Security gate

A gate unit comprising

• an extensible gate adapted to be extended or retracted to block openings of various widths, the extensible gate includes a main panel and a slidable extension panel supported for lateral sliding movement relative to the main panel to vary the width of the extensible gate, each of the main and extension panels including a top rail, a bottom rail arranged to lie below and in spaced-apart relation to the top rail, and several spindles arranged to interconnect the top and bottom rails and lie in spaced-apart relation to one another to form a spindle gap between each pair of adjacent spindles, and
• a panel-motion blocker including a spindle-motion limiter arranged to extend through a first spindle gap formed in the main panel and a second spindle gap formed in the extension panel and aligned to lie in side-by-side relation to the first spindle gap formed in the main panel and limiter-support means coupled to one of the top rails of the main and extension panels and the bottom rails of the main and extension panels for supporting the spindle-motion limiter in the first and second spindle gaps to engage spindles of the main and extension panels defining those first and second spindle gaps during attempted lateral sliding movement of the extension panel relative to the main panel so that such lateral sliding movement is blocked to provide the extensible gate with a selected width.