SU44706A1 - Instrument for monitoring protective glasses for sextants - Google Patents

Description

In the practice of controlling the mass production of protective glass filters for sextants, up to the present, there is no simple device that allows them to be tested for wedging, because the existing way of rejecting them does not allow the production of these glasses according to strictly defined tolerances for wedging. In practice, it is not uncommon to meet the issued glasses with a wedge angle exceeding four times the established tolerances,

The proposed device is intended to measure a wedge of protective glass filters and allows easy selection of glasses only with established tolerances. This instrument also makes it possible to measure with great accuracy the angle of the entire wedge of transparent material.

In the attached drawing of FIG. 1 shows schematically the device of the device and FIG. 2-field of vision of the oculist with displaced images of the slit.

The device consists of two identical collimators 5 with lenses and a double telescope. In the focal plane of the collimator lenses, a vertical slit 2 is placed, illuminated by a strong light source 1, for example an arc lamp. For example, thin Schtrich can serve as a gap

on the silver-plated surface of the glass plate.

The lower collimator has in front of the slit a plane-parallel plate 5 rotating around a vertical axis. This plate is rotated with a screw 4, the drum L of which is rotated by an observer who is not moving. The divisions of the drum are graded B seconds or fractions of seconds of the wedge angle. The telescope has lenses 8. The tubes of the lenses 8 are separated from each other. Helmholtz prisms 9 are placed in front of the oculum, which, in the section of the visual field, bring the images of the gaps of both collimators into contact.

At the zero position of the plane parallel plate in the ocular 10, both slits are located on the same straight line. By rotating the plane-parallel plate 3, one can notice the displacement of the lower image relative to the upper one. The same displacement of the upper slit can be caused by placing a glass wedge behind the upper collimator, the main section of which is horizontal (Fig. 2).

If the test glass is cut, for convenience of observation it is necessary to place a flat-parallel filter 6 of the same color in front of the lower lens.

The method of using the device is as follows. The plane-parallel plate is zeroed on the drum. Vision into the ocular, check correct alignment of both slits. Putting the drum in the position of the limit tolerance, note that the gap will shift. A filter (5 and test glass 7) is then placed behind the collimator. It is necessary to provide for the sample to be rotated in a plane perpendicular to the optical axis of the pipe so that it causes a deviation in the same direction as the plate is parallel to it.

If the deviation of the slit image from the sample does not exceed the deviation from plate 3, then the glass is considered suitable. - By combining both images of the slit, a click angle can be counted along the drum.

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A device for controlling protective glasses for sextants for cliose, characterized by the use of 5 two collimators 5 placed one above the other and provided with narrow slits 2, in front of one of which there is a rotating flat-pair glass plate 3 with a reading of the angle of rotation along the drum //, and a double telescope located in front of the collimators 5 with a common occulator W and the Helmholtz prisms which bring together the images of the slits, in front of the lenses of which telescope are placed in front of one test case e glass and in front of another light filter 6.