JPS6339026Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a mounting structure for a change lever of an electric hammer drill having a switching device.

The structure around the change lever of a hammer drill with a conventional changeover mechanism is that the changeover lever is generally separated into a shaft part and a knob part, a detent with a width across flat is provided on both parts, the two parts are fitted together, and a bolt etc. It is combined with .

Furthermore, in order to prevent the change lever from coming off or wobbling, a method was used to incorporate a coil spring and a C spring inside. As a result, bolt fasteners, etc. become loose due to the vibration of the hammer drill body, resulting in a shortened lifespan.Also, due to the large number of parts and complex structure, it is difficult to disassemble and reassemble, and it also becomes larger.
It had drawbacks such as high cost.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to improve the life of the area around the change lever of a hammer drill having this type of switching mechanism, and to reduce the number of parts, thereby reducing the size and cost of production.

The present invention integrates the conventional two-part change lever into a single part, and eliminates the screw part in order to prevent the screw from loosening due to vibration.

Furthermore, by devising the bending shape of the spring steel wire, we devised a spring member that has spring properties in two directions, and locks the change lever and the spring member to securely hold the change lever in a narrow space. It has been carefully devised.

In FIG. 1, by turning on the switch 24 built in the switch handle 22, the first gear 2 in the motor section 1 rotates, and the second gear 3, third gear 4, fourth gear 5, and fifth gear rotate. Rotation is transmitted to gear 6. The rotation of the fifth gear 6 is controlled by the cylinder 8 connected to the key 7 and the tip tool 9 engaged with this cylinder 8.
It is transmitted to On the other hand, the rotation of the second gear 3 is pressurized by a spring 19, and the steel ball 10 locked to the slide shaft 18 connects the second gear 3 and a crankshaft 11 having an eccentric shaft to transmit the rotation. The rotation of the crankshaft 11 causes a piston 14 to reciprocate by a connecting rod 12, and a striker 15 slidably fitted in a cylinder 18.
This causes a striking motion to be applied to the tip tool 9.

When the change lever 16, which can rotate at a certain angle, is manually rotated, the eccentric shaft 17 of the change lever 16 pushes up the slide shaft 18, draws the steel ball 10 toward the shaft center, and connects the second gear 3 and crankshaft 11. Unbind. As a result of the above, the rotation of the crankshaft 11 is stopped, and only the rotation is transmitted to the tip tool 9.

The change lever 16 is assembled as shown in FIG. The change lever 16 to which the lubricant sealing O-ring 25 is attached is inserted from the outside of the gear cover 28 in the change lever insertion direction 30. To prevent the change lever 16 from coming off, a spring member 26 is inserted from a spring member insertion direction 3 perpendicular to the direction in which the change lever 16 is inserted. This spring member 26 has a radial spring portion 32 and engages with the small diameter portion 27 of the change lever 16 to prevent the spring member 26 from coming off due to vibration of the main body. Furthermore, it has an axial spring portion 33, and a side surface 3 of the cut-up portion between the inner wall of the gear cover and the small diameter and large diameter of the change lever 16.
4, and generates a force in the axial direction of the change lever 16. It prevents the change lever 16 from floating due to vibrations caused by the impact movement of the main body, and also serves as a reliable stopper.
The side walls 29 on both sides of the gear cover 28 have spring members 26
prevent from falling. With the spring member 26, change lever 16, and gear cover 28 configured as described above, it is possible to provide an inexpensive, lightweight, and compact change lever mounting structure with a small number of parts.

According to the present invention, the change lever, the spring member,
The change lever can be reliably held by configuring the gear cover, which corresponds to the outer frame, to have the minimum number of parts necessary. This increases the lifespan of the change lever area by eliminating screws loosening due to vibration, and also reduces the number of parts, simplifies disassembly and assembly, reduces costs, and reduces size and weight due to the compact structure. can play.

[Brief explanation of the drawing]

Fig. 1 is a partial vertical sectional side view of a hammer drill showing an embodiment of the change lever mounting structure according to the present invention, Fig. 2 is a sectional view taken along the line - - of Fig. 1, and Fig. 3 shows the mounting method. FIG. In the figure, 16 is a change lever, 26 is a spring member, 27 is a small diameter portion, 28 is a gear cover, 32 is a radial spring portion, and 33 is an axial spring portion.

Claims (1)

[Scope of utility model registration request] In a hammer drill that has a switching device that performs drilling, chiseling, etc. by applying 10 impact rotations, only rotation, or only impact to the tip tool, the change lever of the switching device has an axial spring portion and a spring portion perpendicular to the axis. a change lever having a small diameter portion with which the spring member engages, and a gear cover in which the spring member and the change lever are housed, and the change lever is rotatable. Mounting structure of the change lever that is installed.