Patent Publication Number: US-6901664-B2

Title: Hair clipper and seal

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to hand held clippers for trimming hair and the like. More particularly, the present invention is related to seals for sealing a gap in an electric hand held clipper housing, as well as to clippers having a seal for sealing a housing gap. 
   Hand held clippers for trimming and shearing hair are generally known in the art. Conventional clippers typically include a housing that contains a motor, with the motor drivingly attached to a blade assembly for trimming or cutting the hair. The blade assembly typically has a reciprocating blade that cooperates with a fixed blade to trim or clip hair. The housing may have a front opening for passing an operative portion of the fixed and moving blades. A gap generally exists between the blade assembly and the housing. This gap can have several disadvantages associated with it. 
   For example, the gap may be proximate the operating portion of the blades and therefore be regularly exposed to cut portions of hair. The hair cuttings can enter the clipper housing through the gap and can be harmful to operation of the clipper. Cuttings can become tangled between the moving and non-moving blade, increase friction between the two blades, and over time may even shorten the stroke of the moving blade. Hair cuttings can likewise interfere with operation of the motor and its linkage to the moving blade. Further, hair cuttings can trap dust, grease, and other debris. These and other problems with hair cuttings are particularly troublesome because hair cuttings are notoriously slow to decompose and difficult to disengage once entangled. These problems can result in the need for frequent disassembly and cleaning of clippers, and if not effectively addressed can lead to a substantially shortened clipper service life. 
   Some solutions to these problems have been proposed in the past. To date, however, the proposed solutions have been deficient. For example, a proposed solution has been to secure an insert in the gap using an adhesive. Often a foam insert has been used. While such foam inserts may limit entry of hair into the clipper housing for a period of time, experience has suggested them to be limited in effectiveness and service life. For example, some foam inserts tend to disintegrate after a period of use and to thereby re-open the gap for entry of hair cuttings. Also, disintegration may cause small portions of the foam to come loose, with these small portions potentially interfering with clipper operation in the same way that the hair cuttings do. Other types of foam inserts have been known to collect hair in the foam itself to the extent that clipper operation may be impaired. 
   Further, the adhesive used to secure an insert of the prior art can have a tacky surface that may disadvantageously attract and retain hair cuttings. This can be particularly troublesome when the adhesive surface gradually becomes exposed over time as the foam disintegrates. Also, the adhesives holding some inserts in place tend to weaken with age and use, with the result that the insert may come loose. 
   In addition to these problems, foam inserts have proven to be difficult to replace. Because the service life of the foam insert is often considerably shorter than that of the clipper, consumers must be relied upon to replace the inserts. This is disadvantageous because many users either do not have the expertise to replace the inserts or are not willing to go to the effort of replacing the inserts. As a result, clippers with foam inserts may have less than satisfactory operation and may suffer a shortened service life. 
   Finally, some clippers are intended to be used with different blade sizes and geometries. For example, a particular clipper may be designed to fit any of a plurality of interchangeable blade assemblies of different sizes. Each of these blades may have different geometries that result in the gap between them and the housing to be different. Known inserts are generally not able to effectively accommodate these different gap sizes. 
   Unresolved problems in the art therefore remain. 
   SUMMARY OF THE INVENTION 
   One embodiment of the present invention is directed to a seal for a hand held hair clipper. In particular, an invention embodiment is a seal for use with a hand held clipper of the type that has a blade assembly and a housing, with a gap defined between the blade assembly and the housing. The seal includes a sealing portion that has a housing engaging side for engaging an interior surface of the clipper housing and an opposite blade engaging side for engaging at least a portion of the clipper blade assembly. A base portion is provided for attaching the seal to the housing. 
   An additional embodiment of the invention is directed to an electric hair clipper having a housing that contains an electric motor with a blade assembly operatively linked to the motor. The housing has an opening for passing a portion of the blade assembly. A gap is defined in the opening between the blade assembly and the housing. The housing has an interior surface and at least one interior boss. A molded thermoplastic seal is provided for sealing the gap, with the seal having at least one attachment tab for mating with the at least one boss. 
   Embodiments of the present invention thereby offer a solution to many of the otherwise unresolved problems of the prior art. For example, a molded thermoplastic seal offers advantages of resiliency and a longer service life than foam seals of the prior art. Additionally, attaching a seal of the invention to the clipper housing with an attachment tab solves many problems associated with the use of adhesives with prior art seals. Those skilled in the art will appreciate that embodiments of the present invention offer many other advantages and resolve other problems of the prior art, as will be better detailed below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a preferred embodiment of a seal of the invention; 
       FIG. 2  is a front view of the seal of  FIG. 1  taken along the line  2 — 2  of FIG.  1  and in the direction generally indicated; 
       FIG. 3  is a rear view of the seal of  FIG. 1  taken along the line  3 — 3  of FIG.  1  and in the direction generally indicated; 
       FIG. 4  is a top view of the seal of  FIG. 1  taken along the line  4 — 4  of FIG.  3  and in the direction generally indicated; 
       FIG. 5  is a bottom view of the seal of  FIG. 1  taken along the line  5 — 5  of FIG.  3  and in the direction generally indicated; 
       FIG. 6  is a side view of the seal of  FIG. 1  taken along the line  6 — 6  of FIG.  5  and in the direction generally indicated; 
       FIG. 7  is an exploded perspective view of a portion of a clipper of the invention; 
       FIG. 8  is a bottom perspective view of an upper housing portion with the present seal installed; 
       FIG. 9  is an exploded perspective view of the present clipper; and 
       FIG. 10  is a fragmented vertical cross-section of the present clipper. 
   

   DETAILED DESCRIPTION 
   Turning now to  FIGS. 1-6 , a preferred seal shown generally at  10  has a sealing portion  12  integral with a base portion  14 . The seal  10  is preferably made of a molded plastic, and most preferably a flexible, rubber-like elastomer such as neoprene. The sealing portion  12  has a housing engaging side  16  for engaging a clipper housing and an opposing blade engaging side  18  for engaging a clipper blade assembly. When the sealing portion  12  is so engaged in a clipper, the gap between a blade assembly and housing is sealed and thereby blocked from entry of hair cuttings. 
   Two elongate projections  20  extend upwards from the housing engaging side  16  to define a channel therebetween. In the preferred embodiment, two projections  20  are located adjacent an edge  21  of the housing engaging side  16 . However, it is contemplated that the location, number, and precise configuration of the projections  20  may vary to suit a particular application. For example, only one projection is contemplated. The preferred projections  20  are relatively thin and pliable, and thereby readily adapt to the particular size of a gap between a blade assembly and housing. For example, the projections  20  may be substantially compressed against a housing interior surface when a relatively large blade assembly is installed, and may be relatively un-compressed when a smaller blade assembly is present. Providing at least two projections  20  minimizes the chances of an ineffective seal. 
   Two arms  22  extend in a generally rearward direction from the base portion  14  opposite the edge  21  and each has a generally vertical wall  24  descending therefrom. An attachment formation, preferably having the shape of an attachment tab  26 , is connected to the base of at least one and preferably both of the walls  24 . The attachment formation or tab  26  is for releasably attaching the seal  10  to a housing interior surface. The tab  26  may be releasably engaged to hold the seal  10  in place when it is “pinched” between cooperating housing structures upon assembly of the housing. Additionally, a throughbore  28  extends through each of the attachment tabs  26  for engaging a housing boss. 
   Many alternative configurations to the tabs  26  and throughbores  28  will be obvious to those knowledgeable in the art. By way of example and not limitation, attachment means for releasably attaching the seal to the housing such as an open, U-shaped throughbore, clips, lugs, mating hooks and loops, and the like could readily be practiced with other embodiments of the invention. Also, it will be appreciated that the arms  22  are preferred only, and that other invention embodiments may have attachment means that are not connected to the seal via the arms  22 . 
   The base portion  14  preferably has a generally arcuate shape in a cross direction, as best illustrated by  FIGS. 2-3 . As used herein, the cross direction will refer to the direction generally parallel to the axis of the extensions  20 , while the longitudinal direction will refer to the direction generally parallel to the direction in which the arms  22  extend outward from the base portion  14 . This arcuate shape is provided to generally match the contour of the upper housing  52  so as to provide an effective seal. It has also been discovered that the arcuate shape of the base portion  14  benefits the sealing function of the seal  10  in that it contributes a degree of stiffness to the generally flexible seal  10 , and may also provide a pre-load or spring force. The stiffness and spring force are useful in urging the seal portion  12  into engagement with the blade assembly and housing. 
   Also, the sealing portion  12  is preferably thinner than the base portion  14 . A thicker base portion  14  provides for strength and some degree of rigidity useful for urging the sealing portion  12  into place. A thinner sealing portion  12  is preferable for providing greater flexibility and pliability so that different blade sizes and geometries can be effectively engaged. At least a portion  30  (best seen in  FIG. 6 ) of the blade engaging side  16  has a generally concave shape when viewed from the side for engaging a portion of a clipper blade assembly. Engagement with a portion of the clipper blade assembly will advantageously urge the seal  10  upwards into engagement with the clipper housing. 
   Referring now to  FIGS. 7-10 , the various elements of the seal  10  and their functions can be better illustrated through discussion of a preferred clipper generally designated  50  that uses a seal generally consistent with the seal  10 . The clipper  50  has a housing that has upper and lower portions  52  and  54 , respectively. The housing portions  52  and  54  are preferably made of a molded plastic selected for durability, cost, and the like as is known in the art. The housing contains an electric motor  56  (FIG.  9 ), which is connected to an AC power supply (not shown) by the cord  58 . Those knowledgeable in the art will appreciate that a DC power supply, such as a battery, could alternatively be provided. The housing upper portion  52  has an interior surface  60  ( FIGS. 7 and 8 ) having a pair of generally cylindrical depending bosses  62  and support walls  63 . The particular shape, number, and location of the bosses  62  and walls  63  may vary to suit a particular application. The bosses  62  may be provided for the purpose of anchoring the seal  110 . It is also contemplated, however, that the bosses  62  may be used for receiving a fastener such as a stud, screw, or the like that may be provided to attach the lower housing portion  54  to the upper housing portion  52 . Those knowledgeable in the art will understand that housing portions  52  and  54  may include other structures and features, such as additional bosses, studs, support walls, and the like. Because these other structures and features are generally known, they will not be discussed herein for sake of brevity. 
   Referring now to  FIGS. 9 and 10 , the motor  56  is connected to a blade assembly shown generally at  64 , which includes a fixed blade  66 , a moving blade  68 , and a tensioning spring  70  that urges the moving blade  68  into operative engagement with the fixed blade  66 . Preferably, the clipper  50  may be used with any of a plurality of interchangeable blade assemblies  64 , which may each be of different sizes or tooth configurations. As is typical in the art, the motor  56  is linked to the blade assembly  64  to cause the moving blade  68  to reciprocate in the cross direction. Hair may thereby be cut through a scissor-like action between cooperating teeth  69  at a cutting end  78  of the two blades  66  and  68 . The tensioning spring  70  has at least a portion  72  that is generally arcuately shaped for providing spring force to urge the moving blade  68  into engagement with the fixed blade  66 . The arcuately shaped portion  72  of the tensioning spring  70  is preferably movably received by the moving blade  68  so that the spring remains generally stationary while the blade  68  reciprocates. 
   As best illustrated by  FIG. 9 , the blade assembly  64  is installed in the assembled housing portions  52  and  54  by attaching the fixed blade  66  to a stud  74  and positioning the blade assembly  64  so that a cam drive  76  driven by the motor  56  is coupled to the moving blade  68 . As best illustrated by  FIG. 10 , after installation the cooperating cutting teeth  69  of the blades  66  and  68  extend out of an opening  80  that is defined by the housing portions  52  and  54 . 
   The seal shown generally at  110  effectively seals a gap defined between the blade assembly  64  and a perimeter edge of the housing opening  80 . The seal  110  is generally consistent with the seal  10  illustrated in  FIGS. 1-5 . For convenience, element numbers consistent with those used for the seal  10  have been used in the 100 series for the seal  110 . As best shown by the cross section of  FIG. 10 , a sealing portion  112  has a blade engaging side  116  that engages the blade assembly  64 , and a housing engaging side  118  that engages a portion of the interior surface  60  of the housing portion  52 . At least a portion  130  of the blade engaging side  116  has a generally concave shape in the longitudinal direction adapted to receive the arcuate portion  72  of the tensioning spring  70 . 
   When the spring  70  engages the blade engaging side  116  of the flexible seal  110 , it urges the spring upwards into engagement with the housing interior surface  60 . The base portion  114  is preferably thicker than the sealing portion  112 . In combination with its cross direction arcuate shape, this advantageously provides the base portion  114  with a degree of stiffness useful to urge the more flexible sealing portion  112  into effective sealing position between the blade assembly  64  and the housing interior surface  60 . A thinner sealing portion  112  is advantageous so that the sealing portion is relatively flexible to accommodate use of different interchangeable blade assemblies  64 , as well as tolerances in blade assemblies  64  and housings. Preferably, the thickness of the seal  110  is generally tapered from a front side  121  of the thinner sealing portion  112  moving rearwards to a back edge of the thicker base portion  114 . 
   As best shown by  FIG. 10 , when the seal  110  is in place, contact with the tensioning spring  72  urges the housing engaging side  118  and its two pliable, elongate projections  120  into contact with the housing interior surface  60 . The projections  120  on the engaging side  118  may thereby be compressed and flattened to insure effective sealing. The degree to which they are compressed will depend on the size of the blade assembly  64 . The ability of these flexible projections  120  to compress by differing amounts further enhances the seal&#39;s  110  ability to accommodate different interchangeable blade assemblies  64 . For example, one blade assembly  64  may require little or no compression of the projections  120 , while a second larger blade assembly  64  may require the projections  120  to be more substantially compressed. 
   Two arms  122  extend in a rearward direction from the base  114 , with a generally vertical step or wall  124  at an end of the arms  122 . An attachment formation or tab  126  is connected to the arms  122  and the wall  124  and is used to attach the seal  110  to the housing portion  52 . Each of the attachment tabs  126  has a throughbore  128  for mating with one of the bosses  62 , as best illustrated by  FIG. 7  that shows the seal  110  being installed on the upper housing portion  52 , and by  FIG. 8  that shows the seal  110  installed. The boss  62  is received in the throughbore  128 . This generally prevents movement of the seal  110  in a forward and reverse direction in relation to the clipper  50 . To further lock the seal  110  in place, the clipper upper housing portion  52  is provided with a pair of support walls  63  that each has a slot  65  for receiving one of the attachment tabs  126 . A pair of locking walls  67  are provided on the lower clipper housing portion  54  for cooperating with the support walls  63 . When the two housing portions  52  and  54  are assembled, the locking wall  67  holds the attachment tab  126  in place in the slot  65  in a “pinching” manner as is illustrated by FIG.  10 . It is also contemplated that the slot  65  could be formed in the locking wall  67 , or that the walls  63  and  67  are configured to engage the tab  22  without provision of the slot  65 . 
   This attachment configuration has been discovered to offer several advantages over the prior art. For example, the present attachment configuration renders the seal  110  securely “trapped” in place once the housing is assembled. The chance of the seal  110  coming unattached is minimal. No tools, adhesives, screws or other fasteners are required for attachment. Replacement of the seal  110  is therefore a straightforward task. 
   Those skilled in the art will appreciate that the preferred seal and clipper embodiments described herein have been discussed for illustration purposes only. Other embodiments are of course possible within the scope of the invention. Indeed, those knowledgeable in the art will recognize equivalents to elements of the described preferred embodiment that are within the scope of the claimed invention. 
   Various features are set forth in the appended claims.