JPS63185506A - Hammer drill - Google Patents

Abstract

PURPOSE:To prevent unnecessary energy consumption and generation of noise by controlling the transmission of power between a motor and a motion transforming member through a clutch means, and by controlling the pressing of a drill bit coupled to a clutch plate by a mechanically associating means, against a surface to be drilled, with the use of an electromagnet solenoid. CONSTITUTION:During no drilling is made, a clutch plate 26 is positioned on the forward side so as to release the coupling between the plate 26 and a motion transforming member 5. A reduction gear 24 is meshed with a pinion 21, and therefore the rotation of the motor 2 is transmitted to a drill bit 8 through an intermediate shaft 23, a spindle 31 and a key 39. However, the member 5 is isolated so that a piston 4 is not reciprocated. When the bit 8 is made to abut against a surface to be drilled, a striker 33 is retracted to mesh the plate 26 with the member 5 so that the reciprocating motion of the piston 4 is transmitted to the bit 8 through the member 5, an striking member 41 and the striker 33. Thus, when no drilling is made, the piston 4 does not reciprocated so that unnecessary energy consumption may be reduced and the generation of noise may also be prevented.

Description

[Detailed description of the invention] 【Technical field】

The present invention relates to a hammer drill that applies not only rotation but also axial impact impact to the drill bit.

[Background technology]

There is a tool called a hammer drill as a tool for drilling holes in concrete. This is JP-A-57-10
As shown in Japanese Patent No. 2779, a piston that is reciprocated in the axial direction and a hammer that is also slidable in the axial direction are provided, and an air spring is interposed between the two to control the movement of the piston. The impact is transmitted to the impacting body via an air spring, and the impact impact is further applied to the drill bit which is rotationally driven by the impacting body. By the way, if the drill bit is operated without being pressed against the surface to be drilled, and impact impact is applied to the drill bit, in other words, if dry drilling occurs, damage to various parts will be accelerated. Usually, this type of tool is configured so that the striking body does not strike the drill bit when the drill bit is not pressed against the surface to be drilled to prevent dry striking, but the reciprocating drive of the piston Although damage caused by dry striking can be prevented because the impacting body reciprocates, it consumes a large amount of energy and generates noise even though the work is not actually being performed. It had some problems. Energy consumption is especially a big problem in devices that use batteries as a power source.

OBJECTS OF THE INVENTION The present invention has been made in view of the above points, and its purpose is to provide a hammer drill that consumes less energy.

[Disclosure of the invention]

Therefore, the present invention includes a motor, a spindle that is rotationally driven by the motor and holds a drill bit, and a spindle that is connected to the motor via a motion converting member to perform reciprocating motion and that is connected to the motor through an air spring and a striking body. In a hammer drill equipped with a piston that applies impact impact to the piston, the hammer drill is located between the motor and the motion converting member and generates the power to open the motor and the motion converting member in response to the pressing force of the drill bit against the surface to be drilled. It is characterized in that it includes a clutch means for controlling transmission, so that power is not transmitted to the piston until the drill bit is pressed against the surface to be drilled. The present invention will be described in detail below based on illustrated embodiments. First, the overall structure will be explained. As shown in FIG. 4, the main body housing 1 has a chuck part 13 at its front end into which a drill bit 8 is attached, and a handle part 16 extends from the lower part of the rear end. The storage battery pack 9 is detachably attached to the lower end of the handle portion 16. In the figure, 14 is a switch handle, 15 is a rotation direction switching handle,
Further, 12 is a motor mounting base, and 11 is a housing 7 that also serves as a gear case. As shown in FIG. 1, the motor 2 is housed in the rear part of the main body huffing 1 with its axis oriented in the front-rear direction, and a pinion 21 is fixed to its output shaft 20. This pinion 21 includes a housing 7 ring 11 and a motor mounting base 1.
2 and meshes with a reduction gear 24 press-fitted to one end of an intermediate shaft 23 whose both ends are rotatably supported via bearings 22, 22 and whose axial direction is parallel to the axial direction of the motor 2. Further, the intermediate shaft 23 has a pinion 25 at the other end.
is attached to be freely rotatable, a motion conversion member 5 is attached to one end side so as to be freely rotatable, and a clutch plate 26 splined to the intermediate shaft 23 is attached to the center part. There is. This clutch plate 26, which is slidable in the axial direction of the intermediate shaft 23, is provided with an engaging pawl 27 that engages with the motion converting member 5 on one end side, and an engaging pawl 28 that engages with the pinion 25 on the other end side. Nissin 2 on the outer circumferential surface.
It is equipped with 9. On the other hand, a spindle 31 rotatably supported by a bearing 30 is installed in the front end of the main body housing 1 . This spindle 31 has a gear 32 fixed to the outer peripheral surface of its rear end that engages with the pinion 25, and a striker 33 that is slidable in the axial direction. The key 39 constitutes the chuck 13 that holds the drill bit 8 so that it can freely slide within a predetermined range. Here, the striker 33 has its axial sliding range regulated by a locking body 34 fixed inside the spindle 31, and is interlocked with the striker 33 via a bearing 35 at its rear end. A bar 36 is attached. This interlocking lever 36 has its tip connected to the clutch plate 2.
It is engaged with a groove 29 provided in 6. On the other hand, a piston 4 and a striking body 41 are installed behind the striker 33. The piston 3 is held slidably in a direction parallel to the axial direction of the intermediate shaft 23 and the spindle 31 by a motor mount 12 to which the motor 2 is attached, and is connected to the motion conversion member 5. This piston 4, which has a cylindrical shape with a closed end and a closed rear end, has a striking body 31 slidably housed therein. The motion converting member 5 converts rotational motion into reciprocating motion, and as shown in FIG.
1, a pongee 53 protruding from the ring 52, and a slider slidable on the shaft 53 and connected at one end to the piston 4 by a piston pin 44. 54, the center of rotation of the ring 52 is inclined with respect to the axial direction of the intermediate shaft 23, and when the spherical body 50 rotates together with the intermediate shaft 23, the ring 52 protrudes from the ring 52. The shaft 53 swings, and as a result, the piston 4 is driven back and forth. However, in the lever hammer drill, when the tip of the drill bit 8 is not in contact with the surface to be drilled, the striker 33 and the interlocking lever 36 are in the forward position, as shown in FIG. 1, and the clutch plate 26 is moved forward. Due to the position, the clutch plate 26 and the spherical body 5 in the motion converting member 5
0 is in a disengaged state, and the clutch plate 2
6 and the pinion 24 are in an engaged state, so when the motor 2 is operated by operating the switch handle 14, the rotation of the motor 2 is transferred from the intermediate shaft 23 to the spindle 3.
1 and key 39 to the drill bit 8. However, since the motion converting member 5 is separated, the piston 4 does not reciprocate. In this state, if the tip of the drill bit 8 is pressed against the surface to be drilled, the long groove 8 provided on the drill bit 8
0 and the key 3c3 that engages with it, the drill bit 8 moves backward, as shown in FIG. 2, moving the striker 33 rearward. As a result, striker 3
3 through a bearing 35 moves the clutch plate 26, and in order to engage the clutch plate 26 with the motion converting member 5, the piston 4 is thereafter reciprocated through the motion converting member 5. The striking body 41 follows the reciprocating movement of the piston 4 via the air spring in the air chamber 42 inside the piston 4, and the striking body 41
When the person hits the striker 33, the impact impact is the striker 33.
is transmitted to the drill bit 8 through. Even in this state, the clutch plate 26 and the pinion 24 remain in mesh with each other, so the drill bit 8 continues to rotate. When the drilling operation is completed and the drill bit 8 is released from the surface to be drilled, the next time the striker 33 is struck by the striking body 41, the striker 33 moves forward and moves through the interlocking lever 36.
The clutch plate 26 and the motion converting member 5 are disengaged. Therefore, even if the motor 2 is rotated from now on, the drill bit 8 only rotates, and the piston 4 does not reciprocate. The connection between the clutch plate 26 and the motion converting member 5 is not limited to the above-mentioned dog clutch.
As shown in FIG. #IJ5, it may be configured as a friction clutch. However, it is preferable to increase the roughness of the friction contact surface to increase the torque transmission force. Other embodiments are shown in FIGS. 6 and 7. This is because the striker 33 is made of a permanent magnet and the striker 33 is made of a permanent magnet.
A sensor 6 for detecting magnetism is provided, and the clutch plate 26 is controlled by operating a solenoid 7 according to the output of the sensor 6, which is a Hall IC. The sensor 6 is supplied with a constant current and outputs a voltage corresponding to the detected magnetism, and this voltage is compared with a reference voltage of a reference voltage generation circuit 61 in a comparator 62 as shown in FIG. Then, the comparison output amplified by the amplifier 63 is used to operate the slide/id 7 via the relay 64. When the striker 33 retreats due to the drill bit 8 being pressed against the surface to be drilled, this is detected by the sensor 6.
detects this and activates the solenoid 7 to connect the clutch plate 26 and the motion converting member 5, and when the drill bit 8 is separated from the surface to be drilled and the striker 33 moves forward, the solenoid 7 provided in the solenoid 7 The clutch plate 26 is returned to its original position by the return spring 70, and the clutch plate 26 and the motion converting member 5 are separated.

【Effect of the invention】

As described above, in the present invention, when the motor is operated, the piston does not perform reciprocating motion unless the drill bit is pressed against the surface to be drilled, and the drill bit cannot be pressed against the surface to be drilled. The piston starts operating for the first time, and as a result, there is no unnecessary energy consumption and noise generation is suppressed, and the number of drilling operations per charge using a storage battery is reduced. This is particularly effective in cases where there are restrictions on

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views of one embodiment of the present invention, FIG. 3 is an exploded perspective view of the motion converting member of the same, FIG. 4 is a perspective view of the entire same, and FIG. 5 is a clutch. FIG. 6 is a longitudinal sectional view of another embodiment, and FIG. 7 is a block circuit diagram of the same example, in which 2 is a motor, 4 is a piston, 5 is a motion conversion member, 8 is a drill bit, 26 is a clutch plate, 31 is a spindle, and 41 is a striking body. Agent Patent Attorney Ishi 1) Chief 7 Figure 3 WS4 Figure 5

Claims (4)

[Claims] (1) A motor, a spindle that is rotationally driven by the motor and holds a drill bit, and a spindle that is connected to the motor via a motion conversion member to perform reciprocating motion and that strikes the piston via an air spring and a striking body. In a hammer drill equipped with a piston that applies an impact, the device is located between the motor and the motion converting member and controls power transmission between the motor and the motion converting member according to the pressing force of the drill bit against the surface to be drilled. A hammer drill characterized in that it is equipped with a clutch means for (2) Claim 1, characterized in that the clutch means is provided between the clutch plate and the motion converting member, and the clutch plate and the drill bit are connected by mechanical interlocking means. Hammer drill as described. (3) The hammer drill according to claim 2, wherein the clutch means provided between the clutch plate and the motion converting member is a friction clutch. (4) The clutch means is provided between the clutch plate and the motion converting member, and the clutch plate is controlled by a solenoid operated by a sensor output that electromagnetically detects the pressing of the drill bit against the surface to be drilled. The hammer drill according to claim 1, wherein the hammer drill is a hammer drill.