Micro Co., Ltd.

Yasuhiro Sanpei

Hiroyuki Kanari

An automatic mechanical pencil has a tubular piece removably connected to a barrel cylinder, and a slider for frictionally holding a lead and being movably disposed in a front portion of the tubular piece. A lead chuck is disposed in the barrel cylinder for releasably holding the lead so as to allow forward movement of the lead but prevent backward movement thereof. A first spring urges the slider forward and the lead chuck backward so that when a writing front end of the writing instrument is released from a writing surface, the lead is automatically fed by urging the slider forward. A lead reservoir is disposed rearwardly of the lead chuck to supply the lead to the lead chuck. The lead reservoir has a reservoir main body, a pipe holder connected to a front end of the reservoir main body and having a guide projection, and a stopper disposed around an outer periphery of the pipe holder and having a receiving groove engageable with the guide projection. A second spring urges the reservoir main body and the stopper of the lead reservoir so that the reservoir main body and the stopper move relatively in the axial direction of the barrel cylinder.

Automatic mechanical pencil and method of assembly thereof

A writing instrument is capable of functioning both as an automatic mechanical pencil and as a shaking-type mechanical pencil. The writing instrument has a barrel cylinder constituted by a front cylinder detachably connected to a rear cylinder. A slider is disposed at the front end of the barrel cylinder, and a lead chuck, such as a ball chuck, is disposed rearwardly of the slider. A slider spring urges the slider forward and urges the lead chuck rearward. A lead reservoir is movably disposed rearwardly of the lead chuck. Around the outer periphery of the lead reservoir, a weight is disposed to undergo back-and-forth movement in an axial direction. On the outer periphery of the lead reservoir is disposed a weight-receiving cylinder against which the rear end of the weight abuts when the writing instrument is shaken. A knocking spring urges the weight-receiving cylinder forward and urges the lead reservoir rearward.

Growing community of inventors

Fukushima-ken, Japan

Yasuhiro Sanpei