JPH0453994Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a drawing head for an automatic drawing machine.

(Prior art and its problems) Compared to previous drawing heads that push down the lead in the axial direction and feed it out each time the lead wears out as a result of writing, this method automatically adjusts the lead as it wears out. A drawing head that can be extended out has attracted attention in recent years because of its ease of operation.

As illustrated in FIG. 3, the printing head has a ball chuck mechanism 101 disposed in a holder 102 that allows the lead core to advance but prevents its retreat by a wedge action, and a holding member in front of the ball chuck mechanism 101. A slider 104 having a slider 103 is biased forward by an elastic member 105 such as a spring and is slidably disposed.
By writing with the front end surface 106 of 04 pressed perpendicularly to the paper surface, the slider 104 is moved backward as the lead wears down, and when the pressure is released, the slider 104 returns forward due to the elastic force of the elastic member 105. The holding member 103 of the slider 104 allows the lead core to be pulled out from the ball chuck mechanism 101 while remaining flush with the front end surface 106. This eliminates the need for a complicated lead feeding mechanism.
By simply pressing the front end surface 106 of the slider 104 against the paper surface and then releasing it, the consumed lead can be fed out for continuous writing.

However, the above structure has the following problems. In other words, it is difficult to accurately drill holes 107 in the slider 104 through which a thin lead core of 0.5 mm or less can pass through smoothly, so the looseness caused by poor machining can cause the lead core to break or break. In addition, the front end surface 106 of the slider 104, which slides in contact with the paper surface during writing, wears out over a long period of use and the state of contact with the paper surface changes, causing problems such as a decrease in handwriting accuracy. This means that you will not be able to write.

Incidentally, the problem with the latter mentioned above is that the slider 104
It may be possible to change the material of the slider 104 to one that is hard enough to withstand wear, but this would make machining the slider 104 more difficult and create new problems in addition to the former, so it may not be a good idea. do not have.

(Purpose of the invention) The present invention was devised in view of the above-mentioned problems, and is a drawing head for an automatic drafting machine that can form the lead core passage hole of the slider with high precision and has excellent wear resistance on the front end face of the slider. This is what we intend to provide.

(Summary of the invention) The present invention satisfies the above object by fitting into the slider a pipe made of hard metal into which a lead core can be inserted, flush with the front end surface of the slider.

(Example) Hereinafter, the present invention will be explained in detail based on an example.

In FIG. 1, reference numeral 1 is a holder attached to a movable part (not shown) of an automatic drafting machine, and inside the holder 1 is a chuck 2 which is divided into a plurality of parts at the front and can be opened and closed. 2. A ball 4 placed on a ball receiving seat 3 having a dish-shaped longitudinal section formed on the front outside; an actuating body 6 having an inclined guide surface 5 capable of slidingly guiding the ball 4; A ball chuck mechanism 8 comprising a resilient member 7 such as a spring that biases the ball chuck 6 rearward is disposed. This ball chuck mechanism allows the lead core inserted into the chuck 2 to move forward, and prevents its retreat by a wedge action.In other words, the lead lead can move forward without resistance, but the writing pressure is When applied to a lead core, it is able to strongly hold the lead core against writing pressure. Therefore, if it satisfies this effect,
Of course, ball chuck mechanisms other than the illustrated example may be employed. Reference numeral 9 denotes a slider having a holding member 10 that can hold the lead core with a slight force, and the slider 9 is located in front of the ball chuck mechanism 8 and has a spring, etc. It is biased forward by an elastic member 11 and is slidably disposed. Further, the slider 9 has an outer step 12 in contact with an inner step 14 of a front holder 13 attached to the front end of the holder 1, and the front end protrudes from the front end of the front holder 12. Note that the tensioning position of the resilient member 11 is not limited to the front end surface of the actuating body 6, but may be on the front holder 13 or the inner surface of the holder 1. Further, a pipe 16 having an inner diameter that substantially matches the outer diameter of the lead core used is inserted into the hole 15 at the front end of the slider 9 with its tip flush with the front end surface 17 of the slider 9, Furthermore, it is fixed to the slider 9 by means such as press-fitting or adhesion. The slider 9 mentioned above is made of a relatively soft metal such as brass or nickel silver that can be precisely processed by cutting, drilling, etc.
Further, the pipe 16 is made of a relatively hard metal such as stainless steel or carbon steel, which has good inner diameter dimensional accuracy and excellent wear resistance.

Next, the operation of the above-mentioned embodiment will be explained using FIG. 2.

When writing, the holder 1 is vertically lowered by lowering the movable part (not shown) of the automatic drawing machine, and the front end surface 17 of the slider 9 and the lead L inserted into the pipe 16 are applied to the paper surface P under a predetermined pressure. Bring it into contact with. In this state, the holder 1 is slid parallel to the paper surface P to perform desired writing. At this time, the lead L is strongly held by the ball chuck mechanism 8 and cannot be moved back, so the lead L wears out as you write, and the slider 9 moves the front end surface 17 to the paper surface P. After finishing a prescribed writing operation of retreating against the holder 1 while in contact with the holder 1, the holder 1 is raised and the front end surface 17 of the slider 9 and the lead L are separated from the paper plane P, and the slider 9 moves against the resilient member 11. When returning, the lead core L is held by the holding member 10 and pulled out from the ball chuck mechanism 8 while remaining flush with the front end surface 106. Through this series of operations, the lead lead that has been consumed can be fed out for continuous writing.

During writing, the front end surface 17 of the slider 9 slides in contact with the paper surface P;
A pipe 16 made of hard metal fitted flush with the
Since the front end of the slider 9 also comes into contact with the paper surface P, wear of the front end surface 17 of the slider 9 can be prevented as much as possible.

(Effects of the invention) As described above, according to the invention, instead of directly forming a lead core passage hole in the slider, a pipe with excellent inner diameter dimension accuracy is inserted and fixed, and the lead core is inserted into the pipe. This eliminates the difficulty in directly processing and forming pores on the slider, and also prevents looseness with the lead lead, thereby solving problems such as breakage of the lead lead and reduction in handwriting accuracy. In addition, abrasion of the front end surface of the slider made of relatively soft metal during writing can be prevented as much as possible by the front end of the pipe made of hard metal that is inserted flush with the front end surface of the slider, so that the contact between the slider and the paper surface is minimized. It is possible to maintain the handwriting at the initial setting position and perform good handwriting.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing an embodiment of the present invention;
The figure is an explanatory diagram of the operation of FIG. 1, and FIG. 3 is a longitudinal sectional view showing the conventional example. 1...Holder, 8...Ball chuck mechanism,
9...Slider, 10...Holding member, 11...
Resilient member, 16...pipe, 17...front end surface.

Claims (1)

[Scope of utility model registration request] A ball chuck mechanism that allows the lead core to advance but prevents its retreat by a wedge action is disposed in the holder, and a slider having a holding member in front of the ball chuck mechanism is attached to the front by an elastic member. In the printing head arranged so as to be freely slidable, a pipe made of a harder metal than the slider through which a lead core can be inserted is inserted and fixed into the slider in a state flush with the flat surface of the front end of the slider. A drawing head for an automatic drafting machine characterized by: