US 399167 A
Description (OCR text may contain errors)
(ModeL) L. S. STARRET'T.
MIGROMETER GALIPER SQUARE.
Patented Mar. 5
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UNITED STATES IJAROY S. STARRETT, 0F
ATHOL MASSA Cl-IUSETTS.
SPECIFICATION formingpart of Letters Patent No. 399,167, dated March 5, 1889.
Application filed February 1, 1888. Serial No. 262,624 (Model) To aZZ whom, it may concern.- 7
Be it known that I, LAROY S. S'IARRE'PI, of Athol, in the county of ll'orcesler and State of Massachusetts, have invented a new, use
j aw adjustable by a micrometcr-mit, whereby subdivisions of such fractional parts of the unit of measure may be accurately ascertained. The instrument has also a movable binding-clasp recessed to receive the micrometer-nut, and is 'l'urnisheifl with a sprin extending from clasp to jaw and surrounding the screw on wh ich the nut works. This spring takes up all backlash and limits the force with which the movable jaw is pressed by the nut against the work to be measured.
My invention consists in the described instrument as an article of manufacture, and in the combinations of devices set forth in the appended claims.
In the drawings, Figure 1 is a side view, on an enlarged scale, of my improved instrument complete. Fig. 2 is a transverse section at as as, Fig. 1, made on a smaller scale. Fig. 3 is a detail in perspective.
A is the blade or beam, (shown in Fig. 1 as graduated to fortieths of an inch or other unit of measure.)
B is the fixed jaw, exlcmling from one end of the blade at a right angle thereto. Adjoining the fixed jaw B is the sliding jaw C D E, the part 0 being the jaw proper, which acts with the jaw 13 as a caliper. The part D is a flat sleeve entirelysurrounding the beam, and is furnished with a set-screw, F, in the usual manner. A headed bearing-plate, G, is interposed between the point of the screw and the edge of tho blade. The movable jaw is formed with a grooved projecting part, E, which receives one edge of the beam, and is beveled down to an edge along the line of graduations on each side thereof, thus affording an accurate reading of the markings and holding the jaw against an y lateral play. movable jaw, and surrounding the blade, is the usual sliding binding-clasp, K, recessed at its lower end to receive a milled nut, N, which Adjoining the a F engages with the threads of a screw-rod, B, projecting from the movable jaw and passing through aperforation drilled edgewise through the clasp. A spiral spring, S, surrounds the screw-rod R, and is held under compression between the jaw and clasp, thus serving to take up all backlash between the clasp K and nut N, and also between the threads in nut N and screw R, and limitin the pressure against the work to the strength of the spring. Y I In practice thenut-X will be of slightly less width than the recess in which it works, so that when the jaws have come in cont act with the object to be calipcrcd a slight reverse movement of the nut-a partial revolutioni will hold the tension oi the spring without moving the jaw. I
The nut N has a cylindrical micrometer portion, M, grad ual ed in twenty-five equal divisions, the lines of subdivisions coming suc cessivcly opposite a fixed mark on the clasp. Now, since a co mplcte rotation of the nut slides the movable jaw the fortieth part of an inch in the instrument here shown, it follows that turning such nut the twenty-fifth part of a revolution will move the j aw one twenty-fifth of one-fortietl1-tl1at is, the thousandth part of an inch-end so on for any number of thousandths.
I claim as my invention 1. The described micrometer caliper-square, consisting of a graduated blade or beam, A, with a fixed jaw, B, and movable jaw C D E, in combination with an adjustable bindingelasp, K, micrometennut M N, threaded rod R, and surrounding spring S, substantially as set forth.
2. In a measuring-instrumen t, a graduated blade, a movable jaw, and an adjustable binding-clasp on said blade, in combination with a screw-rod extending from the jaw to the clasp, a spiral spring embracing such rod, and a micrometer-nut engaging such screw, substantially as set forth.
In testimony whereof I have si good my name to this specification, in thepresence of two subscribing witnesscs, on this 26th day of January, A. l). 1888.
\Vitnessesr J AMES H. Pom), BURNSIDE E. SAwr R.