JPH0657567U - Hammer drill switching mechanism - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the eccentric pin from interfering with the clutch member when installing or removing it, to facilitate the work. [Structure] A clutch member 17 is fixed to a crankshaft 19 which is rotatably supported by a housing. Crankshaft 19
A second gear 15 is also rotatably supported on the second gear 15, and an engagement pin 16 is fixed to the second gear 15. The clutch member 17 has an engagement hole 17b into which the engagement pin 16 can be engaged.
Are formed. A flange portion 17a is formed on the outer periphery of the clutch member 17, and a switching lever 25 having an eccentric pin 26 that can be engaged with and disengaged from the flange portion 17a is rotatably provided on the housing. Then, at the installation position of this switching lever 25, the eccentric pin 26 has
It is set so that the eccentric pin 26 can be located outside the outer periphery of the clutch member when it is located away from 7a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hammer drill switching mechanism.

[0002]

[Prior art]

 Generally, a hammer drill is widely known as a device for making a hole in a work material such as concrete. In such a hammer drill, it is necessary to selectively use a case where a rotating force and a striking force are simultaneously applied to a bit to act as a hammer drill, and a case where only a rotating force is applied to act as a normal drill. There are things you can do.

In this case, the rotational force of the motor shaft can be transmitted to both the drive system of the percussion drive system and the drive system of the rotary drive system via the gear transmission mechanism, and the transmission to the percussion drive system can be interrupted by the switching mechanism. I am configuring.

FIG. 4 shows a conventional switching mechanism. Reference numeral 101 in the drawing denotes a motor shaft, and a tooth portion 101a is formed on the motor shaft 101, and a first gear 102 and a second gear 103 are meshed with the tooth portion 101a. Here, the first gear 102 is a rotary drive system, and the second gear 103 is a percussion drive system. Two engaging pins 104, 104 are provided on the second gear 103 so as to project therefrom. Further, a clutch member 105 is disposed coaxially with the second gear 103, and engagement holes 105a and 105a which can engage with the engagement pins 104 and 104 are formed. Further, a switching lever 107 is rotatably provided on the housing 106, and an eccentric pin 108 is eccentrically attached to the switching lever 107. Here, the eccentric pin 108 can be engaged with and disengaged from the flange portion 105b of the clutch member 105, and the tip end of the eccentric pin 108 is located inside the clutch member 105 in both the contact state and the separated state.

[0005]

[Problems to be solved by the device]

 However, in the above-mentioned configuration, the tip of the eccentric pin is located inside the clutch member during assembly, so the switching lever must be installed in the housing after inserting the clutch member into the crankshaft. When exchanging the clutch member etc., the switching lever had to be always removed from the housing. Further, since a spring is interposed between the clutch member and the crankshaft, the clutch member must be pressed when the switching lever is assembled into the housing, which complicates the work. In addition, the switching lever contains a positioning spring and steel balls for switching, and the clutch member must be pressed by hand and assembled into the housing while being careful not to drop the steel balls. There is a problem that is complicated.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a hammer drill switching mechanism which can be easily assembled and repaired.

[0007]

[Means for Solving the Problems]

 The present invention is directed to a rotary drive device, a rotary body rotated by the rotary drive device, a first engagement portion provided on the rotary body, and a second engagement engageable with the first engagement portion. And a clutch member movable in the axial direction, a hammer drill switching mechanism is provided with an operating portion that abuts a flange portion of the clutch member to move the clutch member in the axial direction. , The operating portion includes a lever portion and an eccentric pin eccentrically provided on the lever portion. The eccentric pin is brought into contact with the flange portion to move the clutch member in the axial direction, The engagement between the engagement portion and the second engagement portion is released, and the first engagement portion and the second engagement portion are engaged by separating the eccentric pin from the flange portion, and The eccentric pin is Characterized in that from the outer peripheral member is located outside.

[0008]

[Action]

 When the bit and the hammering force are simultaneously applied to act as a hammer drill, the eccentric pin is separated from the flange portion of the clutch member and the first engaging portion and the second engaging portion are engaged with each other. As a result, the rotation of the rotating body rotated by the rotation drive device is transmitted to the clutch member, and the crankshaft is rotated.

Further, in the case where only the rotational force is applied to the bit to act as a normal drill, the operating portion is operated to bring the eccentric pin into contact with the flange portion, and the clutch member is moved to move the first engaging portion. And the second engagement portion are disengaged. As a result, even if the rotating body rotates, the clutch member does not rotate and the transmission of rotational force is interrupted.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partial front sectional view of a hammer drill according to the present invention. Reference numeral 1 in the drawing is a housing, and a motor 2 is attached to the housing 1. A tooth portion 2b is formed on the motor shaft 2a of the motor 2. An intermediate shaft 4 is rotatably supported by the housing 1 via bearings 3 and 27, and a first gear 5 is fixed to the intermediate shaft 4. The first gear 5 is meshed with the tooth portion 2b. A first bevel gear 6 is fixed to the intermediate shaft 4, and the first bevel gear 6 meshes with a second bevel gear 7 rotatably supported by the housing 1. A rotary cylinder 9 is attached to the second bevel gear 7 via a key 8. A drill holder (not shown) for transmitting the rotating force to the bit is provided in the rotary cylinder 9. This constitutes the rotary drive system 11.

Next, the structure of the striking drive system 12 will be described in detail. A crankshaft 19 is provided on the housing 1 via bearings 13 and 18, and a second gear 15 is rotatably provided on the crankshaft 19. The second gear 15 meshes with the tooth portion 2b of the motor shaft 2a. Two engaging pins 16 and 16 are fixed to the second gear 15, and the clutch member 17 is attached to the crank shaft 19 on the protruding side (upper side in the figure) of the engaging pins 16 and 16. It is provided so as to be movable in directions and rotatable integrally. A spring 20 is interposed between the clutch member 17 and the bearing 18 to constantly urge the clutch member 17 downward in the drawing. Further, the clutch member 17 is formed with engagement holes 17b, 17b with which the engagement pins 16, 16 can be engaged. An eccentric crank pin 21 is provided on the upper end surface of the crank shaft 19 in the drawing, and one end of a conrot 22 is pivotally attached to the crank pin 21. A piston 23 that reciprocates in the rotary cylinder 9 is fixed to the other end of the controller 22, and a hammer 24 that strikes the spindle 10 is provided on the piston 23.

FIG. 2 is a view taken along the line II-II in FIG. Here, the switching lever 25 is rotatably supported by the housing 1 located in the middle of the first gear 5 and the second gear 15. An eccentric pin 26 is provided on the inner side of the switching lever 25 (upper side in the figure). Here, the eccentric pin 26 is positioned so as to be disengageable from the flange portion 17a formed on the clutch member 17. In particular, when the eccentric pin 26 is located at a position separated from the flange portion 17a of the clutch member 17, the eccentric pin 26 is positioned outside the clutch member 17 (broken line in the figure).

A hole (not shown) is formed in the switching lever 25, a spring (not shown) and a steel ball (not shown) are housed inside the hole, and the steel ball is formed by the spring. Energized outward. Further, the housing 1 is formed with a groove into which the steel ball can be engaged, and the switching lever 25 is positioned by engaging the steel ball into the groove.

In the hammer drill configured as described above, when the bit is given a rotational force and a striking force at the same time to act as a hammer drill, the switching lever 25 is rotated as shown in FIG. 3A. The eccentric pin 26 is separated from the flange portion 17a of the clutch member 17. Then, the urging force of the spring 20 moves the clutch member 17 downward in FIG. 3 (a) to engage the engagement pin 17 with the engagement hole 17b. As a result, the rotational force of the second gear 15 is transmitted to the clutch member 17, the crankshaft 19 rotates, and the piston 23 (FIG. 1) reciprocates. As a result, the hammer 24 hits the spindle 10.

Further, when only the rotational force is applied to act as a normal drill, as shown in FIG. 3 (b), the switching lever 25 is rotated and the eccentric pin 26 is applied to the flange portion 17 a of the clutch member 17. The clutch members 17 are brought into contact with each other and moved upward in the drawing. As a result, the engagement state between the engagement pin 16 and the engagement hole 17b is released. Therefore, even if the second gear 15 rotates, this rotational force is not transmitted to the clutch member 17, and the hammer 24 does not hit the spindle 10.

Next, an outline of a method of assembling the switching mechanism section will be described. In FIG. 1, the bearing 18 is press-fitted into the housing 1, and the crankshaft 19 is inserted into the bearing 18 to prevent the bearing from coming off. Next, in FIG. 2, the switching lever 25 accommodating the spring and the steel ball is inserted into the housing 1 to prevent it from coming off. At this time, the eccentric pin 26 is already fixed to the switching lever 25. Then, the switching lever 25 is operated to position the clutch member 17 and the spring 20 in the crankshaft 19 in the state of FIG. 3 (a). At this time, since the eccentric pin 26 does not interfere, the work can be easily performed. Further, the clutch member 17 is pressed to the state shown in FIG. 3B, and the eccentric pin 26 is also brought to the state shown in FIG. 3B. As a result, the clutch member 17 is held in this state. Then, the second gear 15 is rotatably held on the crankshaft 19. In this way, the striking drive system 12 is assembled.

[0017]

[Effect of device]

 Since the present invention is configured as described above, it has an effect that the work can be easily performed by releasing the eccentric pin when the clutch member is attached or detached.

[Brief description of drawings]

FIG. 1 is a partial front sectional view of a hammer drill according to the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a view for explaining the operation of the hammer drill in the present invention.

FIG. 4 is a sectional view of a main part of a conventional hammer drill.

[Explanation of symbols]

 2 ... Motor (rotary drive device) 15 ... Second gear (rotating body) 16 ... Engaging pin (first engaging portion) 17 ... Clutch member 17a ... Flange portion 17b ... Engaging hole (second engaging portion) 25 ... Switching lever 26 ... Eccentric pin

Claims (1)

[Scope of utility model registration request] 1. A rotary drive device, a rotary body rotated by the rotary drive device, a first engagement portion provided on the rotary body, and a second engagement member which can be engaged with and disengaged from the first engagement portion. In a hammer drill switching mechanism provided with a coupling portion and an axially movable clutch member, an operating portion for contacting a flange portion of the clutch member to move the clutch member in the axial direction is provided. , The operating portion includes a lever portion and an eccentric pin eccentrically provided on the lever portion, the eccentric pin is brought into contact with the flange portion, and the clutch member is moved in the axial direction. The engagement between the engagement portion and the second engagement portion is released, and the first engagement portion and the second engagement portion are engaged by separating the eccentric pin from the flange portion, and The eccentric pin is the clutch part A hammer drill switching mechanism characterized in that it is positioned outside the outer circumference of the material.