Abstract:
An adjustable mechanism for an archery sight is characterized by a unique elevation and tension adjustment assemblies which allow a user to quickly and easily set the sight for optimum performance. The mechanism includes an elevation base having an elevation rail and carriage assembly connected therewith for sliding movement along the base in a first direction. A windage carriage is connected with the elevation carriage for movement in a second direction, and a sight is connected with the windage carriage. A tension assembly including a unique traction wheel, yoke and cam mechanism is provided for adjusting the tension between the rail and the base, and an adjustable detent assembly is provided to stop movement of the elevation rail and carriage in selected elevation locations relative to the base.

Description:
This application claims the benefit of U.S. provisional application No. 61/906,149 filed Nov. 19, 2013. 
    
    
     BACKGROUND OF THE INVENTION 
     Sight devices such as those used in archery must be adjustable to fit the user precisely to provide maximum accuracy, particularly where the sight is used in tournaments or other competition. Sights are normally adjustable in three dimensions, with the most important adjustment being in elevation. The present invention relates to an improved elevation adjustment mechanism and tension assembly which allows quick and efficient adjustment of the sight holder relative to an archery bow. 
     BRIEF DESCRIPTION OF THE PRIOR ART 
     Many archers attempt to mount their sight approximately thirty inches from their anchor point. A sight bracket is mounted on the bow and an extension bar is connected with the mounting bracket. The extension bar generally extends horizontally when the bow is in use. An elevation bar is connected with the extension bar and is generally perpendicular relative to the elevation bar so that it extends vertically when the bow is in use. A carriage is arranged on the elevation bar and a sight is connected with the carriage. The carriage is displaced by the user along the elevation bar to precisely position the sight at the optimum position. Displacement of the carriage is usually done incrementally, which can be time consuming where more than fine tuning adjustment is required such as where different target distances are used in a tournament. Moreover, conventional adjustment mechanisms do not provide the user with the ability to adjust and lock the tension of elevation travel between the carriage and the elevation bar. 
     The Summers et al U.S. patent application Ser. No. 14/034,035 discloses an elevation adjustment mechanism for a sight in which an elongated screw is used to displace a carriage for a sight on an elevation bar connected with a bow. A pivot nut is used to connect the carriage with the screw so that the carriage may be engaged with or released from the screw. A tension system is provided to adjust the tension between the carriage and the elevation bar so that the user may adjust the freedom of movement of the carriage. 
     While the prior devices operate satisfactorily, they may be compromised by forward and backward bow forces that occur during the bow firing sequence. In addition, prior devices do not provide yardage selectable positions for the sight which can be adjusted and set by the user. 
     The present invention was developed in order to overcome these and other drawbacks of the prior adjustment devices by providing an elevation adjustment mechanism capable of adjustment of the elevation carriage and sight to desired positions and improved tension adjustment between the carriage and the elevation base. 
     SUMMARY OF THE INVENTION 
     A sight elevation assembly for a bow includes a variable tension assembly. The variable tension assembly includes a tension lever having a cam surface. A yoke is connected with the elevation assembly and the cam surface engages the yoke. Rotation of the tension lever in opposite directions displaces the yoke to increase and decrease the tension applied to the elevation assembly. The tension lever passes through an adjustment plate which controls the range of rotation of the lever to limit rotation of the lever between low and high tension positions, respectively. 
     The sight elevation assembly includes a base connected with a bow mount. A rail is slidably connected with the base for linear movement relative thereto. The tension assembly is connected between the rail and the base to vary the tension between the rail and base. A traction wheel is supported by the yoke and engages a portion of the rail so that rotation of the traction wheel displaces the rail relative to the base. The traction wheel has a knurled surface and the rail is formed of a synthetic plastic material which is imprinted by the tension wheel surface when the tension wheel is pressed against a surface of the rail by the tension assembly. 
     An elevation carriage is connected with the rail and a detent assembly is connected with the base and the elevation carriage for retaining the carriage in at least one linear position relative to the base corresponding to a desired elevation of the sight. The detent assembly includes at least one detent adjustably connected with the base and at least one housing adjustably connected with the carriage. The base includes side walls each of which contain a longitudinal slot in the upper portion thereof. The detents are arranged in the slots for sliding movement along the base. Each detent includes a screw which is operable to fix the detents in the desired position corresponding to an elevation selected by the user. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in the light of the accompanying drawing, in which: 
         FIGS. 1 and 2  are front and rear a perspective views, respectively, of an elevation adjustment assembly for a sight connected with an extension bar for mounting on a bow; 
         FIG. 3  is a detailed exploded perspective view of the elevation base and tension adjustment assembly for the elevation adjustment assembly shown in  FIG. 1 ; 
         FIG. 4  is an exploded sectional view of the tension adjustment assembly; 
         FIGS. 5A and 5B  are front plan views of the tension lever of the tension adjustment assembly in high and low pressure positions, respectively; 
         FIG. 6  is a side view of the tension lever shown in  FIGS. 5A and 5B ; 
         FIGS. 7 and 8  are front perspective and plan views, respectively, showing the tension adjustment assembly adjacent to an elevation rail of the elevation adjustment assembly of  FIG. 1 ; 
         FIG. 9  is an exploded side view showing the tension adjustment assembly and the elevation rail; 
         FIG. 10  is an exploded perspective view of the assembled elevation carriage mounted on the elevation rail and the detent system; 
         FIG. 11  is a side plan view of the assembled elevation carriage, elevation rail, elevation base and detent system; and 
         FIGS. 12 and 13  are exploded perspective views, respectively, showing the connection between the windage carriage and the elevation carriage of the elevation adjustment assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIGS. 1 and 2 , the sliding archery sight elevation adjustment mechanism is shown. The elevation adjustment mechanism  2  is connected with an extension bar  4  via screws  6  or other suitable fasteners. The extension bar is attached to a bow (not shown). In use, the extension bar generally extends horizontally and the elevation adjustment mechanism extends vertically, with the sight being adjusted for elevation along an elevation base  8 . 
     As shown more particularly in  FIG. 3 , the elevation base  8  includes in its upper surface a slot  10  and opposed channels  12  for receiving an elevation rail as will be developed below. A tension adjustment assembly is connected with the elevation base to adjust the tension between the rail and the base. The tension adjustment assembly will be described with reference to  FIGS. 3-9 . The elevation rail  14  is shown in  FIGS. 4 and 7-9 . 
     The tension adjustment assembly includes a tension lever  16  which passes through a central opening  18  in an adjustment plate  20  and into an aligned opening  22  in the lower portion of the elevation base  8 . The adjustment plate is connected with the base  8  via a screw (not shown) which passes through a slot  24  in the adjustment plate and engages a threaded opening  26  in the elevation base. The tension lever  16  includes a cam surface  28 . 
     The tension adjustment assembly also includes a yoke  30  arranged in the elevation base  8  beneath the slot  10 . The yoke contains a pair of channels  32  in the upper surface for supporting a shaft  34  of an elevation knob  36  which is used to displace the elevation rail  14  relative to the elevation base as will be described below. The shaft  34  includes a raised portion  38  which provides an interference fit with an axial opening  40  in a traction wheel  42 . The yoke channels  32  support the portions of the shaft  34  on opposite sides of the traction wheel  42 . 
     Referring now to  FIGS. 4 and 7-9 , the traction wheel  42  is arranged beneath the lower surface of the elevation rail  14 . The elevation rail is formed of a synthetic plastic material such as Delrin® material which is rigid but also deformable or imprintable. The traction wheel has a knurled surface  44  (best shown in  FIG. 3 ) which abuts against the lower surface of the elevation rail. Through use, the knurls or projections of the traction wheel form an embedded pattern on the elevation rail lower surface. The elevation rail  14  includes projections  46  on either side which are received in the channels  12  of the elevation base  8  when the rail is arranged in the slot  10  in the top of the base. The rail  14  is linearly displaced relative to the elevation base  8  by the user rotating the elevation knob  36  to in turn rotate the traction wheel  42 . Rotation of the knob in opposite directions slides the elevation rail within the slot in the elevation base. 
     The tension adjustment assembly increases or decreases the force applied by the traction wheel  42  against the elevation rail  14 , thereby varying the tension between the rail and the base  8  in accordance with the user&#39;s preference. Rotation of the tension lever  16  in opposite directions rotates the cam surface  28 , which abuts against the bottom of the yoke as shown in  FIG. 6 , to raise and lower the yoke which in turn raises and lowers the shaft  34  of the elevation knob  36 , thus raising and lowering the traction wheel  42 . The range of rotation of the tension lever is limited by a projection  48  on the adjustment plate  20 . In  FIG. 5A , the tension lever has been rotated clockwise until it abuts the projection in a position where the cam raises the yoke and applies the highest pressure of the traction wheel against the rail, effectively acting as a stop and preventing movement of the rail. In  FIG. 5B , the tension lever has been rotated counter clockwise until it abuts the projection in a position where the cam lowers the yoke and the minimal pressure is applied by the traction wheel against the rail. 
     Through use, the traction wheel  42  creates an impression in the lower surface of the elevation rail that provides a repeated tracking relationship that remains consistent when turning the elevation knob  36  in opposite directions. After wear from use over an extended period of time, the adjustment plate  20  can be adjusted relative to the elevation base to allow the tension lever to be rotated farther in the clockwise direction to press the traction wheel even further into the lower surface of the rail renewing an impression or footprint in the rail for greater traction and quality of operation. 
     Referring now to  FIG. 10 , the elevation rail  14  is shown connected with the elevation base  8 . As set forth above, the rail slides relative to the base within a slot in the top of the base. In order to prevent the rail from sliding out of the slot and separating from the base, the rail includes a projection  49  on either side which extends above the top surface of the base. The base top surface includes ramps or stops  50  at each end. The ramps engage the projection on the rail to prevent the rail from extending beyond either end of the slot in the base. 
     Also shown in  FIG. 10  is an elevation carriage  52  which is connected with the top of the elevation rail  14 . Thus, the elevation carriage moves with the rail relative to the base. 
     In addition to the ramps or stops  50  which limit the linear displacement of the rail at the ends of the base slot, an adjustable stop assembly is provided which can be set by the user to stop the elevation rail and carriage at selected locations relative to the elevation base. The stop assembly includes at least one detent  54  and at least one housing  56  which contains a spring biased ball. The housing is connected with one of a plurality of openings  58  in the sides of the elevation carriage by a screw  60  or other suitable fastener. A housing may be provided on both sides of the elevation carriage, if desired. The detent is connected with the side of the elevation base. As shown in  FIGS. 10 and 11 , the sides of the elevation base contain slots or channels  62  which are configured to receive the detent  54 . A screw such as a set screw  64  passes through an opening in the detent and engages an inner wall which defines the slot. Tightening of the screw locks the detent in the selected position which corresponds to a desired elevation of the sight as determined by the user. The detent can be repositioned by loosening the set screw and sliding the detent to a new elevation position and then re-tightening the set screw. Preferably, a plurality of detents are provided so that multiple elevations can be set by the user. 
     As noted above, each housing  56  contains a ball  66  and a spring  68  which are shown in  FIG. 12 , the spring biasing the ball toward an extended position. As the elevation rail and elevation carriage are displaced relative to the elevation base by rotation of the elevation knob and the traction wheel, the ball in the housing under the force of the spring engages a detent to stop the movement of the rail in the selected position. The spring force is not so great that the rail can not be moved to another elevation position as set by the user. The ball and detent stop assembly is sufficient however to position the elevation carriage and sight in the selected elevation location. 
       FIGS. 12 and 13  illustrate the connection of a windage carriage  70  to the elevation carriage. The windage carriage provides adjustment of the sight in a direction normal to the elevation adjustment of the carriage relative to the elevation base. 
     The windage carriage  70  includes two recesses (not shown) in the central bottom region of the carriage. The recesses receive two synthetic plastic ball bearings  72 . The bearings are preferably formed of Delrin® material. The windage  70  and elevation  52  carriages are configured to mate via dovetails on the elevation carriage. A screw  72  passes through a washer  74  and through aligned openings  76  and  78  in the windage carriage and elevation carriage, respectively. The opening  76  in the windage carriage is threaded whereas the openings in the elevation carriage are not. Thus, rotation of the screw displaces the windage carriage along the screw relative to the elevation carriage. 
     In order for the user to manually rotate the screw  74 , a knob  80  is connected with the free end of the screw opposite the head end thereof. A spring  82  and steel ball  84  are arranged between the knob  80  and the windage carriage. A washer  86  is arranged on the free end of the screw to which the knob is attached. A synthetic plastic ball (not shown) is arranged in a tapped hole in a side surface of the knob and held in place by a set screw  88 . Rotation of the knob  80  incrementally displaces the windage carriage along the screw relative to the elevation carriage. 
     A unique feature of the connection of the windage carriage and the elevation carriage is the use of a contoured or wavy windage gib  90  between the windage carriage and the dovetail portion of the elevation carriage as shown in  FIG. 30 . The upper surface of the windage gib contains a recess  90   a  intermediate the ends of the gib. When the windage gib is slid into the gap between the dovetail portion of the elevation carriage and the windage carriage, the gib is held in place by a retainer screw  92  which passes into a threaded opening in the windage carriage. The windage gib is formed of a resilient material such as Delrin® AF material which is a synthetic plastic material. The spring activation of the windage gib allows for the Delrin® AF material tensile strength displacement to provide the necessary tension between the windage carriage and the elevation carriage. This eliminates the need for an adjustment screw to vary the tension. 
       FIGS. 1 and 2  show a sight  94  connected with the windage carriage via a sight mount  96 . The sight is adjustable in three dimensions: vertically by adjusting the elevation carriage relative to the elevation base; laterally by adjusting the windage carriage relative to the elevation carriage; and rotationally by adjusting the sight mount  96  relative to the windage carriage. 
     While the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those of ordinary skill in the art that various changes and modifications may be made without deviating from the inventive concepts set forth above.