Abstract:
The sight mounted to a bow portion for archery, which includes an elevation bar fixed to the bow portion and having a first sliding surface and a second sliding surface; a box mounted so as to be slidable along the first sliding surface and the second sliding surface of the elevation bar; an elastic member mounted to the box so as to be opposed to the first sliding surface; and a pressurizing device that pressurizes the elastic member in a direction at an angle with respect to the first sliding surface to deform the elastic member, the box being pressurized by the first sliding surface due to the elastic member and pressed against the second sliding surface. By the archery sight, it can solve the problem that a rattling is generated and leads to poor reproduction performance, resulting in rather poor usability for the athlete.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/599,057 filed Aug. 6, 2004. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sight used as an archery equipment (hereinafter referred to as a “sight”). 
     2. Related Background Art 
     As shown in  FIG. 1 , a bow  1  for use in archery is composed of a bow portion  1  and a string  2 . The bow portion  1  is an arcuate plate-like member, to the ends of which the ends of the string  2  are respectively attached. When the string  2  is drawn, the distance between the ends of the bow portion  1  is reduced, and the bow rim is deflected. The deflection of the bow portion  1  causes elastic energy for shooting out an arrow to be accumulated in the bow portion  1 . The string  2  transmits the elastic energy accumulated in the bow portion  1  to the arrow. 
     Further, a stabilizer  3  and a sight  4  are mounted to the bow portion  1  so as to extend forwards from the bow portion  1  respectively. The stabilizer  3  is mounted for the purpose of stabilizing the attitude of the bow and mitigating vibration, impact, etc. The sight  4  is mounted for the purpose of aiming the arrow to the target. 
     The sight  4  is a device which relates the line of sight of an athlete, the attitude of the bow portion  1  held by the athlete, and the target P. As shown in  FIGS. 2A and 2B , the sight  4  has an elevation bar  11 , a box  12 , and a sight pin  6 . The elevation bar  11  is fixed by means of a mounting shaft  5  extending forwards from the bow portion  1  such that the elevation bar  11  is positioned substantially along the vertical direction when shooting is performed with the bow portion  1  upright. 
     The box  12  is mounted to the elevation bar  11  so as to be slidable along the elevation bar  11 . Arranged on the elevation bar  11  is a feed screw  13  elongated in the axial direction of the elevation bar  11 . The feed screw  13  is threadedly engaged with the box  12  so that the box  12  can make fine movement along the elevation bar  11  through rotation of the feed screw  13 . 
     The sight pin  6  is mounted to the box  12 . The sight pin  6  is formed as a thin and narrow cylinder with a small circular section, and is mounted to the box  12  such that the axis of the pin is substantially aligned with the line connecting the eyes of the athlete and the target P when shooting is performed with the bow portion  1  upright. As shown in  FIG. 1 , in this condition, the athlete firmly holds the bow portion  1  such that the small circular section of the sight pin  6  is aimed at the target P, whereby it is always possible for the athlete to hold the bow portion  1  in the same condition. 
     In reality, however, the bow portion  1  cannot always be held perfectly in the same condition in the strict sense. Further, even if the bow portion  1  is held perfectly in the same condition in the strict sense, it can happen that, when the athlete shoots with the sight pin  6  of the sight  4  aimed at the target P, the arrow is off the mark depending upon the physical condition of the athlete, the weather, etc. In such cases, the box  12  is moved along the elevation bar  11  in accordance with the deviation amount to shift the position of the sight pin  6  and correct the previous shooting condition of the athlete. The athlete senses a difference between the shooting the target P with the sight pin  6  at the initial position and the shooting the target P with the position of the sight pin  6  shifted, and thereby can refer to it as information for correction for the next shooting. 
     In this way, the sight  4 , which is a device used as a reference for the athlete when performing shooting next, is required to always exhibit highly accurate positional reproducibility. In particular, due to vibration or the like caused by the deformation of the bow portion  1 , the box  12  is likely to be displaced with respect to the elevation bar  11 . However, in the conventional sight  4 , in which the box  12  is caused to slide along the elevation bar  11 , it is necessary to perform dimensional processing on the box  12  and the elevation bar  11 , with a gap for processing being maintained between the box  12  and the elevator bar  11 . Further, in this processing, a dimensional tolerance is naturally required. As a result, between the box  12  and the elevation bar  11 , in each dimension, there exists a gap caused by a tolerance required. This gap leads to rattling of the box  12  with respect to the elevation bar  11 , and by extension, to a positional error of the box  12  with respect to the elevation bar  11 . Such rattling is generated in both the horizontal and the vertical directions of the sections of the box  12  and the elevation bar  11 . That is, though needed in terms of processing, this gap leads to rather poor reproduction performance for an archery-sight, resulting in rather poor usability for the athlete. 
     SUMMARY OF THE INVENTION 
     The purpose of the invention is provided to solve the above-mentioned problems. 
     Another purpose of the invention is to provide an archery sight mounted to a bow portion for archery, including: an elevation bar fixed to the bow portion and having a first sliding surface and a second sliding surface; a box mounted so as to be slidable along the first sliding surface and the second sliding surface of the elevation bar; an elastic member mounted to the box so as to be opposed to the first sliding surface; and a pressurizing means that pressurizes the elastic member in a direction at an angle with respect to the first sliding surface to deform the elastic member, the box being pressurized by the first sliding surface due to the elastic member and pressed against the second sliding surface. 
     Due to the above construction, it is possible to move the box while involving no play between itself and the elevation bar, with load being applied to the elevation bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a general view of an archery bow; 
         FIG. 2A  is a side view of an archery-sight according to the present invention; 
         FIG. 2B  is a front view of the archery-sight according to the present invention; 
         FIG. 3  is a sectional view of a sight according to a first embodiment of the present invention, mainly showing the box and the elevation bar thereof; 
         FIG. 4  is a schematic view of the sight according to the first embodiment of the present invention, showing the relationship between a first sliding surface, a pressure screw, and a pressure plate; 
         FIG. 5  is a sectional view of the sight according to the first embodiment of the present invention, showing in detail the load directions in the portion where the box and the elevation bar exist; 
         FIG. 6  is a diagram showing an example of a sight according to a second embodiment of the present invention; and 
         FIG. 7  is a diagram showing another example of the sight according to the second embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     (Embodiment 1) 
     The embodiment 1 of the present invention will be described with reference to  FIGS. 1 through 4 . 
     As shown in  FIG. 1 , the archery bow  1  has the bow portion  1  and the string  2 . The operations of the bow portion  1  and the string  2  are as described above. The stabilizer  3  and the sight  4  are further mounted to the bow portion  1  so as to extend forwards from the bow portion  1 . The operations of the stabilizer  3  and the sight  4  are also as described above. As shown in  FIGS. 2A and 2B , the sight  4  includes an elevation bar  11 , an box  12 , and a sight pin  6 . The elevation bar  11  is fixed with regard to the bow portion  1  by means of the extension  5  extending forwards so as to be substantially in the vertical position when a person shoots a bow with vertically positioning the bow portion  1 . 
     As shown in  FIGS. 2A and 2B , the box  12  is mounted to the elevation bar  11  so as to be capable of sliding along the elevation bar  11 . Arranged on the elevation bar  11  is the feed screw  13  elongated in the axial direction of the elevation bar  11 . The feed screw  13  is threadedly engaged with the box  12 , enabling the box  12  to make fine movement along the elevation bar  11  through rotation of the feed screw  13 . The sight pin  6  is mounted to the box  12 . The function of the sight pin  6  is also the same as described above. 
     Subsequently, the portions featuring the present invention will be described with reference to  FIGS. 2A ,  2 B, and  3  through  5 .  FIG. 3  is a sectional view taken along the line  3 — 3  of  FIG. 2A . 
     The box  12  has is mounted to the elevation bar  11  so as to be slidable along the same. For example, the box  12  has a sectional configuration enclosing the elevation bar  11 . 
     At the center of the elevation bar  11 , there is arranged the feed screw  13  so as to extend in the sliding direction of the box  12 , which corresponds to the longitudinal direction of the elevation bar  11 . Preferably, the feed screw  13  is arranged substantially at the center of the elevation bar  11   
     The elevation bar  11  has a first sliding surface  20  and a fourth sliding surface  23  provided with an angle with respect to the first sliding surface. For example, the first and fourth sliding surfaces on the box  12  are provided on the main body side of the elevation bar  11 . Respectively mounted to the portions of the box  12  corresponding to the first sliding surface  20  and the fourth sliding surface  23  are pressure plates  14  and  15 , which are elastic members. The pressure plates  14  and  15  are formed of an elastic resin, typical examples of which include polyamide resin and polyacetal resin. 
     The pressure plates  14  and  15  are respectively arranged so as to be opposed to the first and fourth sliding surfaces  20  and  23 , which means each of them has substantially the same angle as the first and fourth sliding surfaces  20  and  23 . 
     Each of the pressure plates  14  and  15  is mounted to the box  12 , with their both ends being fixed thereto. The box  12  is equipped with holes having screw portions each at an angle with respect to the pressure plates  14  and  15 . Presser screws  30  and  31  as pressurizing means are respectively threadedly engaged with the holes having the screw holes. A plurality of holes having screw portions are arranged in the longitudinal direction of each of the pressure plates  14  and  15 . Further, plural screws are threadedly engaged so as to be respectively in correspondence with the holes. 
       FIG. 4  shows the positional and operational relationship between the pressure plate  14 , the first sliding surface  20 , and the plurality of pressure screws  30  and  32  threadedly engaged with the holes having screw portions formed so as to be at an angle with respect to the pressure plate  14 . While the drawing only shows the relationship between the pressure plate  14 , the first sliding surface  20 , and the pressure screws  30  and  32 , the same applies to the relationship between the pressure plate  15 , the fourth sliding surface  23 , and the pressure screw  31 , which are in plane symmetry therewith. 
     As shown in the drawing, the pressure plate  14  has at its ends tab portions  14   a  and  14   b  for mounting. The pressure plate  14  is fixed in position such that the tab portions  14   a  and  14   b  enter the end portions of the box  12 . Thus, the pressure plate  14  is in a plate-beam-like state with their both ends fixed. Between the tab portions  14   a  and  14   b  at the ends of the pressure plate  14 , there are arranged the pressure screws  30  and  32  serving as the pressurizing means. Although not shown in  FIG. 4 , the box  12  has holes having screw portions formed so as to be at an angle with respect to the pressure plate  14 , and the pressure screws  30  and  32  are threadedly engaged with these holes as described above. 
     With the pressure plate  14  being fixed to the box  12  by means of the tab portions  14   a  and  14   b , the lower surface of the pressure plate  14  is adjusted so as to constitute a surface  14   c  which is in contact with the first sliding surface  20  while being substantially parallel thereto. The positions of the end portions of the pressure screws  30  and  32  are adjusted such that, in the initial state, their forward ends abut the upper surface of the pressure plate  14 , which is in contact with the first sliding surface  20 . When they are further tightened, the pressure screws  30  and  32  go ahead along the holes by thread provided in the respective holes, until the forward ends of the pressure screws  30  and  32  protrude on the other side. The respective protruding forward ends of the pressure screws  30  and  32  gives pressure to the surface of the pressure plate  14  and deforms he pressure plate  14  so as to be shifted from the position of the surface  14   c  to the first sliding surface  20 , which is in contact with the first sliding surface  20  while being substantially parallel thereto, to a defected position  14   d , where it pressurizes the first sliding surface  20 . That is, as a result of the respective forward end portions of the pressure screws  30  and  32  protruding, the pressure screws  30  and  32  as pressurizing means pressurizes the surface of the pressure plate  14  as the elastic member against the first sliding surface  20  with deforming the elastic member. 
       FIG. 5  schematically shows the relationship between the elevation bar  11  and the box  12  of  FIG. 3 . In the following, the relationship will be described in more detail with reference to  FIGS. 3 and 5 . 
     A second sliding surface  21  is arranged on the elevation bar  11  on the same side as the first sliding surface  20  as well as on the side opposite to the box  12 , and a fifth sliding surface  24  is arranged on the elevation bar  11  on the same side as the fourth sliding surface  23  as well as on the side opposite to the box  12 . 
     On the box  12  side, there are arranged at respective positions opposed to the second sliding surface  21  and the fifth sliding surface  24 , receiving portions  22  and  25  constituting other elastic members. It is desirable for the receiving portions  22  and  25  to be formed of an elastic resin respectively. Typical examples of the resin include polyamide resin and polyacetal resin. 
     In this construction, when the surface of the pressure plate  14  deformed through pressurization due to the protrusion of the forward end portions of the pressure screws  30  and  32  pressurizes the box  12  through the intermediation of the first sliding surface  20 , the box  12  is inclined to move in the pressurizing direction. At the same time, the forward end portions of the pressure screws  31  and  33  protrude, whereby the pressure plate  15  is pressurized to be deformed, and the deformed surface of the pressure plate  15  is pressed against the box  12  through the intermediation of the fourth sliding surface  23 . As a result, there is no more clearance (gap) between the first sliding surface  20  and the pressure plate  14  and between the fourth sliding surface  23  and the pressure plate  15 , respectively. 
     The first sliding surface  20  and the fourth sliding surface  23  provided with an angle to the first sliding surface  20  are respectively arranged on the box. The pressure plates  14  and  15  fixed thereto are also arranged at an angle, so that, as indicated by the arrows in  FIG. 5 , the pressurization by the pressure screws  30  and  31  presses the box against the sides respectively opposed to the pressure screws  30  and  31 , that is, against the receiving portions  17  and  16 , respectively. 
     Conversely, when viewed in terms of the horizontal and vertical components of the pressurization force by the pressure screws  30  and  31 , arranged as shown in  FIG. 5 , the box  12  is to be pressed against the elevation bar  11  in both the horizontal and the vertical directions. As a result, due to the pressurization by the pressure screws  30  and  31 , the pressure plates  14  and  15  are deformed to pressurize the first sliding surface  20  and the fourth sliding surface  23 , and due to this pressurization exerted on the first sliding surface  20  and the fourth sliding surface  23 , the elevation bar  11  makes a relative movement away from the box  12 . Further, as a result, the second sliding surface  21  and the fifth sliding surface  24 , arranged on the elevation bar  11  on the opposite sides of the first sliding surface  20  and the fourth sliding surface  23 , are respectively pressurized so as to bring them into contact with the third sliding surface  22  and the sixth sliding surface  25  of the receiving portion  16 . As a result, there is no more play between the second sliding surface  21  and the third sliding surface  22 . Similarly, there is no more clearance between the fifth sliding surface  24  and the sixth sliding surface  25 . 
     Pressurization is exerted in the horizontal direction in  FIG. 5 , with the first sliding surface  20  and the fourth sliding surface  23  being opposed to each other, so that the box  12  is fixed to the elevation bar  11  also in the horizontal direction. 
     Here, it is desirable for the first sliding surface  20  and the second sliding surface  21  to be parallel to each other. Further, it is also desirable for the fourth sliding surface  23  and the fifth sliding surface  24  to be parallel to each other. As will be illustrated with referent, for example, to the relationship between the pressure screw  30 , the pressure plate  14 , the first sliding surface  20 , and the second sliding surface  21 , of the pressurizing force of the pressure screw  30  causing deformation of the pressure plate  14 , the vertical force component thereof as seen in  FIG. 5  is transmitted to the first sliding surface  20 , and at the same time, is transmitted more efficiently to the second sliding surface  21 , which is substantially parallel to the first sliding surface  20 . 
     In this way, by the screws serving as the pressurizing means, the box  12  is substantially fixed to the elevation bar  11 , with practically no play left in the horizontal direction nor the vertical direction in the section thereof. It should be noted, however, that the pressure plates  14  and  15  and the receiving portions  16  and  17  are formed of elastic chemical resin, so that, even in the state in which the pressure plates  14  and  15  are deformed by the pressure screws  30 ,  31 ,  32 , and  33  respectively serving as the pressurizing means and pressed against the first sliding surface  20 , that is, even in the state in which fixation is substantially effected with practically no play in the horizontal direction nor the vertical direction, the box  12  can slide in the axial direction, which is the longitudinal direction of the elevation bar  11 , along the first sliding surface  20  while involving no play. 
     That is, although due to the pressure plates  14  and  15  and the receiving portions  16  and  17  there is no gap between the box  12  and the elevation bar  11 , and the box  12  is fixed in both the horizontal direction and the vertical direction in the section of the box  12  and the elevation bar  11 , the box  12  can slide along the elevation bar  11 . This helps to enhance the positional reproducibility of the sight pin  6  mounted to the box  12  with respect to the elevation bar  11 . 
     It should be noted that, through adjustment of the amount by which the pressure screws  30  and  32  protrude, it is possible to adjust the force with which the pressure plate  14  pressurizes the first sliding surface  20 . This makes it possible to adjust the frictional force between the pressure plate  14  and the first sliding surface  20 , making it possible to adjust the manner in which the box  12  moves relative to the elevation bar  11 . This also applies to the relationship between the pressure screws  31  and  33  and the pressure plate  15 . 
     (Second Embodiment) 
     As described in the first embodiment, according to the present invention, there are mounted the pressure plates  14  and  15  consisting of elastic members at the portions of the box  12  respectively corresponding to the two surfaces; the first sliding surface  20  and the fourth sliding surface  23  arranged at an angle with respect to the first sliding surface  20 , whereby the box  12  can move along the elevation bar  11  while fixed in both the horizontal direction and the vertical direction. 
     However, as shown in  FIG. 6  or  7 , the same effect can also be achieved with a single set of components consisting of the first sliding surface  20 , the pressure plate  14 , and the pressure screw  30 . In this case, the second sliding surface  21  is arranged on the surface of the elevation bar facing in the pressurizing direction of the pressure screw  30 , opposed to the box  12  on the opposite side of the first sliding surface  20 . And, the third sliding surface  22  is arranged on the portion of the box  12  corresponding to the second sliding surface  21 . The third sliding surface  22  is formed of elastic resin. In this case, as shown in  FIG. 6 , a groove is provided in the box  12 , with the third sliding surface  22  constituting a part of this groove. On the other hand, the elevation bar  11  has a protrusion with a sectional configuration corresponding to this groove, with the second sliding surface  21  constituting a part of this protrusion. Thus, even when the groove and the protrusion are engaged with each other and pressurization is effected from one direction, the effect is the same as that when fixation is effected in both the horizontal direction and the vertical direction in  FIG. 6 , with the box  12  being enabled to move along the elevation bar  11 . 
     Further, while in the example shown in  FIG. 6  the box  12  has a groove and the elevation bar  11  has a protrusion with a sectional configuration corresponding to the groove, this relationship may be reversed, as shown in  FIG. 7 . 
     That is, in the case of  FIG. 7 , the box  12  is equipped with a protrusion, and the third sliding surface  22  constitutes a part of this protrusion. On the other hand, the elevation bar  11  has a groove with a sectional configuration corresponding to this protrusion, with the second sliding surface  21  constituting a part of this groove. Thus, even when the groove and the protrusion are engaged with each other, and pressurization is effected from one direction, the same effect as that in the case of  FIG. 6  is obtained.