Multistage adjustable device for trunk bracket
BACKGROUND OF THE INVENTION 
     The invention relates to a trunk bracket. More particularly, the invention relates to a multistage adjustable device for a trunk bracket. 
     A conventional trunk has a tractile bracket at the back of the trunk. The tractile bracket has an inner sleeve and an outer sleeve. Two positioning bolts screw the inner sleeve and the outer sleeve tightly. However, a user has to loosen the bolts in order to adjust the tractile bracket. Further, the inner sleeve and the outer sleeve are easily deformed after a long period of usage. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a multi-step adjustable device for a trunk bracket so that the bracket can be protruded or retracted arbitrarily. 
     Accordingly, a multistage adjustable device for trunk bracket has a fixed handle, a driving handle, a pair of inner sleeves, a pair of drawbars, a pair of brakes, a pair of seats, a pair of checking bodies, a pair of outer sleeves and a pair of positioning plates. The fixed handle has two ends extending downwardly. Each of the two sockets is disposed in the corresponding ends of the fixed handle, respectively. The front end of the inner sleeve is inserted in the socket. A slot is formed on the socket and a corresponding slot is formed on the front end of the inner sleeve. Two recess holes are formed in the two end portions of the fixed handle, respectively. A compressed spring is inserted into the recess hole. Each end of the driving handle has a fin extending transversely therein. A hole is formed at the center of the fin to be hooked by a hook which is disposed at the upper end of the drawbar. Two cylindrical posts are protruded upwardly on the two corresponding end portions of the driving handle. The posts are inserted in the corresponding recess holes, respectively. A hollow inner sleeve is connected to the socket at the end of the fixed handle. The lower end of the drawbar is inserted in a shaft sleeve of the brake. The brake has a stop portion and a shaft sleeve extending upwardly from the stop portion. The stop portion and the checking body block each other. The seat has a movable portion with a transverse hole therein and an inserting portion extending upwardly from the movable portion. A longitudinal recess is formed on the inserting portion. A checking body has a truncated cone shaped cap and a positioning rod extending from the cap. A compressing spring and the positioning rod are inserted into the transverse hole. The hollow outer sleeve has two inner plates to separate the interior of the outer sleeve into two compartments. The first compartment of the outer sleeve receives a positioning plate which has a plurality of positioning holes to receive the positioning rod. The second compartment receives the seat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partly perspective exploded view of a preferred embodiment in accordance with the invention; 
     FIG. 2 is a partly cross-sectional view illustrating that a checking body is free from positioning holes; and 
     FIG. 3 is a partly cross-sectional view illustrating that a checking body is positioned by a positioning hole. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a multistage adjustable device for trunk bracket has a fixed handle 10, a driving handle 20, a pair of inner sleeves 30, a pair of drawbars 40, a pair of brakes 50, a pair of seats 60, a pair of checking bodies 70, a pair of outer sleeves 80 and a pair of positioning plates 90. 
     The fixed handle 10 has two terminal ends extending downwardly. Each of the two sockets 11 is disposed in the corresponding terminal ends of the fixed handle 10, respectively. The front end of the inner sleeve 30 is inserted in the socket 11. A slot 12 is formed on the socket 11 and a corresponding slot 31 is formed on the front end of the inner sleeve 30 in order to be inserted by a fin 21 extending from the end of the driving handle 20. Two recess holes 13 are formed in the two end portions of the fixed handle 10, respectively. A compressed spring 14 is inserted into the recess hole 13. 
     Each end of the driving handle 20 has a fin 21 extending transversely therein. A hole 22 is formed at the center of the fin 21 to be hooked by a hook 41 which is disposed at the upper end of the drawbar 40. Two cylindrical posts 23 are protruded upwardly on the two corresponding end portions of the driving handle 20. The posts 23 are inserted in the corresponding recess holes 13, respectively. 
     The hollow inner sleeve 30 is connected to the socket 11 at the end of the fixed handle 10. 
     The lower end of the drawbar 40 is inserted in a shaft sleeve 51 of the brake 50. 
     The brake 50 has a stop portion 52 with an inclination 53 and a shaft sleeve 51 extending upwardly from the stop portion 52. The stop portion 52 and the checking body 70 block each other. 
     The seat 60 has a movable portion 62 with a transverse hole 64 therein and an inserting portion 61 extending upwardly from the movable portion 62. A longitudinal recess 63 is formed on the inserting portion 61. 
     A checking body 70 has a truncated cone shaped cap 72 with an inclination 73 thereon and a positioning rod 71 extending from the cap 72. A compressing spring 65 and the positioning rod 71 are inserted into the transverse hole 64. 
     The hollow outer sleeve 80 has two inner plates 81 to separate the interior of the outer sleeve 80 into two compartments. The first compartment of the outer sleeve 80 receives a positioning plate 90 which has a plurality of positioning holes 91 to receive the positioning rod 71. The second compartment receives the seat 60. 
     FIG. 2 illustrates that a checking body 70 is free from the positioning holes 91. The driving handle 20 is pressed upwardly to move the drawbars 40 and the corresponding brakes 50 upwardly. The brakes 50 disengage from the corresponding checking bodies 70. Each of the compressing springs 65 rebound to force each of the corresponding positioning rods 71 disengaging from each of the corresponding positioning holes 91. FIG. 3 illustrates that a checking body 70 is positioned by a positioning hole 91. The driving handle 20 is released. The springs 14 force the driving handle 20, the corresponding drawbars 40 and the corresponding brakes 50 to move downwardly. The brakes 50 block the corresponding checking bodies 70 and force the corresponding checking bodies 70 to move toward the corresponding positioning holes 91. Each of the positioning rods 71 is inserted in each of the corresponding positioning holes 91. 
     The invention is not limited to the above embodiment but various modification thereof may be made. It will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention.