Patent Publication Number: US-10334744-B2

Title: Electronic subassembly for a personal care product

Description:
FIELD OF THE INVENTION 
     The present invention relates to electronic personal care products and more particularly to heated razors for wet shaving. 
     BACKGROUND OF THE INVENTION 
     Personal care products are becoming more advanced and thus often require the incorporation of electronic components to deliver new and/or improved consumer benefits. Electronic components are subject to failure when exposed to a wet environment, such as the bathroom. Furthermore, electronic components must be small to fit within a personal care product, such as a razor or a toothbrush. Accordingly, electrical components and fittings are typically very delicate and can break easily. In order to provide a safe and functional personal care product, the electrical components must be assembled and sealed against water ingress in a reliable cost-effective manner. 
     Accordingly, there is a need to efficiently assemble and seal the electronic components of a personal care product in a simple and reliable manner. 
     SUMMARY OF THE INVENTION 
     The invention features, in general, a simple, efficient method of assembling an electronic subassembly for a personal care product by manufacturing a hollow housing defining a chamber having a first open end and an opposing second open end. A rigid end of a first circuit board is inserted into the first open end of the housing. A second circuit board subassembly having a second circuit board is inserted into the chamber through the second open end. The first circuit board is connected to the second circuit board within the chamber of the housing. 
     The invention also features, in general, a simple, efficient electronic subassembly for a personal care product with a housing defining a chamber having an open end. A first circuit board having a rigid end is positioned within the chamber and a flexible portion is positioned outside the chamber. A second circuit board is positioned within the chamber. The second circuit board has a connector dimensioned to receive the rigid end of the first circuit board. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. It is understood that certain embodiments may combine elements or components of the invention, which are disclosed in general, but not expressly exemplified or claimed in combination, unless otherwise stated herein. Other features and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter that is regarded as the present invention, it is believed that the invention will be more fully understood from the following description taken in conjunction with the accompanying drawings. 
         FIG. 1  is a perspective view of one possible embodiment of a personal care product. 
         FIG. 2A  is an assembly view of an electronic subassembly, which may be incorporated into the personal care product of  FIG. 1 . 
         FIG. 2B  is a side view of the electronic subassembly of  FIG. 2A . 
         FIG. 2C  is a cross section view of the electronic subassembly, taken generally along the line  2 C- 2 C of  FIG. 2A . 
         FIG. 3  is an assembly view of a second electronic subassembly, which may be incorporated into the personal care product of  FIG. 1 . 
         FIG. 4  is an assembly view of the electronic subassembly of  FIG. 3  and the electronic sub assembly of  FIG. 2B . 
         FIG. 5  is a partial cross section view of the personal care product, taken generally along the line  5 - 5  of  FIG. 1 . 
         FIG. 6  is a partial cross section view of the personal care product, taken generally along the line  6 - 6  of  FIG. 1 . 
         FIG. 7  is a partial cross section view of the personal care product, taken generally along the line  7 - 7  of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , one possible embodiment of the present disclosure is shown illustrating a personal care product  10  having an electronic subassembly  12 . Although the personal care product  10  shown is a wet shaving razor system, it is understood that other personal care products may include, but are not limited to a foil type shaving razor, a toothbrush, a shaving brush, a powered cleansing apparatus, an epilator, and other powered personal products. These products may be used in a wet environment, such as the bathroom. In certain embodiments, the personal care product  10  may include a cartridge  14  (e.g., a shaving razor cartridge) mounted to a housing  16 . The housing  16  may act as a handle for a consumer to hold the personal care product  10 . The housing  16  may be injection molded, machined, or extruded. 
     As will be described in further detail below, the electronic subassembly  12  may comprises a first circuit board subassembly  18  and a second circuit board subassembly (not shown). The first circuit board subassembly  18  may include a first circuit board  22  having a flexible portion  24  and the housing  16  (e.g., a portion of the housing  16 ). At least a portion of the first circuit board  22  may be positioned inside the housing  16  and at least a portion of the first circuit board  22  (e.g., the flexible portion  24 ) may be positioned outside the housing  16 . In certain embodiments, the first circuit board  22  may be secured within the housing  16  by a plug  26 . As will be explained in greater detail below, the plug  26  may be part of the housing  16  and created as part of an injection molding process when the first circuit board  22  is assembled to the housing  16 . The second circuit board subassembly (not shown) may be completely contained within the housing  16 . Various electrical components may be contained within the housing  16  as part of the second circuit board subassembly (not shown). For example, the housing  16  may hold a power source, such as one or more batteries (not shown) that supply power from the second circuit board subassembly (not shown), to the first circuit board subassembly  18  and then to an electrical component  28  located outside the housing  16 . In certain embodiments, the electrical component  28  may be a heating element located on a surface of the cartridge  14  or the housing  16  to deliver heat to the skin during shaving. However, the battery in addition to, or alternatively, may supply power to other electrical components including, but not limited to motors, cooling systems and/or lights. 
     The cartridge  14  may be permanently attached or removably mounted to the housing  16 , thus allowing the cartridge  14  to be replaced. The cartridge  14  may have a guard  30 , a cap  32 , and one or more blades  34  mounted to the cartridge  14  between the cap  32  and the guard  30 . The guard  30  may be toward a front portion of the cartridge  14  and the cap  30  may be toward a rear portion of the cartridge  14  (i.e., the guard  30  is in front of the blades  34  and the cap  32  is behind the blades  34 ). The guard  30  and the cap  32  may define a shaving plane that is tangent to the guard  30  and the cap  32 . The guard  30  may be a solid or segmented bar that extends generally parallel to the blades  34 . 
     In certain embodiments, the guard  30  may comprise a skin-engaging member  36  (e.g., a plurality of fins) in front of the blades  34  for stretching the skin during a shaving stroke. The skin-engaging member  36  may be insert injection molded or co-injection molded to the cartridge  14 . However, other known assembly methods may also be used such as adhesives, ultrasonic welding, or mechanical fasteners. The skin engaging member  36  may be molded from a softer material (i.e., lower durometer hardness) than the cartridge  14 . For example, the skin engaging member  36  may have a Shore A hardness of about 20, 30, or 40 to about 50, 60, or 70. A softer material may enhance skin stretching, as well as provide a more pleasant tactile feel against the skin of the user during shaving. A softer material may also aid in masking the less pleasant feel of the harder material of the cartridge  14  against the skin of the user during shaving. 
     In certain embodiments, the blades  34  may be mounted to the cartridge  14  and secured by one or more clips  38   a  and  38   b . Other assembly methods known to those skilled in the art may also be used to secure and/or mount the blades  34  to the cartridge  14  including, but not limited to, wire wrapping, cold forming, hot staking, insert molding, ultrasonic welding, and adhesives. The clips  38   a  and  38   b  may comprise a metal, such as aluminum for acting as a sacrificial anode to help prevent corrosion of the blades  34 . Although five blades  34  are shown, the cartridge  14  may have more or fewer blades depending on the desired performance and cost of the cartridge  14 . 
     In certain embodiments, it may be desirable to provide heat in front of the blades  34 . For example, the heating element  28  may be positioned in front of the guard  30  and/or the skin engaging member  36 . The heating element  28  may comprise a skin contacting surface (e.g., a face plate) that delivers heat to a consumer&#39;s skin during a shaving stroke for an improved shaving experience. However, it is understood the heating element  28  may in addition to or alternatively supply heat to the blades  34 , either directly or indirectly. The heating element  28  may be mounted to either the cartridge  14  or to a portion of the housing  16 . 
       FIGS. 2A, 2B, and 2C  illustrate the first circuit board assembly  18 . Referring to  FIG. 2A , an assembly view of the first circuit board subassembly  18  is shown, which may be incorporated into the electronic subassembly  12  of the personal care product  10  shown in  FIG. 1 . The housing  16  may be hollow with a first open end  40  and a second open end  42 . As will be explained in greater detail below, the second open end  42  may allow for assembly of various other electrical components within the housing  16 . For example, the housing  16  may define a chamber  44  such that the second open end  42  receives the second circuit board assembly (not shown). The first open end  40  may allow for assembly of the first circuit board  22 . 
     In certain embodiments, the housing  16  may be first manufactured by an injection molding process. The housing  16  and the first circuit board  22  may then be interconnected as part of a second manufacturing operation. The first circuit board  22  may have a rigid end  46  at one end of the flexible portion  24 . The rigid end  46  may be a separate component that is mounted to the flexible portion to add stiffness and rigidity. A portion of the first circuit board  22  (e.g., the rigid end  46 ) may be placed in an injection mold along with the housing  16  and plastic (e.g., the plug  26 ) may be injected around a portion (e.g., the rigid end  46 ) of the first circuit board  22 . The plug  26  and the housing  16  may comprise the same material such that the two components form a strong bond when molded together. 
     As shown in  FIGS. 2B and 2C , the plastic plug  26  interconnects and seals the area between the first circuit board  22  (e.g., rigid end  46 ) and the housing  16 . Accordingly, the flexible portion  24  may extend outside of the housing  16  to allow for connection to other electrical components. 
       FIG. 2C  is a cross section view of the first circuit board subassembly  18 , taken generally along the line  2 C- 2 C of  FIG. 2B . As shown in  FIG. 2C , a portion of the rigid end  46  may be exposed within the housing  16  (e.g., not covered in plastic) to allow for the connection with other electronic components. The rigid end  46  may be suspending (e.g., unsupported) and extend into the chamber  44  of the housing  16 . The rigid end  46  may be sufficiently stiff such that it does not deflect once assembled (e.g., via insert molding) within the housing  16 . If the rigid end  46  deflects, it may be difficult to align and/or connect other electrical components to the rigid end  46  from within the housing  16 . This process may allow not only for sealing one end of the housing  16  form water ingress, but may also allow for the precise positioning of the rigid end  46  within the housing  16 . If the rigid end  46  is not positioned properly within the housing  16 , other electrical components may be impossible to assemble to the first circuit board  22 . 
     However, there are alternative embodiments of how to assembly the first circuit board subassembly  18 . For example, the first circuit board  22  may be placed in a mold and the housing  16  and the plug  26  may be molded to the first circuit board  22  in a single step. Alternatively, the first circuit board  22  may be insert molded with the plug  26  and then assembled to the housing  16  in a later assembly step. For example, the plug  26  may be inserted into the opening of the housing  16  and sealed using an O-ring (not shown). The first circuit board  22  may also be insert molded with the housing  16  in a single step. 
     Referring to  FIG. 3 , an assembly view of a portion of the second circuit board subassembly  20  is illustrated. The second circuit board subassembly  20  may include a second circuit board  52  and a chassis  54 . The chassis  54  may have a first end  56  and a second end  58 . The first end  56  may include a platform  60  and the second end  58  may include a battery housing  62 . The platform  60  may be flat such that the second circuit board  52  can be securely mounted to the chassis  54  (i.e., the platform  60 ). The battery housing  62  may be generally cylindrical and define an opening  64  dimensioned to receive one or more batteries  66 . The opening  64  may face in an opposite direction of the platform  60  to maximize space. In certain embodiments, the battery  66  may include a rechargeable battery. One or more electrical connectors  68 ,  70  may be used to transfer current from the battery  66  to the second circuit board  52 . The one or more electrical connectors  68 ,  70  may include power rails, clips, and/or wires. The battery housing  62  may define a channel  72  dimensioned to receive one of the electrical connectors  68 . A first end  74  of the electrical connector  68  may couple to the second circuit board  52  and a second end  76  of the electrical connector  68  may couple to a terminal  78  of the battery  66 . The other connector  70  may be used to provide an electrical connection between a second terminal  80  of the battery  66  and the circuit board  52 . A proximal end  82  of the second circuit board  52  may have a connector  84  with an opening  86  dimensioned to receive the rigid end  46  of the first circuit board  18  (not shown). 
     Referring to  FIG. 4 , an assembly view of the second circuit board subassembly  20  into the housing  16  is shown. The chassis  54  may be dimensioned to allow for easy insertion of the second circuit board subassembly  20  into the open end  42  of the housing  16 . For example, the first and second ends  56  and  58  of the chassis  54  may both have a convex surface  90  and  92  that corresponds to the geometry of the chamber  44  (not shown) of the housing  16  to help align the connector  84  of the second circuit board  52  with the rigid end  46  (not shown) of the first circuit board assembly  18  hidden within the housing  16 . The convex surfaces  90  and  92  may face in opposite directions to allow for additional room for the mounting of the second circuit board  52  to the platform  60 . In addition, the first end  56  of the chassis  54  may be tapered to guide the second circuit board subassembly  20  into the second opening  42  of the housing  16  and properly align connector  84  within the housing  16 . As will be described in greater detail below, the chassis  54  (e.g., the second circuit board  52  and/or the platform  60 ) may include one or more guide members  94 ,  96 , such as rails and/or grooves to facilitate the precise positioning of the chassis  54 , and thus the connector  84  within the housing  16  (not shown). 
       FIG. 5  is a partial cross section view of the personal care product  10 , taken generally along the line  5 - 5  of  FIG. 1 . The housing  16  may define the chamber  44  dimensioned to receive the second circuit board subassembly  20 . The guide members  94  and  96  may engage a pair of respective guide members  98  and  100 , such as channels defined by an inner surface of the housing  16 . The channels  98  and  100  may provide sufficient clearance to allow the chassis  54  to easily slide within the housing  16  and guide the connector  84  (see  FIG. 4 ) in very close proximity to the rigid end  46  (see  FIG. 2C ) of the first circuit board  22  (not shown). Accordingly, as previously shown, the guide members  98  and  100  facilitate the self-alignment of the second circuit board  52  and the connector  84  (see  FIG. 4 ) within the chamber  44  of the housing  16 . As will be explained in greater detail below, the final position of the connector  84  within the housing  16  may be facilitated by other features of the housing  16 . 
     Referring to  FIGS. 6 and 7 , the rigid end  46  is illustrated in its final assembled position within the connector  84 .  FIG. 6  is a partial cross section view of the personal care product  10 , taken generally along the line  6 - 6  of  FIG. 1 .  FIG. 7  is a partial cross section view of the personal care product  10 , taken generally along the line  7 - 7  of  FIG. 1 . The second circuit board  52  is positioned within the chamber  44  of the housing  16  by sliding it in through the opening  42  (e.g., see  FIG. 2A ) and along the rails  98  and  100  (e.g., see  FIG. 5 ). The housing  16  and the second circuit board  52  may self-align during assembly such that the connector  84  is placed in close proximity with that the rigid end  46  of the first circuit board  22 . As shown in  FIG. 6 , the housing  16  may have a plurality of ribs  102 ,  104 ,  106 ,  108  that support and guide the final connection of the second circuit board  52  (i.e., the connector  84 ) to the rigid end  46  of the first circuit board  22 . The ribs  102  and  104  may guide a top surface  112  of the connector  84 . The ribs  106  and  108  may guide a pair of side surfaces  114 ,  116  of the connector  84  and the rib  110  may guide a bottom surface  118  of the connector  84 . The ribs  102 ,  104 ,  106 ,  108  and  110  facilitate precise alignment of the opening of the connector  84  with the rigid end  46 . Accordingly, a technician can easily connect the first circuit board  22  to the second circuit board  52  without any visual aids (i.e., seeing the first circuit board  22  and the second circuit board  52  during the assembly process). The technician or assembly machine simply inserts the second circuit board into the chamber  44  of the housing  16  through the second opening  42  and the connector  84  is precisely aligned so the rigid end  46  slides within the opening of the connector  84 . No special fixtures or equipment is needed to aid in assembly. The electronic subassembly  20  also eliminates the need to utilize a more complex and costly clam shell type housing, i.e. in two halves, to connect the electronic components because a technician does not need to see the first circuit board and the second circuit board in order to properly connect the two components. In addition, insert molding a portion of the first circuit board  22  within the housing  16 , not only facilitates in alignment of the first circuit board  22  and the second circuit board  54  during assembly, but also creates a fluid seal preventing water ingress into the housing  16 . In certain embodiments, the second electronic subassembly  20  may be spaced apart from the housing  16  to allow the rigid end  46  of the first circuit board  22  to fully seat within the opening  86  of the connector  84 , thus providing a secure and reliable electrical connection. After the connector  84  and the rigid end  46  are connected, the end cap  95  (see  FIG. 4 ) may be mounted to the housing  16  to provide a fluid seal. 
     The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm”. 
     Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern. 
     While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.