Hand-held power tool with ratchet percussion mechanism

Abstract

An electric hand-held power tool (2) has a main housing (4) of a shell-type construction a tool spindle (14) projecting from the main housing (4) at a working tool-side end (18) of the housing and which can be rotated around a operational axis (A) by a motor (12) and a gear unit (16) which are accommodated in the main housing (4), with an axial percussion movements being applied to the tool spindle (14) by a ratchet percussion mechanism (38) having a toothed rim (43), which is fixed with respect to the housing and which is connected to a supporting body (44) that is supported in the main housing (4), the toothed rim (43) cooperating with a toothed rim (41) which is movable so as to be coupled with the tool spindle (14) for joint rotation therewith, and the supporting body (44) being supported by a supporting element (58) in a direction remote from the working tool-side end (18) of the housing, with the supporting element (58) being formed in a circumferentially extending manner at an inner surface (56) of an outer shell (34) of the main housing (4), and the supporting body (44) directly contacting the supporting element (58).

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention relates to an electric hand-held power tool including a main housing, formed particularly of a plastic material and having a shell-type construction, and a tool spindle which can be connected to a tool holder for joint rotation therewith and which projects from the main housing at its working tool-side end. The tool spindle can be rotated around a operational axis by a motor and a gear unit which are accommodated in the main housing. In addition, axial percussion movements can be applied to the tool spindle along the operational axis by a ratchet percussion mechanism. For this purpose, the ratchet percussion mechanism has a toothed rim which is fixed with respect to the housing and which is connected to a supporting body that is supported in the main housing. The toothed rim cooperates with a toothed rim which is movable so as to be coupled with the tool spindle for joint rotation therewith, and the su...

AI Technical Summary

Benefits of technology

The present invention aims to improve the efficiency and stability of a hand-held power tool by eliminating disadvantages and increasing operational efficiency. This is achieved by incorporating supporting means that extend circumferentially at the inner surface of the outer shell of the main housing and directly contacts the supporting means. The supporting body forms a radial contact surface that contacts the outer shell in radial direction, providing stability to the main housing and imparting greater stability to external loads on the main housing. The supporting body is advantageously made of metal, which increases the mass and stability of the area responsible for supporting action. The supporting body is held at a gear unit housing, further stabilizing the gear unit housing and facilitating assembly. Bearing recesses for guiding slip clutch means are incorporated in the supporting body, reducing wear. The invention reduces the quantity of individual components and takes on an additional function of guiding slip clutch means.

Problems solved by technology

Due to relative movements of the two housing parts caused by deformations, impact energy losses occur particularly between the main housing and the portion of the inner housing that is supported at a relatively large distance from the latter.

This can impair operational efficiency particularly in comparison with tools of cup-type construction which also have main housing portions that extend transverse to the operational axis and support the supporting body axially form behind.

Also, a tool of the kind mentioned above which has a shell-type construction, usually a plastic housing, in order to reduce weight, is relatively susceptible to forces acting on the housing from the outside transverse to the operational axis.

For example, attaching a side handle with a clamping band that is securely clamped around the housing, can lead to a deformation of the housing.

These deformations can lead, in turn, to malfunction or complete blocking of components of the tool such as the gear unit, a torque clutch, or an on / off circuit of the percussion device, for example.

Images