MOVEMENT ACTUATOR

Abstract: An actuator (1) for providing variable periodic movement simulating motion in response to signals. A speaker is provided simultaneously to relay the signals in the form of appropriate sounds. The invention further relates to an apparatus incorporating the actuator which provides to infants motions and sounds which are known to induce sleep.

Description: MOVEMENT ACTUATOR This invention relates to an actuator for use in applications where a small, variable periodic movement is required, such as in motion simulators, animation controllers and stimulation devices. A particular application of the actuator is in a device designed to induce sleep in infants. Actuators in common use in such applications are complicated with many moving parts. Their response to control signals may involve a delay, and programming of the regular periodic motion involves complex control circuitry. According to the first aspect of the invention there is provided an actuator comprising a housing and a movable insert, wherein the housing comprises a substantially cylindrical ring magnet having a central bore, first and second radially planar end surfaces, a steel plate attached to said first end surface of said ring magnet and a pole piece attached to said steel plate and extending axially inside said ring magnet. Preferably the moveable insert comprises an insulating coil former wound with insulated wire. Preferably the insulating coil former comprises a hollow cylindrical portion adapted to fit over said pole piece and first and second flange portions at each end of said cylindrical portion extending outwardly in a radial direction. Preferably said first flange portion is adapted to fit inside the central bore of said ring magnet. Preferably said second flange portion comprises a continuous cap plate closing a hollow end of said cylindrical portion. The movable insert may be supported by a flexible diaphragm attached to said cap plate. The actuator may further comprise electrical or mechanical damping means. Preferably the actuator further comprises an electrical circuit comprising a power supply unit, control unit and switching unit. Preferably the control unit is adapted to control the current in said coil in accordance with a control signal. Said control signal may be an audio signal, a pre- programmed signal, an electronically stored signal, a mechanically input signal or a movement signal. According to a first preferred embodiment of the invention the housing comprises a plurality of substantially cylindrical ring magnets arranged next to each other to form an elongate cylinder having a central bore, the insulating coil former being wound with insulated wire over a portion of its length. Preferably the actuator further comprises control means to reverse the current flow within the coil depending on the position of the coil in relation to the poles of the ring magnets . According to a second preferred embodiment of the invention the housing comprises a plurality of substantially cylindrical ring magnets arranged next to each other to form an elongate cylinder having a central bore, the insulating coil former being wound with a plurality of coils of insulated wire, each coil extending over a length corresponding to the height of a ring magnet. Preferably the actuator further comprises control means to vary the current flow within each coil in sequence. According to a second aspect of the present invention there is provided a sound and motion apparatus comprising a control unit, an actuator comprising motion imparting means responsive to audio signals and audio transmission means, wherein the control unit is adapted to control said motion imparting means in response to audio signals and to play said audio signals through said audio transmission means. Preferably said sound and motion apparatus comprises an actuator in accordance with the first aspect of the present invention. According to a third aspect of the present invention there is provided an apparatus to promote sleep in infants comprising a base member adapted to accommodate an infant carrying device and motion means connected to the base member adapted to impart motion to the infant carrying device. Preferably said apparatus comprises a control unit. Said apparatus may include remote operation means . Preferably the apparatus further comprises audio transmission means. Preferably said motion means comprises a base unit positioned between the base member and the ground, said base unit comprising an actuator adapted to impart motion to the base member and hence to the infant carrying device. Preferably the base unit comprises suspension means to support the base member. Preferably the base unit further comprises said control unit. Preferably the actuator is operated by control signals. Preferably- the control signals are audible signals. Said audible sounds may be replayed through the audio transmission means of the apparatus. Preferably the actuator is in accordance with the first aspect of the present invention. Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:- Figure 1 shows an actuator comprising a ring magnet with an insulating coil former wound with a coil of insulated wire; Figure 2 shows a schematic circuit layout for a control circuit for the actuator; Figure 3 shows an actuator having stacked ring magnets for greater movement; Figure 4 shows an actuator having stacked ring magnets and stacked separate coils for greater movement; Figure 5 shows an alternative embodiment of an actuator which can be used to provide feel in a feed back circuit; Figure 6 shows a circuit diagram for a power supply unit; Figure 7 shows a circuit diagram for the coil drive circuit; Figure 8 shows a plan of the infant sleep inducing apparatus of the third aspect of the present invention; Figure 9 shows a front elevation of the apparatus of Figure 8; Λ Figures 10 and 11 show the circuit diagram for the electronic circuit of the apparatus of Figure 8. Referring to the drawings, an actuator generally designated 1 comprises two essential components together with associated electrical and electronic control circuits. The first component is a ring magnet 3 with one end plate 4 and a concentric pole piece 5 of steel as the magnetic circuit. The ring magnet may alternatively comprise a plurality of concentric ring magnets 23,33. As shown in Figure 3, the pole piece 5 can be made with a variety of pole faces to provide the magnetic field required for a particular application. The second component is an insulating coil former 7 wound with insulated wire, as a coil. The thickness of wire and number of turns are determined by the application and the desired voltage. The coil former 7 surrounds and fits over the central pole piece 5 and is surrounded by the magnet 3. The coil former 7 is free to move up and down in the magnetic circuit. The control signal for the actuator can be of audio or sub-audio frequencies. The actuator can be driven by standard audio sound tracks. The signal may be derived from tape, ROM, RAM, or other sources, and can be of sinusoidal or square wave form, or of more random wave form as required. A method of support and location for the moving part is by flexible diaphragm 8. Motion induced by this primary assembly is dependent on the input signal which can be damped electronically or by mechanical shock absorbing devices, such as mechanical or air springs. Two or more actuators can be mechanically arranged to provide load sharing and/or a complexity of motions. As an example the actuators can be arranged in circular, linear or diametric patterns. As shown in Figure 2, the driver circuit is made up of one or more MOSFETs, protection diodes, and a means of providing amplification of signal to drive the MOSFET gates. Figure 6 shows the circuit diagram for the power supply unit for this actuator, whilst Figure 7 shows the coil drive circuit in greater detail. The actuator 1 can be used in many applications requiring small movement and vibration, both regular and irregular, such as: (a) Vibration/movement in a virtual reality application. The ability to produce small irregular movements in a set way may be used to enhance a sensation of reality; (b) Cinema seating; (c) Home video seating; (d) Vibration and small movement in children's rides or arcade games; (e) Vibrating, separating and stirring/mixing applications; (f) Medical and therapeutic applications; (g) The introduction of programmed movement into simulators both large and small, such as vehicle or aircraft simulators; (h) Providing power at resonant frequency; (i) Providing an effective resonant frequency detector; (j) Providing feel in a feedback circuit, where an operator needs to be able to feel the amount of force that is being applied at a remote location. This example is shown in the actuator 35 of Figure 5, where the cap piece 36 is supported by springs/suspension spheres 9; Similarly, an actuator according to the present invention can be used as a programmable damper of vibration when used in conjunction with a feedback circuit. By using three individual units, an actuator according to the invention can be used as a self levelling unit. A particularly useful application for the actuator is in an apparatus to induce sleep in babies and small children. Apparatus for this purpose consists of an assembly 40, a speaker unit and a key. The assembly 40 shown in Figure 8, which in use sits on the floor, comprises a lower moulding 45. The lower moulding 45 houses a central cylindrical actuator 41, four compression springs or suspension spheres 44, a printed circuit board 42 and electronics components, a transformer 43 and a control panel 48. A socket is fitted for the connection of the speaker unit. The speaker unit is placed remote from the assembly, within earshot of a user. A fixed mains cable with an integral mains plug is attached to this unit. This is fitted with an appropriate fuse. The apparatus is operated by mains power and draws less than 200 watts. The lower moulding 45, with the exception of the control panel 48, is covered by an upper moulding 46. This upper moulding 46 is the motion inducing surface. The control panel is operated by means of a key unit. The key unit is a plastic encapsulated magnet. The key is used by holding it in the correct orientation against the required area of the control panel 48. The control panel 48 comprises reed switches which are actuated by the magnet. This is a safety feature to prevent tampering by children and to provide a smooth surface which is easily cleaned. In the alternative, the control panel has manually operated switches . The assembly 40 is operated by placing the front wheels of a baby buggy or pram in the dished sections 47 of the upper moulding 46. Alternatively, placing adaptor pieces in the dished sections 47 allows a carry cot to be placed on top and utilize the apparatus. These adaptor pieces are provided separately. A first end of each adaptor piece is adapted to be accommodated in the dished section of the upper moulding 46. A second end of each adaptor piece is adapted to accommodate a non- wheeled child carrying device, such as a carry cot. Once the buggy, pram or carrying cot has been placed on the assembly 40, the speaker plugged in and located in the required position and the mains lead plugged into the wall socket, the child is placed in the buggy. The apparatus is switched on by placing the key over the programme 49 50 to be selected for one second. The key is then placed over the volume up position 51 until the sound is at the required level. This is repeated with the motion level up position 52 until the motion is at the required level. Additional controls are provided to superimpose a rhythmic motion over the motion provided by the programme selected. Examples of programmes available at present include car simulation and womb noise. These have distinctive motions which accompany the sounds selected. It is also possible to use the rhythmic (rocking) motion control level in conjunction with the playing of a child's favourite tune. The unit remembers these set levels for the next occasion that it is switched on. The motion controls require to be adjusted for differing weights of baby to obtain optimum performance. The apparatus is controlled by a timer, which switches it off automatically after a preset period. In a particular version, the unit allows the sound and motion to reduce gradually over time before switching off. This reduces the possibility of the child being reawakened by sudden cessation of motion and sound. The actuator 41 consists of a ferrite ring magnet, steel end plate and central pole piece, which is attached to the lower moulding 45. The former consists of a bobbin of non magnetic and electrically insulating material wound with a coil of enamel insulated copper wire, which is encapsulated in resin to prevent the ingress of moisture. This former is attached to the under side of the upper moulding 46, located around the central pole piece and surrounded by the ring magnet. Two insulated wires from the bobbin are led to the electronic control components mounted in the lower moulding 45. The suspension of the upper moulding 46 is by means of four coil compression springs or four rubber suspension spheres 44. If springs are used, these are secured to the lower moulding 45. If spheres are used these are located in the same position as the springs would be, but are unsecured. The transformer 43 and associated components are located on the lower moulding 45. The transformer 43 provides an isolated low voltage supply to the control electronics . The printed circuit board 42 is located in the lower moulding 45 and carries the solid state recordings, the waveform generator, timers, timebase generator, solid state potentiometers, buffer, audio amplifier, actuator 1 drive components and associated components. It is intended that these components will be reduced to one or two custom chips for production purposes . The control panel 48 housed in the lower moulding 45 comprises reed switches. These reed switches are actuated by the magnetic key. As shown in Figures 10 and 11 taken together, the electronic circuit for the apparatus consists of two solid state recording chips 100 with prerecorded sounds and motion waveforms. These are controlled by independent, toggle on/off reed switches 102 and associated timing circuits provided by the two 6047 chips. This circuit controls the running time, and works as an interlock to prevent both solid state recordings being actuated at the same time. An optional fade out unit 106 is also shown. The waveform generator 108, provided by a 8038 chip, is controlled by a digital potentiometer. The digital potentiometer is controlled by magnetically operated reed switches. These reed switches vary the frequency of the waveform. Further digital potentiometers are controlled in the same way to vary sound levels, actuator response and waveform generator output. The sound is sent to a single chip amplifier 110 and then to the external speaker 112. The output for the actuator is routed via a driver chip and then to a MOSFET which controls the voltage applied to the actuator coil. This is as shown in the schematic layout of Figure 2. As previously outlined, the actuator of this invention may be used in many other applications. Fuller examples include: (a) Vibration/ movement in a virtual reality application. The ability to produce small irregular movements in a set way can be used to enhance a sensation of reality. Motion can be imparted through a grabrail or a base platform. (b) Cinema Seating. The motions of the seats is controlled by a sound track, either directly using the sound track itself, or by programmed waveforms embedded within it. A control circuit is required to interpret and amplify the signal to the seats. (c) Home video seating. The motion of a seat is controlled by a film sound track, either directly using the sound track itself, or by programmed waveforms embedded within it. A control circuit is used to interpret and amplify the signal to the seats. (d) Vibration and small movement in children's rides and arcade games. Actuators of the present invention are placed under each foot or "wheel" and controlled by a programmed soundtrack to provide variable motion. This repla -is the bulky mounts of existing children's ride toys. (e) Toys such as teddy bears and parrots which can 'talk' to a person using an electronic audio transmittal device are already known. The mechanism of the invention is used to animate the lower jaw or beak of the toy to provide added realism. This application extends to use in larger puppets for interactive display at trade exhibitions, in arcade toys, etc. (f) By coupling a mechanical linkage to both magnet and coil of the actuator, a device can be made which can 'walk' with a shuffling gait. (g) Vibrating, separating and stirring/mixing applications. A laboratory mixer can have its motion described in amplitude, acceleration and frequency to provide the optimum motion required by the substance being mixed. (h) The actuator of the invention can be used as a prime mover in a vibration table, where small components need to be subjected to a testing vibration programme to ensure the mechanical and operational stability of the component when in service. It may be particularly useful when small movements in the audio or sub audio frequencies are required. (i) The actuator of the invention may be used in conjunction with cleaning or degreasing baths or the like to provide the optimum cleaning frequency for loosening a particular contaminant. (j) Medical applications. An actuator may be laid over, wrapped round or placed under a patient to stimulate muscle movement and blood flow, and promote joint mobility. (k) Two units may be built into a pillow and harness arrangement for strapping to the back of a cystic fibrosis patient. This has the advantage that an individual can control his own treatment, dialling the most productive frequency for him, rather than having a parent or helper thump his back as is current procedure. (1) Therapeutic applications. A unit may be built into a chair having supported, gel filled compartments, which moves/massages an occupant to the accompaniment of relaxing music. As a refinement, the gel compartments could be heated. (m) Using actuators according to the invention, programmed movement may be introduced into simulators of any size. In some instances the actuators could substitute for hydraulics. The units can be built into the body of a simulator (eg cockpit wall) to provide finely tuned vibrations that replicate eg engine vibration, lightning strike, fine turbulence and noise. (n) Units are suitable for powering at resonant frequency. Units can be used to amplify motion in the resonant phase where large motion is required from a small input. (o) An actuator according to the invention makes an excellent resonant frequency detector. (p) Units can be used to provide feel in feedback circuit where programmable force is required, such as robotic mechanical hand. An operator can feel how much force is being applied when, for example, trying to life an egg. (q) Units can be used to create a composite self levelling unit for a component that needs to be quickly adjusted when in use (whilst a mechanical mechanism catches up) . This requires three units. (r) Using a feedback circuit, units according to the invention can be used as a programmable and interactive damper in moving components . (s) A unit can be used as a programmable 'stick shaker' in aircraft to warn of impending stall conditions or, with a different motion, to warn of any other condition of which pilots require to be made aware. In a similar fashion a unit can be built into any control seating to warn an operator of an alarm condition. (t) A unit can be built into a clock mechanism to provide an ornamental view of a different type of working mechanism. (u) A unit can drive a device which will help develop a baby's sleeping pattern by simulating the somnambulant effects of a car, womb music, heartbeat, footfalls, or other sound source as required. (v) A unit can be used as an activator at the end of a flume tank to provide wave action for model ships. The wave action will be readily adjustable in amplitude and frequency. Improvements and modifications may be made to the above without departing from the scope of the present invention.

Claims: CLAIMS 1. Actuator comprising a housing and a movable insert, wherein the housing comprises a substantially cylindrical ring magnet having a central bore, first and second radially planar end surfaces, a steel plate attached to said first end surface of said ring magnet and a pole piece attached to said steel plate and extending axially inside said ring magnet. 2. Actuator according to Claim 1 wherein the moveable insert comprises an insulating coil former wound with insulated wire. 3. Actuator according to Claim 2 wherein the insulating coil former comprises a hollow cylindrical portion adapted to fit over said pole piece and first and second flange portions at each end of said cylindrical portion extending outwardly in a radial direction. 4. Actuator according to Claim 3 wherein said first flange portion is adapted to fit inside the central bore of said ring magnet. 5. Actuator according to Claim 3 or 4 wherein said second flange portion comprises a continuous cap plate closing a hollow end of said cylindrical portion. 6. Actuator according to any preceding Claim wherein the movable insert is supported by a flexible diaphragm attached to said cap plate. 7. Actuator according to any preceding Claim wherein the actuator further comprises electrical or mechanical damping means . 8. Actuator according to any preceding Claim wherein the actuator further comprises an electrical circuit comprising a power supply unit, control unit and switching unit. 9. Actuator according to Claim 8 wherein the control unit is adapted to control the current in said coil in accordance with a control signal. 10. Actuator according to Claim 9 wherein said control signal may be an audio signal, a pre-programmed signal, an electronically stored signal, a mechanically input signal or a movement signal. 11. Actuator according to any preceding Claim wherein the housing comprises of plurality of substantially cylindrical ring magnets arranged next to each other to form an elongate cylinder having a central bore, the insulating coil former being wound with insulated wire over a portion of its length. 12. Actuator according to Claim 11 wherein the actuator further comprises control means to reverse the current flow within the coil depending on the position of the coil in relation to the poles of the ring magnets. 13. Actuator according to any one of Claims 1 to 10 wherein the housing comprises a plurality of substantially cylindrical ring magnets arranged next to each other to form an elongate cylinder having a cental bore, the insulating coil former being wound with a plurality of coils of insulated wire, each coil extending over a length corresponding to the height of the ring magnet. 14. Actuator according to Claim 13 wherein the actuator further comprises control means to vary the current flow within each coil in sequence. 15. Sound and motion device comprising a control unit, an actuator comprising motion imparting means responsive to audio signals and audio transmission means, wherein the control unit is adapted to control said motion imparting means in response to audio signals and to play said audio signals through said audio transmission means. 16. Sound and motion apparatus according to Claim 15 wherein the apparatus comprises an actuator according to any of Claims 1 to 14. 17. Apparatus to promote sleep in infants comprising a base member adapted to be positioned on a support surface, load locating means adapted to at least partially support an infant carrying device, and motion imparting means adapted to impart periodic motion of the load locating means with respect to the base unit and a control unit. 18. Apparatus according to Claim 17 wherein said motion imparting means comprises an actuator acting between the base member and the load locating means. 19. Apparatus according to Claim 17 or 18 further comprising suspension means to support the load locating means with respect to the base member. 20. Apparatus according to any one of Claims 17 to 19 wherein the control unit controls the movement of the actuator in response to audible signals. 21. Apparatus according to Claim 20 further comprising audio transmission means. 22. Apparatus according to Claim 21 wherein said control unit is adapted to play said audible signals through said audio transmission means while simultaneously controlling the movement of the actuator in response to audible signals. 23. Apparatus according to any one of Claims 17 to 22 wherein the apparatus comprises an actuator according to any one of Claims 1 to 14.

Inventors: BAKER CHRIS, HIGGINS JOHN, MACDONALD DUNCAN, BAKER, CHRIS, HIGGINS, JOHN, MACDONALD, DUNCAN
Applicants: BAKER CHRIS, HIGGINS JOHN, KIMERA LIMITED, MACDONALD DUNCAN, BAKER, CHRIS, HIGGINS, JOHN, MACDONALD, DUNCAN
Application year: 1997
Main classification: H04R5
IPC codes: G09B9, H02K41, H04R5