The disclosure relates to a crossbow with a crossing cable system with power cables crossing the centerline of the stock.
In earlier crossbows, the timing power cables crossing the centerline of the flight track had to be deflected in a downward direction to pass under the flight track. The offset loads from the cables would tend to deflect the limbs in the direction of the offset, causing “out of plane” travel of the arrow or bolt when the draw string is pulled to the full draw position and released to propel the arrow or bolt.
In some embodiments, the present disclosure addresses these problems by providing for a crossing cable system that is oriented lower on a cable take-up journal attached to the underside of the cam to minimize the offset loads from the timing cables crossing the centerline of the flight track. In some embodiments, the present disclosure uses a smaller cam string profile than previous crossbows via rotating cam assemblies mounted to brackets that are fixed to the riser. In one embodiment, the cams and the limbs are in different vertically spaced horizontal planes, and the power cables are aligned in the same horizontal plane as the limbs. In some embodiments, the cable take-up journal may be attached to the upperside of the cam to minimize the offset loads from the timing cables crossing the centerline of the flight track.
Because the cams may be positioned on (i.e., detachably mounted to) the mounting brackets and therefore not positioned on the limbs, the present disclosure operates without the adverse effects due to the offset loads from the cable system of traditional crossbow systems. The present disclosure provides a crossbow configuration that provides minimal or substantially no deflection of the cables resulting in less friction, while aligning the draw string with the flight line of the crossbow.
In some embodiments, the cam assemblies of the present disclosure can provide for less than 270 degree or greater than 270 degree rotation with the cable system that crosses the centerline of the flight track. The crossing cable system of the present disclosure allows the cam assemblies to work together to provide enhanced cam timing as compared to conventional systems that use an “ipsilateral cable system,” which forces each cam to work independently of the other opposing cam.
With reference to the figures where like elements have been given like numerical designation to facilitate an understanding of the disclosure, and particularly with reference to the embodiment of the disclosure illustrated in
Crossbow 100 may have a stock 102 that may be elongated along a centerline 101 from a distal end 116 to a proximal end 118. A riser 108 may be attached to the distal end 116 of the crossbow. The riser 108 may extend on both sides (left side 120 and right side 122) of the centerline 101 of the stock 102. Limbs 106a and 106b may respectively attach to left and right sides of riser 108 on the top and at bottom sides of the riser 108, such as at attachment points 136a and 136b via screws or other fastening means. Limbs 106a and 106b may be solid limbs or split limbs, as readily understood by skilled artisans.
Limbs 106a and 106b may have concave bend, be elongated, and extend from the attachment points 136a, 136b toward the proximal end 118. In some cases, the distal end of the limbs 106 may be spatially closer to the centerline 101 than the proximal end of the limbs 106.
The riser 108 may attach to the limbs 106a, 106b at junction points 166a, 166b, 168a, 168b with upper caps 152a, 152b and with lower caps 154a, 154b (
Upper mounting brackets 107a and 107b may be attached at respective attachment points 140a, 140b to the riser 108. The upper mounting brackets 107a, 107b may include a central sloping portion and be elongated and may extend from the attachment points 140a, 140b toward the proximal end 118, such that the proximal end of the mounting brackets 107a, 107b may be non-coplanar with a distal end of the brackets 107a, 107b. The proximal end of the mounting brackets 107a, 107b may be attached respectively to cam assemblies 104a, 104b at attachment points 138a, 138b where axles 139a, 139b may located.
Lower mounting brackets 124a, 124b (
In some embodiments, the upper mounting brackets 107a and 107b and/or the lower mounting brackets 124a, 124b may be integrally formed with the riser 108. For example, the brackets 107 and/or 124 may be integrally formed with the riser 108 as a single piece. In some embodiments, the brackets 107 and/or 124 may be mounted to the flight track (i.e., to the stock 102, as shown in
Cam assemblies 104a, 104b may have a first portion, which may be a generally circular-shaped cam body, and a second portion, which may be a power cable take-up assembly 126. Cam assemblies 104a, 104b may rotate about axles 139a, 139b. In some embodiments, cam assemblies 104a, 104b may rotate less than 270 degrees about the axles 139a, 139b. For example, cam assemblies 104a, 104b may rotate about 259 degrees when the crossbow 100/string 112 is transitioning from a brace or non-drawn position to a fully drawn position (see
The top side of cam assemblies 104a, 104b may include cam-draw string attachment points 150a, 150b, which both may attach to ends of the draw string 112. The middle portion of draw string 112 may wrap around the cam assemblies 104 in cam draw string guides 148a, 148b. The draw string 112 may cross the centerline 101 above the stock 102 (i.e., flight track), as shown in
As shown in
Timing power cables 110a, 110b may respectively attach to cams 104b, 104a and to limbs 106a, 106b, providing a crossing (e.g., traversing centerline 101) of the timing power cables 110a, 110b in and through the stock 102. For example, cable 110a may attach to cam 104b and to limb 106a, and cable 110b may attach to cam 104a and to limb 106b. One end of cable 110b may attach to the proximal end of limb 106b at an attachment point 134b. The other end of cable 110b may attach to the bottom side of cam 104a at attachment point 170a. The cable 110b may wrap around a power cable take-up assembly 126a extending down in the form of a hub on the bottom side of cam 104a (
One end of cable 110a may attach to the proximal end of limb 106a at an attachment point 134b. The other end of cable 110a may attach to the bottom side of cam 104b at attachment point 170b. The cable 110a may wrap around a power cable take-up assembly 126b extending down on the bottom side of cam 104b. The cable 110a may wrap around a helical take-up journal 146b on the outer surface of the take-up assembly 126b.
Cables 110a, 110b may cross (e.g., traverse centerline 101) through a cable stabilizer assembly 129 located within a cable crossing aperture 128 extending from the left side 120 to the right side 122 within and through the stock 102. In some embodiments, cables 110a, 110b may traverse centerline 101 inside the stock 102. In some embodiments, cables 110a, 110b may traverse centerline 101 below or above the stock 102. In some embodiments, cables 110a, 110b may cross inside the stock 102. In some embodiments, cables 110a, 110b may cross below or above the stock 102. Cable stabilizer assembly 129 may include two channels, one for each cable 110a, 110b to pass through. Aperture 128 may be located under the upper rail track 131 and above center rails 130 in a central stock opening 132 of the stock 102. The cables 110a, 110b are non-coplanar with the draw string 112. The crossing of the cables 110 acts to minimize the offset loads and deflection of the cables 110 crossing the centerline 101 of the track 131.
Because a user might not pull an arrow directly in the center of the flight track each and every time, and because the limbs of a crossbow might not be perfectly matched, the accuracy of a shot arrow may decrease, as in conventional systems. The present embodiments address this with the crossing closed loop system presently disclosed. That is, the fixing of the cams 104 on the mounting brackets 107 and 124 prevents getting feedback from the opposing limb and keeps the crossbow and cables in time.
Cam 104 may also include a borehole 506a that forms an axle 139a when attached to the mounting brackets 107 and 124 via a bolt or other attachment means through 506a. Cam 104 may rotate around the axle 139a via movement or drawing of the draw string 112. On the bottom side 508 of the cam 104, the power cable take-up assembly 126 extends from the center of main body portion of the cam 104 down away from the main body portion of the cam 104. Take-up assembly 126 may include one or more helical journals 146 that wrap around the outer surface of the assembly 126, forming a helical pattern.
The bottom side 508 may include attachment point 170a. Power cable 110b may wrap around the helical journals 146 and attach at the attachment point 170a. As shown, there may be three helical journals 146, such that power cable 110b may wrap around about three full turns or about 1080 degrees when the draw string 112 is fully drawn. For example, the cams 104 may rotate up to about three full turns or about 1080 degrees as the drawstring 112 rotates the cams 104, thereby wrapping the power cables 110 around the assembly 126, and reverse for when the draw string 112 is released or not drawn (e.g., after firing the crossbow 100). According to some aspects, the length of the string 112 may limit the number of rotations the power cables 110 rotate around the journals 146 in the assembly 126. That is, the rotation is dictated by the length of string 112 wrapped around the string guide 148. Once the string 112 is in full draw position, no more of string 112 can be unwrapped from string guide 148, thus preventing the cam 104 and assembly 126 from rotating any further past this full draw position. In some embodiments, there may be more than three journals 146 or less than three journals 146, such as shown in
As the cam 104a rotates when the crossbow 100 is drawn and cocked, the slack of the power cable 110b is taken up in the journals 146. For example, when the crossbow 100 is not cocked and the draw string 112 has yet to be drawn back toward the proximal end 118, the cable 110b may occupy the top two journals 146. In one example, as the crossbow 100 is cocked and the draw string 112 is pulled back toward the proximal end 118, the cam 104a rotates 360 degrees and facilitates the movement of cable 110b down the assembly 126 such that the cable 110 occupies all three journals 146. In such an example, each 360 degree turn of the cam 104a may rotate the cable 110a down or up one journal 146. The cam profile and size may correspond to the number of journals 146 and to the vertical distance between journals 146 on the assembly 126. In some embodiments, the cam 104a may rotate more than 340 degrees, such as when the cam profile is smaller. In some cases, the journals 146 may be vertically spaced closer together on the assembly 126, which may be referred to as a “tight helical” cable journal configuration, such as shown in
In one embodiment of the assembly 126 having three journals, the upper journal 146 may be about ½ to ⅝ inches down from the circular body portion of the cam 104a. In one embodiment, the middle journal 146 may be about ⅝ to ¾ inches down from the circular body portion of the cam 104a. In one embodiment, the lower journal 148 may be about ¾ inches to 1 inch down from the circular body portion of the cam 104a. In this sense, when the crossbow 100 is at full draw, there may be a vertical distance of about ⅝ to about ¾ inches (or even 1 inch) between the draw string 112 and cable 104 on the lower journal 146, and the cable 104 may align in the same plane with the limb 106, such as aligning in substantially the same plane (e.g., horizontal plane) as connection point 134.
As the cables 104 moves up and down on the assembly 126, the angle of the cables 104 relative to a horizontal plane increases and decreases. For example, this angle may be in the range of about 0-2 degrees (e.g., at full draw) with a horizontal plane (e.g., one parallel to the ground, or one going through the cam body of cam 104/draw string guide 148) to about 4-6 degrees when the crossbow 100 is in a non-cocked configuration.
Riser 108 may include a cavity 714 and groove 716, which may facilitate the drawing and firing of an arrow or bolt placed within the groove 716. Riser 108 may attach to the stock 102 via the connection projections 713 and connection cutout 715, such as via bolts, screens, or other fastening means. The connection cutout 715 may include a borehole 718 for connecting to stock 102. Projection 713 and cutout 715 may be reciprocally shaped as the distal end of the stock 102, such that projections 713 may fit inside of the distal end of the stock 102 and an extension from the stock 102 may fit into the connection cutout 715.
While preferred embodiments of the present disclosure have been described, it is to be understood that the embodiments described are illustrative only and that the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalents, many variations and modifications naturally occurring to those skilled in the art from a perusal hereof
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/847,434, filed on May 14, 2019, which is incorporated in its entirety by reference herein.
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Number | Date | Country | |
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62847434 | May 2019 | US |