US2311804A - Curvometer - Google Patents

Description

Feb. 23, 1943. A. J. WRIGHT CURVOMETER Filed Oct. 12, 1942 I 2 Sheets-Sheet 1 INVENT OR.

Feb- 23, 1943 A. J. WRIGHT CURVOMETER Filed oct. 12, 1942 2 sheets-sheet 2 Patented Feb. 23, 1943 T11 TS A Aelvira-fo sr' CURVOMETER .Arthur 'J. Wright,

Dallas, Tex.

Application 0ctober 12, 1942, 5Serial No. 461,829

6 Claims.

This invention relates-to `apparatusor gaugmg curved bodies and more particularly to a curvometer especially vadapted for determining the concave and convex surfaces-of lensgrinding laps.

The principal object vof the invention is to provide alcurvometer lwherein is provided a plurality of cams, mounted on ka common shaft, each bearing the-same radiuscircle and predeterminately spaced apart and `arrangedon-said 10 shaft -so that the lines of each right-'angle design of the cams are -respectively parallel. Moreover, the yinvention provides for `the Ysetting of the cams through the medium of a manually actuated dial, suitablycalibrated for minute set- 15 ting and after having been set, the-cams afford stops for an equal number of spring controlled, longitudinally movable prongs -or Yfingers, Vwhose movement into contact "With the peripheries of the cams is effected Aby the Work itself in the 120 process of defining the curve thereon which is accomplished when the curve -of the work lcorresponds to the curve presented by the terminals of the ngers collectively.

Another object oftheinvention -is vto providef'r` a curvometer with which `curved surfaces are gauged by'fingers actuated `by the work-and restricted in these movements by cams serving as templets and further, thegprovision'of velectrical Y means which will visibly disclose Whether or 'noti-F530. the curve of the work ltoebegauged corresponds with that dened bythe terminals 'of the ngers.

YBroadly, the invention-seeks toprovide 'an apparatus of the character specifiedby which regu- W lar or irregular curves, `both 'concave and con-*3 Vex, may be gauged with greater `precision and accuracy than is jpossible by Vfixed Vgauges where accuracsnto a ,considerable extent, Vdepends .upon the .care and skill exercised .by .a workman inapplying them.

With the foregoingobjectsas paramount, the invention has .particular reference ...to ,certain features of accomplishment, to becomemanifest as the description proceeds, taken in 'connection with the accompanying drawings, wherein:

Figure 1 -is Va r`perspective Aview vof a vcurfvometer embodying lthe principles of .the presentl-invention.

vFigure 2 is a plan view, partly'broken away. Figure 3 isa .diagrammatic plan 'view of the cam .and -inger assembly and electrical `system 'associated therewith.

Figure l4 is 'agplot ofthe physical movements (CLS-"175) Figure. 5 is a detailview of ithefcentral Vorfnumber ione zcam.

Figure v`6 is a detail view of an intermediate or number two cam.

.Figure `7 is a'detail View of Vthe outside or ,numberthreejcam.

Figure '8 lis a 'detail view lof the central'cam' of the minus cam assembly.

Figure 9 isa detail viewof an intermediate or number twominus cam.

Figure 10 is a fragmentary-plan View "of one of the; minus system fingers,y and A.Figure 11is a sideelevation'al View thereof.

`Continuing with amore detailed description of the drawings, reference 7is primarily 'made to Figures 1 andZrshoWing vrespectively a perspective yand plan view 'ofthe `,machine and wherein "I0 designates a iframe supported upon legs lII `and upon which is Idisposed `a ferrousplat'e I2. Itfmay 'be mentioned 'at this point that the plate I2 `may be `constructed of plastic 'or other nonconducting material so long -as provision 'is made vfor completing a y circuit through theelectrical system for the purpose to be hereinafter de scribed.

In the approximate vcenter of fthe plate I2 there ris lprovided an opening I3 -to-accommodate the-cam assembly, tofbe :presently describedfand its lassoci-ated elements. On each side -of this opening "is situated a `pillow block I4, affording bearings furthe-shaft I5. The shaft -lcarries `a large-gear flS-on one end, a Aportion 4of -which :isreceived in -a slot I'I `inthe plate AI2 and whose `teethenmesh-those of 'asmall gear yI.8,-rnounted 5 oua.stub-shaft I9, whichoperatesin bearings 2D.

Mounted on Ythe stub shaft I9 is acalibrated dial 2|, .the numerical --graduations A22 on which may be .of .any lnature suited to rthe character ofthe work whose-curvesare to .be.gauged. In the present r-case, however, Iand .asan example of `the severaladapt'ations of A the ,machina the dial 2l has been marked with dioptric units according to the .metric system usedin Optometry in measuring the accommodation and refraction of the eye. While thedivision of the dial markings is arbitrary, it is preferred that the calibrations be so spaced that each mark will represent a .03D change and in order that the markings will be clearly legible, a magnifying glass 23 'is mounted in la uframe 24 overlying one point on the dial 2l and supported from the plate I2 on a leg VV25. A :hair line '26 on the `glass serves as a marker for the `graduations of the dial.

In Figures 4 lto '7, inclusive, is shown the 'plus system 'of camsan'd .Wh'ile specific dimensions are shown for a comprehensive understanding of one application of the invention, no limitation is intended. The cams are indicated on the drawings as 26, denoting the central or number one cam 21, denoting the intermidate or number two cam and 28, denoting the outside or number three cam. In these dimensions, angle arcs ABC- A'BC-A2B2C have a radius of 33.65 mm. Point D is the center line of shaft I5 and the external face of arcs AC-AC-A2C is the measuring plane for the plus system of cams.

The cams 26, 21, and 28 are arranged on the shaft I5 in the manner particularly shown in Figures 1 and 2, that is, with cam 26 or number one centrally disposed and fianked by cams 21 and 28, the cams 21 occupying intermediate positions between cam number one and the outside cams 28.

The cams are fixed on the shaft |5 so that the lines of each right angle design of the cams are respectively parallel and are limited to an arcuate movement of 90. Such movement of the cams is, of course, affected by moving the dial wheel 2| and the degree of rotation is determined by the ratio of the gears I6 and I8, which,

of course, depends upon the character of work to be measured and other factors including the size and spacing of the cams. Moreover, the cams are so disposed in relation to the dial that when they are positioned for a zero reading, the dial is at its zero mark.

Mounted for longitudinal sliding movement in guides 29 is a series of fingers 30, corresponding in number to the cams and which pass between and alongside the cams, above the surface of plate I2. Springs 3|, disposed underneath the fingers, are connected to points on the fingers spaced from the foremost guide 29 and to the guide itself and serve to resist inward thrust of the ngers. As a stop and means for predetermining the outward movement of each finger,

nuts 32 are threaded upon the rearmost thread- Y ed ends of the fingers and bear against'I the rearmost guide 29.

Attending each finger is a contact prong 33 which is made rigid with its finger by an insulator mounting 34, the latter being secured to the finger by a set screw 35. adaptation of the invention, the prongs 33 are spaced 12 mm. apart horizontally, each also be-"i ing spaced vertically in respect to the diiferent plane of action of the cams, that is to say; these nlanes of action remain in elevation 6 mm. apart. The tips of each prong 33 is spaced horizontally along the finger 30 with respect to the Zero# point on the cam faces. For example, the number two cams 21 have their zero reading points on their face 6 mm. horizontally behind the resnective reading point on the number one camY 2S and the number three cams 28 have their zero reading points 6 mm. horizontally behind the respective points on the number two cams 21. This horizontal spacing of the prongs 33 along the cams is arranged with the finger tips, 46 and 48 on a true parallel.

To each prong 33, there is connected a wiie 36 (Figure 3) which wires extend to signal means, which, in the present case, consist of incandescent lamps 31. The lamps 31 are, in turn,

connected to the supply wires 38 through wires 39 and a transformer 40. Ground is established from one leg of the transformer 4D, through 'wire 4| to the plate I2. As stated previously, should it be desired to construct the plate I2 of plastic'.

In the present or other non-conducting material, other suitable types of ground may be adapted.

In the grinding and polishing of eyeglass lenses, concave laps are used for producing a plus curve on a lens blank, while convex laps are employed where minus curves are desired. Figures 1 to '1 illustrate the adaptation of a system wherein plus curves are gauged while Figures 8 and 9 illustrate cams 43 and 44, used in the minus system. The internal face of arcs AC-AC-A2C is the measuring plane for the minus system of cams. Therefore, the plot of physical movement for plus-minus systems is the same. However, the number three minus cam 44 (Figure 9) are fastened to a collar 45 in a half circle, as shown, so that the maximum clearance can be obtained for the fingers or prongs, whose relationship with the minus cams is the same as in the plus system of cams.

In operation, if a plus lap having a '7.00 curve is to be identified or measured, the dial 2| is rotated until this unit is aligned with the hair line 26. The cams 26, 21, and 28 are thus brought into a corresponding position so that when the lap to be gauged is urged against the tips of the fingers 30, they will be longitudinally actuated against the tension of springs 3| toward the cams, bringing the prongs 33 into contact with the surfaces of the cams. Thus, the cams perform in the capacity of templets and their relative positions determine the curve defined by the ends of the fingers 30 which will be precisely '7.00, corresponding to the marking on the dial 2|. In the event the curve of the lap is exactly '1.00, then circuits will be completed through all of the lamps 31 by means of all of the contact prongs 33, wires 36 and cams, the latter through the ground wire 4|, plate |2 and shaft l5. On the other hand, a deeper curve on the lap would succeed in illuminating only the end lamps while a shallower curve will effect illumination of the central lamp through the central or number one cam.

In measuring a plus lap or curve, the tips of the ngers 30 are provided with balls 46 so that there will be no differential error caused by deviation of contact between the axes of the fingers and the surface to be guaged. For the same reason, the fingers 41 (Figures l0 and 11) are provided with flat tips 48. These latter ngers are designed to operate with the minus cam system and the function of this system is the same as in the plus system.

It is apparent from the foregoing that a high degree of accuracy and assurance thereof is obtainable through the use of the invention and where conventional metal gauges with fixed curves are employed to measure laps, not only do human errors reduce the possibility that a high degree of accuracy will be had in all cases, but also, Where precision is required within .03 of a diopter for some lenses, xed curve gauges frequently result in error by reason of worn or damaged surfaces, or by bits of foreign matter between the gauge and the work.

It is understood that irregular as well as regular curves can be as accurately gauged by utilizing the same principle as hereindescribed. To thus adapt the machine, a rearrangement of the cams to present the required surfaces to the iingers and prongs will, of course, be necessary.

Manifestly, the construction as shown and described is capable of some modification and such modication as may be construed to fall Within the scope and meaning of the appended claims is also considered to be within the spirit and intent of the invention.

What is claimed is:

1. An apparatus for gauging curved bodies including a plurality of predeterminately spaced cams lixed on a shaft and having substantially the same radius circle, a calibrated dial also lixed on said shaft, Whose rotation predetermines the angular positioning of said cams and whose calibrations correspond to and denote the pattern collectively produced thereby, a plurality of longitudinally movable lingers of equal length in operative relation to said cams, an electrically energizable prong carried by each of said lingers, said prongs being predeterminately spaced relative to each other and to the faces of respective cams whereby said lingers, When actuated, Will be limited in their movement by contact of said prongs with the faces of said cams to define at their ends a curve pattern corresponding to that collectively produced by said cams and visibly disclosed on said dial and signal means visibly revealing correlation between the curve of said pattern and that of a body.

2. An apparatus for gauging curved work surfaces, a cam assembly lixed on a shaft and a series of lingers corresponding in number to the cams, constrained to move longitudinally, means mounted on said lingers and engageable with the surfaces of said cams, which latter limits the displacement of said lingers and predetermines the curve pattern defined by the ends thereof in relation to the position of said cam assembly, a dial calibrated to denote the potential curve pattern of said cam assembly when a work surface is impressed on the ends of said ngers and electrical signal means common to each cam for revealing the curve differential between said work surface and that defined by the ends of said lingers.

3. In an apparatus for gauging curved Work, a cam assembly mounted for rotation in an arc of substantially 90, each cam of said assembly bearing the same radius circle and in which the lines of each right angle design are respectively parallel, means for actuating and visibly indicating the variations in pitch of said cam assembly to denote a distinctive curve, means actuated by the Work and controlled by the cams of said assembly for developing a curve pattern by known equations, means for setting said cam assembly preparatory to developing said curve and means common to each cam of the assembly for electrically indicating the curve differential between that of the work and the developed patterns.

4. A curvometer including an assembly of cams consisting of segments of a circle and aligned in equidistantly spaced relation on a shaft to serve as templates, means for moving said cams simultaneously in an arc to vary the potential curve pattern thereof and having means thereon to denote a selected curve, a series of longitudinally movable members against the ends of which a work piece is pressed, said members being under spring tension to constrain the same to become oriented to the curve of the work, electrically energizable means carried by each of said members and engageable with the faces of said cams to visibly indicate the same or a different curve from that of said work.

5. A curvometer including a series of relatively parallel and coextensive members constrained under spring tension to move longitudinally when a work piece is urged against the ends thereof, an assembly of templates movable arcuately on a common axis and collectively presenting a potential curve pattern through a predetermined range of equations, electrically energizable means carried by and insulated from said members and engageable with said templates individually when said members are actuated to transfer to said members the curve pattern presented by said templates and means connected electrically with said energizable means for visibly indicating the corresponding or curve differential between that of said Work and the pattern of said templates.

6. An apparatus as set forth in claim 5 in which the electrically energizable means are predeterminately spaced apart in two planes relative to each other and to the templates, the said spacing corresponding to the lix-ed prolile of the templates to insure predetermined orientation of the longitudinally movable members and means to eiect adjustment of the longitudinal displacement of said members.

ARTHUR J. WRIGHT.

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