US3219197A

US3219197A - Derricks for ships

Info

Publication number: US3219197A
Application number: US317710A
Authority: US
Inventors: Hallen Alf Eskil
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-11-09
Filing date: 1963-10-21
Publication date: 1965-11-23
Anticipated expiration: 1982-11-23
Also published as: NL300174A; ES293346A1; GB1039178A; FI42171B; DK115084B

Description

Nov. 23, 1965 A. E. HALLEN DERRICKS FOR SHIPS 4 Sheets-Sheet 1 Filed Oct. 21. 1963 Nov. 23, 1965 A. E. HALLEN DERRICKS FOR SHIPS Filed Oct. 21, 1963 4 Sheets-Sheet 2 Nov.23, 1965 v i ,E, HA| EN 3,219,197

DERRICKS FOR SHIPS Filed 001:. 21, 19s: 4 Sheets-Sheet s M W. If. f

Nov. 23, 1965 A. E. HALLEN I DERRICKS FOR SHIPS 4Sheets-Sheet 4 Filed 001;. 21, 1965 United States Patent 3,219,197 DERRICKS FOR SHIPS Alf Eskil Hallen, Odinsgatan 23, Goteborg, Sweden Filed Oct. 21, 1963, Ser. No. 317,710 Claims priority, application Sweden, Nov. 9, 1962, 12,056/ 62 7 Claims. (Cl. 212-3) This invention relates to the known topping lift arrangement in derrick for ships, wherein two topping lifts by means of swinging arms connect the free end of the derrick to separate points of a mast or the like which points are spaced apart in the athwartship direction, said arms being articulated to the mast and having a limited ability to swing such that if the derrick is swung outwards over one side of the ship the end of the arm connected to the topping lift and located nearest the other side of the ship is disposed in an athwartship plane which is so positioned relative to the derrick attachment that the derrick can be swung again inwards over the ship merely by shortening said topping lift. In such an arrangement the two topping lifts as viewed in a horizontal plane always make an angle with each other thereby securing a stable position of the derrick in all angular positions thereof.

In this previously known arrangement the arms are connected with the mast by means of a universal joint having abutment surfaces, which limit the swinging ability of the arms such that the arms cannot be swung below the horizontal plane through the joint nor can they be swung beyond a longitudinal plane of the ship through the joint. In certain positions of the derrick the arcs can be subjected to considerable moments, and for this reason, they must have large dimensions which also holds true of the universal joints. Consequently, the arms are comparatively heavy, and since they are placed at a relatively high level of the mast they are likely to have a certain influence on the stability of the ship.

In contrast thereto the arrangement according to the invention is substantially characterized in that the swinging ability of each arm is limited by two movable stays, one stay being adapted to limit the swinging movement of the arm about a substantially vertical axis and the other stay being adapted to limit the swinging movement of the arm about a substantially horizontal axis, the lengths of the stays being related such that the arms are substantially horizontal and extending longitudinally of the ship when both stays are loaded.

The invention is explained more closely hereinbelow with reference to embodiments thereof illustrated in the annexed drawings. FIGS. 1 to 3 are a front View, a top view and a lateral elevation respectively, of a mast of Y- type provided with an arrangement according to the invention. FIGS. 4 and are a front view and a top view, respectively, of a modified embodiment applied to a conventional simple mast having an athwartship outrigger, and FIG. 6 is a further modification suitable for heavy load.

Referring to FIGS. 1 to 3, reference numeral 1 denotes a ships mast of Y-type. At some distance from their ends the arms 2 and 3 of the mast are connected with each other by means of a cross beam 4 the ends of which are projecting to some extent outside the mast arms.

Two swinging

arms

5 and 6 are articulated to the cross beam 4 each swinging arm being connected to the cross beam in close proximity to a mast arm. In the drawing the articulations are denoted at 7. Each articulation comprises a hinge member which is mounted on the cross beam 4 and turnable about a vertical axis and carries a horizontal pin for the swinging arm. The articulations are not illustrated in detail in the drawing.

By means of flexible stays 8, 9 preferably steel cables,

3,219,197 Patented Nov. 23, 1965 the outer end of the arm 5 is connected to the end of the mast arm 2 and to the adjacent end of the cross beam 4, respectively. In the embodiment illustrated the length of the arm 5 and of the stays 8, 9 are related such that both stays are stretched when the arm 5 as illustrated is h0rizontal and extends longitudinally of the ship. In a corresponding manner two

stays

10 and 11 are provided for the arm 6. In the position of the arm 6 illustrated in the drawing the stay 10 only is stretched.

At the lower part of the mast 1 there is mounted in the usual manner a derrick 12 which in the drawing is swung outwards in a horizontal position and at right angles to the side of the ship. The derrick has two

topping lifts

13 and 14 which are both connected with the free end of the derrick 12. For the sake of clearness the topping lift 14 in FIG. 1 is illustrated spaced apart from the end of the derrick. For the topping lifts there are provided two winches the drums of which are denoted at 15 and 16.

One end portion of the topping lift 13 is wound onto the winch drum 15. Therefrom the to ping lift 13 passes over a leading block 18 on the mast arm 3 over a leading block 19 at the end of the arm 6 and then the topping lift extends down over a block sheave 20 at the outer end of the derrick and therefrom extends upwards to a block sheave 21 at the end of the arm 6 and down again to the end of the derrick where the other end of the topping lift 13 is fastened. In a corresponding manner one end part of the topping lift 14 is wound onto the winch drum 16 and passes therefrom over a leading block 23 at the mast arm 2, a leading block 24 at the end of the arm 5, a block sheave 25 at the end of the derrick (being shown spaced apart therefrom), over a block sheave 26 at the end of the arm 5 and down again to the end of the derrick where the other end of the topping lift is fastened.

In the arrangement described the derrick can be swung in a manner known per se in a horizontal plane by shortening one of the topping lifts and lengthening the other one, and the derrick can be swung in a vertical plane by shortening or lengthening both topping lifts at the same time. It will be apparent that during the swinging movement of the derrick the outer end of the derrick will move along a spherical surface, and by suitable operation of the

winches

15 and 16 it is possible to have the end of the derrick follow any desired path of the spherical surface.

Instead of fastening one end of each topping lift to the end of the derrick the topping lifts may be further extended such that each topping lift passes from one of the winch drums to the other one. In this case, the topping lifts are wound in opposite direction on one of the drums and are wound in the same directions on the other drum. In such an arrangement one of the winches is used for swinging the derrick in a horizontal plane and the other winch is used for swinging the derrick in a vertical plane.

This arrangement may be advantageous if hydraulic winches are used.

In FIG. 1 there is also shown a tackle 28 for the cargohook. The cargo fall 29 passes along the derrick 12 and via a leading block 30 mounted on the derrick up to a leading block 31 at the middle point of the cross beam 4 and therefrom down to a Winch 32 for the cargo fall.

In the position of the derrick 12 shown in FIGS. 1 to 3 the arm 5 is kept by the stays 8 and 9 in position such that the angle between the hopping lift 14 and the derrick is great enough to permit the derrick to be swung inwards again over the ship by shortening the topping lift 14. The tensile force acting on the topping lift 14 is taken by the stays 8 and 9 and the arm 5 is subjected to a compressive force. On the other side the arm 6 is substantially in alignment with the topping lift 13 and consequently takes the essential part of the tensile force exerted by said topping lift. A minor part only is taken by the stretched stay 10 whereas the stay 11 is completely releaved. The arm 6 can assume the illustrated oblique position due to the fact that the point of attachment of the stay 10 on the mast arm 3 is not located right above the articulation 7 but outside a longitudinal plane through said articulation.

From the drawing it will be seen that the movements of the swinging arms and 6 are limited by the stays 8, 9 and 1t 11 respectively. Considering the swinging arm 5 it will be apparent that the stay 8 determines how far the arm 5 can be swung downwards. In other words the stay 8 limits the swinging movement of the arm 5 about a horizontal axis. In a corresponding manner the stay 9 determines how far the arm 5 can be swung inwards toward the middle of the mast. Consequently the stay 9 limits the swinging movement of the arm about a vertical axis.

From the above it will be seen that the free end of the arm 5 can be moved over a spherical surface the radius of which is equal to the length of the arm. The arm is movable within a range limited by two circular arcs which intersect each other at the point represented by the position of the end of the arm shown in the drawing, said arcs being described when the arm from the position illustrated is moved downwards and outwards with stretched stay 8 and upwards with stretched stay 9, respectively.

As regards each of the

arms

5 and 6 it is to be noted that depending upon the position of the derrick 12 either one or the other of the stays or both stays are subjected to tensile forces, whereas the arm itself can be subjected to tensile forces or moderate compressive forces. It is consequently a matter of extraordinarily favour able load characteristics permitting a very simple and light construction of the whole system.

Assuming that the derrick 12 from the position illustrated is to be swung upwards by starting the winch drum 16 the arm 6 will always be in alignment with the topping lift 13 and both stays and 11 are releaved. The arm 5 on the other hand will remain in the position illustrated to begin with, but will eventually be swung upwards with stretched stay 9 and simultaneous releave of the stay 8. During this movement the free end of the arm 5 comes closer to the athwartship plane through the derrick. If the arm 5 were able to assume a vertical position or even to pass beyond said position it would be impossible thereafter to operate the derrick by means of the topping lifts. In order to prevent the occurrence of such a situation the top ends of the mast arms are provided with abutments 33 which come into contact with the

arms

5 and 6 when the derrick is topped.

In FIGS. 2 and 3 the chain-dotted lines indicate the positions of the various members when the derrick is lowered to horizontal position and extending longitudinally of the ship. FIG. 3 also shows in the same manner how the

arms

5, 6 bear on the abutments 33 when the derrick is maximally topped.

In the embodiment described the beam 4 must extend relatively far outside the articulations 7 for forming attachments for the

stays

9 and 11. In FIGS. 4 and 5 there is illustrated an embodiment having a smaller extension in the athwartship direction. This embodiment is shown as applied to a conventional simple mast 40 which carries an athwartship outrigger 41. The outrigger carries the swinging

arms

5 and 6. These figures also show the two flexible stays 8 and 10 which are secured to arms 42 projecting upwards from the upper side of the outrigger 41. These arms 42 also carry the abutments 33.

The flexible stays 9 and 11 of the preceding embodiment are here replaced by rigid stays or braces 43, 44 which at one end are articulated to the central part of the outrigger 41 and at the other end to slide 45 adapted to slide on the

arms

5 and 6, respectively. In the illustrated position of the derrick the stay 43 is subjected to compressive forces and the slide 45 bears on an abutment at the end of the arm 5. In contrast thereto the stay 44 is releaved.

Instead of a slide and brace of constant length a telescopically extensible brace may be used the extension of which may be limited. This brace is articulated to the end of the swinging arm and has a minimum length adapted to effect the desired guiding of the movement of the swinging arm.

In case of derricks for heavy loads, for instance to 200 tons, it may be unnecessary to load the swinging arms with the full tensile forces acting on the topping lifts. FIG. 6 is a diagrammatic view of an arrangement in which the swinging arms are partially releaved.

From a comparison between FIGS. 2 and 6 it will be seen that each of the topping lifts 13 and 14 according to FIG. 2 which topping lift in practical service usually consist of tackles, is divided into two parts in the construction according to FIG. 6. In the embodiment exemplified, three runs 14' of the tackle are passing between the head of the derrick 12 and the swinging arm 5, one of these runs passing downwards to a winch not shown. Two runs 14" are passing between the head of the derrick and a point on the cross beam 4 midway between the swinging

arms

5 and 6. In a similar manner, the topping lift 13 is divided into two parts, one part 13' only being shown in FIG. 6.

The subdivision of the topping lifts results not only in a releave of the swing arms, but also in a more rapid operation, since during the swinging movement of the derrick 12 in a horizontal plane the topping lift parts 13' and 14' only are lengthened and shortened respectively, whereas the lengths of the

topping lift parts

13 and 14" are not materially changed. However, when the derrick is lifted or lowered all of the topping lift parts are taking part in the operation.

If the derrick is used for lighter loads the blocks connected to the cross beam 4 may be detached from the beam and attached to a point near the lower end of the derrick with the result that even the topping lift parts 13" and 14" will not be materially changed as to their lengths during lifting and lowering of the derrick. In this case the topping lift parts 13" and 14" are not operating and all operations are carried out merely by means of the topping lift parts 13' and 14' resulting in an increased speed of operation.

In the embodiment exemplified the lengths of the stays are related such that the swinging arms are extending exactly horizontally and longitudinally of the ship when both stays are loaded. Since the function of the swinging arms is to keep one topping lift attachment at a distance from an athwartship plane through the derrick attachment when the derrick is swung outwards, it will be obvious that said extension corresponding to the direction of the swinging arm 5 according to the drawing is not of decisive importance, and deviations therefrom are possible within the scope of the invention. The invention may also be applied in cases where instead of a mast having an athwartship outrigger or an Y-mast or X-mast there are provided two derrick poles standing at a distance from each other in the athwartship direction. The swinging arms may also be secured to a wall of an upper structure of the ship.

What is claimed is:

1. A topping lift arrangement for a derrick for a ship, which comprises a mast;

a derrick member pivotably attached at one end thereof to said mast;

two topping lifts;

two swinging arms articulated to the mast;

means including block sheaves on said swinging arms for guiding said topping lifts over the ends of said arms;

said topping lifts connecting the free end of the derrick to separate points on the mast with the aid of said swinging arms;

said points being spaced apart in the athwartship direction;

a first movable stay extending between the mast and each swinging arm for limiting swinging movements of said arm about a substantially vertical axis;

a second movable stay extending between the mast and each swinging arm for limiting swinging movements of said arm about a substantially horizontal axis;

the lengths of said first and second stays being related such that each said arm is substantially horizontal and extending longitudinally of the ship when both associated stays are loaded so that when the derrick is swung outwards over one side of the ship the end of the arm connected to the topping lift located nearest the other side of the ship is disposed in an athwartship plane so positioned relative to the derrick attachment that the derrick can be swung again inwards over the ship merely by shortening said topping lift.

2. Arrangement according to claim 1, characterized in that one of the stays is secured to the mast above the articulation point of the arm, whereas the other stay is secured to the mast substantially on a level with the articulation point but at a distance therefrom in the athwartship direction.

3. An arrangement according to claim 2, characterized in that the attachment of the first named stays as viewed from the derrick attachment is located somewhat beyond the longitudinal plane of the ship through the articulation point of the arm.

4. An arrangement according to claim 1, characterized in that both stays are flexible.

5. An arrangement according to claim 1, characterized in that one stay is flexible and the other one is rigid, the rigid stay consisting of a telescopically extensible brace articulated to the end of the swinging arm and having a minimum length adapted to effect the desired guiding of the movement of the swinging arm.

6. An arrangement according to claim 1, characterized in that each arm is mounted on a horizontal pin of a hinge member which is connected with the mast and swingable about a vertical pivot pin.

7. An arrangement according to claim 1, characterized in that each topping lift consists of a two-part tackle, one part of which connects the head of the derrick with the swinging arm and the other part of which connects the head of the derrick with a fixed point on the mast.

References Cited by the Examiner UNITED STATES PATENTS 2,782,938 2/1957 Mege 2123 2,914,193 11/1959 Kohnenkamp et al 2l2-3 3,076,560 2/1963 Bushong et al 21259 3,090,493 5/1963 Landtman 2l23 FOREIGN PATENTS 906,255 9/ 1962 Great Britain.

SAMUEL F. COLEMAN, Primary Examiner.

Claims

1. A TOPPING LIFT ARRANGEMENT FOR A DERRICK FOR A SHIP, WHICH COMPRISES A MAST; A DERRICK MEMBER PIVOTABLY ATTACHED AT ONE END THEREOF TO SAID MAST; TWO TOPPING LIFTS; TWO SWINGING ARMS ARTICULATED TO THE MAST; MEANS INCLUDING BLOCK SHEAVES ON SAID SWINGING ARMS FOR GUIDING SAID TOPPING LIFTS OVER THE ENDS OF SAID ARMS; SAID TOPPING LIFTS CONNECTING THE FREE END OF THE DERRICK TO SEPARATE POINTS ON THE MAST WITH THE AID OF SAID SWINGING ARMS; SAID POINTS BEING SPACED APART IN THE ATHWARTSHIP DIRECTION; A FIRST MOVABLE STAY EXTENDING BETWEEN THE MAST AND EACH SWINGING ARM FOR LIMITING SWINGING MOVEMENTS OF SAID ARM ABOUT A SUBSTANTIALLY VERTICAL AXIS; A SECOND MOVABLE STAY EXTENDING BETWEEN THE MAST AND