US3394834A

US3394834A - Single-locking closure plate for cargo tankers

Info

Publication number: US3394834A
Application number: US649989A
Authority: US
Inventors: Irving L Cigliano
Original assignee: MMC International Corp
Current assignee: MMC International Corp
Priority date: 1967-06-29
Filing date: 1967-06-29
Publication date: 1968-07-30
Anticipated expiration: 1985-07-30
Also published as: DE1531645B2; DE1531645C3; FR1548817A; NL6717226A; BE710604A; DE1531645A1; GR34822B; CH464724A; GB1206806A

Description

y 30, 1968 I. L. CIGLIANO 3,394,834

SINGLE-LOCKING CLOSURE PLATE FOR CARGO TANKERS I Fi led June 29, 1967 2 Sheets-Sheet 1 INVENTOR Irving L. Cigliano ATTORNEY July 30, 1968 l. L. CIGLIANO 3,394,834

SINGLE-LOCKING CLOSURE PLATE FOR CARGO TANKERS Filed June 29. 1967 2 Sheets-Sheet 2 FIG. 3.

INVENTOR Irving L, CigIiono BY 'M ATTORNEY Un ed m P ABSTRACT on THE DISCLOSURE fast-acting removable cover for closing an aperture inrthe steel deck -of.a cargo tanker, suchas an oil tanker, and securely locking the cover in place without any fastenings or other mechanical members being installed on the deck. A spider having preferably three or four legs,

clamps the underside of;the deck to the cover, which is on the topside of the deck, by operation of a single centrally located cam handle which is flush with the cover lid in the clamped position.

This invention relates to a closure plate for cargo tankers, of the same general type as shown in US. Patent No. 3,184,099 to Gravert. However, whereas the Gravert closure plate requires three separate cam latching operations to firmly lock the lid in place, the present cover plate is of simplified construction, and requires only a single latching operation to provide the same result.

Oil tankers and similar vessels having large below-deck tanks are commonly provided, in addition to a large covered aperture for access to the interior of each tank, with a number of smaller apertures, typically round holes about a foot or slightly more in diameter, through which buckets and tools may be lowered when necessary. The deck covers closing the smaller apertures are commonly known as Butterworth covers and have heretofore generally consisted of a gasketed cover plate vfastened to the deck by approximately a dozen bolts protruding from the deck for screwing the cover firmly to the deck by means of nuts. The above-mentioned Patent No. 3,184,099 shows an improved cover plate having three separate cam latching elements attached to the cover plate, each of which must be operated to firmly latch the cover plate in place. The possibility always exists that the person using the cover will forget to turn one or more of the three latching members, thus permitting the possibility of water leakage into the tank or fumes or deleterious vapors escaping from the tank. Furthermore, time is required to latch each of the three members individually, and where there are a number of these lids to be applied, this causes the operation to be both more expensive in labor, and to require a longer time, which may be very important in the case of a ship operating on a tight time schedule.

The improved cover plate of the present invention provides a gasketed cover plate which can be set down on the smooth deck so as to cover the aperture, and which has a spider, with three or four legs, on the underside, which spider is arranged to be clamped against the underside of the deck so as to firmly secure the cover plate in place, the clamping being accomplished by simply rotating a centrally-located cam handle on the upper side of the cover plate from a vertical position to a horizontal position where it is substantially flush with the top of the cover plate.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing, in which:

FIG. 1 is a view partly in section, taken on line 11 of FIG. 3, showing the cover plate in place, before the clamp is operated;

FIG. 2 is a view similar to FIG. 1, showing the same cover plate in place after the clamp has been operated and the cover plate is firmly secured; and

FIG. 3 is a top plan view of the cover plate as shown in FIG. 2.

Referring to FIGS. 1 and 2, a port-ion of the steel deck 2 of a tanker shown in section, the Butterworth hole being indicated at 3. The Butterworth cover of the invention is indicated generally at 4, and consists of a top plate 6 having a circumferential gasket 7 of any suitable gasket material, such that when the plate is firmly fastened to the deck, the cover is tightly sealed. Extending through the center of the cover plate is a shaft 8, which is slidable in but closely fitted to a central aperture in the plate 6 through which it extends. The shaft is preferably provided with suitable gasketing means as indicated at 9, to form as tight a seal as possible against egress of liquid or vapors or ingress of water through the central bore in the cover plate 6. Shaft 8 carries at its end a spider 11, having three legs as best shown in FIG. 3, although a different number, e.g. two or four legs, could also be used in a given case. The legs ar retained on the end of the shaft by any suitable means indicated as a pin 13, although any other retaining means, e.g. a nut arrangement on a threaded portion of the shaft, could also be used, and would have the advantage of being adjustable for different thicknesses of deck plates. Each leg 12 of the spider is preferably provided at the end thereof with a suitable pressure pad 14 for engaging the underside of the deck, both to insure adequate friction, and also to provide a certain amount of resilience. The other end of shaft 8 is provided with a pivot 16 on which is mounted cam handle 17 provided with a cam 18 of such configuration that when the cam handle 17 is in the vertical position shown in FIG. 1, the spider is downwardly displaced the maximum amount so as to provide a gap between gasket 7 and pads 14 sufficient so that the cover can easily be slid into place as shown in FIG. 1. A series of bosses 18, one of which is shown at the end of a reinforcing rib 19, extend down below the plane of gasket 7, to further aid in correctly positioning the cover in the aperture. Reinforcing ribs are not required for the other two bosses 18, since the handle receiving depression 21 provides adequate reinforcing for the cover on that side of the cover plate.

As shown in FIG. 2, when the handle 17 is moved to the horizontal position, the surface of cam 20 cooperates with the top of the cover plate so as to draw the spider toward the cover plate as seen in FIG. 2, and the dimensions are so arranged as to tightly clamp the cover plate in place on the deck. In order to remove the cover plate, the handle must, of course, be again raised to the vertical position, in which case the spider will return to the position of FIG. 1 by the force of gravity, or if desired, a spring can be provided about shaft 8 for this purpose.

It will be noted that when the cover plate is locked in place, the handle 17 is flush with the top surface of the cover plate due to being located in the recessed portion 21, so that the cover plate can be walked upon without providing any obstruction. The cam surface is so arranged that when the handle is in the position shown in FIG. 2, the resulting pressure between the spider and the plate 6 tends to keep the handle in this position, so that there is no tendency whatever for the handle to return to the vertical position shown in FIG. 1.

It will be seen that the above-described construction provides a very simple cover plate having only four major components, which nevertheless operate very effectively to provide the desired sealing action, with the minimum amount of obstruction, and requiring no additional components to be placed upon or fastened to the deck.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

I claim:

1. A closure for an orifice in a thick metal wall, comprising (a) a removable metal cover plate large enough to cover said orifice and having a continuous gasket on one side thereof for sealing the plate against said Wall, having a substantially centrally located aperture,

(b) a shaft extending through said aperture and axially slidable therein,

(c) liquid-and-vapor-tight sealing means between Said shaft and said plate, said sealing means permitting limited axial motion of the shaft,

((1) a spider mounted on said shaft, for axial motion therewith, on the gasketed side of the cover plate, said spider having at least two legs extending laterally for a sufficient distance to clamp the rim of said orifice between the ends of said legs and said cover plate,

(e) and mechanical force-multiplying means on th 4 other side of said plate from said gasket for axially sliding said shaft so as to draw said spider toward the cover plate and against the underside of said wall to clampingly compress said gasket and seal said plate against the metal wall.

2. The invention according to claim 1, said spider having three legs and a pressure pad at one end of each leg for engaging the underside of the wall.

3. The invention according to claim 1, said force multiplying means comprising manually operable cam means.

4. The invention according to claim 3, said cam means comprising a cam-operating handle extending away from said cover plate in the unclamped position of said spider, said handle lying flush with said cover plate in the clamped position of said spider.

5. The invention according to claim 4, said cover plate having a depression for receiving said handle in said flush position.

References Cited UNITED STATES PATENTS 1,194,080 8/1916 Schaam 220-25 1,526,263 2/ 1925 Wilson ..a 220-25 JAMES B. MARBERT, Primary Examiner.