Patent ID: 12220801

DETAILED DESCRIPTION

A preferred exemplary embodiment of a hammer drill and/or chipping hammer100according to the invention is illustrated inFIG.1. The hammer drill and/or chipping hammer100is equipped with an electric drive motor70, an impact mechanism10and a tool fitting50for fitting a tool110. The impact mechanism10, which is arranged in a housing90, has an anvil30that is displaceable in the axial direction AR in an anvil guide20and acts on the tool110.

The impact mechanism10has an idle-strike damper element11and a rebound-strike damper element13. The idle-strike damper element11and the rebound-strike damper element13are formed in one piece with one another and as such form a combined damper element15. The combined damper element15has a central cutout40, which extends along the entire length L (cf.FIG.2B) of the combined damper element15. The anvil30is received at least partially within the central cutout40and guided through the latter.

As is apparent fromFIG.1, the anvil guide20has two rolling bearings21,23, which are arranged entirely outside the combined damper element15. The anvil30is thus not mounted within the combined damper element15or by the combined damper element15itself.

The anvil30is formed in a cylindrical manner and has a radial bead31approximately in the middle. The radial bead31is arranged so as to strike the idle-strike damper element11on one side (left-hand side inFIG.1) and to strike the rebound-strike damper element13on the other side (right-hand side inFIG.1).

The combined damper element15has a cylindrical inner surface16, which extends in the axial direction AR between an idle-strike stop surface12of the idle-strike damper element11and a rebound-strike stop surface14of the rebound-strike damper element13. In other words, the cylindrical inner surface16is bounded on one side by the incipient idle-strike stop surface12and on the other side by the incipient rebound-strike stop surface14, in each case as seen in the axial direction AR. Provided between the cylindrical inner surface16and the bead31, to be more precise between the cylindrical inner surface16and the thickest point32, in the radial direction RR, of the bead31, is a radial gap19(particularly readily apparent inFIG.2B, too). The radial gap19extends along the entire inner surface16, i.e. at no point between the idle-strike stop surface12and the rebound-strike stop surface14is the thickest point32of the bead31in contact with the cylindrical inner surface16of the combined damper element15. Therefore, undesired abrasion of the combined damper element15is effectively avoided.

FIGS.2A and2Bshow a first preferred exemplary embodiment of a combined damper element15, as can be used for example in the hammer drill and/or chipping hammer100inFIG.1.FIG.2Ashows the combined damper element15as seen from the tool fitting50. It is readily apparent that the combined damper element15has a planar frontal stop surface51, via which the combined damper element15is supported on a shoulder52(cf. alsoFIG.1) of the tool fitting50.

The combined damper element15inFIG.2Aconsists for example of an elastomer material and is formed by two half-shells15′,15″, which make mounting easier. A parting plane18between the half-shells15′,15″ extends parallel to the axial direction AR.

FIG.2Bshows a section through the combined damper element15along the parting plane18. The central cutout40, which is bounded by the annular, planar frontal stop surface51, is readily apparent inFIG.2A. The central cutout40extends along the entire length L of the combined damper element15. The anvil30(schematically indicated here) is received at least partially within the central cutout40. Provided between the cylindrical inner surface16and the bead31, to be more precise between the cylindrical inner surface16and the thickest point32, in the radial direction RR, of the bead31, is the above-described radial gap19.

In the combined damper element15inFIG.2B, the idle-strike damper element11exhibits greater impact stiffness than the rebound-strike damper element13. This is achieved by structural design solely in that—with respect to the axial direction AR—“extra” elastomer material is used in the idle-strike damper element11compared with the rebound-strike damper element13. If the idle-strike damper element11has more of a cylindrical ring-shaped cross section Q11, a cross section Q12of the rebound-strike damper element13widens in the manner of a diffuser (to the right inFIG.2B).

A second preferred exemplary embodiment of a combined damper element15is illustrated inFIGS.3A and3B. In addition to the exemplary embodiment illustrated inFIGS.2A and2B, in the case of the combined damper element15inFIGS.3A and3B, a longitudinal slot17is provided, which extends axially along the combined damper element15(from the left-hand side inFIG.3A) on the tool-fitting side. The longitudinal slot17ensures air exchange so as to avoid the anvil being drawn by negative pressure against the idle-strike stop surface12.FIG.3Ashows the combined damper element15in a relaxed state, i.e. the anvil is, as can be seen for example inFIG.2B, in a central position. InFIG.3B, the combined damper element15, to be more precise the idle-strike damper element11, is shown in the compressed state. Of the longitudinal slot17there remains a residual opening17′, via which air exchange is possible even in the case of a compressed idle-strike damper element11.

LIST OF REFERENCE SIGNS

10Impact mechanism11Idle-strike damper element12Idle-strike stop surface13Rebound-strike damper element14Rebound-strike stop surface15Combined damper element15′,15″ Half-shells16Cylindrical inner surface17Longitudinal slot17′ Residual opening18Parting plane19Radial gap20Anvil guide21,23Rolling bearing30Anvil31Radial bead32Thickest point40Central cutout50Tool fitting51Planar frontal stop surface52Shoulder70Drive motor90Housing100Hammer drill and/or chipping hammer110ToolAR Axial directionRR Radial directionQ11, Q12Cross sections