US2734274A

US2734274A - Perspective drawing instrument

Info

Publication number: US2734274A
Authority: US
Publication date: 1956-02-14
Anticipated expiration: 1973-02-14

Description

Feb. 14, 1956 A SAMS PERSPECTIVE DRAWING INSTRUMENT Filed June 19, 1952 INVENTOR. Arman/filler 80/228 ATTURAEKS United States Patent O PERSPECTIVE DRAWING INSTRUMENT Arthur Miller Sams, Kearns, Utah Application June19, 1952, Serial No. 294,347

1 Claim. (Cl. 33--77) This invention relates to drafting instruments for use in drawing perspective-like views.

Principal objects and features of this invention are to provide a very simply constructed, inexpensive and easily manipulated instrument that may be used by a draftsman for drawing perspective views, anywhere on a drawing surface.

Other objects and features of the invention are the provision of a simple drafting instrument for making perspective drawings wherein elements determining selectively positioned vanishing points for such a drawing may be applied removably at any location on the drawing surface without the use of any other tools and other parts of the instrument positioned freely on the surface for operation relative to the established vanishing points and as freely removed from and replaced upon said surface in operating relationship relative to the established vanishing points.

Further objects and features of the invention are the provision of an effective perspective drawing instrument having few parts that are simple and cheap to manufacture and assemble and which has long life and provides accurate, simple means for making perspective drawings while permitting ready use of other instruments on the drawing surface as required.

Other objects and features of the invention will become apparent from the following specification and the accompanying drawings, wherein:

Fig. l is a plan view of a drawing instrument embodying the invention, also illustrating the manner of its use;

Fig. 2 is a sectional perspective view taken along line IIII of Fig. l; and

Fig. 3 is a sectional view of a modified construction.

Referring to the drawing, denotes a base element that in the embodiment shown has substantially trapezoidal shape with its widest or base edge 11 at the bottom. An arm 12 having parallel

beveled side edges

13 and 14 is secured to or integrally formed with the base element 10 extending from the upper edge 15 of the base element 10 with said side edge perpendicularly disposed relative to said base edge 11. One edge 13 or, if desired, both

beveled edges

13 and 14 have an ap propriate scale, for example, in inches embedded or otherwise marked thereon. The base element It and arm 12 may, for example, be of transparent plastic composition similar to that conventionally used for drafting triangles and the like. suitable materials.

A handle 16' is secured, for example, by screws 17 or the like to the upper face of the base element 10. This handle has suitable shape for hand manipulation of the base element 10 if the device is intended to be used with a T-square, or may have required shape to provide attachment to a conventional drafting machine (not shown).

A pair of straight edge arms 18 and 18a each having They may be of other parallel side

beveled edges

19, 20, 19a and 20a are secured to the respective elements 21, 21a. The elements 21, 21a are either integrally formed with the arms 18 and 18a or permanently secured thereto in any desirable way. The arms 18 and 18a and elements 21 and 21a are preferablyof the same material as base element 10. The elements 21 and 21a are rotatively supported from pivots 22, 22:: on the base element 10 so that the two arms 18 and 18a may swing independently on their respective pivots relative to said base for any desired angular adjustment relative thereto and to the opposite sides of the fixed arm 12. Outwardly diminishing scales are appropriately provided on

beveled edges

19, 20, 19a and 20a of the pivoted arms 18 and 18a.

The elements 21 and 21a support the respective arms 18 and 18a so that the under faces of said arms are coplanar or parallel with the bottom faces of the base element 10 and of the arm 12. The arms 18 and 18a have the respective longitudinally extending slots or grooves 23, 23a which extend in parallelism with the

beveled side edges

19, 20, 19a and 20a of the said arms 18 and 18a.

Anchor pins 24, 24a secured respectively to project perpendicularly from the upper faces of anchor plates 25, 25a are provided. The pins 24, 24a are dimensioned to fit slidably in the respective grooves 23, 23a of said arms 18 and 18a from the under face of each arm. The pins 24, 24a and anchor plates 25, 25a are preferably of stainless steel or other suitable material. The plates are very thin so that they will not unduly space the bottom faces of arms 18 and 18a from the drawing surface when in use. Each anchor plate is adapted to be removably fixed on the surface of the drawing paper on which a perspective view is to be drawn by the use of strips 26, 26a of conventional drafting tape with the pins 24, 24a extending slidably into the corresponding grooves latter,

To use the instrument, the respective anchor plates 25 and 25a are fixed to the drawing surface at selected locations so that their pins 24, 24a will serve respectively to determine desirably located vanishing points for a perspective drawing, for example, the drawing D of Fig. 1. The base element 10 and its pivotally carried arms 18 and 18a are then placed on the drawing surface so that the pins 24, 24a lie in the respective grooves 23, 23a of the arms 18, 18a and so that the base edge 11 of element 10 rests slidably on the edge 27 of a T- square 28. Such position of base element 10 maintains the arm 12 of said base element 10 in a perpendicular position relative to the T-square edge 11. The arms 18 and 18a because of their groove sliding engagement with anchor pins 24, 24a and because of their pivotal support on pivots 22 and 22a from the base element 10 are free for angular adjustment.

Drawing D is then readily drawn by sliding edge 11 of base element 10 along the upper edge 27 of the T square 28 to draw the required perpendicular lines of said drawing. Similarly, the

parallel edges

19, 20 and 19a, 20a of respective arms 18 and 18a are utilized to draw the respective rightwardly and leftwardly converging lines of said drawing D. Because of the predetermined fixed positions of the vanishing points as controlled by the locations of anchor pins 24, 24a, all rightwardly directed lines will converge toward a van- 'ishing point determined by the fixed right anchor pin 24 and all leftwardly directed lines will converge towards a vanishing point determined by the fixed anchor pin 24a. The drawing D is readily completed by vertical shift of the T-square 28 and by horizontal shift of the base element 10 along the edge 27 of said T-square. The dimensions of various parts of the drawing D are determined readily by use of the scales on the arm 12 by re engaging the pins24, 24a in the grooves of the arms 18 and 18a. "If the perspective drawing instrument is attached to a'drafting machine by means of its member 16, the operation is substantially the same except that the need for one T-square28 is eliminated.

Different vanishing points for other drawings are easily and quickly established by stripping tapes 26, 26.", from the anchor plates 25, 25a and drawing surface and repositioning the plates at selected new locations with fresh strips 26,260 of drafting tape.

If desired, the guide slots or grooves 23, 23a may be replaced by guide slots 30 extending the full depth of arms 18 or 13a. The pins 31 like pins 24 or 24a on anchor plates 32 like plates 25 or 250 are lengthened to project entirely through the slots and are provided with heads 33 at their upper ends to eifect a permanent attachment between the anchor plates 25, 25a and arms 18, 18a. The pins 31, however, remain slidable in the guide slots 30 and operation of this modification is the same as that of the first. With such embodiment possible loss or misplacement of anchor plates 32 is avoided.

In both modifications, when the instrument is to be used with'a drafting machine, the handle is in the form of a chuck block that fits conventional drafting machines. If used with a T-square, an additional knob is attached to the handle or to arm 12.

In connection with operation of either modification, the need for a drafting machine or a T-square to maintain the arm 12 vertical can beeliminated if vertical guide lines appear, for example, under tracing paper upon which perspective drawings are to be made.

In making some drawings, also, the arm 12 need not be maintained in vertical condition. Also, during inking, since the arms 18 and 18a are removable from their pivotal supports, one of these arms at a time may be utilized. The inking in of a drawing or the use a of lettering instruments is simple because all the arms 12, 18 and 18a remain in any desired position on the drawing surface and there is no'tension whatever on any part.

While specific embodiments of the invention have been disclosed, variations in structural detail within the scope of the claim are possible and are contemplated. There is no intention, therefore, of limitation to the exact details shown and described.

What is claimed is: i

A drafting instrument for making perspective-like drawings comprising a base element having substantially trapezoidal shape and including a pair of parallel edges, a handle secured to said base element for moving the latter over a drawing surface, an arm secured directly to said base element in fixed relationship thereto and extending perpendicularly from one of said pair of parallel edges, 21 pair of arms supported pivotally from said base element and adjustable independently to different angular positions relative to said first-named arm on opposite side edges thereof, each of said pivotally supported arms having a longitudinally extending guide groove located in its under face and extending only partially through each such arm, all under faces of. said arms and said base elements being substantially coplanar, and a pair of plate-like anchor members each independently and removably attachable to a drawing surface, each anchor member including a vertically upstanding pin for slidable engagement in the groove of respective onces of said pair of arms, whereby the respective pins provide selectively positionable pivot points for the arms to facilitate the preparation of perspective-like drawings, and tape means for temporarily securing each of said plate-like anchor members to said drawing surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,691,118 Lissy Nov. 13, 1928 2,073,881 Ronnquist Mar. 16, 1937 2,478,751 De Postels Aug. 9, 1.949

2,515,357 Reeves July 18, 1950 2,590,252 Hurst et al Mar. 25, 1952 FOREIGN PATENTS 300,974 Italy Sept. 23, 1932