EP3960378A1

EP3960378A1 - Pneumatic tool

Info

Publication number: EP3960378A1
Application number: EP20796117.8A
Authority: EP
Inventors: Hiroshi Tanaka
Original assignee: Max Co Ltd
Current assignee: Max Co Ltd
Priority date: 2019-04-26
Filing date: 2020-04-24
Publication date: 2022-03-02
Also published as: TW202100311A; WO2020218545A1; JP2020182983A; TWI833948B; EP3960378A4; JP7222304B2

Abstract

A pneumatic tool (1A) includes a chamber (70) having a predetermined volume to which compressed air is supplied, a control valve (8) connected to the chamber (70) and configured to switch actuation and non-actuation of a to-be-controlled object (3), and an adjustment mechanism configured to switch actuation of the control valve (8).

Description

TECHNICAL FIELD

The present invention relates to a pneumatic tool configured to be actuated by using compressed air as a power source.

BACKGROUND ART

Known is a pneumatic tool called a nailing machine configured to reciprocally move a striking piston by using compressed air as a power source, thereby driving a driver coupled to the striking piston to strike a nail or the like supplied to a nose. In such nailing machine, a head valve is actuated to strike a nail by two operations, one operation of pulling a trigger provided on a grip part and other operation of pressing a contact arm protruding from a tip end of a nose and provided to be reciprocally movable against a material to be struck.
In descriptions below, a state where the trigger is pulled by one operation is referred to as 'trigger ON', and a state where one operation is released and the trigger is not pulled is referred to as 'trigger OFF'. In addition, a state where the contact arm is pressed by the other operation is referred to as 'contact arm ON', and a state where the other operation is released and the contact arm is not pressed is referred to as 'contact arm OFF'.
In the nailing machine, for example, after setting the contact arm ON, when the trigger is set to the trigger ON in a state of the contact arm ON, the head valve is actuated to strike a nail.
Suggested is a technology where after striking the nail, when the contact arm is set to the contact arm OFF in the state of the trigger ON and the contact arm is again set to the contact arm ON in the state of the trigger ON, the head valve is actuated to strike a next nail. In this way, an operation of continuously striking nails by repeating the contact arm ON and the contact arm OFF in the state of the trigger ON is referred to as 'contact striking'.
In the contact striking, after striking a nail, nails can be continuously struck each time the contact arm ON is set in the state of the trigger ON, which is suitable for a quick operation. On the other hand, suggested is a technology where when a predetermined time elapses without setting of the contact arm ON after the trigger ON is set, the head valve is put into non-actuation, so as to regulate a careless operation (refer to PTL 1).

CITATION LIST

PATENT LITERATURE

PTL 1: Japanese examined utility model application publication No. H06-32308

SUMMARY OF INVENTION

TECHNICAL PROBLEM

In the configuration where when a predetermined time elapses without setting of the contact arm ON after the trigger ON is set, the head valve is put into the non-actuation, when the elapse of the predetermined time is measured by an electrical timer, the time measurement can be stably performed. However, the nailing machine configured to be driven by the compressed air does not have a supply source of electricity. For this reason, in order to use the electrical timer, a power supply and a circuit are required.
Regarding this, PTL 1 suggests a time measurement mechanism using a pressure of compressed air in a main chamber in which the compressed air for actuating the nailing machine is reserved. The time measurement mechanism using the air pressure has a configuration where the compressed air is supplied from the main chamber to a space having a predetermined volume, and when the space reaches a predetermined pressure, a valve is actuated by the air pressure, for example.
In such time measurement mechanism, a power supply and a circuit are not required. However, the pressure of the compressed air that is supplied from a compressor (not shown) is not always constant, and the pressure in the main chamber varies due to an influence of consumption of the compressed air in the main chamber resulting from a nail striking-out operation and the like. As a result, a time consumed until the space reaches a predetermined pressure for actuating the valve is not constant. For this reason, in the nailing machine to which the time measurement mechanism using the air pressure is applied, it is difficult to stably perform the time measurement, and the time after the trigger is pulled until the head valve is put into the non-actuation is not constant.
An object of the present invention is to provide a pneumatic tool capable of stably performing time measurement and stably switching execution and non-execution of a contact striking, irrespective of variation factors such as an air pressure.

SOLUTION TO PROBLEM

The present invention is a pneumatic tool including a chamber having a predetermined volume to which compressed air is supplied, a control valve connected to the chamber and configured to switch actuation and non-actuation of a to-be-controlled object, and an adjustment mechanism configured to switch actuation of the control valve.

ADVANTAGEOUS EFFECTS OF INVENTION

In the present invention, it is possible to provide the pneumatic tool capable of stably performing time measurement and stably switching execution and non-execution of a contact striking, irrespective of variation factors such as an air pressure.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] FIG. 1 is a side sectional view showing an example of a nailing machine.
[FIG. 2A] FIG. 2A is a sectional view showing an example of a head valve.
[FIG. 2B] FIG. 2B is a sectional view showing the example of the head valve.
[FIG. 3A] FIG. 3A is a sectional view showing an example of a trigger valve and a switch valve.
[FIG. 3B] FIG. 3B is a sectional view showing the example of the trigger valve and the switch valve.
[FIG. 3C] FIG. 3C is a sectional view showing the example of the trigger valve and the switch valve.
[FIG. 3D] FIG. 3D is a sectional view showing the example of the trigger valve and the switch valve.
[FIG. 4A] FIG. 4A is a sectional view showing an example of a timer chamber.
[FIG. 4B] FIG. 4B is a sectional view showing the example of the timer chamber.
[FIG. 5A] FIG. 5A is a sectional view showing an example of a control valve.
[FIG. 5B] FIG. 5B is a sectional view showing the example of the control valve.
[FIG. 6A] FIG. 6A is a sectional view showing an example of an operation of the nailing machine.
[FIG. 6B] FIG. 6B is a sectional view showing the example of the operation of the nailing machine.
[FIG. 6C] FIG. 6C is a sectional view showing the example of the operation of the nailing machine.
[FIG. 6D] FIG. 6D is a sectional view showing the example of the operation of the nailing machine.
[FIG. 7A] FIG. 7A is a sectional view showing an example of an operation of the nailing machine where the control valve is actuated.
[FIG. 7B] FIG. 7B is a sectional view showing the example of the operation of the nailing machine where the control valve is actuated.
[FIG. 8A] FIG. 8A is a sectional view showing an example of a nailing machine of a first embodiment.
[FIG. 8B] FIG. 8B is a sectional view showing the example of the nailing machine of the first embodiment.
[FIG. 9A] FIG. 9A is a sectional view showing an example of a nailing machine of a second embodiment.
[FIG. 9B] FIG. 9B is a sectional view showing the example of the nailing machine of the second embodiment.
[FIG. 10A] FIG. 10A is a sectional view showing an example of a nailing machine of a third embodiment.
[FIG. 10B] FIG. 10B is a sectional view showing the example of the nailing machine of the third embodiment.
[FIG. 11A] FIG. 11A is a sectional view showing an example of a nailing machine of a fourth embodiment.
[FIG. 11B] FIG. 11B is a sectional view showing the example of the nailing machine of the fourth embodiment.
[FIG. 12A] FIG. 12A is a sectional view showing an example of a nailing machine of a fifth embodiment.
[FIG. 12B] FIG. 12B is a sectional view showing the example of the nailing machine of the fifth embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a nailing machine as a striking tool that is an example of the pneumatic tool of the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view showing an example of a nailing machine. FIG. 1 shows a state in which a striking piston is located at a top dead center.
A nailing machine 1 has a striking cylinder 2 in a main body 10. In the striking cylinder 2, a striking piston 20 is slidably provided. A striking driver 21 as a nail striking-out member protruding from a lower surface-side is fixed to the striking piston 20, and the striking piston 20 and the striking driver 21 are configured to integrally move. In addition, an O-ring 20a as a sealing member is attached to an outer periphery of the striking piston 20.
The nailing machine 1 has a nose 11 at a lower end portion of the main body 10. The nose 11 has an ejection hole 11a formed to guide the striking driver 21 and provided coaxially with the striking cylinder 2.
The nailing machine 1 has a main chamber 13 in which compressed air supplied to an inside of a grip part 12 of the main body 10 and a circumferential part of the striking cylinder 2 is reserved. The striking piston 20 of the nailing machine 1 is driven by the compressed air that is supplied to the striking cylinder 2. The compressed air for driving the striking piston 20 is supplied from the main chamber 13 to the striking cylinder 2.
The nailing machine 1 has a return air chamber 14 on an outer periphery-side of the striking cylinder 2, independently of the main chamber 13. The striking cylinder 2 has a plurality of radial small holes 14a at a substantially middle part in an axial direction, the small holes 14a and the return air chamber 14 are configured to communicate via a check valve 14b.
The striking cylinder 2 has a striking piston stopper 22 at an upper end portion. The striking piston stopper 22 protrudes from the upper end portion of the striking cylinder 2 toward an inner periphery-side, and is in contact with the striking piston 20 returned to the top dead center. In addition, the striking piston stopper 22 opens at a center of the upper end portion of the striking cylinder 2. Thereby, the striking cylinder 2 is formed at the center of the upper end portion with an air supply/exhaust port 22a through which the compressed air supplied from the main chamber 13 passes.
The striking cylinder 2 has a concave portion 22b on an inner peripheral surface near the upper end portion that faces the O-ring 20a of the striking cylinder 20 in a state where the striking piston 20 is located at the top dead center. When the striking piston 20 returns to the top dead center, the O-ring 20a of the striking piston 20 enters the concave portion 22b of the striking cylinder 2, so that a gap is generated between the O-ring 20a and the concave portion 22b and an air for returning the striking piston 20 is discharged from the gap. As a result, the drive force of the striking piston 20 is lost. Thereby, the striking piston 20 is stopped at the top dead center.
FIGS. 2A and 2B are sectional views showing an example of a head valve. The nailing machine 1 has a head valve 3 at the upper end portion of the striking cylinder 2. The head valve 3 is an example of the to-be-controlled object, and has a head valve cylinder 30 configured to form a cylindrical space at an upper end part of the main body 10, and a head valve piston 31 is slidably attached in the head valve cylinder 30.
The head valve 3 has a head valve piston stopper 32 at an upper part of the head valve piston 31. The head valve piston 31 is provided between the head valve piston stopper 32 and the striking piston stopper 22, and is urged toward the striking piston stopper 22, which is a direction of a bottom dead center, by a spring 33.
The head valve piston 31 is formed to have a shape to close between the main chamber 13 and the air supply/exhaust port 22a of the striking piston stopper 22 by coming into contact with the striking piston stopper 22. In addition, the head valve piston 31 has an air exhaust port opening/closing portion 31a having an opening configured to communicate with the air supply/exhaust port 22a of the striking piston stopper 22 by coming into contact with the striking piston stopper 22.
The head valve piston 31 is configured so that the air exhaust port opening/closing portion 31a enters the center opening of the head valve piston stopper 32 to open/close between an air exhaust port 15 provided on the upper end portion-side of the main body 10 and the air supply/exhaust port 22a of the striking piston stopper 22.
The head valve 3 has a head valve upper chamber 34 formed between the head valve piston 31 and the head valve piston stopper 32. The head valve upper chamber 34 is configured to communicate with a trigger valve 5 or the main chamber 13 via a control valve 8, which will be described later. In addition, the head valve upper chamber 34 is configured to communicate with the main chamber 13 or the atmosphere via the trigger valve 5.
FIG. 2A shows a state where the head valve piston 31 is moved to the bottom dead center that is a standby position in the head valve 3. In the state where the head valve piston 31 is moved to the bottom dead center, the head valve piston 31 comes into contact with the striking piston stopper 22 to close between the main chamber 13 and the air supply/exhaust port 22a of the striking piston stopper 22. Thereby, the compressed air is not supplied from the main chamber 13 to the striking cylinder 2.
In addition, the head valve upper chamber 34 is formed between the head valve piston 31 and the head valve piston stopper 32. Further, the air exhaust port opening/closing portion 31a of the head valve piston 31 descends into the center opening of the head valve piston stopper 32 to open between the air exhaust port 15 and the air supply/exhaust port 22a of the striking piston stopper 22. Thereby, a space in the striking cylinder 2 above the striking piston 20 communicates with the atmosphere.
FIG. 2B shows a state where the head valve piston 31 is moved to the top dead center that is an actuation position in the head valve 3. In the state where the head valve piston 31 is moved to the top dead center, the head valve piston 31 comes into contact with the head valve piston stopper 32 to open between the main chamber 13 and the air supply/exhaust port 22a of the striking piston stopper 22. Thereby, the compressed air is supplied from the main chamber 13 to the striking cylinder 2 through the air supply/exhaust port 22a.
In addition, the air exhaust port opening/closing portion 31a of the head valve piston 31 protrudes into the air exhaust port 15 from the center opening of the head valve piston stopper 32, so that a tip end of the air exhaust port opening/closing portion 31a comes into contact with a head valve seal 35, which is a seal member provided above the head valve 3, to close between the air exhaust port 15 and the air supply/exhaust port 22a of the striking piston stopper 22. Thereby, the compressed air supplied from the main chamber 13 to the striking cylinder 2 is not exhausted from the air exhaust port 15.
As shown in FIG. 1, the nailing machine 1 has a trigger lever 4 and a contact arm 40. The trigger lever 4 has a large lever 42 rotatably attached to the main body 10 via a shaft 41, and a small lever 44 rotatably attached to the large lever 42 via a shaft 43.
The contact arm 40 is connected to a pressing member 40a. The pressing member 40a is in contact with the small lever 44, and the contact arm 40 is attached to be reciprocally movable along an axial direction (upper and lower direction) of the nose 11 via a compression spring 40b. In addition, the contact arm 40 is urged by the compression spring 40b so as to further protrude than a tip end of the nose 11, and is configured to rotate upward the small lever 44 by pressing a tip end portion of the contact arm 40 against a target object.
FIGS. 3A, 3B, 3C and 3D are sectional views showing an example of a trigger valve and a switch valve. The nailing machine 1 has a trigger valve 5 on an inner side of a base end portion of the grip part 12. The trigger valve 5 is configured to be pressed to send an actuation signal to the head valve 3 by the small lever 44.
The trigger valve 5 has a housing 51 in which a passage 50 configured to communicate with the head valve upper chamber 34 via the control valve 8, which will be described later, is formed, and a pilot valve 52 attached to the housing 51 so as to be vertically movable. The trigger valve 5 also has a trigger valve stem 54 attached so as to appear and disappear from an inside of the pilot valve 52 with respect to a cap 53, and a spring 55 provided between the pilot valve 52 and the trigger valve stem 54 and configured to press downward the trigger valve stem 54. In addition, the trigger valve 5 has a passage 56 configured to communicate with the atmosphere.
In the trigger valve 5, a gap S1 is formed between the pilot valve 52 and the housing 51, a gap S2 is formed between the pilot valve 52 and the trigger valve stem 54, and a gap S3 is formed between the trigger valve stem 54 and the cap 53. In addition, an empty chamber 53a is formed between the pilot valve 52 and the cap 53.
The pilot valve 52 has an O-ring 52a configured to open/close the gap S1 with respect to the main chamber 13 and an O-ring 52b configured to open/close between the passage 50 and the passage 56 and to communicate the passage 50 and the atmosphere via the passage 56, according to a position of the pilot valve 52 relative to the housing 51. The pilot valve 52 also has an O-ring 52c configured to seal between the empty chamber 53a and the passage 56. The pilot valve 52 also has a passage 52d configured to communicate with the main chamber 13.
The trigger valve stem 54 has an O-ring 54a configured to open/close the gap S2 with respect to the main chamber 13 and an O-ring 54b configured to open/close the gap S3 with respect to the atmosphere, according to positions of the pilot valve 52 and the trigger valve stem 54 relative to the housing 51 and the cap 53.
FIGS. 3A and 3B show a state where the pilot valve 52 is moved to the standby position and the trigger valve stem 54 is moved to the standby position in the trigger valve 5. In the state where the pilot valve 52 is moved to the standby position in the trigger valve 5, the O-ring 52b of the pilot valve 52 is configured to come into contact with the housing 51, so that the passage 50 is closed with respect to the passage 56. On the other hand, the O-ring 52a of the pilot valve 52 is configured to separate from the housing 51 to open the gap S1, so that the passage 50 communicates with the main chamber 13 via the gap S1.
In addition, in the state where the trigger valve stem 54 is moved to the standby position in the trigger valve 5, the O-ring 54b of the trigger valve stem 54 is configured to come into contact with the housing 53, so that the gap S3 is closed. On the other hand, the O-ring 54a of the trigger valve stem 54 is configured to separate from the pilot valve 52 to open the gap S2, so that the empty chamber 53a communicates with the main chamber 13 via the passage 52d and the gap S2.
FIG. 3C shows a state where the pilot valve 52 is moved to the standby position and the trigger valve stem 54 is moved to the actuation position in the trigger valve 5. In the state where the trigger valve stem 54 is moved to the actuation position in the trigger valve 5, the O-ring 54a of the trigger valve stem 54 is configured to come into contact with the pilot valve 52, so that the gap S2 is closed. On the other hand, the O-ring 54b of the trigger valve stem 54 is configured to separate from the cap 53 to open the gap S3, so that the empty chamber 53a communicates with the atmosphere via the gap S3.
FIG. 3D shows a state where the pilot valve 52 is moved to the actuation position and the trigger valve stem 54 is moved to the actuation position in the trigger valve 5. In the state where the pilot valve 52 is moved to the actuation position in the trigger valve 5, the pilot valve 52 is configured to come into contact with the cap 53, so that the empty chamber 53a is not formed. In addition, the O-ring 52a of the pilot valve 52 is configured to come into contact with the housing 51, so that the gap S1 is closed. On the other hand, the O-ring 52b of the pilot valve 52 is configured to separate from the housing 51, so that the passage 50 and the passage 56 open therebetween and the passage 50 communicate s with the atmosphere via the passage 56.
The nailing machine 1 has a switch valve 6 alongside the trigger valve 5. The switch valve 6 has a cylinder 60, a switch valve stem 61 configured to reciprocally move in the cylinder 60, and a spring 62 for urging downward the switch valve stem 61. A lower end of the switch valve stem 61 is in contact with the large lever 42 by urging of the spring 62, and the switch valve 6 is configured to be actuated by a pull-up operation of the large lever 42.
The switch valve 6 has passages 63 and 64 formed between the cylinder 60 and the switch valve stem 61. In the switch valve 6, the passage 63 is configured to communicate with the main chamber 13 via a throttle 63a and the passage 64 is configured to communicate with the atmosphere via a passage 64a. In addition, in the switch valve 6, the passage 63 or the passage 64 is configured to communicate with a timer chamber 7, which will be described later, via a passage 65.
The switch valve stem 61 has an O-ring 61a configured to open/close between the passage 63 and the passage 65, and an O-ring 61b configured to open/close the passage 64a.
A state where the switch valve stem 61 is moved to the standby position in the switch valve 6 is shown in FIG. 3A. In the state where the switch valve stem 61 is moved to the standby position in the switch valve 6, the passage 63 and the passage 65 are configured to be closed therebetween by the O-ring 61a, so that the main chamber 13 does not communicate with the timer chamber 7 via the passage 65. On the other hand, the O-ring 61b is configured to open the passage 64a, so that the timer chamber 7 communicates with the atmosphere via the passage 64a, the passage 64 and the passage 65.
FIGS. 3B to 3D show a state where the switch valve stem 61 is moved to the actuation position in the switch valve 6. In the state where the switch valve stem 61 is moved to the actuation position in the switch valve 6, the passage 64a is configured to be closed by the O-ring 61b, so that the timer chamber 7 does not communicate with the atmosphere via the passage 64 and the passage 65. On the other hand, the passage 63 and the passage 65 are configured to be opened therebetween by the O-ring 61a, so that the main chamber 13 communicates with the timer chamber 7 via the throttle 63a, the passage 63 and the passage 65.
FIGS. 4A and 4B are sectional views showing an example of a timer chamber. The nailing machine 1 has the timer chamber 7. The timer chamber 7 has a chamber 70, a reset valve 71 configured to open the chamber 70 to the atmosphere, and a spring 72 for urging the reset valve 71.
The chamber 70 has a predetermined volume and has an air inlet 70a configured to communicate with the passage 65 of the switch valve 6 and an air outlet 70b configured to communicate with a control valve 8, which will be described later.
The reset valve 71 has a cylinder 71a, and a piston 71b configured to reciprocally move in the cylinder 71a. In the reset valve 71, the cylinder 71a is configured to communicate with the return air chamber 14 and the piston 71b is configured to be pressed by air supplied from the return air chamber 14.
The reset valve 71 has an O-ring 71c configured to open/close a passage 70d configured to communicate with an air exhaust port 70c of the chamber 70.
FIG. 4A shows a state where the reset valve 71 is moved to the standby position in the timer chamber 7. In the state where the reset valve 71 is moved to the standby position in the timer chamber 7, the passage 70d is configured to be closed by the O-ring 71c, so that the chamber 70 does not communicate with the atmosphere via the air exhaust port 70c.
FIG. 4B shows a state where the reset valve 71 is moved to the actuation position in the timer chamber 7. In the state where the reset valve 71 is moved to the actuation position in the timer chamber 7, the O-ring 71c is configured to open the passage 70d, so that the chamber 70 communicates with the atmosphere via the passage 70d and the air exhaust port 70c.
FIGS. 5A and 5B are sectional views showing an example of a control valve. The nailing machine 1 has a control valve 8. The control valve 8 has a cylinder 80, a piston 81 that is an actuation member configured to reciprocally move in the cylinder 80, and a spring 82 for urging the piston 81. The control valve 8 also has a cylinder 83, a control valve stem 84 configured to be pressed by the piston 81 and to reciprocally move in the cylinder 83, and a spring 85 for urging the control valve stem 84 toward the piston 81.
In the control valve 8, the cylinder 80 is configured to communicate with the outlet 70b of the timer chamber 7 and the piston 81 is configured to be pressed by air supplied from the timer chamber 7.
The control valve 8 has passages 86 and 87 formed between the cylinder 83 and the control valve stem 84. In the control valve 8, the passage 86 is configured to communicate with the passage 50 of the trigger valve 5 and the passage 87 is configured to communicate with the main chamber 13.
The control valve stem 84 has an O-ring 84a configured to open/close between the head valve upper chamber 34 and the passage 86, and an O-ring 84b configured to open/close between the head valve upper chamber 34 and the passage 87.
FIG. 5A shows a state where the piston 81 and the control valve stem 84 are moved to the standby position in the control valve 8. In the state where the piston 81 is moved to the standby position in the control valve 8, the control valve stem 84 is moved to the standby position. In the state where the control valve stem 84 is moved to the standby position in the control valve 8, the O-ring 84a is configured to open the passage 86, so that the head valve upper chamber 34 communicates with the passage 50 of the trigger valve 5 via the passage 86. On the other hand, the passage 87 is configured to be closed by the O-ring 84b, so that the head valve upper chamber 34 does not communicate with the main chamber 13 via the passage 87.
FIG. 5B shows a state where the piston 81 and the control valve stem 84 are moved to the actuation position in the control valve 8. In the state where the piston 81 is moved to the actuation position in the control valve 8, the control valve stem 84 is moved to the actuation position. In the state where the control valve stem 84 is moved to the actuation position in the control valve 8, the passage 86 is configured to be closed by the O-ring 84a, so that the head valve upper chamber 34 does not communicate with the passage 50 of the trigger valve 5 via the passage 86. On the other hand, the passage 87 is configured to be opened by the O-ring 84b, so that the head valve upper chamber 34 communicates with the main chamber 13 via the passage 07.

FIGS. 6A to 6D are sectional views showing an example of an operation of the nailing machine. Subsequently, the operation of the nailing machine 1 is described. In following operations, an operation called a contact striking of pressing the contact arm 40 against a target object in a state where the trigger lever 4 is pulled is described.
When an air hose (not shown) is connected, the main chamber 13 is filled with the air. As shown in FIG. 6A, in an OFF state where the trigger lever 4 is not operated, the pilot valve 52 and the trigger valve stem 54 of the trigger valve 5 are in the standby position described in FIG. 3A and the switch valve stem 61 of the switch valve 6 is in the standby position until the trigger lever 4 is operated and becomes in an ON state. In addition, the reset valve 71 of the timer chamber 7 is in the standby position described in FIG. 4A, and the piston 81 and the control valve stem 84 of the control valve 8 are in the standby position described in FIG. 5A. Further, the head valve piston 31 of the head valve 3 is in the standby position described in FIG. 2A.
In the state where the trigger valve stem 54 of the trigger valve 5 is in the standby position described in FIG. 3A, the compressed air is supplied from the main chamber 13 to the empty chamber 53a of the trigger valve 5 and the pilot valve 52 is maintained in the state of moving to the standby position. Thereby, the gap S1 of the trigger valve 5 opens, so that the main chamber 13 and the passage 50 communicate. On the other hand, the passage 50 does not communicate with the atmosphere via the passage 56.
In addition, in the state where the switch valve stem 61 of the switch valve 6 is in the standby position shown in FIG. 3A, the passage 64 opens. Thereby, the chamber 70 of the timer chamber 7 communicates with the atmosphere via the passage 64 of the switch valve 6. The chamber 70 is put into the atmospheric pressure, so that the piston 81 and the control valve stem 84 of the control valve 8 are maintained in the state of moving to the standby position described in FIG. 5A.
In the state where the piston 81 and the control valve stem 84 of the control valve 8 are located in the standby position, the passage 86 of the control valve 8 opens. Thereby, the compressed air is supplied from the main chamber 13 to the head valve upper chamber 34 via the passage 50 of the trigger valve 5 and the passage 86 of the control valve 8, so that the head valve piston 31 is moved to the bottom dead center, which is the standby position, by the pressure of the compressed air and the urging of the spring 33. Therefore, the compressed air is not supplied from the main chamber 13 to the striking cylinder 2.
As shown in FIG. 6B, when the trigger lever 4 is pulled and becomes in an ON state, the switch valve stem 61 of the switch valve 6 is moved from the standby position to the actuation position described in FIG. 3B.
When the switch valve stem 61 is moved to the actuation position in the switch valve 6, the passage 64 is closed, so that the timer chamber 7 does not communicate with the atmosphere via the passage 64. On the other hand, the passage 63 opens, so that the main chamber 13 communicates with the timer chamber 7 via the throttle 63a and the passage 63.
Thereby, the compressed air whose flow rate is restricted by the throttle 63a is caused to flow into the chamber 70 of the timer chamber 7 via the passage 63. Therefore, the pressure in the chamber 70 of the timer chamber 7 starts to rise.
As shown in FIG. 6C, in the ON state where the trigger lever 4 is pulled, when the tip end portion of the contact arm 40 is pressed against the target object and the contact arm becomes in an ON state, the small lever 44 is rotated upward, the trigger valve stem 54 of the trigger valve 5 is pushed and the trigger valve stem 54 is moved from the standby position to the actuation position described in FIG. 3C.
In the state where the trigger valve stem 54 is moved to the actuation position, the gap S2 of the trigger valve 5 is closed. Thereby, the compressed air from the main chamber 13 is not caused to flow into the empty chamber 53a.
On the other hand, the empty chamber 53a communicates with the atmosphere via the gap S3. Thereby, the inside of the empty chamber 53a is put into the atmospheric pressure and the pilot valve 52 is pushed by the pressure in the main chamber 13, so that the pilot valve 52 is moved from the standby position to the actuation position described in FIG. 3D.
In the state where the pilot valve 52 is moved to the actuation position, the gap S1 of the trigger valve 5 is closed. On the other hand, the passage 50 and the passage 56 are opened therebetween, so that the passage 50 communicates with the atmosphere via the passage 56.
In the control valve 8, in the state where the piston 81 and the control valve stem 84 are in the standby position described in FIG. 5A, the head valve upper chamber 34 communicates with the passage 50 of the trigger valve 5 via the passage 86. On the other hand, the passage 87 is closed, so that the head valve upper chamber 34 does not communicate with the main chamber 13 via the passage 87.
Thereby, when the pilot valve 52 is moved to the actuation position, the head valve upper chamber 34 is put into the atmospheric pressure and the head valve piston 31 is pushed by the pressure in the main chamber 13, so that the head valve piston 31 is moved from the standby position to the top dead center that is the actuation position described in FIG. 2B.
When the head valve piston 31 is moved to the top dead center, the head valve piston 31 comes into contact with the head valve piston stopper 32 to open between the main chamber 13 and the air supply/exhaust port 22a of the striking piston stopper 22. Thereby, the compressed air is supplied from the main chamber 13 to the striking cylinder 2 through the air supply/exhaust port 22a.
Further, the air exhaust port opening/closing portion 31a of the head valve piston 31 protrudes from the center opening of the head valve piston stopper 32 into the air exhaust port 15 to close between the air exhaust port 15 and the air supply/exhaust port 22a of the striking piston stopper 22. Thereby, the compressed air supplied from the main chamber 13 to the striking cylinder 2 is not exhausted from the air exhaust port 15. Therefore, the striking piston 20 descends, so that a nail (not shown) is struck out by the striking driver 21.
Then, when the trigger lever 4 is pulled, the switch valve stem 61 is moved to the actuation position, so that the compressed air is supplied from the main chamber 13 into the chamber 70 of the timer chamber 7 and thus the pressure in the chamber 70 starts to rise. However, the piston 81 of the control valve 8 is kept in the standby position until the pressure in the chamber 70 reaches a pressure to actuate the control valve 8. Thereby, the state where the control valve stem 84 is in the standby position and the head valve upper chamber 34 communicates with the passage 50 of the trigger valve 5 via the passage 86 is maintained.
A predetermined time is consumed after the trigger lever 4 is pulled and the pressure in the chamber 70 of the timer chamber 7 starts to rise until the pressure in the chamber 70 reaches a pressure to actuate the control valve 8 and the piston 81 of the control valve 8 is moved to the actuation position.
Therefore, when the contact arm 40 is operated within the predetermined time after the trigger lever 4 is pulled until the pressure in the chamber 70 reaches a pressure to actuate the control valve 8 and the piston 81 of the control valve 8 is moved to the actuation position, the head valve 3 is actuated and the striking piston 20 descends, so that a nail (not shown) is struck out by the striking driver 21, as described above.
As shown in FIG. 6D, when the striking piston 20 descends to a position passing through the small holes 14a, some of the compressed air supplied from the main chamber 13 to the striking cylinder 2 passes through the small holes 14a and flows into the return air chamber 14. Some of the compressed air flowing into the return air chamber 14 is supplied to the cylinder 71a of the reset valve 71.
Thereby, the piston 71b is pushed and the reset valve 71 is moved from the standby position to the actuation position shown in FIG. 4B. When the reset valve 71 is moved to the actuation position, the timer chamber 7 opens the passage 70d, so that the chamber 70 communicates with the atmosphere via the passage 70d and the air exhaust port 70c.
Therefore, while the trigger lever 4 is pulled, the pressure in the chamber 70 of the timer chamber 7 rising over time becomes the atmospheric pressure. Then, when the pressure in the return air chamber 14 drops, the reset valve 71 is moved from the actuation position to the standby position described in FIG. 4A, and when the trigger lever 4 is still pulled, the pressure in the chamber 70 of the timer chamber 7 starts to rise.
Therefore, when the contact arm 40 is operated within the predetermined time after the trigger lever 4 is pulled until the pressure in the chamber 70 reaches the pressure to actuate the control valve 8, the head valve 3 is actuated. In addition, the inside of the chamber 70 of the timer chamber 7 becomes the atmospheric pressure and the control valve 8 is not actuated. Therefore, when the contact arm 40 is operated within the predetermined time after the trigger lever 4 is pulled, a continuous nailing operation is possible. In addition, after the trigger lever 4 is pulled and thus the pressure in the chamber 70 of the timer chamber 7 starts to rise, when the nailing operation is executed, the pressure in the chamber 70 becomes the atmospheric pressure, so that a time measurement value using the timer chamber 7 is cleared.
FIGS. 7A and 7B are sectional views showing an example of the operation of the nailing machine where the control valve is actuated. While the trigger lever 4 is pulled, the pressure in the chamber 70 of the timer chamber 7 rises over time. As shown in FIG. 7A, when the pressure in the chamber 70 reaches the pressure to actuate the control valve 8, the piston 81 of the control valve 8 is moved from the standby position to the actuation position described in FIG. 5B and the control valve stem 84 is pushed and moved to the actuation position by the piston 81. When the control valve stem 84 is moved to the actuation position in the control valve 8, the passage 86 is closed, so that the head valve upper chamber 34 does not communicate with the passage 50 of the trigger valve 5 via the passage 86. On the other hand, the passage 87 is opened, so that the head valve upper chamber 34 communicates with the main chamber 13 via the passage 87.
Thereby, as shown in FIG. 7B, even when the trigger valve stem 54 and the pilot valve 52 of the trigger valve 5 are actuated by the operation of the contact arm 40, the head valve upper chamber 34 becomes the same pressure as the main chamber 13 and the head valve pilot valve 31 is not moved from the standby position. In this way, when the contact arm 40 is not operated within the predetermined time after the trigger lever 4 is pulled until the pressure in the chamber 70 reaches the pressure to actuate the control valve 8, the head valve 3 is not actuated even though the contact arm 40 is operated after the predetermined time elapses.
In the time measurement mechanism using the above-described timer chamber 7, the time until the pressure in the chamber 70 reaches the pressure to actuate the control valve 8 depends on a magnitude of the pressure in the main chamber 13. In addition, the time until the piston 81 of the control valve 8 is moved from the standby position to the actuation position depends on an actuation amount of the piston 81 and a load of the spring 82, which is a load against the actuation of the piston 81, in addition to the magnitude of the pressure in the main chamber 13. Therefore, the time after the trigger lever 4 is pulled and becomes in the ON state and the pressure in the chamber 70 starts to rise until the control valve stem 84 of the control valve 8 is moved to the actuation position and the head valve 3 is put into the non-actuation depends on the pressure in the main chamber 13, the actuation amount of the piston 81 and the load.
Therefore, in a nailing machine 1A of a first embodiment to be described later, it is controlled that a flow rate of the compressed air that is supplied to the timer chamber 7 is caused to change according to the pressure in the main chamber 13 and the time until the pressure in the chamber 70 reaches the pressure to actuate the control valve 8 is constant irrespective of the magnitude of the pressure in the main chamber 13.
In a nailing machine 1B of a second embodiment, it is controlled that a volume of the chamber 70 of a timer chamber 7B is caused to change according to the pressure in the main chamber 13 and the time until the pressure in the chamber 70 reaches the pressure to actuate the control valve 8 is constant irrespective of the magnitude of the pressure in the main chamber 13.
In a nailing machine 1C of a third embodiment, it is controlled that a stroke of reciprocal movement of the piston 81C of a control valve 8C is caused to change according to the pressure in the main chamber 13 and the time until the control valve 8C is moved to the actuation position is constant irrespective of the magnitude of the pressure in the main chamber 13.
In a nailing machine 1D of a fourth embodiment, it is controlled that a force of a spring 82D for urging a piston 81D of a control valve 8D is caused to change according to the pressure in the main chamber 13 and the time until the control valve 8D is moved to the actuation position is constant irrespective of the magnitude of the pressure in the main chamber 13.
In addition, a load at the time when the piston 81 and the control valve stem 84 of the control valve 8 are moved also changes depending on a temperature. For example, when the hardness of the O-ring changes depending on temperature levels, a sliding resistance changes.
Therefore, in a nailing machine IE of a fifth embodiment, it is controlled that a flow rate of the compressed air that is suppressed to the timer chamber 7 is caused to change according to the temperature and the time until the control valve 8 is moved to the actuation position is constant irrespective of the temperature.

FIGS. 8A and 8B are sectional views showing an example of a nailing machine of a first embodiment. Note that, in a nailing machine 1A of the first embodiment, the configurations equivalent to those of the nailing machine 1 described in FIG. 1 and the like are denoted with the same reference signs, and the detailed descriptions thereof are omitted.
The nailing machine 1A includes a flow rate control valve 9A configured to control a flow rate of the compressed air that is supplied to the timer chamber 7 via a switch valve 6A. The flow rate control valve 9A is an example of the flow rate control mechanism, is provided in the main chamber 13 within the grip part 12, and has a cylinder 90, a flow rate control valve stem 91 configured to reciprocally move in the cylinder 90, and a spring 92 for urging the flow rate control valve stem 91.
The flow rate control valve 9A has a first throttle 90a and a second throttle 90b configured to communicate with the passage 63 of the switch valve 6A, and a passage 90c configured to communicate with the main chamber 13. In addition, the flow rate control valve stem 91 has an O-ring 91a configured to open/close the second throttle 90b.
In the flow rate control valve 9A, the compressed air in the main chamber 13 is supplied into the cylinder 90 via the passage 90c and the flow rate control valve stem 91 is actuated according to the pressure in the main chamber 13. When the pressure in the main chamber 13 is a first pressure, the flow rate control valve stem 91 is moved to a first position shown in FIG. 8A by the spring 92. On the other hand, when the pressure in the main chamber 13 is a second pressure higher than the first pressure, the flow rate control valve stem 91 is moved to a second position shown in FIG. 8B.
In a state where the flow rate control valve stem 91 is moved to the first position, the first throttle 90a is opened, and the second throttle 90b is opened by the O-ring 91a. Thereby, the passage 63 of the switch valve 6A communicates with the main chamber 13 via the first throttle 90a and the second throttle 90b.
In a state where the flow rate control valve stem 91 is moved to the second position, the first throttle 90a is opened, and the second throttle 90b is closed by the O-ring 91a. Thereby, the passage 63 of the switch valve 6A communicates with the main chamber 13 via the first throttle 90a.
In the switch valve 6A, when the switch valve stem 61 is moved to the actuation position shown in FIG. 3B and the like, the passage 63 is opened. Thereby, in the state where the flow rate control valve stem 91 is moved to the first position, the main chamber 13 communicates with the timer chamber 7 via the first throttle 90a, the second throttle 90b and the passage 63. In addition, in the state where the flow rate control valve stem 91 is moved to the second position, the main chamber 13 communicates with the timer chamber 7 via the first throttle 90a and the passage 63.
Therefore, when the pressure in the main chamber 13 is the second pressure higher than the first pressure, a flow rate of the compressed air that is supplied to the chamber 70 of the timer chamber 7 is reduced, as compared to the case where the pressure in the main chamber 13 is the first pressure. Therefore, it can be controlled that the flow rate of the compressed air that is supplied to the timer chamber 7 changes according to the pressure in the main chamber 13 and the time until the pressure in the chamber 70 reaches the pressure to actuate the control valve 8 is constant irrespective of the magnitude of the pressure in the main chamber 13. Thereby, when performing the contact striking, the time in which the continuous driving operation can be performed can be made constant.

FIGS. 9A and 9B are sectional views showing an example of a nailing machine of a second embodiment. Note that, in a nailing machine 1B of the second embodiment, the configurations equivalent to those of the nailing machine 1 described in FIG. 1 and the like are denoted with the same reference signs, and the detailed descriptions thereof are omitted.
The nailing machine 1B has a sub-chamber 73 and a sub-chamber opening/closing valve 74, which are provided to a timer chamber 7B, as an adjustment mechanism. The sub-chamber opening/closing valve 74 has a cylinder 75, a sub-chamber opening/closing valve stem 76 configured to reciprocally move in the cylinder 75, and a spring 77 for urging the sub-chamber opening/closing valve stem 76.
The timer chamber 7B has a passage 73a configured to communicate the chamber 70 and the sub-chamber 73. The cylinder 75 also has a passage 75a configured to communicate with the main chamber 13. The sub-chamber opening/closing valve 76 also has an O-ring 76a configured to open/close the passage 73a.
In the timer chamber 7B, the compressed air in the main chamber 13 is supplied into the cylinder 75 via the passage 75a and the sub-chamber opening/closing valve stem 76 is actuated according to the pressure in the main chamber 13. When the pressure in the main chamber 13 is a first pressure, the sub-chamber opening/closing valve stem 76 is moved to a first position shown in FIG. 9A by the spring 77. On the other hand, when the pressure in the main chamber 13 is a second pressure higher than the first pressure, the sub-chamber opening/closing valve stem 76 is moved to a second position shown in FIG. 9B.
In a state where the sub-chamber opening/closing valve stem 76 is moved to the first position, the passage 73a is closed by the O-ring 76a. Thereby, the chamber 70 and the sub-chamber 73 do not communicate. In a state where the sub-chamber opening/closing valve stem 76 is moved to the second position, the passage 73a is opened by the O-ring 76a. Thereby, the chamber 70 and the sub-chamber 73 communicate.
In the switch valve 6, when the switch valve stem 61 is moved to the actuation position shown in FIG. 3B and the like, the passage 63 is opened, so that the main chamber 13 communicates with the chamber 70 of the timer chamber 7B via the passage 63.
In a state where the sub-chamber opening/closing valve stem 76 is moved to the first position, the compressed air is caused to flow from the main chamber 13 into only the chamber 70, so that the pressure in the chamber 70 starts to rise. In a state where the sub-chamber opening/closing valve stem 76 is moved to the second position, the compressed air is caused to flow from the main chamber 13 into the chamber 70 and the sub-chamber 73 via the chamber 70, so that the pressure in the chamber 70 and the sub-chamber start to rise.
Therefore, when the pressure in the main chamber 13 is the second pressure higher than the first pressure, a volume of the timer chamber 7B becomes a sum of the chamber 70 and the sub-chamber 73 and the pressure in the main chamber 13 is increased, as compared to the case where the pressure in the main chamber 13 is the first pressure. Therefore, it can be controlled that the volume of the timer chamber 7B changes according to the pressure in the main chamber 13 and the time until the pressure in the chamber 7B reaches the pressure to actuate the control valve 8 is constant irrespective of the magnitude of the pressure in the main chamber 13. Thereby, when performing the contact striking, the time in which the continuous driving operation can be performed can be made constant.

FIGS. 10A and 10B are sectional views showing an example of a nailing machine of a third embodiment. Note that, in a nailing machine 1C of the third embodiment, the configurations equivalent to those of the nailing machine 1 described in FIG. 1 and the like are denoted with the same reference signs, and the detailed descriptions thereof are omitted.
The nailing machine 1C includes a cylinder 88C, a sub-piston 89C connected to the piston 81 and configured to reciprocally move in the cylinder 88C, and a spring 89Ca for urging the sub-piston 89C toward the piston 81, which are provided to a control valve 8C, as the adjustment mechanism. The sub-piston 89C is an example of the sub-actuation member, is provided coaxially with the piston 81, and is configured to control the standby position of the piston 81.
The cylinder 88C has a passage 88Ca configured to communicate with the main chamber 13. The cylinder 88C is provided with the passage 88Ca in a position in which the compressed air entering from the passage 88Ca presses the sub-piston 89C in a direction away from the control valve stem 84.
In the control valve 8C, the compressed air in the main chamber 13 is supplied into the cylinder 88C via the passage 88Ca and the sub-piston 89C is actuated according to the pressure in the main chamber 13. When the pressure in the main chamber 13 is a first pressure, the sub-piston 89C is moved to a first position shown in FIG. 10A by the spring 89Ca. On the other hand, when the pressure in the main chamber 13 is a second pressure higher than the first pressure, the sub-piston 89C is moved to a second position shown in FIG. 10B.
In a state where the sub-piston 89C is moved to the first position, the standby position of the piston 81 comes close to the control valve stem 84. Thereby, a stroke of the piston 81 for moving the control valve stem 84 moved to the standby position to the actuation position is shortened. In a state where the sub-piston 89C is moved to the second position, the standby position of the piston 81 is away from the control valve stem 84. Thereby, the stroke of the piston 81 for moving the control valve stem 84 moved to the standby position to the actuation position is lengthened.
Therefore, when the pressure in the main chamber 13 is the second pressure higher than the first pressure, the stroke of the piston 81 is lengthened. Therefore, it can be controlled that the stroke of the piston 81 changes according to the pressure in the main chamber 13 and the time until the control valve stem 84 reaches the actuation position is constant irrespective of the magnitude of the pressure in the main chamber 13. Thereby, when performing the contact striking, the time in which the continuous driving operation can be performed can be made constant.

FIGS. 11A and 11B are sectional views showing an example of a nailing machine of a fourth embodiment. Note that, in a nailing machine 1D of the fourth embodiment, the configurations equivalent to those of the nailing machine 1 described in FIG. 1 and the like are denoted with the same reference signs, and the detailed descriptions thereof are omitted.
The nailing machine 1D has a cylinder 88D and a spring load control piston 89D configured to reciprocally move in the cylinder 88D, which are provided to a control valve 8D, as the adjustment mechanism. The spring load control piston 89D is an example of the load control member, is provided coaxially with the piston 81, and is configured to control a length in an expansion and contraction direction of the spring 82 for urging the piston 81.
The cylinder 88D has a passage 88Da configured to communicate with the main chamber 13. The cylinder 88D is provided with the passage 88Da in a position in which the compressed air entering from the passage 88Da presses the spring load control piston 89D in a direction of compressing the spring 82.
In the control valve 8D, the compressed air in the main chamber 13 is supplied into the cylinder 88D via the passage 88Da and the spring load control piston 89D is actuated according to the pressure in the main chamber 13. When the pressure in the main chamber 13 is a first pressure, the spring load control piston 89D is moved to a first position shown in FIG. 11A by the spring 82. On the other hand, when the pressure in the main chamber 13 is a second pressure higher than the first pressure, the spring load control piston 89D is moved to a second position shown in FIG. 11B.
In a state where the spring load control piston 89D is moved to the first position, the spring load control piston 89D separates from the piston 81. Thereby, a load of the spring 82 that is applied to the piston 81 located in the standby position is weakened. In a state where the spring load control piston 89D is moved to the second position, the spring load control piston 89D comes close to the piston 81. Thereby, the load of the spring 82 that is applied to the piston 81 located in the standby position is strengthened.
Therefore, when the pressure in the main chamber 13 is the second pressure higher than the first pressure, the load of the spring 82 that is applied to the piston 81 located in the standby position is strengthened. Therefore, it can be controlled that the load of the spring 82 that is applied to the piston 81 located in the standby position changes according to the pressure in the main chamber 13 and the time until the control valve stem 84 reaches the actuation position is constant irrespective of the magnitude of the pressure in the main chamber 13. Thereby, when performing the contact striking, the time in which the continuous driving operation can be performed can be made constant.

FIGS. 12A and 12B are sectional views showing an example of a nailing machine of a fifth embodiment. Note that, in a nailing machine IE of the fifth embodiment, the configurations equivalent to those of the nailing machine 1 described in FIG. 1 and the like are denoted with the same reference signs, and the detailed descriptions thereof are omitted.
The nailing machine IE includes a flow rate control member 93 configured to control a flow rate of the compressed air that is supplied to the timer chamber 7 via a switch valve 6E. The flow rate control member 93 is an example of the adjustment mechanism, and is made of a material having a thermal expansion coefficient different from that of a material of the passage 63b configured to communicate with the passage 63 of the switch valve 6E. The passage 63b is made of metal (aluminum). Note that, the passage 63b may also be made of the same material as the main body 10 and the grip part 12. In addition, the flow rate control member 93 is made of resin.
The flow rate control member 93 is attached in the passage 63b, and a gap S5 through which air passes is formed between an outer periphery of the flow rate control member 93 and an inner periphery of the passage 63b. The flow rate control member 93 is configured to function as a throttle configured to regulate a flow rate in the passage 63b. In addition, since ratios of expansion and contraction of the passage 63b and the flow rate control member 93 due to change in temperature are different, a dimension of the gap S5 between the outer periphery of the flow rate control member 93 and the inner periphery of the passage 63b changes depending on the temperature.
Therefore, at temperatures at which the sliding resistances of the piston 81 and the control valve stem 84 of the control valve 8 increase, the dimension of the gap S5 between the outer periphery of the flow rate control member 93 and the inner periphery of the passage 63b is increased so that the flow rate of the compressed air to be supplied to the chamber 70 of the timer chamber 7 increases. In addition, at temperatures at which the sliding resistances of the piston 81 and the control valve stem 84 of the control valve 8 decrease, the dimension of the gap S5 between the outer periphery of the flow rate control member 93 and the inner periphery of the passage 63b is reduced so that the flow rate of the compressed air to be supplied to the chamber 70 of the timer chamber 7 decreases. In the present example, the passage 63b and the flow rate control member 93 are constituted by a combination of materials that increases the gap S5 between the passage 63b and the flow rate control member 93 as the temperature drops.
Therefore, it can be controlled that the flow rate of the compressed air that is supplied to the timer chamber 7 changes according to the temperature and the time until the control valve stem 84 reaches the actuation position is constant irrespective of the temperature levels. Thereby, when performing the contact striking, the time in which the continuous driving operation can be performed can be made constant.
Note that, in each of the above-described embodiments, the configuration where the control valve 8 is arranged between the head valve 3 and the trigger valve 5 has been described. However, the control valve 8 may also be provided at another place to control discharge of the compressed air supplied to the head valve upper chamber 34. For example, a configuration is possible in which the control valve is provided on a downstream side other than the upstream side of the trigger valve, the trigger valve is arranged between the head valve and the control valve, a passage configured to pass through the trigger valve from the head valve upper chamber and to communicate with the control valve is formed and the opening and closing of the passage configured to discharge the compressed air in the head valve upper chamber to the atmosphere is switched by the control valve.
In the pneumatic tool of the present disclosure, the actuation timing, the actuation amount and the like of the control valve are switched according to the variation factors such as an air pressure, a temperature and the like of the compressed air that is supplied to the chamber, and the timing to switch the actuation and non-actuation of the to-be-controlled object is controlled according to the variation factors.
In the pneumatic tool of the present disclosure, the timing to switch the actuation and non-actuation of the to-be-controlled object can be made constant, irrespective of the variation factors such as air pressure levels of the compressed air and temperature levels.
The present application is based on Japanese Patent Application No.2019-086668 filed on April 26, 2019 , the contents of which are incorporated herein by reference.

REFERENCE SIGNS LIST

1, 1A, 1B, 1C, 1D, 1E: nailing machine (pneumatic tool), 10: main body, 11: nose, 11a: ejection hole, 12: grip part, 13: main chamber, 14: return air chamber, 14a: small hole, 14b: check valve, 15: air exhaust port, 2: striking cylinder, 20: striking piston, 20a: O-ring, 21: striking driver, 22: striking piston stopper, 22a: air supply/exhaust port, 22b: concave portion, 3: head valve (to-be-controlled object), 30: head valve cylinder, 31: head valve piston, 31a: air exhaust port opening/closing portion, 32: head valve piston stopper, 33: spring, 34: head valve upper chamber, 35: head valve seal, 4: trigger lever, 40: contact arm, 40a: pressing member, 40b: compression spring, 41: shaft, 42: large lever, 43: shaft, 44: small lever, 5: trigger valve, 50: passage, 51: housing, 52: pilot valve, 52a, 52b, 52c: O-ring, 52d: passage, 53: cap, 53a: empty chamber, 54: trigger valve stem, 54a, 54b: O-ring, 55: spring, 56: passage, S1, S2, S3: gap, 6: switch valve, 60: cylinder, 61: switch valve stem, 61a:, 61b: O-ring, 62: spring, 63, 63b, 64: passage, 63a: throttle, 64a: passage, 65: passage, 7: timer chamber, 70: chamber, 70a: inlet, 70b: outlet, 70c: air exhaust port, 70d: passage, 71: reset valve, 71a: cylinder, 71b: piston, 71c: O-ring, 72: spring, 73: sub-chamber (adjustment mechanism), 73a: passage, 74: sub-chamber opening/closing valve (adjustment mechanism), 75: cylinder, 75a: passage, 76: sub-chamber opening/closing valve stem, 76a: O-ring, 77: spring, 8: control valve, 80: cylinder, 81: piston (actuation member), 82: spring, 83: cylinder, 84: control valve stem, 84a, 84b: O-ring, 85: spring, 86, 87: passage, 88C: cylinder, 88Ca: passage, 89C: sub-piston (sub-actuation member), 89Ca: spring, 88D: cylinder, 88Da: passage, 89D: spring load control piston (load control member), 9A: flow rate control valve (flow rate control mechanism), 90: cylinder, 90a: first throttle, 90b: second throttle, 90c: passage, 91: flow rate control valve stem, 91a: O-ring, 92: spring, 93: flow rate control member (adjustment mechanism)

Claims

A pneumatic tool comprising:
a chamber having a predetermined volume to which compressed air is supplied;

a control valve connected to the chamber and configured to switch actuation and non-actuation of a to-be-controlled object; and

an adjustment mechanism configured to switch actuation of the control valve.
The pneumatic tool according to Claim 1, wherein the control valve comprises an actuation member configured to be actuated by an air pressure in the chamber, and
wherein the adjustment mechanism is configured to switch actuation of the actuation member, according to an air pressure of the compressed air that is supplied to the chamber.
The pneumatic tool according to Claim 1 or 2, wherein the adjustment mechanism comprises a flow rate control mechanism configured to control a flow rate of the compressed air that is supplied to the chamber, according to an air pressure of the compressed air that is supplied to the chamber.
The pneumatic tool according to Claim 1 or 2, wherein the adjustment mechanism is configured to increase or decrease the volume of the chamber, according to an air pressure of the compressed air that is supplied to the chamber.
The pneumatic tool according to Claim 4, wherein the adjustment mechanism comprises:
a sub-chamber connected to the chamber,

a passage configured to communicate the chamber and the sub-chamber therebetween, and

a sub-chamber opening/closing valve configured to open/close the passage, according to the air pressure of the compressed air that is supplied to the chamber.
The pneumatic tool according to Claim 2, wherein the adjustment mechanism comprises a sub-actuation member configured to control an actuation amount of the actuation member of the control valve, according to an air pressure of the compressed air that is supplied to the chamber.
The pneumatic tool according to Claim 2, wherein the adjustment mechanism comprises a load control member configured to control a load of the actuation member of the control valve, according to an air pressure of the compressed air that is supplied to the chamber.
The pneumatic tool according to Claim 1, wherein the adjustment mechanism is configured to switch the actuation of the control valve, according to a temperature.
The pneumatic tool according to Claim 8, wherein the adjustment mechanism comprises:
a passage through which the compressed air passes,

a flow rate control member made of a material having a thermal expansion coefficient different from that of the passage.
The pneumatic tool according to Claim 9, wherein the passage and the flow rate control member are constituted by a combination of materials that increases a gap between the passage and the flow rate control member as the temperature drops.
The pneumatic tool according to Claim 9 or 10, wherein the passage and the flow rate control member constitute a throttle configured to regulate a flow rate of the compressed air that passes through the passage.
The pneumatic tool according to any one of Claims 1 to 11, further comprising:
a striking piston to which a striking driver configured to strike out a nail supplied in a nose is connected,

a striking cylinder in which the striking piston is configured to reciprocally move,

a head valve configured to communicate and shut off between an inside of a main chamber to which the compressed air is supplied and the striking cylinder,

a trigger lever configured to receive an operation for actuating the head valve,

a contact arm configured to be able to reciprocally move in an axial direction of the nose,

a trigger valve configured to actuate the head valve by operations of the trigger lever and the contact arm, and

a switch valve configured to supply the compressed air from the main chamber to the chamber by the operation of the trigger lever,

wherein the control valve is configured to switch opening/closing of a passage configured to communicate the trigger valve and the head valve.
The pneumatic tool according to any one of Claims 1 to 11, further comprising:
a striking piston to which a striking driver configured to strike out a nail supplied in a nose is connected,

a striking cylinder in which the striking piston is configured to reciprocally move,

a head valve configured to communicate and shut off between an inside of a main chamber to which the compressed air is supplied and the striking cylinder,

a trigger lever configured to receive an operation for actuating the head valve,

a contact arm configured to be able to reciprocally move in an axial direction of the nose,

a trigger valve configured to actuate the head valve by operations of the trigger lever and the contact arm, and

a switch valve configured to supply the compressed air from the main chamber to the chamber by the operation of the trigger lever,

wherein the control valve is configured to switch opening/closing of a passage for discharging, to an atmosphere, the compressed air in a head valve upper chamber in which the compressed air for actuating the head valve is reserved.