US2320603A - Drafting instrument - Google Patents

Description

June 1, 1943. J. T. IVY

DRAFTING INSTRUMENT Filed Aug. 29, 1942 2 Sheets-Sheet 1 $667 62 .22? INVENTOR I June 1, 1943. NY 2,320,603

DRAFTING INSTRUMENT Filed Aug. 29, 1942 2 Sheets-Sheet 2 all,

(/2662? Tfyy MENTOR Patented June 1,1943

' UNITED STATES PATENT OFFICE Jessie Tllvy, Seattle, Wash. I Application August 29, No. 456,685 7 4 Claims.

My invention relates to the drawing or outlining of geometrical figures oi! predetermined contours, and has among its objects and advantages the provision of an improved drawing instrument for reproducing such figures in variable proportions.

In the accompanying drawings:

Figure 1 is a face view of the instrument;

Figure 2 is a side view; I

Figure 3 is a top plan view with portions oi the supporting legs broken away;

Figure 4 is an enlarged sectional view along the line 4--4 of Figure 2;

Figure 5 is an'enlarged sectional view along the line 55 of Figure 2;

Figure 6 is a sectional view along the line 6-6 of Figure 3';

Figure '7 is a sectional view along the line 'l---'! of Figure 3; l I

figure 8 is a cross sectional view of a pattern element which guides the instrument to draw a figure of predetermined contour;

xFig'ure 9 is a sectional view of an inscribing rod;

Figure 10 is a fragmentary view of an extension for the inscribing rod;

Figure 11 is a fragmentary sectional view of a leg extension; and

'Figure 12 is a sectional view of a diameter increasing sleeve insertable over the inscribing rod for coaction with the pattern element to reduce the size of the outline being inscribed;

In the embodiment selected for illustration, I make use of a head 16 to which is secured three supporting legs i2, i4 and [6. These legs are arranged in diverging relationship and each in-. cludes a threaded shank i8 threaded into a bore 26 in the bottom face of the head 16. Each leg is also provided with a fixation pin 22 at its lower end 'ior engagement with the drawing surface 24 to support the instrument against accidental shifting.

Depending from the cradle I6 is an inscriber rod 26 comprising sections 28 and 36. Section 36 is provided with a threaded shank 32 threadedly engageable in a threaded bore 34 in the section 26. To the lower end of the section 36 is connected a chuck 36 which carries the inscribing point 36 for engagement with the drawing surface 24. In Figure 9, the section 36 is provided with a bore 46 within which is mounted a compression spring 42, one end of the spring abutting the bottom wall of the bore and the other end abutting a flange 44 on the inner end or a small rod 46 to which the chuck 36 is connected. A

' contoured outlines.

Washer 46 is threaded into the lower end of the section 66 for slidably guiding the rod 46. In cases where a relatively long inscriber rod is required, particularly when outlining large patterns, an extension rod 66 is interposed in the inscribed rod 26. This extension rod includes a shank 62 threadedly engageable. in'the bore 24 and a threaded bore 64 for connection with the.

shank l2.

The inscriber rod 26 is connected with the head i6 for universal movement. A ball 66 is formed at the upper end of the section 26, which ball is rotatably housed in a tapered neck 66 formed on one end of a sleeve 66 threaded into a bore 62 in the head i6.

. Head I6 is provided with a vertical T slot 64 within which is slidabl mounted a correspond-- ingly shaped scale rule 66. The scale rule is supported at right angles to the drawing surface 24 and lies substantially in the plane oi the supporting legs I2 and ,I4. Means for adiustably securing the scale rule 66 in selected. operating positions comprises a screw 66 having a square head 16 lying in a correspondingly shaped recess I2 in the head I6. The recess 12 is deeper than the thickness of the head 16 and is so arranged as to bring the rear face of the scale rule 66 into engagement with the head I6, so that the scale rule may be fixedly secured through tightening of the nut 14.

To the lower end of the scale rule 66 is secured a cradle 16 within which is mounted a formed on the key 86 and extends into a correspondingly shaped recess 92 in the pattern element 18. A tapered recess 94 is formed on the peripheral face of the pattern element 18 diametrically opposite the recess 62 for the reception of the tapered end 96 of a screw 98. Thus the key 86- restrains the pattern element" from accidental rotation, while the screw 98 clamps the pattern element in a fixed position between the two pointed ends 66 and 66.

On the flat wall I66 01' the cradle 16 is sea scale plate I02 also bored Iul the pass ing of the shaft 82. A pointer I is keyed to the shaft 02 and is held on the shaft against the plate I02 by a head I06 formed on a screw I08 threaded into the shaft '2. A knob llil comprising a nut is mounted ona screw 2 extending through a slot I ll in the scale plate I02, which slot is concentrically arranged with respect to the axis of the shaft 22. The wall lllii is provided with a curved groove H8 for accommodating the head Ill on the screw 2. Thus the pointer I may be rotated about the axis of the shaft 82, and the scale plate I02 is provided with a scale I across which the end of the pointer I04 sweeps to indicate the various angular positions of the pattern element II. The zero position of the scale is indicated at I22, so that the pattern element ll will lie in a horizontal plane in parallelism with the drawing surface 2 when the pointer I registers with the portions of the outlines when employing the zero position on the scale I20. Since the key l6 restrains the pattern element from rotation relatively to the shaft .2, rotation of the pointer I imparts corresponding rotation to the pattern element.

On the front face of the scale rule 66 is provided two scales I24 and I26 respectively associated with pointers I28 and I30 formed on the head III.

In operation, a series of pattern elements It I.

is employed, each pattern element having an opening of predetermined contour. Inreproducing geometrical contours lying in a plane paralleling the drawing surface 24, the pointer IN is moved to zero position and firmly latched by tightening the head or nut H0, When drawing the pattern, the instrument is held firmly by placing one hand on the head It and grasping the rod 48 and lifting the chuck end off the drawing surface. The inscriber rod 26 is then pivoted to a position at rest against the pattern element 78. The chuck end 26 is then brought into engagement with the drawing surface and the inscriber rod is moved in a path determined by the outline of the opening 80 for reproducing a correspondingly shaped figure on the drawing surface. The rod 46 is spring tensioned so that its chuck end 26 is held in proper pressure relationship with the drawing surface.

In reproducing pattern outlines lying in a predetermined angle to the horizontal, the pointer I is swung to the right or the left and to the desired degree mark on the scale i2, depending upon the direction of angle desired, after which the pointer is made secure and the inscriber rod 28 manipulated in the same manner as when outlining horizontal outlines. With a given set of pattern elements 18, each pattern may be reproduced in a large range of selected proportions, depending upon the vertical distance between the pattern element and the drawing surface 24. In outlining relatively small patterns, a sleeve I32 is slipped over the inscriber rod 26 to lie within the opening 8., thereby increasing the diameter of the inscriber rod so as to produce a smaller outline.

I In reproducing patterns of relatively large outline, each of the legs i2, II and I6 is provided with an extension I34, which extension is proshort legs, while the scale I2. is employed when using the leg extensions. The sleeve I82 is employed only when reproducing pattern outlines less than one inch in diameter for maximum length. The leg II is provided with a pivoted pointer 2 which may be employed in certain types of drawing where it is desirable to locate the instrument on a predetermined line located at right angles to a second predetermined line on which the fixation points of the legs l2 and H are located.

Without further elaboration, the foregoing will so fully illustrate my invention, that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

I claim:

1. A drafting instrument comprising a head having supporting legs, an inscribing rod depending from said head, a universal connection between the upper end of the inscribing rod and said head, a pattern contour guide located to engage the inscribing rod intermediate its ends to control its inscribing movement, extensions for said legs, and means for varying the size of theinscribing rod at its point of engagement with the pattern contour guide to vary the size of the pattern reproduced by the inscribing rod.

2. A drafting instrument comprising a head having supporting legs, an inscribing rod having a universal connection with said head. a pattern contour guide located to engage the inscribing rod intermediate its ends to control its inscribing movement, a cradle fixedly related to said head, and pivot means on said cradle supporting said pattern contour guide for pivotal movement about a horizontal axis.

3. A drafting instrument comprising a headhaving supporting legs, an inscribing rod having a universal connection with said head, a pattern contour guide located to engage the inscribing rod intermediate its ends to control its inscribing movement, a ruler member slidably mounted on said head for vertical movement, a cradle attached to said ruler member, and first and second pivot means carried by said cradle for supporting said pattern contour guide for movement about a horizontal axis, said first pivot means being threadedly connected with said cradle and adjustable for loosely or fixedly sup-V porting the pattern contour guide.

4. The invention described in claim 3 wherein said cradle is provided with a scale, and a pointer attached to said second pivot means coacting with said scale to denote the angular position of said pattern contour guide.

JESSIE T. IVY.

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