GB643010A - Ladder control device - Google Patents

Abstract

643,010. Fire-escapes. COMMANDITAIRE VENNOOTSCHAP FABRIEK VOOR AUTO-EN MACHINEBOUW REINIGINGS-EN BRANDWEER-MATERIEEL, VOORHEEN J. GEESINK & ZONEN., and SCHIERECK, W. Oct. 7, 1946, No. 29879. [Class 47 (i)] In a hydraulically-operated fire ladder, means are provided to prevent excessive extension of the ladder at any elevation and excessive lowering thereof at any extension. In one form, a valve 17 operated by a hand lever 33 and provided with supply and exhaust ducts 21, 22 co-operates with a rotatable sleeve 18 coupled to the ladder whereby elevation and lowering are effected by the provision of passages 25, 26 and 29, 30 communicating with the ladder operating gear. A similar valve 19 operated by a hand lever 36 effects the extension and collapsing of the ladder. Movement of the levers 33, 36 is limited by abutment members 41, 44 movable therewith and co-operating with abutment members 43, 42 movable with the sleeves 20, 18 respectively. Pointers 34, 37 show the setting of the hand levers, and pointers 39, 40 the actual condition of the ladder. An axially movable rod 54 having arms 52, 53 engaging sleeves 46, 47 carrying the abutments 41, 42 is controlled manually or by a pendulum to provide for an adjustment of the zero elevation position. In a modification, the abutments 41, 43 are secured to the hand levers 33, 36 to limit their relative movement, and the abutments 42, 44 are replaced by an electric arrangement which cuts off the hydraulic pressure when the limits of movement are reached. The indicating pointers are replaced by electric lamps.