JPH01274912A - Hammer drill - Google Patents

Abstract

PURPOSE:To prevent the fracture and damage of a clutch by providing a clutch bush slidable in an axial direction due to the pressing force of a drill bit to a drilling surface, and a spring member for transmitting the slide motion to the clutch for the connection thereof. CONSTITUTION:When the tip of a drill bit 8 is pressed to a drilling surface, a clutch bush 35 and a clutch shaft 60 are moved directly on the retreat of the bit 8 and a clutch disc 65 shifts to the side of a motion conversion member 5 in a state energized with a pressing spring 76. Furthermore, a steel ball 61 shifts inwardly and a cylindrical body 50 is connected to an intermediate shaft 23. Consequently, the clutch disc 65 for connecting a clutch 6 is effectuated with the motion of the clutch shaft 60 energized with a pressing spring 76. According to the aforesaid construction, even when the drill bit 8 is made in sudden contact with the drilling surface, an impact generated thereby is cushioned with the spring 76 and not transmitted to the clutch disc 65. Also, even if the aforesaid impact is extremely large, a force transmitted to the clutch disc 65 is restricted with the spring 76.

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]

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 striking body that is also slidable in the axial direction, and an air spring is interposed between the two.
The movement of the striking means is transmitted to the striking body via an air spring, and a striking impact is further applied to the drill bit rotationally driven by the striking 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, in order to prevent dry striking. The reciprocating motion of the driving and striking body 1j is still the same! - Although it is possible to prevent damage due to dry firing because it was not 4C, even though no work was actually done,
It has the following problems: it consumes a lot of energy and generates noise. In particular, energy consumption is a serious problem in devices that use batteries as a power source. For this purpose, the system shown in FIGS. 7 and 8 1:O has been proposed, in which the gear 24 at one end of the intermediate shaft 23 is engaged with the pinion 21 provided on the output shaft 20 of the motor. The pinion 25 at the other end of the shaft 23 is meshed with the gear 32 attached to the spindle 3, so that rotation is transmitted to the drill bit 8 via the spindle 3, and the striking body 41 is slidably connected to the drill bit 8. A motion conversion member 5 for converting rotational motion into reciprocating motion is connected to one end of the bottom cylindrical screw ln 4.
A clutch 6, which is a Tasaku clutch, is provided between the gear 24 and the gear 24.
It has been established. Normally, since the clutch 6 is disengaged, only 1.1 rotation is transmitted to the drill bit 8, but when the drill bit 8 is pressed against the jtL drilling surface and attached, the drill bit 8 is transferred together with the input spindle 3. A series of connecting plates 81 that move backward and are connected to a connecting plate 80 provided on the spindle 3 constitute one member of the clutch 6! ! [+V exchange member 5 is pressed to connect clutch 6, and thereafter, the cylinder 50 which is freely rotatably attached to the intermediate shaft 23 and which is freely rotatable with respect to this cylinder 50 and whose center of rotation is connected. A ring 52 whose ring is inclined with respect to the intermediate shaft 23, and a ring 5.
A pongee 53 is slidably inserted into a piston pin 49 that protrudes from the piston pin 49 and is rotatably provided on the rear light of the piston 4.
The motion converting member 5 consisting of the above causes the piston 4 to reciprocate, whereby the striking body 41 applies a striking impact to the trilby belt 8 through the striker 33. Then, when the drill and the foot 8 are separated from the surface to be drilled, the clutch 6 is disengaged and the drill bit 8 is again in a state where it only rotates. In other words, hit drill bit 8! The action of giving five blows is
This is done only when the drill bit 8 is pressed against the surface to be drilled, and Ritako's can also be used for work that does not require striking, such as drilling into wood. In order to achieve this, as shown in FIG. 9, a strike γ puff 4 is provided which comes into contact with the connecting plate 80 as the working lever 70 rotates to restrict the retreat of the long binder 3. Even when the drill bit 8 is pressed against the surface to be drilled, the spindle 3 does not move back, so that a state can be obtained in which the clutch 6 is not connected and only rotates.

Problem 1 to be Solved by the Invention Incidentally, in the conventional example described above, the member that receives the pressing force of the drill bit 8 against the surface to be drilled and transmits this to the clutch 6 is connected to the spindle 3 which moves backward together with the drill bit 8. and the cylindrical body 50 of the motion converting member 5, which is also one member of the clutch 6.
If the attaching operation is performed suddenly, the WE impact generated at this time will also act on the clutch, and there is a risk of breaking or damaging the clutch. The present invention has been developed in view of these points, and its purpose is to prevent the clutch from pressing against the drill bit even if the drill bit is suddenly pressed against the surface to be drilled, or even if the author applies his/her weight to the drill bit. To provide a hammer drill which is not subjected to time impact or load and which does not cause destruction or damage to a clutch. [Means for Solving the Problems] The present invention includes a motor, a spindle that is rotationally driven by the motor and holds a trillbit, and a spindle that is connected to the motor via a motion converting member to perform reciprocating motion. A hammer drill that is equipped with a striking means that simultaneously applies a striking impact to a drill bit via an air spring and a striking body, and a clutch that is located between a motor and a motion converting member and controls power transmission between the two. 1. A clutch push that slides in the ring direction of the v1 full bit in response to the pressing force of the drill bit against the surface to be drilled; - a spring member (11

[It is characterized by being -. 1 Effect] According to the present invention, the pressing force when pressing the drill bit against the surface to be drilled is transmitted from the clutch push to the clutch via the spring material, and the impact force is absorbed by the spring material. Furthermore, the maximum load applied to the clutch is regulated by the spring force of the spring material. [Example 1] The present invention will be described in detail below based on illustrated embodiments. First, to explain the overall structure, as shown in FIG. 4, the main body housing 1 has a chuck part 13 on its front end to which a drill bit 8 is attached, and a handle part 16 extends from the lower rear end. The storage battery pack 9 is extended and is detachably attached to a position below the center and in front of the handle part 16.14 in the figure is a switch handle, 15
is a rotation direction switching handle. The motor 2 is housed in the rear part of the main body housing 1 with its axial direction being the front-back direction, and a pinion 21 is fixed to the output wheel 20 of the motor 2, as shown in FIG. The gear 24 with which the pinion 21 meshes has bearings 22 and 22 at both ends, which are connected to the housing 11 and the motor mounting base 12.
The intermediate shaft 23 is press-fitted and fixed to one end of the intermediate shaft 23 which is rotatably supported through the motor 2 and whose ring direction is parallel to the axial direction of the motor 2 . The intermediate shaft 23 has a motion conversion member 5 attached to the gear 24@, and a pinion 25 formed on the outer circumferential surface of the other end, and a clutch described later is provided on the outer circumference between the pinion 25 and the motion conversion member 5. 6 are arranged. A spindle 3 rotatably supported by a bearing 30 is located in the front end of the main body housing 1 which also serves as a gear case.
is installed. This spindle 3 has a key 3 having a gear 32 that engages with the pinion 25 on the outer peripheral surface of the rear end.
8 and a retaining ring 39, a striker 33 is disposed inside so as to be slidable in the axial direction, and the tip part allows the drill bit 8 to slide freely within a predetermined range. It constitutes one member of the chuck 13 that holds it in place. 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. A cup-shaped cod 7 chipper 35 housed in the end portion is covered with an elastic body 37 such as an O-ring, and the elastic body 37 is positioned between the spindle 3 and the clutch pusher 35 in the axial direction. ing. The clutch push 35 includes a protrusion 36 that protrudes from the rear end opening of the spindle 3. 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 part of the shaft formed on the motor mounting base 12 to which the motor 2 is attached. The rear end side connected to the motion converting member 5 is closed. The motion conversion member 5 converts rotational motion into reciprocating motion, and is attached to a cylindrical body 50 into which the intermediate shaft 23 is inserted, and to the outer peripheral surface of this cylindrical body 50 via a number of poles 51 so as to be freely rotatable. ring 52 and pongee 5 protruding from the ring 52
3, a universal joint 54 into which a pongee 53 is slidably inserted, and whose spherical outer surface is rotatably connected to the rear end of the piston 4 via a joint receiver 55; A joint spring 56 is attached to the shaft 53 and biases the universal joint 54 toward the joint receiver 55. The piston 4 is located within an axially long long groove 42 of the piston 4. The ring 52 in the motion converting member 5 has its rotation center axis inclined with respect to the axial direction of the intermediate shaft 23, so that when the cylinder body 50 rotates together with the intermediate shaft 23, the ring 52 moves away from the ring 52. Since the rotation of the protruding pongee 53 around the intermediate shaft 23 is restricted from the piston 4 side, the protruding pongee 53 has an i
; As a result, the piston 4
A reciprocating drive is performed. Next, with respect to the intermediate wheel 23, the importance of rotation transmission between the rotatable motion converting member 50 and the intermediate wheel 2:3 will be explained. The clutch 6 includes a cylindrical clutch shaft 60 disposed on the outer periphery of a portion Nl (between the binion 25 and the motion conversion member 5) in the intermediate wheel 23, and a cylindrical clutch shaft 60 disposed on the outer periphery of the clutch shaft 60. Clutch plate 65 and cylinder body 5 of motion conversion member 5
) and a steel ball 61 that connects to the intermediate ring 23. The clutch shaft 61 is slidable in the axial direction with respect to the intermediate wheel 23, and a last plate 62 and a spring receiver 63 are attached to the pinion 25 side.
A protrusion 64 is formed on the outer peripheral surface of the other end, and the intermediate ring 23
A return spring 7:3 disposed between the retaining ring 26 and the retaining ring 26 is biased toward the pinion 25 side. Clutch plate 65 beam/Fuchi Yuzu 61 and more Tsumugi no j
It is capable of sliding in the opposite direction, and has a protrusion 66 that engages with the protrusion 64 of the clutch shaft 61 on the inner circumferential surface at one end, seven flange 67 on the outer circumferential surface, and a cylindrical body 50. A retraction portion 68 with a larger inner diameter is provided on the inner circumferential surface of the other end, and is biased toward the motion converting member 5 by a pressing spring 76 disposed between the spring receiver 63 and the spring receiver 63. - (The steel balls 61 are arranged in a plurality of holding holes 57 shaped like f& at the end of the cylinder body 50 located between the inner peripheral surface of the clutch plate 65 and the intermediate wheel 23. The diameter of the steel ball 61 is larger than the wall thickness at the end of the cylinder body 50.A steel ball 61 is placed on the outer peripheral surface of the intermediate ring 23 by being pushed by the clutch plate 65. A plurality of retaining parts 27 are provided with which the steel ball 61 engages when the center #1 of the drill bit 8 moves.However, in the lever hammer drill, when the tip of the drill bit 8 is not in contact with the surface to be drilled, As shown in Fig. 1, the stopper 33 is in the advanced position.At this time, the clutch shaft 60 and the clutch plate 65 are rotated due to the large inner diameter of the clutch 65. Since the retraction portion 68 is located on the outer periphery of the steel ball 61 and allows the steel ball 61 to retract into the retraction portion 68, the intermediate ring 23 and the cylindrical body 50 are in a separated state. ,
When the motor 2 is operated by operating the switch handle 14, the rotation of the motor 2 is transmitted from the intermediate wheel 23 to the drill bit 8 via the spindle 3, but since the motion converting member 5 is turned off Qfi. , the piston 4 does not reciprocate, and only the drill bit 8 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 back with respect to the spindle 3 within the permitted range and strike the striker 33, as shown in FIG. Push backwards to make this move backwards. The striker 33 moves the elastic body 37 and the clutch push 35 rearward, and the protrusion 36 of the clutch push 35 strikes the thrust plate 62 and the spring receiver 63.
The clutch shaft 60 is pushed toward the motion converting member 5 side against the return spring 75 via. As a result, the clutch plate 65 moves toward the motion converting member 5 side while being biased by the pressing spring 76, and the retracting portion 68
In order to position the part with a smaller inner diameter on the outer periphery of the steel ball 61, the ball 61 is pushed inward and
It engages with the engagement recess 27 of. The cylinder 50 holding the steel ball 61 is connected to the intermediate ring 23 via the steel ball 61. For this purpose, the piston 4 is thereafter reciprocated 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. Here, the clutch push 35 and the clutch shaft 60
is directly moved as the drill bit 8 retreats, but the clutch plate 6 that actually connects the clutch 6 is
5, as mentioned above, the movement of the Kukutchi Tsumugi 60 is transmitted only through the pressing spring 76, and for this reason,
Even if the drill bit 8 is suddenly brought into contact with the surface to be drilled, the impact generated at this time is buffered by the pressure spring 76 and is not transmitted to the clutch @ 65, and the impact that occurs at this time is not transmitted to the clutch @ 65. Even if the pressing force against the surface is very large, the force transmitted to the clutch plate 65 is only a force determined by the spring force of the pressing spring 76, and the clutch 6 may be destroyed or damaged due to excessive impact or load. It is something that never happens. Furthermore, even if the force with which the operator presses the drill bit 8 against the surface to be drilled changes slightly during drilling, the force that the clutch plate 65 receives via the pressure spring 76 hardly changes, so that the clutch 6 can be maintained stably. You can get the connection status. When the drilling operation is completed and the drill bit 8 is released from the surface to be drilled, the clutch pongee 60 is returned to its original state by the urging force of the return spring 75, and the clutch plate 65 is also pulled by the clutch pongee 60 and separated from the motion converting member 5. , a retraction portion 6 is provided on the outer periphery of the steel ball 61.
8, the steel ball 61 is retracted to the retraction portion 68 and the clutch 6 is disengaged. Further, the blade 7 tip 35, the striker 33, and the drill bit 8 also return to the state shown in FIG. Therefore, the drill bit 8 is in a state where it only rotates. When drilling holes in iron plates or wood, such as during work, when there is no need to involve striking, all that is required is to operate the release lever 70 shown in FIGS. 4 and 5 provided on the side of the main body housing 1. The separation lever 70 rotatably attached to the bottle 71
A roller 72 which is in contact with the surface of the motion conversion member 5111I on the seventh flange 67 of the clutch plate 65 is freely rotatably supported by a pin 71, and when the separation lever 70 is rotated, the third As shown in the figure, the roller 72 comes into contact with the seventh flange 67, thereby preventing the clutch plate 65 from moving toward the motion converting member 5. For this reason, as shown in the figure, even when the clutch pusher 35 pushes the clutch pongee 61, the clutch 6 is forcibly prevented from engaging. Another embodiment is shown in FIG. The clutch pongee 61 and clutch plate 65, which are directly engaged with each other, are separated in the axial direction, and a pressure spring 76 is disposed between them, and the return spring 75 has one end in contact with the clutch plate 65. However, the operation is the same as that of the above embodiment. [Effects of the Invention] As described above, in the present invention, the clutch push that slides in the ring direction of the drill bit in response to the pressing force of the drill bit against the surface to be drilled and the movement of this clutch push are transmitted to the clutch. Since the clutch is equipped with a spring material that connects the clutch, the clutch is in a disconnected state until the drill bit is pressed against the surface to be drilled, and no power is transmitted to the striking means, resulting in unnecessary vibration. Moreover, the pressing force when pressing the drill bit against the surface to be drilled is transmitted from the clutch push to the clutch via the spring material, so the spring material absorbs the impact force. Moreover, the maximum load applied to the clutch is regulated by the spring force of the spring material, so that the clutch will not be destroyed or damaged due to excessive impact or load. Furthermore, even if the pressing force of the drill bit against the surface to be drilled changes slightly during drilling, the force that the clutch receives through the spring material hardly changes, so the clutch maintains a stable connected state. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the same when the same clutch is connected, Fig. 3 is a longitudinal sectional view when the same as the above clutch is forcibly disengaged, and Fig. 4 is a longitudinal sectional view of the same as the above when the clutch is forcibly disengaged. Broken side view,
Figure m5 is a cross-sectional view of the same as above, Figure 6 is a longitudinal cross-sectional view of another embodiment, Figure 7 and tlIJ8 are cross-sectional views of the conventional example, and Figure 9<8) (b) is a partial perspective view of the same as above. 2 is a motor, 3 is a spindle, 4 is a piston, 5 is a motion conversion member,
6 is a clutch, 8 is a drill bit, 35 is a clutch pusher, 60 is a clutch shaft, 65 is a clutch plate, and 76 is a pressure spring. Agent Patent Attorney Mr. Ishi 1) Figure 7 5

Claims (1)

[Claims] (1) A motor, a spindle that is rotationally driven by the motor and holds the drill bit, and a spindle that is connected to the motor via a motion conversion member to perform reciprocating motion and that is connected to the drill bit via an air spring and a striking body. A hammer drill equipped 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, the hammer drill having a pressing force of a drill bit against a surface to be drilled. A hammer drill characterized by comprising a clutch push that slides in the axial direction of a drill bit in response to a clutch push, and a spring member that transmits the movement of the clutch push to the clutch and connects the clutch.