String pulling mechanism of crossbow

Abstract

A string pulling mechanism includes a rolling assembly, a rotary shaft, a unidirectional bearing, two rollers, a switch, and a swing lever. The holder has a first accommodation portion, an opening, and a first coupling orifice. The unidirectional bearing includes an internal ring and an external ring having multiple teeth, the two rollers are fixed on the rotary shaft, and the switch is inserted to the opening of the rolling assembly and is rotatably connected with the rolling assembly. The switch is received into the opening so as to control the external ring to rotate or not rotate. The swing lever disposed on a side of the rolling assembly to actuate the rotary shaft, the internal ring of the unidirectional bearing, and the two rollers to rotate. The string is fixed on the two rollers and are inserted through and connected with a pull seat.

Claims

1. A string pulling mechanism of a crossbow comprising: a string collector including a rolling assembly, a rotary shaft, a unidirectional bearing, two rollers, a switch, and a swing lever; the rolling assembly having a first accommodation portion formed on a middle thereof, an opening communicating with the first accommodation portion, a first coupling orifice passing through the first accommodation portions, the rotary shaft being rotatably inserted into the first coupling orifice of the rolling assembly; the unidirectional bearing received in the first accommodation portion of the rolling assembly and fitted on the middle of the rotary shaft, the unidirectional bearing having an internal ring and an external ring fitted around an outer rim of the internal ring, wherein the internal ring is connected with the rotary shaft, the external ring has multiple teeth surrounding an outer rim thereof, wherein the internal ring rotates unidirectionally with respective to the external ring, the two rollers are fixed on two sides of the rotary shaft, the switch is inserted to the opening of the rolling assembly and is rotatably connected with the rolling assembly, wherein the switch is received into the opening so as to control the external ring to rotate or not rotate; the swing lever disposed on a side of the rolling assembly to actuate the rotary shaft, the internal ring of the unidirectional bearing, and the two rollers to rotate; and wherein two ends of the string are fixed on the two rollers, and the string is inserted through and connected with a pull seat.

2. The string pulling mechanism as claimed in claim 1, wherein the rolling assembly has a holder, a cap disposed on the holder, and two lids connected on two sides of the holder, wherein the holder has a first connection part and a second connection part connected with the first connection part.

3. The string pulling mechanism as claimed in claim 1, wherein the rolling assembly includes a locating portion arranged on a front end of the rolling assembly.

4. The string pulling mechanism as claimed in claim 1, wherein the rolling assembly further has a second coupling orifice formed a front end thereof parallel to the first coupling orifice and configured to receive the string.

5. The string pulling mechanism as claimed in claim 1, wherein the unidirectional bearing has multiple recesses equidistantly formed on an inner rim of the external ring, wherein a respective recess has a first segment and a second segment, and a depth of the first segment is greater than a depth of the second segment, wherein the respective recess accommodates a rolling element and a spring, and the rolling element is pushed by the spring to move from the first segment to the second segment so that the rolling element moves back to the second segment automatically.

6. The string pulling mechanism as claimed in claim 1, wherein the string collector further includes a resilient element defined between the switch and the rolling assembly so as to push the insertion of the switch to the external ring of the unidirectional bearing.

7. The string pulling mechanism as claimed in claim 6, wherein the resilient element is a spring.

8. The string pulling mechanism as claimed in claim 1, wherein the swing lever is disposed on a side of the rolling assembly to lock with the rotary shaft and to actuate one of the two rollers.

9. The string pulling mechanism as claimed in claim 1, wherein the string collector includes two first sleeves, the two first sleeves are fitted on an outer rim of the rotary shaft and are defined among the unidirectional bearing and the two rollers.

10. The string pulling mechanism as claimed in claim 9, wherein the string collector includes the two second sleeves, and the two second sleeves are fitted on an outer rim of the rotary shaft and are defined among the two first sleeves and the two rollers.

11. The string pulling mechanism as claimed in claim 1, wherein the switch has an operation portion extending out of the opening, and the switch has an insertion received into the opening, wherein the insertion is engaged between two teeth of the external ring of the unidirectional bearing.

12. The string pulling mechanism as claimed in claim 1, wherein the rolling assembly has two second accommodation portions configured to receive the two rollers.

13. The string pulling mechanism as claimed in claim 1, wherein the pull seat is in a U shape and includes two hooks portion arranged on two bottoms of two middles of two sides thereof, and the pull seat includes two rolling wheels rotatably connected on the two sides of the pull seat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view showing the assembly of a crossbow according to a preferred embodiment of the present invention.

(2) FIG. 2 is a perspective view showing the exploded components of the crossbow according to the preferred embodiment of the present invention.

(3) FIG. 3 is a perspective view showing the assembly of a part of the crossbow according to the preferred embodiment of the present invention.

(4) FIG. 4 is a perspective view showing the exploded components of a part of the crossbow according to the preferred embodiment of the present invention.

(5) FIG. 5 is another perspective view showing the exploded components of a part of the crossbow according to the preferred embodiment of the present invention.

(6) FIG. 6 is a side plan view showing the assembly of a part of the crossbow according to the preferred embodiment of the present invention.

(7) FIG. 7 is a cross sectional view taken along the line VII-VII of FIG. 6.

(8) FIG. 8 is a cross sectional view taken along the line VIII-VIII of FIG. 6.

(9) FIG. 9 is a cross sectional view showing the operation of a part of the crossbow according to the preferred embodiment of the present invention.

(10) FIG. 10 is an amplified cross sectional view of a portion A1 of FIG. 9.

(11) FIG. 11 is another cross sectional view showing the operation of a part of the crossbow according to the preferred embodiment of the present invention.

(12) FIG. 12 is also another cross sectional view showing the operation of a part of the crossbow according to the preferred embodiment of the present invention.

(13) FIG. 13 is an amplified cross sectional view of a portion A2 of FIG. 12.

(14) FIG. 14 is a perspective view showing the operation of the crossbow according to the preferred embodiment of the present invention.

(15) FIG. 15 is still another cross sectional view showing the operation of a part of the crossbow according to the preferred embodiment of the present invention.

(16) FIG. 16 is an amplified cross sectional view of a portion A3 of FIG. 15.

(17) FIG. 17 is a perspective view showing the exploded components of a conventional crossbow.

(18) FIG. 18 is a perspective view showing the exploded components of a string pulling mechanism of the conventional crossbow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(19) The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, a preferred embodiment in accordance with the present invention.

(20) With reference to FIGS. 1 and 2, a crossbow according to a preferred embodiment of the present invention comprises a body 1, a limb 2, a string pulling mechanism 3, a fixing orifice 4 defined on a rear end of the body 1, a trigger assembly 5 located adjacent to a rear end of the body 1, and a bowstring 6 defined between two ends of the limb 2, wherein the limb 2 is curved and is mounted proximate to a front end of the body 1 and intersecting with the body 1 to form a cross shape. The string pulling mechanism 3 includes a string collector 10, a pull seat 20, and a string 30.

(21) Referring to FIGS. 3-8, the string collector 10 includes a rolling assembly 11, a rotary shaft 12, a unidirectional bearing 13, two rollers 14, a switch 15, a resilient element 16, a swing lever 17, two first sleeves 18, and two second sleeves 19.

(22) The rolling assembly 11 has a holder 111, a cap 112 disposed on the holder 111, and two lids 113 connected on two sides of the holder 111, wherein the holder 111 has a first connection part 111A and a second connection part 111B connected with the first connection part 111A, and the rolling assembly 11 has a first accommodation portion 114 formed on a middle thereof, an opening 115 communicating with the first accommodation portion 114, two second accommodation portions 116, a first coupling orifice 117 passing through the first accommodation portions 114 and the two second accommodation portions 116, a locating portion 118 arranged on a front end of the rolling assembly 11, and a second coupling orifice 119 formed on the front end of the rolling assembly 11 parallel to the first coupling orifice 117, wherein the locating portion 118 is in connected with the fixing orifice 4 of a rear end of the body 1.

(23) The rotary shaft 12 is rotatably inserted into the first coupling orifice 117 of the rolling assembly 11.

(24) The unidirectional bearing 13 is received in the first accommodation portion 114 of the rolling assembly 11 and is fitted on the rotary shaft 12. The unidirectional bearing 13 has an internal ring 131 and an external ring 132 fitted around an outer rim of the internal ring 131, wherein the internal ring 131 is connected with the rotary shaft 12, the external ring 132 has multiple teeth 1321 surrounding an outer rim thereof, multiple recesses 1322 equidistantly formed on an inner rim of the external ring 132, wherein a respective recess 1322 has a first segment 1322A and a second segment 1322B, and a depth of the first segment 1322A is greater than a depth of the second segment 1322B, wherein the respective recess 1322 accommodates a rolling element 133 and a spring 134, and the rolling element 133 is pushed by the spring 134 to move from the first segment 1322A to the second segment 1322B so that the rolling element 133 moves back to the second segment 1322B automatically.

(25) The two rollers 14 are received in the two second accommodation portions 116 of the rolling assembly 11 and are fitted with the rotary shaft 12 so that the two rollers 14 actuate the rotary shaft 12.

(26) The switch 15 is inserted to the opening 115 of the rolling assembly 11 and is rotatably connected with the rolling assembly 11, wherein the switch 15 has an operation portion 151 extending out of the opening 115, and the switch 15 has an insertion 152 received into the opening 115, wherein the insertion 152 is engaged between two teeth 1321 of the external ring 132 of the unidirectional bearing 13 so as to control the unidirectional bearing 13 to rotate or not rotate.

(27) The resilient element 16 is defined between the switch 15 and the rolling assembly 11 so as to push the insertion 152 of the switch 15 to the external ring 132 of the unidirectional bearing 13, such that the insertion 152 of the switch 15 is engaged between the two teeth 1321 of the external ring 132 of the unidirectional bearing 13 to position the external ring 132 of the unidirectional bearing 13. In addition, the resilient element 16 is a spring.

(28) The swing lever 17 is disposed on a side of the rolling assembly 11 to lock with the rotary shaft 12 and to actuate one of the two rollers 14, such that the swing lever 17 drives the rotary shaft 12, the internal ring 131 of the unidirectional bearing 13, and the two rollers 14 to rotate.

(29) The two first sleeves 18 are fitted on an outer rim of the rotary shaft 12 and are defined among the unidirectional bearing 13 and the two rollers 14.

(30) The two second sleeves 19 are fitted on an outer rim of the rotary shaft 12 and are defined among the two first sleeves 18 and the two rollers 14.

(31) The pull seat 20 is in a U shape and includes two hooks portion 21 arranged on two bottoms of two middles of two sides thereof, two rolling wheels 22 rotatably connected on the two sides of the pull seat 20, wherein the pull seat 20 is slidably connected on the body 1 so as to be move along the body 1 stably.

(32) The string 30 is rolled on the two rolling wheels 22 of the pull seat 20 and the second coupling orifice 119 of the rolling assembly 11, and two ends of the string 30 are fixed on the two rollers 14.

(33) In operation, as shown in FIGS. 9-14, the two hook portions 21 of the pull seat 20 hook the bowstring 6, the swing lever 17 is rotated to actuate the rotary shaft 12, the internal ring 131 of the unidirectional bearing 13, and the two rollers 14 to revolve, in the meantime, the internal ring 131 revolves relative to the external ring 132, and the rolling element 133 is frictioned by the internal ring 132 to move to the first segment 1322A of the respective recess 1322 to press the spring 134, such that the internal ring 131 and the external ring 132 rotate idly, and the two rollers 14 roll the string 30 so that the rolling element 133 moves to the second segment 1322B of the respective recess 1322 so as to fix between the respective recess 1322 and the internal ring 131 and to be positioned by the switch 15 which mates with the external ring 132. Thereby, the rotary shaft 12, the internal ring 131 of the unidirectional bearing 13, the two rollers 14 rotate reversely to pull the pull seat 20 smoothly, and the bowstring 6 moves to the string collector 10 until the bowstring 6 is pulled to engage with the trigger assembly 5 silently.

(34) With reference to FIG. 15, the operation portion 151 of the switch 15 is pressed so that the insertion 152 of the switch 15 removes from the two teeth 1321 of the external ring 132 of the unidirectional bearing 13, the external ring 132 is not positioned, and the rotary shaft 12, the internal ring 131 of the unidirectional bearing 13, and the two rollers 14 rotate reversely so that the pull seat 20 is pulled back to an original position with the string 30. After releasing the operation portion 151 of the switch 15, the resilient element 16 pushes the insertion 152 of the switch 15 to engage between two teeth 1321 of the external ring 132 of the unidirectional bearing 13, thus re-positioning the external ring 132 of the unidirectional bearing 13.

(35) Accordingly, the string pulling mechanism 3 of the present invention has advantages as follows:

(36) The string pulling mechanism 3 is not driven by a ratchet and does not make any noises, thus avoiding scaring prey away in hunting and enhancing operational practicality.

(37) While various embodiments in accordance with the present invention have been shown and described, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.