US2949617A

US2949617A - Ships' lifeboat davits

Info

Publication number: US2949617A
Application number: US616883A
Authority: US
Inventors: Harry R Powell; Thomas H Wolverson
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-10-18
Filing date: 1956-10-18
Publication date: 1960-08-23
Anticipated expiration: 1977-08-23

Description

Aug. 23, 1960 H. G. TAYLOR SHIPS LIF'EBOAT DAVITS 2 Sheets-Sheet 1 Filed Oct. 18, 1956 A itorneys Aug. 23, 1960 H. G. TAYLOR 2,949,617

SHIPS LIFEBOAT DAVITS 2 Sheets-Sheet 2 Filed Oct. 18, 1956 SHIPS LIFEBOAT DAVITS Ge'orge Taylor, deceased, late of Wolver- Humphrey hampton, England, by Harry R. Powell, Stourbridge, England, and Thomas H. Wolverson, 47 Queen St., Wolverhampton, England, administrators more particularly to davits for launching lifeboats from stowed positions between decks.

According to the present invention, each of the davit arms, from the outboard ends of which the lifeboat is suspended, is fitted with two or more rollers engaging a fixed straight track which is disposed athwartships between the two decks, and the davit arm is loaded in the outboard direction by a weight freely suspended by a rope or cable which passes over a pulley or pulleys and is connected to an anchorage on the davit arm so as to exert an outboard pull thereon to effect, or assist in effecting, the outboard movement of the davit arm when the usual control ropes are payed-out by the winch.

The fixed track may be horizontal, though, preferably, it will be inclined downwardly in an outboard direction from a position immediately below the upper deck.

According to a further preferred feature of the invention, there is provided at the head or outboard end of each davit arm a pivotally mounted boat-suspension hook or tusk for engaging the lifeboat block, said hook or tusk being automatically operated by the suspended load to release the said block when the outboard position is reached and having associated therewith a device for holding said hook or tusk in its block-retaining and block-released positions, the arrangement being such as to prevent the boat being released and falling away from the davit arm until the latter has travelled to the outboard position; to prevent the davit arm from being drawn back up the track, instead of lowering away the boat, when the hook or tusk is held in the blockreleased position, and to ensure that the davit arms with the boat suspended on the hook or tusk cannot be pulled inboard up the track from the outboard position unless the said hook or tusk is held in its block retaining position.

The invention will now be described with reference to the embodiment shown in the accompanying drawings; wherein:

Fig. 1 is a fragmentary sectional view taken athwartships and showing, in full outline, the davit arms with the lifeboat suspended therefrom in stowed position between decks and, in chain lines, the extreme outboard position of the davit arm and lifeboat and also a further position of the latter as it is being lowered away.

Fig. 2a is an enlarged fragmentary side elevationshowing the davit arm in its outboard position and the suspension hook in boat releasing position;

Fig. 2b is a view similar to Fig. 2a but showing the davit arm in its inboard position and the hook in boat supporting position; and

Fig. 3 is a top plan view of the davit arm in its position of Fig. 20.

Referring to the drawings, and more particularly to Fig. 1, each of the two davit arms 10, trom the outboard end of which the lifeboat 11 is suspended, is fitted with outer and

inner rollers

12, 13 respectively which engage atent O a fixed straight track 14, of duplex form, which track 14 is disposed a-thwartships between upper and lower decks 15, '16 respectively, and said davit arms 10 are each loaded in the outboard direction by a weight 17 freely suspended by a rope or cable 18 which passes over a system of pulleys comprising two inboard fair-lead pulleys 18a and 18b, pivotally fixed to the ships structure, and an outboard pulley 19 which is pivotally carried on the track 14 as more particularly shown in Fig. 3. From the pulley 19 the cable leads to an anchorage 20 inboard of the pulley on the davit arm 10 so that the weight through the pulley exerts an outboard pull on the davit arm 10 to effect or assist in effecting, the outboard movement of the davit arm 10 when the usual control ropes are payed out by the winch 21. The track 14 is inclined downwardly in an outboard direction from a position immediately below the upper deck 15, the arrangement being such that, except under abnormal conditions of adverse list, outboard movement of the davit arms 10 will be effected either wholly by the pull exerted by the suspended weights 17 or partly by said pull and partly by the direct gravitational load of the davit arms 10 upon their tracks 14 so long as these have a favourable inclination. In the latter event, the proportion in which these two forces act to efiect outboard movement of the davit arms 10 will vary with the list; thus with increasing adverse list the proportional effect of the suspended weights 17 will increase and that of the direct gravitational load on the tracks 14 will decrease. In this connection, the inclined setting of the tracks 14 and the size of the suspended weights 17 which assist the outboard movement of the davits 10 will preferably be such as to ensure that launchings can be carried out successfully under conditions involving up to at least 25 of adverse list.

Each weight 17 works in a normally vertical housing or guideway 22 in the ships side and disposed clear fore and aft of the path of travel of the boat, the fair-lead pulleys 18a and 18b leading the cables to the trackways in a manner Well recognized by those skilled in the art.

The outboard movement of each davit arm 10 is determined by its roller 12 engaging the closed outer end of its track 14 which serves as a stop, and each davit arm 10 is of very wide or obtuse V-shape, the limb with the inboard direction from the included angle, and which has the track

engaging rollers

12, 13 on it, being aligned with the fixed track 14, whilst the other limb is either substantially horizontal or, as shown has a small upward inclination to its outboard end which carried the usual head sheave 23, the pivotally mounted suspension hook or tusk 24 and associated locking device which is hereina-fter more fully described.

The lifeboat 11 is suspended from the head sheaves 23 on the davit arms 10 by the usual pulley blocks 25 and control ropes or falls 26 which pass inboard over guide pulleys 27 to the winch 21.

Referring now more particularly to Figs. 2a, 2b and 3, the locking device for each suspension hook or tusk 24 comprises a bell crank lever 29 pivotally mounted at 30in the rear end of the davit arm 10, said lever 29 having an upwardly directed limb connected by a pivoted link or connecting rod 3-1 to said hook or tusk 24 and having coaxial rollers 32 mounted at the extremity of its other limb which extends inboard from the pivot 30, which rollers 32 normally bear down upon track surfaces or flanges 33, which are parallel to the surfaces of the tracks -14 engaged by the

rollers

12, 13, so that the books or tusks 24 are maintained in the block-engaged position throughout the travel of the davit arms 10. These track surfaces or flanges 33 terminate in downwardly swept and curved outer end portions 34 at such a position that the rollers 32 become unsupported when the rollers 12 are arrested by the closed outer ends of the tracks 14, whereupon the levers 29 automatically rock down and, through the connecting rods 31, disengage the hooks or tusks 24 from the eye pins 28 of the blocks 25, such movement being stopped by the rollers 32 coming down upon the outwardly curved lower ends of the said end portions 34 of the track surfaces or flanges 33 as shown in chain lines in Figs. 2a and 2b. Thus the lifeboat 11 becomes suspended only by its blocks 25 and falls 26, the eye pins 28 of said blocks 25 having been released by the hooks or tusks 24 so that the lifeboat 11 is free to be lowered away by continued paying out of the falls 26, but the actual transfer of the suspended load from the hooks ortusks 24 to the falls 26 does not take place until after the initial part of the downward swinging movement has brought the rollers 32 into a position in which, by engaging the downswept track portions 34, they will lock the davit arms against any tendency to run back up the tracks 14 as the suspended load is taken by the falls 26 and the latter continue to be payed out to lower away the lifeboat 11.

The hook or tusk 24 is formed with a radial arm 35 which, when the hook or tusk 24 is in the fully released position shown in chain lines in Fig. 2a, is disposed above the block 25, the arrangement being such that when the lifeboat '11 is again raised the said block 25 engages the radial arm 35 and rocks the hook or tusk 24 back so as to return it to the block-retaining position in engagement under. the eye pin 28 and at the same time, through the connecting rod 31, rocking up the lever 29 so as to disengage the rollers 32 from the downswept portions 34 of the track surfaces or flanges 33 and so free the davit arm 10 for inboard movement up the track 14 under the pull of the falls 26 as they continue to be wound in by the winch. Thus the rollers 32 again become supported by the track surfaces or flanges 33, and the hook or tusk 24 is thereby locked and cannot release the block 25 until the davit arm 10 is again run out to and has reached its fully outboard position.

The davit arms may be connected by separate rope to the same suspended weight so that it will be applied equally to them so long as they have the same freedom of movement but otherwise will be applied only to the more sluggish arm until it has caught up with the freer arm.

Having fully described the invention, what we claim and desire to secure by Letters Patent is:

l. A ships lifeboat davit of the type having two davit arms from the ends of which a lifeboat is suspended, a pair of fixed straight tracks disposed athwartships be tween two decks, rollers connected to said arms and engaging said tracks so as to permit movement of said davit arms between outboard and inboard positions, a pulley pivotally fixed to said tracks, a flexible element leading over said pulley and having one end anchored to said davit arms inboard of said pulley, and a weight suspended from the opposite end of said flexible element to exert at all times a force on said davit arms in an outboard direction.

2. The davit as claimed in claim 1 wherein the fixed track for each davit arm is inclined downwardly in an outboard direction with the outboard end thereof having stop means integral therewith to engage one roller 4 on said arm to determine the degree of outboard movement of said arm.

3. A ships lifeboat davit as claimed in claim 1 including a boat suspension hook for engaging a lifeboat block, said hook being pivotally mounted at the outboard end of each davit arm for movement between block reraining and block released positions, linkage means connected to said hook and responsive to the movement of said davit arm to Outboard position for enabling the suspended load to pivot said hook to block released position, means acting on said linkage means for holding said hook in block retaining position until said davit arm has moved to its outboard position, means engageable with said linkage means for preventing the davit arm from being moved'up its track toward its inboard position when said hook is pivoted to block released position, said linkage means being moved out of engagement with said last named means upon movement of said hook to block retaining position so as to enable said davit arm to be. moved inboard up said track.

4. A ships lifeboat davit of thetype having davit arms from the. outboard ends of which the lifeboat is suspended, eachof said arms being of obtuse V-shape having an inboard limb, rollers fitted to said inboard limb, a fixed straight track dis-posed athwartships between two decks and engaged by said rollers, said track being inclined downwardly in an outboard direction from a position immediately below the upper deck, the outboard end of said track being closed to provide a stop engageable by the outermost roller on said davit arm to determine its outboard movement, a pulley pivotally fixed with respect to said track, a flexible element leading over said pulley and having one end anchored to said arm inboard of said pulley, a weight suspended from the opposite end of said flexible element, and a normally vertical guideway in the ships side for receiving said weight, said weight exerting at all times an outboard pull on said davit arm.

5. A ships lifeboat davit as claimedv in claim 4, wherein a boat suspension book for engaging a lifeboat block is pivotally mounted on the outboard end of each davit arm, means responsive to engagement of the outermost rollerwith the closed: outboard end of said track for enabling said hook to be automatically operated by the suspended load to release said block, said means including' aleveroperatively connected-to the hook to hold the same in-its block-retaining position except when the davit arm is. in its outboard position, a roller carried by the lever, a trackengageable by the roller, said track having a downswept portion at its outboard end to receive said roller when said davit arm reaches its out-board position, movement of said roller into said downswept portion operating said lever to move said hook to block-released position, engagement of said roller with said downswept portionpreventingreturn of said davit arm to its inboardposition until said hook has been returned to its block-retaining position.

References Cited in; the file of this patent UN T D Z TES A EN 2,028,513 Marten Ian. 21, 1936 2,239,253 Schat Apr. 22, 1941 2,667,649 Elling Feb. 2, 1954