(12)United States Patent
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`Sabo
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`l 1111111111111111 11111 111111111111111 111111111111111 IIIII IIIIII IIII IIII
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`(10) Patent No.:
`US 6,803,744
`Bl
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`( 45) Date of Patent:
`Oct. 12, 2004
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`US006803744Bl
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`(54)ALIGNMENT INDEPENDENT
`AND SELF
`
`ALIGNING INDUCTIVE POWER TRANSFER
`SYSTEM
`
`5,311,973 A * 5/1994 Tseng et al. ................ 320/108
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`
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`5,314,453 A * 5/1994 Jeutter ......................... 607/61
`5,498,948 A 3/1996 Bruni et al.
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`5,536,979 A * 7/1996 McEachern et al. ........ 307/104
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`5,545,191 A * 8/1996 Mann et al. .................. 607/57
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`5,821,728 A * 10/1998 Schwind ..................... 320/108
`5,821,731 A 10/1998 Kuki et al.
`5,923,544 A * 7/1999 Urano ......................... 363/22
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`the term of this ( *) Notiee: Subjeet to any disclaimer,
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`6,016,046 A * 1/2000 Kaite et al. ................. 320/108
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`patent is extended or adjusted under 35
`*eited by examiner
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`U.S.C. 154(b) by 81 days.
`
`Anthony Sabo, 1513 N. Ohio St.,
`(76)Inventar:
`
`Arlington, VA (US) 22205
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`(21)Appl. No.: 09/702,234
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`(22)Filed:Oct. 31, 2000
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`Primary Examiner--Dregory J. Toatley,
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`Jr.
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`(74)Attorney, Agent, or Firm-Samuel Shipkovitz;
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`Laubseher & Laubseher
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`(57)
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`ABSTRACT
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`Related U.S. Application Data
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`on Nov. 1,( 60)Provisional application No. 60/162,295, filed
`An induetive power transfer deviee is provided for reeharg­
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`1999.
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`of includes a plurality ing eordless applianees. The deviee
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`induetors arranged in an array and eonneeted with a power
`(51)Int. Cl.7
`H02J 7/00
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`supply via switehes whieh are seleetively operable to aeti­
`320/108; (52)U.S. CI ......................................... 307/104
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`vate the respeetive induetors. The induetors serve as the
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`(58)Field of Search .......................... 320/108; 307/104,
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`primary eoil of a transformer. The seeondary eoil of the
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`307/150; 336/40, 118, 119, 130, 131
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`transformer is arranged in the applianee. When the applianee
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`is ar ranged proximate to the power transfer deviee with the
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`respeetive eoils in alignment, power is induetively trans­
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`ferred from the deviee to the applianee via the transformer.
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`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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`(56)
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`References Cited
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`U.S. PATENT DOCUMENTS
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`4,374,354 A * 2/1983 Petrovic et al. ............. 320/108
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`4,556,837 A * 12/1985 Kobayashi et al. ......... 320/108
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`28 Claims, 4 Drawing Sheets
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`Page 1 of 12
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`Volkswagen Exhibit 1031
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`U.S. Patent
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`U.S. Patent
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`1
`ALIGNMENT INDEPENDENT AND SELF
`ALIGNING INDUCTIVE POWER TRANSFER
`SYSTEM
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`This application is based on provisional application No.
`60/162,295 filed Nov. 1, 1999.
`BACKGROUND OF THE INVENTION
`The present invention generally relates to inductive power
`transfer devices for charging or powering cordless appli
`CCS.
`Currently, cordless electrically operated devices are
`charged by a Source of electrical energy only when the
`device and Source are connected to one another. Normally,
`the Source includes Some Sort of pedestal to which the device
`is connected before charging may occur. The drawbacks of
`Such an arrangement are Self-evident. For example, when
`working with a cordless drill, it is often necessary to mount
`a battery which must be removed from the drill, or the drill
`itself, on the charger before the charging process can begin.
`If the charger is not kept in close proximity, the drill battery
`must be moved to the charger. The present invention differs
`Significantly from the known prior art wherein the Source
`and devices are Specifically matched to only operate when
`the receiver is mounted on the holder for recharging. The
`present invention provides a novel System for automatically
`charging a device whenever it is placed on a rest Surface
`without a direct electrical connection, regardless of the
`orientation of the device on the Surface.
`
`SUMMARY OF THE INVENTION
`Accordingly, it is a primary object of the invention to
`provide an induction power transfer device for an appliance
`including a housing and a plurality of primary inductors or
`coils arranged in an array within the housing. A circuit
`connects the inductors with a power Supply and a plurality
`of Switches connect each inductor with the circuit. The
`Switches are operable to Selectively activate respective pri
`mary inductors So that when an appliance having at least one
`Secondary inductor is placed on the housing, power is
`transferred to the appliance via a transformer defined by the
`primary inductors and the Secondary inductor.
`According to a further embodiment of the invention, at
`least one of the primary inductors has a longitudinal axis
`arranged normal to the axes of the other primary inductors.
`The housing preferably has a flat top wall beneath which
`the primary inductors are arranged in a plane parallel to the
`wall. An appliance placed on the wall has its Secondary
`inductor inductively coupled with at least one of the primary
`inductors.
`According to a further object of the invention either the
`inductive transformer device or the appliance may include
`an alignment mechanism to assist in aligning their respective
`inductors to maximize power transfer.
`According to another object of the invention, capacitors
`are provided for each primary inductor to balance the
`inductance thereof.
`In accordance with the invention, a user could merely
`place the appliance Such as a cordless power tool, laptop
`computer, or recording device on a table, Shelf or other
`common Storage member and the charging process occurs
`automatically, regardless of the orientation of the receiver
`relative to the charging Source. This would result in the
`appliance being charged whenever it is not in use, rather then
`merely resting on a work table between uses as in current
`practice.
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`The unique assembly of the present invention assures that
`the transfer of inductive power will occur regardless of the
`orientation of the appliance relative to the charging Source.
`To achieve this result, the Source may be configured with a
`number of coils that are arranged in predetermined positions
`that optimize the transfer of power to the appliance for
`certain applications Such as a maximum duty cycle, i.e.,
`power transfer density, or minimum obtrusiveness.
`
`BRIEF DESCRIPTION OF THE FIGURES
`Other objects and advantages of the invention will
`become apparent from a study of the following Specification,
`when Viewed in the light of the accompanying drawing, in
`which:
`FIG. 1 is a front plan view of an induction power transfer
`device in the form of a table in accordance with the
`invention;
`FIGS. 2-5 are circuit diagrams, respectively, showing
`various ways in which a plurality of inductors is connected
`in the induction power transfer device according to the
`invention;
`FIG. 6 is a circuit diagram of the induction power transfer
`device including capacitors for inductors,
`FIG. 7 is a diagram showing the arrangement of inductors
`of the power transfer device and of an appliance to form a
`transformer;
`FIGS. 8 and 9 are front and side views, respectively, of an
`embodiment of the invention being activated by an appli
`ance,
`FIG. 10 is a diagram of a further embodiment of the
`invention including annular contacts thereof;
`FIGS. 11 and 12 are sectional views showing movable
`inductors in an appliance for alignment with an inductor of
`the induction power transfer device;
`FIG. 13 is a diagram showing an alignment mechanism of
`the invention; and
`FIG. 14 is a diagram illustrating a further embodiment of
`the invention for Simultaneously charging a plurality of
`appliances.
`
`DETAILED DESCRIPTION
`The invention relates to an induction power transfer
`device which is operable to charge a cordless battery pow
`ered appliance Such as a hand tool, laptop computer, music
`player, or the like. In its broadest Sense, the invention is a
`universal inductive interface power connection System
`including both a powered “source” and a cordless “receiver”
`which can be used together to transfer power from the Source
`to a variety of receivers for charging the same.
`The induction power transfer device includes a housing
`which may take one of several forms. In FIG. 1, the housing
`comprises a bench or table 2 having a flat upper Surface 4.
`Beneath the Surface is a planar array of inductorS 6 which
`operate as the primary inductors of one or more transform
`erS. AS will be developed below, each inductor comprises a
`coil having a longitudinal axis. A magnetic core may be
`provided for each coil.
`The inductors 6 are connected with an electrical conduc
`tor 8 which in turn is connected with a power supply 10. In
`addition, an electrical Switch 12 is connected between each
`inductor 6 and the conductor 8 so that the primary inductors
`can be selectively activated. For example, in FIG. 1, four
`inductors 6 are shown, but only the first and fourth have their
`Switches closed to Supply power thereto for activation.
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`3
`Resting on the top surface 4 of the table 2 are two
`appliances, namely, a laptop computer 14 having a Second
`ary inductor 16 and a cordless drill 18 having a secondary
`inductor 20. When the secondary inductors 16, 12 are
`aligned with primary inductors of the power transfer table 2,
`power is transferred from the table to the appliances, i.e., the
`laptop computer 14 and the drill 18 via transformers defined
`by the adjacent primary and Secondary inductors. This
`power can be transferred to a battery in the appliance to
`charge the battery in order to power the appliance. Thus, for
`example, as represented by the block 22 in the drill 18 of
`FIG. 1, power from the secondary inductor 20 is supplied to
`a battery. A Switch then activates the motor of the drill for
`operation.
`It will be appreciated by those of ordinary skill in the art
`that the housing may take many shapes. For example, it can
`be formed as an elongated Strip or pad on which an appliance
`may be rested, or a tool belt against which a power tool can
`be Suspended. With the invention, any time an appliance is
`not in use, it can be rested or placed on the power transfer
`housing and recharged owing to the proximity of the primary
`and Secondary inductors.
`Referring now to FIGS. 2-5, the inductors 6 can be
`arranged in various patterns to insure charging of an appli
`ance regardless of the position of the appliance on the
`housing on the power transfer device. In FIG. 2, a plurality
`of inductors 6 are connected in series with a source 10. In
`FIG. 3, Some inductors 6a are arranged with their longitu
`dinal axes normal to the axes of the inductors 6, with all of
`the inductors arranged in the same plane. FIGS. 4 and 5
`show additional arrays of inductors in Series and Square
`configurations, respectively.
`While the drawings illustrate a fixed number of inductors,
`it will be appreciated that the invention is not So limited and
`that any number of inductors may be provided to define an
`array as large as the housing in which it is arranged.
`Preferably, the power transfer device inductors are
`arranged as close as possible to the inside Surface of a
`protective wall of the housing (FIG. 1) which should be thin
`enough not to unduly Separate the Source and receiver
`inductors and thereby diminish the ability to transfer power
`to the receiver resting on the cover. Advantageously, the
`multiplicity of Source inductors is connected in parallel to
`pairs of Supply lines, which pairs of liens extend to the
`power Supply via interposed coil Switches to allow only
`those coils in proximity to the receiver to be Selectively
`energized.
`In an alternative arrangement shown in FIG. 6, the Source
`coil is energized through a single Supply line provided one
`coil lead is connected to the line and the other lead coil is
`connected to a capacitor 24. To maximize power transfer,
`Sufficient capacitance may be needed in Series with each
`inductor to keep the current in phase with the Voltage.
`Accordingly, capacitors are arranged relative to the interface
`when the appliance and the Source are in mating positions So
`as to provide capacitive coupling for additional power
`transfer. Such transfer may be weak relative to the inductive
`transfer generated between the primary coils mounted in the
`Source and the Secondary coils mounted in the appliance.
`AS Stated above, the Source inductors may be oriented
`parallel or normal to the array plane. The inductor coils may
`include a compressed portion extending Substantially paral
`lel to the mating Surface (similar to the flat portion of the
`letter “D” as shown in FIG. 7) to increase magnetic perme
`ation from the Source to the appliance. Alternatively, the coil
`croSS-Section may be customized to follow the contours of
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`the mating Surface to maximize permeation. The coils may
`take the form of an air coil or may have iron and/or other
`material extending through the core to improve transmission
`of the field lines between the Source and the appliance.
`The core of the inductors may be formed of magnetically
`permeable fibers, threads or tubes in air or oil or a binding
`matrix which could consist of a Viscous fluid or elastomer
`either of which could be designed to soften as the air
`temperature around the coil rises. This would result in the
`magnetic core fibers migrating into the most efficient con
`figuration for transmitting power through the interface with
`the appliance, while avoiding the potential inconvenience of
`a fluid filled array. It will be readily appreciated that, by
`choosing a matrix configuration which has Some compres
`Sive Strength when not heated by the presence of an oper
`ating interface, the coils within the cord or other array may
`be protected against crushing when Subjected to transverse
`forces. Alternatively, the core matrix could be fluidized by
`the presence of the electrical or magnetic activity at the
`interface between the Source and the appliance, Such as by
`a magnetic core fiber being non-aligned with the field lines
`of the interface, which tends to generate more heat than an
`aligned core. The fluid core arrangement allows the cores to
`configure themselves into the most efficient configurations
`with respect to any established interface configuration, by
`curving toward the mating Surface end of the coils.
`The inductors mounted in the appliance should be embed
`ded near the Surface of the device that comes in proximity
`with the source pad or table as shown in FIG. 1. For
`example, the inductor coil(s) may be embedded near the
`bottom Surface of a laptop computer for inductively cou
`pling with any Source array mounted in a Seatback tray on an
`airplane, train computer table, etc. This would allow the
`laptop to be recharged while resting or in use. In a similar
`manner, a power tool may include a coil array positioned
`adjacent to a Surface of the tool that would conveniently rest
`on the Source pad, thereby allowing the tool to recharge
`while laid to rest.
`To assure that the appliance will recharge no matter its
`orientation relative to the Source array, it is preferable that
`the appliance include a set or plurality of inductors, i.e.,
`Solenoid coils with Some arranged parallel and Some
`arranged normal to the Surface of the Source pad. When the
`coils are arranged parallel to the Surface, they have a
`dispersion of X-y orientations Such as a tessellated polygonal
`or Square grid, So that at least Some of the appliance and
`Source coils are in alignment with each other to allow
`efficient inductive coupling between the Source and the
`appliance.
`In FIG. 7 is shown a further embodiment of an inductive
`power transfer device 102 for an appliance 104. The device
`102 includes separate coils 106, 108, with the coil 106
`having a magnetic core 110 contoured to the core 112 of a
`secondary coil 114 of the appliance. Each primary coil 106,
`108 also includes its own power source 116, 118 in lieu of
`a Switch for activating the coil.
`Rectification can be provided to each lead from each coil
`in the form of a pair of diodes 120 of opposite polarity on
`each coil lead with the output of each diode feeding the
`appropriate Side of the battery. In this embodiment, each
`increment of power generated in any Secondary coil in each
`inductive cycle caused by the power Supply will be captured.
`For ease of manufacturing, all output leads from the diodes
`of one polarity could go "up, i.e., in the +z direction relative
`to the X-y plane of the array to contact an essentially planar
`buS Such as used in a PC board comprising the inner Side of
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`an appliance array. The other polarity diode output leads
`could go "down, i.e., -Z to a similar bus positioned on the
`outer Side of the receiver cavity.
`It is desirable for the Source coils to only operate when an
`appliance is laid to rest on an item containing the Source
`coils. By preventing the Source coils from continuously
`generating an electromagnetic field, the System would con
`Serve power while eliminating objecti9onable electromag
`netic fields. This result is achieved by the Switches 12 (FIGS.
`2-5) provided So that each Source or primary coil is ener
`gized from the power Supply only when a Secondary coil is
`within effective range and there is Sufficient translational and
`rotational alignment between primary and Secondary coils.
`Referring to FIG. 7, this arrangement can be achieved by
`residual permanent magnetism in the appliance 104 or by a
`Separate magnet 112 associated with each Secondary coil 114
`which operates a magnetic Switch, a MOSFET, or similar
`switch (not shown) to turn the source coil on or off.
`Alternatively, the coils could be Selectively energized by a
`resonance created between the primary and Secondary coils
`which resonance amplifies a tiny residual power flow in each
`Source coil. A further means for controlling energization
`may include a piezoelectric, or other Oscillator in a tuned
`circuit pumped by random vibrations which generates feed
`back amplification when in proximity to a matched
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`oscillator, thus opening a power transistor and/or OP-AMP
`between the coil and Supply line once a threshold is reached.
`The coil switch (including transistor and/or OP-AMP) could
`also be operated by any kind of tag Such as a microchip
`asSociated with each receiver coil which could generate its
`own signal (acoustic, radio, etc.) or respond to a polling
`Signal from a matched device associated with each Source
`coil.
`In the alternative embodiment of FIGS. 8 and 9, a
`continuous source coil 202 with multiple leads or taps 204,
`i.e., at regular intervals going to the Supply line, up to the
`limit of one lead (or tap) per coil going to each side of the
`power supply 208 can be provided. A coil Switch is on every
`lead So that whatever length of Source coil is in range of the
`receiver coil is activated. A continuous integrated circuit coil
`switch (“CICCS") may take the form of a ribbon or strip of
`a magnetoreactive Semiconductor, possibly organo
`polymeric in nature, which goes into its conductive mode
`when in the presence of a magnetic field emanating from a
`Secondary coil 210 in close proximity. In one embodiment,
`a magnetic north responsive CICCS is deployed to be in
`continuous contact with one Supply conductor and each coil
`tap connected to the N-CICCS so that power from the supply
`conductor must traverse the width of the N-CICCS to reach
`the tap. A South (magnetic) responsive CICCS is similarly
`deployed between the coil taps and the other Source con
`ductor. When a Secondary coil with a permanent magnet 212
`as its core is positioned at a position wherein the magnetic
`fields interact, the N end of the core magnet opens the
`N-CICCS and the S end of the core magnet opens the
`S-CICCS, wherein the points of opening of the N-CICCS
`and the S-CICCS are separated by exactly the length of the
`receiver inductor whose core magnet opened the two CICCs,
`forming a circuit from one Supply line to the other Supply
`line that extends through the corresponding Segment of the
`Source inductor coil or a single CICCS could be used in the
`Single lead with a capacitor Scheme. Alternatively, the
`CICCS could be opened by other conventional devices.
`The power Supply 208 for generating the electromagnetic
`field in the source inductor coils may be either AC or
`intermittent DC, such as half-wave rectified. The power
`supply may vary at line frequency (60 or 50 Hz.) or a power
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`Supply with a higher frequency oscillator may be employed.
`The inductive power transfer is proportional to dv/dt, minus
`losses to Self inductance, which increase with increase in
`frequency.
`In another preferred embodiment of the present invention
`shown in FIG. 10, maximum transfer of power is achieved
`by allowing the coils forming either the primary 302 or the
`secondary 304 to move relative to the other set of coils. If
`one set of coils is allowed to move, i.e., to translate as much
`as one-half or more of the intercoil spacing in either the X or
`y direction or both and to rotate as much as one-half of the
`intercoil angle or more in either direction about the Z axis So
`that via an engagement alignment device Such as a core
`magnet the coils or arrayS can achieve maximum alignment
`when forming a coupled transformer. To achieve this result,
`the movable coils or arrayS may be set in a non-conductive
`container or lozenge 306 preferably having an annular
`configuration with connections provided either by flexible
`wires, or by brushes and concentric commutators on the
`lozenge body designed to exclusively contact the appropri
`ate brush. Alternatively, the upper and lower Surface of each
`inductive coil/array-lozenge may functionally Serve as the
`output brushes for the Secondary inductor coils or arrayS,
`which brushes transmit any power generated to the upper
`and lower internal surfaces of the cavity in which the
`inductor coil/array lozenges are free to move transitionally
`and rotationally. These surfaces 308 serve as sliding contacts
`or commutators, collecting power from the Secondary coils
`and Sending it to the device's battery, Switch and end user
`circuitry.
`The Secondary and/or SSource coils could also take the
`shape of flexible coils which are free to bend and migrate
`within a cavity formed in either the Source or appliance
`device. Alternatively, the flexible coil may be free from the
`constraint of any cavity, So as to best align with its mating
`coil. Motion of the coils (within or without their cavities) is
`facilitated by a vibrator which is briefly energized when a
`coil-Switch is opened, with the Vibrations making it easier
`for the coils to migrate into alignment with each other and/or
`by an active seeker mechanism (FIGS. 11 and 12) attached
`to the coil. The vibrator could be periodically energized. It
`and the seeker are also usable with any other form of the
`inductor coils.
`The seeker mechanism 402 is attached to any movable
`Source or appliance inductor which mechanism is designed
`to bring the primary and Secondary coils into ideal alignment
`for inductive coupling. In FIGS. 12 and 13, the appliance
`404 has the movable coil 406. This may be achieved by
`means of a piezoelectric or pieZomagnetic leg 408 extending
`from each side of the movable inductor 406 to contact the
`inner Side of the mating Surface which is designed to fleX
`(under influence of the electric or magnetic flux at the
`interface) in a direction which will move the inductor into
`alignment with the primary coil 410 as shown in FIG. 12.
`The legs may be made of materials of opposite polarity in
`the dorsal and Ventral region to cause lateral motion.
`Furthermore, end portions of the legs may need to have a
`biased grip to engage the mating Surface. Alternatively, the
`lower leg portions may have a coefficient of friction which
`varies with the variations in electric or magnetic fields. AS
`a result, the lower portions of the legs grip the mating
`Surface more Strongly during that phase of the motion which
`would bring the coil into alignment. This may apply to a
`mobile discrete inductor or a flexible inductor which could
`be arrayed in their space in an “S” curve to allow motion of
`the central portion or other arrangement.
`An advantageous form of inductive interface System
`shown in FIG. 13 includes bumps or waffles formed in the
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`exterior surface of the source pad 502, which bumps corre
`spond to locations of a Source coil or array. The bumps or
`waffles would mate with indentations in the cover of the
`appliance coil or array 504a-e So as to provide a simple
`System of aligning the mating coils resulting in high inter
`face efficiency. The System of bumpS and indentations might
`be positioned with one bump located at each end of each
`coil, or a pair of bumps on either Side, or any other Suitable
`arrangement. The Source array is preferred for the bumps, as
`indentations would tend to accumulate Sawdust or the like
`from the workplace which could impede inductive coupling
`efficiency. The ideal System of bumps and indentations is
`envisioned as having the croSS Section of the upper half of
`a Sine wave, So that a receiver array will sit casually on a
`Source array and will tend to rotate and translate under the
`influence of gravity and/or magnetic or other attraction into
`maximum alignment. By proper Sizing and Spacing of the
`bumps into a shape Similar to the Sinusoidal undulating wave
`form of array, a good degree of interoperability may be
`achieved.
`For power tools and other uses requiring larger amounts
`of power, a grooved form of Source and receiver array may
`be employed, wherein the Surface is described by a sinusoid
`undulation (possibly flattened on tops to allow interface with
`flat Surfaced interfaces) with the coils disposed in the convex
`portions of the Sinusoid. This arrangement assures that when
`Sinusoidal powered Source and appliance arrays are located
`proximate to each other, inductive interaction of Source and
`appliance coil arrayS is maximized. Sinusoids could be
`transverse to each other, Such as in a power tool power
`cord/strip So as to facilitate rolling up of cord/Strip, or
`longitudinal (if Such axes are identifiable).
`Another form of inductive interface system formed in
`accordance with the present invention may consist of a
`Source array disposed on the end of an extension cord which
`would engage with a Secondary array disposed on a power
`tool or other device. This could provide power for 100%
`duty cycle even with the heaviest of usage, and yet be readily
`disconnected at any time, merely by manually applying
`tension, or via one of the disengagement devices discussed
`hereabove. Another form of the invention includes a small
`table/toolrest with source arrays in the surface, with the table
`having extendable legs that allow the table to be positioned
`where needed.
`A major feature of the “Universal Inductive Interface
`Power Connection System’ comprising the present inven
`tion resides in the fact that while configurations and densi
`ties of Source and appliance arrayS may be optimized for
`different applications, different Sources and receivers are at
`all times interoperable. For example, a flat Surfaced array
`may be employed with a Sinusoid Surfaced array and Vice
`Versa. As a general rule, the maximum current available for
`power transfer will be a function of interface area, inductor
`density and the coupling efficiency factor. With a Standard
`ized Source coil density, the Secondary array maximum
`Voltage will be a function of appliance coil density, as in any
`transformer.
`Referring to FIG. 14, all forms 602a-d of the source array
`which might be desirable on a job-site or in a home or office,
`would have both a plug 604 for receiving power from wall
`Socket or other source 606 and a Socket 608 or more so that
`other forms of course array may be connected togther to
`provide a broad Spectrum of recharging possibilities. For
`example, a long power cord array could stretch the entire
`expanse of a job-site, providing opportunities along its entire
`length for a modest rate of recharging, and forms of Source
`arrayS. Such as a pad comprising the upper Surface of a shelf
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`US 6,803,744 B1
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`8
`of a work table could be connected to and derive power from
`the conductors of this power cord. This would provide faster
`recharging than otherwise available. It would also provide
`efficient recharging at locations on the job-site of heaviest
`tool use. Source pads or other containers for the Source
`inductor coils employed in the charging System of the
`present invention may advantageously be set upon tables,
`Workbenches, Saw horses, shelves or the like to relieve the
`worker of the current necessity of bending over each time it
`is desired to put down or pick up a tool from the ground,
`which is customary practice at most construction Sites. A
`Single Source inductor array located on an extension cord
`may be connected at another location, with a sinusoidal
`undulating Source array at another location and a bump array
`at another, to provide additional recharging opportunities.
`The different Source arrayS could also transfer power to each
`other through their inductive interfaces. Thus, there would
`be no further need for a conventional plug and Socket
`connection to recharge the device.
`It is preferable to provide for positive engagement
`between the receiver and the Source. This may prove useful
`when the Source is positioned other than in a horizontal
`position and when the interface is Subjected to vibration or
`jostling, Since it produces a tighter magneto-inductive cou
`pling (between Source and appliance) by ensuring the best
`proximity and/or alignment of coils. This, in turn, helps
`overcome possible magnetic repulsion between the coupled
`Sets of Source and appliance inductors. This desirable result
`may be achieved by provision of a magnet, e.g., a permanent
`magnet, in the center or edge of each repeating coil unit of
`the appliance or Source coils to mate with another magnet or
`magneto attractive mass positioned in the center or edge of
`each repeating coil unit of Source or appliance coil, respec
`tively.
`The iron or other core material employed in each inductor
`coil has a Sufficient degree of permanent magnetism to
`function as engagement devices, Since these cores are ideally
`located for this purpose. In effect, the magnetic attraction is
`Sufficient to open the coil Switch and thus operate the
`charging System. However, it could be that the degree of
`permanent magnetism needed to align the coils is incom
`patible with the electro-magnetizability (permeability)
`required for the core to function efficiently in an inductor, in
`which case the alignment magnet may be set orthogonal to
`the inductor primary axis of the "X-y plane, preferably
`mutually centered, as shown in FIG. 8.
`If each coil has a degree of mobility at each of its ends
`approximately equal to half the Spacing between coils,
`intercoil spacing will allow the pairs of coils to assume
`alignment. Such mobility of the coils can be achieved by
`using braided wires in the coil connections and a housing
`larger than the diameter of the coils. This allows the coils to
`Slide in the X-y plane, wherein one Surface of the housing is
`the interface Surface of the Source array. Alternatively,
`Velcro (E) mating tongues and grooves in the Source and
`receiver or mating physical Structures may be employed as
`engagement members. In each of these embodiments, the
`fact that the housing is larger than the size of the coils makes
`it possible for the pairs of coils to achieve proper alignment.
`Alternatively, the hous