Percussion Mechanism and at Least Percussively-Operated Hand Machine Tool With a Percussion Mechanism

Abstract

The invention relates to a percussion mechanism for an at least percussively-operated hand machine tool, in particular a hammer drill or chisel, comprising a drive motor and a tool holder (10) for housing a tool, with a percussive pin (12) acting on the tool which is axially displaceable within a percussive pin guide (11). The percussive pin guide (11) has a body (13) enclosing the percussive pin (12). According to the invention, the body (13) is made from two materials of differing hardness. The invention further relates to an at least percussively-operated hand machine tool, in particular a hammer drill or chisel with a percussion mechanism.

Description

PRIOR ART[0001]The invention is based on a percussion mechanism and an at least percussively drivable hand power tool having a percussion mechanism, as defined by the preambles to the independent claims.[0002]In the prior art, a percussion mechanism of percussively drivable hand power tools, such as drill hammers and / or percussion hammers, in order to transmit a percussion pulse, often includes a so-called header or percussion bolt, which is axially displaceably supported in a percussion bolt guide and is acted upon on the drive end with blows by a beater of the percussion mechanism in the drilling or percussion direction. The percussion energy of the blows is transmitted by the percussion bolt to a face end on the drive end of the tool that is received in the tool holder. A lubricant-filled interior of the percussively drivable hand power tool is thus sealed off from the outside. The percussion bolt, typically made from steel, is guided in hard fashion in the tool holder, or in a s...

AI Technical Summary

Benefits of technology

[0005]In the version according to the invention, the body is embodied in two parts, with a drive part of the body comprising the elastomer material and a tool part of the body comprising steel. Preferably, the two parts have a continuous axial recess for the percussion bolt, and the percussion bolt is limitedly axially displaceable in the recess between an idling position and a percussion position. Expediently, the thus-shaped parts of the body have a guide function for the percussion bolt. In particular, the tool part of the body may have an inner idling impact stop shoulder, against which the percussion bolt rests in the idling mode. The drive part of the body preferably has a B-impact stop shoulder, which damps the recoil of the percussion bolt after the transfer of the percussion pulse to the tool. Because of the embodiment according to the invention of the drive part of the body of elastomer, the deceleration of the percussion bolt in its reverse motion in the percussion mode is damped.

[0006]In an embodiment of the invention, a sealing element can be located on an on an inner and / or outer jacket face of the drive part of the body. As a result, even better sealing action can favorably be attained, especially against the entry of dirt from outside. The sealing element preferably annularly surrounds the percussion bolt.

[0007]The drive part of the body may be shaped such that besides guiding the percussion bolt, it performs one or more other functions, such as a sealing function and / or an idling function in idling impact or B-impact, in order to damp the recoil that then occurs and to brace the drill in the device. For performing another additional function, a beater catch ring may be integrated with the drive part of the body, in order to catch the beater in the idling mode. By means of the thus-shaped drive part of the body, which performs multiple functions simultaneously, it is favorably possible to dispense with furnishing separate components.

[0009]It can be provided that the tool part of the body is longer than the drive part. Alternatively, a length ratio between the tool part and the drive part of the body can be transposed, with the drive part of the body being longer than the tool part. As a result, depending on the design of the device, various geometric variations can be attained.

Problems solved by technology

In particular, in machining contact faces of the percussion bolt and of the tool holder or of the hammer barrel, certain minimum tolerances cannot be allowed to be exceeded, so as to keep the components in the percussion line and thus assure only slight transverse forces.

The proposed steel version is thus quite cost-intensive.

A disadvantage, however, is that the reflection performance of the elastomer material differs from that of steel, which has unfavorable effects on the idling function which was unproblematic in the earlier steel version.

Furthermore, when used in higher-quality devices, the expected service life is shorter, which in turn adversely affects the cost factor.

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