Patent Application
20160054092
The field of the present invention relates to crossbows. In particular, a rail slide for a crossbow is disclosed herein for guiding a bowstring of the crossbow.
A crossbow comprises a longitudinal rail, first and second bow limbs, a slide, and a bowstring. The longitudinal rail has a longitudinal slot. The first and second bow limbs are coupled to the rail and arranged on opposing sides of the rail. The slide has a transverse hole therethrough. The bowstring is coupled to the first and second bow limbs and passes through the transverse hole through the slide. The slide is engaged with the slot so as to be constrained to move reciprocally along the rail and so as to enable the bowstring to move (i) from a forward brace position to a rearward drawn position and (ii) from the rearward drawn position to the forward brace position. A forward surface of the slide can be structurally adapted to engage a rear end of a bolt loaded onto the rail of the crossbow.
A method for using the crossbow comprises: (a) drawing the crossbow by pulling the bowstring from the forward brace position to the rearward drawn position; (b) with the bowstring in the rearward drawn position, placing a bolt onto the slot; and (c) with the bowstring in the rearward drawn position and the bolt on the slot, releasing the bowstring, thereby (i) enabling the bowstring to move from the rearward drawn position to the forward brace position and (ii) propelling the bolt from the crossbow. A method for making the crossbow comprises: (a) engaging the slide with the slot; (b) passing a bowstring through the transverse hole through the slide; and (c) coupling the bowstring to the first and second bow limbs.
Objects and advantages pertaining to a crossbow rail slide may become apparent upon referring to the example embodiments illustrated in the drawings and disclosed in the following written description or appended claims.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
It should be noted that the embodiments depicted are shown only schematically, and that not all features may be shown in full detail or in proper proportion. Certain features or structures may be exaggerated relative to others for clarity. It should be noted further that the embodiments shown are examples only, and should not be construed as limiting the scope of the present disclosure or appended claims.
For purposes of the present disclosure and appended claims, the following definitions shall be employed. “Longitudinal” shall designate a direction generally parallel to the direction in which a bolt is launched from the crossbow; “transverse” shall designate any direction generally perpendicular to the direction in which the bolt is launched. A longitudinal cross section is defined by a plane that is parallel to the longitudinal direction and is viewed along a transverse direction; a transverse cross section is defined by a plane that is perpendicular to the longitudinal direction and is viewed along the longitudinal direction. “Forward” shall designate the longitudinal direction in which the launched bolt travels (i.e., away from the archer using the crossbow); “rearward” or “backward” shall designate the opposite longitudinal direction (i.e., toward the archer using the crossbow).
An example of a crossbow 10 is illustrated schematically in
A bowstring 150 is coupled to the bow limbs 110a/110b. In
The bowstring 150 can be coupled to the limbs 110a/110b in any suitable way. In the examples of
The rail 120 includes a longitudinal slot 130 along at least a substantial portion of its length. When a bolt 200 is loaded onto the crossbow 100, it is placed onto the slot 130, which holds the bolt 200 on the rail 120 and guides the bolt 200 as it is launched from the crossbow 100 when the crossbow 100 is shot. The slot 130 can optionally include beveled or chamfered edges (e.g., beveled edges shown in the examples of
A slide 140 is engaged with the slot 130 so as to be constrained to move reciprocally along the rail 120. A portion of the slide 140 extending through the slot 130 provides lateral constraint; a portion of the slide 140 engaging edges or the interior of the slot 130 provides vertical constraint (e.g., to prevent the slide from lifting off from the rail 120). A first example of the slide 140 is illustrated schematically in
In the examples shown in the drawings, the transverse hole 144 is somewhat vertically elongated so as to accommodate any loops, servings, or other enlarged portions of the bowstring 150, thereby facilitating passage of the bowstring 150 through the hole 144 during stringing of the crossbow 100. In some other examples (not shown), the transverse hole 144 might be only just large enough to accommodate the bowstring 150; in those examples some loops or servings on the bowstring 150 would need to be formed after passing the bowstring 150 through the hole 144. The hole 144 can be positioned as close as practicable to the rearward end of the slide 140 so as to reduce potential interference with any bowstring retaining member(s) of the crossbow trigger mechanism (not shown). The longitudinal and transverse dimensions of the slide 140 are can be made as small as practicable for the same reason, and also to limit the mass of the slide 140.
In the example of
While the general desirability of shorter slide 140 is noted above, the slide 140 must also be sufficiently long to enable it to remain engaged with the slot 130 when the crossbow 100 is shot. If the slide is too short, the slide 140 has been observed to fail structurally (i.e., break apart) when the crossbow 100 is shot. The minimum practicable length of the slide 140 can vary depending on a number of factors including one or more of: tensile, compressive, or shear strength of the one or more materials constituting the slide 140; tolerance of the engagement of the slide 140 with the slot 130 and the resulting permitted pitching motion of the slide 140 relative to the rail 120; the coefficient of friction of the slide 140 moving along the slot 130; the mass of the bolt 200; or the draw weight of the crossbow 100. For a given set of values of those parameters, a minimum length of the slide 140 can be empirically determined that results in acceptably infrequent structural failure of the slide 140. In one specific example (an acetal slide 140 on an aluminum rail 120), a slide 140 about 0.5 inches long was observed to be sufficiently long to avoid structural failure when used with a crossbow having a speed of about 350 feet/second (using a 390 grain bolt).
A forward surface of the slide 140 is structurally adapted to engage a rear end of the bolt 200 that is loaded onto the rail 120 of the crossbow 100. While the general desirability of smaller slide 140 is noted above, the slide 140 preferably has transverse dimensions sufficiently large to engage at least a substantial portion of the cross sectional area of the rear end of the bolt 200 and to maintain that engagement when the crossbow is shot and the bolt 200 is propelled form the crossbow 100. In the simplest example arrangement (
The examples shown in the drawings include a second transverse passage 146. Passage 146 can be optionally included to reduce the mass of the slide. The mass of the slide correspondingly decreases the kinetic energy imparted to the bolt 200 when the crossbow is shot; reduction of that mass is generally desirable. Any suitable holes, bores, passages, relief slots, and so forth can be employed to reduce the mass of the slide 140, provided the strength or structural integrity of the slide 140 is not unduly compromised.
Instead of reducing the mass of slide 140, the mass can be purposefully increased to mitigate the effects of a so-called dry firing or dry loosing of the crossbow (i.e., shooting the drawn crossbow without loading a bolt; this frequently results in significant damage to the crossbow or injury to the user). Increased mass of the slide 140 dissipates some of the energy of a dry fire and can reduce the likelihood of damage or injury, at the expense of reduced kinetic energy imparted to the bolt 200 when the crossbow 100 is shot properly loaded with the bolt 200. In one specific example, a slide 140 of about 35 grains (i.e., about 2.2 grams) was observed to be sufficiently heavy to avoid damage or injury when used with a crossbow having a speed of about 350 feet/second (using a 390 grain bolt).
Any suitable strong, rigid one or more materials can be used to form the slide 140. One criterion for choosing one or more materials for the slide 140 can be sufficiently low friction with the material of the rail 120 (i.e., high lubricity); another selection criterion can be sufficient resistance to wear. If low mass is desired, then low density can be another criterion; conversely, if high mass is desired, then high density can be another criterion. Polymer or composite materials (e.g., fiber-reinforced polymer) are often suitable choices for slide 140 when the rail 120 is metal; metal can be a suitable choice for slide 140 if the rail is polymer or composite. Some specific examples of materials for the slide 140 can include, e.g., MDS nylon (molybdenum disulfide filled nylon), Delrin® (polyoxymethylene a/k/a acetal), glass-filled Teflon® (polytetrafluoroethylene and glass fibers), or ultra-high-molecular-weight polyethylene. Any other suitable one or more materials can be employed.
In addition to the preceding, the following examples fall within the scope of the present disclosure or appended claims:
A crossbow comprising: (a) a longitudinal rail having a longitudinal slot; (b) first and second bow limbs coupled to the rail and arranged on opposing sides of the rail; (c) a slide having a transverse hole therethrough; and (d) a bowstring coupled to the first and second bow limbs and passing through the transverse hole through the slide, (e) wherein the slide is engaged with the slot so as to be constrained to move reciprocally along the rail and so as to enable the bowstring to move (i) from a forward brace position to a rearward drawn position and (ii) from the rearward drawn position to the forward brace position.
A method for using a crossbow, the method comprising:
(a) drawing the crossbow by pulling a bowstring of the crossbow from a forward brace position to a rearward drawn position; (b) with the bowstring held in the rearward drawn position, placing a bolt onto a longitudinal slot of a longitudinal rail of the crossbow; and (c) with the bowstring in the rearward drawn position and the bolt on the slot, releasing the bowstring, thereby (i) enabling the bowstring to move from the rearward drawn position to the forward brace position and (ii) propelling the bolt from the crossbow, (d) wherein the crossbow comprises: (i) the longitudinal rail having the longitudinal slot; (ii) first and second bow limbs coupled to the rail and arranged on opposing sides of the rail; (iii) a slide having a transverse hole therethrough; and (iv) the bowstring, said bowstring being coupled to the first and second bow limbs and passing through the transverse hole through the slide, and (e) wherein the slide is engaged with the slot so as to be constrained to move reciprocally along the rail and so as to enable the bowstring to move (i) from the forward brace position to the rearward drawn position and (ii) from the rearward drawn position to the forward brace position.
A method for making a crossbow, the method comprising:
(a) engaging a slide with a longitudinal slot of a longitudinal rail of the crossbow; (b) passing a bowstring through a transverse hole through the slide; and (c) coupling the bowstring to first and second bow limbs, said bow limbs being coupled to the rail and arranged on opposing sides of the rail, (d) wherein the slide is engaged with the slot so as to be constrained to move reciprocally along the rail and so as to enable the bowstring to move from a forward brace position to a rearward drawn position and from the rearward drawn position to the forward brace position.
The crossbow or method of any one of Examples 1 through 3 wherein the crossbow further comprises a transverse riser substantially rigidly attached to a forward portion of the rail, and the first and second limbs are attached to respective first and second lateral portions of the riser on opposite sides of the rail.
The crossbow or method of any one of Examples 1 through 4 wherein the slide is sufficiently heavy so as to substantially prevent damage to the crossbow or injury to a user of the crossbow when the bowstring is released from the rearward drawn position without a/the bolt on the rail.
The crossbow or method of any one of Examples 1 through 5 wherein the slide is sufficiently long so as to substantially prevent structural failure of the slide when the bowstring is released from the rearward drawn position.
The crossbow or method of any one of Examples 1 through 6 wherein a forward surface of the slide is structurally adapted to engage a rear end of a bolt loaded onto the rail of the crossbow.
The crossbow or method of Example 7 wherein the forward surface of the slide is substantially flat.
The crossbow or method of Example 7 wherein the forward surface of the slide includes a rearwardly extending recessed cavity arranged to receive therein the rear end of the bolt loaded onto the rail of the crossbow.
The crossbow or method of Example 7 wherein the forward surface of the slide includes a protruding horizontal ridge structurally arranged to engage a bowstring groove of a nock at the rear end of the bolt loaded onto the rail of the crossbow.
The crossbow or method of any one of Examples 1 through 10 wherein one or both of the slide or the slot are structurally arranged so as to substantially prevent lift off of the slide from the rail.
The crossbow or method of Example 11 wherein the slide has a transverse cross section that includes a dovetailed portion structurally arranged to engage the slot and constrain the slide to move reciprocally along the rail.
The crossbow or method of Example 11 wherein the slide has a transverse cross section that includes an inverted T-shaped portion structurally arranged to engage the slot and constrain the slide to move reciprocally along the rail.
It is intended that equivalents of the disclosed example embodiments and methods shall fall within the scope of the present disclosure or appended claims. It is intended that the disclosed example embodiments and methods, and equivalents thereof, may be modified while remaining within the scope of the present disclosure or appended claims.
In the foregoing Detailed Description, various features may be grouped together in several example embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that any claimed embodiment requires more features than are expressly recited in the corresponding claim. Rather, as the appended claims reflect, inventive subject matter may lie in less than all features of a single disclosed example embodiment. Thus, the appended claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate disclosed embodiment. However, the present disclosure shall also be construed as implicitly disclosing any embodiment having any suitable set of one or more disclosed or claimed features (i.e., a set of features that are neither incompatible nor mutually exclusive) that appear in the present disclosure or the appended claims, including those sets that may not be explicitly disclosed herein. It should be further noted that the scope of the appended claims does not necessarily encompass the whole of the subject matter disclosed herein.
For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “a dog or a cat” would be interpreted as “a dog, or a cat, or both”; e.g., “a dog, a cat, or a mouse” would be interpreted as “a dog, or a cat, or a mouse, or any two, or all three”), unless: (i) it is explicitly stated otherwise, e.g., by use of “either . . . or,” “only one of,” or similar language; or (ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives. For purposes of the present disclosure and appended claims, the words “comprising,” “including,” “having,” and variants thereof, wherever they appear, shall be construed as open ended terminology, with the same meaning as if the phrase “at least” were appended after each instance thereof, unless explicitly stated otherwise.
In the appended claims, if the provisions of 35 USC §112 ¶6 are desired to be invoked in an apparatus claim, then the word “means” will appear in that apparatus claim. If those provisions are desired to be invoked in a method claim, the words “a step for” will appear in that method claim. Conversely, if the words “means” or “a step for” do not appear in a claim, then the provisions of 35 USC §112 ¶6 are not intended to be invoked for that claim.
If any one or more disclosures are incorporated herein by reference and such incorporated disclosures conflict in part or whole with, or differ in scope from, the present disclosure, then to the extent of conflict, broader disclosure, or broader definition of terms, the present disclosure controls. If such incorporated disclosures conflict in part or whole with one another, then to the extent of conflict, the later-dated disclosure controls.
The Abstract is provided as required as an aid to those searching for specific subject matter within the patent literature. However, the Abstract is not intended to imply that any elements, features, or limitations recited therein are necessarily encompassed by any particular claim. The scope of subject matter encompassed by each claim shall be determined by the recitation of only that claim.
