The self-propelled construction machine, in particular road-milling machine, recycler, stabiliser or surface miner, comprises a machine frame 2, which is supported by a chassis 1, which has wheels or tracks 1A, 1B. A milling drum 4 is arranged on the machine frame. The wheels or tracks 1A, 1B and the milling drum 4 are driven by a drive unit 8. Furthermore, the construction machine comprises a control unit 19 for controlling the drive unit 8 and a signal-receiving unit 18 for detecting at least one measurement variable M(t) which is characteristic of an operating state of the milling drum 4. The construction machine is characterised in that the rotational speed of the milling drum 4 is adapted, on the basis of at least one measurement variable M(t) which is characteristic of a critical operating state of the milling drum, to the operating conditions of the construction machine in such a way that the milling drum is operated in a non-critical operating state. The adaptive open-loop control of the milling drum rotational speed allows the construction machine to be operated at an optimum operating point with respect to the milling drum rotational speed.

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.

A method for operating a machine tool that includes an electric motor for driving a drilling tool and an open- and closed-loop controller for open- and closed loop control of the motor power. The method includes: operating the machine tool in a tapping mode at a first rotational speed value, where the first rotational speed value is lower than a predetermined idling speed value of the electric motor; detecting a predetermined first threshold value for the motor current; reducing the motor current to a predetermined second threshold value when the first threshold value is exceeded; operating the machine tool at a second rotational speed value, where the second rotational speed value is lower than the first rotational speed value; operating the electric motor at a predetermined motor current value; and operating the controller for closed loop control of the motor power via the motor current with an oscillating action.

In a self-propelled construction machine (1), in particular road milling machine, recycler, stabilizer or surface miner, comprising a machine frame (4), at least two travelling devices (2), at least one hydraulic drive system (50) for driving at least two travelling devices (2), at least one working device, in particular a milling drum (6), for working the ground pavement (3), it is provided for the following features to be achieved: a detection device (44, 60, 62) is provided which detects fluctuations in the longitudinal speed (v.sub.act) of the construction machine (1) during movement of the construction machine (1), wherein a control unit (38) controls the hydraulic drive system (50) as a function of the detected fluctuations in such a fashion that the drive speed (v.sub.drive) for driving the travelling devices (2) specified by means of the hydraulic drive system (50) is continuously adjusted so that the detected fluctuations are reduced or compensated for.

A hand-held electrically powered cut-off tool (100) for cutting concrete and stone by a rotatable cutting disc (105), the cut-off tool (100) comprising an electric motor (130) arranged to be controlled by a control unit (110) via a motor control interface (120), wherein the control unit (110) is arranged to obtain data indicative of an angular velocity of the cutting disc (105), and to detect a kickback condition based on a decrease in angular velocity, wherein the control unit (110) is arranged to control an electromagnetic braking of the electric motor (130) in response to detecting a kickback condition, wherein the control unit (110) is arranged to determine an angular acceleration associated with the electric motor (130), and to detect the kickback condition based on a comparison between the determined angular acceleration and a configurable detection threshold.

A floor saw (100) for sawing in a concrete surface segment (160), the floor saw comprising a circular cutting blade (110), at least two drive wheels (120) arranged to support the floor saw on the concrete surface segment (160), a sensor arrangement (140) configured to determine a current yaw motion of the floor saw, and a control unit (130) configured to receive a desired yaw motion setting, wherein the at least two drive wheels (120) are arranged to be driven at respective first and second wheel speeds, and wherein the control unit (130) is arranged to control a difference between the first and second wheel speeds to reduce a difference between the current yaw motion of the floor saw and the desired yaw motion setting.

Tool bodies, tools and machines for operating the tool include electronic circuits for providing data, collecting data, analyzing data and for controlling machines based on such data. Tool bodies and tools may include electronic circuits having data collecting sensors, which may be embedded in a housing with the electronic circuit and/or positioned outside of such a housing. Sensors include temperature sensors, motion sensors, strain sensors, moisture sensors, electrical resistance sensors, position sensors, antennas, and other components.

The present application provides a residual material removing device, method and system, in which the residual material removing device includes: a loading platform configured to support a material to be cut; a fixing plate abutting against an upper surface of the material to be cut is configured to fix the material to be cut, and one end of the fixing plate is in contact with a residual material in the material to be cut; a first pressing portion in contact with one end of the fixing plate is configured to apply pressing force to one end of the fixing plate to separate the residual material from the material to be cut under the action of the pressing force.

A drilling tool includes: a drive source; a bit attachment portion to which an end bit is attachable; a power transmission portion configured to apply a motive force to the end bit attached to the bit attachment portion; an operation portion switchable between an ON-state and an OFF-state by a manual operation and configured to receive a setting operation for setting a stop condition; and a controller configured to set the stop condition based on the setting operation, and to start driving of the drive source in response to a first switching operation for switching the operation portion from the OFF-state to the ON-state. In a state where the stop condition is set, even when the operation portion is in the ON-state, the controller stops driving of the drive source in response to the stop condition being met while the drive source is being driven.

Disclosed is a machine for forming saw cuts into sidewalk concrete slabs, the machine comprising a frame, rubber tracks attached to the underside of the frame to self-propel the machine in a travel direction along a sidewalk during use, and a cutting assembly mounted to the frame. The cutting assembly comprises a saw for forming saw cuts, a linear actuator for moving the saw at a depth into the sidewalk, and a screw drive motor to move the saw to form the saw cut in a direction perpendicular to the travel direction. While road repair machinery has the luxury of more space, machines for sidewalks are smaller and tighter. The machine in accordance with the teachings of this invention uses a newly designed cutting assembly to keep the size of the machine useable for sawcuts in sidewalks.