US2906057A

US2906057A - Toy top

Info

Publication number: US2906057A
Application number: US630497A
Authority: US
Inventors: Miles V Sullivan
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-12-26
Filing date: 1956-12-26
Publication date: 1959-09-29
Anticipated expiration: 1976-09-29

Description

Sept 29, 1959 M. v. SULLIVAN TOY TOP Filed Dec. 26, 1956 FIG. 5'

@ allr lNl/ENTOR By MILES K SULL/VA/V Haw FIG. 7

ATTORNEY TOY TOP Miles V. Sullivan, Summit, NJ.

Application December 26, 1956, Serial No. 630,497

1 Claim. (Cl. 46-64) This invention relates to toy tops and more particularly to a toy top of the self-inverting type which when spun in an upright position may be made to automatically invert and spin upon its handle.

One type of top of the above general class has heretofore been constructed with uneven weight distribution with respect to the vertical axis of the body of the top. This uneven weight distribution is created by diametrically opposite weighted portions located between the handle and horizontal median line and between said median line and the pivot point of the top, respectively. It is claimed that these diametrically opposite weighted portions exert centrifugual forces in the opposite directions upon the upper and lower portions of the top, when the top is spun rapidly in an upright position, to cause the top to turn over or invert and spin upon its handle. When this type of top is spun slowly or slower than a critical speed, these centrifugual forces are insuflicient to cause the top to turn over or invert and it will remain spinning in an upright position in the conventional manner. Because it is dilficult to attain the exact critical speed of rotation required for turnover, it is necessary to spin the top at a rate much greater than this critical speed when turnover is desired and at a rate much slower than this critical speed when turnover is not desired. Because there is such a marked difference between these two speeds of rotation, this top has a definite disadvantage in that the secret of the operators control over turnover is readily apparent to an observer.

A second type of top of the above general class has heretofore been constructed that does not depend upon an uneven weight distribution with respect to its vertical axis to accomplish automatic turnover. The lower portion of the body of this type of top is substantially spherical in shape and the force acting to cause the top to invert and spin upon its handle involves an interaction of a frictional drag near the point of contact of the spherical portion of the body of the top and the surface upon which it is spun and a precessional torque which is an interaction between the torque produced by gravitational force and angular momentum. This second type of top also has a critical speed of rotation required for turnover, that being the speed at which the required frictional drag and precessional torque are produced. This top also suffers the same disadvantage as the first top described above in that the secret of the operators control of turnover is readily apparent to an observer.

Thus, with either of the tops described above an observer may predict whether the top will spin in an upright position or whether it will turn over and spin upon the handle by observing the original speed at which the top is spun.

An object of the present invention is the provision of a toy top of the self-inverting type in which the secret of the operators control over turnover is not readily apparent to an observer.

A further object of the present invention is the provision of a toy top of the self-inverting type which,

aired States Patent under the exclusive control of the operator, may be made to spin in an upright position in the conventional manner or made to turn over and spin upon its handle without altering the speed at which the top is originally spun.

An additional object of the present invention is the provision of a toy top of the above-described type with which the owner and operator may mystify and amaze observers by exercising exclusive power over the top tocause it to spin in an upright position or to cause it to invert and spin upon its handle.

A still further object of the present invention is the provision of a toy top of the second general type described above which regardless of the speed at which it is spun can be prevented from turning over and spinning upon its handle.

An additional object of the present invention is the provision of a top of the second general type described above which when made to invert and spin upon its handle will spin there with greater stability.

A still further object of the present invention is the provision of a toy top of the general type described above which is simple in construction, economical to manufacture and which is sturdy and capable of withstanding substantial abuse.

In accordance with one aspect of the present invention, 1 have determined that control of turnover of a self-inverting top of the second type described above may be accomplished by controlling the frictional drag exerted on such a top by the surface upon which it is spun and, accordingly, the speed of rotation of such a top is immaterial as long as it is spun at a speed above its critical value, i.e., the speed required for turnover. Furthermore, it is not necessary to eliminate friction entirely in order to attain this control over turnover as it is only necessary to lower it to a point where the interaction of its force with the precessional torque is insufiicient to cause the top to invert or turn over.

Accordingly, a feature of the present invention relates to controlling the frictional drag exerted on a self-inverting top by the surface upon which it is spun.

More specifically in accordance with this aspect of the present invention, the required control over frictional drag in a top of the above-described type may readily be accomplished by changing the shape of that portion of the top which is in contact with the surface upon which the top is spun. In particular, it is sufiicient to provide a small area at the bottom of the top whose radius of curvature is small with respect to the radius of curvature of the main body of the top. This is advantageously a pivot on which the top can spin with very little frictional drag.

Accordingly, another feature of the present invention relates to the changing of the radius of curvature of that portion of a top which contacts a horizontal surface upon which it is spun.

An additional feature of the present invention relates to outwardly extending a pivot, having a relatively small radius of curvature, from the spherical portion of the body of a top of-the self-inverting type described above and for retracting this pivot within the body of the top.

In accordance with another aspect of the present invention, it is advantageous to be able to control the turnover of a self-inverting top of the type described above in a secretive and unobvious manner so as to enable the owner thereof to astound and amaze observers by ostensibly exercising complete power over the turn over of the top.

Accordingly, a further feature of the present invention relates to outwardly extending a pivot from the spherical portion of the body of a top and for retracting this pivot within the body of the top in an unobvious manner, thus selectively altering the radius of curvature of that portion of a top which contacts a horizontal surface upon which it is spun.

In accordance with still another aspect of the present invention, I have determined that a self-inverting top of the type which depends upon the frictional drag and precessional torque for turnover will spin upon its handle when in its inverted position with greater stability if the end of the handle is convexly curved. Heretofore, such tops have been constructed with a cylindrical handle having a flat face upon which the top spins when it is inverted.

Accordingly, an additional feature of the present invention relates to a handle in a self-inverting top of the second type described above having a convexly curved end upon which to spin when in an inverted position.

The above and other objectsand features of the present invention may be more readily understood from the following description of three specific illustrative embodiments thereof when read with reference to the attached drawing in which:

Fig. 1 is an unassembled axial sectional view of the body and handle of one illustrative embodiment of the self-inverting top of the present invention;

Fig. 2 is an assembled axial sectional view of the body and a side elevation view of the handle of the top illustrated in Fig. 1 showing the position of the pivot when retracted;

Fig. 3 is a partial side elevation view of the body of the assembled top illustrated in Fig. 2 showing the position of the pivot when extended;

Fig. 4 is an assembled axial sectional View of the body and a side elevation view of the slidable pivot pin and the cap therefor of a second illustrative embodiment of the self-inverting top of the present invention;

Fig. 5 is a horizontal sectional view taken on line 55 of Fig. 4;

Fig. 6 is an axial sectional view of the body and side elevation view of the pivot pin of the top illustrated in Fig. 4 showing the manner in which the pivot pin is inserted into the body; and

Fig. 7 is an assembled axial sectional view of the body and side elevation view of the pivot pin of a third illustrative embodiment of the self-inverting top of the present invention.

The illustrative embodiment of the self-inverting top of the present invention shown in Figs. 1, 2 and 3 of the drawing comprises two separate parts, body 1 and handle 2 which are assembled by screwing handle 2 into body 1. As shown, body 1 is substantially globular in form with a relatively deep and diametrically wide cylindrical recess 3 formed therein. In line with the longitudinal axis of recess 3 and at the bottom thereof, threaded hole 4 is provided which has an unthreaded relatively small diameter hole 5 extending through the spherical surface of body 1. Recess 3 extends downwardly in body 1 to a point such that the center of gravity of the assembled top is spaced slightly below the geometrical center of body 1 to permit the top, when at rest, to as some the position shown in Pig. 2.

Handle 2 is cylindrical in form and has a knob portion projecting out of recess 3 in body 1 adapted to be used for spinning the top, a smaller diameter threaded portion 7 adapted to be screwed into threaded hole 4 in body 1 and a relatively small diameter pivot 8 adapted to extend through hole 5 in body 1 to contact a horizontal surface upon which the top is spun. End surface 9 of handle 2 as shown in Fig. 2 is convexly curved to stabilize the spinning of the top when it is inverted and spinning upon this surface. The radius of curvature of surface 9 is, however, not critical and may vary substantially from that shown in Fig. 1. The length of the knob portion of handle 2 is such that when handle 2 is threaded into body 1, the knob portion will project above body 1 in a radial direction to a pointwhich permits easy graspingb'et'w'een the thumb and forefinger or second finger by which the top may besp un. The length of pivot 8 is such that when threaded portion 7 of handle 2 is screwed into threaded hole 4 in body 1 until shoulder 6 contacts the bottom of recess 3, pivot 8 will extend through hole 5 a relatively small distance past the spherical surface of body 1. This distance may, for example, be of the order of one sixty-fourth of an inch. The diameter of pivot 8 is relatively small and may, for example, be of the order of one sixteenth of an inch. The radius of curvature of the lower end of pivot 8 is small as compared to the radius of curvature of body 1.

When body 1 and handle 2 are assembled and the top is spun upon a horizontal surface with pivot 8 retracted into body 1 as shown in Fig. 2, the interaction of frictional drag and precessional torque, the latter of which results from gravitational force and angular momentum, will cause the end of handle 2 at surface 9 to swirl through larger and larger circles until surface 9 of handle 2 contacts the surface upon which the top was spun whereupon the top will raise itself upon surface 9 and spin therein in an inverted position. When the top loses speed, it will right itself again and come to rest in the position shown in Fig. 2.

When the top is spun upon a surface with pivot 8 extended in hole 5 through the surface of body 1 as shown in Fig. 3, the reduction in the friction between the spinning top and the surface caused by the smaller area of pivot 8 in contact therewith will reduce the force of the frictional drag exerted on the top to a point where this force interacting with the precessional torque will be insufficient to cause the top to turn over.

In the operation of the illustrative embodiment of the top shown in Figs. 1, 2 and 3, the owner has positive control over the turnover of the top and may determine whether the top will turn over or not when spun. This control is exercised by screwing handle 2 either clockwise or counterclockwise a part of a turn to extend or retract, respectively, pivot 8. This may be done while the top is hidden from view of observers, for example, while the top is in the palm of the hand, and in this manner the appearance is given that the owner has magical power over the top.

The illustrative embodiment of the top shown in Figs. 1, 2 and 3 may be constructed of wood, metal, plastic or any other suitable material. In a preferred form, body 1 and handle 2 may be of plastic and constructed by two separate and simple molding operations after which the top is assembled by screwing handle 2 into body 1. The friction exerted by the threads and sidewalls of threaded hole 4 against the threads and surface of threaded portion 7 of handle 2 is such that the setting of pivot 8, either extended or retracted, will not be altered by the torque applied to the knob portion of handle 2 when the top is spun.

A second illustrative embodiment of the self-inverting top of the present invention is shown in Figs. 4, 5 and 6. This embodiment is similar to the first embodiment described above in appearance and overall dimensions and differs only in the manner in which the pivot is extended and retracted. As shown in Fig. 4, this embodiment comprises three parts, body 11 with an integral peg 14, slidable pivot pin 12 extending therethrough and cap 22 for pivot pin 12. Body 11 is substantially globular in form with a relatively deep and diametrically wide recess 13 and an integral peg 14 extending from the bottom of recess 13 along the longitudinal axis thereof to a point beyond the circumference of the body. Extending on the longitudinal axis of peg 14 from the top thereof on through the spherical surface of body 11 is a small diameter hole 15 having a larger diameter portion forming a small cylindrical cavity 16 in peg 14 as shown in Fig. 4. The upper portion of peg 14 from point 17 to the top thereof is split by a narrow transverse slot 18 through the axis'of peg 14, thus forming two leg portions joined at point 17.

As shown in Figs. 4 and 6, pivot pin 12 comprises a small diameter portion 19 adapted to slide in hole 15 of body 11 and extend a small distance through the spherical surface of body 11, a stop 20 adapted to fit into cavity 16 in peg 14 to limit the movement of pin 12 to the extent of the clearance between the top and bottom of stop 20 and the upper and lower surfaces of cavity 16 and a portion 21 having a slightly larger diameter than portion 19 and adapted to receive a frictional force from the cylindrical surface of hole 15 between the two leg members of peg 14.

Cap 22 is installed on pivot pin 12 after the pin is inserted into hole 15 of body 11 in the manner to be described below. As shown in Fig. 4, cap 22 has an apron 23 adapted to slidably fit over the end of peg 14 to cover the spacing between the top of peg 14 and the bottom of cap 22.

The length of portion 19 of pivot pin 12 is such that when cap 22 of the assembled top is depressed until the bottom of stop 20 contacts the lower surface of cavity 16, portion 19 of pivot pin 12 will extend through hole 15 in body 11 a relatively small distance past the spherical surface of body 11 to provide a pivot upon which the top may be spun when turnover is not desired. The clearance between the top and bottom of stop 20 and the upper and lower surfaces of cavity 16 is such that when pivot pin 12 is moved upward until the top of stop 20 contacts the upper surface of cavity 16, portion 19 of pivot pin 12 will be retracted entirely within hole 15 in body 11 and when the top is spun on the spherical surface of body 11 it will invert and spin upon cap 22.

The radius of curvature of the lower end of portion 19 of pivot pin 12 which when extended contacts the surface upon which the top is spun is small as compared to the radius of curvature of body 11. The upper surface of cap 22 upon which the top spins when inverted is convexly curved to stabilize the spinning of the top in the inverted position.

The illustrative embodiment of the top shown in Figs. 4, 5 and 6 may be constructed of wood, metal, plastic or any other suitable material. In a preferred form, body 11, pivot pin 12 and cap 22 are made of plastic by separate and simple molding operations. Pivot pin 12 is inserted into body 11 in the manner shown in Fig. 6. As shown in Fig. 6, the two leg members of peg 14 are separated to permit removal of the mold which formed hole 15 and cavity 16 in peg 14 and while separated pivot pin 12 is inserted. After pivot pin 12 is inserted in hole 15 of body 11, cap 22 is then installed on pivot pin 12 by cementing or by any other suitable means. As a result of the transverse slot in peg 14 and through the molding of body 11 of the top, the two leg members of peg 14 exert a spring action toward each other such that when pivot pin 12 is inserted in hole 15 as shown in Fig. 4, the two leg members of peg 14 will exert a frictional force upon portion 21 of pivot pin 12. This force is such that the setting of pivot pin 12 either extended or retracted will not be altered by the torque applied to peg 14 and cap 22 when the top is spun.

Apron 23 of cap 22 covers the gap between the top surface of peg 14 and the bottom of cap 22 when pivot pin 12 is in a retracted position and thus gives the appearance that peg 14 and cap 22 are one integral part.

The embodiment of the top of the present invention shown in Figs. 4, 5 and 6 and described above operates in the same manner as the first embodiment shown in Figs. 1, 2 and 3. When portion 19 of pivot pin 12 is extended out of body 11, the top will not invert regardless of the speed at which it is spun. When portion 19 of pivot pin 12 is retracted within body 11 and the top is spun upon the spherical surface of body 11, the top will invert and spin upon cap 22.

A third illustrative embodiment of the self-inverting top of the present invention is shown in Fig. 7. This embodiment is a modification of that shown in Figs. 4, 5 and 6 and is similar in appearance and overall dimension. The body 51 with recess 53 and peg 54 having hole 55 and cavity 56 is formed in two pieces by two separate molding operations. Slidable pivot pin 52 with attached spring members 57 and cap 58 with apron 59 is placed in one half of the top and the other half is then press fitted or cemented in place. Spring members 57 in addition to providing a frictional force against the outer walls of cavity 56 provide a stop which limits the extension and retraction of pivot pin 52 in hole 55 of body 51.

The embodiment of the top shown in Fig. 7 operates in the same manner as the first two embodiments described above. When a downward force is applied to cap 58, pivot pin 52 will be extended out of hole 55 in body 51 a short distance, the extension being limited when the bottom of spring members 57 contact the lower surface of cavity 56. Regardless of the speed at which the top is spun with pivot pin 52 extended, the top will not invert or turn over. When pivot pin 52 is retracted within hole 55 until the top of spring members 57 contact the upper surface of cavity 56 and the top is spun on the spherical surface of body 51, the top will invert and spin upon cap 58 of pivot pin 52.

It is to be understood that control of frictional drag in a top of the self-inverting type in accordance with the present invention is not limited to the utilization of a retractable pivot to alter the radius of curvature of that portion of the top which contacts the surface upon which the top is spun. Other arrangements for altering the radius of curvature of the top and, hence, attain control over turnover are within the scope of the present invention. For example, control over turnover in this type of top may be accomplished by providing the top with a flexible bottom and means for selectively distorting the bottom to alter the radius of curvature.

It is to be understood that the three embodiments of the present invention described above are illustrative of the application of the principles of the invention. Numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

A toy top of the self-inverting type comprising in combination, a body substantially globular in form and having a relatively wide and deep cylindrical recess formed therein, said body having a threaded hole in the bottom of said recess axial therewith and a small diameter through hole from the bottom of said threaded hole and axial therewith through the globular surface of said body, a cylindrical top handle having a smaller diameter threaded end portion adapted to be screwed into said threaded hole, said handle projecting centrally out of said recess in said body along the longitudinal axis thereof to provide a knob with which to spin said top, a relatively small pivot on the threaded end portion of said handle, said pivot adapted to be fully extended from and fully retracted into said through hole in said body in response to a fraction of a turn of said handle with respect to said body.

References Cited in the file of this patent FOREIGN PATENTS 413,525 Great Britain July 19, 1934 889,574 Germany Sept. 10, 1953 1,033,037 France Apr. 1, 1953 1,119,682 France Apr. 9, 1956