JPH05169896A - Lead clog detection device in automatic drafting machine - Google Patents

Abstract

PURPOSE:To prevent a fatal lead clog from occurring by a method wherein a lead remaining in a pen (a push button-type pencil) loaded on a pen head from a pen stocker is discharged, and with the judgement that the remaining lead has not been normally discharged, the approriate pen is returned to the pen stocker. CONSTITUTION:A plotting pen 4, which is a push button-type pencil, is loaded on a pen head 3 provided movably along a Y-axis rail of a plotter. The pen head 3 is provided with a push plate 20, a movable pen pressure arm 21 lifted or lowered by a motor 23, and an up/down arm 22. When a lead 36 held in the pen 4 is exhausted, the lead 36 can be always projected by a fixed length by lowering an inner barrel part 31 through the pen pressure arm 21. At the replacement of the pen 4, a remaining lead discharge processing is conducted. In this invention, whether a remaining lead has been normally discharged is judged by detecting a rotating amount of the motor 23, i.e., a lowering amount of the inner barrel part 31 (a new lead extrusion amount). When the judgement is negative, the pen 4 is returned to a pen stocker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core clogging detection device for an automatic drafting machine, which can quickly detect a slight core clogging when a pen is replaced and prevent a fatal core clogging.

[0002]

2. Description of the Related Art A pen head holding a knock type pencil is moved along a screen to perform drawing with the pencil lowered, and a horizontal movement or lead in a non-drawing state with the pencil raised. An automatic drafting machine (plotter) for drawing out is extremely useful because it can express the drawing data created by CAD at an arbitrary magnification.

At the time of drawing, the pen head is moved along the drawing screen while the pencil lead protruding from the tip of the pencil is brought into contact with the drawing screen with a predetermined writing pressure, so that the pencil lead is consumed in proportion to the drawing time. When the core is exhausted during drawing, the core is gradually extended to extend the core, but when the pen is down to a position where the core cannot be extended, once the pen is up, the centering knock is performed, and then the pen is down again to continue drawing. To do. Generally, one pencil lead is used by being fed out part by part by a plurality of centering knocks.

If one pencil lead is used to the end, only one lead is built in unless it is a multi-core pencil.
Need to change pen. This pen replacement is an operation in which the pen head is moved to a pen stocker located at a position off the drawing screen, and the pen is replaced with another pen which is automatically cored and is on standby to return to the drawing position. The pen head that takes in a new pen through such pen replacement first performs the residual core discharging operation. This is an operation of pushing out the short residual core remaining in the taken-in pen with the newly supplied new core.

[0005]

In the above-mentioned residual core discharging operation, if the scraps of the core are attached to the inside of the core through hole or the residual core is inclined in the pen, the residual of the new core is left well. The lead cannot be discharged. At this time, if the new core is further pushed in, a part of the residual core or the new core is broken and accumulated in the pen. If the new core is further pushed in even in such a slight core clogging state, in some cases, the core is tightly clogged in the core through hole, which causes a fatal core clogging state that cannot be easily repaired.

An object of the present invention is to improve such a point and prevent the fatal core clogging from occurring by promptly detecting the above-mentioned slight core clogging and replacing the pen again. ..

[0007]

In order to achieve the above object, according to the present invention, a pen head holding a pencil is moved along a screen to perform drawing with the pencil lowered, and the pencil is drawn. In the core clogging detection device of the automatic drafting machine that moves the pen to the stocker outside the area and replaces the pen, the means for discharging the residual core of the pen taken in from the pen stocker to the pen head, and the normal core removal operation in the residual core discharging operation. And a means for returning the pen held by the pen head to the pen stocker when it is determined by this means that the lead is not normally discharged. Is characterized by.

[0008]

In the pen replacement, when the pen is taken in from the pen stocker and the residual core is discharged first, if the residual core can be discharged without any problem, the load on the drive source for discharging the residual core does not become so large. However, at this time, if the lead is clogged inside the pen and the residual lead cannot be discharged properly, the load on the drive source increases. For example, when the drive source is a motor, load fluctuations appear as a drive current value (when current value control is not performed) or a rotation amount change (when constant current drive). Therefore, the controller monitors this load fluctuation, and if it detects a load fluctuation that does not occur during normal residual core discharge, it determines that the core is clogged, stops the residual core discharge operation, and returns the pen to the pen stocker. By doing so, it is possible to avoid fatal clogging of the core caused by continuing the residual core discharging operation forever.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing the entire paper moving type plotter according to an embodiment of the present invention. In this figure, a Y-axis rail 2 is erected on a support base 1 with a carry, and a pen head 3 that moves along the Y-axis rail 2 is mounted on the Y-axis rail 2. A pen 4 for drawing and a scope 5 for digitizing are attached to the pen head 3, and a drawing roller (not shown) is arranged immediately below the pen 4. The recording paper 6 is conveyed in the X direction between the drawing roller and the pen head 3, and is entirely covered by a protective cover 7 that can be opened and closed.

A pen stocker accommodating portion 8 is formed at one end of the Y-axis rail 2, and a pen stocker holding a plurality of pens of different pen types and a pencil lead having a different core diameter are separated from each other. A wick accommodating portion that accommodates is arranged. Then, when the pen is replaced or when a new lead is requested, the lead selected from the lead storage portion is inserted into the pen having a corresponding lead diameter and is delivered to the pen head 3. A housing 9 for a motor that drives the pen head 3 and various rollers is formed at the other end of the Y-axis rail 2. Furthermore, at the top of this plotter,
An operation panel 10 is provided, on which a memory card 11 for registering various parameters, operation sets, etc. can be mounted.

FIG. 2 shows the details of the pen head 3 and the outline of the pen 4. The pen head 3 has a fixed knock plate 20, a movable writing pressure arm 21, and an up / down arm (hereinafter abbreviated as U / D arm) 22 on the outside, and
A motor 23 for raising and lowering the writing pressure arm 21, a linear encoder 24 for detecting the amount of elevation, and a U / D arm 2 are provided inside.
It has a moving coil 25 that moves up and down 2, a rack and pinion mechanism 26 that converts the rotation of the motor 23 into a linear motion, and the like.

The pen 4 is a knock type pencil and is basically composed of three coaxial members 30 to 32. Reference numeral 30 is a centermost knock portion, 31 is an intermediate middle body portion, and 32 is an outermost holder portion. The knock portion 30 has a knob 33, which is brought into abutment with the knock plate 20 fixed to the uppermost position of the pen head 3 when knocking. The middle body 31 is the writing pressure brim 3
4 and is fitted and held by the writing pressure arm 21 in the center of the pen head 3. The holder portion 32 has a holder collar 35, which is fitted and held by the U / D arm 22 located at the lowest position of the pen head 3. 36 is a pencil lead protruding from the tip of the holder.

The motor 23 raises and lowers the writing pressure arm 21 via a rack and pinion mechanism 26, whereby the middle body 3
Raise and lower 1. The moving coil 25 moves the holder 32 up and down via the U / D arm 22. Pen-up required for drawing with these two drive sources 23, 25,
Various operations such as pen down, writing pressure application, and centering are performed. This will be described below with reference to the detailed sectional view of the pen 4 shown in FIG.

The knock part 30 is entirely hollow, and a new core 36 is supplied from the upper open end 40. This knock part 30
The lower end of the is a slot-shaped chuck 41 so that the supplied core 36 can be firmly gripped. The middle body 31 is also entirely hollow, and has a hole 42 at the lower end through which the lead 36 passes, and a cavity 43 for opening the chuck is formed in front of it. The holder portion 32 is also entirely hollow, and has a core projecting hole 44 formed at the lower end thereof, and a braking rubber 45 capable of holding the core 36 by frictional force is provided inside thereof.

A first portion is provided between the knock portion 30 and the middle body portion 31.
A return spring 46 is interposed, and a second return spring 47 is interposed between the middle body portion 31 and the holder portion 32. Therefore, in the natural state, for example, with the middle body portion 31 as a reference,
The knock portion 30 is displaced upward, and the holder portion 32 is displaced downward. In this case, depending on the shape of the cavity 43 of the middle body portion 31 that accommodates the tip of the chuck 41, the knock portion 30
There is a limit to the upward displacement of. Further, the step portion 48 in which the holder portion 32 and the middle body portion 31 engage with each other allows the holder portion 32 to be
There is a limit to the downward displacement of.

As a fourth member, a core follow-up tube 50 having a hole 49 for penetrating the core is housed inside the holder portion 32. The core follow-up tube 50 has a hole 42 in the middle body portion 31 and a hole 44 in the holder portion 32.
It is an intermediate core guide with. This lead tracking tube 50
Is movable in the axial direction between the middle body part 31 and the holder part 32, but is always biased by the third return spring 51 so as to be displaced upward.

With the above pencil structure in mind, the operation of the head shown in FIG. 2 will be described again. First, the head 3 is the pen 4
When the motor 23 is rotated and the middle body portion 31 is raised while holding, the knock portion 30 also rises at the same time due to the elasticity of the first return spring 46, and the knob 33 eventually collides with the lower surface of the knock plate 20. To meet. This state can be detected by the torque fluctuation of the motor 23. When the middle body portion 31 is raised, the holder portion 32 is also raised at the same time.

When the knob 33 abuts the lower surface of the knock plate 20 and then the motor 23 is further rotated to raise the middle body portion 31, the void 43 of the middle body portion 31 reaches the tip position of the chuck 41, The chuck 41 is released. When the chuck 41 is opened, the core 36 drops downward through the chuck 41, passes through the hole 42 of the middle body portion 31 and the hole 49 of the core follow-up tube 50, and reaches the braking rubber 45. In order to ensure this core drop, it is better that the holes 42, 49 and the braking rubber 45 are closer to each other. Therefore, the holder portion 32 is sufficiently raised and the lead follow-up tube 50 is pushed up to approach the tip of the middle body portion 31.

When the lead 36 drops from the chuck 41, the holder 32 is lowered with the chuck 41 left open. As a result, the lead 36, the tip of which is abutted against the braking rubber 45, is further pulled out from the inside of the chuck. The amount of lowering of the holder portion 32 determines the centering length for each centering. When this centering is completed, the middle body part 31
Is slightly lowered to close the chuck 41 to firmly hold a part of the core 36.

When the core 41 is held by the chuck 41, when the holder portion 32 is fixed and the middle body portion 31 is lowered, the knock portion 30 is also integrally lowered. It penetrates 45 and projects below. Now you are ready to draw. After that, when the protruding core 36 is consumed as a result of drawing, the core 36 is always protruded by a certain length by lowering the middle body portion 31 by that amount. When the inner trunk portion 31 eventually descends to the lowermost end, the core 36 cannot be further projected. Therefore, the above-described knocking operation involving opening the chuck is performed. Generally, it takes several knocking operations to use up one core 36.

Drawing is performed with the pen 4 down,
Centering is performed with the pen 4 up. Also, the pen replacement and line segment movement during printing are performed at an up position lower than the centering. The pen 4 having this structure applies a desired writing pressure by the force of pressing the middle body portion 31. Therefore, the motor 23 is used not only for the lead-out control of the lead but also for the writing pressure control.

FIG. 4 shows a pen stocker 70 housed in the pen stocker housing portion 8 of FIG. 1 and a lead tank (lead housing portion).
It is a schematic block diagram of 80. The pen stocker 70 is of a rotary type, has a rotary shaft 71 in the center thereof, and has brim portions 72 and 73 having concave portions capable of holding a plurality of pens 4 in the circumferential direction. This recess is numbered circumferentially,
A pen of the determined pen type is held at the corresponding pen number position. The lead tank 80 is located above the pen stocker, and a plurality of tanks 81, 82. ... has multiple pencil cores with different core diameters. Each tank 81, 82,
There is a lead drop portion such as a chuck mechanism at the bottom of the ..., and a lead 36 having a required lead diameter is provided from the knock portion 30 of the pen 4.
It is supplied to (free fall). Selection of core diameter is core tank 80
By rotating.

According to the present invention, when the pen is replaced, the residual lead discharging operation is stopped by promptly detecting the core clogging during the residual lead discharging operation. Taking the pencil in FIG. 3 as an example, 36 is a new core that is automatically cored, and the residual core is separated from the chuck 41 and is retained only by the braking rubber 45 (in some cases, holes 42 and 49). In this state, if the residual core cannot be discharged properly by pushing the residual core with a new core, the space between the holder portion 32 and the core following tube 50, or the space between the core following tube 50 and the middle barrel portion 31. Core breakage or slight core clogging occurs in the space.

Even in such a state, when the new core is further pushed in, the broken core in the space becomes slanted or lie, and the holes 49 and 44 are closed, and the dead core cannot be easily repaired. Causes a jam condition. In the present invention, this clogging of the core is detected from the magnitude of the load on the residual core discharging drive source. Figure 2
In the pen head of, since the motor 23 is this drive source,
The magnitude of the load can be determined from the drive current value or the rotation amount. FIG. 4 is an explanatory diagram of this.

In FIG. 5, reference numeral 60 denotes a controller (CPU) that performs various controls, and here, a configuration relating to control of the motor 23 is shown. This CPU60 is PWM
(Pulse width modulation) circuit 61 outputs a control output to the PW
The M circuit 61 intermittently controls the time of the current flowing through the motor 23 (controls the average current value). The current value actually flowing through the motor 23 is detected by reading the value digitally converted by the A / D converter 62 with the CPU 60. On the other hand, the mechanical rotation of the motor 23 is detected by the linear encoder 24.

In this embodiment, a constant current is applied to the motor 23 when the residual core is discharged, and the encoder 24 detects the amount of lowering of the middle barrel portion 31 (amount of pushing out a new core). That is, when the residual core discharge is normally completed, the output of the encoder 24 changes by a predetermined amount while the motor 23 is supplied with a constant current. However, if the residual core discharge is not correct, the output of the encoder 24 does not change so much. When the CPU 60 determines from this difference that the core is clogged, it immediately stops the residual core discharging operation. Then, an instruction is issued to replace the pen again. By doing so, even if the core is clogged during the remnant discharging operation at the time of pen replacement, it can be left in a minor state in which it can be repaired, so that it occurs by continuing the remnant discharging operation forever. Deadly core clogging can be avoided.

The present invention is not limited to the above embodiment. In other words, when the recording paper is fixed on a flat screen and the pen head is moved in the XY directions to apply to a flat bed type plotter, the pen stocker is a fixed type called a pen line outside the drawing area. There, a plurality of recesses in which a plurality of pens are fitted and housed are formed. Further, the portion for discharging the residual core may be formed in a different place from this pen stocker.

The pencil used is not limited to that of the embodiment. That is, a plurality of cores are housed in the knock portion in advance, and
There is a multi-core knock type pencil that uses one book at a time, and there is also a single core type extrusion pencil that has no chuck mechanism and puts one core in a simple cylinder and pushes it out with a pushing member.

[0029]

As described above, according to the present invention, in an automatic drafting machine using a knock type pencil, when a slight lead clogging is detected in the residual lead discharging operation at the time of pen replacement,
Since the residual core discharging operation is immediately stopped and the pen is replaced again, there is an advantage that fatal core clogging can be avoided.

[Brief description of drawings]

FIG. 1 is an external perspective view of a paper moving type plotter showing an embodiment of the present invention.

FIG. 2 is a detailed configuration diagram of a pen head portion of the plotter.

FIG. 3 is a cross-sectional view of a knock type pencil.

FIG. 4 is a configuration diagram of a pen stocker portion.

FIG. 5 is a configuration diagram of a main part of the present invention.

[Explanation of symbols]

3 ... Pen head, 4 ... Knock type pencil, 6 ... Recording paper, 8 ... Pen stocker housing, 10 ... Operation panel, 20
... knock plate, 21 ... writing pressure arm, 22 ... up / down arm, 23 ... motor, 24 ... linear encoder, 25
… Moving coil, 30… Knock part, 31… Middle trunk part,
32 ... Holder part, 33 ... Knob, 34 ... Writing pressure collar, 35 ...
Holder collar, 36 ... Lead, 41 ... Chuck, 45 ... Braking rubber, 50 ... Lead follower tube, 60 ... Controller, 61 ... PW
M circuit, 62 ... A / D converter, 70 ... Pen stocker, 8
0 ... wick tank.

Claims (1)

[Claims] 1. An automatic drafting system in which a pen head holding a pencil is moved along a screen to perform drawing with the pencil lowered, and the pencil is moved to a pen stocker outside the drawing area for pen replacement. In the core clogging detection device of the machine, means for discharging the residual lead of the pen taken into the pen head from the pen stocker, and means for determining whether the residual lead is normally discharged in the residual lead discharging operation, And a means for returning the pen held by the pen head to the pen stocker when it is determined that the residual core is not normally discharged by the means.