JPH0443354Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for digitally displaying the straight edge angle of a universal parallel ruler.

Conventionally, this type of device was
The one described in the No. 3 publication is publicly known. The electronic circuit of the above device includes an inversion circuit 2, as shown in FIG. The rotational movement of the ruler mounting plate 6 of the head 4 is converted by a pulse encoder 8 into a pulse signal having a directional component, and this pulse signal is supplied to an up-down counter 12 via a direction determining circuit 10. The direction discrimination circuit 2 outputs a pulse from an output terminal a when the slit plate 14 of the pulse encoder 8 rotates in the forward direction, and outputs a pulse from the output terminal b when the slit plate 14 rotates in the reverse direction. Whether the pulse of the pulse encoder 8 appears at the output terminal a or the output terminal b of the direction determining circuit 10 is determined by the direction component of the output pulse of the pulse encoder 8, that is, the lead or lag of the phase of the pulse. . Updown counter 1
2 adds a pulse when a pulse is input to its up-count input terminal U, and subtracts a pulse when a pulse is input to its down-count input terminal D. In the universal parallel ruler, the angle of the horizontal straight edge 16 must be expressed as an absolute value with zero degrees as a reference. Therefore, an inverting circuit 2 is provided between the direction determining circuit 10 and the counter 12 to invert the increase/decrease relationship of the counter 12 with respect to zero degrees. Horizontal straightedge 1 in Figure 1
Let state 6 be zero. Setting to zero is done by resetting the counter 12. When the handle 4a of the head 4 is grasped by hand, and the handle 4a is rotated in the direction of rotation of the hour hand in the counterclockwise direction in FIG. The pulse appears at the output a of the direction determining circuit 10. The pulse appearing at the output terminal a appears at the output terminal a' of the inverting circuit 2, and the pulse at this output terminal a' is inputted to the up-count input terminal U of the counter 12. counter 12
counts this pulse. The count value of the counter 12 at this time is digitally displayed on a display section 18 provided in the head 4. Suppose now that 30 degrees is displayed on the display.

Next, when the ruler mounting plate 6 is rotated 20 degrees in the direction of rotation of the hour hand in FIG. is inputted to the down-count input terminal D of the counter 12 via the output terminal b' of the inverting circuit 2, and the counter 12 subtracts the input pulse from the current value. When the rotation of the ruler mounting plate 6 stops, the display section 18 displays 30 degrees - 20 degrees = 10 degrees.

Next, a case will be described in which the ruler mounting plate 6 is further rotated by 20 degrees in the direction of rotation of the hour hand in FIG.

When the amount of rotation of the ruler mounting plate 6 reaches 10 degrees, the display section 18 displays zero. This zero is detected by the zero detection circuit 20, and the flip-flop of the inverting circuit 2 is inverted by this detection signal. Due to this inversion, the pulse appearing at the output terminal b of the direction determining circuit 10 appears at the output terminal a' of the inverting circuit 2, with zero as the boundary. As a result, the counter 12 subtracts pulses from the 10 degrees to zero degrees, and when the straight edge 16 exceeds zero degrees in the hour hand direction, it adds pulses. In the end, 10 degrees is displayed on the display. From this state, when the ruler mounting plate 6 is rotated 20 degrees in the counterclockwise rotation direction in FIG. The absolute value based on zero degrees, ie, 10 degrees, is displayed on the display section 18.

In the case of the above circuit configuration, digital encoder 8
Since the inverting circuit 2 is interposed between the counter 12 and the counter 12, this causes a decrease in response performance, that is, speed. However, there is currently a demand for a universal parallel ruler with a high-resolution digital display function. In a high-resolution digital display device, if the response performance is poor, there is a high possibility that the counter 12 will malfunction when the ruler mounting plate 6 rotates at high speed. In particular, when the ruler mounting plate 6 stops due to an impact caused by the index mechanism built into the head 4, the movement of the ruler mounting plate 6 due to vibration is extremely fast, and this movement causes the counter 12 to malfunction. You end up doing it. Also, counter 1
Since the zero of 2 is detected and the inverting circuit 2 is inverted by this, the timing of inversion is delayed at the zero position and the count of the counter 12 advances, which may cause malfunction of the counter 12. It's summery.

The present invention aims to provide a digital display device of a universal parallel ruler having a high-resolution, high-precision digital display function, which eliminates the above-mentioned defects by providing two counters without providing the above-mentioned inverting circuit. This is the purpose. The structure of the present invention will be described below with reference to embodiments shown in the accompanying drawings.

In FIG. 2, 22 is the main shaft of the head 4, and a handle 4a is fixed to the upper end of the main shaft. A substrate 24 is fixed to the main shaft 22, and a ruler mounting plate 6 is attached to the substrate 24. 26 is a protractor, which is fixed to the head support substrate 28. A gear 30 is fixed to the outer periphery of the protractor 26, and the gear 30 has a support shaft 3 of the slit plate 14.
A gear 34 fixed to 2 is in mesh with each other. The support shaft 32 is rotatably supported by a holder 36 fixed to the substrate 24. The holder 36 has a pair of light emitting elements 38 and a pair of light receiving elements 4.
0 and a vernier slit plate 42 are attached. The slit plate 14, the light emitting element 38, the light receiving element 40 and the vernier slit plate 42 constitute a known pulse encoder 8. When the handle 4a of the head 4 is rotated, the substrate 24 is rotated,
The holder 36 moves along the outer periphery of the protractor 26. As the substrate 24 rotates, the gear 34 moves along the gear 30 while rotating. The slit plate 14 rotates as the gear 34 rotates, and the pair of light receiving elements 40 output a pair of pulse signals having different phases depending on the direction of rotation of the slit plate 14. 10
is a direction discrimination circuit which outputs the output pulses of the pulse encoder 8 to either output terminal a or b. When the slit plate 14 rotates in the forward direction, the pulses of the encoder 8 appear at the output terminal a, and when the slit plate 14 rotates in the reverse direction,
Appears at output end b. 44 is a first up-down counter, and its up-count input terminal C
is connected to the output terminal a of the direction discrimination circuit 10, and the down count input terminal d is connected to the output terminal b of the direction discrimination circuit 10. 46 is a second up-down counter, whose up-count input terminal f is connected to the output terminal b of the direction discrimination circuit 10, and whose down-count input terminal e is connected to the output terminal a of the direction discrimination circuit 10. ing. The output terminals of the counters 44 and 46 are connected to a display drive circuit 52 via three-state buffer amplifiers 48 and 50. 18 is a display section, and the head 4
installed on. Reference numerals 54 and 56 indicate zero detection gate circuits that detect zero of the counters 44 and 46 and turn the gates on when the counters are in the zero state. and is connected to the counter display switching circuit 62. The input terminals of the circuits 54 and 56 are connected to the output terminals a and b of the direction determining circuit 10, respectively, as shown. The display switching circuit 62 receives pulse signals from the gates of the zero detection gate circuits 54 and 56, and switches the display switching circuit 62 to the amplifier 4.
It performs an operation of switching the impedance of 8 and 50 to either a high or low state. When the output terminal g of the switching circuit 62 is 1 and the output terminal h is zero, the amplifier 48 becomes a low impedance, the amplifier 50 becomes a high impedance, and the output terminal g of the switching circuit 60 is zero and the output terminal h is "1".
At this time, the amplifier 48 is set to high impedance and the amplifier 50 is set to low impedance.

Each of the circuits is integrated into the head 4 as an IC.

Next, the operation of this embodiment will be explained.

First, counters 44 and 46 are reset to zero. Next, when the handle 4a of the head 4 is rotated, a pulse signal having directionality is generated from the pulse encoder 8.
6 respectively. Now, the direction determination circuit 10
If a pulse appears at the output terminal a of the first counter 44, the first counter 44 adds the pulse from zero and
The counter 46 subtracts the pulse from zero.
That is, the relationship between increases and decreases in the counters 44 and 46 is opposite. In this state, amplifier 48 is in a low impedance state and amplifier 50 is set in a high impedance state. The count output of the counter 44 is supplied to the display drive circuit 52 via the amplifier 48, and the count value of the first counter 44 is digitally displayed on the display 18. Rotate the handle 4a in the opposite direction, that is, as shown in FIG.
When rotating in the direction of the hour hand, the output pulses of the encoder 8 appear at the output terminal b of the direction determining circuit 10. When the counters 44 and 46 reach zero while pulses are continuously appearing from the output terminal b, the zero detection gate circuits 54 and 56 detect zero,
The gate is made conductive.

Next, when one pulse is supplied from the output terminal b to the zero detection gate circuit 54, the pulse passes through the AND gate 58 and then passes through the counter display switching circuit 62.
is supplied to This causes the switching circuit 62 to operate, outputting zero at the output terminal g and outputting "1" at the output terminal h, thereby switching the amplifier 48 to a high impedance state and the amplifier 50 to a low impedance state. As a result, the count value of the second up-down counter 46 is displayed on the display section 18. In other words, the display unit 18 displays the numbers from zero to 0,99999...
It increases by 1, 2, 3 instead of .... When the output of the second counter 46 is displayed, the handle 4a of the head 4 is rotated in the counterclockwise rotation direction in FIG. 1, and when the counters 46 and 44 output zero, the counter display switching circuit 6 teeth,
It is operated by one pulse of the output terminal a supplied from the zero detection gate circuit 56 via the AND gate 60, and the output terminal g outputs "1" and the output terminal h outputs zero, putting the amplifier 48 in a low impedance state. and switches the amplifier 50 to a high impedance state. By the switching operation of the counter display switching circuit 62, the absolute angle of the horizontal straightedge 16 in the forward and reverse directions with respect to zero degrees is always digitally displayed on the display section 18.

In this embodiment, the display drive circuit 52 is provided on the output side of the amplifiers 48 and 50;
It may also be provided on the input side of 8 and 50.
Note that the configuration for automatically switching the counter display switching circuit 62 is not particularly limited to the illustrated circuit.

As mentioned above, this invention selects the display of one of the two counters based on zero, so the counter does not malfunction and has a flexible ruler angle digital display function with high resolution and precision. This has the effect that parallel rulers can be supplied.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the digital universal parallel ruler, Fig. 2 is a sectional view of the head, Fig. 3 is a circuit diagram of the conventional scheme, Fig. 4 is a block circuit diagram of the same, and Fig. 5 is a preferred embodiment of the present invention. FIG. 2 is a block circuit diagram showing an embodiment. 8... Pulse encoder, 10... Direction discrimination circuit, 14... Slit plate, 18... Display unit, 4
4, 46...Up-down counter, 62...
Counter display switching circuit.

Claims (1)

[Scope of utility model registration request] The rotational movement of the straight edge is converted into a pulse signal having directionality by a pulse encoder 8, the pulse signal is counted by an up-down counter, and the count value is digitally displayed on a display section 18. The apparatus includes a direction discrimination circuit 10 that detects the direction of the pulse signal of the pulse encoder 8 and outputs a pulse from one of two output terminals depending on the direction; The first output terminal has an up-count input terminal connected to one of the two output terminals, and a down-count input terminal connected to the other output terminal.
Of the two output terminals of the up-down counter 44 and the direction discrimination circuit 10, the down-count input terminal is connected to the output terminal to which the up-count input terminal of the first up-down counter 44 is connected, and Of the two output terminals of the discrimination circuit 10, the second up-down counter 46 has an up-count input terminal connected to the output terminal to which the down-count input terminal of the first up-down counter 44 is connected; The output of one of the second up-down counters 44 and 46 is selected based on zero, and the selected output is electrically connected to the display section 18. 1. A digital angle display device for a universal parallel ruler, characterized by comprising a counter display switching circuit 62.