US1398090A - Attachment for drawing-boards - Google Patents

Description

Patented Nov. 22, 1921.

d7 7 1% 15 3 7 J0 rwelmr 62a; jeciafimrua UNITED STATES PATENT OFFICE.

CARL F. DIECKMANN, OF CHICAGO, ILLINOIS, ASSIGNOR TO EUGENE DIETZGEN COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

ATTACHMENT FOR DRAWING-BOARDS.

Application filed June 28,

T 0 all whom it may concern Be it known that I, CARL F. DmoKMANN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Attachments for Drawing-Boards, of which the following is a specification.

My invention relates to attachments for drawing boards of the type used by draftsmen and others in conjunction with the T squares and other drawing instruments. The object of the invention is to provide means for holding the head of the T square in firm contact with the working edge of the board. Parallel ruling attachments are, of course, well known. but in the commonest type the straight edge is controlled at both ends, that is, the straight edge extends entirely across the board, and the mechanism which forms the attachment is located at both the left and right edges of the board. This has several disadvantages. In the first place, the mechanism needs to be more or less elaborate and correspondingly expensive and cumbersome, and in the second place it is necessary for the straight edge to extend entirely across the board. thus sweeping over the entire surface of the paper every time the straight edge is shifted up or down the board. Draftsmen like to keep their principal drawing instruments on the surface of the board, but this is impractical where the straight edge extends entirely across it and hence leaves no free area upon which the instruments may be left. My purpose is to provide an attachment for an ordinary T square which may extend entirely across the board if desired. but at the same time may be considerably shorter, thus leaving room at the right edge of the board for the tools of the draftsman or artist. Another object is to provide means which may be located entirely at one end of the straight edge or T square, thus simplifying the apparatus and correspondingly reducing its cost. Straight edges controlled at the two opposite edges are not always free from lost motion at one end or the other and hence are not always accurate nor sure to move strictly parallel to themselves. One of the objects of my invention is to provide apparatus which, while operating at one end only of the straight edge, keeps it accurately in contact with the working edge of Specification of Letters Patent.

Patented Nov. 22, 1921.

1920. Serial No. 392,388.

the board, and hence causes the straight edge to move strictly parallel to itself. Another object is to provide apparatus which may be quickly and easily applied to ordinary T squares and boards, not calling for any special construction of the parts nor elaborate tools for applying or removing them.

I obtain my objects by the mechanism illustrated in the accompanying drawings in which- Figure 1 is a perspective assembly view showing the apparatus in use.

Fig. 2 is a view from the back of the board showing the construction more in detail.

Fig. is an edge view of the working edge of the board showing the T square and special apparatus in place.

Like numerals denote like parts throughout the several views.

The board 1 is of ordinary standard type, being rectangular and having a working edge 2 at the left. If desired, a pair of cleats 3 may be secured to the under side for strengthening it. The T square is of standard design, having a blade or straight edge 1 and a head 5 adapted to travel along the working edge of the board.

Referring now more particularly to the parts more intimately associated with my invention, a sheave 8 is mounted on the under side of the head of the T square, preferably by means of a hanger 10. This hanger is so constructed as to hold the sheave parallel to the plane of the head of the T square, near the under surface thereof. A cord 12 is fastened at one end to one end of the working edge of the board. This may be accomplished by means of a screw eye 13 or other appropriate device. At the other end of the working edge is a sheave 14 mounted in a hanger 15. The hanger is preferably fastened in such manner as to hold the center of the sheave approximately opposite to the corner of the board and at a slight distance therefrom. The cord is trained around this sheave and at its free end secured to a tension spring 16, the far end of which is anchored to the board, for example. by a screw eye 18 or other appropriate device. The parts are so proportioned and arranged that the sheave 8 deflects the cord outward away from the working edge of the board. Diflerently stated, the point of attachment of the cord to the board and course, be regulated by regulating the tension of the spring, but under ordinary circumstances great tension is not necessary to hold the T square head firmly in contact with the working edge of the board. As sheave 8 is free to rotate in its hanger, the T'square may be readily shifted up or down along the working edge, and as the acting portion of the cord (extending from the attaching means 13 to the sheave 14) :is by preference spaced somewhat away fromthe edge, there is nothing to prevent the T square from being moved practically the entire distance of the hoard iroin top to bottom. If at any time it is desired to detach the T square it may be very easily accomplished, for all that is necessary is-to lift the cord out of the groove in the sheave .8. It will be noted ihat'no special design of board or T square is called for, and the attachment may be applied toany board and T square simply by fasteningthe hanger 14 to the bottom of the T square head, the hanger 15 to the board, and inserting the screw eyes 13 and 18. As the T square is thus anchored at only one end, its length is immaterial and it may extend entirely across the board or may stop short of it, in the latter case affording space for the tools of the user.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

In combination, a drawing; board, a T square which is shorter than the board and holding; means at the head only of the .1 square for holding it in contact with the working edge'of the board, said holding means comprising a sheave on the head of the T square, a cord fastened to the board atone-end of the workingedrre and training thence around the outside of said sheave, a

second sheave at the opposite end of the working: edge of the board, and-a coiled extension spring" adjacent .to but approximately t right angles to the working edge and lying); in the plane of the board, said spring being anchored at one end to the board and at the other end fastened to the cord for holding; it trained around said sec ond sheave.

In witness whereof, I have hereunto subscribed my name. 7

CARL r. DIECKMAIIN;

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