A safety braking device for a machine tool for braking a processing tool driven by an electric motor via an output unit, more particularly an output shaft, includes at least one braking device which is provided to halt rotation of the output unit in a braking process. The braking device has at least a first braking stage and a second braking stage. The disclosure further relates to a machine tool having the safety braking device and to a method for operating a safety braking device.

An emergency tool stop device is provided. The device may be attached to any existing grinder and has a guard that partially encircles at least one cutting/grinding blade and incorporates a fastener mechanism for attaching components such as a disk brake, washer, cutting blade, and retaining nut. The washer prevents the brake from pressing on the blade, while the nut secures the assembly to the guard. Furthermore, the device is equipped with a brake lever that attaches to the grinder's handle with a fastener and connects to a brake pad via a cable. While using the grinder, the lever can be depressed while a user grips the handle of the grinder where the lever is installed. Once released (i.e., in the event of a drop) the lever activates the brake pad which stops the blade's rotation by bringing the brake pad into contact with the blade.

A powered fastener driver includes a housing, a cylinder within the housing, the cylinder containing a pressurized gas, a piston within the cylinder and movable from a top-dead-center position to a bottom-dead-center position, a driver blade movably coupled to the piston, a lifter, a drive unit configured to provide torque to the lifter, and a sensor. The driver blade has a plurality of teeth. The sensor is configured to detect one or more of the plurality of teeth and a controller in communication with the drive unit and the sensor. The controller is configured to count a number of the plurality of teeth detected by the sensor, compare the number of detected teeth to a predetermined number of teeth, and stop the drive unit when the number of detected teeth is less than the predetermined number of teeth.

A method for starting a machine tool includes receiving at least one start signal; outputting, after the start signal has been received, at least one acoustic and/or visual warning signal; monitoring, by at least one sensor system, at least one safety zone of the machine tool; and starting the machine tool at the earliest after a predetermined delay time after the start signal is received. The start of the machine is aborted if a hazard is detected by the sensor system.

An electric working machine in one aspect of the present disclosure includes: a motor; a driver to drive the motor; a first control circuit; and a second control circuit. The first control circuit controls the driver such that the motor rotates in a set rotation direction. The second control circuit is provided separately from the first control circuit. The second control circuit detects a rotation direction of the motor and performs an abnormality handling process to stop rotation of the motor in response to a situation where the detected rotation direction is reverse to the set rotation direction.

A power tool and methods are provided for detecting objects (e.g., flesh or other materials) in the operating path of a power tool's output component (e.g., saw blade or drill bit). An object detection sensor in the power tool generates an output signal indicative of a type of material detected in the operating path of the power tool. A power tool controller receives the object detection sensor output and determines when a material in the operating path of the power tool changes. The controller changes operation of a motor of the power tool (e.g., increasing or decreasing speed or stopping the motor) in response to the detected material change. The object detection sensor may include, for example, an RF sensor, a capacitive sensor, a camera, a conductivity probe, or an ultrasound probe.

A machine operator holds a chicken carcass to a circular saw, or a casting to an abrasive cut off wheel. Considerable risk to the hands is minimised with a controllable (about 10 ms) wheel stop mechanism, optically triggered when a gloved finger enters a hazardous zone. (An option uses a conductive glove trigger). An electromagnet releases a powerful spring mechanically linked to opposing brake shoes, forcing them against both sides of a brake disc. The brake disc and the cutting wheel share a shaft but are located in separate compartments. Incident reporting over a network is included.

An emergency braking assembly for a motor-driven tool has a holding structure, a braking element movably mounted on the holding structure, and a wire-like actuation element, which has a shape-memory alloy. A first end of the actuation element is attached to the holding structure. A second end of the actuation element is drivingly coupled to the braking element. A method operates the emergency braking assembly. The braking element is set in motion by the actuation element and then a motion coupling between actuation element and braking element is cancelled or terminated.