C, B, RICHARDS, Steam Engine Indicator, No, 3790 Patented March 24, 1863,

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C. B. RICHARDS, OF HARTFORD, CONNECTICUTT, ASSIGNOR TO C. T. PORTER, OF NEW YORK, N. Y. IMPROVED STEAM-ENGINE INDICATOR.

Specification forming part of Letters Patent No. 37,9s0, dated March 24, 1863. To all whom it may concern: or an equivalent therefor, so arranged as to Beit known that I, C. B. RICHARDs, of cause the pencil's point to travel in a straight Hartford, in the county of Hartford, in the line, substantially in the manner hereinafter State of Connecticut, have invented a certain clearly set forth. new and useful Improvementin Steam-Engine To enable others skilled in the art to make Indicators; and I do hereby declare that the and use my invention, I will proceed to a de following is a full, clear, and exact descrip scription thereof, tion of the same, reference being had to the In the accompanying drawings, a is a cy accompanying drawings, making part of this lindrical case containing a small steam-cylin specification, and to the letters of reference der, b, in which moves a piston, c, the move. marked thereon, in which ments of which are regulated by a spiral Figure 1 is a plan of the instrument. Fig. spring, d. These parts are constructed and 2 is a side elevation of the same. Fig. 3 is a arranged in a manner similar to, but are much vertical section through the center of the shorter than, the corresponding parts of an spring-case A, and Figs. 4, 5, and 6 show parts ordinary McNaught indicator, making deline of the instrument in detail. ations on the same scale. To the outside of Similar letters of reference denote the same the case a is secured a ferrule, e, an arm from parts in the several figures. which supports a cylindrical paper-holder, f, My invention relates to an improvement in which in construction and arrangement is apparatus for indicating and delineating the similar to the paper-holding drum of a Mc action of steam in the cylinder of a steam en Naught indicator, and it receives the proper gine. The form of steam-engine indicator in reciprocating movements in the same man most general use is that commonly known as ner. Around the upper part of the case a the “McNaught indicator,” in which the pis is a ferrule, g, to which are attached two arms, ton and its guiding-rod have the same range h and i, one of which, i, supports the fulcrum of motion as the pencil; but as the piston pink of a light lever, l, the extreme end of and rod are necessarily made quite heavy, which lever is jointed to the end of a lever or and their range of motion extensive in order link, m, the opposite end of which is jointed to produce delineations on a sufficiently-large to the extremity of a delicate lever or radius scale, the momentum of these parts is so great bar, m, the fulcrum-pin 0 of which is support as to render the instrument unserviceable for ed by the arm h. To the lever l, at a point application to engines having rapid move distant from its fulcrum k about one-fourth of ment. While, therefore, it is desirable to re the length of the lever, the rod p of the pis duce the momentum of the parts which are ton c is connected, by meals of a forked link, moved by the varying pressures of the steam, q, which is jointed to a knuckle, ), secured to it is also desirable that the pencil or marking the upper end of the rod p). In the center of point should move in a straight line, in order the link n is a holder for the pencil S, which that its delineations, which should be on a receives from the piston c through the lever l large scale, may readily be measured with ac a range of perpendicular motion about four curacy, and in order, also, that the paper on times greater than that of the Said piston, and which the delineations are made may be the levers l and n are so proportioned and clamped in the usual manner around a cylin their fulcra are so adjusted that the marking drical drum, to which the requisite movements point of the pencils is caused to move in a can be readily given by the customary means. straight line in the same manner that the To furnish an instrument possessing the “parallel motion” of a steam-engine causes above-mentioned desirable features is the Ob the end of the piston-rod to move in a right ject of my invention; and to this end my said line. The movements of the levers are indi invention consists in the employment of a le cated in Fig. 2 by red lines. ver or its equivalent so connected with the The application and mode of (using my im pencil and the piston as to give to the pencil proved indicator are essentially the same as a range of motion greater than that of the of McNaught's instrument, and need no de piston, in combination with a system of levers, scription. Although I have described the 2 37,980 movement of the listol as being all) () ut one |ily measured with accuracy than those pro fourth that of the pencil, yet in soule cases it duced by a pencil moving in a curved path. may be desirable to give a relative movement I am aware that in an indicator invented by to the piston less than that specified, as in Gcogh, and described in works on the steam the case of engines with very rapid recipro engine, the piston has a motion less than that cating movements, and in which the steam is of the pencil, but the pencil moves in an arc cut off early in the stroke. The pencil may of a circle and records its indications on paper be guided in a straight line by a slide at moved over a flat surface by complex mech tached thereto and moving in straight guides, anism. I therefore disclaim the use of differ instead of by the parallel motion described. ent relative movements of the piston and By reducing the range of movement of the pis pencil when the pencil's point moves in a ton, its rod, and the spring, the Weight and curved path; but momentum of these parts, which are necessa What I claim as my invention, and desire rly made of considerable strength, are much to secure by Letters Patent, is reduced. The pencil, though it has a long The means, substantially hereinbefore de range of motion, and consequently makes its scribed, for giving to the marking-point a indications on a desirably-large scale, has but range of motion greater than that of the pis little momentum, because of its extreme light ton by which it is actuated, in combination ness and the lightness of the levers which with the described means, or an equivalent give it motion. The movemelt of the pen therefor, by which the marking-point is caused cil’s point in a straight line permits the use of to travel in a straight line, substantially as a cylindrical paper-holder, which is the most and for the purposes herein before specified. compact, convenient, and easily operated of any of the devices which have been contrived C. B. RICHARDS. for presenting the paper to the action of the Witnesses: pencil. The delineations made by a pencil FRANCIS FELLOWEs, moving in a straight line are much more read FRANCIS FELLOWEs, Jr.