Abstract:
The present invention relates a wheel assembly of a luggage, which has two wheels side by side and the control assembly. The control assembly has a switch device for manipulation to brake the wheels. The control assembly has a fixed position to be manipulative by user easily. The wheels have small widths that makes the luggage may run on a carpet without having to draw the luggage with great strength.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a luggage and, more particularly, to a wheel assembly of a luggage. 
     2. Description of the Related Art 
     For a modern design of a luggage, it concerns a fancy look and strong structure, furthermore, a convenient operation is an important issue. In drawing the luggage, wheels on a bottom of the luggage should be free for rolling, but not every roads that the luggage may run smoothly thereon. For example, the luggage may run freely on a rock flood of, such as, airport or hotel. But it is a hard work when user draws the luggage across a carpet. 
     In addition, the conventional luggage doesn&#39;t have any brake function that the luggage may be moved unexpectedly. We found some luggages, have brakes, but it is not convenient to operate it. As shown in  FIG. 1 , such luggage is provided with a control device  2  to be manipulated for braking the wheel  1 . The control device  2  turns along with the wheel  1  that for some angles, such as the control device  2  is turned to under the case, user is hard to operate it. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a wheel assembly of a luggage, which may run on almost every kind of roads. 
     The secondary objective of the present invention is to provide a wheel assembly of a luggage, which has brake function, and is easy to operate it. 
     To achieve the objective of the present invention, a wheel assembly of a luggage, which is mounted on an object, includes a wheel base, which is pivoted on the object along a vertical direction, having a through bore along the vertical direction and a transverse axial bore through opposite sides of the wheel base and deviating the vertical direction; a left wheel, which is pivoted on the wheel base, having a concave portion on a side, in which an inner annular wall having a plurality of slots is formed; a right wheel, which is pivoted on the wheel base beside the left wheel, having a concave portion, in which an inner annular wall having a plurality of slots is formed, on a side facing the side of the left wheel having the concave portion; an axle inserted through the axial bore of the wheel base and connecting the left wheel and the right wheel respectively; and a control assembly, which includes a switch device pivotally arranged above the wheel base, an axial shaft inserted through the through bore of the wheel base and moved by the switch device for a movement along the vertical direction, and a brake device having an end connected to a bottom end of the axial shaft and an opposite end with a transverse stop piece having opposite ends engaged with the slots of the left wheel and the right wheel when the axial shaft is moved upwards. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the conventional wheel assembly of the luggage with brake function; 
         FIG. 2  to  FIG. 4  are various views of the wheel assembly of a preferred embodiment of the present invention mounted on the luggage; 
         FIG. 5 ,  FIG. 5A , and  FIG. 5B  are exploded views of the preferred embodiment of the present invention; 
         FIG. 6  is a sectional view of the preferred embodiment of the present invention, showing the wheel braked; 
         FIG. 7  is another sectional view of the preferred embodiment of the present invention, showing the wheel being braked; 
         FIG. 8  is a sectional view of the preferred embodiment of the present invention, showing the wheel being unbraked. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 2-4  show a luggage  100  including two case pieces  10 ,  20  and four wheel assemblies, two of which  30  are mounted on a bottom of the case piece  10 , and the other two of which  40  are mounted on a bottom of the case piece  20 . The wheel assemblies  40  are equipped with brakes, and the other two are not. The following description is about the wheel assembly  40  with brake. 
     As shown in  FIG. 5 ,  FIG. 5A ,  FIG. 5B ,  FIG. 6 , and  FIG. 7 , the wheel assembly  40  includes a seat member  42 , a pivot base  44 , a wheel base  46 , a ball disk  47 , a shaft sleeve  48 , a pad  49 , a left wheel  50 , a right wheel  52 , an axle  54 , a control assembly  56 , and an auxiliary positioning assembly  64 . 
     The seat member  42 , which is fixed at a corner of the bottom of the case piece  20 , has a bottom bore  421  and a lateral opening  422 . 
     The pivot base  44 , which is received in the seat member  42 , has a round bore  441  aligned to the bottom bore  421 , and two lateral plates  442 , each of which has a positioning bore  443 . 
     The wheel base  46  has a vertical through bore  461 . The shaft  44  is inserted into the through bore  461  of the wheel base  46 , the ball disk  47 , the bottom bore  421  of the seat base  42 , and the round bore  441  of the pivot base  44  in sequence. And then, the shaft  44  is inserted into the pad  49  to pivot the wheel base  46  on a bottom of the seat member  42 . The wheel  46  further has a transverse axial bore  462  and a lateral through bore  463  communicated with the through bore  461 . 
     The left wheel  50  is as same as the right wheel  52 . The left and right wheels  50 ,  52  are pivoted side by side on the wheel base  46 . The neighboring sides of the wheels  50 ,  52  have a concave portion, in which an inner annular wall having a plurality of slots is formed. The slots  521  are shown in  FIG. 5  for example. The wheels  50 ,  52  have a threaded bore  502 ,  522  at a center respectively and trenches  503 ,  523  on a circumference respectively. 
     The axle  54  is inserted into the axial bore  462  of the wheel base  46 , and has two threaded sections  541 ,  542  on opposite ends to be screwed with the threaded bores  502 ,  522  respectively that the wheels  50 ,  52  are pivoted on the wheel base  46 . Two lids  55  are provided on the wheels  50 ,  52  to shield the opposite ends of the axle  54 . 
     The control assembly  56  has a switch device  57 , a pin  58 , a brake device  59 , an axial shaft  60 , a top lid  62 , and a transverse shaft  63 . 
     The switch device  57  is provided between the lateral plates  442  of the pivot base  44 . The pin  58  is inserted into a pivot bore  574  of the switch device  57 . Opposite ends of the pin  58  are inserted into the positioning bores  443  of the lateral plates  442 . The switch device  57  has an operative board  571  through the lateral opening  422  of the seat member  42  and two parallel arms  572 . The operative board  571  is manipulative for movement up and down, and each of the arms  572  has a through bore  573 . 
     The brake device  59  has a through bore  591  at an end thereof, and a convex transverse stop piece  592  at the other end. 
     The axial shaft  60  is inserted through the through bore  591  of the brake device  59  and the shaft sleeve  48 . The axial shaft  60  has a head portion  601  at a bottom thereof, and a C ring  61  is fitted to the axial shaft adjacent to the head portion  601  to prevent the brake device  59  from loosing. As shown in  FIG. 6 , after assembling, the transverse stop piece  592  of the brake device  59  is between the axial bore  462  and the through bore  461 , and the axial shaft  60  has an annular slot  602  adjacent to the top end. 
     The top lid  62 , which is provided on the top end of the axial shaft  60 , has a transverse through bore  621  aligned to the annular slot  602 . The transverse shaft  63  passes through the through bores  573  of the arms  572  and through between the transverse through bore  621  of the top lid  62  and the annular slot  602  of the axial shaft  60 . 
     With the elements as described above, one may switch the switch device  57  up and down to move the axial shaft  60  along a vertical axial direction of the shaft sleeve  48 . As shown in  FIG. 6 , the upward-moved axial shaft  60  will move the brake device  59  to engage opposite ends of the lateral stop piece  592  with the slots  521  of the left and right wheels  50 ,  52  for brake. On the contrary, when one switches the control shaft downward, it may disengage the lateral stop piece  592  of the brake device  59  with the slots of the wheels, as shown in  FIG. 8 . As a result, the left and right wheels  50 ,  52  may run freely. 
     The auxiliary positioning assembly  64  is provided for restriction of the axial shaft  64  at an up position and a down position when it is moved by the switch device  57 . The auxiliary positioning assembly  64  includes: 
     a first hole  65  on a free end of each arm  572 ; 
     a second hole  66  on the pivot base  44 ; 
     a first T-shaped member  67  having a transverse shaft  671  inserted into the first hole  65 , and a post  672  having an axial bore  673 ; 
     a second T-shaped member  68  having a transverse shaft  681  inserted into the second hole  66 , and a post  682  inserted into the axial bore  673  of the post  672  of the first T-shaped member  67 ; and 
     a spring  69  fitted to the posts  672 ,  682  of the first and second T-shaped members  67 ,  68 . 
     The combination of the first and second T-shaped members  67 ,  68  restricts the spring  69  compressing along a linear direction. The elasticity of the spring  69  may keep the axial shaft  60  at the up or down positions that help the operation of brake. 
     Above is the description of the elements of the present invention, and the functions of the present invention are listed hereunder: 
     1. The wheel assembly  40  of the present invention includes two wheels, the left wheel  50  and the right wheel  52 . The widths of the wheels is smaller, and the wheels has the trenches  503 ,  523  that the luggage equipped with the wheel assemblies of the present invention still may be drawn on a carpet without having to exert a great power. 
     2. The switch device  57  is for manipulation of brake. It has a fixed position and will not turn along with the wheel base  46  that is convenient to operate it. 
     3. The transverse stop piece  592  of the brake device  59  is between the axial bore  462  and the through bore  461 , and is convex. In the braking condition of  FIG. 6 , when the luggage  100  is impacted by an unexpected force and forces the left wheel  50  and the right wheel  52  turning, it will make the brake device  59  deformed and engaging the transverse stop piece  592  with the slot immediately to brake the luggage. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.