Patent GB-311390-A (GB)
Title: Improvements in or relating to stairways
IPC: E04F11/04
Filed: 1928-07-25
Abstract: 311,390. Bessler, F. E. May 12, 1928, [Convention date]. Ladders.-Access to attics or other upper rooms in buildings is had by means of a ladder which normally occupies a vertical position in a recess or cupboard in the wall but which may be brought to inclined position to lead to a trapped opening in the ceiling by a motor which is controlled by the movements of the ladder. The trap, a handrail or rails, and the recess or cupboard door may be interconnected with the ladder so that the parts are all operated automatically. The ladder is supported at its upper end by a cradle formed of bars 48, 52, 53, Fig. 4, the upper bar of which 48 is hinged by hinges 45, 46 to a lining plate 6 on the side of the ceiling opening 5; the bars 48, 52 are connected together at their ends by bars 55 which are adapted to slide in grooves 56 in the ladder stringers as the ladder is moved from vertical to inclined position, the mction being limited by stops 58, 59, Fig. 5. A handrail or handrails 60 is or are adapted to occupy normal positicns outside the ladder stringers, being supported by radius rods 64 from the stringers; the upper radius rod is pivoted at its outer end to a bracket 62 on the handrail and a telescopic rod 75 is connected at one end to this bracket and at its other end to the cross rod 52 of the cradle. As the laeder is drawn from the vertical to the inclined position the rod 75 at first telescopes until the end of one part contacts with a stop 82 on the other part, Fig. 7, whereupon the handrail is raised, a stop 85 on the rod passing behind a lip 84 on the bracket to maintain the rail in raised position. The reverse motion ensues and the rail is lowered when the ladder is 'pushed again into the vertical position. The celling aperture is adapted to be closed by a hinged two-part flap 90, 91, Fig. 1, one end of one flap portion 90 being hinged at 95 to the rear side of the celling aperture while the free end of the other flap portion 91 is provided with rollers 99 adapted to roll on the rack bars 100 supported by aperture lining-bars 10. Racks 108 on the ends of these bars operate gears 109, 110 to which latter are fixed levers 111 having a pivotal sliding connection to the flap portion 90, so that the flaps are operated to close and open the ceiling opening. The rack bars are slidably mounted and are actuated automatically from the ladder cradle by means of levers 105, Fig. 4, pivoted to the rack rods and to the ends of the bars 48 of the cradle, so that movement of the cradle about its hinges 45, 46 causes movement of the levers. The inner ends of the rack bars are held downwards by rollers 106 mounted on the ends of wings 8 of the recess lining-plate 6. The door 4 of the recess or cupboard may be operated by hand, but preferably it is operated automatically on movement of the ladder. To effect this, a latch 126 is pivotally mounted on a bracket 127 in the ladder recess and this latch is provided with a pivoted nose portion 132 which is moved inwards on the latch during the first motion of the ladder in the recess from the vertical position by an extension 138 of the roller axis 17 disposed at the bottom of the ladder. The stop then contacts with a face of a recess in the latch and definitely moves the latch about its pivot, a spring 130 causing quick movement of the latch, to open the door through a link 124 and pivoted connection 125, Fig. 15. On the return of the ladder, the extension contacts with the pawl 132 and presses it and the latch backwards, thus closing the door. The power unit comprises a motor 21 and gearing 22, 23 and an automatically controlled clutch 24, 25, and is controlled automatically by the movements of the ladder through a switch-box 36 disposed in the ceiling opening. The rolling wheels 18, which may be rubber covered, are loosely mounted on a cross-shaft 17.