Driving tool

A driving tool includes a tool body, a flywheel, a driver, a pressing mechanism and a solenoid. The solenoid has an actuation part configured to linearly move in a specified direction from an initial position when the solenoid is activated. The pressing mechanism includes a holder turnably supported around a rotation axis relative to the tool body, and a roller rotatably supported by the holder. The holder is turnable between a first position in which the roller is apart from the driver and a second position in which the roller abuts on the driver and presses the driver toward the flywheel to thereby enable transmission of the rotational energy to the driver. The actuation part is configured to turn the holder from the first position to the second position while moving from the initial position.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Japanese patent application No. 2019-112272 filed on Jun. 17, 2019, contents of which are fully incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a driving tool which is configured to drive a fastener into a workpiece with a driver.

BACKGROUND ART

A driving tool is known which is configured to strike a fastener such as a nail and drive the fastener into a workpiece by linearly moving a driver. For example, in a driving tool disclosed in Japanese Unexamined Patent Application Publication No. 2018-12187, a lever is actuated by a solenoid to push the driver forward from an initial position. When the driver reaches a transmitting position located forward of the initial position, the driver is pushed out forward at high speed by rotational energy transmitted from a flywheel, and drives out a nail from a nose part.

SUMMARY

The present disclosure herein provides a driving tool which is configured to drive a fastener into a workpiece. The driving tool includes a tool body, a flywheel, a driver, a pressing mechanism and a solenoid.

The flywheel is housed in the tool body. The driver is disposed to face an outer periphery of the flywheel. The driver is configured to linearly move forward from an initial position along a moving axis by rotational energy transmitted from the flywheel, thereby striking and driving the fastener into the workpiece. The moving axis of the driver defines a front-rear direction of the driving tool. The pressing mechanism is disposed on a side opposite to the flywheel across the driver in a facing direction in which the flywheel and the driver face each other. The solenoid has an actuation part. The actuation part is configured to linearly move in a specified direction from an initial position when the solenoid is activated.

The pressing mechanism includes a holder and a roller. The holder is turnably supported around a rotation axis relative to the tool body. The roller is rotatably supported by the holder. The holder is turnable between a first position and a second position. The first position of the holder is a position in which the roller is apart from the driver. The second position of the holder is a position in which the roller abuts on the driver and presses the driver toward the flywheel to thereby enable transmission of the rotational energy to the driver. The actuation part is configured to move the holder from the first position to the second position while moving from the initial position.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An embodiment is now described with reference to the drawings. In the present embodiment, a nailing machine1is described as an example of a driving tool. The nailing machine1is a tool which is capable of performing a nailing operation of driving a nail101into a workpiece (such as wood) by linearly driving out the nail101from an outlet120.

First, the general structure of the nailing machine1is described with reference toFIG. 1. As shown inFIG. 1, an outer shell of the nailing machine1of the present embodiment is mainly formed by a tool body11, a handle17and a magazine19.

The tool body11includes a body housing12and a nose part14.

The body housing12houses a motor2, a driver-driving mechanism4including a flywheel5, a driver3, and a return mechanism (not shown). The flywheel5is configured to be rotationally driven by the motor2to store rotational energy. The driver3is disposed to face an outer periphery of the flywheel5, and configured to linearly move along a moving axis A1by rotational energy transmitted from the flywheel5, and drive a nail101into a workpiece. The return mechanism is configured to return the driver3to an initial position after the nail101is driven out.

The nose part14is connected to one end of the body housing12in an extending direction of the moving axis A1(hereinafter simply referred to as a moving-axis-A1direction). The nose part14has a driver passage (not shown) which extends through the nose part14in the moving-axis-A1direction. One end of the driver passage is open to the inside of the body housing12. The other end of the driver passage is open to the outside of the nailing machine1to form an outlet120, through which the nail101may be driven out. A contact arm125is held on the nose part14, adjacent to the outlet120. The contact arm125is movable in the moving-axis-A1direction. Further, a switch (not shown) is disposed within the body housing12. The switch is configured to be normally kept in an OFF state, and to be switched to an ON state when the contact arm125is pressed.

The handle17is connected to a central portion of the body housing12in the moving-axis-A1direction, and extends in a direction crossing the moving axis A1. The handle17is a portion to be held by a user. A trigger171is provided in a base end portion (an end portion connected to the body housing12) of the handle17and configured to be depressed by a user. A switch172is disposed within the handle17. The switch172is configured to be normally kept in an OFF state, and to be switched to an ON state when the trigger171is depressed. Further, a battery-mounting part175having terminals is provided on a distal end portion (an end portion opposite to the base end portion) of the handle17. A rechargeable battery100is removably mounted to the battery-mounting part175. Further, a controller18for controlling operation of the nailing machine1is disposed inside the distal end portion of the handle17.

The magazine19is configured to be loaded with a plurality of nails101and mounted to the nose part14. The nails101loaded in the magazine19are fed one by one to the driver passage by a nail-feeding mechanism (not shown). The structure of the magazine19is well known and therefore its description is omitted.

The detailed structure of the nailing machine1is now described. In the following description, for convenience sake, the moving-axis-A1direction of the driver3(a left-right direction as viewed inFIG. 1) is defined as a front-rear direction of the nailing machine1. In the front-rear direction, the outlet120side (a left side as viewed inFIG. 1) of the tool body11is defined as a front side of the nailing machine1, while its opposite side (a right side as viewed inFIG. 1) is defined as a rear side. Further, a direction (an up-down direction as viewed inFIG. 1) which is orthogonal to the moving axis A1and which corresponds to the extending direction of the handle17is defined as an up-down direction of the nailing machine1. In the up-down direction, the side (an upper side as viewed inFIG. 1) on which the handle17is connected to the tool body11(the body housing12) is defined as an upper side, while the side (a lower side as viewed inFIG. 1) of the distal end portion (the end portion on which the battery100is mounted) of the handle17is defined as a lower side. Further, a direction which is orthogonal to the front-rear direction and the up-down direction is defined as a left-right direction.

First, the motor2is described. As shown inFIG. 1, the motor2is housed in a rear lower portion of the body housing12. Further, the motor2is arranged such that a rotation axis of an output shaft (not shown) extends in the left-right direction, orthogonal to the moving axis A1. In the present embodiment, a brushless DC motor is used as the motor2. A pulley21is connected to the output shaft of the motor2and rotates together with the output shat. In the present embodiment, when the contact arm125of the nose part14is pressed against a workpiece and the switch of the contact arm125is turned on, or when the trigger171is depressed and the switch172is turned on, the controller18controls to supply current from the battery100to the motor2to start driving of the motor2.

The driver3is now described. As shown inFIGS. 1 and 2, the driver3is an elongate member and is arranged such that its longitudinal axis extends along the moving axis A1. The driver3has a bilaterally symmetrical shape, and includes a body30, a striking part34and a pair of arms35. The body30has a generally rectangular plate-like shape as a whole. The striking part34extends forward from a front end of the body30and has a smaller width than the body30in the left-right direction. The arms35protrude to the left and right from a rear portion of the body30.

The body30is provided with a pair of roller-abutting parts31protruding upward from an upper surface of the body30and extending substantially in the front-rear direction along left and right edges of the body30. The roller-abutting parts31are portions to be pressed by a roller63. The roller-abutting part31is configured to have a thickness in the up-down direction (a height in the up-down direction from the upper surface of the body30to a protruding end surface (an upper surface of the protruding end)) which is not constant but changes toward the rear. More specifically, a front end portion of the roller-abutting part31is configured to have a thickness gradually increasing toward the rear at a certain ratio. In other words, an upper surface of the front end portion of the roller-abutting part31is a flat surface which extends obliquely upward toward the rear. The front end portion of the roller-abutting part31having such a thickness is hereinafter referred to as a cam part32. A portion of the roller-abutting part31which extends rearward of the cam part32has a substantially constant thickness, and is hereinafter referred to as a straight part33.

The driver3is held to be movable between an initial position and a nail-driving position along the moving axis A1(that is, in the front-rear direction of the nailing machine1or in the longitudinal direction of the driver3). The initial position is a position where the driver3is held in a state in which the driver-driving mechanism4is not operating (hereinafter referred to as an initial state). In the present embodiment, as shown inFIG. 1, the initial position of the driver3is set to a position where a rear end of the driver3abuts on a stopper121, which is provided in a rear end portion of the body housing12. The nail-driving position is a position where the driver3drives the nail101into a workpiece after being moved forward by the driver-driving mechanism4. In the present embodiment, as shown inFIG. 3, the nail-driving position of the driver3is set to a position where a front end of the driver3slightly protrudes from the outlet120. The nail-driving position is also a position where front ends of the pair of arms35abut from the rear on a pair of stoppers123, which are provided within a front end portion of the body housing12. With the above-described arrangement, in the present embodiment, the initial position and the nail-driving position can also be respectively referred to as a rearmost position and a foremost position in a movable range of the driver3.

Although not described nor shown in detail, the arms35are connected to the return mechanism by connecting members. The return mechanism is configured to return the driver3to the initial position after the driver3is moved forward from the initial position. In the nailing machine1of the present embodiment, any known structure may be adopted as the return mechanism. For example, the return mechanism may be configured to return the driver3to the initial position via the connecting members along the moving axis A1by an elastic force of a spring member (such as a compression coil spring and a torsion coil spring) after the driver3is moved forward from the initial position.

The driver-driving mechanism4is now described. In the present embodiment, as shown inFIG. 1, the driver-driving mechanism4includes a flywheel5, a pressing mechanism6and a solenoid8. The structures of these components are now described in detail in this order.

Firstly, the flywheel5is described. As shown inFIG. 1, the flywheel5has a cylindrical shape, and is rotatably supported in front of the motor2within the body housing12. The flywheel5is configured to be rotationally driven by the motor2. A rotation axis of the flywheel5extends in parallel to a rotation axis of the motor2and in a direction (the left-right direction) which is orthogonal to the moving axis A1of the driver3. A pulley51is connected to a support shaft of the flywheel5. The pulley51rotates together with the support shaft and the flywheel5. A belt25is looped over the pulleys21and51. When the motor2is driven, rotation of the output shaft of the motor2is transmitted to the flywheel5via the belt25, and the flywheel5rotates counterclockwise as viewed inFIG. 1.

The pressing mechanism6is now described. As shown inFIG. 1, the pressing mechanism6is disposed on the side opposite to the flywheel5across the driver3in a facing direction (the up-down direction) in which the flywheel5and the driver3face each other. Specifically, the pressing mechanism6is disposed to face the driver3from above. The pressing mechanism6is configured to press the driver3located in the initial position, downward against the flywheel5, to thereby enable transmission of the rotational energy from the flywheel5to the driver3. As shown inFIG. 4, in the present embodiment, the pressing mechanism6includes a pressing unit60and a biasing spring69.

The pressing unit60is now described. As shown inFIGS. 4 and 5, the pressing unit60includes a holder base61, a roller holder62, a roller63, a biasing spring64and a fastening member65.

The holder base61is a member which is turnably supported by the body housing12, and configured to hold the roller holder62such that the roller holder62is movable relative to the holder base61. Specifically, as shown inFIGS. 5 and 6, the holder base61is generally home-base shaped as a whole when viewed from above. The holder base61is arranged such that a protruding corner portion of the home-base shaped holder base61is located at the rear end. A pair of circular columnar shafts611are protruding to the left and right on a front end portion of the holder base61. The shafts611are coaxially arranged on an axis extending in the left-right direction. The rear end portion (the protruding corner portion) of the holder base61is inclined obliquely downward toward the rear when viewed from the right or left. This portion forms a press-receiving part613to be pressed by a plunger83. Further, a threaded hole615is formed in the center of the holder base61, and a pair of through holes616are formed on opposite sides of the threaded hole615.

The roller holder62is a member which is configured to rotatably support the roller63. The roller holder62is held by the holder base61so as to be movable generally in the up-down direction relative to the holder base61. Specifically, as shown inFIG. 5, the roller holder62includes an annular spring-receiving part621and a pair of left and right legs625protruding downward from the spring-receiving part621. The roller holder62is engaged with the holder base61with the spring-receiving part621disposed on an upper side of the holder base61and with the legs625inserted through the through holes616(seeFIG. 6).

The roller63is rotatably supported by the roller holder62via a shaft626which is supported by lower end portions of the legs625. A rotation axis of the roller63extends in the left-right direction. The length of the roller63in the left-right direction is set to be longer than the distance between the pair of roller-abutting parts31(seeFIG. 2) of the driver3in the left-right direction. The roller63can thus abut on both of the roller-abutting parts31.

The biasing spring64is disposed on an upper side of the spring-receiving part621of the roller holder62. In the present embodiment, a disc spring is used for the biasing spring64. The biasing spring64has an inner diameter substantially equal to the inner diameter of the spring-receiving part621, and an outer diameter slightly smaller than the outer diameter of the spring-receiving part621. Further, the biasing spring64has a nonlinear characteristic. Specifically, an amount of displacement of the biasing spring64is not proportional to a load (an elastic force, a spring force, a biasing force) of the biasing spring64. More specifically, the biasing spring (disc spring)64has a nonlinear characteristic that a rate of increase of a load relative to increase of the amount of displacement decreases as the amount of displacement increases.

The fastening member65has a diameter substantially equal to the inner diameter of the spring-receiving part621of the roller holder62and the biasing spring64. A flange part651protrudes radially outward from an upper end portion of the fastening member65. A male thread part653protrudes downward from the center of a lower end portion of the fastening member65. The fastening member65is inserted through the biasing spring64and the spring-receiving part621with the flange part651placed on the biasing spring64, and the male thread part653is threadedly engaged with the thread hole615of the holder base61. Thus, the fastening member65is fixed to the holder base61with the roller holder62and the biasing spring64therebetween, so that the pressing unit60is formed into a single assembly.

In the present embodiment, the biasing spring64is disposed between the spring-receiving part621of the roller holder62and the flange part651of the fastening member65in a slightly compressed state. Thus, the roller holder62is biased downward relative to the holder base61. Therefore, in a state (initial state) in which an external force of pushing the roller holder62upward via the roller63is not applied thereto, the roller holder62is held with a lower surface of the spring-receiving part621abutted on an upper surface of the holder base61. On the other hand, when the roller holder62is pushed upward via the roller63, the roller holder62and the roller63move upward relative to the holder base61while compressing the biasing spring64.

The pressing unit61having the above-described structure is turnably supported relative to the body housing12via a pair of support blocks71. A support structure of supporting the pressing unit61is now described.

As shown inFIGS. 7 to 9, a pair of left and right support walls13are provided within the body housing12(seeFIG. 1). The support walls13are plate-like portions arranged opposite to each other in the left-right direction and integrally connected and fixed to the body housing12. Each of the support walls13has a guide groove130. The guide groove130is a through hole extending through the support wall13in the left-right direction. The guide groove130includes a first portion131and a second portion132. The first portion131has a generally rectangular shape in a side view and extends in the up-down direction. The second portion132has a circular arc shape in a side view and extends continuously from an upper end portion of the first portion131. The second portion132extends obliquely upward and rearward from the same position as the position of the first portion131in the front-rear direction.

Each of the support blocks71is a generally rectangular parallelepiped member. The support block71is fitted in the first portion131of the guide groove130. The support block71has a through hole extending in the left-right direction. The left and right shafts611of the holder base61are rotatably inserted through the through holes of the pair of left and right support blocks71, respectively. Thus, the pressing unit60is supported by the support walls13(and thus the body housing12) via the support blocks71so as to be rotatable around a rotation axis R1extending in the left-right direction. Further, an upper rear end portion of the support block71has an inclined surface inclined downward toward the rear.

As shown inFIG. 4, the biasing spring69is configured to bias the pressing unit60(specifically, the holder base61). The biasing member69is disposed under the holder base61in the vicinity of the press-receiving part613. In the present embodiment, the biasing spring69is a compression coil spring and is arranged to extend in the up-down direction. A lower end of the biasing spring69is held in abutment with a spring-receiving part134which is fixed to the support walls13(seeFIG. 7), and an upper end of the biasing spring69is held in abutment with a lower surface of the holder base61. The plunger83of the solenoid8is always held in abutment with an upper surface (inclined surface) of the press-receiving part613of the holder base61and restricts upward movement of the press-receiving part613, which will be described in detail later. Thus, the biasing spring69is always compressed to bias the pressing unit60(the holder base61) in such a direction that the rear end portion (the press-receiving part613) of the pressing unit60is moved upward around the rotation axis R1provided in the front end portion of the pressing unit60(in the counterclockwise direction as viewed from the left or the direction of an arrow inFIG. 4).

Further, in the present embodiment, as shown inFIG. 7, the pressing unit60is also supported to be movable in the up-down direction relative to the body housing12via the support blocks71. More specifically, each of the support blocks71is configured to be slidable in the up-down direction within the guide groove130, so that the pressing unit60is also movable in the up-down direction along with the movement of the support blocks71in the up-down direction. Each of the support blocks71is normally held in a specified position by a locking block73which is fitted in the guide groove130, while being allowed to move upward when the locking block73is moved, which is described in detail below.

As shown inFIGS. 7 to 9, the locking block73is a generally rectangular parallelepiped member. The locking block73has an arcuately curved lower end surface and a through hole extending in the left-right direction. The locking block73is configured to move in an arc between a lower front end portion and an upper rear end portion of the second portion132of the guide groove130according to an operation of a lever75by a user.

The lever75has a generally U-shaped operation part751. Both end portions of the operation part751are respectively supported by the left and right support walls13via support pins752so as to be rotatable around a rotation axis R2extending in the left-right direction. A pair of arms754respectively protrude from the both end portions of the operation part751. A distal end portion of each arm754protrudes toward the inside of the support wall13and rotatably inserted into the through hole of the locking block73.

As shown in a solid line inFIG. 7, when the lever75is turned rearward (in the clockwise direction as viewed from the left or the direction of arrow CW inFIG. 7) to a position where the operation part751is closest to an upper end of the support wall13, each of the arms754extends generally downward, and the locking block73connected to the distal end portion of the arm754is located within the lower front end portion of the second portion132. At this time, the lower end surface of the locking block73abuts on an upper end surface of the support block71, thus preventing the support block71from moving upward from a lowermost position within the first portion131. Thus, the support block71is locked in the lowermost position by the locking block73. Therefore, respective positions of the lever75and the locking block73when the operation part751is located closest to the upper end of the support wall13are hereinafter also referred to as lock positions. During the nailing operation of the nailing machine1, the lever75and the locking blocks73are located in their respective lock positions and the support blocks71are located in their lowermost positions. The lowermost position of the support block71is hereinafter also referred to as a normal position.

As shown in a dotted line inFIG. 7, when the lever75is turned from the lock position in such a direction that the operation part751is moved upward away from the support wall13(in the counterclockwise direction as viewed from the left or the direction of arrow CCW inFIG. 7), each of the locking blocks73moves upward and rearward within the second portion132, from the lock position in the lower front end portion of the second portion132. Thus, the lock by the locking blocks73is released, so that the support blocks71are allowed to move upward from their normal positions (lowermost positions). Therefore, respective positions of the lever75and the locking block73when the operation part751is in an uppermost position and the locking block73is located within the upper rear end portion of the second portion132are hereinafter also referred to as unlock positions. The lever75and the locking blocks73can be moved to their respective unlock positions, for example, when a trouble such as jamming of the driver3occurs, which will be described in detail later.

The solenoid8is now described with reference toFIG. 4. The solenoid8is a well-known electric component which is configured to convert electrical energy into mechanical energy of linear motion by utilizing an electric field generated by energization of a coil81of the solenoid8. The solenoid8may also be referred to as a solenoid actuator or a linear solenoid. In the present embodiment, the solenoid8is used to turn the holder base61against the biasing force of the biasing spring69when activated.

As shown inFIG. 4, the solenoid8includes the coil81housed within a cylindrical case (not shown), the plunger83which is linearly movable in an axial direction of the coil81, and a return spring85. The solenoid8is supported by the support walls13(seeFIG. 7) such that a moving axis A2of the plunger83extends in parallel to the moving axis A1of the driver3(that is, in the front-rear direction).

The plunger83includes a rod part831and a turnable part833. The rod part831is a rod-like portion protruding forward from the coil81along the moving axis A2. The turnable part833is connected to a front end portion of the rod part831via a connecting pin so as to be turnable around a rotation axis R3extending in the left-right direction. The turnable part833has a generally rectangular parallelepiped shape, but a lower surface of a front end portion of the turnable part833forms an inclined surface834which is inclined upward toward the front. The inclined surface834is at least partially held in abutment with the upper surface (inclined surface) of the press-receiving part613of the holder base61. Further, an upper guide136and a lower guide137are disposed in front of the coil81and respectively on upper and lower sides of the turnable part833, and fixed to the support walls13. A passage138for guiding movement of the turnable part833is formed between the upper guide136and the lower guide137and extends linearly in the front-rear direction. The height of the passage138in the up-down direction is set to be slightly larger than the height of the turnable part833. Further, a front end of the upper guide136is located forward of a front end of the lower guide137in the front-rear direction.

The return spring85is disposed between a rear end surface of the case of the coil81and a flange part formed on a rear end of the plunger83. The return spring85always biases the plunger83rearward relative to the coil81. In the present embodiment, a conical coil spring is used for the return spring85.

With the above-described structure, in an OFF state in which the solenoid8is not activated (that is, when the coil81is not energized), the plunger83is held in a rearmost position within its movable range (hereinafter also referred to as an initial position) by the biasing force of the return spring85. As shown inFIG. 4, when the plunger83is located in the rearmost position, a front end of the turnable part833is located rearward of the front end of the upper guide136, and a rear end of the turnable part833is located generally at the same position as rear ends of the upper guide136and the lower guide137. Thus, generally the whole of the turnable part833is located within the passage138. Further, the inclined surface834of the front end portion of the turnable part833abuts on an upper surface of the press-receiving part613of the holder base51, and locks the holder base61which is biased to turn by the biasing spring69. At this time, the press-receiving part613is located in an uppermost position within its movable range.

When the solenoid8is activated and switched to an ON state (that is, when the coil81is energized), as shown inFIG. 10, the plunger83moves forward from the rearmost position against the biasing force of the return spring85. Along with the forward movement of the plunger83, the turnable part833presses the press-receiving part613downward via the inclined surface834while moving forward. Therefore, the holder base61turns against the biasing force of the biasing spring69in such a direction that the press-receiving part613moves downward (in the clockwise direction as viewed from the left or the direction of an arrow inFIG. 10). Thus, when the solenoid8is switched from the OFF state to the ON state, the plunger553moves forward from the rearmost position (initial position), pushes the press-receiving part613downward from the uppermost position and thereby turns the holder base61.

Operation of the nailing machine1during a nailing operation is now described.

As described above, a nailing operation is performed with the lever75and the locking blocks73located in their lock positions and with the support blocks71held in their normal positions as shown inFIG. 7. As shown inFIGS. 1 and 4, when the driver-driving mechanism4is in the initial state, the driver3is located in the initial position (rearmost position). The plunger83is in its initial position (rearmost position) and the holder base61is held with the press-receiving part613located in the uppermost position. At this time, the lower end of the roller63is located at a distance D1apart upward from an uppermost end of the roller-abutting parts31of the driver3. In other words, the roller63is held in a position apart from the driver3(where the roller63cannot come into contact with the driver3). A position of the holder base61in the initial state (that is, when the support blocks71are in the normal positions and the press-receiving part613is located in the uppermost position) is hereinafter referred to as a separate position. In the initial state, the roller63is located right above the cam parts32of the roller-abutting parts31and faces an upper surfaces of the cam parts32.

When the switch (not shown) of the contact arm125or the switch172of the trigger171is switched to the ON state, the controller18controls to supply current from the battery100to the motor2to start driving of the motor2. At this time, the flywheel5also starts rotating. In this stage, however, the flywheel5is not in contact with the driver3, so that the rotational energy of the flywheel5is not transmitted to the driver3. Therefore, even if the flywheel5rotates, the driver3does not move.

Thereafter, when the switch (not shown) of the contact arm125and the switch172of the trigger171are both placed in the ON state, the controller18activates the solenoid8by energizing the coil81. Then, as shown inFIG. 10, the plunger83moves forward from the initial position and turns the holder base61. Along with this movement, the roller63moves downward and pushes the driver3downward in abutment with the upper surfaces of the cam parts32. The roller63then presses the driver3against the flywheel5to cause the driver3to be frictionally engaged with the flywheel5. Here, the “frictionally engaged” state refers to a state (including a sliding state) that the two members are engaged with each other by frictional force. The frictional engagement between the driver3and the flywheel5enables transmission of the rotational energy from the flywheel5to the driver3. The driver3receives the rotational energy from the flywheel5and starts moving forward at high speed.

A position of the holder base61when the support blocks71are in the normal positions and the roller63presses the driver3to frictionally engage the driver3with the flywheel5(to enable transmission of the rotational energy) is hereinafter referred to as a pressing position. Further, a position of the plunger83at this time is referred to as an actuation position. When the holder base61is located in the pressing position, the distance between the rotation axis R1and a contact position (point P1inFIG. 10) between the roller63and the driver3is shorter than the distance between the rotation axis R1and a contact position (point P2inFIG. 10) between the turnable part833and the press-receiving part613. With this structure, when the roller63presses the driver3, the force of pressing back the plunger83toward the initial position can be made relatively small.

As the driver3moves forward, the cam parts32, which have the thickness gradually increasing toward the rear, push the roller63and the roller holder62upward relative to the holder base61. Thus, the biasing spring64is compressed and displaced, so that its elastic force is increased. Therefore, the roller63biased by the biasing spring64strongly presses the driver3against the flywheel5, so that the frictional engagement between the driver3and the flywheel5gets firmer. As shown inFIG. 11, when the roller63passes a rear end of the cam parts32and reaches the straight parts33, the roller63and the roller holder62are pushed up by a distance D2from the position where the roller63abuts on the cam parts32and frictionally engages the driver3with the flywheel5. The load of the biasing spring64reaches an upper limit and is kept constant. The driver3moves forward while being strongly pressed against the flywheel5by the roller63, and strikes the nail101.FIG. 11shows a state in which the driver3is located in a striking position where the driver3strikes the nail101(seeFIG. 1) with a tip of the striking part34.

In the present embodiment, as described above, the biasing spring64has a nonlinear characteristic that the rate of increase of the load relative to increase of the amount of displacement decreases as the amount of displacement increases. Therefore, in the process that the roller63moves rearward relative to the cam parts32along with the movement of the driver3, the rate of increase of the load of the biasing spring64varies. Specifically, the load of the biasing spring64rapidly increases immediately after the driver3is pressed against the flywheel5and frictionally engaged therewith and the roller63starts moving on the cam parts32, while it gently increases as the roller63approaches the rear ends of the cam parts23. Utilizing the biasing spring64having such a characteristic can establish firm frictional engagement between the driver3and the flywheel5immediately after the driver3starts moving, and can gently shift to a state in which the load of the biasing spring64is maximum.

Then, the driver3further moves to the nail-driving position shown inFIG. 3and drives the nail101into the workpiece. The driver3stops moving when the front ends of the arms35of the driver3abut on the stoppers123from the rear. When the driver3reaches the nail-driving position, the roller63and the roller holder62are no longer pushed up by the roller-abutting parts31. Therefore, the roller holder62biased by the biasing spring64moves downward relative to the holder base61as shown by an arrow inFIG. 12, and returns to the position where the lower surface of the spring-receiving part621abuts on the upper surface of the holder base61.

As shown inFIG. 13, when the solenoid8is activated and the holder base61is placed in the pressing position, the front end of the turnable part833is located forward of the front end of the upper guide136(that is, located outside the passage138), and the rear end of the turnable part833is located rearward of the front end of the lower guide137(that is, located inside the passage138). As described above, the holder base61is biased to turn around the rotation axis R1in the counterclockwise direction as viewed from the left. The turnable part833, which is held in abutment with the press-receiving part613, is subjected to this biasing force via the holder base61. This biasing force acts in a tangential direction of a circle around the rotation axis R1as viewed from the left (in the direction of an arrow inFIG. 13). Therefore, the turnable part833turns around the rotation axis R3in the clockwise direction as viewed from the left and held in a position where a lower rear end of the turnable part833abuts on the lower guide137and an upper surface of the turnable part833abuts on a lower front end of the upper guide136. An upper front end of the turnable part833is located forward and upward of an upper front end of the passage138. Therefore, when the plunger83attempts to move rearward, resistance is generated at a contact position (point P3inFIG. 13) between the turnable part833and the upper guide136and a contact position (point P4inFIG. 13) between the turnable part833and the lower guide137.

Thereafter, when the roller63is pushed up by the cam parts32along with the forward movement of the driver3, the biasing spring64is compressed and a further biasing force of the biasing spring64is applied to the holder base61in a direction to push the fastening member65upward. The turnable part833is subjected to this biasing force via the holder base61. In the present embodiment, the turnable part833is configured such that the biasing force of the return spring85for the plunger83exceeds the resistance of the turnable part833when the biasing force of the biasing spring64which is generated by the roller63being pushed upward is not applied to the holder base61, while the resistance of the turnable part833exceeds the biasing force of the return spring85when such biasing force of the biasing spring64is applied to the holder base61. In other words, the turnable part833is configured to prevent the plunger83from returning to the initial position while the roller63is pushed upward, even if the solenoid8is turned to the OFF state. Thus, the holder base61is also prevented from returning from the pressing position to the separate position.

In the present embodiment, the controller18is configured to stop energization of the coil81when a specified time elapses which is required for the driver3to reach the striking position after start of energization of the coil81. As described above, however, while the driver3moves from the striking position to the nail-driving position, the plunger83is held in the actuation position by the resistance of the turnable part833and holds the holder base61in the pressing position. Therefore, the possibility of defective nail driving can be reduced which might otherwise be caused by such a failure that it becomes impossible to press the driver3or the frictional engagement becomes unstable due to insufficient pressing of the driver3, before completing driving of the nail101. Further, the need to closely control the timing to stop energization of the coil81can be eliminated.

When the driver3reaches the striking position and the roller holder62returns to the lowermost position, the plunger83moves rearward from the actuation position toward the initial position by the biasing force of the return spring85, as shown by an arrow inFIG. 14. Further, when the plunger83returns to the initial position, as shown inFIG. 15, the pressing unit60biased by the biasing spring69returns to the separate position (where the lower end of the roller63is located apart upward from the uppermost end of the driver3). Therefore, the driver3can be returned to the initial position by the return mechanism without interfering with the roller63. It is noted that the driver3may rebound forward by impact of collision between the rear end of the driver3and the stopper121. Even in such a case, since the holder base61is back in the separate position, the driver3can be prevented from being pressed by the roller63and frictionally engaged with the flywheel5, and thus from unintentionally driving out a nail.

The driver3may be stopped (jammed) within the driver passage for some reason (for example, jamming of the nail101) in the moving process of the driver3from the initial position to the nail-driving position. For example, the driver3may be stopped when the roller63is located on the straight part33as shown inFIG. 16. In such a case, the return mechanism (not shown) cannot return the driver3to the initial position even if the motor2is stopped, since the roller63is biased by the compressed biasing spring64and strongly pressing the driver3against the flywheel5. Therefore, in the present embodiment, the pressing unit60can be moved in the up-down direction relative to the body housing12by an operation of the lever75by a user, as described above, in order to eliminate jamming. Operation of the pressing unit60by an operation of the lever75by a user is now described.

As described above, a nailing operation is performed with the lever75located in the lock position. At this time, as shown inFIG. 16, the support blocks71are locked in the lowermost positions (normal positions) by the corresponding locking blocks73. Further, as described above, the plunger83is held in the actuation position by the turnable part833. From this state, as shown inFIG. 17, a user may turn the lever75to the unlock position to release the lock of the support blocks71. As a result, as shown inFIG. 18, at the same time when the compressed biasing spring64is restored, the holder base61turns in the clockwise direction as viewed from the left (in the direction of an arrow inFIG. 18) around the contact position between the turnable part833and the press-receiving part613, and the support blocks71move upward. Thus, the pressing of the roller63against the driver3can be released, so that the return mechanism (not shown) is allowed to return the driver3to the initial position. Further, as described above, the plunger83can also be returned to the initial position by the biasing force of the return spring85. Although not shown, the holder base61biased by the biasing spring69turns to a position where the upper surface of the press-receiving part613abuts on the turnable part833.

Thereafter, when the user returns the lever75to the lock position, the locking blocks73push down the support blocks71while turning the holder base61, in the process of moving downward and forward within the second portion132. At this time, the curved lower end surface of the locking block73abuts on the inclined surface of the upper rear end portion of the support block71, thus smoothly pushing down the support block71. The pressing unit60returns to a state as shown inFIG. 4in which the support blocks71are located in their lowermost positions and the holder base61is in the separate position. The nailing machine1is thus back to a state in which it is capable of performing a nailing operation.

As described above, the nailing machine1of the present embodiment includes the tool body11, the flywheel5, the driver3, the pressing mechanism6and the solenoid8. The driver3is configured to linearly move forward from the initial position along the moving axis A1by rotational energy transmitted from the flywheel5to thereby strike and drive a nail101into the workpiece. The pressing mechanism6is disposed on the side opposite to the flywheel5across the driver3. The pressing mechanism6includes the holder base61which is turnably supported around the rotation axis R1relative to the tool body11, and the roller63which is rotatably supported by the holder base61via the roller holder62. The holder base61is turnable between the separate position where the roller63is apart from the driver3and the pressing position where the roller63abuts on the driver3and presses the driver3toward the flywheel5to thereby enable transmission of the rotational energy from the flywheel5to the driver3. The solenoid8has the plunger83which is configured to linearly move forward from the initial position when the solenoid8is activated. The plunger83is configured to move the holder base61from the separate position to the pressing position while moving forward from the initial position.

With such a structure, the solenoid8can turn the holder base61to cause the roller63supported by the holder base61to press the driver3, thereby enabling transmission of the rotational energy to the driver3. In a system in which a driver is pushed out by a lever forward along a moving axis to a position to enable transmission of rotational energy from a flywheel, it is relatively difficult to adjust the position of the driver. Compared with such a system, in the present embodiment, it is relatively easy to turn the holder base61to a position where the roller63reliably presses the driver3. Therefore, the nailing machine1can realize more reliable transmission of the rotational energy to the driver3. Further, the moving path of the driver3can be shortened compared with the above-described system, since the driver3never moves forward without receiving the rotational energy.

Further, in the nailing machine1, the holder base61can be turned by the solenoid8of a simple structure which realizes simple linear motion of the plunger83. Particularly, in the present embodiment, the solenoid8is disposed such that the moving axis A2of the plunger83extends in parallel to the moving axis A1of the driver3. Thus, the driver3and the solenoid8can be arranged compactly along the front-rear direction, and the width of the tool body11in the left-right direction can be made relatively small.

Further, in the present embodiment, the roller63is supported via the roller holder62so as to be movable upward relative to the holder base61located in the pressing position. The driver3includes the cam parts32each having a thickness in the up-down direction gradually increasing toward the rear. Further, the pressing mechanism6includes the biasing spring64which is configured to bias the roller63toward the driver3by the elastic force being increased while the roller63is moved upward along with the forward movement of the cam parts32. Therefore, the pressing force against the driver3can be increased along with the movement of the driver3, so that further reliable transmission of the rotational energy can be realized. Further, a disc spring is used for the biasing spring64, so that it is capable of generating a large load while requiring a relatively small space.

Further, in the present embodiment, the holder base61is supported by the tool body11(the support walls13) via the shafts611. The shafts611are movable away from the driver3relative to the tool body11(that is, upward). Therefore, when the driver3becomes impossible to move (or jammed) while the holder base61is in the pressing position, the pressing of the roller63against the driver3can be released by moving the shafts611, so that the driver3can be moved. Particularly, in the present embodiment, the shafts611can be moved by the biasing force of the biasing spring64according to an operation of turning the lever75by a user. Thus, the user can eliminate jamming by only a simple operation.

Correspondences between the features of the above-described embodiment and the features of the invention are as follows. However, the features of the above-described embodiment are mere examples and thus do not limit the features of the invention. The nailing machine1is an example of the “driving tool”. The nail101is an example of the “fastener”. The tool body11is an example embodiment that correspond to the “tool body”. The flywheel5is an example of the “flywheel”. The driver3is an example of the “driver”. The moving axis A1is an example of the “moving axis of the driver”. The pressing mechanism6is an examples of the “pressing mechanism”. The solenoid8and the plunger83are examples of the “solenoid” and the “actuation part”, respectively. The holder base61and the roller63are examples of the “holder” and the “roller”, respectively. The rotation axis R1is an example of the “rotation axis”. The separate position and the pressing position of the holder base61are examples of the “first position” and the “second position”, respectively. The biasing spring69is an example of the “first biasing member”. The cam part32is an example of the “cam part”. The biasing spring64is an example of the “second biasing member”. The return spring85is an example of the “third biasing member”. The rod part831and the turnable part833are examples of the “rod part” and the “turnable part”, respectively. The upper guide136and the lower guide137are an example of the “pair of guide parts”. The roller holder62is an example of the “roller-support member”. The moving axis A2is an example of the “moving axis of the actuation part”. The shaft611is an example of the “shaft”. The support block71is an example of the “movable member”. The lever75and the locking block73are examples of the “operation member” and the “lock member”.

The above-described embodiment is merely an example, and a driving tool according to the present invention is not limited to the structure of the nailing machine1of the above-described embodiment. For example, the following modifications or changes may be made. Further, only one or more of these modifications or changes may be applied in combination with the nailing machine1of the above-described embodiment or the claimed invention.

The driving tool may be a driving tool for driving out a fastener other than the nail101. For example, the driving tool may be embodied as a tacker or a staple gun for driving out a rivet, pin or staple. Further, the driving source of the flywheel40is not particularly limited to the motor2. For example, an AC motor may be adopted in place of the DC motor. A motor having a brush may be adopted.

The structure of the driver3may be appropriately changed. For example, the cam part32of the roller-abutting part31of the driver3may be formed linearly in its entirety, or in a gentle circular arc shape at least in part, when viewed from the side. In other words, an upper surface of the cam part32(an abutment surface which abuts on the roller63) may be flat or curved in its entirety, or flat or curved in part. Further, the cam part32may have an inclination which varies halfway. The cam part32may be formed longer than that in the above-described embodiment, or the roller-abutting part301may include a plurality of cam parts each having a thickness gradually increasing toward the rear. The driver3may include a single roller-abutting part31, in place of the pair of roller-abutting parts31. Further, the shape and arrangement of the striking part34and the arms35may be appropriately changed.

Various modifications may also be made to the pressing mechanism6.

For example, the holder base61and the roller holder62may have any selected shape. The holder base61does not need to be movable in the up-down direction, as long as the holder base61is turnably supported relative to the tool body11(the support wall13). Specifically, the holder base61may be turnably supported by the tool body11, the support wall13or other member fixed to the tool body11directly via the shafts611(or a separate shaft from the holder base61). In a case where the holder base61is movable in the up-down direction, a structure for moving the holder base61in the up-down direction is not limited to the locking blocks73and the lever75.

The number of the roller63is not limited to one, but may be more (for example, two).

The biasing spring64does not need to be a disc spring, but may be a spring of a different kind (such as a compression coil spring, a tension coil spring, a flat spring and a torsion spring). Further, the biasing spring64may be a spring having a linear characteristic.

Furthermore, a plurality of biasing springs64may be provided.

Similarly, the biasing spring69may be a spring of a different kind (such as a tension coil spring, a flat spring, a torsion spring and a disc spring). Further, the arrangement position and the number of the biasing spring69may also be appropriately changed.

Various modifications may also be made to the solenoid8. For example, the turnable part833may be omitted, as long as the front end portion of the plunger83is linearly movable to turn the holder base61from the separate position to the pressing position when the solenoid8is activated. The front end portion of the plunger83may be configured to turn the holder base61via a member other than the turnable part833. The solenoid8may be disposed, for example, in front of the pressing mechanism6, or such that the moving axis of the plunger83extends in a direction other than the front-rear direction.

Further, in the above-described embodiment, the driver-driving mechanism4is employed in which the roller63presses the driver3directly against the flywheel5and thereby enables transmission of the rotational energy to the driver3. The rotational energy may, however, be transmitted from the flywheel5to the driver3via a transmitting member disposed between the driver3and the flywheel5. For example, a driver-driving mechanism may be employed which includes a ring-like transmitting member which is disposed radially outside of the flywheel5. In this case, when the roller63presses the driver3toward the flywheel5, the driver3and the flywheel5are both frictionally engaged with the ring-like member, so that the rotational energy is transmitted from the flywheel5to the driver3. Such a driver-driving mechanism is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2018-12187.

Further, in view of the nature of the present invention and the above-described embodiment, the following features (aspects) are provided. Only one or more of the following features may be adopted in combination with any of the nailing machine1of the above-described embodiment, its modifications and the claimed invention.

The second biasing member is disposed between the holder and the roller.

The solenoid is disposed rearward of the pressing mechanism.

The turnable part is configured to be turned by receiving a biasing force of the first biasing member via the holder when the holder is located in the second position, thereby generating resistance, and the third biasing member is configured to return the actuation part to the initial position against the biasing force of the first biasing member.

DESCRIPTION OF NUMERALS