US2338778A - Ship ladder - Google Patents

Description

Jan. 11, 1944. v w. WELLER 2,338,778

SHIP LADDER Filed Nov. 14, 1942 1i INVENTOR.

Patented Jan. 11, 1944 UNITED STATES PATENT OFFICE SHIP LADDER William Moeller, Jersey City, N. J.

Application November 14, 1942, Serial No. 465,523

'7 Claims.

My invention relates to flexible ladders and more especially ship ladders, i. e., multiple and single types of ship ladders.

It has long been recognized that wood rungs have many advantages over metal rungs in the construction of ladders and lik'ewise'the advantages of chain supports over rope have long been recognized. But the problem of how to attach wood rungs to chain supports has remained unsolved, due to the tendency of the wood to wear and break at the point of attachment under excessive strains incident to use. This is especially true of multiple types of ship ladders where a large number of persons may climb the ladder at the same time causing the ladder to be subjected to excessive vertical forces as great as 1500 to 2000 lbs. The ladder described herein has been tested and has withstood vertical strains as high as 3000 pounds. In order to overcome the difficulty attending the'attachment of wooden rungs to chain side supports or suspensory members various attempts have been made to reinforce the point of attachment of the rungs to the suspensory members but these efforts have failed because the wooden rungs have first been weakened at the point of attachment to the chain supports andthe reinforcements at that point of attachment have not accomplished the desired result.

'My aim has been to construct a flexible ship ladder which would be properly suspended from a fixed point, such as from the commonly used spreaders, so that the wooden rungs would be held away from the side of the ship and at the same time would overcome the difiiculty which has attended the attachment of wooden rungs/to chain supports, thereby increasing the capacity of the ladder to withstand forces of an excessive character.

One main feature of my invention is that I employ metal members which are capable of positioning the chains a sufficient distance from the side of the ship and at the same time function as improved attaching means for the ends of the wooden rungs. Another main feature is in attaching the intermediary chains to the wooden rungs by clamping the links of the chains with-in closely fitting slots formed in an improved manner in the wooden rungs, the links being clamped rigidly within the slots without impairing the flexibility of the chains. Additional features are due to the manner in which the locklink chain, which is the most desirable form of chain, due to its strength and cost, cooperates with the wooden rungsin forming a rigid attachthe rungs by means of :the discs, marked 3, andment, eliminating the undesirable wear of the rungs at the point of attachment without impairing the flexibility of the chains. Furthermore, all these features are secured by a construction which is simple and easy to assemble and inexpensive to build.

Figure l is a front elevation of a multiple ladder.

Figure 2 is a front elevation of a single type of ladder.

Figures '3 and 4 are detail views of the slot and plate attachment for the intermediate chains, parts of the clamping plate being broken away, Fig. 3 being on the lines of Fig. 1.

Figures 5 and 6 are detail views of the disk with the ears or lugs punched from the central part, the rung being broken away in Fig. 6.

Referring to Figure 1, there are preferably employed chains, known as lock-link chains, which are marked l and the wooden rungs are indicated by 2, figure 1 disclosing a multiple ladder and by that is meant a ladder enabling a large number of persons to mount at diiierent parts of same simultaneously. There are illustrated 4 different ladders which can be used at the same time and this construction has been em bodied in an 8 multiple ship ladder that in itself necessitates having a strong construction that will prevent excessive vertical strain-s disrupting the parts.

'Referring again to the multiple ladder illustrated in Figure l, the end chains are secured to these discs have ears 4. (Fig. 6-.) These ears are punched outof the body of the discs, forming sockets which are secured to the rungs by rivets. A link of th chains can be positioned against the outer face of the disc and the cap Shaving curved ends 1' is then positioned against the link in such a manner that the sides of the link are held by the curved ends against, the face of the disc and the cap plate is riveted to the disc. In this way there are formed means for holding the ladder away from the side of the ship or the wall of a building, this disc likewise constituting a connection for the rung and chain. By this construction there is secured a fastening without weakening the end of the rung by perforating the wood or forming slots therein. The intermediate chains are connected to the wooden rungs by a slot connection. As shown in Fig. 3, the rungs are made in sections and each section has a slotted end and then the two slotted ends of adjacent sections are positioned closely together and the plates 8' are then secured by bolts 9 or otherwise to the corresponding ends of the section of the rung, thereby clamping the two slotted ends together, making in effect continuous outer fibrous walls which are reinforced by th metal plates. A link ll having been inserted before the slotted ends are clamped together, and the dimension of the slot being such as to cause the link to fit closely within the slots, insures that the link will be held securely within ,the channel or slot, the plates 8 clamping the parts together, and reinforcing the outer walls at the point where the links are placed. In addition, the twisted ends or knots or looped ends I2 of each link of the intermediate chains extend above and below the wooden rung and in contact with the upper and lower edges of the channels, thereby securely holding the link against vertical movement. It is therefore apparent that both in the case of the end chains and the intermediate chains danger of wear that would weaken the wooden rungs is greatly reduced. In fact the ladder is so strongly constructed that it will withstand a vertical pressure or" some 3,000 pounds. There is preferably shown a square form of rung that is about 1 to 1 /2 inches square and the opening formed in the disc is about 1%; to 1 inches and the width about of an inch. The disc itself is about 5 or 6 inches in diameter; the imperforamd part of the disc is 1 (about) inches in length and about A of an inch in width and the links H of the end chains are so positioned in relation to the disc that upper free ends of the looped or twisted portions of the link contact against the solid part of the disc, as indicated in Fig. 5, while other portions of the link extend above and below this part, so as to insure that flexibility of the chains will not be impaired. It is to be noted that in Fig. 6 the holes in the imperiorated part of the disc are shown ofi center i. e., the major portion of cap plate 6 lies below the central portion of disk, this insures that the links will be properly fastened to the disc in a way to secure flexibility and to obtain the clamping effect due to the free end of the links contacting against the metal of the disc, the imperforate metal portion being marked 13 and the slots or apertures I4. (Fig, 5.)

It is apparent that whereas ladders having only 3 rungs are illustrated, the length of the ladders can be extended to include a greater number of rungs. It is also apparent that at every place where links are secured to the rungs there is the desired amount of flexibility to permit rolling and unrolling the ladders and in the case of the disk connections the aperture or slot l4 permits that flexibility.

All the foregoing objects and still further objects and advantages will become apparent from a study of the foregoing specification and drawing wherein like characters of reference indicate like parts throughout the specification.

Without further analysis, the foregoing will so fully reveal the jist of this invention that others can, by applying current knowledge, readily adapt it for various other types of ladders by retaining substantially the various parts constituting the essential characteristics of either the generic or the specific aspects of the invention and therefore such adaptations should be and are indicated to be comprehended within the meaning and range of equivalency.

Having thus revealed the invention and discovery, I claim as new and desire to secure the following combinations and equivalents thereof by Letters Patent of the United States:

1. Aflexible ship ladder comprising fibrous rungs, flexible lock-link chains and metal discs secured to the rungs, having ears punched out above and below the central portion of the body of said discs, leaving apertures above the imperforated central portion, means for securing the ears to said rungs, cap plates securely holding the links of said chains against the central portion of said disc and the ends of the links extending to the apertured portions of said discs, whereby a link has the desired pivotal movement.

2. In a flexible ship ladder comprising locklink chains and non-metallic fibrous rungs, the combination of metal discs for holding the rungs away from the side of the ship, said discs having metal flanges punched from the central portion to form sockets for the ends of said rungs, the central part of said disc being imperforated, means for securing the flanges to said rungs, cap plates, the links being positioned between said disc and said cap plates, and means for securing said cap plates to said discs for clamping the links against the discs and positioning said lock links so they extend above and below said imperforated central parts of said discs.

3. In a flexible multiple ladder comprising end and intermediate lock-link chains and non-me tallic fibrous rungs, the combination of metal discs secured to the end of the rungs for holding the rungs away from the side of a wall, said disc having metal flanges punched from the central portion to form sockets for the ends of said rungs, the central part of said disc being imperforated, means for securing the flanges to said rungs, cap plates and means for securing said cap plates to said discs, the wooden rungs being formed with narrow slots intermediate the ends thereof, the links of intermediate chains fitting closely within said narrow slots and plates for reinforcing that part of said rungs having the slots therein.

4. In a flexible ship ladder comprising suspended lock-link chains and wooden rungs having solid ends, the combination of metal members having ears punched from the body portion, forming sockets for said rungs, means for securing the ends of said rungs within said sockets, cap plates for securing the links of said chains to said metal members, the twisted ends of said links contacting the imperforated portion of said members to clamp the links to said imperiorated part, parts of said links being positioned within the opening formed by punching the ears from said body portion to permit flexibility of said chains.

5. In a flexible ship ladder, comprising metal chains of lock-link type and wooden rungs, the combination of sections of said rungs having slots in the ends of said sections, the body portion of a link being positioned within said slots and the slotted ends of said sections being positioned contiguously' thereby forming a channel for enclosing the central portion of said links and metal reinforcing plates for holding said rung sections together, the ends of the links being held adjacent said wooden rungs to limit the vertical movement of said links in the said channels.

6. In a flexible ship ladder comprising fibrous rungs and metal chains, having links pivoted together, and metal discs, the combination of ears punched from the central portion of said discs, leaving apertures above and below said central portion, metal plates, means for securing said plates to the central portion of said discs thereby slotted ends of said sections being positioned contiguously, thereby forming a channel for enclosing the central portion of said links and metal reinforcing plates for holding said rung sections together, the ends of the links being held above and below said wooden rungs to limit the vertical movement of said links within the said channels, adjacent links being pivotally connected to said first mentioned links to insure flexibility of said 10 chains.

WM. MOELLER.

Images