WO2004098691A1

WO2004098691A1 - Infant blanket with optional heartbeat simulator device

Info

Publication number: WO2004098691A1
Application number: PCT/US2003/013929
Authority: WO
Inventors: William E. Cooper; Jeffrey L. Gates; Linde Schlumbohm Julien; Denis R. Bourdeau
Original assignee: Heart 2 Heart Products, Llc
Priority date: 2003-05-01
Filing date: 2003-05-01
Publication date: 2004-11-18
Also published as: AU2003232049A1

Abstract

The present invention broadly relates to the care of human infants. More particularly, the present invention concerns apparatus methods that create a sleeping environment for an infant or small child. The present invention specifically is directed to a baby blanket (10) that includes an optional heartbeat stimulator (50).

Description

I

INFANT BLANKET WITH OPTIONAL HEARTBEAT SIMULATOR DEVICE

FIELD OF THE INVENTION

The present invention broadly relates to the care of human infants. More particularly, the present invention concerns apparatus methods that create a sleeping environment for an infant or small child. The present invention specifically is directed to a baby blanket that includes an optional heartbeat simulator device.

BACKGROUND OF THE INVENTION

One of the strongest human instincts involves the care and nurturing of offspring. Parents provide for their children in a wide variety of ways. At a basic level, however, most parents provide their children with the necessities of food, clothing and shelter. While the needs of children last from birth through later years, the care and nurturing of newborns and young infants present special issues. As is well known, infants are somewhat helpless in interacting with their environment and rely upon others to assist and care for them.

One of the aspects of infant care is the provision of sleeping accommodations for the infant. A wide variety of beds, cradles and cribs are used as a resting place for the infant. Various cushions, pads and blankets may be employed to increase the comfort of the infant during the sleep activity. Moreover, numerous cushion devices, such as sleep positioners are sometimes used to create a better sleeping environment for a young child.

Despite these various devices and comfort items, some infants exhibit difficulty in entering the sleep state. It is known to use certain props to relax an infant to help the infant fall asleep. For example, various tactile items such as stuffed animals, silk blankets, etc., may be placed in an infant's bed so that the infant may be comforted. As such an environment becomes more familiar to the child, it is thought that it is easier for the child to fall asleep. It is also known to provide audible relaxation aids for a child with these audible aids including singing to the child, recorded music, mechanical sound devices and the like. It is also thought that simulating the sound of the human heart can help relax an infant or young child. In earlier times, a ticking clock placed next to an infant was thought to relax the infant and assist the infant's slumber. This was because the ticking of the clock, for example, at one second intervals is close to the rate of the human heart thereby providing a rudimentary simulation of the heartbeat. This ticking concept has evolved into more elaborate devices which simulate the human heart. One such device creates a gurgling sound that simulates the heartbeat and related tones that are audible in the womb so that a young infant is soothed thereby during the sleep state. It is known to place such a device, for example, inside of a stuffed animal.

One such device, for example, is described in International Application PCT/AU90/00100, International Publication No. W091/13647 entitled Sleep Inducing Device. Another such device is described in U.S. Patent No. 5,063,912 to Hughes issued November 12, 1991. While these devices are used to generate an audible tone, it is also known to provide sensory input to an infant in the form of a heartbeat vibration in order to calm the infant. One such device is shown in U.S. Patent No. 3,419,923 issued January 7, 1969 to Cowan. In U.S. Patent No. 3,994,282 issued November 30, 1976 to Moulet an astatic multivibrator is provided for producing audible sounds simulating the human heartbeat. U.S. Patent No. 4,124,022 issued November 7, 1978 to Gross also provides an audible tone as a sleep aid. In U.S. Patent No. 6,004,259 issued December 21, 1999 to Sedaros, a device is shown wherein a mother may record her own heartbeat so that this heartbeat may be played back for an infant as a sleep inducement or sleep relaxation aid.

In U.S. Patent No. 5,205,811 issued April 27, 1993 to Fomarelli a baby blanket with a heartbeat simulator of the vibratory type is disclosed. Here, the heartbeat simulator is placed inside of a foam form, and the foam form may be placed inside of a blanket upon which an infant may rest. The heartbeat simulator is pressure activated so that the weight of the infant on the simulator activates the simulator for a selected duration. Most of the devices described above rely on batteries as their power sources. The reason for this, of course, is simple. It is undesirable to have electrical currents at higher voltages in the proximity of an infant lest the infant be placed in danger of electrical shock. However, the use of battery supplies for the various devices has some disadvantages. Typically, it is necessary to deactivate the device. Sometimes this is inconvenient for the parent and can even result in inadvertently awakening the infant. In the case of the Fornarelli device, it is necessary to remove the infant in order to deactivate the unit. On the other hand, should the parent not deactivate the unit, the batteries may be discharged and lead to replacement at an unacceptable cost and inconvenience.

Accordingly, despite the advantages of the preexisting devices, there remains a need for improved infant blankets that are comfortable for an infant placed thereon as well as being comforting to the infant during use. There is also a need for improved heartbeat simulators which can be used in conjunction with such infant blankets. There is a need for such a heartbeat simulator that accurately reproduces the tone of a beating human heart.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and useful blanket which may be used for an infant either as a blanket on which the infant sleeps or as a blanket which may cover the infant.

It is a further object of the present invention to provide an infant blanket constructed of flexible materials, at least some of which are either waterproof or hydrophobic.

Another object of the present invention is to provide an infant blanket with a heartbeat simulator that accurately mimics the human heart.

A still further object of the present invention is to provide a heartbeat simulator that has at least two modes of operation of different duration.

Yet another object of the present invention is to provide an infant blanket with a heartbeat simulator that is self deactivating after one or more pre-selected interval of times. According to the present invention, then, an infant blanket is provided. Broadly, this infant blanket includes a pad of selected size and shape that is formed of compressible material. An innercasing is provided that includes a first casing layer and a second casing layer each constructed of a waterproof material and joined together around a periphery thereof. The casing rests as an interior that is sized and adapted to receive the pad therein through a mouth in closed fitted relationship. The mouth allows access to the casing interior such that the pad may be inserted through the mouth and into the casing to define an encased pad. The infant blanket also includes an outer shell that is sized and adapted to receive the encased pad therein in close fitted relationship. This outer shell includes a first shell layer and a second shell layer each constructed of a flexible material and joined together on the periphery so as to have a shell interior into which the encased pad may be inserted. An entryway is formed in the shell so that the encased pad may be inserted into the shell interior.

In the exemplary embodiment, the pad is constructed of a resilient foam material and the pad, the casing and the shell are each rectangular in shape. The waterproof material out of which the casing is formed is described as a fabric having a waterproof coating. The flexible material forming the outer shell may include fabrics such a cotton and cotton blends as well as other similar fabrics.

In the exemplary embodiment, the first shell layer of the outer shell includes an outer panel formed of a fabric material, such as a cotton or cotton blend, and an inner panel formed of a hydrophobic material, such as nylon. If desired, the first shell layer may include an intermediate panel formed of a batting material. The inner panel and the intermediate panel may be quilted together.

The entryway into the shell interior may be provided with cooperative mating fasteners so that it may be retained in the closed position yet open to allow insertion of the encased pad. This entryway may be formed in the second shell layer. Here, the second shell layer may be formed by first and second paneled sections which have overlapping margins to create the entryway. Hook and loop fasteners may then be located on the overlapping margins to provide the fasteners for the entryway.

The present invention can also, if desired, include an electronic simulator that is adapted to be placed within the outer shell. For example, the pad can have an opening formed at a central portion thereof, and the heartbeat simulator device can be disposed in the opening. The heartbeat simulator device includes an activation switch. When the encased pad is inserted into the outer shell, the activation switch can register with an index marking located on the exterior the shell. This index marking may be configured, for example, as a heart.

The heartbeat simulator described in this invention includes a power supply, an activation switch, heartbeat simulation circuitry that is operative to produce a heartbeat signal, a timing control device operative to establish a time interval for the heartbeat signal and a heartbeat output device operative in response to the presence of the heartbeat signal to generate a simulated heartbeat. The activation switch may, for example, be a piezoelectric element.

The heartbeat simulator can be constructed so that the activation switch is selectively actuable to place the heartbeat simulation circuitry in a first mode of operation wherein the time interval for the heartbeat signal is of a first duration and a second mode of operation when the time interval for the heartbeat signal is of a second duration different from the first duration. The heartbeat simulation circuitry can be in a passive state until a first actuation of the activation switch where upon the heartbeat circuitry is placed in a ready state. A second actuation of the activation switch within a selected time period after the heartbeat circuitry is in the ready state places the heartbeat simulation circuitry in the first mode. A third actuation of the activation switch within the selected time period after the heartbeat simulation circuitry is in the ready state places the heartbeat simulation circuitry in the second mode. The simulated heartbeat, in any event, can be a series of pulses at a selected pulse frequency, such as a pulse frequency of about one heartbeat per second. Each pulse can include a first pulse burst and a second pulse burst that are temporally spaced apart from one another by a burst interval. The heartbeat output device may be responsive to the first pulse burst to produce a first output of a first magnitude and may be responsive to the second pulse burst to produce a second output of a second magnitude that is less than the first magnitude. The burst interval may be approximately 0.3 seconds. Each of the first and second pulse bursts may be for a time of approximately 0.06 to 0.07 seconds. Moreover, each of the first and second pulse bursts can have a pulse burst frequency of approximately 60 cycles per second.

The simulated heartbeat in the disclosed embodiment is primarily a vibratory output. However, due to the packaging of the circuitry, this vibratory output can have an audible component. The heartbeat simulator can also include a low battery indicated circuit as well as various test circuits as desired.

In another form of the claimed invention, a infant blanket is provided that includes a pad of selected shape and thickness and formed of a compressible material with the pad having an open bay formed therein. A heartbeat simulator is disposed in the open bay with this heartbeat simulator being of the type described above. An outer shell is then provided of the type described above to receive the inner pad therein.

Here, again, the outer shell may be constructed as described above and the pad can be constructed of a resilient foam material. If desired, the pad can be received in an inner casing of a type described above where the inner casing includes a first casing layer and a second casing layer each constructed of a substantially waterproof material.

These and other objects of the present invention will become more readily understood and appreciated from a consideration of the following detailed description of the exemplary embodiments of the present invention when taken together with the accompanying drawing in which: BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of an infant blanket according to the exemplary embodiment of the present invention;

Figure 2 is a perspective view, similar to Figure 1 , but showing a portion of the infant blanket of Figure 1 broken away to reveal the construction thereof;

Figure 3 is an exploded side view in cross section showing the construction of the infant blanket of Figures 1 and 2;

Figure 4 is a side view in elevation and partially broken away in cross section showing the construction of the infant blanket of Figures 1 and 2;

Figure 5 is a top plan view of the pad and electronic heartbeat simulator used according to the present invention;

Figure 6 is a side view in elevation illustrating the entryway for insertion of the pad of Figure 5 into the outer shell of the infant blanket according to the present invention;

Figure 7 is a block diagram showing the operation of the electronic heartbeat simulator of Figure 5;

Figures 8(a) and 8(b) is a circuit diagram for the heartbeat simulator according to the exemplary embodiment of the present invention; and

Figure 9 is a graph of a heartbeat signal according to the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present invention broadly relates to infant blankets, but more specifically relates to an infant blanket and a method of creating a simulated heartbeat for use with that blanket. Thus, the present invention is directed to a specific blanket structure as well as the structure of a heartbeat simulator that is used with such blanket. It should be understood, however, that the heartbeat simulator according to the present invention could be used in other applications other than the blanket. Accordingly, the present invention not only includes these structures but the methods contemplated thereby.

With reference first to Figure 1 , it may be seen that infant blanket 10 according to the exemplary embodiment of the present invention is in the form of a blanket upon which an infant may be laid during restful activities or, otherwise used with respect to the comfort of an infant. Infant blanket 10 is shown in Figure 1 to be a rectangular pad of suitable size and shape. While infant blanket 10 is shown to be rectangular in shape, it should be appreciated that any other shapes are within the scope of this invention. For example, infant blanket 10 may have a general size of about 34 inches long, 21 inches wide and approximately 1 inch thick.

As is shown in Figures 1-4, infant blanket 10 includes an outer shell 12 having a flexible first shell layer 14 and a flexible second shell layer 16 which are joined to one another around a periphery 18 so as to create an interior 19 therein. If desired, a decorative ruffle 20 may extend around the perimeter of infant blanket 10. An index marking 21 , in the form of a decorative heart, is centrally located on infant blanket 10 and, specifically, is located centrally of first shell layer 14. The purpose of index marking 21 will become more apparent in the description of the heartbeat simulator, discussed below.

As may be best seen in Figures 2-4, the first shell layer 14 is preferably a sandwich construction formed by an outer panel 22, an inner panel 24 and an intermediate panel 26 which are joined to one another. Inner panel 24 is preferably a hydrophobic material, such as a polyester taffeta lining, that is quilted to intermediate panel 26 which, in this exemplary embodiment, is any suitable batting material, such as a six ounce polyester fill. However, the batting could easily be cotton, cotton blends and the like. Inner panel 24 is breathable so as to pass air and moisture, but does not itself absorb moisture. Outer panel 22, on the other hand, is preferably formed of a cotton or cotton blend fabric of a type acceptable for use with infants. Second shell layer 16 is formed by first panel section 28 and a second panel section 30 also formed of a cotton, synthetic, cotton/synthetic blend, synthetic blend or other fabric material. Panel sections 28 and 30 have respective overlapping margins 32 and 34. The overlap of panels 32 and 34 provide an entryway 36 into the interior 19 of outer shell 12. Each of panel sections 28 and 30 are shown to be formed of a material such as that used for outer panel 22.

In construction, inner panel 24 is first quilted to intermediate batting panel 26. Thereafter, outer panel 22, the quilted inner panel and batting 26 along with panel sections 20 and 30 are joined around peripheral 18, such as by stitching. This creates an open interior 19 that is adapted to receive an encased pad that includes a pad 38 and an inner casing 40. Inner casing 40 includes a first casing layer 42 and a second casing layer 44 each formed of a flexible material that is joined along three sides so as to create a casing interior 46 having a mouth 48 through which pad 38 may be inserted. First and second casing layers 42 and 44 may be constructed of a flexible water resistant or waterproof material so as to inhibit the passage of fluids from the exterior into the casing interior 46 to prevent contamination of pad 38. A suitable material is a fabric with a waterproof coating impregnated therein.

Pad 38 is preferably formed of a foam rubber material and, as illustrated, is a rectangular piece of material approximately 21 inches by 33 inches by 1/2 inch thick. Accordingly, casing 40 has similar dimensions since it is desirable that pad 38 be received in inner casing 40 in close fitted relationship. With reference to Figure 5, it may be seen that foam pad 38 has a central opening or bay 54 formed therein for close fitted receipt of the electronic heartbeat simulator 50, described below. Heartbeat simulator 50 includes an activation switch 52, also discussed below. Here, however, it should be appreciated that the thickness of heartbeat simulator 50 is the same as or slightly less than the thickness of foam pad 38.

In assembly, heartbeat simulator 50 is placed in open bay 54 and the assembled pad 38 is inserted through mouth 48 and into casing interior 46 of inner casing 40 to define and encased pad. The encased pad is then inserted through entryway 36 of outer shell 12 (Figures 3 and 6). This assembly is similar to the insertion of an encased pillow into a pillow sham. However, in order to retain outer shell 12 in a fastened state, the overlapping margins 32 and 34 of panels 28 and 30 are respectively provided with mating fasteners 33 and 35, as is shown in Figures 4 and 6. Fasteners 33 and 35 can take any form known in the art, such as a zipper, snap, buttons and the like, although in the exemplary embodiment, fasteners 33 and 35 are cooperative hook and loop fasteners that extend transversely and completely across entryway 36 between the opposite side edges of outer shell 12. When this assembly is accomplished, it should be understood that activation switch 52 of heartbeat simulator 50 registers with index marking 21 so that a user may know the approximate location of activation switch 52 when heartbeat simulator 50 is in position.

In addition to the new and useful construction of infant blanket 10, described above, the present invention also includes a new and useful heartbeat simulator that produces an extremely realistic heartbeat output to soothe an infant that is placed on infant blanket 10. Broadly, the heartbeat simulator includes a power supply, heartbeat simulator circuitry that is operative to produce a heartbeat signal, a timing control device operative to establish a time interval for the heartbeat signal and a heartbeat output device that is operative in response to the present of the heartbeat signal to generate a simulated heartbeat. As described more thoroughly below, the circuitry is designed so as to reside in a passive state until a first actuation of activation switch 52. Thereupon, the heartbeat circuitry is placed in a ready state. A second actuation of the activation switch within a selected time period after the heartbeat circuitry is in the ready state places the heartbeat simulation circuitry in a first mode of operation wherein the interval for the heartbeat signal is of a first duration. A third actuation of the activation switch within the selected time period after the heartbeat simulation circuitry is in the ready state places the heartbeat simulator circuitry in a second mode of operation. In the second mode of operation the interval for the heartbeat signal is of a second duration that is different from the first duration.

This heartbeat simulation circuitry is diagrammed in Figure 7 and a circuit diagram for the electric circuit is set forth in Figures 8(a) and 8(b). In these Figures, it may be seen that heartbeat simulation circuitry 100 includes an activation switch that, in the exemplary embodiment, is a tap sensor 102 which is a piezoelectric element 204. However, any suitable switch that can sense actuation by a user might be employed. Upon tapping, piezoelectric element 204 operates to generate an electric signal that is conditioned by pulse conditioning circuit 104. Prior to tapping the piezoelectric element 204, the heartbeat simulation circuit is in a passive state. Here, the power supply 110 is preferably a 4.5 to 6 volt battery source 202. The power supply applies a voltage to pin 8 of micropower comparator chip U4 so that chip U4 is capable of sensing the presence of the tap signal but consumes almost no power, thus preserving battery life.

An ultra low power integrated circuit comparator U4 privides a pulse conditioning subcircuit 104. The electric signal from the piezoelectric element 204 is supplied to pin 3 of comparator U4 for comparison with the battery voltage at pin 2. When comparator U4 sees this electric signal, it conditions the signal to a logic output at pin 1. This logic output is communicated to pin 1 of SR flipflop device U3 which forms an on/off state memory subcircuit 106. Device U3 is is a quad nand-gate with two of the nand-gates 206 and 208 providing the flip flop that latches the power on and power off control signals when a signal is applied to pin 1. The flipflop senses this active low signal and creates a logic low signal at pin 10 due to inverter 210. This powers up the system through a power supply voltage regulator, U1 , so that regulated power is supplied at output A. In greater particularity, the output at pin 10 of flipflop U3 switches transistor 212 (Q1) on so that the battery voltage V_dd is applied to voltage regulator U1 at pin 8. Voltage regulator U1 supplies a stable regulated voltage for the circuit at a slightly reduced voltage. For example, in this circuit, the battery voltage may be six volts and the regulated voltage for system operation is five volts. The flipflop device remains latched until it is reset. Transistor 214 is provided to inhibit the flip-flop U3 from accidentally powering off while U2 is powering up.

This, then, places the electric circuit in a ready state wherein microprocessor observes for additional actuations of tap sensor 102. Upon entering the ready state, the regulated voltage from U1 is applied to microprocessor U2 at pin 8. Microprocessor U2 provides a wave form and system timing 108. Having been placed in the ready state, microprocessor U2 awaits further actuations of tap sensor 102 that occur, if at all, within a selected pre-programed time period, such as three seconds. These signals are received at pin 7 of microprocessor U2. If no further signals are received, microprocessor U2 resets the flipflop. More specifically, microprocessor U2 emits a reset signal at pin 2 that switches transistor 216 (Q5) to achieve reset.

However, if a second signal is received from tap sensor 102 and pulse conditioning circuit 104 within the time period, then the wave form and system timing 108 is placed in a first mode of operation. If both a second and third signal are received from tap sensor 102 and pulse conditioning circuit 104 within the time period, then the wave form and system timing 108 is placed in a second mode of operation. In either case, microprocessor U2 generates a pair of alternating signals 112 and 114 (also referred to as PB1 and PB2) at output pins 5 and 6, respectively. In the first mode, these signals 112 and 114 are generated for a first duration; in the second mode, these signals 112 and 114 are generated for a second duration that is longer than the first duration.

Signals 112 and 114 are communicated to transducer drive 116. Transducer drive 116 acts to switch a perceptible output 118, such as vibratory transducer X1. Transducer X1 then produces the heartbeat signal according to signals 112 and 114 from waveform and system timing 108. It should be understood that output devices other than vibratory transducer X1 could be employed, such as a speaker that would produce an audible output. Microprocessor U2 is programmed to produce outputs PB1 and PB2 at pins 5 and 6 for a selected duration of time. Processor U2 is programmed to produce a first pulse burst at output 5 and a second pulse burst at output 6 with these first and second pulse burses being temporarily spaced by a burst interval programmed into processor chip U2. Each of these pulse bursts may be at a selected pulse burst frequency of about 60 cycles per second. A pair of first and second pulse bursts defines a heartbeat pulse which has a selected pulse frequency that is also programmed into processor U2.

When the first pulse burst, PB1, is produced at pin 5 of processor U2, is presented to transistor 218 (Q3). Similarly, when the second pulse burst signal is present at pin 6, as PB2, it is presented to transistor 220 (Q4). Transistors 218 and 220 thus define the switches for transducer drive 116 with each of these transistors having inputs connected to transducer X1. Transistors 218 and 220 are connected in parallel between transducer X1 and ground. Thus, when a signal is present, current may flow through transducer X1 from power supply 110 to ground. However, as may be seen in Figure 8(a) transistor 220 is connected transducer X1 through resistor 222 (R29) so that the magnitude of the perceptible signal generated by transducer X1 is greater when transistor 218 is switched on then is the case when transistor 220 is switched on. This output lasts for the first or second durations, depending upon how many times microprocessor U2 sensed taps from tap sensor 102 (piezoelectric element 204).

With reference again to Figures 7 and 8(a), a second portion of comparator U4 may be used as a low battery detector circuit 120 to compare the actual battery voltage in power supply 110 with a minimum level. This is accomplished by the voltage divider circuit including resistors R9 and R32 for the battery voltage and R8 and R10 for the regulated voltage. If the ratio of voltages drops below a preselected level, low battery detector 120, formed by a portion of comparator U4, signals wave form and system timing 108 at 122 to generate signals at 112 and 114 to cause transducer 118 to generate a different output to signal the user that a low battery condition exists. A diagnostic test indicator subcircuit 124 is shown in Figures 7 and 8(b). This sub circuit can be used during manufacture to ascertain that the heartbeat simulator device is performing. Specifically, upon entering the ready state, microprocessor U2 is also programmed to output a short duration signal at pin 3. This signal is presented to transistor 222 (Q6) which, when so switched, allows current to flow through light emitting diode 224 (LS1). The visible output indicates that microprocessor U2 has been activated.

With the overall concepts of the heartbeat simulator circuit 100 now being revealed, a greater appreciation may be had for the actual electronic circuit of the heartbeat simulator 50 with this circuit being set forth in Figures 8(a) and 8(b). The components of this circuit diagram are set forth in the following table:

CIRCUIT PARTS

Resistors ; (ohms)

R1 1M R13 1M R25 1.0

R2 0 R14 1M R26 10K

R3 1M R15 1M R27 100K

R4 1M R16 100K R28 1.0

R5 1M R17 1M R29 4.7

R6 1M R18 100K R30 1.2M

R7 1M R19 1M R31 680

R8 33K R20 100K R32 33K

R9 22K R21 100K R33 0

R10 33K R22 100K R34 10K

R11 1M R23 100K

R12 1M Capacitors (uF) Micro Farads

C1 4.7/16V

C2 10.0/16V

C3 2.2/16V

C4 2.2/16V

C5 1.0/16V

C6 22/16V

C7 0.1

C8 0.01

Transistors

Q1 SI 2301

Q2 SI 2301

Q3 SI2302

Q4 SI2302

Q5 2N7002

Q6 2N7002

DIODES

D1 S1 B

D2 1 N4148

DSI LED1

LOGIC/INTEGRATED CIRCUITS

U1 LM2936M-5.0 U2 ATtiny12L-4SI

U3 CD4093

U4 TLC3702CD

X1 Transducer

PE Piezoelectric element

The operation of the system can now be appreciated with greater particularity and with reference to Figure 9 showing two representative heartbeats 300 and 302 separated by a pulse frequency that is approximately one beat per second. Each pulse 300, 302 includes a first pulse burst 304 and a second pulse burst 306 which are temporally spaced by a burst interval, ti which, in this embodiment, is selected to be about 0.3 seconds. Each of first and second pulse burst 304 and 306 last for a duration of about 1/15 second (0.06 to 0.07 seconds) and is produced at a frequency of about 60 hertz so that each includes about 4 cycles per burst. A second pulse burst 306 is separated from the next occurring first pulse burst 304 a time interval "t₂" that is approximately 0.6 seconds. Each of pulse bursts 304 and 306 is As may be seen the intensity "I" of pulse burst 306 is less than pulse burst 304.

With reference again to Figures 8(a) and 8(b) and with the understanding that microprocessor U2 is programmable to selected intervals, heart simulator device 50 reacts to the users tapping of piezoelectric element 204 as hereinafter described. Upon a first activation of piezoelectric element 204, sub circuit 104 through half of integrated circuit U4 moves the system from a passive state to a ready state. If piezoelectric element 204 is actuated a second time within a selected time period, such as three seconds, after being placed in the ready state, the heartbeat simulation circuitry is placed in a first mode of operation. If it is actuated a third time with the selected time period, the heartbeat simulation circuitry is placed in a second mode of operation. In each mode of operation, processor U2 produces a heartbeat signal in the form of pulse bursts PB1 and PB2 which are separated approximately three tenths of a second apart. A pair of pulse burst signals is produced approximately once a second with each pulse burst being at a 60-hertz frequency. The first pulse burst PB1 signal is applied to transistor 218 which cycles transistor 218 approximately four times during the approximate 1/15th second that PB1 is generated so that transducer X1 activates for a 1/15th second interval at the 60-hertz rate. This corresponds to pulse burst 304 of Figure 9. Processor U2 then turns off the signal PB1 and waits for approximately 0.3 seconds at which time it generates a second pulse burst, PB2, which is applied to transistor 220. This second pulse burst again lasts approximately 1/15th of a second at a 60 hertz frequency so that transistor Q4 turns transducer X1 on and off approximately four times during this 1/15th of a second. Due to the presence of resistor 216, the magnitudinal intensity, however, is reduced from that of the first pulse burst, and this corresponds to pulse burst 306 shown in Figure 9. Processor U2 then waits for a time period t₂ of approximately 0.6 seconds and then cycles through another set of pulse bursts.

The difference between the first and second mode of operation is the time interval the heartbeat signal is produced. In the first mode, signals PB1 and PB2 are produced for a set time of about ten seconds. In the second mode, signals PB1 and PB2 are produced for a set time of about twenty minutes. In either event, after the timeout of the mode, microprocessor generates a reset signal to flipflop U3 to turn the system off and return it to the passive state.

Pulse bursts 304 and 306 are each illustrated as square wave pulses which are believed fully adequate to simulate a heartbeat in an effective manner. However, if a more sinusoidal heartbeat is desired, this can be accomplished by placing another transistor in parallel with transistors 218 and 220. In the circuit shown, transistor 222 can be employed for this second function in addition to the test circuit function. For example, circuit point 226 could be connected to circuit point 228 through a small resistance (such as a 2 ohm resistor (not shown)). Microprocessor U2 could then be programmed to produce a third heartbeat signal, indicated as optional signal PB3, which would switch transducer X1. By selecting the combinations of signals PB1 , PB2 and PB3 and by reducing the time interval of output updates or changes, for example, by a factor of eight, the programmer could produce pulse bursts that mimic a sinusoidal wave but still keep the same heartbeat frequency and the same pulse burst separation and frequency.

Accordingly, the present invention has been described with some degree of particularity directed to the exemplary embodiments of the present invention. For example, the ordinarily skilled person in this field should recognize that the selected frequencies, durations and time intervals may be configured as desired. It should be appreciated, though, that the scope of the present invention is defined by the following claims construed in light of the prior art so that modifications or changes may be made to the exemplary embodiment of the present invention without departing from the inventive concepts contained herein.

Claims

We claim:

1. An infant blanket comprising:

(A) a pad of selected size and shape and formed of a compressible material;

(B) an inner casing including a first casing layer and a second casing layer each constructed of a waterproof material and joined together around a periphery thereof to have a casing interior that is sized and adapted to receive said pad therein in close-fitted relationship, said casing having a mouth formed therein to allow access to the casing interior whereby said pad may be inserted through the mouth and into the casing interior to define an encased pad; and

(C) an outer shell including a first shell layer and a second shell layer each constructed of a flexible material and joined together around a periphery thereof to have a shell interior that is sized and adapted to receive said encased pad therein in close-fitted relationship, said shell having an entryway formed therein to allow access to the shell interior whereby said encased pad may be inserted through the entryway and into the shell interior.

2. An infant blanket according to claim 1 wherein said pad is constructed of a resilient foam material.

3. An infant blanket according to claim 1 wherein said pad, said casing and said shell are each rectangular is shape.

4. An infant blanket according to claim 1 wherein said waterproof material is a fabric having a waterproof coating.

5. An infant blanket according to claim 1 wherein said first shell layer includes an outer panel formed of a fabric material and an inner panel formed of a hydrophobic material.

6. An infant blanket according to claim 5 wherein said first shell layer includes an intermediate panel formed of a batting material.

7. An infant blanket according to claim 6 wherein said inner panel and said intermediate panel are quilted together.

8. An infant blanket according to claim 1 wherein the entryway is formed in said second shell layer.

9. An infant blanket according to claim 1 wherein said first and second casing layers have a common size and shape and are joined around a majority of a common peripheral edge such that said mouth is formed by an unjoined portion of the common peripheral edge.

10. An infant blanket according to claim 1 wherein said first and second shell layers each include a fabric material.

11. An infant blanket according to claim 10 wherein said fabric material is selected from a group consisting of cotton, synthetic, cotton/synthetic blend, and synthetic blend.

12. An infant blanket according to claim 1 wherein said pad has an opening formed in a central portion thereof and including a heartbeat simulator device disposed in the opening, said heartbeat simulator device including an activation switch.

13. An infant blanket according to claim 12 wherein said shell includes an index marking at an exterior location such that, when said encased pad is inserted into said shell, the activation switch registers with the index marking.

14. An infant blanket according to claim 13 wherein the index marking is configured in a heart shape.

15. An infant blanket according to claim 1 including a heartbeat simulator device, said heartbeat simulator including a power supply, an activation switch, heartbeat simulation circuitry that is operative to produce a heartbeat signal, a timing control device operative to establish a time interval for the heartbeat signal, and a heartbeat output device operative in response to the presence of the heartbeat signal to generate a simulated heartbeat.

16. An infant blanket according to claim 15 wherein said activation switch is a piezoelectric element.

17. An infant blanket according to claim 15 wherein said activation switch is selectively actuable to place said heartbeat simulation circuitry in a first mode of operation wherein the time interval for the heartbeat signal is of a first duration and a second mode of operation wherein the time interval for the heartbeat signal is of a second duration different from the first duration.

18. An infant blanket according to claim 17 wherein said heartbeat simulation circuitry is in a passive state until a first actuation of said activation switch whereupon said heartbeat circuitry is placed in a ready state, wherein a second actuation of said activation switch within a selected time period after said heartbeat circuitry is in the ready state places said heartbeat simulation circuitry in the first mode and wherein a third actuation of said activation switch within the selected time period after said heartbeat simulation circuitry is in the ready state places said heartbeat simulation circuitry in the second mode.

19. An infant blanket according to claim 15 wherein the simulated heartbeat is a series of pulses of a selected pulse frequency.

20. An infant blanket according to claim 19 wherein each said pulse includes a first pulse burst and a second pulse burst temporally spaced by a burst interval, said heartbeat output device responsive to the first pulse burst to produce a first output of a first magnitude and responsive to the second pulse burst to produce a second output of a second magnitude that is less than the first magnitude.

21. An infant blanket according to claim 20 wherein the selected pulse frequency is about one heartbeat per second.

22. An infant blanket according to claim 21 wherein the burst interval is about 0.3 second.

23. An infant blanket according to claim 22 wherein each of said first and second pulse bursts is for a time of about 0.06 to 0.07 seconds.

24. An infant blanket according to claim 23 wherein each of said first and second pulse bursts has a pulse burst frequency of about 60 cycles per second.

25. An infant blanket according to claim 15 wherein the simulated heartbeat is a vibratory output.

26. An infant blanket according to claim 15 wherein said heartbeat simulator includes a low battery indicating circuitry.

27. An infant blanket according to claim 1 wherein the entryway is provided with releasable fasteners to secure the entryway in a closed state yet releasable whereby the entryway may be opened to allow insertion of the encased pad.

28. An infant blanket according to claim 27 wherein said second shell layer is formed by first and second panel sections having overlapping margins that define the entryway, said releasable fasteners being disposed on said overlapping margins.

29. An infant blanket comprising:

(A) a pad of selected shape and thickness and formed of a compressible material, said pad having an open bay formed therein;

(B) a heartbeat simulator device disposed in the open bay, said heartbeat simulator device including a power supply, an activation switch, heartbeat simulation circuitry that is operative to produce a heartbeat signal, a timing control device operative establish a time interval for the heartbeat signal, and a heartbeat output device operative in response to the presence of the heartbeat signal to generate a simulated heartbeat, said activation switch being selectively actuable to place said heartbeat simulation circuitry in a first mode of operation wherein the interval for the heartbeat signal is of a first duration and a second mode of operation wherein the interval for the heartbeat signal is of a second duration different from the first duration; and

30. An infant blanket according to claim 29 wherein said pad is constructed of a resilient foam material.

31. An infant blanket according to claim 29 wherein said first shell layer includes an outer panel formed of a fabric material and an inner panel formed of a hydrophobic material.

32. An infant blanket according to claim 31 wherein said first shell layer includes an intermediate panel formed of a batting material interposed between said outer panel and said inner panel.

33. An infant blanket according to claim 29 wherein said outer shell includes an index marking at a location such that, when said pad is inserted into said outer shell, said activation switch registers with the index marking.

34. An infant blanket according to claim 29 wherein said heartbeat simulation circuitry is in a passive state until a first actuation of said activation switch whereupon said heartbeat circuitry is places in a ready state, wherein a second actuation of said activation switch within a selected time period after said heartbeat circuitry is in the ready state places said heartbeat simulation circuitry in the first mode and wherein a third actuation of said activation switch within the selected time period after said heartbeat simulation circuitry is in the ready state places said heartbeat simulation circuitry in the second mode.

35. An infant blanket according to claim 29 including an inner casing including a first casing layer and a second casing layer each constructed of a flexible substantially waterproof material and joined together around a periphery thereof to have a casing interior that is sized and adapted to receive said pad and said heartbeat simulator therein in close-fitted relationship, said casing having a mouth formed therein to allow access to the casing interior whereby said pad may be inserted through the mouth and into the casing interior to define an encased pad.