US2496781A - Pantograph - Google Patents

Description

Feb. 7, 1950 R. M. ElCHMANN PANTOGRAPH 2 Sheets-Sheet 1 Filed Feb. 15, 1946 ATTORNEY Feb. 7, 1956 EICHMANN 2,496,781

PANTOGRAPH Filed Feb. 15, 1946 2 Sheets-Sheet 2 RICHARD 1V1v E/CHMANN ORNEY Patented Feb. 7, 1950 UNITED R-ATENT OFFICE "7 'Cla'ims.

This invention .is a duplex pantograph comprising two 1 simple .pantographsronnected to one another so that the manipulation (none-serves to impart movement to the other. .These two Jpant-ographs are so interconnected with :respect -to one another as vtopprod uce an extremelyfine fixed anchorage with respect to the vboard :and

to eachother, while the intermediate el bows ef the .two .pantographs are pivotally cconnectedito -.one another so "that both .pantographs .havepin efiect, a -1c0mm0n elbow ,pivot. :Flor theapurpose of concrete definition, one of the .pantographs -wil1 be hereinafter arbitrarily termed the i'pri- .mary ,pantograph, while the -other will met-reiierred to as the secondary.pantograph.

When primary and secondaryapantographs are connected together loy a :commonelhowpivohand with their respectiverfulcrumslanchored.in-nxed position to a kbar and vilooard, .as stated, the :move- .ment of a tracer, supported-rat itheufreeendwoi the primary zpantograp-h, will produce a lesser degree of movement ofthe elbow 30f that'iprimary pantograph with corresponding movementv-ofvthe elbow of the secondary ;.-|pantogra ph. But this corresponding lesser movement .or the elbow-of the-secondary.pantograph willreffect an increase in amplitude of movement of the marker carried at the :free end .of-the latter. --"Jl-'hus,wvhenthe duplex .pantogra-ph of this invention-is employed "for enlarging purposes, the ,primary-pantograph will have thefunction 10f decreasing the ampli- .tude of movement, while therzsecondary pantographwill have the function-of translating this decreased .movementinto increased amplitude of the marker whihlit carries. These two functi'ons 'arercombined to operatelconjointly, to ,produce a "reproduction an the same size .as the *images, or enlargedor'd'ecreasedreproduction as may be desired.

The-advantage ofthi's' arran'gement is'that'very fine reproduction is accomplished w'ithinlarge dimensions and 'throughan extremely wide' range of ratios" between the-original image and the rezproduction or copymuch more so than :has heretofore been possible-withaanypantographof production may be obtained :by this-duplexstruc- .ture. 'This is impossible of accomplishment .with asim'plepantograph.

.The several arms oflooth .pantographs carry graduated scales .withappropriate associated-per- -iorations, whereby each-of said ,rpantographs-may zbe .set to produce the desired ratio .inreproduc- 'tion as will he hereinafter more fully .set forth.

Features of the invention, othert'han'thoseadvented to, will be apparent from .thehereinafter detailed description and appended claims, when rreadlin conjunction with the accompanying draw- .mgs.

I-he accompanying drawings illustrate one .practical embodiment of the invention, .lout the construction therein shown is to be understood as illustrative, only, and not as defining thelimits oftheinvention. I

Figure 1 is ape'rspecti-ve viewshowing aduplex 20 gpantograph embodying the present'invention with the several parts thereof set or adjusted for e'qualityin reproduction.

Figure 2 is a perspective view showing the-tulcrum connections for the secondary ,pantograph, certain ,parts "thereoifloe ing dismantled in the "interest of clearness.

"Figure3'is a'view similar to Figure Zlout showing the fulcrum mounting for the rimar panto- Fgrap'h.

Figure '4 isan'end' view of means foriclampin'g ;a,supnortingbar toza drawing b oard.

Figure 5is a section on the;linei5 5'of Figured.

In the accompanying "drawings, the primary pantogra'ph'is generally designated I0. 'It em- Silbodies arms l1, l2, I3 and Hi. 'The arms H and f2 cross "one another and are secured together flay a=removaple pin l whi'le the arms rs and P4 similarly cross one another and are secured to- 'gether :loy-a removable pin 16. The-arms M and 40 F4 are shown as slotted 1 orsubstantially their 'full .Iengths f and "the arms I12 r-and 'l-3 pass through the :slots, and the pins 15 and 16 extend through the entire depth of-thearms II and Mw'to facilitate accurate adjustment and smooth operation and :to eliminate .-l0st motion and twisting strains.

Lhear-Ins :ll and I4 aresecured to one-another by a permanent pivot l1, while the arms 12 and -13 are pivoted to one another at theelbow of "this pantograph byapin general-lydesignatedlhy the reference character f8.

All of the arms of the vprimary pantograph "carry graduated scales with associated perforations'lfl. These scales will he hereinafter more "fully described, 'ib-llt :s-ufiice it here to point out which lam-aware. Eurthermoreequdlitybf rel5 ithatthepins l5 and f6 may'ibeshifted-alongthe 'to show their individual structures.

mounted on a rigid bar 38.

scales of the several arms to cooperate with different perforations H! in order to vary ratios of enlargement or reduction as the case may be.

In the form of the invention shown, the free end 29 of the primary pantograph carries a 5 tracer 2|, While the other end of said pantograph is fulcrumed on a pin 22 which constitutes the fixed fulcrum for any particular adjustment.

The secondary pantograph comprises arms 23, 24, and 26. The arms 23 and 24 cross one another and are perforated to be connected by a removable pin 21, while the arms 25 and 26 n cross one another and are perforated to :be connected by a removable pin 28. The arms 23 and 25 are permanently pivoted to one another on a 15 pin 29, while the free end of the secondary pantograph carries a marker 30. The free end of the arm 23 is pivotally supported on a pin 3| which constitutes a fixed fulcrum for the secondary pantograph when set up in any particular adjustment. The details of the fulcrum mountings of :both the primary and secondary pantographs are shown best in Figures 2 and 3 of the drawings wherein the parts are dismantled sufficiently Thus by reference to Figure 2, it will be noted that the free end of the arm 23 carries a bracket 32 and this bracket, as well as the arm 23, is provided with alined or coaxial perforations or bearings 33 and 34, axially spaced apart. The $0 fulcrum pin 3| of the secondary pantograph is formed as an upper reduced end of a stud 35 which has a cylindrical portion equal in height to the spacing between the bearings 33 and 34. The pin 3| extends into the bearing 33 and, from the cylindrical part 35, a second coaxial pin 36 extends downwardly through the bearing 34 and is adapted to be received within a block 31 forming part of a carrier adapted to be adjustably I find it desirable it to make this bar of substantially keystone shape with the wider portion at the top. r The block 31 is substantially L-shaped so as to bear against one side and the top surface of said bar, while the plate 39 bears against the 5 opposite side of the bar and is attached to the block 31 by means of a thumb screw 40. This thumb screw wo'rks idly through the plate 39,

passes through a hole 4| in the pin 36 and threads,.,..

into a tapped hole in the block 31. Thus this "5 thumb screw 40 serves not only to secure the stud 'to the block 31, but also serves to tightly clamp the carrier to the bar in any desired position of adjustment longitudinally of the later. Notwithstanding this tight clamping engagement, how-"5 ever, the arm 23 of the secondary pantograph is free to oscillate about the axis of the stud, which provides a relatively deep bearing for this articulatory movement. This deep bearing serves tor.- support the arm 23 throughout its entire length, 60

as well as the attached end of the arm 25, so

that the outer ends of these arms will not contract with the board B and will be properly supported even though these ends extend beyond the confines of the drafting board B on which 5 the device is mounted.

The mounting for the fulcrum pin 22 of the primary pantograph is shown in Figure 3. It is p the same in all respects to the structure shown in Figure 2 save only that the cylindrical part 35 is of less axial length and the pin 22 is longer than the pin 3 I. These differences in dimensions provide for proper relation between the two pantographs so that the cooperating arms of both of them will lie in contiguous, substantially parallel planes.

The supporting bar 38, by which the fulcrums of the two pantographs are supported, is adapted to be rigidly secured to the drafting board B or other table on which the reproduction is adapted to be carried out. The rigid attachment of this bar to such a board or table may be accomplished in various. ways, but a very satisfactory means is fihiiw t Figllljs 4 and', 5, asembodying a C-clamp 42 of special construction. This C-clamp is shaped to embrace the margin of the board B and to be firmly secured thereto by two thumb screws 43. These collectively serve to form a three point support between the clamp and the board B and afi'ix said clamp to the board with great rigidity. The head of the c-clamp is provided with a straight-through passage 44 through which the bar 38 is adapted to loosely extend, but said bar may be anchored in any desired position by means of a set screw 45 which is threaded into the head of the clamp and projects into the passage 44. The purpose of clearance between the bar 38 and the passage 44 is to permit of longitudinal adjustment of the bar within said passage, so as to locate the fulcrums and hence both pantographs in optimum positions on the board with respect to the work to be done. For certain reproduction the setting of the bar shown in Figure 1 will be highly efficient. In some other cases the bar 38 might be well adjusted to the right or left with respect to the clamp 42. In Figure 1 the fulcrums of both pantographs are positioned on opposite sides of the clamp though for some reproductions, both fulcrums may be positioned on the same side of the clamp. This adjustment of fulcrums can be readily obtained by loosening the clamping screws 40 to release the carriers 31, which may then be shifted or adjusted as desired and thereupon locked in place by again tightening the clamping screws 40.

Reference has hereinbefore been made to the 'graduation or indexing of the several arms of the two pantographs, with corresponding perforations to permit of adjustment for reproduction at different ratios. In the illustrative showing of the drawings, the arms of the primary pantograph are indexed with graduations progressing in increments of /8" from A; to 2, while the arms of the secondary pantograph carry main index points I, 2 and 4. If the arms of the secondary pantograph are adjusted so that the pivot pins 21 and 28 pass through holes corresponding to the graduations indicated I, and the pivot pins l5 and I 6 of the primary pantograph are likewise passed through holes correspondingly indicated, the image will be of the same size, i. e., inch for inch with no reduction or enlargement. Now if the pins 21 and 28 are left in the perforations l of the arms of the secondary pantograph, it is possible, by varying the adjustment of the primary pantograph, to change the enlargement or reduction ratio from to 2, although it would be necessary in doing this to reset the fulcrums 22 and 3| on the supporting bar 38 in order tomaintain the most efiicient relation between the image and the original.

By wayof further example, if the secondary pantograph is adjusted so that the pins 21 and 28 pass through the points indicated 2, then by setting the primary pantograph at points i or 2, the enlargement can be made twice to four times the size. Similarly by setting at points 4 in the secondarypantograph, it is possible to obtain enlargements of from four to eight times by aaecwsi ichanging the adjustment of"theiprimary"pantograph.

It will be 'noted from Figure "1, that thearm's :of the secondary pantograph contain relatively ffl negraduations .or short scale perforations adjacent the graduations I. These are to permit of slight variationsin ratio which individual users may desire. These small graduation s'calesmay, if desired, also be associated with each "of the graduationsiandflon all ofthe arms of the secjondary pantograph if desired and they make it possible to work through blind'points between'the flarge graduations with small increments "of change in ratio.

The gra-duations or scales to which'I have'referred and which have been shown in thedr'awings have been found to be highly satisfactory "for most purposes,'but I wish it understood that they may be 'variedwith'outdeparting from this invention.

' It'will be apparent from the foregoing detailed description that the duplex pantograph of this invention embodies, generally speaking, two pantographs connected to one anotherat their elbows with their fulcrum's relatively fixed for any particular ratio adjustment upon a rigid bar which is, in turn, rigidly mounted on a firm support on which the'reproduction is carried out. This reproduction may manifestly be in the nature of either enlargement or reduction, depending upon which of the parts 2! and 3| is the tracer and which the marker. When reference is made to-the marker, it =will'be understood that this may be a pencil-or pen or an engraving or any other typeof tool by means of which it is desired that the reproduction be made. In any *event, the two pantographs are permanently attachcd to one another and-constitute, in effect, a unitary working device, all parts of which are interlocked, to produce a unitary result. The long bearings to which I have referred serve to effectually support the device for efficient operation, so that the arms will not drag upon the drawing board nor will the fact that the arms or joints thereof may project beyond the board, interfere with the proper functionin of the device. These long bearings also minimize friction, lost motion and wear which would result in imperfect or faulty reproduction.

In the accompanying drawings and in the preferred form of this invention, the two pantographs are interconnected with one another at the pin is which constitutes the common pivot for one elbow of each pantograph. Each of the pantographs which enters into this construction is of the lazy tongs type in that each comprises two pairs of crossed arms pivoted to one another at their point of crossing and with each pair of crossed arms pivoted to one another to form the elbows of the particular pantograph formed by each two crossed pair of arms. elbows of each pantograph is, as stated, secured to the corresponding elbow of the other pantograph, so that the primary and secondary pantographs, as I prefer to call them, have a common elbow pivot 28, Each of these pivots has a fulcrum pivot (22 and 3i) at the free end of one of the arms, while the other end of said arms is terminally connected (ll and 29) to another arm, the other end of which carries a stylus (2| and 30), all as clearly shown in the drawings.

The invention as stated is primarly directed to a duplex pantograph. There are, however, numerous features embodied in the present structure which will be highly utilitarian in a single One of these '6 for slniplepantograph. For example, if the "prifmary and secondarypantographs are separated at thep'ivot "1'8 and one'rem'ove'd, so :that' the other might b'e'used'as'a simple pantograph, very appreciable advantage would be had in the use of the "el'amp42 tandbar 38 as amounting for the remaining pantograph. It would provide a very efficient supportfor -the1f1i1cr1im of this pantograph 'andwould" permit adjustment of the same 'laterallyof the board B.

f Furthermore, in many cases a distinct advantagewould result in'the use of a simple pantographby mounting its fulcrum directly on is. lampsudh as' the clamp '42, so as to be rigid therewithand to provide for a rigid mounting of 'suchfulcrum on th'eboardi in a'manner topermit the clamp to be adjusted'longitudinally of the edge, of the bo'ard and clamped rigidly in any position'desired thereon.

Another feature of the invention useful in simple pantographsis [the employment of the slotted arm construction shown in the primary ,pantogra'ph wherein the arms [2 and I3 ,pass fthrough slots'in the arms I] and.

]For the foregoing reasons the invention .=is to be. understood as including theseffeatures, as .wen "asthe broad, concept .of the duplex pantograph mounted .on theboard. inthe mannerlhereinbefore described. I l

The foregoing detailed description sets .forth the invention in its preferred .practical Tform, but the'invention is to Ibe'understood as fully commensurate with the appended claims.

Having thus fully described the invention, what .I claim as new and desire to secureIby Letters Patent is:

"1. "An assembly of'the character describedcoin- .prising: .a clamp .adapted to rigidly .engage a ,drawing board or the like and provided with-a passage, La. rigidfbar adjustable longitudinally ,through said ,pas'sa e while the clamp .is in rigid engagement with said board, a thumb screw for securing the bar in adjusted position, a pair of carriers mounted on the bar for adjustment longitudinally of the bar and having means for looking them in selected positions thereon, a fulcrum on each carrier, and a pantograph secured to each fulcrum, each pantograph having an elbow and said pantographs being connected to one another by one common elbow pivot for both of them.

2. A duplex pantograph comprising: two lazy tongs pantographs each having two pairs of crossed arms pivoted to one another at their points of crossing with the arms of both pairs of each pantograph hinged together at their ends to form the elbows of that pantograph, a common pivot securing together one elbow of one of said pantographs to the corresponding elbow of the other pantograph, a rigid fulcrum bar, and a fulcrum pivot securing the free end of one arm of each of said pantographs to the fulcrum bar in spaced relation to the corresponding fulcrum pivot of the other pantograph.

3. A duplex pantograph comprising: two lazy tongs pantographs each having two two pairs of crossed arms pivoted to one another at their points of crossing with the arms of both pairs of each pantograph hinged together at their ends to form the elbows of that pantograph, a common pivot securing together one elbow of one of said pantographs to the corresponding elbow of the other pantograph, a rigid fulcrum bar, and a fulcrum pivot securing the free end of one arm of each of said pantographs to the fulcrum bar;

in spaced relation to the corresponding fulcrum pivot of the other pantograph, said fulcrum pivots being adjustable longitudinally of said bar to vary the distance between them at the will of the operator.

4. A duplex pantograph comprising: a primary four arm lazy tongs pantograph with its fulcrum at the free end of one arm, and its stylus at the free end of the arm which is terminally jointed thereto and having an elbow at the terminal joint of the other two arms, a secondary four arm lazy tongs pantograph with its fulcrum at the free end of one arm and its stylus at the free end of the arm which is terminally jointed thereto and having an elbow at the terminal joint of the other two arms, a common pivot connecting 'said elbows of both the primary and secondary pantographs, and a rigid bar carrying the fulcrums of both of said pantographs in spaced relation to one another.

5. A duplex pantograph comprising: a primary four arm lazy tongs pantograph with its fulcrum at the free end of one arm, and its stylus at the free end of the arm which is terminally jointed thereto and having an elbow at the terminal joint of the other two arms, a secondary four arm lazy tongs pantograph with its fulcrum at the free end of one arm and its stylus at the free four arm lazy tongs pantograph with its fulcrum at the free end of one arm, and its stylus at the free end of the arm which is terminally jointed thereto and having an elbow at the terminal joint of the other two arms, a secondary four arm lazy tongs pantograph with its fulcrum at the free end of one arm and its stylus at the free end of the arm which is terminally jointed thereto and having an elbow at the terminal joint of the other two arms, a common pivot connecting said elbows of both the primary and secondary pantographs, a rigid bar carrying the fulcrums of both of said pantographs in-spaced relation to one another, said fulcrums being adjustable longitudinally of said rigid bar to vary the distance between them at the will of the operator, and a clamp longitudinally adjustable with respect to said bar for rigidly clamping said bar to a table or other support.

7. In an assembly of the character described, a clamp adapted to be rigidly clamped to a drawing board, said clamp being provided therein with an opening, a rigid bar extending through said opening and longitudinally adjustable therein, a set screw for securing the bar rigidly to the clamp, and a pantograph with its fulcrum rigidly supported on the bar.

RICHARD M. EICHMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 310,186 Diamond Jan. 6, 1885 350,027 Wang Sept. 28, 1886 503,934 Braastad Aug. 22, 1893 790,172 Benton May 16, 1905 1,383,914 Emmerling July 5, 1921 FOREIGN PATENTS Number Country Date 233,689 Great Britain July 27, 1926

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