US2582436A - Metal hatch pontoon - Google Patents

Description

. Jan. 15, 1952 K. W JERNSTROM 2,582,436

METAL HATCH PONTOON Filed June 5, 1947 2 SHEETS-SHEET l 1952 K. W.JERNSTROM METAL HATCH PONTOON Filed June 5, 1947 2 SHEETS-SHEET 2 INVENTOR. 4452 d P/wT/Pwv A TTOR/VD S Patented Jan. 15, 1952 METAL HATCH PONTOON.

Karl W. Jernstrom, Verona, N. J asslgnor to Seaboard Machinery Corp., New York, N. Y., a corporation of New Jersey Application June 5, 1947, Serial No. 752,734

This invention is a metal hatch pontoon having the advantages over prior art pontoons, of lighter weight, so it may be handled more easily, combined with an economically sound manufacturing cost and the ability to adequately meet the specifications for ship hatch pontoons set by recognizedagencies, that must pass on naval architecture, such as the American Bureau of Shipping. a r

Certain of the broader phases of the present invention are disclosed and claimed in a copending application filed June 5, 1947, by the same inventor and entitled Metal Hatch Boards," said application bearing Serial No. 752,733.

A specific example of this metal hatch cover pontoon, having the advantages and meeting the conditions noted, is illustratedby the accompanying drawings in which:

- 4 Fig. l is a perspective view showing the use of the pontoon; Fig. 2 is a top view of the pontoon;

Fig. 3 is a cross section taken from the line 3-3 in Fig. 2; 1

- Fig. 4 is a longitudinal section taken from the line 4-4 in Fig. "3; and v Figs. 5 and 6 are perspective views of details of the pontoon.

More specifically, these drawings illustrate a ship hatch cover pontoon made of metal and comprising two substantially rectangular channels each having a web I and flanges 2, arranged mutually parallel with the flanges of one extending towardsthose of the other in mutually spaced alignment at similar web side edges. The flange side edges 3 of each of these channels and remote from the web I, are integrally provided with flanges 4 rectangularly extending from these flange side edges 3 toward the channel center and terminating in mutually spaced relation, in each instance to define with the channel a rectangular .box section having a longitudinal slot 5 giving access to its interior.

The second-named flanges 4 are substantially thicker than the web I, in the case of each of the channels, and a channel having a web 6 and flanges 7, is arranged with its web 6 flush with an aligned two of the first-named flanges 2 and with its flanges 1 extending in the same direction and contacting and being fastened to the second-named flanges 4 extending from said two of the first-named flanges 2. The flanges 4 and I are interfastened by screws and nuts 8.

Because the flanges 4 are thicker respecting the web I, each longitudinally slotted box section provided by the first-named channels and 1 Claim. (01. 189-46) their parts, has approximately the same strength as a fully closed box section of conventional con struction, while providing the advantage of the slot 5 which afiords access to its interior. A critical improvement, this being the equality of the strength of a fully closed box section of conventional design, is obtained by making the flanges 4 with thicknesses greater than required to make their cross-sectional areas equal that of the channel web I of which they are parts. This is of particular advantage when these webs I are wider than their first-named flanges 2.

The maximum thicknesses of the flanges 4 should be kept within reason consistent with obtaining the objective of a strength comparable to a fully closed box section. To provide an "example, when the flanges 4 are approximately each one-third as wide as the web I, they should be made approximately two times as thick as the web.

Due to the composite construction of this new pontoon, all of the parts required to produce a pontoon of adequate size, such as one approximately 14 wide, 12 long and having a depth of a trifle more than 8%", may be produced with the parts individually of such size as will permit them to constitute light-metal alloy extrusions, as exemplified by high strength corrosionresistant aluminum or magnesium alloy extrusions. This permits the making of the flanges 4 thicker than the webs l and flanges 2 with all these parts integral, and the flanges 6 and I may be made of integral parts. A factor of great importance is that this results in all the parts being substantially free from a transversely strained grain structure, which would be greatly detrimental to the carrying of beam stresses by the pontoon. Any straightening of the extruded parts may be done by stretching, which does not introduce transverse strain to the rain structure of the metal. Incidentally, strain in the grain structure may be microscopically observed by any competent metallurgist, so its presence and direction is determinable.

Each end of the pontoon is closed by a lightmetal alloy end casting comprising a web 9 having slots l0 fitting around the flanges 4 and 1 so that the web 9 can be positioned flush respecting the pontoon end. A flange H surrounds the entire periphery of the web 9 including its slots l0, this flange fitting inside the pontoon end and being riveted or spot or plug welded to the latter. Other forms of end closures may be used, but the one just described is particularly preferred.

The lateral stability of the pontoon is increased by a plurality of strut plates, each providing an upstanding wing l2 that projects upwardly between the flanges 1 and is provided with a flange l3 fixed to the web 6, each strut plate also having laterally projecting Wings 14 which extend beneath the flanges 1 to the web I where they are fastenediby 'end Jflanges I1 5 on the wings ifll. 'I'he strut plate'flanges maybe fastened as indicated, by means of rivets or by spot or plug welding. The stiffness of the plate 12 is increased by :a bottom flange 16.

The necessary handles are generallyindicated by 11, these being preferably =.of .the flush type and welded or riveted in place. The necessary apertures in the web 6 for the basins of these handles do not materially affect the structural properties of the pontoon, particularly if the handle basin is peripherally welded or riveted-to-;the periphery of its hole in the web 6.

slitsmay now :be appreciated that this: invention provides a :pontoon which can be produced at ,an :economicallysound cost, yet one whichisexcep- :tionally light weight-in character and Whichhas much greater corrosion resistance than when -made.;from, steel, for example. The described box :sections are of ;great.strength, yet they provide 180C955 slots permitting the fastening .of the screws andnuts- 8mandnthe installation :of plates 9.

,Rivetinginay be reasily accomplished-by .theuse of appropriate .blind rivets. .The beam strength of the pontoon meets all standardrequirements. :All the extruded parts can be made by presently available equipment because the design of the pontoon permits the individualparts to be vkept within the limits of conventional extrusion ;presses. If the screws and nuts '8 are made of rsteeL-they should be heavilygalvanized or. cad- ;miumplated, and the rivets :should beof the mentioned light-weight alloy.

I claim:

:A metal ship .hatch "pontoon comprising two substantially rectangular channels each having :a web and flanges, :arranged mutually parallel :with the-flanges -,of one extending toward those of the other in mutually spaced alignment at similar web side edges, with the flange side edges, of each of said channels and remote from the web integrally provided with flanges rectangularly extending from said flange side edges toward the channel center and terminating in mutually spaced relation, in each instance to define with :the \channel ;a :arectangular box section having a longitudinal slot giving access to its interior, and a channel having a web and flanges, arranged with its Web flush with an aligned two of the firstnamedflanges and its flanges extending in the same direction and contacting and being fastened totthe'secondnamedflanges extending from said itwo of the first named flanges, said second-named flanges of said first-named channels, having thicknessesgreater than required to make their total cross-sectional area equal that of the channel web of which they are parts, the webs of said first-named channels being wider than their flrst spaced longitudinally of said channels.

KARL -W. .JERNSTROM.

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

UNITED STATES "PATENTS Number Name Date 426,559 Dithridge Apr..29,;1890 835,578 Tanner Nomi-3, 1906 1,085,429 ,Kahn etial. Jan. ,27, 1-914 1,777,879 Ewe'rtz et a1. Oct. 7,1930

1,986,998 Burgess et a1. Jan. 8,1935 2,101,056 .Frick l .Dec. 7,1937 2,485,165 Pollman Oct.18, 1949

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