Sweet’s indexed catalogue of building construction for the year 1906 (1906)
New York : Chicago : Architectural Record · leaf 745
for automatically opening and closing the Meeker type of freight elevatordoors. It can be used for elevators of all speeds. The doors are operated by compressed air and con-trolled by the elevator operator through a foot treadle so located on the elevator platform that theoperator can open or close…
Building materials
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