GB586451A - Improvements in step ladders and trestles - Google Patents

Abstract

586,451. Step-ladders. ALLAN, J. July 20, 1944, Nos. 13947 and 13948. Convention dates, Aug. 28, 1943, and Oct. 23, 1943. [Class 20 (ii)] The supporting prop of a step ladder or trestle,. pivotally connected to the front portion thereof, comprises a longitudinally disposed member or strut, a cross member pivoted intermediate its ends to this strut, a pair of prop legs one on each side of the strut and pivotally connected to said cross member, and link means spaced from said cross member and pivotally connecting the prop legs, said link means forming a guide for the strut during transverse movement thereof relative to the prop legs when the ladder is being set up on uneven ground. Alternatively the longitudinal strut may be pivoted to the link means intermediate the prop legs. The link means preferably comprise two links one on each side of the prop legs and pivoted thereto, forming a slot in which the strut works, the links also being capable of being arranged to extend adjustably between the prop legs and the strut for which purpose the strut is provided with a series of holes or a slot. The figures show the back prop arranged in three different ways. In Fig. 4 the front part 10 is on even ground and the prop legs 17 and cross member 16 have moved to take up an inequality. In this case the links 18 connect the prop legs directly and the longitudinal strut 13 is pivotally attached to the links by a bolt 21. In Fig. 5 the front portion is enabled to stand on uneven ground by removing the bolt 21 and allowing the strut 13 to swing in the slot formed by the links 18. The strut may be clamped in the adjusted position by suitable means, (not shown). In Fig. 6 one end of each link is disconnected from a leg and connected to the slot 22 in the strut by a common bolt 21, which can slide up and down the slot to enable the legs 17 to be moved towards and away from each other. Two possible positions are shown in full and dotted lines, the former enabling the prop legs to be placed in a constricted position, such as the corner of a room. The legs may be clamped in the desired position by wing nuts on the bolts 20, 21. Other arrangements of the legs may be obtained by extending one link from one prop leg to the slot 22 and the other from the other leg to the end of the strut 13.