Guard for an electric machine tool, electric machine tool, and system comprising a guard and electric machine tool

#The present invention is directed to a guard for a power tool, a power tool, and a system composed of guard and power tool.

#It is known to provide guards for power tools with rotatably driven insertion tools—angle grinders in particular—to protect an operator from injury that could occur if the insertion tool shatters and fragments are slung outward.

#The present invention is directed to a guard for a power tool with a rotatably driven insertion tool, with which at least portions of the insertion tool can be covered.

#Further advantages result from the description of the drawing, below. Two exemplary embodiments of the present invention are shown in the drawing. The drawing, the description and the claims contain numerous features in combination. One skilled in the art will also advantageously consider the features individually and combine them to form further reasonable combinations.

#FIG. 1 Shows a preferred angle grinder,

#FIG. 2 Shows a schematic depiction of a side view according to a first exemplary embodiment,

#A power tool designed as a preferred angle grinder is shown in FIG. 1. An electric motor (not shown) is located in a housing 10, the electric motor rotatably driving an insertion tool 14, which is a grinding disc in this case. With an angle grinder, an output shaft of the electric motor is usually positioned perpendicularly to a drive shaft of the insertion tool. The angle grinder can be held and guided using a handle 12 that projects outwardly at an angle. A guard 16 covers insertion tool 14 to the extent that protection against contact by an operator is ensured. Guard 16 is designed as a semicircle with a flange on the periphery, the flange extending downward at the periphery and covering half of the surface and the edge of grinding disc 14. Guard 16 includes, e.g., a flange 30 projecting upwardly from the center of its imaginary circular area and extending substantially parallel to an axis of rotation 18, with a clamp 26 attached thereto, and is fixed to a collar 24 by way of said clamp 26 (FIGS. 2-5).

#To ensure—if insertion tool 14 shatters—that guard 16 is not rotated so far that fragments can strike the operator, a rotation-prevention means 20 is provided according to the present invention that at least limits guard 16 from rotating around an axis of rotation of insertion tool 14 and/or collar 24.

#FIGS. 2 through 5 show a first preferred exemplary embodiment of a rotation-prevention means 20. In the figures, components that are basically identical are all labeled with the same reference numerals. A blocking means in the form of a stop cam 32 is provided, on the guard side, on a collar 24 of a drive shaft 22, the blocking means being formed in a clamp 26 for attaching a guard 16 to collar 24, and which is pressed through toward the inside of clamp 26 (FIG. 4). An insertion groove 36 with a limiting groove 34 extending substantially perpendicular thereto is provided in collar 24, the limiting groove forming a stop means that corresponds with stop cam 32. If guard 16 is rotated when insertion tool 14 shatters, limiting groove 34 limits a possible rotation around an axis of rotation 18 to an angular range α (FIG. 3). The rotation is blocked independently of a torque used to tighten an attachment screw 28 used to fix clamp 26 around collar 24, the rotation being blocked by one end or the other end of limiting groove 34.