This patent specification is based on Japanese patent application, No. 2020-122575 filed on Jul. 17, 2020 in the Japan Patent Office, the entire contents of which are incorporated by reference herein.
The present invention relates to a bow.
Some bows have a plurality of cams or pulleys for winding a string or a cable around them to improve the hit rate.
For example, Patent Documents 1 and 2 disclose a bow called a compound bow having rims at upper end and lower end of a bow body (also called as a handle), wherein a string cam and a cable cam are provided on both rims, a string is wound around the string cam, the cable cam is rotated interlockingly with the string cam to wind a cable and elastically deform the rims.
In addition, Patent Document 3 discloses a bow which is not a compound bow and does not have rims, wherein small diameter pulleys and large diameter pulleys are provided on an upper end and a lower end of a bow body so that the small diameter pulleys and the large diameter pulleys are connected with each other.
[Patent Document 1] U.S. Pat. No. 7,441,555
[Patent Document 2] U.S. Pat. No. 6,688,295
[Patent Document 3] Japanese Patent Application Laid-Open No. S55-33507
In the bows disclosed in Patent Documents 1-3, a grip is formed on the bow body. An archer holds a grip with one hand (hereafter, referred to as a pushing hand), and draws the string or the cable (also called as a drawing operation) with the other hand (hereafter, referred to as a pulling hand). Then, the drawn string or cable is released from the pulling hand.
At that time, since the drawn string or cable is released, the force (i.e. the force corresponding to a drawing weight) applied from the string or the cable to the bow body suddenly changes. As a result, the bow body is unintentionally moved even if the grip is tightly held with the pushing hand. Consequently, an arrow is misaligned and the hit rate is decreased in some cases.
The present invention provides a bow enabling high hit rate.
A bow of the present invention includes: a bow body having a long hole; a grip having a connection pin which is inserted into the long hole and movable in a longitudinal direction of the long hole, the grip being connected with the bow body in a state that the connection pin is inserted into the long hole; and an elastic member that connects the bow body and the connection pin, wherein the elastic member is elastically deformed to apply an elastic force to the bow body and the connection pin when the bow body is moved with respect to the grip by a drawing operation and the connection pin is relatively moved in the longitudinal direction of the long hole.
The bow can include a string that is tensed between one end and the other end of the bow body so that the string is drawn when an arrow is shot, wherein the longitudinal direction of the long hole is directed in a drawing direction which is a direction of drawing the string, and the elastic member applies the elastic force to the bow body in an opposite direction to the drawing direction.
The bow preferably includes a first string cam that is rotatably provided on one end of the bow body; a first pulley that is rotatably provided on the one end of the bow body so as to be located rearward compared to the first string cam; a second string cam rotatably provided on the other end of the bow body; a second pulley that is rotatably provided on the other end of the bow body so as to be located rearward compared to the second string cam, and a string, wherein one end of the string is fixed to the first string cam and the other end of the string is fixed to the second string cam so that the string is tensed between the first string cam and the second string cam, and the string is wound on the first pulley and the second pulley so as to be arranged between the first string cam and the second string cam.
The bow preferably includes a first stopper that is provided on one end of the bow body so that the first stopper is configured to be in contact with the first string cam to stop rotating the first string cam when the string is fully drawn; and a second stopper that is provided on the other end of the bow body so that the second stopper is configured to be in contact with the second string cam to stop rotating the second string cam when the string is fully drawn.
The grip can include: a body portion that extends from the connection pin; and a grip portion that is tillable to the body portion so that a tilt angle can be adjusted.
By using the configuration of the present invention, the elastic member is elastically deformed to apply an elastic force to the bow body and the connection pin when the bow body is moved with respect to the grip by a drawing operation and the connection pin is relatively moved in the longitudinal direction of the long hole. Accordingly, the bow body and the connection pin are returned to the original positional relation by the elastic force of the elastic member when the string is released. As a result, the bow body is prevented from being unintentionally misaligned. Consequently, the misalignment of the arrow is prevented when releasing the string and the hit rate can be improved.
Hereafter, the bow concerning the embodiments of the present invention will be explained in detail with reference to the drawings. Note that the same reference sign is added to the same or similar configuration. In the orthogonal coordinate system XYZ shown in the figures, when a bow body having an arc-shape is directed in a vertical direction and an arrow is shot frontward, the vertical direction is the z direction, the front-back direction is X direction, and the direction orthogonal to the Z direction and the X direction is the Y direction. Hereafter, the above described coordinate system is arbitrarily used in the explanation.
A bow concerning the embodiment of the present invention is the bow that does not have limbs and shoots an arrow by elastically deforming a cable instead of the limbs. The bow has a connection mechanism which connects the bow body with the grip by the connection pin for improving the shooting rate. First, the configuration of the entire bow will be explained with reference to
In
As shown in
The bow body 10 is formed in an arc-shape in a side view to tense the string 40 on the bow body 10. In addition, a large number of notches (cutouts) 101 having a triangle shape in a side view is formed on the bow body 10 to reduce weight. Consequently, plane trusses 102 are formed on the bow body 10. As a result, the bow body 10 has high rigidity and the bow body 10 is hardly deformed.
In the bow body 10, as shown in
Similarly, as shown in
In addition, the reel mounting member 20U has a rotary shaft 203 for supporting the reel 30U. The rotary shaft 203 is linearly extended in the Y-direction and inserted through a not illustrated through hole of the reel 30U. The rotary shaft 203 is supported by the two plane trusses 201. Consequently, the reel mounting member 20U rotatably supports the reel 30U.
Although the reel mounting member 20U is shown and the reel mounting member 20L is not shown in
As shown
The string cam 31U, the small diameter cam 32U and the large diameter cam 33U are coaxially and integrally formed and arranged in the order of the small diameter cam 32U, the string cam 31U and the large diameter cam 33U in the +Y direction. In addition, the string cam 31U, the small diameter cam 32U and the large diameter cam 33U have a not illustrated coaxial through hole so that the above described rotary shaft 203 is inserted into the through hole. Consequently, the string cam 31U, the small diameter cam 32U and the large diameter cam 33U are integrally rotated around the rotary shaft 203.
In the above described cams, the string 40 shown in
Specifically, as shown in
In addition, although it is not illustrated, the string cam 31U is formed in a non-circular shape in a side view so that a small diameter portion and a large diameter portion are connected with each other in the circumferential direction. In other words, the string cam 31U is formed in a shape where curved surfaces having different curvatures are connected in the circumferential direction. Consequently, in the string cam 31U, the force is applied to a portion P to which the string 40 is tensed as shown in
On the other hand, the cables 60, 50 are tensed (installed) on the small diameter cam 32U and the large diameter cam 33U. When the string cam 31U is rotated, the small diameter cam 32U and the large diameter cam 33U are rotated to wind the cables 60, 50 or to loosen and feed the cables 60, 50.
Specifically, as shown in
Although the specific shape of the small diameter cam 32U is different from that of the string cam 31U, the small diameter cam 32U is also formed in a non-circular shape so that a small diameter portion and a large diameter portion are connected with each other in the circumferential direction as shown in
On the other hand, as shown in
Same as the small diameter cam 32U, when the string cam 31U is rotated, the large diameter cam 33U winds the cable 50 or loosens and feeds the cable 50. Since the diameter of the large diameter cam 33U is larger than that of the small diameter cam 32U, the amount of winding and the amount of feeding are large in the large diameter cam 33U compared to the small diameter cam 32U.
Although the position and diameter of the small diameter potion and the large diameter portion of the large diameter cam 33U are different from those of the small diameter cam 32U, the large diameter cam 33U is formed in a non-circular shape same as the small diameter cam 32U as shown in
As shown in
The upper end side of the string 40 is wound around the groove 311 formed on the string cam 31U of the reel 30U, as shown in
On the other hand, the cables 50, 60 are tensed (stretched) from the reel 30U to the reel 30L when the bobbins 55, 65 are attached to the reels 30U, 30L.
Specifically, as shown in
Here, the large diameter cam 33U winds the cable 50 or loosens and feeds the cable 50 as already explained. On the other hand, the small diameter cam 32L is formed in a vertically and horizontally reversed shape with the above described small diameter cam 32U. The small diameter cam 32L winds the cable 50 or loosens and feeds the cable 50. The amount of winding and the amount of feeding are small in the small diameter cam 32L compared to the large diameter cam 33U.
Accordingly, when the string 40 is drawn to rotate the large diameter cam 33U in a direction RU and rotate the small diameter cam 32L in a direction RL as shown in
In addition, as shown in
As already explained, the small diameter cam 32U winds the cable 60 or loosens and feeds the cable 60. On the other hand, the large diameter cam 33L is formed in a vertically and horizontally reversed shape with the above described large diameter cam 33U. The large diameter cam 33L winds the cable 60 or loosens and feeds the cable 60 in larger winding or feeding amount compared to the small diameter cam 32U.
Accordingly, same as the cable 50, when the string 40 is drawn to rotate the small diameter cam 32U in the direction RU and rotate the large diameter cam 33L in the direction RL as shown in
The cables 50, 60 are formed of a thread which is elastically deformed for letting the arrow 70 fly efficiently. For example, the cables 50, 60 are made of polyarylate fiber, aramid fiber, poly para-phenylene benzobisoxazole fiber or the like to increase the tensile strength when the cables 50, 60 are elastically deformed. In addition, as shown in
As explained above, in the bow 1, the reels 30U, 30L elastically deform the cables 50, 60 to store the elastic energy and let the arrow 70 fly by the elastic energy. The elastic energy is generated when the string 40 is drawn and the string cams 31U, 31L are rotated. Accordingly, it is important to control the rotation of the string cams 31U, 31L.
Thus, the reel mounting member 20U has a control member for control the rotation of the string cams 31U, 31L. Then, the control member will be explained.
As the control member, the reel mounting member 20U has a stopper 210 for preventing the string cam 31U from rotating more than a predetermined angle and a string pulley 220 for defining the winding direction of the string 40 to the string cam 31U as shown in
As shown in
On the other hand, as shown in
When the string 40 is fully drawn (i.e., the string 40 is drawn by a predetermined drawing length), the stopper 210 is located at the position to which the pin 312 is revolved. As a result, as shown in
In
The stopper 210 restricts the rotation of the string cam 31U when the stopper 210 is in contact with the pin 312. Consequently, the stopper 210 prevents the string 40 from being drawn more than the predetermined drawing length. As a result, the stopper 210 prevents the string 40 from being drawn more than necessary. Namely, the stopper 210 is configured to be in contact with the string cam 31U to stop rotating the string cam 31U when the string 40 is fully drawn.
On the other hand, as shown in
Although not shown in
In the specification of the present invention, the pulley 220 arranged rearward of the string cam 31U is also referred to as a first pulley and the pulley 220 arranged rearward of the string cam 31L is also referred to as a second pulley in the pulleys 220. In addition, the stopper 210 for restricting the rotation of the string cam 31U is also referred to as a first stopper and the stopper 210 for restricting the rotation of the string cam 31L is also referred to as a second stopper in the stoppers 210. Furthermore, the string cam 31U is also referred to as a first string cam and the string cam 31L is also referred to as a second string cam.
As explained above, since the bow 1 has the stopper 210 for restricting the rotation of the string cams 31U, 31L, the string 40 can be prevented from being drawn exceeding the drawing length determined by the stopper 210. In addition, since the bow 1 has the pulley 220, the string 40 can be wound around the string cams 31U, 31L from the direction determined by the position of the pulley 220.
In addition, the string cams 31U, 31L are provided on the reels 30U, 30L, and the reels 30U, 30L are attached to the bow body 10 without having limbs by the reel mounting members 20U, 20L. Accordingly, the reels 30U, 30L function as a fixed pulley. Consequently, the arrow 70 knocked on the string 40 is hardly displaced. As a result, the shooting rate of the arrow 70 is high.
Meanwhile, when the drawn string 40 is released, the force of the string 40 for pulling the bow body 10 suddenly changes. Accordingly, even if the bow body 10 is tightly held with the pushing hand, the bow body 10 may be unintentionally moved. Consequently, the arrow is displaced and the shooting rate may be decreased.
Thus, a connection mechanism is provided on the bow 1 for preventing the decrease in the shooting rate. Then, the configuration of the connection mechanism will be explained with reference to
As shown in
Specifically, the connection mechanism has a long hole 121 that is formed on the connection portion 12, a connection pin 81 that is connected with the grip 80 and inserted into the long hole 121, and an elastic member 90 that connects the connection pin 81 and the connection portion 12.
The connection portion 12 is provided at the position including a gravity center of the bow body 10. The grip 80 is connected with the bow body 10 in a state that the connection pin 81 is inserted into the long hole 121. The center of the long hole 121 is located at the position corresponding to the gravity center for easily supporting the bow body 10 by the grip 80. Although accessories such as a sight pin 13 and a rest 14 are installed on the arc-shaped portion 11 of the bow body 10, the rest 14 is arranged frontward of the long hole 121. Consequently, the center of the long hole 121 is located on a center line C of the arrow 70 when the arrow 70 is placed on the rest 14 and knocked on the string 40. As a result, the bow 1 can be easily held.
In addition, the longitudinal direction of the long hole 121 is directed in the front-back direction (i.e., X-direction) when the bow body 10 is vertically arranged. Consequently, when the string 40 is drawn, the longitudinal direction of the long hole 121 is directed in the drawing direction which is a direction of drawing the string 40. In addition, the long hole 121 passes through the left-right direction (i.e., Y-direction) of the connection portion 12. A bearing 82 is loosely inserted into the long hole 121.
The connection pin 81 is inserted into the bearing 82 in a state that the bearing 82 is directed in the Y-direction. The bearing 82 rotatably supports the connection pin 81 in the above described direction. On the other hand, the connection pin 81 is fixed to the grip 80 held by an archer 100. Although the archer 100 may move the grip 80, the bearing 82 rotates around the connection pin 81 in the long hole 121 to prevent the movement of the grip 80 from being transferred to the connection portion 12. Consequently, the bearing 82 stabilizes the bow body 10.
In addition, the outer diameter of the bearing 82 is slightly smaller than the short dimension (minor axis) of the long hole 121. Consequently, the bearing 82 (connection pin 81) is movable in the longitudinal direction of the long hole 121. In other words, the bearing 82 can be moved in the drawing direction or the opposite direction to the drawing direction. As a result, the bearing 82 is relatively slid in the long hole 121 when the string 40 is drawn or released to prevent the movement of the bow body 10 from being transferred to the connection pin 81. The left or right end (i.e., +Y end or −Y end) of the connection pin 81 is fixed to the grip 80.
The grip 80 has a body portion 83 that extends downward from the connection pin 81, a grip portion 84that is tilted (tillable) to the body portion 83, and a sling set portion 85 extending rearward from the lower end of the body portion 83. A plurality of screw holes 830 vertically arranged in two lines is formed on the body portion 83. On the other hand, the grip portion 84 is fixed to the body portion 83 by a plurality of not illustrated screws which are screwed in the screw hole 830. The inclination angle (tilt angle) of the grip portion 84 itself to the body portion 83 can be adjusted by changing the screw holes 830 in which the screws are screwed. As a result, the inclination of the grip portion 84 can be adjusted depending on the direction of shooting the arrow 70. Consequently, the arrow 70 can be shot in various directions while keeping appropriate shooting style. In addition, a through hole 851 is formed on the rear end of the sling set portion 85 for inserting a wrist sling 86 which is suspended from an arm of the archer 100 into the through hole 851. The wrist sling 86 prevents the bow 1 from dropping.
On the other hand, the elastic member 90 is attached between the connection pin 81 and a terminal portion 122 of the connection portion 12 located further rearward of the long hole 121.
The elastic member 90 is formed by a spring, a rubber or the like. The elastic member 90 connects the above described connection pin 81 with the terminal portion 122 in a state that the elastic member 90 is extended longer than the natural length. Consequently, the elastic member 90 applies the elastic force in the direction where the connection pin 81 and the terminal portion 122 are mutually approached. As a result, the elastic member 90 makes the connection pin 81 be located at the rear end side of the long hole 121 and makes the bearing 82 abut on the rear end of the long hole 121 in a state that the string 40 is not drawn. The magnitude of the above described elastic force of the elastic member 90 is specified to be same as the magnitude of the force of the later described full draw F shown in
In addition, in a state that the string 40 is drawn, the bow body 10 is pulled rearward and thus the connection pin 81 is relatively moved frontward from the above described rear end side of the long hole 121. Consequently, the elastic member 90 is further elastically deformed in a state that the string 40 is drawn. When the drawing weight is the later described peak weight P, the elastic modulus is specified so that the elastic member 90 is deformed in a range smaller than the length of the longitudinal direction of the long hole 121. Consequently, in a state that the string 40 is drawn, the elastic member 90 is elastically deformed by the distance determined by the drawing weight without being restricted by the long hole 121. As a result, the elastic member 90 absorbs the change of the positional relation between the connection pin 81 and the bow body 10. Consequently, the bow body is prevented from being unintentionally misaligned. As explained above, the elastic member 90 is elastically deformed to apply an elastic force to the bow body 10 and the connection pin 81 when the bow body 10 is moved with respect to the grip 80 by a drawing operation and the connection pin 81 is relatively moved in the longitudinal direction of the long hole 121.
Then, the relation between the drawing weight and the elastic member 90 will be explained in detail with reference to
First, in a state that the string 40 is not drawn, the connection pin 81 is located at the rear end side of the long hole 121 as already explained. The bearing 82 is in contact with the rear end of the long hole 121.
Then, from the above described state, the archer 100 draws the string 40 and the drawing length exceeds the predetermined value, the drawing weight reaches the peak weight P as shown in
Then, when the archer 100 further draws the string 40 to the fully drawn state, as shown in
In this state, when the archer 100 releases the string 40, the drawing length becomes smaller and the drawing weight becomes the peak weight P again. At that time, since the drawing weight becomes larger compared to the timing when the drawing weight is the full draw F, the bow body 10 is pulled rearward more strongly. If the bow 1 does not have the elastic member 90, the bow body 10 is moved rearward and thus the inner wall of the long hole 121 pushes the connection pin 81 rearward. Consequently, the grip 80 is pushed rearward and the bow 1 is displaced unless the archer 100 grasps the grip 80 tightly to keep the connection pin 81 at a fixed position.
However, the elastic member 90 is provided on the bow 1. Consequently, the elastic member 90 is elastically deformed by the peak weight P and the connection pin 81 is kept inside the long hole 121. Namely, the connection pin 81 is relatively moved to the front end side of the long hole 121 by the elastic member 90. As a result, the drawing weight becomes larger compared to the timing when the drawing weight is the full draw F, and the bow body 10 is not interfered with the connection pin 81 even if the bow body 10 is strongly pulled rearward. Thus, the grip 80 is not pushed rearward. Consequently, the displacement of the bow 1 is prevented and the shooting rate of the arrow 70 is increased.
When the time is further lapsed, the drawing weight becomes smaller than the peak weight P, the elastic member 90 is elastically deformed by the drawing weight and the connection pin 81 is relatively kept inside the long hole 121. Consequently, same as when the drawing weight reaches to the peak weight P again, the grip 80 is not pushed rearward and the displacement of the bow 1 is prevented. As a result, the shooting rate of the arrow 70 is increased.
As explained above, the bow 1 concerning the embodiment has the elastic member 90 that is elastically deformed to apply the elastic force to the bow body 10 and the connection pin 81 when the connection pin 81 is relatively moved in the longitudinal direction of the long hole 121. When the string 40 is released, the elastic member 90 restores the positional relation between the bow body 10 and the connection pin 81 to the original state by the elastic force. Thus, the bow body is prevented from being unintentionally misaligned with respect to the connection pin 81. As a result, the shooting rate of the arrow 70 is high.
Since the longitudinal direction of the long hole 121 is directed in the drawing direction of the string 40, the bow body 10 is prevented from being unintentionally misaligned even when the elastic member 90 is elastically deformed in that direction.
The embodiments of the present invention are explained above. However, the present invention is not limited to the above described embodiments. In the above described embodiment, the connection mechanism of the bow body 10 for connecting the connection portion 12 with the grip 80 is provided on the bow 1 for shooting the arrow 70 by elastically deforming the cables 50, 60 instead of the limbs. However, the present invention is not limited to the above described configuration. The connection mechanism of the present invention can be arbitrarily applied to any shooting mechanisms (principle) of the bow 1. For example, the connection mechanism can be provided on compound bows. In this case, the connection mechanism is preferably provided on a handle of the compound bow. Namely, the connection portion 12 having the long hole 121 is formed on the bow body 10 in the specification of the present invention.
In the above described embodiment, the bow body 10 has the connection portion 12 extending rearward from the arc-shaped portion 11 and the long hole 121 is formed on the connection portion 12. However, the present invention is not limited to the above described configuration. The shape of the bow body 10 can be arbitrarily determined in the present invention as long as the long hole 121 is formed on the bow body 10. Accordingly, it is not necessary for the bow body 10 to have the connection portion 12 extending rearward. In this case, the long hole 121 is preferably formed on the arc-shaped portion 11.
In the above described embodiment, the connection pin 81 is fitted in the bearing 82. However, the existence of the bearing 82 can be arbitrarily determined. In the present invention, it is preferred that the connection pin 81 is rotatably supported by the bearing 82 so that the motion of the rotation of the grip 80 is hardly transferred to the bow body 10 to prevent the displacement of the arrow 70 when the string 40 is released and the grip 80 is rotated with respect to the bow body 10. In this case, the bearing 82 is preferably in contact with the inner wall of the long hole 121 so as to be slid smoothly. The types of the bearing 82 can be arbitrarily determined as long as the bearing 82 rotatably supports the connection pin 81. The bearing 82 can be a sliding bearing or a rolling bearing, for example.
In the above described embodiment, the elastic member 90 connects the connection pin 81 with the terminal portion 122 of the bow body 10. However, the present invention is not limited to the above described configuration. The elastic member 90 can be any configurations as long as the elastic member 90 is connected with the bow body 10 and the connection pin 81 to apply the elastic force to the bow body 10 and the connection pin 81 when the connection pin 81 is moved in the longitudinal direction of the long hole 121. In this case, it is preferred that the elastic member 90 applies the elastic force to the bow body 10 in the opposite direction to the drawing direction of the string 40. For example, the elastic member 90 can be a compression spring arranged inside the long hole 121 between the front end of the long hole 121 in the longitudinal direction and the bearing 82.
In the above described embodiment, the string 40 is vertically arranged to shoot the arrow 70 is shot as the usage sample of the bow 1. However, the present invention is not limited to the above described configuration. The direction of the string 40 when shooting the arrow 70 can be arbitrarily determined in the present invention. For example, the arrow 70 can be shot while the string 40 is horizontally arranged. In this case, the above described upper end and lower end of the bow body 10 can be also referred to as left end and right end or one end and the other end of the bow body 10.
1: bow
10: bow body
11: arc-shaped portion
12: connection portion
13: sight pin
14: rest
15: cable pulley
20U, 20L: reel mounting member
30U, 30L: reel
31U, 31L: string cam
32U, 32L: small diameter cam
33U, 33L: large diameter cam
40: string
50, 60: cable
55, 65: bobbin
70: arrow
80: grip
81: connection pin
82: bearing
83: body portion
84: grip portion
85: sling set portion
86: wrist sling
90: elastic member
100: archer
101: notch
102: plane truss
103: connecting rod
121: long hole
122: terminal portion
201: truss
202: connecting rod
203: rotary shaft
210: stopper
211: support member
220: string pulley, pulley
311, 321, 331: groove
312: pin
830: screw hole
851: through hole
C: center line
P: portion
R: radius
DL: dotted line
RL, RU: direction
Number | Date | Country | Kind |
---|---|---|---|
2020-122575 | Jul 2020 | JP | national |