JPH0440958Y2 - - Google Patents

Description

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

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. Optical reading type slit plates do not have this defect, but high-precision slit plates use hard glass, etc., and when constructing an A-D converter using this hard slit plate, it is difficult to use hard slit plates. If the axis of rotation of the vernier slit plate is not set exactly perpendicular to the plane of the slit plate, when the vernier slit plate rotates around the hard slit plate, the hard slit plate and the vernier slit plate may The facing distance between the slit reading section and the slit reading section changes, and this causes an error in pulse generation of 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 rigid slit plate is rotated relative to the plane of the vernier slit plate. If the central axis 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 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 designates the head of a flexible parallel ruler, and reference numeral 2 designates a fixed plate (non-rotating body). The fixed plate 2 is supported so as to be movable in any direction within a plane parallel to the plane of the drawing board 3 while maintaining a predetermined orientation.

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. Reference numeral 7 designates a handle, plate members 8 and 9 are fixed to the lower ends of these handles with screws, and the main shaft 5 is rotatably fitted into holes made in the plate members 8 and 9. ing. .
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. Reference numeral 10 denotes an IC board fixed to the straight edge mounting member 6, and a vernier slit plate 12 is attached to a plate member 11 integrally formed with the IC board so as to be parallel to a hard slit plate 13. The hard slit plate 13 is made of a transparent hard plate made of glass, hard plastic, etc., and the inner diameter part of the slit plate 13 is made of an elastic material made of a commercially available bellows fixed to the lower surface of the fixed plate 2 along its outer periphery. It is fixed to member 20. The slit plate 13 and the vernier slit plate 12 are transparent plates with lines arranged at a constant pitch in the form of a scale. A pair of light receiving elements 14 made of a phototransistor and a pair of light emitting elements 15 made of a light emitting diode (LED) are attached to the plate member 11, and the slit plate 13 and the vernier slit plate 1 are mounted between them.
2 is placed. 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 set at a predetermined distance from the upper surface of the vernier slit plate 12 in the vertical direction. The spring 16 and the position regulating surface 17 are connected to the slit plate 13.
and a vernier slit plate 12, an optical detection means 1
8 constitutes constant spacing keeping means for keeping the facing spacing constant in the vicinity of 8.

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

Next, the operation of this embodiment will be explained.

When the handle 7 is grasped by hand and force is applied in any direction parallel to the plane of the drawing board 3, the head 1 moves in any direction within a plane parallel to the plane of the drawing board 3. At this time, the fixed plate 2 moves while maintaining a predetermined orientation. When the handle 7 is manually rotated, the members 8, 9, the main shaft 5, and the ruler mounting plate 6 rotate in conjunction with the handle 7, and the straightedge rotates on a flat plate parallel to the 3 sides of the drawing board. do. 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 emitting element 15 is transmitted to the slit plates 12, 13.
The light passes from the transparent portion 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. As a result, the light receiving element 14
The light becomes bright and dark, and two types of pulses with a phase shift of 90 degrees are generated from each output terminal of the pair of light receiving elements 14, that is, SIN.
Pulse and COS pulse are output. 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 light appearing on the light receiving element 14 will change. Variations occur in the brightness level, and as a result, the light receiving element 14 cannot output an accurate detection signal. However, in this embodiment, since the slit plate 13 is in elastic contact with the position regulating surface 17, the facing distance between the vernier slit plate 12 and the slit plate 13 is always constant in the vicinity of the light emitting and light receiving elements 15 and 14. It will be held at 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.

As another example of the elastic member, a flexible elastic plate 20a as shown in FIG. 6 may be used. Further, as shown in FIG. 7, the hard slit plate 13 is attached to the fixing plate 2 by screws 25 via elastic members 20b, 20c made of sponge, foamed material, etc. and washers 24.
It may also be movably attached. Further, as another embodiment, as shown in FIG. 8, a hard slit plate 1
The screws 27 fixed to the fixing plate 2 are slidably inserted into the holes formed at multiple locations on the inner diameter of the washer 2.
Elastic members 29 and 30 made of springs may be elastically disposed between 8 and the plate 13 and between the plate 13 and the bottom surface of the fixed plate 2.

Since the present invention is configured as described above, the distance between the hard slit plate and the vernier slit plate can be maintained constant, the light receiving element can be operated accurately, and a highly accurate slit pattern can be formed. There are advantages such as being able to use a hard slit plate that is easy to install without requiring precision in its installation.

[Brief explanation of drawings]

Fig. 1 is a plan view, Fig. 2 is a sectional view, Fig. 3 is a sectional view, Fig. 4 is a sectional view, Fig. 5 is a plan view, Fig. 6 is a front view of another example, and Fig. 7 is the same. , a cross-sectional view, and FIG. 8 is a cross-sectional view of the same. 2...Fixed plate (non-rotating body), 3...Drawing board, 6...
... Ruler mounting plate (rotating body), 12 ... Vernier slit plate, 13 ... Hard slit plate, 15 ... Light emitting element, 17 ... Position regulating surface.

Claims (1)

[Scope of utility model registration request] A hard slit plate 13 is attached to either the non-rotating body 2 or the rotating body 6 via an elastic member 20 so as to be freely displaceable in a direction substantially parallel to the rotation center axis of the rotating body 6, and the rigid slit plate 13 is attached to the other side. Vernier slit plate 1
2 is attached facing the slit plate 13, and the hard slit plate 13 and the vernier slit plate 12
A pair of light emitting elements 15 and a pair of light receiving elements 14 are arranged opposite to each other on the vernier slit plate 12 mounting side, and A position regulating surface 17 is provided near the light and light receiving elements 15 and 14 at a predetermined distance from the plane of the vernier slit plate 12, and the rigid slit plate 13
An A-D conversion device for a universal parallel ruler, characterized in that a flexible parallel ruler is in elastic contact with the position regulating surface 17.