US2612694A - Drafting machine - Google Patents

Description

F. E. VAUGHAN DRAFTING MACHINE Oct. 7, 1952 3 Sheets-Sheet 1 Filed July 11, 1945 F. E. VAUGHAN DRAFTING MACHINE Oct. 7, 1952 3 Sheets-Sheet 5 Filed July 11, 1945 Ir 7//////////! rllllllllllll .7

3nventor:

FQA/vc/S E l Aua/m/v a dm m m M Gttorneg Patented Oct. 7, 1952 UNITED. STATES PATENT OFFICE 1 I; Q'2, 1 2 ,s94 I I. I b

DRAFTING MACHINE Francis E. Vaughan; PasadenapCalii'. Application JulyQl l, 1945, Serial No. 604,494

member, a second arm pivoted at one end to the moving end of the first arm, and a drafting head carried at the" free end of the second arm and movable over the drawing board. The drafting head includes a protractor and a protractor arm' 4 provided with a Vernier or witness point and with means for holding one or more rulers or straight drafting machine Y warms. (CI. 33-79) V 2 Another object of my invention is to provide a worm and gear mechanism operating between two members of a drafting machine in which the gear is mounted on a shaft carrying one member and the worm is mounted so as to move with the other memben-saidworm beingmounted'.

1 on a support-which is movable with respect to edges which can be rotated about the protractorf As the drafting head is'moved over the drawing board, orientation of the protractor is held dong.

stant either by some combination of pulleys and bands or bysome combination of parallel arms.

The protractor-armis rotatable with respect to the protractor and is adapted to be held firmlyin any desired azimuth.

An object of my invention is to provide a'micrometric control means in a drafting machine wherebyone member in said machine can be moved slowly and under firm control through either large or small angles with respect to another member in said machine.

Another object of my invention is to provide the drafting head of a machine of the character described above with a micrometric protractor arm'control, that is to say, micrometric control means is provided whereby the protractor'arm and gearmechanism operating between a pro- I tractorarm and a protractor.

Another object of my invention is to provide a means for readily engaging or disengaging the micrometric control means so that the member or protractor arm in said machine can be ro-' tated under micrometric' control or freely rotated as may be desired.

Another object of my invention is to provide the micrometric control means with over-center means, that isjmeans whereby the worm is urged into engagement with the gear when the overcenter means is in one position so as to eliminate lost motion,, and to firmly urge theworm away from the gear when the over-center means is in the other position in order to eliminate th e likelihood of accidental-engagement.

1 3 engagement. 1

the gear; so that the worm can be movedrinto engagement with the gear or away fromtheggear as desired. Another .object of my invention is to provide a drafting machine with a. micrometric control, ,means, said ,micrometric control means being belowith'e handle for ease of positioned just operation. c 2

Another object of my invention is to provide .a.

drafting .machine in which a gear is mounted above the pulley and concentric therewith, and

in which movable means are provided'for engag ing the'gear; 1

Another object ofmy invention is to provide a' drafting machine in which a gear is mounted above the pulley andin which a worm screw. is

mounted on a support carried by ashaft concentric with the pulley, and is adapted to engage the gear "so that the members which are connected to the gear and worm screw; respectively, can be rotated either freely or under firm control. Another object of my invention is to' provide means for readily engaging and disengaging said worm screw from said gear.

Another object of my invention is td'provid'e resilient means for urging the worm'screw against the gear when the worm screw and gear are in Another object of my invention is a-drafting machine in which the worm screw is mounted on a movable support and in' such a manner that when the movable support is" moved to one position,"the worm screw will be in engage ment with the gear, and that when the movable" support is moved to another-position, the worm vscrew will be clear of the gear; I

My invention has many other objects advan tages, and features, some of'which, with'the fo're -f going, will be apparent from the following description and the accompanying drawings which are now considered to be preferred'einbodiments' of the invention. It should-be understood, how ever, that these particular em'bodiments-of the of forms.

to; provide Figure 5 is a plan view showing details of the subplate carrying the worm, and the method by which it is mounted upon the handle plate- 1;.

Figure 6 shows a modification of.,my invention in which the gear is mounted on the inner shaft with the handle, and the wormscrew ismounted on the outer shaft, the view corresponding to Figure 4 of the structure shown in Figures 1'-5 inclusive.

Figure 2'7 isanother View of the modification of my-dnventiom-shown in Figure 6, the view corresponding to Figure: 3 of the structure shown in Fi'gures1 5inclusivec Any conventional means can be used to hold.

with respect to the protractor 28. As an instance of this arrangement, disposed in the hollow shaft 20 is a smaller shaft 32, at the lower end of which are a flange 33 and a cross pin 34. The protractor arm 36 is designed to rotate with the shaft 32 by being pressed firmly down against the flange 33 in such a manner that the cross pin 34 is pressed into a slot 35 in the protractor arm, The upper end of the shaft32 isthreaded anda nut 35, screwed lightly downagainst the upper end of the hollow'shaft 2ll,"holds the protractor arm 38 up against the protractor 28,

' but permits said protractor arm to be rotated with respect to said protractor 28 and the lock plate 23 to which said protractor may be locked.

Abovethenut 36 is the handle plate 37 having a slot:33 similar-to the slot in the base plate, said slot 38 being provided to receive a cross pin 39 through the shaft 32. A nut 4!] acts as a lock to hold the nut 36. and the handle plate 31 firmly 1113011713116 shaft-32.; A handle -4l-.is

fastened. to the -upper,side of- -the handle plate fl byimeans of screws 42, by means of which theiprotractor arm 30 is. adapted to be rotated;

thewprotracto'r in constantorientation as it is moved over the board; In the drawings; I have shown a bandand pulley arrangementfor-.illustrative purposes only.

Referring to the form of my invention-"shown imFigures-i to 5g'thenumeral ll indicates any conventional clamp for-holdingthe draftinglmachine'to adrawing.-::board l2. The. clamp-Ii carries. a pivot shaft rising perpendicularly to V the board, to which is rigidly afiixed a single groovepulley (not'shown) whichis-engaged by a band :13. An arm .I 4-'is pivoted. to the shaft by. a suspension head 15in such amanner that it cantbe ro'tate'd about said shaft. .At the other end of the arm [4 is a two groove pulley-(not shown): which is mountedon the axis of articulation%:at;l6 'between'tthe'arms I4 and: IT.

a band vI 8 engages the: other groove: v

shown in:Figure 3, the. other end of the: arm

The band-"13 zengages one groove of this 'pulley and I'l is-connecte'd-"to azpulley housing .19; in which"v ismounteda hollow shaft 20 by means of ball hearing; I .Thehollow-shaft -2 0. is provided with ar-flange 22 at its. lower end andthreadsi'at its upper end; Also mounted on-said-.hol1ow shaft- 20 is a lock plate 23 anda pulley-24 which, -togather with the above-mentioned ball bearing 2|, are held in 'positionby-means of; nut; 25;:

265,-. The-band l8 engages the pulley 24; A gear The,- lock .plate123 and theqpulleyrlli are-adapted to be held together as a unit by means fofscrews- 25. Concentricwith the hollowshaft 20' istha;

protractor --2 8. which can be engagedto: rotate with the shaft 52 0' by-;alock lever device 29' which looks the protractor 28 to the lock plate '23; Des

tails -,of the lockleverdevice 29 "are; shown in."

Figure 4. From theforegQing :it :isclear that the gear. 2-! isl-flxed tothe shaft 20: moreover, the

tractor, serving as a guard and bearing a wit,-

ness po1nt to indicate :the angular iposition-ofr the @protractorarm relative; .to the protractor-.1

Mounted upon the protractor-arm 30 isthe scale;

I he protractor arm 30 is adapted to be rotated;

Micrometric control means is provided where by the protractor arm 30 can be movedslowlyy and under firm control-with respect-to the pro;

tractor 28 through either large or small angles, 4 together;with meansfor readily engaging or disengaging the micrometric control means so that, the protractor arm 30 can be rotated under; micrometric control or freely rotated-as may be desired. As an instance of; this arrangement as shown in Figures 2' and 3 and in somewhatgreat :er detail in Figure 5,a subplate 43 is fastened-to,- the underside of the-handle plate 31- This-sub plate; is designed-to-rotate through a smallarc; about a flanged bushing 44, :Whichisheld firmly against the handleplate 31 by means/of the screw 45. -A spring washer 46 between the flange of the bushing 44 and the subplate 43holds the latteragainst thehandle plate 31 and eliminates. vertical play. A flanged stop bushing. 41 passes through a slot 48 in the subplate 43 and isheld firmly against thehandle plate 3'! by means ofthe stop bushing screw 49.

handle plate 3?.

Depending from the-subplate 43 are twolugs 50-and5l provided with-holes52 and 53, through which passes a shaft upon which 'is-fixed;a .worm 55 between thelugs 50Hand 5|. A spring washer 56 on the shaft 54, and interposed between-one end of -theaworm55.and thelug50, isprovided to "eliminate end play of the worm between thelugs; To-the outerzendof the shaft .54 is fixed a knurled thumbpiece -51, bysmeans of-which the shaft 54 and the-worm 55 canbe rotated, The thumbpiece 5'! can also be: used to rotate the subplate 43 through its small are about the -bushing 44; .thatis to say, it can be-"usedr, to engage. and disengage the worm 55,-and thegear 21. One limit of the arc, as determined by the slot-48, is such that the worm55rwi1l; clear the gear 2'! when the subplate is pressed-as far as possible outward andaway from the center of, the handle plate .31. The other-limitof the arcas. determined by the slot .48, permits the worm 55-to engage firmly the gear 21 whenthe sub-i plate is. moved as far aspossible toward the. center of the handle -plate 31; indeed; the:-= slo;t permits slightly greater motionr than the ge,a r;

The purpose of this. arrangement -is to-limit the are through which-the subplate 43 can be rotated about the bushing 44; moreover, the flange of the bushing... 41 tends to'hold the subplate 43 close to the.

permits, so that firm engagement is insured even after some wear has developed between the worm 55 and the gear 21.

An angular projection 58, with asomewhat rounded point, is provided at the end of subplate 43 remote from bushing 44. vA spring 59 is provided to hold the subplate .43 in one or the other of its extreme positions. One end of the spring '59 is fastened to the handle plate 31 by means of the screws 60 and 6!. The free end of the spring 59 is provided with an angular projection 62, with a somewhat rounded point, similar to the projection 58 on the subplate 43,

directly opposite the mid-position of the projection 58 as the subplate moves'through its restricted are; that is to say, it lies opposite the position midway between the two extreme positions of the projection 58' as the subplate 43 is.

moved through its limitedarc about the bushing 44. It should be noted particularly that on either side of the mid-position of the subplate 43' the force components of the spring 59; :trans-' mitted by the inclined surfaces of the projections 58 and 62 along the path of the point of the projection 58, are in opposite directions. It is clear that this arrangement provides an overcenter mechanism whereby on one side of the center the subplate 43 is pressed toward one limit of its restricted arc and on the other side of the center said subplate is pressed toward the other 'limit of the arc; that is to say, it

By makingthe :gear 2'! with a 'specialnumb'e'r of teeth the wormand gear arrangement shown becomes. an effective. indexing mechanism .for quickly setting'oif some of the most frequently. used angles. For example, providing the gear- 21 with 72 teeth affords certain advantages- With the worm 55 and agear 27 having 72 teeth, in-engagement with each other, rotate the thumb piece 51 until the protractor reading is zero or any multiple of 5degrees. Now press the thumb piece 51 so as'to disengage the worm 55 and. the gear 21; rotate the protractor arm to ap-. proximately the desired angle, 30 degrees for,

example; firmly press the1thumb piece 51' so as to engagethe worm 55 and the gear 21. The protractor reading will now be 30 degrees. a similar manner, the protractor arm canbe brought-readily to any angularposition repre-'.

sentedby a multiple of 5 degrees. Obviously,

the gear could be made with some other number i of teeth to provide a different selection of angles.

In the modification'of my inventionishown in Figuresfi and 7, the gear is mounted on the inner provides means for pressing the worm in engagement with the gear 21 on the one hand, and for holding it clear of the gear 21 on the other hand.

In actual use the drafting machine is affixed to the board I2 by means of the anchor H, as in Figure l, the drafting head being adapted to be'moved over the board while the orientation of the protractor 28 is maintained through the pulley and band arrangement. The orientation of the protractor arm 30 with respect to the protractor 28 is maintained through the worm 55 and gear 21 mechanism. During muchof the ordinary routine work, the orientation of the protractor arm 30 is such that the ruler thereon is parallel to two sides of the drawing board and to some of the primary lines of the drawing itself. At the same time the protractor reading is zero. As it becomes desirable to draw lines in the directions thus indicated at various positions on the board, the drafting head can be moved across the board by taking hold of the handle 4| or of the-ruler 3| and pushing it into position. During this procedure it is usually desirable to have the worm 55 and the gear 21 28, the rotation being accomplished either by i means of the handle 4| or by taking hold of the scale 31. When the protractor arm has been rotated to approximately the desired position, the thumb piece 5'! is pressed with the thumb of the left hand so as to engage the worm V 55 with the gear 21. The protractor arm 30 shaft 32 and is connected to the protractor arm 30 and the .wormscrew is mounted on the outer shaft 20 and connected to the protractor 28.

The worm screw is so mounted on the outer hollow shaft 20 that it may be readily engaged or disengaged from thegear so that the protractor arm 30 can berotated under micrometric control or freely rotated. as may be desired.

As an instance of this arrangement, a gear.

65, a spacer 66, and a handle plate 61, are fastened together by screws-68 so as to comprise a mechanical unit. This unit is mounted on the. shaft 32 by means of nuts 69 and 10, and the A worm screw 12 is mounted on a sub-. r plate 13 carried on a support 14 which is .mounted on the hollow shaft 2!] by means'of nut 25.. The subplate 13 may be. movably: mounted' upon the support 14 in precisely the same manner that the subplate143 is Imovably mountedupon'the handle plate 31.

vention shown in Figures 1 to 5.

Obviously the operationof this form'of my invention is essentially the same as the operation of the form of my invention shown in'Figures l to Band will therefore not be repeated herein.

From the foregoing description take 'in connection with the accompanying drawings, the

uses, advantages, and operation of the drafting machine of my invention will be readily understood 'by those skilled in the art to which the invention appertains. While I have'described the principle of operation together with the forms of my invention which I now consider to be the best embodiments thereof, I desire to have it understood that the machine shown is merely A illustrative and that the inventionis not to be limited to the dtails' disclosed herein, but is'to be accorded the full scope of the appended claims.

I claim:

1. In a drafting machine of the pulley and bandtypethe combination of; -a pulley movably mounted over a fiat surface whil its orientation with respect to said flat surface is maintained, a 1

' hollow shaft which is fixed to said pulley and can then be brought into the exact position desired by rotating the thumb piece 51 by means of the thumb and index finger of the left hand.

concentric therewith, a scale supportingmember positioned belowsaid pulley and having a second shaft fixed thereto which extends through said The con-' struction of this modification of myinvention below the support plate 14 may be exactly the"- same as the construction of the form of my inspect to said second shaft above said pulley,

and

" a worm screw fixed to said third shaft for engagement with said gear to control relative rotation of said pulley and said protractor arm, said support and said third shaft being movable to engage and disengage said worm screw and gear.

8. In a drafting machine :of the pulley and band type the combination of: a pulley movably handle on the upper end of said second shaft, a

gear fixed against rotation relative to said second iii *tatably mounted on said support and extending laterally with respect to said'second shaft above said pulley, and a worm screw fixed tosaid third shaft for engagement with said gear to control relative rotation of said pulley and said scale supporting member, said support and said third worm screw and gear.

shaft and positioned concentrically of such shaft I between said pulley and said handle, a support carried by said hollow shaft, a third shaft roshaft being movable to engage and disengage said FRANCIS E. VAUGHAN.

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

UNITED STATES PATENTS Number Name Date 965,483 Noyes July 26, 1910 2,217,008 Garner Oct. 8, 1940 2,226,882 Wallace Dec. 31, 1940 2,242,828 Langsner May 20, 1941 Langsner' Oct. 26, 1943

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