JP7226072B2 - pneumatic tools - Google Patents

Description

The present disclosure relates to pneumatic tools.

Conventionally, a nail includes a main body having a cylinder, a piston slidably provided inside the cylinder, and a driver connected to the piston, and drives the nail into a member to be nailed by driving the piston with compressed air. Hammers are widely used.

A nail gun that uses compressed air has a head valve that controls the operation of the piston, a trigger valve that operates the head valve, a trigger mechanism that operates the trigger valve, and a nose portion that protrudes from the tip of the main body. and a contact arm. In a nailing machine, for example, when a contact arm is pressed against a member to be nailed while a trigger lever is pulled, a nailing operation (hereinafter referred to as contact driving) is performed in which a driver drives a nail into the member to be nailed. It is possible.

In contact driving, after driving the nail, the nail can be driven continuously each time the contact arm is pressed against the workpiece while the trigger is still pulled, so it is suitable for quick work. On the other hand, in order to restrict inadvertent operation, a technique has been proposed in which the head valve is deactivated when a predetermined time elapses without the contact arm being pressed against the workpiece after the trigger is pulled. (See Patent Document 1, for example).

Japanese Utility Model Publication No. 6-32308

However, the conventional nailing machine disclosed in Patent Document 1 and the like has the following problems. The timing valve utilizes compressed air from the main chamber or the like. Therefore, oil, drain, fine dust, and the like contained in the compressed air supplied to the nailing machine may adhere to the flow path (restricted portion) and the like, causing the flow rate of the compressed air to fluctuate. As a result, the timing of the timer mechanism fluctuates, and the operation of the timer mechanism is unstable.

Therefore, in order to solve the above problems, the present disclosure eliminates the effects of oil, drain, fine dust, etc. contained in the compressed air supplied to the nailing machine, and stabilizes the operation of the timer mechanism. To provide a pneumatic tool capable of

A pneumatic tool according to an aspect of the present disclosure includes a drive mechanism driven by the air pressure of compressed air, a chamber supplied with compressed air for driving the drive mechanism, and the compressed air supplied to the chamber. a head valve that drives the drive mechanism; a trigger valve that operates the head valve; a control valve that operates in accordance with the operation of the trigger valve and disables the operation of the head valve; and a timer valve that disables the operation of the head valve by operating the control valve at a predetermined timing. Further, the chamber and the accommodating portion are configured as spaces that are isolated from each other.

Further, a pneumatic tool according to an aspect of the present disclosure includes a drive mechanism driven by air pressure of compressed air, a first chamber supplied with compressed air for driving the drive mechanism, and a a head valve that drives the drive mechanism using the compressed air; a trigger valve that operates the head valve; a control valve that operates in accordance with the operation of the trigger valve and disables the operation of the head valve; a timer valve that operates based on the operation of a trigger and disables the operation of the head valve by operating the control valve at a predetermined timing, the timer valve for operating the control valve. It has a narrowed portion for regulating the flow of compressed air, and the compressed air is caused to flow through the narrowed portion at a predetermined timing interlocked with the driving operation by the drive mechanism.

According to the present invention, since the timer valve is operated using the air in the housing portion that is isolated from the chamber without using the compressed air used to drive the drive mechanism, dust, oil, etc. will not enter the timer valve. intrusion can be prevented.

Further, according to the present invention, since compressed air is flowed through the narrowed portion in conjunction with the driving operation, impurities such as dust and oil adhering to the narrowed portion can be removed by the compressed air. As a result, it is possible to stabilize the time until the control valve of the timer valve is actuated.

1 is a side cross-sectional view of a nailing machine according to a first embodiment; FIG. 1 is a side cross-sectional view of a control valve, a trigger valve, and a switch valve according to the first embodiment; FIG. It is a side cross-sectional view of a timer valve according to the first embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 1st embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 1st embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 1st embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 1st embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 1st embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 1st embodiment. It is a figure at the time of driving operation in the nailing machine according to the first embodiment. It is a side cross-sectional view of a nail driver according to a second embodiment. It is a side cross-sectional view of a timer valve according to a second embodiment. It is a side cross-sectional view of a control valve according to a second embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 2nd embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 2nd embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 2nd embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 2nd embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 2nd embodiment. It is a figure at the time of driving operation in the nailing machine concerning a 2nd embodiment.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<First embodiment>
[Configuration example of nailing machine 100]
FIG. 1 is a side sectional view of a nailing machine 100 according to the first embodiment. FIG. 2 is a side sectional view of the trigger valve 50, switch valve 70 and control valve 40 according to the first embodiment. FIG. 3 is a side sectional view of the timer valve 80 according to the first embodiment.

A nailing machine 100 is an example of a pneumatic tool, and as shown in FIG. 6. The casings of the main body 1 and the grip portion 4 are integrally formed by, for example, a housing 1a. The nailing machine 100 also includes a head valve 30 , a trigger mechanism 10 , a trigger valve 50 , a switch valve 70 , a timer valve 80 and a control valve 40 .

In this embodiment, the nose portion 2 side of the nailing machine 100 is the bottom side of the nailing machine 100, and the opposite side is the top side of the nailing machine 100. As shown in FIG. Further, the main body 1 side of the nailer 100 is the front side of the nailer 100, and the grip portion 4 side of the nailer 100 is the rear side of the nailer 100.

The interior of the main body 1 is hollow, and a striking mechanism (driving mechanism) 20 driven by the air pressure of compressed air is arranged inside the main body 1 . The striking mechanism 20 has a driver 22 , a piston 24 and a cylinder 26 . The driver 22 reciprocates in the vertical direction (axial direction) inside the cylinder 26 and strikes the head of the nail delivered from the magazine section 6 to drive the nail into the nailed member. The piston 24 is connected to the upper end of the driver 22 and reciprocates within the cylinder 26 in response to compressed air flowing into a piston upper chamber 24 a provided on the upper side of the cylinder 26 . The cylinder 26 is a cylindrical body, is arranged inside the housing 1a that constitutes the main body 1, and accommodates the driver 22 and the piston 24 so that they can reciprocate in the vertical direction. An annular locking portion 25 is provided between the piston 24 and the head valve 30 to restrict upward movement of the piston 24 .

A nose portion 2 is provided at the lower end portion of the main body 1 . The nose portion 2 protrudes downward from the lower end portion of the main body 1 by a predetermined length. The nose portion 2 is formed with an ejection port 3 through which the nail sent out by the driver 22 is driven out. The injection port 3 is arranged coaxially with the driver 22 and the cylinder 26 .

A main chamber 5 to which compressed air is supplied and filled is provided between the upper inner wall of the main body 1 and the upper outer peripheral portion of the cylinder 26 and inside the grip portion 4 . A blowback chamber 28 for returning the piston 24 to the top dead center is provided between the inner wall on the lower side of the main body 1 and the outer peripheral portion on the lower side of the cylinder 26 . One end of the first connection path 29 communicating with the switch valve 70 communicates with the blowback chamber 28 .

A plurality of small holes 27 are formed at predetermined intervals in the circumferential direction of the cylinder 26 at a substantially intermediate position in the axial direction of the cylinder 26 . The plurality of small holes 27 communicate with the blowback chamber 28 via check valves 27a provided in the cylinder 26 . When the piston 24 is positioned at the bottom dead center below the small hole 27 , the compressed air from the cylinder 26 flows into the blowback chamber 28 through the small hole 27 . Also, when the piston 24 is positioned at the top dead center, the compressed air inside the blowback chamber 28 is released to the atmosphere, and the inside of the blowback chamber 28 becomes atmospheric pressure.

The head valve 30 supplies and cuts off compressed air to the cylinder 26 and drives the striking mechanism 20 using the compressed air supplied from the main chamber 5 . The head valve 30 has a base portion 32 and a movable portion 34 . The base portion 32 is arranged on the upper end side inside the main body 1 , and the movable portion 34 is arranged on the lower side of the base portion 32 . The movable portion 34 is biased toward the cylinder 26 with a predetermined gap from the base portion 32 by a biasing spring 36 interposed between the base portion 32 and the movable portion 34 . The lower surface of the movable portion 34 is in contact with the upper surface of the locking portion 25 in the energized state (the head valve 30 is in the OFF state), and the structure is such that the main chamber 5 and the piston upper chamber 24a are blocked. .

A gap between the base portion 32 and the movable portion 34 functions as a head valve chamber 38 to which the compressed air inside the main chamber 5 is supplied. One end of the second connection path 39 communicates with the head valve chamber 38 , and the other end of the second connection path 39 communicates with the control valve 40 . The movable part 34 slides along the inner wall of the housing 1a constituting the main body 1 according to the state of the compressed air inside the head valve chamber 38, and opens and closes between the piston upper chamber 24a and the main chamber 5. . The piston upper chamber 24a communicates with the outside through an opening 1b formed in the housing 1a.

The grip portion 4 is attached to a rear side portion of the main body 1 in a direction substantially orthogonal to the extending direction of the main body 1 (the axial direction of the cylinder 26). An air plug 8 is provided at the rear end of the grip portion 4 . One end of an air hose (not shown) is connected to the air plug 8, and the other end of the air hose is connected to a compressor (not shown). The air compressor generates compressed air for driving the striking mechanism 20 and supplies the generated compressed air to the inside of the main chamber 5 via the air hose and the air plug 8 .

The trigger mechanism 10 has a trigger lever 11 , a contact lever 12 , a contact arm 14 and a pressing member 15 . The trigger lever 11 is a lever that turns on (actuates) the switch valve 70, and is attached to the lower side of the grip portion 4 on the rear side of the main body 1 so as to be rotatable about a shaft portion. The contact lever 12 is arranged inside the trigger lever 11 and rotates in conjunction with the trigger lever 11 with the front end side as a fulcrum. The front end portion of the contact lever 12 is biased downward by, for example, a torsion spring provided on the rear end side, and contacts the upper end surface of the pressing member 15 . It should be noted that the contact lever 12 may not be biased by a spring.

The contact arm 14 is attached to the outer peripheral portion of the nose portion 2 while protruding downward from the lower end portion of the nose portion 2 . The contact arm 14 is biased downward by a spring (not shown), and reciprocates vertically relative to the nose portion 2 as it is pressed against the member to be driven. The pressing member 15 is connected to the contact arm 14 and presses up the front end side of the contact lever 12 as the contact arm 14 moves upward. When the trigger lever 11 is pulled, the trigger valve stem 58 of the trigger valve 50 is pushed up, and the trigger valve 50 is activated (turned on).

The magazine part 6 is configured so that a series of connected nails can be loaded therein, and is provided on the lower side of the grip part 4 . The front end side of the magazine section 6 is connected to the nose section 2 , and the rear end side of the magazine section 6 is connected to the grip section 4 via the mounting arm section 7 . The connecting nail loaded in the magazine portion 6 is guided to the ejection port 3 of the nose portion 2 by a feed claw provided slidably with respect to the nose portion 2, and is hit by being impacted by the driver 22 descending. driven into the insertion member.

The trigger valve 50, as shown in FIGS. 1 and 2, operates the head valve 30 based on the pressing state of the contact arm 14 against the member to be driven. The trigger valve 50 is arranged adjacent to the switch valve 70 on the front end side of the grip portion 4 . Trigger valve 50 includes housing 52 , pilot valve 54 , cap 56 and trigger valve stem 58 .

The housing 52 has a passage 53 in a substantially middle portion in the vertical direction. The passage 53 communicates with one end of a third connection passage 49 that connects the control valve 40 (head valve 30 ) and the trigger valve 50 . Further, the passage 53 can communicate with the exhaust passage 59 when the trigger valve 50 is turned on.

The pilot valve 54 is arranged inside the housing 52 with a gap S1 therebetween. O-rings 54a and 54b are attached to the periphery of the pilot valve 54 on the lower side thereof with a predetermined space therebetween in the vertical direction. The O-ring 54a blocks the passage between the passage 53 and the exhaust passage 59 when the trigger valve 50 is not operated, and prevents the compressed air inside the head valve chamber 38 from leaking out of the passage 53 to the outside. Further, the O-ring 54a is pressed against the inner wall of the housing 52, and the upward movement of the pilot valve 54 is restricted. The O-ring 54b isolates a space 55 and an exhaust passage 59, which will be described later.

The cap 56 is attached inside the housing 52 with a space 55 between it and the pilot valve 54 on the upper side. The empty chamber 55 communicates with the main chamber 5 through the gap S2 between the pilot valve 54 and the trigger valve stem 58 and the passage 54c of the pilot valve 54 when the trigger valve 50 is not operated, and functions as a chamber filled with compressed air. do.

The trigger valve stem 58 is arranged inside the pilot valve 54 and the cap 56 and is provided so as to be vertically movable with the cap 56 as a starting point. The upper end side of the trigger valve stem 58 is urged toward the contact lever 12 (downward) by a compression spring 57 . A compression spring 57 is interposed between the pilot valve 54 and the trigger valve stem 58 and expands and contracts according to the pressure of the trigger valve stem 58 . The lower end of the trigger valve stem 58 protrudes from the lower surface of the cap 56 by a predetermined length and can come into contact with the contact lever 12 (see FIG. 1). O-rings 58a and 58b are attached to the periphery of the trigger valve stem 58 at a substantially intermediate position in the vertical direction with a predetermined space therebetween. The O-rings 58a and 58b prevent the compressed air in the empty chamber 55 from leaking out through the gap S3 between the trigger valve stem 58 and the cap 56 when the trigger valve 50 is not operated.

An exhaust passage 59 is provided between the housing 52 and the cap 56 . The exhaust passage 59 communicates with the passage 53 when the chamber 55 is closed by pushing up the trigger valve stem 58 when the trigger valve 50 is actuated, and exhausts the compressed air inside the head valve chamber 38 to the atmosphere.

As shown in FIGS. 1 and 2, the switch valve 70 is arranged adjacent to the rear side of the trigger valve 50 and operates the timer valve 80 based on the operation of the trigger lever 11 . The switch valve 70 has a cylinder 72 and a switch valve stem 74 .

The cylinder 72 is a cylindrical body having a hollow extending in the vertical direction, and accommodates the switch valve stem 74 so as to be slidable in the vertical direction. A first passage 72 a is formed on the upper side of the cylinder 72 . The first passage 72a communicates with the main chamber 5 and allows the compressed air inside the main chamber 5 to flow into the cylinder 72 via the first passage 72a.

One end of the fourth connection path 79 communicates with a substantially intermediate position in the vertical direction of the cylinder 72 , and the other end of the fourth connection path 79 communicates with the timer valve 80 . A fourth connection path 79 connects the switch valve 70 and the timer valve 80 , and can supply or exhaust compressed air to the timer valve 80 via the fourth connection path 79 . One end of the first connection path 29 communicates with the lower side of the fourth connection path 79 of the cylinder 72 , and the other end of the first connection path 29 communicates with the blowback chamber 28 . The first connection path 29 connects between the switch valve 70 and the blowback chamber 28, and can supply compressed air to the switch valve 70 or exhaust compressed air from the switch valve 70 through the first connection path 29. It has become.

The switch valve stem 74 is accommodated inside the cylinder 72 and is biased toward the trigger lever 11 side (lower side) by a compression spring 76 . The compression spring 76 is interposed between the upper end surface of the switch valve stem 74 and the top surface inside the cylinder 72 and expands and contracts according to the pulling operation of the trigger lever 11 . The lower end of the switch valve stem 74 protrudes downward from the lower surface of the cylinder 72 and contacts the contact lever 12 when the trigger lever 11 (see FIG. 1) is pulled.

An O-ring 74 a is attached to the peripheral portion of the switch valve stem 74 at a substantially intermediate position in the vertical direction to ensure close contact with the inner wall of the cylinder 72 . When the trigger lever 11 is not pulled, the switch valve stem 74 closes the path between the fourth connection path 79 and the first connection path 29 by means of an O-ring 74a, and separates the first path 72a and the fourth connection path 79. communicate. On the other hand, the switch valve stem 74 is pushed up by the contact lever 12 against the elastic force of the compression spring 76 when the trigger lever 11 is pulled. , and communicates the fourth connection path 79 and the first connection path 29 .

As shown in FIGS. 1 and 3, the timer valve 80 operates when the contact arm 14 is pressed against the member to be driven after the trigger lever 11 is pulled and the predetermined time has passed. Activating the control valve 40 at this time disables the driving action. That is, the timer valve 80 operates based on the operation of the trigger lever 11, and disables the operation of the head valve 30 by operating the control valve 40 at a predetermined timing.

The timer valve 80 has a cylinder 90 , a first timer piston 84 , a first piston shaft portion 85 , a second timer piston 94 and a second piston shaft portion 95 .

The cylinder 90 is a hollow cylindrical body extending in the front-rear direction, and houses the first timer piston 84 and the second timer piston 94 so as to be slidable in the front-rear direction. The interior of the cylinder 90 is partitioned into a first chamber 81 and a second chamber 91, which are examples of a housing portion, via a partition portion 90a. The first chamber 81 is a closed space (closed circuit), and is isolated from other spaces such as the second chamber 91 and the main chamber 5 . Moreover, the first chamber 81 is also shut off from the outside air. The inside of the first chamber 81 is filled in advance with the atmosphere (air) used when the timer valve 80 is operated. As a result, it is possible to prevent impurities such as dust and oil from flowing into the first chamber 81 from other spaces.

The first timer piston 84 is a cylindrical body having substantially the same diameter as the inner diameter of the cylinder 90 , and is arranged movably along the inner wall of the cylinder 90 in the extending direction of the grip portion 4 . The first timer piston 84 is biased toward the control valve 40 (front side) by a compression spring 89 . The compression spring 89 is interposed between a recess formed on the base end side of the first timer piston 84 and the rear wall inside the first chamber 81, and expands and contracts according to the advance or retreat of the first timer piston 84. .

A recessed portion 84a is formed along the circumference of the peripheral portion of the first timer piston 84 . An O-ring 86 is attached to the recessed portion 84 a to seal the inner wall of the cylinder 90 . Thereby, the first chamber 81 is further partitioned into a first space 81a on the rear side of the O-ring 86 and a second space 81b on the front side of the O-ring 86 . The first space 81 a and the second space 81 b are shielded from each other by an O-ring 86 .

A first passage 82a and a second passage 82b extending in the front-rear direction are vertically arranged in the lower part of the inside of the cylinder 90 . A front end portion of the first passage 82a communicates with the second space 81b, and a rear end portion of the first passage 82a communicates with the first space 81a. A front end portion of the second passage 82b communicates with the second space 81b, and a rear end portion of the second passage 82b communicates with the first space 81a.

A check valve 87 is provided in the middle of the first passage 82a. The check valve 87 has, for example, a ball 87a that opens and closes the first passage 82a, and a spring 87b that biases the ball 87a rearward. When the first timer piston 84 retreats inside the first chamber 81, the atmosphere flowing from the first space 81a into the first passage 82a causes the ball 87a to move forward against the elastic force of the spring 87b. As a result, the first passage 82a is opened, and the air in the first space 81a of the first chamber 81 flows into the second space 81b. When the first timer piston 84 moves forward inside the first chamber 81, the air flowing from the second space 81b into the first passage 82a and the spring 87b act on the ball 87a, and the ball 87a causes the first passage 82a to move. Since it is closed, the atmosphere in the second space 81b of the cylinder 90 does not flow into the first space 81a through the first passage 82a (reverse flow).

A narrowed portion 88 is provided in the middle of the second passage 82b. The narrowed portion 88 is configured by reducing the cross-sectional area (width) of a portion of the second passage 82b. The restrictor 88 restricts the moving speed of the first timer piston 84 by restricting the flow rate per unit time of the atmosphere flowing from the second space 81b into the second passage 82b. As a result, the movement speed of the second piston shaft portion 95 until it presses the control valve stem 44 of the control valve 40 can be controlled. Further, the specified time for the first timer piston 84 to move from the initial position (bottom dead center) inside the first chamber 81 to the operating position (top dead center) for operating the control valve 40 is It is determined by the flow rate of air passing through the portion 88, the spring coefficient of the compression spring 89, and the like. In this embodiment, the specified time is, for example, 3 seconds to 10 seconds, but is not limited to these. Further, in the present embodiment, the time required for the control valve 40 to move from the operating position to the position that blocks the passage between the head valve chamber 38 and the trigger valve 50 is set to a time significantly shorter than the specified time. . Therefore, the passage between the head valve 30 and the trigger valve 50 is blocked by the control valve 40 immediately after the specified time has elapsed.

The first piston shaft portion 85 is a rod-shaped cylindrical body, and the rear end portion of the first piston shaft portion 85 is attached to the front end portion of the first timer piston 84 . The first piston shaft portion 85 is inserted through a through hole 90b formed in the partition portion 90a, and its front end side extends from the inside of the first chamber 81 to the inside of the second chamber 91. As shown in FIG. A front end portion of the first piston shaft portion 85 is attached to a rear end portion of the second timer piston 94 so that the pressing force of the first timer piston 84 can be transmitted to the second timer piston 94 . An O-ring 90c is attached to the partition portion 90a to ensure that the first chamber 81 is sealed.

The second timer piston 94 is a cylindrical body having substantially the same diameter as the inner diameter of the cylinder 90 , and advances or retreats inside the second chamber 91 according to the pressure from the first piston shaft portion 85 . A recessed portion 94a is formed in the peripheral portion of the second timer piston 94 along its circumferential direction. An O-ring 96 is attached to the recessed portion 94a for sealing between the inner wall of the cylinder 90 and the recessed portion 94a. As a result, the second chamber 91 is further partitioned into a first space 91 a on the rear side of the O-ring 96 and a second space 91 b on the front side of the O-ring 96 .

A passage 90e communicating with the outside of the housing 1a is formed in the first space 91a. One end of a fourth connection path 79 that communicates with the switch valve 70 is connected to the second space 91b. can be exhausted.

The second piston shaft portion 95 is a rod-shaped cylindrical body, and the rear end portion of the second piston shaft portion 95 is attached to the front end portion of the second timer piston 94 . The second piston shaft portion 95 can move in the front-rear direction inside a through hole 90 d formed between the second timer piston 94 and the control valve 40 . The front end portion of the second piston shaft portion 95 is provided so as to be retractable inside the cylinder 42 of the control valve 40 , and presses the rear end surface of the control valve stem 44 that constitutes the control valve 40 to operate the control valve 40 . .

In the present embodiment, as shown in FIGS. 1 and 3, in the timer valve 80, the moving direction of the first timer piston 84 and the second timer piston 94 is different from the axial direction of the cylinder 26 (moving direction of the driver 22). They are arranged inside the grip part 4 so as to have different orientations, in this embodiment perpendicular orientations. In addition, the timer valve 80 is configured such that the moving directions of the first timer piston 84 and the second timer piston 94 are parallel to the extending direction of the grip portion 4 , that is, parallel to the extending direction of the grip portion 4 . It is arranged inside the part 4 .

The control valve 40, as shown in FIGS. 1 and 2, disables the operation of the head valve 30 which operates in conjunction with the operation of the trigger valve 50. FIG. Specifically, the control valve 40 disables the operation of the head valve 30 by switching the passage between the head valve chamber 38 and the trigger valve 50 from the communicating state to the blocking state under the control of the timer valve 80 . The control valve 40 is located forwardly adjacent to the timer valve 80 and between the head valve chamber 38 and the trigger valve 50 . Control valve 40 has a cylinder 42 and a control valve stem 44 . A part of the cylinder 42 has a structure in which a part of the housing 1a is shared.

The cylinder 42 is a hollow cylindrical body extending in the front-rear direction, and accommodates the control valve stem 44 so as to be slidable in the front-rear direction. One end of a second connection path 39 communicating with the head valve chamber 38 communicates with the upper surface side of the cylinder 42 . A passage 42c communicating with the main chamber 5 is formed in the lower surface side of the cylinder 42, while communicating with one end of the third connecting passage 49 communicating with the trigger valve 50. As shown in FIG.

The control valve stem 44 is a cylindrical body that extends in the front-rear direction and is arranged inside the cylinder 42 . The control valve stem 44 is biased against the timer valve 80 (rear side) by the compression spring 46 . The compression spring 46 is interposed between the inner front wall of the cylinder 42 and the front end face of the control valve stem 44 and expands and contracts in response to the pressing by the timer valve 80 . O-rings 44a and 44b are attached to the peripheral portion of the control valve stem 44 at a substantially middle position in the front-rear direction with a predetermined space therebetween in the front-rear direction to ensure close contact with the inner wall of the cylinder 42. As shown in FIG.

The control valve stem 44 is positioned on the rear end side inside the cylinder 42 when the timer valve 80 is not pressed, that is, before timeout, and the O-ring 44b closes the path between the second connecting path 39 and the passage 42c. On the one hand, the path between the second connection path 39 and the third connection path 49 is opened. Thereby, the head valve chamber 38 and the trigger valve 50 are connected. On the other hand, when the timer valve 80 is pressed, that is, after a time-out, the control valve stem 44 moves to the front end side inside the cylinder 42 to open the path between the second connecting path 39 and the passage 42c, while the O The ring 44a closes the path between the second connection path 39 and the third connection path 49. FIG. This blocks the connection between the head valve chamber 38 and the trigger valve 50 .

[Example of operation of nailer 100]
Next, an example of the driving operation of the nailing machine 100 according to the first embodiment will be described. 4 to 10 are diagrams showing the driving operation of the nailing machine 100 according to the first embodiment.

Compressed air is supplied to the interior of the main chamber 5 when an air hose is connected to the air plug 8 of the nailing machine 100 shown in FIG. The compressed air supplied to the interior of the main chamber 5 passes through the first passage 72a of the switch valve 70, the interior of the switch valve 70, and the fourth connection passage 79 to the second passage 79 of the timer valve 80, as shown in FIG. It is supplied to the second space 91 b of the chamber 91 .

Along with this, the front surface of the second timer piston 94 is pushed rearward by the compressed air, and the first timer piston 84 and the first piston shaft portion 85 retreat against the elastic force of the compression spring 89 . At this time, the air in the first space 81a is compressed, and the compressed air flows into the first passage 82a. The ball 87a of the check valve 87 opens the first passage 82a by moving forward against the elastic force of the spring 87b due to the inflowing atmosphere. As a result, the air in the first space 81a flows into the second space 81b via the first passage 82a. In addition, since the flow resistance of the constricted portion 88 is high in the second passage 82b, the compressed air hardly passes through the second passage 82b.

As shown in FIG. 5, when compressed air continues to be supplied to the second chamber 91 of the timer valve 80, the compression of the compression spring 89 causes the first timer piston 84 to move to the initial position inside the cylinder 90, specifically the first position. The base end of the 1 timer piston 84 reaches the rear portion of the first chamber 81 . As a result, the timer valve 80 enters the standby state.

As shown in FIG. 6, when the operator pulls the trigger lever 11, the switch valve stem 74 of the switch valve 70 is pushed up by the contact lever 12, and the switch valve 70 is operated. The O-ring 74a (see FIG. 2) is also moved upward by the operation of the switch valve 70, and the first passage 72a of the switch valve 70 and the fourth connection passage 79 are cut off, while the fourth connection passage 79 and the fourth connection passage 79 are blocked. 1 connection path 29 is communicated. Along with this, the compressed air in the second space 91b of the second chamber 91 of the timer valve 80 passes through the fourth connection path 79, the inside of the switch valve 70, and the first connection path 29 to the atmospheric pressure blowback chamber. 28 is exhausted.

Also, when the compressed air in the second space 91 b of the cylinder 90 is exhausted, the first timer piston 84 advances inside the first chamber 81 by the biasing force of the compression spring 89 . Along with this, the air in the second space 81b of the first chamber 81 passes through the second passage 82b and the narrowed portion 88 and flows into the first space 81a. The flow rate of the air supplied to the first space 81a is restricted to a constant amount by the restrictor 88. As shown in FIG. The compression spring 89 expands according to the flow rate of air flowing into the first space 81a. As a result, the first timer piston 84 slowly moves forward from the initial position inside the first chamber 81, and the timer valve 80 starts timing. Since the first passage 82a is closed by the ball 87a, the air does not flow into the first space 81a through the first passage 82a (reverse flow).

As shown in FIG. 7, when the contact arm 14 is pressed against the driven member while the trigger lever 11 is pulled and before the specified time of the timer valve 80 elapses, the pressing member 15 is pushed up. As a result, the front end side of the contact lever 12 is pushed up, and the trigger valve stem 58 of the trigger valve 50 is pushed up, thereby actuating the trigger valve 50 . When the trigger valve 50 is actuated, the O-rings 58a and 58b also move upward as shown in FIG. be. The pilot valve 54 is pushed down by the compressed air inside the main chamber 5 against the elastic force of the compression spring 57 , and the lower surface of the pilot valve 54 contacts the upper surface of the cap 56 . As a result, the passage 53 and the exhaust passage 59 communicate with each other, and the compressed air inside the head valve chamber 38 flows through the second connection passage 39, the inside of the control valve 40, the third connection passage 49, the inside of the trigger valve 50 and the exhaust passage. It is exhausted to the atmosphere (outside) via 59 .

When the compressed air inside the head valve chamber 38 is exhausted, the movable portion 34 of the head valve 30 is pushed up by the compressed air inside the main chamber 5, opening the gap between the movable portion 34 and the locking portion 25. , the compressed air in the main chamber 5 flows into the piston upper chamber 24a, and the piston 24 rapidly descends inside the cylinder 26. As shown in FIG.

As shown in FIG. 8, when the piston 24 is further lowered, the driver 22 connected to the piston 24 drives the nail into the driven member. Also, when the piston 24 descends to the lower side inside the cylinder 26 , the compressed air inside the cylinder 26 flows into the blowback chamber 28 through the small hole 27 . The inflowing compressed air flows into the second chamber 91 of the timer valve 80 via the first connection path 29 , the inside of the switch valve 70 and the fourth connection path 79 . As a result, the timer valve 80 is again retracted to the initial position inside the first chamber 81, and the timer valve 80 is reset. As the timer valve 80 retreats, the atmosphere in the first space 81a flows into the second space 81b via the second passage 82b and the check valve 87, as described with reference to FIG.

On the other hand, as shown in FIG. 9, the contact arm 14 is not pressed against the member to be driven within a preset specified time after the operator pulls the trigger lever 11 shown in FIG. If so, ie no firing action is performed, the timer valve 80 times out. Specifically, the second piston shaft portion 95 of the timer valve 80 moves to the operating position where it presses the control valve 40 when the specified time elapses.

The control valve stem 44 of the control valve 40 is pushed forward by the second piston shaft portion 95 and moves to the front end side of the cylinder 42 . When the control valve stem 44 moves forward, the O-rings 44a and 44b also move forward, blocking the path connecting the second connection path 39 and the third connection path 49, while forming a gap S4. As a result, the head valve chamber 38 switches from communicating with the trigger valve 50 to communicating with the main chamber 5 via the second connection path 39 , the gap S<b>4 and the passage 42 a of the control valve 40 .

As shown in FIG. 10, when the operator shown in FIG. 6 pulls the trigger lever 11 and after the timer valve 80 times out, the contact arm 14 is pressed against the member to be driven. , the pressing member 15 is pushed up. Accordingly, the front end side of the contact lever 12 is pushed up, and the trigger valve stem 58 of the trigger valve 50 is pushed up by the pushing up of the contact lever 12, and the trigger valve 50 is operated. When the trigger valve 50 is actuated, the O-rings 58a and 58b move upward as shown in FIG. be. The pilot valve 54 is pushed down by the compressed air inside the main chamber 5 against the elastic force of the compression spring 57 , and the lower surface of the pilot valve 54 contacts the upper surface of the cap 56 . Thereby, the passage 53 and the exhaust passage 59 are communicated with each other.

However, when the timer valve 80 times out, the path between the second connection path 39 and the third connection path 49 is cut off by the control valve 40 shown in FIG. It is in a state in which it communicates with the chamber 5 . Therefore, the compressed air in the head valve chamber 38 remains inside the head valve chamber 38 without being discharged to the outside through the exhaust passage 59 provided in the trigger valve 50 . As a result, when the timer valve 80 times out, the head valve 30 does not operate even when the operator pulls the trigger lever 11 and presses the contact arm 14 against the workpiece. Therefore, no driving operation is performed after the timer valve 80 times out.

As described above, according to the first embodiment, the first chamber 81 of the cylinder 90 for storing the atmosphere for operating the timer valve 80 is configured as a closed space isolated from other spaces, and the timer valve 80 Since the atmosphere used for operating the timer valve 80 is not supplied from the outside, it is possible to prevent oil, dust, etc. from entering the first chamber 81 of the timer valve 80 . As a result, the specified time of the timer valve 80 can be measured accurately and with high precision, and abnormal operation due to adherence of foreign matters such as oil and dust to the timer valve 80 can be prevented.

<Second Embodiment>
The timer valve 280 according to the second embodiment employs a configuration different from that of the timer valve 80 according to the first embodiment. Similarly, the control valve 240 and the switch valve 70 according to the second embodiment also employ configurations different from those of the control valve 40 and the switch valve 70 according to the first embodiment. Since other configurations, functions, and operations of the nailing machine 200 are the same as those of the nailing machine 100 of the first embodiment, detailed description thereof will be omitted.

[Configuration example of nailing machine 200]
FIG. 11 is a side cross-sectional view of nailing machine 200 according to the second embodiment. FIG. 12 is a side sectional view of the timer valve 280 according to the second embodiment. FIG. 13 is a side sectional view of the control valve 240 according to the second embodiment.

The nailing machine 200 is an example of a pneumatic tool, and includes a striking mechanism 20 having a piston 24 slidable inside a cylinder 26, a driver 22 attached to the piston 24 for driving a nail into a member to be nailed, and a striking mechanism 20. A main chamber 5 supplied with compressed air for driving the mechanism 20, a head valve 30 driving the striking mechanism 20 using the compressed air supplied to the main chamber 5, and a trigger valve 50 operating the head valve 30. and The nailing machine 200 also includes a control valve 240 that disables the operation of the head valve 30 that operates in accordance with the operation of the trigger valve 50, and a timer that disables the operation of the head valve 30 by operating the control valve 240. A valve 280 and a switch valve 70 that operates the timer valve 280 based on the operation of the trigger lever 11 are provided.

As shown in FIG. 11 , the switch valve 70 is arranged adjacent to the rear side of the trigger valve 50 and operates the timer valve 280 based on the operation of the trigger lever 11 . The switch valve 70 has a cylinder 72 and a switch valve stem 74 .

The cylinder 72 is a cylindrical body having a hollow extending in the vertical direction, and accommodates the switch valve stem 74 so as to be slidable in the vertical direction. A first passage 72 a communicating with the main chamber 5 is formed on the upper side of the cylinder 72 . One end of the fourth connection path 79 communicates with a substantially intermediate position of the cylinder 72 , and the other end of the fourth connection path 79 communicates with the timer valve 280 . A second passage 72b is formed below the fourth connection passage 79 of the cylinder 72 and communicates with the outside of the housing 1a at atmospheric pressure.

The switch valve stem 74 communicates the fourth connecting passage 79 and the second passage 72b when the trigger lever 11 is not pulled, and the O-ring 74a connects the first passage 72a and the fourth connecting passage 79. close. On the other hand, when the trigger lever 11 is pulled, the switch valve stem 74 is pushed up by the contact lever 12 against the elastic force of the compression spring 76, thereby communicating the first passage 72a and the fourth connection passage 79. , the O-ring 74b closes the path between the fourth connecting path 79 and the second passage 72b.

As shown in FIGS. 11 and 12, the nailing machine 200 operates the control valve 240 when the trigger lever 11 is pulled and the contact arm 14 is pressed against the nailed member after a specified time has elapsed. A timer valve 280 is provided to override the driving action.

The timer valve 280 is provided outside the housing 1a, is connected to the control valve 240 via a connection path 249 (to be described later), is connected to the switch valve 70 via a fourth connection path 79, and is connected to the switch valve 70 via the first connection path 29. connected to the blowback chamber 28.

The timer valve 280 has a valve housing 281, a timer valve stem 282, a piston 285, and a sealing member 286, as shown in FIG. The valve housing 281 has a first accommodation portion 281 a that accommodates the timer valve stem 282 , a second accommodation portion 281 b that accommodates the piston 285 , a third accommodation portion 281 c that accommodates the seal member 286 , and the control valve 240 . A space portion 281d is provided for storing compressed air for measuring a specified time until operation.

One end of the fourth connection path 79 communicates with the lower end side of the first accommodation section 281a, and the compressed air of the main chamber 5 can be supplied to the inside of the first accommodation section 281a via the fourth connection path 79. It's like One end of the first passage 281u communicates with the upper end side of the first accommodating portion 281a, and the other end of the first passage 281u communicates with the space 281d.

One end of the third passage 281w communicates with the upper end of the second housing portion 281b, and the other end of the third passage 281w communicates with one end of the first connection passage 29. Compressed air in the blowback chamber 28 can be supplied to the inside of the second accommodation portion 281b through the second accommodation portion 281b.

One end of the second passage 281v communicates with the lower end side of the third housing portion 281c, and the other end of the second passage 281v communicates with one end of the fourth connection passage 79, thereby connecting the second passage 281v. Compressed air in the main chamber 5 can be supplied to the inside of the third accommodating portion 281c through the air gap.

A fifth passage 281y communicating with the outside of the valve housing 281 is provided between the second accommodating portion 281b and the third accommodating portion 281c. A sixth passage 281z is provided between the first passage 281u and the second housing portion 281b to communicate therebetween. Between the third passage 281w and the first accommodating portion 281a, a fourth passage 281x branching from the middle of the third passage 281w is provided.

The timer valve stem 282 is a substantially cylindrical body that extends vertically, and is arranged so as to be vertically slidable along the inner wall of the first housing portion 281a. A timer valve stem 282 is biased downward by a compression spring 284 . The compression spring 284 is interposed between a support portion 281 s provided on the valve housing 281 and the upper side of the timer valve stem 282 and expands according to the compressed air supplied from the main chamber 5 .

The timer valve stem 282 has a throttle portion 282a that controls the flow rate of compressed air used to operate the control valve 240. As shown in FIG. The throttle portion 282a is formed continuously from the upper end portion of the cylindrical timer valve stem 282, and is formed of a tapered cylindrical body whose outer diameter gradually decreases upward. The squeezed portion 282a rises inside the first accommodating portion 281a by the compressed air that flows in response to the pulling operation of the trigger lever 11, and is fitted (engaged) with the squeezed portion 281u1 provided on the lower end side of the first passage 281u. ) to close the first passage 281u. That is, the gap between the drawn portion 282a and the drawn portion 281u1 is closed. The narrowed portion 281u1 is configured such that the passage diameter increases from the upper end side to the lower end side, and has a shape in which the narrowed portion 282a can be fitted. At this time, the peripheral surface of the throttled portion 282a is in close contact with the wall surface of the throttled portion 281u1. It is configured to form a minute gap that can pass through. Accordingly, by adjusting the area of the gap between the throttled portion 282a and the throttled portion 281u1, the flow rate of the compressed air flowing into the space portion 281d can be regulated to be constant.

A space portion 281d of the valve housing 281 is configured by a space having a volume capable of storing a predetermined amount of compressed air, one end of the first passage 281u is communicated with the rear wall, and a connection passage 249 is connected with the front wall. One end communicates. The volume of the space portion 281d is designed based on a prescribed time (timeout) for operating the control valve 240 by the timer valve 280. As shown in FIG. Therefore, in the present embodiment, the specified time by the timer valve 280 is determined based on the volume of the space portion 281d and the area of the minute gap formed between the throttled portion 282a and the throttled portion 281u1. Note that the volume of the space portion 281d can also take into account the volume of the connection path 249, the first passage 281u, and the like.

The piston 285 has a cylindrical body 285a having substantially the same diameter as the inner diameter of the second housing portion 281b, and a pressing portion 285b that is smaller than the diameter of the cylindrical body 285a and protrudes downward from the second housing portion 281b. The cylindrical body 285a of the piston 285 descends inside the second housing portion 281b in accordance with the compressed air supplied from the blowback chamber 28 when the striking mechanism 20 performs a striking operation. The pressing portion 285b presses the sealing member 286 arranged on the lower side as the cylindrical body 285a descends.

The seal member 286 is made of a resin material such as rubber, and is arranged inside the third accommodation portion 281c provided below the second accommodation portion 281b. The seal member 286 is integrally attached to the attachment member 287 and biased upward by a compression spring 288 . The compression spring 288 is interposed between the mounting member 287 and the inner bottom surface of the third accommodating portion 281c, and expands and contracts according to the pressure of the piston 285. As shown in FIG.

When pressed by the piston 285, the sealing member 286 causes the sixth passage 281z communicating with the space 281d and the fifth passage 281y communicating with the outside to communicate with each other, thereby discharging the compressed air inside the space 281d to the outside. On the other hand, when the piston 285 is not pressed, the sealing member 286 communicates the second passage 281v communicating with the main chamber 5 with the sixth passage 281z communicating with the space 281d, thereby allowing the compressed air in the main chamber 5 to flow into the space. 281d.

The nailing machine 200, as shown in FIGS. 11 and 13, has a control valve 240 that disables the operation of the trigger valve 50 after the specified time of the timer valve 280 has elapsed. Control valve 240 has a cylinder 241 , a control valve piston 242 and a control valve stem 245 .

The cylinder 241 is a cylindrical body having an open upper side and a bottom surface on the lower side. One end of a connection path 249 communicating with a timer valve 280 communicates with the lower rear wall of the cylinder 241 .

The control valve piston 242 is arranged inside the cylinder 241 and slides vertically along the inner wall of the cylinder 241 . An O-ring 243 is attached to a mounting portion 242 a provided on the lower side of the control valve piston 242 to ensure close contact with the inner wall of the cylinder 241 . The control valve piston 242 is biased downward by a compression spring 244 . The compression spring 244 is interposed between the attachment portion 242 a and the support portion 1 d that constitutes the housing 1 a and expands and contracts according to the compressed air supplied from the timer valve 280 . The control valve piston 242 rises from the bottom surface inside the cylinder 241 when compressed air is supplied through a connecting passage 249 between the bottom surface of the control valve piston 242 and the bottom surface inside the cylinder 241 . On the other hand, the control valve piston 242 descends from the raised position inside the cylinder 241 when the compressed air between the bottom surface of the control valve piston 242 and the bottom surface inside the cylinder 241 is exhausted through the connecting passage 249. Abut on the bottom surface.

The control valve stem 245 is arranged in a housing portion 1e formed in the housing 1a on the upper side of the control valve piston 242. As shown in FIG. The control valve stem 245 is biased downward by a compression spring 247 and the lower surface of the control valve stem 245 is in contact with the upper surface of the control valve piston 242 . The compression spring 247 is interposed between the top surface inside the accommodating portion 1e and the upper surface of the control valve stem 245, and expands and contracts according to the upward or downward movement of the control valve piston 242.

Two O-rings 246a and 246b are attached along the circumference of the control valve stem 245 at approximately the middle position in the vertical direction. The O-ring 246 a opens or closes the path between the second connection path 39 and the third connection path 49 to connect or block the second connection path 39 and the third connection path 49 . The O-ring 246b opens or closes the path between the second connection path 39 and the path 241a to connect or block the second connection path 39 and the path 241a.

[Example of operation of nailer 200]
Next, an example of the driving operation of the nailing machine 200 according to the second embodiment will be described. 14 to 19 are diagrams showing the driving operation of the nailing machine 200 according to the second embodiment.

Compressed air is supplied to the interior of the main chamber 5 when an air hose is connected to the air plug 8 of the nailing machine 200 shown in FIG. As shown in FIG. 14, in the initial state before the switch valve 70 is activated, the first passage 72a and the fourth connection passage 79 are blocked by the O-ring 74a. is not supplied to the timer valve 280. On the other hand, the space portion 281d of the timer valve 280 communicates with the outside of the atmospheric pressure via the fourth connection passage 79 and the second passage 72b of the switch valve .

As shown in FIG. 15, when the operator pulls the trigger lever 11, the switch valve stem 74 of the switch valve 70 is pushed up by the contact lever 12, and the switch valve 70 is operated. When the switch valve 70 operates, the O-ring 74a also moves upward, and the first passage 72a of the switch valve 70 and the fourth connection passage 79 communicate with each other. Along with this, the compressed air in the main chamber 5 is supplied to the first accommodating portion 281a and the second passage 281v of the timer valve 280 via the first passage 72a, the inside of the switch valve 70, and the fourth connection passage 79. be done.

When the timer valve stem 282 is pressed upward by the compressed air that has flowed into the first accommodation portion 281a, the timer valve stem 282 rises in the first accommodation portion 281a at once and reaches the top dead center. As a result, the narrowed portion 282a fits into the narrowed portion 281u1 of the first passage 281u. At this time, a minute gap through which the fluid can pass is formed between the peripheral surface of the narrowed portion 282a and the wall surface of the narrowed portion 281u1.

In addition, the compressed air that has flowed into the second passage 281v passes through the third accommodating portion 281c, the sixth passage 281z, the gap between the throttle portion 282a and the throttled portion 281u1, and the first passage 281u, and enters the space portion 281d. flow into Compressed air is gradually accumulated inside the space 281d, and the pressure inside the space 281d increases. As a result, the specified time is started until the control valve 240 is actuated.

As shown in FIG. 16, when the contact arm 14 is pressed against the driven member while the trigger lever 11 is pulled and before the timer valve 280 times out, the pressing member 15 is pushed up. Accordingly, the front end side of the contact lever 12 is pushed up, and the trigger valve stem 58 of the trigger valve 50 is pushed up by pushing up the contact lever 12, and the trigger valve 50 is operated.

When the trigger valve 50 is actuated, the O-rings 58a and 58b also move upward as shown in FIG. be. The pilot valve 54 is pushed down by the compressed air in the main chamber 5 against the elastic force of the compression spring 57 , and the lower surface of the pilot valve 54 contacts the upper surface of the cap 56 . As a result, the passage 53 communicates with the exhaust passage 59, and the compressed air in the head valve chamber 38 passes through the second connection passage 39, the control valve 240, the third connection passage 49, the trigger valve 50 and the exhaust passage 59 to the atmosphere. It is exhausted inside (outside).

When the compressed air in the head valve chamber 38 is exhausted, the movable portion 34 of the head valve 30 is pushed up by the compressed air in the main chamber 5 as shown in FIG. By opening, the compressed air inside the main chamber 5 flows into the piston upper chamber 24a, and the piston 24 descends inside the cylinder 26 rapidly.

As shown in FIG. 17, when the piston 24 is further lowered, the driver 22 (see FIG. 11) connected to the piston 24 drives the nail into the driven member. Also, when the piston 24 descends to the lower side inside the cylinder 26 , the compressed air inside the cylinder 26 flows into the blowback chamber 28 through the small hole 27 . The compressed air that has flowed in passes through the first connection path 29 and the third passage 281w of the timer valve 280, and flows into the second housing portion 281b.

The piston 285 is urged downward by the inflowing compressed air, and moves downward inside the second housing portion 281b to push the seal member 286 downward. The seal member 286 is pushed down against the elastic force of the compression spring 288 . As a result, the fifth passage 281 y communicating with the atmosphere and the control valve 240 communicate with each other via the sixth passage 281 z, the first passage 281 u, the space 281 d and the connecting passage 249 .

In addition, the compressed air that has flowed into the third passage 281w also flows into the inside of the first accommodation portion 281a via the fourth passage 281x. The timer valve stem 282 descends to the initial position (bottom dead center) of the first accommodating portion 281a by the inflowing air and the biasing force of the compression spring 284 . In the present embodiment, the pressure receiving area of the compressed air at the position where the fourth passage 281x of the timer valve stem 282 is provided is set larger than the pressure receiving area of the compressed air at the lower end side of the timer valve stem 282 . Therefore, the timer valve stem 282 is lowered by receiving the compressed air flowing from the blowback chamber 28 via the fourth passage 281x. As a result, the gap between the throttled portion 282a provided on the upper end side of the timer valve stem 282 and the throttled portion 281u1 is expanded.

In this state, the compressed air inside the space 281d and the compressed air below the control valve 240 flow back to the outside through the fifth passage 281y and are exhausted. At this time, in the present embodiment, the compressed air flowing from the control valve 240 and the space portion 281d hits the peripheral surface of the throttled portion 282a and the wall surface of the throttled portion 281u1 in the gap between the throttled portion 282a and the throttled portion 281u1. while passing vigorously. As a result, impurities such as dust and oil adhering to the peripheral surface of the narrowed portion 282a are removed.

As shown in FIG. 18, when the contact arm 14 is not pressed against the member to be driven within a specified time after the operation of the timer valve 280 shown in FIG. actuates the control valve 240 .

Specifically, when the compressed air inside the space 281 d of the timer valve 280 reaches a specified pressure value, part of the compressed air will flow between the lower surface of the control valve piston 242 and the inner bottom surface of the cylinder 241 . influx. Along with this, the control valve piston 242 rises from the bottom surface inside the cylinder 241, and the control valve stem 245 is also pushed up. O-rings 246a and 246b are also moved upward by pushing up the control valve stem 245, and while the second connection path 39 and the passage 241a are communicated, the second connection path 39 and the third connection path 49 are blocked. . As a result, the head valve chamber 38 switches from the state of communication with the trigger valve 50 to the state of communication with the main chamber 5 .

As shown in FIG. 19, when the contact arm 14 is pressed against the member to be driven after the timer valve 280 has timed out while the trigger lever 11 is being pulled by the operator, the pressing member 15 is interlocked therewith. is pushed up. When the front end side of the contact lever 12 is pushed up by pushing up the pressing member 15, the trigger valve stem 58 of the trigger valve 50 is pushed up, and the trigger valve 50 is operated. The operation of the trigger valve 50 causes the O-rings 58a and 58b to move upward as shown in FIG. exhausted. The pilot valve 54 is pushed down by the compressed air in the main chamber 5 against the elastic force of the compression spring 57 , and the lower surface of the pilot valve 54 contacts the upper surface of the cap 56 . Thereby, the passage 53 and the exhaust passage 59 are communicated with each other.

However, when the timer valve 280 times out, the control valve 240 blocks the second connection path 39 and the third connection path 49, while allowing the second connection path 39 and the main chamber 5 to communicate with each other. . Therefore, the compressed air inside the head valve chamber 38 is not discharged to the outside through the exhaust passage 59 provided in the trigger valve 50 and remains inside the head valve chamber 38 . As a result, when the timer valve 280 times out, the head valve 30 does not operate even when the operator pulls the trigger lever 11 and presses the contact arm 14 against the driven member. Therefore, no driving operation is performed after timer valve 280 times out.

As described above, according to the second embodiment, the control valve 240 is inserted into the gap between the squeezed portion 282a and the squeezed portion 281u1 each time the hammering mechanism 20 of the nailing machine 200 performs one driving operation. Since the compressed air used for operating is reversed from the space portion 281d, impurities such as dust and oil attached to the throttle portion 282a and the like can be reliably removed. As a result, the specified time of the timer valve 280 can be measured accurately and with high accuracy, and abnormal operation due to adherence of foreign matters such as oil and dust to the timer valve 280 can be prevented.

In addition, in the second embodiment, compressed air from the blowback chamber 28 is supplied to the timer valve stem 282 in conjunction with the striking operation by the striking mechanism 20 to move the timer valve stem 282 to the lower side of the first accommodating portion 281a. , the squeezed portion 282a is separated from the squeezed portion 281u1, so that the area of the gap between the squeezed portion 282a and the squeezed portion 281u1 can be expanded. As a result, when the compressed air in the space 281d flows to the throttled portion 282a, the area of the compressed air that hits the peripheral surface of the throttled portion 282a and the wall surface of the throttled portion 281u1 can be increased. can be easily eliminated.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes various modifications to the above-described embodiments within the scope of the present invention. Specifically, in the above embodiments, nailing machines 100 and 200 have been described as examples of pneumatic tools, but the present invention is not limited to this. For example, the present invention can be applied to a screw tightening tool, a screw driving tool, etc. as pneumatic tools.

Further, in the above-described first and second embodiments, an example in which the control valves 40 and 240 are arranged between the head valve 30 and the trigger valve 50 has been described, but the present invention is not limited to this. For example, control valves 40 and 240 may be located inside trigger valve 50 . Further, in the first and second embodiments, the passage between the head valve 30 and the trigger valve 50 is blocked by the control valves 40 and 240, but the structure is not limited to this. For example, a structure in which the control valves 40 and 240 mechanically disable the operation of the head valve 30 can be employed. In the first embodiment, the control valve 40 is pressed and operated by the timer valve 80 when the specified time by the timer valve 80 has passed, and when the predetermined time has passed, the pressure between the head valve 30 and the trigger valve 50 is increased. Although the configuration is such that the passage is completely blocked, the configuration is not limited to this. For example, it is possible to employ a configuration in which the control valve 40 is operated in a state of being pressed by the timer valve 80 from the first stage, and the passage between the head valve 30 and the trigger valve 50 is completely blocked after a predetermined time has elapsed. . Furthermore, in the above-described first and second embodiments, the control valves 40 and 240 are configured to be actuated by pressing. may be configured.

1 main body 4 grip part 5 main chamber (first chamber)
11 trigger lever (trigger)
20 striking mechanism (driving mechanism)
22 driver 24 piston 26 cylinder 28 blowback chamber (second chamber)
30 head valve 40 control valve 50 trigger valve 80 timer valve 81 first chamber (accommodating section)
84 1st timer piston (valve element)
85 First piston shaft (valve element)
88 throttle portion 89 compression spring 100, 200 nailer (pneumatic tool)
282 Timer valve stem 281u1 Squeezed portion 282a Squeezed portion

Claims (8)

a drive mechanism driven by the pneumatic pressure of compressed air;
a chamber supplied with compressed air for driving the drive mechanism;
a head valve that drives the drive mechanism using compressed air supplied to the chamber;
a trigger valve that operates the head valve;
a control valve that disables the operation of the head valve that operates in accordance with the operation of the trigger valve;
a timer valve that operates based on the operation of a trigger, and disables the operation of the head valve by operating the control valve at a predetermined timing;
The timer valve has an accommodation portion for storing air for operating the timer valve,
wherein the chamber and the housing portion are configured as spaces isolated from each other,
pneumatic tools. The storage unit is isolated from the outside air,
A pneumatic tool according to claim 1. The timer valve
a valve body that moves inside the housing and acts on the control valve;
a throttle portion that regulates the flow of air generated by the movement of the valve body;
having
A pneumatic tool according to claim 1 or 2. a main body provided with the drive mechanism;
a grip portion attached to a side portion of the main body and extending in a direction crossing the moving direction of the piston of the drive mechanism;
The timer valve is arranged inside the grip part,
A pneumatic tool according to any one of claims 1 to 3. a main body provided with the drive mechanism;
a grip portion attached to a side portion of the main body and extending in a direction crossing the moving direction of the piston of the drive mechanism;
The valve body is arranged movably along the extending direction of the grip portion,
A pneumatic tool according to claim 3. a drive mechanism driven by the pneumatic pressure of compressed air;
a first chamber supplied with compressed air for driving the drive mechanism;
a head valve that drives the drive mechanism using the compressed air supplied to the first chamber;
a trigger valve that operates the head valve;
a control valve that disables the operation of the head valve that operates in accordance with the operation of the trigger valve;
a timer valve that operates based on the operation of a trigger, and disables the operation of the head valve by operating the control valve at a predetermined timing;
The timer valve has a throttle portion for regulating the flow of compressed air for operating the control valve, and the compressed air flows through the throttle portion at a predetermined timing interlocked with the driving operation of the drive mechanism.
pneumatic tools. The narrowed portion regulates the flow of the compressed air by displacing the area of the gap between the narrowed portion and the narrowed portion;
expanding the area of the gap when the compressed air is supplied in conjunction with the driving operation;
A pneumatic tool according to claim 6. a second chamber containing compressed air for returning the piston of the drive mechanism to its initial position after the driving action;
The narrowed portion expands the area of the gap by moving with respect to the narrowed portion by the compressed air supplied from the second chamber.
A pneumatic tool according to claim 7.

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