Abstract: A power tool includes a motor, a rotary disk, a belt drive connecting the motor to the rotary disk, and a reduction gear stage between the motor and the belt drive. A power tool with a ratio of an outer diameter of the drive pulley and an outer diameter of the output pulley being 0.75 to 1.33 is also provided as is a method of operating a power tool.

Abstract: A protection device for a power tool is provided. The power tool can be, in particular, a hand-held battery-operated power tool, such as a cut-off grinder. The power tool preferably has main components in a main region, such as a motor, transmission and rechargeable batteries, which are protected effectively from mechanical damage, e.g. when dropped, by the protection device. Moreover, the protection device prevents the transmission of vibrations in the power tool to the user. In a second aspect, the invention relates to a system which comprises a protection device and a power tool.

Abstract: A drive shaft for a machine tool is connectable to a drilling tool. The drive shaft contains a cavity extending substantially over the entire length of the drive shaft and along the axis of rotation where the cavity contains an inflow opening through which water can be fed along the drive shaft into the drilling tool. An insert device is provided in the cavity, through which, to cool the drive shaft, the water is guided first in a first direction and then in a second direction where the insert device contains a first curved guide element and a second curved guide element for separating the water which is guided in the first direction from the water which is guided in the second direction. The cross-sectional area of the first curved guide element is designed point-symmetrically about a center longitudinal axis to the cross-sectional area of the second curved guide element.

Abstract: A drive shaft for a machine tool, for example a core drilling machine, able to be connected to a drilling tool, in particular a core bit, is disclosed. The drive shaft contains a cavity which substantially extends over the whole length of the drive shaft and along the rotational axis. The cavity contains at least one inflow opening where, through the at least one inflow opening, water can be fed along the drive shaft into the drilling tool. In the drive shaft, an insertion device is provided in the cavity, through which water is guided for cooling the drive shaft, firstly, in a first direction and then in a second direction, where the water comes into direct contact with the inner side of the cavity at least in the first direction.

Abstract: A device for holding and securing a tool, in particular, a drill bit, on a machine tool, for example, a core drill, including an output shaft for transmitting a torque generated in the machine tool to the tool; and a union nut positioned around the output shaft for detachably connecting the output shaft to an attachment end of the tool. The output shaft includes a locking ring and the union nut includes a washer disk, as well as an attenuator, the washer disk being positioned between the locking ring and the attenuator.

Abstract: A drive shaft for a machine tool is connectable to a drilling tool. The drive shaft contains a cavity extending substantially over the entire length of the drive shaft and along the axis of rotation where the cavity contains an inflow opening through which water can be fed along the drive shaft into the drilling tool. An insert device is provided in the cavity, through which, to cool the drive shaft, the water is guided first in a first direction and then in a second direction where the insert device contains a first curved guide element and a second curved guide element for separating the water which is guided in the first direction from the water which is guided in the second direction. The cross-sectional area of the first curved guide element is designed point-symmetrically about a center longitudinal axis to the cross-sectional area of the second curved guide element.

Abstract: A gear wheel for a transmission, in particular a draw key transmission, is disclosed. The gear wheel contains a first ring element and a second ring element, the first ring element having a driving contour for receiving a shaft pin of the transmission and the second ring element having a toothing on an outer surface.

Abstract: A device for holding and securing a tool, in particular, a drill bit, on a machine tool, for example, a core drill, including an output shaft for transmitting a torque generated in the machine tool to the tool; and a union nut positioned around the output shaft for detachably connecting the output shaft to an attachment end of the tool. The output shaft includes a locking ring and the union nut includes a washer disk, as well as an attenuator, the washer disk being positioned between the locking ring and the attenuator.

Abstract: A drive shaft for a machine tool, for example a core drilling machine, able to be connected to a drilling tool, in particular a core bit, is disclosed. The drive shaft contains a cavity which substantially extends over the whole length of the drive shaft and along the rotational axis. The cavity contains at least one inflow opening where, through the at least one inflow opening, water can be fed along the drive shaft into the drilling tool. In the drive shaft, an insertion device is provided in the cavity, through which water is guided for cooling the drive shaft, firstly, in a first direction and then in a second direction, where the water comes into direct contact with the inner side of the cavity at least in the first direction.

Abstract: A drill stand for a core drilling machine (1) for driving an annular core bit (2) rotatable about a rotational axis (A) has a base plate formed of a post plate (3) and a vacuum plate (6) securable with each other with a possibility of displacement relative to each other in a plane (E) separating the post and vacuum plates (3,6), at least one post (5), an attachment element (4) for securing the post (5) on the post plate (3); and a vacuum planar attachment element (7) for mounting the base plate on a surface.

Abstract: A drill stand for a core drilling machine (1) for driving an annular core bit (2) rotatable about a rotational axis (A) has a base plate formed of a post plate (3) and a vacuum plate (6) securable with each other with a possibility of displacement relative to each other in a plane (E) separating the post and vacuum plates (3,6), at least one post (5), an attachment element (4) for securing the post (5) on the post plate (3); and a vacuum planar attachment element (7) for mounting the base plate on a surface