US3137013A

US3137013A - Ships' lifeboat davits

Info

Publication number: US3137013A
Application number: US228190A
Authority: US
Inventors: Devonport John
Original assignee: Samuel Taylor and Sons Brierley Hill Ltd
Current assignee: Samuel Taylor and Sons Brierley Hill Ltd
Priority date: 1961-10-06
Filing date: 1962-10-03
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16

Description

Juhe 16, 1964 J. DEVONPORT SHIPS LIFEBOAT DAVITS 2 Sheets-Sheet 1 Filed Oct. 5, 1962 INVENTOR:

June 16, 1964 Filed Oct. 5, 1962 J. DEVONPORT SHIPS LIFEBOAT DAVITS 2 Sheets-Sheet 2 v INVENTOR: W BY United States Patent "ice 3,137,013 SHIPS LH EBOAT DAVITS John Devonport, Blackheath, England, assignor to Samnel Taylor & Sons (Brierley Hill) Limited, Brierley Hill,

England Filed Oct. 3, 1962, Ser. No. 228,190 Claimspriority, application Great Britain (let. 6, 1961 2 (Ilaims. (Cl. 9-35) This invention relates to davits for launching ships lifeboats, and particularly to davits of the gravity type in which the davit arms, from which the lifeboat is suspended, are guided for rectilinear movement between stowed and boat-lowering positions upon fixedstraight tracks disposed athwartships and inclined downwardly in an outboard direction.

With gravity davits of this type as usually constructed and arranged it is well known that unless the weight of the suspended lifeboat, the weight of the davit arms and the pull on the boat falls are carefully co-related, there is a danger, when'the ship has a list of from 15 to 25, that the lifeboat will drop from the usual suspension hooks or tusks at the head of the davit arms and that the latter will crash inboard with serious consequences.

The present invention has for its object to provide a new or improved lifeboat davit of the type referred to v which will enable the usual suspension hooks or tusks to be dispensed with and obviate the risk of the lifeboat being dropped under adverse extreme list conditions, and which also will have other advantages not previously obtained with davits of said type.

A ships lifeboat davit of the type referred to and according to the present invention is characterized in that the two davit arms, from head sheaves of which the lifeboat is suspended by the falls, are rigidly interconnected and in that a winch for operating said falls moves with the rigidly interconnected davit arms on the inclined tracks Preferably the rigid interconnection of the two davit arms is afforded by a bridge structure extending in a fore and aft direction between their inboard or carriage I ends, and said fall operating winch is mounted preferably centrally upon said bridge structure.

According to a further preferred feature of the invention, a second winch for travelling the rigidly interconnected davit arms upon the inclined tracks is also mounted upon said bridge structure.

Since the fall-operating winch constitutes with th rigidly interconnected davit arms a unitary structure or assembly movable outboard and inboard along the inclined tracks, there is no need for the usual suspension hooks or tusks and associated locking devices at the head of the davit arms, nor is there any need for tricing or bowsing gear, since the suspended lifeboat can be maintained stable throughout the outboard and inboard travel on said tracks, and also while in any position thereon, by gripe wires which lash it securely to the davit arms or other part of said unitary structure or assembly and need not be released until the lifeboat has been brought to the full outboard position, the passengers have taken their places in the lifeboat, and all is ready for lowering the latter down the ships side into the water. In this connection the bridge structure upon which the winch or winches are mounted may be adapted to serve as a platform from which passengers can be embarked into the lifeboat when the latter is in the fully outboard position. The winch operator would, of course, stand upon said platform and he, or another member of the ships crew could supervise the loading of the lifeboat and its lowering away while standing on said platform.

'By employing a separately operable winch for travelling the said unitary structure upon the inclined tracks, the

3,137,013 Patented June 16, 1964 1 suit prevailing conditions; for example, the lifeboat can be stowed in the fully inboard position, or in the fully outboard position, or in any intermediate position on said tracks. Thus the lifeboat may be stowed at the ready for lowering even when the ship is travelling at full speed and, if desired, the boat can be recovered from said fully outboard position and stowed inboard also even while the ship is travelling at full speed.

Since the two winches are entirely separate and do not require to be operated at the same time, their control can be effected by one man on said bridge structure.

Gravitational travel of the said unitary assembly down the inclined tracks may be under the control of a manually operated and weighted brake lever on the second or smaller winch and the latter may be manually operated to travel the said unitary assembly inboard up said inclined tracks, although provision may be made for power operation if desired. Similarly lowering of the lifeboat on its falls may be effected at a predetermined speed under centrifugal brake control and by a manually oper-. able and weighted brake lever on the main or first winch, which latter would, of course, be power operated for hoisting the boat from the water to the davit ready for stowing.

Preferably the inboard ends of the davit arms will be fitted with track engaging rollers, the outboard end of the davit arm being fitted with the usual head sheave. In this connection each davit arm may be of duplex form comprising two side plates or structures with the head sheave and thetrack rollers mounted on short axles or shafts between them. The inclined tracks which maybe flanked or straddled by said duplex davit arms may be of I-section and certain of said rollers may bear down upon the top flange of said section while others mayengage in the laterally presented channels of the section and bear upwardly against the under surfaces of said'tdpfiange so as to ensure against the davit arm tilting. The inboard or carriage ends of said davit arms would be interconnected by the bridge structure or platform on which the winch or winches are mounted, and the requisite guide pulleys for the falls and attachments for the gripe wires would be provided on the said inboard carriage ends. The travelling davit assembly may have its hoisting winchf cable or cables connected to the upper part'of the inclined tracks so that as said cable or cables is or are paid out under brake control the said assembly will be lowered down said tracks. I

The inclined tracks may be deck mounted or they may be mounted between decks providing there is the necessary headroom.

The invention will now be described with reference to and by the aid of the embodiment illustrated, somewhat diagrammatically, in the accompanying drawings: in which:

FIG. 1 is an end elevation of a ships lifeboat davit, and

FIG. 2 is a plan of said davit, drawn to a reduced scale.

Referring to the drawings, the ships lifeboat davit comprises two davit arms 10, having head sheaves 11 from which a lifeboat 12 is suspended by f alls"13, said davit arms 10 being rigidly interconnected by a bridge structure 14 extending in a fore md aft direction between the inboard ends of the dawn arms 10 and forming therewith a unitary assembly which may travel between stowed and boat/lowering positions upon conventional parallel tra cks 15 inclined downwardly in an outboard direction.

A which having drums 16 for operating the lifeboat falls 13 is mounted substantially centrally upon and partly within the bridge structure 14, the falls 13 extending from the winch drums 16, along the length of the bridge structure 14- to pulleys 17, located at the inboard ends of the davit arms 10, and from the pulleys 17 up to the head sheaves '11. A second winch having drums 18 is mounted within the bridge structure 14, adjacent the first Winch, and operates traversing falls 19 for travelling the unitary assembly comprised by the davit arms and the bridge structure 14 upon the inclined tracks 15, the traversing falls 19 extending from the winch drums 18 to pulleys 20, located at the inboard ends of the davit arms 10, and then from the pulleys 20 in an inboard direction to pulleys 21 which may be either secured to the upper part of the tracks 15, as shown in the drawings, or to the deck housing 22. The ends 19a of the traversing falls 19 are secured to pillars 23, supporting the upper ends of the tracks 15, as shown in FIG. 1, so that as the falls 19 are paid out the unitary assembly will be lowered down said tracks 15. r

The winch drums 16 are driven by an electric motor 24 through a reduction gear unit 25 and in the event that the power supply to the motor 24 fails, these winch drums may be driven by a winch handle 26 (shown in FIG. 1) which engages the squared end of a shaft 27 projecting from the gear unit 25. The winch drums 18 are manually operated by a winch handle 28 (shown in FIG. 1) which engages the squared end of a shaft 29 projecting from a gear unit 30 associated with the said second winch.

Gravitational travel of the unitary assembly down the inclined tracks 15 would be under the control of a manually operated and weighted brake lever (not shown) on the winch 18 and similarly lowering of the lifeboat on its falls would be effected at a predetermined speed under centrifugal brake control and by a manually operated and weighted brake lever (not shown) on the winch 16.

Each davit arm 10 is of duplex form comprising two side plates with the head sheaves 11 and rollers 31 and 32 for engaging the tracks. 15 mounted on short axles or shafts between them. The inclined tracks 15 are of I- section and are flanked or straddled by the duplex davit arms 10, each roller 31 bearing down upon the top flange of the engaged track section and each roller 32 engaging in the laterally presented channels of the said section and bearing upwardly against the under surface of said top flange so as to ensure against the davit arms 10 tilting.

The bridge structure 14 would, when the lifeboat davit is in use, have a rigid cover to serve as a platform from which passengers could be embarked into the lifeboat when the latter is in the fully outboard, fully inboard or in any intermediate position. As applied to davits for large lifeboats, the bridge structure 14 may be high enough to permit the embarkation of the passengers into the lifeboat through this structure instead of over the top, and the upwardly projecting portions of the winch 16, motor 24- and gear unit 25 would preferably be covered by a suitably shaped cowling to avoid possible injury to passengers on the platform.

Having fully described my inventiomwhat I claim and desire to secure by Letters Patent is:

l. A ships lifeboat davit of the gravity type having a pair of inclined tracks extending laterally downwardly with respect to the side of a ship, a pair of davit arms each of which is provided with a sheave at the outboard end' thereof, a fall received in each of said sheaves, a

lifeboatsuspended adjacent its opposite ends from the repective falls whereby the weight of said lifeboat is at all times borne by said falls, a bridge structure rigidly interconnecting said davit arms, said bridge structure extending in a fore and aft direction between the inboard ends of the davit arms, each of said davit arms provided with'means engaging said inclined tracks for enabling gravitational movement of said davit arms, bridge structure and suspended lifeboat along said inclined tracks from the inboard ends toward the outboard ends of the latter, means including a winch mounted on said bridge structure intermediate its ends for controlling said movement, and a second winch mounted on said bridge structure adjacent said first winch for controlling said'falls and the lowering of the lifeboat.

2. Aships lifeboat davit as set forth in claim 1 wherein each of said tracks are of I-section and are straddled by a respective davit arm, each of the latter having a roller engaging the top flange of the section. andhaving 1 also a second roller positioned within a channel of the section and engaging the under surface of said top flange to prevent tilting of thedavit arms.

References Cited the file of this patent UNITED STATES PATENTS Great Britain of 1912

Claims

1. A SHIP''S LIFEBOAT DAVIT OF THE GRAVITY TYPE HAVING A PAIR OF INCLINED TRACKS EXTENDING LATERALLY DOWNWARDLY WITH RESPECT TO THE SIDE OF A SHIP, A PAIR OF DAVIT ARMS EACH OF WHICH IS PROVIDED WITH A SHEAVE AT THE OUTBOARD END THEREOF, A FALL RECEIVED IN EACH OF SAID SHEAVES, A LIFEBOAT SUSPENDED ADJACENT ITS OPPOSITE ENDS FROM THE RESPECTIVE FALLS WHEREBY THE WEIGHT OF SAID LIFEBOAT IS AT ALL TIMES BORNE BY SAID FALLS, A BRIDGE STRUCTURE RIGIDLY INTERCONNECTING SAID DAVIT ARMS, SAID BRIDGE STRUCTURE EXTENDING IN A FORE AND AFT DIRECTION BETWEEN THE INBOARD ENDS OF THE DAVIT ARMS, EACH OF SAID DAVIT ARMS PROVIDED WITH MEANS ENGAGING SAID INCLINED TRACKS FOR ENABLING GRAVITATIONAL MOVEMENT OF SAID DAVIT ARMS, BRIDGE STRUCTURE AND SUSPENDED LIFEBOAT ALONG SAID INCLINED TRACKS FROM THE INBOARD ENDS TOWARD THE OUTBOARD ENDS OF THE LATTER, MEANS INCLUDING A WINCH MOUNTED ON SAID BRIDGE STRUCTURE INTERMEDIATE ITS ENDS FOR CONTROLLING SAID MOVEMENT, AND A SECOND WINCH MOUNTED ON SAID BRIDGE STRUCTURE ADJACENT SAID FIRST WINCH FOR CONTROLLING SAID FALLS AND THE LOWERING OF THE LIFEBOAT.