A rotary latch mechanism is provided for securing the lid of a container in a closed position wherein a mechanical advantage is employed to facilitate latching and unlatching of a latch plate of the rotary latch mechanism.
1. A latch mechanism, comprising:
a latch body having a first surface and an opposed second surface;
a first spring-biased shaft extending from said second surface of said latch body;
a latch plate formed with a notch which is adapted to capture a pin when in a latched position and to release the pin when in an unlatched position, said latch plate being formed with at least one gear tooth, said latch plate being mounted to said first spring-biased shaft which is effective to urge said latch plate toward said unlatched position;
a second spring-biased shaft extending from said second surface of said latch body and being spaced from said first spring-biased shaft;
an actuator formed with a first end, a second end, a side edge extending between said first and second ends and a locking pawl located opposite said side edge, said actuator being mounted to said second spring-biased shaft at a location between said first and second ends thereof, said second spring-biased shaft being effective to urge said actuator to a first position wherein said locking pawl engages said at least one gear tooth of said latch plate to retain said latch plate in said latched position;
a pin pivotally mounted to said latch body;
a pivot arm fixed to and pivotal with said pin, said pivot arm extending outwardly from said pin into engagement with said side edge of said actuator at a location between said second spring-biased shaft and said second end of said actuator, said pivot arm being oriented substantially perpendicularly to said side edge of said actuator;
a handle having a first end and a second end spaced from said first end, said second end of said handle being fixed to said pin, said first end of said handle being pulled outwardly in a direction away from said first surface of said latch body to initiate movement of said latch plate to said unlatched position, said outward movement of said first end of said handle causing said pin to rotate so that said pivot arm pivots said actuator about said second spring-biased shaft, said pivot arm being operative to overcome the spring force exerted by said second spring-biased shaft and to urge said actuator to a second position wherein said locking pawl disengages said at least one gear tooth allowing said latch plate to move to said unlatched position in response to the spring force applied thereto by said first spring-biased shaft.
2. The latch mechanism of claim 1 further including a key cylinder having an inner end and an outer end connected to said first end of said handle, said key cylinder extending through said latch body between spaced posts, said inner end of said key cylinder mounting a locking plate, said key cylinder being movable to a locked position wherein said locking plate engages said posts, said key cylinder being movable to an unlocked position wherein said locking plate disengages said posts to permit movement of said handle outwardly in a direction away from said first surface of said latch body.
3. The latch mechanism of claim 1 in which said space between said first and second ends of said handle provides a mechanical advantage in the course of movement of said handle outwardly from said first surface of said latch body thereby reducing the force required to rotate said pin and said pivot arm.