Writing instrument with anti-broken core mechanism

Abstract

The present invention provides a writing tool with the function of preventing broken core. When writing, when excessive pen pressure acts on the tip of the core, regardless of the pressing force based on the excessive pen pressure, the sliding part will advance to protect the core. core. On the outer periphery of the main body, a gripping portion (4) is provided in a manner capable of moving in the shaft diameter direction and the shaft length direction, and is biased in the backward direction by a retreat spring (29). The front end of the grip part can move along the axial length direction and abuts against the top abutment piece (22), and the push piece (30) compresses the retreat spring (29) through the top abutment piece. The slider (6) has a spring support portion (39) to which a biasing force of a retreat spring acts indirectly or directly so as to be biased in a backward direction by the retreat spring. When the backward spring is compressed, a moving space is formed between the backward spring and the spring supporting part, and the slider advances along the moving space by the forward spring (40) or the weight of the slider to protect the top end of the core.

Description

technical field [0001] The present invention relates to a writing implement with a core breakage prevention mechanism that prevents core breakage when excessive pen pressure is applied. Background technique [0002] Among writing implements such as mechanical pencils, there is known a writing implement with a core breakage prevention mechanism: when excessive pen pressure acts, the core holding portion protruding from the top end of the barrel is advanced to protect the core, so that The core does not break (see, for example, Patent Document 1). The writing instrument described in Patent Document 1 is configured such that when the shaft cylinder is tilted under a large pen pressure, the core holding part is pushed forward by a force applied along the shaft diameter direction of the shaft cylinder, and the tip of the core holding part is advanced. to the outer periphery of the core to cover the core. At this time, a large pressing force caused by excessive writing pressure ...

AI Technical Summary

Problems solved by technology

However, since the mechanical pencil described in Patent Document 2 is configured to distort the grip portion and move the lead delivery unit axially rearward when excessive pen pressure acts, in such a mechanical pencil, the The writing core delivery unit suddenly retreats and the core sinks, the writing operation is interrupted, and it is difficult to use

[0004] In addition, in the mechanical pencil described in Patent Document 3, when the front shaft is skewed with respect to the rear shaft, the lead delivery unit advances. The pressure is used to make the core delivery unit advance directly and push the metal mouth to the paper surface, which may damage the paper surface, etc.

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