JPH0586478U - Operation mode switching device for nailer - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the switching operation part for changing between continuous and single shot modes from moving due to impact during nailing. A cam 60 for contacting an intermediate portion of the contact arm and switching the contact arm between two sliding strokes is provided in a switching operation portion 57 of the operation mode switching device of the nail driving machine. The cam loosely fits on the shaft 59 and is urged toward the protrusion 63 on the shaft by the elastic member 61. The cam is provided with a first engaging portion 64 and a second engaging portion which are selectively engaged with the protrusion so as to be out of phase with each other by 90 °. The operation lever 62 is connected to the cam. When switching between modes, slide on the shaft against the elastic member of the cam and
Rotational movement about an axis of 0 ° is required. Therefore, the cam or the like of the switching operation unit 57 does not move freely even by an impact when nailing.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a switching device for switching a nailing machine to either continuous driving or single-shot driving mode.

[0002]

[Prior Art]

 Some nailing machines are capable of switching between continuous hammering and single hammering as shown in Japanese Utility Model Publication No. 1-18294 or FIG.

In the continuous striking mode, as shown in FIG. 11, the switching lever 2 is separated from the contact arm 1 to be applied to the work surface where the nail is to be driven, and the contact arm 1 is moved to the front position by the compression coil spring 3. It can be obtained by moving to. In this mode, the nail 4 can be continuously nailed as many times as necessary by simply pulling the trigger 4 and pressing the contact arm 1 against the work surface.

In FIG. 11, the contact arm 1 extends from the tip of the nail guide cylinder 5 to the vicinity of the rotary shaft 6 of the trigger 4, and is constantly urged forward by the compression coil spring 3. Then, when the trigger 4 is pulled, the upper part of the contact lever 8 connected to the lower part of the trigger 4 via the rotary shaft 7 rotates counterclockwise and comes into contact with the rear end 1b of the contact arm 1. When the front end 1a of the contact arm is pressed against the work surface in that state, the contact arm 1 moves rearward against the compression coil spring 3, and the rear end 1b pushes the upper portion of the contact lever 4 rearward. As a result, the stem 10 of the trigger valve 9 retracts, and compressed air flows into the cylinder 12 for driving the driver 11. The driver 11 moves forward by the supply of compressed air, and drives the nail sent from the nail supply unit 13 from the guide cylinder 5 toward the work surface.

After that, when the contact arm 1 is separated from the work surface, the restoring force of the compression coil spring 3 moves the contact arm 1 forward to release the pressing of the contact lever 8. As a result of the stem 10 of the trigger valve 9 also being released, the spring 14 in the trigger valve 9 returns it to its original position, cutting off the supply of compressed air to the cylinder 12 side. The driver 11 returns to its original position by the action of the compressed air in the return air chamber 15.

The next nail driving can be performed immediately by simply pressing the contact arm 1 against the work surface while pulling the trigger 4. In the single shot driving mode, the switching lever 2 shown in FIG. 11 is slid upward to engage the engaging piece 1c of the contact arm 1, and the contact arm 1 is moved to a position slightly rearward against the compression coil spring 3. It can be obtained by moving it. This mode is for preventing the next nail from being hit unless the trigger 4 is returned after pulling the trigger 4.

When the front end 1a of the contact arm 1 is pressed against the work surface and the trigger 4 is pulled under the mode, the contact lever 1 rotates integrally with the trigger 4 and the stem 10 of the trigger valve 9 moves backward. Push. As a result, compressed air flows into the cylinder 12, and the driver 11 moves forward by the compressed air to drive the nail out of the guide cylinder 5 toward the work surface.

After that, even if the contact arm 1 is separated from the work surface, the contact lever 8 is supported by the rear end 1b of the contact arm 1 and still pushes the stem 10, so that the driver 11 maintains the forward state. However, when the trigger 4 is released, the stem 10 of the trigger valve 9 is released and the spring 14 in the trigger valve 9 restores the original position. As a result, the supply of compressed air into the cylinder 12 is cut off, and the driver 11 is returned to the rear by the compressed air in the return air chamber 15.

[0009]

[Problems to be solved by the device]

 However, the above-mentioned conventional operation mode switching device for a nail driving machine, in the former Japanese Utility Model Publication No. 1-18294, only has the switching lever elastically contacting the trigger, so There is a drawback that the switching lever moves due to the impact at the time. Moreover, since the switching lever is provided behind the trigger, there is a problem that it is difficult to put a finger on the trigger and the operation is difficult.

Further, in the latter one shown in FIG. 11, since the switching lever 2 is of a sliding type and is locked by the ball 17 urged by the spring 16, the nail is fixed. There is a problem that it will move freely due to the impact of hitting.

The present invention aims to solve such problems.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a contact arm for converting a turning stroke of a contact lever that comes into contact with a stem of a trigger valve of a nailing machine into either continuous hammering or single shot hammering, and the contact arm. Between the two sliding strokes corresponding to the two rotational strokes of the contact lever, and the operation mode of the nailing machine including a switching operation portion arranged in front of the trigger of the nailing machine. In the changeover device, the changeover operation portion comes into contact with an intermediate portion of the contact arm and switches the contact arm between the two sliding strokes. An elastic member that urges the cam in the central axis direction of the shaft, an operation lever connected to the cam, and the cam on the shaft serve as the elastic member. And a protrusion fixed to the urging side, and selectively engaged with the protrusion in accordance with a sliding operation and a rotating operation of the cam along the shaft when switching the sliding stroke. A structure is used that is composed of first and second engaging portions provided on the cam.

[0013]

[Action]

 When switching from one mode of continuous striking or single-shot striking to the other mode, the protrusion is moved to the first engagement position by holding the rotation operation lever and sliding the cam along the shaft against the elastic member. It is disengaged from either the joining portion or the second engaging portion. With this, the cam becomes rotatable, and then the cam is rotated around the shaft while holding the operation lever so that the other engaging portion faces the protrusion. Then, when the operating lever is released, the cam automatically slides along the axis toward the protrusion due to the urging of the elastic member, and the other engaging portion and the protrusion are engaged.

As a result, the cam switches the contact arm to one of two sliding strokes. If this new mode is continuous striking, the rotation stroke of the contact lever is restricted to that for continuous striking, and continuous striking is possible by operating the trigger and contact arm.

On the other hand, if the new mode is a single shot, the rotation stroke of the contact lever is restricted to a single shot, and the single shot can be made by operating the trigger and the contact arm.

The impact of this single shot is also applied to the switching operation portion, but the engagement portion engages with the protrusion fixed to the shaft, and the engagement state is maintained by the elastic member. There is no risk that the will rotate naturally to switch modes.

Further, since the operation lever of the switching operation unit is provided in front of the trigger, it is easy to put a finger on it and the operation becomes easy.

[0018]

【Example】

 Hereinafter, preferred embodiments of a nailing machine according to the present invention will be described with reference to the drawings. As shown in FIG. 1, this nailing machine has a hollow housing 18 which is its main body.

A cylinder 19 is housed in the housing 18, and a piston 23 holding a driver 22 for nail driving is housed in the cylinder 19 so as to be movable back and forth.

An empty space is provided between the housing 18 and the cylinder 19, and the empty space is divided into front and rear by a partition wall 26. The front room serves as a return air chamber 28 which communicates with the inside of the cylinder 19 through a ventilation hole 27 penetrating the cylinder wall, and the rear room serves as an air chamber 29 for storing compressed air. There is. The air chamber 29 extends into a handle portion 30 provided on the lower side of the housing 18, and compressed air is supplied from this vacant chamber.

A slide valve 31 for selectively connecting the inside of the cylinder 19 to the air chamber 29 and the atmosphere is interposed between the rear end of the housing 18 and the rear end of the cylinder 19. On the other hand, a cylindrical body 32 is provided at the rear end of the housing 18, and an annular groove for guiding sliding of the slide valve 31 is formed between the cylindrical body 32 and the housing wall.

The sliding valve 31 has a substantially cylindrical shape, and its front edge opens and closes the cylinder 19 by coming into contact with and separating from the valve seat 33 at the rear edge of the cylinder 19. An O-ring 34 for airtightness is attached to the rear part of the annular groove, and a valve chamber 36 is provided on the bottom side of the annular groove. Further, a compression coil spring 35 is provided in the annular groove, and the slide valve 31 is provided between the cylinder 19 and the air chamber 29 by the pressure of the compressed air introduced into the compression coil spring 35 and the valve chamber 36. Is shut off and the inside of the cylinder 19 is communicated with the atmosphere.

A vent passage 37 connects the valve chamber 36 and the air chamber 29. The air passage 37 is selectively connected to the inside of the air chamber 29 or the outside of the housing 18 by a trigger valve 38 described later.

Therefore, when the trigger valve 38 operates so as to bring the ventilation passage 37 into communication with the outside of the housing 18, the inside of the valve chamber 36 becomes the same as the atmospheric pressure, so that the sliding valve 31 is connected to the front edge of the sliding valve 31. The compressed air in the air chamber 29 is separated from the cylinder 19 against the compression coil spring 35. As a result, the sliding valve 31 opens the cylinder 19 and shuts off the inside of the cylinder 19 from the atmosphere, and the piston 23 inside the cylinder 19 receives the supply of compressed air and moves from the back to the front. ..

On the contrary, when the trigger valve 38 operates so as to connect the ventilation passage 37 to the air chamber 29, compressed air flows into the valve chamber 36, and the slide valve 31 is moved to the cylinder 19 side together with the compression coil spring 35. Acts to move. As a result, the sliding valve 31 closes the cylinder 19 and allows the inside of the cylinder 19 to communicate with the atmosphere. As a result of the supply of compressed air being cut off, the piston 23 in the cylinder 19 is returned from the front to the rear by the force of the compressed air in the return air chamber 28.

The trigger valve 38 is attached to the base of the handle portion 30 and is configured as shown in FIG. The trigger valve 38 has a valve cylinder 39 fixed laterally on the housing 18 side. The rear end of the valve cylinder 39 is closed, and the front end is closed by an end plate 41 having an exhaust hole 40. An air supply / exhaust hole 42 connected to the starting end 37a of the air passage 37 and an air supply hole 43 connected to the air chamber 29 are formed in the center of the valve cylinder 39 at predetermined intervals in the front and rear. There is.

A stem 44 is slidably inserted in the valve cylinder 39 in the front-rear direction. The stem 44 is biased forward by a compression coil spring 45 housed in the valve cylinder 39, and its front portion penetrates the center of the end plate 41 and projects outward. Further, first and second piston portions 46 and 47 are formed at a portion of the stem 44 that has entered the valve cylinder 39.

Two O-rings 48, 49 are attached to the front side first piston portion 46 at a predetermined interval, and when the piston portion 46 is at the top dead center (FIGS. 5 and 6). A rear O-ring 49 connects the air supply hole 43 to the air supply / exhaust hole 42, and when the piston portion 46 is at the bottom dead center (FIG. 7), the front O-ring 48 connects the exhaust hole 40. The air supply / exhaust holes 42 are communicated with each other.

An O-ring 50 is also fitted in the second piston portion 47 on the rear side, and the O-ring 50 connects the air supply hole 43 and the stem central hole during the entire stroke of the piston portion 47. I refuse.

The left side of the stem 44 projects out of the valve cylinder 39, and a trigger 51 is provided in front of that portion. The trigger 51 is pivotally supported by a pin 52 on the front side of the position where the valve cylinder 39 of the housing 18 is located, and is rotated downward. A contact lever 53 is rotatably supported by a pin 54 at the lower portion of the trigger 51, and is rotatable between the trigger 51 and the stem 44 in an upward direction.

As shown in FIG. 1, the front end plate 20 that closes the front end of the housing 18 is connected to a guide cylinder 54 that serves as a passage for the driver 22. A nail supply portion 55 is connected to the middle of the guide cylinder 54, and the guide cylinder 54 also serves as a passage for guiding the nail sent from the nail supply portion 55.

A contact arm 56 is attached to the guide cylinder 54 for converting the rotation stroke of the contact lever 53 that comes into contact with the stem 44 of the trigger valve 38 into either continuous stroke or single shot stroke. The contact arm 56 extends from the tip of the guide cylinder 54 to the vicinity of the pin 52 of the trigger 51, and the front end portion 56a thereof protrudes ahead of the guide cylinder 54 and can contact the work surface, and the rear end portion 56b. Can contact the upper part of the contact lever 53.

The contact arm 56 includes an engaging piece 56 c between the trigger 51 and the nail supply portion 55. The engagement piece 56c is constantly urged by a compression coil spring 58 toward a switching operation portion 57, which will be described later, attached to a housing portion near the nail supply portion 55. Therefore, the contact arm 56 is always biased forward, and stops at the position where the engagement piece 56c abuts the switching operation portion 57 side.

The switching operation portion 57 is for switching the contact arm 56 between two different sliding strokes corresponding to the two rotational strokes of the contact lever 53, and is shown in FIGS. 2 to 4. And a cam 60 loosely fitted to a shaft 59 on the housing 18 side that abuts on an engaging piece 56c at an intermediate portion of the contact arm 56 to switch the contact arm 56 between the two types of sliding strokes, and the cam 60. An elastic member 61 for urging 60 in the direction of the central axis of the shaft 59, an operation lever 62 connected to a cam 60, and a cam 60 on the shaft 59 are fixed to the side urged by the elastic member 61. The projection 63 and the cam 60 that selectively engages with the projection 63 in accordance with a sliding operation and a rotating operation along the shaft 63 of the cam 60 when switching the sliding stroke. The first and second engaging portions 64 and 65 are provided.

The shaft 63 of the cam 60 is fixed to the lower surface of the housing 18 via a bracket 66 so that its center axis extends in the left-right direction. The cam 60 includes a flat portion 60a and a flat portion 60b orthogonal to the flat portion 60a, and one of them comes into contact with the engaging piece 56c of the contact arm 56. When the flat portion 60a comes into contact with the engagement piece 56c, the mode is a continuous striking mode, the contact arm 56 stops at the frontmost position as shown in FIG. 1, and the rear end portion 56b thereof is as shown in FIG. Stop just below the pin 52 of the trigger 51. When the flat portion 60b comes into contact with the engaging piece 56c, the single shot mode is set, and as shown in FIG. 9, the contact arm 56 is stopped at a position slightly rearward from that in the continuous shot mode, and the rear end portion is formed. 56b goes over the pin 52 of the trigger 51 and approaches by the contact lever 53.

The elastic member 61, which is a compression coil spring in this case, is attached to the shaft 59 and constantly presses the cam 60 to the left side. The operation lever 62 projects leftward from the side surface of the flat portion 60b of the cam 60, and projects outward from the left bracket 66 so that it can be easily operated by a finger.

The protrusion 63 is a pin and is fixed so as to penetrate the shaft 59 at a right angle. The first engagement portion 64 is formed as step portions 64a and 64b integrally provided with the cam 60 at a boundary portion between the cam 60 and the operation lever 62. The step portions 64a, 64b are arranged on both sides of the shaft hole of the cam 60 corresponding to the pin tip portions 63a, 63b protruding from both sides of the shaft 59.

When the cam 60 is biased toward the pin by the compression coil spring 61, the two pin tips 63a and 63b come into contact with the stepped portions 64a and 64b and engage with each other. 60 cannot be rotated about the shaft 59. On the contrary, when the cam 60 slides on the shaft 59 against the compression coil spring 61 and the engagement is released, the cam 60 can rotate around the shaft 59.

The second engaging portion 65 is formed as step portions 65a and 65b on both sides of a groove provided between the two step portions 64a and 64b. Then, after the engagement is released and the cam 60 rotates about the shaft 59 by 90 ° from the above position, the compression coil spring 61 urges the cam 60 toward the pin tips 63a and 63b. Then, the tip end of one pin enters the groove and engages with the stepped portions 65a and 65b, so that the cam 60 cannot rotate about the shaft 59.

Next, a series of operations of the nail driving machine of the above-described embodiment will be described separately for each mode of continuous hammering and single shot hammering. In the case of continuous striking, as shown in FIGS. 1 and 2, the operation lever 62 is rotated downward. Since the engaging piece 56c of the contact arm 56 abuts on the flat portion 60a of the cam 60, the contact arm 56 has its rear end portion 56b in the vicinity of the pin 52 of the trigger 51 as shown in FIG. Stop to come.

In the state of FIG. 5, the contact lever 53 is merely in contact with the stem 44 of the trigger valve 38, and the nailing machine does not operate. Further, as shown in FIG. 6, simply pulling the trigger 51 does not operate the nail driver.

In the state shown in FIGS. 5 and 6, since the piston portion 46 of the stem 44 is at the top dead center, the compressed air in the air chamber 29 passes through the air supply hole 43, the air supply / exhaust hole 42 and the vent hole 37, and the valve chamber 36. (Fig. 1), the sliding valve 31 is pushed toward the cylinder 19 side. Therefore, the cylinder 19 is closed, and the piston 23 and the driver 22 remain stationary.

When nailing, the front end portion 56a of the contact arm 56 may be pressed against the work surface while the trigger 51 of FIG. 6 is pulled. As a result, the contact arm 56 slides backward as a whole on the nailing machine, and the rear end portion 56b rotates the contact lever 53 backward, as shown in FIG. The stem 44 is retracted by the rotation of the contact lever 53 to connect the air supply / exhaust hole 42 to the exhaust hole 40. Therefore, the compressed air in the valve chamber 36 (FIG. 1) is discharged, and the slide valve 31 is compressed by the compressed air in the air chamber 29 on the front edge of the slide valve 31 against the compression coil spring 35. It moves to the middle right to open the rear end of the cylinder 19 and shuts off the inside of the cylinder 19 and the atmosphere. The compressed air in the air chamber 29 enters the cylinder 19 from the rear end of the cylinder 19 and pushes the piston 23 leftward. Therefore, the driver 22 advances in the guide cylinder 54 and drives the nail toward the work surface.

When the contact arm 56 is separated from the work surface after the nail is driven, the contact arm 56 is moved to the position where the engaging piece 56 c of the contact arm 56 comes into contact with the flat portion 60 a of the cam 60 by the action of the compression coil spring 58. Upon return, the stem 44 also returns to the state shown in FIG. Accordingly, the sliding valve 31 closes the cylinder 19 by receiving the force of the compressed air, cuts off the supply of the compressed air into the cylinder 19, and causes the inside of the cylinder 19 to communicate with the atmosphere. The piston 23 in the cylinder 19 is moved to the right by the compressed air in the return air chamber 28 and returns to its original position.

When the trigger 51 is released while the contact arm 56 is pressed against the work surface, the stem 44 returns to the intermediate position as shown in FIG. 8, but the supply hole 43 and the supply / exhaust hole 42 are separated from each other. Since the O-ring 49 is still closed during that time, the inside of the valve chamber 36 of the sliding valve 31 is kept under atmospheric pressure, and the sliding valve 31 puts the cylinder 19 in the released state. Therefore, the compressed air from the air chamber 29 causes the piston 23 to remain stopped at the left end. After that, when the contact arm 56 is separated from the work surface, the state similar to that of FIG. 5 is restored, and the piston 23 returns to the original position.

The next nail driving can be performed immediately by simply pressing the contact arm 56 against the work surface while pulling the trigger 51. In the case of a single shot, the operating lever 62 is operated to change the state of FIG. 1 to the state of FIG. In operating the operation lever 62, first, in FIG. 2, the operation lever 62 is pressed against the compression coil spring 61 to release the engagement between the first engaging portions 64a, 64b and the protrusions 63a, 63b. . Next, the operation lever 62 is rotated upward by 90 °. As a result, the cam 60 retracts the engagement piece 56c of the contact arm 56 at the flat portion 60b. When the pressure is released, the second engaging portions 65a and 65b engage with the protrusions 63a and 63b to maintain the current posture of the cam 60. As shown in FIG. 9, the contact arm 56 stops at the position where the rear end portion 56 b thereof projects slightly rearward from the pin 52 of the trigger 51.

As a result, the conversion to the single shot driving mode is completed. Under this mode, when the front end portion 56a of the contact arm 56 is pressed against the work surface and the trigger 51 is pulled, the contact lever 53 causes the trigger 51 to move. And the stem 44 of the trigger valve 38 are pushed backward. As a result, the same state as in FIG. 7 is established, the air chamber 29 and the cylinder 19 are brought into conduction, and the driver 22 is moved forward by the compressed air to drive the nail out of the guide cylinder 54 toward the work surface.

After that, as shown in FIG. 10, even if the contact arm 56 is separated from the work surface while the trigger 51 is pulled, the contact lever 53 is supported by the rear end portion 56b of the contact arm 56 and the stem 44 is still kept. Since the driver is pushing, the driver 22 keeps the forward movement state. That is, since the valve chamber 36 is under atmospheric pressure and the slide valve 31 keeps the cylinder 19 open, the piston 23 maintains the state in which it is moved to the left end by the compressed air.

When the trigger 51 is released, the stem 44 of the trigger valve 38 is released and the spring 45 in the trigger valve 38 returns it to its original position. As a result, the ventilation passage 37 communicates with the air supply hole 43 via the air supply / exhaust hole 42, and the slide valve 31 closes the cylinder 19. The cylinder 19 is stopped from being supplied with the compressed air from the air chamber 29, and is pushed backward by the compressed air from the return air chamber 28 to return to the original position.

When the contact arm 56 is pressed against the work surface and the trigger 51 is pulled during nailing, the contact arm 56 and the stem 44 may move to the left due to vibration or recoil during nailing. is there. However, even in such a case, the contact arm 56 is blocked by the flat portion 60b of the cam 60 and does not move further to the left than the position in FIG. 10, so the contact lever 53 stops the stem 44 at the intermediate position in FIG. Let Therefore, the air supply hole 43 and the air supply / exhaust hole 42 are still shut off by the O-ring 49, the inside of the valve chamber 36 of the slide valve 31 is kept at atmospheric pressure, and the slide valve 31 releases the cylinder 19. Put. Then, due to the compressed air from the air chamber 29, the piston 23 remains stopped at the left end. This will prevent double strikes. After that, when the contact arm 56 is separated from the work surface and the trigger 51 is released, the trigger valve 38 returns to the same state as in FIG. 5, and the piston 23 returns to the original position.

The next nail driving can be performed by pulling the trigger 51 and pressing the contact arm 56 against the work surface.

[0052]

[Effect of the device]

 Since the present invention is configured as described above, the operation of pushing or rotating the cam along the axis is required when changing modes. Therefore, there is an effect that the cam is prevented from moving due to an impact at the time of nailing, and the set mode can be reliably maintained.

[Brief description of drawings]

FIG. 1 is a partial cutaway vertical sectional view of a nailing machine having an operation mode switching device according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a perspective view of a cam of a switching operation unit and its surroundings.

FIG. 5 is a partial cutaway vertical sectional view of a trigger and a peripheral portion of the trigger valve when not nailing in a continuous driving mode.

FIG. 6 is a partially cutaway vertical sectional view when a trigger is pulled in the state of FIG.

FIG. 7 is a partial cutaway vertical sectional view in the case where the contact arm is further pushed from the state of FIG. 6 to perform nailing.

8 is a partial cutaway vertical cross-sectional view when only the trigger is returned from the state of FIG.

FIG. 9 is a partial cutaway vertical sectional view of a trigger and a peripheral portion of a trigger valve when not nailing in a single shot mode.

FIG. 10 is a partial cutaway vertical cross-sectional view when only a trigger is pulled in the state of FIG.

FIG. 11 is a partially cutaway vertical sectional view of a nailing machine provided with a conventional operation mode switching device.

[Explanation of symbols]

 38 ... Trigger valve 44 ... Stem 53 ... Contact lever 56 ... Contact arm 57 ... Switching operation part 59 ... Shaft 60 ... Cam 61 ... Elastic member 62 ... Operation lever 63 ... Protrusion 64 ... First engaging part 65 ... Second Engagement part

Claims (1)

[Scope of utility model registration request] 1. A contact arm for converting a turning stroke of a contact lever, which comes into contact with a stem of a trigger valve of a nailing machine, into either a continuous striking or a single-shot striking; A switching operation section arranged in front of a trigger of the nail driving machine for switching between two sliding strokes corresponding to the rotation stroke of the nailing machine. Is a cam loosely fitted to a shaft of the nailing machine main body side that abuts on an intermediate portion of the contact arm and switches the contact arm between the two types of sliding strokes, and the cam in the central axis direction of the shaft. An elastic member for biasing, an operating lever connected to the cam, and the cam on the shaft fixed to the side biased by the elastic member. Protrusions, and first and second provided on the cam that selectively engages with the protrusion in accordance with a sliding operation and a rotating operation of the cam along the axis when switching the sliding stroke. The operation mode switching device for a nailing machine is characterized in that