There are many risks in using grass cutter because of the pebble in grass and high speed rpm when the cutter hits the hard objects in grass. In this study, the existing patents are surveyed and classified for the new mechanism about the bottom safety cover. The new mechanism was modelled and the planetary gear are designed. The power source (engine or motor) will rotate the sun gear and the carrier of planetary gear is fixed into handle frame. The ring gear will drive the final cutter. The carrier fixed the bottom safety cover through the planetary gear hole at the handle bar. In this paper, we develop a new mechanism and analyze the idea for safe grass cutter and investigate the possibility of having patent through patent search.

Driving mechanism, the central part of a robot, was designed in this study. Power for the motive drive was acquired by directly connecting the motor shaft in worm shape of the low-end DC motor, car window motor, to a decelerator. The decelerator consists of a worm gear to receive power from the motor shaft, a pinion gear to be connected in line with the worm gear, and an output shaft to be engaged to the pinion gear. Motion driving is achieved by the power from the motor shaft with the designed gears, transferred to the deceleration mechanism and to the output gear

World Widely, a lot of gearboxes are being developed for the increase of fuel efficiency. Among them, CVT has an infinite gear and shifts gear at the best situation which makes it have no impact by changing speed and reduce the expense of fuel. We designed and manufactured 2ranked gearbox for V-belt similar to CVT. We studied an energy generated when it is functioning and had an experiment of forwarding power of it. These studies are planned to find out its functions and the efficiency of forwarding power of it.