Rotating or spinning tops are well known. Conventional tops are typically symmetrical and spin rapidly about their symmetrical axis, also referred to as the spin axis. The top typically spins at a lean relative the vertical. The amount of lean is referred to as the precession angle. When the bottom point of the top is substantially fixed in position relative to the surface or table, the top will move about the vertical axis and sweep out a cone-shaped area as a result of this lean. This motion is called precession. When the bottom point is allowed to move or travel, the spin and precession of the top causes the top to move across the supporting surface.
The characteristic movement of a top can be traced if the bottom point is constructed to leave a legible trail. The general concept of forming a top using a writing instrument as the bottom point is not new. Many toy tops use this principle to provide amusement to the user by producing a graphic of the path of the top. For example, the prior art contains many examples of toy tops having writing points. This general concept is taught in U.S. Pat. No. 2,618,891 which uses a ball point pen top, U.S. Pat. No. 3,025,632 for an amusement apparatus and U.S. Pat. No. 3,861,077 which uses a pencil or ball point pen as part of the top.
To facilitate a legible mark traced by the top, prior art devices commonly use a ball point pen structure. Tops rotating upon ball points trace a resulting path which may be described as a chain of interconnected loops. Ball points, due to the roller surface, cannot directly transfer all the top's rotational and precession forces to the supporting surface. Writing tops using ball point pens do not naturally precess, as the precession phenomena of rapidly rotating tops is traditionally observed, due to the ball point's natural tendency to roll with respect to the writing surface. A ball point top tends to wander and fall over as the top acquires a precession angle sufficient to cause the roller point to roll out from under the axis of spin.
Writing tops have not been limited to ball point writing tips, however. Alternative tips on writing tops have been used. For example, lead pencils and chalk tips have been used to more accurately trace a top's full precession. These types of instruments are unfavorable because they require a top with excessive weight to provide the necessary force to cause the lead or chalk to inscribe the writing surface. Therefore, there are disadvantages associated with the use of ball points or pencil lead writing tops. To provide a writing top which can be inexpensively produced, however, conventional and low cost writing devices must be employed.
Soft porous tipped writing instruments are known and can be inexpensively produced. Typical soft porous tips, sometimes referred to as "felt" tip pens, have a fibrous nib which includes a writing tip and a shaft. The shaft is in communication with an ink reservoir. The ink reservoir contains a supply of liquid ink which is absorbed into the nib and thereby feeds ink to the writing point. When the ink laden writing point is placed in contact with a writing surface such as paper, the ink flows onto the writing surface leaving a mark. Due to this free flow of ink, however, if there is no relative movement between the writing tip and the writing surface, the ink may continue to flow onto the writing surface and create an undesirable blot or spot at the point of contact with the paper or surface.
Discovery
A soft porous tip writing instrument has an interesting and unique feature which distinguishes it over alternative writing devices, especially ball point pens. The present inventors have discovered that when a soft porous tip pen is inclined at an angle on a writing surface and rotated, writing also occurs. The reader may easily demonstrate this effect.
Place a piece of paper on a smooth surface. The paper and the surface should have a relatively low coefficient friction so that the paper readily slides relative to the supporting surface. Then position the writing point of a soft porous tip pen on the paper at an angle of inclination. The pen may have a point or may be of a squared, rounded or angled shape. While holding the pen in a stationary location relative to the surface supporting the paper, rotate the pen along its longitudinal axis.
Two effects will be observed.
First, the paper will slowly rotate propelled by the friction of the soft porous tip as it is rotated. Second, the soft porous tip pen at its point will gradually trace a path--a spiral path--on the paper as the paper slowly rotates. Neither ball point pens nor pencils offer this unique characteristic.
In the disclosure that follows, I use the characteristic spiral pattern that I have discovered with respect to a rotating soft porous tip pen to interact with the natural forces of precession existing when a top rapidly spins. As a result, I obtain a unique spiral pattern not achieved by prior art tops having writing tips. There results beautiful, almost three dimensional traced pattern by the toy top of my invention. The spiral produced will always be unique, never exactly duplicated. My invention combines a soft porous tip writing instrument with a conical shaped top body portion to provide a device which can be adjusted.