US689978A - Planimeter. - Google Patents

Description

No. 689,978. Patented Dec. 3|, 1901.

, A. c. LIPPINCOTT.

PLANIMETER.

(Application filed Mar. 24, 1899.)

(No Model.)

2 Sheets$heet I.

@912 Z (9 t J- fine 'INVENTOH uORms wcrzns cc mom-urnq. WASNINGYON o No. 689,978. Patented Dec. 3|, I90l. A. c. LIPPINCUTT.

PLANIIIETER.

(Application filed Mar. 24, 1699.)

2 Sheets-Sheet 2.

(No Model.)

' INVENTOR w/msss'as ATTORNEY UNlTED STATEs PATENT @nrroa ALPHEUS O. LIPPINOOTT, OF NEW YORK, N. Y.

PLANIMETER.

SPECIFICATION forming part of Letters Patent No. 689,978, dated December 31, 1901.

Application filed March 24,1899. Serial No- 7l0,308. (No model.)

To ctZZ whmn it may concern:

Be it known that I, ALPHEUS O. LIPPIN- COTT, a citizen of the United States, residing in the borough of Manhattan, in the city, county, and State of New York, have invented new and useful Improvements in Planimeters, of which the followingisaspecification.

This invention has special reference to that type of planimeters in which the measuringwheel axis is substantially at right angles to the tracer-bar. In this type of planimeters the measuring-wheel has heretofore been mounted on a stationary shaft, so as to have rotative and longitudinal movement thereon. In order to secure the required free movement of the wheel on the shaft in said structures,a very loose fit of the wheel on the shaftis necessary, and said loose fit results in a degree of lost motion which, if not prevented, would render the action of the device wholly inaccurate; but it has been the practice to reduce said lost motion to a minimum by providing the wheel with a long bearing or hub, as shown in several of the figures of the accompanying drawings. The long bearing or hub necessitates the use of a shaft having compensating additional length and adds to the cost of the device. I have found that by mounting theshaftsothatitwillhavelongitudinalmovement in its hearings or bearing and mounting the rotative measuring-wheel thereon so that it will move longitudinally therewith all tend ency to lost motion is eliminated and the device will act with the greatest accuracy, while its cost is reduced. This idea constitutes one of the main features of the invention. In the accompanying drawings it is shown as embodied only in a construction wherein the shaft is provided with teeth which mesh with a gear that is connected with the movable member of an indicating means of the plainmeter. While this specific constructionis preferred and for this reason is made the subject-matter of specific claims, this part of the invention is not restricted to such embodiment.

In the use of planimeters in measuring indicator-diagrams, &c., it is necessary to adjust the length of the tracer-bar to the length of the diagram measured on a line parallel with the atmospheric line. In previouslyformed planimeters this requirement involved the necessity of erecting perpendiculars from the atmospheric line touching the abscissze or effective length of the card by means of a T-square and set-square. This operation involves a loss of time, to eliminate which is another of the objects of the invention. This object is accomplished by providing the extensible tracer with a gage or gages,(preferably one contiguous to the frame and another at the outer end of the bar,) which project laterally therefrom a sufficient distance to touch the abscissze. In the use of this gage, taking an indicator-diagram as an example, it is only necessary to adjust the length of the tracer-bar so that the gages are positioned to coincide with the extreme ends of the diagram, taking care that the tracer-bar is parallel with the atmospheric line of the diagram. This simple means wholly eliminates the labor and loss of time incident to the erection of perpendiculars. Preferably the gages are pivoted, whereby they may be turned out of the way when not in use.

In previously-proposed planimeters of the type hereinabove referred to the measuringwheel and scale have been arranged adjacent to each other and with the scale extending along the line of longitudinal movement of the wheel. This does not permit the reading of more than onefactata time. In said constructions the wheel serves as the movable member of the indicating means, and as it frequently becomes bent out of true, which renders the indication inaccurate, it is desirable to provide a structure-in which the measuring-wheel will not serve as the movable member of the indicating means. To these ends I have produced a structure embodying a dial and a pointer, one movable relatively accuracy of the indication and also that the construction permits the use of a dial having a series of scales showing different but related facts and of a hand or pointer provided with a plurality of arms having verniers, thus improving the device in very important particulars. The gearing which connects the measuring-wheel with the movable member of the indicator preferably includes a rack, which is movable longitudinally through the frame and is guided thereby, and a toothed wheel attached to the movable member of the indicator and intermeshed with said rack. In the form of device havinga measuring-wheel rotative on a fixed shaft one end of the rack is so connected with the wheel as to partake of the longitudinal but not of the rotative movement thereof, and in the form of device havingits measuring-wheel carried by a shaft having longitudinal movement the rack is preferably formed on said shaft.

A further aim of the invention is to provide a construction of planimeter which may be packed in most compact form. To this end the fulcrum-bar and the tracer-bar are each made in sections, so that each may be lengthened and shortened, and each is pivoted at one end to the frame. This construction is also advantageous in that it permits both bars to be adjusted to the length best suited for the particular work at hand. Pivoting the tracer-bar to the frame introduces an additional desirable feature, as it enables an expert user of the device to compensate for inaccuracies in the diagram by throwing said bar out of its normal position at right angles with the measuring-wheel.

Figure 1 is a plan of one form of my improved planimeter.- Fig. 2 is a side elevation and partial vertical section on the plane of the line 2 2 in Fig. 1. Fig. 3 is a plan showing a movable dial and fixed pointer. Fig. 4 is a side elevation and partial vertical section of the same on the plane of the line 4 4 in Fig. 3. Fig. 5 is a plan view of a modified form, with the grad nations and pointer and the fulcrum-bar and tracer-bar omitted. Fig. 6 is an enlarged detail view of the pointer, showing the verniers thereon. Fig. 7 is an enlarged detail of the means of attaching and adjusting the indicators on the tracer-bar. Fig. 8 is aside elevation and partial vertical section of the same on the plane of the line 8 8 in Fig. 7. Fig. 9 is an enlarged side elevation of a portion of the wheel, showing the nature and position of the groove 10. Fig.

. 10 is a side elevation and partial vertical section of a form of the fulcrum-bar when the to rotate freely thereon.

At the rear of the frame is located a tracer-bar t, which preferably is pivotally secured thereto, as seen at j, so that it may be swung away from the wheel to a position substantially or approximately at right angles to the axis of the rack 1'. It is preferable to construct the pivot j in the form of a thumb-screw having a threaded lower end to engage the tracer-bar and a smooth upper end to engage the pivot-hole in the frame, so that when the screw is loosened said bar may be adjusted pivotally and when the screw is tightened down upon the frame it will retain the tracer-bar in adjusted position, and said screw may have a milled head for convenience in manipulating it. The tracer-bar is provided with the usual tracingpin 6 Also at the rear of the frame is pivotally secured, at 19 the fulcrum-bar I), having the pin b.

The wheel to consists of a disk 10 of suitable size and having a slightly-rounded edge 10 to facilitate its freedom of movement, and if mounted to move on the shaft is provided with a hub 10 made relatively large as compared with the size of the disk w to prevent lateral displacement on the shaft 8.

The rack 1" and the hub 10 are connected by any suitable coupling 0, which will communicate the longitudinal movement of the wheel to on the shaft 8 to-the rack. In the form of instrument illustrated in Fig. 1 I have shown this coupling asconsisting of a collar 0, secured to the rack by a lug c and fitting into a groove 10 on the hub U13. Any other suitable form of coupling may, however, be employed without departing from the principle of my invention.

The rack 0" slides not only in the groovef' in the frame f, but also passes through an aperture d in the side of a dial-box d adapted to incase and support the dial cl and pointer 19. In the bottom of the box is made a bearing 19, adapted to receive the lower end of the pointer-shaft 19 to which is rigidly attached by any suitable means a cog-wheel p adapted to mesh with the rack r and to be rotated by it. At the top of the box is secured the dial d beneath the pointer. The dial is provided with a plurality of concentric graduations d 61 61 &c.-, spaced in terms of different but interdependent notations, so that different but related facts may be simultaneously or successively read from anyone position of the dial and pointer. For instance, scale (i may he graduated in terms of area in English measures, scale 61 may he graduated in terms of area in French measures, scale 01 in terms of weight, so that if a hide were measured by the use of the instrument its area and its weight might be simultaneously read. Of course this is assuming that a hide would be of uniform thickness and density and that its weight would thereby become a function of the area. As a planimeter, in fact, can only registerthe linear displacement of the wheel, the scales on the dial must be graduated in terms which are functions of such linear displacement. With this principle in view any number of scales may be devised and placed upon the instrument.

The pointer 19 is provided with one or more wings or arms 19 1 &c., carrying verniers which are adapted to be used in more accurately reading from the scales on the dial, the verniers being placed on the pointer to correspond in position and notation with the scales which they assist in reading.

The barf is composed of a tube which has its inner end preferably soldered or otherwise fixed in asocketflthrough the solid portion of which the pivot j extends,and toward its outer extremity at 15 said tube is split and adapted to contain a smaller tube or rod 25 which may slide in and out of the larger tube i, so as to vary the effective length of the tracer-bar t. I provide means, as a collar or two lugs and thumb-screw 25 for securing the extensionrod 15 in place after adjustment, and I also prefer to locate a washer i between the socket i and the frame f.

One or more gages, as v, t", are provided for the purpose of accurately measuring the length of an object placed beneath them, so that the effective length of the tracer-bar may be adjusted thereto without requiring the erection of perpendiculars, as hereinbefore stated. Two such gages are preferably employed. In the construction shown in the accompanying drawings and preferred by me one of the gages t" is pivoted by the tracingpin t to the end of the tracer-bar and has a slotted wing t which coacts with a thumbscrew 2' to secure the gage adjustably and detachably to said bar, and the other gage 2' is suitably mounted on the frame contiguous to the pivoted end of the tracer-bar. In Fig. 1 I show in such position an indicator-card a, which if its area is to be ascertained must first be measured as to its length. This can be rapidly and accurately learnedby setting the bar within the tube 15, so that the inner edges of the gages 1; and t" coincide with the external lateral boundaries of the indicatorcard. The use of such gages has a considerable advantage over that which can be obtained by any mere graduation of the bar 1?, whereby its length could be ascertained, for the reason that as they extend from the bar they serve to measure the breadth of an object of considerable size placed beneath the instrument.

The fulcrum-bar b is rotatably secured to the frame f by any suitable means-for instance, by an ordinary pivot I9 I preferably provide it with meansfor instance, by making it of telescopic sections 6 and 6 as shown in Fig. 10, and providing it with a clampingscrewb whereby its length may be adjusted so the instrument may be used for measuring areas of various dimensions. I do not confine myself, however, to the telescopic form as the means for varying its length, because it may be made of folded parts or in any other Way well known to the art whereby the same purpose may be accomplished. It is quite obvious, provided the pointer p and the dial (1 are moved in relation to each other by the longitudinal displacement of the wheel w, that it makes no difference in the result or the eificiency of the instrument whether the pointer is movable and the dial is fixed or the dial is movable and the pointer is fixed. In Fig. 4 therefore I have illustrated the latter construction, in which the dial is shown as mounted upon the vertical shaft p and the pointer is shown as rigidly fixed in the dial-box. It is quite obvious that the rotation of the cog-wheel p in that case will rotate the dial and that the lateral displacement of the wheel w may be read by the extent of this rotation of the dial compared with the fixed position of the pointer. If the glass cover 9 is placed upon the dial-box, as shown in Fig. 2, an opaque line drawn across the box may serve for the purpose of a pointer without any material size being given to the latter.

In Fig. 5 I have illustrated a modified form of the planimeter, in which the wheel'axis and the rack are made integral. In this construction the wheel w is mounted upon the outer extremity of the combined rack and shaft 1) and secured in place by a set-screw i) or similar well-known means. The shaft is then made into a rack by being provided with a series of parallel annular grooves 21 These grooves are adapted to mesh with the cogwheel 19 precisely in the same manner as the rack 1- does, the longitudinal movement of the wheel in the direction of the axis of the rack being transmitted to the dial or pointer, as the case may be, in the manner heretofore described.

As the construction and method of use of a planimeter are well known to persons skilled in the art, and more particularly to persons acquainted with the manner of using mathematical instruments, I will not explain the manner of using the device in reading the graduations upon the dial.

The advantages of my invention will be quite obvious to those skilled in the art to which it appertains. The adjustability of the tracer-bar and the ability to secure it firmly in position after adjustment, its rotatability, so that when not in use it may be turned in toward the shaft of the wheel and so kept within a small compass, the adj ustability of the fulcrum-bar, whereby the range of use of the instru ment is greatly increased, the ability to read different but related facts from the multiple graduations upon the dialface and to secure unquestioned accuracy of the reading by the use of the verniers upon the pointer, and the steadiness and accuracy of operation of the instrument all serve to make a planimeter which in my opinion marks a decided advance in the art.

What I claim as new is- 1. A planimeter, having the shaft of its ro- ICC tative measuring-wheel mounted to move longitudinallyin its bearing and said measuringwheel mounted on said shaft so as to impart longitudinal movement thereto and move .longitudinally therewith, for the purpose specified.

2. A planimeter, having, in combination, a frame, an indicator carried-by said frame and having a movable member, a rotative and longitudinally movable measuring wheel, and connecting devices for imparting the longitudinal movements of said measuringwheel to the movable member of the indicator, whereby the indications are accurate even though the rim of the measuring-wheel be bent irregularly, as specified.

3. A planimeter, having, in combination, a tracer-bar, a frame attached thereto, an indicator carried by said frame, said indicator embodying a dial having a series of scales and a pointer having a plurality of verniers, a measuring-Wheel having both rotative and longitudinal movements and located at a distance from the indicator, and interengagcd gearing devices, one of which moves longitudinally through the frame" under the influence of said measuring-wheel, and another of which devices is located in the indicator and connected with the movable member thereof, substantially as described, whereby the indication will be accurate even though the rim of the measuring-wheel be bent irregularly and a plurality of indications of different facts are simultaneously disclosed, as specified.

4. A planimeter, having, in combination, a longitudinally-movable shaft, a rotative measuring-wheel which imparts longitudinal movement to said shaft, and an indicator embodying a dial and a pointer, one movable relatively to the other, the movable member of said indicator being connected with said shaft and actuated by the longitudinal movement thereof.

5. A planimeter, having, in combination, an indicator embodying a dial and a pointer, one movable relatively to the other, a shaft capable of both rotary and longitudinal movem'en ts in its bearing and provided with teeth, a gear engaged with said teeth and connected with the movable member of the indicator, and a rotative measuring-wheel controlling both of said movements of said shaft.

6. A planimeter, having, in combination, an indicator embodying a dial and a pointer,

one movable relatively to the other, said dial having a plurality of scales showing different but related facts and said pointer having a plurality of verniers, a rotative and longitudinally-movable measuring-wheel, and connecting devices for imparting the longitudinal movements of said measuring-wheel to the movable member of the indicator, substantially as described and for the purposes set forth.

7. In a planimeter, the combination with a fulcrum-bar rotatably secured to the frame and provided with means for adjusting its length, of a tracer-bar rotatably secured to the frame and provided with means for adjusting its length, a measuring-wheel and means for reading the extent of the longitudinal displacement of the wheel when rotated, in any desired notation.

8. In a planimeter, the combination with a rotative and longitudinally-movable measuring-wheel, means for indicating the extent of movement of the wheel, and a tracer-bar, of a gage projecting laterally from said bar in a direction approximately parallel with the plane of the longitudinal movement of said wheel, to obviate the necessity of erecting perpendiculars, as specified.

9. In a planimeter, the combination with a rotative and longitudinally-movable measuring-wheel, means for indicating the extent of movement of the wheel and a tracer-bar adjustable as to length, of a plurality of gages projecting in a direction approximately parallel with the plane of thelongitudinal movement of said wheel,one of said gages being pivotally connected with the bar, substantially as described and for the purposes specified,

10. A planimeter, comprising a tracer-arm, a measuring-wheel whose axis is perpendicular to said tracer-arm and along which axis the wheel is capable of movement, a spindle upon which said wheel is mounted and which is adapted in the operation of the instrument to have a movement perpendicular to the tracer-arm, and a scale for indicating the movement of the measuring-wheel along the axis of the wheel.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

ALPHEUS O. LIPPINCOTT.

Witnesses:

CHESTER H. HIGGINS, B. M. SooTT.

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