Quick-release holding down device for bicycle
BACKGROUND AND SUMMARY OF THE INVENTION 
     FIGS. 1 and 2 show a quick-release holding down device used in a bicycle for holding a part of the bicycle in place. The quick-release holding down device comprises a lever, a bolt, a screw rod, a notched block, a packing plate, a spring, and a nut. The lever has a front opening. The bolt has a screw hole and is secured to the lever and disposed inside the front opening. The screw rod has one end inserted through the front opening of the lever and threaded into the screw hole on the bolt, and an opposite end inserted through the notched block, the packing plate, the spring, and the device to be held down, and then threaded into The screw hole on the nut. The screw bolt can be driven into or out of the screw hole on the nut by the lever. When installed, the lever is turned about the bolt and stopped against a notch on the notched block. This structure of a quick-release holding down device is still not satisfactory in function, because the lever may be turned by error to loosen the screw rod from the nut, causing the device being held down to disconnect from position. 
     The present invention has been accomplished to provide a quick-release holding down device which eliminates the aforesaid problem. According to the preferred embodiment of the present invention, the quick-release holding down device comprises a headed screw rod, which is inserted through the device to be held down and then screwed up with a nut, a lever is turned about a pivot on the head of the headed screw rod, and a headed lock bar controlled by a combination lock provided in the lever for preventing the lever from turning about the pivot when the numbers in the lock are incorrect. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a quick-release holding down device according to the prior art. 
     FIG. 2 is an elevational view of the quick-release holding down device of FIG. 1. 
     FIG. 3 is an exploded view of a quick-release holding down device according to the present invention. 
     FIG. 4 is an elevational view of the quick-release holding down device of FIG. 3. 
     FIG. 5 is a sectional view taken along line 5--5 of FIG. 4. 
     FIG. 6 shows the moving direction of the lever of the quick-release holding down device of FIG. 5. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 3 through 6, the invention includes a holding down device, comprises a lever 20, a spring 21, a headed lock bar 22, a screw rod 23, and a plurality of wheel and locking plate sets 24, 24&#39;, and 24&#34;. 
     The lever 20 comprises a plurality of chambers 201, 201&#39;, and 201&#34; spaced in the longitudinal direction, which receive the wheel and locking plate sets 24, 24&#39;, and 24&#34; respectively, a longitudinal hole 202 extended through the chambers 201, 201&#39;, and 201&#34;, two eyed lugs 2031 and 2032 at one end, and an opening 203 defined between the eyed lugs 2031 and 2032 that communicates the longitudinal hole 202. 
     A spring 21 is mounted around the headed lock bar 22 and received inside the longitudinal hole 202. The spring 21 has one end abutting a stepped inside wall of the longitudinal hole 202 and an opposite end abutting the head of the headed lock bar 22 for providing an outward force or bias to the head of the headed lock bar 22. 
     The headed lock bar 22 is inserted through the spring 21 into the longitudinal hole 202 of the lever 20. The headed lock bar 22 has a plurality of projecting blocks 220, 220&#39;, and 220&#34; spaced in the longitudinal direction. 
     The screw rod 23 has a locating block 231 secured at one end thereof. The locating block 231 of the screw rod 23 has a pivot hole 2311 pivotably connected between the two eyed lugs 2031 and 2032 of the lever 20 by a pivot 24 passing therethrough, and a side notch 2310, which receives the head of the headed lock bar 22. 
     The wheel and lock plate sets 24, 24&#39;, and 24&#34; are comprised of number wheels 240, 240&#39;, and 240&#34;, and washers 241, 241&#39;, and 241&#34;, respectively mounted around the headed lock bolt 22 and received in the chambers 201, 201&#39; and 201&#34;, each having a respective notch 2401, 2401&#39;, or 2401&#39;. When the notches 2401, 2401&#39;, and 2401&#34; are aligned, the headed lock bar 22 can be moved longitudinally relative to the number wheels 240, 240&#39;, and 240&#34;. If the notches 2401, 2401&#39;, and 2401&#34; are not aligned, the projecting blocks 220, 220&#39;, and 220&#34; are respectively stopped by the number wheels 240, 240&#39;, and 240&#34;, and the lever 20 is stopped by the lock bar 22 from turning about the pivot 24. 
     When in use, the screw rod 23 is inserted in proper order through a cup 25, a left-side spring 26, the device to be held down, and a right-side spring 27, and then threaded into a nut 28. By means of turning the number wheels 240, 240&#39;, and 240&#34; to align the notches 2401, 2401&#39;, and 2401&#34;, the lever 20 can be unlocked from the headed lock bar 22.