| 摘要 |
<p>A dual-purpose extension ladder comprises a rotary device (3) and a locating device, in which, the rotary device (3) is placed on the top of a left ladder (1) and a right ladder (2) and composed of a left ladder rotary table (31) and a right ladder rotary table (32) which are coaxial with each other and connected with the top ends of the left ladder and the right ladder respectively, the inside surfaces of the left and right rotary table (31,32) perpendicular to a rotary shaft (33) are conjoint with each other; and the locating device includes a first key groove (8) and a second key groove (81) arranged on the head end of the left ladder rotary table at intervals with the same geometry and dimensions, a locating key (6) having a spring (7) is provided on the upper portion of the right ladder rotary table (32) at a position relative to the key grooves, and a lever (5) is set at the upper portion of the right ladder rotary table (32) with one end being in contact with the locating key (6) and the other end connecting with an operating link (4).</p> |
