WO1989005755A1

WO1989005755A1 - Apparatus for controlled lowering or moving of a suspended load

Info

Publication number: WO1989005755A1
Application number: PCT/NO1987/000084
Authority: WO
Inventors: Roald ØEN
Original assignee: Harding Safety A/S
Priority date: 1987-12-18
Filing date: 1987-12-18
Publication date: 1989-06-29

Abstract

Apparatus for controlled lowering or moving of a suspended load, in particular a lifeboat in a davit, from a position near a ship's side or the like to a launching position, comprising a flexible element (1) extending in two or more portions (folds) (1A, 1B, 1C, 1D) between two end pieces (11, 12) which in turn are connected to tension transfer members. This partly corresponds in principle to a single or multiple block and tackle arrangement. The distance (D) between the end pieces (11, 12) capable of being increased in a controlled manner under the influence of tensional forces due to the load. The flexible element has the form of a belt (1), and at least one of the end pieces (11, 12) is provided with one or more transverse bolt(s) (2A, 2B, 4), about which the belt is wound in a substantially U-shape and is designed to slide round in its longitudinal direction. A manual braking device (5) presses two portions (folds) of the belt (1C, 1D) against each other at a place where these move in mutually opposite directions under the controlled lowering or movement in order to bring about a braking effect.

Description

APPARATUS FOR CONTROLLED LOWERING OR MOVING OF A SUSPENDED LOAD

This invention relates to an apparatus for controlled lowering or movement of a suspended load, in particular a lifeboat in a davit, from a position near a ship's side or the like to a launching position.

In many types of lifeboat arrangements with davits on ships there is a need for specific auxiliary means (English: "bowsing gear") for manoeuvering the lifeboats in relation to the ship's side so that the lifeboat in a position relatively close to the ship's side can be boarded by crew and passengers, in order thereafter to be moved further out from the ship's side with subsequent launching down to the sea surface. This can be a rather hazardous operation under difficult conditions, in particular when the ship has a list. This situation is illustrated more closely in fig. 1 of the drawings.

Until now there has usually been employed an arrange¬ ment with blocks and tackle and conventional ropes as means for carrying out the above operation, whereby control of the lateral lifeboat movement was provided for by manual force directly at the free end of the tackle rope. The manoeuver¬ ing with such conventional equipment is often very critical and heavy, particularly with modern, large lifeboats. Besides the tackle equipment itself is relatively cumbersome and requires much space.

In the principle this invention can also be considered to start out from something having resemblance to a trad¬ itional tackle arrangement, but is based on several novel and specific design features and elements.

More closely defined the apparatus according to the invention comprises a flexible element extending with two or more portions (folds) between two end pieces which in turn are connected to tension transfer members, corresponding somewhat to a single or multiple tackle arrangement, the distance between the end pieces being adapted to be increas¬ ed in a controlled manner under the influence of tensional forces due to the load.

What is novel and specific in the apparatus according to the invention in the first place consists therein that the flexible element is provided in the form of a belt, that at least one of the end pieces is provided with at least one transverse bolt about which the belt is trained in a substantially U-shape and is adapted to slide around the bolt(s) in its longitudinal direction, and that brake means serve to press two belt portions against each other at a location where these move in mutually opposite directions under the controlled lowering or moving, in order to bring about a braking effect.

With the solution given herein there- is obtained a safe and comfortable operation under the particular form of lifeboat manoeuvering at the same time as the function is reliable under the most difficult conditions. Moreover the apparatus according to the invention may be manufactured to relatively small dimensions and a low weight.

Even though the invention primarily is intended for use in lifeboat operations as explained above, it is not to be excluded that also other fields of use will be of interest, where there is a question of a corresponding controlled lowering or movement of a suspended load or the like.

In the following description the invention shall be explained more closely with reference to the drawings, in which:

Fig. 1 illustrates the particular situation under lifeboat launching, which requires an auxiliary means for lateral movement of a lifeboat suspended from a davit,

Fig. 2 shows in perspective view an example of an embodiement of the apparatus according to the invention, Fig. 3 shows the apparatus of fig. 2 in longitudinal .section and

Fig. 4 shows the apparatus of fig. 2 in a certain practical situation of use.

In fig. 1 there is partially shown a ship with a ship's side 25 having a significant list, and on the ship's deck there is shown a davit 27 with a suspended lifeboat in two positions A and B respectively. In such a situation with a list the lifeboat must be kept close to the ship's side (position A) in order to be boarded by crew and passengers.

Auxiliary means 20 ("bowsing") attached to the lifeboat at 21 together with a wire length 22 connected to the main arm 28 of the davit at a suitable point, serves to keep the lifeboat in the desired position A, in which the actual hoisting wire 23 for launching the lifeboat from the davit 27 extends at an inclination inwards from the outer end of the davit. Thus, in this position the connection 20 - 22 is subjected to a significant tensional force.

The necessary lateral movement of the lifeboat from position A to postion B in order to make possible launching from the latter position down to the sea surface 29, must take place under safe control, which implies that the means 20 should have a form of braking effect at the same time as it allows for an increase of the distance between a point of suspension at 21 on the lifeboat and the attachment points for the wire 22 at the davit arm 28.

In an advantageous manner an apparatus according to the invention as shown in fig. 2, can carry out the function which according to the above explanation shall be provided for by the unit 20 in fig. 1. At its respective ends the apparatus in fig. 2 has anchoring holes 11A and 12A intended for connection to the lifeboat, as shown at 21 in fig. 1, and to a davit or the like through a wire^*~22 as also shown in fig. 1. These anchoring holes 11A and 12A are located in respective anchoring plates being included in end pieces 11 and 12 with associated side plates 11B, 11C and 12B, 12 C respectively, as essential structural parts of these end pieces. Between both end pieces 11 and 12 there is extended a flexible element in the form of a strong belt 1 which constitutes a supporting sling having sufficient strength to stand up to stresses which may occur, as mentioned above in connection with position A shown for the lifeboat in fig. 1. As will be seen in fig. 2 the belt 1 runs back and forth so as to form several portions (folds) 1A, IB, 1C and ID between the end pieces. Thus, one end of the belt is anchored to an attachment bolt 3 between the two sides 11B, 11C of the end piece 11 and extends in the form of belt portion ID to a transverse bolt 2A in the end piece 12, wherein the belt through a U-shaped bight returns back through a belt portion 1A to the end piece 11 and then about a second bolt 4 having a somewhat larger diameter than the bolt 2A.

From the bolt 4 belt portion 1C again crosses over to end piece 12 and about a second transvers bolt therein in order to finally return to end piece 11 through belt portion ID which together with belt portion 1C passes between the bolt 4 and a clamping member in the form of an eccentrically journaled roller 15, with a free end 10 of the belt 1 extended to a reel 7 having a slit 7C through which the end of the belt is passed. Normally the reeling roller 7 is not intended to take up any significant forces when the appara¬ tus is used.

The length of the transverse bolts 2A, 2B and 4 between the side walls of the end pieces 11 and 12 is approximately equal to the width of the belt 1, so that this is suitably guided in its course back and forth between the end pieces. The choice of material for and possible surface treatment of the bolts and for the belt 1 can be so determined that the belt can slide with a suitable friction in the U-shape mentioned around the respective bolts so that there is provided for a contribution in the form of friction braking which makes it more easy to control the apparatus under manoeuvering as explained previously, in particular when heavy loads or large lifeboats are to be handled. This frictional effect at the transverse bolts is based on the necessary prerequisite that these are not rotatable. In specific cases, however, it may possibly be practical to design these bolts for rotation in order to obtain a reduced friction, for example for the purpose of being able to employ the apparatus for lifting a load, that is with a function like block and tackle.

Certain features of the apparatus in fig. 2 appear somewhat more clearly from the longitudinal section in fig. 3, wherein among other thing arrows indicate how the various belt portions move in opposite directions during a controll¬ ed lowering or displacement movement so that the mutual distance between the end pieces 11 and 12 increases. During this operation the so called free end 10 of the belt 1 should be able to be reeled freely out from the reel 7, so that belt portion ID can move towards the left (as indicated with an arrow) in fig. 3. This figure shows the belt fully reeled out from reel 7, so that this roller is empty. In other words the situation shown in fig. 3 can be regarded as a maximum extended position of the apparatus.

In contrast thereto fig.4 shows the apparatus in an almost fully retracted position, where a significant amount 10A of the belt 1 is shown wound on to the reel 7, which is here visible only in the form of a stud 7B having a cross- section adapted for cooperation with a crank-handle or the like.

Considering now again figs. 2 and 3, as a substantial component in the apparatus there is included a brake device 5 which acts to press the two belt portions 1C and ID against each other between the bolt 4 and-said roller 15 which belongs to the brake device 5. As already mentioned the clamped belt portions 1C and ID at this location will move in opposite directions during operation. Therefor the belt itself constitutes the friction element or brake lining which provides for the braking effect, and this in a very favourable manner since the oppositely directed longitudinal movements of the clamped belt portions all the time will bring new parts of the belt to give a braking effect. Thereby local heating and unfavourably concentrated wear is avoided. Accordingly the belt 1 has a double function: in the first place it is a load carrying element and in the second place it has a function as a brake element.

The above mentioned clamping effect, in order to provide for braking kan be obtained in many ways, and in the example shown the eccentric roller 15 which is journaled on a trunnion 14 carried by an arm 13, is adjusted by means of a screw 8 having a hand wheel 6 and a slide nut 9 being threadedly engaged with the screw 8 thereby to vary the angular position of the arm 13. With a suitable adjustment of the eccentricity of the roller 15 and the other relative geometrical relationships, the brake device 5 can be so designed that it has a self-increasing braking effect obtained thereby that the longitudinal movements of belt portion ID through the clamping location positively contri¬ butes to increase the clamping force between roller 15 and bolt 4.

An advantageous practical detail with respect to the brake device consists therein that the screw 8 with hand wheel 6 is arranged to be displaceable with a limitation in the longitudinal direction of the screw, by means of a holding member 17 mounted at a right angle to an extension 11D of the side plate lie Between the holding member 17 and the handwheel 6 there is mounted a compression spring 18 seeking to urge the hand wheel with screw 8 to the right in fig. 3, which through the intermediary of arm 13 keeps the roller 15 in its braking poisition. A flange 16 serves to delimit the longitudinal movement of screw 8.

A practical advantage obtained with this design is that it will be easy to pull a slack and to collect the free belt end 10 on reel 7 when the belt 1 is unloaded, as the spring 18 will permit the brake roller 15 to be removed from its engagement with the belt portions between this roller and bolt 4, when the belt end 10 is pulled towards the right in fig. 3. The side plate 11C with its extension 11D is partially cut away in fig. 2 in order to show parts of the brake device 5.

A specific possibility which may be of interest in some cases is to let two of the above transverse bolts, for example bolts 2A and 2B be mutually moveable so that one can be pressed against the other with two belt portions between them, these belt portions having oppositely directed longitudinal movement under operation, which can be provided for by suitably guiding the belt portions. This will eliminate the need for a particular clamping member, such as roller 15.

In the example shown the anchoring of the belt at 3, the free end 10 of the belt and the brake device 5 are arranged at the same end piece 11. This is the end piece which is intended for direct connection to the lifeboat, as previously mentioned, and it is then an advantage to have the brake hand wheel 6 and also the reel 7 easily accessable from the lifeboat for manual operation during launching. Depending on the circumstances cases may be thought of however, in which these members and elements can be divided in other manners between the two end pieces 11 and 12. Specifically it may be of interest to locate the anchoring of the belt 1, i.e. the attachment bolt 3, on the other end piece 12 when there are involved a different number of portions than the four belt portions 1A, IB, 1C and ID as illustrated in figs. 2 and 3. As the simplest case the apparatus may be based on a similar principle as a single block and tackle, and in such case both the anchoring and the free end of the belt 1 necessarily must be located on the same end piece. For the purpose of carrying large loads the running of the belt between the end pieces can be multiple, perhaps with six portions as a practical maximum.

Certain features appearing from fig. 4 are already mentioned above, but in addition thereto there are some further components shown in fig. 4, which illustrates the practical use of the apparatus. By means of a shackle 42 the end piece 12 is connected to the wire 22 which is also shown in fig. 1. The arrow 22A indicates the tensional force to be transferred. At the opposite side a hook 41 of suitable type is inserted in the anchoring hole in the end piece 11. With shackles 44 there is indicated a connection to suspension means on a lifeboat, whereby the arrow 21A can be considered to represent the tensional force in the apparatus ^"due to the lifeboat, this force being of the same magnitude as, and directed oppositely to, the force 22A in wire 22. There is also shown a handle 45 which through a shackle 43 is connected to hook 41.

For the manual operation of the brake device 5 there may be thought of various other means than the handwheel 6 shown, e.g. a stick or the like.

The eccentric roller 15 which serves to give the clamping effect in the brake device 5 can also take other forms, but it is obvious that the surface part of such a clamping member which cooperates with an opposing surface of engagement, such as a transverse bolt 4, must have a rounded and smooth shape so that the belt 1 at this location will have a suitable run and is not subjected to damage during braking.

Claims

C l a i m s

1. Apparatus for controlled lowering or moving of a suspended load, in particular a lifeboat in a davit, from a position near a ship's side or the like to a launching position, comprising a flexible element (1) extending with two or more portions (folds) (1A, IB, 1C, ID) between two end pieces (11, 12) which in turn are connected to tension transfer members (21, 22), corresponding somewhat to a single or multiple tackle arrangement, the distance (D) between the end pieces (11, 12) being adapted to be increa¬ sed in a controlled manner under the influence of tensional forces due to the load, c h a r a c t e r i z e d in that the flexible element is provided in the form of a belt (1), that at least one of the end pieces (11, 12) is provided with at least one transverse bolt (2A, 2B, 4) about which the belt is trained in a substantially U-shape and is adapted to slide around the bolt(s) in its longitudinal direction, and that brake means (5) serve to press two belt portions (1C, ID) against each other at a location where these move in mutually opposite directions under the controlled lowering or movement, in order to bring about a braking effect.

2. Apparatus according to claim 1, c h a r a c t e r i z e d in that the transverse bolt(s) (2A, 2B, 4) has (have) a lenght corresponding to the width of the belt (1) .

3. Apparatus according to claim 1 and 2, c h a r a c t e r i z e d in that the transverse bolt(s) (2A, 2B, 4) are non-rotatable and thereby contribute to frictional braking of the belt during lowering or moving.

4. Apparatus according to claim 1, 2 or 3, c h a r a c t e r i z e d in that the brake device (5) co¬ operates with a transverse bolt (4) in order to provide for the braking effect.

5. Apparatus according to claim 4, c h a r a c t e r i z e d in that the brake device (5) comprises an eccentricaly journaled roller (15) adapted to press said belt portions (1C, ID) together against said transverse bolt (4) .

6. Apparatus according to claim 5, c h a r a c t e r i z e d in that the brake device (5) has a self-increasing braking effect caused by that belt portion (ID) against which the eccentric roller (15) is engaged.

7. Apparatus according to claim 1, 2 or 3, c h a r a c t e r i z e d in that the braking effect is provided for by means of two of said transverse bolts, one of these being adapted to be pressed against the other bolt and with two oppositely moving belt portions lying between said two transverse bolts.

8. Apparatus according to any one of the preceeding claims, c h a r a c t e r i z e d in that the brake device (5) is arranged on the same end piece (11) at which the free end (10) of the belt (1) is located.

9. Apparatus according to claim 8, c h a r a c t e r i z e d in that in the princple it is arranged as a twofold block and tackle having two transverse bolts (2A, 2B) on one end piece (12) which^""is not said same end piece (11), and that an end of the belt (1) is anchored in said same end piece (11) .

10. Apparatus according to claim 6, c h a r a c t e r i z e d in that the brake device (5) is provided with a spring (18) which contributes to the self- increasing braking effect, which, however, when a free end of the belt (1) is pulled in, makes possible an automatic reduction or elimination of the braking effect.