US2332880A - Pantograph - Google Patents

Description

Oct. 26, 1943; H. H. WILDER rANToGRAPH Filed Feb. 22

Patented Oct. 26, 1943 1 l This inventionl relates to 'drawing4 instruments and l"particularly to pantographs oi 'theffchar-z acter for making copiesqfrom'master drawings orspictures. Bantographs 4are commonly-used `for .reproducing'drawingsro'r the likeuon enlarged or reduced scales. Much.; difficultyA 1 has..l been "encountered however; 'in .making` very `greatly-lenlarged .copies from originals;` as. `for example, .,in "increasing smallcopies to billboardsize; lWhenlrnakingA copies on a. gr eatly} enlarged scale with.pantographsunowavailable, the spread between the tracingqpencil v,and tracingrpoint. often becomes so great that a single operator is unable tomanipulateboth. It becomes neces- 23.32.8891 f l i1. insmeren t #Harvey vada Kaiisascia. MQ#

2, 19,43; sedative. 4762752", f

`2Il1or the like inay mannen @aerial giftig-.25. l. j

and. of the-"clamping member`I for retaining the pencil in adjustedcondition; `and Y 4Fig. 7 is a sectional `viewtaken on line VII-LVII' of Fig. 6. r

In;.the.-drawing, the numerals I6', 4I2 and I4, I 6' designate respective pairs of `parallel bars comprising the frame of the pantograph. rThesev bars .are `movablyconnected together by. rivets to .produce the usual parallelogram'l22.

Barszi and I2 are.relativelyjlong;bar;` being vpivotally secured atene` end.y to the upset boss4 24 of agbearing plate .26 Thefree end vOf, bar

sary therefore, that two operators coordinate their efforts, one guiding the tracing point, while the other guides the pencil. The results are often unsatisfactory, due to the difliculty on the part of the operators to maintain proper coordination of their movements. l

An important aim of the instant invention is manner to enable a single operator to make greatly enlarged copies from small` master drawings.

More particularlyit is the object of this invention to provide a pantograph with a holder for the master copy, adjacent the tracing point, and to embody means in theinstrument for maintaining the holder in its initially oriented position.

Other objects of the invention are to provide improved locking mechanism for holding the tracing point and tracing pencil in adjusted positions. l v

Further aims ofthe invention will become apparent during the course of the following specication, referring to the accompanying drawing wherein:

`the provision of a pantograph constructed in a y Fig. 1 is a plan view of a pantograph con- 1 in a depression 3i); Anopeningzinythe bar `I4 adjacent said cam faces is adapted to slidably receive a tracing pencil 34 and is aligned with similar openings 36 formed in the legsl 38 of a yoke 4i] astride the end of bar I4.

When yoke 4I) is moved from its dotted position l(Fig. 6), to the full line position, a cross pin 42 provided therein rides over cam face 28 to impart a slight shearing action on the trac- Bars I0 and I4 are relativelyulong, bar I0 being of intersection by a, removable pivot pin 58.

` Series of spaced apertures `6I] and 62 in bars I2 and I6 respectively, provide for adjusting the pantograph to obtain the desired ratio of enlargement.`

In order to support a master copy 64 on the pantograph adjacent tracing point 46, an arm `66 is pivotally connected intermediate its ends to the free end of barI2 as at I'l.` VRiveted or otherwise secured to one end of arm 66 is a holder 68, preferably provided with rebent flanges I0 along three of its edges for retaining the master copy in place.

It is evident that holder 68 should maintain a definite relation to the surface whereon the copy is made irrespective of the movements of the pantograph. This is accomplished by providing bars 'I2 and 14 which are interconnected to each other and to bar I0 by a plate 16. Bar I2 is movably joined to arm 66 by a rivet 18 and bar g'ld, in parallel relation with bar l0, is pivoted on an upset boss 80 of bearing plate 26.

The operation of the pantograph will be: clear from the foregoing. A single operator can move the tracing point along the outlines of the vmaster copy and simultaneously guide the tracing penciLsince the distance between the pencil and tracing point is never exceedingly great.

It will be apparent from Fig. 1 that the traced drawing is `as many times larger than themaster copy as thegdistance ,from pointsZQ to .36 `is 'greater than the distance from points( lltY to (il.

The scale of enlargement may be varied in the usual manner, i. e., by engaging the pin 5,8vwith other of the openings 60 and 62 in bars I2 and vlli respectively. Pin 58 preferably has V-s;crew

threaded engagement with openings [62 of bar IB.

the point on said bar comprising a exible blade "fned to said bar and having a free end portion From the foregoing description, it will be see'n' i that the objects of this invention have beeni accomplished and since it is possible that various modicationsr might, be gmade; without departing from the spirit ofzthisinventionf, fit isA desiredto be limited fonly bythe scope of the appended claims. c

Having thus described the invention, what is claimed as 'newand desiredvto be: secured by Letters Patent is: i y

Y 1.x'Inra pantograph,` tti-pluralityl of lbars ably connected'together; a tracing point on one of the bars; a holder pivotally mounted on said pantograph-for supporting amaster copyi'adjacent said tracing point; and means operably' connecting said holderf with the pantograph `for maintaining the-holder' in its initially oriented position during the tracin'grprocess.

il i-noiset relation with the said bar, said bar and free-endv portion having aligned openings for slid'ably receiving the tracing point; and a spring positioned .between the free end portion and bar i and. surrounding the tracing point for urging said `freev end portion of the blade into binding Veng agementl with-said vpoint for holding the point inadjusted position..;.j. f Y Y l t s' 4.'. In a pantograplnga.pluralityofL bars mov.-v ably connected together; a tracing pencil on one of the bars; and means for holding the pencil in adjusted positionrelative to the'bar comprising a yoke'havingspi'icedf legsj :for receiving an end of'sa'i'd bar therebetween, said bar and legs hav. ing" aligned openings: for slidablyr, receiving the tracing pencil, said end ofathe'b'ar fharvingacarrr faceia'nd thei legs of said yokehavingacross pin therethrough iforiridingover the cam face to lock the penciliin l'adjusted` position.

vvILDER. l

Images