US2567733A - Drawing compass attachment - Google Patents

Description

Sept. 11, 1951 RYAN 2,567,733

DRAWING COMPASS ATTACHMENT Filed June 11, 1948 IIIIIIIIIIII INVENTOR. dlye Patented Sept. 11, 1951 UNITED STATES PATENT omcE 2,567,732. I DRAWING COMPASS ATTACHMENT George A. Ryan, Royal Qak,Mich. v Application June 11, 1948, Serial No. 32,5i2

2 Claims. (01. 32,1449) This invention generally relates to drafting instruments and more particularly pertains to a new and novel attachment for compasses which enables a lead pencil compass to not only serve for penciling drawings, but also to serve for inking the drawings as well.

An object of the invention is to eliminate duplication of penciling and inking compasses and to avoid the specially adapted pencil and pen interchangeable leg pDrtions that will fit only particular compasses of particular sizes.

Another object of the invention is to provide an inking pen attachment for the usual penciling compass which does not require any special fittings and which will fit itself to the pencil lead holder of the compass quickly and securely.

Another object of the invention is to provide an inking pen attachment for compasses which will fit the pencil lead holder of any size compass thereby enabling a draftsman to make an inking compass out of any of his pencil compasses by merely removing the lead and inserting the pen attachment in the lead chamber.

Another object of the invention is to provide an attachment for a lead penciling compass to convert the compass to an inking pen compass which is relatively cheap in cost so that a draftsman may properly equip himself with compasses of graduated size from small to large at cost far below the cost of duplicating each size compass or of buying special compasses and adapters.

These and other'objects will be apparent from the following description, the appended claims and the attached drawings in which:

Fig. 1 is a side View of a lead pencil compass equipped with the invention.

Fig. 2 is an enlarged cross-sectional view of Fig. 1 taken on the line 2-2 thereof.

Fig. 3 is an enlarged cross-sectional view of Fig. 1 taken on the line 33 thereof.

Fig. 4 is a composite view of one leg of the compass of Fig. 1 showing the pencil lead therein prior to removal and showing the invention adjacent thereto.

Fig. 5 is a perspective view of the inventive device.

Referring to the drawings, compass 20 comprises like legs 2| and 22 pivoted at 23 and held on the pivot 23 by spring 24 while the spacing between the legs 2| and 22 remote from the pivot 23 is controlled by knurled hand wheel 25 which operates right and left hand screws 26 and 21 in right and left hand nuts 28 and 29 respectively mounted in the legs 22 and 2| adjacent their centers.

The leg 2| is equipped with center point 3| held in, place by the thumb nut 33 and the leg 22 is similarlyequipped with thumb nut 32, Figs. 1 and 2, threaded on bolt 34 which ties together the forked ends of the leg 22 tightly enclosing the stud 40 of the attachment shown in dotted lines in Fig. l and in enlarged cross-section in Fig. 2.

The upper end of the stud 40 is secured in head or block 4|, Figs. 1 and 3, and also secured in block 4| is the upper end of inking pen 42, whileside 44, Fig. 5, of the block 4| is grooved to snugly fit the leg 22 of the compass as seen in Figs. 1 and 3.

The inventive attachment comprises the stud 40, the inking pen 42, and the block 4| which has a grooved face 44.

It will be noted that the pen 42 could not be directly assembled to the compass in the same manner as the pencil lead 50 as this would place the inking point of the pen 42 too far below the center point 3| to have the pen ink properly, and due to the fact that the pen must be of the double pronged spring tension type it is not possible to shorten the pen 2 to the length of the center point 3|.

In other words, the pen 42 can not be shortened and yet it must work on a level with the center point 3| which condition has heretofore necessitated duplicate compasses and/or special compasses equipped with specially interchangeable leg portions.

To utilize one compass not only for penciling but also for inking, the applicant has adapted the invention to be inserted from the top, and provides a stepped block member 4| for holding both the attaching stud 4G and the inking pen 42, and this manner and composition of attachment positions the working point of the inking pen 42 on a level with the center point 3| while the stud 40 and block 4| enable the invention to be easily secured and snugly fitted to a penciling compass as the lead itself.

In assembling the inking attachment of the invention to a pencil lead compass to convert same into an inking compass, lead 50, Fig. 4, is removed from the forked end of the leg 22 by loosening the thumb nut 32 on the bolt 34. The stud 40 of the inventive attachment is then inserted into the lead chamber of the leg 22 with the grooved side 44 nestling around the leg 22. The thumb nut is then tightened on the bolt 34 and the stud is securely held in compass leg 22.

In operation a draftsman selects a pencil compass and uses same to make his pencil drawings and he uses as many pencil compasses as necessary to best accomplish the work. Then when he desires to ink the drawings, he merely removes the lead from a compass and attaches the device of the instant invention to same which converts his penciling compass to an inking compass and he is then ready to in his pencil drawings. He may use the same inventive inking attachment on all his compasses or he may have several attachments as he prefers.

Alterations, additions, deletions and changes may be made in invention without departing from thespirit thereof as the invention is limited only by the scope of the appended claims.

I claim:

1. A drawing compass attachment comprising an inverted L-shaped head member, a leg on said head adapted to lie substantially vertically and having a recess in the back of said leg adapted to receive the arm of a compass in nesting relation therewith for preventing relative movement 'therebetween, a foot on said leg extending sub- :stantially horizontally outwardly from said leg,

a stud extending downwardly from the end of the leg portion of said head adapted to be received :in the channel of a compass leg normally carrying pencil lead for fixedly annexing said inverted L head to a compass at a point substantially above the end of the compass arm, and a pen fixedly anchored in the foot portion of said inverted L- shaped head member substantially paralleling said stud and extending downwardly beyond the end of said stud.

2. A drawing compass attachment comprising a stud downwardly insertable in a vertical chan' nel in a compass arm normally containing pencil lead; an inverted L-shaped member; a leg on said inverted L-shaped member attached to the top of said stud at the lower end of said leg, the back of said leg being recessed to partially envelop the adjacent arm of the compass to prevent relative rotation of said stud in the channel of the compass arm; a foot leading from said leg at the top thereof adapted to extend outwardly from the compass arm constituting a projection spaced outwardly away from the side of a compass arm and spaced substantially above the end of a compass arm; an inking pen attached to the underside of said foot extending downwardly therefrom and lying substantially parallel to said stud and extending beyond the end of said stud and adapted to extend beyond the end of a compass arm to which the device is attached.

GEO. A. RYAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,734,958 Audrieth Nov. 12, 1929 FOREIGN PATENTS Number Country Date 150,146 Great Britain Sept. 2, 1920

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