US2585134A - Deck hatch structure - Google Patents

Description

Feb. 12, 1952 H. E. KENNEDY 2,585,134

' DECK HATCH STRUCTURE 2 SHEETSSHEET 1 Filed July 10, 1946 lNVENTOR HARRY E KENNEDY BY ATTORNEY Feb. 12,1952 I H. E. KENNEDY 2,585,134

DECK HATCH STRUCTURE Filed July 10, 1946 2 SHEETS-SHEET 2 a JME INVENTOR HARRY E KENNEDY BY ATTORNEY Fatented Feb. 12, 195? DECK HATCH STRUCTURE Harry E. Kennedy, Berkeley,

Calif., assignor, by

mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Application July 10, 1946, Serial No. 682,652

3 Claims.

This invention relates to deck opening construction for ships, and more particularly to an improved hatchway structure especially advantageous in Welded or partially welded steel hull construction.

It is generally recognized that deck openings, such as hatchways, in a ship weaken the ship structure; numerous breakages of ships while in service have originated in the metal structure around a deck opening. The fore and aft tensile stresses imposed upon a rectangular hatchway or deck opening structure, especially at the hatch corners and adjacent thereto, produce high stress concentrations at such points which may ultimately cause fracture there and through the deck plating and hull under various service conditions and. particularly during periods of low temperature. In every instance failure starts at a weld imperfection, or a notch, or a region of changed cross-section; the focus of the failure is an area of high stress concentration resulting from a notch or a discontinuity.

The principal objects of this invention are: to provide a deck opening or hatchway structure which overcomes objectionable features of the constructions heretofore used; to provide a rounded corner structure for rectangular deck openings that eliminates welding along the apex of the corner and avoids high stress concentration and failure adjacent the corner; and to provide an improved supporting structure around and cooperating with a deck opening structure to reduce the rigidity of joints in the supporting structure and lessen the tendency to high stress concentration and breakage in the region of the deck opening.

The above and other objects and the novel features of the invention will become apparent from the following description considered in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of a rectangular hatchway structure embodying this invention, showing a portion of the deck of a ship to which the hatchway structure is secured and also showing a portion of a supporting structure for the deck plating and the hatchway structure;

Figs. 2 and 3 are, respectively, longitudinal and transverse sectional views on the lines 2-2 and (i -3 of Fig. 1 showing portions of the improved hatchway structure and the improved deck and hatchway supporting structure;

Figs. 4 and 4a are, respectively, a plan view and a central vertical sectional view illustrating a portion of a preferred type of corner intersection and supporting structure for the deck plating and the hatchway frame;

Fig. 5 is a sectional view along the line 5-5 of Fig. 1 across a corner of the hatchway structure and the adjoinin intersection of a pair of longitudinal and transverse supporting girders;

Fig. 6 is a perspective view illustrating one of the corner sections of the hatchway structure shownin Fig. 1;

Fig. 7 is a perspective view illustrating a unitary hatchway structure embodying this invention;

Fig. 8 is a plan view illustrating a two-piece welded deck opening structure embodying this invention;

Fig. 9 is a sectional view taken along the line 9-9 of Fig. 8; and

Fig. 10 is a perspective view of one of the two sections of the deck opening structure illustrated in Figs. 8 and 9.

As illustrated in Figs. 1 to 6, inclusive, the substantially horizontal steel deck plating D of the ships hull has a fore and aft elongated opening therethrough which desirably is rectangular and of appropriate dimensions to fit the improved substantially horizontal hatchway structure that is secured to the deck plating around the deck opening to form a border coextensive with the deck opening. In this embodiment of the invention, the improved hatchway structure is a rectangular frame formed of steel ship plate and comprises a pair of side sections A, a pair of end sections B, and four corner sections (It severally secured to the ends of a pair of side and end sections. The inner margin of the horizontally positioned frame forms a four sided rectilinear hatch opening with rounded corners, positioned in a horizontal plane and of appropriate dimensions to provide suitable clearance for loading and unloading cargo.

Each side section A comprises a base In, a flange H, and a rounded portion l2 integrally connecting the base l0 and the flange H, as shown in Fig. 3. Similarly, each end section B comprises a base l3, a flange l4, and a rounded portion l5 integrally connecting the base l3 to the flange l4, as shown in Fig. 2. The side and end sections A and B may be formed of substantially rectangular steel ship plates of substantially equal width and thickness and rolled or pressed in such manner that the transversely rounded portions l2 and I5 thereof, which all have the same large radius of curvature, extend lengthwise of the sections and the flanges II and I4 thereof are substantially perpendicular to the planes of the bases In and I3 of these sections.

As best shown in Figs. 5 and 6, each corner section C is formed of a single piece of steel ship plate to provide a base IS, a right angle flange I1, and a transversely rounded portion I8 integrally connecting the base I6 to the flange I"! and having the same radius of curvature as the rounded portions I2 and I5. The rounded portion I8 extends around the corner section; and the sides I9 and 20 of the flange II, as well as its apex 2|, merge smoothly with the rounded portion I8.

The end edges of each corner section. which have the same cross-sectional shape and area.

as the end edges of the side and end sections, are united by butt welds W to adjoining end edges of a pair of sections A and B. The several side, end and corner sections, so butt-welded'togetnel end to end, provide a metal frame structure wherein'the flange of each section is alined with the flanges of its adjoining sections to form the coaming of a four sided rectilinear hatch opening H having rounded corners.

The rounded portions of the butt-Welded frame sections provide a continuous and wide convexly curved inner surface of considerable sweep facing the hatch opening H and a similar continuous but concavely curved outer surface or fillet. The minimum radius of curvature of the rounded portions I2, I5 and I8 should be five times the thickness of the steel plate of which sections A, B, and C are made; the maximum radius of curvature of these rounded portions should be consistent with structural convenience and pleasing appearance and as shown, the radius of curvature may be about one-half the height of the hatchway coaming. The large radius of curvature of the transversely rounded portion of the frame structure is substantially uniform throughout its length, and its inner and outer surfaces merge smoothly with'those of the base and coaming of the frame. When this frame structure is subjected to high tensilestress, the large fillet provided by the rounded portionsof the frame functions to eliminate stress concentration and failure in the hatchway structure. Tests of a specimen of a hatchway frame embodying this principle of construction have demonstrated that a decrease in the height of the coaming occurred when the frame was subjected to high tensile load lengthwise of the hatchway, indicating that there was a great deal of plastic flow, a flow of the metal of the coaming'into thebase tending to maintain the cross-section of the metal under tension. The elimination of complete right'angle corners and welded corner joints in the planes extending through the apexes 2| and transversely of the hatchway corners also removes areas and discontinuities favoring stress concentration and thus inhibits breakage common in hatchways as heretofore constructed and embodying such right angle corners and welded joints. The rounded inner surface of the hatchway frame provides the further practical advantage of greatly lessening the severe abrasion of the cables and other loading and unloading equipment usually encountered in swinging the cargo under and from beneath the deck.

The hatchway frame structure desirably is, secured to the deck plating by butt welds S which unite the outer peripheral edge of the base of the hatchway frame to the edge of the elongated or rectangular opening in the deck plating D, so that the outer and inner surfaces of the base of the hatchway frame will be substantially flush with the upper and lower surfaces of the deck plating.

The deck plating and the hatchway frame are horizontally supported by and secured to a steel framework within the ships hull and comprisinglongitudinal girders L and transverse girders T. Two pairs of these substantially coplanar horizontal girders provide a rectangular frame extending around the hatchway beneath the base of the hatchway frame to directly support the latter.

The'intersecting ends of these two pairs of girders are severally welded or otherwise united to one another and to other longitudinal and transverse girders terminating at or crossing the intersections. Each of these intersections is located directly below the base member of the corner of the hatchway frame and preferably at a point where the rounded portion of the corner section merges with the base member of the corner section, so that each intersection lies in a vertical plane bisecting or passing transversely through a corner of the hatchway frame and an adjoining corner of the deck opening.

In order to eliminate the rigid joint that would result by welding the ends of the girder webs and flanges directly to one another at these intersections, a hollow metal connecting member, such as a steel tube M or spool M of appropriate length, diameter, and thickness, is inserted and welded in each intersection in such a manner that its longitudinal axis is vertical, intersects the base member of the hatchway structure, and lies in the bisecting plane of the corner. The ends of the girder webs adjacent to'or which, if prolonged, would meet at each intersection may be united to a tube M by welds R 90 apart and extending lengthwise of the outside surface of the tube. The ends of the girder flanges may be united to the tube M by arcuate welds R' spaced apart about the circumference of the tube'M; in the examples shown, the circumference of the tube M is about eight times the width of a girder flange so that a strain at such anintersection allows the tube M to deform to an octagonal shape. As a connecting member in place of the tube M, it is preferable to use a spool type hollow metal member M as shown in Figs. 4 and 4a. Here, the ends of the girder webs are welded to the flanges and not directly to the central part of the spoolmember M, and the ends of the girder'fianges are united by arcuate welds R" to the flanges of the spool M, so that theentire strength of the intersection is built up in the flanges of the member M and the girder webs and flanges welded thereto. The upper end of each member M or M' may be welded to the base of the adjoining corner section C. The joint, constructed at each intersection as disclosed, provides a suitable degree of yield at the regions where the girders intersect; when-a load-and tensile stresses are transmitted from the girdersthrough such a joint, the annular cross sectionof the tube or spool tends to become polygonal shape.

The unitary deck opening structure U illustrated in Fig. 7 is formed from a single metal plate, such as ship plate steel, and embodies the principal novel features of the multi-sectional hatchway frame illustrated in Figs. 1 to 6, inclusive. A central rectangular opening of suitable dimensions is flrst cut through the substantially rectangular plate; then, by a draw ing operation using an appropriately shaped die, the portion of the'plate adjacent and surrounding the away from the plane of the plate to simultaneously form the four flanges 22, 23, 24, and 25, the corners 26, 21, 28, and 29 integrally connecting these flanges end to end, and the continuous transversely rounded portion 30 that extends around the rectilinear hatch opening H and integrally unites the flanges and corners to the base 3| of the resulting frame structure. The outer edge of the base 3| may be butt-welded to the edge of a similarly shaped opening in the deck plating. Otherwise, the corner construction andthe large radius of'curvature-of the rounded portion 30 of the unitary frame U correspond to those of the multi-sectiona1 frame illustrated in Figs. 1 to 6, inclusive.

The deck opening structure Y illustrated in Figs. 8 and 9 is formed of two identical sections J, each of which is pressed from steel ship plate to the shape shown in Fig. 10. The vertical flange of each section J is formed to provide a side 32, two corners 33, and two half ends 34 substantially perpendicular to the side 32. The transversely rounded portion 35 of each section J is coextensive with and connects the flange to the base 36. The base 36 may be provided with a semi-circular edge 31 so that, when the end edges 38 of the two sections J are united by butt welds K, the complete base of the hatchway frame will have a circular edge suitable to be united by a butt weld N to the edge of a circular opening of appropriate diameter extending through the deck plating D. Thus, this construction combines the advantageous circular form of deck opening having no corners and a frame structure constituting a border for such opening provided with the desirable four sided rectilinear hatch opening having rounded corners. The wide transversely rounded portion or base of the fillet between the coaming and the frame has a large radius of curvature at all points including the corners and extends entirely around and has its convex surface facing the hatch opening H", as in the other forms of the invention disclosed herein. Moreover, there are no welded corner joints nor substantial discontinuities in the part of the structure intersected by the transverse planes through the corner apexes of the rectangular hatch opening H". Conditions favoring high stress concentration and fracture at the corners of the structure and in the deck plating are thereby substantially eliminated.

The several forms of structures disclosed herein illustrate the principles of this invention as advantageously applied to hatchways for ships in which both the deck and the hatchway frame are subject to severe fore and aft tensile stresses when the ship is in service. It should be understood that these principles may be embodied in other forms of deck opening structures wherein a rectilinear entrance to the structure is desired, and that certain novel features of the invention may be utilized without others.

What is claimed is:

1. In a ship, a substantially horizontal deck and a hatchway structure forming the border of an opening therethrough, said hatchway structure comprising end sections, side sections and four corner sections, each said side section and end section having a substantially horizontal base, a flange substantially perpendicular to said deck, and a curved portion integrally uniting said flange to said base, each said corner section having a right angle flange, a substantially central opening is pressed or extrudedhorizontal base, curved portions integrally unit ing said right angle flange and said baseoi said corner section, and a rounded portion forming the apex of said right angle flange and integrallyuniting said curved portions of said corner section, said curved portions of said end sections, said side sections, and said corner sections having substantially the same radius of curvature, said radius of curvature being at least flve times the thickness of the material out of which said curved portions are formed, the flange, base and a curved portion of each said corner section being butt-welded to the flange, base and curved portion, respectively, of an end section and a side section, all flanges extending above said deck and substantially vertical thereto to define a four-sided hatch, said bases of said end, side and corner sections being attached to said deck, all of said curved portions being convex with respect to said hatch, said rounded portions being concave with respect to said hatch.

2. In a ship, a substantially horizontal deck; a hatchway structure forming the the border of an opening therethrough, and a supporting structure for said hatchway structure, said hatchway structure comprising a substantially horizontal base, flanges extending above said deck and substantially vertical thereto, said flanges defining a four-sided hatch, adjacent flanges being at right angles to one another, curved portions integrally uniting said flanges with said base, said curved portions being curved convexly with respect to said hatch, and rounded portions integrally uniting adjacent flanges and also adjacent curved portions, said rounded portions being curved concavely with respect to said hatch, said hatchway structure being secured at its periphery to said deck; said supporting structure comprising horizontal supporting members beneath said base of said hatchway structure, and tubular-connecting members beneath and substantially perpendicular to said base, one of said connecting members being disposed adjacent each corner of said hatch, the vertical axis of each connecting member being in a plane which substantially bisects the corner adjacent said connecting member, the ends of said supporting members being secured to said connecting member, said ends being spaced apart around the periphery of said connecting member.

3. In a ship, a substantially horizontal deck and a hatchway structure forming the border of an opening therethrough; said hatchway structure comprising a. plurality of side sections, each of said side sections including a horizontal base portion, a vertical flange portion extending above the deck and a curved portion integrally uniting said vertical flange portion with said base portion, said side sections disposed with the vertical flanges at right angles to each other; and corner sections each having a horizontal base portion uniting corresponding portions 'of adjacent side sections and including rounded portions integrally uniting adjacent flanges and adjacent curved portions of said side sections, said rounded portion of each corner section being curved concavely with respect to said hatch; said side and corner sections defining a four sided hatch, the base portions of said hatchway structure being secured at the periphery thereof to said deck.

HARRY E. KENNEDY.

(References on following page) agassus d REFERENCES "cIT'EI'i -UNITED STATES PATENTS Number Name Date Stratton July 10, 1894 Lake June-22,-1909 Knapp Dec. 18,1917 Davis July 29, 1919 Thomas Oct. 25,1927 Ronk A-pr.--'29, 1930 'Chafiee at 9,1. Nov. 8,1938

'Nixmber Number Name Date 'Zerbe New '14, 1989 Jenkins :Ma.r. 31, 1942 FOREIGN PATENTS Country Date Great Britain May 26,1931 Great Britain 'Sept. 5, 1932 OTHER REFERENCES Publication: PraticaLDeSign for Arc'Welding," rpl ates by "Robert'E. Kirikead (Plate 12, Mar. 3, 1944) (Plate 54, Sept. 22, 1944).

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