| 摘要 |
The invention discloses a saving pencil capable of being prolonged infinitely. A section of 2-4 cm long trapezoidal threads is arranged at each of the two ends of the pencil, the outer diameter of the threads is smaller than the diameter of the pencil by 0.2-2 mm, a stopping groove is formed in the middle section of the threads, one threaded end of the pencil is provided with a connecting piece in screw driving connection with the pencil, the lead angle of internal threads of the connecting piece and the lead angle of external threads of the end of the pencil are smaller than an equivalent friction angle, a pair of elastic clamp springs with one ends fixed and the other ends moving freely is arranged on the opposite portions of the two ends of the connecting piece, when the connecting piece moves, a clamp fastener is clamped to the stopping groove for location. When a leftover pencil cannot be held for writing, the threaded end of another pencil is screwed into the connecting piece, the length of the leftover pencil is increased so that the leftover pencil can be held for writing, the utilization rate of the pencil is improved, waste is reduced, and resources are saved. |
