JPS5913107Y2 - Pencil drawing device for automatic drafting machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pencil drawing device for drawing predetermined figures, graphs, etc. on drawing paper using a pencil lead in an automatic drawing machine.

Conventional pencil drawing devices have used spring pressure, compressed air pressure, or a motor to apply the pen pressure necessary for drawing to the pencil lead.

Mechanisms that use spring force have the disadvantage that the pressure of the pen changes when the pencil lead is first set and when the lead wears down due to drawing due to a decrease in spring force.

In the method of using compressed air, a core rod that applies pressure to the pencil lead is connected to the piston rod of an air cylinder to apply pressure, but controlling low air pressure lacks stability.
Furthermore, because the responsiveness is not good, it takes time to draw a short series of dots that requires raising and lowering the pencil lead many times.

Recently, motors have been developed as a method to increase the so-called responsiveness of raising and lowering the lead of a pencil to maintain a constant pen pressure while shortening the drawing time, and to easily change the pen pressure when changing the thickness of the pencil lead. However, the conventional motor method used a rack and pinion to convert the rotational motion of the motor into linear motion, and this rack was connected to the core pusher to apply pressure to the lead of the pencil. .

This conventional method has the disadvantage that it is complicated, with many mechanisms and parts interposed between the motor and the lead of the pencil, and that the loss of rotational force generated in the mechanical parts is large.

In addition, due to the complexity of the mechanism from the motor to the tailstock, it is difficult to hold the thin tailstock just before it enters the core holder because it becomes even larger. When inserting the push rod into the lead holder, the tip of the push rod often did not fit properly into the hole in the lead holder, and the tip of the push rod often bent when the pencil lead was not worn out yet.

In addition, in conventional pencil drawing devices, at the beginning of drawing, the lead holder is brought close to the drawing paper and then pressure is applied to the pencil lead, and conversely, at the end of drawing, the pressure is released and then the lead holder is moved to the drawing paper. Although the core holder was moved away from the paper, it was equipped with a dedicated up-and-down mechanism that used a solenoid, motor, etc. as the driving force to raise and lower the core holder.

Therefore, as mentioned above, the operating procedure when drawing a line diagram is
The lead holder containing the pencil lead is lowered to near the surface of the drawing paper using the dedicated vertical mechanism, and then the pen pressure motor is operated to activate the lead rod that pushes the pencil lead and applies pen pressure. Based on the command, the cursor holding the drawing device is moved to draw, and when one line has been drawn, the tail rod is first pulled up by the motor, and then the lead holder is moved to the drawing paper using the dedicated up and down mechanism. Move away from the surface.

As described above, two control operations are always required at the beginning and end of drawing, and the time required for these operations results in loss of drawing time.

As mentioned above, if there are many parts between the pen pressure motor and the pencil lead, there will be a lot of loss in the intermediate transmission mechanism, but this means that the torque of the motor is converted and the pen pressure applied to the pencil lead becomes unstable. This became a factor, appearing in the shading of the pencil in line drawings drawn on drafting paper, resulting in poor drawing quality.

The pencil drawing device for automatic drafting machines of the present invention has improved the above-mentioned problems, and it minimizes the loss caused by the transmission mechanism until the torque of the motor is applied to the pencil lead as writing pressure. While making it possible to adjust the writing pressure when changing the thickness of the pencil lead, as was done with the device, we also simplified the mechanism for raising and lowering the lead holder containing the pencil lead to save time. This reduces loss and improves responsiveness.

Hereinafter, one embodiment of the present invention will be explained in detail with reference to the drawings.

Figures 1 and 2 are partial vertical cross-sectional views of the pencil drawing device for automatic drafting machines according to the present invention, with Figure 1 showing the state when not drawing, and Figure 2 showing the state during drawing. and
Further, FIG. 3 is an enlarged view of the A-a cross section in FIG.

A lead holder 2, which is attached to a cassette case 1 so as to be slidable up and down, is attached to a cursor (not shown) that moves back and forth and left and right on a drawing paper 17 according to instructions from a control device, and a lead holder 2 has a pencil lead 3 in the center. A holder head 7 and a tip fitting 8 are screwed together on the top and bottom of a pipe 4 which has a built-in friction ring 5 and a rubber ring 6 made of an elastic body, respectively, and when not drawing, a spring 9 The stopper 10 overcomes the dead weight of the lead holder 2 containing the pencil lead 3.
has been pushed up to the upper limit regulated by.

The rubber ring 6 attached to the pipe 4 by the tip fitting 8 supports the pencil lead 3 with a frictional force that is sufficient to prevent the pencil lead 3 passing through its center from falling under its own weight.

On the other hand, a case 11, which is a motor part of the cursor, is attached to the upper part of the force sensor 1 to the case 1, and a motor 12 for applying writing pressure to the pencil lead 3 is installed in the case 11. A roller 14 is provided at the shaft end 12' of the motor 12 with a groove that also serves as a guide for the tailing rod 13.
A tailstock rod 13 is interposed between the roller 14 and a corresponding driven roller 15, and the rotational movement of the motor 12 is controlled by the frictional force between these rollers and the tailstock rod 13. This is converted into a linear motion of the rod 13.

The case 11 is attached to the cursor so that the core pusher 13 is positioned directly above the lead 3 of the pencil, and the case 11 is designed to guide the core pusher 13 to a position as close to the lead holder 2 as possible. A pair of guide rollers 16 are installed.

When drawing, when the motor 12 is rotated, the rollers 14 and 1
The tailstock 13 held between the holders 5 and 5 descends, is guided by a guide roller 16, and passes through a hole in the center of the holder head 7 to push the friction ring 5.

The friction ring 5 is an elastic body, and the diameter of the hole in the center is the same as the tail rod 1.
3, and the frictional force between the two required for the core push rod 13 to slide through this hole is slightly larger than the push-up force of the spring 9. The core holder 2 is pushed by the core push rod 13, overcomes the pushing force of the spring 9, and is pushed down until it hits the cassette case 1.

As the motor 12 continues to rotate further, the core push rod 13 deforms the friction ring 5, passes through it, and descends, pushing the pencil lead 3 and when the tip of the pencil lead 3 reaches the drawing paper 17, it is pushed into the pencil lead 3. Apply pressure.

The pen pressure at this time is adjusted by controlling the voltage applied to the motor 12.

Here, a DC type or AC type torque motor is used as the motor 12, but as described above, the technology for adjusting the writing pressure of the lead of a pencil has already been established in the prior art, so it will not be described in detail.

When drawing is finished and the motor 12 is reversed and the tailstock 13 is pulled up, the lead holder 2 also moves between the friction ring 5 and the tailstock 13.
It is pulled up by the frictional force with the spring 9 and stopped at a position regulated by the stopper 10, supported by the spring 9.

As explained in detail above, by making the friction force between the lead pusher 13 and the friction ring 5 slightly stronger than the push-up force of the spring 9, the lead 3 of the pencil can be increased without increasing the torque loss of the motor 12. The housed core holder 2 can be moved up and down, and the core holder 13 and rollers 14 and 1
Since it has a simple structure that applies writing pressure to the pencil lead 3 by frictional force with the lead holder 2, it is also possible to install the guide roller 16 very close to the lead holder 2, and the writing pressure can be adjusted by applying voltage to the motor 12. Since this can be done by controlling the , it is possible to perform stable drawing with good responsiveness.

[Brief Description of the Drawings] Figs. 1 and 2 are partial longitudinal sectional views of an embodiment of the pencil drawing device for an automatic drawing machine according to the present invention, and Fig. 1 shows the state when not drawing; FIG. 2 shows the state during drawing, and FIG. 3 is an enlarged cross-sectional view of FIG. 1...Cassette case, 2...Lead holder, 3...Pencil lead, 4...Pipe,
5...Friction ring, 6...Rubber ring, 7...Holder head, 8...Tip fitting, 9...Spring, 10・・・・・・Sl～Brim, 11・・・Case, 12・・・Motor,
13...Coiling rod, 14...Roller,
15...Followed roller, 16...Guide roller, 17...Drawing paper.

Claims (1)

[Scope of utility model registration request] In a pencil drawing device of an automatic drafting machine, a lead presser of a pencil is sandwiched between a roller attached to the output shaft of a motor and a corresponding driven roller; The rotational motion of the motor is converted into the linear motion of the tailstock by frictional force, and the pencil lead in the lead holder is pushed by the tailstock, and the voltage applied to the motor is controlled to enable drawing. The lead holder is moved up and down by adjusting the necessary writing pressure of the pencil and moving the lead pusher up and down using the frictional force between the friction ring attached to the lead holder and the lead pusher. Features: Pencil drawing device for automatic drafting machines.