US3486770A - Drafting board - Google Patents

Description

Dec. 30, 1969 R. J. ANDERSON 3,486,770

DRAFTING BOARD Filed March 6, 1967 2 Sheets-Sheet l /2--- INVENTOR.

. 1) Ear J dwasercw Dec. 30, 1969 R. JJANDERSON Y 3,486,770

DRAFTING BOARD Filed March a, 1967 2 Sheets-Sheet 2 United States Patent US. Cl. 281-45 8 Claims ABSTRACT OF THE DISCLOSURE A drafting board having work sheet anchoring means which are adjustable to permit the work sheet to be quickly and easily adjusted back and forth across the board to locate any selected area of the sheet in the most convenient working position, and a chamber opening through the work surface of the table into and from which the sheet slides during adjustment in such a way that the unused portion of the sheet is located in a protected and out of the way position within the chamber. A drafting board of this kind having means for containing a supply roll of tracing paper and facilitating attachment of the paper to and adjustment of the paper with the drawing to be traced.

This invention relates to drafting equipment, and more particularly to an improved drafting board.

A variety of drafting boards have been devised. The existing boards are not totally satisfactory, however, for the reason that a work sheet on the board is not readily adjustable to locate any selected area of the sheet in a convenient working position. When working on the upper area of the work sheet, for example, the draftsman is required to stretch forwardly across the board and thus work in an uncomfortable position and perhaps damage the sheet. The lower area of the sheet, on the other hand, may be situated so close to the front edge of the board as to be difficult to work on. It is possible, of course, that a draftsman may draw on a work sheet without anchoring the sheet to the drafting board to permit adjustment of the sheet to a convenient working position. In this case, however, the work sheet is not held in the proper alignment relative to the implement guide edge of the board. Moreover, the work sheet may drape over the front edge of the board in some positions of adjustment, in which case the work sheet is prone to being soiled, creased, torn, or otherwise damaged by the draftsman as he leans over the drafting board. At this point, attention is directed to the fact that the term board is used herein in its boardest sense to encompass both simple drafting boards and true drafting tables.

Drafting frequently requires tracing of an existing drawing. The tracing paper used for this purpose is commonly contained on a supply roll which may be located some distance from the drafting board. As a result, the draftsman is required to leave the drafting board or table to obtain the tracing paper, which is inconvenient and time-consuming. Moreover, he must either guess at the proper length of tracing paper to be removed from the supply roll or measure both the original and the tracing paper to make certain that he cuts off the proper length of tracing paper. The former procedure, of course, involves an undesirable element of chance which may result in wasting of considerabl tracing paper due to cutting off of an insuflicient or an excessive length of the paper. Measuring the original drawing and the tracing paper, on the other hand, is both inconvenient and time-consuming. Anchoring of the tracing paper in the proper position over the drawing to be traced is also difficult in these cases, as is shifting of the drawing and tracing paper without misaligning the same.

3,486,770 Patented Dec. 30, 1969 It is a general object of the present invention to provide an improved drafting board which avoids the abovenoted and other deficiencies of the existing drafting boards.

A more specific object of the invention is to provide a drafting board which facilitates adjustment of a work sheet back and forth across the board to locate any selected work area on the sheet in the most convenient working position and contains the unused portion of the sheet in a protected and out of the way position within a chamber in the board, whereby draping of the work sheet over the edge of the board and the disadvantages attendant to such draping are avoided.

A related object of the invention is to provide a drafting board of the character described having novel work sheet anchoring means which maintain the exposed portion of the work sheet in a fixed, taut condition over the work surface of the board and are uniquely constructed and arranged to permit rapid and easy adjustment of the work sheet relative to the drafting board.

Another object of the invention is to provide a drafting board of the character described having means for containing a roll of tracing paper and facilitating attachment of the correct length of tracing paper in the proper position over a drawing to be traced, as well as unified adjustment of the drawing and tracing paper without misalignment of the same.

A further object of the invention is to provide a drafting board of the character described which is relatively simple in construction, economical to manufacture, and otherwise ideally suited to its intended purposes.

This invention possesses many other advantages, and has other objects which may be made more clearly ap parent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a plan view of a drafting board embodying the invention;

FIG. 2 is an enlarged section taken along the line 2-2 in FIG. 1;

FIG. 3 is an enlarged section taken along the line 3--3 in FIG. 1;

FIG. 4 is a section taken along the line 4-4 in FIG. 2;

FIG. 5 is a section taken along the line 5-5 in FIG. 2;

FIG. 6 is a section taken along the line 66 in FIG. 2;

FIG. 7 is an enlarged section taken along the line 77 in FIG. 1; and

FIG. 8 is an enlarged fragmentary plan view of the drafting board with a rear cover removed and parts broken away for clarity.

In general, the invention provides a drafting board 10 including a main member 12 having a work surface 14 for supporting a work sheet 16 whose dimensions are such as to render it desirable or necessary to periodically adjust the sheet relative to the work surface in order to locate any selected work area on the sheet in the most convenient working position. To avoid draping of the remaining, unused portion of the work sheet 16 over the edge of the member 12, and thereby the earlier noted disadvantages which attend such draping, the member 12 is provided with a narrow chamber 18 for receiving and protecting the unused portion of the work sheet. This chamber opens to the work surface 14 through an entrance guideway 20 located along one boundary of the work surface, which extends transverse to the direction line 22 of adjustment of the work sheet 16 across the surface.

In the present instance, the long dimension of the work sheet, and hence the direction line 22 along which the sheet is adjusted relative to the work surface, extend in the fore and aft direction of the drafting board. The entrance guideway is located along the front boundary of the work surface 14 between the latter and the front edge 24 of the member 12. In this case, during lengthwise adjustment of the work sheet 16 relative to and in the fore and aft direction of the work surface, the front lower end portion of the sheet feeds into and from the sheet receiving chamber 18, through its entrance guideway 20. Thus, the draftsman is able to conveniently work on any selected Work area at the upper or rear portion of the work sheet without draping of the lower front portion of the work sheet over the front edge 24 of the member 12 by shifting the sheet forwardly across the; work surface to a position wherein the selected work area is situated in a convenient working position over the surface, and in such a way that the front lower portion of the sheet feeds into the chamber 18. On the other hand, if the draftsman wishes to work on a lower area of the work sheet, he simply slides the latter rearwardly or upwardly across the work surface, and from the chamber, until the selected work area on the sheet is located in a convenient position over the work surface. The portion of the Work sheet within the chamber 18 is obviously protected from soiling, tearing, and other forms of damage, and particularly from being creased by the draftsman, as might occur if the sheet draped over the front edge 24 of the board member 12. It is also significant to note that the sheet chamber 18 is quite narrow and thus restrains the work sheet against curling. Preferably, the chamber is located directly below the member 12 and its work surface 14, and the entrance guideway 20 to the chamber is curved to open generally tangentially to the work surface and chamber, as shown. At this point, attention is directed to the fact that while the illustrated drafting board of the invention is arranged for fore and aft adjustment of the work sheet 16 across the work surface 14, the features of the invention conceivably may be embodied in a drafting board which is arranged to permit adjustment of the work sheet in a lateral direction of the board.

The present drafting board is also equipped with releasable hOlding means 26 for anchoring the exposed portion of the Work sheet 16 in a fixed position over the work surface 14. These sheet holding or anchoring means are adjustable in such a way as to facilitate adjustment of the work sheet to any desired working position and, in addition, exert opposing edgewise tension forces on the exposed portion of the sheet to retain this portion in a taut condition over the work surface. To this end, the work sheet holding means include first releasable gripping me ans 28 mounted on the member 12 along the work surface boundary adjacent the chamber entrance guideway 20, second gripping means 30 for gripping the exposed edge of the work sheet opposite the guideway, and springloaded tensioning means 32 for resiliently urging the latter gripping means toward the opposite boundary of the work surface.

Between the entrance guideway 20 to the work sheet receiving chamber 18 and the front edge 24 of the member 12 are means 33 for supporting a supply roll 33a of tracing paper. As will be presently explained, this tracing paper may be pulled from the roll over a drawing supported on the work surface 14 for making a tracing of the drawing. In this case, the griping means 28, 30 serve to grip both the tracing aper and the work sheet 16.

Referring now in greater detail to the illustrated drafting board 10, the main body member 12 has an outer panel 34, an inner panel 36, and a bottom panel 38. The outer panel 34 is rectangular in shape and ha a central rectangular opening or cutout 40 which opens through the rear edge of the panel. The inner panel 36 has substantially the same width as and is suitably secured within the cutout, as by gluing. The upper surface of this inner panel is flush with the upper surface of the outer panel 34 and defines the work surface 14. The bottom panel 38 is suitably secured to the undersurface of the outer panel, as through use of the screws 38a. In the illustrated embodiment of the invention, the work sheet chamber 18 is defined between the inner and bottom panels. To this end, the inner panel 36 has a thickness less than that of the outer panel 34, such that the confronting surfaces of the inner and bottom panels 36, 38 are spaced to define the. chamber 18 therebetween, as shown. The front edge 42 of the inner panel 36 and the confronting front edge 44 of the cutout 40 are disposed in spaced generally parallel relation to define therebetween the entrance guideway 20 to the chamber 18.

It is significant to note here that the front edge 42 of the inner panel 36 is convexly rounded and merges tangentially with the upper Work surface and the undersurface of the panel. The front edge 44 of the cutout has an upper convexly rounded portion which curves forwardly toward the front edge 24 of and merges tangentially with the upper surface of the member 34, and a lower concavely rounded portion which curves rearwardly and merges tangentially with the upper surface of the bottom panel 38. At this point, therefore, it is evident that the work sheet 16 can slide freely into and from the work sheet chamber 18, through its entrance guideway 20, during fore and aft adjustment of the work sheet across the work surface 14.

The work sheet gripping means 28 comprise a long, narrow clamp plate 46, the forward edge of which is slotted at intervals to define a number of hinge portions 48 and intervening tabs 50. The hinge portions 48 of the plate are curled about a hinge rod 52, which is supported at its ends in upstanding brackets 54 secured to the upper surface of the member 12, between the entrance guideway 20 and the front edge 24 of the member. Hinge rod 52 parallels the front edge 24 and cooperates with the hinge portions 48 of the clamp plate 46 to pivotally support the plate for hinging movement about the axis of the rod. The clamp plate tables extend outwardly a distance beyond the hinge rod and then turn back toward the rod to define cams on the clamp plate. These cams bear against leaf springs 56 mounted in grooves or recesses 58 in the member 12. The rear edge portion of the clamp plate 46 has a generally V-shaped bend defining a longitudinal tongue 60 on the plate. Along the rear edge of the clamp plate is a longitudinal clamping head 62.

The clamp plate 46 is rotatable between its solid line closed or clamping position of FIG. 2 and its phantom line open or released position of FIG. 2. During movement of the clamping plate between these positions, the clamp plate cams 50 rotate through intermediate dead center positions relative to the cam springs 56 in such a way that the springs and the cams are effective to yieldably retain the plate in each position. In its closed position, the forward edge of the clamp plate overlies the sheet chamber entrance guideway 20 and the tracing paper supply roll 33a, and the clamping bead 62 on the plate bears against the work surface 14, just forwardly of the guideway. The clamp plate tongue 60 projects downwardly into and generally complements the upper portion of the guideway, as shown. In its open position, the clamp plate exposes the guideway and the tracing paper supply roll.

The rear sheet gripping means 30 comprise a pair of spring clips 64 of any suitable design. These clips have spring-loaded jaws which may be separated to receive therebetween the upper rear edge of the work sheet 16 and then released to grip the sheet. Secured to the sheet clips 64 are the tensioning means 32. These tensioning means comprise cables 68, the forward ends of which are attached to the clips in any convenient way. The rear ends of the cables extend rearwardly across the work surface 14 and into a spring chamber 70 at the rear of the surface through entrance guides 72. Spring chamber 70 is defined by the rear end of the opening or cutout 40 in the outer panel 34, are movable cover 74, and the bottom panel 38. In this regard, note that the rear end of the inner panel 36 is spaced a distance from the rear end of the cutout to provide a clearance for the chamber. Cover 74 has a generally L-shaped in vertical fore and aft cross-section and includes a top plate 76 and a rear plate 78 depending from the rear edge of the top plate. The ends of these cover plates engage in seats 80 recessed into the upper surface and rear edge of the member 12 at opposite sides of the cutout 40, as shown, in such a way that the top plate is flush with the work surface 14. The cover is releasably secured in position by screws 82 and closes the top and back sides of the spring chamber 70. The cable entrance guides 72 comprise inclined slots or grooves which are cut into the rear edge of the inner panel 36 and the front edge of the top cover plate 76, as shown.

Within the spring chamber 70 are a pair of elongate barrels or housings 84 containing coil springs 86. These barrels are rigidly mounted in the chamber by brackets 88 in such a way that the barrels extend parallel to the front and rear edges of the member 12. Each barrel has an open end adjacent one of the cable entrance guides 72.

The rear ends of the cable 68 are trained about pulleys 90 rotatably mounted within the spring chamber 70 in such a way that each pulley is tangent to both the axis of one cable entrance guide 72 and the axis of the adjacent spring barrel 84. After passing around its pulley,

each cable enters the open end of the adjacent barrel and is secured to the end of the spring, the opposite end of each spring being secured to the end of its containing barrel.

It is now evident, therefore, that the springs 86 in the spring barrels 84 yieldably urge the spring clips 64 rear wardly across the Work surface 14. The cables 68 are so longitudinally dimensioned that the springs are just about, but not quite fully, retracted when the clips occupy their rear limiting positions, adjacent the cable entrance guide 72.

In the use of the drafting board 10, the work sheet 16 is placed on the work surface 14 in such a way that its long dimension extends in the fore and aft direction of the table. The clamp plate 46 is now released and the lower front end portion of the sheet is inserted under the plate and into the chamber 18 to the desired extent. The clamp plate is then shifted to grip the work sheet along the clamping head 62 on the plate. The spring clips 64 are pulled forwardly across the work surface 14 and clamped to the upper rear edge of the work sheet. When the clips are released, the clip biasing springs 86 urge the clips rearwardly, thereby tensioning the exposed portion of the work sheet between the clamping plate and the clips. When the draftsman finds it desirable or necessary to shift the work sheet 16, in order to locate a selected work area on the sheet in convenient working position over the work surface 14, he releases the clamp plate 46 and slides the work sheet forwardly or rearwardly across the work surface, depending upon the location of the selected work area on the sheet. For example, if the selected work area is located adjacent the top rear edge of the work sheet, the latter is moved forwardly across the work surface. On the other hand, if the selected work area is located adjacent the lower front edge of the work sheet, the latter is moved rearwardly across the work surface. After the work sheet 16 has been properly positioned, the clamp plate 46 is returned to its clamping position to grip the work sheet.

When the work sheet 16 is shifted forwardly across the work surface 14, the lower front end portion of the sheet feeds into the work sheet receiving chamber 18 through its entrance guideway 20 and is thereby protected against damage. In this regard, it is significant to note that the rear surface of the tongue 60 on the clamp plate 46 is concavely rounded to serve as a guide for directing the work sheet downwardly through the entrance guideway into the chamber. The side edges of the member 12 of the drafting board define straight edges against which a T-square T or other drafting implements may be engaged to locate such implements relative to the work surface 14.

When a tracing is to be made of an existing drawing, the latter is placed on the work surface 14 and the clamp plate 46 is opened to expose the tracing paper supply roll 33a. The tracing paper is then pulled from this roll forwardly over the drawing on the work surface until the upper edge of the tracing paper and the upper edge of the drawing are substantially flush. These upper edges of the tracing paper and sheet 16 are then secured to the spring clips 64. Thereafter, the clamp plate 46 is returned to its closed position to grip both the tracing paper and the drawing. In this case, the sheet-holding means 26 serve to anchor and tension both the drawing sheet 16 and the tracing paper. Moreover, the spring clips 64 are effective to retain the drawing sheet and tracing paper in alignment and thereby permit unified adjustment of the sheet 16 and tracing paper in the fore and aft direction across the work surface to a convenient working position in much the same way as described with reference to the work sheet 16 alone. In order to facilitate such unified adjustment of the tracing paper and work sheet 16, the supporting means 33 for the tracing paper supply roll 33a preferably comprises a springloaded roller 92, similar to a window shade roller, which is tensioned to wind the tracing paper onto the supply roll. In this way, the tracing paper is maintained in a taut condition during its adjustment with the drawing sheet in the fore and .aft direction across the work surface. The completed tracing may be severed from the supply roll without the necessity of guessing or measuring the correct length of tracing paper.

I claim:

1. A drafting board: comprising a board member having an upper surface adapted to support a work sheet, said board member including a chamber having an entrance guideway opening to said upper surface at the front portion of said member, the work sheet being insertable through said guideway into said chamber and adapted to overlie said upper surface, releasable clamping means on the board member adjacent said entrance guideway for releasably clamping the work sheet against such front portion in various positions of the work sheet on the upper surface and in said chamber, means urging said clamping means toward said front portion to clamp the work sheet therebetween, release of said clamping means permitting movement of the work sheet along said surface and in said entrance guideway and chamber, tension means including flexible cable means extending from the rear of said member toward the front thereof and overlying said upper surface and adapted to be releasably secured to the rear margin of the work sheet to exert a rearward pull on the work sheet and thereby retain the work sheet in a taut condition, said flexible cable means having a large range of movement over said upper surface to permit retention of the work sheet in the taut conditi n in various positions of adjustment on said upper surface.

2. In a drafting board as defined in claim 1, said tension means further including springs attached to said cable means to exert a rearward pull on said cable means and work sheet.

3. In a drafting board as defined in claim 1, said tension means further including springs attached to said cable means to exert a rearward pull on said cable means and work sheet, said releasable clamping means including a clamp plate adapted to clamp the work sheet between it and said front portion.

4. In a drafting board as defined in claim 1, said tension means further including springs attached to said cable means to exert a rearward pull on said cable means and work sheet, said releasable clamping means including a pivoted clamp plate adapted to clamp the work sheet between it and said front portion, and said urging means comprising spring means engaging said clamp plate to retain said clamp plate clamped against the work sheet.

5. In a drafting board as defined in claim 1, said tension means further including pulleys at the rear p rtion of said member over which said cable means pass, and tension springs attached to said cable means to pull said cable means over said pulleys and cause said cable means to exert a pull on the work sheet.

6. In a drafting board as defined in claim 1, said tension means further including pulleys at the rear portion of said member over which said cable means pass, tension springs attached to said cable means to pull said cable means over said pulleys and cause said cable means to exert a pull on the work sheet, said releasable clamping means including a pivoted clamp plate adapted to clamp the work sheet between it and said front portion, and said urging means comprising spring means engaging said clamp plate to force it against the work sheet.

7. In a drafting board as defined in claim 1, said tension means further including springs attached to said cable means to exert a rearward pull on said cable means and Work sheet, means for supporting a supply roll of tracing paper at the front portion of the member which may be pulled over the work sheet on said upper surface for attachment to said cable means, and said releasable clamping means being also adapted to secure the tracing paper to the front portion of the member.

8. In a drafting board as defined in claim 1, said tension means further including springs attached to said cable means to exert a rearward pull on said cable means and work sheet, means for supporting a supply roll of tracing paper at the front portion of the member which may be pulled over the work sheet on said upper surface for attachment to said cable means, said releasable clamping means including a clamp plate adapted to clamp the tracing paper and work sheet between it and said front portion.

UNITED STATES PATENTS References Cited 354,347 12/1886 Richards 281-7 727,109 5/1903 Dorr 2816 3,330,580 7/1967 Vanek 28144 791,942 6/1905 Poignant et al. 281-7 1,003,766 9/1911 Little 3379 1,165,720 12/1915 Seelman 2816 1,208,024 12/1916 Sinclair. 1,934,952 11/1933 Shoemaker 3376 X 1,985,212 12/1934 DFarrell 33-80 2,688,818 9/1954 J0 108 50 1,844,744 2/ 1932 Critchfield. 1,892,721 1/1933 Cardarell 28144 JERMOE SCHNALL, Primary Examiner US. Cl. X.R.

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