PULLEY AND STRING ARRANGEMENT STRUCTURE OF BOW

Abstract

A pulley and string arrangement structure of a bow contains a bow body, an arm assembly, two pulleys, a string fixer, a main string, two first auxiliary strings, and two second auxiliary strings. The bow body includes an arrow-receiving portion. The arm assembly is mounted on the bow body and extends from the bow body. A respective one pulley includes a main string layer, a first and second retraction units, a first and second defining portions, a first and second expansion units, and a first and second locating portions. The main string layer has a guide grove and a positioning portion. The first and second retraction units include a first and second guiding slots. The first and second expansion units include a first and second conduct slots. A center of the arm assembly and the main string layer has a virtual datum plane.

Description

TECHNICAL FIELD

The present invention relates to a bow structure, and more particularly to a pulley and string arrangement structure of the bow.

BACKGROUND

A conventional combined bow contains a bow body, an arm assembly, at least one pulley, and a string, such that the at least one pulley is configured to save a user's force. The bow cannot create an energy, but can transfer the energy. For example, when pulling the string, the arm assembly bends inward, and a bow-pulling force conducts to the arm assembly via the at least one pulley, wherein a deformation of the arm assembly is to transform a kinetic energy of pulling the bow into a potential energy of the deformation of the arm assembly. When releasing the string, the potential energy stored by the arm assembly transfers to an arrow via a displacement of the at least one pulley and the string, thus transforming to a kinetic energy of shooting the arrow.

A modern combined bow contains two pulleys and an auxiliary string connection portion disposed on a side of a respective one pulley so as to form a three-sting structure, wherein the three-string structure has two auxiliary strings and a main string so that the main string is drawn to be deformable, and a kinetic energy of drawing the bow is converted into a potential energy of radially drawing the two strings through the two pulleys, and an arm assembly is pulled to store an energy. When releasing the main string, the arm assembly deforms and actuates the two pulleys via the two auxiliary strings, and the main string is driven by the two auxiliary strings to rebound, hence an arrow on the main string is shot to save labor.

However, the up and down weights of the two pulleys of the three-string structure are not even since the auxiliary string connection portion is disposed on a side of the respective one pulley only. The two pulleys will cause up-and-down deflection and cannot be kept balanced when drawing the main string backward, and a shooting direction of the arrow is not stable enough to influence a shooting accuracy and a hit rate.

The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.

SUMMARY

The primary aspect of the present invention is to provide a pulley and string arrangement structure of a bow that contains two pulleys, wherein a respective one pulley has a main string layer, and the main string layer has a main string connection structure and an auxiliary string connection structure symmetrically fixed on a top and a bottom of the main string layer, such that the two pulleys have an evenly up-and-down weight so that after pulling the main string backward, the two pulleys are kept balanced to not cause an up- and down deflection, thus obtaining a stable shooting direction and enhancing a shooting accuracy and a hit rate.

To obtain the above-mentioned aspect, a pulley and string arrangement structure of a bow provided by the present invention contains a bow body, an arm assembly, two pulleys, a string fixer, a main string, two first auxiliary strings, and two second auxiliary strings.

The bow body includes an arrow receiving portion formed on a top thereof and configured to hold an arrow.

The arm assembly is mounted on the bow body and extends from two sides of the bow body.

The two pulleys are symmetrical and rotatably connected on two ends of the arm assembly, wherein a respective one pulley includes a main string layer, a first and second retraction units and a first and second defining portions which protrude from a top and a bottom of the main string layer, a first and second expansion units and a first and second locating portions which are located on tops and bottoms of the first and second retraction units.

The main string layer has a guide grove defined on an outer side thereof, and a positioning portion formed in the main string layer.

The first and second retraction units include a first and second guiding slots defined on the outer walls of the first and second retraction units, wherein the first guiding slot corresponds to the first defining portion, and the second guiding slot corresponds to the second defining portion.

The first and second expansion units include a first and second conduct slots, the first conduct slot corresponds to the first locating portion, and the second conduct slot corresponds to the second locating portion.

A center of the arm assembly and the main string layer have a virtual datum plane extending along the arrow body, and the virtual datum plane parallel to a center of the first retraction unit has a virtual first top plane, a bottom of the virtual datum plane parallel to a center of the second retraction unit has a virtual first bottom plane, the virtual first top plane parallel to a center of the first expansion unit has a virtual second top plane, and a bottom of the virtual first bottom plane parallel to a center of the second expansion unit has a virtual second bottom plane.

The string fixer is fixed on the bow body adjacent to the arm assembly, and the string fixer includes a first guide roller and a second guide roller which are mounted on two sides of the string fixer.

The main string rolls in two guide groves of the two pulleys via two sides of the bow body, and two ends of the main string move into two recesses to connect with two positioning portions, such that the main string is located on the virtual datum plane.

An end of a respective one first auxiliary string is fitted with a respective one first defining portion and is rolled in the first guiding slot of the first retraction unit, in the meantime, the respective one first auxiliary string is the virtual first top plane, and the other end of the respective one first auxiliary string is fitted with the first locating portion and is rolled in the first conduct slot of the first expansion unit, in the meantime, the respective one first auxiliary string is the virtual second top plane, and a middle section of the respective one first auxiliary string passes through the first guide roller.

An end of a respective one second auxiliary string is fitted with a respective one second defining portion and is rolled in the second guiding slot of the second retraction unit, in the meantime, the respective one second auxiliary string is the virtual first bottom plane, and the other end of the respective one second auxiliary string is fitted with the second locating portion and is rolled in the second conduct slot of the second expansion unit, in the meantime, the respective one second auxiliary string is the virtual second bottom plane, and a middle section of the respective one second auxiliary string passes through the second guide roller.

A front end of the main string is not strung, and the min string is drawn backward to be strung, wherein when not stringing, a length of the respective one first auxiliary string and the respective one second auxiliary string located in the first guiding slot and the second guiding slot is shorter than a length of the respective one first auxiliary string and the respective one second auxiliary string which are strung; when not stringing, a length of the respective one first auxiliary string and the respective one second auxiliary string located in the first conduct slot and the second conduct slot is longer than a length of the respective one first auxiliary string and the respective one second auxiliary string which are strung; when desiring to string to shoot the arrow, the main string is drawn backward to be deformed so that the length of the respective one first auxiliary string and the respective one second auxiliary string located in the first guiding slot and the second guiding slot and the length of the respective one first auxiliary string and the respective one second auxiliary string located in the first conduct slot and the second conduct slot are changeable to store an energy by using a potential energy change, and when releasing the main string, an elastic energy storage of the arm assembly curvedly deforms and an energy storage of the first retraction unit and the second retraction unit are released simultaneously via the main string to release.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the assembly of a pulley and string arrangement structure of a bow according to a preferred embodiment of the present invention.

FIG. 2 is another perspective view showing the assembly of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 3 is a perspective view showing the exploded components of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 4 is a perspective view showing the assembly of a pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 5 is a perspective view showing the assembly of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 6 is a side plane view showing the assembly of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 7 is a top plane view showing the assembly of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 8 is a perspective view showing the assembly of a part of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 9 is a top plane view showing the assembly of a part of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 10 is a bottom plane view showing the assembly of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 11 is a bottom plane view showing the assembly of a part of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 12 is a rear plane view showing the assembly of a part of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 13 is a top plane view showing the operation of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

FIG. 14 is another top plane view showing the operation of the pulley and string arrangement structure of the bow according to the preferred embodiment of the present invention.

DETAILED DESCRIPTION

With reference to FIGS. 1-14, a pulley and string arrangement structure according to a preferred embodiment of the present invention comprises a bow body 10, an arm assembly 20, two pulleys 30, a string fixer 40, a main string 50, two first auxiliary strings 60A, and two second auxiliary strings 60B.

The bow body 10 includes an arrow receiving portion 11 formed on a top thereof and configured to hold an arrow.

The arm assembly 20 is mounted on the bow body 10 and extends from two sides thereof.

The two pulleys 30 are symmetrical and rotatably connected on two ends of the arm assembly 20 by using two shafts 30A, wherein a respective one pulley 30 includes a main string layer 31 (as shown in FIGS. 3-6), a first and second retraction units 32A, 32B and a first and second defining portions 33A, 33B which protrude from a top and a bottom of the main string layer 31, a first and second expansion units 34A, 34B and a first and second locating portions 35A, 35B which are located on tops and bottoms of the first and second retraction units 32A, 32B, wherein the first and second retraction units 32A, 32B are symmetrical, the first and second defining portions 33A, 33B are symmetrical, the first and second expansion units 34A, 34B are symmetrical, and the first and second locating portions 35A, 35B are symmetrical.

The main string layer 31 has a guide grove 311 defined on an outer side thereof, a recess 312 defined in the main string layer 31 and communicating with the guide groove 311, and a positioning portion 313 formed in the recess 312.

The first and second retraction units 32A, 32B shrink the recess 312 and include a first and second guiding slots 321A, 321B defined on the outer walls of the first and second retraction units 32A, 32B, wherein the first guiding slot 321A corresponds to the first defining portion 33A, and the second guiding slot 321B corresponds to the second defining portion 33B.

The first and second expansion units 34A, 34B include a first and second conduct slots 341A, 341B, wherein the first conduct slot 341A corresponds to the first locating portion 35A, and the second conduct slot 341B corresponds to the second locating portion 35B.

A center of the arm assembly 20 and the bow body 10 has a virtual datum plane F1 (as shown in FIG. 12), and the virtual datum plane F1 parallel to a center of the first retraction unit 32A has a virtual first top plane F2, a bottom of the virtual datum plane F1 parallel to a center of the second retraction unit 32B has a virtual first bottom plane F3, the virtual first top plane F2 parallel to a center of the first expansion unit 34A has a virtual second top plane F4, and a bottom of the virtual first bottom plane F3 parallel to a center of the second expansion unit 34B has a virtual second bottom plane F5.

The string fixer 40 is fixed on the bow body 10 adjacent to the arm assembly 20, and the string fixer 40 includes a first guide roller 41A and a second guide roller 41B which are mounted on two sides of the string fixer 40.

The main string 50 rolls in two guide groves 311 of the two pulleys 30 via two sides of the bow body 10, and two ends of the main string 50 move into two recesses 312 to connect with two positioning portions 313, such that the main string 50 is located on the virtual datum plane F1 (as shown in FIG. 12) and spans across the bow body 10.

An end of a respective one first auxiliary string 60A is fitted with a respective one first defining portion 33A and is rolled in the first guiding slot 321A of the first retraction unit 32A, in the meantime, the respective one first auxiliary string 60A is the virtual first top plane F2 (as shown in FIG. 12), and the other end of the respective one first auxiliary string 60A is fitted with the first locating portion 35A and is rolled in the first conduct slot 341A of the first expansion unit 34A, in the meantime, the respective one first auxiliary string 60A is the virtual second top plane F4, and a middle section of the respective one first auxiliary string 60A passes through the first guide roller 41A, wherein the first guide roller 41A is away from the virtual first top plane F2 and is close to the virtual second top plane F4. An end of a respective one second auxiliary string 60B is fitted with a respective one second defining portion 33B and is rolled in the second guiding slot 321B of the second retraction unit 32B, in the meantime, the respective one second auxiliary string 60B is the virtual first bottom plane F3, and the other end of the respective one second auxiliary string 60B is fitted with the second locating portion 35B and is rolled in the second conduct slot 341B of the second expansion unit 34B, in the meantime, the respective one second auxiliary string 60B is the virtual second bottom plane F5, and a middle section of the respective one second auxiliary string 60B passes through the second guide roller 41B, wherein the second guide roller 41B is away from the virtual first bottom plane F3 and is close to the virtual second bottom plane F5. Thereby, the respective one first defining portion 33A moves to the virtual second top plane F4 from the virtual first top plane F2, and the respective one second defining portion 33B moves to the virtual second bottom plane F5 from the virtual first bottom plane F3.

A front end of the main string 50 is not strung, and the main string 50 is drawn backward to be strung (as shown in FIG. 7). When not stringing, a length of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B located in the first guiding slot 321A and the second guiding slot 321B is shorter than a length of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B which are strung. When not stringing, a length of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B located in the first conduct slot 341A and the second conduct slot 341B is longer than a length of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B which are strung. Referring to FIGS. 13 and 14, when desiring to string to shoot the arrow, the main string 50 is drawn backward to be deformed so that the length of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B located in the first guiding slot 321A and the second guiding slot 321B and the length of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B located in the first conduct slot 341A and the second conduct slot 341B are changeable to store an energy by using a potential energy change, and when releasing the main string 50, an elastic energy storage of the arm assembly 20 curvedly deforms and an energy storage of the first retraction unit 32A and the second retraction unit 32B are released simultaneously via the main string 50 to shoot the arrow on the main string 50, thus achieving a stronger shooting. Furthermore, the two pulleys 30 are connected evenly, and a slope of the respective one first auxiliary string 60A and the respective one second auxiliary string 60B is small, when releasing the main string 50, the two pulleys 30 are kept balanced to not cause an up-and-down deflection to maintain a stable shooting direction, thus enhancing a shooting accuracy and a hit rate.

While the first embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. The scope of the claims should not be limited by the first embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

1. A pulley and string arrangement structure of a bow comprising: a bow body, an arm assembly, two pulleys, a string fixer, a main string, two first auxiliary strings, and two second auxiliary strings; wherein the bow body includes an arrow receiving portion formed on a top thereof and configured to hold an arrow;the arm assembly is mounted on the bow body and extends from two sides of the bow body;the two pulleys are symmetrical and rotatably connected on two ends of the arm assembly, wherein a respective one pulley includes a main string layer, a first and second retraction units and a first and second defining portions which protrude from a top and a bottom of the main string layer, a first and second expansion units and a first and second locating portions which are located on tops and bottoms of the first and second retraction units;the main string layer has a guide grove defined on an outer side thereof, and a positioning portion formed in the main string layer;the first and second retraction units include a first and second guiding slots defined on outer walls of the first and second retraction units, wherein the first guiding slot corresponds to the first defining portion, and the second guiding slot corresponds to the second defining portion;the first and second expansion units include a first and second conduct slots, the first conduct slot corresponds to the first locating portion, and the second conduct slot corresponds to the second locating portion;a center of the arm assembly and the main string layer has a virtual datum plane extending along the arrow body, and the virtual datum plane parallel to a center of the first retraction unit has a virtual first top plane, a bottom of the virtual datum plane parallel to a center of the second retraction unit has a virtual first bottom plane, the virtual first top plane parallel to a center of the first expansion unit has a virtual second top plane, and a bottom of the virtual first bottom plane parallel to a center of the second expansion unit has a virtual second bottom plane;the string fixer is fixed on the bow body adjacent to the arm assembly, and the string fixer includes a first guide roller and a second guide roller which are mounted on two sides of the string fixer;the main string rolls in the two guide groves of the two pulleys via two sides of the bow body, and two ends of the main string move into two recesses to connect with the two positioning portions, such that the main string is located on the virtual datum plane;an end of the respective one first auxiliary string is fitted with the respective one first defining portion and is rolled in the first guiding slot of the first retraction unit, in the meantime, the respective one first auxiliary string is the virtual first top plane, and the other end of the respective one first auxiliary string is fitted with the first locating portion and is rolled in the first conduct slot of the first expansion unit, in the meantime, the respective one first auxiliary string is the virtual second top plane, and a middle section of the respective one first auxiliary string passes through the first guide roller;an end of the respective one second auxiliary string is fitted with the respective one second defining portion and is rolled in the second guiding slot of the second retraction unit, in the meantime, the respective one second auxiliary string is the virtual first bottom plane, and the other end of the respective one second auxiliary string is fitted with the second locating portion and is rolled in the second conduct slot of the second expansion unit, in the meantime, the respective one second auxiliary string is the virtual second bottom plane, and a middle section of the respective one second auxiliary string passes through the second guide roller;a front end of the main string is not strung, and the min string is drawn backward to be strung, wherein when not stringing, a length of the respective one first auxiliary string and the respective one second auxiliary string located in the first guiding slot and the second guiding slot is shorter than a length of the respective one first auxiliary string and the respective one second auxiliary string which are strung; when not stringing, a length of the respective one first auxiliary string and the respective one second auxiliary string located in the first conduct slot and the second conduct slot is longer than a length of the respective one first auxiliary string and the respective one second auxiliary string which are strung; when desiring to string to shoot the arrow, the main string is drawn backward to be deformed so that the length of the respective one first auxiliary string and the respective one second auxiliary string located in the first guiding slot and the second guiding slot and the length of the respective one first auxiliary string and the respective one second auxiliary string located in the first conduct slot and the second conduct slot are changeable to store an energy by using a potential energy change, and when releasing the main string, an elastic energy storage of the arm assembly curvedly deforms and an energy storage of the first retraction unit and the second retraction unit are released simultaneously via the main string to release.

2. The pulley and string arrangement structure as claimed in claim 1, wherein the two pulleys are rotatably connected on the two ends of the arm assembly by using two shafts.

3. The pulley and string arrangement structure as claimed in claim 1, wherein the main string layer has the recess defined in the main string layer and communicates with the guide groove, and the first and second retraction units shrink the recess of the main string layer.

4. The bicycle seat as claimed in claim 1, wherein the first and second retraction units are symmetrical, the first and second defining portions are symmetrical, the first and second expansion units are symmetrical, and the first and second locating portions are symmetrical.