A method for determining a recommendation of a gear to be engaged for a core drill. In the method, it is possible to use for example a drop in a rotational speed of a core bit of the core drill in the event of sudden deactivation of the motor of the core drill in order to determine the diameter of the core bit. Alternatively, the diameter of the core bit can be determined when the drill is started up or turned on. The diameter of the core bit is then used as the basis for the recommendation of the gear to be engaged. In a second aspect, the invention relates to a core drill with which the method can be carried out.

A method to control a power tool, especially a core drill, including a motor as the drive for the power tool, a control unit, a power display, a transmission having at least a first gear and a second gear, a first sensor to detect the rotational speed of at least one component of the transmission and a second sensor to detect the rotational speed of the motor. The method includes the following steps: ascertaining a first rotational speed of the at least one component of the transmission when the transmission has been put into a gear, ascertaining a first rotational speed of the motor when the transmission has been put into a gear, ascertaining the selection of the gear on the basis of a first prescribed ratio of the first rotational speed of the at least one component of the transmission and of the first rotational speed of the motor on the basis of a look-up table, and setting the limit value of the power display on the basis of the look-up table as a function of the gear that has been selected. A power tool for purposes of using the method.

A method for detecting whether a slip clutch release event has taken place in a power tool includes determining a first speed of a gear device by a first sensor, determining a second speed of a motor by a second sensor, and determining a current value by a third sensor. The method further includes determining a state of the power tool by using the first and second speeds and the current value, determining a state of the gear device in dependence on the current value by a control device, ascertaining a state of activity of the slip clutch in dependence on the first and second speeds by the control device, and ascertaining by the control device by a combination of the state of the gear device and the state of activity of the slip clutch whether the slip clutch release event has taken place.

A machine tool is configured to receive input data defining a profile to be machined onto a workpiece, with the profile defined in a plane perpendicular to an axis of rotation of the workpiece and non-circular in that plane, and calculate using an evolutionary algorithm a workpiece velocity profile corresponding to the velocities at which the workpiece is to be rotated by the workpiece mount over at least part of a rotation of the workpiece during machining. The machine tool then rotates the workpiece according to the workpiece velocity profile during machining of the workpiece.

A control method for using a core drilling system is disclosed. In an embodiment the method includes detecting a predetermined drilling situation on the basis of the attainment of a predetermined threshold value for at least one predetermined corresponding drilling parameter and ending the core drilling operation by selecting a reverse-travel mode for removing the drilling tool from the borehole if the advancing device does not reach a predetermined threshold value for a predetermined corresponding distance value in a direction and the core drilling machine does not reach a predetermined threshold value for at least one predetermined corresponding drilling parameter or continuing the core drilling operation by selecting a predetermined operating mode if the advancing device reaches a predetermined threshold value for a predetermined corresponding distance value in a direction and the core drilling machine reaches a predetermined threshold value for at least one predetermined corresponding drilling parameter.

An electrically controllable rotary pressure device includes a rotary pressure means for being inserted to a human body structure to bore a hole therein or to be fastened thereto, a motor for generating torque provided to the rotary pressure means, a power control unit for supplying power to the motor, a central processing unit for controlling the power control unit, a rotational speed sensor for measuring a rotational speed of the motor or the rotary pressure means, a current sensor for measuring a current flowing into the motor, and a torque compensation unit for adjusting the torque by adjusting a control signal from the central processing unit to the power control unit based on the measured current.

According to one aspect of the present invention, there is provided an electrically controllable rotary pressure device, comprising: a motor for providing torque to rotary pressure means; a power control unit for supplying power to the motor; a central processing unit for controlling the power control unit; and a rotational speed sensor for measuring a rotational speed of the motor or the rotary pressure means, wherein the central processing unit comprises an abnormality detection unit for receiving the rotational speed from the rotational speed sensor, and wherein the abnormality detection unit transmits a control signal to the central processing unit when abnormality in the rotational speed is detected, so that the central processing unit interrupts the power supply of the power control unit.

A control method for the use of a core drilling system including a core drill and a feed device for driving the core drill along a machine holding device. The method includes the steps of determining the end of a core drilling operation on the basis of reaching a predetermined threshold value for at least one corresponding predefined drilling parameter; and of selecting a reversing mode for retracting a drilling tool out of a borehole at a reversing rotational speed which corresponds to a multiple of a predetermined tapping rotational speed of the drilling tool at the beginning of the core drilling operation.

A material for assisting metal machining process, having a polymer compound, wherein a content of the polymer compound is 50% by mass or more based on the total amount of the material for assisting metal machining process, a melting point is 40? C. or more, and a temperature at 5% weight loss is 275? C. or more.

A method to control a power tool, especially a core drill, including a motor as the drive for the power tool, a control unit, a power display, a transmission having at least a first gear and a second gear, a first sensor to detect the rotational speed of at least one component of the transmission and a second sensor to detect the rotational speed of the motor. The method includes the following steps: ascertaining a first rotational speed of the at least one component of the transmission when the transmission has been put into a gear, ascertaining a first rotational speed of the motor when the transmission has been put into a gear, ascertaining the selection of the gear on the basis of a first prescribed ratio of the first rotational speed of the at least one component of the transmission and of the first rotational speed of the motor on the basis of a look-up table, and setting the limit value of the power display on the basis of the look-up table as a function of the gear that has been selected. A power tool for purposes of using the method.