Abstract:
A reciprocating device used for electric hair cutter includes a housing, a magnetism transmitting unit, a coil unit, a reciprocating unit, a pivotal unit and a stationary magnet unit. After the coil unit is fitted to the magnetism transmitting unit, the former is partially surrounded by the latter. Through the pivotal unit, the reciprocating unit is pivotally fitted to the reciprocating device near the latter&#39;s rear or front end. The front or rear portion of the reciprocating unit passes through the magnetism transmitting unit. The other end of the reciprocating unit passes through the stationary magnet unit. In this manner, a portion of the reciprocating unit is housed or enclosed in the magnetism transmitting unit, allowing a reduction in the size of the prior art reciprocating device and hence the electric hair cutter in the prior art.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention generally relates to an electric hair cutter. More particularly, the invention relates to a reciprocating device used for an electric hair cutter. 
         [0003]    2. Description of the Prior Art 
         [0004]      FIG. 1  is a top view of a prior art electric hair cutter (Taiwan Patent No. M369,233, with the title of “Improved Reciprocating Cutting Unit for Electric Hair Cutter”). In the electric hair cutter  70 , hair is cut by the relative lateral motion of a mobile cutting unit  71  and a fixed cutting unit (not shown). The mobile cutting unit  71  is fitted to a connective unit  73 , which is fixed down by a yoke-shaped flat piece  74  and two screws  75 . The connective unit  73  is connected with a reciprocating unit  76  and a magnet  761  (with the N-pole pointing in one direction and the S-pole pointing in the opposite direction) is provided on a lower portion of the reciprocating unit  76 . In use, after a motor  77  is turned on, an electromagnet  771  is magnetized and thus the reciprocating unit  76  may move laterally in a reciprocating manner due to the interaction between the magnet  761  and the electromagnet  771 . When the motor  77  is turned off, two springs  78  pushes the reciprocating unit  76  back to its original central position. 
         [0005]    Because the reciprocating unit  76  is disposed completely outside of the motor  77 , the size of the electric hair cutter  70  has to depend on the length of the reciprocating unit  76 . This factor makes it difficult to reduce the size of the electric hair cutter  70  and thus renders the hair cutter  70  inconvenient to carry. 
       SUMMARY OF THE INVENTION 
       [0006]    To eliminate the disadvantages of electric hair cutters in the prior art, the inventor has put in a lot of effort in the subject and has successfully come up with the reciprocating device of the present invention. 
         [0007]    The reciprocating device of the present invention comprises a housing, a magnetism transmitting unit, a coil unit, a reciprocating unit, a pivotal unit and a stationary magnet unit. After the coil unit is fitted to the magnetism transmitting unit, the former is partially surrounded by the latter, which is disposed inside the housing. In use, the reciprocating unit is magnetized by the coil unit and the magnetism transmitting unit and may move laterally in a reciprocating manner due to its interaction with two magnets of the stationary magnet unit, which is disposed next to and faces the coil unit. Because the reciprocating unit passes through the magnetism transmitting unit and only a part of the former is outside of the latter, the size of an electric hair cutter may be substantially reduced. 
         [0008]    The front end of the reciprocating unit passes through the magnetism transmitting unit and sticks out of the stationary magnet unit. The rear end of the reciprocating unit is pivotally fitted to the magnetism transmitting unit through the pivotal unit. In this manner, its front end is free to move laterally in a reciprocating manner outside of the stationary magnet unit. In a second embodiment, the pivotal point of the reciprocating unit is located near the midpoint of the reciprocating unit. In other words, the reciprocating unit is pivotally fitted to the magnetism transmitting unit near its midpoint. Its rear end passes through the magnetism transmitting unit and then the stationary magnet unit. Its front end sticks out of the magnetism transmitting unit. In this manner, its front end is free to move laterally in a reciprocating manner outside of the magnetism transmitting unit. 
         [0009]    Two or four springs may be provided between the stationary magnet unit and the housing. After the electric hair cutter is turned on, these springs continue to push the reciprocating unit back to the central position. After the electric hair cutter is turned off, these springs keep the reciprocating unit at the central position. 
         [0010]    In contrast to the reciprocating device of the electric hair cutter in the prior art, the reciprocating device of the present invention has at least the following two advantages:
       (1) In the reciprocating device of the present invention, a portion of the reciprocating unit is housed or enclosed in the magnetism transmitting unit, allowing a reduction in the size compared to the prior art design and hence the electric hair cutter in the prior art.   (2) In use, the front end of the reciprocating unit is free to move laterally in a reciprocating manner outside of the stationary magnet unit (as in the first embodiment) or the magnetism transmitting unit (as in the second embodiment). Also, in use, this front end is connected with a cutter.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a top view of an electric hair cutter in the prior art. 
           [0014]      FIG. 2  is a perspective view of a first embodiment of the reciprocating device of the present invention in an assembled condition. 
           [0015]      FIG. 3  is an exploded view of the first embodiment. 
           [0016]      FIG. 4  is an exploded view of a second embodiment of the reciprocating device of the present invention. 
           [0017]      FIG. 5  is a perspective view of the second embodiment of the reciprocating device of the present invention in an assembled condition. 
           [0018]      FIG. 6  is a top view showing the reciprocating motion of the second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    The purposes and advantages of the reciprocating device of the present invention will become more apparent and understandable when the following description is read in view of the accompanying drawings. Although two preferred embodiments of the present invention will be described in detail in the following, it should be understood that these preferred embodiments are to be regarded in an illustrative manner rather than a restrictive manner. 
       First Embodiment 
       [0020]    First, please see  FIGS. 2 and 3 . The reciprocating device of the present invention comprises a housing  1 , a magnetism transmitting unit  2 , a coil unit  3 , a reciprocating unit  4 , a pivotal unit  5  and a stationary magnet unit  6 . The magnetism transmitting unit  2  is disposed inside the housing  1 . The coil unit  3  may be fitted to the magnetism transmitting unit  2 . The front end of the reciprocating unit  4  passes through a middle portion of the magnetism transmitting unit  2 . The pivotal unit  5  passes through the housing  1 , the magnetism transmitting unit  2  and the reciprocating unit  4  and is thus fitted to the magnetism transmitting unit  2  near the rear end of the magnetism transmitting unit  2 . The stationary magnet unit  6  is disposed near the front end of the housing  1 . The front end of the reciprocating unit  4  passes through the stationary magnet unit  6 . In use, after the reciprocating device is powered up, the reciprocating unit  4  is magnetized by the coil unit  3  and the magnetism transmitting unit  2  and may move laterally in a reciprocating manner due to its interaction with the two (or two sets of) magnets  64 . 
         [0021]    The housing  1  comprises a first casing unit  10  and a second casing unit  12 . The first casing unit  10  comprises a lateral piece  100  and two wall pieces  101 . The lateral piece  100  connects the two wall pieces  101  at the rear side. A first hole  1000  is centrally provided in the lateral piece  100 . A first protruding member  1010  is disposed on the front end of each wall piece  101 . A first engagement design  1011  is provided in each wall piece  101  (between the corresponding protruding member  1010  and the lateral piece  100 ). The second casing unit  12  has a U shape with two walls and is connected with the front end of the first casing unit  10 . A hole  120  and a second engagement design  121  are provided in each of the two walls of the second casing unit  12 . Each hole  120  is engaged with the corresponding protruding member  1010  and each second engagement design  121  is engaged with the corresponding first engagement design  1011 , so that the second casing unit  12  is fitted to the first casing unit  10 . 
         [0022]    The magnetism transmitting unit  2  may be made of silicon steel, but not limited thereto. A vertical through hole  20  is provided near the rear end of the magnetism transmitting unit  2  and a first horizontal through hole  21  is horizontally formed near the rear end of the magnetism transmitting unit  2 . The magnetism transmitting unit  2  has three elongated legs  22  and has an “E” shape if viewed from the top. Slots  220  are formed in between these three legs  22  and are in communication with the first horizontal through hole  21 . 
         [0023]    The coil unit  3  comprises a core portion  30  and a coil portion  32 . A through central bore  300  is provided in the core portion  30 , so that the coil unit  3  may be fitted to the magnetism transmitting unit  2  when the central leg  22  of the magnetism transmitting unit  2  engages with the through central bore  300 . The coil portion  32  wraps around the core portion  30 . When current is fed to and through the coil unit  3 , a north pole and a south pole will be generated on the two longitudinal ends of the coil unit  3 . 
         [0024]    The reciprocating unit  4  has a cross shape. The front end of the reciprocating unit  4  passes through the first horizontal through hole  21 , the slots  220  and the through central bore  300 . A second through hole  40  is provided near the rear end of the reciprocating unit  4 . The pivotal unit  5  comprises a pivotal portion  50  and at least one bearing  52 . The at least one bearing  52  is disposed inside the vertical through hole  20 . The pivotal portion  50  is cylindrical and passes through the at least one bearing  52 , then passes through the second through hole  40 . Therefore, the two ends of the pivotal portion  50  stick out of the vertical through hole  20 . Whence, the reciprocating unit  4  may move laterally and pivotally inside the magnetism transmitting unit  2 . The pivotal unit  5  further includes two C-shaped rings  54 . A slot  501  is provided near each end of the pivotal portion  50 . After the two C-shaped rings  54  are fitted to the slots  501 , the pivotal portion  50  may be retained inside the vertical through hole  20 . 
         [0025]    The stationary magnet unit  6  comprises a seat unit  60 , two magnet retaining members  62 , a plurality of magnets  64  and a plurality of springs  66 . The seat unit  60  is disposed between the two protruding members  1010  of the first casing unit  10 . A central member  601  is formed at the front end of the seat unit  60 . A protruding member  61  is formed on the rear side of the seat unit  60 . An opening  610  is centrally provided in the protruding member  61 . The front end of the reciprocating unit  4  passes through the through central bore  300  of the coil unit  3  and the opening  610  to stick out of the seat unit  60 . The two magnet retaining members  62  are disposed on the protruding member  61  of the seat unit  60  and two (or two sets of) magnets  64  are disposed on each of the two magnet retaining members  62 . A second protruding member  6010  is formed on each of two sides of the central member  601 . Each spring  66  is held between either of the first protruding members  1010  and the corresponding second protruding member  6010 . 
         [0026]    Because the two first protruding members  1010  and the two second protruding members  6010  protrudes outwards, each spring  66  may be held in between either of the first protruding members  1010  and the corresponding second protruding member  6010  and hence would not be displaced when the reciprocating unit  4  moves laterally. 
         [0027]    In use, the reciprocating unit  4  is magnetized by the coil unit  3  and the magnetism transmitting unit  2  and may move laterally in a reciprocating manner due to its interaction with the magnets  64 . Also, the magnetromotive force would increase and the reciprocating unit  4  would move more quickly if the number of windings of the coil portion  32  increases or if more current is fed. Moreover, the frequency of such lateral motion may be adjusted by adjusting the magnitude of the input currency. With a cutting unit connected to the reciprocating unit  4 , an electric hair cutter may be formed for cutting hair. 
       Second Embodiment  
       [0028]    A second embodiment of the present invention is illustrated in  FIGS. 4 to 6 . The second embodiment is similar to the first embodiment, which has been previously described. The second embodiment and the differences between the first and second embodiments will be elaborated in the following. In the second embodiment, a housing  1  comprises a base piece  11 , two spring retaining pieces  13  and two connective pieces  15 . Each spring retaining piece  13  extends from the base piece  11  towards the front end of the housing  1 . Two first protruding members  130  are formed on the front side of each spring retaining piece  13 . Similarly, a second protruding member  6010  is formed on each side of the central member  601 . Because the two first protruding members  130  and the two second protruding members  6010  protrude outwards, each spring  66  may be held in between either of the first protruding member  130  and the corresponding second protruding member  6010  and hence would not be displaced when the reciprocating unit  4  moves laterally. 
         [0029]    Each of the two connective pieces  15  extends from the base piece  11  towards the front end of the housing  1 . Two first connective holes  150  are provided in each of the two connective pieces  15 . Four second connective holes  23  are provided on the magnetism transmitting unit  2 . Therefore, screws or rivets may be used to fixedly attach the magnetism transmitting unit  2  to the housing  1  through these connective holes  150  and  23 . 
         [0030]    The coil unit  3  comprises a core portion  30  and a coil portion  32 . A through central bore  300  is provided in the core portion  30 , so that the coil unit  3  may be fitted to the magnetism transmitting unit  2  when the central leg  22  engages with the through central bore  300 . An opening  302  is formed on either end of the through central bore  300 . The coil portion  32  wraps around the core portion  30 . When current is fed to and through the coil unit  3 , a north pole and a south pole will be generated on the two sides of the coil unit  3 . The reciprocating unit  4  has a cross shape. The front end of the reciprocating unit  4  passes through the first horizontal through hole  21 , the slots  220  and the opening  302  to reach the protruding member  61 . A second through hole  40  is provided near the midpoint of the reciprocating unit  4 . The front end of the reciprocating unit  4  sticks out of the magnetism transmitting unit  2 . 
         [0031]    In use, the reciprocating unit  4  is magnetized by the coil unit  3  and the magnetism transmitting unit  2  and may move laterally in a reciprocating manner due to its interaction with the magnets  64 . 
         [0032]    In the first embodiment, two springs  66  are used; the pivotal unit  5  passes through the second through hole  40  formed near the rear end of the reciprocating unit  4 ; the housing  1  comprises a first casing unit  10  and a second casing unit  12 ; the front end of the reciprocating unit  4  sticks out of the central member  601 ; the reciprocating unit  4  may move in a reciprocating manner laterally. In the second embodiment, four springs  66  are used; the pivotal unit  5  passes through the second through hole  40  formed near the midpoint of the reciprocating unit  4 ; the housing  1  comprises a base piece  11 , two spring retaining pieces  13  and two connective pieces  15 ; the front end of the reciprocating unit  4  sticks out of the magnetism transmitting unit  2 ; the reciprocating unit  4  may move in a reciprocating manner laterally. In these two embodiments, the pivotal point is located either at the rear end or near the midpoint of the reciprocating unit  4 ; in either embodiment, a portion of the reciprocating unit  4  is housed or enclosed in the magnetism transmitting unit  2 , allowing a substantial reduction of the size of the reciprocating unit and hence solving the oversize problem of the reciprocating unit encountered in the prior art. 
         [0033]    Although two preferred embodiments of the present invention have been described in detail hereinabove, it should be understood that the preferred embodiments are to be regarded in an illustrative manner rather than a restrictive manner, and all variations and modifications of the basic inventive concepts herein taught still fall within the scope of the present invention. 
         [0034]    Many changes and modifications in the above described embodiments of the invention can, of course, be carried out without departing from the scope thereof Accordingly, the invention is intended to be limited only by the scope of the appended claims.