Composite bow capable of automatically adjusting bowstring

Abstract

The utility model discloses an automatic bowstring adjusting composite bow, which belongs to the technical field of composite bows and comprises a bow wheel, a step portion is arranged on the bow wheel, a long circular through hole penetrating through two end faces of the bow wheel is arranged on the step portion, and a balance rod group is arranged in the through hole and comprises a swing rod and a connecting rod. The swing rods penetrate through the through holes and are symmetrically arranged on the two sides of the through holes, and the connecting rods penetrate through the through holes and the swing rods in the radial direction and enable the swing rods to swing in the through holes. The double bowstrings are connected to the two ends of the swing rod, the connecting rod is arranged at the position of the through hole to form a rotating shaft, and the swing rod can rotate along with the connecting rod to achieve the swing effect in the through hole. When the bowstring stresses (tensions) on the two sides of the swing rod are different, the swing rod is driven to rotate until the bowstring stresses on the two sides are the same, the position of the swing rod can be kept stable, and therefore when the composite bow is used, the tensions of the double bowstrings of the composite bow can be automatically adjusted in the string pulling process.

Description

Technical Field

[0001] This utility model relates to a composite bow technology, and more specifically, to a composite bow with automatic bowstring adjustment. Background Technology

[0002] The bowstring of a compound bow can become unbalanced due to mechanical fatigue and changes in temperature and humidity, especially for double-string compound bows. During firing, the bowstring may deviate from the target due to stress variations on one side. For example, if the left bowstring has less stress than the right (the left bowstring is 0.1 cm longer than the right; at a bowstring tension of 50 pounds, the stress difference between the two bowstrings is 50:1), the arrow fired at a distance of 30 meters will deviate 50 cm to the left from the target. Therefore, frequent bowstring adjustments are necessary, but these adjustments are complex and unfriendly to novice users.

[0003] For example, Chinese Patent Publication No. CN217877320U, published on November 22, 2022, entitled "A Composite Bow Piece Adjustment Structure," discloses a scheme for adjusting bow limbs and thus bowstring stress. The scheme includes an adjusting seat with limiting plates on both sides. The adjusting seat is fixed to one end of the composite bow arm by a fixing rod passing through the two limiting plates. The adjusting seat has fixing holes, which are used to fix it to the composite bow arm. Two screw holes are symmetrically arranged on both sides of the fixing holes on the adjusting seat. One end of each of the two bow limbs extends from one side of the adjusting seat, past the fixing rod, to the other side, abutting against screws passing through the two screw holes. The structure is simple and the design is reasonable. However, this scheme increases the load on the bow body and makes adjusting the double bowstring stress difficult, which is not user-friendly for novice users. Utility Model Content

[0004] This invention overcomes the problem of difficult stress adjustment of the double bowstrings in a compound bow, and provides a compound bow with automatic bowstring adjustment. This solution has a simple structure, and during the use of the compound bow, the double bowstrings can automatically adjust their own stress to achieve stress balance, greatly improving the user experience and shooting effect.

[0005] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: an automatic bowstring adjustment compound bow, including a bow wheel, a stepped portion on the bow wheel, and an elongated through hole penetrating both ends of the bow wheel on the stepped portion. A balance bar assembly is arranged in the through hole, the balance bar assembly including a swing rod and a connecting rod. The swing rod passes through the through hole and is symmetrically arranged about both sides of the through hole. The connecting rod passes radially through the through hole and the swing rod, causing the swing rod to swing within the through hole. In this solution, the double bowstrings are connected to both ends of the swing rod, and the connecting rod is arranged at the through hole to form a rotating shaft. The swing rod can rotate together with the connecting rod, thus creating a swinging effect within the through hole. When the bowstring stress (tension) on both sides of the swing rod is different, it will drive the swing rod to rotate until the bowstring stress on both sides is the same, and the position of the swing rod can be kept stable. Therefore, when using the compound bow, the tension of the double bowstrings of the compound bow can be automatically adjusted during the string drawing process, which is very convenient to use.

[0006] Preferably, the radial dimension of the swing rod is adapted to the width of the through hole, and the length of the swing rod is greater than the length of the through hole. Designing a larger radial dimension for the swing rod ensures its structural strength, but also affects its swing range. The length of the swing rod needs to be greater than the length of the through hole to prevent the swing rod from rotating to a position along the length of the through hole.

[0007] Preferably, the swing rod has symmetrically arranged string grooves at both ends, which are arranged circumferentially around the swing rod. The string grooves are used to connect the bowstring and allow the force of the bowstring to act on the swing rod, and then on the bow wheel.

[0008] Preferably, the bow wheel has string-winding grooves on both ends, which are arranged circumferentially along the bow wheel, with each end of the groove located at the upper and lower ends of the stepped portion. The string-winding grooves are used to wind the bowstring, and having both ends on different stepped surfaces avoids interference during the string winding process, improving the winding effect.

[0009] Preferably, the winding groove is aligned with the connecting groove, and the bowstring is housed within the winding groove, with one end of the bowstring connected to the connecting groove. Aligning the winding groove and the connecting groove reduces the force perpendicular to the bowstring, ensuring effective force distribution and reducing wear, while also facilitating bowstring connection.

[0010] Preferably, the ends of the winding groove are arc-shaped, and the arc length of one end of the winding groove, which is located on the same step as the through hole, is greater than the arc length of the other end. The arc-shaped design of the ends of the winding groove can reduce wear on the bowstring.

[0011] Preferably, the connecting rod is fixedly connected to the swing rod, and the connecting rod is rotatably connected to the through hole. To ensure better rotation of the swing rod, the connecting rod and the stepped part are rotatably connected, while the connecting rod and the swing rod are fixed.

[0012] Preferably, the bow wheel has several spokes inside, with at least one spoke connected to the stepped portion. The spokes enhance the structural strength of the bow wheel and improve its torsional resistance. Arranging spokes on the stepped portion also increases the structural strength of the stepped portion, thereby ensuring the stability of structures such as the balance bar assembly.

[0013] Preferably, the connecting rod is provided with fastening components at both ends and on the inner and outer sides of the bow wheel. The fastening components include retaining springs and washers. Providing retaining springs and washers at both ends of the connecting rod can improve the connection strength and positioning accuracy of the connecting rod.

[0014] Compared with the prior art, the beneficial effects of this utility model are: (1) During the string-drawing process, the double bowstrings of the composite bow can automatically achieve tension balance, usually without the need for additional human intervention; (2) The structure is simple and the design is reasonable. The balance bar group has strong structural strength and stability, and can reduce the wear of the bowstring and have a long service life; (3) It can effectively improve the design accuracy, and the adjustment method is simple, which is very friendly to novice users. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the composite bow of this utility model.

[0016] Figure 2 This is a schematic diagram of the bow wheel structure of this utility model.

[0017] Figure 3 This is an exploded view of the bow wheel and balance bar assembly of this utility model.

[0018] Figure 4 This is a schematic diagram of the bowstring connection of this utility model to the balance bar assembly.

[0019] In the diagram: 1. Bow wheel, 2. Stepped section, 3. Through hole, 4. Swing rod, 5. Connecting rod, 6. String groove, 7. String winding groove, 8. Bow string, 9. Spoke, 10. Snap ring, 11. Washer. Detailed Implementation

[0020] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0021] Example 1: As Figures 1 to 4The illustrated compound bow with automatic bowstring adjustment includes bow wheels 1. A set of bow wheels 1 is provided on each of the two bow walls of the compound bow, and the bow wheels 1 are symmetrically arranged on the compound bow. The bow wheels 1 have a cam structure and a stepped portion 2, giving the bow wheels 1 a circumferential height difference. A through hole 3 is provided on the lower side of the stepped portion 2, and the through hole 3 is a hole structure that penetrates the axial end faces of both sides of the bow wheel 1. A balance bar assembly is arranged inside the through hole 3. Two sets of string grooves 7 are provided in the circumferential direction of the bow wheels 1. One end of the string groove 7 is located on the lower side of the stepped portion 2, and the other end of the string groove 7 is located on the higher side of the stepped portion 2. A set of bowstring 1 is provided in each set of string grooves 7, and the two ends of each set of bowstring 1 are respectively connected to the balance bar assembly on the two bow wheels 1.

[0022] Specifically, the balance bar assembly includes a swing rod 4 and a connecting rod 5. The bow wheel 1 is hollow and has several spokes 9 inside, which can effectively reduce the weight of the bow wheel 1 and achieve a lightweight design. The through hole 3 on the bow wheel 1 is an elongated oval hole structure. The swing rod 4 is located at the center of the through hole 3. The connecting rod 5 passes through the inner and outer sides of the bow wheel 1 radially, and passes through the through hole 3 and the swing rod 4 inside the through hole 3. The rotation plane of the swing rod 4 is the same as the plane formed by the length direction and the axial direction of the through hole 3. The connecting rod 5 is perpendicular to the rotation plane of the swing rod 4. The connecting rod 5 and the bow wheel 1 form a rotatable connection, and the connecting rod 5 and the swing rod 4 form a fixed connection. The two bow strings 8 on the two sets of winding grooves 7 of the bow wheel 1 are respectively connected to the two ends of the swing rod 4. When the stress of the bow strings 8 at the two ends of the swing rod 4 is not equal, the tension of the two sets of bow strings 8 on the two ends of the swing rod 4 is not the same. When the tension at the two ends is not equal, the swing rod 4 swings around the connecting rod 5, so that the connecting rod 5 will rotate, causing the swing rod 4 to swing in the through hole 3 until the tension at the two ends of the swing rod 4 is equal.

[0023] Furthermore, the swing rod 4 is a cylindrical rod, and its radial dimension is matched with the width of the through hole 3. The swing rod 4 can rotate normally in the forward or reverse direction within the through hole 3. The matching of the radial dimension of the swing rod 4 with the width of the through hole 3 can increase the structural strength of the swing rod 4 to a certain extent, so as to better withstand the tension of the bowstring 8. In addition, the radial dimension of the swing rod 4 also affects the swing angle of the swing rod 4. When the radial dimension of the swing rod 4 is larger, the swing rod 4 is more likely to abut against the end of the through hole 3 in the longitudinal direction, and the swing range of the swing rod 4 is reduced. Conversely, when the radial dimension of the swing rod 4 is smaller, the swing range of the swing rod 4 will be larger. Therefore, it is necessary to reasonably design the width of the through hole 3 and the radial dimension of the swing rod 4 to ensure the structural strength of the through hole 3 as well as the structural strength and swing angle range of the swing rod 4. Preferably, the swing range of the swing rod 4 should be within ±45°.

[0024] Furthermore, the length of the swing rod 4 also needs to be greater than the length of the through hole 3. The swing rod 4 needs to be long enough to abut against both ends of the through hole 3 along its length, thereby limiting excessive swinging of the swing rod 4. It should be noted that when the swing rod 4 abuts against both ends of the through hole 3 along its length, it indicates that the stress difference between the two sets of bowstrings 8 is large, and the overall length of the bowstrings 8 needs to be manually adjusted further. Therefore, the stress difference between the two bowstrings 8 can also be judged by the degree of deflection of the swing rod 4. When the swing rod 4 basically does not swing and is perpendicular to the plane formed by the length direction and axial direction of the through hole 3, it indicates that the stress of the two bowstrings 8 is the same and is in the optimal state.

[0025] Circular string grooves 6 are provided at both ends of the swing rod 4. The string grooves 6 are mainly used to connect the bowstring 8 to the swing rod 4 and prevent the bowstring 8 from detaching from the swing rod 4. Furthermore, the position of the string groove 6 corresponds to the position of the winding groove 7. When the bowstring 8 is wound on the bow wheel 1 and connected to the string groove 6, the bowstring 8 is located in the plane where the string groove 6 and the winding groove 7 are located. This can effectively prevent the bowstring 8 from bending in opposite directions and causing severe friction with the groove ends of the winding groove 7 or the string groove 6, thus reducing the service life of the bowstring 8.

[0026] The two ends of the winding groove 7 are located at the upper and lower ends of the step 2, respectively. Since the bowstring 8 needs to form a circumferential loop on the bow wheel 1, in order to prevent the bowstring 8 from interfering with itself after one loop, the two ends of the winding groove 7 need to be set with a height difference. Therefore, one end of the winding groove 7 is arranged at the high position of the step 2, and the other end is arranged at the low position of the step 2. This not only makes the bow wheel 1 work less, but also avoids interference of the bowstring 8 and improves the service life of the bowstring 8.

[0027] The specific working principle of this solution is as follows.

[0028] When the stress on the bowstring 8 changes (the stresses on the two bowstrings are not equal), the tension on the bowstring 8 is no longer the same. During the process of fully drawing the bowstring 8, the bow wheel 1 rotates along the direction of bowstring 8's pull, and the contact area between the bowstring 8 and the winding groove 7 gradually decreases. The friction between the bowstring 8 and the winding groove 7 also gradually decreases. When the bowstring 8 is fully drawn, the friction between the bowstring 8 and the winding groove 7 reaches its minimum. Simultaneously, the tension generated by the bowstring 8 also acts on the swing rod 4. Due to the change in internal stress of the bowstring 8, the tension on the two sets of bowstrings 8 is not the same. Two sets of bowstrings 8 are connected to the two ends of the same swing rod 4, so the swing rod 4 will rotate towards the bowstring with greater tension. This causes the tension of the bowstring with greater tension to gradually decrease, while the tension of the bowstring with less tension to gradually increase. When the tension of the two bowstrings 8 is the same, the swing rod 4 will no longer deflect and will tend to stabilize. This achieves automatic adjustment of the tension of the two sets of bowstrings 8 and rebalances the stress inside the two sets of bowstrings 8. In other words, the stress of the bowstrings 8 can be adaptively adjusted during the use of the compound bow without prior calibration.

[0029] Example 2: Figures 1 to 4 The illustrated compound bow with automatic bowstring adjustment includes bow wheels 1. A set of bow wheels 1 is provided on each of the two bow walls of the compound bow, and the bow wheels 1 are symmetrically arranged on the compound bow. The bow wheels 1 have a cam structure and a stepped portion 2, giving the bow wheels 1 a circumferential height difference. A through hole 3 is provided on the lower side of the stepped portion 2, and the through hole 3 is a hole structure that penetrates the axial end faces of both sides of the bow wheel 1. A balance bar assembly is arranged inside the through hole 3. Two sets of string grooves 7 are provided in the circumferential direction of the bow wheels 1. One end of the string groove 7 is located on the lower side of the stepped portion 2, and the other end of the string groove 7 is located on the higher side of the stepped portion 2. A set of bowstring 1 is provided in each set of string grooves 7, and the two ends of each set of bowstring 1 are respectively connected to the balance bar assembly on the two bow wheels 1.

[0030] Specifically, the balance bar assembly includes a swing rod 4 and a connecting rod 5. The bow wheel 1 is hollow and has several spokes 9 inside, which can effectively reduce the weight of the bow wheel 1 and achieve a lightweight design. The through hole 3 on the bow wheel 1 is an elongated oval hole structure. The swing rod 4 is located at the center of the through hole 3. The connecting rod 5 passes through the inner and outer sides of the bow wheel 1 radially, and passes through the through hole 3 and the swing rod 4 inside the through hole 3. The rotation plane of the swing rod 4 is the same as the plane formed by the length direction and the axial direction of the through hole 3. The connecting rod 5 is perpendicular to the rotation plane of the swing rod 4. The connecting rod 5 and the bow wheel 1 form a rotatable connection, and the connecting rod 5 and the swing rod 4 form a fixed connection. The two bow strings 8 on the two sets of winding grooves 7 of the bow wheel 1 are respectively connected to the two ends of the swing rod 4. When the stress of the bow strings 8 at the two ends of the swing rod 4 is not equal, the tension of the two sets of bow strings 8 on the two ends of the swing rod 4 is not the same. When the tension at the two ends is not equal, the swing rod 4 swings around the connecting rod 5, so that the connecting rod 5 will rotate, causing the swing rod 4 to swing in the through hole 3 until the tension at the two ends of the swing rod 4 is equal.

[0031] Furthermore, fastening components are provided at both ends of the connecting rod 5, so that the two ends of the connecting rod 5 can be fixed to the inner and outer sides of the bow wheel 1. Specifically, the fastening components include a retaining spring 10 and a washer 11. The washer 11 is sleeved on the connecting rod 5 and close to the surface of the bow wheel 1. The retaining spring 10 is located on the side of the washer 11 away from the bow wheel 1 and fixes the connecting rod 5.

[0032] Furthermore, the swing rod 4 is a cylindrical rod, and its radial dimension is matched with the width of the through hole 3. The swing rod 4 can rotate normally in the forward or reverse direction within the through hole 3. The matching of the radial dimension of the swing rod 4 with the width of the through hole 3 can increase the structural strength of the swing rod 4 to a certain extent, so as to better withstand the tension of the bowstring 8. In addition, the radial dimension of the swing rod 4 also affects the swing angle of the swing rod 4. When the radial dimension of the swing rod 4 is larger, the swing rod 4 is more likely to abut against the end of the through hole 3 in the longitudinal direction, and the swing range of the swing rod 4 is reduced. Conversely, when the radial dimension of the swing rod 4 is smaller, the swing range of the swing rod 4 will be larger. Therefore, it is necessary to reasonably design the width of the through hole 3 and the radial dimension of the swing rod 4 to ensure the structural strength of the through hole 3 as well as the structural strength and swing angle range of the swing rod 4. Preferably, the swing range of the swing rod 4 should be within ±45°.

[0033] Furthermore, the length of the swing rod 4 also needs to be greater than the length of the through hole 3. The swing rod 4 needs to be long enough to abut against both ends of the through hole 3 along its length, thereby limiting excessive swinging of the swing rod 4. It should be noted that when the swing rod 4 abuts against both ends of the through hole 3 along its length, it indicates that the stress difference between the two sets of bowstrings 8 is large, and the overall length of the bowstrings 8 needs to be manually adjusted further. Therefore, the stress difference between the two bowstrings 8 can also be judged by the degree of deflection of the swing rod 4. When the swing rod 4 basically does not swing and is perpendicular to the plane formed by the length direction and axial direction of the through hole 3, it indicates that the stress of the two bowstrings 8 is the same and is in the optimal state.

[0034] Circular string grooves 6 are provided at both ends of the swing rod 4. The string grooves 6 are mainly used to connect the bowstring 8 to the swing rod 4 and prevent the bowstring 8 from detaching from the swing rod 4. Furthermore, the position of the string groove 6 corresponds to the position of the winding groove 7. When the bowstring 8 is wound on the bow wheel 1 and connected to the string groove 6, the bowstring 8 is located in the plane where the string groove 6 and the winding groove 7 are located. This can effectively prevent the bowstring 8 from bending in opposite directions and causing severe friction with the groove ends of the winding groove 7 or the string groove 6, thus reducing the service life of the bowstring 8.

[0035] The two ends of the winding groove 7 are located at the upper and lower ends of the step 2, respectively. Since the bowstring 8 needs to form a circumferential loop on the bow wheel 1, to prevent the bowstring 8 from interfering with itself after one loop, the two ends of the winding groove 7 need to be set with a height difference. Therefore, one end of the winding groove 7 is arranged at the higher position of the step 2, and the other end is arranged at the lower position of the step 2. This not only makes the bow wheel 1 less strenuous but also avoids interference with the bowstring 8 and improves the service life of the bowstring 8. Both ends of the winding groove 7 are designed with arcs, which can guide the bowstring 8 and reduce wear on the bowstring 8 and the winding groove 7 at the ends. The arc length of the winding groove 7 at the lower side of the step 2 is greater than that at the higher side of the step 2. Since there is also a through hole 3 and a balance bar assembly at the lower position of the step 2, and the bowstring 8 needs to be connected to the balance bar assembly, the arc length of the winding groove 7 at this end needs to be designed to be longer to better connect the swing rod 4 and avoid wear on the bowstring 8.

[0036] Several spokes 9 are provided inside the bow wheel 1 to improve the structural strength of the bow wheel 1. The bow wheel 1 has a hollow structure. There are a total of 7 sets of spokes 9, which are radially distributed along the direction of rotation. The length of each spoke 9 is different. One set of spokes 9 abuts against the step part 2. The spokes 9 enhance the structural strength of the step part 2, thereby ensuring the stability of the balance bar group and other structures.

[0037] The specific working principle of this solution is as follows.

[0038] When the stress on the bowstring 8 changes (the stresses on the two bowstrings are not equal), the tension on the bowstring 8 is no longer the same. During the process of fully drawing the bowstring 8, the bow wheel 1 rotates along the direction of bowstring 8's pull, and the contact area between the bowstring 8 and the winding groove 7 gradually decreases. The friction between the bowstring 8 and the winding groove 7 also gradually decreases. When the bowstring 8 is fully drawn, the friction between the bowstring 8 and the winding groove 7 reaches its minimum. Simultaneously, the tension generated by the bowstring 8 also acts on the swing rod 4. Due to the change in internal stress of the bowstring 8, the tension on the two sets of bowstrings 8 is not the same. Two sets of bowstrings 8 are connected to the two ends of the same swing rod 4, so the swing rod 4 will rotate towards the bowstring with greater tension. This causes the tension of the bowstring with greater tension to gradually decrease, while the tension of the bowstring with less tension to gradually increase. When the tension of the two bowstrings 8 is the same, the swing rod 4 will no longer deflect and will tend to stabilize. This achieves automatic adjustment of the tension of the two sets of bowstrings 8 and rebalances the stress inside the two sets of bowstrings 8. In other words, the stress of the bowstrings 8 can be adaptively adjusted during the use of the compound bow without prior calibration.

Claims

1. A bowstring automatically adjusting compound bow, characterized by, The device includes a bow wheel with a stepped portion. The stepped portion has an elongated through hole that passes through both ends of the bow wheel. A balance bar assembly is installed in the through hole. The balance bar assembly includes a swing rod and a connecting rod. The swing rod passes through the through hole and is symmetrically arranged about both sides of the through hole. The connecting rod passes radially through the through hole and the swing rod, causing the swing rod to swing within the through hole.

2. The automatic bowstring adjustment compound bow of claim 1, wherein, The radial dimension of the swing rod is adapted to the width of the through hole, and the length of the swing rod is greater than the length of the through hole.

3. The automatic bowstring adjustment compound bow of claim 1, wherein, The swing rod has symmetrically arranged chord grooves at both ends, and the chord grooves are arranged in a ring around the circumference of the swing rod.

4. The automatic bowstring adjustment compound bow of claim 3, wherein, The bow wheel has winding grooves on both ends, which are arranged around the bow wheel. The two ends of the winding grooves are respectively located at the upper and lower ends of the stepped portion.

5. A composite bow with automatic bowstring adjustment according to claim 4, characterized in that, The winding groove is aligned with the receiving groove, and a bowstring is provided in the winding groove. One end of the bowstring is connected to the receiving groove.

6. The self-adjusting compound bow of claim 5, wherein, The two ends of the winding groove are arc-shaped, and the arc length of one end of the winding groove, which is located on the same step as the through hole, is greater than the arc length of the other end.

7. The self-adjusting compound bow of any one of claims 1 to 6, wherein the bowstring is a cable. The connecting rod is fixedly connected to the swing rod, and the connecting rod is rotatably connected to the through hole position.

8. The self-adjusting compound bow of claim 7, wherein, The bow wheel has several spokes inside, and at least one spoke is connected to the stepped portion.

9. The automatic bowstring adjustment compound bow of claim 7, wherein, The connecting rod is provided with fastening components at both ends and on the inner and outer sides of the bow wheel. The fastening components include snap rings and washers.

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