Abstract:
Replaceable shaving assemblies are disclosed that include a blade unit, an interface element configured to removeably connect the blade unit to a handle, on which the blade unit is pivotably mounted, and a return element disposed on the interface element. Shaving systems including such shaving assemblies are also disclosed, as are methods of using such shaving systems.

Description:
RELATED APPLICATIONS 
     This application is a continuation application of PCT Application Ser. No. PCT/US2013/052107, filed Jul. 25, 2013 which claims priority of U.S. Provisional Application Ser. No. 61/706,961, filed on Sep. 28, 2012. The complete disclosure of each of these applications is hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     The invention relates to shaving systems having handles and replaceable blade units. Shaving systems often consist of a handle and a replaceable blade unit in which one or more blades are mounted in a plastic housing. After the blades in a blade unit have become dull from use, the blade unit is discarded, and replaced on the handle with a new blade unit. Such systems often include a pivoting attachment between the blade unit and handle, which includes a pusher and follower configured to provide resistance during shaving and return the blade unit to a “rest” position when it is not in contact with the user&#39;s skin. 
     SUMMARY 
     Embodiments of the present invention generally provide a reusable shaving system including a replaceable shaving assembly having a pivoting blade unit, and a reusable handle on which the shaving assembly is removeably mounted. 
     In one aspect, the invention features a replaceable shaving assembly that includes a blade unit; an interface element configured to removeably connect the blade unit to a handle, on which the blade unit is pivotably mounted; and a return element disposed on the interface element. 
     Some implementations include one or more of the following features. 
     The blade unit may be pivotably mounted on the interface element by the positioning of a pair of fingers, which extend from the interface element, in receiving bores or clips disposed on the blade unit. Pivoting of the blade unit is generally about an axis that is generally parallel to the long axis of the blade unit. 
     The return element may be formed of or include an elastomer, e.g., a thermoplastic elastomer or thermoplastic urethane. 
     The return element may be configured to interact with a corresponding structure on the blade unit, e.g., a clip disposed on the blade unit under which the return element is positioned, so as to provide a return force. 
     In some cases, the return element is in the form of two bands positioned adjacent to and inboard of the fingers, in which case the corresponding structure on the blade unit includes a pair of clips, under which the return elements are positioned. Alternatively, the return element may be in the form of a single band positioned generally centrally along the length of the interface element. 
     In some cases, the return element is supported and spaced from the main surface of the interface element by support elements that extend generally perpendicularly to a long axis of the interface element. 
     Preferably, the blade unit is mounted directly on the interface element, without any intervening structures that are not integral with the blade unit. 
     In another aspect, the invention features a shaving system that includes a handle having a distal end and a proximal end; and a replaceable shaving assembly that includes a blade unit, an interface element configured to removeably connect the blade unit to a handle, on which the blade unit is pivotably mounted, and a return element disposed on the interface element. 
     This shaving system may include any of the features disclosed above or elsewhere herein. 
     In yet a further aspect, the invention features a method of shaving comprising contacting the skin with the blade unit of a shaving system comprising a handle having a distal end and a proximal end, and a replaceable shaving assembly that includes a blade unit, an interface element configured to removeably connect the blade unit to a handle, on which the blade unit is pivotably mounted, and a return disposed on the interface element. 
     Advantageously, in some implementations the return element of the shaving systems disclosed herein eliminates the need for a “pusher/follower” razor construction to provide a force to supply resistance during shaving and return the blade unit to a “rest” portion when not in contact with the user&#39;s skin. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a rear plan view of a shaving system according to one embodiment of the invention. 
         FIG. 2  is perspective view of the shaving assembly portion of the shaving system shown in  FIG. 1 . 
         FIGS. 3A and 3B  are perspective views from different directions of the interface element of the shaving assembly shown in  FIG. 2 . 
         FIGS. 4, 5A and 5B  are exploded views of the shaving assembly, showing the interface element separated from the blade unit. 
         FIG. 6  is a rear elevational view of the shaving assembly of  FIG. 2 . 
         FIG. 7  is a perspective view of a shaving system according to an alternative embodiment. 
         FIG. 8  is a perspective view of the shaving assembly portion of the shaving system shown in  FIG. 7 . 
         FIGS. 9A and 9B  are perspective views from different directions of the interface element of the shaving assembly shown in  FIG. 8 . 
         FIGS. 10-12  are exploded views of the shaving assembly, showing the interface element separated from the blade unit. 
         FIG. 13  is a rear plan view of the shaving assembly shown in  FIG. 8 . 
         FIGS. 14A  and B are diagrammatic views illustrating how the angle of the blade unit with respect to the handle at rest, and to the skin surface during shaving, is measured. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to consumer products and, in particular, to shaving systems with interchangeable blade units. In one embodiment, the present disclosure features a reusable consumer product system having an interchangeable pivoting blade unit, which includes an elastomeric return element. For example, the shaving systems disclosed herein include an interface element that provides a removable attachment between the handle and blade unit, and that includes one or more elongated elastomeric members that provide the resistance and return force usually supplied by a pusher/follower assembly. 
       FIG. 1  shows a shaving system  10  that includes a handle  12 , interface element  14  ( FIG. 2 ), and blade unit  16 , which includes a plurality of blades  15 . Blade unit  16  is pivotably mounted on interface element  14  by the positioning of a pair of fingers  18 , which extend from the interface element, in receiving bores or clips  20  which may be molded integrally with the blade unit  16  or part of a separate connector snapped onto the blade unit. Pivoting of the blade unit is about an axis that is generally parallel to the long axis of the blade unit and is generally positioned to allow the blade unit to follow the contours of a user&#39;s skin during shaving. 
     Referring to  FIGS. 14A and 14B , the angle of blade unit  16  with respect to handle  12  is about 15° at rest, and the angle of the blade unit with respect to the skin surface can range from approximately 15° to 105° during shaving. The handle  12  provides a manner in which the shaving system can be manipulated and leverage can be applied to achieve desired shaving results. 
     Generally, the interface element  14  and blade unit  16  are sold to the consumer as an integrated replaceable shaving assembly.  FIG. 2  shows the replaceable shaving assembly, including the blade unit and interface element, as it would be viewed when attaching the shaving assembly to a handle. 
     In this implementation, the return force is provided by a return element in the form of a pair of elongated resilient bands  22 . Bands  22  are disposed on the interface element, inboard of the fingers  18 , and are positioned to fit under a pair of clips  23  on the blade unit. The interaction of these bands with the clips  23  provides resistance during shaving, limiting the free pivoting of the blade unit about the pivot axis described above, and providing a return force that biases the blade unit towards its rest position, in the same manner that resistance and return are typically provided by a pusher/follower assembly. 
     The integration of the return element (bands  22 ) with the interface unit  14 , and the relatively small profile of the fingers  18  and clips  20 , provides a shaving assembly with very good rinsability. As shown in  FIG. 1 , almost the entire area behind the blades  15  is open, allowing debris to be readily rinsed out of the blade unit during use. For example, less than 20%, less than 10% or even less than 5% of the area behind the blades may be unobstructed in preferred embodiments. 
     Referring to  FIG. 3A  the two bands  22  can be integrally molded as part of a single elastomeric return element  27 . This arrangement allows the return element to be molded via a central opening in the interface piece, and provides good anchoring of the elastomer on the interface element. Anchoring is also provided by side portions  19  of the bands  22 , which are molded into corresponding underlying recesses (not shown) in the interface element. 
     Referring to  FIG. 3B , the bands  22  are each supported on the outboard side by an arm  29  from which the pin  18  extends and on the inboard side by a support  31 . This support allows the bands  22  to effectively provide an opposing force to that of the clips  23 , and prevents detachment of the bands  22  during the life of the product. 
     The return element can be formed, for example, from synthetic or natural rubber materials. Suitable materials include, for example, polyether-based thermoplastic elastomers (TPEs) available from Kraiburg HTP, thermoplastic urethanes (TPUs), silicones, and polyether-based thermoplastic vulcanizate elastomer (TPVs) available from GLS PolyOne Corporation under the tradename Santoprene™ The elastomeric material is selected to provide a desired degree of restoring force and durability. In some implementations, the elastomer has a Durometer of less than about 45 Shore A, e.g., from about 20 to 90 Shore A. 
     The bands  22  are pretensioned by a stretching of the bands that exists when the blade unit is in its at rest position. Pretensioning provides a resistance force so that a load is applied as soon as the user starts shaving, balancing the razor. The return element is generally designed such that its geometry provides an applied load as assembled that is sufficient to overcome the friction of the system at rest (pretensioned load), typically at least 5 grams, e.g., 5 to 15 grams, and a load during shaving of from about 5 to 100 grams, e.g., 10 to 50 grams. 
     Exploded views of the shaving system are shown in  FIGS. 4-5B , illustrating the manner in which the interface element and blade unit are aligned for assembly into a completed shaving assembly.  FIGS. 4 and 6  also show pivot stop  33  on the blade unit, which is integrally formed with the blade unit and which limits the pivoting of the blade unit. 
       FIGS. 7-13  show a shaving system  110  according to an alternate embodiment. This embodiment is similar to the one discussed above, except that instead of two return elements  22 , the interface element includes a single return element  122 . Return element  122  is mounted generally centrally along the length of the interface unit  114 , and is supported by and spaced from the surface of the interface unit by a pair of support members  124 A,  124 B. In this case, the blade unit  116  includes a single, central clip  123 , which engages the return element  122  in the same manner that clips  23  engage return elements  22  in the embodiment discussed above. Central clip  123  is positioned adjacent to pivot stop  133 , as shown in  FIGS. 10 and 11 . 
     A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. 
     For example, in some implementations the shaving assembly could include three or more return elements and corresponding clips, for example the interface element could include both a central return element and a pair of return elements positioned adjacent the fingers. 
     Moreover, instead of being positioned over bands  22 , as shown, clips  23  can be positioned in other manners relative to the bands, e.g., may extend through the bands. 
     As a further example, the pivoting mechanism may be different. For example, the fingers may be replaced by other types of protrusions, such as spherical members, or the entire pivoting mechanism may be replaced by a different type of pivot. Also, the pivoting mechanism may be positioned differently with respect to the bands or other return elements, e.g., in the embodiment shown in  FIG. 1  the fingers could be moved inboard of the bands, and could face towards each other, and the clips or bores engaged by the fingers relocated correspondingly. 
     Accordingly, other embodiments are within the scope of the following claims.