JPH02106280A - Device for switching over operation mode of electric hammer drill - Google Patents

Abstract

PURPOSE:To easily carry out the switchover of an operation mode by inserting a switchover lever from the outside of a housing and assembling same. CONSTITUTION:A groove is formed on the outer periphery of a movable clutch and the groove is linked to a switchover lever 5 with the switchover lever 5 being eccentric via a lever pin 5e. An engaging spring 7 which is previously housed in spring housing walls 4b provided on a housing 4 is spread and fitted on the switchover lever 5. In this case, the butt portions 7a of the engaging spring 7 and the coming-off stopping projecting portions 5d of the switchover lever 5 are pushed in positions where these are conformed to each other. Then, after one spread in the radial direction, the engaging spring 7 is fixed by the shape restoring force thereof to the ring-shaped groove 5b on the outer periphery of the switchover lever 5. As the switchover lever 5 is switched over, the eccentric lever pin 5e moves the movable clutch to the axial direction of an intermediate shaft, to enable a stationary clutch to carry out the action of disconnecting the transmission of rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an operation mode switching device for an electric hammer drill.

[Conventional technology]

The operation mode switching device of a conventional electric hammer drill is axially movable and rotatably coupled to an intermediate shaft that transmits the rotation of the motor to the piston reciprocating part via the intermediate shaft.
It includes a stationary clutch that engages with the piston reciprocating drive unit, and a dynamic clutch that engages movably on the intermediate shaft. The movable clutch selectively engages with the stationary clutch by a switching lever attached to the outer wall of the housing, and switches the operating mode of the tip tool between rotation, impact, and rotation only.

[Problem to be solved by the invention]

The above-mentioned conventional technology connects the movement of a clutch that transmits and insulates rotation to the piston reciprocating part with a gear to a lever that is operated from the outside, and further provides another shaft and a slide member parallel to the clutch movement direction. A large number of parts are used to prevent the lever from coming off and to control it, resulting in high prices and poor assembly performance. Therefore, there has been a need for a switching lever that has the same function as the switching lever, has a simple structure, is easy to disassemble and assemble, and does not come off during normal operation.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an operation mode switching device for an electric hammer drill that allows easy switching of operation modes.

[Means to solve the problem]

The above purpose is to provide a flexible arm that bends in the axial direction from the end side on the rotation axis of the switching lever, a ring-shaped groove, a rotation prevention protrusion that protrudes in a direction perpendicular to the rotation axis, and a removal prevention protrusion. The housing is provided with a locking recess for the arm that engages with the flexible arm, a spring storage wall that accommodates the locking spring that engages with the ring-shaped groove and rotatably inserts and holds the switching lever, and a rotation prevention protrusion. This is achieved by providing a circumferential detent locking recess that engages with the housing, and assembling the switching lever by inserting it from the outside of the housing.

[Effect]

Since we have provided an article section, the three parts of the switching lever, housing, and locking spring can be assembled by inserting the switching lever from the outside, allowing you to switch modes of rotation and impact with only one rotation, moderation when switching, It becomes easy to prevent the switching lever from coming off once, and the operation mode can be easily switched.

〔Example〕

The present invention will be explained below based on the embodiment shown in the drawing. An embodiment of the present invention is shown in FIGS. 1-7.

The operation mode switching device of the electric hammer drill is movable in the axial direction and rotatably engaged with the intermediate shaft 1 that transmits the rotation of the motor to the piston reciprocating portion via the intermediate shaft 1, and is engaged with the piston reciprocating portion. It includes a stationary clutch 2 that engages with the intermediate shaft 1, and a movable clutch 3 that engages movably on the intermediate shaft 1. - The movable clutch 3 is selectively switched to the stationary clutch 2 by a switching lever 5 mounted on the outer wall of the housing 4.
, and switches the operation mode of the tool (tip tool) 6 to rotation and impact or rotation only (see FIG. 1). In the switching device configured as described above, in this embodiment, on the rotation axis of the switching lever 5, in order from the end side, there is a flexible arm 5a that bends in the axial direction, a ring-shaped groove 5b, and a ring-shaped groove 5b that bends in the direction perpendicular to the rotation axis. Protruding anti-rotation protrusion 5c and anti-slip protrusion 5d
(see Figs. 3 and 4), and engages in the locking recess 4a and ring-shaped groove 5b of the arm that engages with the flexible arm 5a in the housing 4, and inserts the switching lever 5 in a rotatable manner. A spring storage wall 4b for storing the locking spring 7 to be held (see FIG. 2), and a circumferential locking recess 4c that engages with the locking convex portion 5c (see FIGS. 5 and 6) are provided. ), the switching lever 5 is inserted from the outside of the housing 4 for assembly. By doing this, the switching lever 5, the housing 4. The three parts of the locking spring 7 can be assembled by inserting the switching lever 5 from the outside, making it easy to switch modes between rotation and one rotation of impact, moderation during switching, and prevention of the switching lever 5 from slipping out and rotation. Thus, it is possible to obtain an operation mode switching device for an electric hammer drill that allows easy switching of operation modes.

That is, the rotation of the motor is transmitted to the intermediate shaft 1 via the motor output shaft 8 and the first gear 9, and then to the final gear 10.
is constantly rotated, and the tool 6 is rotated via the cylinder 11 and the double roller 12. The piston 13 is biased by a spring 15 coaxial with a clutch pawl 14 formed at the end of a stationary clutch 2 rotatably engaged with the intermediate shaft 1, and is fitted by a spline 16 to the intermediate shaft 1, which is always open. Only when the movable clutch 3 is engaged, the rotation of the motor is transferred to the piston 1 via the reciprocating bearing 17 and the piston pin 18.
3 to reciprocate. An air spring 20 formed between the screw 13 and the striking element 19 causes the striking element 19 to follow the reciprocating movement of the piston 13, and the tool 6 is moved through the intermediate element 21.
(See Figure 1). In addition, 5e in FIG. 1 is a lever pin.

The movable clutch 3 has a groove formed on its outer periphery, and the groove and the switching lever 5 are eccentrically connected to the switching lever 5 via a lever pin 5e. The switching lever 5 pushes out and inserts a locking spring 7 stored in a spring storage wall 4b provided in the housing 4 in advance. At this time,
Push in the abutting portion 7a of the locking spring 7 and the retaining protrusion 5d of the switching lever 5 at the same position (see FIG. 5). A ring-shaped groove 5b formed on the outer periphery of the switching lever 5
After the locking spring 7 is expanded in the radial direction,
It is fixed by the shape recovery force of the locking spring 7.

In addition, when the switching lever 5 is switched, the eccentric lever pin 5e moves the movable clutch 3 in the axial direction of the intermediate shaft 1, so that the operation of transmitting and insulating rotation to the stationary clutch 2 can be performed. Switching lever 5 so that it can be distinguished
The switching lever 5 has a flexible arm 5a that bends in the axial direction on the insertion surface between the housing 4 and the housing 4.
The locking recesses 4a provided on the arms engage with each other to provide moderation, and furthermore, the anti-rotation protrusion 5c of the switching lever 5 engages with the anti-rotation recess 4c provided on the housing 4. , restricts the rotation range of the switching lever 5.

Further, when the switching lever 5 is rotated to a position other than the position where it is assembled by the above-mentioned rotation operation, the retaining protrusion 5d is activated to embrace the locking spring 7, as shown in FIG. In order to prevent the switching lever 5 from coming off in the axial direction, the switching lever 5, the housing 4. The locking spring 7 has a minimum configuration of three parts, and is assembled by inserting the switching lever 5 from the outside of the housing 4, allowing mode switching of only one rotation and one impact rotation, moderation during switching, and removal of the switching lever 5. It can be easily stopped and prevented from rotating.

In this way, according to this embodiment, the switching lever, the housing,
Due to the three-part structure of the locking spring, it is possible to switch the operation mode between rotation and one rotation of impact, and the cost can be reduced by minimizing the number of parts. Furthermore, it is possible to provide a structure in which the switching lever can be reliably attached simply by pushing the switching lever from the outside, and has the effect that the switching lever will not come off during normal switching operations.

〔Effect of the invention〕

As described above, the present invention makes it possible to easily switch the operating mode, thereby providing an operating mode switching device for an electric hammer drill that allows the operating mode to be easily switched.

[Brief explanation of the drawing]

Fig. 1 is a side view of an embodiment of the operating mode switching device for an electric hammer drill of the present invention, Fig. 2 is a plan view of a locking spring of the embodiment, and Fig. 3 is a switching lever of the embodiment. A top view, FIG. 4 is a side view of the switching lever of the embodiment, FIG. 5 is a partial plan view as seen from the direction of the arrow in FIG. 1, and FIG. FIG. 7 is a sectional view taken along line 1--1 in FIG. 5. 1 is an intermediate shaft, 2 is a stationary clutch, 3 is a movable clutch, 4
4a is a housing, and 4a is a recess for arm locking. 4b is a spring storage wall, 4c is a detent locking recess,
5 is a switching lever; 5a is a flexible arm; 5b is a ring-shaped groove; 5c is a rotation preventing protrusion; 5d is a retaining protrusion; 6 is a tool tip; and 7 is a locking spring. Name of patent applicant Nichiq Koki Co., Ltd. Figure 2, Figure 42, 56... Linf 4 sentence A1, 52 Raikya 70

Claims (1)

[Claims] 1. A stationary clutch that transmits the rotation of the motor to the piston reciprocating part via the intermediate shaft, is axially movable and rotatably engaged with the intermediate shaft, and is engaged with the piston reciprocating part; a movable clutch movably engaged on a shaft, the movable clutch selectively engaging the stationary clutch by a switching lever mounted on the outer wall of the housing, and rotating and impacting or rotating the tip tool. In an operation mode switching device for an electric hammer drill, the switching lever includes a flexible arm, a ring-shaped groove, and a ring-shaped groove, which are bent in the axial direction from the end side on the rotation axis of the switching lever.
A locking convex portion and a retaining convex portion protruding in a direction perpendicular to the rotation axis are provided in the housing, and the locking concave portion of the arm that engages with the flexible arm engages with the ring-shaped groove. A spring storage wall for housing a locking spring for rotatably inserting and holding the switching lever, and a circumferential rotation locking projection that engages with the rotation prevention projection, and the switching lever is mounted on the housing. An operating mode switching device for an electric hammer drill, characterized in that it can be assembled by being inserted from the outside.