US1760372A - Micrometer or the like - Google Patents

Description

May 27, 1930. E. G. PEHRSSON 1,760,372

MICROMETER OR THE LIKE Filed May 16, 1927 Patented May 27, 1930 UNITED STATES EEIK e. rEHE'ssoN, or Esxrnsrulu, SWEDEN, 'ASSIGNOR zro AxrIEEoLAGEr c. E

PAT NT OFFICE JOHANSSON, OF ESKILSTUNA, SWEDEN mcEoMErEa on. THE LIKE Application filed May 16,

This invention relates to improvements in micrometers, or the like.

In the use of micrometers and other gauging and measuring instruments designed for very accurate work, errors frequently arise due to the inability of the user to read accurately the necessarily fine graduations provided. These errors result, not from a lack of a correct understanding of the use of the instruments, but to the fact that the light reflection from the graduated area is often such as to render the graduations obscure.

The object of the present invention therefore is to remedy this defect by providing an instrument, the graduations or scales of which are visually distinct from the background thereof. This improvement is effected by treating those areas of the instrument, whic include the graduations, so as to render the areas dull in appearance, thereby enhancing the visibility of the graduations and reducing the likelihood of errors in the use of the device.

In the accompanying drawing, a micrometer embodying the present invention isillustrated. The micrometer may be of standard construction and will not be described in 1927. Serial No. 191,624.

on, the graduations and the background thereof being treated to dull the same to thereby uations.

2. A micrometer having graduations thereon, a portion of the surface thereof including said graduations being etched to provide a dull surface for the purpose of enhancing the visibility of said graduations.

In testimony whereof I have subscribed my name.

ERIK G. PEHRSSON.

detail, and, as shown in the drawing,- may have two sets of graduations 10 and-l1, the former being on the member 12 and the latter on the rotatable sleeve 13. The backgrounds of the graduations are treated to dull the surfaces thereof, as indicated at 14 and 15 in the drawing, which treated surfaces this desired result is by etching, although may be as extensive as desired and may in elude in some instances the usual figures as-' figures, although the figures may be placed k sand blastin or other methods may be used,

the technique of which methods will not be described herein. i

I In micrometers and related gauging or measuring instruments the scales or graduaccentuate the visibility of saidgrad:

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