  234  of the spool holding arms  212 ,  214 , respectively. Thus, in the position shown, the fixed sections  232 ,  234  of the spool holding arms  212 ,  214  are vertically aligned, whereas the free ends  228 ,  230  of the spool holding arms  212 ,  214  are substantially horizontally aligned (i.e., the spheres  216 ,  218  are aligned along the axis d or the axis d′). 
     Referring to FIG. 6, the axis d is spaced by a distance l from a rearmost edge surface of the holding portion  210  (i.e., the position of the line c). For the particular configuration shown, which is dimensioned for a standard-sized spool of thread, the distance l is approximately 2{fraction (5/16)} inches. For the same configuration with the spool  104  inserted between the spool holding arms  212 ,  214 , the axis d′ is spaced by a distance l′ of approximately 2¼ inches, as shown in FIG.  4 . Of course, the bobbin can be configured to hold other sizes of spools, in which case the distances l and l′ would change accordingly. 
     The opposing flat side surfaces  211  of the holding portion  210  are sufficiently sized for a user conveniently to hold and to manipulate the bobbin  200  during use. As noted previously, the holding portion  210  is shaped as a hexagonal solid. Forward edge surfaces  248 ,  250  and rearward edge surfaces  252 ,  254  provide additional points by which the bobbin  200  can be held and manipulated (e.g., using the thumb T and/or the forefinger F) during use. 
     As shown in FIG. 7, the guide tube  208  is positioned within an aperture  244  extending through the holding portion  210 . The guide tube  208  is preferably secured in place using an epoxy adhesive or other suitable material. The guide tube  208  is positioned within the holding portion  210  such that a forward end  209   a  extends by a desired working length W from the holding portion  210 . A rearward end  209   b  of the guide tube  208  projects toward and receives the thread  106  from the spool  104 . The forward and rearward ends are both chamfered to prevent damage to the thread  106 . The guide tube  208  is preferably constructed of a ceramic material for wear resistance. 
     As also shown in FIG. 7, the fixed end  232  of the spool holding arm  212  is inserted into a bore  256  in the holding portion  210  above and parallel to the bore  244 . The fixed end  234  of the spool holding arm  214  is inserted into a bore  258  in the holding portion  210  also parallel to the bore  244 , but below the latter. The fixed ends  232 ,  234  are secured within the respective bores  256 ,  258  using any suitable means, such as, e.g., by brazing or with a suitable adhesive. 
     In operation, the spool holding arms  212 ,  214  are spread apart from their relaxed positions (FIG.  5 ), and the spool  104  is inserted therebetween with the bearing surfaces  220 ,  222  centered in the holes in the end surfaces of the spool  104 . The round periphery of each of the spheres  216 ,  218  allows the spool end surfaces to be slid laterally until the spheres  216 ,  218  engage the holes in the end surfaces. Because of the configuration of the spool holding arms  212 ,  214 , the spool  104  is positioned to rotate on an axis that is approximately perpendicular to the planes of the holding portion side surfaces  211 . A sufficient amount of thread  106  is fed from the spool  104 , through the rear guide tube end  209   b  and out the forward guide tube end  209   a.  A thread delivery direction defined by the guide tube  208  is approximately perpendicular to the rotation axis of the spool  104 . 
     In use, the free end of the thread  106  extending out of the guide tube  208  is attached to an object, e.g., a hook shank. The bobbin  200  is then held in the hand H between the thumb T and the forefinger F and the thread  106  is wound around the hook shank by rotating the bobbin  200  around the shank. Additional thread is pulled from the spool  104 , which causes the spool  104  to rotate. Because the relatively broad and flat circumferential surface of the spool  104  rests against the palm of the hand H, the rotating action of the spool  104  is not uncomfortable to the user. 
     The frame  202  of the bobbin  200  is preferably formed of stainless steel. The holding portion  210  and the spheres  216 ,  218  are preferably formed of brass. As would be known to those of ordinary skill in the art, other suitable materials could be used. While spheres are preferred for engaging in the thread spool aperture because their securement to the holding arms  212 ,  214  does not require a specific orientation of the spheres and the surfaces thereof do not present any edges to the hand, other spool engaging elements could be utilized, such as, for example, the elements  116 ,  118  of the illustrated prior art bobbin. 
     Having illustrated and described the principles of the invention with reference to a preferred embodiment, it should be apparent to those of ordinary skill in the art that the invention may be modified in arrangement and detail. I claim as my invention all such modifications that fall within the scope of the following claims.