US1869329A - Frame system for ships of iron construction - Google Patents

Description

y 26, 1932- G. F. K. WROBBEL 1,859,329

. FRAME SYSTEM FOR SHIPS OF IRON CONSTRUCTIQN Filed June 17, 1926 Patented July 26, 1932 UNITED STATES PATENT OFFICE Gusrav rammucrr m1. WBOBBEL, or nairnnne, GERMANY FRAME SYSTEM FOR SHIPS OF IRON CONSTRUCTION Application filed June 17, 1926, Serial No. 116,748, and in Germany June 20, 1925.

which the structure is liable to be subjected.

The expression iron ship construction is herein employed to denote that system of construction which is generally adopted in iron ship-building in contradistinction with t1 mw ber ship-building and ferro concrete sh1pbuilding, irrespective of the actual metal used (ingot iron, steel, aluminium or other metal or alloy). v

Heretofore ships have been built accord- 35 ing to the transverse frame system or to the longitudinal frame system. As is well known the construction of the ship, which has to sustain the stresses in longitudinal direction constitutes a box-girder, the webs or'walls of which are thin in comparison to the dimensions, and therefore, are subjected to the risk of being crushed or bent. The plates or areas of the outer skin, as far as they are below the waterline and the bottom are subjected to bulging or bending strain by the pressure of the water, owing to which the material in the center of the plates or of the areas will be impaired with regard to their capability of sustaining the stresses in the longitudinal direction.- The bulged out parts flex or spring under the influence of the longitudinal forces, and the transmission of the compressive forces are borne merely by such portions of the plating, which are securely held by adjacent stays. The shearing forces which arise tend to distort or displace the comparatively thin webs of the box-girder (outer skin). This is only prevented .by the frames. Since generally speaking only part of the frame work is constructed as a closed structure the usual frame connection serves mainly for locally stifiening the outer skin and the decks against the risk of crushing owing to longitudinal and torsional forces, whilethe cross bracing proper of the ship is formed mainly by bulkheads and main frames. The longitudinal frame system presents over the transverse frame system greater rigidity because the cross bracing is considerably strengthened by the arly disposed main frames, while lines a denote the side or the bottom ribs or the longitudinal bracing is strengthened by the copious longitudinal frames, over the ordinary cross frame system. Nevertheless, a large portion of the longitudinal frames situated near the neutral axis have merely a local significance and are wholly insuflicient i for longitudinal strength or rigidity.

Contrary to the heretofore usual system of ship building, the present invention proposes a diagonal frame system which is well adapted for metallic vessels of any kind and size. In such diagonal frame system those portions of the outer skin and of the decks which-owing to their position with regard to the neutral'layer of fiber are not able (55 to increase substantially the longitudinal strength of the ship, are constructed only as strong as is necessary for them to withstand the local stresses in combination with. the transverse and longitudinal strains. The 70 strains in general, however, are taken up as far as possible by a diagonal bracing system which is ositioned directly or indirectly on the lateral outer skins, on the bottom and on v the decks. In addition to strengthening the hull of the vessel against strains due to longitudinal transverse and torsional stresses, the practice of the present invention results in a saving of the requisite material which is in sharp contrast to the heretofore usual construction on which alone, the prescriptions of the classification societies have up to the present time been based.

In Fig. 1 of the accompanying drawing the main frames of a ship or they may represent the deck beams, these lines being intersectedby diagonal lines representing a diagonal frame. In Fig. 2 the lines I) represent the longitudinal frames intersected by diagonal lines representing a diagonal frame. Fig. 3 is a perspective view illustratin diagram-" matically the arrangement 0 diagonal frames applied to the sides, deck and bottom of the ship. The new idea of providing a diagonal frame system overthe heretofore usual systems of construction and those disclosed in patents up to the present time resides in the fact that, while retaining the main connections relied on to obtain longitudinal and transverse strength (that is to say, not only stresses, especia the longitudinal connections or frames whic are efiective by reason of their osition relatively to the neutral axis but a so the transverse bulkheads and transverse main frames),

' those frames which are less capable of ofieriniresistance but make just as im ortant contri ution to the ultimate stren by taking p onal framesas to be adapted to ta e up incldental thrust or shearin also take up a share of t e total or ultima stresses.

What I claim is:

1. An iron ship consisting of a lattice-girder-systcm of diag onal braces adapted to withstand by itself "the ly the torsional stresses.

2. An iron ship construction comprising a frame work constituting the bottom, the

sides and the deckof a ship, said frame working consisting of a'lattice-girder-system composed of diagonal braces, said lattice-girdersystem being self-resistant to the stresses, especially the torsional stresses, platings provided besides said frame work, said latings being merely adapted to take up t 0 local stresses.

Intestimony whereof I have signed my name to thls specification. GUSTAV FRIEDRICH KARL WROBBEL.

messes thrust stressesare so brace b the diagstresses and thus 7 construction comprisin a .frame work constitutin the bottom, the si es, and the deck of the s 'p, said frame work

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