JPH0453200B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for feeding out the lead of a writing instrument used in an automatic drawing machine or the like.

Conventional technology Automatic drawing machines draw lines, etc. on recording paper by relatively moving a writing instrument and recording paper, and this writing instrument can slide freely through a pipe equipped with a lead chuck in a case equipped with a lead guide. The core is drawn out by inserting it into the pipe and sliding the pipe.

In such a writing instrument, if the impact when the lead is fed out and reaches the paper surface is large, the lead may break, or the lead chuck and the lead may slide relative to each other, causing the lead chuck and lead to slide relative to each other. This may cause premature wear of the core chuck.

Conventionally, therefore, the lead is slowly fed out until it reaches the paper surface, or the lead is allowed to reach the paper surface slowly to prevent core breakage and wear of the lead chuck.

Problems to be Solved by the Invention As mentioned above, in order to slowly unwind the lead and to have it reach the paper surface slowly, it is necessary to provide a position sensor and a speed sensor, and to use a complicated control circuit.

Means and operation for solving the problem In a writing instrument in which a lead chuck holding a lead is lowered by a motor and the lead is fed out from a lead guide, a drive current is applied to the motor for a minute time by inputting a lowering command. The core chuck 30 is lowered and driven by intermittent rotation driving the motor by repeatedly driving and stopping the motor at predetermined time intervals longer than the current time.
This is a core feeding method in which the core is fed out by descending intermittently with repeated stops, thereby allowing the core to reach the recording paper slowly.

Example FIG. 4 is a schematic front view of a writing instrument for a drawing machine,
A base 1 that can be moved in any direction by a moving mechanism (not shown) is provided with a writing instrument 2, a lifting mechanism 3, and a stopper 4, and the writing instrument 2 is slidably inserted into a cylindrical case 5 through a pipe 6. A sleeve 7 is integrally attached to the upper part of the pipe 6 that protrudes from the case 5, and a core stock 8 is inserted and a cap 9 is detachably attached to the upper part of the core stock 8. The case 5 is held on the base 1 by a holder 10, a stopper 4 is located above the cap 9, and driving and driven rollers 11 and 11' are pressed against the sleeve 7 to form the lifting mechanism 3. There is.

The writing instrument 2 is designed as shown in FIG.

That is, a core guide 20 is attached to the tip of the case 5, and this core guide 20 has a large diameter hole 22, a small diameter hole 23, and a core insertion hole 24 formed continuously and concentrically. A holding cylinder 25 is tightly fitted and fixed in the diameter hole 22, and the inside of the holding cylinder 25 and the small diameter hole 23 are tightly fitted and fixed.
The lead holding bush 26 is inserted so as to be able to move up and down, and the lead holding bush 26 is formed with a slit 27 that is open at the top so that it can be slightly deformed in the radial direction, and the lead inlet 26a is expanded upward. The upper small diameter part 26b is biased by the coil spring 28 to the upper position where it fits into the opening 25a of the holding cylinder 25, and the core is shaped like a funnel so that it is easy to insert the core. It is arranged so that it can move against the coil spring 28 to the lower position where it comes into contact.

A pipe 6 slidably inserted into the upper part of the case 5
A chuck ring 29 is fitted and fixed to the lower part of the
The inner circumferential surface 29a has a tapered shape expanding downward, and a steel ball 31 fitted into the lower outer circumferential surface of the core chuck 30 is in contact with the inner circumferential surface 29a.

The core chuck 30 is formed with a slit 32 opening at the bottom so that it can expand and contract in the radial direction, and the upper part of the core chuck 30 is slidably inserted into the upper part of the pipe 6. A core insertion hole 33 formed in the bottom 8a of the core stock 8 is opened concentrically with the core chuck 30, and the chuck ring 29 and the bottom of the core stock 8 are fitted and fixed to each other. A coil spring 34 is provided across the end face, and the chuck ring 29 and the core chuck 30 are connected to the coil spring 3.
4, the steel balls 31 come into pressure contact with the inner circumferential surface 29a of the chuck ring 29, so that the core chuck 30 shrinks and deforms in the radial direction to firmly hold the core.

Next, the operation will be explained.

When the drive roller 11 is stopped and the cap 9 is pushed while holding the sleeve 7, the core stock 8 slides downward along the pipe 6, and the core chuck 30 moves downward against the coil spring 34. Since the steel ball 31 moves away from the inner peripheral surface 29a of the chuck ring 29 and expands in the radial direction, the pencil lead A in the lead stock 8 passes through the lead chuck 30 and falls to the lead inlet 26a of the lead holding pusher 26. do.

When the pushing force of the cap 9 is released in this state, the core chuck 30 is moved upward by the coil spring 34, the steel ball 31 comes into pressure contact with the inner peripheral surface 29a of the chuck ring 29, and the core chuck 30 holds the core A. .

When the drive roller 11 is rotated in the normal direction and the pipe 6 is slid downward through the sleeve 7, the core chuck 30 moves downward together with the core stock 8, so that the core A is also moved downward, and the core A is moved downward from the core holding bush 26. , and protrudes downward from the core insertion hole 24 of the core guide 20, so that by rotating the drive roller 11 in the normal direction, the cores A are sequentially fed out, and when the lower end surface of the pipe 6 comes into contact with the upper surface of the core guide 20. The pipe 6 stops descending to the lowest position, and the feeding of the core stops.

FIG. 2 is a schematic diagram of the core feeding device, in which the drive roller 11 is rotationally driven by a motor 40, and a control circuit 41 supplies current to the motor 40.

The control circuit 41 is configured as shown in FIG. 1, and connects the + side of the power supply 42 to the - side input terminal 40 ₁ and the other side input terminal 40 ₂ of the motor 40 via the first and second switches 43 and 44, respectively. The - side is connected to the - side input terminal 40 ₁ and the other side input terminal 40 ₂ via the third and fourth switches 45 and 46, respectively.
The fourth switches 43 and 46 are the first AND gates 47
It turns on with the output of , and the second and third switches 44 and 45
is turned on by the output of the second AND gate 48, and one of the first AND gates 47 receives a lowering command _R1 from the CPU 49, and one of the second AND gates 48 receives a rising command R1 from the CPU 49. ₂ is input, and at the same time, a signal is input from the amplifier 50 to the other of the first and second AND gates 47 and 48.

The CPU 49 has a current command circuit 51, and this current command circuit 51 outputs a digital signal to output a set current at a predetermined time interval for a minute time as a current command signal to the D/A converter 52, and the D/A converter 52 outputs a digital signal as a current command signal.
The A converter 52 outputs an analog signal to the amplifier 50, and this analog signal is compared with the current _I0 detected by the current detector 53 in the comparator 54, and the motor 40 is output based on the constantly input analog signal. The current is supplied to the

The descending command _R1 and the current command are output in synchronization with the drive signal of the automatic drafting machine, and when the descending end detection signal of the sleeve 7, for example, the ON signal of the switch 55 provided in the case 5, is input to the CPU 49, the descending command is issued.
R ₁ is prohibited and the ascending command R ₂ continues to be output for a predetermined time, that is, until the sleeve 7 reaches its ascending limit, and after that time, the ascending command R ₂ is inhibited and the descending command is output.

Because of this, when the descending command _R1 and the current command are output, the first AND gate 47 outputs only a minute time at each time interval when the current command is output,
The first and fourth switches 43 and 46 are turned on for that minute time, and the current flows to the negative input terminal 40 of the motor 40.
₁ to the other side input terminal 40 ₂ for a predetermined period of time, e.g. 1.5 ms, as shown in FIG.
The motor 40 rotates at a predetermined time interval at a speed shown in FIG. 3 for that minute time, and the sleeve 7 descends at a speed corresponding to the speed at each time interval, and the core A is fed out. .

Therefore, the core A reaches the recording paper B slowly.

Then, since the sleeve 7 further descends, holding pressure can be applied when drawing a line, etc. on the paper surface with the lead A, and when the sleeve 7 reaches its lowering limit and the switch 55 is turned on, the descending command R ₁ is inhibited and the ascending command R is activated. ₂ outputs,
The second AND gate 48 outputs a signal, the second and third switches 44 and 45 are turned on, and current flows from the other input terminal 40 ₂ of the motor 40 to the negative input terminal 40 ₁ , and the motor 40 Since the rotation is reversed, the sleeve 7 rises.

When the sleeve 7 reaches its upper limit, the ascending command _R2 is prohibited and the descending command _R1 is output. Note that the time for the sleeve 7 to reach its upper limit may be calculated based on the rising distance and speed of the sleeve 7, or may be set in advance.

Note that the current command may continue to be outputted after the aforementioned core A reaches the paper surface, and the current command may also be continued to be outputted when the sleeve 7 is raised.

Effects of the Invention Since the lead A is lowered and fed out intermittently by repeating lowering and stopping in response to the input of the lowering command, the maximum descending speed of the lead A is commensurate with the drive current supplied to the motor 40 for a minute period, regardless of the lowering stroke. Because of this, the recording paper reaches the recording paper slowly regardless of the downward stroke, and core breakage and abnormal wear of the core chuck 30 do not occur.

Further, since the time required for the core A to come into contact with the recording paper is only increased by the time during which the core chuck 30 is stopped, the core A can reach the recording paper in a short time.

Further, since it is sufficient to simply control the drive current supplied to the motor 40, the control device can be made simple and inexpensive without requiring any special sensors or complicated control circuits.

Furthermore, since the chuck 30 only moves down intermittently relative to the case 5 when feeding out the lead A, the lead chuck 30 slides against the case 5 by the amount of the lead feeding stroke, resulting in an extra sliding stroke. The sliding part between the core chuck 30 and the case 5 does not wear out abnormally, and the core A
Since the sliding stylus slides against the lead guide 20 by the lead feeding stroke, the sliding stylus does not become extra long, and even if the lead A is a pencil lead, the lead guide 2
There will be no abnormal wear on the sliding parts with 0.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, in which Fig. 1 is a schematic explanatory diagram of core feeding, Fig. 2 is a control circuit diagram, and Fig. 3 is a chart showing the relationship between the current supplied to the motor and the speed.
FIG. 4 is an overall schematic diagram of the writing instrument, FIG. 5 is a detailed sectional view, and FIG. 6 is an explanatory diagram of the lead feeding operation. 20 is the core guide, 30 is the core chuck, A is the core,
B is the recording paper, and 40 is the motor.

Claims (1)

[Claims] 1. A core guide 20 is attached to the tip of the case 5,
A lead chuck 30 that holds the lead A inside this case 5
In a writing instrument in which the lead chuck 30 is moved up and down by a motor 40 to feed out the lead A, a drive current is applied to the motor 40 for a minute time for a predetermined time longer than the minute time by inputting a descending command. This writing instrument is characterized in that the lead chuck 30 is lowered intermittently by repeatedly lowering and stopping the lead chuck 30 to feed out the lead A by repeatedly driving and stopping the motor 40 by supplying it at intervals. How to feed out the core.