TRIGGER MECHANISM FOR CROSSBOW

Abstract

The invention relates to the technical field of athletic equipment, and specifically to a trigger mechanism for crossbow. It comprises a bracket, a trigger system assembled on the bracket and a bow string; said string locking safety device comprises a sear, a sear connecting rod, a sear toggle lever, a trigger connecting rod and a safety button. In the whole attaching string and firing process of the trigger mechanism described in the invention, each hinged point is in pivoting friction contact in a full cycle manner, the contact surface of each hinged point does not change, and the pressure ratio of each contact surface doesn't increase significantly, and an increase in pressure ratio of the contact surface will not occur due to the friction contact surface decrease along with firing; there is no accelerated wear and tear of various moving parts and the service life is long.

Description

1. TECHNICAL FIELD

The invention relates to the technical field of athletic equipment, in particular to a a trigger mechanism for crossbow.

2. BACKGROUND ART

Crossbow is a kind of sports equipment with strong striking force, and its triggering mechanism is mainly composed of trigger system and crossbow string, among which, the trigger system is the main control mechanism of crossbow firing. The safety, operability and maintenance of the trigger system directly affects the efficiency and safety of the crossbow.

In the prior art, the conventional crossbow trigger system comprises an automatic safety device with automatic safety and dry-fire prevention safety functions. The automatic safety device has a bowstring sear, a safety connecting rod, a safety toggle lever, a safety, and a trigger housing hinged on the trigger housing body, contacted and linked in turn. In addition, the power source of the said automatic safety device is the bowstring, and it is destined that the structural size of the automatic safety device will not be too large, every time the trigger is triggered, each contact linkage point will undergo sliding friction, the whole trigger process is a process in which the contact surface changes from a large to a small one, and the positive pressure exerted by the string on the contact surface gradually increases, and at the same time a friction loss is also generated. When the number of shots increased to a certain extent, the wear of the contact linkage points beyond the prescribed limit clearance amount (especially wear in the contact surface detachment section is particularly obvious), the trigger system as a whole scrapped.

Therefore, the service life of trigger system of the existing crossbow trigger mechanism is relatively short, and it needs to be improved urgently.

3. SUMMARY OF THE INVENTION

The invention aims to provide relates a trigger mechanism for crossbow to solve said technical problems.

In order to solve said problem, the technical scheme provided by the invention is as follows:

• • a trigger mechanism for crossbow, comprising a bracket, a trigger system assembled on the bracket and a bow string; said trigger system comprises a trigger and a string locking safety device; said string locking safety device comprises a sear, a sear connecting rod, a sear toggle lever, a trigger connecting rod and a safety button; the middle part of the sear is hingedly connected to the bracket, and its front part is provided with a string groove with opening downward, and its tail end is hingedly connected to the top part of the sear connecting rod; the bottom part of said sear connecting rod is hingedly connected to the top part of the sear toggle lever; the middle part of said trigger connecting rod and the middle part of said sear toggle lever are hingedly assembled on the bracket by toggle lever pin; the bottom front side of said trigger connecting rod is connected with the trigger reset spring, and the top part of said trigger reset spring is connected to the bracket; the top end of said trigger is fixedly connected to the bottom end of said trigger connecting rod; said safety button is assembled at the tail end of the bracket and is capable of moving back and forth along the bracket.

Preferably, a limiting pin is fixed to the bottom end of said sear toggle lever, and a toggle lever reset spring is provided underneath said limiting pin; said toggle lever reset spring is mounted on the toggle lever reset spring pin on the rear side of the upper section of the trigger.

Preferably, on the upper rear side of said sear is provided with a sear reset compression spring; said bracket is mounted with an adjusting bolt for adjusting the pressure on the sear reset compression spring.

Preferably, a buffer pad is fixed on the front upper part of said sear.

Advantageous effects: compared with the prior art, in the whole attaching string and firing process of the trigger mechanism described in the invention, each hinged point is in pivoting friction contact in a full cycle manner, the contact surface of each hinged point does not change, and the pressure ratio of each contact surface doesn't increase significantly, and an increase in pressure ratio of the contact surface will not occur due to the friction contact surface decrease along with firing; there is no accelerated wear and tear of various moving parts and the service life is long.

4. BRIEF DESCRIPTION OF ACCOMPANY DRAWINGS

FIG. 1 is the diagram illustrating the status of preparing to attach string of the trigger mechanism provided by invention.

FIG. 2 is the diagram illustrating the status of attaching string of the trigger mechanism provided by invention.

FIG. 3 is the diagram illustrating the status after attaching string and mounting arrow of of the trigger mechanism provided by invention.

FIG. 4 is the diagram illustrating the status after firing of the trigger mechanism provided by invention.

As shown in the accompanying drawings: 1 bracket, 2 crossbow, 3 connecting rod pin, 4 sear, 5 sear shaft, 6 toggle lever pin, 7 sear pin, 8 sear toggle lever, 9 sear connecting rod, 10 trigger connecting rod, 11 dry-fire prevention piece, 12 adjusting bolt, 13 safety button, 14 push-and-pull pin, 15 trigger, 16 toggle lever reset spring, 17 buffer pad, 18 hook, 19 limiting pin, 20 trigger reset spring pin, 21 trigger reset spring, 22 sear reset compression spring, 23 bow string, 24 rivet, 25 toggle lever reset spring pin, 26 dry-fire prevention piece torsional spring.

5. SPECIFIC EMBODIMENT OF THE INVENTION

The invention is describe d in detail hereinafter with reference to drawings and specific embodiment.

Embodiment

With reference to FIG. 1 to FIG. 4, a trigger mechanism for crossbow described in the embodiment comprises a bracket 1, a trigger system assembled on the bracket 1 and a bow string 23; said trigger system comprises a trigger 15 and a string locking safety device;

• • said string locking safety device comprises a sear 4, a sear connecting rod 9, a sear toggle lever 8, a trigger connecting rod 10 and a safety button 13; the middle part of the sear 4 is hingedly connected to the bracket 1, and its front part is provided with a string groove with opening downward, and its tail end is hingedly connected to the top part of the sear connecting rod 9 via sear pin 7. On the upper rear side of said sear 4 is provided with a sear reset compression spring 22; said bracket 1 is mounted with an adjusting bolt 12 for adjusting the pressure on the sear reset compression spring 22. A buffer pad 17 is fixed on the front upper part of said sear 4.

The bottom part of said sear connecting rod 9 is hingedly connected to the top part of the sear toggle lever 8 via the connecting rod pin 3; the middle part of said trigger connecting rod 10 and the middle part of said sear toggle lever 8 are hingedly assembled on the bracket 1 by toggle lever pin 6; a limiting pin 19 is fixed to the bottom end of said sear toggle lever 8, and a toggle lever reset spring 16 is provided underneath said limiting pin 19; said toggle lever reset spring 16 is mounted on the toggle lever reset spring pin 25 on the rear side of the upper section of the trigger 15.

The bottom front side of said trigger connecting rod 10 is connected with the trigger reset spring 21, and the top part of said trigger reset spring 21 is connected to the trigger reset spring pin 20 under the bracket 1; the top end of said trigger 15 is riveted fixing to the bottom end of said trigger connecting rod 10 via two rivets 24.

Said safety button 13 is assembled at the tail end of the bracket 1 and is capable of moving back and forth along the bracket. At the bottom of the safety button 13 is provided a U-shaped slot with a downward opening, and a block is provided on the top surface of the tail end of said trigger connecting rod 10, and after firing, said block clips into said U-shaped slot.

Under said sear 4 is provided with a dry-fire prevention piece 11, the middle of said dry-fire prevention piece 11 is hingedly assembled to the bracket 1 by means of pin, on which is mounted with a dry-fire prevention piece torsional spring 26. The bottom end of said dry-fire prevention piece 11 is provided with a barb. The front end of said trigger connecting rod 10 is provided with an upwardly tilted hook 18. when not in the firing state, the barb at the bottom end of said dry-fire prevention piece 11 and the hook 18 are connected to each other; after attaching the string and before firing, the top of said dry-fire prevention piece 11 touches the bottom of the front end of the sear 4.

The working principle of the trigger mechanism for crossbow described in the present invention is briefly described as follows:

FIG. 1 shows the state of preparing to attach the string, the sear 4, sear connecting rod 9, sear toggle lever 8, and trigger connecting rod 10 are respectively assembled by hinge; the hinge point is flexible to rotate, and the sear 4, sear connecting rod 9, and sear toggle lever 8 form a double rocker mechanism.

As shown in FIG. 2, when the bow string 23 is attached with the string, the line of the three hinge points of the sear pin 7, the connecting rod pin 3, and the toggle lever pin 6 basically becomes a straight line, and at the same time, the lower part of the sear toggle lever 8 touches the trigger connecting rod 10; the compression force of the sear toggle lever 8 is provided by the sear toggle lever reset spring 16, and it is ensured that the center of the connecting rod pin 3 is on the left side of the line of centers between the sear pin 7 and toggle lever pin 6, which forms the locking state, and the larger the attaching force is, the more reliable the locking is. At the same time, the safety button 13 is moved left to the safety position.

FIG. 3 shows the state after attaching the string and mounting the arrow, the dry-fire prevention piece 11 rotates clockwise, and the barb at its bottom end is disengaged from the hook of the trigger connecting rod 10; in order to open the dry-fire prevention safety before firing, the safety button 13 is pushed to right to the set position.

FIG. 4 shows the firing state, only a small force to pull the trigger 15, the trigger connecting rod 10 is linked to rotate with the toggle lever pin 6 as the center; trigger connecting rod 10 drives the sear toggle lever 8 to rotate at the same time. When the sear toggle lever 8 is slightly rotated, the center of the connecting rod pin 3 is moved to the right side of the line of centers between the sear pin 7 and toggle lever pin 6, and the locking state is released. The sear 4 rapidly rotates in a counterclockwise direction with the sear shaft 5 as the center, and the bow string 23 is rapidly detached from the sear 4, completing one firing of the crossbow.

At the same time, the sear 4 rotates under the action of the sear reset compression spring 22, the top of the front end of the sear 4 is in contact with the buffer pad 17, and the pressure adjustment of the sear reset compression spring 22 can be adjusted by the adjusting bolt 12.

During the entire attaching string and firing process of FIG. 2 to FIG. 4, the size of the locking force of said string locking safety device is determined by the pulling force of bow string 23; when the pull force of bow string 23 is greater, the locking is more reliable and safe.

The above description of the invention and the embodiments thereof is not restricted, and the accompanying drawings are only one of the embodiments of the invention, and the actual structure is not limited thereto. In conclusion, the similar structures and embodiments with the technical scheme of the invention, which are designed by the general skilled person in the art inspired by the invention, without creativity and without departing from the spirit of the invention, should be included in the protection scope of the invention.

Claims

1. A trigger mechanism for crossbow, comprising a bracket (1), a trigger system assembled on the bracket (1) and a bow string (23); said trigger system comprises a trigger (15) and a string locking safety device; said string locking safety device comprises a sear (4), a sear connecting rod (9), a sear toggle lever (8), a trigger connecting rod (10) and a safety button (13); the middle part of the sear (4) is hingedly connected to the bracket (1), and its front part is provided with a string groove with opening downward, and its tail end is hingedly connected to the top part of the sear connecting rod (9); the bottom part of said sear connecting rod (9) is hingedly connected to the top part of the sear toggle lever (8); the middle part of said trigger connecting rod (10) and the middle part of said sear toggle lever (8) are hingedly assembled on the bracket (1) by the toggle lever pin (6); the bottom front side of said trigger connecting rod (10) is connected with the trigger reset spring (21), and the top part of said trigger reset spring (21) is connected to the bracket (1); the top end of said trigger (15) is fixedly connected to the bottom end of said trigger connecting rod (10); said safety button (13) is assembled at the tail end of the bracket (1) and is capable of moving back and forth along the bracket (1).

2. The trigger mechanism for crossbow of claim 1 wherein a limiting pin (19) is fixed to the bottom end of said sear toggle lever (8), and a toggle lever reset spring (16) is provided underneath said limiting pin (19); said toggle lever reset spring (16) is mounted on the toggle lever reset spring pin (25) on the rear side of the upper section of the trigger (15).

3. The trigger mechanism for crossbow of claim 2 wherein on the upper rear side of said sear (4) is provided with a sear reset compression spring (22); said bracket (1) is mounted with an adjusting bolt (12) for adjusting the pressure on the sear reset compression spring (22).

4. The trigger mechanism for crossbow of claim 3 wherein a buffer pad (17) is fixed on the front upper part of said sear (4).