Patent Application
20140261358
The present disclosure is directed to an energy storage portion for a bow with limbs having distal portions and proximal portions both coupled to a center support. The present disclosure is also directed to a pulley system in which only the draw string crosses over the center support.
Bows have been used for many years as a weapon for hunting and target shooting. More advanced bows include cams that increase the mechanical advantage associated with the draw of the bowstring. The cams are configured to yield a decrease in draw force near full draw.
For optimal bow performance, substantial synchronization of rotation of the cams is required, but often problematic to achieve in practice. Synchronization typically requires secondary strings and pulleys that control the rotation of the cams, such as disclosed in U.S. Pat. No. 7,305,979 (Yehle). These additional features increase the weight, cost and maintenance of such devices, while adding additional friction, further decreasing the potential speed of the projectile.
The present disclosure is directed to an energy storage portion for a bow with limbs having distal portions and proximal portions both coupled to a center support. The present disclosure is also directed to a pulley system in which only the draw string crosses over the center support.
One embodiment is directed to an energy storage portion for a bow including a center support having a first side and a second side. At least one first limb has both a distal portion and a proximal portion coupled to the first side of the center support. At least one second limb has both a distal portion and a proximal portion coupled to the second side of the center support. At least one first pulley is attached to the first limb at a location between the distal and the proximal portions of the first limb and at least one second pulley is attached to the second limb at a location between the distal and the proximal portions of the second limb.
The distal portions and the proximal portions of the first and second limbs can be dynamically coupled or positively coupled to the center support. In one embodiment, the distal portions or the proximal portions dynamically coupled to the center support do not contact the center support until the limbs are deformed inward toward the center support.
The distal portions and/or the proximal portions of the first and second limbs can be coupled to the center support by a rigid coupling, a pivoting coupling, a linkage coupling, a rotating coupling, a sliding coupling, an elastomeric coupling, or a combination thereof. At least one of the couplings preferably provides limb relief between the proximal portion and the distal portion of the limbs. In another embodiment, the center support provides limb relief between the proximal portion and the distal portion of the limbs.
In another embodiment, at least one of the distal portions or the proximal portions of the first and second limbs are positively coupled to the center support by rotating translation arms. The rotation of the rotating translation arms is synchronized by a synchronization assembly.
A draw string extends across the center support and around portions of the first and second pulleys. In one embodiment, the draw string includes a first end secured to the first pulley and a second end secured to the second pulley. The first and second pulleys are displaced toward the center support as the draw string is pulled to a drawn configuration. In another embodiment, the first and second ends of the draw string can be coupled to the center support.
The total displacement of the first pulley axis toward the second pulley axis as the draw string is pulled to a drawn configuration is preferably less than about 3.5 inches, or about 3.0 inches. In another embodiment, separation between the first and second axes when the draw string is in a drawn configuration is less than about 10 inches and less than about 13 inches when the draw string is in the released configuration.
In one embodiment, a first power string has a first end attached to the center support and a second end attached to the first pulley, and a second power string with a first end attached to the center support and a second end attached to the second pulley. The first and second power strings preferably do not cross over the center support from the first side to the second side.
In another embodiment, the first and second limbs each include a pair of limbs arranged in a spaced apart configuration with the first and second pulleys located between the pair of limbs, respectively. The first and second limbs can be arranged in a concave or convex configuration with respect to the center support. The first and second pulleys are preferably cams. The first and second pulleys are preferably coupled to the limbs generally at a midpoint between the distal and proximal portions.
The present disclosure is also directed to a method of configuring an energy storage portion for a bow. A distal portion and a proximal portion of at least a first limb are coupled to the first side of the center support. A distal portion and a proximal portion of at least a second limb are coupled to the second side of the center support. At least one first pulley is attached to the first limb at a location between the distal and the proximal portions of the first limb and at least one second pulley is attached to the second limb at a location between the distal and the proximal portions of the second limb.
The present disclosure is also directed to a pulley system for an energy storage portion of a bow. The pulley system includes a center support having a first side and a second side. At least one first limb has at least one of a distal portion and a proximal portion coupled to the first side of the center support, and at least one second limb has at least one of a distal portion and a proximal portion coupled to the second side of the center support. At least one first pulley is attached to the first limb and at least one second pulley is attached to the second limb. A draw string extends across the center support and around portions of the first and second pulleys. The draw string includes a first end secured to the first side of the center support and a second end secured to the second side of the center support.
The present disclosure is also directed to a pulley system for an energy storage portion of a bow including a draw string extending across the center support and around portions of the first and second pulleys. The draw string includes a first end secured to the first pulley and a second end secured to the second pulley. A first power string has a first end attached to the center support and a second end attached to the first pulley. A second power string has a first end attached to the center support and a second end attached to the second pulley, whereby the first and second power strings do not cross over the center support from the first side to the second side.
The center support 52 can be a single piece or a multi-component construction. In the illustrated embodiment, the center support 52 includes a pair of machined center rails 52A, 52B coupled together with fasteners, and a pair of finger guards 53A, 53B also attached to the center rails 52A, 52B using fasteners. The components 52, 53 are preferably constructed from a light weight metal, such as high grade aluminum. As will be discussed below, the center support 52 will include a variety of additional features, such as cut-outs and mounting holes, to accommodate other components such as a trigger mechanism, cocking mechanism, stock, arrow storage, and the like (see e.g.,
In the illustrated embodiment, limbs 64A, 66A are located on first side 58A of the center plane 60 and limbs 64B, 66B are located on the second side 58B. Proximal portions 68A, 68B (“68”) of the limbs 64A, 66A are coupled to the proximal limb mount 54A in the finger guard 53A, such as by pivot pin 70 and pivot brackets 72. Proximal portions 74A, 74B (“74”) of the limbs 64B, 66B are coupled to the proximal limb mounts 56B in the finger guard 53B by pivot pin 70 and pivot brackets 72. As illustrated in
In the illustrated embodiment, translation arms 62A, 62B (“62”) are pivotally attached to the distal limb mounts 54A, 54B in the finger guards 53A, 53B, respectively. Distal portions 76A, 76B (“76”) of the limbs 64A, 66A are coupled to the translation arm mount 78A, such as by pivot pin 70 and pivot brackets 72. Distal portions 80A, 80B (“80”) of the limbs 64B, 66B are coupled to the translation arm mount 78B by pivot pin 70 and pivot brackets 72. The distal portions 76, 80 rotate on axes 82A, 82B, (“82”) relative to the translation arm mounts 78A, 78B, respectively. The translation arms 62A, 62B rotate on axes 84A, 84B (“84”), respectively, relative to the center support 52 (see,
As used herein, “coupled” or “coupling” refers to a connection between a limb and a center support. Both positive coupling and dynamic coupling are possible. “Positively coupled” or “positive coupling” refers to a limb continuously engaged with a center support. “Dynamically coupled” or “dynamic coupling” refers to a limb engage with a center support only when a certain level of tension is applied to a draw string. The coupling can be a rigid coupling, a sliding coupling, a pivoting coupling, a linkage coupling, a rotating coupling, an elastomeric coupling, or a combination thereof.
For example, in the embodiment of
As illustrated in
Various structures for providing limb relief are discussed herein. For example, limb relief can be provided by locating pivot arms 62 between proximal portions 68, 74 of the limbs 64, 66 and the proximal limb mounts 54. In yet another embodiment, limb relief is provided by pivot arms 62 located at both the distal portions 76, 80 and the proximal portions 68, 74 of the limbs 64, 66.
In an alternate embodiment, the translation arms 62 are replaced with elastomeric members that are rigidly attached to the finger guard 53. Limb relief is achieved by elastic deformation of the elastomeric translation arms. In another embodiment, limb relief is provided by a combination of deformation and rotation of the elastomeric translation arms 62 (see e.g.,
In yet another embodiment, one or both of the distal and proximal limb mounts 54, 56 are configured as slots with an elastomeric bushing to provide the limb relief.
In yet another embodiment, limb relief is provided by the center support 52 (see e.g.,
First pulley assembly 90A is pivotally coupled to the first limbs 64A, 66A at a location between the proximal and distal portions 68, 76. Second pulley assembly 90B is pivotally coupled to the second limbs 64B, 66B at a location between the proximal and the distal portions 74, 80. As best illustrated in
As used herein, the term “pulley” is refers generically to a member rotating around an axis that is designed to support movement of a flexible member, such as a rope, string, belt, chain, and the like. Pulleys typically have a groove, channel or journal located between two flanges around at least a portion of its circumference that guides the flexible member. Pulleys can be round, such as a drum or a sheave, or non-round, such as a cam. The axis of rotation can be located concentrically or eccentrically relative to the pulley.
As best illustrated in
The geometric profiles of the draw string journals 96 and the power string journals 104 contribute to let-off at full draw. The configuration of the limbs 64, 66 and the limb relief of the limbs 64, 66 to the center support 52 also contribute to let-off. A more detailed discussion of cams suitable for use in bows is provided in U.S. Pat. No. 7,305,979 (Yehle), which is hereby incorporated by reference.
In the retracted position 134 the translation arms 62 are rotated back toward proximal end 136 of the center support, with the limbs 64, 66 in a generally concave configuration with respect to the center support 52. In the release configuration 130 distance 128 between the proximal limb mounts 56 and the translation arm mounts 78 is at a minimum and width 138 of the energy storage device 50 is at its maximum.
In the illustrated embodiment, the limb relief increases the distance 148 between the proximal limb mounts 56 and the translation arm mounts 78 to be greater than the distance 128 (see
Operation of the illustrated embodiment includes locating an arrow or bolt in groove 162 with knock engaged with the draw string 100 in location 164. Release of the draw string 100 causes the limbs 64, 66 to return to the released configuration 130, thereby launching the bolt in direction 166.
As best illustrated in
The energy storage device 50 typically includes a trigger assembly to retain the draw string 100 in the drawn configuration 140 and a stock located near the proximal end 136 of the center support 52. Most trigger assemblies include a dry fire mechanism that prevents release of the draw string 100 unless a bolt is positioned in the center support 52. Suitable trigger assemblies and stocks are disclosed in U.S. Pat. No. 8,240,299 (Kronengold et al.); U.S. Pat. No. 8,104,461 (Kempf); U.S. Pat. No. 8,033,275 (Bendar et al.); U.S. Pat. No. 8,020,543 (Maleski et al.); U.S. Pat. No. 7,836,871 (Kempf); U.S. Pat. No. 7,810,480 (Shepley et al.); U.S. Pat. No. 7,770,567 (Yehle); U.S. Pat. No. 7,743,760 (Woodland); U.S. Pat. No. 7,363,921 (Kempf); U.S. Pat. No. 7,328,693 (Kempf); U.S. Pat. No. 7,174,884 (Kempf et al.); U.S. Pat. No. 6,736,123 (Summers et al.); U.S. Pat. No. 6,425,386 (Adkins); U.S. Pat. No. 6,205,990 (Adkins); U.S. Pat. No. 5,884,614 (Darlington et al.); U.S. Pat. No. 5,649,520 (Bednar); U.S. Pat. No. 5,598,829 (Bednar); U.S. Pat. No. 5,596,976 (Waiser); U.S. Pat. No. 5,085,200 (Horton et al.); U.S. Pat. No. 4,877,008 (Troubridge); U.S. Pat. No. 4,693,228 (Simonds et al.); U.S. Pat. No. 4,479,480 (Holt); U.S. Pat. No. 4,192,281 (King); and U.S. Pat. No. 4,030,473 (Puryear), which are hereby incorporated by reference.
The center support 52′ is machined to create opening 204 that receives the cocking mechanism 200. The cocking mechanism 200 includes an elongated tube 206 pivotally attached to the center support 52′ at location 208 near the distal end 132. Arm 210 pivotally couples the elongated tube 206 to traveler 212 that slides back and forth along axis 216 in channel 214 formed in the center support 52′. The traveler 212 includes finger 218 that captures the draw string 100 to move it from the released configuration 130 to the drawn configuration 140 and into engagement with a trigger assembly (not shown). In the illustrated embodiment, the elongated tube 206 includes a conventional accessory rail 220, used to attach various accessories to the center support 52′, such as forward grips, laser sights, and the like.
The limbs 64, 66 resist movement of the elongated tube 206 back to the closed and locked configuration 202. If the user inadvertently releases the elongated tube 206 during this process, it will snap back to the fully open configuration 222 with considerable force. Ratcheting mechanism 230 prevents this outcome.
As best illustrated in
Also illustrated in
As illustrated in
Distal portions 270A, 270B (“270”) of limbs 272A, 272B (“272”) are attached to the device 260 at locations 274A, 274B (274″), respectively. The attachment at the locations 274 can employ various couplings (e.g., a rigid coupling, a pivoting coupling, a linkage coupling, a rotating coupling, a sliding coupling, an elastomeric coupling, or a combination thereof). Proximal portions 276A, 276B (“276”) of the limbs 272 are configured to engage with portions 278A, 278B (“278”) of the device 260, respectively. It is possible to reverse this configuration by locating the portions 278 at the distal end of the device 260.
When the draw string 264 is in the drawn configuration 140, the limbs 272 deform in direction 280 and the proximal portions 276 translate along portions 278 in direction 282 to provide limb relief through a sliding coupling. In one embodiment, the portions 278 have a curvilinear shape to increase let-off when the draw string 264 is in the fully drawn configuration 140.
In another embodiment, the proximal portions 276 are dynamically coupled to the portions 278 of the device 260. The proximal portions 278 are not attached to the device 260. For example, space 286 may exist between the proximal portions 276 of the limbs 272 and the portions 278 when the draw string 264 is in the released configuration 130. As the limbs 272 deformed while the draw string 264 is drawn, however, the proximal portions 276 of the limbs 272 engage with the portions 278 on the device 260 and are displaced in the direction 282, in a combination of a dynamic coupling and a sliding coupling.
In another embodiment, the proximal portions 276 are positively coupled to the portions 278 by sliding couplings 284A, 284B (“284”). One advantage of the positive couplings 284 is that when the draw string 264 is released, the proximal portions 276 are prevented from lifting off of the portions 278 on the device 260, reducing noise.
In another embodiment, the proximal portions 276 of the limbs 272 are fixedly attached to the portions 278 of the device 260 as shown. The portions 278 are constructed from an elastomeric material configured to deform as the limbs 272 are deformed in the direction 280 to provide limb relief via an elastomeric coupling.
Any of the limb relief embodiments disclosed herein may be used alone or in combination.
The convex limbs 322 deflect inward in directions 330 toward the center support 324 as the draw string (not shown) is moved to the drawing configuration. In the illustrated embodiment, limb relief is provided by translation arms 328, although any of the limb relief mechanism disclosed herein may be used.
Distal ends 360A, 360B (“360”) of limbs 362A, 362B (“362”) are attached to the distal portion 354A of the center support 352. Proximal ends 364A, 364B (“364”) of limbs 362 are attached to the proximal portion 354B of the center support 352. As the draw string (not shown) is moved to the drawing configuration 140, the limbs 362 flatten so that distance 366 between distal ends 360 and proximal ends 364 of the limbs 362 increases to provide limb relief. As the draw string is released, the displacement mechanism 356 biases the distal portion 354A toward the proximal portion 354B to the configuration shown in
In the illustrated embodiment, the power strings 390 and the draw string 388 are a single structure with ends 394 attached to the center support 392. In an alternate embodiment, the power strings 390 and the draw strings 388 can be discrete structures, such as illustrated in
Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within this disclosure. The upper and lower limits of these smaller ranges which may independently be included in the smaller ranges is also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either both of those included limits are also included in the disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the various methods and materials are now described. All patents and publications mentioned herein, including those cited in the Background of the application, are hereby incorporated by reference to disclose and described the methods and/or materials in connection with which the publications are cited.
The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.
Other embodiments are possible. Although the description above contains much specificity, these should not be construed as limiting the scope of the disclosure, but as merely providing illustrations of some of the presently preferred embodiments. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of this disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes disclosed. Thus, it is intended that the scope of at least some of the present disclosure should not be limited by the particular disclosed embodiments described above.
Thus the scope of this disclosure should be determined by the appended claims and their legal equivalents. Therefore, it will be appreciated that the scope of the present disclosure fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present disclosure, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims.
