A grinding machine tool comprises a housing, a driving assembly disposed in the housing, a grinding disc driven by the driving assembly, and having a grinding surface and a non-grinding surface, a switch driving the driving assembly, and a pressing plate disposed on the housing and having a first state in which the switch drives the driving assembly to drive the grinding disc when the pressing plate is operated, and a second state in which the switch stops driving the driving assembly when the pressing plate is not operated. The grinding machine tool has a grinding disc braking structure detached from the non-grinding surface when the pressing plate is in the first state; when the pressing plate is in the second state, the grinding disc braking structure moves toward the non-grinding surface and contacts with the grinding disc to stop the grinding disc from rotating.

An electric tool grinding machine includes an electric motor, an airflow generating member, and a casing. The casing includes a hollow shell, a motor housing located in the hollow shell, two partitioning plates located between a side wall of the motor housing and the hollow shell, at least one air outlet facing the airflow generating member, a first air inlet formed on the hollow shell, and at least one second air inlet formed on the hollow shell and spaced apart from the first air inlet. When the airflow generating member is activated, the first air inlet generates a pressure difference in the hollow shell near an air inlet portion of the motor housing to cause air to be drawn into the second air inlet.

An electric tool grinding machine includes an electric motor, an airflow generating member, and a casing. The casing includes a hollow shell, a motor housing located in the hollow shell, two partitioning plates located between a side wall of the motor housing and the hollow shell, at least one air outlet facing the airflow generating member, a first air inlet formed on the hollow shell, and at least one second air inlet formed on the hollow shell and spaced apart from the first air inlet. When the airflow generating member is activated, the first air inlet generates a pressure difference in the hollow shell near an air inlet portion of the motor housing to cause air to be drawn into the second air inlet.

A roller assembly for sharpening a knife, comprising a cylindrical body and a plurality of surface treatment sections positioned on a first lateral side and a second lateral side of the cylindrical body. Each surface treatment section coupled with the cylindrical body through individual one or more connecting elements. Each surface treatment section providing different degrees of surface treatment to the target surface including coarse grinding, fine grinding, buffing and honing. The two guide elements rotate in synchronization with a sliding movement of the roller assembly along a pitch axis of the cylindrical body. The roller assembly is adapted to provide various surface treatment to sharpening objects.

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.

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 brush assembly has a brush holder rotatable about a rotation axis, a ring brush carried on the holder and having an annular array of radially outwardly projecting bristles, and a stop element fixed adjacent the ring brush, of noncircular section. This stop element extends along and is rotatable about a longitudinal axis generally parallel to the rotation axis and projects into the array of bristles.

Heat generated during braking is reduced to prevent reduction in braking performance or the service life of the components. A grinder includes a housing, an operable member, a switch operable to be turned on or off in response to an operation on the operable member, a rotational shaft rotatable in response to an operation for turning on the switch, and a brake assembly that applies braking to the rotational shaft with the switch being in an off state and to release the braking applied to the rotational shaft in response to an operation for turning on the switch performed by the operable member. The brake assembly includes a brake member being circular and fixed to the rotational shaft, and multiple pressing members that press the brake member at multiple positions to apply a uniform force to the brake member from radially outward positions toward a center of the brake member.

Heat generated during braking is reduced to prevent reduction in braking performance or the service life of the components. A grinder includes a housing, an operable member, a switch operable to be turned on or off in response to an operation on the operable member, a rotational shaft rotatable in response to an operation for turning on the switch, and a brake assembly that applies braking to the rotational shaft with the switch being in an off state and to release the braking applied to the rotational shaft in response to an operation for turning on the switch performed by the operable member. The brake assembly includes a brake member being circular and fixed to the rotational shaft, and multiple pressing members that press the brake member at multiple positions to apply a uniform force to the brake member from radially outward positions toward a center of the brake member.

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 through 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.