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Title:
LINEAR-RESONANT VIBRATION MODULE
Document Type and Number:
WIPO Patent Application WO/2010/135383
Kind Code:
A2
Abstract:
Various embodiments of the present invention comprise linear-resonant vibration modules that can be incorporated in a wide variety of appliances, devices, and systems to provide vibrational forces. The vibrational forces are produced by linear oscillation of a weight or member, in turn produced by rapidly alternating the polarity of one or more driving electromagnets. Feedback control is used to maintain the vibrational frequency of linear-resonant vibration module at or near the resonant frequency for the linear-resonant vibration module. Linear-resonant vibration modules can be designed to produce vibrational amplitude/frequency combinations throughout a large region of amplitude/frequency space.

Inventors:
ELENGA ROBIN F (US)
Application Number:
US2010/035334
Publication Date:
November 25, 2010
Filing Date:
May 18, 2010
Export Citation:
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Assignee:
RESONANT SYSTEMS INC (US)
ELENGA ROBIN F (US)
International Classes:
H02K33/14; H02K33/00; H02K33/04; H02K33/12
Domestic Patent References:
WO1998019383A11998-05-07
Foreign References:
US20060208600A12006-09-21
Other References:
See also references of EP 2433350A4
Attorney, Agent or Firm:
BERGSTROM, Robert W. (Seattle, Washington, US)
Download PDF:
Claims:
CLAIMS

I . Λ linear resonant- vibration module comprising: a housing including a chamber;. a magnetic weight that moves linearly within the chamber; a first end magnet oriented to repel the magnetic weight, closing a first end of llic chamber: a second end magnet oriented to repel the magnetic weight, closing a second end of the chamber; a driving electromagnet, fixed to the housing; a"hd control components that apply current that periodically alternates, in direction, to the coil Io linearly oscillate the. magnetic weight within the chamber in order to produce vibrational forces.

Description:
LINEAR-RESONANT VIBRATION MODULE

CROSS-REFERERNCE TO RELATED APPLICATION

This application claims the benefit of Provisional Patent Application No. 61/179,109, filed May 18, 2009.

TECHNICAL FIELD

The present invention is related to vibration-generating devices and, in particular, to vibration modules that can be incorporated into a wide variety of different types of electromechanical devices and systems to produce vibrations of selected amplitudes and frequencies over a wide range amplitude/frequency space.

BACKGROUND

Vibration-inducing motors and mechanisms have been used for many years in a wide variety of different consumer appliances, toys, and other devices and systems. Examples include vibration signals generated by pagers, vibration-driven appliances, such as hair-trimming appliances, electric toothbrushes, electric toy football games, and many other appliances, devices, and systems. The most common electromechanical system used for generating vibrations is an intentionally unbalanced electric motor.

Figures 1Λ-B illustrate an unbalanced electric motor typically used for generating vibrations in a wide variety of different devices. As shown in Figure I A, a small, relatively low-power electric motor 102 rotates a cylindrical shaft 104 onto which a weight 106 is asymmetrically or mounted. Figure I B shows the weight asymmetrically mounted to the shaft, looking down at the weight and shaft in the direction of the axis of the shaft, As shown in Figure I B, the weight 106 is mounted off-center on the electric-motor shaft 104. Figures 2A-B illustrate the vibrational motion produced by the unbalanced electric motor shown in Figures IA-B. As shown in Figures 2A-B, the asymmetrically-mounted weight creates an elliptical oscillation of the end of the shaft, normal to the shaft axis, when the shaft is rotated at relatively high speed by the electric motor. Figure 2A shows displacement of the weight and shaft from the stationary shaft axis as the shaft is rotated, looking down on the weight and shaft along the shaft axis, as in Figure I B. In Figure 2A, a small mark 202 is provided at the periphery of the disk-shaped end the of electric-motor shaft to illustrate rotation of the shaft. When the shaft rotates at high speed, a point 204 on the edge of the ucight traces an ellipsoid 206 and the center of the shaft 208 traces a narrower and smaller ellipsoid 210. Were the shaft balanced, the center of the shaft would remain at a position 212 in the center of the diagram during rotation, but the presence of the asymmetrically-mounted weight attached to the. shaft, as well as other geometric and weight-distribution characteristics of the electric motor, shaft, and unbalanced weight together create forces that move the end of the shaft along the, elliptical path 210 when the shaft is rotated at relatively high speed. The movement can be characterized, as shown in Figure 2B, by a major axis 220 and minor axis 222 of vibration, with the direction of the major axis of vibration equal to the direction υf the major axis of the ellipsoids, shown in Figure 2A. and the length of the major axis corresponding to the amplitude of vibration in this direction. In many applications, in which a linear oscillation is desired, designers seek to force the major-axis- amplitude/minor-axis-amplitude ratio to be as large as possible, but, because the vibration is produced by a rotational force, it is generally not possible to achieve linear oscillation. In many cases, the path traced by the shaft center may be close to circular. The frequency of vibration of the unbalanced electric motor is equal to the rotational frequency of the electric-motor shaft, and is therefore constrained by the rate at which the motor can rotate the shaft. Λt low rotational speeds, little vibration is produced.

While effective in producing vibrations, there are many problems associated with the unbalanced-clectric-motor vibration-generating units, such as that shown in Figure IA, commonly used in the various devices, systems, and applications discussed above. First, unbalancing the shaft of an electric motor not only produces useful vibrations that can be harnessed for various applications, but also produces destructive, unbalanced forces within the motor that contribute to rapid deterioration of motor parts. Enormous care and effort is undertaken to precisely balance rotating parts of motors, vehicles, and other types of machinery, and the consequences of unbalanced rotating parts are well known to anyone familiar with automobiles. machine tools, and other such devices and systems. The useful lifetimes of many devices and appliances, particularly hand-held devices and appliances, that employ unbalanced electric motors for generating vibrations may range from a few tens of hours to a few thousands of hours of use. after 'which the vibrational amplitude produced by the devices declines precipitously as the electric motor and other parts deteriorate.

A second problem with unbalanced electric motors is that they are relatively inefficient at producing vibrational motion. A far greater amount of power is consumed by an unbalanced electrical motor to produce a given vibrational force than the " theoretical minimum power required to, produce the given vibrational force. As a result, many hand-held devices that employ unbalanced electric motors for generating vibrations quickly consume batteries during use.

A third problem with unbalanced electric motors, discussed above, is that they generally produce elliptical vibrational modes. Although such modes may be useful in particular applications, many applications can better use a linear oscillation, with greater directional concentration of vibrational forces. Linear oscillation cannot generally be produced by unbalanced electric motors.

A fourth, and perhaps most fundamental, problem associated with using unbalanced electric motors to generate vibrations is that only a very limited portion of the total vibrational-force/frequency space is accessible to unbalanced electric motors. Figure 3 shows a graph of vibrational force with respect to frequency for various types. of unbalanced electric motors. The graph is shown as a continuous hypothetical curve, although, of course, actual data would be discrete. As shown in Figure 3, for relatively low-power electric motors used in hand-held appliances, only a fairly narrow range of frequencies centered about 80 Hz (302 in Figure 3) generate a significant vibrational force. Moreover, the vibrational force is relatively modest. The bulk of energy consumed by an unbalanced electric, motor is used to spin the shaft and unbalanced weight and to overcome frictional and inerlial forces within the motor. Only a relatively small portion of the consumed energy is translated into desired vibrational forces. Because of the above-discussed disadvantages with the commonly employed unbalanced-electric-motor vibration-generation units, designers, manufacturers, and. ultimately, users of a wide variety of different vibration-based devices, appliances, and systems continue to seek more efficient and capable vibration-generating units for incorporation into many consumer appliances, devices, and systems.

SUMMARY

Various embodiments of the present invention comprise lincar- resonant vibration modules that can be incorporated in a wide variety of appliances, devices, and systems to provide vibrational forces. The vibrational forces are produced by linear oscillation of a weight or member, in turn produced by rapidly alternating the polarity of one or more driving electromagnets. Feedback control is used to maintain the vibrational frequency of linear-resonant vibration module at or near the resonant frequency for the linear-resonant vibration module. Linear-resonant vibration modules can be designed to produce vibrational amplitude/frequency combinations throughout a large region of amplitude/frequency space.

BRIEF DESCRIPTION OF THE DRAWINGS Figures I A-B illustrate an unbalanced electric motor typically used for geneiating vibrations in a wide variety of different devices.

Figures 2A-B illustrate the vibrational motion produced by the unbalanced electric motor shown in Figures 1 A-B.

Figure 3 shows a graph of vibrational force with respect to frequency for various types of unbalanced electric motors.

Figures 4A-G. illustrate one particular LRVM. and operation of the particular LRVM. that represents one embodiment of the present invention.

Figures 5A-B illustrate an H-bridge switch that can be used, in various embodiments of the present invention, to change the direction of current applied to the coil that drives linear oscillation within a linear-resonance vibration module C'LRVM"). Figure 6 provides a block diagram of the LRVM. illustrated in Figures 4A-G. that represents one embodiment of the present invention.

Figures 7A-C provide control-flow diagrams that illustrate the control program, executed by the-CPU, that controls operation of an LRVM that represents one embodiment of the present invention.

Figure 8 represents the range of frequencies and vibrational forces that can achieved by different implementations of LRVM and LRVM control programs that represent embodiments of the present invention.

Figure 9 shows a plot of the amplitude/frequency space and regions in that space that can be operationally achieved by unbalanced electrical motors and by LRVMs that represent embodiments of the present invention.

Figures 10-17 show a variety of different alternative implementations of LRVMs that represent different embodiments of the present invention.

Figure 18 illustrates an enhancement of the embodiment of the present invention shown in Figure 16.

Dl-TAILED DESCRIPTION

Embodiments of th& present invention include various types of linear- resonant vibration modules ("LRVMs") that can be used within a wide variety of different types of appliances, devices, and systems, to generate vibrational forces. The LRVMs that represent embodiments of the present invention are linear in the sense that the vibrational forces are produced by a linear oscillation of a weight or component within the LRVM. rather than' as a by-product of an unbalanced rotation, as in the case of currently-employed unbalanced electric motors: The linear nature of the LRVM vibration-inducing motion allows the problems associated with unbalanced-electric-motor vibrators, discussed above, to be effectively addressed. An oscillating linear motion does not produce destructive forces that quickly degrade and wear out an unbalanced electric motor. A linearly oscillating mechanism is characterized by parameters that can be straightforwardly varied in order to produce vibrations of a desired amplitude and frequency over a very broad region of amplitude/frequency space. Combining a linearly oscillating vibration-inducing mechanism with feedback control, so that the frequency of vibration falls close to the resonant frequency of the LRVM 1 results in optimal power consumption with respect to the amplitude and frequency of vibration produced by the LRVM. Clearly, linear oscillation within a LRVM translates into highly direction vibrational forces produced by an appliance or device that incorporates the LRVM.

Figures 4Λ-G illustrate one particular LRVM, and operation of the particular LRVM, that represents one embodiment of the present invention. Figures 4A-G all use the same illustration conventions, next discussed with reference to Figure 4A. The LRVM includes a cylindrical housing 402 within which a solid, cylindrical mass 404, or weight, can move linearly along the inner, hollow, cylindrically shaped chamber 406 within the cylindrical housing or tube 402. The weight is a magnet, in the described embodiment of the present invention, with polarity indicated by the "+" sign 410 on the, right-hand end and the "-" sign 412 on the left-hand end of the weight 404. The cylindrical chamber 406 is capped by two magnetic disks 414 and 416 with polarities indicated by the "+" sign 418 and the "-" sign 420. The disk-like magnets 414 and 418 are magnetically oriented opposite from the magnetic orientation of the weight 404, so that when the weight moves to either the extreme left or extreme right sides of the cylindrical chamber, the weight is repelled * by one of the disk-like magnets, at the left or right ends of the cylindrical chamber. In other words, the disk-like magnets act much like springs, to facilitate deceleration and reversal of direction of motion of the weight and to minimize or prevent mechanical-impact forces of the weight and the end caps that close off the cylindrical chamber. Finally, a coil of conductive wire 420 girdles the cylindrical housing, or tube 402 at approximately the mid-point of the cylindrical housing. Figures 4B-G illustrate operation of the LRVM shown in Figure 4A.

When an electric current is applied to the coij, 420 in a first direction 422, a corresponding magnetic force 424 is generated in a direction parallel to the axis of the cylindrical chamber, which accelerates the weight 404 in a first direction 424. When the weight reaches a point at or close to the corresponding disk-like magnet 414, as shown in Figure 4C, a magnetic force due to the repulsion of the disk-like magnet 414 and the weight 404, 426. is generated in the opposite direction, decelerating the weight and reversing its direction. As the weight reverses direction, as shown in Figure 4D. current is applied in an opposite direction 430 to the coil 420. producing a magnetic force 432 in an opposite direction from the direction of the magnetic force shown in Figure 4B, which accelerates the weight 404 in a direction opposite to the direction in which the weight is accelerated in Figure 4B. As shown in Figure 4E, the weight then moves rightward until, as shown in Figure 4F. the -weight is decelerated, stopped, and then accelerated in " the opposite direction by repulsion of the disk-like magnet 41,6. An electrical current is then applied to the coil 420 in the same direction 434 as in Figure 4B. again accelerating the solid cylindrical mass in the same direction as in Figure 4B. Thus, by a combination of a magnetic field with rapidly reversing polarity, generated by alternating the direction of current applied to the coil, and by the repulsive forces between the weight magnet and the disk-like magnets at each end of the hollow, cylindrical chamber, the weight linearly oscillates back and forth within the cylindrical housing 402, imparting a direction force at the ends of the cy lindrical chamber with each reversal in direction.

Clearly, the amplitude of the-vibration and vibrational forces produced are related to the length of the hollow chamber in which the weight oscillates, the current applied to the coil, the mass of the weight, the acceleration of the weight produced by the coil, and the mass of the entire LRVM. All of these parameters are essentially design parameters for the LR-VM, and thus the LRVM can be designed to produce a wide variety of different amplitudes.

The. frequency of the oscillation of the solid, cylindrical mass is determined by the.frequency at which the direction of the current applied to the coil is changed. Figures 5A-B illustrate an H-bridge switch that can be used, in various embodiments of the present invention, to change the direction of current applied to the coil that drives linear oscillation within an LRVM. Figures 5A-B both use the same illustration conventions, described next with respect to Figure 5A. The H- bridge switch receives, as input, a directional signal d 502 and direct-current ("DC") power 504. The direction-control signal r/ 502 controls four switches 506-509, shown as transistors in Figure 5 A. When the input control signal d 502 is high, or "1," as shown in Figure 5A, switches 508 and 509 are closed and switches 506 and 507 arc open, and therefore current flows, as indicated by curved arrows, such as curved arrow 510. from the power-source input 504 to ground 512 in a leftward direction through the coil 514. When the input-control signal d is low. or "0," as shown in Figure 5B, the direction of the current through the coil is reversed. The H-bridge switch, shovvn in Figures 5A-B, is but one example of various different types of electrical and electromechanical switches that can be used to rapidly alternate the direction of current within the coil of an LRVM.

Figure 6 provides a block-diagram of the LRVM, illustrated in Figures 4A-G. that represents one embodiment of the present invention. The LRVM. in addition to the cylindrical housing, coil, and interna! components shovvn in Figure 4A. includes a power supply, a user interface, generally comprising electromechanical buttons or switches, the H-bridge switch, discussed above with reference to Figures 5A-B. a central processing unit ("CPU"), generally a small, low-powered microprocessor, and one or more electromechanical sensors. All of these components are packaged together as an LRVM within a vibration-based appliance, device, or system.

As shown in Figure 6. the LRVM 600 is controlled by a control program executed by the CPU microprocessor 602. The microprocessor may contain sufficient on-board memory to store the control program and other values needed during- execution of the control program, or, alternatively, may be coupled to a low- powered memory chip 604 or flash memory for storing the control program. The CPU receives inputs from the user controls 606 that together comprise a user interface. These controls may include any of various dials, pushbuttons, switches, or other electromechanical-control devices. As one example, the user controls may include a dial to select a strength of vibration, which corresponds Io the current applied to the coil, a switch to select one of various different operational modes, and a power button. The user controls generate signals input {o the CPU 608-610. A power supply 612 provides power, as needed, to user controls 614, to the CPU 616 and optional, associated memory, to the H-bridge switch 618, and, when needed, to one or more sensors 632. The voltage and current supplied by the power supply to the various components may vary, depending on the operational characteristics and requirements of the components. The H-bridge switch .620 receives a control-signal input d 622 from the CPU. The power supply 6J2 receives a control input 624 from the CPU to control the current supplied to the H-bridge switch 618 for transfer to the coil 626. The CPU receives input 630 from one or more electromechanical sensors 632 that generate a signal corresponding to the strength of vibration currently being produced by the linearly oscillating mass 634. Sensors may include one or more of accelerometers. piezoelectric devices, pressure-sensing devices., or other types of sensors that can generate signals corresponding to the strength of desired vibrational forces. Figures 7A-C provide control-flow diagrams that illustrate the control program, executed by the CPU. that controls operation of an LR VM that represents one embodiment of the present invention. Figure 7A provides a control-flow diagram for the high-level control program. The program begins execution, in step 702. upon a power-on event invoked by a user through a power button or other user control. In step 702. various local variables are set to default values, including the variables: (1) mode, which indicates the current operational mode of the device; (2) strength, a numerical value corresponding to (he current user-selected strength of operation, corresponding to the electrical current applied to the coil; (3) IvIO, a previously sensed vibrational strength: (4) Ml, a currently sensed vibrational strength: (5) freq, the current frequency at which the direction of current is alternated in the coil; (6) c/, the control output to the H-bridge switch; and (7) me, a Boolean value that indicates that the frequency is currently being increased. in step 704, the control program waits for a next event. The remaining steps represent a continuously executing loop, or event handler, in- which each event that occurs is appropriately handled by the control program. In -certain implementations of the control program, events may be initiated by interrupt-like mechanisms and stacked for execution while, in more primitive implementations, certain events that overlap in time may be ignored or dropped. In the implementation illustrated in Figures 7A-C. two timers arc used, one for controlling the change in direction of the current applied to the coil, at a currently established frequency, and the other for controlling a monitoring interval at which the control program monitors the vibrational force currently produced. Rather than using a formal limer mechanism, certain implementations may simply employ counted loops or other simple programming techniques for periodically carrying out tasks. When an event occurs, the control program begins a series of tasks, the first of which is represented by the conditional tstep 706, to determine what event has occurred and appropriately handle that event. When the frequency timer has expired, as determined in step 706. the value of the output signal d is flipped, in step 708, and output to the H-bridge switch, with the frequency timer being reset to trigger a next frequency- related event. The frequency-timer interval is determined by the current value of the variable freq. Otherwise, when the event is a monitor timer expiration event, as determined in step 710, then a routine "monitor" is called in step 712. Otherwise, when the event corresponds to a change in the user input through the user interface, as determined in step 714, the routine "control" is called in step 716. Otherwise, when the event is a power-down event, as determined in step 718, resulting from deactivation of a power button by the user, then the control program appropriately powers down the device, in step 720, and the control program terminates in step 722. Any other of various types of events that may occur are handled by a default event handler 724. These events may include various error conditions that arise during operation of the device.

Figure 7B provides a control-flow diagram for the routine "monitor." called in step 712 of Figure 7A. In step 730, the routine "monitor" converts the sensor input to an integer representing the current vibrational force produced by the LRViVf and stores the integer value in the, variable Ml. Next, in step 732, the routine "monitor" determines whether or not the LRVM is currently operating in the default mode. In the default mode, the LRVM uses continuous feedback control to optimize the vibrational force produced by the LRVM by continuously seeking to operate the LRVM at a frequency as close as possible to the resonant frequency for the LRVM. Other, more complex operational modes may be handled by various more complex routines, represented by step 734 in Figure 7B. More complex vibrational modes may systematically and/or periodically alter the frequency or produce various complex. multi-component vibrational modes useful in certain applications, appliances, devices, and systems. These more complex modes are application dependent, and are not further described in the control-flow diagrams. In the case that the operational mode is the default mode, in which the control program seeks to optimize the vibrational force generated by the device, in step 736. the routine "monitor" determines whether the local variable inc is set to TRUE. If so. then the control program is currently increasing the frequency at which the device operates in order to obtain the resonance frequency. When Ml is greater than IvIO. as determined in step 738, then the vibrational force has been recently increased by increasing the frequency, and so the routine "monitor" increases the frequency again, in step 740, and correspondingly resets the frequency timer. Otherwise, when IvIl is less than IvIO, as determined in step 742. then the control program has increased the frequency past the resonance frequency, and therefore, in step 744, the control program decreases the frequency, sets the variable inc to FALSE, and correspondingly resets the frequency timer. In similar fashion, when the variable inc is initially FALSE, as determined in step 736, and when IvIl is greater than IvIO. as determined in step 746, the routine "monitor" decreases the value stored in the variable Jreq. in step 748 and resets the frequency timer. Otherwise, when IvII is less than MO, as determined in step 750, then the routine "monitor" increases the value stored in the variable freq. sets the variable inc to TRUE, and resets the frequency timer in step 752. Finally, the value in Ml is transferred to MO and the monitor timer is reset 3 in step 754. Figure 7C provides a control-flow diagram for the routine "control." called in step 716 in Figure 7A. This routine is invoked when a change in the user controls has occurred. In step 760. the variables mode and strength are set to the currently selected mode and vibrational strength, represented by the current states of control features in the user interface. Next, in step 762, the routine "control" computes an output value/; corresponding to the currently selected strength, stored in the variable strength, and outputs the value p to the power supply so that the power supply outputs an appropriate current to the coil. Finally, in step 764, the routine "control" computes a new monitor timer interval and resets the monitor timer accordingly. The control program described with reference to Figures 7A-C is one example of many different implementations of the control program that can be carried out, depending on requirements of the LRVM, the parameters and characteristics inherent in a particular LRVM. the types of control inputs received from a particular user interface, the nature of the power supply, and the types of operational modes that are implemented for the LRVM. Figure 8 represents the range of frequencies and vibrational forces that can achieved by .different implementations of LRVM and LRVM control programs that represent embodiments of the present invention. Figure 8 has the same axes as the graph shown in Figure 3. However, unlike Figure 3. Figure 8 includes many different curves, such as curve 802, each representing the vibrational forces and frequencies that can be obtained from a particular LRVM implementation. Again, the LRVMs that represent embodiments of the present invention generally have a resonant frequency that is characteristic of the geometry and weights of various components of the LRVM. and each LRVM is naturally operated at a frequency close to this resonant frequency in order to achieve maximum vibrational force. Thus, rather than being restricted, over all possible implementations, to a relatively narrow range of frequencies and vibrational forces, as in the case of unbalanced electrical motors. LRVMs that represent embodiments of the present invention can be designed and implemented to produce desired vibrational forces over a wide range of vibrational frequencies, and desired vibrational frequencies over a wide range of desired vibrational forces. The contrast is perhaps best seen in Figure 9. Figure 9 shows a plot of the amplitude/frequency space and regions in that space that can be operationally achieved by unbalanced electrical motors and by LRVMs that represent embodiments of the present invention. Unbalanced electric motors can be implemented to produce amplitude/frequency combinations roughly within the cross- hatched square region 902 within amplitude/frequency space. By contrast, LRVMs can be designed and implemented to produce amplitude/frequency combinations underlying curve 904. Thus. LRVMs can achieve much higher operational frequencies and much lower operational frequencies than can be practically obtained by unbalanced electric motors, and can produce much higher amplitudes and vibrational forces than can be achieved by relatively low-powered unbalanced electrical motors used in hand-held appliances and other commonly encountered devices and systems. Furthermore, when larger vibrational forces are needed, balanced electrical motors arc generally impractical or infeasible, due to the destructive forces produced within the electrical motors.

Figures 10- 17 show a variety of different alternative implementations υf LRVMs that represent different embodiments of the present invention. Figure 10 provides a schematic illustration of an LRVM similar to that discussed above with reference to Figure 4A. Note that, in place of the end magnets- 1002 and 1004. mechanical springs may alternatively be used. These may be traditional helical springs made from metal or springs made from a compressible and durable material or mechanical device that seeks to restore its initial shape when depressed or compressed. Note that the weight and chamber may be cylindrical, in cross section, as discussed above with reference to Figure 4A. or may have other shapes, including rectangular or hexagonal cross-sections.

Figure 1 1 shows a similar implementation in which the control unit and power supply are incorporated into the moving mass 1 102. In this implementation, the relative masses of the moving mass 1 102 and remaining components of the LRVM is maximized, thus maximizing the vibrational forces produced at a given level of power consumption.

Figure 12 shows yet an alternative LRVM embodiment of the present invention. In this alternative implementation, additional coils 1202 and 1204 arc incorporated in the moving mass, and a centering magnet or coil 1206 is positioned in a fixed location on the housing so that, when the direction of the current applied to the coils 1202 and 1204 is alternated, an oscillating rotational force is generated to cause the movable weight to oscillate both in a plane perpendicular to the axis of the chamber as well as linearly oscillating the direction of the chamber.

Figure 13 illustrates an embodiment in which multiple electromagnetic coils are employed. In Figure 13. two coils 1302 and 1304 are placed in two different positions on the housing. The first coil 1302 may be used to drive linear oscillation of the moving mass 1306, while the second coil may be activated in order to shorten the length of the chamber within which the moving mass linearly oscillates, essentially serving as a second repelling magnet. In this implementation of the LRVM 1 the LRVM 3 the moving mass may linearly oscillate with at least two different amplitudes, depending on whether or not the second coil 1304 is activated to repel the moving mass. Additionally more complex patterns of current reversal in the two coils can be employed to produce complex multi-component vibrational modes of the moving mass.

When the housing is fully enclosed, air within the chamber serves to dampen oscillation of the moving mass. This dampening may be minimized by providing channels, on the sides of the moving mass, to allow air to pass from one side of the moving mass to the other, by channels through the moving mass, or by providing openings in the housing to allow air to be forced from the housing and drawn into the housing. Additionally, different " fluids or liquids may be employed within the chamber to change the dampcning-effect produced by displacement of the fluids and gasscs as the moving,mass linearly oscillates.

Figure 14 illustrates an alternative LRVM embodiment of the present invention in which a plunger linearly oscillates to produce a vibration. The plunger

1402 is oriented orthogonally to a main housing 1404 of the LRVM that includes the power supply, microcontroller, and other control components. The plunger is girdled by, or includes, a driving magnet 1406 that is attracted to, and seeks to be positioned in alignment with, a centering magnet 1408 mounted within the housing. Applying current to one of two driving coils 1412 and 1414 forces the .driving magnet away from the equilibrium position shown in Figure 14. By rapidly switching the direction of current applied to the driving coils, the microcontroller can control the plunger to linearly oscillate in an up-and-down fashion, as indicated by arrow 1420.

Figure 15 shows yet another LRVM embodiment of the present invention. In this embodiment of the present invention, a spring-like member 1502 is clamped at one end 1504 to the housing. Driving magnets 1506 and 1508 are fixed to the spring-like member ,1502, and when current is rapidly reversed in a coil 1510. the spring-like member 1502 is induced to vibrate at a relatively high-frequency.

Figure 16 shows an alternative embodiment of the present invention similar to the embodiment shown in Figure 15. In this embodiment, the spring member 1602 is extended to provide an external massage arm 1604 that extends out from the housing to provide a linearly oscillating massage-foot member 1606 for massaging human skin or some other substrate, depending on the application.

Figure 17 shows a mechanical vibration adjustment feature that can be added to either of the embodiments shown in Figures 15 and 16. An adjustment screw 1702 can be manipulated to alter the position of a movable spring clamp 1704 that acts as a movable clamping point for the spring-like member 1706. Moving the movable, spring clamp 1704 leftward, in Figure 17, shortens the length of the springlike member and thus tends to increase the vibrational frequency at a particular power-consumption level. Conversely, moving the movable-spring' clamp rightward. in Figure 17, lengthens the spring-like member and decreases the vibrational frequency.

Figure 18 illustrates an enhancement of the embodiment of the present: invention shown in Figure 16. In this embodiment, the massage foot is enhanced to include elastomer bristles 1802-1805 to transfer the linear oscillation of the massage foot to human skin or another substrate.

Although the present invention has been described in terms of particular embodiments, it is not intended that the invention be limited to these embodiments. Modifications will be apparent to , ' those skilled , in the art. For example, as discussed above, LRVMs can be designed to produce desired vibrational amplitudes and frequencies over a wide region of amplitude/frequency space by varying various different design parameters and characteristics, including the amplitude of a moving mass that linearly oscillates within the LKVM, altering the dimensions of the LRVM and internal components of the LRVM, altering the weight of the moving mass and other components of the LRVM. changing the ratio of the moving mass to the ratio of the remaining components of the LRVM, increasing or decreasing the number of turns in the coil or coils used to drive linear oscillation, increasing or decreasing the current supply to the coils, altering the dampening produced by displacement of fluid or gas by the moving mass within the LRVM as well as by various additional frictional forces, altering the strength of the end-cap magnets or mechanical springs used to facilitate reversal of direction of the moving mass, and by changing any of various additional parameters and characteristics. Any of various different microprocessors and other microcontrollers can be used in alternative embodiments of the LRVM. as- well as different power supplies, current- switching devices, and other components. The control program executed by the LRVM can be implemented in many different ways by varying any of many different design parameters, including programming language, control structures, dam structures, modular organization, and other such design parameters. The components of the LRVM. including the housing, moving mass, fixed magnets, and electromagnets, can be fashioned from many different types of materials, from polymers and plastics to metals and alloys in various composite materials. LRVMs may contain one, two. or more electromagnets and/or permanent magnets in order to produce linear oscillation of a moving mass or spring-like mass, and various different control programs can be implemented to produce many different types of single- component and multi-component vibrational modes, some of which may regulaily or erratically change, over time, to produce a wide variety of different types of vibrational characteristics. An additional housing made from a material with a relatively large magnetic permeability can be added to various embodiments of the present invention to concentrate and increase the linearmagnetic forces produced by the various coils.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, if will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. The foregoing descriptions of specific embodiments of the present invention are presented for purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the piecise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments are shown and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents: