Abstract:
A sexual stimulation device includes an elongated dildo housing sized to be received within an orifice of a human body, the housing defining an internal cavity extending along a longitudinal axis of the housing, a mass laterally constrained within the cavity and movable linearly along the cavity, and an electrically driven actuator disposed within the housing and operably coupled to the mass. The actuator is operable to accelerate the mass along the cavity and to thereby induce a longitudinal reactive acceleration of the housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of co-pending U.S. application Ser. No. 12/539,529 (Sexual Stimulation Devices and Methods) filed Aug. 11, 2009, which claims the benefit of U.S. provisional application Ser. No. 61/087,821 (Sexual Stimulation Devices and Methods) filed Aug. 11, 2008, the entire disclosures of both of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to devices and methods to sexually stimulate the human body. 
     BACKGROUND 
     Vendors today manufacture vibrators with a small mass (typically under 5 grams), with high frequency (typically 200 to 1000 RPM) and with the mass located off-center on a rotary motor. These devices are characterized by providing non-motile vibration. While popular, one of the known limitations of these products is that high frequency vibration can desensitize the sexual response, thereby making non-vibratory sexual relations more difficult. There are also phallus-shaped devices that provide very low frequency, high amplitude thrusting motions designed to mimic the sexual act without necessitating motion of the base. Such devices can be “stand-alone” (i.e., with one end immovably constrained) or hand held. Both seek to mimic the thrusting motions of intercourse. 
     SUMMARY 
     According to one aspect of the invention, a sexual stimulation device includes an elongated dildo housing sized to be received within an orifice of a human body, the housing defining an internal cavity extending along a longitudinal axis of the housing, a mass laterally constrained within the cavity and movable linearly along the cavity, and an electrically driven actuator disposed within the housing and operably coupled to the mass. The actuator is operable to accelerate the mass along the cavity and to thereby induce a longitudinal reactive acceleration of the housing. 
     In some examples, wherein the housing comprises a flexible sheath overlaying a structural member. 
     In some embodiments, the actuator comprises a linear motor or an electromechanical solenoid. The mass may include an armature of the solenoid. In some cases, a majority of the mass is disposed outside of a coil of the solenoid. In some cases, the mass includes a weight removably attached to the solenoid armature. For many applications, the solenoid has an armature slidably disposed within a solenoid bore having a diameter of between about 1.5 and 10 mm. 
     Some embodiments also include a lateral mass displaceable with respect to the housing only in a direction substantially perpendicular to the longitudinal axis. 
     In some configurations the actuator includes a rotary motor coupled to a transmission that converts rotary motor armature motion to linear mass motion. For example, the transmission may include a screw shaft disposed within a nut element constrained against rotation with respect to the housing. In another example, the transmission includes a first gear secured to an armature of the motor, and a second gear operably coupled to the first gear and mounted to rotate about an axis perpendicular to the motor armature. A connecting link, such as a flex spring or a rigid connecting rod, may rotatably connected to an offset pivot point of the second gear and attaching the second gear to the mass. 
     Preferably, the actuator is operable to move the mass a longitudinal distance of at least 10 mm, in some cases at least 20 mm, with respect to the housing. 
     Some examples include a signal receiver connected to the actuator and responsive to a control signal from a remote operator. 
     Some examples include a controller configured to control motion of the mass according to a preset motion profile. In some cases, the motion profile includes a first acceleration rate in a first direction along the longitudinal axis, and a second acceleration rate in a second direction along the longitudinal axis, the second acceleration rate differing from the first acceleration rate. 
     Some embodiments also include an internal power source, such as one or more batteries, disposed within the housing and connected to the actuator through a switch and/or a controller. 
     Some embodiments also include a handle disposed at one end of the dildo housing, with an isolator connecting the dildo housing and handle. The dildo housing may be slidably coupled to the handle, for example. 
     Preferably, the actuator is operable to induce an overall longitudinal motion of the device, the induced overall motion having an amplitude of at least 4 mm. 
     The actuator is preferably operable to induce an overall longitudinal motion of the device with an amplitude at least 10 times greater than an amplitude of any lateral motion of the device induced by actuator operation. 
     In some examples the mass is of a non-ferromagnetic material, such as lead or tungsten. 
     Another aspect of the invention features a method of creating sexual stimulation. The method includes bringing the above-described device into contact with a sexual organ, and holding the device in contact with the sexual organ while the actuator is operated to move the mass along the cavity. 
     Another aspect of the invention features a massage device with a cylindrical housing, an electromechanical arrangement disposed in the housing for generating mechanical vibrations, an electronic controller for controlling the electromechanical arrangement, and a power source electrically coupled to the electromechanical arrangement and the electronic controller. The electromechanical arrangement includes at least one coil element and at least one ferromagnetic core arranged parallel or coaxial with the coil element and movably guidable parallel to a cylinder axis of the housing. 
     Embodiments of this invention may be advantageously configured to provide a stimulation that may be different from the thrusting motion of intercourse and yet not as desensitizing to the sexual organs as some known devices and methods. This different stimulation may be oscillatory, but with a frequency lower than provided by typical rotary vibrators with an off-center mass. Some examples may be capable of providing stimuli that are varied, controllable, and subtle. The variable sensation may be independent of any thrusting motion imposed on the device by the hand of the user, and the variable sensation may be dependent on the thrusting motion in a variety of predictable and semi-predictable and non-predictable ways. The sensation may be dynamically variable, or under dynamic control, whether the user is co-located, or distant. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view of a dildo with a linear vibration, large masses and linear actuators. 
         FIG. 2  is a sectional view of a dildo with linear vibration, interchangeable masses, and linear actuators. 
         FIG. 3   a  shows an exposed isometric view of the mechanics of a dildo with linear vibration, large mass, and a screw actuator. 
         FIG. 3   b  shows an exposed end view of the dildo of  FIG. 3   a    
         FIG. 4   a  shows an exposed isometric view of the mechanics a dildo with motile vibration, large mass, and a rotary actuator. 
         FIG. 4   b  shows an exposed end view of the dildo of  FIG. 4   a.    
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a sexual pleasure device  3  with a linear displacement actuator  80  oriented radially, and accelerating a mass  276   b  and a second linear displacement actuator  80  oriented axially, and accelerating a mass  276   a  within the device. The weight of each of the accelerated masses  276   a  and  276   b  (calculated separately along each axis) is selected according the desired performance dictated by MV=mv where: 
     m—mass of the accelerated mass ( 276   a  or  276   b ) 
     v=the velocity imposed upon the accelerated mass by its displacement actuator 
     M=the mass of the device, less the accelerated mass 
     V=the velocity of the device as it physically displaces along the axis of motion. 
     Compared to some known sexual stimulation products containing accelerated masses, in this device the accelerated mass is substantially increased, the frequency is substantially decreased, the motion of the mass is linear, and the mass drive mechanism is internal to the device. The objective is to provide a sensation that is not vibratory, but rather a physical displacement of the device that is superimposed on the self-directed hand motion. Unlike the prior art, this embodiment is capable of a single oscillation cycle providing a significant sensation to a user, because a measurable degree of motion and hence friction is felt, as opposed to merely non-motile vibration. This additional motion may be along the major axis, as provided by mass  276   a  and its associated linear displacement actuator  80  (providing a displacement force along axis  277   a ), or may be along the a radial axis, as provided by mass  276   b  and its associated linear displacement actuator  80 , providing a displacement force along axis  277   b . Linear displacement actuators  80  include two types: the first is electromechanical solenoid  86 , typically a metal rod or metal core  97  within a coil of wire (often with a return spring) typically used for transient force application with a low degree of control. In one example, the diameter of the metal core  97  is in the range from 1.5 mm to 10 mm. Field strength in a solenoid is independent of diameter. Therefore, a benefit of small diameter metal cores  97  is to reduce the amount of conductor (typically copper) needed to manufacture the associated solenoid. The second type of linear actuator  80  is a linear motor  87 , typically a magnet (or magnets) placed within a magnetic field and typically used for higher degrees of control. Creating motion of a magnet by flowing electrical current through a wire and using induction to move a rod within a solenoid is disclosed in high school physics texts. Masses  276   a  and  276   b  may be made from any dense material such as steel, lead or tungsten. In one embodiment, each mass  276   a  (or  276   b ) and its associated linear displacement actuator  80  are separate elements. In the preferred embodiment the cross section of mass  276   a  and  276   b  is round, but other cross-sections are envisioned. 
     The housing of the device may include an elastomeric sheath over an internal housing  137 . The user&#39;s hand may be shielded from the motions of the device through an isolation mechanism  44  located between handle  136  and internal housing  137  or shaft  155 . Isolation mechanism  44  may include a spring element  138  or a sliding mechanism, (such as a protruding wall in a groove or a flexure) that allows low friction linear motion between the shaft  155  and the handle  136 . 
     In one embodiment the displacement of mass  276   a  or mass  276   b  is at least 10 mm. In another embodiment, displacement of mass  276   a  or  276   b  is at least 20 mm. The amplitude and acceleration curves may be varied, as well as the frequency, thereby enabling a wide range of sensations to the user. For example, one embodiment provides multiple sequential stimuli in a single direction. A specific example of this embodiment is overall travel distance (X) of a linear displacement actuator  80  of 27 mm in which the device provides three sequential and discrete movements (i.e. “thumps”) of approximately 9 mm each, all in a first direction without recoiling. In one embodiment the controller  92  initiates a plurality of such sequential unidirectional discrete motions in a relatively short time, thereby providing a distinctly different sensation than simple oscillation. In one embodiment the device traverses the two longitudinal directions (i.e., in and out or plus and minus) at distinctly different rates, moving in a first direction at a high rate of speed/acceleration, thereby noticeably displacing the device (and providing the associated sensation of displacement) and subsequently returning in the opposite direction at a significantly slower rate such that the recoil and the associated motion of the device  3  is substantially smaller, if detected at all. This pattern may be repeated, thereby providing the sensation that the device is only thrusting in a single direction. By modifying the acceleration curves, displacements and sequences in this manner, a wide range of novel sensations may be provided. In one example controller  92  includes input from a wireless transceiver such as Bluetooth or Wi-Fi disposed within dildo  3 , thereby enabling communication to the Internet and cellular communications. 
     Displacement of the device in an operational mode may be measured in the following manner: The device is first fixed, in a horizontal position, to a support with a smooth bottom surface. The support, including any material used to fix the device to the support, must weigh less than 1/100 of the weight of the device. The supported device is then placed on an air table, such that a flow of air from the table maintains the support slightly elevated and free of lateral motion constraint. The device is then turned on and the external motion measured optically with respect to the air table. If lateral (non-longitudinal) motion is to be measured, the device should be mounted such that the direction of motion of the internal lateral mass is parallel to the table surface. 
     Preferably, the motion of the longitudinally accelerated internal mass will induce an overall motion of the device with an amplitude of at least 4 mm. It is also preferred, for many applications, that the longitudinal motion be at least 10 times greater in amplitude than any lateral (non-longitudinal) motion of the device. 
       FIG. 2  shows an embodiment in which masses  276   a  and  276   b  are interchangeable with masses  276   c  and  276   d , respectively. Interchangeable masses allow the physics of the device to be altered without needing to redesign other features of the product. Interchangeability is provided by locking mechanism  278 , shown here as a tapped hole in masses  276   a  and  276   b  and a threading on the end of metal rod  97 . Locking mechanism  278  may also be provided by a press fit between the two components.  FIG. 2  also shows isolation mechanism  44  embodied with a low friction bearing surface  139  such as Teflon allowing internal housing  137  (or shaft  155 ) to slidingly engage with handle  136 . 
       FIG. 3   a  shows a dildo  3  with linear vibration in which linear actuator  80  includes a high-helix screw  152  rotated by rotary electric motor  150 . Mass  276   a  is coupled to screw  152  through a low friction nut  154  which is itself permanently affixed to mass  276 . Mass  276  is restrained from rotation with respect to the body of motor  150 . In this embodiment, mass  276  is constrained from rotation about screw  152  by alignment rod  156 , which extends through hole  158 , itself disposed as far as possible from major axis  151 . Alignment rod  156  is rigidly secured to internal housing  137 . Internal housing  137  extends to cover and protect screw  152  and the motion of mass  276   a , but has been cut back in this figure to expose the inner structures. Likewise, the controller and battery have been omitted for clarity. 
     In an alternate example, mass  276   a  is constrained from rotation by a channel or ridge slidingly engaged with a corresponding ridge or channel in internal housing  137 . Any structure that prevents mass  276  from rotating while permitting displacement along major axis  151  without imposing high friction will suffice. Because the motion is oscillatory, it is important for nut  154  to closely engage with the threads of screw  152 . Techniques (such as opposed bearing surfaces including a spring force) or simply manufacturing with a high tolerance and low-wear/low-friction materials such as Teflon are known in the art. Similar connections are used in many consumer products to provide high accuracy, such as in printers and copiers. In this product the accuracy required is far lower, and the accelerated mass  276   a  is in the place of a print head or scanner element. The lower accuracy allows tolerances and related cost to be lower. 
       FIG. 3   b  illustrates how alignment rod  156  is connected to internal housing  137  by flange  166 , and that the external contour of sheath  11  may be related to the shape of the internal housing  137 . The preferred shape of the cavity  164  that contains mass  276   a  or  276   b  is round, but other shapes are within the scope of the invention. Likewise, mass  276   a  may be constrained to travel in a slight arc (i.e., similar to a real phallus) and still be considered to be “linear” as that term is used here. 
       FIG. 4   a  shows an example of dildo  3  with linear vibration in which a drive point  181  translates in a circle disposed in a plane proximate to the major diameter of the housing. In this example drive point  181  is disposed near the edge and on the back of large diameter gear  183  which is mounted for rotation with respect to the housing and driven by a small gear  184  fixed to the output shaft of rotary electric motor  150 . A variety of means can be used to oscillate mass  276   a  or  276   b  through drive point  181 . In this figure, a pin is co-molded with large diameter gear  183  at drive point  181  and a flex spring  182  is rigidly attached to mass  276   a  (or a molded carrier housing containing mass  276   a ) at one end and the other end of flex spring  182  is molded with a hole to accommodate the offset pin on gear  183 . The details of the bearings and assembly features such as screws and washers are well-known in the art and not shown. Other variations are possible. For example, flex spring  182  may be replaced with a rigid linkage that allows rotation at both ends, or with a tension member such as a string and to attach a spring to mass  276   a  or  276   b  in opposition to the tension member. Other mechanisms may use cams, barrel cams, eccentric wheels, and other linkages to couple the rotary output from electric motor  150  to mass  276   a  or  276   b  to translate rotary motion in a first plane to oscillatory motion in a perpendicular plane. Common to all previous examples, mass  276   a  or  276   b  oscillates as described in  FIG. 1 . 
       FIG. 4   b  illustrates how drive point  181  and large diameter gear  183  are disposed proximate to the middle of housing. In most cross-sections, the middle will also correspond with the point that is largest and most suitable for large diameter gear  183 . 
     While a number of examples have been described for illustration purposes, the foregoing description is not intended to limit the scope of the invention, which is defined by the scope of the appended claims. There are and will be other examples and modifications within the scope of the following claims.