Patent Application
20230226678
The present invention relates to a pneumatic impact tool and more particularly to a vibration reducing structure of pneumatic hammer.
Referring to
A kind of conventional pneumatic hammers which use springs to reduce vibration disclosed in Taiwan Utility Patent No. 471377 and M467540 mainly includes a spring located behind a hammer member. In additional, Patent No. 471377 further recites another spring which is provided in front of the hammer member while Patent No. M467540 further recites an arc sheet which is provided in front of the hammer member. The hammer member that is driven by high pressure gas to move, accordingly, is cushioned by the spring when moving forward and is cushioned by the other spring or the arc sheet when moving backward so that vibration is reduced.
The hammer member 81, however, acts up to several thousand times per minute, that is, the spring or the arc sheet above-mentioned has to bear the deformations several thousand times in one minute. Owing to the nature limitation of material, the deformed spring or arc sheet fails to restore original size so quickly before suffering next compression so as to lower the effect upon vibration reducing.
The primary objective of the present invention is to provide a pneumatic impact tool featuring in that the inner tube member is surrounded by gas to be held firmly and stably, which facilitates vibration reduction.
To achieve the above objective, the present invention provides a vibration reducing structure of pneumatic impact tool including an outer shell, an inner tube member accommodated in the outer shell, a supporting ring and a gas sealing ring. The outer shell has a gas inlet and a gas inlet channel. A hammer member capable of being driven by high pressure gas to move is provided in the inner tube member. The inner tube member includes a less-in-diameter section and a greater-in-diameter section. An outer diameter of the greater-in-diameter section is less than an inner diameter of the outer shell. A gas room connected with the gas inlet channel is formed between a rear end of the greater-in-diameter section and a bottom end of the outer shell. Each of the supporting ring and the gas sealing ring surrounds the greater-in-diameter section and abuts against both the greater-in-diameter section and the outer shell. A cylindrical gap communicated with the gas room is formed between the outer shell and the greater-in-diameter section. The gas sealing ring is located at a position more than half a length of the greater-in-diameter section from the rear end of the greater-in-diameter section.
Preferably, a first gas channel communicated with the gas room is disposed in the inner tube member while a second gas channel is disposed in the hammer member. The second gas channel selectively connects with the first gas channel based on a position of the hammer member so that a moving direction of the hammer member is changed.
Preferably, extending directions of the outer shell, the inner tube member, the gas inlet channel and the first gas channel are all parallel to the moving direction of the hammer member.
Preferably, a stopper is screwed to the rear end of the greater-in-diameter section. The stopper has a protruding portion extending toward the gas room. The protruding portion is sleeved with a spring with one end abutting against the stopper and an opposite end abutting against a recess provided at the bottom end of the outer shell.
Preferably, the stopper is located at a central position of the rear end of the greater-in-diameter section. An interconnection of the gas inlet channel and the gas room is not aligned with the stopper.
Preferably, a front shell is fixed with the outer shell. A tool portion and an impacted portion connected with the tool portion are provided in the front shell. The impacted portion is configured to be hit by the hammer member.
Preferably, the less-in-diameter section of the inner tube member is sleeved with a cushion member abutted against the front shell.
Preferably, a front teeth portion is disposed at an end of the cushion member while a rear teeth portion is disposed at an opposite end of the cushion member. The front teeth portion and the rear teeth portion are staggered.
Preferably, a step portion is formed between the less-in-diameter section and the greater-in-diameter section. The gas sealing ring is disposed close to the step portion
The outer shell 1 is straight. A gas inlet channel 11 is disposed in the outer shell 1. A gas inlet 12 configured to connect with a high pressure gas supplier is provided at a rear end of the outer shell 1. A control valve 13 is disposed in the gas inlet channel 11 for controlling gas to pass through. The control valve 13 can be operated by a trigger 14 located on the outer shell 1.
The inner tube member 2 includes a less-in-diameter section 21 and a greater-in-diameter section 22. A step portion 26 is formed between the less-in-diameter section 21 and the greater-in-diameter section 22. An outer diameter of the greater-in-diameter section 22 is slightly less than an inner diameter of the outer shell 1 so that the greater-in-diameter section 22 is accommodated in the outer shell 1. A gas room 5 is defined between a rear end 20 of the greater-in-diameter section 22 and a bottom end 100 of the outer shell 1. The gas inlet channel 11 connects to the gas room 5 in a shifted position from the center. A cylindrical gap 51 is formed between the greater-in-diameter section 22 and the outer shell 1. It is emphasized that the cylindrical gap 51 communicates with the gas room 5.
Two supporting rings 3 made of hard material for wear-resistance, e.g. polytetrafluoroethylene, surrounds the greater-in-diameter section 22. Referring to
Furthermore, at least one gas sealing ring 4 which is closely connected with both the greater-in-diameter section 22 and the outer shell 1 is provided for stopping gas flow. The gas sealing ring 4 is located at a position more than half a length of the greater-in-diameter section 22 from the rear end 20 of the greater-in-diameter section 22. Because there is constant friction between the gas sealing ring 4 and the outer shell 1 due to continuously vibration of the greater-in-diameter section 22, in this embodiment, there are two gas sealing rings 4 provided on the greater-in-diameter section 22 to enhance the stopping effect, avoiding the gas in the gas room 5 and the cylindrical gap 51 from leaking out. In this embodiment, as shown in
A stopper 23 is screwed in a central position of the rear end 20 of the greater-in-diameter section 22. The stopper 23 having a protruding portion 231 extending toward the gas room 5. The protruding portion 231 is sleeved with a spring 232 with one end abutting against the stopper 23 and an opposite end abutting against a recess 15 provided at the bottom end of the outer shell 1. The spring 232 is not aligned with the gas inlet channel 11. A first gas channel 24 communicating the gas room 5 and an inner space 25 of the inner tube member 2 is disposed in the inner tube member 2. A hammer member 6 capable of moving between a front position and a back position is provided in the inner space 25. A second gas channel 61 which is formed in T shape is disposed in the hammer member 6. When the hammer member 6 comes to the back position as shown in
A front shell 7 is fixed at a front end of the outer shell 1 by threads 16, 70. The less-in-diameter section 21 of the inner tube member 2 is sleeved with a cushion member 8 abutted against both the front shell 7 and the step portion 26. The cushion member 8 is a rubber chunk or a spring to cushion vibration by deformation. In this embodiment, a front teeth portion 811 is disposed at a front end 81 of the cushion member 8 while a rear teeth portion 821 is disposed at a rear end 82 of the cushion member 8. The front teeth portion 811 and the rear teeth portion 821 are staggered for the cushion member 8 being deformed more easily to cushion vibration.
A tool portion 71 and an impacted portion 72 connected with the tool portion 71 are provided in the front shell 7. The tool portion 71 can be changed for other use. The impacted portion 72 engages with the tool portion 71 to be hit by the hammer member 6 and transports the impact force to the tool portion 71.
Extending directions of the outer shell 1, the inner tube member 2, the gas inlet channel 11 and the first gas channel 24 are all parallel to the moving direction of the hammer member 6, which makes the whole impact tool straight.
After high pressure gas is guided through the gas inlet channel 11, the gas room 5 and the first gas channel 24 in sequence and is injected into the inner space 25, the hammer member 6 is driven to move back and forth to hit the impacted portion 72 so that the tool portion 71 works. In the meanwhile, the inner tube member 2 vibrates. However in the present invention, when high pressure gas is guided into the gas room 5, the cylindrical gap 51 between the outer shell 1 and the inner tube member 2 is filled. Therefore, high pressure gas in the gas room 5 and the cylindrical gap 51 generates a holding force functioning on the inner tube member 2 to reduce vibration.
On the other hand, there is no shaking, as hard bodies hit each other, when gas suffers compression since gas is formless material. Moreover, the gas room 5 and the cylindrical gap 51 are filled with high pressure gas so that the gas functions on the greater-in-diameter section 22 uniformly to take the best effect upon vibration reducing.
