JPS5819967B2 - A-D conversion device for free parallel rulers, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an A-D conversion device used for converting the rotational motion of a rotating body into a digital signal in a universal parallel ruler, a coordinate analyzer, or the like.

As the encoder plate used to convert the rotational motion of a rotating body into a digital signal, a magnetic encoder plate and an optically readable slit plate are known.

Since magnetic encoder plates detect signals through contact with a detection head, the signal surface tends to wear out easily, and signal detection errors tend to occur after long-term use.

Although optically readable slit plates do not have this defect,
High-precision slit plates are made of hard glass, etc.
Extremely expensive.

In addition, when configuring an A-D converter using a hard slit plate, if the rotation center axis of the vernier slit plate is not set exactly perpendicular to the plane of the hard slit plate, the surroundings of the hard slit plate When the vernier slit plate rotates along
This causes a pulse generation error in the light receiving element.

This also applies when the vernier slit plate is fixed and the hard slit plate is rotated.In this case, the rotation center axis of the hard slit plate is aligned with the plane of the vernier slit plate. If it is not set vertically accurately, the distance between the hard slit plate and the vernier slit plate at the slit reading section will change as the hard slit plate rotates.

The present invention aims to eliminate the above-mentioned defects.

The configuration of the present invention will be described in detail below with reference to embodiments shown in the accompanying drawings.

Reference numeral 1 indicates the head of a free parallel ruler, 2 indicates a fixed plate (non-rotating body), and the fixed plate 2 is a head support means (not shown).
It is supported so that it can move in any direction while maintaining a predetermined orientation within a plane parallel to the drawing board 3 surface.

Reference numeral 4 denotes a plate that fits into a hole formed in the fixing plate 2, and the plate 4 is fixed to the fixing plate 2.

Reference numeral 5 denotes a main shaft rotatably fitted into a hole formed in the board 4, and a ruler mounting plate 6 (rotating body) is fixed to the lower end of this main shaft.

7 is a bundle, plate members 8 and 9 are fixed to the lower end of the bundle with screws, and the main shaft 5 is rotatably fitted into holes made in the plate members 8 and 9. .

The member 9 is fixed to the main shaft 5 with a screw (not shown).

A pair of straight rulers are detachably fixed to the ruler mounting plate 6 so as to be perpendicular to each other.

10 is an IC board fixed to the straightedge mounting member 6;
A vernier slit plate 12 is attached to a plate member 11 integrally formed therein so as to be parallel to the slit plate 13.

The slit plate 13 is made of an elastic member and is fixed to the lower surface of the fixed plate 2 along its outer periphery.

The slit plate 13 and the vernier slit plate 12 are transparent plates on which lines are provided in the form of a scale at a constant pitch.

The plate member 11 includes a pair of light receiving elements 14 (one not shown) made of a phototransistor and a pair of light emitting elements 15 (one not shown) made of a light emitting diode LED.
is attached, and the slit plate 13 and vernier slit plate 12 are arranged between them.

Reference numeral 16 denotes a spring fixed to the plate member 11 and located near the optical detection means 18 consisting of the light emitting and light receiving elements. They are in pressure contact.

The spacer is fixed to the upper surface of the vernier slit plate 12.

The position regulating surface 17 of the spacer is the vernier slit plate 1
A predetermined interval is set in a direction perpendicular to the upper surface of 2.

The spring 16 and the position regulating surface 17 are connected to the slit plate 1
3 and the vernier slit plate 12 in the vicinity of the optical detection means 18.

In this embodiment, the slit plate 13 is provided on the non-rotating body 2 side, and the vernier slit plate 12 and the light emitting/receiving elements 15 and 14 are provided on the rotating body 6, but the configuration is not limited to this. , the opposite configuration may be used.

Next, the operation of this embodiment will be explained.

When the bundle 7 is grasped by hand and force is applied in an arbitrary direction parallel to the drawing board 3 surface, the head 1 moves in an arbitrary direction within a plane parallel to the drawing board 3 surface.

At this time, the fixed plate 2 moves while maintaining a predetermined orientation.

When the bundle 7 is manually rotated, the members 8 and 9, the main shaft 5, and the ruler mounting plate 6 rotate in conjunction with the bundle 7,
The straightedge rotates in a plane parallel to the three sides of the drawing board.

At this time, the light receiving element 14, the light projecting element 15, and the vernier slit plate 12 move along the slit plate 13.

As a result of this movement, when the scale lines of the slit plate 13 and the scale lines of the vernier slit plate 12 coincide in the vertical direction, the light from the light projecting element 15 passes from the transparent portion of the slit plate 12.13 toward the light receiving element 14.

When the scale lines of the slit plate 13 and the scale lines of the vernier slit plate 12 do not match in the vertical direction, the light from the light projecting element 15 is blocked by the scale lines of the slit plates 12 and 13.

This causes brightness and darkness of light in the light receiving element 14, and two types of pulses, ie, a SIN pulse and a COS pulse, whose phases are shifted by 90 degrees are outputted from each output terminal of the pair of light receiving elements 14.

When the vernier slit plate 12 moves along the slit plate 13, if the facing distance between the vernier slit plate 12 and the slit plate 13 changes in the vicinity of the light receiving element 13, the brightness of the light appearing on the light receiving element 14 will change. This causes variations in the level of the light receiving element 14, which makes it impossible for the light receiving element 14 to output an accurate detection signal.

However, in this embodiment, the slit plate 13 is located on the position regulating surface 1.
7, the facing distance between the vernier slit plate 12 and the slit plate 13 is always maintained constant in the vicinity of the light emitting and light receiving elements 15 and 14.

A drafting worker draws a drawing on a sheet of paper on the drawing board 3 by moving the head 1 in parallel along the drawing board 3 and rotating the straight edge as appropriate.

Since the present invention is configured as described above, the distance between the slit plate and the vernier slit plate can be maintained constant, the light receiving element can be operated accurately, and there is no need to use an expensive hard slit plate. There are effects.

[Brief explanation of the drawing]

The drawings show a preferred embodiment of the present invention, in which Fig. 1 is a vertical cross-sectional front view of a universal parallel ruler head, Fig. 2 is a side view of the same, Fig. 3 is an enlarged view of the main part, and Fig. 4 A shows a slit. It is a partially enlarged plan view of a board, and a top view of a 06-i vernier slit board. 1...Head, 2...Fixed plate (non-rotating body), 3...Drawing board, 4...Panel, 5...
...Main shaft, 6...Ruler mounting plate (rotating body),
7...Bundle, 10...IC board,
12... Vernier slit plate, 13... Curved slit plate, 15... Light projecting element, 16... Interval spring, 17... Position regulating surface.

Claims (1)

[Claims] 1 A slit plate 13 made of an elastic member is attached to either the non-rotating body 2 or the rotating body 6 side, and a vernier slit plate 12 is attached to the other side facing the slit plate 13, and the slit plate 13 and the vernier slit A pair of light emitting elements 15 and a pair of light receiving elements 14 are disposed facing each other on the vernier slit plate 12 mounting side, and are positioned in the vertical direction of the plate 12, and the light emitting elements 15 and the light receiving elements 14 are disposed facing each other on the vernier slit plate 12 mounting side. A position regulating surface 17 is provided near the light and light receiving element 15.14 at a predetermined distance from the plane of the vernier slit plate 12, and the slit plate 13 is in elastic contact with the position regulating surface 17. A user-D conversion device for a universal parallel ruler, etc., characterized by the following.