JPH079676Y2 - Drawing head of automatic drafting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an image drawing head of an automatic drafting machine.

[Prior art and its problems] Whenever the lead core is consumed with writing, the lead core is automatically pushed down according to the wear as compared with the conventional drawing head in which the lead core is pushed down in the axial direction and extended. In recent years, drawing line heads that have been extended have been attracting attention due to their ease of operation.
However, on the other hand, due to the increase in the writing speed of machines and the widespread use of various types of drawing paper, the contact portion of the drawing head on the paper surface is likely to be worn and the life of the drawing head is shortened. In order to eliminate this problem, a stainless steel pipe is press-fitted onto the inner surface of the slider, surface treatment such as nickel and chrome is applied, and the corner of the slider tip is chamfered to reduce the friction resistance with the paper surface. Had been reduced. However, in both of these, burrs are apt to occur on the inner surface of the slider or the like at the time of creation, and these burrs cause a decrease in writing pressure depending on the writing direction, which makes it easy for shading to appear on the writing line. .

[Means for Solving the Problems] The present invention has been made to solve the above problems, and the gist thereof is to allow the lead core to move forward, but to prevent the lead core from moving backward by a wedge action. In a drawing head in which a ball chuck mechanism is arranged in a holder, and a slider having a holding member in front of the ball-jack mechanism is slidably arranged by being urged forward by an elastic member, The drawing head of an automatic drafting machine is characterized in that a curved surface portion is provided at least in the tip end surface of the core insertion hole.

[Examples] Hereinafter, examples will be described in more detail with reference to the accompanying drawings.

As shown in FIG. 1, the ball chuck mechanism 1 allows the lead core 1 to move forward, but prevents the lead core 1 from moving backward by a wedge action.
Is placed in the holder 2, and the slider 4 having the holding member 3 in front of the holder is attached to the elastic member 5 such as a spring.
It is arranged so as to be elastic and slidable. A curved surface portion 6 is formed on the outer surface and the inner surface of the slider 4 at the tip thereof. The curved surface portion may be formed at least on the inner surface, and may be appropriately subjected to abrasion-resistant surface treatment.

Next, the operation will be described.

By writing while the front end face 7 of the drawing head is pressed perpendicularly to the paper surface, the stiffer 4 is retracted according to the wear of the lead core 1, and the elastic force of the elastic member 5 is released by releasing the pressing. The lead member 1 is pulled out from the ball chuck mechanism 1 by the holding member 3 of the slider 4 which is moved forward and returned while being flush with the front end face 7.

ADVANTAGES OF THE INVENTION According to the present invention, a ball chuck mechanism that allows the lead core to move forward but prevents the lead core from moving backward by a wedge action is arranged in the holder and is held in front of the ball chuck mechanism. In a drawing head in which a slider having a member is biased forward by an elastic member to be slidably arranged,
Since a curved surface portion is provided on at least the inner surface of the tip of the core insertion hole of the slider tip portion, not only the friction resistance with the paper surface but also the friction resistance with the lead core can be reduced as much as possible, and a writing line with a uniform thickness is always provided. Can be provided.

[Brief description of drawings]

 FIG. 1 is a sectional view showing an embodiment of the present invention. 1 ... Ball chuck mechanism, 2 ... Holder 3 ... Holding member, 4 ... Slider, 5 ... Repellent member 6 ... Curved part, 7 ... Front end

Claims (1)

[Scope of utility model registration request] 1. A ball chuck mechanism, which allows the lead core to move forward but prevents the lead core from moving backward by a wedge action, is arranged in a holder, and a slider having a holding member is provided in front of the ball chuck mechanism. In an image drawing head which is biased forward by a repellant member and is slidably arranged, a curved surface portion is provided at least on the inner surface of the tip of the core insertion hole of the slider tip portion. head.