Patent ID: 7140072

Claim:
A lockable ladder hinge comprising first and second hinge members coupled together for rotation about a common axis, a cam having a pair of tabs coupled to the second hinge member, the first hinge member having tab-receiving spaces, an actuator, means for coupling the actuator to the cam so that, when the actuator is moved in a first direction, the cam moves outwardly relative to the common axis to cause the pair of tabs to withdraw from the tab-receiving spaces to unlock the hinge members, and so that, when the actuator is moved in a second direction opposite to the first direction, the cam moves inwardly relative to the common axis to cause the pair of tabs to enter the tab-receiving spaces to lock the hinge members, the means for coupling the actuator to the cam includes a mounting member, an actuator connector link, and a cam link, the actuator connector link is coupled through the mounting member to the actuator to rotate in the first direction about the common axis for radial movement of the tabs away from the common axis to withdraw the tabs from the tab-receiving spaces to allow the second hinge member to pivot relative to the first hinge member and to rotate in the second direction about the common axis for radial movement of the tabs toward the common axis to move the tabs into the tab-receiving spaces to block the second hinge member from pivoting relative to the first hinge member, and wherein the first hinge member includes a first segment, a second segment, and a pair of guide rings, each of the first and second segments is formed to include at an end thereof an annular flange portion, the pair of guide rings are arranged in side-by-side relationship to one another and between the annular flange portions of the first and second segments, and the first and second segments are coupled together to form the first hinge member.