GB756238A - Loft ladders - Google Patents

Abstract

756,238. Loft ladders. LOFT LADDERS, Ltd. July 23, 1954 [April 23, 1953], No. 11274/53. Class 20(2). A ladder 1 adapted to be lowered from a loft and spring-biased thereinto through mechanism including a radius rod 3 pivoted to the upper end of the ladder at 2 and to the loft floor at 4, has a biasing means comprising a spring plunger and cylinder device 10, 17, 7 pivoted between the radius rod at 5 and a fixed support 16 within the loft, the spring being compressed within the cylinder when the ladder is lowered. In the mechanism shown, provided at each side of the ladder, short tubes on pins 5 space the rods 6, pivoted thereon, from reinforcing plates 9 riveted to the radius rods 3 ; the rods 6 extend throughout the cylinders 7, and each has a shoulder against which a washer 11 is forced by the spring 10 encircling the rod and abutting at its other end against one of a pair of spaced collars 17 carried by a lug 15 pivoted to the fixed support 16 ; the other collar 17 serves as a stop for a washer 19 held at the far end of the rod 6 by a split pin 20 ; the cylinder 7 is slotted over most of its length to allow passage of the lug 15, and is removably held in place by a split pin 12 passing through the cylinder outside the washer 11, the other end of the cylinder being closed by a cap 13. In a modification, the plungers of spring plunger and cylinder devices are secured to the ends of rods pivoted to the radius rods, while the cylinders are pivoted to fixed supports 16 ; the ladder 1 is slidable in a bracket pivoted to the edge of the loft opening 40 and also in a bracket fixed to the upper side of a downwardly hinged cover for the opening 40. The ladder may consist of a number of slidable sections, and for heavy ladders more than one spring plunger and cylinder device may be provided at each side of the ladder or each device may have a number of springs in a common casing. The pins 5 may be offset from the radius rods 3, or the height of the supports 16 may be increased, or both, to provide an over-centre action at the lower end of the ladder movement to hold the ladder foot on the floor.