Abstract:
A hair cutting apparatus, including a chassis to support a motor to drive a cutting blade, the apparatus comprising a rotary ring, including an inner circumferential surface, rotatably mounted on said chassis, a threaded screw, constrained within said chassis against non-rotational movement, having a head including an outer circumferential surface to engage with the inner circumferential surface of the rotary ring and a shaft including threads, the threaded screw rotating in response to the rotation of the rotary ring, a longitudinal positioner, having a socket including threads to engage with said threads of the threaded screw, to move in a longitudinal direction relative to the cutting blade in accordance with the rotation of the threaded screw, and a hair engagement comb coupled with said longitudinal positioner to position hair to be cut by the cutting blade.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is based on related Israeli Application No. 160955, filed Mar. 18, 2004, in the Israeli Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to hair clippers generally, and, more particularly, to a hair cutting apparatus, including an extendable hair engagement comb.  
         [0004]     2. Description of the Related Art  
         [0005]     Conventional hair clippers with varying cut length capability have been well known for some time. Generally, these included devices in which a movable blade is moved relative to a stationary blade for varying a cut length of hairs by moving an adjuster handle mounted on a housing of the hair clipper in a direction along the longitudinal axis of the housing. The movable blade is interlocked with the adjuster handle through a linkage member in such a manner that the movable blade is moved in a rearward direction along the longitudinal axis to reduce the cut length when the adjuster handle is moved in a forward direction along the longitudinal axis.  
         [0006]     However, since the movable blade in conventional devices is urged against the stationary blade by a torsion spring to provide a suitable spring bias to cause a hair shearing reciprocating motion of the movable blade on the stationary blade, a relatively large manipulation force is required to slide the adjuster handle and therefore the movable blade against a friction between the blades when adjusting the cut length of the hairs.  
         [0007]     In addition, the adjuster handle of the conventional devices includes a latch means capable of stably holding a shearing position of the movable blade relative to the stationary blade during the shearing operation. The latch means includes a release knob projecting on a portion of the adjuster handle to be accessible by a finger of an operator manipulating the handle. The release knob is provided to unlatch the adjustor handle upon being pressed to thereby permit a sliding movement of the handle for varying the cut length. Eventually, the operator is required to press the release knob for sliding the adjuster handle besides the above described manipulation force. This is inconvenient and is therefore a cause of accumulating fatigue of a wrist or fingers of the operator when shearing the hairs while varying the cut length continuously and manually. Additionally, it may be expected that such linkage member and latch means create difficulties because of necessary complex structures.  
         [0008]     These problems have been addressed in hair clippers that have a cutter head on the front end of a housing which includes a toothed stationary blade and a toothed movable blade reciprocating on the stationary blade in a hair shearing engagement between individual toothed edges thereof. The movable blade is slidable relative to the stationary blade in an edgewise direction perpendicular to the reciprocating motion of the movable blade for varying a cut length of hairs. An adjuster handle is slidably fitted on an outer round surface of the housing and linked to the movable blade through a linkage member such that the movable blade is shifted in the edgewise direction to increase and reduce the cut length by rotating the adjuster handle about a longitudinal axis of the housing.  
         [0009]     However, since the cutting blade is moved relative to the stationary blade, the ability to cut hair at any particular length is limited to the distance between the stationary blade from the housing, which is predetermined at the time of manufacture and which is necessarily relatively short relative to desired hair lengths for many people.  
         [0010]     Further, since the hair-cutting blade is moved relative to the body of the device, the blade may be damaged during the course of the lifetime of the blade, resulting in lowered reliability and cutting efficiency.  
       SUMMARY OF THE INVENTION  
       [0011]     An aspect of the present invention provides a hair cutting apparatus, comprising a chassis to support a motor to drive a cutting blade, a rotary ring, including an inner circumferential surface, rotatably mounted on said chassis,a threaded screw having a head including an outer circumferential surface to engage with the inner circumferential surface of the rotary ring, and a shaft including threads, the threaded screw rotating in response to the rotation of the rotary ring, a longitudinal positioner having threads to engage with said threads of the threaded screw, to move in a longitudinal direction relative to the chassis in accordance with the rotation of the threaded screw and a hair engagement comb coupled with said longitudinal positioner to position hair to be cut by the cutting blade.  
         [0012]     Another aspect of the invention provides a hair cutting apparatus, including a chassis to support a motor to drive a cutting blade, the apparatus comprising a rotary ring, including an inner circumferential surface, rotatably mounted on said chassis, a threaded screw, constrained within said chassis against non-rotational movement, having a head including an outer circumferential surface to engage with the inner circumferential surface of the rotary ring and a shaft including threads, the threaded screw rotating in response to the rotation of the rotary ring, a longitudinal positioner, having a socket including threads to engage with said threads of the threaded screw, to move in a longitudinal direction relative to the chassis in accordance with the rotation of the threaded screw, and a hair engagement comb coupled with said longitudinal positioner to position hair to be cut by the cutting blade.  
         [0013]     Another aspect of the invention provides a hair cutting apparatus, including a chassis to support a motor to drive a cutting blade, the apparatus comprising a rotary ring, including an inner circumferential surface, rotatably mounted on said chassis, a threaded screw, constrained within said chassis against non-rotational movement, having a head including an outer circumferential surface to engage with the inner circumferential surface of the rotary ring and a shaft including threads, the threaded screw rotating in response to the rotation of the rotary ring, and a longitudinal positioner, having a socket including threads to engage with said threads of the threaded screw, to position a hair engagement comb at a desired distance from the cutting blade in accordance with the rotation of the threaded screw.  
         [0014]     Another aspect of the invention provides a hand held hair cutting apparatus, including a cutting assembly, comprising a first member, disposed on a surface of the apparatus, to be selectively moved by a user in forward and reverse directions, a second member, disposed within the apparatus, to transform the movement of the first member into linear movement relative to the cutting assembly, and a third member, extending from the second member to an exterior of the apparatus, to position a hair engagement device a distance from the cutting assembly in accordance with the selection of the user.  
         [0015]     Still yet another aspect of the invention provides a method of operating a hand held hair cutting apparatus, including a cutting assembly, comprising selectively moving a first member, disposed on a surface of the apparatus, in forward and reverse directions, transforming the movement of the first member into linear movement based on an amount of the selective movement of the first member relative to the cutting assembly, and positioning a hair engagement device a distance from the cutting assembly in accordance with the linear movement.  
         [0016]     Additional and/or other aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
         [0018]      FIGS. 1A and 1B  are illustrations of an extendable hair-clipping device constructed and operative in accordance with an embodiment of the present invention in a retracted orientation and an extended orientation, respectively;  
         [0019]      FIG. 2  is an exploded view illustration of the hair-clipping device of  FIGS. 1A and 1B ;  
         [0020]      FIG. 3  is an illustration of a comb driving assembly in operative association with a hair length control ring and a hair engagement comb which form part of the hair-clipping device of  FIGS. 1A-2 ;  
         [0021]      FIGS. 4A and 4B  are respectively, a pictorial illustration and a sectional illustration of a hair length control ring, the sectional illustration being taken along section lines IVB-IVB in  FIG. 4A ;  
         [0022]      FIGS. 5A and 5B  are respectively a pictorial illustration and a side view planar illustration of the operative engagement between teeth on a screw head and teeth on an array on the hair length control ring of  FIGS. 4A and 4B ;  
         [0023]      FIGS. 6A, 6B  and  6 C are respectively, a pictorial illustration, a top view planar illustration and a sectional illustration of a slidable longitudinal positioner, which forms part of the hair-clipping device of  FIGS. 1A-2 , the sectional illustration being taken along section lines VIC-VIC in  FIG. 6B ;  
         [0024]      FIGS. 7A and 7B  are respectively top and bottom pictorial illustrations of a hair engagement comb which forms part of the hair clipper device of  FIGS. 1A-2 ;  
         [0025]      FIGS. 8A and 8B  are pictorial illustrations of the hair length control ring in operative association with the comb driving assembly and the hair engagement comb mounted onto the main chassis of  FIG. 2 , showing hair engagement comb in retracted and extended orientations, respectively;  
         [0026]      FIG. 9  illustrates a hand-held hair cutting apparatus in accordance with an embodiment of the invention; and  
         [0027]      FIG. 10  is a flow chart to describe a method of operating a hand-held hair cutting apparatus in accordance with an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0028]     Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.  
         [0029]     Reference is now made to  FIGS. 1A and 1B , which are pictorial illustrations of an extendable hair-clipping device constructed and operative in accordance with an embodiment of the present invention in a retracted orientation and an extended orientation respectively and to  FIG. 2  which is an exploded view illustration of the hair-clipping device of  FIGS. 1A and 1B .  
         [0030]     As seen in  FIGS. 1A, 1B  and  2 , the hair-clipping device comprises a generally conical rear housing portion  100  that is arranged about a longitudinal axis  102 . The rear housing portion  100  partially encloses a main chassis  104 . The main chassis  104  supports a motor  106 , a screw head socket  107  and a battery  108  to power the motor. The motor  106  drives a cutting blade assembly  110  in a reciprocating cutting motion. The construction and operation of the motor  106  is well known in the art. Elongated axial edges  111  and elongated side supports  112  are also formed on the main chassis  104 .  
         [0031]     A rotatable hair length control ring  114  is rotatably mounted onto a forward edge  113  of rear housing portion  100 . The rotatable hair length control ring  114  selectively positions a hair engagement comb  116  along an axis  102  in variable positions along a longitudinal direction. A rotatable motion of hair length control ring  114  about the axis  102  is converted to longitudinal motion of the hair engagement comb  116  about the axis  102  by a comb driving assembly  120 , which is located within a forward housing portion  122 .  
         [0032]     A cutting blade assembly  110  is located at a forward end of forward housing portion  122  and the hair engagement comb  116  is located forwardly of the cutting blade assembly  110  along the longitudinal axis  102  by a selectable distance related to an amount of the rotation of the hair length control ring  114 , as seen in  FIGS. 1A and 1B , which is to be determined by a user. An electric motor on-off switch  124  is also mounted onto forward housing portion  122  and which will be described below.  
         [0033]     With reference to  FIG. 3 , which is a simplified pictorial illustration of the comb driving assembly  120  in operative association with the hair length control ring  114  and the hair engagement comb  116 , the comb driving assembly  120  comprises a threaded screw  130  having a head  132 , which is formed with gear teeth  133 . The threaded screw  130  is disposed to be driven in a rotational direction as a result of an engagement between the threaded screw  130  and the hair length control ring  114 .  
         [0034]     The threaded screw  130  engages a slidable longitudinal positioner  134  including a support portion  136  and an elongated portion  138  which is formed with a threaded socket  140 . A threading pattern of the threaded socket  140  generally corresponds with that of the threaded screw. A forward end of elongated portion  138  may engage with an extension portion  142  of the hair engagement comb  116  in a snap fit engagement.  
         [0035]     Thus, a manual rotation of the hair length control ring  114  produces a corresponding rotation of the threaded screw  130 . This, in turn, produces a longitudinal displacement of the longitudinal positioner  134  along the axis  102 .  
         [0036]     It is understood that the tooth-to-tooth engagement between the threaded screw  130  and the array  150  of teeth  152  of the hair length control ring  114  is only one embodiment of the invention. An alternate embodiment, in which the outer surface of the threaded screw  130  and the inner surface of the hair length control ring  114  comprise frictional surfaces that contact with each other, is possible. According to this embodiment, a rotation of the hair length control ring  114  causes a corresponding rotation of the threaded screw  130  due to the frictional contact between the outer and inner surfaces of the hair length control ring  114  and the threaded screw  130 . Of course, yet additional embodiments, which provide for similar effects, are also possible.  
         [0037]     Reference is now made to  FIGS. 4A and 4B  which illustrate the hair length control ring  114 . As seen in  FIGS. 4A and 4B  the hair length control ring  114  is generally cylindrical ring-shaped and includes an array  150  of teeth  152  arranged along an inner circumferential surface  154  thereof, which is located along a rearward-facing flange  156 . Rearward-facing flange  156  is configured for rotational sliding engagement with forward edge  113  of rear housing portion  100 . According to an embodiment of the invention, the array  150  extends along most, but not all, of the extent of circumferential surface  154  so as to define an extent of the rotation of the threaded screw  130  and, thus, of the longitudinal travel of the hair engagement comb. A row of square protrusions  155  may be located forwardly of the array  150 , according to an embodiment of the invention, and extends along the extent of the circumferential surface  154 . The row  155  is configured to provide resistance to rotation of hair length control ring  114 .  
         [0038]     An outer surface  158  of the hair length control ring  114  may be formed with dimples  160  to enhance a frictional engagement therewith by the fingers of the user. A forward facing flange  162  may be provided for rotational sliding engagement between the hair length control ring  114  and a corresponding rearward facing edge of the forward housing  122 .  
         [0039]     Reference is now made to  FIGS. 5A and 5B , which illustrate the operative engagement between the teeth  133  of the screw head  132  and the teeth  152  of the array  150  on ring  114 . As is illustrated, the threaded screw  130  is constrained against longitudinal movement along the axis  102  by the encasement of the screw head  132  in the screw head socket  107  of the main chassis  104 . Thus, the rotation thereof in the threaded socket  140  produces a corresponding longitudinal displacement of the positioner  134 .  
         [0040]     Reference is now made to  FIGS. 6A-6C , which illustrate the slidable longitudinal positioner  134 . As is noted above, the positioner  134  includes the support portion  136  and elongated portion  138 , which is formed with the threaded socket  140 , whose threading generally matches that of the threaded screw  130 . The support portion  136  includes slotted edges  170  which are configured for longitudinal sliding engagement with corresponding elongated edges  111  of the main chassis  104 .  
         [0041]     Reference is now made to  FIGS. 7A and 7B , which illustrate the hair engagement comb  116 . As is described hereinabove with reference to  FIG. 3 , the extension portion  142  of the hair engagement comb  116 , is configured with a snap fit socket  143  to provide for the engagement between the hair engagement comb  116  with a forward end of the elongated portion  138  of the slidable longitudinal positioner  134 . The extension portion  142  has elongated edge protrusions  144 , configured for longitudinal sliding engagement within the elongated side supports  112  that are formed on the main chassis  104 .  
         [0042]     Reference is now made to  FIGS. 8A and 8B  which show the hair length control ring  114  in operative association with the comb driving assembly  120 , the hair engagement comb  116  and the main chassis  104 . As seen in  FIGS. 8A and 8B , respective retracted and elongated positions of the hair engagement comb  116  correspond to respective first and second rotational orientations of hair length control ring  114 . A rotation of the hair length control ring  114  is converted to an axial displacement of hair engagement comb  116  by the engagement of array  150  of the teeth  152  with the head  132  of the threaded screw  130 , producing rotation thereof. Since the threaded screw  130  is constrained against a longitudinal movement along the axis  102  by the screw head socket  107 , a rotation thereof in the threaded socket  140  produces a corresponding longitudinal displacement of the positioner  134  and, thus, a displacement of the hair engagement comb  116 .  
         [0043]     Various mechanisms in addition to the row of protrusions  155  to hold the hair engagement comb  116  in place relative to the forward housing  122  will now be described with reference to methods of operation of the hair clipping device of the present invention. First, once a user has positioned the hair engagement comb  116  in a desired position and thereafter begins cutting a hair cutting operation, it is understood that a compressing force applied to the hair engagement comb  116  to tend to cause the hair engagement comb  116  to move toward the forward housing  122  will be applied by the surface of a body undergoing the hair cutting operation. According to an embodiment of the invention, however, an angle and friction generated between the corresponding threads of the threaded screw  130  and the threaded socket  140  as well as the friction generated between the teeth  152  of the array  150  and the teeth  133  of the screw head  132  combine to prevent a compression of the hair engagement comb  116  toward the forward housing  122  under a compressing force applied by the body.  
         [0044]     According to other embodiments of the invention, a compression of the hair engagement comb  116  toward the forward housing  122  may be prevented by a latch system and/or a locking system which selectively disengages the threaded screw  130  from either the threaded socket  140  or the array  150  of teeth  152  and/or prevents a rotation of either the threaded screw  130  and the array  150  of teeth  152  or a longitudinal movement of the threaded socket  140 .  
         [0045]     It is understood that such a latch system and/or a locking system may provide either predetermined cutting positions at which the hair clipping device may be set, or may allow a user to set a hair cutting length at any length given the length of the extension portion  142  of the hair engagement comb  116 .  
         [0046]     With respect to  FIG. 9 , an aspect of the invention is illustrated. According to this embodiment, a hand held hair cutting apparatus  1 , including a cutting assembly  2 , comprises a first member  3 , disposed on a surface  4  of the apparatus  1 , to be selectively moved by a user in forward and reverse directions (designated by arrows A and B), a second member  5 , disposed within the apparatus  1 , to transform the movement of the first member  3  into linear movement relative to the cutting assembly  2 , and a third member  6 , extending from the second member  5  to an exterior of the apparatus  1 , to position a hair engagement device  7  a distance L from the cutting assembly  2  in accordance with the selection of the user. It is understood that the operation of the second member  5 , in particular, may be understood in light of the above-described embodiments, and, additionally, in view of the fact that these embodiments are not limiting and that there are additional arrangements and structures that are available.  
         [0047]     With respect to  FIG. 10 , a method of operating a hand held hair cutting apparatus, including a cutting assembly, comprises (operation  1000 ), transforming the movement of the first member into linear movement based on an amount of the selective movement of the first member relative to the cutting assembly (operation  2000 ); and positioning a hair engagement device a distance from the cutting assembly in accordance with the linear movement (operation  3000 ).  
         [0048]     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.