WO2021194387A1

WO2021194387A1 - Crossbow with vertical arrangement of limbs and cams

Info

Publication number: WO2021194387A1
Application number: PCT/RU2021/050021
Authority: WO
Inventors: Sergey Olegovich Popov
Original assignee: Sergey Olegovich Popov
Priority date: 2020-03-23
Filing date: 2021-01-29
Publication date: 2021-09-30
Also published as: RU2730798C1

Abstract

The present invention relates to devices for throwing arrows, in particular to crossbows. The crossbow consists of a frame 1 having a frame plane. A first cam (2) and a second cam (3) are arranged on the frame, which have respective rotation axes, the frame also comprising peripheral surfaces for arranging a bowstring (9) and peripheral surfaces for arranging at least one cable (10), (11). The cams (2), (3) are rotatably mounted on respective holders in planes that lie substantially in parallel to the frame plane on two opposite sides thereof. The frame plane is perpendicular to the rotation axes of the first cam and the second cam. Also, the crossbow has at least one limb (4), (5), which first end is secured to the frame (1), and which second end is configured to move in such a way that, when the crossbow is used, said at least one limb (4), (5) bends in a limb plane substantially parallel to the frame plane. At least one cable (10), (11) connects the second end of the at least one limb (4), (5) and the cams (2), (3). The technical effect consists in reduction in crossbow dimensions both in width and in height, while maintaining its specifications.

Description

CROSSBOW WITH VERTICAL ARRANGEMENT OF LIMBS AND CAMS

The present invention relates to devices for throwing arrows, in particular to crossbows.

Many varieties of crossbows are known, wherein a limb arrangement and bending plane, a cam arrangement plane, a cable passing plane, and a bowstring plane are parallel to each other or coincide, and, when making a shot with a crossbow, these planes are positioned horizontally and substantially perpendicular to a vertical plane of a crossbow frame. A crossbow structure, wherein limbs and cams are positioned in a horizontal plane, is most widely spread, the crossbow according to Patent US 9297604 (publ. 29.03.2016) may be cited as an example. Parallelism or coincidence of limb arrangement and bending planes, cam arrangement and cable passing planes as well as a bowstring plane leads to increasing transverse dimensions of a crossbow, which are defined, mainly, by a limb span. A decrease in a limb span leads to the necessity of using highly elastic limbs for maintaining a high initial speed of an arrow. This creates certain difficulties while using a crossbow as well as a higher load both on components of a crossbow itself and on a shooter, since, in such a case, more effort should be applied for making a shot.

Crossbows with a limb and cam arrangement in a vertical plane are known. These crossbows have a rather small width, but this is achieved through a significant increase in their dimensions in a vertical direction, namely by arranging their limbs, cams, bowstring and cables in a vertical plane. Examples may be crossbows according to Patents US 8622050 (publ. 07.01.2014) and US 8671923 (publ. 18.03.2014), wherein limbs with cams installed thereon are arranged in a vertical plane (i.e. in a crossbow frame plane) in such a way that the first limb is arranged below the frame, and the second limb is arranged above the frame. A bowstring and cables connect the cams in a vertical plane also. The cables traverse the crossbow frame, thus creating a friction node which reduces an arrow initial speed while shooting. When being drawn, a bowstring moves along a crossbow frame in a vertical plane. Obviously, this arrangement of limbs decreases crossbow dimensions in width, but significantly increases them in height. Furthermore, a bowstring movement in a vertical plane creates inconvenience during placing an arrow as well as during aiming.

Thus, all crossbows known in the art with a vertical arrangement of limbs, cams and a bowstring pulling plane do not have advantages in dimensions in comparison with crossbows having a conventional, horizontal arrangement of limbs and cams, and, consequently, exhibit all disadvantages peculiar to crossbows with a conventional arrangement of limbs.

The objective of this invention is to develop a crossbow that will ensure a sufficient range and accuracy of a shot, easy use of such a crossbow as well as the same high initial speed of an arrow as a conventional crossbow, but will have compact dimensions at the same time.

The technical effect of the claimed invention is concurrent reduction in crossbow dimensions both in width and in height, while its technical specifications are maintained.

The above objective is reached, and the claimed technical effect is achieved due to the fact that the crossbow comprises a frame having a frame plane which positional peculiarities will be discussed in detail below. A first cam and a second cam, which have respective rotation axes, are arranged on the frame that is also provided with peripheral surfaces for positioning a bowstring and peripheral surfaces for positioning at least one cable. The first cam and the second cam are rotatably mounted on respective holders in planes that lie substantially parallel to the frame plane on two opposite sides of the frame plane, the frame plane being perpendicular to the rotation axes of the first cam and the second cam. Further, the crossbow has at least one limb that, in its turn, has a first limb end secured to the frame and a second limb end configured to move in such a way that, when the crossbow is used, this at least one limb bends in the limb plane substantially parallel to the frame plane. The crossbow comprises a bowstring connecting the first cam and the second cam, and at least one cable connecting the second end of at least one limb and these cams.

The claimed crossbow structure is characterized by compact dimensions due to the fact that, firstly, the plane of the crossbow frame, the planes of the first cam and the second cam, and the plane (or planes) of said at least one limb (i.e. the movement plane (or planes) of the second, free end of said at least one limb) are substantially parallel to each other. Secondly, as distinct from known analogous solutions, the plane of the first cam and the plane of the second cam do not coincide, but lie on different sides of the crossbow frame plane. This generally enables using only one limb instead of two compulsory limbs according to analogs, which contributes to making the crossbow structure not only more compact, but also easier and simpler.

In order to connect the cams with the frame, cam holders made of a rigid material may be used. As an alternative, the same material that is used for making the limbs can be used for making them, i.e. a material that can deform elastically. These cam holders may be arranged substantially along the crossbow frame, on two opposite sides thereof, and may move or not move during cocking the crossbow; and, further, the cam holders may be made either as parts integral with the crossbow frame, or parts separate from the crossbow frame, or may be made as a single piece.

Also, the above objective is reached, and the technical effect is achieved in and by particular embodiments of the claimed crossbow with vertical arrangement of limbs and cams.

Thus, the crossbow may be made so as the axes of the first cam and the second cam coincide, i.e., lie on one straight line.

The crossbow may further comprise a first bowstring stabilizer and a second bowstring stabilizer, which are arranged on two opposite sides of the crossbow frame. The bowstring stabilizers are intended for directing the bowstring more accurately while cocking the crossbow, which is conditioned by arranging the first cam and the second cam in different planes. The bowstring stabilizers may be made as a single piece, or as two parts separate from the frame, or as parts integral with the frame. The bowstring connects the first cam and the second cam by passing through these bowstring stabilizers in a horizontal plane (relative to a vertical plane of the frame). A structure of the bowstring stabilizers may be either simple, or complex. For example, rollers with a cone-shaped peripheral track may be used as the bowstring stabilizers, said rollers will be mounted on two sides of the frame and will be configured to rotate in a horizontal perpendicular plane relative to the frame plane.

In one embodiment of the crossbow, a second end of at least one limb is directed substantially in the direction of an arrow movement. In another embodiment, a second end of at least one limb is directed substantially opposite to the direction of an arrow movement.

Moreover, a second end of at least one limb of a crossbow may be positioned substantially above an axis of an arrow movement or below the axis of an arrow movement.

Below, the invention is described in more detail with reference to the drawings, wherein:

Fig. la shows a top view of an embodiment of a crossbow with two limbs arranged mainly below the crossbow frame;

Fig. lb shows a side view of an embodiment of a crossbow with two limbs arranged mainly below the crossbow frame;

Fig. 2a shows a top view of an embodiment of a crossbow with two limbs arranged mainly above the crossbow frame;

Fig. 2b shows a side view of an embodiment of a crossbow with two limbs arranged mainly above the crossbow frame. It should be noted that illustrations of a crossbow, as shown in Figs la, lb, 2a, 2b, with exemplary arrangements of its limbs, cams, bowstring, bowstring stabilizers, and cable are provided for the purpose of understanding this invention in general, and may differ, more or less, in both construction of the respective crossbow components and their position.

According to this invention, the crossbow comprises a frame 1 having a frame plane. For the purposes of this invention, the crossbow frame plane is understood as a plane coinciding with the plane depicted in Figs lb and 2b. Correspondingly, the crossbow frame plane is essentially a vertical plane that is perpendicular to the plane depicted in Figs la and 2a.

A first cam 2 and a second cam 3 as well as at least one limb are secured to the frame 1. As an example, Figs la and 2a illustrate embodiments of a crossbow with two limbs, namely, a first limb 4 and a second limb 5, though, as a person skilled in the art may appreciate, for implementing this invention and achieving the stated technical effect the crossbow may have only one limb.

The first cam 2 and the second cam 3 are positioned, each, in a vertical plane, i.e. the planes, wherein the cams 2, 3 are positioned, are substantially parallel to the plane of the frame 1, the plane of the first cam 2 being on one side of the plane of the frame 1, and the plane of the second cam 3 being on the other side of the plane of the frame 1.

In order to connect the cams 2, 3 with the frame 1, cam holders made of a rigid material may be used. As an alternative, for example, the same material as used for making the limbs may be used for making them, i.e. an elastic material providing the cam holders with the capability of deforming elastically. The rigid material is understood here as a material which use for making a cam holder does not cause a noticeable change in a cam holder shape when a crossbow is used in a conventional way. The elastic material is understood here as a material which use for making a cam holder causes a change in a cam holder shape when a crossbow is used in a conventional way, e.g. it causes a bending of a cam holder when a bowstring is drawn.

The cam holders may be arranged substantially along the frame 1, on two opposite sides of the frame 1, and may move or not move when cocking the crossbow. Further, the holders of the cams 2, 3 may be made either as parts integral with the frame 1, or parts separate from the frame 1, or may be made as a single piece. The first cam 2 and the second cam 3 rotate around their respective rotation axes. Figs lb and 2b show a rotation axis 6 of the first cam 2. And a rotation axis of the second cam 3 may lie substantially on the same straight line as the rotation axis 6 lies.

First ends of the limbs 4, 5 are connected to the frame 1, and second ends of the limbs 4, 5 are made free and capable of moving in planes substantially parallel to the plane of the frame 1, or planes of the respective limbs. When two limbs, namely the first limb 4 and the second limb 5, are used, a plane of the first cam 2 and a plane of the first limb 4 are positioned substantially vertically, i.e. parallel to the plane of the frame 1 on its one side, and a plane of the second cam 3 and a plane of the second limb 5 are positioned on the opposite side of the frame 1, but also vertically, i.e. parallel to the plane of the frame 1, the rotation axes of the first cam 1 and the second cam 2 being perpendicular to the plane of the frame 1 and, as said above, may lie on one straight line.

The first limb 4 and the second limb 5 in one embodiment shown in Fig. lb are secured with their first ends to the lower portion of the frame 1 in such a way that the free ends of the first limb 4 and the second limb 5 are positioned substantially below the arrow movement axis and in the direction of the arrow movement. As an alternative, these free ends of the first limb 4 and the second limb 5 may be directed substantially opposite to the direction of the arrow movement.

The first limb 4 and the second limb 5 in another embodiment shown in Fig. 2b are secured with their first ends to the upper portion of the frame 1 in such a way that the free ends of the first limb 4 and the second limb 5 are positioned substantially above the axis of the arrow movement and in the direction that is opposite to the direction of the arrow movement. As an alternative, these free ends of the first limb 4 and the second limb 5 may be directed substantially to the side that is opposite to the direction of the arrow movement.

The first limb 4 and the second limb 5 may be secured either directly to the frame 1, or through limb holders, as shown in Figs lb, 2b.

The first limb 4 and the second limb 5 may be made as one piece or may consist of two or more parts.

The first cam 2 and the second cam 3 are connected with a bowstring 9 that is used for imparting an initial speed to an arrow (not shown in the drawings). When the crossbow is not cocked, the bowstring 9 is positioned, mainly, on the first cam 2 and the second cam 3 on respective peripheral surfaces intended for placing the bowstring 9. These peripheral surfaces intended for placing the bowstring 9 may be either flat, or be made as grooves in the end surfaces of the cams 2, 3.

In order to direct the bowstring 9 more accurately, additional elements - bowstring stabilizers 7, 8 - may be used. A first bowstring stabilizer 7 is arranged on one side of the frame 1, and a second bowstring stabilizer 8 is arranged on the opposite side of the frame 1 relative to the frame plane; and they direct the bowstring 9 during its unwinding from and winding to the first cam 2 and the second cam 3. The bowstring stabilizer 7 and the bowstring stabilizer 8 may be made as a single part or two parts separate from the frame 1, or as one part or two parts integral with the frame 1. A structure of the bowstring stabilizers 7, 8 may be any suitable structure. For example, rollers with a cylindrical or cone-shaped peripheral track may be used as the bowstring stabilizers 7, 8, which are arranged so as to be able to rotate around vertical axes substantially parallel to the frame plane.

The free end of the first limb 4 and the first cam 2 are connected with a first cable 10. The free end of the second limb 5 and the second cam 3 are connected with a second cable 11. Different variants of securing the ends of the cables 10, 11 to the cams 2, 3 are possible. Further, different variants of connecting the cables 10, 11 with the free ends of the limbs 4, 5 are also possible. The ends of the cables 10, 11 may be secured directly to the free ends of the limbs 4, 5. Also, for example, the cables 10, 11 may be passed through rollers arranged on the free ends of the limbs 4, 5 and may be secured to the frame 1 or to other parts of the crossbow.

The connection of the cams 2, 3 with the limbs 4, 5 by the cables 10, 11 may be made irrespective of a variant of arranging the limbs 4, 5 on the frame 1 relative to the arrow movement axis as well as irrespective of a variant of arranging the free ends of the limbs 4, 5 relative to the direction of the arrow movement.

During drawing the bowstring 9, the first cam 2 and the second cam 3 are driven to rotate around their respective rotation axes, thus causing winding the cable 10 and the cable 11 onto the respective peripheral surfaces intended for placing the cables of the first cam 2 and the second cam 3. Winding of the cables 10, 11 onto the respective surfaces intended for placing the cables causes a bending of the first limb 4 and the second limb 5 and accumulation of energy therein. During releasing the bowstring 9, the first cam 2 and the second cam 3 rotate in the opposite direction, their rotation speed being defined by a speed of unbending of the first limb 4 and the second limb 5 and directly influences an initial speed of an arrow. The limbs 4, 5 may be directed relative to the frame 1 at a different angle, for example, as shown in Figs lb and 2b, i.e. at a small angle to the frame 1, which enables to make the crossbow as compact as possible. An angle of position of the limbs 4, 5 at the point of their securing to the frame 1 relative to the axis of the arrow movement (and, consequently, the axis of the frame 1) may be defined by a person skilled in the art and is conditioned not only by ensuring compactness of the crossbow, but also by specific elasticity and bending amplitude of the limbs 2, 3.

In any of the above-described embodiments of the crossbow, during drawing the bowstring 9, the limbs are directed and positioned, and, consequently, the cables 10, 11 are wound onto the first cam 2 and the second cam 3, respectively, the limbs 4, 5 are bent, and the first cam 2 and the second cam 3 rotate substantially in a vertical plane parallel to the plane of the frame 1. This makes dimensions of the crossbow minimal both in its width and its height, while the crossbow specifications, such as its weight, shot speed, etc., are not affected in any way.

A person skilled in the art will appreciate that one common cable connecting the first cam 2 and the second cam 3 may be used instead of the first cable 10 and the second cable 11 in a particular embodiment of the crossbow. A single limb may be used instead of the first limb 4 and the second limb 5. In such a case, it is preferable, though not obligatory, that a plane of said single limb substantially coincides with the frame plane. Said common cable will be passed through the free end of one limb, if a single limb is used, or through two ends, i.e. an end of the first limb 4 and an end of the second limb 5, provided the two limbs 4, 5 are used.

The use of one common cable and a single limb is preferable for simplifying the crossbow structure and automatically ensuring uniform tension of the cable between the first cam 2 and the second cam 3. In such a case, the free end of the limb (or of the two limbs 4, 5) may be provided with a hole, or at least one roller may be installed, or another suitable means for passing one common cable there through may be used that is known to a person skilled in the art.

Thus, the claimed crossbow and its embodiments are characterized by compact dimensions without sacrificing the device specifications.

Claims

1. A crossbow comprising: a frame having a frame plane; at least one limb having a first limb end secured to the frame and a second limb end configured to move in such a way that, when the crossbow is used, said at least one limb bends in a limb plane substantially parallel to the frame plane; a first cam holder and a second cam holder secured to the frame on two opposite sides of the frame plane; a first cam rotatably mounted on the first cam holder, the first cam having a rotation axis, a peripheral surface intended for a bowstring and at least one additional peripheral surface intended for at least one cable, said rotation axis of the first cam being substantially perpendicular to the frame plane; a second cam rotatably mounted on the second cam holder, the second cam having a rotation axis, a peripheral surface intended for a bowstring and at least one additional peripheral surface intended for at least one cable, said rotation axis of the second cam being substantially perpendicular to the frame plane; a bowstring connecting the first cam and the second cam; and at least one cable intended for connecting a second end of said at least one limb and said cams.

2. The crossbow of Claim 1, wherein the rotation axes of the first cam and the second cam lie substantially on one straight line.

3. The crossbow of Claim 1, further comprising a first bowstring stabilizer and a second bowstring stabilizer.

4. The crossbow of Claim 1, wherein the first cam holder and the second cam holder are made immovable during drawing the bowstring.

5. The crossbow of Claim 1, wherein the first cam holder and the second cam holder are made movable during drawing the bowstring.

6. The crossbow of Claim 1, wherein the first cam holder and the second cam holder are made as integral parts i with the frame.

7. The crossbow of Claim 1, wherein the first cam holder and the second cam holder are made as separate parts from the frame.

8. The crossbow of Claim 1, wherein the first cam holder and the second cam holder are made as a single piece.

9. The crossbow of Claim 1, wherein the second end of said at least one limb is directed substantially in the direction of an arrow movement.

10. The crossbow of Claim 1, wherein the second end of said at least one limb is directed substantially opposite to the direction of an arrow movement.

11. The crossbow of Claim 1, wherein the second end of said at least one limb is positioned substantially above an axis of an arrow movement.

12. The crossbow of Claim 1, wherein the second end of said at least one limb is positioned substantially below an axis of an arrow movement.