DYNAMIC MATTRESS SUPPORT AND METHOD OF OPERATION

Abstract: An infant environmental transition system provides an infant with controlled simulated movements encountered by an infant in an intrauterine environment. The system includes a suspension system having a plurality of flexures coupled between a base plate and a moving mattress platform. A cam shaft assembly includes a groove that engages a linear follower connected to the moving bed platform so that the follower moves along the groove while the cam shaft assembly rotates to move the linear follower, and thereby reciprocate the moving mattress platform in a longitudinal direction. Alternatively, a rotating crank assembly translates crank rotation to reciprocating movement of the mattress platform, a detented rocker arm promotes safe, override protection of actuator producing rocking movement. The cam shaft assembly also includes an eccentric cam coupled to a rocker that is coupled to one of the flexures to angularly displace the moving mattress platform support on the flexures, and thereby provide the composite reciprocating and rotational movements of the moving mattress platform that simulate the intrauterine environment. Pulses of variable width control operating speed of a drive motor, and proximity sensor associated with driver cam shaft provide operational feedback for speed regulation and safe shutdown under excessive loading or other adverse operating conditions. Pulse width modulation techniques generates sounds and operate visual indicators on control panel.

Description: DYNAMIC MATTRESS SUPPORT AND METHOD OF OPERATION Related Cases This is a continuation-in-part application of pending application Serial No. 08/602,277 entitled "Cradle Mattress", filed on February 16, 1996 by Gerald V. Beemiller, et al. and the subject matter of this application is related to the subject matter of Patent No. 5,037,375, issued on August 6, 1991, which subject matter is incoφorated herein by this reference. Field Of The Invention This invention relates to mattresses, and more particularly to mattresses that simulate stimuli, including motion and sound, experienced by an infant in an intrauterine environment. Background Of The Invention Animals have the ability to adapt to many and varied environmental conditions. The limit of adaptation depends mainly on the animal's absolute physiological limitations and the rate of environmental change or adaptive pressure to which it is subjected. Perhaps the most difficult transition a mammal is required to make in its lifetime is the change from the intrauterine environment to the extrauterine environment at birth. Every parameter of the infant's environment changes abruptly. Dramatic shifts in temperature, tactile sensation, audio stimuli, motion, and light are exacerbated by conditions in the hospital delivery room where most women in modern societies give birth. Even the environment in a loving home is alarmingly unfamiliar, and many infants exhibit prolonged crying and sleeplessness which may be related to transitional stress. It is believed that these abrupt changes in the environment tend to intensify the infant's intrauterine to extrauterine transition and may inflict harm which affects the person's emotional and physical response to adaptive or environmental change throughout the remainder of his or her life. Therefore a gradual and effective transition of the infant from the intrauterine environment to the extrauterine environment may have substantial long-term as well as short-term benefits. An effective transition system would duplicate as closely as conveniently possible the intrauterine conditions perceived by the infant just prior to birth. It would also provide means for gradually altering environmental stimuli over time until they reflect the natural extrauterine environment. The environmental stimuli vary in complexity and ease of simulation or control. The motion parameter is quite distinctive. Figure 1 shows the characteristic pelvic displacement patterns of pregnant women while walking. Duplicating the linear and rotational components of these motions is difficult and requires a sophisticated suspension and motion control and drive system. U.S. Pat. No. 4,079,728 discloses a programmable environmental transition system that provides and controls a number of environmental stimuli and modifies them over time from initial values closely approximating what the fetus perceives in the uterus just prior to birth to final values typical of the extrauterine environment. Rather than duplicate any particular motion pattern, the system imparts a general rocking motion to the infant, who is suspended therein on a net-like sling. U.S. Patent No. 5,037,375 discloses an infant environmental transition system and method that provides a controlled transition from an intrauterine environment to an extrauterine environment. This system includes a motor assembly within the housing below the cradle. A pulley assembly driven by a belt drives shafts within the housing to impart movement to a cradle. It is desired to have a motion system that is sufficiently small in size and in height to fit into conventional cribs and mattresses. Summary Of The Invention The present invention incorporates a motion-oriented environment within a mattress structure and includes a suspension and motion control and drive system which very closely replicates the intrauterine motion the fetus experiences as the mother is walking. Microprocessor based electronics integrate desired changes in motion and other stimuli to gradually transition the infant from the simulated intrauterine environment to the extrauterine environment, and to provide wide ranging system flexibility. Previous suspension systems had undesirable complexity of the motion mechanism and could produce unacceptable levels of noise. The present invention overcomes these significant deficiencies and produces motion which is quiet, smooth and continuous with high safety and reliability and low maintenance. The electric motor and control electronics may be housed within a control module separately from the mattress structure supporting the infant. Alternatively, the electric motor and drive mechanism may be disposed within the mattress separated from the control module. The motion drive system within the mattress structure may include holomorphic coupling between components in one embodiment to provide unique determinable movement of one component in response to movement of another component. In another embodiment, flexure modules that also support an articulating central portion of the mattress structure may be actuated by direct mechanical linkage from a motor and drive system that are disposed within and beneath the central portion of the mattress structure. The mattress structure is of conventional size and is easy to move. Brief Description Of The Drawings Figure 1 is a graph showing the characteristic pelvic motion patterns of pregnant women while walking, which patterns are emulated by the motion parameters of the present invention. Figure 2A is an exploded, perspective view of a mattress structure and of the subsystems housed within the central portion of the mattress structure of an environmental transition system according to the present invention. Figure 2B is a cross-sectional view of the mattress structure and of the subsystems along a line 2B-2B of Figure 2A. Figure 3 A is a top cutaway view of the subsystems within the mattress structure. Figure 3B is a cross-sectional view along a longitudinal axis showing the subsystems within the central portion of the mattress structure. Figure 3C is a cross-sectional view along a transverse axis showing the subsystems within the central portion of the mattress structure. Figures 4A and 4B are side and top views, respectively, of a rocker assembly according to one embodiment fastened to a flexure of the motion mechanism within the central portion of the mattress structure. Figure 5 A is top view of a controller unit according to one embodiment. Figure 5B is a front view of a control panel for the controller unit. Figure 5C is a plan view of the circuit details assembled on the control panel of Figure 5B. Figure 6 is a side view of the controller unit according to the embodiment of Figure 5 A. Figure 7 is a cross-sectional view of a hydraulic system according to one embodiment for actuating the subsystem within the central portion of the mattress structure. Figures 8 A and 8B are top and bottom views, respectively, of a mattress pad for positioning over the subsystem within the central portion of the mattress structure. Figure 9 is a top cross-sectional view of the subsystem within the central portion of the mattress structure of Figure 2 A. Figure 10 is a side cross-sectional view of the subsystem of Figure 9 with an actuator housing and cam shaft assembly removed. Figure 11 is an end cross-sectional view of the subsystem according to one embodiment showing the coupling of a rocker to the cam shaft assembly and to a center flexure. Figure 12 is a block diagram of the controller unit for the subsystem within the mattress structure. Figure 13 is a top view of a subsystem within the mattress structure using thermal actuators according to another embodiment. Figure 14 is a top view of the subsystems housed within the mattress structure according to still another embodiment of the present invention. Figure 15 is a top view of the motion mechanism in the embodiment of Figure 14. Figure 16 is a side view of the motion mechanism of Figure 15. Figure 17 is an end view of the flexure and the platform locking mechanism in the embodiment of Figure 14. Figure 18 is a sectional view of a gear and crank and bearing system in the motion mechanism of Figure 15. Figure 19 is a top view of a platform locking receptacle in the motion mechanism of Figure 15. Figures 20A, 20B, 20C, and 20D are, respectively, top plan, side sectional, and bottom views of the locking mechanism in the embodiment of Figure 15. Figure 21 is a plan view of a detented rocker arm for actuating rocking movement in the embodiment of Figure 15. Figure 21 A is a plan view of an alternative embodiment of a rocker arm. Figure 22 is a top view of the rocker arm of Figure 21. Figure 22 A is a top view of the alternative rocker arm of Figure 21 A. Figure 23 is a top view of the rocker arm of Figures 21 and 22 installed in the embodiment of Figure 15. Figure 24 is a block schematic diagram of electrical control circuitry for the mattress structure according to the present invention. Figures 25A-25M comprise a flow chart of the operating routine according to one embodiment of the present invention. Detailed Description Of The Preferred Embodiment Referring now to Figures 2-14, there is illustrated environmental transition systems including suspension and motion control and drive systems, and including a stimulus integration and modulation system, according to different embodiments of the present invention. The environmental transition systems provide for a gradual, controlled transition for an infant by initially simulating its intrauterine environment and gradually transitioning to the extrauterine or everyday environment, thereby reducing adaptive shock and permitting healthy, gradual adaptation. This transition is accomplished according to the present invention which initially reproduces environmental motions regularly sensed by an infant prior to birth. In particular, each embodiment provides and transmits to the occupant, via the suspension and motion control and drive systems, a motion which a fetus experiences as the mother is walking. The transition systems are controlled to vary the motion in a day-night cycle and to reduce stimuli over time until the occupant is exposed to minimal motion approximating the everyday environment. Referring specifically to Figures 2A and 2B, the mattress structure includes a perimeter mattress portion 102 having a box-like shape formed, for example, of resilient foam material and having thick sidewalls and bottom surface that are stationary and firm. The sidewalls and bottom house, support, and constrain a motion mechanism 103. A motion platform 104 has a top surface near the top surface of the surrounding or perimeter portion of the mattress 102 and is supported for motion along several axes by a suspension system including flexures 106 (see Figures 3A, 3B, 3C). The mattress structure 102 includes a soft, form-fitting mattress pad 108 having a bottom surface affixed to the top surface of the motion platform 104 and having a top surface mattress pad 108 disposed for supporting an infant. Lower edges of the mattress pad 108 are tapered 180, as illustrated in the sectional view of Figure 2B, to mate in sliding engagement with tapered surfaces 181 near the upper, inner longitudinal and lateral edges of the perimeter mattress portion 102. In this way, longitudinal and lateral movements of the mattress pad 108 relative to the perimeter mattress portion 102 do not significantly alter the contour of the top surface of the combined structure, and integral flexures or hinges 182 formed within resilient foam material of which the pad is formed facilitate greater flexibility of the pad near the perimeter thereof, as more fully described later herein with reference to Figures 8 A and 8B. Referring specifically to Figures 3A, 3B, and 3C, the mattress structure may also include a sound transducer or speaker 110 disposed on the motion platform 104 beneath the level of the top surface of the mattress pad 108. The sound transducer 110 may include one or more signal sources connected thereto such as a phonograph, tape player, electronic signal generator, or similar controllable sound generator for generating a variety of different simulated sounds or actual recordings, for example, of the noises present in the near-term pregnant uterus. The transducer 110 and associated signal source may also provide other sounds such as music or house sounds which may be generated electronically, recorded on tape, or played from a remote transmitter (not shown) and reproduced via a receiver (not shown) as a signal source in the mattress structure. The sounds are reproduced from the sound transducer 110, which is suitably mounted below the mattress pad 108 to direct sounds toward the infant or occupant that may be gradually changed over a period of a few months, for example, from intrauterine sounds to sounds typical of the outside world. The motion platform 104 is supported by the suspension system which includes two thin flexures 106 at opposite ends that are formed of plastic, or the like, and that have their pivots 105 in the center portion of the flexure 106 affixed to the base plate 112 via lower mounting brackets 1 14 as shown in Figure 3B. The flexure supports 106 have their outer ends affixed to the motion platform 104 via upper mounting brackets 116. The flexures 106 preferably include compliant sections 111 that flex so that the flexure 106 hinges accommodate linear motion along the longitudinal axis 123 of the motion platform 104. The flexures 106 are substantially symmetrical about a longitudinal central axis 123 and are flexible at the compliant sections 111 along the longitudinal direction between the longitudinal central axis 123 and opposite ends of the flexures 106 and are rigid along a vertical axis between the longitudinal central axis 123 and the opposite ends of the flexures 106. This specific design enables the motion platform 104 to undergo essentially linear motion along the longitudinal central axis 123 and rotational motion along an axis substantially aligned with the longitudinal central axis of the perimeter portion 102 of the mattress structure while supporting the motion platform 104 that is constrained against lateral movement. As the motion platform 104 moves relative to the base plate 112, the flexures 106 hinge at the compliant sections 111 in a direction along the longitudinal central axis 123 of the mattress structure. The motion platform 104 supports and carries the mattress pad 108 via the flexures 106 and associated parts as described below. The upper mounting brackets 116 on a bottom surface of the motion platform 104 each have a claw-like structure to grasp a flexure end 184 of one of the flexures 106. Additionally, the upper mounting bracket 116 may include "snap" latches that allow the end 184 of the flexure 106 to be quickly inserted in the upper mounting bracket 116 and be retained therein after such insertion. The end 184 of the flexures 106 are flexures that are approximately perpendicular to the body of the flexure 106. The ends 184 have compliant sections 185 that flex so that the ends 184 hinge to accommodate the flexing of the body of the flexure 106 during the linear movement of the motion platform 104. As the motion platform 104 moves, the body of the flexure 106 hinges at the compliant sections 111 and pulls on one end 184 to thereby bend the end 184 at the compliant sections 185 to pull the end 184 toward the longitudinal axis 123 and in the direction of the linear movement. The other end 184 is pushed to thereby bend that end 184 at the compliant sections 185 thereof and to push the end away from the longitudinal axis 123 and in the direction of the linear movement. The flexure 106 includes compliant sections 186, as shown in Figure 3C, arranged approximately perpendicular in the center of the body of the flexure 106 to allow the flexure 106 to twist around the center 105 during the rocking movements. The motion mechanism 130 is anchored to the base plate 112 for driving the motion platform 104, and includes actuators for generating linear motion along a longitudinal axis 123 of the mattress pad 108, and for generating rotational or rocking motion thereof about the longitudinal axis. The actuator may be, for example, a conventional hydraulic piston and cylinder mechanism including a Belofram (TM) hydraulic diaphragm. Referring to the embodiment illustrated in the top view of Figure 3 A, the motion mechanism includes a link 120 that has one end anchored at a pivot 119 to the base plate 112 at a location along the longitudinal axis 123 of the motion mechanism, and has a pivot joint 126 at the other end coupled to one end of link 122. The other end of link 122 is attached through a pivot joint 124 to the motion platform 104. The joint 124 thus moves longitudinally along axis 123 as the pivot joint 126 is rotated about pivot 119 along an arc 135 of movement in response to the linear actuation by slave actuator 128. The links 120 and 122 preferably provide sufficient torsional compliance and compressive stiffness to allow for rocking motion, but to inhibit buckling under longitudinal actuating force applied thereto. The drive rod 127 of slave actuator 128 contacts the link 120 at a bearing point 140 to urge the link 120 to move about the pivot 119, and thereby to urge the link 122 to pivot about the pivot joint 126. As the link 122 pivots, the joint 124 moves longitudinally, thereby to linearly actuate the motion platform 104 in a direction along the axis 123. A return spring 121 is attached to the base plate 112 and to the link 120 to retain contact between the drive rod 127 of the slave actuator 128 and the link 120 throughout the motion cycle. The spring 121 also provides positive differential pressure within the hydraulic system. As the drive rod 127 moves into the slave actuator 128, the spring 121 tension pulls the link 120 toward the actuator 128. This causes the motion platform 104 to move linearly along the direction of longitudinal axis 123. In the particular embodiment shown in Figure 3A, the bearing point is located less than a quarter of the length of the link 120 between the pivot 119 and joint 126 to provide from the arcuate travel 135 thereof a longitudinal stroke at the joint 124 and the attached motion platform 104 of approximately 3/4 inch along the longitudinal axis 123 for an associated angular motion of link 120 of approximately ± 27°. A high degree of lateral stiffness of the flexures 106 relative to their compliance in the direction of the longitudinal axis 123 restrains the motion platform 104 to linear movement along the axis 123 for angular movements of the links 120 and 122, while the rocking movement of the motion platform 104 substantially about the pivots 105 is approximately ± 5°. It is desirable to make the thickness of the mattress structure as close to standard size as possible. In one embodiment, a pulley system, as illustrated in the side and top views, respectively, of Figures 4A and 4B, preferably provide the rocking motion. In these figures, a rocker arm 160 of substantially C-shape is affixed to and extends away from the flexure 106 that is positioned near the pivot 119. A flexible cable 142 is affixed to the rocker arm 160 at ends 141 and to the link 120 at rotatable attachment 143. The distance between the attachment point 143 and pivot 119 relative to the distance between the ends 141 and the axis of the pivot 105 of flexure 106 is selected to produce a nominal angle of rocking motion of the motion platform 104 for the movements of link 120 of approximately ± 5°. The slave actuator 128 drives the link 120 along its angular path to thereby drive the cable 142. The rotatable attachment 143 reciprocates in a plane substantially parallel to the base plate 112 and the pulleys 161 are pivoted on supports (not shown) on the base plate 112 to convert the reciprocating motion at attachment 143 to reciprocating motions of the cable at ends 141 of the rocker arm 160 in opposite phase relationship and in a plane substantially normal to the base plate 112. The flexure 106 to which the rocker arm 160 is attached is constrained to rotate about the longitudinal axis of the pivot 105, and the oppositely-phased movements of cable 142 at the ends of rocker arm 160 thus cause the rocker arm 160 and flexure 106 and the motion platform 104 attached thereto 116 to rotate about the pivot 105. This assembly thus creates two reciprocating longitudinal cycles per rocking cycle to simulate motions of the platform 104, for example, as experienced by a fetus within a uterus as link 120 reciprocates about axis 119. Referring specifically to Figures 5A and 6, there are shown top and side views, respectively, of a controller unit 148 which includes an actuator 128, a housing 150, a controller drive mechanism 151, a control panel 152, a controller module 154, and a motor 156. The controller unit 148 is preferably outside and near the mattress structure. The controller drive mechanism 151 converts electrical input applied to the controller unit 148 into mechanical motion that translates within the motion mechanism previously described to linear and rocking motion of the motion platform 104 and mattress pad 108. The electrical input is converted into mechanical motions by motor 156 and then to hydraulic forces and motions within the controller unit 148, and hydraulic forces and motions are then transferred to the slave actuator 128 of the motion mechanism 103 within the mattress structure. The control panel 152, as shown in Figures 5B and 5C may be formed, for example, as a plastic membrane disposed over push button selectors. The control panel 152 includes a start button 153 and a stop button 155 to enable and disable, respectively, the controller module 154, and includes a day selector 157 to select day motion settings, a night selector 159 to select night motion settings, an age selector 146 to select where in a time-varying motion program the infant of certain age properly fits, and a display 147 such as a conventional Liquid Crystal Display (LCD) to display the age in weeks of an infant user. Each of the push button selectors 146, 153, 155, 157, and 159 includes an interlaced array of non-contacting conductors disposed on a printed circuit board 158, with the latter four selectors disposed about central apertures or other clear windows 162 through which light sources 628 may illuminate the selectors. Each such interlaced array may be selectively contacted by a conductive member (not shown) disposed beneath each button location. For example, a spacer layer 164 may include conductive deposits thereon 166 for one or more of the selectors, in alignment therewith, and 'dimpled' out of contact with the associated interlaced array to form therewith a normally-open push button switch. The deposits 166 may be oriented about the aligned apertures 162, or may be transparent or translucent. The controller module 154 controls the operation of the mattress structure, in a manner substantially as described in U.S. Patent No. 5,037,375. Responsive to control signals from the controller module 154, the motor 156 drives the controller drive mechanism 151 to cyclically move a piston in the actuator 128. The motor 156 may be, for example, a low-voltage DC motor that receives low-voltage power from an external power source (not shown). The motor 156 is preferably geared down internally to deliver torque at an output shaft 158 to drive the controller drive mechanism at about fifteen cycles per minute in a day mode and at about ten cycles per minute in a night mode. The controller drive mechanism 151 interconnects the motor 156 to the actuator 128 to transform rotary motion into translational motion. More specifically, one end of an eccentric crank 107 is attached to shaft 158 so that the crank 107 turns as the motor 156 rotates. A first end of a link 109 pivots on the crank 107, and a second end of the link 109 may be attached via a wrist pin to drive rod 127 of actuator 128. The eccentricity of the crank 107 and the link 109 are selected so that rotary motion of the crank 107 produces reciprocal motion of the drive rod 127 of the actuator 128. Alternatively, the controller drive mechanism 151 may include an eccentric cam and a cam-follower (not shown) in which a drive rod 127 slides upon or follows the perimeter of such a cam that turns with the motor shaft 158. Referring to Figure 7, there is shown a cross-sectional view of a hydraulic system according to one embodiment of the present invention which includes two actuators 128, interconnected by a flexible connecting tube 131 having indistensible side walls. The actuators 128 in the controller 148 and in the motion mechanism 103 of the mattress structure form a closed hydraulic system for operation as master and slave units, respectively. The actuator 128 includes a mechanical portion 129 and a hydraulic portion 130, which may be separately housed. The hydraulic portion 130 of the actuator 128 includes a rolling diaphragm, or Belofram 132. The rolling diaphragm 132 precludes leakage between relatively reciprocating components and substantially lacks friction. The actuator 128 may include a connector that provides quick fastening and quick-releasing connection to allow the hydraulic portion 130 to be separated from and reconnected to the mechanical portion 129 without compromising hydraulic integrity. Preferably, the actuator mounted within the motion mechanism 103 includes such a connector to facilitate removal of the hydraulic system from the mattress structure for convenient moving and storage of the mattress structure. The hydraulic portion 130 of each actuator 128 is attached and sealed to an end of the connecting tube 131. The rolling diaphragm 132 of each actuator 128 is also attached and sealed to the housing of the hydraulic portion 130. The outer periphery of the rolling diaphragm 132 may be shaped to form an O-ring and provide mechanical sealing when the hydraulic portion 130 is fastened to the mechanical portion 129. The hydraulic portions 130 of both actuators 128 and the connecting tube 131 thus form a detachable subassembly that is an integral, flexible pressure vessel for hydraulically transferring mechanical motions between the controller unit 148 and the structure. The connecting tube 131 is preferably filled with an incompressible fluid that is preferably non-toxic to humans, such as vegetable oil. For an incompressible hydraulic fluid within such a pressure vessel, the volume of the hydraulic fluid remains constant and a deflection of either rolling diaphragm 132 results in corresponding predeterminable deflection of the other diaphragm, i.e. if the diaphragm 132 of one actuator 128 is deflected toward the connecting tube 131, the diaphragm 132 of the other actuator 128 is deflected away from the connecting tube 131. The hydraulic fluid is preferably at a low positive pressure within connecting tube 131 to facilitate retaining proper shape of the rolling diaphragm 132. A rigid metal disk 133 is disposed in the center portion of the surface of the rolling diaphragm opposite the fluid. The hydraulic portion 130 and the connecting tube 131 preferably cannot be disassembled easily by the user. The mechanical portion 129 of each actuator 128 includes the drive rod 127 positioned within a sliding bearing. One end of the drive rod 127 that extends from the actuator 128 drives or follows the mechanical linkage of the controller drive mechanism 151 or of the motion mechanism 103. The other end of the drive rod 127 is internal to the actuator 128 and is positioned against the disk 133 on the rolling diaphragm 132 to impart driving force thereto. Referring again to Figure 5 A, a position encoder 170, 171 detects the motion cycles of the link 109. The controller module 154 connected to the position encoder 170, 171 may count motion cycles to indicate the need for service or parts change, or to automatically shut down the system to prevent excessive wear or undesirable fatigue failure, if the accumulated number of cycles exceeds a predetermined threshold. The position encoder 170, 171 may include a Hall- effect sensor 170 in a magnetic circuit including magnet 171 affixed to the link 109. A cycle is counted each time the motion of the link 109 moves the magnet 171 in close proximity to the Hall-effect sensor 170. Alternatively, the position encoder 170 may be an optical encoder, variable capacitance encoder, or a Faraday-effect velocity encoder. A bar pattern applied to a motion link in a system including a light source and a light detector within an optical encoder may act as the scale relative to a reticle, to provide digital encoding of link position or cycle counting. Alternatively, the position encoder 170 may provide position and velocity indications to the controller module 154 as feedback signals. Responsive to such feedback, the controller module 154 may vary the rotational speed of the motor 156 in conventional manner. Referring specifically to Figures 8 A and 8B, the perimeter of pad 108 slides on the upper surface of perimeter portion 102 to accommodate the linear and rotational motions of the motion mechanism 103. The mattress pad 108 has chamfered edges 180 along the perimeter bottom surfaces. The perimeter portion 102 has chamfered upper, inner edges 181, as shown in Figures 2A and 2B, that slidably engage and support the chamfered edges 180 of the mattress pad 108. The chamfered edges 180 and 181 preferably are covered by a film or coating with a low coefficient of friction to reduce the force required to move the mattress pad 108 relative to the perimeter portion 102. The motion mechanism 103 preferably bears the weight of an occupant and of the portion of the mattress pad 108 positioned on the motion platform 104. The edges 181 preferably bear the weight of the portion 180 of the mattress pad 108 engaging the edges 181. The mattress pad 108 preferably is formed of a medium density foam and may include a plurality of grooves 182 in the top and bottom surfaces of the mattress pad that form integral hinges of reduced cross sections to accommodate the rocking and longitudinal motions by facilitating the deformation and bending of the mattress pad 108. The perimeter mattress portion 102 is dimensioned to provide clearance between such perimeter mattress portion 102 and the mattress pad 108 to facilitate low- force bending of the mattress pad 108 at the grooves 182. The perimeter mattress portion 102, the mattress pad 108, and the motion mechanism 103 preferably are enclosed in a mattress cover (not shown) that may be disposed in part between chamfered edge 180, 181 and that includes elastic regions to stretch between stationary and moving portions of the mattress structure during the rocking and longitudinal motions of the' mattress pad 108 and supporting motion platform 104. Referring now to the embodiment of the invention illustrated in the top, side and end views, respectively, of Figures 9, 10 and 11 , the motion platform 204 is supported by a suspension system which includes two thin flexures 206 at opposite ends and one thin central flexure 207 that are formed of plastic, or the like, and that have their pivots in the center portion of each such flexure affixed to a base plate 212 via lower mounting brackets 214. The outer ends of each flexure are affixed to the motion platform 204 via upper mounting brackets 216. The flexures 206 and 207 preferably have an S-shape, as shown in the top view of Figure 9, and are substantially symmetrical about the longitudinal central axis. The flexures 206, 207 are flexible in the lateral or width dimension between the longitudinal central axis and opposite ends of the flexures 206 and 207, and are rigid along a vertical axis between the longitudinal central axis and the opposite ends of the flexures 206 and 207. This specific design enables the motion platform 204 to undergo longitudinal motion along the longitudinal central axis, and rotational motion about an axis substantially aligned with the longitudinal central axis while supporting the motion platform 204 that is substantially constrained against lateral movement. As the motion platform 204 moves relative to the base plate 212, the flexures 206 and 207 bend in a direction along the longitudinal central axis of the mattress 202 that is aligned with a cam shaft 232, described below, and can slightly alter lateral dimensions attributable to the longitudinal motions of the ends thereof relative to the central planes of each flexure 206, 207. The motion platform 204 in this illustrated embodiment of the invention supports and carries the mattress pad thereon via the flexures 206 and 207 and associated parts, as described below. The upper mounting brackets 216 on a bottom surface of the motion platform 204 each have a claw-like structure to grasp an end of one of the flexures 206 and 207. Alternatively, the upper mounting bracket 216 may include "snap" latches that allow the ends of the flexure 206 and 207 to be quickly inserted in the upper mounting bracket 216 and retained therein after such insertion. The flexure 207 includes protrusion or actuator stud 217 integral with an extension arm 219. A linear follower 218 is formed of plastic, or the like, and has a portion 220 that is pivotally mounted to the base plate 212, and has a linear portion 222 with a terminal portion 224 affixed to the motion platform 204 via screws, or "snap" latches, or other suitable fasteners. A first integral flexure 226 couples the pivoting portion 220 to a first end of the linear portion 222. A second integral flexure 228 couples the terminal portion 224 to a second end of the linear portion 222 opposite the first end of the linear portion 222. The linear follower 218 operates as a lever for linearly moving the motion platform 204, as described below. The first and second integral flexures 226 and 228 allow the linear follower 218 to bend at these locations during rotational and longitudinal movements of the motion platform 204. An actuator housing 229 that is mounted to the base plate 212 includes a cam shaft assembly 230 as an actuator that couples to the flexure 207 and the linear follower 218 to impart linear and rotational motion to the motion platform 204 supported on the flexures 206, 207. The cam shaft assembly 230 includes a cam shaft 232 that is formed of steel, and includes a barrel cam 234, and a eccentric cam 236. The eccentric cam 236 is attached on an end of the cam shaft assembly 230 opposite the cam shaft 232. The barrel cam 234 has a groove or slot 235 in the outer circumferential surface that engages a linear follower stud 240 which is integrally molded on the pivoting portion 220 of the linear follower 218 to impart to the linear follower 218 linear motion that is aligned with the cam shaft 232 along the longitudinal axis. The groove 235 has a longitudinal displacement in the circumferential surface so that, as the linear follower stud 240 slides within the groove 235, the linear follower 218 linearly moves back and forth along the longitudinal axis. Referring specifically to Figure 11, a rocker arm 242 has a center hole 243 that pivots on a post provided on a side wall of the actuator housing 229, as shown in Figure 10. A cam follower of the rocker 242 engages the eccentric cam 236 on the end of the cam shaft assembly 230. A rectangular hole 245 in the rocker arm 242 engages the actuator stud 217 on the center flexure 207. As the cam shaft assembly 230 rotates, the eccentric cam 236 engages the cam follower and rotates to thereby cause the rocker arm 242 to pivot and impart a rotational rocking motion to the flexure 207 and to the motion platform 204 attached thereto, as shown by the broken lines in Figure 11. Thus, the cam shaft assembly 230 may be rotated to cause the barrel cam 234 to drive the linear follower 218 for imparting longitudinal motion to the motion platform 204, and to impart an angular displacement to the rocker arm 242 that imports a rotational motion to the center flexure 207 via the actuator stud 217 to thereby 'rock' the motion platform 204. In this embodiment, each revolution of the cam shaft assembly 230 imparts two cycles of linear motions and one cycle of rotational motion. The phasing of the linear motion and rotational motions are selected to simulate the movement of a fetus in an intrauterine environment as described in U.S. Patent No. 5,037,375, and may be altered by relatively rotating the fixation of the eccentric cam 236 and the barrel cam 234 on the shaft 230. Referring specifically to Figure 12, a controller unit 248 includes a housing 250, a control panel 152, a controller module 254, a motor 256, and a shaft 258. The controller module 254 controls the operation of the mattress structure, in a manner substantially as described in U.S. Patent No. 5,037,375. The motor 256 may, for example, be a low-voltage DC motor that receives low-voltage power from an external power source (not shown). The shaft 258 preferably is flexibly coupled 259 or otherwise coupled to the cam shaft assembly 230 so that rotational motion of the shaft 258 is transferred to the cam shaft assembly 230. Responsive to control signals from the controller module 254, the motor 256 drives the cam shaft assembly 230 via the shaft 258 and coupling 259 to produce translational and rotational movement of the motion platform 204 in the manner as previously described. The motor 256 preferably drives the cam shaft assembly 230 at about fifteen cycles per minute in a day mode and at about ten cycles per minute in a night mode. The sound transducer 110, as illustrated in Figure 10, may provide intrauterine sounds continuously when the mattress structure is operational, or may be operated to provide such sounds at intermittent, periodic intervals to simulate the intrauterine sounds experienced by a fetus. The linear and rotational movements of the motion platform 204 supporting a mattress pad thereon may be produced as previously described in a random, intermittent, or programmed manner. Referring to Figure 13, there is illustrated another embodiment of the environmental transition system that includes a movement mechanism that is thermally actuated. Such a system includes a base plate 112, a motion platform 104, and flexures 106 as described above. Such a system does not include a motor. Instead, thermal actuators 301 are coupled to the flexures 106 and to the motion platform 104. A controller unit 302 applies electrical power to heating elements 303 adjacent to, or formed by, the thermal actuators 301, which respond to the heat to expand and contract, and thereby impart the linear and rotational motions to the motion platform 104. A heat-removing compound or element (not shown) may be coupled to the thermal actuators 301 and to the heating elements 303 to improve the cooling and contracting of the thermal actuators 301 for controlled responses in varying environmental conditions. Such a system operates quietly in the absence of a motor or conventional actuators as the thermal actuators 301 changes the position of the motion platform 104 in response to either a change of temperature within, or a temperature gradient within, one or more thermal actuators 301. The thermal actuators 301 preferably are formed of bi-metal material as a strip wound into a watch-spring configuration so that heating the actuators 301 winds the spring tighter. Thermal actuators 301 are affixed to the base plate 112 and to ends of the rocker arm 160. Rocking may be produced by alternatively heating the two thermal actuators 301. Similarly, two such elements may be attached to opposite ends of the base plate and to the joint 124 on the motion platform 104. Reciprocating displacement may be produced by alternately heating the two thermal actuators 301. Alternatively, the bi-metal material utilized can be electrically conductive, and the controller 302 applies a current to the thermal actuator 301 to heat the actuator directly. The thermal actuators 301 may be a cold- worked machine element of conventional shape-memory alloy such as titanium-nickel (TiNi) alloys that exhibit super-elasticity and that "remember" the unworked shape when heated to its critical temperature. As temperature exceeds the critical temperature, the force to return the element to its unworked shape increases. Thus, the change in shape from unworked state to cold worked state can be very large. Using shape-memory thermal actuators 301 allows movements on the order of one inch for temperature changes on the order of 10 °C. Referring to the illustrated embodiment of Figure 14, there is shown a top view of the motion mechanism and associated subsystems housed within the mattress structure. The subsystem includes a pair of flexures 106 mounted to opposite ends of the base plate 112. A DC motor 402 receives DC power from a controller and external power source (not shown), such as a conventional AC to DC converter, or step-down transformer that is plugged into a wall power outlet for safety and convenient isolation of high voltage from the controller and mattress structure. A worm gear 404 is mounted to a shaft 406 of the motor 402 for rotation about the rotational axis of the shaft 406. The worm gear 404 includes a helical groove on the outer surface thereof that engage helical teeth of a worm wheel 410 attached to a spur gear 408 mounted to the base plate 112 for rotation about an axis of the worm wheel 410. The spur gear 408 on the worm wheel 410 preferably has 60 teeth. A linear drive link 412 has a first end pivoted on a crank pin 409 on the worm wheel 410 at an offset from the center of the worm wheel 410. The linear drive link 412 has a second end ball jointed to a socket 414 disposed substantially along the centerline of the motion platform 104. As the motor 402 rotates, the worm gear 404 rotates the worm wheel 410 to thereby move the linear drive link 412 in a back and forth linear motion, and likewise move the motion platform 104 and the mattress pad 108 supported thereon. A barrel cam 416 has a peripheral groove that varies in axial elevation about the periphery and has a spur gear 418 having teeth that engage the spur gear 408. The barrel cam 416 rotates about an axis in response to rotation of the worm wheel 410. Roller 420 pivots on a stud on a first end of a cam follower 422. A second end of the cam follower 422 is mounted about the center of one of the flexures 106 to impart rocking motion thereto in response to rotation of the barrel cam 416. The spur gear 418 of the barrel cam 416 preferably has 120 teeth to provide a reduction in gearing and preferably an approximately 2: 1 ratio of linear motion to rocking motion. As the roller 420 follows the barrel cam 416, the cam follower 422 rotates about the axis 123, thereby rotating the flexure 106 and the motion platform 104 in a rocking motion. The motor 402 is controlled by a controller unit (not shown) that includes a control panel and a controller module that provides control signals to the motor in a manner substantially as described above for the controller module 154. Referring now to the top view of Figure 15, there is shown the base plate 112 having supports at opposite ends thereof for supporting the flexures 106 near the centers thereof. The base plate 112 has attached thereto a mount and frame 501 for motor 402 and gears 410 and 418. The crank pin 409 carried on gear 410 reciprocates the link 412 and the associated socket 414 into the motion platform 104 back and forth along the longitudinal axis supported on the flexures 106. In addition, the gear 418 carries a magnet 450 near the periphery thereof for passing in close proximity to a Hall-effect sensor 452 disposed to respond to the magnetic field about the magnet 450 in a manner as described, for example, with reference to magnet and sensor 170, 171 in Figure 5. The base plate 112 also includes a plurality of receptacles disposed substantially near the covers of the base plate to receive therein rotatable locking devices 456, as later described herein, for selectively securing the motion platform 104 to the base plate 112. Referring now to the partial side view of Figure 16, the motion platform 104 is disposed on flexures 106 in the manner as previously described which are centrally supported at pivots 105 on the base plate 112. The mount and frame 501 supports the gears 410 and 418, with crank pin 409 disposed to rotate above the mount and frame 501 to reciprocate the link 412 and socket 414 back and forth in the manner previously described. In addition, the base plate 112 includes a plurality of locking devices 456 positioned in receptacles 455 to engage, or not, the mating pin-like protrusions 458 on the locking device 456 with an associated pin-like protrusion 460 on the motion platform 104, depending upon the rotational orientation of the device 456, as later described herein, and as illustrated in the end view of Figure 17. Referring now to the sectional view of Figure 18, there is shown the gear 410 disposed between the mount and frame 501 and the base plate 112. The gear 410 and associated pinion may be molded in one (or two) piece assembly about the crank pin 409 that carries substantial flats 503 about the perimeter of the shaft 462 to provide good torque-transferring engagement with the gear 410. An upper bearing for the gear 410 is formed by 'swaging' or rolling a hole 510 in the mount and frame 501 to dimensions of the hub 464 of the gear 410 to form an inexpensive bearing of substantial bearing surface to support the gear 410 about its vertical axis against the eccentric forces exerted on the crank pin by the link 412. In addition, the hub 464 of the gear includes an upstanding concentric, circular ridge 466 that is disposed at a diameter greater than the rolled edges about hole 510 in mount and frame 501, and that is disposed with an upper edge thereof at an elevation below the underside of mount and frame 501. In this manner, the gear is mounted for rotation about its central axis, and is axially positioned in the bearing against end play by the ridge 466. Referring now to Figure 19, there is shown one of the plurality of receptacles 455 in the base plate 112 with a locking device 456 disposed therein in orientation with protrusion 458 out of alignment with protrusion 460 of the motion platform 104. With the protrusions 458, 460 thus misaligned, the motion platform 104 is free to undergo longitudinal and rotational motions, as previously described. With reference now to Figures 20A, 20B, 20C, and 20D, there are shown various views of the locking device 456 that is arranged to rotate into position within a receptacle 455 in base plate 112 and be supported therein by protruding tabs 470 that are disposed about the perimeter of the locking device at one or more levels or elevations to facilitate initial aligned fit into the receptacle, and then selective angular positioning thereof in orientations of protrusions 458, 460 aligned, or not, in manner similar to conventional 'bayonet' -type couplers. With all such protrusions 458, 460 aligned, the motion platform 104 is locked against longitudinal and rocking motions to facilitate substantial normal use of the mattress structure (i.e., without the rocking and longitudinal motions). A plenum 472 may be diametrically disposed across the underside of the locking device 456 to facilitate convenient finger gripping to selectively rotate the locking device 456 within the receptacle 455. A resilient tab 474 arranged substantially parallel to a tangent from the generally cylindrical shape of the locking device 456 is disposed to interfere with an abutment in receptacle 455 to impede excessive rotation and to provide tactile feedback into locked and unlock positions. Referring now to the plan and top views, respectively, of Figures 21 and 22, there is shown a rocker arm 509 which couples the barrel cam on gear 418 to the adjacent flexure 106 for imparting the rocking motion to the motion platform 104 as the gear rotates 418 about its axis. Specifically, this rocker arm 509 includes a spring-loaded, detented joint 511 formed about the pivot bolt 513 that attaches the segments 515 and 517 of the rocker arm for rotation about the pivot bolt 513. These segments 515, 517 of the rocker arm 509 are retained against relative rotation about the pivot bolt 513 by the protruding detent 519 in segment 515 and the aligned aperture 521 on segment 517 that require lateral overriding motion along the axis of the pivot bolt 513 against the tension of the cupped spring 523. By selectively tightening the pivot bolt 513 between segments 515, 517, the cupped spring 523 may be pre-biased against lateral movement to thereby increase the torque requirements imposed by segment 515 relative to segment 517 about pivot bolt 513 required to overcome the detent 519 alignment with aperture 521. In this way, the cam-following stud 525 captivated within the barrel cam 416, as shown in the top view of Figure 23, can transfer light torque about the rotational axis 527 of a flexure 106 to which the segment 515 is attached 529. For higher torque loading, due for example to external forcing of the motion platform 104 against normal movement or by excessive off-center weighting of the motion platform 104, then the detent 519 and aligned aperture 521 may exhibit lateral separation of the segments 515 and 517 against the axial force of cupped spring 523 to exhibit a 'break-away' release of the excessive torque loading without adversely affecting the barrel cam 416 and the associated motion mechanism. The segments 515, 517 may be automatically reset (with the excessive torque loading condition removed) with detent 519 and aperture 521 re-aligned as the rocking motion imparted to a flexure 106 and the associated motion platform 104 returns to an extreme tilt about axis 527 against a motion stop (not shown), for example, provided by the protrusions 458 or 460 in the non-aligned, non-locking positions, or provided by the motion platform 104 'bottoming' out about the tilt axis 527 against the base plate 112. Referring now to Figures 21 A and 22 A, there are shown plan and magnified top views, respectively, of an alternative embodiment of a rocker arm 510 according to the present invention. In this embodiment, the rocker arm 510 couples the barrel cam on gear 418 to the adjacent flexure 106 for imparting the rocking motion to the motion platform 104 as the gear rotates 418 about its axis. Specifically, this rocker arm 510 includes a spring-loaded, joint 512 formed about the pivot bolt 514 that attaches the segments 516 and 518 of the rocker arm for rotation about the pivot bolt 514. These segments 516, 518 of the rocker arm 510 are retained against relative rotation about the pivot bolt 514 by the opposed pair of protrusions 520 in segment 516 and the aligned pair of protrusions 522 on segment 518. There opposed sets of protrusions disposed substantially diametrically about the pivot bolt 514 requires lateral overriding motion along the elongated slot 526 in segment 518 in which the pivot bolt 514 slides against the tension of the coil spring 524. By selectively tensioning the coil spring 524 and spacing the protrusions 520, 522 away from the pivot bolt 514, the assembly may be pre- biased against angular movement to there increase the torque requirements imposed by segment 516 relative to segment 518 about pivot bolt 514 required to overcome the pivoting about one set of protrusions 520, 522 against the resilient bias of coil spring 524. In this way, the cam- following stud 525 captivated within the barrel cam 416, as shown in the top view of Figure 23, can transfer light torque about the rotational axis 527 of a flexure 106 to which the segment 516 is attached 529. For higher torque loading, due for example to external forcing of the motion platform 104 against normal movement or by excessive off-center weighting of the motion platform 104, then one pair of the protrusions 520, 522 serve as pivots for segment 518 to slide past pivot bolt 524 within the elongated slot 526, thereby to exhibit a 'break-away' release of the excessive torque loading without adversely affecting the barrel cam 416 and the associated motion mechanism. The segments 516, 518 may be automatically reset (with the excessive torque loading condition removed) with both pairs of protrusions 520, 522 held in engagement by spring 524 to serve as a rigid rocker arm with torque-limiting capability. Referring now to the schematic drawing of Figure 24. there is shown the control circuitry according to one embodiment of the present invention. Specifically, the control module 601 receives low-voltage electrical power supplied from a remote plug-in transformer 603, and provides sound and motor signals to the mattress structure 605 via an interconnecting cable 607. The control module 601 includes a microcontroller 609 to control timing, motor speed, sounds, displays, and safety factors. For controlling the speed of motor 402, the motor operates on DC voltage derived from conventional power supply 611 under pulse-width modulated control. Specifically, substantially constant drive DC voltage is supplied to the motor in intermittent ON-OFF application at a high frequency rate so that the inertia of the motor integrates the power impulses thus supplied to operate at a speed determined substantially by the ratio of ON time to OFF time. Thus, the microcontroller 609 (e.g., INTEL 80C51FB) performs conventional pulse-width modulation control of the motor 402 via the controller port 613 connected to the gate of a field- effect power transistor 615 in a motor circuit to control the ON and OFF times of conduction of DC current through the motor 402. An additional such field-effect transistor 617 may also be connected in the motor circuit for fail-safe operation via continuous conduction of transistor 617 controlled in conventional manner through active states without error conditions being detected by the microcontrolled 609. Also, the Hall-effect sensor 170 or 452 in various embodiments may be used to control the pulse-width modulation of power supplied to the motor 402. Thus, if the intervals between sensed magnetic positions on a reciprocating link or rotating gear increase, then the ON periods of power supplied to the motor 402 are increased by microcontroller 609 to speed up the motor 402. Similarly, if the sensed intervals decrease, then the ON period of power supplied to the motor 402 decrease to reduce its speed. In this manner, the motor may be operated under feedback control to compensate, for example, for excessive or off-center loading of the mattress pad 108 and motion platform 104 in order to regulate the motor speed within safe operational limits. The microcontroller 609 also controls sounds generated by transducer 110 in response to signals supplied thereto via the audio generation circuit 619 from output port 621 of the microcontroller 609. This port supplies pulse-width modulatable signals to a low-pass filter 623 that may have a cut-off frequency set at two or more orders of magnitude lower frequency than the frequency of the pulse- width modulation. Thus, by altering the pulse-width modulation of the supplied signal relative to the cut-off characteristics of the filter 623, its output varies as a function of the pulse- width modulation of the applied signal from port 621, and may be characterized as producing an output voltage that is representative of an ON-OFF modulation ratio. Such modulation may be performed in conventional manner as a result of controlling signals stored in ROM 625 of the microcontroller 609. For example, actual intrauterine sounds such as heartbeat, gurgitation, respiration, and the like, may be digitized and stored in ROM 625 to provide controlling signals for modulating the pulse widths applied to the filter 623 to provide changing signal levels corresponding to the stored, digitized sounds. Randomly or manually-selectable sounds may be reproduced in this manner via output signals 624 applied to transducer 110 in the manner described above. For fail-safe operation of the mattress structure, the microcontroller 609 may be connected to monitor numerous signals, sequences, voltage levels, and the like, to indicate error conditions on display 627 in conventional manner if monitored conditions are not within selected parameters. Specifically, the pulse-width modulatable signal at output port 629 of the microcontroller 609 may be sensed by LED driver 631 to yield specific logic outputs to drive the output display 627 to indicate numerous operating condition or error-condition codes, and to vary the luminous intensity of the display 627 and the light sources 628 that illuminate the day and night selectors 157, 159. To minimize control signals, the alphanumeric display digits 627 and the four indicators 628 for day, night, start and stop may be multiplex controlled at about 50 Hz refresh rate. For example, a two-digit display 627 and four indicators 628 in proximity to input control switches or keys 631 may be operated, for example, on a time-shared sequential basis at about 50-60 Hz repetition rate to avoid perceivable flicker, all under control of signal supplied at output port 629. Thus, input keys 631 for entering an infant's age (in weeks) may be indicated on display 627 in conventional manner, while start or stop, and night or day indicators 628 are energized periodically in time-shared manner to indicate the operating conditions of the mattress structure 605. An Electronically-Erasable Programmable Read-Only Memory (EEPROM) 633 such as model 24C02 stores non-volatilely the values of certain program variables and manufacturing information (e.g., serial number, hardware and software revision numbers, date of manufacture, and the like) after power is removed from the control module 601. A test connector 635 for receiving appropriate factory-oriented control signals for application to the Universal Asynchronous Receiving/Transmitting (UART) port 637 may be used to store such information under control of microcontroller 609 into the EEPROM 633 for later historical tracking or servicing of each mattress structure. A portion of the EEPROM 633 may also be operationally accessed for storing accumulating cycle counts, age of an infant, gain control for sound level from transducer 110, and the like, all under control in conventional manner by microcontroller 609 which operates on a vibrating quartz crystal clock or time base 639. The clock frequency (typically 16 MHz) may be divided down for one or more timers 641, 642, 643 for such functions as tracking time of day to switch automatically between night mode and day mode, at appropriate times, and accumulating infant age, and controlling intermittent intervals of sound and motor operations that vary in day and night modes as a function of infant age, and the like, all in conventional manner under control of microcontroller 609. Data may be stored redundantly in EEPROM 633 in, say, three identical copies for access and read-out in multiple copies which may all be compared for idempity via conventional checksum operations. In the event that all copies of retrieved stored data are not identical, majority logic may be used in conventional manner to establish the correct data and to correct and update the inconsistent data in storage. In addition, the EEPROM 633 may store a calibration or gain factor for normalizing or standardizing the sound level from transducer 110. The Hall-effect sensor 170, 452 verifies proper motor operation against runaway or overloaded stall conditions by generating a periodic interrupt signal under proper operation. This can be useful in a conventional digital feedback scheme for comparison, for example, against a lapsed timer to determine motor speed by the interval between consecutive interrupts thus generated. Also, the motor 402 may be started up and slowed down to a stop through multiple ranges of speeds to eliminate sudden speed change that may be startling to an infant by automatically altering motor speed after each (or multiple few) such interrupts thus generated each time the magnet 450, 171 passes the associated sensor 452, 171. And, the motor 402 may be powered down through such speed changes in the manner previously described to halt operation completely at selected orientations of link 412 and barrel cam 416 (for example, bed horizontal). For example, a timed determination of powering down the motor under logic control of microcontroller 609 initially reduces the ON-OFF ratio of signal supplied to the motor to a level that assures continuous low-speed motor operation under all expected loading conditions. Several interrupts may be generated in the manner discussed above to assure continuing low-speed (and lowest-speed) motor operation. Then, due to selective angular positioning of a magnet 450 and sensor 452 relative to the crank 409 and cam 416 orientations, the motion platform 104 and mattress pad 108 supported thereon may be stopped at approximately horizontal (upon the next sensor signal) until next operations of the motor 402 are required. As thus horizontal between motion operations, the motion platform 104 and the base plate 112 may be locked together in the manner as described above by setting the locking devices 456. The EEPROM 633 may be used to store non-volatilely the user-oriented data of accumulating counts of sensor signals as an indication, for example, of the number of flexes undertaken by the flexures 106. The EEPROM 633 may similarly store manufacturer's-oriented data, for example, the maximum allowable number of accumulated sensor signals to enable shut-down of the mattress structure against potentially injurious failures. The stored accumulating counts and the manufacturer's stored maximum allowable count can be compared in the microcontroller 609 to inhibit further motor operation in conventional manner. Referring now to the flow charts of Figures 25A-25M, there is illustrated one routine by which the microcontroller 609 controls selected operations of the mattress structure. Specifically, upon power up, conventional initializations 701 of memory registers, annunciators, data ports, data entry keys and buffers, and the like, may occur under control of microcontroller 609, followed by operation according to the illustrated sequence of steps and events. Specifically, the user's EEPROM parameters are read 703 (e.g., for excessive cycle count, sound volume setting, infant age, and the like) to generate a heartbeat sound 705 and energize 707 the indicator lights 628. Thus, if the mattress structure is to operate in day mode 711 or night mode 713, as set by the user, then the appropriate DAY-NIGHT indicators 628 are turned on 712, 714, and the user-set conditions are then determined 715 to turn on 716, 718 the appropriate ON-OFF indicators 628. The infant's age may be set 720 by the user via keys on the control panel 629, and an initialized warning flag (upon all initialized conditions and sensed parameters occurring within ranges) may be set 721 in preparation for starting 723 the motor-powered movements. If a shutdown flag is detected 725, for example, due to motor drive signals 727, then safety shutdown is initiated. Otherwise, a warning flag is next detected 729 to initiate safety shutdown if any sensed operating parameter (e.g., power supply voltage) is out of acceptable range. Under acceptable sensed operating conditions, user-actuated start key will initiate motor operation 731 , unless a user-actuated stop key is actuated 733. The DAY or NIGHT mode may be set 735, 737, and the infant's age may be entered 739. If the motor is to be operated, the interval since last motorized motion is sensed, and if enough time has elapsed (typically, a few minutes) 741, a flag is set 743 to initiate a new motion cycle. Motor speed, and heart rate sound and volume may be set 745 to initiate a new cycle 747 of motor-actuated motion and sound activities, with associated updates installed 749 to control motor speed, heart rate, and sound volume during latest intermittent operating cycle. As a new intermittent cycle of motion and sound proceeds, the operating conditions are checked 751, including against timing 753 of detected Hall-effect signals, to effect control 755, 756, 757, 758 of motor speed at calculated speed for the setting of DAY or NIGHT operation. Similarly, the sound volume is set 759, 760, 761 at target values (e.g., for age of infant, and DAY or NIGHT operation). Also, the heart rate of sound is set 762, 763, 764 and the operational settings are then updated 765 to the current operating conditions. Thereafter, motor operation is checked 767 throughout the intermittent operating interval until time-out of the current operation interval, or user actuation of a stop key. Motor operation may be initialized, as upon initial power on, by setting the motor speed to zero, or 0 percent pulse width modulation 771. Thereafter, motor speed may be controlled at speeds determined by the pulse- width percent modulation of the ON to OFF ratio 773, as required for desired operating conditions, loading conditions, and the like. As the motor 402 is energized for a cycle of motion, the operating conditions are tested 775 to determine whether the speed is lower 777 or higher 779 than extreme conditions will allow to determine whether safety shut down 781-783 should be initiated. Motor speed may be determined on the basis of the time intervals 785 between occurrences of signals generated by the Hall sensor 452, 171. The occurrence of a Hall sensor signal facilitates calculating the average speed as a function 787 of the time interval lapsed since the last Hall sensor signal, initiates an update of the latest time of occurrence (from which to calculate next time lapse and average motor speed), and increments the accumulating cycle count, and (if the maximum cycle count has not been exceeded 793 and if optional warning levels of accumulated cycle counts have not occurred 795), the accumulated cycle counts (in 2 byte increments) may be updated 795, 797 in the EEPROM 633, and the time of the last trigger may be moved up 799 to avoid errors in controlling the motor. Such motor control may continue until a programmed, aperiodic interruption in the movement occurs by time-out or the current motion cycle (for DAY or NIGHT operation over periods of time that may be inversely proportional to the infant's age), or a manual interrupt via STOP switch 629 is entered. Therefore, the environmental transition system provides a smooth transition from the intrauterine environment to an extrauterine environment by providing to an infant or occupant stimulating motion and sound that can be programmed conveniently to vary selected parameters representative of the distinctive environments over a programmed time period.

Claims: We claim: 1. An actuator mechanism for a mattress structure including a rotatable element coupled to actuate a portion of the mattress structure through predetermined movements in response to rotation of the element, the actuator mechanism comprising: a shaft on the element disposed to rotate about a central axis within a mating bearing; a metal frame including an aperture therein having sidewalls longer than the thickness of the metal frame, and formed via rolling the metal frame laterally through the aperture to integrally form with the metal frame the mating bearing of elongated bearing surface that terminates at an edge thereof that is spaced from the metal frame; a shoulder on the shaft of the element disposed adjacent said edge; and a flange upstanding on said shaft of the element at a spacing from the central axis greater than the thickness of the metal frame forming the mating bearing and protruding from said shaft to terminate adjacent an underside surface of the metal frame for referencing the element axially along the central axis with the shoulder against said edge and the upstanding flange against the underside surface of the metal frame for increased combined surface area of contact between the edge and shoulder and flange and underside of the metal frame. 2. The actuator mechanism according to claim 1 comprising: an eccentric crank disposed on said shaft and a link coupling the crank and the portion of the mattress structure for imparting translational movement thereto in response to rotation of the element; a motor supported with respect to the metal frame and coupled to the element to rotate the element in response to rotation of the motor; and a cam disposed on the metal frame to rotate in response to rotation of the motor, and coupled to the portion of the mattress structure for imparting thereto an oscillatory rocking movement about an axis aligned in the direction of said translational movement of the portion of the mattress structure. 3. The actuator according to claim 2 comprising: a rocker arm coupled between said cam and said portion of the mattress structure for transferring motion about the cam in response to rotation thereof to said rocking motion of the portion of the mattress structure, said rocker arm including a pair of extensions coupled at a location intermediate the length of the rocker arm for longitudinal extension and relative rotation of the extensions about an auxiliary axis substantially parallel to the central axis ; a pair of protrusions oppositely disposed on each extension substantially about the auxiliary axis in engagement at the minimum longitudinal extension of the extensions; resilient means disposed between the extensions to resiliently retain the extensions in minimum extension with the pairs of protrusions resiliently urged into engagement for force transferred by the rocker arm below a selected limit, and for enabling relative longitudinal extension and rotation of the extensions about one or other of mating pairs or protrusions in response to force transferred by the rocker arm in excess of the selected limit. 4. The actuator mechanism according to claim 2 comprising: a worm gear on the motor and a helically-cut gear on said element disposed to engage the worm gear for rotating the element engaged therewith in response to rotation of the motor. 5. A motion platform of selected surface area supported and actuated for predetermined movements relative to a base plate at an average elevation therefrom for supporting an occupant on the platform during the movements, the motion platform comprising: an actuator mechanism disposed between the base plate and the motion platform for actuating the motion platform through the predetermined movements; a plurality of locking elements disposed at locations over the area of the motion platform intermediate the base plate and the motion platform for selectively inhibiting motion of the motion platform relative to the base plate, the locking elements each including a cylindrical element disposed with a lower end thereof in the base plate for rotation therein, and including an upper end of the cylindrical element selectively positionable adjacent the motion platform in response to rotation of the cylindrical element relative to the base plate to selectively inhibit movement of the motion platform with the cylindrical elements rotated to position between the base plate and the motion platform, and to permit the predetermined motion of the motion platform in response to rotation of the locking elements to an orientation of the upper ends thereof remote from the motion platform. 6. The motion platform according to claim 5 in which the locking elements each include a protrusion on the upper end thereof for mating alignment with a protrusion from an adjacent surface of the motion platform in one rotational orientation of the locking element within the base plate, and for positioning out of alignment with the protrusion from the adjacent surface of the motion platform in another rotational orientation of the locking element within the base plate. 7. A controller for a motor-driven actuator for a mattress structure, the controller comprising: a source of power for actuating the drive motor and including a controllable switch; and a processor coupled to the switch for selectively turning on and turning off power applied to the motor at a rapid rate to control speed of the motor in response to the ratio of on to off of the switch. 8. The controller according to claim 7 comprising: an actuator coupling the drive motor to a movable portion of the mattress structure for actuating the movable portion through a predetermined cycle of motion in response to rotation of the motor; a sensor disposed on the actuator to apply a control signal to the processor in response to a cycle of motion, said processor responding to the time interval between control signals applied thereto from the sensor to alter the ratio of on to off of the switch to modify the speed of the motor during a subsequent cycle of motion. 9. The controller according to claim 8 in which the processor alters the operating speed of the motor from a selected speed to stopped by decreasing the ratio of power on to power off applied to the motor through said switch for operating the motor at an intermediate speed during which the sensor applies control signals to the processor over longer time intervals, and the processor ceases application of power to the motor at an orientation of the actuator for which the sensor is aligned at a selected position in the cycle of motion. 10. The controller according to claim 8 in which the processor terminates application of power to the motor under conditions during cycles of motion for which the control signals recur at time intervals longer than one interval limit, or shorter than another interval limit for safe shutdown of power applied to the motor during operating speeds not between speed limits corresponding to said one and said another interval limits. 11. The controller according to claim 7 for an occupant of the mattress structure, including a sound transducer disposed to supply sound to an occupant of the mattress structure, and wherein said processor comprises a control channel for sound generation including a low- pass filter coupled to receive a pulse-width modulated (PWM) output from the processor at an output thereof, said filter including a cut-off frequency substantially lower than the rate of PWM output from the processor for supplying at the output of the filter a signal having an amplitude indicative of the ratio of the PWM output from the processor supplied thereto; and the output of the filter is supplied to the sound transducer for supplying sounds therefrom to an occupant of the mattress structure that are representative of variations of pulse width of output from the processor about a median modulation value. 12. The controller according to claim 11 in which the processor stores selected sounds in memory for selection and recall for modulating the pulse- width of output from the processor supplied to the filter. 13. The controller according to claim 12 wherein the selected sounds are stored digitally in memory at addressed locations for access therefrom to modulate the pulse width of output from the processor supplied to the filter. 14. The motion platform according to claim 5 comprising: a spring element for each locking element disposed to limit rotation thereof between selected angular positions. 15. The motion platform according to claim 14 in which the spring element for each locking element is integrally formed therewith as a cantilevered spring disposed to limit the angular positions of the locking element to locked and unlocked positions. 16. A membrane control panel including a plurality of manual actuators and comprising: a surface layer including text designations thereon for each of the plurality of manual actuators; a switch member disposed beneath each actuator to form an electrical connection in response to manual depression of the actuator; and a light source disposed beneath each actuator for illuminating through the surface layer substantially in the region of the actuator. 17. A membrane control panel according to claim 16 comprising at least the surface layer of flexible sheet material, and a base layer including conductors thereon, and a flexible intermediate layer disposed between the base and surface layers with conductors thereon arranged to engage conductors on the base layer for forming normally-open switches that are actuatable in response to force applied to an actuator region on the surface layer for forming an electrically conductive circuit including the conductors on the base layer and conductors on the intermediate layer. 18. The controller according to claim 7 comprising: memory module coupled to the processor and including manufacture data and operational data stored therein for access and display in response to selected signals applied to the processor.

Inventors: FINKELSTEIN JEFFREY I, JAMIESON JOHN W, SMITH ROBERT J, FINKELSTEIN, JEFFREY, I., JAMIESON, JOHN, W., SMITH, ROBERT, J.
Applicants: INFANT ADVANTAGE INC, INFANT ADVANTAGE, INC.
Application year: 1997
Main classification: A47C
IPC codes: A47C17, A47C23, A47D9