JPH0431801B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a hammer drill in which not only rotation but also axial impact impact can be applied to the drill bit.

[Conventional technology]

As a tool for drilling holes in concrete,
There is something called a hammer drill. This includes a striking means that is reciprocated in the axial direction and a striking body that is also slidable in the axial direction, and an air spring is interposed between the two, so that the movement of the striking means is controlled by the air spring. In addition to transmitting the impact to the body, the impact impact is further applied to the drill bit which is rotationally driven by the impact body. By the way, if impact impact is applied to the drill bit even when the drill bit is operated without being pressed against the surface to be drilled, in other words, if dry drilling occurs, damage to various parts will be accelerated, so normally This type of tool is constructed so that the striking body does not strike the drill bit when the drill bit is not pressed against the surface to be drilled, in order to prevent dry striking, but the reciprocating drive of the striking means and the striking body Since the reciprocating motion of the machine was still being performed, damage caused by blank firing could be prevented, but it still had the problem of consuming a large amount of energy and generating noise even though the work was not actually being performed. Was. Energy consumption is especially a big problem in devices that use batteries as a power source. To this end, British Published Patent No. 2170746 shows the following. This is because a clutch is provided between the striking means and the motor, and when the drill bit is pressed against the surface to be drilled, this clutch is connected, and when the drill bit is removed from the surface to be drilled, the clutch is disengaged and the striking means no longer operates. That's what I do. In other words, the spindle that holds the drill bit and transmits the rotational force from the motor to the drill bit is made slidable in the axial direction, and the retraction of the spindle when the drill bit is pressed against the surface to be drilled is utilized to create the The clutch is connected so that the striking means for applying a striking impact to the drill bit is activated only when the drill bit is pressed against the surface to be drilled.

[Problem to be solved by the invention]

However, with the above structure, since the spindle is movable in the axial direction, there is a risk that fine cuttings of the concrete generated during drilling may enter the mechanism, leading to a deterioration of the service life. The present invention has been made in view of these points, and its purpose is to automatically disconnect the striking means from the motor when the striking operation is not required, thereby reducing energy consumption, and to achieve the above-mentioned automatic operation. To provide a hammer drill in which a structure for separating does not cause chips to enter into a mechanism part.

[Means to solve the problem]

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 strikes the drill bit via a striking body. A hammer drill equipped with a striking means for applying an impact and a clutch positioned between a motor and a motion converting member to control power transmission between the two, the drill bit being freely movable in the axial direction relative to the spindle, A striker which is movable in the axial direction and is interposed between the striking body and the drill bit is disposed inside the drill bit, and a pusher for driving the on/off means of the clutch is connected to the striker. have.

[Effect]

According to the present invention, the clutch is in a disengaged state and no power is transmitted to the striking means until the drill bit is pressed against the surface to be drilled, and the movement when the drill bit is pressed against the surface to be drilled is is not transmitted to the clutch's on/off means via the spindle, but via a striker disposed within the spindle and interposed between the striking body and the drill bit.

【Example】

The present invention will be described in detail below based on illustrated embodiments. First, to explain the overall structure, the main body housing 1 has a chuck part 13 on the front end into which the drill bit 8 is fitted, a handle part 16 extending from the lower part of the rear end, and a handle part 16 extending from the lower part of the center part. On the other hand, a storage battery pack 9 is removably located in front of the handle portion 16. 14 in the diagram
15 is a switch handle, 15 is a rotation direction switching handle, and 12 is a motor mounting base. As shown in FIG. 1, the motor 2 is housed in the rear part of the main body housing 1 with its axial direction being the front-rear direction, and a pinion 2 is attached to the output shaft 20 of the motor 2.
1 is fixed. And this pinion 21
is press-fitted onto one end of an intermediate shaft 23 which is rotatably supported by the housing 11 and the motor mounting base 12 via bearings 22, 22, and whose axial direction is parallel to the axial direction of the motor 2. Intermediate shaft 2
It meshes with a reduction gear 24 press-fitted into one end of 3. The intermediate shaft 23 has a motion conversion member 5 attached to one end, and a pinion 25 having a long axial dimension on the outer peripheral surface of the other end. Pinion 25 on the surface
A clutch shaft 60 equipped with an internal gear 61 that meshes with the clutch shaft 60 is disposed so as to be slidable in the axial direction, and a cylindrical clutch plate 65 is also disposed on the outer periphery of the clutch shaft 60 so as to be slidable in the axial direction. ing. The clutch shaft 60 is provided with a flange 63 at its end on the motion converting member 5 side, as well as a plurality of notches 62 cut out from the outer circumference of the flange 63 as shown in FIG. The covered clutch plate 65 is passed through the notch 62 of the clutch shaft 60 and its tip is inserted into the clutch shaft 60.
A plurality of clutch pawls 66 are provided that protrude toward the motion converting member 5 side. A spring 64 is disposed between the motion converting member 5 and the clutch shaft 60, and a retaining ring 68 and a spring seat 69 provided on the clutch shaft 60 and the clutch plate 6
A spring 67 is disposed between the clutch plate 65 and the movement converting member 5, and these springs 64 and 67 bias the clutch plate 65 toward the motion converting member 5, and bias the clutch shaft 60 in the opposite direction. There is. On the other hand, a spindle 3 rotatably supported by a bearing 30 is installed in a front end portion of the main body housing 1 which also serves as a gear case. This spindle 3 has a gear 32 that engages with the pinion 25 attached to the outer circumferential surface of the rear end thereof so as to be slidable in the axial direction by a key 38.
A striker 33 is disposed inside so as to be slidable in the axial direction, and its tip constitutes a member of a chuck 13 that holds the drill bit 8 so as to be slidable within a predetermined range. 39 in the diagram is key 3
8. This is the mounting groove. Here, the striker 33 has its sliding range in the axial direction restricted by a locking body 34 fixed inside the spindle 3, and the small-diameter rear end of the striker 33 has a locking body 34 fixed inside the spindle 3. A cup-shaped pusher 35 housed in the rear end portion is covered with an elastic body 73 such as an O-ring, and the elastic body 73 is positioned between the striker 33 and the pusher 35 in the axial direction. There is. The pusher 35 protrudes outward from an axial slit 37 formed at the rear end of the spindle 3, and extends through the gear 3.
A protrusion 36 is provided which contacts the surface of the second drill bit 8. On the other hand, behind the striker 33, a piston 4 having a cylindrical shape with a bottom as a striking means, and a striking body 41 slidably disposed within the piston 4 are installed. The piston 4 is held slidably in a direction parallel to the axial direction of the intermediate shaft 23 and the spindle 3 by a cylinder portion formed on the motor mount 12 to which the motor 2 is attached, and the piston 4 is held slidably in a direction parallel to the axial direction of the intermediate shaft 23 and the spindle 3. The rear end side connected to the conversion member 5 is closed. The motion converting member 5 converts rotational motion into reciprocating motion, and includes a cylindrical body 50 into which the intermediate shaft 23 is inserted;
A ring 52 is freely rotatably attached to the outer peripheral surface of the cylinder 50 via a plurality of balls 51, a shaft 53 projects from the ring 52, and one end is slidable relative to the shaft 53. The ring 52 is composed of a slider 54 connected to the piston 4 by a piston pin 44, and the center axis of rotation of the ring 52 is inclined with respect to the axial direction of the intermediate shaft 23. When the body 50 rotates, the shaft 53 protruding from the ring 52 swings,
As a result, the piston 4 is driven back and forth. A gear 32 provided on the spindle 3
As mentioned above, is engaged with the pinion 25 on the intermediate shaft 23, and has a spring 6 on its side.
The end surfaces of the clutch shaft 60 biased by the clutch shaft 4 are in contact with each other via the thrust plate 27. Further, on the end surface of the cylinder 50 on the clutch shaft 60 side, which is rotatably attached to the intermediate shaft 23 of the motion converting member 5, there is a groove 56 in which a clutch pawl 66 protruding from the clutch plate 65 engages. is formed. When the clutch pawl 66 is not engaged with the groove 56, the motion converting member 5 and the piston 4 are connected to the motor 2.
Although the clutch pawl 66 is separated from the concave groove 56, the rotation of the motor 2 is transmitted to the piston 4 via the motion converting member 5. A clutch 6 is provided between the clutch plate 65 and the motion converting member 5.
is being formed. Furthermore, a disconnection lever 70 is provided on the side surface of the main body housing 1 to forcibly prevent the clutch 6 from being connected. Main body housing 1
The detachment lever 70 is rotatably attached to the lever 70, and has a pin 71 protruding from an eccentric position on the distal end surface, and a roller 72 in contact with the end surface of the clutch plate 65 on the motion conversion member 5 side.
It is freely rotatably supported by a pin 71. However, with this lever hammer drill, when the tip of the drill bit 8 is not in contact with the surface to be drilled, the first
As shown in the drawings and FIG. 2, the striker 33 is in the advanced position, and the clutch 6 is in a disengaged state due to the bias of the clutch shaft 60 by the spring 64. Therefore, when the motor 2 is operated by operating the switch handle 14, the rotation of the motor 2 is transmitted from the intermediate shaft 23 to the drill bit 8 via the spindle 3, but since the motion conversion member 5 is separated, In other words, the piston 4 does not reciprocate, and the drill bit 8 only rotates. In this state, if the tip of the drill bit 8 is pressed against the surface to be drilled, the drill bit 8 will retreat relative to the spindle 3 within the permissible range, as shown in FIGS. 5 and 6, and the striker will move back. 3
Push 3 backwards to make it move backwards. The striker 33 includes an elastic body 73 and a pusher 35.
The gear 32 is moved rearward through the clutch shaft 23, and the gear 32 pushes the clutch shaft 60 attached to the intermediate shaft 23 toward the motion converting member 5 against the spring 64. As a result, the clutch pawl 66 of the clutch plate 65 engages with the groove 56 in the motion converting member 5 while being biased by the spring 67, thereby connecting the clutch 6. Thereafter, the piston 4 reciprocates through the motion converting member 5, and the striking body 41 follows the reciprocating motion of the piston 4 via the air spring between the inner bottom surface of the piston 4 and the striking body 41. The impact impact when the striking body 41 strikes the striker 33 is transmitted to the drill bit 8 through the striker 33. The reaction force generated when the striker 33 applies a striking impact to the drill bit 8 is absorbed by the elastic body 73 disposed between the striker 33 and the pusher 35, and the clutch claw 66 of the clutch 6 is pushed by the spring 67. Since the clutch 6 is engaged with the motion converting member 5 side in this state, the connected state of the clutch 6 will not become unstable due to the above-mentioned reaction force. Further, since the elastic body 73 is interposed, no sound is generated due to vibration between the striker 33 and the pusher 35. When the drilling operation is completed and the drill bit 8 is released from the surface to be drilled, the clutch shaft 60 is moved away from the motion converting member 5 by the force of the spring 64, and the clutch pawl 66 of the clutch plate 65 comes out of the groove 56. When the clutch 6 is released, the gear 32, pusher 35, striker 33 and drill bit 8 also return to their initial positions. Therefore, the drill bit 8 is in a state where it only rotates. When there is no need to use impact, such as when drilling holes in iron plates or wood, by rotating the release lever 70, the movement converting member 5 side of the clutch plate 65 can be removed as shown in FIG. The roller 72 may be used to prevent this movement. In the above embodiment, the striker 33 and the clutch 6
In the embodiment shown in FIG. 8, the gear 32 is fixed to the spindle 3, and the pusher 35 and the clutch shaft 60, which is the on/off means, are interposed. It directly moves the clutch shaft 60. In FIG. 8, the upper side of the axis of the intermediate shaft 23 and the lower side of the axis of the spindle 3 are in the state where the clutch 6 is disengaged, and the lower side of the axis of the intermediate shaft 23 and the upper side of the axis of the spindle 3 are the state in which the clutch 6 is disconnected. This shows the connected state.

【Effect of the invention】

As described above, in the present invention, even if the motor is operated, the striking means 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. Only then does the operation of the striking means begin, and for this reason, there is no unnecessary consumption of energy, noise generation is suppressed, and moreover, the drill bit is pressed against the surface to be drilled. In order to transmit this information to the clutch's on/off means, a striker is connected to the striker, which is disposed to freely slide in the axial direction within the spindle and is interposed between the striking body and the drill bit, rather than the spindle that holds the drill bit. Because the spindle is made of a pusher, the spindle only needs to be rotatable, and there is no intrusion of fine concrete powder into the mechanism, which is caused by making the spindle freely movable in the axial direction, resulting in long life and reliability. You can get something of high quality. In addition, in the case where an elastic body is interposed between the striker and the pusher for driving the clutch on/off means, the elastic body buffers the reaction force when the striking means applies a striking impact to the drill bit via the striker. In order to prevent the above-mentioned reaction force from acting directly on the on/off means side of the clutch, the connection state of the clutch will not become unstable or abnormal noise will not occur.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the same clutch, Fig. 3 is a perspective view of the clutch shaft and clutch plate, and Fig. 4 is a cross sectional view of the same. , FIG. 5 and FIG. 6 are longitudinal cross-sectional views when the clutch is connected, FIG. 7 is a cross-sectional view when the clutch is forcibly disengaged, and FIG. 8 is a vertical cross-sectional view of another embodiment, wherein 2 is a motor; 3 is the spindle, 4 is the piston,
5 is a motion conversion member, 6 is a clutch, 8 is a drill bit, 33 is a striker, 35 is a pusher, 4
1 is a striking body, 60 is a clutch shaft, 65 is a clutch plate, and 73 is an elastic body.

Claims (1)

[Scope of 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 converting member to perform reciprocating motion and that drives the drill bit via a striking body. A hammer drill is provided with a striking means for applying a striking impact, and a clutch located between a motor and a motion converting member to control power transmission between the two, in which the drill bit is freely movable in the axial direction with respect to the spindle, and the above-mentioned A striker is disposed within the spindle and is movable in the axial direction and interposed between the striking body and the drill bit, and a pusher for driving the on/off means of the clutch is connected to the striker. Features a hammer drill. 2. The hammer drill according to claim 1, wherein an elastic body is interposed between the striker and the pusher.