Abstract:
A vibrating toothbrush is provided with vibration-isolating zones that substantially isolate vibrations in the head and reduce vibrations transmitted to the handle without sacrificing structural integrity around the vibration-isolation zones. Such zones may generally comprise neck material that is reduced in cross-section, thinned, replaced by dampening material, or removed altogether to create transmission-inhibiting voids. The vibration-isolating zones may be further supported by the housing of the vibratory element to maintain the structural integrity around the zones and to thereby alleviating weakness conditions that might subject the toothbrush to fatigue and breakage conditions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 11/460,158 filed on Jul. 26, 2006 now U.S. Pat. No. 7,886,393, which claims the benefit of priority of U.S. Patent Application Ser. No. 60/702,474, filed Jul. 26, 2005, in which the contents is expressly incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a vibrating toothbrush generally, and more particularly to a toothbrush having vibrations that are isolated in the head and having reduced transmissions to the handle. 
     BACKGROUND OF THE INVENTION 
     Power toothbrushes generally comprise a power source, a motor and a powered element that is driven by the motor. In one type of power toothbrush, a power toothbrush head is provided with movable cleaning elements that are usually driven laterally, rotationally or in an oscillating manner by a motor located in the handle. The motor generates a vibration that is absorbed directly by the hands of the user. However, such vibration is effectively a byproduct of the motor operation and is usually not intended to enhance the effectiveness of the movable cleaning elements. Instead, the vibration provides a tactile sensation to the user and generally creates a perceived feeling of increased cleaning effectiveness. 
     Another type of power toothbrush relies primarily on vibrations to produce a cleaning operation. These are normally referred to as “sonic”-type brushes because the vibrations generated to achieve a high cleaning efficacy are generally of a frequency of 20-20,000 Hz that can be perceived by the human ear as a “buzz.” However, the combination of this sonic noise and the high-frequency vibration felt on one&#39;s teeth create a tactile sensation of highly increased effectiveness. To achieve the greatest cleaning, it is preferable to situate the vibration-generation device as close to the toothbrush head as possible so as to focus the vibratory energy near the site of greatest cleaning, and not along the handle. 
     In some prior art sonic-type brushes, elastomeric regions are provided between the motor and the handle to dampen the vibrations felt in the handle. However, such regions tend to decrease the structural strength of the neck and create localized weaknesses in the neck material that could subject the toothbrush to breakage or cause the toothbrush to fail cyclic fatigue tests. Dampening regions are also noticed in other vibrating-type toothbrushes near the junction of the neck and the handle, usually in the form of an elastomeric section or sections of varying configurations. However, again, such sections create structural weaknesses at a location that usually receives a significant amount of stress during use. 
     There is a need, therefore, to provide a vibration-powered toothbrush having cleaning vibrations that are directed toward or isolated in the head region and reduced in the handle region, and that do not create weakened areas that subject the toothbrush to breakage and cyclic fatigue. 
     BRIEF SUMMARY OF THE INVENTION 
     A vibrating toothbrush is provided with vibration-isolating zones that substantially isolate vibrations in the head and reduce vibrations transmitted to the handle, without sacrificing structural integrity. Such vibration-isolating zones may generally comprise neck material that is reduced in cross-section, thinned, replaced by elastic or dampening material, or removed altogether to create transmission-inhibiting voids. Such zones may be further supported by the housing of the vibratory element to maintain the structural integrity around the zones. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a side view of one embodiment of a toothbrush of the present invention; 
         FIGS. 2A and 2B  are sides views of alternative embodiments of the invention; 
         FIG. 3  is a side view of an alternative embodiment of the invention; and 
         FIG. 4  is a front view of an alternative embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The vibrating toothbrush of  FIGS. 1-4  generally comprises a handle  1 , a cleaning head  2  usually having cleaning elements  12 , and a neck  3  disposed between the head  2  and the handle  1 . While the cleaning head  2  illustrates bristles  12 , other cleaning elements of various size, cross-section, material, etc., such as rubber elements, elastomeric elements, polishing elements, abrasive elements, floss-like cleaning elements, etc., may be used. The head  2  and neck  3  are usually foamed of a relatively stiff material, such as polypropylene (PP), although other materials may be used. However, such material is also relatively elastic such that the neck and head can vibrate during use. 
     The neck  3  contains a mechanical vibratory device  5  that preferably includes a motor  10  and a vibratory element such as an eccentric weight  9  connected thereto by a shaft  11 . By methods well known in the art, the vibratory device  5  can be connected to a power source such as an electrical power source (e.g., a battery or batteries (not shown)) accommodated in the handle  1  via electrical connections  8  provided in the neck  3 , and activated by a switch (not shown). Alternatively, the power source can be located outside of the toothbrush, such as with direct current via a wall socket connection. In addition, the neck  3  can be formed as a unitary structure with the head  2  and handle  1  such as by injection molding or the like, or it can be separable from the handle  1  (not shown) preferably along location  4 . 
     The mechanical vibratory device  5  produces vibrations in the head  2  through rotation of the eccentric weight  9  about the shaft  11 . The motor  10  and eccentric weight  9  are preferably accommodated in a structural housing  15 , which is preferably positioned in the neck  3  adjacent the head  2 . The vibrations produced occur nearest the eccentric weight  9 , which is positioned closer to the head  2  than the motor  10 , which is closer to the handle  1  than the head  2 . As noted above, the neck  3  is preferably made of an elastic material which facilitates the transmission of the vibrations from the weight  9  to the head  2 . Of course, the mechanical vibratory device  5  can be positioned in a location that is not adjacent the head  2  as shown, as long as there are means to transmit the generated vibrations to the head  2 . 
     In order to reduce the transmission of vibrations below the eccentric weight  9  or toward the handle  1 , the neck construction is altered adjacent or below the eccentric weight  9  to further isolate the vibrations in the head  2 . In the embodiment of  FIG. 1 , the cross-section of the neck  3  is thinned along an exterior section  20  to reduce the amount of neck material below the eccentric weight  9 , which in turn reduces the capacity of the neck material to transmit vibrations to the handle  1 , and which in turn isolates a majority of the vibrations in the head  2 . Structural support for the thinned neck region  20  is provided by the housing  15  of the mechanical vibratory device  5 . In other words, the housing  15  reinforces the neck  3  along the thinned region  20 . As a result of the thinned neck region  20 , a noticeable increase in head vibration is achieved and transmission of vibrations to the handle  1  is minimized, all without sacrificing structural neck strength along the thinned neck region  20 . In this embodiment, it is preferable to position the thinned region  20  between the weight  9  and the base  7  of the motor  10 , and more preferably along the housing  15 , with the motor  10  and/or housing  15  providing structural support for the reduced neck cross section. 
       FIG. 2A  illustrates an alternative embodiment, wherein material is removed along an interior section  22  of the neck  3  to create one or more void spaces. The interior section  22  would not be visible to the casual observer as the outer neck wall  24  would appear to be uninterrupted. While it is preferred that the interior section  22  exist as a void with the highest vibration dampening capacity, such section may be filled with a dampening material if desired. Again, the mechanical vibratory device  5  and/or housing  15  provide the structural support for the neck  3  around the interior section  22 . 
       FIG. 2B  illustrates an alternative embodiment, wherein neck material is removed along an exterior section  26  of the neck  3  to create one or more void spaces. Such exterior section can extend between the housing  15  and an outer wall of the neck  3 . While it is preferred that the exterior section  26  exist as a void with the highest vibration dampening capacity, such section may be filled with a dampening material if desired. In the embodiments of  FIGS. 1-2B , the neck, by virtue of the sections  20 ,  22  or  26 , is reduced in cross-section by a magnitude of preferably 5%-90%, and more preferably 10%-50%. This translates into a significant reduction in the transmission of vibrations to the handle, with a significant increase in the isolation of such vibrations in the head. 
     In  FIGS. 3 and 4 , one ( FIG. 3 ) or more ( FIG. 4 ) void regions  28 ,  30  are created along the sides of the neck  3  and preferably, although not necessarily, filled with dampening material  13 . The dampening material  13  has a capacity to transmit vibrations that is less than the transmission capacity of the original neck material. For example, the neck material could be formed from PP, while the one or more void regions, which can be created by strategically removing the PP neck material, can be filled with a thermoplastic elastomer (TPE). Again, the mechanical vibratory device  5  and/or housing  15  provide the structural support for the neck  3  around the void regions  28 ,  30 . 
     In the embodiment of  FIG. 3 , for example, the rear of the neck wall can be lined with a dampening material  13  such as TPE along the entire neck region  30 , while the sides and front are formed of PP. In such embodiment, the TPE provides a dampening benefit by virtue of its material properties, but its extension beyond the boundaries of the mechanical vibratory device  5  and/or housing  15  do not create a vibration-isolating effect. Instead, additional PP neck portions  28  that are removed and retained as voids or substituted with TPE, act to isolate the vibrations from the device  5  in the head  2 , and further reduce the transmission of such vibrations to the handle  1 . If filled with TPE, these additional neck portions  28  would preferably constitute forward extensions of the dampening material  13  lining the rear of the neck wall. 
     In the embodiment of  FIG. 4 , void regions  28 ,  30  are provided on both sides of the neck  3  below the weight  9 , and are preferably filled with a material  13  having a capacity to transmit vibrations that is less than the capacity to transmit vibrations of the original neck material. A bridge  14  of neck material is defined between the regions  28 ,  30 , to structurally connect head  2  to the handle  1 . Again, the mechanical vibratory device  5  and/or housing  15  provide the structural support around the void regions  28 ,  30 .