Apparatus, systems, and/or methods for adjusting belt tension in a material removal machine are disclosed. In some examples, the material removal machine includes a material removal tool secured on a spindle. A spindle pulley may be secured to the spindle, such that rotation of the spindle pulley causes the material removal tool to be rotated via the spindle. The material removal machine may further include a movable hub that retains the spindle, such that movement of the hub translated into movement of the spindle. Because the spindle pulley is securely attached to the spindle, movement of the hub may translate into movement of the spindle pulley. This movement of the spindle pulley may change a distance between the spindle pulley and an actuator pulley, thereby changing the tension in a belt connecting the spindle pulley and the actuator pulley.

Provided is a rotary tool. In the rotary tool, the rotating tip tool is mounted on a spindle by the fixture, and the spindle and the tip tool are rotated by a motor. The rotary tool has a switch which can switch the motor between a rotation state and a stop state, and a control device which controls the rotation of the motor corresponding to the operation of the switch. When the switch is turned off after a required time T elapses after the motor is started, the control device stops the rotary tool (104d, 106d) by performing a common braking operation on the spindle, and when the switch is turned off before the required time T elapses after the motor is started, the control device stops the tip tool (101d) by inertia without applying a braking force.

The invention refers to a hand-held and hand-guided motor driven polishing or sanding tool (2). The tool (2) has a tool housing (4) and a motor (6; 62) located therein. The tool (2) further has a polishing or sanding working element (8) attached to a tool shaft (10) of the tool (2). The motor (6; 62) is adapted to drive the tool shaft (10) in a first direction of rotation (12).

It is suggested that the tool (2) is equipped with a switch (44) for changing the sense of rotation of the tool shaft (10) between the first direction of rotation (12) and a second direction of rotation (42) opposite to the first direction of rotation (12).

A machine (100) for processing a concrete surface, the machine comprising a control unit (101) and at least three tool carriers (110) arranged to rotate about respective tool carrier axes, wherein at least one of the tool carriers (110) is arranged to generate a variable force acting on the machine, relative to the concrete surface, in response to a control signal generated by the control unit (101), wherein the control signal is configured to provide locomotion by the machine relative to the surface.

A machining assistance system for assisting a machining apparatus includes: a workpiece supporting force generating unit, which generates workpiece supporting force against machining reaction force that is exerted on a machining portion of a workpiece by a working tool; a supporting device, which moves the supporting force generating unit while supporting the supporting force generating unit; and a workpiece supporting force control device, which controls operation of the workpiece supporting force generating unit and operation of the supporting device based on machining reaction force related data related to the machining reaction force and machining position related data related to a machining position of the working tool, such that the workpiece supporting force generating unit exerts the workpiece supporting force on the workpiece against the machining reaction force.

A portable abrading machine includes an abrading-machine main body, a battery holster, and a power-supply cord. The abrading-machine main body includes a main-body housing, which houses a motor, and an abrading part, which is configured to move with orbital motion when a motor shaft of the motor is rotated. The battery holster includes a battery-mounting part, on which a battery is mountable. The power-supply cord is configured to supply electric power from the battery, when mounted on the battery-mounting part, to the abrading-machine main body. The power-supply cord connects the abrading-machine main body and the battery holster without going through the housing.

An electric tool grinding machine has an electric motor, a grip body, a cover connected to the body, an eccentric block in the cover and driven by the motor, and an airflow generating member attaching on the block. The body has at least one air hole having a first distance relative to an axis of the motor, the cover doesn't have a vent hole, the airflow generating member has a bottom plate and a plurality of fan blades, a second distance is between a top edge of the blade and the body, a third distance is between an outer edge of the blade and the cover, the second distance is at least 50% of a longitudinal length of the blade, the third distance is at least 50% of a radial length of the blade, and an outer diameter of the airflow generating member is greater than the first distance.

An electric tool grinding machine has an electric motor, a grip body, a cover connected to the body, an eccentric block in the cover and driven by the motor, and an airflow generating member attaching on the block. The body has at least one air hole having a first distance relative to an axis of the motor, the cover doesn't have a vent hole, the airflow generating member has a bottom plate and a plurality of fan blades, a second distance is between a top edge of the blade and the body, a third distance is between an outer edge of the blade and the cover, the second distance is at least 50% of a longitudinal length of the blade, the third distance is at least 50% of a radial length of the blade, and an outer diameter of the airflow generating member is greater than the first distance.

An electric tool grinding machine and a grinding disc cover thereof, the machine includes a grip body, an electric motor, a grinding disc, and an airflow generating member. When the motor rotates, the member forms a heat dissipation airflow in the grip body. The grinding disc cover is assembled with the grip body and covers the member therein. The grinding disc cover includes a cover body, an assembly port, and a release port facing the grinding disc, the cover body does not have a vent hole other than the assembly and release ports, when the release port is viewed from the assembly port toward the release port, an inner wall of the release port has a flow guiding section, an air outlet section with a slope different from that of the flow guiding section, and an arcuate diversion section connecting between the flow guiding and air outlet sections.

An electric tool grinding machine and a grinding disc cover thereof, the machine includes a grip body, an electric motor, a grinding disc, and an airflow generating member. When the motor rotates, the member forms a heat dissipation airflow in the grip body. The grinding disc cover is assembled with the grip body and covers the member therein. The grinding disc cover includes a cover body, an assembly port, and a release port facing the grinding disc, the cover body does not have a vent hole other than the assembly and release ports, when the release port is viewed from the assembly port toward the release port, an inner wall of the release port has a flow guiding section, an air outlet section with a slope different from that of the flow guiding section, and an arcuate diversion section connecting between the flow guiding and air outlet sections.