Abstract:
Vibratory shavers are provided having a battery powered DC motor, which when energized rotates a weight eccentrically mounted to a motor shaft. The rotating weight imparts vibratory motion in the shaver housing and thereby a razor cartridge attached to the head of the shaver. The housing is specially designed so that the shaver head will move more front to back than side to side. This can be achieved (a) with the shaver housing having a wider aspect than a front to back aspect; (b) by thickening the side walls of the neck of the shaver relative to the front and back walls of the neck; and (c) by appropriately positioning and designing braces of varied thicknesses. The housing of the shaver may be permanently sealed and provided with a battery that may be recharged via induction. Alternatively, a cap can be provided to provide access to a replaceable battery.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not applicable.  
         STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    This invention relates to shaving implements and in particular to electric shavers.  
           [0004]    There are numerous types of electric and manual implements on the market today for removing or trimming hair present on various skin areas, especially hair on faces of men and on legs of women. Conventional manual razors have a handle with one or more straight razor blades at an upper end. Often these razors are designed to be entirely disposed of after a period of use, or the blade section of the razor is intended for disposal and replacement (with the handle being used more permanently). Such manually moved razors are suitable to be used when the skin is wet, and often when the skin is treated with a shaving cream, soap or lotion. However, the effectiveness of such shavers is limited by the ability of a human hand to manipulate the shaver head.  
           [0005]    Well-known conventional electric shavers have rotating or reciprocating blades disposed beneath a perforated screen through which the individual hairs must pass to be cut during shaving. The need for the protective screen can lead to a less consistent and “close” shave, unless various complex and costly techniques are employed to correct this problem. In any case, such electric razors are ordinarily unsuitable for use with conventional shaving creams, and many are not designed for use in a wet environment such as a shower. This latter restriction is of particular concern as many women prefer to shave their legs during their shower.  
           [0006]    There also exist some types of hybrid shavers which combine some benefits of manual razors and some of electric shavers. Specifically, these hybrid shavers can be used with shaving cream in a wet environment, while also using electric power to more rapidly move the shaving blade.  
           [0007]    Examples of such shavers include U.S. Pat. Nos. 4,744,144, 4,819,330, 4,914,816, 5,046,249 and 5,299,354. The disclosures in these patents, as well as all that in other patents cited herein, are hereby incorporated by reference as through fully set forth herein.  
           [0008]    Some of these disclose a shaver having a handle or body containing an electric oscillator or vibration inducing component and to which is attached a straight bladed razor cartridge. Others disclose vibrating shavers having switch-operated and battery-powered DC motors.  
           [0009]    In some hybrid shavers, e.g. U.S. Pat. No. 5,007,169, the shaver directly couples a stem of a shaver head to the motor shaft. Others, e.g. U.S. Pat. Nos. 3,611,568; 5,046,249 and 6,105,252, impart oscillatory motion to the razor head without direct coupling to the motive means. This can be done, for example as disclosed in U.S. Pat. Nos. 5,299,354 and 6,105,252, by eccentrically mounting a weight to the rotatable motor shaft.  
           [0010]    Rotation of the shaft causes off-center rotation of the weight which in turn imparts oscillatory motion to the razor blade(s). This motion can be passed through a unitary neck extending between the main body of the housing and the razor head, as disclosed in U.S. Pat. Nos. 3,636,627; 5,299,354 and 6,481,104. As disclosed in U.S. Pat. No. 6,421,918, the motion can even be in the ultrasonic range.  
           [0011]    These hybrid shavers typically employ an oscillating pattern for their shaving heads. Some, like those in U.S. Pat. No. 3,636,627, use an essentially circular pattern, while others essentially sweep side to side. Significant side to side motion tends to increase the risk of cuts, particularly when the tolerances of manufacture are not precise.  
           [0012]    U.S. Pat. No. 6,481,104 discloses a primarily front to back (towards and away from the skin) motion by locating the vibration axis of the weight parallel to the razor blades. However, the means of achieving this motion is costly. Further, the vibration rates of the &#39;104 patent impart an uncomfortable feel to the user&#39;s hand.  
           [0013]    The art therefore still desires improved assemblies for shaving human skin, where the shaving is effective, and can be achieved in a wet environment using conventional shaving creams and gels.  
         SUMMARY OF THE INVENTION  
         [0014]    The invention provides a vibratory shaver. There is an outer housing having an elongated body defining front, back and opposite side walls, a neck extending essentially axially from the body, and a head attached to the neck at a location remote from the body. The body and neck (and preferably the body, neck, and head) are formed, at least in part, from a continuous surface to resist side to side motion more than front to back motion. Alternatively expressed, the body and neck are formed as an essentially continuous, non-jointed structure resisting side to side motion to a greater degree than front to back motion, where “non-jointed” refers not to seams or other features where parts are substantially rigidly joined together, even if the parts still can bend or flex, but, instead, to joints intended to allow parts to pivot or otherwise move relative to each other.  
           [0015]    The neck (and preferably the body and neck in combination) is so formed as to resist side to side (lateral) motion to a greater degree than it resists front to back motion. As will be discussed further below, the neck can be solid (at least partially) or hollow and formed in any of several ways to achieve the preferred motion. For example, the neck can be formed with a maximum lateral dimension which is greater than its maximum front to back dimension, and preferably with its lateral dimension being greater than its front to back dimension over its entire length, causing it to be preferentially laterally stiff, compared to its front to back stiffness. Alternatively or in combination with that dimensional feature, the neck can be forwardly arched or curved, somewhat like the curve of a cupped hand. Preferably, the neck curves forwardly from the back-most surface of the body or even curves first backwardly from the body and then forwardly. This shape encourages preferentially lateral stiffness. Also alternatively, if the neck is hollow, the relative thickness of the side versus the front and back walls can be adjusted to affect relative flexibility, preferably with the side walls being thick compared to the front and back walls. If the neck is hollow, internal bracing also can be adjusted to resist lateral flexing while offering lesser resistance to front to back flexing.  
           [0016]    A battery is positioned in the body. A motor capable of being energized by the battery is also positioned in the body. Further, a weight is positioned in the housing and mounted to the motor so as to be rotated thereby to vibrate the housing. With the neck (or the combined body and neck) formed as disclosed above, rotation of the weight can cause the head of the shaver to oscillate with a greater front to back amplitude than lateral amplitude. It has been determined that plastic materials provide desirable vibratory characteristics, while also being resistant to water damage. Of course, other materials may also prove suitable.  
           [0017]    In one form there is a removable lower cap suitable for facilitating access to the battery. This is a form most suited for situations where the battery is disposable and replaceable after being used. This might be most appropriate for a men&#39;s shaver designed for use at a bathroom lavatory.  
           [0018]    In another form the shaver can be made rechargeable and have a permanently sealed housing. In such a case there can be a recharging cradle having a receiving cavity suitable for receiving a lower end of the housing. The cradle can be capable of recharging the battery via induction.  
           [0019]    In any case, it is intended that the shaver be used with a razor cartridge having a blade and the head include an attachment feature for removably connecting the razor cartridge to the head. For example, the attachment feature can be a side to side rail and the razor cartridge can be formed with a slot for receiving the rail. The parts can interlock in known ways on a temporary basis.  
           [0020]    In other preferred aspects there can be a switch for controlling operation of the motor, the switch being controllable from outside the housing, and the motor can have a shaft extending axially with respect to the handle, with the weight being mounted to the motor shaft eccentrically.  
           [0021]    To minimize hand discomfort, while retaining the benefits of the vibration, we have found an optimal oscillation range of 100 to 200 cycles per second, preferably an oscillation of less than 150 cycles per second, even more preferably an oscillation rate of between 120 and 140 cycles per second. With respect to oscillation amplitude, we prefer the lateral movement of the head to be less than 0.02 cm.  
           [0022]    As already discussed, the desired vibratory pattern can be achieved in various ways. For example, one form of the invention is a vibratory shaver having a solid (at least in part) but somewhat neck flexing more from front to back than side to side. In another version, the neck is hollow and defines a front neck wall, a back neck wall, and lateral neck walls connecting the front and back neck walls. The front neck wall (and preferably also the back neck wall) has at least a part of it which has a lesser thickness than at least a part of a lateral neck wall (and preferably of both lateral neck walls). In another form the vibratory pattern is achieved because bracing positioned in the housing favors front to back over lateral flexing. This can be achieved, for example, by providing a longitudinal rib attached to or unitarily formed with one or both lateral neck walls, either projecting inwardly or outwardly, the rib extending longitudinally for a part and preferably for the majority of the length of the neck. Forming the neck and/or neck and body so as to be laterally wider than it is deeper from front to back has already been discussed, as has forming the neck with a forward curve. In any event, the essence of the invention is that a stiffening means is provided to cause the head of the shaver to move preferentially in the desired, forward and backward pattern, without the need for pivoting or other jointed connections between or within the body, neck, or head.  
           [0023]    Because the shaver is designed for use with, and may include, a disposable razor cartridge, once a blade becomes dull it can easily be replaced. Further, the blades may be of conventional design, thus providing the shaver with all the benefits of a conventional hand operated shaver. Further, because the housing can be made watertight, the shaver can be designed for use in a shower or other wet environment. Nevertheless, the desired benefits of electrical movement of the shaver head are made available without unacceptable risk of side to side cuts.  
           [0024]    It should be appreciated that the precise configuration of the attachment feature and the razor cartridges is not critical to the performance of the invention. Thus, the razor cartridge could clip or snap onto the shaver in any suitable fixed or pivoting connection.  
           [0025]    The present invention thus provides a relatively low-cost electric shaver capable of using conventional disposable razor cartridges for wet or dry shaving. A low cost and reliable oscillator vibrates the housing to impart a short, rapid oscillatory motion to the razor cartridge. The dimensional and/or other physical attributes of the housing tend to limit the side to side movement of the razor cartridge such that the net motion is greater from front to back without the need for moving pivots or joints at any point along the length of the housing. Such motion improves the hair cutting efficiency per stroke of the shaver, thereby providing a closer shave in less time.  
           [0026]    These and other advantages of the invention will be apparent from the detailed description and drawings. It should be understood that the following are merely preferred embodiments of the invention. The claims should be looked to in order to understand the full scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    [0027]FIG. 1 is front plan view of a first, rechargeable embodiment of a vibratory shaver of the present invention, shown resting in a recharging cradle;  
         [0028]    [0028]FIG. 2 is a partial front view of the shaver&#39;s neck and head, and a replaceable razor cartridge separated there from;  
         [0029]    [0029]FIG. 3 is an exploded view of the shaver, shown without a razor cartridge;  
         [0030]    [0030]FIG. 4 is a cross-sectional view as it would appear if taken through the body of the shaver along line  4 - 4  of FIG. 3 had the device not been exploded for illustrative purposes;  
         [0031]    [0031]FIG. 5 is a cross-sectional view as it would appear if taken through the neck of the shaver along line  5 - 5  of FIG. 3 had the device not been exploded for illustrative purposes;  
         [0032]    [0032]FIG. 6 is a cross-sectional view as it would appear if taken through a shoulder of the shaver along line  6 - 6  of FIG. 3 had the device not been exploded for illustrative purposes;  
         [0033]    [0033]FIG. 7 is a perspective view of a second, non-rechargeable embodiment of the vibratory shaver of the present invention;  
         [0034]    [0034]FIG. 8 is an exploded view of the shaver of FIG. 7;  
         [0035]    [0035]FIG. 9 is a front perspective view of a third embodiment of the vibratory shaver of the present invention shown without a razor blade attachment;  
         [0036]    [0036]FIG. 10 is an exploded perspective view of the housing therefor;  
         [0037]    [0037]FIG. 11 is a front view of the shaver of FIG. 9;  
         [0038]    [0038]FIG. 12 is a left side view thereof; and  
         [0039]    [0039]FIG. 13 is a cross-sectional view taken along line  13 - 13  of FIG. 12 through a neck of the housing. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0040]    A vibratory shaver of the present invention will now be explained by describing in detail two preferred embodiments, namely, a rechargeable battery powered shaver shown in FIGS. 1-6 and a non-rechargeable battery powered shaver shown in FIGS. 7-8. Both embodiments provide essentially the same oscillatory motion, use replaceable razor cartridges, and are identical except for the power source and housing configuration (and as otherwise noted).  
         [0041]    Referring first to FIGS. 1-3, a shaver  10  having a razor cartridge  12  rests in an upright position in a recharging cradle  14  when not in use. The cradle  14  defines a recess  15  and includes a power cord  16  which plugs into a conventional power outlet (not shown). The power cord  16  is connected to a coil (not shown) in the cradle interior for inductively charging the shaver  10 , as known in the art and described in more detail below.  
         [0042]    The razor cartridge  12  can be any straight razor blade. However, it is preferably a conventional disposable razor cartridge. The razor cartridge  12  can be mounted permanently to the shaver  10 , but is preferably removable so that it can be easily replaced when dull. The razor cartridge  12  can be mounted using any pivotal or non-pivotal connection. However, a non-pivotal connection is preferred. Thus, the razor cartridge  12  can have a back side channel (not shown) which can slide onto a straight rail  17  (preferably mounted onto or molded into the exterior of the shaver  10 ) to mount the razor cartridge  12  (see FIGS. 1 and 2).  
         [0043]    With reference to FIG. 3, the shaver  10  has a housing  18 , preferably injection molded from a suitable grade acrylonitrile-butadiene-styrene (“ABS”) plastic, defined by a front cover  20  and a back part  22 . The front cover  22  has a tactile over molded section  24  for better grip and an opening  26  for a switch button  28  to extend. The cover  20  and back part  22  are each formed with aligned unitary ribs  29  and  30  spaced apart and extending into an interior cavity  32  formed when the two parts are joined.  
         [0044]    When the front cover  20  is joined with the back part  22 , optionally by ultrasonic welding along the seam between the two parts, the housing  18  forms a hollow ergonomically contoured piece defining a handle or main body section  34 , a narrowed/neck section  36  and a broad head section  38 . As shown in FIGS. 3-6, preferably at every location along the length (or longitudinal dimension) of the shaver  10 , and at least along the neck section  36 , the housing  18  is wider (or has a greater lateral or side to side dimension) than it is deep (or in the front to back dimension).  
         [0045]    Within the body section  34  of the housing interior cavity  32  resides an electrical oscillator  40 , including a DC motor  42 , an off-center weight  44 , a rechargeable battery  46  and circuitry  48 . The motor  42  and battery  46  are fixedly mounted to the housing  18  by a mount  50 , preferably secured in place by a small amount of adhesive. The circuitry  48  couples the DC motor  42  to the battery  46  and includes a switch  52  activated by the button  28  to interrupt power to the motor  42 . The battery  46  includes a wire coil  54  connected to the positive terminal of the battery  46  such that when the shaver  10  is set into the cradle  14  it will act as the second winding of a transformer and receive by induction direct current from the coil in the cradle  14  (which is coupled to a power outlet by the power chord  16 ) through the walls of the housing  18 .  
         [0046]    This is preferred over other types of direct electric connections (such as plug and socket) because of ease of use and the ability to completely enclose the electrical components without requiring an access opening in the housing. A suitable battery  46  will provide for approximately 300 minutes 4.8 volts, which is the voltage of a preferred version of the motor  42 .  
         [0047]    Referring now to FIG. 6, when energized, the motor  42  rotates a (preferably stainless steel) shaft  56  onto which the lobe-shaped weight  44  (preferably brass) is press-fit or otherwise connected (e., by a pin, spline or key arrangement). The weight  44  is eccentrically mounted to the shaft  56  so that rather than being coaxial with the shaft  56 , its centerline and center of mass revolves around the shaft axis as the shaft  56  rotates. The revolving center of mass of the weight  44  effects a traveling moment action of the motor  42  which, by being fixed to the housing  18 , imparts an oscillating vibratory motion to the housing  18  and the razor cartridge  12 .  
         [0048]    However, the resulting oscillatory path traveled by the razor cartridge  12  is selectively directed by the construction of the housing  18  by various techniques so that the housing resists side to side motion more than front to back motion. In particular, as mentioned above, the housing  18  has a greater side to side (width or lateral) dimension (parallel to the length of the razor blades) than the front to back (depth or transverse) dimension (perpendicular to the length of the razor blades). In addition, the wall thickness of the housing  18  is greater in the lateral dimension than the front to back dimension (at least in the neck section  36  as shown in FIG. 5) and the ribs  29  and  30  having lateral sections  31  extending into the cavity  32  further in the lateral direction than front and back sections  33  extend in the front to back dimension (as shown in FIG. 4).  
         [0049]    The housing  18  is thus constructed to have increased material, and thus be more rigid, in the lateral dimension than in the front to back dimension to correspondingly limit motion side to side motion relative to front to back motion. The net result is primarily front to back oscillatory motion. This motion achieves a closer shave due to the razor blades being moved toward the surface of the skin at the base of the exposed hair follicle in an almost clawing motion. At the same time, side to side motion is low, reducing the risk of slicing cuts occurring along the skin rather than the hair.  
         [0050]    The oscillatory motion of the shaver  10  is very fine, even in the front to back direction. Preferably, the amplitude of movement in each of the front to back and side to side directions is between about 0.003 and 0.02 cm, again with the amplitude of the front to back motion being greater than that of the side to side motion. In an even more preferred range, the amplitude of the front to back motion is between 0.005 and 0.02 cm with side to side motion below 0.005 cm.  
         [0051]    Another aspect of the motion of the razor cartridge  12  is the frequency or rate of oscillation of the head and thus the razor blade. The oscillation rate may be set by the speed of the motor  42 , but with respect to some materials may be affected by the rigidity of the housing  18 . These parameters could be selected to achieve oscillation in the ultrasonic range. However, we have found that vibrations in that range can be uncomfortable to a user.  
         [0052]    We have surprisingly found a much lower rate of oscillation which achieves improved shaving, yet does not cause significant discomfort. We prefer to operate at between 100 to 200 Hertz (“Hz”) or cycles per second. Even more preferably, we prefer to operate between 100 to 150 Hz, and still more preferably at about 130 Hz.  
         [0053]    A second, non-rechargeable version of the shaver is shown in FIGS. 7 and 8. This embodiment of the shaver is essentially the same in construction and operation as the previously described embodiment, except primarily for the power source and housing configuration. Thus, many aspects of this embodiment of the invention will be described only briefly and using similar reference numerals albeit with the suffix “A”.  
         [0054]    A shaver  10 A has a razor cartridge  12 A mounted to its housing  18 A having a main body section  34 A, a narrowed neck section  36 A and a broad head section  38 A. As before, the razor cartridge  12 A is preferably a removable, conventional disposable razor cartridge, as known in the art. The housing  18 A is now three pieces, including a front cover  20 A and a back part  22 A and a base cap  23  that snaps or threads onto the assembled front cover  20 A and back part  22 A over a battery access opening  25  at the bottom end of the housing  18 A. Here, both the front cover  22 A and back part  22 A have a tactile over molded section  24 A. As before, the front cover  22 A has an opening for a switch button  28 A to extend. Again, the front cover  20 A and back part  22 A are each formed with unitary ribs (such as  30 A in back part  22 A) spaced apart and extending into an interior cavity  32 A formed when the housing  18 A is assembled. Thus, the ribs and the shape of the housing  18 A work to limit the side to side (lateral) motion to produce primarily front to back vibratory motion of the razor cartridge  12 A, like described above.  
         [0055]    As shown in FIG. 8, within the body section  34 A of the housing interior cavity  32 A is an electrical oscillator  40 A, including a weight  44 A eccentrically mounted to a rotatable shaft  56 A of a DC motor  42 A powered by a non-rechargeable battery  46 A through circuitry  48 A having on/off switch  52 A. The motor  42 A and battery  46 A are fixedly mounted to the housing  18 A by a mount  50 A. The battery  46 A preferably provides 9 volts, reduced by the circuitry  48 A to the 4.8 volts at which the motor  42 A operates. The revolving center of mass of the weight  44 A imparts a primarily front to back oscillating vibratory motion on the housing  18 A and in turn on the razor cartridge  12 A, as discussed above.  
         [0056]    A third version of the shaver is shown in FIGS. 9-13. This embodiment of the shaver is essentially the same in construction and operation as the previously described embodiment, except primarily for the housing configuration. Thus, this embodiment of the invention will be described briefly and only the housing construction will be shown in the drawings, with reference thereto using similar reference numerals as above albeit with the suffix “B”.  
         [0057]    A shaver  10 B has a two-piece housing  18 B having a front cover  20 B and a back part  22 B defining a main body section  34 B, a narrowed neck section  36 B and a broad head section  38 B. The power and motion inducing components are contained within the housing  18 B (in the main body section  34 B) and are otherwise generally the same as described above and thus will not be described here. The front cover  22 B of the housing  18 B is formed with a recess in the body section to hold a rubber grip  24 B, which here is a separate tactile component assembled by an adhesive to the front cover  20 B, rather than being an overmold, as described above. The front cover  22 B and the grip  24 B each have openings  100  and  102  for a switch button  28 B and an indicator light  103 . Like before, the front  20 B cover and back part  22 B are each formed with unitary ribs (such as  30 B in back part  22 B) spaced apart and extending into an interior cavity  32 B formed when the housing  18 B is assembled.  
         [0058]    As mentioned, this embodiment of the shaver invention primarily differs from the previously described embodiments in the configuration of the neck  36 B and head  38 B sections of the housing  18 B. In particular, the neck section  36 B is more narrow and has a more pronounced arch (shown best in FIG. 12). Even more distinguishing is the fact that the front cover  20 B terminates at a much more narrowed end and does not define a part of the head section  38 B, which instead is formed exclusively as a unitary part of the back part  22 B. The head section  38 B itself also has a different configuration than previously described. Here, the head section  38 B provides a platform for attaching a razor mount (not shown) defining two parallel rails onto which can be slid a razor cartridge having parallel grooves or tracks receiving the rails. The head section  38 B has alignment posts  104  extending in a gutter  106  which holds the razor mount between lengthwise walls  108 . A small screw can be used to secure the rail to the head section  38 B. The razor cartridge is again preferably a removable, conventional disposable razor cartridge, as known in the art.  
         [0059]    As before, the neck section  36 B is preferably hollow (except for a rib  30 B), however, it could be solid since there is no direct physical connection between the motor and the razor. As shown in FIG. 13, preferably the neck section  36 B has thicker side walls  110  than its front  112  and back  114  walls (although this may not be necessary). The thicker side walls, along with the presence of the ribs and the shape of the housing  188 B, particularly the narrow, arched neck, work to limit the side to side (lateral) motion to produce primarily front to back vibratory motion of the razor cartridge, like described above.  
         [0060]    Accordingly, the present invention provides electric shavers capable of using conventional disposable razor cartridges for wet or dry shaving. A low cost and reliable oscillator vibrates the housing to impart a short, rapid oscillatory motion to the razor cartridge. The dimensional attributes of the housing limit the side to side movement of the razor cartridge such that the net motion is predominately (has a maximum greater amplitude) front to back. The shaver thus provides a rapid and close shave.  
         [0061]    It should be appreciated that preferred embodiments of the invention have been described above. However, many modifications and variations to these preferred embodiments will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. For example, the preferred embodiments of the invention are shown and described having a hollow housing, particularly at the neck section  36 . Since no physical connection is required between the revolving weight  44  and the razor cartridge  12 , however, it is well within the scope of the invention for the neck section (or parts thereof)  36  to be formed solid, provided it retains sufficient flexibility to achieve the desired motion. The same is true from the head section  38  and parts of the body  34  as well. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced.  
       INDUSTRIAL APPLICABILITY  
       [0062]    The invention is a vibratory shaving implement providing primarily back motion of the razor head for a closer shave.