Amusement Device Employing Dilatant Suspension Filler

Abstract

An amusement device or toy comprised of an impervious elastic container in a desired configuration and a dilatant suspension enclosed therein whereby jabbing, squeezing or pulling the same creates unusual distortions, recovery and flow properties which are not only fascinating but also enhance human tactile and kinesthetic perception of materials.

Description

This invention relates to psychorheological devices comprised of a dilatant suspension enclosed in an impervious elastically deformable container whose primary object is to amuse young and old alike and to enhance human tactile and kinesthetic perception and sensitivity to materials.

Another object of the invention is to provide a device of the character described which possesses unique kinesthetic properties by virtue of the interaction between the elastically deformable container and the dilatant suspension contained therein. Because of these unique properties, which are sensed immediately when the container is jabbed, squeezed, pulled, dropped or otherwise manipulated, the principles of the invention are especially adapted for incorporation in toys and amusement devices in a variety of forms and configurations.

Another object of the invention is to provide a device of the character described which can be readily, easily and economically manufactured of innocuous nontoxic, mondeleterious materials.

These and other objects of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

FIG. 1 is perspective view of one form of the invention namely a bag:

FIG. 2 is a sectional view through the bag illustrating the behavior of the device when it is initially compressed or squeezed;

FIG. 3 is a view similar to Fig. 2 illustrating the behavior of the device in the next stage as the squeezing is continued;

FIG. 4 is a view similar to Fig. 3 illustrating the behavior of the device as the squeezing continues and the rate of deformation of the container relates to the characteristic flow rate of the dilatant suspension;

FIG. 5 is a view similar to Fig. 4 illustrating the behavior of the device as it approaches the final squeezing stage;

FIG. 6 is a sectional view through the bag illustrating the behavior thereof when applied to a sharp edge or corner;

FIG. 7 is an elevational view of the bag illustrating the behavior thereof when tension or a pull is exerted on one end thereof;

FIG. 8 is a sectional view of the bag illustrating the behavior thereof when tension or a pull is exerted on opposite ends thereof;

FIG. 9 is a view similar to Fig. 8 illustrating the behavior of the device when the pulls at the ends thereof are continued;

FIG. 10 is a view similar to FIG. 9 illustrating the behavior of the device as it approaches the completion of the end pulling operation;

FIG. 11 is a view similar to Fig. 10 illustrating the behavior of the device when one end is released;

FIG. 12 is a view of a clown's head made in accordance with the principles of the invention;

FIG. 13 is a view similar to Fig. 12 illustrating the behavior of the device when a pull is exerted on various parts;

FIG. 14 is a view illustrating a doll made in accordance with the principles of the invention, the extension of the arm being shown in phantom; and

FIG. 15 is a view illustrating a snake made in accordance with the principles of the invention, the extension of which is shown in phantom lines.

Specific reference is now made to the drawings in which similar reference characters are used for corresponding elements throughout.

In its simplest form the invention comprises a liquid and water vapor-impervious elastically deformable container 10 which, in its relaxed state, is substantially filled with a dilatant suspension 12 in such a manner as to exclude entrapped air. The container is closed off in any suitable manner as by knotting 14, see FIG. 1, or heat sealing as suggested in FIG. 8.

A dilatant fluid is an inverted plastic whose apparent viscosity increases instantaneously with increasing rate of shear. See Chemical Engineers' Handbook, Perry J. H., ed. McGraw Hill Book Co., Inc., 1950, section 17 entitled "Mixing of Material."

The container is made of natural latex or synthetic rubber whose thickness ranges from about 0.006 inch to about 0.009 inch to provide an elongation of 400-800 percent, preferably 600 percent. Conventional toy ballons, surgical gloves, and the like can be employed.

The dilatant filler comprises a liquid suspension of a starch selected from the class consisting of cornstarch or tapioca starch whose granules are near spherical and whose particle size is substantially uniform and within the range of about 0.0001 inch to 0.0004 inch or 2.5-10 microns. To prevent sedimentation or settling out of the starch the specific gravity of the starch particles should approximate that of the liquid. Thus the starch should be suspended in a saturated salt solution which also acts as a preservative to prevent spoilage. The liquid portion must be large enough to lubricate the particles when the suspension is in its initial or resting state but small enough to cause particle-to-particle contact and friction on imposition of a sudden stress or deformation. Thus the starch suspension should contain 42- 46 percent liquid portion by weight or 58-54 percent starch by weight of the total mass of the suspension. Illustrative be nonlimitative, examples of the making of the dilatant suspension and the filling of the elastically deformable container are as follows:

EXAMPLE 1

Three hundred fifty-eight gms. of a saturated saline solution is heated to about 100.degree. F. 420 gms. of cornstarch is added with agitation. When the suspension becomes homogenous and is still warm, it is poured into the container until it occupies about 2 80 percent of the volume of the container. The container is then compressed until the suspension reaches the neck of the container at which time the container is closed off by knotting or sealing the same. In its final condition, the container is substantially free of air.

EXAMPLE 2

The same procedure as Example 1 is followed except 460 gms. of tapioca starch is used instead of cornstarch.

EXAMPLE 3

The same procedure as Example 1 is followed except that 358 gms. of water and 440 gms. of cornstarch are used.

The intriguing paradoxical properties of the present device result from the interaction between the highly elastic deformable container 10 and the dilatant, substantially air-free, suspension 12 therein. Thus if the device is squeezed between the fingers as seen in Fig. 2, the compressive force initially indents or distorts opposing portions of the container as at 16 and 18, causing the particles to flow away from the impact points outwardly towards the ends of the container as shown by the arrows 20. If the compressive force is so sudden that portion 22 of the dilatant suspension between the finers or the locus of the applied force densifies as seen in FIG. 3, it feels like a dense putty. However as the compressive force is continued with constant pressure, the dense portion 22 liquifies as seen at 14 in Fig. 4 and the particles of said portion flow outwardly away from the points of applied force towards the ends of the container as represented by the arrows 26. In the near final stage shown in FIG. 5 the dilatant suspension apparently densifies again forming a small lump 28 of particles trapped between the fingers. Continued pressure eventually .cent.dissolves" this lump and the opposite portions 16 and 18 of the elastic container meet. Thus the psychorheological effects encountered when the device is squeezed are, in sequence, the sensations of initial deformation, then that of a firm solid, followed by that of a slow melting away of the solid, then the feel of a lump or nodule and finally the feel of the lump melting away.

If the compressive impact is delivered to the device in the form of a sudden blow or poke the sensation encountered is that of an initial slight indentation or transformation of the container followed by a sudden encounter of a solid, dense almost impenetrable mass. Thus the device is in fact an excellent impact absorber. An example of this almost "indestructible" impact absorption property is seen in FIG. 6 which illustrates what happens when the device is cropped on a sharp solid object 30 supported on a sturdy surface 32. The initial impact causes an indentation 34 to form in the device and initial densification of the dilatant particles between the indented and the opposite portion 36 of the elastic container 12 because there is a greater rate of flow around the object 30 and therefore a greater shear rate. Then the particles of the dense portion flow outwardly away from the impact locus in the manner shown in FIG. 4. As a result, the device so-to-speak drapes itself around the pointed object 30.

If the device is handled gingerly with the tips of the fingers or rolled rapidly between the palms, there seem to be solid lumps contained therein, whereas on slower handling the lumps vanish by liquefaction.

The rate at which the dilatant suspension flows linearly through an orifice having an area of 2 cm..sup.2 can be called characteristic flow rate or CFR. Since the flow actually is laminar, the effective area of the orifice is about 0.57 cm..sup.2. It is believed that the foregoing phenomena of densification and liquefaction are related to the characteristic flow rate. Thus if the force applied suddenly to the container acts to cause the dilatant suspension to exceed its characteristic flow rate in any portion thereof, densification or hardening occurs at that portion. On the other hand, if the compressive force is applied slowly and continuously to the container at a rate causing the flow in any portion of the volume to be less than the CFR of the dilatant suspension, the device will deform smoothly without encountering lumps or densified portions. It has been found that for enjoying the tactile and kinesthetic properties of the device and increasing tactile sensitivity the CFR should be in the order of magnitude of 1-10 cm./sec. Above 10 cm./sec. the dilatant suspension behaves more like water and below 1 cm./sec. the deformation and flow is too slow to be of interest. The preferred CFR is about 3-6 cm./sec.

The behavior of the device and the sensations felt when a pull or tension is applied thereto is illustrated in FIGS. 7-11. When the fingers of one hand first grasp the device indentations are formed as at 38 and 40 as shown in FIG. 7. Similarly indentations 42 and 44 are formed when the device is first grasped by the other hand at its other end as shown in FIG. 8. If the container is slowly extended at a rate less than the CFR of the dilatant suspension to a length of about six times its original diameter, the particles of the suspension will flow smoothly inwardly from container wall 10 to the center of the device and outwardly towards the ends of the device as shown by the arrows 46 in FIG. 8. Upon release, the container will not snap back to its original diameter slowly as it would if it were filled with water or even a more viscous Newtonian fluid. Rather it returns to its original diameter slowly at the CFR rate of the suspension during which the container may twist or bend as at 48, see FIG. 11, and appear alive. It is important that very little air be trapped in the container since it breaks down the adhesion between the walls of the elastic container 10 and the enclosed dilatant suspension 12 which is likely to fracture rather than elongate in a smooth fashion.

On the other hand when the pull is exerted on the opposite ends of the container suddenly and at a rate in excess of the CFR of the dilatant suspension, as shown in FIG. 9, spaced densified areas or lumps 50 will appear and as the elongation is continued, the compressive force of the container on the lumps will cause them to smooth out or liquefy, so-to-speak during which time the particles will flow outwardly of the densified areas towards the ends of the container as shown illustratively by the arrows 52 and towards the center of the container as shown illustratively by the arrows 54. When the elongated container is attaining a lump-free condition, as shown in FIG. 10, the flow of the particles is substantially to the less compacted portion of the container as shown illustratively by the arrows 56. When one end of the container is released, the particles continue moving towards the center of the container as shown illustratively by the arrows 58, and the released end 48 twists and turns and acts as if it were alive before the container attains its original shape.

The principles of the invention may be applied to containers of varied configurations. Thus as shown in FIG. 14, the container may be formed as a doll having a body portion 60, a head and face portion 62, arms 64 and legs 66 and filled with the dilatant starch suspension in the manner previously described. Thus if a child should grasp and squeeze the body suddenly, for example, lumps will first appear which will dissipate on continued squeezing and when released, the body will slowing return to its original shape, twisting as it returns, to simulate live action. Similarly if the arm, for example, is slowly elongated as shown in phantom lines, it will return slowly on release and the end of finger and wrist portion 67 will twist as did the portion 48 shown in FIG. 11.

If the elastic container 10 is made up in the form of a snake or reptile, as shown in FIG. 15, having a head portion 68 and a body portion 70, a child can amuse himself and acquire tactile sensitivity in many ways. Thus he can elongate all or portions of the snake rapidly and form a plurality of lumps as in FIG. 9 which ultimately will become absorbed and when released and dropped on a surface will twist and wiggle until it returns fully to its original shape and form.

If the elastic container is made up in form of a clown's head as shown in FIGS. 12 and 13, containing, for example, a peaked cap 72, ears 74 and facial features including a bulbous nose 76, the child can be amused and acquire tactile sensitivity by manipulating the features in various ways. Thus the cap 72, or ear 74, or nose 76 can be pulled out as shown in FIG. 13. If pulled out suddenly at a rate in excess of the CFR of the dilatant starch suspension in the head, the elongated features will be formed with lumps which will eventually dissipate. If pulled out slowly at the CFR rate of the dilatant suspension, the elongation will be smooth. In either case, a release of features will cause them to twist and wiggle and act alive before returning fully to their original shape and form. Similar effects can be obtained by squeezing various features. The behavior and physical characteristics of the device results from the interaction of the impervious elastically deformable container and the dilatant suspension contained therein.

Thus, on severe and rapid compression, the unenclosed suspension tends to abruptly fracture and separate before the advance of the compressing surface whereas in the case of the enclosed suspension the wall of the container tends to distribute the force of the compressing object over a greater area (due to sheer between container wall and suspension) add the centrally acting volumetric constraint tends to hold the momentary aggregate together resulting in a more gradual crushing of the momentary aggregate rather than an abrupt fracture and separation.

On rapid elongation, the unenclosed suspension fractures in a "glassy" fashion cleanly and abruptly with little effort whereas when the suspension is enclosed, two effects are produced. The initial pull solidifies the suspension and, with continued pull, the compressive forces normal to the elongation axis cause and inward crushing of the momentary aggregate. As crushing proceeds, the container simultaneously contracts radially (compresses towards the center axis) and elongates. Portions of the system that have not crushed appear as hard nodules or lumps. On sustained elongation or extension the crushed and solid (lumpy) material liquifies. Potential energy is now stored in the elastic walls of the extended container. When the container is released, the walls of the container contract instantaneously. This instantaneous motion causes shearing of the suspension in excess of the CFR, causing solidification. The continuous contracting force of the container then causes a gradual flow of the material toward the regions of minimal density. Finally the system assumes a minimal energy configuration defined by the volumetric constraint of the container (surface tension), the combination of gravity and the surface upon which it is resting and any other forces which might be acting on the system.

Claims

I claim:

1. An amusement device to enhance human tactile and kinesthetic perception and sensitivity comprising a liquid and water vapor-impervious elastically deformable closed member and a dilatant suspension whose apparent viscosity increase instantaneously with increasing rate of shear contained in said member, the member being free of entrapped air, whereby manipulating the device will create unusual distortions, recovery and flow properties.

2. The combination of claim 1 wherein said dilatant suspension consists essentially of cornstarch or tapioca starch particles dispersed in an aqueous medium.

3. The combination of claim 2 wherein the dilatant suspension contains 58-54 percent by weight of the starch providing near-spherical particles whose particle size is substantially uniform and within the range of about 2.5-10 microns and manifests a characteristic flow rate of 1-10 cm./sec.

4. The combination of claim 3 wherein the member is made of rubber and of such thickness as to provide 400-800 percent elongation.

5. The combination of claim 1 wherein the member is made of rubber and of such thickness as to provide 400-800 percent elongation, the dilatant suspension comprising cornstarch or tapioca starch dispersed in an aqueous medium.

6. The combination of claim 5 wherein the aqueous medium is a saturated saline solution.

7. The combination of claim 1 wherein the member is in the form of a doll.

8. The combination of claim 1 wherein the member is in the form of a human head.

9. The combination of claim 1 wherein the member is in the form of a reptile.

10. The combination of claim 2 wherein the liquid portion is large enough to lubricate the particles when the suspension is at rest but small enough to cause particle-to-particle contact and friction on imposition of a sudden stress to the member at the locus of the imposed stress.