Driving tool

Abstract

[Problem] Providing a further improved technique for a process of driving out a fastener in a driving tool. [Solution] A nailing machine 100 has a compression cylinder 131, a driving cylinder 121, a crank mechanism 115, and an electric motor 111, which drives a compression piston inside the compression cylinder 131, and a magnetic sensor 150 that detects the position of the crank mechanism 115. The nailing machine 100 detects the position of the compression piston 133 based on the position of the crank mechanism 115, which is detected by the magnetic sensor 150, and before starting a nail-driving operation, it performs a return operation of moving the compression piston 133 to bottom dead center if the position of the compression piston 133, as detected by the magnetic sensor 150, is a position other than bottom dead center.

Description

TECHNICAL AREA

[0001] The present invention relates to a driving tool for driving out fasteners. STATE OF THE ART

[0002] US Patent No. 8,079,504 B1 discloses a driving tool for driving fasteners into a workpiece. In this driving tool, compressed air, generated by a first piston within a first cylinder, is supplied to a second cylinder, and the compressed air moves a second piston within the second cylinder. This movement of the second piston strikes a fastener, driving the fastener out toward the workpiece. Furthermore, the driving tool includes a sensor that detects the position of the first piston during a fastening cycle. A controller interrupts the power supply to a motor according to the position of the first piston detected by the sensor, so that the first piston stops in a suitable position for the next operating cycle.

[0003] Another driving tool is disclosed in US 2011 / 0 108 600 A1. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] In a drive tool described in US 8,079,504 B1, if the first piston fails to stop in a prescribed position, excess or insufficient compressed air can occur in the next operating cycle. This can cause a problem in the operation of driving out a fastener.

[0005] Accordingly, it is an object of the present invention to provide a further improved technique with regard to a working process of driving out a fastening element in a driving tool. INVENTION TO SOLVE THE PROBLEM

[0006] To solve the problem described above, a driving tool according to claim 1 is provided.

[0007] According to a preferred aspect of the present invention, a driving tool comprises a first cylinder, a first piston arranged to slide within the first cylinder, a drive mechanism driving the first piston, a second cylinder connected to the first cylinder, a second piston arranged to slide within the second cylinder, a valve assembly located in a region where the first cylinder connects with the second cylinder, and a sensor detecting the position of the first piston. The first cylinder is configured to generate compressed air by sliding the first piston when the valve assembly is closed. The second piston is configured to be moved by the compressed air when the valve assembly opens and the compressed air from the first cylinder is supplied to the second cylinder.A fastener is configured to be driven out through an injection port when the second piston is moved by compressed air. Furthermore, before initiating the fastener drive operation, the drive tool performs a return operation of moving the first piston to its bottom dead center (BDC) position if the position of the first piston, as detected by the sensor, is different from BDC. This return operation is initiated at the same time the sensor detects the position of the first piston.

[0008] According to the present invention, the first piston is positioned at bottom dead center before the ejection process begins, so that the amount of air in the first cylinder, compressed by the first piston, can be kept constant during the ejection process. This allows fasteners to be ejected at a predetermined speed in each ejection process. Specifically, in the ejection tool, the drive mechanism may stop abruptly due to a dead battery or unintentional battery removal during a fastener ejection process, or other problems may occur during the ejection process. Under such circumstances, the first piston may not be stopped at or remain at bottom dead center.Even in such a case, the first piston is moved to bottom dead center before the expulsion process begins, so that the amount of air in the first cylinder, which is compressed by the first piston, can be kept constant.

[0009] Furthermore, by providing the structure in which the return process is started at the same time as the sensor detects the position of the first piston, it is not necessary to provide a storage device for storing the detected position of the first piston.

[0010] According to a further aspect of the driving tool of the present invention, the drive mechanism comprises a motor and a crank assembly driven by the motor. The sensor detects the position of a rotating shaft of the motor in a direction of rotation, the position of the crank assembly, or the position of the first piston.

[0011] According to this aspect, the sensor is configured to detect the position of the first piston by sensing the position of the drive mechanism. In such a structure, it is not necessary to directly detect the position of the first piston. In other words, the position of the first piston can be easily detected without directly sensing its position. Furthermore, the sensor can detect the position of the first piston directly.

[0012] According to a further aspect of the driving tool of the present invention, the driving tool has a trigger lever for controlling the driving process. The driving tool further has a single-driving mode, in which a fastener is driven out through the injection port with each actuation of the trigger lever, and a continuous driving mode, in which a single actuation of the trigger lever at the beginning drives out a plurality of fasteners through the injection port. Before starting the first driving process in the continuous driving mode or the driving process in the single-driving mode, the driving tool performs the return process of moving the first piston to bottom dead center if the sensor detects that the first piston is in a position other than bottom dead center.

[0013] According to this aspect, in the continuous ejection mode, the return process is only executed before the first ejection operation, so that the return process is not executed during a series of ejection operations. Specifically, it is not necessary to execute the return process before each ejection operation in the continuous ejection mode, so that the continuous ejection operations can be executed uniformly.

[0014] According to another aspect of the present invention, a battery for powering the drive mechanism is configured to be detachable and the driving tool is configured to perform the return operation when the battery is installed.

[0015] According to this principle, the driving tool performs the return stroke when the battery is installed, ensuring the first piston is positioned at bottom dead center before the ejection stroke begins. Specifically, the battery may be removed from the driving tool due to a depleted battery or unintentional removal. In such a case, the first piston cannot be at bottom dead center. Therefore, in this respect, the first piston is moved to bottom dead center whenever the battery is installed. This ensures that the volume of air in the first cylinder, compressed by the first piston, remains constant during the ejection stroke.

[0016] According to a further aspect of the driving tool of the present invention, the first piston is moved to bottom dead center in such a way that it does not compress the air in the first cylinder during the return stroke. For example, when the first piston is on the path along which it is moved by the drive mechanism from bottom dead center to top dead center, the first piston is moved to bottom dead center by driving the drive mechanism in the opposite direction to that in the ejection stroke. Furthermore, when the first piston is on the path along which it is moved by the drive mechanism from top dead center to bottom dead center, the first piston is moved to bottom dead center by driving the drive mechanism in the same direction as in the ejection stroke.

[0017] According to this principle, the first piston moves to bottom dead center without passing top dead center. Therefore, air in the first cylinder is not compressed when the first piston moves to bottom dead center. Consequently, a fastener can be prevented from being unintentionally ejected when the first piston moves to bottom dead center.

[0018] According to a further aspect of the driving tool of the present invention, the driving tool includes an information means for informing the user about the return process. Preferably, the information means can be a light-emitting means, a vibration-generating means, or a noise-generating means for informing the user about the current return process. The light-emitting means typically includes an LED and a laser beam device. The vibration-generating means typically includes a means that has a motor and generates vibration by rotating the motor. The noise-generating means typically includes a means that has a loudspeaker and outputs a stored sound source through the loudspeaker.

[0019] According to this aspect, the information tool informs the user about the current return process. EFFECT OF INVENTION

[0020] A further improved technique is provided in a driving tool with regard to the process of driving out a fastening element.

[0021] Further tasks, features and advantages of this invention will be more easily understood after reading the following detailed description together with the attached figures and claims. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is an external view showing the entire structure of a nail machine. Fig. 2 is one from one direction of an arrow A in Fig. 1 view seen. Fig. Figure 3 is a cross-sectional view showing the overall structure of an internal mechanism of the nailing machine. Fig. Figure 4 is a cross-sectional view along line IV-IV in Fig. 3. Fig. Figure 5 is a cross-sectional view along line VV in Fig. 2. Fig. Figure 6 is a cross-sectional view along line VI-VI in Fig. 3 in a closed state of a valve. Fig. 7 is one to Fig. 6 similar views showing a nail driving state in which the valve is open and a driving piston is moved forward. Fig. 8 is one to Fig. 6. Similar view showing a state in which the valve is held open and a drive piston has returned close to a rear initial position. REPRESENTATIVE FORM OF EXECUTION FOR IMPLEMENTING THE INVENTION

[0022] Each of the additional features and process steps disclosed above and below can be used separately or in combination with other features or process steps to advance improved driving tools and the devices used therein. Representative examples of this invention, which use many of these additional features and process steps in combination, are now described in detail with reference to the figures. This detailed description is intended only to provide a person skilled in the art with further details on carrying out preferred aspects of the present teachings and is not intended to limit the scope of protection of the invention. Only the claims define the scope of protection of the claimed invention.Therefore, combinations of features and steps disclosed within the following detailed description may not be necessary to carry out the invention in the broadest sense and are instead taught only to describe representative examples of the invention in particular, which detailed description is now given with reference to the attached figures.

[0023] One embodiment of the present invention will now be described with reference to Fig. 1 to 8 are described. In this embodiment, an electric / pneumatic nailing machine is described as a representative example of a driving tool according to the present invention. As in Fig. 1 and Fig. As shown in Figure 2, a nailing machine 100 mainly comprises a body housing 101 and a magazine 105. The body housing 101 is defined as a tool body and forms an outer housing of the nailing machine 100. The magazine 105 is loaded with nails (not shown) to be driven into a workpiece. The body housing 101 is formed by joining together a pair of substantially symmetrical housings. The body housing 101 integrally includes a handle 103, a drive mechanism housing part 101A, a compression device housing part 101B, and a motor housing part 101C.

[0024] The handle 103, the drive mechanism housing part 101A, the compression device housing part 101B, and the motor housing part 101C are arranged to form a substantially rectangular shape, with these four parts on their respective sides. The handle 103 is an elongated component of a predetermined length. One end of the handle 103 is connected along its extension to an end region of the drive mechanism housing part 101A, and the other end is connected along its extension to an end region of the motor housing part 101C. The compression device housing part 101B is arranged to extend substantially parallel to the handle 103.One end of the compression housing part 101B is connected in its direction of extension to the other end region of the drive mechanism housing part 101A, and the other end region is connected in its direction of extension to the other end region of the motor housing part 101C. Thus, the nail gun 100 has a substantially rectangular space S which, when viewed from the side, is enclosed by the handle 103, the drive mechanism housing part 101A, the compression housing device part 101B, and the motor housing part 101C.

[0025] As in Fig. As shown in Figure 1, the nail gun 100 has a drive guide 141 and an LED 107 at its front end (right end when in Fig. 1 seen) on. In Fig. 1 is a nail-driving direction, a direction to the right. Furthermore, for the sake of simplicity, the front end of the nailing machine 100 (the right side when in Fig. 1 seen) is referred to as the front side or front area and its opposite side (the left side when viewed from above). Fig. (as seen in Figure 1) is referred to as the rear side or rear area. This is the side of a connection between the handle 103 and the drive mechanism housing part 101A (top side when viewed in Figure 1). Fig. 1) is referred to as the upper side or upper area and the side of a connection between the handle 103 and the motor housing part 101C (lower side when in Fig. 1 seen) is referred to as the bottom side or lower area.

[0026] As in Fig. As shown in Figure 3, the drive mechanism housing part 101A accommodates the nail driving mechanism 120. The nail driving mechanism 120 mainly comprises a driving cylinder 121 and a driving piston 123. The driving cylinder 121 and the driving piston 123 are exemplary embodiments that correspond to the “second cylinder” and the “second piston” respectively according to the present invention.

[0027] The driving piston 123 for driving nails is housed in the driving cylinder 123 and can slide backwards and forwards. The driving piston 123 comprises a piston body 124, which is arranged to slide within the driving cylinder 121, and an elongated driving element 125, which is integrally formed with the piston body 124 and extends forwards from the piston body 124. Furthermore, the driving piston 123 moves linearly in a longitudinal direction within the driving cylinder 121 by means of compressed air supplied to a cylinder chamber 121a. This causes the driving element 125 to move forwards within a driving passage 141A of the driving guide 141, driving out the nail. The cylinder chamber 121a is defined as a space enclosed by an inner wall surface of the driving cylinder 121 and a rear surface of the piston body 124.The driver guide 141 is arranged at the front end of the driver cylinder 121 and has the driver passage 141a, which has a nail injection opening at its front end.

[0028] As in Fig. As shown in Figure 1, the magazine 105 is located at the front end of the body housing 101 or in front of the compression device housing part 101B. Furthermore, the magazine is connected to the drive guide 141 and configured to feed nails into the drive passage 141a. Specifically, as shown in Fig. As shown in Figure 3, the magazine 105 has an ejector plate 105a for ejecting nails in the loading direction (upwards when in Fig. 3 seen). The ejector plate 105a feeds the driving passage 141a of the driving guide 141 with one nail after another from a direction that crosses the nail driving direction.

[0029] As in Fig. As shown in Figure 3, the compression device housing part 101B accommodates a compression device 130. The compression device 130 mainly comprises a compression cylinder 131, a compression piston 133, and a crank mechanism 115. The compression piston 133 is arranged in the compression cylinder 131 and can slide in a vertical direction. The compression cylinder 131 and the compression piston 133 are exemplary embodiments corresponding to the "first cylinder" and the "first piston," respectively, according to the present invention.

[0030] The compression cylinder 131 is arranged parallel to the magazine 105. The upper end region of the compression cylinder 131 is connected to the front end region of the drive cylinder 121. The compression piston 133 is arranged to slide vertically along the magazine 105. The sliding direction of the compression piston 131 is essentially perpendicular to the sliding direction of the drive piston 123. The capacity of a compression chamber 131a, or an internal space of the compression cylinder 131, is changed by the sliding movement of the compression piston 133 in the vertical direction. Specifically, the compression piston 133 compresses air in the compression chamber 131a by moving upwards to reduce the capacity of the compression chamber 131a. The compression chamber 131a is located adjacent to the drive cylinder 121 in an upper region of the compression cylinder 131.Furthermore, the compression cylinder 131 has an atmosphere opening valve (not shown) through which the compression chamber 131a can be opened to the atmosphere. The opening valve is normally held closed.

[0031] As in Fig. As shown in Figure 3, the motor housing part 101C accommodates the electric motor 111. The electric motor 111 is arranged such that its axis of rotation extends substantially parallel to an axis of the drive cylinder 121. Therefore, the axis of rotation of the electric motor 111 is perpendicular to the sliding direction of the compression piston 133. Furthermore, a battery mounting part is provided at a lower end of the motor housing part 101C, and a rechargeable battery pack 110, from which the electric motor 101 is supplied with energy, is detachably attached to this battery mounting part. The battery pack 110 is an exemplary embodiment that corresponds to the "battery" according to the present invention.

[0032] As in Fig. As shown in Figure 3, the rotational speed of the electric motor 111 is reduced by a planetary gear-type speed reduction mechanism 113, and the rotation is then transmitted to the crank mechanism 115. The rotation of the electric motor 111 is then converted into linear motion by the crank mechanism 115 and transmitted to the compression piston 133. The speed reduction mechanism 113 and the crank mechanism 115 are housed in an inner casing 102, which extends across a rear portion of the compression device housing part 101B and a front portion of the motor housing part 101C.

[0033] The crank mechanism 115 mainly comprises a crankshaft 115a, an eccentric pin 115b, and a connecting rod 115c. The crankshaft 115a is connected to a planetary gear-type speed reduction mechanism 113 and is rotated by the rotation of the electric motor 111, which is slowed down by the speed reduction mechanism 113. The eccentric pin 115b is positioned offset from the center of rotation of the crankshaft 115a. One end of the connecting rod 115c is connected to the eccentric pin 115b so that it is relatively rotatable, and the other end is connected to the compression piston 133 so that it is relatively rotatable. The crank mechanism 115 is located below the compression cylinder 131.With the structure described above, the compression device 130 is of the reciprocating type and mainly comprises the compression cylinder 131, the compression piston 133, and the crank mechanism 115. The crank mechanism 115 and the electric motor 111 are exemplary embodiments corresponding to the "drive mechanism" according to the present invention. Furthermore, the crankshaft 115a and the electric motor 111 are exemplary embodiments corresponding to the "crank assembly" and the "motor" respectively according to the present invention.

[0034] A trigger lever 103a, a trigger lever switch 103b, and a control unit 109 are provided on the handle 103. The control unit 109 controls the starting and stopping of the electric motor 111 in response to an actuation by the user of the trigger lever 103a, which is provided on the handle 103, and the drive guide 141, which is provided on a front end region of the body housing 101. Specifically, the trigger lever switch 103b is turned on and off by pressing and releasing the trigger lever 103a. The trigger lever 103a is designed to project inwards into the space S, which is surrounded by the handle 103, the drive mechanism housing part 101A, the compression device housing part 101B, and the motor housing part 101C.

[0035] The drive guide 141, which also serves as a contact arm, is arranged in the front end region of the body housing 101, so that it can move in the front-back direction of the nail gun 100. As in Fig. As shown in Figure 6, the drive guide 141 is biased forward by a preload spring 142. When the drive guide 141 is in a forward position, a contact arm switch 143 is off. When the drive guide 141 is moved toward the side of the body housing 101, the contact arm switch 143 is on. The electric motor 111 is powered when both the trigger lever switch 103b and the contact arm switch 143 are on, while the electric motor 111 is stopped when either the trigger lever switch 103b or the contact arm switch 143 is off.

[0036] As in Fig. As shown in Figure 5, the nailing machine 100 has an air passage 135 connecting the compression chamber 131a of the compression cylinder 131 and the cylinder chamber 121a of the drive cylinder 121, and a valve chamber 137a.

[0037] As in Fig. As shown in Figure 5, the air passage 135 mainly comprises a connecting opening 135a, a connecting opening 135b, a connecting path 135c, an annular groove 121c, and the valve chamber 137a. As shown in Fig. As shown in Figure 4, the connecting opening 135a is formed in a cylinder head 131b of the compression cylinder 131 and is connected to the compression chamber 131a. As shown in Fig. As shown in Figure 5, the connecting opening 135b is formed in a cylinder head 121b of the drive cylinder 121. The connecting opening 135b is connected to the valve chamber 137a. The connecting path 135c connects the connecting openings 135a and 135b. The connecting path 135c is formed by a tube-like component and extends linearly in the front-to-back direction along the drive cylinder 121.

[0038] As in Fig. As shown in Figure 5, the connecting opening 135b is connected to an annular groove 121c formed in an inner circumferential surface of the valve chamber 137a. The annular groove 121c is connected to the valve chamber 137a. Furthermore, the valve chamber 137a is connected to the cylinder chamber 121a. Thus, the connecting opening 135b is connected to the cylinder chamber 121a via the annular groove 121c and the valve chamber 137a. A solenoid valve 137 for opening and closing the air passage 135 is arranged in the valve chamber 137a. The solenoid valve 137 is an exemplary embodiment that corresponds to the "valve component" according to the present invention.

[0039] The solenoid valve 137 is configured as a column-shaped component, having essentially the same diameter as the piston body 124 of the drive piston 123, and is arranged to be movable in the forward-reverse direction of the valve chamber 137a. An electromagnet 138 is arranged at the rear of the solenoid valve 137. The solenoid valve 137 moves in the forward-reverse direction by switching between supplying and interrupting current to the electromagnet 138. Two O-rings 139a, 139b are provided on an outer circumference of the solenoid valve 137 at a predetermined distance in the forward-reverse direction. The solenoid valve 137 opens the annular groove 121c by moving backward and closes the annular groove 121c by moving forward.

[0040] Specifically, as in Fig. Figure 6 shows that when the front O-ring 139a is positioned in front of the annular groove 121c and is in contact with an inner wall surface of the valve chamber 137a, the connection between the annular groove 121c and the cylinder chamber 121a is interrupted. Furthermore, as shown in Fig. As shown in Figure 7, when the O-ring 139a is moved into a region of the annular groove 121c, the annular groove 121c is connected to the cylinder chamber 121a. Furthermore, the rear O-ring 139b is provided to prevent compressed air from escaping through the connecting opening 135b and does not affect the opening and closing of the annular groove 121c. As described above, the solenoid valve 137 is provided for opening and closing the air passage 135 in a region of the air passage 135 that is connected to the cylinder chamber 121a of the drive cylinder 121.

[0041] As in Fig. As shown in Figure 6, the solenoid valve 137, which closes the annular groove 121c, is normally in a forward position by the electric solenoid 138. Furthermore, a stop 136 is provided in front of the solenoid valve 137 and prevents further forward movement of the solenoid valve 137. The stop 136 is formed by a flange-like component that projects radially inward into the cylinder chamber 121a. The stop 136 also defines the rear end position of the driving piston 123, which moves backward.

[0042] When the driving piston 123 is in the rear end position (left end position when in Fig. 3 seen) and the compression piston 133 is in the lower end position (bottom dead center), as in Fig. As shown in Figure 3, the nailing machine 100 is defined as being in an initial position. Specifically, the nailing machine 100 is defined as being in an initial state when the crank angle is zero degrees (at bottom dead center).

[0043] In the initial state, as in Fig. 3 shown when the contact arm switch 143 (see Fig. 6) When the drive guide 141 is pressed against the workpiece and the trigger lever switch 103b is pressed by pressing the trigger lever 103a, current is supplied to the electric motor 111, thus driving the electric motor 111. This drives the crank mechanism 115 via the speed reduction mechanism 113 and moves the compression piston 133 upwards. At this point, the air passage 135 is closed by the solenoid valve 137, so that air in the compression chamber 131a is compressed by the movement of the compression piston 133.

[0044] When the compression piston 133 reaches its upper end position (top dead center), at which the crank angle is 180 degrees, or when the air in the compression chamber 131a is compressed to its maximum, the solenoid valve 137 is moved backward by the electromagnet 138. Consequently, the annular groove 121c is connected to the cylinder chamber 121a, and the compressed air in the compression chamber 131a is supplied to the cylinder chamber 121a via the air passage 135. When the compressed air is supplied to the cylinder chamber 121a, as in Fig. As shown in Figure 7, the driving piston 123 is moved forward by an air spring effect of the compressed air. Then the driver 125 of the driving piston 123 strikes the nail in the driver passage 141a of the driver guide 141, so that a driving process of driving out the nail is carried out and the nail is driven into the workpiece.

[0045] After the extension process, the compression piston 133 moves towards bottom dead center. At this point, the capacity of the compression chamber 131a increases, so that the pressure in the compression chamber 131a is reduced below atmospheric pressure. The pressure in the compression chamber 131a acts on the insertion piston 123 via the air passage 135 and the cylinder chamber 121a. Consequently, as in Fig. As shown in Figure 8, air from cylinder chamber 121a is drawn into compression chamber 131a, and the driving piston 123 is moved to the rear. The driving piston 123 then comes into contact with the stop 136 and is held in the initial position. The solenoid valve 137 maintains the connection between the air passage 135 and cylinder chamber 121a until the driving piston 123 is moved to the initial position. However, when the driving piston 123 reaches the initial position, the solenoid valve 137 moves forward, interrupting the connection between the air passage 135 and cylinder chamber 121a. Furthermore, when the compression piston 133 returns to the initial position, the power supply to the electric motor 111 is interrupted, and the electric motor 111 is stopped, even if the trigger lever switch 103b and the contact arm switch 143 remain in the on state. In this way, one cycle of the expulsion process is completed.Furthermore, the LED 107 illuminates the tip end area of ​​the drive guide 141 during a drive-out process.

[0046] In the nailing machine 100 described above, the power supply to the electric motor 111 may be interrupted during a nail-driving operation for various reasons, such as a depleted battery in the battery pack 110 or unintentional removal of the battery pack 110. Other problems may also occur during a nail-driving operation. In such a case, the compression piston 133 may not be at bottom dead center. If this happens, when the driving operation is restarted, the degree of compression of the compressed air generated by the compression piston 133 varies depending on the piston's position at the beginning of the driving operation. Therefore, the driving speed of the nails differs in each driving operation, resulting in variations in the depth to which the nails are driven into the workpiece.Therefore, before the start of the extension process, if the compression piston 133 is not at bottom dead center, a return process is performed to move the compression piston 133 to bottom dead center. Furthermore, the return process is executed in a state where the atmosphere opening valve, which is formed in the compression cylinder 133, is opened to open the compression chamber 131a to the atmosphere.

[0047] Specifically, as in Fig.As shown in Figure 3, the nail gun 100 has a magnetic sensor 150. The magnetic sensor 150 mainly comprises a magnet 151 and a Hall effect sensor 152. The magnet 151 is arranged on the crankshaft 115a, and the Hall effect sensor 152 is arranged opposite the magnet 151 in the compression device housing part 101B. The Hall effect sensor 152 is electrically connected to the battery pack 110 and further to the control unit 109. The magnetic sensor 150 is an exemplary embodiment that corresponds to the “sensor” according to the present invention.

[0048] Before the extraction process begins, the magnetic sensor 150 detects the position of the crankshaft 115a via the magnetic field of the magnet 151, based on the Hall effect induced by the Hall element 152. Specifically, the controller 109 detects the position of the crankshaft 115a based on the output voltage of the Hall element 152 according to the magnetic flux density, since the magnetic flux density varies according to the position of the magnet 151. From this detection, the position of the compression piston 133, which is connected to the crankshaft 115a, is determined.

[0049] The magnetic sensor 150 detects the position of the compression piston 133 before the removal process. Specifically, the magnetic sensor 150 measures the position of the crankshaft 115a at the following times: Time 1: when the battery pack 110 is attached to the battery mounting part Time 2: when the trigger lever 103a is actuated Point in time 3: when the driver guide 141 is pressed against the workpiece

[0050] The magnetic sensor 150 detects the position of the crankshaft 115a at least at one of the three time points 1 to 3. Specifically, the magnetic sensor 150 detects the position of the crankshaft 115a at one or more time points selected from time points 1 to 3. The time point at which the magnetic sensor 150 detects the position of the crankshaft 115a is preset in the control unit 109.

[0051] For example, during the removal of a fastener, the compression piston 133 may stop in a position other than bottom dead center due to a depleted battery in the battery pack 110 or unintentional removal of the battery pack 110. Therefore, at time 1, the magnetic sensor 150 detects the position of the crankshaft 115a to detect the position of the compression piston 133. If the compression piston 133 is in a position other than bottom dead center, the control unit 109 drives the electric motor 111 to move the compression piston 133 to bottom dead center.

[0052] The nailing machine 100 is configured so that, after completion of a driving operation, the compression piston 133 moves from top dead center to bottom dead center and stops at bottom dead center. However, the compression piston 133 cannot stop precisely at bottom dead center due to the inertial force caused by its movement. Furthermore, if the trigger lever 103 is stopped or the drive guide 141 is released from the workpiece after the driving operation has started, the compression piston 133 stops during the driving operation. In such a case, if the user acts the trigger lever 103a at time 2 to start the driving operation, the magnetic sensor 150 detects the position of the crankshaft 115a. In this case, the magnetic sensor 150 can detect the position of the crankshaft 115a without detecting it at time 2.The position of the compression piston 133 is detected by sensing the position of the crankshaft 115a. If the compression piston 133 is in a position other than bottom dead center, the control unit 109 drives the electric motor 111 to move the compression piston 133 to bottom dead center.

[0053] Furthermore, the nailing machine 100 can perform a continuous driving operation for the continuous driving of nails at freely selectable time intervals. Specifically, to perform a continuous driving operation after a previous driving operation, the driving guide 141 is released from the workpiece while the trigger lever 103a is held down, and then the driving guide 141 is pressed against another part of the workpiece again, so that the next driving operation is carried out. In other words, in a normal driving operation, one nail is driven out with each actuation of the trigger lever 103a, whereas in a continuous driving operation, multiple nails are driven out by a single actuation of the trigger lever 103a at the beginning.In this continuous ejection process, at time 2, when the user actuates the trigger lever 103a to start the first ejection process, the magnetic sensor 150 detects the position of the crankshaft 115a. Thus, the magnetic sensor 150 detects the position of the crankshaft 115a only before the start of the first of the continuous ejection processes. Furthermore, in the continuous ejection process, the magnetic sensor 150 can detect the position of the crankshaft 115a at time 3, when the drive guide 141 is pressed against the workpiece before each ejection process. In the continuous ejection process, the magnetic sensor 150 can detect the position of the crankshaft 115a at times 2 and 3. The position of the compression piston 133 is determined by detecting the position of the crankshaft 115a.If the compression piston 133 is in a position other than bottom dead center, the control unit 109 drives the electric motor 111 to move the compression piston 133 to bottom dead center.

[0054] During the return process from moving the compression piston 133 to bottom dead center, the control unit 109 moves the compression piston 133 in such a way that air in the compression chamber 131a is not compressed. Specifically, the compression piston 133 is moved to bottom dead center without passing top dead center.

[0055] More precisely, if the magnetic sensor 150 detects that the crankshaft 115a is in a position where the crank angle is in the range of 0 to 180 degrees, or detects that the compression piston 133 is on its way from bottom dead center to top dead center in the extension process, the control unit 109 rotates the electric motor 111 in the opposite direction to moving the compression piston 133 to bottom dead center.

[0056] If the magnetic sensor 150 detects that the crankshaft 115a is in a position where the crank angle is between 180 and 360 degrees, or detects that the compression piston 133 is moving from top dead center to bottom dead center during the extension process, the control unit 109 rotates the electric motor 111 in the normal direction to move the compression piston 133 to bottom dead center. By controlling the electric motor 111 as described above, the compression piston 133 is moved to bottom dead center without passing top dead center.

[0057] The return process described above selectively includes a first return process of moving the compression piston 133 to bottom dead center at a single point in time, and a second return process of intermittently moving the compression piston 133 to bottom dead center. Specifically, in the first return process, the compression piston 133 is initially accelerated, then moved at a constant velocity, and subsequently decelerated and stopped at bottom dead center. In the second return process, the compression piston 133 is repeatedly moved and stopped at a constant velocity and finally stopped at bottom dead center. Thus, the compression piston 133 is moved intermittently in the second return process.

[0058] If it is detected that the compression piston 133 is in a position other than bottom dead center when the user starts the ejection process, the compression piston 133 is moved to bottom dead center by the first return operation. Specifically, the first return operation is executed at times 2 and 3. It is necessary to move the compression piston 133 quickly to bottom dead center when the user starts the ejection process. Therefore, it is advantageous to move the compression piston 133 to bottom dead center using the first return operation.

[0059] If it is detected that the compression piston 133 is in a position other than bottom dead center when the battery pack 110 is attached, the compression piston 133 is moved to bottom dead center by the second return operation. Specifically, the return operation to be performed at time 1 is the second return operation. Because the battery pack 110 is attached, it is not known whether the user immediately initiates the ejection operation. Therefore, when the battery pack 110 is attached, the compression piston 133 is moved to bottom dead center by the second return operation. This operation causes vibration due to the intermittent movement of the compression piston 133, which notifies (or informs) the user of the current return operation. The second return operation is an exemplary embodiment that corresponds to the "means of notification" according to the present invention.

[0060] The LED 107 illuminates the tip end region of the drive guide 141 during the ejection process. Furthermore, during the return process, the controller 109 causes the LED 107 to flicker to inform the user about the current return process. The LED 107 is not limited to the flickering function; it can also be configured to change the color of the illumination between the ejection and return processes. The LED 107 is an exemplary embodiment that corresponds to the "information means" according to the present invention.

[0061] According to this embodiment, the compression piston 133 is moved to bottom dead center before the ejection process begins, so that the degree of air compression by the compression piston 133 can be kept constant during the ejection process. Thus, fasteners can be ejected at a predetermined speed in each ejection process.

[0062] According to this embodiment, it is not necessary for the magnetic sensor 150 to directly detect the compression piston 133, or specifically to detect the position of a component, such as the compression piston 133, which is surrounded by the compression cylinder 133. Therefore, the position of the compression piston 133 can be easily detected by detecting the position of the crankshaft 115a or the motor shaft of the electric motor 111.

[0063] According to this embodiment, the return process is executed when the battery pack 111 is attached, so that the compression piston 133 can be positioned at bottom dead center before the ejection process begins. Specifically, the battery pack 110 may be removed due to a depleted battery or may have been unintentionally removed. Even in such a case, the compression piston 133 can be moved to bottom dead center whenever the battery pack 110 is attached.

[0064] According to this embodiment, the compression piston 133 can be moved to bottom dead center without passing top dead center. Thus, air is not compressed in the compression cylinder 131 when the compression piston 133 is moved. Therefore, a nail can be prevented from being unintentionally driven out when the compression piston 133 is moved.

[0065] According to this embodiment, the LED 107 and the second return process are provided as the means of information which can inform the user about the current return process.

[0066] In the embodiment described above, the solenoid valve 137 is described as the valve component for opening and closing the air passage 135, but a mechanical valve that operates mechanically can be used as the valve component.

[0067] In this embodiment, the second return process is described as being configured to intermittently move the compression piston 133, but it is not limited to this, as long as the second return process is different from the first return process. For example, the second return process can be configured as a process in which the compression piston 133 is moved to bottom dead center while repeating the acceleration and deceleration cycles.

[0068] In this embodiment, the user is informed of the current retraction process by vibration generated by the intermittent movement of the compression piston 133 during the second retraction, and by the illumination of the LED 107, but this is not the only method. For example, an LED 108 can be provided on the rear of the nailing machine 100 and illuminate to inform the user of the current retraction process. Alternatively, a sound source generation device with a loudspeaker can be installed as the information means for the nailing machine 100.

[0069] In this embodiment, the magnetic sensor 150 is configured to detect the position of the crankshaft 115a at the times of attaching the battery pack 110 and actuating the trigger lever 103a and the drive guide 141, but it is not limited to this. For example, a reset switch that can be actuated by a user may be provided, and this may be configured to detect the position of the crankshaft 115a at the time the reset switch is actuated.

[0070] In this embodiment, the magnetic sensor 150 is configured to detect the position of the crankshaft 115a, but it is not limited to this. For example, the magnet 151 can be mounted on the motor shaft of the electric motor 111, and the magnetic sensor 150 can be configured to detect the rotational position of the motor shaft in order to detect the position of the compression piston 133. Or the magnetic sensor 150 can be configured to detect the position of the compression piston 133. Furthermore, instead of the magnetic sensor, a sensor such as a photoelectric sensor, which has a light-receiving part and a light-emitting part, can be used.

[0071] In this embodiment, the magnetic sensor 150 is configured, but not limited to, to move the compression piston 133 to bottom dead center after detecting its position. For example, the magnetic sensor 150 can be configured to detect the position of the compression piston 133 before the battery pack 110 is attached or after a predetermined time has elapsed following completion of a nail drive operation, and to move the compression piston 133 to bottom dead center when the user actuates the trigger lever 103a to initiate the nail drive operation. In this case, it is preferred that the nail gun 100 has a memory device for storing the position of the compression piston 133.

[0072] In this embodiment, the nail gun 100 is described as a representative example of the driving tool, but the present invention can also be applied to a driving tool other than the nail gun, such as a stapler or a tacker. Furthermore, the driving tool is not limited to the type that has a battery pack 110 attached to it, but can also be of the type in which current is supplied via a power cable. The drive mechanism is not limited to the electric motor 111, but an internal combustion engine can also be used.

[0073] With regard to the object of the invention described above, driving tools according to the present invention can have the following features. (Aspect 1)

[0074] Driving tool for driving out a fastener through an injection opening with a first cylinder a first piston which is arranged within the first cylinder in such a way that it is sliding, a drive mechanism that drives the first piston, a second cylinder that is connected to the first cylinder, a second piston which is arranged inside the second cylinder in such a way that it is sliding, a valve component that is located in an area where the first cylinder is in contact with the second cylinder, a sensor that detects the position of the first piston, and a controller that controls the drive mechanism based on a sensor reading, in which the first cylinder is configured to generate compressed air by sliding the first piston into a closed state of the valve component, the second piston is configured to be moved by the compressed air when the valve assembly is open and the compressed air from the first cylinder is supplied to the second cylinder, the fastening element is configured to be driven out through the injection port when the second piston is moved by the compressed air, and The control system is configured to control the drive mechanism so that it performs a return operation of moving the first piston to a bottom dead center of the first piston before starting an operation of driving out the fastener if the position of the first piston detected by the sensor is a position other than the bottom dead center. (Aspect 2)

[0075] Driving tool according to aspect 1, wherein the drive mechanism includes a motor and a crank component driven by the motor, and the sensor is configured to detect a position of a rotating shaft of the motor in a direction of rotation of the rotating shaft, a position of the crank component, or a position of the first piston. (Aspect 3)

[0076] Driving tool according to aspect 1 or 2, in which the control for controlling the drive mechanism is configured so that it starts the return process at the same time as the sensor detects the position of the first piston. (Aspect 4)

[0077] Driving tool according to one of aspects 1 to 3, which further includes a trigger lever for controlling the driving process, in which The control system has a single-expulsion mode in which a fastener is ejected through the injection port with each actuation of the trigger lever, and a continuous-expulsion mode in which a plurality of fasteners are ejected through the injection port with a single actuation of the trigger lever at the beginning, and The control system for controlling the drive mechanism is configured to perform the return operation before starting the first extension operation in continuous extension mode or the extension operation in single extension mode, if the sensor detects that the first piston is in a position other than bottom dead center. (Aspect 5)

[0078] Driving tool according to one of aspects 1 to 4, which further comprises a battery mounting part on which a battery for driving the drive mechanism is detachably mounted, in which the control is configured to control the drive mechanism so that it performs the return process when the battery is mounted on the battery mounting part. (Aspect 6)

[0079] Driving tool according to one of aspects 1 to 5, in which the control for controlling the drive mechanism is configured so that it moves the first piston to the bottom dead center in such a way that air of the first cylinder is not compressed by the return process. (Aspect 7)

[0080] Driving tool according to aspect 6, in which the control for controlling the drive mechanism is configured to drive it in a direction reversed to that in the driving process, in order to move the first piston to the bottom dead center if the sensor detects that the first piston is on its way from the bottom dead center to the top dead center. (Aspect 8)

[0081] Driving tool according to one of claims 1 to 7, which further comprises an information means for providing information about the return process. (Aspect 9)

[0082] Driving tool according to claim 1, wherein the return process comprises a first return process of moving the first piston to the bottom dead center at one time and a second return process of intermittently moving the first piston to the bottom dead center. (Aspect 10)

[0083] Driving tool according to claim 7, wherein the drive mechanism comprises a motor, and if the sensor detects that the first cylinder is on its way from bottom dead center to top dead center, the motor is rotated in the opposite direction to move the first cylinder to bottom dead center. (Aspect 11)

[0084] Driving tool according to aspect 10, in which, if the sensor detects that the first cylinder is on its way from top dead center to bottom dead center, the engine is rotated in the normal direction to move the first cylinder to bottom dead center. (Aspect 12)

[0085] Driving tool according to claim 8, wherein the information medium comprises a light-emitting means. (Aspect 13)

[0086] Driving tool according to aspect 12, in which, when the fastener is driven out, the light-emitting means shines in a first illumination mode of illuminating an area where the fastener is driven out, and when the return operation is carried out, the light-emitting means shines in a second illumination mode different from the first illumination mode. (Aspect 14)

[0087] Driving tool according to claim 8, wherein the information means includes a vibration-generating means for vibrating the driving tool. (Similarities between the features of the embodiment and the features of the invention)

[0088] The embodiment described above is a representative example for carrying out the present invention, and the present invention is not limited to the structure described as the representative embodiment. Similarities between the features of the embodiment and the features of the invention are as follows.

[0089] The compression cylinder 131 is an exemplary embodiment corresponding to the “first cylinder” according to the present invention.

[0090] The compression piston 133 is an exemplary embodiment corresponding to the “first piston” according to the present invention.

[0091] The drive cylinder 121 is an exemplary embodiment that corresponds to the “second cylinder” according to the present invention.

[0092] The driving piston 121 is an exemplary embodiment that corresponds to the “second piston” according to the present invention.

[0093] The solenoid valve 137 is an exemplary embodiment that corresponds to the “valve component” according to the present invention.

[0094] The magnetic sensor 150 is an exemplary embodiment that corresponds to the “sensor” according to the present invention.

[0095] The crank mechanism 115 is an exemplary embodiment that corresponds to the “drive mechanism” according to the present invention.

[0096] The crankshaft 115a is an exemplary embodiment that corresponds to the “crankshaft component” according to the present invention.

[0097] The electric motor 111 is an exemplary embodiment that corresponds to the “drive mechanism” according to the present invention.

[0098] The electric motor 111 is an exemplary embodiment that corresponds to the “motor” according to the present invention.

[0099] The battery pack 110 is an exemplary embodiment of the “battery” according to the present invention.

[0100] The LED 107 is an exemplary embodiment that corresponds to the “information means” according to the present invention.

[0101] The second return process is an exemplary embodiment that corresponds to the “information means” according to the present invention. Reference symbol list 100 nail machine 101 Body casing 101A Drive mechanism housing part 101B Compression Device Housing Part 101C Motor housing 102 Inner casing 103 Handle 103a Trigger lever 103b Trigger lever switch 105 Magazine 105a Ejector plate 107 LED 108 LED 109 Control 110 battery pack 111 Electric Motor 113 Speed ​​reduction mechanism of the planetary gear type 115 Crank mechanism 115a Crankshaft 115b Eccentric Pin 115c Connecting rod 120 nail driving mechanism 121 Drive-in cylinders 121a Cylinder chamber 121b Cylinder head 121c Ring-shaped groove 123 Drive-in pistons 124 piston bodies 125 debt collectors 130 compression device 131 compression cylinders 131a Compression chamber 131b Cylinder head 133 compression pistons 135 Air passage 135a Connecting opening 135b Connecting opening 135c connection path 136 attacks 137 Solenoid valve 137a Valve chamber 138 Electromagnet 139a O-ring 139b O-ring 141 Debt Collection Guide 141a Enforcement Passage 142 Preload spring 143 Contact arm switches 150 magnetic sensor 151 Magnet 152 Hall element

Claims

[1] Driving tool (100) for driving out a fastening element through an injection opening with a first cylinder (131), a first piston (133) which is arranged inside the first cylinder (131) in such a way that it is slidable, a drive mechanism (115) that drives the first piston (133), a second cylinder (121) which is connected to the first cylinder (131), a second piston (123) which is arranged inside the second cylinder (121) in such a way that it is slidable, a valve component (137) which is arranged in an area in which the first cylinder (131) is in communication with the second cylinder (121), and a sensor (150) that detects the position of the first piston (133), in which the first cylinder (131) is configured to generate compressed air by sliding the first piston (133) into a closed state of the valve component (137), the second piston (123) is configured to be moved by the compressed air when the valve component (137) is opened and the compressed air from the first cylinder (131) is supplied to the second cylinder (121), the fastening element is configured to be driven out through the injection port when the second piston (123) is moved by the compressed air, Before starting an operation of driving out the fastener, the driving tool (100) performs a return operation of moving the first piston (133) to a bottom dead center of the first piston (133), if the position of the first piston (133) detected by the sensor (150) is a position other than the bottom dead center, and The return process is started at the same time as the sensor (150) detects the position of the first piston (133). [2] Driving tool (100) according to claim 1, wherein the drive mechanism (115) includes a motor (111) and a crank component (115a) driven by the motor (111), and the sensor (150) is configured to detect a position of a rotating shaft of the motor (111) in a direction of rotation of the rotating shaft, a position of the crank component (115a) or a position of the first piston (133). [3] Driving tool (100) according to claim 1 or 2, further comprising: a trigger lever (103a) for controlling the ejection process, and a single ejection mode in which a fastening element is ejected through the injection opening with each actuation of the trigger lever (103a), and a continuous ejection mode in which a plurality of fastening elements are ejected through the injection opening with the trigger lever (103a) once at the beginning, in which Before starting the first ejection process in the continuous ejection mode or the ejection process in the single ejection mode, the driving tool performs the return process if the sensor (150) detects that the first piston (133) is in a position other than bottom dead center. [4] Driving tool (100) according to any one of claims 1 to 3, wherein a battery (110) for driving the drive mechanism (115) is configured to be removable, and the driving tool (100) is configured to perform the return operation when the battery (110) is attached. [5] Driving tool (100) according to any one of claims 1 to 4, wherein the first piston (133) is moved to the bottom dead center in such a way that air of the first cylinder (131) is not compressed by the return process. [6] Driving tool (100) according to claim 5, wherein, if the sensor (150) detects that the first piston (133) is on its way from bottom dead center to top dead center, the drive mechanism (115) is driven in a direction reversed to that in the driving process in order to move the first piston (133) to bottom dead center. [7] Driving tool (100) according to one of claims 1 to 6, which further comprises an information means (107) for providing information about the return process.

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