Key driven internal locking device for cabinet drawers

A cabinet comprising:

• a plurality of drawers each comprising two slides on outer surfaces of two sides respectively, and a latch disposed on an outer surface of a rear end and including an upper inclined surface, an upper projection in rear of the upper inclined surface, a lower inclined surface, an upper flat surface in front of the upper inclined surface, a lower flat surface in front of the lower inclined surface, and a shoulder between the lower inclined surface and the lower flat surface;
• and
• a key driven internal locking device comprising:
• a rod including a key hole on a front end, and a bent member adjacent to a rear end;
• a longitudinal member secured to an inner surface of a rear end of the cabinet and including a longitudinal groove;
• a sliding member slidably disposed in the longitudinal groove and including a plurality of rectangular openings on a front surface wherein a predetermined number of the rectangular openings correspond to the latches, a protrusion on a top of the sliding member, and an upper driven member secured to the front surface of the sliding member and having a through hole with the bent member passing through;
• a plurality of fastening plates each secured to two sides of the longitudinal member wherein an uppermost one of the fastening plates has a pivot hole with the rear end of the rod passing through into the longitudinal member;
• and
• a concave member fastened in an upper portion of the longitudinal member and above the protrusion;
• wherein in a locked state of the cabinet, the bent member projects upward, the protrusion is disposed in the concave member, each latch is inserted into the corresponding rectangular opening, each latch is blocked by an inner surface of the front surface of the sliding member, and all of the drawers are locked;
• wherein in response to inserting a key into the key hole and clockwise rotating the key, the rod clockwise rotates to push the driven member downward, the sliding member moves downward to clear the protrusion out of the concave member, the latches are not blocked by the inner surface of the front surface of the sliding member, and all of the drawers are unlocked;
• wherein in response to pulling out one drawer in one operation, the latch pushes the front surface of the sliding member upward to insert the protrusion into the concave member and the latches of the remaining drawers are blocked by the inner surface of the front surface of the sliding member, and the remaining drawers are locked;
• wherein in response to pulling out one drawer in one operation, the upper inclined surface of the latch pushes the front surface of the sliding member upward to insert the protrusion into the concave member and the shoulders of the latches of the remaining drawers are blocked by the inner surface of the front surface of the sliding member;
• and
• wherein in response to pulling out one drawer in one operation, all of the remaining drawers are locked and prior to pulling out a second drawer, one drawer is pushed in with the lower inclined surface of one drawer pushes down the sliding member so that the shoulders of the latches are not blocked by the inner surface of the front surface of the sliding member.