Abstract: A folding knife may include a blade, a handle and a bearing located within the handle. In one embodiment, the bearing may include a first donut-shaped ring unit disposed adjacent to a blade through hole on one side of the blade and a second ring unit disposed adjacent to the blade through hole on the other side of the blade. A plurality of protruding units facing the blade are disposed on an outer surface of the first ring unit and second ring unit. The blade has a plurality of positioning protrusions surrounding the blade through hole on both sides of the blade corresponding to the protruding units, and the movement and position of the blade can be determined by relative positions between the positioning protrusions and the protruding units. Thus, the movement of the blade can be easily controlled and managed by the force exerted by the user.

Abstract: The present invention relates to an arc fault detection apparatus using a microcomputer, which divides current paths into a low current path and a high current path depending on the intensity of load current using a source voltage that is applied to a lead wire and determines whether an arc fault signal exists, and which presets a circuit breaking time against the generation of an arc, corresponding to the magnitude of a load, and immediately breaks a circuit if a corresponding arc fault signal is detected within the preset circuit breaking time.

Abstract: Disclosed herein is a circuit for preventing a malfunction of an arc fault detection device for determining whether an arc fault occurs through a low-current route or a high-current route, classified according to the magnitude of load current, using a source voltage applied to a conductor, which sets an operational prohibition range so as to prevent the malfunction of determining a pseudo-arc signal attributable to various combinations of loads to be an actual arc signal and interrupting a circuit, thus being capable of more precisely controlling the detection of the arc signal.

Abstract: Disclosed herein is an apparatus for detecting an arc fault, which prevents a malfunction caused by a conventional current detecting method by detecting a source voltage applied onto a conductive wire to determine whether there is an arc fault, prevents a malfunction with respect to a pseudo arc signal by dividing a current detecting route into two according to the magnitude of a load current occurring onto the conductive wire to determine whether there is the arc fault by voltage detection, and lessens the danger of a fire by reducing a circuit break time according to the magnitude of the load current. A voltage detector detects the arc fault by use of two detecting routes. Each route differs in a filtering value of a filter, presence/absence of level limit, an amplification factor of an amplifier, an accumulation value of a comparator, etc. according to the magnitude of a load current occurring on a conductive wire, thereby reducing a circuit break time.