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The present invention relates to devices for throwing arrows, in particular, to bows and crossbows.
Arrow throwing devices are known, such as bows and crossbows. For instance, U.S. Pat. No. 8,651,095 discloses the crossbow comprising the frame, the first limb and the second limb mounted on the frame so that one end of each limb is secured to the frame, and another end of each limb is the loose end. The first cam and the second cam are mounted at the loose ends of the first limb and the second limb, respectively. The first cam and the second cam are connected with the string. In addition, the first cable and the second cable are attached to the first cam and the second cam, respectively, and the other ends of the cables are connected to the projections provided on the frame. Due to the use of cams and cables, the firing speed can be increased. However, such arrangement of the first cam and the second cam at the respective loose ends of the limbs causes the increase in crossbow dimensions, because portions of the cams project beyond the bow dimensions defined by the limbs. This makes usage and transportation of the known crossbow difficult.
U.S. Pat. No. 7,047,958 discloses the bow having a complex system of cams and spools forming the integral complex system. In this device, like in the above crossbow, the elements of the complex system are arranged at the loose ends of the limbs, thus increasing bow dimensions and making usage and transportation thereof quite difficult.
It is also known the bow disclosed in U.S. Pat. No. 4,287,867, wherein the cams are used which actually work as pulleys, or spools, connecting middle portions of the limbs with one of the loose ends of the limbs. The configuration of this known device needs be more sophisticated, as shown in this patent, and requires somewhat longer limbs to provide a high arrow speed. Consequently, it looks impossible to reduce overall dimensions by exclusion of the elements affecting tension of the string because the limbs must be longer to keep arrow speed high.
Therefore, there is the need to reduce overall dimensions of the arrow throwing device while maintaining essential technical characteristics thereof, such as the firing speed of an arrow.
The present invention addresses the mentioned above problem of reduction of overall dimensions of an arrow throwing device while maintaining a high arrow speed by changing a traditional position of cams. In particular, instead of arranging the cams at loose ends of limbs it is suggested to mount the cams within an area defined by an axis of arrow travel and a corresponding loose end of the limb. In a crossbow, the axis of arrow travel extends approximately along a crossbow frame, and in a bow, it extends approximately transversely to a middle portion of a bow handle.
The cams can be arranged both directly on the crossbow frame or the bow handle and on appropriate holders, wherein the holders can be made fixed (i.e., rigid), as well as movable (or flexible).
A string at least partially wraps each of the cams.
Both the crossbow and the bow are fitted with cables connecting each cam with at least one of the loose ends of the corresponding limb.
Advantages of the crossbow and the bow according to the present invention will be described below in details with references to drawings illustrating exemplary embodiments of the present invention which is, however, not limited by the described embodiments.
In general, the crossbow comprises a frame 1 with a front side 1.1 and a back side 1.2, a first limb 2 and a second limb 3, a string 4, at least one first cable 5 and at least one second cable 6, and a first cam 7 and a second cam 8.
The first limb 2 has two ends 2a, 2b. The first end or first loose end 2a of the first limb is a loose end, and the second end 2b of the first limb can be either a secured end (
The first limb 2 and the second limb 3 can comprise either one portion (
The loose ends of the limbs 2, 3 can be oriented both in an arrow travel direction (
The limb holders 9, 10 can be made as separate members which are attached from both sides of the frame 1, or can be a part of the frame 1, or can be one integral member (also known as “a riser”) which is attached to the frame 1.
Extended substantially along the frame 1 is an axis 11 of arrow travel along which the arrow (not shown in Figures) is placed when loading into the crossbow and travels on firing.
The first cam 7 and the second cam 8 are mounted on opposite sides, a first side 7a for the first cam 7 and a second side 8a for the second cam 8, of the frame 1 and the axis 11 of arrow travel, respectively. The first cam 7 and the second cam 8 are attached to the frame 1 via a cam holder 12 of the first cam and a cam holder 13 of the second cam. The cam holders 12, 13, a first cam holder 12 and a second cam holder 13, can be both individual separate members or one integral member, and a part of the frame 1, i.e., they can be made integral to the frame 1.
If the cam holders 12, 13 are individual members, they can be made rigid (maintaining the shape and/or dimensions in normal use of the crossbow), i.e. fixed.
Alternatively, the cam holders 12, 13 can be made movable. For instance, the cam holders 12, 13 can be made of a resilient material. Another possible variant includes a movable attachment of the cam holders 12, 13 to the frame 1.
The first cam 7 is arranged so that when at least the first end 2a is at least in a free state (i.e., when the crossbow is not in a drawn state), the first cam 7 is located entirely between the axis 11 of arrow travel and the first end 2a. However, when the crossbow is in the drawn state, it may be preferable to have the cam 7 partially projected beyond the overall dimensions of the limb 2. It is further preferable, in case of the crossbow with the limb 2 having two loose ends as shown in
Similarly, the second cam 8 is arranged so that when at least the first end 3a is at least in a free state (i.e. when the crossbow is not in the drawn state), the second cam 8 is located entirely between the axis 11 of arrow travel and the first end 3a. However, when the crossbow is in the drawn state, it may be preferable to have the cam 8 partially projected beyond the overall dimensions of the limb 3. It is further preferable, in case of the crossbow with the limb 3 having two loose ends as shown in
The cams 7, 8 can be any cams well-known to one of ordinary skill in the art.
The string 4 connects the cams 7, 8 and supplies an initial arrow speed. The cables 5, 6 connect the cams 7, 8 to the first ends 2a, 3a, respectively, as shown in
The cables 5, 6 can be attached to the first ends 2a, 3a (e.g. as shown in
When pulling the string 4 back, the cams 7, 8 start rotating about their axes of rotation (not shown in Figures). The cables 7, 8 are wrapped around the cams 7, 8, thus making the first limb 2 and the second limb 3, respectively, bended. The more rigid the limbs 2, 3 are and the more the limbs 2, 3 bend, the higher the initial arrow speed is.
It is preferable to have the first cable 5 entirely arranged on the same side from the axis 11 of arrow travel as the corresponding first cam 7. Similarly, it is preferable to have the second cable 6 entirely arranged on the same side from the axis 11 of arrow travel as the corresponding second cam 8. In this case, the cables 5, 6 will not intersect the axis 11 of arrow travel, i.e., not interfere with the path of arrow loading and not intersect the arrow travel.
In general, the bow comprises a handle 15 having a midpoint 15.1 with a front side 1.1 and a back side 1.2, a first limb and second limb, a string 4, at least one first cable 5 and at least one second cable 6, and a first cam 7 and a second cam 8.
In the possible embodiments of the bow in accordance with the present invention shown in
The first limb has two ends 2a, 2b. The first end or first loose end 2a of the first limb is the loose end, and the second end 2b of the first limb is the fixed end. Similarly, the second limb has ends 3a, 3b. The first end or second loosed end 3a of the second limb is the loose end, and the second end 3b of the second limb is fixed. The fixed ends 2b, 3b can be attached directly to the handle 15 or, as shown in
Extended substantially transversely to the handle 15 approximately in the middle portion thereof is an axis 11 of arrow travel along which an arrow (not shown in Figures) is arranged when loading into the bow and travels on firing.
The first cam 7 and the second cam 8 are mounted on opposite sides of the handle 15 and the axis 11 of arrow travel, respectively. The first cam 7 and the second cam 8 are attached to the handle 15 via a cam holder 12 of the first cam and a cam holder 13 of the second cam. The cam holders 12, 13 can be individual separate members or one integral member, and can be a part of the handle 15, i.e., they can be made integral to the handle 15.
If the cam holders 12, 13 are individual members, they can be made rigid (maintaining the shape and/or dimensions thereof in normal use of the bow), i.e. fixed.
Alternatively, the cam holders 12, 13 can be made movable. For instance, the cam holders 12, 13 can be made of a resilient material. Another possible variant includes a movable attachment of the cam holders 12, 13 to the handle 15.
The first cam 7 is arranged so that when at least the first end 2a is at least in a free state (i.e. when the bow is not in a drawn state), the first cam 7 is located entirely between the axis 11 of arrow travel and the first end 2a. Similarly, the second cam 8 is arranged so that when at least the first end 3a is at least in the free state (i.e. when the bow is not in the drawn state), the second cam 8 is located entirely between the axis 11 of arrow travel and the first end 3a.
The cams 7, 8 can be any cams well-known to one of ordinary skill in the art.
The string 4 connects the cams 7, 8 and supplies an initial arrow speed. The cables 5, 6 connect the cams 7, 8, respectively, to the first ends 2a, 3a.
The cables 5, 6 can be attached to the first ends 2a, 3a, as shown in
When pulling the string 4 back, the cams 7, 8 start rotating about their axes of rotation (not shown in Figures). The cables 7, 8 are wrapped around the cams 7, 8, thus bending the first limb and the second limb, respectively. The more rigid the first limb and the second limb are and the more these limbs bend, the higher the initial arrow speed is.
It is preferable to have the first cable 5 entirely arranged on the same side from the axis 11 of arrow travel as the corresponding first cam 7. Similarly, it is preferable to have the second cable 6 entirely arranged on the same side from the axis 11 of arrow travel as the corresponding second cam 8. In this case, the cables 5, 6 will not intersect the axis 11 of arrow travel, i.e., not interfere with the path of arrow loading and not intersect the arrow travel.
In addition to the indicated above decrease of the overall dimensions while maintaining the firing speed, further advantages of the claimed arrow throwing devices over the known crossbows and bows are worth mentioning.
Firstly, placing the cams closer to the axis of arrow travel and, therefore, to the area which is hand-held by a user during the use of an arrow throwing device allows to reduce the torque developed by said device. This contributes to the more stable holding of the crossbow or bow resulting in lower arm loading, in particular, a user hand loading.
Secondly, since the cams are now displaced from the loose ends of the limbs, the load applied to these loose ends of the limbs is reduced. To attach the cam to the loose end of the limb, as used in the known devices, a tip of the loose end of the limb has to be provided with openings and/or cutouts, and therefore the loose end of the limb has to be reinforced. In addition, during the use of the known devices the cams can slightly shift with respect to attachment axes thereof, thus leading to additional rotational loads applied to the loose ends of the limb. If the cams are not located at the loose ends of the limbs like in the present invention, there is no need to reinforce the loose ends.
Thus, the present invention provides significant advantages over the known crossbows and bows and yet has no impact on one of the main characteristics, namely, the initial speed of arrow flight.
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