US2542923A - Ladder - Google Patents

Description

A. E. HALLEN Feb. 20, 1951 LADDER Filed June 16, 1947 Patented Feb. 20, 1951 OFFICE LADDER Alf Eskil Halln, Goteborg, Sweden Application June 16, 1947, Serial No; 754,803 In Sweden June 1'7, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires June 17, 1964 1 Claim.

This invention relates to gangway-ladders and similar at least partly unsupported ladders which are provided with high beams, such as side beams or string-boards, for taking up bending stresses acting on the frame of theladder. The invention has for its object to provide a construction which enables the ladder to be collapsed from a service position into a stowage position in which it requires a minimum of space. The invention is advantageously made use of in connection with ladders in which the beams or string-boards arranged on either side of the ladder are constituted partly .by the longitudinal frame tubes or the like members which support the steps of the ladder; and partly by a back member for reinforcing said frame tubes.

The invention is described more in detail hereinbelow with reference to an embodiment illustrated in the annexed drawing; in which:

Fig. l is a side elevation of a gangway-ladder arranged in accordance with. the invention;

Fig. 2 is a cross-section of the ladder;

Fig. 3 shows a portion of the frame tubes of the ladder to a larger scale than the preceding figures; and Fig. 4 shows a section along the line IV-IV, Fig. 3.

In the drawing, numeral I indicates the upper platform and 2 the lower platform of the gangway-ladder. The steps indicated at 3 are pivotally connected to longitudinal frame tubes 4 which are arranged on either side of the ladder and connected to each other by means of transverse rods not shown in the drawing. The steps of the ladder and the platforms are interconnected by means of a guide rod 5 pivotally secured thereto in a manner such that the steps and the platforms always will be parallel to each other and in horizontal positions irrespective of the angle of inclination of the ladder. The frame tubes 4 are further pivotally connected with uprights i 6 for handrails l. The handrails are in. known manner adapted to be adjusted in accordance with the angle of inclination of the ladder, the upper ends of the handrails being articulated to uprights B which are rigidly connected with the upper platform 5. If, for instance in order til stow away the ladder, the platforms l and 2 are swung into alignment with the frame tubes 4, the steps of the ladder and the handrails will be swung, too, so as to be located substantially 5 in the same plane as the frame tubes, as indicated in Fig. 2.

In order to obtain a ladder frame construction. of great resistance to bending stresses, high side beams or string-boards are used. These side 10 surrounding. the frame tube 4. construction, the back members 9, l I of the side 2 beam constructions increase, however, the'stowage space for the ladder, and the height and power of resistance of the side beam constructions would consequently be chosen with regard tothe point of view of space saving. To avoid this inconvenience, portions of the string-boards are, in accordance with the invention, swingably longitudinal stay irons 9 consisting of tubes of smaller dimensions than the frame tubes 4. Each longitudinal stay iron 9 is curved at least at its ends where it is pivotally connected with the frame tube 4, such as by means of sockets It surrounding the tube 4. Between its ends, the stay iron 9 is rigidly secured to preferably oblique stays l l which are rigidly connected to sockets Due to this beams or string-boards are swingably connected to the appertaining frame tube 4% so that they can be swung into the position shown by dot and dash lines in Fig. 2, close to the steps of the ladder and in a plane parallel to the plane of the ladder in its collapsed stowage position.

Due to the arrangement described, the ladder, in collapsed position, has a thickness of about half only of the corresponding dimension of hitherto commonly used gangway-lad-ders of the same type having fixed string-boards. Since the gangway-ladders of a ship normally are stowed in a recess in bulwarks on a suitable deck, such recesses can be diminished to a corresponding degree, which is of great importance to the space on deck, particularly laterally of deckhouses.

Even in long ladders for large vessels, the string-boards constructed according to the invention can, without difiiculty, be made so strong that the ladder can be disengaged from its normal suspension members on the gangway-davit and swung outward to the quay so that the lower ends of the string-boards will rest on the quay, and the string-boards will be unsupported between their upper and lower ends. The longitudinal beams or string-boards and the associated stays may advantageously consist of tubes,

and, since they further may be relatively high The bearing socket has a peripheral recess 17.

for a stop member 18 rigidly secured to the wearing-ring IS. The stop member may be attached by means of a slot weld 19. The recess 1! and the stop member 18 may be dimensioned such that the socket I can be turned through 90 between its abutting positions relative tothe stop member. In order to prevent weakening of the socket [0 by the recess H, the socket is bridged over by a member 20 which interconnects the 7 portions of the socket separated by the recess.

The gangway-ladder is usually suspended on a davit, the suspension wire being diagrammatically indicated at 25 in Fig. 1. By means of a crow-foot, said wire is connected to suspension mountings on the ladder. These suspension mountings 26 are preferably, such as by welding, rigidly connected with the appertaining bearing sockets l0. As will be seen from Fig. 4, the mounting 26 is eccentrically welded to the socket 10. When the ladder is hanging on the mountings 26, the suspension forces will give rise to a turning moment actin on the bearing socket 10 such as to maintain the socket in firm contact with the stop member 18. As a result thereof, the tendency of external forces, if any, to swing the string-boards inwardly towards the plane of the ladder is eliminated. Obviously, a locking device, such as a pin, for keeping the swingable portion of the string-boards in proper position when the latter is used maybe provided instead of, or simultaneously with the above suspension device.

Instead of the bearing socket described above, hinge-pins provided On the swingable stringboards and cooperating with corresponding members on the frame tubes 4 may be used as bearing means.

What I claim is:

1 A gangway ladder comprising longitudinal frames, step members supported by said frames, reinforcing members for said frames, each reinforcing member includin a longitudinal stay member, connecting stay members secured to said longitudinal stay member, bearing members secured to said connecting stay members and pivotally mounted on said frame, whereby to render possible swinging of said reinforcing member'about said frame from a service position substantially at right angles to the plane of the ladder towards a plane substantially parallel to the plane of the ladder, suspension mountings for the ladder, and stop members secured to said frames, said suspension mountings being eccentrically connected to and rigid with said bearing members such that the suspension forces acting substantially vertically on said mountings will tend to turn said bearing members-towards said .stop members whereby to keep said reinforcing members in proper service positions below said frames. I ALF ESKIL HALLEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 1 Name Date 175,095 Hoehn Mar. 21, 1876 298,212 Knight May 6,1884 735,371 Hayward 1 Aug. 4, 1903 788,424 Ochs Apr. 25, 1905 1,221,156 Dotson Apr. 3, 1917 1,233,686 Moore July 17, 1917 2,220,155 Jachim Nov. 5, 1940

Images