703. Patented Oct. 17, 1893

(No Model.) ' ` J. H. LYNCH-_ VERNIER GALIPBRS. N0. 506 ,703. Patented Oct. 17, 1893.

i‘l'. ESSEE l Ä UNITED , STATES PATENTy OFFICE.

JOHN HENRY LYNCH, OF LOWELL, MASSACHUSETTS.

SPECIFICATION forming' part of Letters Patent No. 506,703, dated October 17', 1893. Application filed May 23, 1893. Serial 110.475.234. (No model.)

To all whom ¿t may concern,. and the bushingF is secured in the sleeveA Be it known that I, JOHN HENRY LYNCH, a by a screw I which passes radially through a citizen of the United States, residing at Low countersunk hole a4, inthe side of said sleeve 55 ell,in the county of Middlesex and Common and enters a correspondingly screw-threaded wealth of Massachusetts, haveinvented acer hole f7 in the middle section of the bushing tain new and useful Improvement in Vernier F, diametrically opposite the longitudinal Calipers, of which the following is a speciti slot f3. The end sections of the bushing F cation. are counterbored and may slip on the bar M My invention relates to vernier calipers when the jaws f4 f5 are slightly opened. and consists in the combination, in a caliper, Midway between the ends of the slot f3 is of_a bar or measuring-rod, provided with a shown an inwardly tapering hole f6 formed spiral, a non-rotary circular scale and a cir equally in the jaws f4 f5, and concentrically -cular Vernier adapted to slide on said bar and with said hole f6 a screw-threaded hole d3 is 65 to be rotated by said spiral, and in the other formed in the sleeve A. In the hole d3 is combinations and devices hereinafter de screwed an externally threaded guide-sleeve scribed and claimed. J through which extends a pin K, having In the accompanying drawings, Figure lis an enlarged conical head k at the inner end a plan of a caliper containing my improve of said guide-sleeve, which head lo may be 70 ment; Fig. 2 a side elevation of the same, pressed into the hole f6 to open the jaws showing the sleeve, bushing and tube in cen f4 f5, said enlarged head k preventing said tral section on the line 2 2 in Fig. 1; Fig. 3 a head lo from being lost out of said guide rear elevation of the same; Fig. 4, a section sleeve and rendering it necessary that said on theline 4 4 in Figs. 2 and 3 ; Fig. 5, a front pin should be placed in said guide-sleeve be 75 or rear elevation; Fig. 6, a bottom view and fore the the latter is screwed into the hole a3. Fig. 7, a side elevation of the nut which slides Adisk or button 7e’ may be riveted on the on~ the grooved bar or measuring rod and outer end of the pin K, to receive the press causes the rotation of the Vernier; Fig. 8, an ure of the finger. When pressure is removed end elevation and Fig. 9, a side elevation of from the pin K the elasticity of the jaws f4 the clamping bushing. f5 causes them to approach each other and A is a sleeve which surrounds the gradu forces the conical head lo out of >the tapering ated bar. or measuring rod M and may be hole f6. ' moved thereon t0 vary the distance between The clamping bushing F is provided with the outside caliper jaws B B' respectively se two> internal longitudinal ribs f8 which are 85 cured to said sleeve A and bar M. Said represented as round in cross-section, but sleeve A and bar M are also provided with which maybe V-shaped or semi-elliptical and inside caliper jaws C C', as shown in Figs. 2 these projections f8 enter and íit two corre and 3, in a well known manner. The sleeve sponding grooves m, formed in the bar M di A is not in direct contact with the bar M, ametrically opposite. each other, allowing the 90 the latter being surrounded by a clamping bushing F and jaw B to be moved on the bar :1.0 bushing F and a vernier carrying-tube E, ar M longitudinally, but prevent said bushing ranged within said sleeve A. and jaw from turning on said bar. The bushing F is of the form .shown in The bar M or measuring rod is graduated Figs. 2, 4, 8 and 9, the upper end of its cen in inches, from the jaw B', as indicated at m3, tral opening flaring, at f, to receive the lower in the usual manner, and the sleeveAis pro 45 end of the tube E and said _bushing being in vided at the end farthest from the jawB with two places cut nearly, but not quite through, a graduated circular disk or scale a, rigidly at f’ f2. The middle section of the bushing secured to said sleeve A, said scale ct being is slotted, at f3, through from cut f’ to cut beveled for a space from its edge all the way IOO f2, at equal distances from the ends of said around, as shown at a', and this beveled sur- _ 50 cuts, forming two equal spring clamping face is divided into one hundred equal divis jaws f4 f5, adapted to grasp the bar M and ions. This end of the sleeve A is counter prevent its movement in said j awed section, bored and threaded at a2 to receive an annu 2 506,703

lar nut D which nut may be provided with of the nut G, the indicated dimension being slots or holes in any well-known manner, to» read olf »on> the 4scale a and Vernier II, from enable it to be adjusted by means of a span right to left, or in the opposite direction from 70 ner wrench. The inner diameter ot' the nut that indicated by the arrow on said Vernier, D is the same as that of the sleeVeA and the said arrow showing the direction in which lcwerinner edge or corner of said nut is bev said Vernier I-I turns when measuring exter eled to tit a correspondingly beveled collar e nal andinternal diameters. Theinside cali onthe Vernier-carrying tube E and said ver per jaws are each one tenth of an inch wide 75 nier-carrying tube E, while turning freelyin and therefore two tenths of an inch should be the sleeve A, is prevented from longitudinal added to the indicated dimension in making movement in said sleeve by the bushing F and internal measurements. A metal case might said nut D. The upper end of the tube E is be used to cover the upper end of the meas slotted longitudinally, at e', to allow said up uring-rod M, litting tightly on the flange g4. per end of said tube to be expanded and also to The advantage of the herein described cir enable a spanner to be applied to said tube, to cular Vernier calipers over the ordinary right hold the same while the nut G is being secured line Vernier calipers, is that the scales can be therein. The nut G is provided with an ex made larger and therefore more easily read ternal screw-thread g which engages a screw in the former, without making the scale and 85 thread e2 in the tube E, the internally-screw Vernier unduly large and cumbersome and threaded portion of said tubeE being’slightly Vavoiding the necessity of using a microscope smaller than the corresponding portion of the or magnifying glass. To measure with a right nut G, so that when said nut is screwed into line Vernier and scale to the one ten-thou said tube, said tube is slightly expanded and sandth of an inch by having one hundred di 90 fills the central aperture‘of 'the Vernier H. visions to the inch on scale and having ninety 25 The Vernier H is a circular disk of a di nine of them for the sum of those on -the Ver ameter equal to the flat or unbeveled upper nier would require a microscope to read an surface of the scale a and at its outer edge is indicated measurement, or, if the inch on the beveled at h2 at the same angle with the bevel beam were divided into the Visible fortieth of 95 a’ of the scale or disk a. On the beveled sur an inch, which is about the size ofthe divis 30 face h2 an angular space equaltc that occu ions in the circular Vernier shown, it would pied by ninety nine divisions of the scale a require two-hundred and forty-nine fortieths, is divided into one hundred parts, so that, or over six inches in length for the Vernier. one ten-thousandth part of a revolution of The advantage which my device has over IOO said Vernier, or one ten-thousandth part of a the ordinary micrometer calipers, adapted to 35 complete circle may be read by means of said measure to the same degree ot accuracy, is, ` scale et and Vernier H. The Vernier H is that in my device the measurement can be counterbored underneath, at h, to admit the ‘ read by looking at one place on the Vernier, nut D, and has an annular projection h', pro whereas with the micrometer calipers it would 105 vided with a slot h3 to receive a spanner, to be necessary to look in two places, that is, on enable the Vernier to be adj usted on the tube E. the graduatedy bar and on the rotary sleeve. The bar or measuring-rod M is provided with ` Furthermore my instrument can be immedi two diametrically-opposite spirals or grooves ately adjusted to the distance to be meas m’ which grooves may be V-shaped, semi-cir ured, while the micrometer must be set by IIO cular or semi-elliptical in cross-section. The slowly turning a screw. 45 pitch of the spiral grooves m’ is one inch, as The scale a’ and Vernier H,of course, might represented, and the nut G is provided with be graduated to the metric system. - two internal spirals or screw-thread sections I claim as my invention- . g2 of a correspondingl pitch and adapted to 1. The combination, in calipers, of a bar 115 enter the spiral grooves m’ in the bar M, so or measuring rod, provided with a spiral, a 50 that, when the sleeve A and with it the tube non-rotary circular scale and a circular Ver E, Vernier H, and nut G are moved longitudi nier adapted to slide on said bar and to be nally on the bar M for the space of an inch, rotated by said spiral, as and for the purpose said tube E and Vernier H will make one com speciíied. plete revolution. For convenience in form 2. In calipers, the combination of the bar 55 ing the spiral or grooved sections g2 the nut or measuring-rod, having a jaw fixed thereto G is cut away, at g3, between said sections, and having a spiral, a movable jaw, a sleeve, and said nut G has also a flange g4 having a secured to said movable jaw and adapted to slot g5 to receive a spanner, to enable said slide on said bar, a circular scale, fixed on 125 nut G to be screwed into the tube E. A stop said sleeve, a tube, capable of rotation in said screw N having a head n, the diameter of sleeve but prevented from longitudinal move which is equal to the greatest diameter of the ment therein and rotated by the movement bar M serves as a stop, to close the ends of of said sleeve on said bar, anda circular Ver the grooves m m’. The bar M is also gradu nier, fast on said tube, as and for the purpose 13a ated from the upper end in inches, enabling specified. ' 65 the instrument to be used for a depth gage, 3. In calipers, the combination of the bar, the distance being taken from the outside of a sleeve, adapted to slide thereon, springjaws, the head of the stop-screw N to the flange g4 secured in said sleeve and adapted to grasp 506,703 said bar and to prevent a movement of said >bar is provided, to `prevent said movable jaw j sleeve on saidbar, and a wedge, carried by from turning on said bar, a circular scale, se said sleeve and adapted to be pushed between ‘ cured on said sleeve, a tube, arranged to turn said jaws, to force them apart andl release within said sleeve and having an external an said rod, as and for the purpose specified. nular flangev or collar, an annular nut, ar 4. In calipers, the combination of the bar, ranged in a screw-threaded counterbore, with a sleeve, adapted to slide thereon, spring jaws, which said sleeve is provided, to bear against secured in said sleeve and adapted to grasp the ilange or collar on said tube and to hold said bar and to prevent a movement of said said tube against the end of said bushing, sleeve on said bar, a tubular guide, secured said tube being provided at the end farthest 35 radially in said sleeve, a pin, arranged in said from said bushing with a. longitudinal slit, a tubular guide and'projecting from the out circular Vernier, surrounding said slitted end, side of said sleeve and having an enlarged and a nut, screwed-,into said slitted end, to wedge-shaped head, arranged within said expand said sleeve and to secure said Vernier sleeve and adapted to be pushed between said thereon, said nut having an internal spiral or jaws, to force them apart and release said screw-thread section, to engage a spiral with rod, as and for the purpose specified. which said bar is provided, as and> for the 5. In calipers, the combination of a cylin purpose specified. Y drical bar, having a jaw fixed thereto, a mov In witness whereof I have signed this speci able jaw, a sleeve, secured to said movable ñcation, in the presence of two attesting wit 45 jaw and adapted to slide on said bar, a split nesses, this 17 th day of May, A. D. 1893. spring-bushing, secured in said sleeve and ' ' JOHN HENRY LYNCH. adapted to surround said bar and provided Witnesses: with an inward projection adapted to enter ALBERT M. MOORE, and ñt a longitudinal groove with which said VNELLIE GOOD.