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 an return element disposed between the blade unit and interface element. The return element serves as interface piece, connector and pivot all in one. Shaving systems including such shaving assemblies are also disclosed, as are methods of using such shaving systems.

Description:
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 
     In general, the present disclosure pertains to shaving systems and to replaceable shaving assemblies for use in such systems. The systems include a flexible return element, e.g., of an elastomeric material, which provides the resistance and return force that are often provided by a pusher and follower mechanism in prior art shaving systems. 
     In one aspect, the invention features a replaceable shaving assembly comprising (a) a blade unit and (b) an interface element configured to removeably connect the blade unit to a handle, the blade unit being pivotably mounted on the interface unit. The interface element comprises a flexible return element configured to provide a return force between the blade unit and handle. 
     Some implementations include one or more of the following features. The return element may be configured to bias the blade unit towards a rest position with respect to a pivot axis that is generally parallel to a long axis of the blade unit. The return element may be formed of or include a thermoplastic elastomer or thermoplastic urethane. The interface element may include a substantially rigid portion defining a cavity configured to receive a distal end of the handle. The return element may be molded onto or attached to the substantially rigid portion of the interface element. In some implementations the return element is generally U-shaped when viewed looking towards the back of the blade unit, in which case a base portion of the U-shape may be configured to engage a surface of the blade unit. The return element may be configured to bend or buckle upon rotation of the blade unit toward an upper surface of the handle. 
     In another aspect, the invention features a shaving system that includes (a) a handle having a distal end and a proximal end; and (b) a shaving assembly, mounted on the distal end of the handle, the shaving assembly including an interface element configured to connect the blade unit to the handle, and a blade unit that is pivotably mounted on the interface element. As in the first aspect, the interface element includes a flexible return element configured to provide a return force between the blade unit and handle. 
     Some implementations of this aspect of the invention may include any one or more of the features discussed above or elsewhere herein. In addition, in this aspect the shaving assembly may be either mounted removably on the handle, allowing it to be replaceable, or mounted fixedly to the handle. In the latter case, the shaving system would be designed to be disposable as a whole, rather than the shaving assembly being disposable and the handle being intended for long-term use. 
     In other aspects, the invention features methods of using the shaving systems disclosed herein. For example, the invention features a method of shaving comprising contacting the skin with the blade unit of a shaving system that includes (a) a handle having a distal end and a proximal end, and (b) pivotably mounted on the handle, a replaceable shaving assembly that includes a blade unit and an interface element configured to removeably connect the blade unit to the handle, the interface element comprising a flexible return element configured to provide a return force between the blade unit and handle. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-3  are perspective views of a shaving system according to one implementation, with the blade unit in various rotational positions. 
         FIG. 4  is an enlarged perspective view of the shaving assembly and a portion of the handle of the shaving system shown in  FIG. 1 . The longitudinal axis of the blade unit of the shaving system is indicated by line A-A. 
         FIG. 5  is an enlarged perspective view similar to that of  FIG. 4 , showing the blade unit being rotated toward the upper part of the handle, as indicated by the arrow. 
         FIGS. 5A and 5B  show the same rotational position of the blade unit from a different viewpoint. 
         FIGS. 6 and 6A  show the shaving assembly with the blade unit rotated further toward the upper part of the handle. 
         FIGS. 7 and 7A  show the handle, interface element and return element with the blade unit removed for clarity. 
         FIGS. 8A-8D  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. 
         FIGS. 9 and 10  are perspective views of shaving systems according to alternate embodiments. 
         FIGS. 11A-11C  are rear plan views of the shaving systems shown in  FIGS. 9, 1 and 10 , respectively. 
         FIG. 12  is a diagrammatic side plan view showing an example of a pivot stop that may be used in the shaving systems disclosed herein. 
         FIGS. 13-13A  are perspective views of an embodiment in which the shaving assembly is designed to be permanently attached to the handle. 
         FIGS. 14-14A  are perspective views of a handle and interface element showing an alternative geometry for the return element. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-3  show a shaving system  10  that includes a handle  12 , an interface element  14 , a return element  16 , and a blade unit  20  that includes a plurality of blades  22  ( FIG. 1 ) and that is pivotably mounted on the interface element. The interface element includes a generally rigid body that defines a cavity (not shown) dimensioned to receive the distal end of handle  12 . Generally, the interface element  14 , the return element  16 , and blade unit  20  are sold to the consumer as an integrated replaceable shaving assembly. 
     Referring to  FIG. 4 , the blade unit  20  is mounted on interface element  14  by the positioning of a pair of fingers  30  ( FIG. 7A ) which extend from the interface element  14  into receiving bores  35  ( FIGS. 5A, 5B ) on the blade unit  20 . The receiving bores  35  may be molded integrally with the blade unit  20 . This attachment allows pivoting of the blade unit with respect to the interface unit and thus the handle. A blade unit pivot stop (e.g., a stop flange  40  as shown in  FIG. 12 ) may be integrally formed with the blade unit  20  to limit the pivoting of the blade unit  20 . Pivoting of the blade unit  20  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  20  to follow the contours of a user&#39;s skin during shaving. Referring to  FIGS. 8A-8D , preferably the angle of blade unit  20  with respect to handle  12  is about 15 degrees 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. 
     The blade unit  20  is shown in three different rotational orientations in  FIGS. 1-3 . In  FIG. 1 , the blade unit is preloaded by the return element and is in an at rest position, pivoted slightly toward a bottom surface  21  of the handle; in  FIG. 2 , the blade unit is pivoted slightly toward a top surface  23  of the handle, and in  FIG. 3  the blade unit is pivoted further toward the top surface  23 . These positions are representative of the normal range of pivoting motion of the blade unit. As the blade unit pivots between these positions, the return element  16  flexes between an extended position ( FIG. 1 ) and a bent position ( FIG. 3 ), as will be discussed further below. 
     Referring to  FIGS. 7 and 7A , the return element  16  is mounted on interface element  14  and extends generally downwardly and outwardly from the lower surface  15  of the interface element. The return element  16  is generally U-shaped, and includes a generally straight central portion  17  that is configured to engage the back surface of the blade unit (e.g., as shown in  FIG. 4 ). 
     As shown in detail in  FIGS. 4-6A , as the blade unit pivots toward the upper surface of the handle, the return element  16  deforms more and more, until it finally reaches the bent position shown in  FIGS. 6 and 6A . As it deforms, the return element  16  provides resistance during shaving, limiting the free pivoting of the blade unit about the pivot axis described above. In addition, the return element  16  provides a return force that biases the blade unit  16  towards its rest position, in the same manner that resistance and return force are typically provided by a pusher/follower assembly. 
     The return element  16  may be integrally molded with the interface element  14 , e.g., by co-molding the elastomer with the rigid plastic used to form the body of the interface element. It is noted that the term “co-molding,” as used herein, includes transfer molding, multi-material molding, and other techniques suitable for molding two or more different materials into a single part. 
     The return element  16  can be formed, for example, from synthetic or natural rubber materials. Suitable materials are well known in the shaving system art, and include thermoplastic elastomers, for example, polyether-based thermoplastic elastomers (TPEs) available from Kraiburg HTP, thermoplastic urethanes (TPUs), silicones, polyether-based thermoplastic vulcanizate elastomer (TPVs) available from Exxon Mobil 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 return element  16  is designed such that its geometry provides an applied load as assembled that is sufficient to return the blade unit to its home position, e.g., against the stop on the interface element (e.g., the stop flange  40  shown in  FIG. 12 ), when not in use, for example, when the handle is being held without any load on the blade unit. Preferably the pretensioned load is typically at least 5 grams, e.g., 5 to 50 grams, and the load during shaving is from about 5 to 100 grams. 
     The handle  12  provides a manner in which the shaving system can be manipulated and leverage can be applied to achieve desired shaving results. Preferably, the handle  12  is designed to be connected to the interface element  14  so as to allow for easy removal and attachment. This could be accomplished in a number of manners, such as a mechanical locking mechanism, magnetic interaction, etc. For example, the handle interface element  14  and handle  12  can interface in the manner discussed in U.S. Ser. No. 61/651,732, filed May 25, 2012, and U.S. Ser. No. 13/802,546, filed Mar. 13, 2013, the full disclosures of which are incorporated herein by reference. Also, while the interface element is shown as a female element and the handle as a male element, the opposite configuration may be used if desired. 
     The hard portions of handle  12 , the housing of blade unit  20 , and the interface element  14  can be made of any suitable material including, for example, metal, acetal (POM), acrylonitrile butadiene styrene (ABS), polyethylene terephthalate (PET or PETE), high density (HD) PETE, thermoplastic polymer, polypropylene, oriented polypropylene, polyurethane, polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyester, high-gloss polyester, nylon, or any combination thereof. 
     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, the return element may have a different shape, for example the return element  16  is in the form of two separate fingers  42   a ,  42   b , as shown in  FIG. 9 , or by a single, centrally disposed finger  44 , as shown in  FIG. 10 . In this case, the fingers are configured to deform in the same manner described above and provide a similar restoring force. In these implementations, as well as in some implementations in which the return element is generally U-shaped, the back surface of blade unit  20  may include one or more features  46  which are positioned to act as a stop for the distal end of the return element  16 . Support features  46  may enhance the ability of the return element  16  to bend or buckle in response to rotational forces. 
     Also, while removable shaving assemblies have been discussed above, in some implementations the shaving system is designed to be disposable as a whole. In these cases, the shaving assembly is affixed to the handle in a manner that is not intended for the consumer to remove, e.g., by fixedly mounting the interface element on the distal end of the handle. This may be accomplished, for example, by engagement of corresponding mechanical locking features on the handle and interface element, by welding (e.g., ultrasonic welding), by molding the interface element integrally with the handle, or by any other desired mounting technique. An example of a disposable shaving system  100  is shown in  FIG. 13 , and the shaving assembly for such a system is shown in  FIG. 13A . In this case, the handle  112  includes protrusions  150  (only one of which is shown, the other being on the opposite side of the handle), and the interface element includes corresponding locking indentations  152 . 
     The return element may also have various shapes when seen from the side. For example, the side profile may define a single curve, as shown in  FIGS. 7 and 7A , or a double-curved, “S” shape, as shown in  FIGS. 14 and 14A . The latter shape may be used to move the return force further from the pivot point of the blade unit to better balance the blade unit during shaving. 
     Accordingly, other embodiments are within the scope of the following claims.