Abstract: Provided is a heater for an aerosol-generating device including a first electrically conductive pattern configured to perform heating and a second electrically conductive pattern arranged in parallel with the first electrically conductive pattern. The first electrically conductive pattern and/or the second electrically conductive pattern may include a material having a relatively small resistance temperature coefficient. Accordingly, a temperature increase rate of the heater may be greatly improved.

Abstract: The present invention relates to a grinding wheel assembly usable in a polishing machine for finishing a surface or floor, and more particularly, to a grinding wheel assembly for facilitating attachment and detachment of a grinding tool, capable of preventing damage to the grinding tool caused by centrifugal and frictional force produced by high speed rotation, and which reduces working time and enables convenient use due to easy replacement of the grinding tool. The grinding wheel assembly includes a ferromagnetic grinding tool, and a disk-shaped grinding wheel including a tool mounting part with a recess shape sized for mounting the grinding tool and a magnet embedded in one side. When required, a protruding separation prevention pin is provided to stably mount the grinding to the tool mounting part and a push injector pin is provided to facilitate attachment and detachment of the grinding tool.

Abstract: A vacuum cyclone dust collector according to the present invention comprises an upper housing through which an absorption hole and a discharging hole are formed and inside which air is inputted and discharged, a lower housing which induces air, which is inputted inside the upper housing through the absorption hole, to be circulated and is connected detachably to the lower part of the upper housing, and air refining part which is arranged rotatably to the upper part of the upper housing with keeping a vacuum state and allows air being inputted through the absorption hole to be circulated inside the upper housing and the lower housing and fine dust and impurities contained in air being inputted through the absorption hole to be dropped downward and refined air without fine dust and impurities to be discharged through the discharging hole.