US2632953A

US2632953A - Ellipsoidal compass

Info

Publication number: US2632953A
Application number: US143639A
Authority: US
Inventors: Robert S Kafka
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-02-11
Filing date: 1950-02-11
Publication date: 1953-03-31
Anticipated expiration: 1970-03-31

Description

March 31, 1953 KAFKA 2,632,953

ELLIPSOIDAL COMPASS Filed Feb. 11, 1950 IN VEN TOR. ROBERT S. KAFKA ATTORNEY Patented Mar. 31, 1953 UNITED STATES PATENT OFFICE ELLIPSOIDAL COMPASS Robert s. Kafka, Woodside, N. Y.

Application February 11, 1950, Serial No. 143,639

3 Claims.

This invention relates to an ellipsoidal compass.

It is an object of the invention to make a compass that will draw ellipses. Another object is to make a compass that will draw ellipses of diner-entratios of longitudinal to transverse axis, being of infinite adjustability from aperfect circle to an ellipse of very large axial ratio.

The objects of the invention are accomplished, generally speaking, by an ellipsoidal compass having legs connected by a frame pivotally and rotatably mounted on one leg and pivotally and slidably mounted on the other leg.

The above and further objects and novel features of the present invention will more fully appear from the following detailed description when th same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of llustration only and are not in tended as a definition of the limits of the invention, reference for this latter purpose being bad primarily to the appended claims.

In the drawings, wherein like reference characters refer to like parts throughout the several views:

Figure 1 is a side elevational view of an ellipsoidal compass;

Figure 2 is a section on line 2-2 of Figure 1;

Figure 3 is a section on line 3-3 of Figure 2;

Figure 4 is a plan view of a modified form of the invention, partly in section; and,

Figure 5 is a section through Figure 4 on line 5-5.

In the figures, the numeral l4 indicates the center leg of the compass 0, the term center leg indicating the leg which serves as a pivot about which the other turns. This leg is provided at the end with a needle 11 and at the top with a fixed grip 13. The leg is oifset at l4-I5 and the offset portion is formed in the shape of a ball bearing 44, the center of which is on the axis of the leg and of pin H. The upper portion 12 of the center leg constitutes a shaft which serves to support a block II which is slidably mounted thereon. A coil spring 48 bears at its end against the top of block H and the bottom of grip l3. The sides of the block I l are flattend above and below ledges 54, the part below this ledge being reduced by the width of a frame or guide is which is of U-shape and firmly and rigidly connected at its ends 2! to the revolving leg 22 of the compass. The block H has a snug but sliding fit between the arms of the U-shaped guide 18, which is connected to the portions of the block H above the ledge 54 by parallel motion means,

2 which are shown in this instance as four straps I9 pivoted at their upper ends to the block and at their lower ends to the frame by pivot pins 28.

By this construction, the center leg may move up and down through the block ll against the pressure of the spring 48, an upper limit of mo tion being established by a. limit stop on the upper end of part M- of the leg, and back and forth parallel to the revolvable leg as permitted by the parallel motion of the straps l9.

Rigidly fixed at the ends of the U-shaped frame I3 is the revolving leg 22 which is provided with a guide 24, extending along the inner side thereof, formed by slots in opposite sides of the leg; The leg has two parts, the outer and longer of which, 23, is pivoted to that portion which is firmly affixed to the frame 18, enabling the draftsman to adjust the position of his lead without altering the basic setting of instrument. This outer part holds lead 28 in the usual grip 27.

A frame 32-33 is pivotally and slidably mounted on the guide by means of slider 29. slider has a, socket 3 9 which receives a ball 3| on the frame part 32. The sides of the socket 30 are extended far enough to bear upon the shank that connects the ball to the frame, leaving a slot that is parallel to the leg and permitting the slider to move along the guide 24 without cramping, but preventing side play.

The frame part 32 is a yoke slidably mounted between the plates 33-34 of the frame part 33. The lateral tension upon the yoke may be varied by a slider 45 and a cam pressure member 46, eliminating all side play as the

plates

33, 34 eliminate all vertical play. The member 33 (or 34) has blocks that engage the sides of the yoke and permit it to move only in a straight and unwavering line. The yoke may be manually moved between plates 33-34 and retains its position after being moved.

A block 39 is immovably fixed between the plates 33-34 and is provided with a bearing opening that snugly engages a bearing sleeve 35. being revolvable about the sleeve and held from motion along it by the pressed on bushing 35 and The sleeve is provided with cut away parts which permit it to tilt about a pivot pin 40 fixedly mounted in a ball bearing44 formed in the part of leg it between offsets I4-l5. A set screw 4| prevents the pin 49 from moving freely.

By this means the frame may be placed at right angles or at an acute angle to the axis of the center leg. The offset parts i4-l5 engage diagonally opposed parts of the sleeve 36 as an abutment when the frame 3233 is at right angles to the leg. The position of the two legs with respect to each other can be altered by moving the yoke through the gripping plates, without changing the character of the curve that will be drawn by the instrument, but only its size. The shape of the ellipse is altered by altering the angular relation of the frame to the center leg, by tilting about pivot 49.

The operation of the instrumentis based upon the observation that the projection of a circle which is at an acute angle to the axis of projection is an ellipse. Thus, if one takes a coin and looks squarely at it, it appears circular, but if it be tilted somewhat about a diameter it loses its circular appearance and becomes elliptical. This instrument makes use of that prim ciple. The sleeve 36 on the ball 43 is a circle about which bearing 39 in the connection 3 can revolve. The sleeve can tilt about the pin 40, and the frame tilts withit. When viewed from above in position normal to the axis ofthe leg its projection is circular, but when tilted its projection is an ellipse and any object which compelled to follow the, circumference of the sleeve 35 will travel in an elliptical path corresponding to the. projection and directly related to the angle between the axis ofthe socket and the axis oi the center leg. By adjusting the yoke 32-33 between the plates a series of ellipses can be drawn concentrically and in parallel, differing in size alone. By adjusting the plane of the connection 32-33 with respect to the axis of the center leg the shape of the ellipse is altered. When the connecting frame is normal to the center leg the compass draws a true circle. When the angle is altered slightly the figure departs slightly from the circularposition, becoming slightly elliptical. ihe figure drawn becomes increasingly elliptical as the angle of the frame to the center leg increases. The center leg automatically adjusts itself to the proper length for cooperation with the revolving leg, a worthwhile advantage.

In Figures 4 and 5, the center leg BI is screw threaded at 65. A nut 62 is screwed up to the limit of the thread and this nut is provided with recessed, diametricall positioned, half bearings in which the pins 10 of a ring 56 are seated. A washer 63 having opposed half bearings is engaged with the pin '10 and a nut Eli is screwed on the thread 55 and holds the parts in position. The ring is cut awe-3 to pcrnnt it to he tilted about the pins Hi. A circular frame or annulus 6'! is held about the ring it by upper and lower plates B869. The

frame

61, 68, 69 can thus turn around the ring 65 and may be connected to the revolvable leg of the compass byv bearing 3| which fits the slider 29 as hereinabove described.

As many apparently widely diiferent embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments.

What is claimed is:

1. An ellipsoidal compass having a center leg and a single revolving leg, parallel motion means connecting the revolving leg the center leg, said means comprising two parallel links having pivotal axes perpendicular to the plane ontaining the longitudinal axes of said legs, a slider movable along the revolving leg and having a ball socket slotted parallel to the center leg, a frame having a ball connection with said socket and a shank guided by the slot, a circular bearing tiltably mounted on a pivot on and normal to the axis of the center leg, and a circular bearing on theframel'engaging the said first-mentioned circular bearing, permitting angular adjustment of the frame on the center leg.

2. An ellipsoidal compass having a center leg and a. single revolving leg, guide means rigidly connected to said revolving leg and movable transversely relative to said center leg, parallel motion means connecting the revolving leg to the center leg, said parallel motion means comprising two parallel links pivotally mounted on said center leg and said guide means, the pivotal axes of said links being perpendicular to the plane containing the longitudinal axes of said legs, a slider movable along the revolving leg and having a ball socket slotted parallel to the center leg, a frame having a ball connection with said socket and a shank engaged by the sides of the slot, and a ring tiltably mounted on the center leg, said frame having slidable and rotatable connection with said ring and said revolving leg being rotatable with the frame.

3. A11 ellipsoidal compass having a center. leg and a single revolving leg, guide means rigidly connected to said revolving leg and movable transversely relative to said center leg, parallel motion means connecting the revolving leg to the center leg, said parallel motion means compris ing two parallel links pivotally mounted on said center leg and said guide means, the pivotal axes of said links being perpendicular to the plane containing the longitudinal axes of said legs, a slider movable along the revolving leg and having a ball socket slotted parallel to the center leg, a frame having a call connection with said socket and a shank guided by the slot, 2. circular bearing tiltably mounted on a pivot normal to the center leg, a circular bearing on the frame engaging the said circular bearing, permitting angular adjustment of the frame on the leg, said revolving leg being comprised of a part connected to the slider and a pivoted part having means to support writing means.

ROBERT s. KAFKA.

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

STATES PATENTS Number. Name Date 715,883 Sherman T Dec. 16, 1905 1,406,3 3 Hoffman et al. Feb. 14, 1922 2,493,229 Dibrell Jan. 3, 1950 FOREIGN PATENTS Number Country Date 70,680 Germany Aug. 31, 1893 M3266 Austria Oct. 25, 1935 325,095 Germany Sept. 10, 1920 136,830 Great Britain Oct. 18, 1935