JPS5912429B2 - surface plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface plate that provides a standard plane for inspection, marking, etc., and the present invention aims to obtain a surface plate that has sufficient rigidity (and does not easily cause thermal distortion). It was invented for that purpose.

In the conventional surface plate of this type, as illustrated in FIG. 1, stiffness was provided by forming reinforcing lips 2, 2 in the shape of rough base grains on the back surface of a substrate 1 whose front surface was a reference plane.

However, it is difficult for air to pass through the back surface of the surface plate, and the reinforcing rib 2
, 2, air stays in the square 3°3 formed by 3°3, so the air circulation on the back side of the board is inferior to that on the front side of the board, so if the temperature of the group on the surface plate changes, the ambient temperature on the front and back sides of the board will change. There is a difference in the rate of change of the reference plane, and this causes a difference in thermal expansion between the front and back parts, which causes the reference plane to become distorted.

The present invention eliminates these disadvantages.

The present invention will be described below with reference to the embodiments shown in FIGS. 2 to 5.

In the surface plate of this embodiment, a support member 5 having a chevron-shaped wave cross section is placed on a square base plate 4, and a support member 6 having the same shape as this is placed on the support member 5 so that the ridge lines of both support members are perpendicular to each other. A square substrate 7 is placed on the support material 6, and the base plate 4, the support material 5゜6, and the substrate 7 are manufactured in a shape that is integrally joined. It is finished into a flat surface and used as a reference plane.

Reference numeral 8 denotes reinforcing stays formed at the tops of both ends of the supporting members 5 and 6, respectively.

Casting is suitable for manufacturing this surface plate.

The surface plate configured as described above has a configuration in which: (1) the base plate 7 and the base plate 4 are connected via a support part made of two chevron-shaped wave-shaped support members 5 and 6 that are connected orthogonally to each other; This is because the rigidity is large, the directionality of deformation due to only one chevron-shaped supporting material is canceled out, and the intersection points 12 of the tops of both base materials are evenly distributed with respect to the substrate 7 (Fig. 3). The shape of the substrate 7 has high stability.

(2) Since sufficient rigidity can be maintained by the support portions formed by the support members 5 and 6, the wall thickness of the substrate 7 and other parts can be made thinner, and the surface plate can be made lighter.

(3) A plurality of through passages 9 are formed between the substrate 7 and the support member 6, and the passages 9 are formed between the support member 5 and the base plate 4.
A plurality of passages 11 are formed in the direction perpendicular to the supporting member 5.
, 6 are orthogonal and mutually communicating passages 10at10.
Since b is formed, air circulation also improves on the back side of the substrate 7.

Therefore, if a suitable duct is connected to a part or all of the passages 9, 10a, 10b, and 11 and air is circulated through the passage by a fan, the ambient temperature on the front and back sides of the board 70 can be made equal, and the surface of the board 70 can be It is possible to prevent thermal deformation of the reference plane, and even when precise flatness is required, the temperature of the air surrounding the surface plate can be easily adjusted.

(4) It is also possible to have a structure in which a partition plate (not shown) is inserted between the supporting members 5 and 60 and connected to both supporting members 5 and 6;
According to this structure, the passage 10a.

Since 10b is eliminated, there is no effect of equalizing the temperature of the passages 9 and 11 as described above, but the effect of reducing the ventilation resistance of the passages 9 and 110 and further increasing the rigidity of the surface plate is produced.

(5) The reference plane can always be kept in the correct plane.

etc. are highly effective.

In the above embodiment, the shape of the surface plate is square, but it goes without saying that it can be made into any other shape such as rectangular or circular.

Furthermore, the above embodiment is an example in which the triangular wave-shaped supporting members 5 and 6 are changed in direction to form an overlapping support part, and this structure is extremely effective in increasing rigidity and reducing wall thickness. However, it is also possible to form the support portion by passing a passageway having a shape other than a triangle.

[Brief explanation of the drawing]

Koshirae Figure 1 is a perspective view of a conventional surface plate seen from the back, Figures 2 to 5 show an embodiment of the surface plate of the present invention, Figure 2 is a perspective view, Figure 3 is a plan view, and Figure 4 is a perspective view of a conventional surface plate. The figure is a side view, and Figure 5 is A- of Figure 4.
It is an A sectional view. 4: Base plate, 5, 6: Support material, 7: Substrate, 9°10a, 1
0b, 11: Passage.

Claims (1)

[Claims] 1. A surface plate characterized in that a supporting portion is coupled to the back surface of a substrate 7 whose surface is finished as a reference plane, and a plurality of passages opening to the side surface are formed in the supporting portion.