JP2010228010A - Drive machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a trouble in feeding a nail caused by the bounding of a piston when the piston collides with a head bumper at a top dead center. <P>SOLUTION: A drive machine has a housing; a pressure storage chamber for storing compressed air that is arranged in the housing; a cylinder communicable with the pressure storage chamber; the piston arranged to be reciprocally movable in the cylinder; a return air chamber for storing pressure allowing the piston to be raised to the top dead center; and the head bumper positioned above the piston and absorbing surplus energy when the piston is raised to the top dead center. A shock absorbing member having hardness lower than that of the head bumper is arranged above the head bumper. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a shock-absorbing mechanism for a power tool, and more particularly to a shock-absorbing mechanism for absorbing an impact caused by driving of a piston such as a nail driver by a bumper.

  2. Description of the Related Art A driving machine for driving a stopper into a material to be driven using air or gas as a power source is known. The structure of a conventional driving machine will be described with reference to FIGS.

  The driving machine of FIG. 3 includes a cylinder 4 in a housing 2 and drives a stopper 15 into a driven material by a driver blade 21 integrally coupled to a piston 6 slidably received in the cylinder 4. A return air chamber 19 for storing air for returning the piston 6 to the initial position is formed by the outer periphery of the cylinder 4 and the housing 2, and an injection portion 3 including an injection port 13 through which a stopper 15 is driven is provided below the housing 2. In addition, the injection unit 3 includes a feeder (not shown) for feeding the stopper 15 to the injection port 13. In a general pneumatic tool, a bumper 7 and a head bumper 8 made of an elastic body are provided above and below the cylinder, and the surplus energy when the stopper is driven is absorbed by the bumper 7 and the surplus when the piston 6 returns to the initial position. Energy is absorbed by the head bumper 8.

  A driving machine provided with a head bumper is known as shown in the nailing machine of Patent Document 1. In addition, there is a piston made of an elastic material like a screw driving machine as shown in FIG. 3, and in this case, there is no head bumper and the piston itself is a buffer member.

JP 2007-331047 A

  The buffer mechanism of the driving machine of the above-mentioned Patent Document 1 greatly deflects the bumper in order to absorb the impact caused by the piston. The bumper, which is an elastic body, bends and then returns to its original shape due to elasticity. At this time, energy that the bumper tries to return to the original shape is transmitted to the piston, and the piston may bounce.

  However, in the conventional driving machine, the piston 6 gives an impact to the head bumper 8 in the return stroke. The piston 6 may bounce after the piston 6 collides with the head bumper 8 and the head bumper 8 bends. At this time, the driver blade 21 coupled to the piston 6 is pinched by the stopper 15 that has advanced into the injection port 6A to be driven next, and the piston 6 cannot return to the initial position. The stop 15 may not be driven.

  The object of the present invention is to eliminate the above-mentioned conventional drawbacks and to solve the failure of feeding of the stopper caused by the driver blade not returning to the initial position.

  The object is to provide a housing, a pressure accumulating chamber for storing compressed air provided in the housing, a cylinder capable of communicating with the pressure accumulating chamber, a piston provided for reciprocating movement in the cylinder, and In a driving machine having a return air chamber for storing a pressure to rise to a dead center, and a head bumper that is located above the piston and absorbs surplus energy when the piston rises to a top dead center. This can be achieved by providing a cushioning member having a hardness lower than that of the head bumper above the head bumper.

According to the present invention, by providing a buffer member having a hardness lower than that of the head bumper above the head bumper, it is possible to alleviate the impact in the return process of the piston, suppress the bounce of the piston, and reduce the nail feed failure. .

Sectional drawing which shows embodiment of the driving machine of this invention. Sectional drawing which shows other embodiment of the driving machine of this invention. Sectional drawing which shows the conventional driving machine. Sectional drawing which shows the conventional driving machine.

  The configuration of the driving machine according to the present invention will be described with reference to FIGS. For convenience of explanation, the upper direction in the drawing is defined as the upper direction and the lower direction in the drawing is defined as the lower direction. However, this definition does not limit the present invention.

  As shown in FIG. 1, the driving machine 1 mainly includes a housing 2 and an injection unit 3, and the housing 2 is integrally provided with a handle unit 2 </ b> A that extends in a direction intersecting an injection direction described later. In order to accumulate compressed air from a compressor (not shown), a pressure accumulating chamber 5 is formed in the handle portion 2 </ b> A of the driving machine 1 and the housing 2. An air plug for connecting an air hose extending from the compressor is provided at the end of the handle 2 </ b> A of the housing 2. The pressure accumulating chamber 5 is connected to a compressor (not shown) via an air hose (not shown).

  A cylindrical cylinder 4 is provided inside the housing 2, and a piston 6 that is slidable up and down is disposed in the cylinder 4. A rubber bumper 7 is disposed below the cylinder 4, and a head bumper 8 is disposed above the cylinder 4. An injection part 3 for driving a stopper is formed below the bumper 7.

  The cylinder 4 accommodates the piston 6 so as to be slidable up and down. A driver blade 21 for driving the stopper 15 is connected to the piston 6. The piston 6 has substantially the same outer peripheral surface as the inner periphery of the cylinder 4, and has an O-ring 9 as a seal member on the outer periphery of the piston 6, so that the cylinder 4 is separated by the piston 6 into an upper chamber of the cylinder 4 and a lower chamber of the cylinder 4. . The upper chamber of the cylinder 4 can be selectively communicated with the pressure accumulating chamber 5 and the atmosphere by operating the trigger 16. A cylinder plate 25 is provided on the outer periphery of the cylinder 4. The cylinder plate 25 has a hollow cylindrical shape, and an O-ring which is a seal member is provided on each of the inner periphery and the outer periphery thereof. The inner periphery of the cylinder plate 25 is substantially equal to the outer periphery of the cylinder 4, and the outer periphery of the cylinder plate 25 is approximately equal to the inner periphery of the housing 2. A return air chamber 19 is formed by the lower surface of the cylinder plate 25, the outer peripheral surface of the cylinder 4, and the inner wall of the housing 2. Air holes 17 and 18 are provided on the outer peripheral surface of the cylinder 4. Both the air holes 17 and 18 are provided so that the inside of the cylinder 4 and the return air chamber 19 communicate with each other, and the air hole 18 is located above the air hole 17. Further, the air hole 18 includes a check valve 20 that allows compressed air to flow only from the inside of the cylinder 4 toward the return air chamber 19.

  A cylindrical sleeve valve 10 </ b> A is provided above the cylinder 4. Since the inner peripheral surface of the sleeve valve 10A is substantially the same as the outer peripheral surface of the cylinder 4, the cylinder 4 is inserted into the sleeve valve 10A. A sleeve valve chamber 10B is formed by the lower end surface of the sleeve valve 10A, the outer peripheral surface of the cylinder 4, and the inner wall of the housing 2. A spring 11 is provided in the sleeve valve chamber 10B, and urges the sleeve valve 10A upward. The sleeve valve chamber 10B can selectively communicate with the pressure accumulating chamber 5 and the atmosphere via an air passage (not shown).

  A head bumper 8 is provided on the inner wall of the housing 2. The head bumper 8 has a cylindrical shape, and can be fixed by fitting the head bumper 8 into a protrusion formed on the inner wall of the housing 2. An upper buffer member 12 a is provided between the head bumper 8 and the inner wall of the housing 2. The upper buffer member 12a is a gel substance. Gels are characterized by higher heat dissipation than rubber. The upper buffer member 12a is a viscoelastic body having a higher viscosity than the head bumper 8 made of rubber. Further, the upper cushioning member 12 a is less elastic than the head bumper 8. Therefore, when the upper buffer member 12a receives an external force, the repulsive force is smaller than that of the head bumper 8, and the time for returning to the original shape is also slow. The upper buffer member 12a is formed in a sheet shape. The sheet-like upper cushioning member 12 a is formed to be thinner than the head bumper 8. The upper cushioning member 12 a is fixed by being sandwiched between the head bumper 8 and the inner wall of the housing 2. Therefore, since the upper buffer member 12a is formed in a sheet shape and is formed thinner than the thickness of the head bumper 8, the protrusion formed on the inner wall of the housing 2 can be shortened.

  The bumper 7 is located at the lower end in the cylinder 4, and the upper surface of the bumper 7 hits when the piston 6 reaches the bottom dead center. Since the bumper 7 is an elastic body made of rubber, the bumper 7 is deformed and absorbs surplus energy of the piston. A lower cushioning member 12b is provided between the bumper 7 and the injection portion 3. The bumper 7 and the lower buffer member 12b are provided adjacent to each other, and the lower surface of the bumper 7 and the lower buffer member 12b are in contact with each other.

  The injection unit 3 is located at the lower end of the bumper 7 and includes an injection port 13 and a magazine 14. The injection part forms an injection port 13 inside. The magazine 14 includes a feeding unit. The feeding unit includes a feed cylinder 26, a reciprocating shaft 27, and a feed claw 28. The feed cylinder 26 includes a feed piston therein, and a reciprocating shaft 27 is integrally provided on the feed piston. One end of the reciprocating shaft 27 is coupled to the feed piston, but a feed claw 28 is fixed to the other end by a pin (not shown). The inside of the feed cylinder 26 communicates with the return air chamber 19 described above. The feed piston inside the feed cylinder 26 is urged toward the injection port 13 by a spring (not shown).

  Next, the operation of the driving machine according to the present invention will be described with reference to FIG. When an air hose (not shown) is connected, a part of the compressed air accumulated in the pressure accumulating chamber 5 flows into the sleeve valve chamber 10B through an air passage (not shown). The sleeve valve 10 </ b> A is urged upward by the compressed air that has flowed into the sleeve valve chamber 10 </ b> B and the spring 11. In a state where the trigger 16 is not operated, the sleeve valve 10 </ b> A is urged downward by the compressed air in the pressure accumulating chamber 5. However, since the compressed air flowing into the sleeve valve chamber 10B and the upward biasing force by the spring 11 are stronger, the compressed air is prevented from flowing into the cylinder 4 upper chamber.

  When the trigger 16 is pulled, the sleeve valve chamber 10B communicates with the atmosphere. Thereby, the sleeve valve 10A moves downward, and the pressure accumulation chamber 5 and the cylinder 4 upper chamber communicate with each other. The compressed air flowing into the upper chamber of the cylinder 4 moves the piston 6 rapidly to the bottom dead center, and drives the stopper 15 by the driver blade 21 coupled to the piston 6. At this time, the air in the lower chamber of the cylinder 4 flows into the return air chamber 19 through the air hole 17. An air hole 18 provided with a check valve 20 that allows compressed air to flow only in the direction of the return air chamber 19 is provided on the side surface of the cylinder 4. Therefore, when the piston 6 is positioned below the air hole 18 provided in the cylinder 4, a part of the compressed air flowing into the upper chamber of the cylinder 4 flows into the return air chamber 19 through the air hole 18. The piston 6 lowered by the compressed air flowing in from the pressure accumulating chamber 5 contacts the bumper 7 at the bottom dead center. The bumper 7 absorbs excess energy of the piston 6 and deforms. Compared to the bumper 7, a lower buffer member 12 b that does not repel external force is provided between the bumper 7 and the injection unit 3. The surplus energy of the piston 6 received by the bumper 7 is transmitted to the lower buffer member 12b, and the lower buffer member 12b is deformed.

  The operation of the feeding unit of the magazine 14 will be described. During the driving process, part of the compressed air in the lower chamber of the cylinder 4 and the compressed air in the upper chamber of the cylinder 4 after the piston 6 passes through the air hole 18 flows into the return air chamber 19. Since the return air chamber 19 communicates with the feed cylinder 26, compressed air flows from the return air chamber 19 into the feed cylinder 26 when the stopper is driven. When compressed air flows into the feed cylinder 26, the feed piston moves in a direction away from the injection port 13 against the biasing force of the spring. At this time, the feeding claw 28 is caught by the next stopper.

  When the trigger 16 is returned, compressed air flows into the sleeve valve chamber 10B and pushes the sleeve valve 10A upward. Therefore, the upper chamber of the cylinder 4 and the pressure accumulating chamber 5 are shut off, and the upper chamber of the cylinder 4 and the atmosphere communicate. The piston 6 is pressed and raised from below by the compressed air accumulated in the return air chamber 19 and comes into contact with the head bumper 8 at the top dead center. The head bumper 8 absorbs excess energy of the piston 6 and deforms.

  Further, by returning the trigger 16, the compressed air in the return air chamber 19 returns to the inside of the cylinder 4 and is released to the atmosphere. Since there is no compressed air in the return air chamber 19, there is no compressed air flowing into the feed cylinder 26. Since the feed piston is always urged by the spring, the feed piston, the reciprocating shaft 27, and the feed claw 28 move in the direction of the injection port 13 when there is no compressed air in the feed cylinder 26. Since the piston 6 and the driver blade 21 are moved to the top dead center by the compressed air stored in the return air chamber 19, the injection blade 13 does not have the driver blade 21. Therefore, the next stopper hooked on the feed claw is sent to the injection port 13.

  An upper buffer member 12 a is provided between the head bumper 8 and the housing 2. Since the upper buffer member 12a is provided adjacent to the upper side of the head bumper 8, excess energy of the piston 6 received by the lower surface of the head bumper 8 is transferred from the upper surface of the head bumper 8 to the upper buffer member 12a, which is a sheet-like gel substance. It is transmitted to the lower surface. The upper buffer member 12a is a viscoelastic body having a strong viscosity property. Therefore, the upper buffer member 12 a is deformed by receiving the surplus energy of the piston 6, but the force for returning to the original shape is smaller than that of the head bumper 8. Thereby, the surplus energy at the top dead center of the piston 6 can be absorbed by the deformation of the head bumper 8 and the upper buffer member 12a. Furthermore, since the upper buffer member 12a is a highly viscous viscoelastic body, it receives a viscous resistance when deformed. The impact absorbed by the deformation of the upper cushioning member 12a is released as thermal energy by receiving viscous resistance when returning to its original shape. After the head bumper 8 and the upper buffer member 12a are bent, a part of the reaction energy when returning to the original shape is released as thermal energy, so that the reaction transmitted to the piston 6 can be reduced. This prevents the piston 6 from moving in the direction of the injection unit 3. If the piston 6 does not move in the direction of the injection portion 3, the driver blade 21 can be prevented from entering the injection port 13 before the feed claw 28 sends the next stopper to the injection port 13. In this way, the feeding failure of the stopper due to the driver blade 21 being sandwiched between the stoppers sent to the ejection port 13 by the feed claws 28 in the ejection port 13 is prevented.

  Another embodiment of the present invention is shown in FIG. FIG. 2 shows an example of a screw driving machine that is operated by compressed air and that is tightened simultaneously with a stopper 15 such as a screw. Members or elements having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

  The screw driving machine shown in FIG. 2 is divided into a piston (A) 22 made of an elastic body and a piston (B) 23 made of steel, and a driver bit 24 is coupled to the piston (A) 22. . The piston (A) 22 and the piston (B) 23 are provided so as to be able to reciprocate in the cylinder 4 and have a return air chamber 19 for storing pressure for returning the piston to the top dead center. On the upper surface of the piston (A) 22, an upper buffer member 12a is provided adjacently.

The embodiment of the present invention has been described above. The present invention is not limited to this embodiment, and can be changed without departing from the content of the invention. For example, in the embodiment of the screw driving machine of FIG. 2, the buffer member 12a is provided adjacent to the upper surface of the piston (A) 22, but may be provided on the surface where the upper surface of the piston (A) 22 abuts at the top dead center.

1: Driving machine 2: Housing 2A: Handle part 3: Injection part 4: Cylinder 5: Accumulation chamber 6: Piston 7: Bumper 8: Head bumper 9: O-ring 10A: Sleeve valve 10B: Sleeve valve chamber 11: Spring 12a: Upper buffer member 12b: Lower buffer member 13: Injection port 14: Magazine 15: Stopper 16: Trigger 17: Air hole 18: Air hole 19: Return air chamber 20: Check valve 21: Driver blade 22: Piston (A )
23: Piston (B) 24: Driver bit 25: Cylinder plate 26: Feed cylinder 27: Reciprocating shaft 28: Feed claw

Claims (1)

A housing;
A pressure accumulating chamber for storing compressed air provided inside the housing;
A cylinder capable of communicating with the pressure accumulating chamber;
A piston provided so as to be capable of reciprocating in the cylinder;
A return air chamber for storing pressure for the piston to rise to top dead center;
A head bumper that is located above the piston and absorbs surplus energy when the piston rises to top dead center;
A driving machine characterized in that a cushioning member having a hardness lower than that of the head bumper is provided above the head bumper.

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