A combination lock comprising:
- a lock body having a hollow spindle longitudinally protruding outwardly from a lock base of said lock body and a tensioning spring held in a spring socket formed in said lock base;
- a locking bolt having a longitudinal bolt protruding inwardly towards said lock base from a bolt base of said locking bolt slidably engageable with a central bolt hole formed in said hollow spindle, and a plurality of projections longitudinally formed and equally spaced on said longitudinal bolt slidably engageable with a longitudinal notch formed in said spindle;
- a plurality of dials rotatably mounted on said lock body each said dial having a plurality of numerals circumferentially formed on an outer cylindrical surface of the dial, and an inner ring formed inside the dial having a plurality of recesses annularly formed in the inner ring of the dial;
- a plurality of sleeves rotatably mounted on said hollow spindle each said sleeve having a plurality of protrusions formed on an outer cylindrical surface of said sleeve engageable with said recesses formed in said inner ring of said dial, an opening slot formed through an inner ring of said sleeve for operatively slidably engageable with said projections of said bolt for opening said lock, a plurality of dial-sensing recesses annularly formed in the inner ring of said sleeve rotatably projectively corresponding to each said numeral formed on said dial, and a plurality of annular corrugated teeth annularly formed on the inner ring of said sleeve normally retarding said projections for locking said bolt;
- a plurality of spacers slidably held on said spindle for partitioning every two neighbouring said sleeves, of which one inner spacer is urged by said tensioning spring to resiliently urge said sleeves to be engageable with said dials;
- a plurality of sensing positioner plates slidably held on said spindle each said positioner plate inserted between each said sleeve and each said spacer having a plurality of sensing protrusions annularly formed on said positioner plate resiliently clickingly engageable with each said dial-sensing recess corresponding to each said numeral of said dial;
- and
- a combination-changing plate having two extending keys formed on two opposite side portions thereof normally embedded in two key holes formed in said bolt base, and operatively inverted to push said sleeves inwardly to be disengaged from said dials for freely rotating said dials for resetting a new combination;
- whereby upon a rotation of said dial and said sleeve, each said sensing protrusion of said sensing positioner plate will be rotatably clickingly engageable with each said dial-sensing recess of said sleeve for subsequently sensing the dialing operation from each numeral to the next numeral by feeling;
- and upon a trial opening by a thief by rotating the dials, the sleeves and withdrawing the bolt, each said projection of said locking bolt will be rotatably retarded by the corrugated teeth annularly formed in said sleeve, thereby confusing the opening trial by sense of feeling.