Abstract:
A fixing unit that includes a sleeve assembly defining a through hole along an axis thereof, and an assembly slidably received in the through hole. The assembly includes first and second end. An elastic claw extends from the first end. The second end can be actuated by a user. The elastic claw is biased towards an open state. The fixing unit moves between a first and a second position. In the first position, the elastic claw is received in the sleeve assembly and contracts. In the second position the elastic claw extends out of the sleeve assembly and expands. 
     When the first end is pressed for the first time, the fixing unit is moved from the first position to the second position, and when the first end is pressed for the second time, the fixing unit is moved from the second position to the first position.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to fixing units. The invention particularly relates to a fixing unit for joining two objects. 
         [0003]    2. Description of Related Art 
         [0004]    Screws and rivets are commonly used to join two objects. In using screws, a hand tool such as a screwdriver is needed, which can be inconvenient. In using rivets, a special tool is required and the rivets are not reusable. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is an exploded, isometric view of a fixing unit in accordance with a first embodiment of the present invention, the fixing unit including a sleeve assembly; 
           [0006]      FIG. 2  is an exploded, isometric view of the sleeve assembly of  FIG. 1 ; 
           [0007]      FIGS. 3 to 5  are assembled, cross-sectional views of the fixing unit of  FIG. 1  and two objects, showing the fixing unit in different states; and 
           [0008]      FIG. 6  is an assembled, cross-sectional view of a fixing unit in accordance with a second embodiment of the present invention, together with two objects. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    Referring to  FIGS. 1 and 2 , a fixing unit for joining two objects  100 ,  200  (see  FIG. 3 ) each defining a mounting hole, is provided in accordance with an embodiment of the present invention. The fixing unit includes a sleeve assembly  10 , a first engaging member  20 , a second engaging member  30 , a splaying member  40 , an expandable member  50 , an operating member  60 , and two elastic members  70 ,  80 . 
         [0010]    The sleeve assembly  10  includes a first sleeve  12  and a second sleeve  14 . The first sleeve  12  defines a through hole  122  along its axis. A thread portion  124  is formed at a lower portion of an inner wall bounding the through hole  122  of the first sleeve  12 . A plurality of bar-shaped projections  126  axially extends from a middle portion of the inner wall of the first sleeve  12 , and is equably located on the inner wall. A blocking ring  128  extends from a circumference of the inner wall of the first sleeve  12  over the projections  126 . The second sleeve  14  defines a through hole  143  along its axis. A thread portion  144  is defined at an upper portion of an outer wall of the second sleeve  14 . A lower portion of the second sleeve  14  gradually shrinks down to form a taper portion  142 . A blocking ring  148  extends from a circumference of a middle portion of an inner wall bounding the through hole  143  of the second sleeve  14 . The first sleeve  12  and the second sleeve  14  are coupled together via engagement of the thread portions  124 , 144 . 
         [0011]    The first engaging member  20  includes an rounded base  23 , and a pushing pole  22  extending perpendicularly from a central portion of the rounded base  23 . A plurality of teeth  24  extends from and is disposed equably along a circumference of the base  23 . An engaging groove  26  is formed between every two adjacent teeth  24 . The first engaging member  20  defines a through hole  222  along its axis. 
         [0012]    The second engaging member  30  includes a pressing part  31 , and a sliding pole  32  extending from an end of the pressing part  31 . The pressing part  31  and the sliding pole  32  are columns along a same axis. The diameter of the pressing part  31  is greater than the diameter of the sliding pole  32 . A teeth part is set on an upper portion of the pressing part  31 . An assembly hole (not shown) is defined in a bottom of the pressing part  31 . The teeth part includes a plurality of toothed assemblies  34 . The toothed assemblies  34  extend from the pressing part  31  and are equably disposed along a circumference of the pressing part  31 . Each of the toothed assemblies  34  includes a first tooth  342  and a second tooth  344 , wherein the first tooth  342  and the second tooth  344  are connected end-to-end, and each includes a slanted driving surface  346  formed on the top thereof. An engaging groove  36  is formed between every two adjacent toothed assemblies  34 . 
         [0013]    The splaying member  40  includes a connecting shaft  42 , and an elastic claw  44  made up of a plurality of fingers extending from an end of the shaft  42 . The elastic claw  44  is expanded in its natural state. 
         [0014]    The expandable member  50  is cylinder-shaped with a through hole  52  defined therein. The expandable member  50  is made of flexible materials. 
         [0015]    The operating member  60  is discoid-shaped. An assembly hole (not shown) is defined in the bottom of the operating member  60 . 
         [0016]    The elastic members  70 ,  80  are coil springs. 
         [0017]    Referring also to  FIG. 3 , in assembly, a free end of the shaft  42  of the splaying member  40  is operated to go through the tip of the taper portion  142  and into the through hole  143  of the second sleeve  14 . Free ends of the fingers of the elastic claw  44  of the splaying member  40  just barely extend out of the tip of the taper portion  142 . The elastic member  70  is received in the through hole  143  of the second sleeve  14  and coiled round the shaft  42  of the splaying member  40 . The free end of the shaft  42  is mounted in the assembly hole in the bottom of the pressing part  31  of the second engaging member  30 . Two ends of the elastic member  70  prop up the bottom of the pressing part  31  and the blocking ring  148  of the second sleeve  14  respectively. The sliding pole  32  of the second engaging member  30  is slid into the through hole  222  of the first engaging member  20  from the bottom, and the base  23  of first engaging member  20  is supported on the top of the pressing part  31  of the second engaging member  30 . The first engaging member  20  together with the second engaging member  30  is received in the through hole  122  of the first sleeve  12 . The first sleeve  12  and the second sleeve  14  are coupled together, while an adjustment is done to make the projections  126  of the first sleeve  12  be respectively received in some of the engaging grooves  26  of the first engaging member  20  and the engaging grooves  36  of the second engaging member  30 . The elastic member  80  is received in the through hole  122  of the first sleeve  12  and coiled round the pushing pole  22  of the first engaging member  20 . The top end of the pushing pole  22  of the first engaging member  20  is mounted in the assembly hole of the operating member  60 . Two ends of the elastic member  80  prop up the operating member  60  and the blocking ring  128  of the first sleeve  12  respectively. The elastic member  80  urges the first engaging member  20  to rise a little, such that lower tips of the teeth  24  move to upper tips of the first teeth  342  and the second teeth  344  of the toothed assemblies  34  respectively; and the elastic claw  44  contracts as its retracted into the taper portion  142 . The expandable member  50  is fixed to the tip of the taper portion  142  of the second sleeve  14  by any known method (for example, by sticking), wherein the through hole  52  of the expandable member  50  aligns with the through hole  143  of the second sleeve  14 . 
         [0018]    Referring also to  FIGS. 4 and 5 , in use, engagements among only one tooth  24 , one toothed assembly  34 , and one projection  126  will be described as an example hereinafter. 
         [0019]    In using the fixing unit to join the objects  100 ,  200 , firstly, the expandable member  50  is operated to go through the mounting holes of the objects  100 ,  200 . Secondly, the operating member  60  together with the first engaging member  20  is pressed down. The second engaging member  30  is pushed by the first engaging member  20  to slide down along the projection  126  while the elastic members  70 ,  80  are compressed, and then rotated left after the top tip of the first tooth  342  passes over the lower end of the projection  126  because of the engagement between the lower tip of the tooth  24  and the slanted driving surface  346  of the first tooth  342 , such that the projection  126  is located on the slanted driving surface  346  of the first tooth  342 . The splaying member  40  is moved down. Thus, the elastic claw  44  extends out of the taper portion  142  of the second sleeve  14  and expands. The expandable member  50  is expanded by the expanded elastic claw  44 . Lastly, the operating member  60  is released. Thus, the elastic member  70  is restored and makes the second and first engaging member  30 ,  20  rise up. The slanted driving surface  346  of the first tooth  342  engages with the lower end of the projection  126  due to the force of the elastic member  80  to make the second engaging member  30  rotate further, until the projection  126  abuts against a left side of the second tooth  344  of the toothed assembly  34  and cannot move any more. Thus, because the projection  126  engages with the second engaging member  30  preventing vertical movement thereof, the claw  44  is locked in its current extended position. The two objects  100 ,  200  are sandwiched and joined by the expanded expandable member  50  and the taper portion  142  of the second sleeve  14 . 
         [0020]    To separate the objects  100 ,  200 , firstly, the operating member  60  is pressed down to drive the first engaging member  20  to slide down along the projection  126  accommodated in the engaging groove  26 . The second engaging member  30  is pushed by the first engaging member  20  to move down, and rotated left after the top tip of the second tooth  344  passes over the lower end of the projection  126  because of the engagement between the lower tip of the tooth  24  and the slanted driving surface  346  of the second tooth  344 . Secondly, the operating member  60  is released, such that the elastic member  70  is restored and makes the second and first engaging members  30 ,  20  to rise. The slanted driving surface  346  of the second tooth  344  engages with the lower end of the projection  126  due to the force of the elastic member  80 , to make the second engaging member  30  rotate further until the lower end of the projection  126  falls into another engaging groove  36  next to the right side of the second tooth  344  of the toothed assembly  34 . The elastic member  80  is restored and makes the first engaging member  20  move up along the projection  126 . The elastic member  80  is restored further to make the second engaging member  30  together with the splaying member  40  rise, with the projection  126  accommodating in the another engaging groove  36 . Thus, the claw  44  of the splaying member  40  contracts as its retracted back into the second sleeve  14  again, and the expandable member  50  restores to its natural state of contraction. The objects  100 ,  200  can be easily separated. 
         [0021]    Referring to  FIG. 6 , in another embodiment of the present invention, the expandable member  50  is omitted, and the claw  44  of the splaying member  40  is directly used to join the objects  100 ,  200 . 
         [0022]    Certain applications will require more or less retention force by the fixing member. The fixing force of the invention can be adjusted by varying the elasticity of the elastic claw  44 . This can be done by altering the size, shape and materials used for the claw  44 . 
         [0023]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and they will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.