GB539251A - Improvements in or relating to step ladders and ladders - Google Patents

Abstract

539,251. Step-ladders. WESTON, T. May 1, 1940, No. 7852. [Class 20 (ii)] A step-ladder comprises. a ladder portion, a pair of supporting legs pivoted thereto so as to move outwardly with respect to each other as they are moved outwardly from the ladder, and pivoted tie members for the legs to limit their outward movement. The legs 1 are pivoted to blocks 18 mounted on a rotatable shaft 2 on the ladder and are inter-connected by crossed bars 9 each of which is pivoted at one end to a leg and at the other end to a sliding sleeve 8 on the opposite leg. Pivoted stays 5, one on each side, are pivoted to blocks 26 at the ends of a further rotatable shaft 6 on the ladder portion, and also to the squared ends of bolts 27 on the sleeves 8 of the leg on each side, the other ends of the bolts serving as pivots for the ends of the crossed bars 9. As the legs are moved outwardly from ;the ladder, the sleeves on the legs are raised by the ties 5, and .the .crossed bars 9 move the legs apart. The extent of the opening is controlled by a stop plate 11 which may take the form of a simple plate secured to each leg or may comprise a resilient extension plate 32 which can be adjusted to and from the leg to form an alternative stop for a different position. Tension springs 12 may be used between the upper end of each leg and the sleeve 8 thereon to cause automatic opening of the legs and when the ladder is closed lock plates 13 on the ladder serve to lock it in that position. The springs may be disposed in grooves in the legs. The joints between the legs and the ladder and the ties and the ladder may be ball and socket joints to allow universal movement. A cord 40 attached to a lever 43.on each side of the ladder D may be used in conjunction with a shorter spring.46 to effect the.opening and closing of the ladder.