US3157891A

US3157891A - Ships' lifeboat davits

Info

Publication number: US3157891A
Application number: US309549A
Authority: US
Inventors: Davonport John
Original assignee: Samuel Taylor and Sons Brierley Hill Ltd
Current assignee: Samuel Taylor and Sons Brierley Hill Ltd
Priority date: 1962-10-13
Filing date: 1963-09-17
Publication date: 1964-11-24
Anticipated expiration: 1981-11-24
Also published as: GB969575A

Description

Nov. 24, 1964 J. DEVONPORT SHIPS LIFEBOAT DAVITS 2 Sheets-Sheet 1 Filed Sept. 17, 1963 INVENTOR:

J. DEVONPORT SHIPS LIFEBOAT DAVITS Nov. 24, 1964 2 Sheets-Sheet 2 Filed Sept. 17, 1965 Fig. 2.

United States Patent 3,157,891 SHEPS LKFEEBAT lDAVlTS John Davenport, Blaclrheath, Birmingham, England,

assignor to Samuel Taylor 8; Sons (Brierley Hill) Lunited, Brierley Hill, Staifordshire, England Filed Sept. 17, 1963, Ser. No. 399,549 Claims priority, application Great Britain, Get. 13, 1962, 38,836/62 2 Claims. (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 head sheaves on which the lifeboat is suspended by falls, are guided for rectilinear movement between stowed and boat-lowering positions upon fixed tracks disposed athwartships and inclined downwardly in an outboard direction.

With ships lifeboat davits of this type as usually constructed or arranged, the winch which operates the lifeboat falls is deck-mounted and consequently the winch operator, who controls the lowering by appropriately manipulating the brake release lever on the winch, can not leave the ship in the event of an emergency until the lifeboat, with its complement of crew or passengers, has been lowered into the water, whereupon, in order to save himself, he must either slide down a rope, or descend a special rope ladder, into the boat below. However, there are certain emergencies at sea, for example those involving oil tankers and the sea around is covered by burning oil, in which there is not time to be wasted by awaiting the winch operator to follow from ship to lifeboat after the latter becomes waterborne and consequently he must be left to escape as best he can or perish.

A ships lifeboat davit of the type referred to and according to the present invention has the davit arms rigidly interconnected to afford a unitary assembly and is characterized in that the winch for operating the lifeboat falls is mounted upon said assembly, so as to partake of the movements thereof upon the tracks, and is so disposed on said assembly that when the latter is in the boat-lowering position the winch brake release lever can be operated by a flexible line depending therefrom, or from an associated auxiliary release lever, into the suspended lifeboat. Thus the arrangement is such that the winch operator, once the unitary davit assembly has been brought into the extreme outboard or boat-lowering position and the crew members or passengers have been transferred to the suspended lifeboat, can immediately board the lifeboat and lower it until it becomes waterborne simply by appropriately pulling on the depending line, which would, of course, be of suflicient length to accommodate all loading conditions of the ship and up to 25 of adverse list. When the boat becomes waterborne any of the operating line remaining in the boat would be cast off or payed out into the sea as the boat is pulling away from the ship.

According to a preferred feature of the invention, the operating line depending from the winch brake release lever, or associated auxiliary release lever, into the suspended lifeboat is coiled upon a free-running spool or reel but with the lower end of the line properly seized and left free to be carried away after the boat becomes waterborne. The said spool or reel is preferably readily portable and the depending line is preferably led to it through a guide, which latter conveniently may be afforded by an appropriately positioned slot in a lifeboat seat under which the spool or reel can be stored in a safe and unobtrusive position.

The invention will now be more fully described with reference to the preferred embodiment illustrated in the accompanying drawings, in which:

FIG. 1 is an end elevation of a ships lifeboat davit of l ce the gravity type referred to and showing the lifeboat in the stowed position.

FIG. 2 is a view similar to FIG. 1 but showing the davit arms in the fully outboard position and with the boat being lowered away by the winch operator.

FIG. 3 is a fragmentary side elevation of a bridge structure, which interconnects the davit arms to form a unitary assembly.

Referring to the drawings, the ships lifeboat davit comprises two davit arms 10 (only one of which is shown), having head sheaves 11 from which a lifeboat 12 is suspended by falls 13, said davit arms 10 being rigidly interconnected by a bridge structure 14 extending in fore and aft direction between the inboard ends of the davit arms 10 and forming therewith a unitary structure which can travel between stowed and boat-lowering positions (see FIGS. 1 and 2 respectively) upon conventional parallel tracks 15 inclined downwardly in an outboard direction.

A winch 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 said pulleys 17 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 said unitary assembly upon the inclined tracks 15, which falls 19 pass over guide pulleys (not shown) and rearwardly to appropriate fixed anchorages, say for example brackets 20 at the upper ends of said tracks 15.

The winch drums 18 are manually operated by a Winch handle (not shown) which engages the squared end of a shaft 21 projecting from a gear unit 22 on the housing 23 or" the said second winch, while the winch drums 16 are driven by an electric motor 24 through a reduction gear unit 25 and, in the event of said motor 24 or its supply failing, these winch drums 16 may be driven by a winch handle (not shown) applied to the squared end of a shaft 26 projecting from the gear unit 25.

Each davit arm It is of duplex form comprising two side plates with the head sheaves 11 and track engagingrollers 27 and 28 mounted on short axles between them. The inclined tracks 15 are of l-section and are flanked or straddled by the duplex davit arms 10, each roller 27 bearing down upon the top flange of the engaged track section and each roller 28 engaging in a laterally presented channel of said section and bearing upwardly against the under surface of said top flange so as to ensure against the davit arms 10 tilting.

Gravitational travel of the unitary assembly down the inclined tracks 15 would be under the control of a manually operable and weighted brake lever (not shown) and is determined by stops 29 fixed in the side channels of said tracks 15 for engagement by the rollers 28 when the davit arms 10 are in the fully outboard or boat-lowering position.

Lowering of the lifeboat 12 on its falls 13, after simultaneously releasing grip wires 30 by operating a hand lever 31 on the bridge structure 14, is effected at a predetermined speed by a centrifugal brake 32 under the manual control of a weighted .brake release lever 33 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.

In order to enable the brake 32 to be released and controlled by the winch operator from the lifeboat 12, once the unitary davit assembly has been brought into the extreme outboard or boat-lowering position and the passengers and crew members have boarded the suspended lifeboat, there is provided on the bridge structure 14 an auxiliary release lever 34 which is pivoted at 35. The inboard end of this auxiliary release lever 34 projects beyond the pivot 35 to a position immediately below the main release lever 33, which is biassed to the brake-applied position, and the outboard end of said auxiliary lever 34 projects over the suspended lifeboat 12 and has an attached flexible line 36 which is of sufficient length to accommodate all loading conditions of the ship and up to 25 of adverse list. Thus the winch. operator in the lifeboat 12 can, simply by appropriately pulling on the depending line 36, initiate and control the lowering of the lifeboat 12 until it becomes waterborne, whereupon any of the line 36 remaining in the lifeboat 12 can be cast off or payed out into the sea as said boat is pulling away from the ship.

Preferably, and as shown in the drawings, the operating line depending from the auxiliary lever 34 into the lifeboat 12 is coiled upon a free-running spool or reel 37 but with the lower end of said line 36 properly seized and left free to .be carried away after the boat becomes waterborne. In this connection said spool or reel 37 is preferably readily portable and the depending line 36 is led to it through a guide conveniently afforded by an appropriately positioned slot in a lifeboat seat 38 under which the spool or reel 37 can be stored in a safe and unobtrusive position.

Instead of the main brake release lever 33 being operable by the flexible line 36 through the medium of an auxiliary lever 34 as above described, it may be adapted or arranged for direct operation by said flexible line 36, for example by attaching said line 36 to the lever 33 and providing appropriately positioned guide pulley (not shown) over which said line 36 passes before depending into the lifeboat 12, the arrangement being such that when the depending position of the line 36 is pulled by the winch operator in the suspended lifeboat 12 the brake release lever 33 is raised to free the brake 32 and ailow the lifeboat 12 to lower away.

Having fully described my invention, what 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 and downwardly from the side of a ship, a pair of davit arms each of which is provided with a sheave at the outboard end thereof for receiving a fall from which a lifeboat is suspended, 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 inciined tracks from the inboard ends toward the outboard ends thereof, means including a winch mounted on said bridge structure for controlling said movement, a second winch mounted on said bridge structure substantially amidship of the span between the davit arms for controlling said falls and the lowering of the lifeboat, said second winch provided with a brake, a brake release lever carried by said bridge structure for releasing said brake, said lever projecting over the suspended lifeboat, and means for operating said brake release lever from the suspended lifeboat after movement thereof to the outboard ends of said inclined tracks to control the lowering of the lifeboat comprising a manually operable flexible line extending into the lifeboat and having one, end thereof secured to said brake release lever.

2. A ships lifeboat davit as set forth in claim 1 wherein the flexible line which extends into the lifeboat is coiled upon a free-running spool, the lower end of the line being left free to be carried away after the lifeboat becomes waterborne.

References Cited by the Examiner UNITED STATES PATENTS 1,833,199 11/31 Beagle 9--4(] 2,141,452 12/38 Schat 9-38 FOREIGN PATENTS 916,712 8/46 France. 833,681 4/60 Great Britain.

53,370 1/23 Sweden.

FERGUS S. lViIDDLETOMPrimary Examiner.

Claims

1. A SHIP''S LIFEBOAT DAVIT OF THE GRAVITY TYPE HAVING A PAIR OF INCLINED TRACKS EXTENDING LATERALLY AND DOWNWARDLY FROM THE SIDE OF A SHIP, A PAIR OF DAVIT ARMS EACH OF WHICH IS PROVIDED WITH A SHEAVE AT THE OUTBOARD END THEREOF FOR RECEIVING A FALL FROM WHICH A LIFEBOAT IS SUSPENDED, 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 THEREOF, MEANS INCLUDING A WINCH MOUNTED ON SAID BRIDGE STRUCTURE FOR CONTROLLING SAID MOVEMENT, A SECOND WINCH MOUNTED ON SAID BRIDGE STRUCTURE SUBSTANTIALLY AMIDSHIP OF THE SPAN BETWEEN THE DAVIT ARMS FOR CONTROLLING SAID FALLS AND THE LOWERING OF THE LIFEBOAT, SAID SECOND WINCH PROVIDED WITH A BRAKE, A BRAKE RELEASE LEVER CARRIED BY SAID BRIDGE STRUCTURE FOR RELEASING SAID BRAKE, SAID LEVER PROJECTING OVER THE SUSPENDED LIFEBOAT, AND MEANS FOR OPERATING SAID BRAKE RELEASE LEVER FROM THE SUSPENDED LIFEBOAT AFTER MOVEMENT THEREOF TO THE OUTBROAD ENDS OF SAID INCLINED TRACKS TO CONTROL THE LOWERING OF THE LIFEBOAT COMPRISING A MANUALLY OPERABLE FLEXIBLE LINE EXTENDING INTO THE LIFEBOAT AND HAVING ONE END THEREOF SECURED TO SAID BRAKE RELEASE LEVER.