US2358451A - Drafting device - Google Patents

Description

Sept. 1944- c. GARDNER I 12,358.451

DRAFTING DEVICE Original Filed Nov. 1, 1939 3 Sheets-Sheet 2 Sept. 19, 1944. c. GARDNER 4 DRAFTING DEVI CE Original Filed Nov. 1, 1939 3 Sheets-Sheet 3 Patented Sept. 19, 1944 UNITED STATES PATENT, [OFFICE DRAFTI NG v Cummings Gardner, Los Angeles, Calif.

Original application November 1, 19 39,- Serial-"No.

302,282, now Patent No. 2,302,205, dated November 17:, 1942. Divided and this application April 29, 1941, Serial No. 390,891

2 Claims- (o1. 33-99) This invention relates to drafting apparatus,

and moreparticularly to devices for facilitatingis the difficulty encountered when utilizing a metal straight edge for-*inking. Th straight edge which is necessarily thin and is. invariably constructed tobe in close engagement with the surface of the paper tends to cause the ink to flow beneath the rule edge and smear the paper. When the rule edges have been thickened to over come this defect the device has become heavy and unwieldy, and impractical as. a drafting instrument. A further disadvantage of having the thin edge of a metal rule engaging the paper surface is the uncertain support the same provides for other instruments, such as triangles, brought in engagement therewith.

Accordingly, it is an object of the present in-:

vention to provide ametal drafting device having a. novel construction whereby the above menprior tioned and other objectionable features of art devices made of metal are obviated.

Another object is to; provide a novel T-square having a detachable bladeadapted to be rolled-1 up. and conveniently carried, for example; in a brief case- V A further objectis to provide av straight edge;

with novel means for-preventing the flow ofink beneath said edge. v

Still another object is to providea novel drafting apparatus made of metalwhich may be readily, rapidly andeconomically manufactured in commercial quantities and-which is durable and efiicient in operation The above and other objects and novelfeatures of the invention will more fully appear-when the following description is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for purposesv of illustrationonly and are not intended as av definition of the limits of the invention, reference beingprimarily had for thislatter-purpose to the appended claims.

In the drawings, wherein. like reference char- 7 like part throughout the several,

acters refer to views,

operatively' associated with a T-square blade;

v the IT-square 'gether; 1

'Fig. 1 is a top plan view, with parts broken" away of one embodiment of the present invention; i

Fig. 2 is a sectional view taken substantially along line 22 of Fig. 1;

Fig. 3 is a sectional View taken substantially along line 33 of Fig. 1, showingthe T-square removedifrom the drawing board;

Fig. 4 is a perspective view, with the parts' broken away, of a portion of a T-square blade formed in accordance with the present invlen tion;

Fig. 5 is an exploded perspective view, with parts broken away, showing'the manner in whichv blade endsmay be secured to.-

Fig. 6 is a sectional'view, with parts broken away, taken substantially along line 6-6 of: Fig.1;,

Fig; 7 is a top plan view; with parts broken away, of asupporting plate for a protractor unit Fig. 8 isa sectional view taken substantially along line 88 of Fig. 7;

Fig.9 is a top plan view, with parts broken away, of another embodiment of'the protractorunit;

Fig. 101s a sectional view taken substantially along line Ill-40 of Fig. 9;:

Fig. 11' isa sectional view taken substantially along line H-ll of'Fig.'9; and f Fig. 12 .isa sectional view taken along line I'2'l2 of Fig: 9; 'In the embodiment of the invention illustrated;

by way of example, in=Figs. 1 to 8 the drafting" apparatus comprises a protractonunit =l5' slidably mounted on-a -T-square lB' which, in turn,:

is operatively associated with a drawing board" H, the latter being-provided with'meansfor fas ten-ing a sheet of-paper l8, orother'drawin'g material, to'the face thereof.

Drawing board IT is preferably synthetically formed'from =a materiah'such as press'ed wood fibre, and is provided close to the 'ed'gesthereor with a plurality of indentations l9. Novel'pap'er securing means are mounted on said board in said indentations, said means compri'sing'clips' Zllfcrmed-f-romi a wire having a smaller diameter 1 than the depth of'the' indentations s'o that said" clips, when fiatlymounted, will not project beyond thesurface of board H. Each of 'clips- 20 is, preferably; fabricated from a'singl'e piece of fairly rigid resilient wire, central section 21 of said wire being shaped in'the-fbimof a circle and ends 22 of said wire extending radially to substantially approximately the center of the circle and being suitably secured at that point to the drawing board (Fig. 2). Clips are mounted somewhat eccentrically in indentations l9 which are also preferably circular, the largest space between the clip and the indentation wall being located at the side from which the paper is to beinserted. This prevents the paper from being subjected to the sharp creases and mutilation which might result if the clip was positioned too close to the indenttation' wall.

The paper is inserted between clip 20 and board [1, and is held irr position by the.

,T-square l6.

vi'desirable to have a vernier scale 4| marked on resilience of said clip, the latter not extending,

when thus operatively utilized, beyond the surface of said board, and therefore not interfering with the movement, for example, of the blade of a T-square over said board.

ed e 39 for cooperation with scale 38. An arcuate slot 42 concentric truth the arc of scale 38 is preferably formed in the portion of bracket 33 adjacent said scale and a threaded member 43 is soldered or otherwise fixed to plate 34 to T-square I 6 which engages board I! is prov vided with a novel blade 23 secured in a novel manner to a guide shoulder or head member 24 of the well-known and usual shape, said head member being formed preferably of a light metal, such as aluminum. Blade 23 is formed from a strip of flexible metal, such as thin spring steel, being sufliciently thin'and flexible to be rolled lengthwise into a circle without being in any. way permanently deformed. Means are provided for detachably securing blade 23 to head 24 (Fig. 3) and said means comprise a lug .25, preferably rectangular in shape, welded or riveted to the face of said blade at one end thereof. A recess 26 closely corresponding in shape to the shape of lug is provided in head 24 intermediate theends thereof, and when said recess receives said lug, blade 23 extends at right angles to the edge of said head. A threaded member 21 is secured'to lug 25 to extend perpendicularly therefrom and a thumb nut 28 is adapted to thread thereon to fasten head 24 to-blade 23. An opening 29 (Figs. 1 and 5) is provided in the free end of said blade and when T-square I6 is to be carried in a compact form as, for example, in a brief case, said blade is detached from head 24 and bent end to end so that opening 29 receives threaded member 21' (Fig. 5) and the blade is fixed in this position by nut 28. Blade 23 (Fig. 4) is novelly constructed to facilitate inking and to provide a proper suppo'r't'fortriangles and other instruments used in conjunction therewith, said blade having edges 30 thereof raised above the surface of the paper. This is preferably accomplished by pressing edges'30 which are formed integrally with blade 23 above the level of the remainder of said blade, said remainder constituting a centrabportion 3| adapted to engage and travel alongathe surface of the drawing paper thus elevating said edges above said paper.

. Novelprotractor'unit I5. preferably formed of metal, is operable in combination with T-square l6' 'and -inthe preferred embodiment thereof illustrated in the drawings'is, comprised of a pair of blades 32 having straight and parallel ruling edges, said blades being mounted at right angles to each other upon a frame or bracket 33. The latter, in turn, is rotatably mounted upon a base plate 34 by means of a cylindrical hub or bearin member 35 (Fig. 6) secured to or formed integrally with said plate, and extending through a circular opening 36 centrally located in said bracket, member 35 being provided with a face plate 31 or other suitable means for maintaining said bracket on said bearing member.

extend perpendicularly therefrom through said slot. Athumb nut 44 is threaded on said member and is adapted to engage the surface of bracket 33 to fix the latter against movement, thereby. fixing blades 32 at any desired angle relative to plate 34. When nut 43 is loosened, slot 42 permits the rotation of bracket 33 through an angle of substantially In order to readily position blades 32 at any of the commonly used angles, such, as 30, 45, and 60, automatic stop means are provided and preferably comprise an arcuate strip 45 secured to or-formedwith plate 34 and an element 46 fixed,as by rivets 41, to bracket 33. A stop pin 48 is'carried by said elementand is adapted to engage any one of a plurality of recesses 49 formed in strip 45, each of said recesses being adapted wh'en'engaged by said stop pin to position blades 32 at one of the common angles to T-square blade 23. The bracket can thus be fixed against inadvertent movement at selected angles without the use of thumb nut 44. To change the angle, element 46 which is resilient is lifted until pin '48 is raised above the plane of strip 45 and thereafter said element is moved together with bracket 33 and blades 32 to the desired new angle. r

i Novel means are provided for slidably mounting the above described protractor unit on T- square l6 and it is preferable to detachably mount said unit on said means, although the latter may, in some instances, be formed into-- grally with" said unit} As shown, said means comprise a plate 49 (Figs. '7 and 8) having guideways 50 and 5l formed-therewith, said guideways being spaced apart a distance equal to the width of a T-square blade 23 and being adapted to slidably receive raised edges 30 of said bladej Accordingly, although plate 49 when operatively'p'ositioned on T-square blade 23 is free to move longitudinally, it cannot be lifted from or tilted relative to the blade edges.

Protractor unit I5 is mounted on plate 49 and accurately positioned in a desired relation to said plate by engaging a pair of dowel pins 52 formed with or secured to said plate at the ends thereof and a hub member 53 fixed to said plate intermediate said dowel pins. Openings 54 are" provided in plate 34 for engaging said dowel pins and also an opening 55 (Fig. 6) for engaging said hub member, the latter opening being preferably concentric with hub member 35 of the protractor unit. A threaded screw member 56 is formed with hub member 53 and a thumb nut 51 when screwed on said threaded member securelyfixes protractor unit IS on plate 49.

Hub member 53 is suitably positioned on plate 49 to cause blades 32 to be available for drawing lines at the smallest desired angles and to have one of said blades flush with the T-square edge at angle position. Furthermore, the front edge of plate 49 which carries guideway 58 is comparatively short in length and arcuate in shape, being arcuate to keep blades 32 from striking the T-square edge and short to take up a minimum of space in front of said T- square edge. Protector unit l may be detached from plate 49 and used independently thereof.

An alternate embodiment of the protractor unit is illustrated in Figs. 9 to 12, being constructed chiefly of sheet metal which may be rapidly and economically formed, as by stamping, to the desired shape. The unit is designed to consist of a minimum number of parts adapted to be readily assembled and to be manufactured in large quantities. As shown, the unit comprises a single blade 58 pivotally mounted intermediate the ends thereof upon a supporting plate 59, said blade preferably having edges 60 thereof raised in the same manner as edges 38 of T- square blade 23. To pivotally mount blade 58, a circular indentation 6| (Fig. 10) is provided in a plate 59 and a screw 62 extends centrally through the roof of said indentation, being secured thereto in any suitable manner, such as by soldering, the head of said screw being located within said indentation and having no portion thereof projecting below the lower surface of plate 59. The upper surface of indentation 6| constitutes a, bearing surface upon which blade 58 pivots, the latter having an indentation 63 and an opening 64 therein through which screw 62 extends. A nut member 65 is adapted to be threaded on said screw to prevent inadvertent axial and pivotal displacement of blade 58 once the latter is operatively mounted on plate 59 and set for a desired angle.

A semi-circular protractor scale 66, having a geometric center which coincides with the pivotal axis of blade 58, is located on plate 59, preferably by being engraved thereon, and an opening 56a through which said scale may be viewed is provided in the portion of said blade which is adapted to overlap said scale. An index 61 is carried by said blade to indicate the angle for which said blade is set, and end 68 of the latter is preferably turned at practically a right angle to the remainder thereof to provide a grip whereby said blade may be readily moved to any desired angle.

To automatically stop blade 58 at certain angles, a stop pin 69 is carried by end 68 and openings 18 are suitably located in plate 59 in the path of said pin for receiving the latter and fixing said blade. In the illustrated embodiment, said openings are provided in an arcuate strip H which is preferably formed integrally with plate 59 by being punched therein and blade 58 which engages said stripat one end is thereby inclined slightly to the plane of said plate, being thus caused to engage the surface over which it is being used.

In order to provide means whereby the protractor unit can be guided along the straight edge of a T-square or drawing board, the single sheet of material from which plate 59 is preferably formed is bent into a fold so that a portion 12 thereof extends beneath the portion upon which blade 58 is mounted. Portion 12 has edge 13 thereof turned down to be substantially perpendicular to the plane of plate 59 and thereby provides a surface adapted to engage a straight edge and guide the protractor in motion parallel to said edge. When a line is to be drawn parallel to the straight edge with which the protractor unit is being used, blade 58 is adapted to be disposed as shown in broken line position in Fig. 9 with the edge thereof flush with the edge of plate 59.

There is thus provided a drafting device having novel means for fixing a. sheet of drawing material thereto and novel apparatus whereby lines may be drawn on said material at any angle. A novel T-square is provided having a blade made of metal, thin and flexible enough to be rolled up and have the ends secured to each other. Despite the thinness of the blade, the latter is novelly constructed to provide a good edge for drawing ink lines'and a good support for other straight edged instruments. The T-square blade is additionally adapted to have a protractor unit novelly mounted thereon for operation in combination therewith, said protractor unit being made of metal and having novel meansfor mounting and positioning the blades thereof.

Although only two embodiments of the present invention have been illustrated and described, it is to be expressly understood that the same is not limited thereto. Various changes which will now be apparent to those skilled in the art may be made in the design and arrange- 'ment of parts without departing from the spirit and scope of theinvention. For a definition of the invention, reference will be had primarily to the appended claims. 1

What is claimed is:

1. In a T-square, a blade of spring steel sufiiciently thin and flexible tobe bent end to end without permanent deformation, and means including a threaded member for detachably securing said blade to a head member and for securing the ends of said blade to each other when said blade is detached from the head member, said threaded member being rigidly secured to one end of said blade, the other end of said blade being provided with a recess adapted to receive said threaded member.

2. In a T-square, a blade of spring steel sufficiently thin and flexible to be bent end to end without permanent deformation, said blade having the longitudinal edge portions thereof extending upwardly and outwardly from the central body portion thereof, and means for securing the ends of said blade to each other when said blade is detached from its head member. 7

CUMMINGS GARDNER.

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