US1389338A - Ship's davit - Google Patents

Description

' n. H. ALEXANDER AND T. GRAHAM.

SHIPS DAVIT.

APPLICATION FILED ran. 20, I920- RENEWED JULY 23, I921.

1 ,389,338. I Patented Aug. 30, 1921.

2 SHEETS-SHEET I- n. H. ALEXANDER AND T. GRAHAM.

"SHIP'S DAVIT.

APPLICATION FILED FEB. 20, 1920. RENEWED JULY 23.1 921.

-1,389,338. I PatentedAug.30,1921.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

ROBERT HILLS ALEXANDER, OF WILLINGTON QUAY, AND THOMAS GRAHAM, OF I SUNDERLAND, ENGLAND.

SHIPS DAVIT.

Specification of Letters Patent. Patented Aug. 30, 1921- Application filed February 20, 1920. Serial No. 360,082. Renewed July 23, 1921. Serial No. 487,132;

To all whom it may concern:

Be it known that we, Ronnn'r HILLS ALEX- ANDER, residing at VVillington Quay, and THOMAS GRAHAM, residing at Sunderland, both in the county of Durham England, subjects of the King of England, have invented certain new and useful Improvements in Ships Davits, of which the following is a specification.

This invention relates to improvements in ships davits of the kind in which the boat is.slung from a single curved davit arm pivoted at its lower end for swinging move ment inboard and outboard'and comprising screw gear for effecting such movement and suitable winding gear with tackle for raising and lowering the boat, the present invention consisting incertain novel features and combinations of parts as hereinafter described and claimed. 5

The improved ships davit constructed according to this invention comprises a single curved supporting arm or jib formed so that its upper or outer portion is comparatively narrow and slender as seen transversely to the longitudinal axis of the ship on which it is assumed to be mounted, and toward its lower end it is splayed out in both directions so as to form a laterallyem tended frame on which boat supporting chocks may be mounted, there being ample space between the chocks to give support to the boat fore and aft; The arm is so curved as to clear the mid section of the boat when inboard and so that the latter may have its center of gravity well inward of the axis of the arm. The arm is pivoted on widely separated centers substantially beneath the respective chocks. It is provided with two pairs of chocks, one of each pair substantially parallel with the arm, and the other of each pair extending forwardlyat an angle. The clearance between the arm and the boat is thus reduced to a minimum when the boat is in inboard position. The arm is mounted on a pivotal axis so that the point of suspension of the tackle is vertically above the center lin of the boat when inboard.

The tilting of the arm is advantageously effected by a screw gear operating a sliding member connected by a link to the arm and the tackle by a winch carried by the said member.

Referring to the accompanying drawings illustrating an embodiment of the invenionz- Figure 1. is a side elevation showing a davit in normal position. V

Fig. 2 is a similar viewshowing the davit tilted outboard in the launching position.

Fig. 3 is a rear view.

Fig. 4 a side view'showing boats on two deeiks adapted to be operated by one davit, an

Fig. 5 is a plan showing means for connecting the .fall to the boat.

a designates the arm of jib pivotally conneoted to the deck at b and provided at its upper end with a pulley 03, said arm being advantageously built up as shown in Fig. 3 of two members 6 f suitably connected by ties. a pair of brackets gg forming chocks for the boat, one of said bracket members g being preferably pivotally connected at g to its neighbor as shown, so that by releasing avpin i it can be dropped to give access to the bottom of the boat. Mounted in a frame 71 behind the arm a; is a worm 7' adapted to be rotated by a handle 7' said worm having thereon a nut k connected to a can .riage Z which is suitably mounted on the frame it and connected to the arm a by a link m. On the carriage is mounted a winch n from the drum of which a rope o'passes over a pulley (Z to a pulley block 7), the latter carrying a hook Q of the self-releasing type which is adapted to be connected to a sling attached to the boat, one form of sling bein shown by way of example in Fig. 5 in which the sling ropes s are connected to lugs s pivoted on the boats keel.

In Fig. 4c the davit is shown mounted on a boat deck and another boat supported on chocks t on the deck below. In this case a slot is cut in the deck on which the davit stands to allow the tackle to be lowered and the hook to be attached to the boat below after the upper one has been lowered.

The screw gear 7' 7c and the winch may be Connected to the arm on each side are power operated if desired, or provision may.

be made for both hand and power operation.-

In operation, when it is desired to lower the boat, the hook is attached to the slings.

The falls are tautened by the winch 7' so as" to raise the boat rom the chocks. The arms are then moved outward on their pivots by the screw gear 7 g. The boat is then lowered by the winch.

A davit made in accordance with this invention can be easily and quickly manipulated. The distance between the boat and the side of the vessel can be altered during launching, and all danger resulting from the tackle jamming in the blocks is avoided, and further as shown two or more boats can be lowered by one operation.

\Vhat we claim as our invention and deshe to secure by Letters Patent; of the United States is 1. In a shipsdavit the combination of a single curved davit arm broadened in each direction internally toward its pivotal axis, itscurvature being such that when inboard, the pivotal axis is exterior of the vertical plane containing the longitudinal center line of the boat. andthe extremity of the arm in said vertical plane two laterally widely spaced bearings attached'tothe ships deck carrying said pivotali axis, andliftingtackle for the boat carried by the extremity of the arm.

2. Ina ship7s davit the combination of a singlecurved davit arm broadened laterally toward its pivotal axis, its curvature being suchthat when inboard, the pivotal axis is exterior of the vertical plane containing thelongitudinal center line of the boat and the extremity of the arm in said vertical plane, laterally spaced bearings carrying said pivotal axis, and lifting tackle for the boat carried by the extremity of the arm, together with a couple of pairs of chocks carried by the lateral extensions respectively .of said arm, one chock parallel to the arm and the other chock projecting therefrom at an angle, to support a boat thereon.

3. In a ships davit the combination of a single curved davit arm broadened laterally toward its pivotal axis, its curvature being such that when inboard the pivotal axis is exterior of the vertical plane containing the longitudinal center line of the boat and the extremity of the arm in said vertical plane, laterally spaced bearings on the ships deck ROBERT HILLS ALEXANDER. THOMAS GRAHAM.

Vitnesses C. A. VVALTER, BERTI-IA M. Cnow.

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