GB1601259A

GB1601259A - Hatch cover for ships

Info

Publication number: GB1601259A
Application number: GB2531578A
Authority: GB
Original assignee: Mac Gregor International SA
Current assignee: Mac Gregor International SA
Priority date: 1978-02-03
Filing date: 1978-05-31
Publication date: 1981-10-28
Also published as: DE2804650C3; DE2804650B2; DD140235A5; DE2804650A1

Description

(54) A HATCH COVER FOR SHIPS (71) We, MACGREGOR INTERNATIONAL S.A., a Body Corporate organized under the laws of Switzerland, of St. Jakobs-strasse 9, 4002 Basel, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to ships having a hatch cover arrangement with at least one hatch cover, functioning also as a beam, which can be fixed between the longitudinal sills of the hatch coaming fixing means lying outside the hatch so that transverse forces can be transmitted by the hatch cover.

Known hatch covers of this type can be clamped on both sides by means of wedges against the hatch sill and can be clamped against the longitudinal bracing of the ship via appropriate reinforced points. The wedges can be displaced either horizontally or vertically and can only transmit pressure forces counteracting any tendency of the sides of the ship to fall inwards when there is external loading on the body of the ship.

Containers are being carried increasingly as deck freight on top of ship's hatch covers.

These containers are "stopped" on the hatch covers by means of appropriate stoppers. The containers carried as deck freight are stacked on top of each other up to three containers high. Considerable dynamic transverse forces are created by the containers on the cove.

during a voyage. With long hatches which have dimensions of up to 3/4 of the length of the ship in the case of small and medium freight ships, particularly in special ships, considerable deformation forces are introduced into the structure of the ship by the loaded hatch covers and these forces can lead to considerable falling in or falling out of the longitudinal sills of the hatch. The forces which bring about falling outwards of one side sill are not transmitted by known hatch covers to the opposite side sill and thus to the opposite side of the ship.

In order to solve this problem, hatch covers having high webs on the underside of the cover are known, the ends of which webs can be connected to the inside of the sill pins guided transverse to the cover. These hatch covers can in fact transmit tension forces. But they can only be released from the underside of the cover and release of the fixing pins is difficult under strain The invention seeks to improve a hatch cover of the type acting as a beam so that both compression forces and tension forces can be transmitted simply from one side of the ship to the other and it can be ensured that the hatch cover can be easily released under maximum strain.

According to the invention there is provided a ship having a hatch cover arrangement comprising a beam hatch cover member for attachment to longitudinal sills of a hatch upwards open stop plates associated with the sills, stop bars on the hatch beam cover member for insertion into the upwardly open stop plates and two stop members carried by each stop bar at a spacing from each other related to the thickness of the stop plates, the stop members being adjustable axially of the stop bar on at least one longitudinal side of the beam hatch cover.

Preferably the stop are generally annular.

The adjustable stop members may be constructed as nuts which are adjustable on threaded sections of the stop bars. For enabling relief of the adjustable nuts, stops may be arranged at the hatch cover and sill edge for applying pressure cylinders acting transversely to the longitudinally sill.'hatch sill. has two Preferably each beam pairs of stop bars which are arranged preferably in the region of the transverse edges of the hatch cover and spaced longitudinally with respect to each other.

The invention is illustrated by way of example in the drawings and described below in detail together with the drawings.

Fig. 1 shows a plan view of a hatch cover in accordance with the invention.

Fig. 2 shows a view along the line IIII of Fig. 1; Fig. 3 shows a side view of a stop plate fixed to the hatch sill, and Fig. 4 shows a view along the line IVIV of Fig. 1* Fig. 1 shows a portion of a hatch whose length can be equal to more than 75% of the length of the ship. The longitudinal sills of the hatch can move apart both in different loading condition in the harbour and under dynamic loading of the ship during the voyage and with a deck load and this movement can amount to up to 100 mm.

In order to achieve sufficient rigidity of the hall structure of the ship during the voyage, i.e. under dynamic loading, certain of the hatch covers are constructed to act as beams i.e. covers whose construction and fastening enable transverse forces can be transmitted from one side of the ship to the other side of the ship. These covers will hereinafter be refcrred to as beam hatch covers. In Fig. 1 a hatch cover 2 of this type is shown in plan view. Normal covers 4 and 6 are attached on both sides respectively to the beam hatch cover. In the embodiment shown, the cover 2 is of pontoon type, i.e. one which is raised away from the hatch with a loading gear or placed on to the hatch with a loading gear.

The hatch beam cover 2 is provided with reinforcements in the region of its two transverse edges 8 and 10 by means of which reinforcements the tension and compression forces arising during operation can be transmited from one side of the ship to the other.

These reinforcements can be constructed as tubular or box-shaped structures in the hatch cover. In order to be able to transmit the tension and compression forces stops are provided, i.e. stops 12 which are rigid on one longitudinal side and stops 14 which are adjustable on the other longitudinal side.

Furthermore pins 16 are provided on the longitudinal sides of the cover and these cooperate with fixed guides 18. The hatch cover is further provided with lashing devices 20.

Stop bars 22, 24 respectively are provided, as can be seen in detail from Figs. 2 and 4, for the purpose of transmitting the tension and compression forces on the ends of the reinforced structures of the hatch beam cover 2.

Stop plates 28, 30 are provided on the edge 26 of the sill these plates extending parallel to the longitudinal edges 32, 34 of the cover 2 and being provided with portions 36 which are open on the top into which the stop bars 22, 24 engage. The portions are provided therefore with guide portions 38. The depth of the portions can be selected so as to be larger than the diameter of the stop bars. It can however also be equal to this diameter or possibly even smaller.

Stops are provided in each case on the stop bars at a spacing and are constructed preferably in annular shape. The stops I2 are constructed as rings or plates 40 on one side of the hatch beam cover 2, which rings or plates 40 are fixed to the stop bar 24 and in fact at a spacing a which is slightly larger than the thickness b of the stop plate 30. The cover is therefore fixed transverse to the hatch by means of stops 12. A guide wedge 41 fixed to the edge of the stop bar 24 cooperates with the guide portion 38 of the stop plate 30 and with a thwartships (transverse to the ship) acting guide 42. The stop 14 having two stops adjustable crosswise to the hatch is provided on the opposite longitudinal side of the hatch beam cover 2.Nuts 44 are provided as these stops and are adjustable on threaded portions 46 between which a smooth portion 48 lies having a length which is the result of adding the maximum fall in and fall out under different loading conditions. A stop 50 is provided at the end of the stop bar 22. A jaw key is used on the inside of the stop plate 28 for the purpose of actuating the nuts 44 while a jaw key can be used optionally or a plug key on the outside. A jaw key 52 and a plug key 54 are indicated in broken lines in the drawing.

A bearing 56 may be provided for the plug key.

In order to use the hatch beam cover 2 the nuts 44 are rotated back into their final position so that when fitting the cover into the fixed stop 12 the stop bar 22 can be inserted with its middle portion 48 and independently of the size of the fall in or fall out of the wall of the ship and thus of the sill, into the open recess of the stop plate 28. The nuts are then rotated on to the stop plate and tensioned with the key against the stop plate. The hatch beam cover can thus transmit tension and compression forces between the stops plates 28 and 30.

Locking can be introduced therefore by means of the nuts 44 to the respective actual condition of the fall in or fallout of the longitudinal sills and can be locked in this position. On a voyage or the like, changes in the load of the clamping points can occur combined with loading of the locking screws which can therefore reach a magnitude of several hundred tonnes. Under these load its is not possible to release a nut while it is under load.In order to arrive at release facilitating release of the nut which is under load as can be seen from Fig. 2 a pressure cylinder 58 is provided between the longitudinal edge 34 of the hatch beam cover 2 or a structure of the cover reinforcement which is mounted in front of it and the stop plate 28 and this pressure cylinder have an installation length which is shorter than the spacing between the bearing surface 60 of the cylinder on the longitudinal side of the cover 2 and the bordering side of the stop plate 28 taking into account the maximum tendency to fall inwards. Thus a single cylinder can be provided but two cylinders at a spacing adjacent each other are preferably arranged. These cylinders can be fixed to the cover 2. However it is also possible to mount these cylinders in each case only if necessary for example to place the cylinders on to a mounting 62 which is provided with a basin-shaped recess for the cylinders. By moving the piston of the cylinder 58 in an outward direction and building up the compression force between the cover and the stop plate 28 the nut 44 which is assumed as being under load is relieved and can be rotated then with the aid of the key 52 and be brought out of engagement with the stop plate 28.

The nut which is opposite the nut under load in each case can be released readily with the aid of keys.

Accordingly the externally arranged nut 44 can be relieved if it is under load from forces counteracting an increase in the tendency to fall in an outward direction. The relief cylinder ought in this case to be supported by its end facing the cover against a fixed stop on the edge of the sill and by its outer end against a structure connected to the cover so that the cover would be set towards the right under strain when the cylinder in Fig.

2 was moved outwards.

Owing to the construction and fixing of the hatch beam covers in accordance with the invention the latter are fixed longitudinally of the ship in the stop plates at the same time.

Since the hatch beam covers respectively are clamped at their front and rear ends against the sill diagonal forces can be transmitted too via the covers, whereby the covers if necessary can be provided with appropriate diagonally acting static structures.

The hatch cover 2 is mounted on sliding element 64 arranged in the edge of the sill as are the remaining hatch covers and in fact it is mounted on the underside of the flange of the cover by means of appropriate bearing areas 66.

The seal 68 on the longitudinal side 34 of the cover 2 having a settable locking position 14 has such a width that over the entire range of the change in width of the hatch sealing engagement with the sealing rib fixed to the sill rail 70 is ensure by the tendency of the hatch sill to fall in an inward or outward direction. In contrast to this the seal has a small width on the other longitudinal side 32 of the cover with the rigid locking point 12 since the cover on this side always takes up the same position relative to the longitudinal sill.

WHAT WE CLAIM IS:- 1. A ship having an hatch cover arrangement comprising a beam hatch cover member for attachment to longitudinal sills of a hatch upwardly open stop plates associated with the sills, stop bars on the hatch beam cover member for insertion into the upwardly open stop plates and two stop members carried by each stop bar at a spacing from each other related to the thickness of the stop plates, the stop members being adjustable axially of the stop bar on at least one longitudinal side of the beam hatch cover.

2. A ship according to Claim 1, wherein the stop members are generally of annular shape.

3. A ship according to Claim 1, wherein the adjustable stop members are formed as nuts which are adjustable on thread sections of stop bars.

4. A ship according to Claim 3, wherein, for enabling relief of the adjustable nuts, stops are arranged at the hatch cover and sill edge for applying pressure cylinders acting transversely to the longitudinal sill.

5. A ship according to Claim 1, wherein the beam hatch cover members are each provided with clamping means in the region of their transverse edges for attachment to adjacent covers.

6. A ship according to Claim 5, wherein the hatch covers are each provided with reinforcements adjacent to their transverse edges for transfer of forces from one side to the other.

7. A ship according to any one of the preceding Claims, wherein the hatch covers are provided with broader seals at the side on which they are equipped with the adjustable stop means.

8. A ship having a hatch cover arrangement substantially as described herein with reference to the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

basin-shaped recess for the cylinders. By moving the piston of the cylinder 58 in an outward direction and building up the compression force between the cover and the stop plate 28 the nut 44 which is assumed as being under load is relieved and can be rotated then with the aid of the key 52 and be brought out of engagement with the stop plate 28.

The nut which is opposite the nut under load in each case can be released readily with the aid of keys.

Accordingly the externally arranged nut 44 can be relieved if it is under load from forces counteracting an increase in the tendency to fall in an outward direction. The relief cylinder ought in this case to be supported by its end facing the cover against a fixed stop on the edge of the sill and by its outer end against a structure connected to the cover so that the cover would be set towards the right under strain when the cylinder in Fig.

2 was moved outwards.

Owing to the construction and fixing of the hatch beam covers in accordance with the invention the latter are fixed longitudinally of the ship in the stop plates at the same time.

Since the hatch beam covers respectively are clamped at their front and rear ends against the sill diagonal forces can be transmitted too via the covers, whereby the covers if necessary can be provided with appropriate diagonally acting static structures.

The hatch cover 2 is mounted on sliding element 64 arranged in the edge of the sill as are the remaining hatch covers and in fact it is mounted on the underside of the flange of the cover by means of appropriate bearing areas 66.

The seal 68 on the longitudinal side 34 of the cover 2 having a settable locking position

14 has such a width that over the entire range of the change in width of the hatch sealing engagement with the sealing rib fixed to the sill rail 70 is ensure by the tendency of the hatch sill to fall in an inward or outward direction. In contrast to this the seal has a small width on the other longitudinal side 32 of the cover with the rigid locking point 12 since the cover on this side always takes up the same position relative to the longitudinal sill.

WHAT WE CLAIM IS:- 1. A ship having an hatch cover arrangement comprising a beam hatch cover member for attachment to longitudinal sills of a hatch upwardly open stop plates associated with the sills, stop bars on the hatch beam cover member for insertion into the upwardly open stop plates and two stop members carried by each stop bar at a spacing from each other related to the thickness of the stop plates, the stop members being adjustable axially of the stop bar on at least one longitudinal side of the beam hatch cover.
2. A ship according to Claim 1, wherein the stop members are generally of annular shape.
3. A ship according to Claim 1, wherein the adjustable stop members are formed as nuts which are adjustable on thread sections of stop bars.
4. A ship according to Claim 3, wherein, for enabling relief of the adjustable nuts, stops are arranged at the hatch cover and sill edge for applying pressure cylinders acting transversely to the longitudinal sill.
5. A ship according to Claim 1, wherein the beam hatch cover members are each provided with clamping means in the region of their transverse edges for attachment to adjacent covers.
6. A ship according to Claim 5, wherein the hatch covers are each provided with reinforcements adjacent to their transverse edges for transfer of forces from one side to the other.
7. A ship according to any one of the preceding Claims, wherein the hatch covers are provided with broader seals at the side on which they are equipped with the adjustable stop means.
8. A ship having a hatch cover arrangement substantially as described herein with reference to the drawings.