An inventive stepladder of tripod structure with an actuating mechanism that extends the rear legs and front step assembly in a coordinated manner to assume the tripod footprint. The actuating mechanism may include a vertical center post; a sliding collar journaled on the center post to coordinate the extension and retraction of the rear legs and step assembly; an A-brace for extending and retracting the step assembly and further serving as an auxiliary work platform for the uppermost step in the step assembly; leg braces for extending and retracting the rear legs, and a stop block attached to the lower end of the center post. A locking pin may be provided to secure the position of the sliding collar along the center post. The stop block may function to relieve shear stress on the locking pin and to provide support for a user's weight on the A-brace.
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