DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

[0020] Referring to FIGS. 1 and 2, one embodiment of a flashing ball 10 according to the present invention has an outer rubber ball 12 direct compression molded or otherwise formed over a hollow inner ball 14 which contains an impact-responsive flasher circuit having two alternately flashing LEDs 22 and 24 spaced apart from each other and oppositely oriented with respect to a printed circuit (pc) board 28. The circuit in FIG. 1 shows the lens portion of the body of LED 22 and the base of LED 24, the lens portion of which protrudes through the pc board, as shown in FIG. 2, through a hole provided for this purpose. The flashes are preferably provided in alternating bursts of, for example, three to five flashes from each LED, with an individual flash frequency of 18 Hz and a 50% duty cycle. Each flash cycle consists of one burst from each LED, and the circuit is preferably designed to operate at a rate of three flash cycles per second for a total of 32 cycles each time it is triggered. An example of a suitable flasher circuit is shown in FIG. 8, and representative waveforms of the voltage across each LED are illustrated in FIG. 9, wherein the individual flash period T equals 55 msec, corresponding to 18 Hz. The leads 18 and 20 of the LEDs are electrically connected in a conventional manner via traces on pc board 28 to an IC 16, which is similarly mounted on the pc board in a conventional manner.

[0021] The spaced arrangement of the LEDs combines with the above-described flash sequence to produce a startling visual effect. The effect is believed to be more attention-getting than that of a single flashing LED or even a pair of alternately flashing LEDs which provide alternating single flashes rather than alternating flash bursts as in the present invention. Center-to-center spacing of approximately 10-15 mm has been found suitable for producing the desired effect.

[0022] A suitable IC is a type Al615-A one-shot IC, commercially available from Allegro Electronics Ltd., Kwaichung, N.T. Hong Kong. A suitable LED is a Sunscreen type L53SRCU red LED. The LED anodes may be connected together as shown and connected to the positive terminal of the battery through a current-limiting resistor R1. Switch 26 is connected between the negative battery terminal and the one-shot (OSH) input of the IC and is preferably an inertial switch of the coil spring type, mounted on the pc board with its longitudinal axis perpendicular to the board as shown in the drawings and as described in more detail below. The circuit is preferably powered by two series-connected 1.5-volt button cells 30, e.g., AG10 cells, which are electrically connected to the IC by a board-mounted button cell holder and a terminal on the board surface. Greater battery capacity may be provided for some applications; for example, other embodiments include three button cells 30 and two or more blue or white LEDs. The sidewalls of the button cells are preferably electrically insulated from the laterally adjacent surfaces of the button cell holders by high-temperature insulating tape, e.g., mylar, which may be applied at discrete points or entirely around the button cell circumference.

[0023] The button cells are held in position by support posts 32 and 34 in cooperation with the button cell holder and the pc board, which is supported by posts 36, 38 and 40. The support posts are integrally formed on respective hemispheres 42 and 44 as shown in further detail in FIGS. 3 and 4, respectively, which along with FIGS. 1 and 2 are scale drawings. The two hemispheres are designed to snap together, and for this purpose the battery-side hemisphere 42 is provided with an annular projection 46, and the circuit-side hemisphere 44 is provided with a corresponding annular groove 48 shaped and sized to mate with projection 46. Alternatively, hemisphere 44 may be provided with an annular projection and hemisphere 42 a corresponding annular groove.

[0024] Switch 26 may be an inertial switch of the type shown in U.S. Pat. No. 5,725,445 to Kennedy et al., which patent is incorporated herein by reference. As can be appreciated from FIGS. 1 and 2, the switch includes a coil spring and a rod extending through the coil spring along the longitudinal axis thereof. The coil spring may be formed from 0.2 mm wire. A diameter of approximately 4 mm and an axial length of approximately 4.5 mm are presently preferred dimensions for the coil proper, which is spaced from the board surface as shown. A spacing of 2-2.5 mm from the board is suitable, and may be maintained with a lead having two 90° bends, one portion of the lead extending parallel to the axis of the coil as shown, a second portion extending along the board surface perpendicular to the first portion and away from the coil axis, and a third portion extending from the outer end of the second portion parallel to the coil axis and through the board. The spacing from the board may be somewhat longer, e.g., approximately 3 mm or longer in some applications, and the axial length of the coil may also be somewhat longer, e.g., 5-6 mm or longer. Shorter coils with less spacing from the board are also contemplated as useful in some applications. The number of wire turns per unit of axial length may be greater at the free end of the coil than at the fixed end as shown in FIG. 2. The switch sensitivity is preferably set such that, with the coil axis in a horizontal plane, the assembled ball must be dropped vertically a minimum of approximately one inch onto a rigid surface to momentarily close the switch and thereby trigger the flasher circuit.

[0025] The outer ball is composed of a thermosetting resin such as cis-butadiene rubber and dicumyl peroxide, with an outer diameter of approximately 50 mm, and the hollow inner ball is molded acrylic or polycarbonate with an outer diameter of approximately 30 mm as shown in the scale drawings. Other ball sizes are also contemplated, including, for example, a 60 mm ball with a 40 mm inner ball. One example of a suitable outer ball material is cis-1,4-polybutadiene rubber. The hardness of the outer ball is in the range of 30-70 durometer in one embodiment, and in the range of 35-55 durometer in another embodiment. The outer ball is initially formed as two uncured hemispheres of desired wall thickness, each having a center recess sized to receive the inner ball. The inner ball is enclosed within the two hemispheres and sealed therein by oven curing at approximately 400° F. for approximately 30 minutes with the two hemispheres held together.

[0026] The inner and outer balls may both be transparent, or both translucent, or one may be transparent and the other translucent. Both balls are transparent in one embodiment in which the outer surface of the outer ball is treated to facilitate application of printing ink. The treatment may include an ultrasonic wash for approximately 15 minutes, for example. The outer surface is preferably roughened by means of bead blasting. A desired logo, company name, advertising slogan or other information is then printed on the roughened surface, e.g., by pad printing and heat curing of the ink for approximately 1 hour at 120° F. It has been found suitable for such purposes to bead blast a circular area on the surface having a diameter approximately three-fourths that of the outer ball. Alternatively, a roughened outer surface may be provided by the mold itself. A suitable ink for such purposes includes type “WNT” ink and BH hardener available from Trans Tech America, Inc., Carol Stream, Ill., mixed with two adhesive components in the following percentages by weight: 2

[0027] Alternatively, a desired logo, etc., may be printed on the outer surface of the hollow inner ball. The outer ball is transparent while the inner ball hemispheres are preferably molded of translucent polycarbonate rather than transparent polycarbonate or other suitable material to provide desired contrast for the printing on its surface. A light color is preferred for the inner ball to provide contrast for black or other dark color ink, and a white matte finish is particularly desirable. The desired surface finish is provided in the molding process itself or by subsequently roughening the outer surface of the ball, e.g., by bead blasting, tumbling or sanding with, e.g., 400-800 grade sandpaper. In one particular example, the outer surface of the inner ball is roughened with #240 quartz in a tumbler for approximately 25 minutes. This surface treatment has been found to enhance ink retention, increase the adhesion of molded synthetic rubber to the inner ball, and avoid discoloration believed to be caused by air trapped during the molding process. The ink is applied and heat cured as described above.

[0028] FIG. 5 is a partially cutaway view of the complete ball from the perspective of FIG. 1. Outer ball 12 is depicted as transparent, and inner ball 14 appears larger than actual size due to refraction, as indicated by circumferential line 52 representing the apparent periphery of the inner ball, the actual size of which is as shown in the cutaway portion of the drawing. The properties of the inner and outer balls combine to create a zone of internal reflection and/or refraction between the peripheries of the two balls and thereby produce a halo effect, or a ring of light, around the inner ball during each flash of the back-side LED (LED 24 in this view), as indicated by curved arrows 50 in the drawing. The ring of light appears to fill the space between the apparent periphery 52 of the inner ball and the periphery of the outer ball. The effect is more pronounced when the flashing ball is viewed from the perspective of FIG. 1 or from the opposite perspective, i.e., from an angle substantially perpendicular to the plane of the circuit board, and held with the finger or palm of one's hand, or other object, against the back side of the ball, especially in low light or in the dark. The halo effect is in addition to the light visible directly through the inner ball from the near-side LED 22 and significantly enhances the visual impact of the flashing ball and thereby attracts greater attention. In the case of a translucent inner ball, light emitted from near-side LED 22 is visible as a flashing spot in the inner ball. The visual impact is especially enhanced as the halo flashes in bursts which alternate with the flash bursts from the near-side LED.

[0029] Referring now to FIG. 6, which relates to another aspect of the present invention, a flashing keychain 60 comprises a keychain 62 combined with a smaller size flashing ball 64 of the type described above. The inner ball and included circuit, and the outer ball, are the same as those of FIGS. 1 and 2, except that the outer ball is smaller, e.g., approximately 40 mm in one embodiment, and a connecting pin 66 is provided in the ball as shown in FIG. 6. Keychain 62 is connected on one end to an eyelet 68 on pin 66 and includes a keyring 70 on its other end. The pin includes a flange 72 on its inner end for retention within the ball. The flange may extend radially from the pin axis in multiple directions as shown in FIG. 6, e.g., 360°, or may extend radially in only one direction as shown in FIG. 7 at 74. A hole is provided in the inner ball at the seam between the two hemispheres to receive the main body of the pin, which may be placed between the two hemispheres during the assembly process so as to be captured within the hole when the two hemispheres are snapped together. The outer ball is then molded over the assembled inner ball in a conventional manner. A desired logo, company name, advertising slogan or other information may be printed on the surface of either the inner ball or the outer ball as described above. The flasher circuit is preferably triggered by forces greater than a predetermined magnitude, such as the magnitude of force generated upon impact of the ball with a solid object, e.g., a table top, at the end of a 1″ vertical drop as described above. The flasher circuit is preferably not triggered by the low level of forces encountered by a person walking, for example.

[0030] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention.