US1843824A - Rotatable drawing board and attached straightedge - Google Patents

Description

Feb. 2, 1932. A. LA FRANCE 1,843,824

ROTATABLE DRAWING BOARD AND ATTACHED STRAIGHTEDGE Filed Oct. 23, 1929 3 Sheets-Sheet 1 sllllllllllu lllllll WM Qa/ww A TTORNEY.

A. A FRANCE 1,843,824

ROTATABLE DRAWING BOARD AND ATTACHED STRAIGHTEDGE Feb. 2, 1932.

Filed Oct. 23, 1929 3 Sheets-Sheet l.:: @hipo INVENToR. f77/fred a Fance mgm ATTORNEY.

INVENTOR.

ATTORNEY.

3 Sheets-Sheet 3 A. LA FRANCE Filed oct. 2s, 1929 ROTATABLE DRAWING BOARD AND ATTACHED STRAIGHTEDGE Feb. 2, 1932.

Patented Feb. 2, 1932 leisen PATENT OFFCE ALFRED LA FRANCE, F CENTRAL FALLS, RHODE ISLAND RoTA'rAisLEnRAWING Bom AND AT'rAeHED STRAIGHTEDGE .Application led October" 23, 1929; rSerial No. 401,760.

This invention relates to a .draf/ ting device, the Ageneral object of the invention being to provide a device which will take the place vof a vruimt-rer of the instrumentsnow tt? used, so'that it isnot necessary to pick up or lay aside `such instruments, and it eliminates the use of triangles.

`A further object of the invention is to provide means whereby al1 .lines are drawn 10 in a-lhorizontal position anda .line can be drawnvat iany-'angle and the Jull Width of the board.l

This invention also consists in certain other Afea-tures of construct-iemand in the 'combi- 35 nation and arrangementfof the several parts, to gbe hereinatfter :fully described, illustrated in the accompanying drawings .and specifically pointedoutin the appended claims.

v-In describing the invention detail, reference Will be haizlitothe acconrpanying'drawings 'Whereinlilre characters denotelliike or corresponding parts :throughout the Asearer-al views,'andiinvvhich:-

Figure f1 V'isla 'pl-an View of fthe device.

` Z5 Figure 2 is an edge View. i Y

Figure'i'Svis fafsimilarview, buttaiken at right angles to Figure 2. y

Fligumef'isasection on line -4-4 01'?V 'Fig- 11ml, i 'fsf'. il I Figure 5 -a section :onl fline 5.-5 Iof Figure 1. i l

Figure 6-` is a section online 6-6 of Figura''.. Y

Figureff? fis'. a plan iview', 'partly in section, fshowing'the'nieans for controlling' the movevment-.of fthe fturntable.

/ Figua'e lis aftop plan view with the square strip. removed and-showing the -means for adjusting thesquare over :the board.

Figure 9 is a section on line 9-9 of Figure'fS. l

Figure 1i0is1asection on line 10-10 of Figure 9. r

In these views, lthe numeral 1 indicates the ysupporting ,-mem'ber to which the turntable 2-is 4pivoted at itscenter, :as shownat 3, the upper partv of vthe .supporting member being recessed tax-receive the table so that the table is :Hush with the .upper surface of said niem- 59 iber. A aboard 4 is-.zremovably placed on `the table and is caused to turn Vtherewith by means of the projection 5 on the table 'engagin'g a vnotch `r6 in the board. The board is of .less diameter than 'the table so .that the periphery of the table is exposed and a portion of 'the periphery of the table is formed with the teeth 7 which formv graduatio'ns on the table and these graduations are divided into tenths by the vnumerals and lines 8. A bar :9 is arranged Ain a space in the -supporting member and has an arm 10 intermediate its ends which 'carries a pin 11 projecting through a hole 12 in the supporting member and adapted to engageV the teeth 7, the pin being norm-ally held infengagement with the teeth by the spring 13 which connects the central lfpart of rthelbar -With fa part 'of the supporting member. One end of the bar 9 is pivoted -to an arm 14 arranged in an opening 15 :in the supporting member, vand this arm is connected by a--screvv` 1'6 with an arm 17 `which operates -over Ya plate 18 on the supporting'member, said plate having a lhole 19 therein through-which apa-rt 14 of the anni '14 extends, so that thetvvov `arms are pivotally supported by the plate, and the movement `of fthe outer arm l17 will becommunicafted tothe arm 14. The plate carries a fraised portion 2'() having .a vernier on its upper Vsnrae'e :and :a "spring .plunger 21 is carried-by the vfarm 17 and frictionally engages the inner :Wall of the enlargement 20 so that this plunger acts to hold :the arm 17 in adjusted position. The other Iend of the bar 9 Jhas a slottherein vfor receiving a headed pin22 'depending from an arm 23 having a'bearin-gfpart 2.4 passing through a hole in a plate :25 carried by the supporting member and an :a'rmk26 is fastened to the bearing part and operates over the plate 25 so that by vmoving vthis arm 26, the arm 23 is -moved and this movement of the arm 23 Will swing the bar I'9 outwardly against the action of its spring and thus move the pln 11 out of engagement with the toothed p0rtion of the table so that the table is free to move. The arm 26 carries a spring plunger 27 which isadapted to engage a hole 28 in the plate 25 When the arm is moved to a posit-ion to swing the bar 9outwardly, thus holding the bar in this position against the action of its spring 13. The arms 17 and 14 act to move the bar 9 longitudinally and thus cause the pin 11 to move the table a certain distance on its pivot 3 and this distance can be accurately gauged by the von nier on the enlargement 20.

From the foregoing it Will be seen that the table can be accurately moved by moving the arm 17 to certain distances and by mov` ing the bar 9 by the arm 26, the table Will be freed of the pin 11 so that the table can be turned freely to any desired position.

A guide bar 29 is supported at -one edge of the board by the projections 30, this bar having a reduced lower part which is formed with the raclt teeth 31 on its inner edge and a channel shaped member 32 is slidably arranged on the bar and is formed with a casing 33 at its center. A graduated elongated plate 34 has one end fastened to the casing by the screws 35 and this plate 34 and the member 32 forms a T square. That end of the plate 34 which is connected With the casing forms a cover for the casing. A pressure bar 36 is arranged in the casing and carries a roller 37 at its inner end for engaging the inner edge of the bar 29 and said bar 36 carries a spring 38 which is forced against a part of the casing by a thumb screw 39 threaded in the outer end of the member 36. Thus this bar and its parts act to frictionally connect the casing with the bar 29, and the frietional engagement of the roller with the bar 29 can be controlled by adjustment of the spring 38 by the screw 39. A lever 40 is pivoted in the casing and has a projection 4l thereon engaging a notch in the member 36` with one end of the lever projecting outwardly from the casing. Thus by pressing upon the outer end of this lever and against a handle 42 connected with the casing, the bar 36 is moved inwardly so as to move the roller 37 away from the bar 29 and thus permit the member 32 to have free movement on the bar 29.

A lever 43 is nivoted in the casing between the lever 40 and the handle 42 and the inner end of this lever 43 has a dog 44 pivoted thereto, with the dog engaging the rack teeth 31. The dog 44 is frictionally connected with the lever 43, as shown at 45, and aspring 46 normally holds the .lever with its inner end against a Wall of the casing and the dog retracted.

A combined lever and pointer 47 is frictionally pivoted to a part of the casing and has its pointed end passing through the casing and this pointed' end operates over a scale 48 on the member 32. The inner part of the lever carries a depending projection 49 which extends into the path of the pawl and acts to control the movement of the pawl by the lever 43. W'hen the lever 47 is on the graduation l of the scale 48, the paWl has but a limited movement so that when the pavvl is operated by the lever 43, the T square is moved but one step on the bar 31, but when the lever 47 has its pointed end opposite the graduation 4, the T square 1s moved four steps or over four teeth 31 every time the paivl is moved by the lever 43. I

Thus it will be seen that by pressing With the thumb and a finger of one hand upon the handle 42 and the lever 40, the friction bar 36 is moved to position the roller 37 out of Contact with the guide bar 29 so that the T square can be adjusted to any position over theY board on the turntable and by' placing the thumb and finger on the handle 42 and the lever 43 and applying pressure upon the lever 43, the T square is moved by the dog a certain distance, this distance being controlled by the positioning of the level' 47 on the scale 48. Thus it will be seen that I have provided a device which Will take the place of a number of instruments now used in drafting, with all the controls at the fingertips. ready to operate Without having to pick up 'or lay aside different instruments. Thel T square will remain in a set position when the board is inclined and it can be adjusted to any desired position on the board and the board can be turned to draw lines on the sheet thereon, through means of the T square, at any angle and tliefull Width of the board. The board and the turntable can revolve in either direction and it can be locked at every degree and can be shifted in fractions of a degree While in locked position. The lock can be moved ,to inoperative position and held there so that the board can be turned at Will'. The member 32 has slight tilting movement on the bar 29 so that by slight pressure upon the handle,

the square can be raised above the board so'A that it will pass over thumb tacks or the like.

While the drawings show the board on the turntable of circular shape, it will, of course, be understood that any shape of board can be placed thereon.

It is thought from the foregoing description that the advantages and novel features of the invention Will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts, provided that such changes fall Within the scope of the appended claims.

What I claim is 1. A drafting instrument comprising a supporting member, a turntable thereon, locking means for the same, means for adjusting the table when in locked position, a guide bar on the. supporting means, a T-square slidably arranged on the bar, adjustable means for frictionally holding the square against movement, a lever for moving the friction means into inoperative position, said guide bar having rack teeth thereon, a pawl carried by a part of the T square and engaging the teeth, a lever for operating the pawl, a second lever for controlling the amount of movementl of the pawl by the lever.

2. A drafting instrument comprising a. supporting member, a turntable thereon, looking means for the same, means for adjusting the table when in locked position, a guide bar on the supporting means, a T square slidably arranged on the bar, adjustable means for frictionally holding the square against movement, a lever for moving the friction means into inoperative position, said guide bar having rack teeth thereon, a pawl' carried by a part of the T square and engaging the teeth, a lever for operating the pawl, a second lever for controlling the amount of movement of the paWl by the lever, a scale for facilitating the ad'ustment of the control lever and means Where y the square can be tilted on the guide bar to raise the same above the table.

In testimony whereof I aix my signature.

ALFRED LA FRANCE.

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