JPH0230835B2 - KEITAIYODENDOKOGUNOOFUKUDOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reciprocating device for a portable power tool having a reciprocating mechanism, such as an electric hammer.

2. Description of the Related Art As a reciprocating device for a portable power tool having a reciprocating drive member, one using a piston-crank mechanism is known. Although this mechanism can transmit a large amount of power, the axis of rotation of the crank is perpendicular to the direction of reciprocating motion. This places the prime mover shaft at right angles to the direction of reciprocation. Alternatively, it is necessary to arrange the motor shaft in the reciprocating direction and additionally provide a mechanism for changing the direction of the rotary shaft, which may impair the compact and lightweight structure necessary for a portable tool. In view of this point, a reciprocating mechanism is also known in which a motor shaft is arranged in the reciprocating direction and a cam is used to obtain reciprocating motion. However, since this known mechanism uses a cam, the cam surface and the driven body move in point or line contact, and therefore have the disadvantage that large amounts of power cannot be transmitted. In order to compensate for this drawback, it becomes necessary to increase the size of the cam device, thus defeating the original purpose of obtaining a compact and lightweight structure.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a portable tool having a reciprocating device that is small and lightweight.

The present invention uses a link mechanism instead of a cam to drive the swinging arm, and the connection points form a rotational couple, so the point or line contact part required for a cam can be eliminated, and a large amount of power is generated. It was designed so that it could be transmitted.

FIG. 1 shows a specific example of an electric hammer drill having a reciprocating device according to the present invention. In the figure, 1
is the prime mover, 2 is the prime mover shaft, 3 is the inclined crank, 4
is a swinging arm, 5 is a rotating arm, 6 is a pivot pin, 7 is a piston pin, 8 is a piston, 9 is a cylinder, 1
0 is a striking element, 11 is an intermediate element, 12 is a tool holder,
13 is a gear, and 14 is a tool. In such a configuration, the rotation of the prime mover 1, which is installed so as to have a rotation axis parallel to the reciprocating axis of the piston 7, is caused by rotation of the prime mover 1, which is installed on the outer periphery of the crown portion of the inclined crank 3, which meshes with a gear provided at the tip of the prime mover shaft 2. The inclined crank 3 is rotated through the rotated gear. The tilting shaft of the tilting crank 3 is formed as a hole provided in the crank crown, and the axis of the hole rotates on a cone having its apex at a point on the rotation axis of the tilting crank. A bearing 15 is installed in the hole, and the rotating arm 5 is coupled in a pairwise relationship. The rotary arm 5 is rotatably installed around a swinging arm 4, which is installed at the apex of the cone so as to be swingable about a pivot pin 6 fixed on the casing 16 in a direction perpendicular to the crank rotation axis. Moreover, since the axis of the rotary arm 5 passes through the apex of the cone, the rotary arm 5 rotates on the cone by the rotation of the inclined crank 3. Due to the rotational movement of the rotating arm 5, the swinging arm 4 swings around the pivot pin 6 by the apex angle of the cone. The rotational motion component of the rotary arm 5 in the direction perpendicular to the oscillating plane is absorbed by the rotary arm rotating about the oscillating arm 4 as an axis. The swinging arm 4 is a piston pin 7
The piston 8 is connected to a piston 8 which is a driving member through the oscillating arm 4.
It is driven back and forth using the inner periphery of the cylinder 9 as a guide. The striking element 10 is reciprocated by the piston 8 via an air action and strikes the intermediate element 11. This impact energy is transmitted through the meson 11 to the tool 14 held in the tool holder 12. On the other hand, a gear provided at the shaft end of the inclined crank 3 meshes with the gear 13 to rotate it. The gear 13 is non-rotatably connected to the tool holder 12, and is connected to the tool 1 through the tool holder.
4 to rotate.

According to the present invention, it is possible to obtain reciprocating motion parallel to the prime mover shaft without using a rotational direction change mechanism, so a portable power tool with a reciprocating motion mechanism can be made compact and lightweight. . Also, compared to using a cam to obtain reciprocating motion,
Since there are no points or line contacts, a reciprocating mechanism capable of transmitting relatively large power can be obtained. Further, since the swinging arm swings in one plane by the pivot pin, no force is applied to the piston pin in a direction perpendicular to the swinging plane, which inevitably occurs in other similar mechanisms.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional side view showing an embodiment of the reciprocating device according to the present invention, FIG. FIG. 2 is a front view of FIG. 2; In the figure, 3 is a tilting crank, 4 is a swinging arm, 5 is a rotating arm, 8 is a piston,
9 is a cylinder.

Claims (1)

[Claims] 1. A reciprocating device for a portable power tool having a drive member that reciprocates in an axial direction guided by a guide means, wherein the drive member oscillates around an axis perpendicular to the direction of the reciprocating motion. In a device that is reciprocated by the swinging of a swinging arm, the swinging arm has this as a rotational axis, and has a rotating arm extending perpendicular to the rotational axis, and rotating the rotating arm. A reciprocating device characterized in that it is driven by a tilting crank.