JPH01240208A - Hammer drill - Google Patents

Abstract

PURPOSE:To suppress the generation of noise by making a drill bit movable in the axial direction in a spindle, providing a striker between a striking body and the drill bit axially movably in the spindle, and linking the striker to the engaging/disengaging means of a clutch. CONSTITUTION:When the tip of a drill bit 8 is not applied on a machining face, a striker 33 is in an advanced position while a clutch 6 is in a disengaged condition being energized by a clutch shaft 60 by means of a spring. Hence, as a switch handle 14 is operated, the rotation of a motor 2 is transmitted to the drill bit 8 from an intermediate shaft 23 via a spindle 3. However, since a motion converting member 5 is being disconnected, the reciprocation of a piston 4 does not take place and only the drill bit 8 carries out rotation. In this condition, as the tip of the drill bit 8 is pressed against the machining face, the striker 33 is retracted engaging the clutch 6. The reciprocation of the piston 4 is followed by a striking body 41, which is transmitted to the bit 8 through the striker 33.

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.

[Prior Art 1] There is a tool called a hammer drill as a tool for drilling holes in concrete. This includes a striking means that is reciprocated in the axial direction and a hammer 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 striking body through the air spring. At the same time, the striking body further applies a striking impact to the drill bit that is rotationally driven. By the way, if a moon impact impact is applied to the drill bit even when the drill bit is not pressed against the iNi to be drilled, if dry striking occurs, damage to each part will be accelerated. Usually two of this kind [
In order to prevent blank firing, the drill bit 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. Since the reciprocating movement was still being performed, damage due to dry firing could be prevented, but even though no actual work was being performed,
This has the problems of high energy consumption and noise generation. In particular, energy consumption is a big problem in devices that use batteries as a power source. To this end, British Published Patent No. 2,170,746 shows the following. This is because a clutch is provided between the striking means and the motor, and when the drill bit is pushed toward the surface to be drilled, this clutch is engaged, and when the drill bit is released from the surface to be drilled, the clutch is disengaged and the impact is struck. The means are rendered inoperable. In other words, the spindle that holds the drill bit and transmits the rotational force from the motor to the drill pin is made to be able to slide freely in the axial direction, and the retraction of the spindle when the drill bit is pressed against the surface to be drilled is utilized. The above-mentioned clutch is connected, and the striking means for applying an impact to the drill bit is operated only when the drill bit is pushed onto the surface to be drilled. [Problems to be Solved by the Invention] However, in the structure described in item 1, since the spindle is movable in the axial direction, fine chips of concrete generated during drilling may enter the ff169 section. There is a risk that the life of the potato will deteriorate. 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]

Accordingly, the present invention comprises a motor, a spindle that is rotationally driven by the motor and holds the drill focus, and a spindle that is connected to the motor through a motion converting member to perform reciprocating motion and that is connected to the motor through an air spring and a striking body. A hammer drill includes a striking means that applies a striking impact to the piston, and a clutch that is located between the motor and the striking means and controls power transmission between the two. A striker is disposed within the spindle and is movable in the axial direction and is interposed between the striking body and the drill bit, and the striker is connected to the on/off means of the clutch. It is characterized by its presence. [Operation] According to the present invention, the clutch is disengaged and power is not transmitted to the striking means until the drill pin is pressed against the surface to be drilled.Secondly, the movement when the drill bit is pushed against the surface to be drilled In order to transmit the information to the clutch on/off means, a striker, which is disposed within the spindle and interposed between the striking body and the drill focus, is used instead of the spindle. [Examples] The present invention will be described in detail below on the basis of illustrated examples. First, to explain the overall structure, the main body housing 1 has its ti
ff A chunri part 13 to which the drill focus 8 is attached is arranged on the F4, and a handle part 16 extends from the lower part of the rear end, and the handle part] 6 is located below the center.
It is said that there is one removable battery Q bag 975C located in the place where the gravity is. In the figure, 14i and t switch handles, 15 a rotation direction switching handle, and 12 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 21 is fixed to its output shaft 20. The reduction gear 24 with which the binion 21 meshes has bearings 22 at both ends by the housing song 11 and the motor assembly 12.
．． The motor 2 is rotatably supported through the motor 22, and the axial direction is the motor 2.
The intermediate shaft 23 is press-fitted to one end of the intermediate shaft 23, which is parallel to the axial direction of the intermediate shaft 23. A motion converting member 5 is attached to one end of the intermediate shaft 23,
A binion 25 having a long dimension in the axial direction J is formed on the outer periphery m of the other end, and the outer periphery of the binion 25 has a cylindrical inner tooth It 6 that meshes with the binion 25 on the inner circumferential surface of one end.
] A 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. The clutch shaft 60 has an end portion on the motion conversion member 5 side.
A plurality of cutouts 62 are provided on the same part of the outer periphery of the 7-run outer periphery 3 as shown in FIG.
A clutch plate 65 placed on the clutch shaft 60 is provided with a plurality of clutch pawls 〇〇 that are passed through the notches 62 of the clutch shaft 60 and whose tips protrude toward the motion conversion member 5 side beyond the clutch shaft 60. ing. A spring 64 is disposed between the motion conversion member 5 and the clutch shaft 60, and a retaining ring 6 is provided on the clutch shaft 60.
A spring 67 is disposed between the clutch plate 65 and the spring seat 69, and these springs 64 and 67 bias the clutch plate 65 toward the motion converting member 5, and the clutch shaft 60 is rotated in the opposite direction. biased in the direction. 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 peripheral surface of its rear end so that it can slide freely in the axial direction with a key 38, and a striker 33 is installed inside the gear 32 so that it can freely slide in the axial direction. The tip is a drill bit 8.
It constitutes a member of the chuck 13 that holds the holder so that it can freely slide within a predetermined range. In the figure, 39 is a mounting groove for the key 38. 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 rear end portion having a small diameter has a locking body 34 fixed inside the spindle 3. It is covered with a cup-shaped pusher 35 housed within the end. This pusher 35 is
Axial slint 3 formed at the rear end of the spindle 3
A protrusion 36 is provided that protrudes outward from 7 and contacts the surface of the gear 32 on the drill bit 8 side. 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 a motor mounting base 12 to which the motor 2 is attached.
It is held slidably in a direction parallel to the axial direction of the intermediate shaft 23 and the spindle 3 by a part of the sill formed on the shaft, and the rear end side connected to the motion converting member 5 is closed. It has become a thing. 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, and a plurality of balls 51 on the outer circumferential surface of this cylindrical body 50 so as to freely rotate. A hollow ring 52 and a shaft 5 protruding from the ring 52
3, and a slider 5 which is slidable on the shaft 53 and whose one end is connected to the piston 4 by a piston pin 44.
4, the center axis of rotation of the ring 52 is inclined with respect to the axial direction of the intermediate shaft 23, and when the cylindrical 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
A reciprocating drive is performed. As described above, the gear 32 provided on the spindle 3 meshes with the binion 25 on the intermediate shaft 23, and the end face of the clutch shaft 60, which is biased by the spring 64, is attached to the thrust plate 27. are in contact through Further, the intermediate shaft 23 in the motion converting member 5
The clutch shaft 6o of the cylindrical body 50 is freely rotatably attached to the
A concave groove 56 is formed on the side end surface, into which a clutch pawl 66 protruding from the clutch plate 65 engages. When the clutch pawl 66 is not engaged with the concave groove 56, the motion converting member 5 and the piston 4 are separated from the motor 2, but when the clutch pawl 66 is engaged with the concave groove 56, the motor 2 is disconnected. 2 is transmitted to the piston 4 via the motion conversion member 5. The clutch 6 is formed between the clutch plate 65 and the motion conversion member 5. 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. The detachment lever 70 is rotatably attached to the main body housing song 1, and has a pin 71 protruding from an eccentric position on the distal end surface, and a roller 72 that is in contact with the end surface of the clutch plate 65 on the motion conversion member 5 side. is freely rotatably supported by the bin 71. However, with this hammer drill, when the tip of the trilby point 8 is applied to the surface to be drilled, sometimes the force of the striker 33 is lowered as shown in Figures 1 and 2. In the forward position, 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 actuated by rotating the spindle 14, the rotation of the motor 2 is transmitted from the intermediate shaft 23 to the trilby unit 8 via the spindle 3, but the motion converting member 5 is disconnected. Because of this, 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 move against the spindle 3 within the permissible range ν, as shown in FIGS. 5 and 6. Move backward and push the striker 33 backward. This striker 33 retreats.
5 moves the gear 32 backward and moves the gear 32 backward.
Clutch shaft 6 attached to intermediate shaft 23 via
0 against the spring 64 and push it toward the -C motion converting member 5 side. 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 screw 1 is reciprocated through the motion conversion member 5, and the reciprocating movement of the piston 4 causes the impact body 41 to move through the air splash between the inner bottom surface of the piston 4 and the impact body 41. The striking impact when the striking body 41 strikes the striker 33 is transmitted to the drill focus 8 through the striker 33. When the drilling work is completed and the drill hit 8 is released from the surface to be drilled, the clutch shaft 60 moves against the motion converting member 5 ζ, M due to the force τj of the spring 64, and the clutch pawl 66 of the clutch plate 65 is recessed. It is pulled out from the groove 56, the clutch 6 is disengaged, and the gear 32, butcher 35, striker 33, and drill bit 8 also return to their initial positions. Therefore, the drill focus 8 is in a state where it only rotates. When drilling into iron plates or wood does not require striking, as in the case of drilling work, by rotating the release lever 70, the clutch plate 65 can be moved toward the motion converting member 5 side, as shown in Figure J17. may be closed with rollers 72. In the above embodiment, the pusher 35 and the gear 32 are interposed between the striker 33 and the clutch shaft 60, which is the on/off means for the clutch 6. However, in the embodiment shown in FIG. It is fixed to the spindle 3, and the clutch shaft 60 is directly moved by the pusher 35. 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. [Effects of the Invention] As described above, in the present invention, even when the motor is operated, the striking means does not perform reciprocating motion when the drill bit is not pressed against the surface to be drilled, and the impact means does not move back and forth when the drill bit is not pressed against the surface to be drilled. The operation of the striking means begins only when the drill bit is pressed against it, and for this reason, there is no unnecessary consumption of energy and the generation of noise is suppressed. In order to transmit the force applied to the surface to be drilled to the on/off means of the clutch, the spindle that holds the drill bit (in this spindle, an axially slidable member is disposed to freely move the drill bit and the striking body and the trill bit are connected to each other). Since a striker is used between the spindle and the spindle, it is only necessary to allow the spindle to rotate freely, and there is no intrusion of fine concrete powder into the mechanism that would be caused by making the spindle freely movable in the axial direction. You can get something highly reliable with a long lifespan.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of the present invention-embodiment; Fig. 2 is a longitudinal cross-sectional view of the same clutch; Fig. 3 is a perspective view of the clutch shaft and clutch plate; Fig. 4 is a cross-sectional view of the same; Figure 5 and l
156 is a longitudinal sectional view when the clutch is connected, FIG. 7 is a sectional view when the clutch is forcibly disengaged, and FIG. 8 is a longitudinal sectional view of another embodiment, where 2 is the motor, 3 is the spindle, and 4 is the A piston, 5 a motion converting member, 6 a flanch, 8 a trilbyte, 41 a striking body, 60 a clutch shaft, and 65 a flange 41. Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[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 strikes the piston via an air spring and a striking body. In a hammer drill equipped with a striking means for applying an impact and a clutch located between a motor and the striking means to control power transmission between the two, the drill bit is freely movable in the axial direction with respect to the spindle. 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 the striker is connected to the on/off means of the clutch. hammer drill.