US2397952A - Ladder construction - Google Patents

Description

A ril 9, 1946. F. A; ELLIS f 2,397,952

LADDER CONSTRUCTI ON Filed Aug. 5; 1944 INVNTOR rick A.E5

ATTORN E'Y Patented Apr. 9, 1946 UNITED STATES- *PATENT OFFICE LADDER 'CONS TRU'CTION Frederick A. Ellis, Binglanton, N. Y., assignor to N ol L. Dahlander, New Milford, Pa.

Application August 3, 1944, Serial No. 547,830

2 Ciaims. (o1.223`--40) This invention relates to ladders in general and more especially to ladders such as multiple or disembarkation ladders, and single ladders such as pilot's ladders, Jacob s ladders or engine escape ladders.

Among the objects of the present invention it is aimed to provide an improved ladcler construction consisting of, fiexible suspensory members such as chains, and rigid rungs pivotally connected at their ends to links of the chains.

It is another object of the present invention to provide an improved ladder constructicn having a reinforced rung ccmposed of metal with a broad tread suitable for use either with a single ladder or multiple ladder.

These and other features, capabilities and advantages of the invention will appear from the subjoined detail description of specific embodiments thereof illustrated in the accompanying drawing in which v Figure 1 is a front elevation of a ladder made according to the present invention.

Fig. 2 is an enlarged fragmental detail of a part thereof. v

Fig. 3 is a section on the line 3-3 of Fig. 2'.

Fig. 4 is a section on the line 4--4.

Fig. 5 is a fragmental front elevation of part of a multiple ladder made according to the present invention.

In the embodiment shown, in Figura l, there are provided two suspensory elements l and 2 having rigid rungs 3 pivotally connected thereto.

The suspensory elements l and 2 are preferably fiexible and composed of chains. When these chains are composed of lock links 4 as shown, excellent results have been achieved, particularly when the lock links are arranged with their looped ends at the bottom and their connecting fingers 5 at the top. Preferably the fingers 5 of the uppermost link of each suspensory element l, 2 is connected by a rivet G to the fingers 1, 8 of a lash receiving link 9. The links 9 in the present instance have reenforced shields and extend through the lash rings n, lt'. These lash rings H] are provided to facilitate connecting the upper ends of the ladder to the upper deck of the vessel or other abutment in the usual Way. To protect the hands of the user in severe weather, particularly in extreme temperatures, the suspensory elements l and 2, when composed of metal chain links such as here shown, are generally covered with a protective material such as canvas or the like. Tubes of canvas sometimes called "Socks" are provided which are mounted upon chains between succeeding rungs and above and below the uppermost and lowermost rung, respectively. In the present instance, two short tubes I I and !2 are mounted upon the suspensory elements l and 2 above the uppermost rung 3 and secured in place by grommets !3. Excellent results have been achieved when lock links are used, since they permit the securing of these tubes ll and !2 by grommets l3, one at each end of a tube I I, !2, the grommet passing through a lock link 4 at each end of a tube ll, !2, Between successive rungs 3, in the present instance, longer canvas tubes !4, l5, are provided, also secured in place bygrommets as aforesaid, such as the grommets [6. V

'The rungs 3 here illustrated have certain inherent advantages. In some instances, metal rungs are desirable. Excellent results have been achieved when these rungs were composed of sheet metal. However, when the rungs were hollow or ch'ambered, especially when the' chains were used in the war eii'ort, it has been found that due to concussion and the like, the chambered rungs frequently Collapse or explode, leaving ragged edges. In the interest of strength a solid fiat sheet was objectionable as Compared to a chambered' Construction. To overcome the aforesaid objections, the present Construction was contrived, it being practically immune to damage from concussion.. According to the present invention the rung 3 is composed of a single sheet of metal which is folded over into a T-shape, see the cross section in Fig. 3 with an upper broad tread portion I' folded back upon itself to form the lower portions |8 and l9 and terminating in the two flanges 20 and 2! disposed adjacent to one another and extending substantially at right angles to the portion Il. The tread portion IT and lower portions !8 and !9 at their ends 22 and 23 are slightly deflected downward, presenting not only a smooth curved outer surface, but also downward inclining edges. These edges 22 and 23 contribute materially to the comfort of the user. The ends of the rungs are pivotally connected to links 4 of the suspensory elements l and 2. In the present instance, loops 24 are formed at the ends of clips having two parallel fianges 25 and 26 which engage the outer faces of the ends of the flanges ZO and 2| and are riveted thereto by two rivets 21 and 23. These loops 24 thus formed at the ends of flanges 20 and 2! are in the present instance secured in place by the fianges 25 and 26, although obviously other means may be provided for securing the loops at the ends of the fianges 20 and 2| without departing from the spirit of the invention. The

loops 24 asshown enclose or grip a shank 29 of a link 4, see Fig. 4. Advantage is here taken of the vertically extending shanks, such as the shanks 29 of the lock links 4. In the actual use of these ladders, particularly in the War effort, experience has shown that when the men are taught to grip the suspensory elements when climbing up or down the ladders, less injuries result. In other words, if in the excitement of disembarking the man below was engaging the rungs 3 with his hands, the succeeding man might step on his hands and materially injure the same when consideration is taken of the heavy pack carried by the men, in addition to the weights of the men themselves; The present rungs also contribute in this respect, compare the former smooth cylindrical rung which readily fits the hollow of the hand to this T-shape Construction.

In this Way the men in their excitement will ini tuitively prefer grasping the canvas covered suspensory elements I and 2 and shy from grasping the T-shape rungs; When consideration is taken of the injuries that also flow from the engagement of these rungs by the bare hand in extremely low temperatures; any improvement r that would tend to induce the user to refrain from engaging the metal rung'must be considered as material.

With 'the present formation of rung 3 it has *also been found that the main portion of the rung, including the'elements' ll, !8, iS, and 2I may be composed of aluminum having the thickness of .081 inch. When this rung proper is so composed of aluminum, excellent'results have been achieved When the clips, including the loop 24, and fianges and 28, are composed of galvanized sheet iron of about 125 inch in thickness.

As shown in Fig. 5, this Construction of rung 3 can also be used toadvantage in theproduction of a multiple ladder 'as distinguished from v a pilot's ladder; v

, The rung 3 and end clips canpof course, becom-` posed of other metals without departing from the `general spirit of the invention. As an instance,

excellent results have been achieved When the rung element 3 was produced from sheet metal having a thickness of .031 inch to'.037 inch and the clip elements 24, 25 and 26 were composed of sheet steel having a thicknes of from .078 inch to .125 inch, both rung elements 3 and clip element 24, 25 and 26 being preferably galvanized.

It is obvious that various changes and modifications may be made to the details of Construction withoutdeparting from thegeneral spirit of the invention as set forth in the appended claims.

I claim:

' 1. In a ladder the combination of fiexible susr pensory elements, and rungs connected at their ends to said suspensory elements, each rung composed of a sheet of metal, T-shaped in cross section With'the sheet of metal having its intermediate portion forming the tread and its two end portions bent into right angles 'with the two I leg portionsof the right angles adjacent the tread folded under the tread into intimate engagement with the same and its other leg portions disposed adjacent to one another into intimate engage- *ment With one another at right angles to the tread, and the ends of the intermediate portion and adjacent leg portions being deflected downwardly to form smooth curved outer surfaces and downwardly inclining edges. i

2. In aladde' the combination of aplurality of chain suspensory elements; rungs, each rung composed of a sheet oi metal, T-shaped in cross section with the sheet of metal having its intermediate portion iorming the tread and its two end r portions bent into right angles with the two leg portions of the right angles adjacent the tread folded'under the tread into intimate engagement with the same and its other leg portion disposed adjacent to one another into intimate engagement with one another at right angles to the tread, and the ends'of the intermediate portion and adjacent leg portions being defiected downwardly to form smooth curved outer surfaces and downwardly inclining edges, met-al clips, each metal clip having a loop pivotally preceiving a' shank of a chain ink and having fiangesengaging the cuter faces of said other leg portions, and rivets extending through the fianges and encloed intimate engagement With one another.

FREDERICK A. ELLAIS.

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