GB1415246A - Articulating fitting for a hinged ladder - Google Patents

Abstract

1415246 Lockable hinges; step ladders ZARGES LEICHTBAU GmbH and W KUMMERLIN 5 April 1973 [11 April 1972] 16339/73 Headings E1S and E2F A lockable joint for use in hinged ladders comprises two hinge parts 2, 3 which have hollow portions 6, 7 for connecting to ladder side pieces, a hinge pin 1, and a locking rod 10 which is spring-loaded to move parallel to the hinge axis through complementary holes in the hinge parts; a spring 13 acting on a guide pin 11 which slides within the hinge pin, and the rod 10 and pin 11 being linked by a portion 25 which functions as an operating handle. In the arrangement shown in Figs. 2, 4 a single locking rod 10 is provided and two sets of holes are formed in the hinge parts: one set 19, 20, 21 being used to lock the ladder in its fully extended position (Fig. 3, not shown); and the other set including an elongate hole 18 formed in one of the hinge parts to allow a limited movement between two ladder sections so that they can be used as a step ladder. Further embodiments employ two diametrically opposed locking rods, each linked to the central guide pin, and each engaging associated sets of holes in the hinge parts. The two rods may be either spaced the same distance from the hinge axis and have different cross-sectional sizes (Figs. 5-8, not shown), or have the same cross-sectional size and be spaced different distances from the hinge axis, Fig. 12, (Figs. 9, 10, not shown). Fig. 12 also shows a telescopic form of spring biassing, in which an intermediate sleeve 326 and two springs are employed, enabling the axial extent of the device to be reduced. Further intermediate sleeves and springs can be used.