Abstract: A protective hood assembly for a grinding machine comprising a protective hood having a predetermined size corresponding to the predetermined diameter of the grinding disc; a fastening receptacle attachable to the grinding machine housing and having a shoulder for receiving the protective hood; and a member for securing the protective hood on the shoulder and including a locking portion, the shoulder of the fastening receptacle having an opening for receiving the locking portion upon fastening of the securing member on the shoulder, at least one of shape, arrangement, number, and size of the locking portion and the opening corresponding to the locking portion, being selected in accordance with the predetermined size of the protective hood in such a way as to prevent mounting on the fastening receptacle protective hoods having a size exceeding the predetermined size of the protective hood.

Abstract: A clamping fixture for detachably fixing a disc-like tool to a spindle in cooperation with a tool-fixing member, and comprising a flange member for clamping the tool between the flange member and the tool-fixing member and a supporting element for attaching the flange member to the spindle in a torque-transmitting relationship and having an annular part, the flange member being axially and rotationally displaceable relative to said annular part, the annular part having a first end surface to be axially supported on the spindle and a second end surface and the flange member having an end surface bearing on the second end surface of the annular part with the second end surface of the annular part and the end surface of the flange member having a plurality of complementary sloping end surface portions inclined toward the spindle axis and defining a wedge angle having a size lying in a self-locking range, and the annular part including a plurality of stop surfaces extending substantially parallel to the spindle a

Abstract: A clamping device for portable grinding machines comprising a clamping nut which can be screwed on to the end-side threaded step (13) of the drive spindle (10) to clamp a grinding disk (15) in place. The clamping nut carries a clamping fork (22) which, with its fork leg ends (26, 27), is held so as to be movable about a diametral pivot axis (30) between a clamping position and a loosened position. The ends (26, 27) are provided with eccentric pressing surfaces (28, 29) which decrease with regard to the eccentricity during the pivoting from the clamping position to the release position and act axially on the grinding disk (15) via a pressing disk (36). For releasing, the clamping fork (22) is pivoted about the pivot axis, surface areas of decreasing eccentricity of the pressing surfaces (28, 29) becoming effective. In the process, the thread (14, 20) is relieved and the clamping nut loosened, which can be fully unscrewed manually by taking hold of the clamping fork (22).

Abstract: An actuation device for a switch of a hand machine tool, particularly for a Totmann switch which provides for fatigue-free operation. The actuation device includes a front wall provided with a locking projection engageable in a recess formed in the wall of the switch housing. A restoring spring acts on an actuation member. Two spaced ribs with inclined surfaces are provided on the housing wall. The locking projection slides along the inclined surfaces of the spaced ribs. The locking projection may be broken away from the front wall of the actuation member whereby the end of the front wall would slide along the inclined surfaces of the ribs.

Abstract: A clamping fixture for axially clamping a tool, on a flange of a driven spindle and comprising a clamping nut having an internal thread to be screwed on an end portion with an outer thread of the driven spindle, a clamping member arranged between the tool and the clamping nut for transmitting an axial clamping force to the tool upon tightening of the clamping nut, a manually operable adjustable member freely rotatable relative to the end portion of the driven spindle, and a gearing for gear-coupling the adjusting member to the clamping nut and gear-coupling the clamping nut to the clamping member.

Abstract: An eccentric grinder having a small construction in the axial direction comprises an eccentric (15), which is driven so as to rotate, and a grinding plate (16) which is rotatably supported in the eccentric (15) and which can be set in rotation around its axis of rotation in one or the other rotating direction via rotating rings (26, 27), which are rigidly connected with the grinding plate (16), and via rolling rings (30, 31), which are arranged at the grinder housing (10), in order to change its grinding action. The selection of the rotating direction is determined by means of a manual switching device (38). For this purpose, the rolling rings (30, 31) are held at the grinder housing (10) so as to be rotatable and are in continuous engagement with the rotating rings (25, 26) fastened at the grinding plate (16).

Abstract: An eccentric grinder is provided with a device for changing a grinding motion. The grinder includes a grinding disc eccentrically positioned on a driving shaft and supporting an internal and an external toothed crowns which are brought to a rolling motion on respective external and internal toothed crowns supported on the housing of the grinder. The toothed crowns supported on the housing are axially displaceable by a handle provided externally of the housing. Three various grinding motions for coarse, medium and fine grinding can be obtained by the drive of the grinder.

Abstract: A protective element for a hand-held power tool with a rotary tool, such as a grinding disk, a circular saw, or the like, has a protective member with cut-outs having increased portions, an additional member connectable with the protective member, and connecting elements for connecting the additional member to the protective member and including a plurality of holding screws having heads extending through the increased portions of the cut-outs and engageable behind the protective member, wherein the increased portions have the shape of the plan view of the screw heads and are provided at the same end of the elongated cut-outs, and a locking projection is provided near at least one increased portion in the path of the screw head of the screw sliding in the respective cut-outs.

Abstract: An electric power machine, particularly an angle grinding tool is provided with a centrifugal overspeed protecting device including a fly weight in the form of a severing blade which interrupts a power supply conduit when the rotary speed of the machine is excessive. The protective device includes a cylindrical housing attached face to face to the shaft of the electric motor. The severing blade is in the form of a quadrangular frame defining a center opening. The cylindrical housing is provided with a diametric through bore of a rectangular cross-section matching the frame-like severing blade. A blind bore of a circular cross-section is coaxially superposed on the rectangular through bore and its upper part is formed with inner thread for receiving a setting screw. A helical tensioning spring is inserted in the center opening of the frame-like severing blade and rests on the bottom of the blind bore to urge the centrifugal severing blade against the setting screw.

Abstract: A machine tool, especially a hand-held power tool, comprises a tool spindle and a clamping element turnably mounted on the spindle, in which the turnable clamping element is arrestable during rotation of the spindle for clamping or releasing a tool mounted thereon to thereby make a separate implement for preventing rotation of the clamping element during clamping or releasing the tool on the spindle unnecessary. In a special embodiment of the present invention the clamping or releasing forces during change of the tool are mechanically applied and the turning moment during clamping of the tool is limited to a predetermined value.

Abstract: A protecting hood assembly for use in a motor-driven hand tool such as grinder or circular saw. The assembly includes a hood having a pair of openings, each being formed with a narrowing portion of a squared cross-section and a widened portion forming a slot, a pair of vertically positioned supporting members each having a longitudinal slit and a couple of bolts having each a peripheral portion inserted into said slit and said opening. The widened portion of the opening receiving the bolt is formed with a size in a horizontal direction being larger that a diameter of the peripheral portion of the bolt and a size in a vertical direction being smaller that said diameter to facilitate the installation of the bolt into the hood opening upon assembling and to provide a reliable clamping of said bolt in assembly after insertion thereof.