JP4671886B2 - Impact tool - Google Patents

Description

  The present invention relates to a striking tool that performs a predetermined machining operation by moving a tool bit linearly in a long axis direction, and more particularly, to a construction technique of an empty striking prevention mechanism that prohibits a striking operation of a tool bit when there is no load.

  2. Background Art A hitting tool having a blanking prevention mechanism that prohibits a hammer bit hitting operation when there is no load is widely known. Such an impact tool is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-212370 (Patent Document 1). The hitting tool described in the publication is a hammer drill, and when the piston moves linearly in the cylinder, the striker moves linearly via the air chamber pressure fluctuation (spring action) and hits the tool bit via the impact bolt. The configuration is such that the rotational movement of the cylinder is transmitted to the tool bit via the tool holder. The cylinder is formed with a breathing hole that communicates the air chamber to the outside. By placing the breathing hole in an open state, the spring action of the air chamber is disabled, and the tool bit is prevented from being punched. The When a tool bit is pressed against the workpiece in order to perform a machining operation on the workpiece, the breathing hole is closed by a valve member that is moved back together with the tool bit toward the main body side, so that the spring of the air chamber The operation is made possible and the tool bit can be struck.

In the above-described hammer drill, when the tool bit is pressed against the workpiece, an annular member engaged with the impact bolt and an outer side of the cylinder are used as means for transmitting the backward movement of the impact bolt moving together with the tool bit to the valve member. And a sleeve whose one axial end (rear end) is engaged with the valve member. The annular member has a protrusion that penetrates the tool holder that houses the impact bolt and extends in the outer diameter direction, and this protrusion is configured to engage with the other axial end (front end) of the sleeve. However, in the configuration in which the protrusion of the annular member passes through the tool holder fitted to the outer periphery of the front end of the cylinder and protrudes outward, and the sleeve engages with the protrusion, a large space is required outside the cylinder. As a result, the housing (barrel portion) that accommodates the cylinder becomes larger in the outer diameter direction, and there is still room for improvement in this respect.
Japanese Patent Laid-Open No. 2003-212370

  In view of this point, an object of the present invention is to provide a technique that contributes to a compact impact tool having a blanking prevention mechanism.

In order to achieve the above object, the invention described in each claim is configured.
According to the first aspect of the present invention, the tool main body, the tool bit arranged in the tip region of the tool main body and performing a predetermined machining operation by linearly moving in the long axis direction, and the tool main body are accommodated. Cylinder, a driver that linearly moves in the long axis direction of the tool bit in the cylinder, and a long axis direction of the tool bit in the cylinder through pressure fluctuations in the air chamber in the cylinder accompanying the linear movement of the driver. A striking tool having a striking element that is linearly operated, and an intermediate element that is disposed between the striking element and the tool bit and transmits the linear motion of the striking element to the tool bit. As the “striking tool” in the present invention, typically, the tool bit performs a hammering operation on the workpiece by performing only a linear striking motion in the long axis direction, or the tool bit is in the long axis direction. This corresponds to a hammer drill that performs a striking motion and a rotational motion around the major axis.

  A striking tool according to the present invention is a valve that is movable between a communicating portion that communicates an air chamber and the outside, an open position that is disposed outside the cylinder and opens the communicating portion, and a closed position that closes the communicating portion. When the tool bit is pressed against the workpiece, it is pushed by the intermediate member that is moved back together with the tool bit when the tool bit is pressed against the workpiece. And an operation relay member that moves the valve member to the closed position against the urging force of the urging member. A plurality of operation relay members are arranged in the outer circumferential direction of the cylinder, and at least a part thereof is buried in the cylinder. The “operation relay member” in the present invention is typically constituted by a rod-like member elongated in the long axis direction of the tool bit, that is, the long axis direction of the cylinder. The rod-shaped member may have any of a circular cross section, an elliptical shape, an arc shape, or a square shape. Further, “at least a part” in the present invention includes both an aspect in which a part of the operation relay member is buried in the cylinder and an aspect in which the whole is buried. Further, as an aspect of “buried”, typically, a groove having a predetermined depth in the radial direction is formed on the outer surface of the cylinder in the longitudinal direction of the cylinder, and an operation relay member is fitted in the groove. This is the case. Moreover, as a mode in which the entirety is filled, a mode in which the operation relay member is flush with the cylinder outer surface, a mode in which the operation relay member is placed in a position deeper than the cylinder outer surface, or the like is suitably included.

According to the present invention, when the tool bit is not pressed against the workpiece, the valve member is held at the open position where the communication portion is opened by the urging force of the urging member. In this state, even if the driver element is linearly operated, the pressure fluctuation (spring action) of the air chamber is not allowed, and the linear movement of the striker is stopped to prevent the tool bit from being shot dry. When the tool bit is pressed against the work piece, the valve member moves to the position where the valve hole closes the vent hole against the urging force via the meson and the operation relay member that is moved to the tool body side together with the tool bit. Moved. Thereby, the spring action of the air chamber is made possible and the striker acts effectively.
According to the present invention, since the operation relay member is embedded in the cylinder, the protrusion amount of the operation relay member to the outside of the cylinder can be suppressed. As a result, the space for disposing the operation relay member in the outer region of the cylinder becomes unnecessary or is reduced, so that the barrel portion of the tool main body housing the cylinder is prevented from spreading in the outer diameter direction to be compact. Is possible. A plurality of operation relay members are arranged at predetermined intervals in the circumferential direction of the cylinder. For this reason, the backward movement of the meson can be transmitted to the valve member in a well-balanced manner, and the thin portion of the cylinder is only partially present in the circumferential direction. Can do.

(Invention of Claim 2)
According to the second aspect of the present invention, the cylinder in the impact tool according to the first aspect is configured to rotate around the long axis direction of the tool bit, and the rotational operation of the cylinder is provided outside the cylinder. It has a power transmission member that transmits to the bit as a rotational motion around the long axis direction. The power transmission member is fitted to the outer periphery of the cylinder in a state where relative movement around the tool bit long axis direction is restricted. The operation relay member is arranged between the cylinder and the power transmission member in a state of being buried in the cylinder. The “power transmission member” in the present invention is an aspect constituted by the tool holder itself that holds the tool bit in a state in which the relative movement of the tool bit around the long axis is restricted, or separate from the tool holder. Any of the embodiments provided as separate members is suitably included. Also, in the aspect provided as a separate member, the aspect of transmitting the rotation operation from the separate member to the tool bit suitably includes any of the aspect of transmitting via the tool holder or the aspect of transmitting via the meson. . Further, the “state embedded in the cylinder” suitably includes an aspect in which the operation relay member is flush with the outer surface of the cylinder, or an aspect in which the operation relay member is placed at a position deeper than the outer surface of the cylinder.
In the present invention, the rotation operation of the cylinder is transmitted to the tool bit as a rotation operation around the long axis direction via the power transmission member, so that the impact operation in the long axis direction of the tool bit and the rotation around the long axis direction are performed. It is possible to perform hammer drill work by rotating operation. According to the present invention, in the impact tool capable of performing a hammer drill operation, the operation relay member is buried between the cylinders and arranged between the cylinder and the power transmission member. The barrel of the tool body can be made compact by suppressing the spread of the power transmission member in the outer diameter direction. If the operation relay member has a configuration in which a part in the cylinder radial direction is buried in the cylinder and a portion excluding the part projects from the outer surface of the cylinder, the projection is buried in the inner diameter side of the power transmission member. A configuration is preferable.

(Invention of Claim 3)
According to the invention described in claim 3, in the impact tool described in claim 2, a long groove extending in the tool bit major axis direction is formed on the outer surface of the cylinder. The motion relay member is configured to be movably accommodated in the long groove without protruding from the outer surface of the cylinder in the outer diameter direction. According to the present invention, since the operation relay member does not protrude from the outer surface of the cylinder, the barrel portion of the tool main body can be made more compact, and a long groove is formed on the inner diameter side of the power transmission member. There is no need to perform the processing, and the processing cost can be reduced.

  According to the present invention, a technique that contributes to the compactness of an impact tool having an idling prevention mechanism has been provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. This embodiment will be described using an electric hammer drill as an example of an impact tool. FIG. 1 is a side sectional view showing the entire configuration of the electric hammer drill according to the present embodiment, and FIG. 2 is a plan sectional view showing the entire configuration of the electric hammer drill. 1 shows a loaded state in which the hammer bit is pressed against the workpiece, and FIG. 2 shows an unloaded state in which the hammer bit is not pressed against the workpiece. As shown in FIG. 1 and FIG. 2, the hammer drill 101 according to the present embodiment generally has a main body 103 that forms an outline of the hammer drill 101 and a tip region (left side in the drawing) of the main body 103. A hammer bit 119 detachably attached via a hollow tool holder 137 and a hand grip 109 gripped by an operator connected to the opposite side of the main body 103 to the hammer bit 119 are mainly configured. The hammer bit 119 is held by a tool holder 137 so as to be relatively linearly movable in the long axis direction. The main body 103 corresponds to the “tool main body” in the present invention, and the hammer bit 119 corresponds to the “tool bit” in the present invention. For convenience of explanation, the hammer bit 119 side is referred to as the front, and the hand grip 109 side is referred to as the rear.

  The main body 103 includes a motor housing 105 that houses the drive motor 111, and a gear housing 107 that houses the motion conversion mechanism 113, the striking element 115, and the power transmission mechanism 117. The rotational output of the drive motor 111 is appropriately converted into a linear motion by the motion conversion mechanism 113 and then transmitted to the striking element 115, and the major axis direction of the hammer bit 119 (the left-right direction in FIG. 1) via the striking element 115. Generates an impact force on. The rotation output of the drive motor 111 is transmitted to the hammer bit 119 after being appropriately decelerated by the power transmission mechanism 117, and the hammer bit 119 is rotated in the circumferential direction. The drive motor 111 is energized and driven by a pulling operation of a trigger 109 a disposed on the hand grip 109.

  FIG. 3 is a sectional view showing an enlarged state of the main part of the hammer drill 101. The motion conversion mechanism 113 is composed mainly of a drive gear 121, a driven gear 123, a crank plate 125, a crank arm 127, and a piston 129 that are rotationally driven in a horizontal plane by a drive motor 111. The crank plate 125, the crank arm 127 The piston 129 constitutes a crank mechanism. The piston 129 is slidably disposed in the cylinder 141, and performs a linear motion in the long axis direction of the hammer bit along the cylinder 141 when the drive motor 111 is energized. The piston 129 corresponds to the “driver” in the present invention.

  The striking element 115 includes a striker 143 slidably disposed on the bore inner wall of the cylinder 141 and an impact bolt 145 that is slidably disposed on the tool holder 137 and transmits the kinetic energy of the striker 143 to the hammer bit 119. And the main constituent. The striker 143 corresponds to the “batter” in the present invention, and the impact bolt 145 corresponds to the “meson” in the present invention. The cylinder 141 has an air chamber 141 a that is partitioned by a piston 129 and a striker 143. The striker 143 is driven via the air spring of the air chamber 141a accompanying the sliding movement of the piston 129, and collides (hits) the impact bolt 145 slidably disposed on the tool holder 137. The hammering force 119 is transmitted to the hammer bit 119.

  The power transmission mechanism 117 meshes with the intermediate gear 132 that meshes and locks with the drive gear 121, the intermediate shaft 133 that rotates together with the intermediate gear 132, the small bevel gear 134 that rotates within the horizontal plane together with the intermediate shaft 133, and the small bevel gear 134. A large bevel gear 135 that engages and rotates in a vertical plane is mainly configured. The rotation output of the large bevel gear 135 is transmitted from the cylinder 141 spline-fitted to the large bevel gear 135 to the rotation sleeve 151 connected to the cylinder 141 via the connection pin 153, and further splined to the rotation sleeve 151. It is configured to be transmitted to the hammer bit 119 through the combined impact bolt 145 (see FIG. 5). The rotating sleeve 151 corresponds to the “power transmission member” in the present invention. The impact bolt 145 has a hexagonal hole 145a, and a rectangular shaft 119a formed at the base of the hammer bit 119 is inserted into the hexagonal hole 145a. As a result, the hammer bit 119 is rotationally driven together with the impact bolt 145.

  The rotary sleeve 151 has a rear end portion in the axial direction (piston 129 side) fitted to an outer peripheral portion of the front end portion in the axial direction (hammer bit 119 side) of the cylinder 153. Thereby, the cylinder 141 and the rotation sleeve 151 are connected concentrically. A connecting pin 153 for connecting and fixing the rotating sleeve 151 and the cylinder 141 is inserted from a through hole formed in the rotating sleeve 151 into a bottomed hole formed in the cylinder 141 from the outer diameter direction, and is connected to the outside of the rotating sleeve 151. The ring 155 is fitted to the ring 155 to prevent it from coming off. In the present embodiment, four connecting pins 153 are provided at intervals of 90 degrees in the circumferential direction of the fitting portion (see FIG. 6). Further, the cylinder 141 and the rotating sleeve 151 connected as described above are restricted from moving in the long axis direction with respect to the main body 103.

  In the hammer drill 101 configured as described above, when the driving motor 111 is energized and driven by the pulling operation of the trigger 109a by the user, the piston 129 is connected to the cylinder 141 via the motion conversion mechanism 113 mainly composed of a crank mechanism. The striker 143 linearly moves in the cylinder 141 due to a change in air pressure in the air chamber 141a of the cylinder 141, that is, an action of an air spring. The striker 143 collides with the impact bolt 145 to transmit the kinetic energy to the hammer bit 119.

  On the other hand, the rotation output of the drive motor 111 is transmitted to the cylinder 141 via the power transmission mechanism 117. As a result, the cylinder 141 is rotationally driven in the vertical plane, the rotational sleeve 151 connected and fixed by the cylinder 141 and the connection pin 153 is rotationally driven, and the impact bolt 145 that is further spline-fitted with the rotational sleeve 151. At the same time, the hammer bit 119 is rotated together. Thus, the hammer bit 119 performs the hammering operation in the axial direction and the drilling operation in the circumferential direction, and performs a drilling operation on the workpiece (concrete).

  The hammer drill 101 according to the present embodiment allows the hammer bit 119 to perform only the drill operation in addition to the working mode in the hammer drill mode in which the hammer bit 119 performs the hammer operation and the circumferential drill operation. Although it is possible to switch to the working mode in the drill mode or the working mode in the hammer mode in which the hammer bit 119 performs only the hammer operation, the mode switching mechanism is not directly related to the present invention. The description is omitted.

  The hammer drill 101 according to the present embodiment includes a blanking prevention mechanism 161 that prohibits the hammering operation of the hammer bit 119 when the drive motor 111 is energized and driven in a no-load state where the hammer bit 119 is not pushed backward. ing. FIG. 4 shows an enlarged view of the idle driving prevention mechanism 161. An air chamber 141 a that drives the striker 141 through the action of an air spring communicates with the outside through a breathing hole 141 b formed in the cylinder 141. The breathing hole 141b corresponds to the “communication portion” in the present invention. The idling prevention mechanism 161 is provided as a means for controlling the opening / closing of the breathing hole 141b. The idle driving prevention mechanism 161 is placed at an open position where the breathing hole 141b is opened and a slide ring 163 which is switched between a closed position where the breathing hole 141b is closed, and an open position where the slide ring 163 opens the breathing hole 141b. A pressure spring 165 that urges the slide ring 163 to the open position so that the slide ring 163 is opened is mainly used. The open position corresponds to the “open position” in the present invention, and the close position corresponds to the “close position” in the present invention. The slide ring 163 corresponds to the “valve member” in the present invention, and the pressure spring 165 corresponds to the “biasing member” in the present invention.

  The slide ring 163 is arranged in the outer peripheral region of the cylinder 141 and is movable in the hammer bit major axis direction. When the impact bolt 145 is pushed backward together with the hammer bit 119, the slide ring 163 is moved backward via the positioning ring 167 and the needle pin 169 that move backward together with the impact bolt 145, and closes the breathing hole 141b. It is supposed to be configured. The needle pin 169 corresponds to the “operation relay member” in the present invention. The pressure spring 165 is interposed between the slide ring 163 and a spring receiver 165a fixed to the outside of the cylinder 141, and biases the slide ring 163 forward to always open the breathing hole 141b. Hold (see FIG. 3). When the breathing hole 141b is open, the action of the air spring is disabled, and when the breathing hole 141b is closed, the action of the air spring is enabled.

  The positioning ring 167 is disposed outside the rear end side small diameter portion 145 c of the impact bolt 145, and is defined by the front moving end abutting on a stepped locking surface 151 a formed on the rotating sleeve 151. . The needle pin 169 is disposed between the positioning ring 167 and the slide ring 163, and is set to contact the positioning ring 167 and the slide ring 163 in the long axis direction (moving direction). Therefore, in an unloaded state where the hammer bit 119 is not pressed against the workpiece, the positioning ring 167 receives the biasing force of the pressure spring 165 that acts to hold the slide ring 163 in the open position, and the rotating sleeve 151. The abutment surface 151a is held in contact.

  The positioning ring 167 has a stepped shoulder between the large diameter portion 145b and the small diameter portion 145c of the impact bolt 145 when the hammer bit 119 is pressed against the workpiece and the impact bolt 145 is retracted together with the hammer bit 119. Press to move backward. The needle pin 169 is pushed backward by the positioning ring 167 that moves backward, and moves backward, and the slide ring 163 is pushed against the urging force of the pressure spring 165 to move to the closed position. In addition, the positioning ring 167 that moves backward has its rear end surface abutted against the front end surface of the cylinder 141 when the slide ring 163 is moved to a predetermined closed position, and the cylinder 141 receives a pushing force acting on the hammer bit 119. It is supposed to be configured. The cylinder 141 is restricted from relative movement in the long axis direction of the hammer bit with respect to the main body 103. For this reason, when the positioning ring 167 contacts the cylinder 141, the main body 103 is positioned with respect to the workpiece.

  The needle pin 169 is disposed in a state where the needle pin 169 is buried on the cylinder 141 side in the fitting region between the cylinder 141 and the rotating sleeve 151. The needle pin 169 is an elongated rod having a circular cross section, and is slidably received in a long groove 141c formed on the outer peripheral side of the cylinder 141 and extending in the long axis direction of the hammer bit. Is in contact with the rear end surface of the positioning ring 167 in a state where it protrudes a predetermined amount forward from the front end surface of the cylinder 141. The long groove 141c is formed in a substantially U-shaped cross section that opens on the outer diameter side. The cylinder 141 is formed so that its outer diameter is larger than the outer diameter of the area other than the fitting area in the fitting area where the cylinder 141 is fitted. Further, the needle pin 169 is configured so that the entirety of the needle pin 169 is accommodated in the long groove 141c in the fitting region of the cylinder 141 and does not protrude toward the inner diameter side of the rotating sleeve 151. Part of the outer diameter side of 141 protrudes to the outer side (outer diameter side) of the cylinder 141, and the rear end surface in the long axis direction of the protruding portion is in contact with the front end surface of the slide ring 163. In the present embodiment, four needle pins 169 are provided at intervals of 90 degrees in the circumferential direction of the cylinder 141 (see FIG. 6). In other words, the cylinders 141 and the rotary sleeve 151 are arranged at intermediate positions between the adjacent connection pins 153 so as not to interfere with the four connection pins 153 provided to connect the cylinder 141 and the rotation sleeve 151.

  Next, the operation of the hammer drill 101 configured as described above will be described. 2 and 4 show an unloaded state in which the hammer bit 119 is not pressed against the workpiece. In this no-load state, the slide ring 163 is pushed forward by the action of the pressure spring 165 of the idle driving prevention mechanism 161 and is placed in an open position where the breathing hole 141b is opened. In this state, the air chamber 141a communicates with the outside through the breathing hole 141b, and the action of the air spring is invalidated.

  On the other hand, when the user applies a forward pressing force to the main body 103 and the hammer bit 119 is pressed against the workpiece, the impact bolt 145 is moved backward along with the hammer bit 119 pushed back by the workpiece. It is pushed into the piston 129 side. As shown in FIGS. 1 and 3, the impact bolt 145 moved rearward contacts the positioning ring 151 and pushes the positioning ring 151 rearward. For this reason, the needle pin 169 moves backward together with the positioning ring 151, and the slide ring 163 moves backward against the urging force of the pressure spring 165. Thereby, the slide ring 163 closes the breathing hole 141b of the air chamber 141a, and the action of the air spring is made effective. Further, the positioning ring 151 pushed by the impact bolt 145 comes into contact with the front end surface of the cylinder 141. Thus, the pushing force acting on the hammer bit 119 is received by the cylinder 141 which is the main body 103 side member, whereby the main body 103 is positioned with respect to the workpiece.

  When the drive motor 111 is energized and driven, the drive gear 121 rotates in the horizontal plane by the rotation output. Then, the crank plate 125 rotates in the horizontal plane via the driven gear 123 engaged with and engaged with the drive gear 121, and thereby the piston 129 slides linearly in the cylinder 141 via the crank arm 127. The At this time, if the slide ring 163 is in an unloaded state where the slide ring 163 is placed at an open position where the breathing hole 141b is opened, the air in the air chamber 141a is discharged or sucked to the outside through the breathing hole 141b. There is no compression spring action. In other words, the hammer bit 119 is prevented from being emptied. On the other hand, in a load state where the slide ring 163 is placed at the closed position for closing the breathing hole 141b, the striker 143 moves linearly in the cylinder 141 through the action of the air spring of the air chamber 141a accompanying the sliding operation of the piston 129. The impact bolt 145 is collided (hit) and the kinetic energy is transmitted to the hammer bit 119. Thereby, the hammer bit 119 performs a hammering operation in the major axis direction, and performs a hammering operation on the workpiece.

  When the hammer drill 101 is driven in the hammer drill mode, the transmission gear 131, the transmission shaft 133, and the small bevel gear 134 that mesh with and engage with the drive gear 121 rotated by the rotation output of the drive motor 111 are integrated in a horizontal plane. It rotates. Then, the large bevel gear 135 that meshes with and engages with the small bevel gear 134 rotates in the vertical plane, and the tool holder 137 and the hammer bit 119 held by the tool holder 137 are rotated together with the large bevel gear 135. . Thus, when driven in the hammer drill mode, the hammer bit 119 performs a hammering operation in the major axis direction and a rotation operation in the circumferential direction to perform a hammer drill operation on the workpiece.

  In the present embodiment, a plurality of long grooves 141c extending in the long axis direction are formed on the outer diameter side of the cylinder 141 in the circumferential direction, and a needle pin that transmits the retreating operation of the hammer bit 119 to the slide ring 163 in the long grooves 141c. 169 is accommodated. As a result, the protrusion of the needle pin 169 to the outside of the cylinder 141 can be suppressed, so that the barrel portion of the gear housing 107 that accommodates the cylinder 141 can be prevented from spreading outward and can be made compact. A plurality of needle pins 169 are arranged at predetermined intervals in the circumferential direction of the cylinder 141. For this reason, the backward movement of the impact bolt 145 can be transmitted to the slide ring 163 in a well-balanced manner, and the smooth movement of the slide ring 163 can be maintained, and the thin portion in the circumferential direction of the cylinder 141 is partially Therefore, the strength reduction of the cylinder 141 can be reasonably suppressed.

  Further, according to the present embodiment, since the needle pin 169 is covered from the outside by the rotating sleeve 151 fitted to the front outer peripheral portion of the cylinder 141, the needle pin 169 can be operated stably and as a separate member It is not necessary to provide a cover member, and the number of parts can be reduced. Further, the needle pin 169 has a configuration in which the entirety of the needle pin 169 is buried in the cylinder 141 side, that is, a configuration in which the needle pin 169 does not protrude in the radial direction from the long groove 141c, so that the rotation of the rotating sleeve 151 in the outer diameter direction can be suppressed. In addition, it is not necessary to perform processing for forming a long groove on the inner diameter side of the rotary sleeve 151, and processing cost can be reduced.

  In the present embodiment, the rotation output of the cylinder 141 has been described in the case of the hammer drill 101 of a type in which the rotation output from the rotation sleeve 151 is transmitted to the hammer bit 119 via the impact bolt 145 that is spline-fitted with the rotation sleeve 151. The rotary output of the cylinder 141 may be applied to a hammer drill that is transmitted to the hammer bit 119 via the tool holder 137. In the present embodiment, the hammer drill 101 is described as an example of the impact tool. However, the hammer drill 119 is not limited to the hammer drill 101 and may be applied to an electric hammer in which the hammer bit 119 performs only a linear motion.

It is a sectional side view which shows the whole structure of the hammer drill which concerns on embodiment of this invention. It is a plane sectional view showing the whole composition of a hammer drill. It is a sectional side view which shows the principal part of a hammer drill. It is a sectional side view which expands and shows an idling prevention mechanism. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG.

Explanation of symbols

101 Hammer drill (blow tool)
103 Body (Tool body)
105 Motor housing 107 Gear housing 109 Grip 109a Trigger 111 Drive motor 113 Motion conversion mechanism 115 Stroke element 117 Power transmission mechanism 119 Hammer bit (tool bit)
119a Square shaft portion 121 Drive gear 123 Driven gear 125 Crank plate 127 Crank arm 129 Piston (driver)
132 Intermediate gear 133 Intermediate shaft 134 Small bevel gear 135 Large bevel gear 137 Tool holder 141 Cylinder 141a Air chamber 141b Breathing hole (communication portion)
141c long groove 143 striker
145 Impact bolt (meson)
145a Hexagonal hole 145b Large diameter portion 145c Rear small diameter portion 151 Rotating sleeve (power transmission member)
151a Locking surface 153 Connecting pin 155 Ring 161 Immersion prevention mechanism 163 Slide ring (valve member)
165 Pressure spring (biasing member)
165a Spring receiver 167 Positioning ring 169 Needle pin

Claims (3)

A tool body,
A tool bit that is arranged in the tip region of the tool body and performs a predetermined machining operation by linearly moving in the long axis direction;
A cylinder housed in the tool body,
A driver that performs linear motion in the long axis direction of the tool bit in the cylinder;
In the cylinder, a striking element that is linearly operated in the longitudinal direction of the tool bit via a pressure fluctuation of an air chamber in the cylinder accompanying a linear motion of the driver,
An intermediate element that is placed between the striker and the tool bit and transmits a linear motion of the striker to the tool bit;
A communication part for communicating the air chamber with the outside;
A valve member disposed outside the cylinder and movable between an open position for opening the communication portion and a closed position for closing the communication portion;
A biasing member that applies a biasing force to move the valve member to the open position;
When the tool bit is pressed against the workpiece, the tool bit is pushed and moved together with the tool bit and moved backward to the striker side, thereby resisting the biasing force of the biasing member. An operation relay member that moves the valve member to the closed position;
A plurality of the operation relay members are arranged at predetermined intervals in the outer circumferential direction of the cylinder, and at least a part thereof is buried in the cylinder. The impact tool according to claim 1,
The cylinder is configured to rotate around the long axis direction of the tool bit,
On the outside of the cylinder, there is further provided a power transmission member that transmits the rotation operation of the cylinder to the tool bit as a rotation operation around the long axis direction,
The power transmission member is fitted to the outer periphery of the cylinder in a state where relative movement around the tool bit long axis direction is restricted,
The impact tool, wherein the motion relay member is disposed between the cylinder and the power transmission member in a state of being buried in the cylinder. The impact tool according to claim 2,
A guide groove extending in the long axis direction of the tool bit is formed on the outer surface of the cylinder,
The impact tool characterized in that the motion relay member is movably accommodated in the guide groove without protruding from the outer surface of the cylinder in the outer diameter direction.

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