Pneumatic impact tool with a damping structure

Abstract

The present application discloses a pneumatic impact tool with a damping structure, which relates to a hand tool. The pneumatic impact tool with the damping structure comprises a handle, an inner tube and a flow switching valve. The inner tube comprises a ring wall and a chamber, and a hammer is arranged in the chamber to divide the chamber into front and rear chambers. The ring wall is provided with at least one exhaust hole, and the flow switching valve can switch the flow input to the front and rear chambers. The outer circumferential surface of the hammer is provided with an exhaust passage which is communicated with the front chamber and not communicated with the rear chamber. When high-pressure gas is input into the front chamber, the hammer is pushed backward, and the high-pressure gas is discharged through the exhaust passage and the exhaust hole, thereby reducing the pushing force of the hammer.

Description

TECHNICAL FIELD

[0001] The present invention relates to a hand tool, in particular, to a pneumatic impact tool, especially to a pneumatic impact tool with a vibration reduction structure. BACKGROUND

[0002] The pneumatic impact tool will generate vibration during use due to the reciprocating displacement of the hammer. Long-term use will have adverse effects on the palm of the user's hand. In particular, the more powerful the impact force of the pneumatic impact tool, the greater the vibration it will cause, and the greater the harm it will cause to the user. Therefore, it must be improved.

[0003] Taiwanese invention patent publication I235700 and I729809 respectively disclose a pneumatic tool. In the structure of the barrel of the pneumatic tool, a gas chamber is provided at the rear to press the air in the gas chamber when the hammer moves backward, thereby generating a buffering effect and reducing the vibration of the hammer on the barrel. Figure 4 of I729809 discloses another pneumatic tool. A spring or a rubber block is provided at the rear of the barrel to push the spring or the rubber block when the hammer moves backward, thereby deforming to generate a buffering effect and reducing the vibration of the hammer on the barrel.

[0004] Both of the above-mentioned known structures are additional components (changing the spatial configuration to form a gas chamber, adding a spring or a rubber block, etc.) attached to the existing structure of the pneumatic tool. After the pneumatic tool generates a large amount of vibration, the vibration is reduced by buffering. In addition to the disadvantage of increased cost, the most important thing is that the vibration reduction effect is not ideal, and the user will still feel discomfort in the hand during operation.

[0005] The structure disclosed in Figure 5 of I235700 has an air inlet pipe connected to the front end of the barrel to move the hammer that has moved to the front end of the barrel backward by high-pressure gas, and a vent hole is provided at about the middle position of the barrel for pressure relief. However, during the process of the hammer hitting the tool head forward and rebounding backward, the high-pressure gas in the barrel can only be released after the hammer passes through the vent hole at the middle position. However, the gas has already driven the hammer to retreat to the rear end of the barrel at high pressure before it is released, thereby hitting the rear end of the barrel with great force, which is the root cause of the vibration of the pneumatic tool.

[0006] Therefore, how to improve the above-mentioned problems is the primary task to be solved by the present invention. SUMMARY

[0007] The main object of the present application is to provide a pneumatic impact tool with a vibration-reducing structure, which has an exhaust passage connecting the front chamber of the inner tube to the outside, so that the exhaust is continuously performed at the beginning of the hammer body's retreat, thereby directly weakening the impact force of the hammer body's retreat and reducing the vibration. The present application thus achieves the vibration-reducing effect without adding extra components.

[0008] To achieve the above object, the present application provides a pneumatic impact tool with a vibration-reducing structure, which comprises:

[0009] a handle having a recess in the interior, the handle having an air inlet passage connecting the recess, wherein the air inlet passage has a flow switch therein;

[0010] a cylinder accommodated in the recess, the cylinder having a flow reversing valve therein, one side wall of the cylinder having a through hole communicating with the air inlet passage to guide the high-pressure gas to the flow reversing valve;

[0011] an inner tube comprising a ring wall fixed to the cylinder and a chamber surrounded by the ring wall, a hammer body tightly fixed to the ring wall being arranged in the chamber so that the chamber is divided into a front chamber and a rear chamber, the front end of the ring wall having a tool head, the ring wall having at least one exhaust hole for communicating the chamber with the outside, the interior of the ring wall having a flow channel connecting the flow reversing valve and the front chamber, the flow channel forming a first air inlet in the front chamber, the rear chamber having a second air inlet connected to the flow reversing valve, the flow reversing valve being capable of switching the flow to be inputted from the first air inlet to the front chamber or from the second air inlet to the rear chamber;

[0012] The hammer body has a head end close to the first air inlet and a tail end close to the second air inlet, the outer periphery of the hammer body having an exhaust passage, wherein the exhaust passage extends to the head end and communicates with the front chamber, and the exhaust passage is not connected to the tail end, thereby not communicating with the rear chamber, when the high-pressure gas is injected from the second air inlet to the rear chamber, the hammer body is pushed by the high-pressure gas to move towards the tool head; when the high-pressure gas is injected from the first air inlet to the front chamber, the hammer body is pushed by the high-pressure gas to move away from the tool head, in the process, when the exhaust passage of the hammer body communicates with the exhaust hole, the high-pressure gas in the front chamber is exhausted through the exhaust passage and the exhaust hole, thereby reducing the pushing force of the hammer body.

[0013] In one embodiment, the exhaust passage is constituted by a helical groove recessed on the outer periphery of the hammer body.

[0014] Preferably, the groove is in communication with the exhaust hole when the hammer is in a position in contact with the tool head. Further, the ring wall is provided with three exhaust holes, each of which is different in distance from the tool head; when the hammer is in a position in contact with the tool head, the groove is in communication with the two exhaust holes closest to the tool head.

[0015] In another embodiment, the exhaust passage includes a groove portion and a cylindrical gap. The groove portion extends linearly along the direction of movement of the hammer to the head end and communicates with the front chamber. The cylindrical gap is the space between a belt-shaped recess of the outer periphery of the hammer and the ring wall.

[0016] Preferably, the cylindrical gap is in communication with the exhaust hole when the hammer is in a position in contact with the tool head. Further, the ring wall is provided with three exhaust holes, each of which is different in distance from the tool head; when the hammer is in a position in contact with the tool head, the cylindrical gap is in communication with the two exhaust holes closest to the tool head.

[0017] Preferably, the distance between the exhaust hole and the tool head is not greater than half the total length of the chamber.

[0018] The above objects and advantages of the present application can be more fully understood from the following detailed description of the preferred embodiments when taken in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 Fig. 1 is a perspective view of the overall structure of a first embodiment of the present application;

[0020] Fig. 2 Fig. 2 is a cross-sectional view of the overall structure of the first embodiment of the present application;

[0021] Fig. 3 Fig. 3 is a perspective view of the hammer of the first embodiment of the present application;

[0022] Figs. 4-6 Fig. 4 is a schematic view of the action state of the first embodiment of the present application;

[0023] Fig. 7 Fig. 5 is a perspective view of the overall structure of a second embodiment of the present application;

[0024] Fig. 8 Fig. 6 is a cross-sectional view of the overall structure of the second embodiment of the present application;

[0025] Fig. 9 Fig. 7 is a perspective view of the hammer of the second embodiment of the present application;

[0026] Figs. 10-12 Fig. 8 is a schematic view of the action state of the second embodiment of the present application.

[0027] MAIN REFERENCE NUMERALS

[0028] rear chamber 322 of handle 1

[0029] recess 11 air flow passage 33

[0030] air inlet passage 12 first air inlet 34

[0031] air flow switch 13 second air inlet 35

[0032] button 14 air outlet hole 36

[0033] spring 15 hammer body 4

[0034] cylinder 2 head end 41

[0035] through hole 21 tail end 42

[0036] air flow reversing valve 22 outer peripheral surface 43

[0037] inner tube 3 groove 44

[0038] annular wall 31 tool head 5

[0039] chamber 32 hammer 9

[0040] front chamber 321 head end 91

[0041] tail end 92 cylindrical gap 96

[0042] outer peripheral surface 93 belt-shaped recess 97

[0043] groove portion 95 DETAILED DESCRIPTION

[0044] Please refer to Figs. 1-2 , the first embodiment of the pneumatic impact tool provided with a damping structure of the present application is shown, including a handle 1, a cylinder 2, an inner tube 3 and a hammer 4. The handle 1 can be formed as a pistol shape or a straight cylinder shape, in this embodiment, the handle 1 is a pistol shape. The top of the handle 1 is provided with a recess 11. The bottom of the handle 1 is provided with an air inlet passage 12 extending upward and communicating with the recess 11, for connecting to an external high-pressure gas supply source. The air inlet passage 12 is provided with an air flow switch 13 for controlling the air flow, and a button 14 is connected to the air flow switch 13 on one side of the handle 1 for operation.

[0045] The cartridge 2 is accommodated in the recess 11, and the bottom end of the recess 11 is provided with a spring 15 for buffering the cartridge 2. The side wall of the cartridge 2 is provided with a through hole 21 communicating with the air inlet channel 12, and the cartridge 2 is provided with a well-known air flow reversing valve 22. After high-pressure gas is introduced into the air inlet channel 12, the high-pressure gas enters the air flow reversing valve 22 through the through hole 21. The air flow reversing valve 22 is used to output high-pressure gas in two different paths.

[0046] The inner tube 3 is a circular tube structure having a ring wall 31 and a chamber 32 surrounded by the ring wall 31. The ring wall 31 extends into the cartridge 2 and is screwed to the cartridge 2. The chamber 32 is provided with a hammer 4 abutting against the ring wall 31, thereby separating the chamber 32 into a front chamber 321 and a rear chamber 322. The inner tube 3 extends out of the cartridge 2, and the front end of the inner tube 3 is provided with a tool head 5 which can be replaced according to actual use requirements. The ring wall 31 is provided with an air flow channel 33 communicating with the air flow reversing valve 22, and the air flow channel 33 forms a first air inlet 34 in the front chamber 321. The rear chamber 322 is provided with a second air inlet 35 connected to the air flow reversing valve 22. Accordingly, the air flow reversing valve 22 can selectively output high-pressure gas to the air flow channel 33 at a proper time, and then inject the high-pressure gas into the front chamber 321 through the first air inlet 34. Alternatively, the air flow reversing valve 22 can inject high-pressure gas into the rear chamber 322 through the second air inlet 35.

[0047] Further, the ring wall 31 is provided with at least one exhaust hole 36 for connecting the chamber 32 to the outside. In the embodiment, the number of exhaust holes 36 is three, which are arranged in a straight line along the axial direction of the inner tube 3, and the distances between each exhaust hole 36 and the tool head 5 are different. Furthermore, the three exhaust holes 36 are arranged between the first air inlet 34 and the second air inlet 35, and the distance between the exhaust hole 36 and the tool head 5 is not greater than half the total length of the chamber 32.

[0048] As shown in Figs. 2-3 The hammer 4 includes a head end 41 close to the first air inlet 34 and a tail end 42 close to the second air inlet 35, and has an outer peripheral surface 43 between the head end 41 and the tail end 42. The outer diameter of the hammer 4 is equal to the inner diameter of the chamber 32, thereby abutting the outer peripheral surface 43 against the ring wall 31. The outer peripheral surface 43 is provided with an exhaust passage. The exhaust passage extends to the head end 41 and communicates with the front chamber 321, and the exhaust passage is not connected to the tail end 42, thereby not communicating with the rear chamber 322. In the embodiment, the exhaust passage is formed by a groove 44 recessed on the outer peripheral surface 43. The groove 44 extends in a spiral shape, and the number and pitch of the groove 44 can be changed according to design requirements.

[0049] In this embodiment, the relative position relationship between the groove 44 and the exhaust holes 36 is shown in Fig. 6. Specifically, when the hammer 4 moves to the position contacting the tool head 5, the groove 44 is in communication with the two exhaust holes 36 closest to the tool head 5. Fig. 4

[0050] By the above structure, when the air flow switch 13 is controlled by pressing the button 14 to make the high-pressure gas flow into the air flow reversing valve 22 through the air inlet passage 12, the air flow reversing valve 22 first injects the high-pressure gas from the second air inlet 35 into the rear chamber 322, at this time, the high-pressure gas pushes the hammer 4 to move forward at high speed and impact the tool head 5 to generate working effect. Then, the air flow reversing valve 22 switches the air supply path, stops injecting the high-pressure gas from the second air inlet 35 into the rear chamber 322, and instead injects the high-pressure gas into the air flow passage 33, and then injects the high-pressure gas from the first air inlet 34 into the front chamber 321. The technique of switching the air supply path of the air flow reversing valve 22 is a common and well-known technique, which will not be described here.

[0051] At this time, the high-pressure gas starts to push the hammer 4 to move backward. As shown in Fig. 6, when the hammer 4 starts to move away from the tool head 5, the high-pressure gas in the front chamber 321 can start to leak out through the channel formed by the groove 44 and the exhaust hole 36 in communication, thereby reducing the pressure in the front chamber 321 and weakening the force pushing the hammer 4, so that when the hammer 4 moves to the end of the stroke as shown in Fig. 6, the amplitude of the vibration will be reduced. Fig. 4 In addition, in the process of reducing vibration, when the hammer 4 is at the start of the stroke as shown in Fig. 6, the groove 44 is in communication with the exhaust hole 36, at this time, the air can start to leak, in other words, the timing of air leakage of the present application is greatly earlier than that of the known structure, so that the force pushing the hammer 4 can be greatly weakened.

[0052] Fig. 4 Furthermore, during the process of the hammer 4 moving backward, the groove 44 can be in communication with different exhaust holes 36 to continuously leak air as shown in Fig. 6, thereby continuously weakening the force pushing the hammer 4 to move backward, so that the vibration will be greatly reduced.

[0053] The feature of the present application is to directly weaken the impact force of the hammer 4 moving backward by air leakage at the source of vibration of the pneumatic tool (i.e. the impact force of the hammer 4 moving backward), so as to achieve the purpose of treating the root cause, thereby producing a better vibration reduction effect than the known structure, while not affecting the force of the high-pressure gas driving the hammer to move forward and impact the tool head, so as to produce the vibration reduction effect while taking into account the output power of the pneumatic tool. Fig. 5

[0054]

[0055] Figs. 7-9 ​​​​This is the second embodiment of the present invention, which is a pneumatic impact tool with the same structure as the above embodiment. The difference is the structure of the hammer body 9. Therefore, the structure of the above embodiment will be included in the following description.

[0056] The hammer body 9, like in the above embodiment, has a head end 91 and a tail end 92, with an outer peripheral surface 93 between them. An exhaust channel is provided on the outer peripheral surface 93, extending to the head end 91 and communicating with the front chamber 321, as in the above embodiment. However, the exhaust channel is not connected to the tail end 92, and therefore does not communicate with the rear chamber 322. In this embodiment, the exhaust channel includes a groove portion 95 and a cylindrical gap 96. The groove portion 95 extends linearly along the moving direction of the hammer body 9, with one end connected to the head end 91 and communicating with the front chamber 321, and the other end connected to the cylindrical gap 96. The cylindrical gap 96 is the space between a strip-shaped recess 97 recessed from the outer peripheral surface 93 and the annular wall 31.

[0057] Therefore, the relative positional relationship between the exhaust channel and the exhaust port 36 is as follows: Fig. 10 As shown. Specifically, in this embodiment, when the hammer body 9 moves to the position of contacting the tool head 5, the cylindrical gap 96 is connected to the two exhaust holes 36 closest to the tool head 5.

[0058] Similar to the first embodiment, in this embodiment, when the hammer 9 is in such a position... Fig. 10 At the starting point of the stroke shown, the vent hole 36 is connected through the cylindrical gap 96, allowing air to begin venting. In other words, the venting timing is significantly earlier than in well-known structures. During the retraction of the hammer 9, it can be as follows... Fig. 11 As shown, different vent holes 36 are connected through the cylindrical gap 96 to continuously release air, thereby, as in the first embodiment, continuously weakening the force that pushes the hammer 9 backward, so that the hammer 9 reaches... Fig. 12 At the end of the journey, the vibration was significantly reduced.

[0059] The above embodiments are disclosed only to illustrate the present invention and are not intended to limit the present invention. Any substitution of equivalent components should still fall within the scope of the present invention.

[0060] In summary, this invention demonstrates to those skilled in the art that it can indeed achieve the aforementioned objectives, and thus complies with the provisions of the Patent Law; therefore, this application is filed in accordance with the law.

Claims

1. A pneumatic impact tool with a vibration damping structure, characterized in that, It comprises: a handle, which has a recess inside, the handle has an air inlet channel connected to the recess, wherein the air inlet channel has an air flow switch; a cylinder, which is accommodated in the recess, the cylinder has an air flow reversing valve, one side wall of the cylinder has a through hole, which is connected to the air inlet channel, so that high pressure gas is introduced into the air flow reversing valve; an inner tube, which comprises a ring wall fixed to the cylinder and a cavity surrounded by the ring wall, a hammer fixed to the ring wall is located in the cavity, so that the cavity is divided into a front cavity and a rear cavity, the front end of the ring wall has a tool head, the ring wall has three exhaust holes, which connect the cavity to the outside, the distance between each exhaust hole and the tool head is different, the distance between each exhaust hole and the tool head is not more than half of the total length of the cavity, the ring wall has an air flow channel, which connects the air flow reversing valve and the front cavity, the air flow channel forms a first air inlet in the front cavity, the rear cavity has a second air inlet connected to the air flow reversing valve, air flow can enter the front cavity from the first air inlet, or enter the rear cavity from the second air inlet; the hammer has a head end close to the first air inlet and a tail end close to the second air inlet, the outer surface of the hammer has an exhaust channel, which is composed of a spiral groove recessed on the outer surface of the hammer, wherein the groove extends to the head end and is connected to the front cavity, and the groove is not connected to the tail end, thereby not connected to the rear cavity, when high pressure gas is injected into the rear cavity from the second air inlet, the hammer is pushed by high pressure gas and moves towards the tool head; when the hammer is located at a position in contact with the tool head, the groove is connected to the two exhaust holes closest to the tool head, when high pressure gas is injected into the front cavity from the first air inlet, the hammer is pushed away from the tool head by high pressure gas, in the process, when the groove is connected to each exhaust hole, high pressure gas in the front cavity is discharged through the groove and each exhaust hole, thereby reducing the force pushing the hammer.

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