US946268A - Micrometer. - Google Patents

Description

D. PETERS.

MIOROMETER.

APPLICATION FILED MAR. 16, 1909.

946,268. Patnted Jan. 11,1910.

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ATTORNEY.

UNITED STATES ATEN F TE.

DAVID PETERS, 0F JERSEY CITY, NEW JERSEY.

MICROMETER.

Specification of Letters Patent.

Patented J an. 11, 1910.

To all whom it may concern:

Be it known that 1, DAVID PETERS, a citizen of the United States, residing at Jersey City, New Jersey, have invented certain Improvements in Micrometers, of which the following is a specification.

This invention relates more particularly to the reading of micrometer screws, and the objects of the invention are to avoid in such reading the necessity for any addition of various numbers or readings; to thus render reading of the micrometer easier and quicker; to lessen the liability of making errors in reading a micrometer, and to obtain other advantages and results as may be brought out in the following description.

Referring to the accompanying drawings, in which like numerals of reference indicate corresponding parts in each of the several figures, Figure 1 is a side view of a micrometer of my improved construction showing a reading of seven hundred and ninety nine thousandths, and Fig. 2 is a similar View showing a reading of eight hundred and one thousandths; Fig. 3 is a side view of the portion of the micrometer as shown in Fig. 2, with the barrel developed or spread out flat.

In said drawings, 101 indicates the U- shaped body of the micrometer, having a sleeve 102 in which the usual micrometer screw 103 works toward and away from an anvil 104 on the body. On the said sleeve 102 is a longitudinal line 105, across which are marked graduations, the smallest of which are each twenty-five thousandths and every fourth one being numbered, so that the series of figures on said sleeve from 1 to 10 indicate each one-hundred thousandths. Upon the said sleeve 102 is a barrel 106 which rotates to turn the micrometer screw 103 as is usual. It is in certain novel features of this barrel 106, next to be described, that the present invention more particularly inheres.

The barrel 106 is provided at its end which incloses the sleeve 102, with a circumferential series of longitudinal lines or graduations, each one representing one thousandth. There are twenty-five of these lines around the barrel 106, and thus any one of them in the course of a complete revolution of the barrel travels longitudinally of the sleeve 102 the distance of one of the smallest graduated divisions thereon. One of these longitudinal lines on the barrel, the one which should coincide with the longitudinal line 105 on the sleeve at a reading of an even number of hundreds of thousandths, as 107 in the drawings, is selected as the starting point for a spiral column 111 which extends four times around the barrel 106 and thus provides a series of spaces to receive numbers from 1 up to 100, as shown.

The end of the barrel 106 which overlaps on the sleeve 102 is shaped on a spiral, as at 108, the ends of said spiral being on the zero line 107 of the barrel, so that at said zero line a step 109 is formed. This step is so located and of such length that when the zero line 107 on the barrel 106 coincides with the longitudinal line 105 of the sleeve, the high part of the step or extremity of the reading line lies between the ends of a subdivision of the sleeve, and the'low part is between the ends of the next covered subdivision. Thus in turning the barrel, the extremity of the reading line at any time lies intermediate the ends of a subdivision and never on the dividing lines of said subdivisions, changing suddenly from one subdivision to the next wherever the zero line 107 of the barrel crosses the line 105 of the sleeve. The number of the subdivision of the larger divisions of the graduation on the sleeve 102 in which the longitudinal reading line of the barrel 106 terminates at the end of the barrel indicates the number of the transverse column of the barrel 106 from which the tens and units of thousandths are to be read. Such tens and units can be read at a glance, and by prefixing thereto the figure of the last visible hundreds of thousandths line on the sleeve102, a complete reading is had. For example, in Fig. 1 the longitudinal line 112 of the barrel coincides with the line 105 of the sleeve and therefore is the reading line. The end of this line terminates at the extremity of the barrel in the fourth subdivision of the seventh division on the sleeve. Hence we take with the figure seven the number which is in the fourth spiral column of the barrel, next above the reading line 109, which is ninetynine, and so have at once the reading seven hundred and ninety nine. Again, in Fig. 2 the longitudinal line 110 of the barrel is the reading line, and the end of this line at the extremity of the barrel lies in the first subdivision beyond the eighth division on the sleeve 102. We therefore read from the first spiral column the unit one, which with the eight hundreds on the barrel makes the whole reading eight hundred and one.

Obviously the numbers in the spiral columns, instead of being stamped directly above the longitudinal reading line of the barrel as shown, could be stamped on or across said lines, or the lines broken to receive said numbers, as is common in marking rules and the like.

It will be understood that the sleeve 102 is fast to the body 101 of the micrometer and that the screw 103 works therein as usual in micrometers. The barrel 106 is fast to the screw 103, enabling said screw to be turned, and said barrel partially telescopes the sleeve 102, all as is also common and wellknown in micrometers.

Having thus described the invention, what I claim is:

1. In a micrometer, the combination with a sleeve having a longitudinal line and a series of divisions and subdivisions along said line, of a barrel partially telescoping said sleeve, said barrel having longitudinal lines forming as many graduations of its circumference as make one of said subdivisions on the sleeve and a spiral line cutting said longitudinal lines into as many columns as there are subdivisions in one of said divisions on the sleeve, the divisions on the sleeve being numbered consecutively and said graduations on the barrel being numbered consecutively through the spiral columns as part of one of the said divisions,

the said longitudinal lines of the barrel extending to the extremity of that end of the barrel inclosing the sleeve and adapted thereat to be brought into coincidence with said longitudinal line of said sleeve.

2. In a micrometer, the combination with a sleeve having a series of longitudinal divisions and subdivisions, of a barrel on said sleeve having a series of circumferential graduations divided into as many spiral columns as there are subdivisions in one of the said divisions on the sleeve, each column containing as many graduations as make one of the said subdivisions, the divisions on the sleeve being numbered consecutively and said graduations on the barrel being numbered consecutively through the spiral columns as parts of one of said divisions, the extremity of said barrel inclosing said sleeve being formed on a spiral whose ends terminate in the zero line of said circumferential graduations of the barrel.

8. The combination with a micrometer screw, of a sleeve having a series of longitudinal graduations, and a barrel on said sleeve having a series of circumferential. graduations, the extremity of said barrel iiiclosing said sleeve being formed on a spiral whose ends terminate in the zero line of said circumferential graduations of the barrel.

DAVID PETERS.

In the presence of CHAS. P. DAY, RUssELL M. EVERETT.

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