US2683271A - Gravity davit - Google Patents

Description

H. G. TAYLOR GRAVITY DAVIT July 13, 1954 Filed Feb. 14, 195i 2 Sheets-Sheet 1 FIG.3.

INVENTOR HUMPHREY GEORGE TAYLOR ATTORNEY July 13, 1954 H. G. TAYLOR YGRAVITY DAVIT 2 Sheets-She'et 2 Filed Feb. 14, 1951 H E F INVENTOR HUMPHREY GEORGE TAYLOR ATTORNEY Patented July 13, 1954 UNITED smrss TEN FFICE GRAVITY DAVIT Humphrey G. Taylor, Lower Penn, near Wolverhampton, England 6 Claims.

The invention relates to davits whether used for supporting or launching ships, boats or used in connection with accommodation ladders.

According to the invention a davit of a davit assembly is pressed outwardly by elastic means, such as a spring, during the Whole or a part of its outboard movement. In the case of lufiing davits, to which the invention is more particularly applicable, the spring pressure is conveniently applied during the period from the inboard position to a position somewhat past the top dead centre, as beyond such position gravity is available to efiect the rest of the outboard movement.

Each spring may be of the torsion, compression, tension or scroll type and may act directly on the respective davit or on an arm pivoted to a fixed part of the vessel and adapted to bear against the respective davit in a manner to move it to its outboard position or sufficiently far to allow gravity to effect the final movement.

In the case of a luffing davit it may be initially or wholly pressed outward by a torsion rod or tube rigidly secured each at one end to the respective davit or to a pivoted arm adapted to bear against the respective davit in a manner to swing the davit from its inboard position to a position where further movement will be effected by gravity. The other end of the torsion rod or tube may be rigidly secured to some fixed part which may be the housing of the other davit of the pair.

In the case where the davits are each mounted on a carriage moved bodily on horizontal or nearly horizontal tracks, such movement or an initial part thereof may be effected by a compression coil spring bearing outwardly against the carriage and anchored at its inner end to a fixed part of the ship. The spring may be encased in a sheath which may be of telescopic form.

An application to a pair of davits for supporting, stowing or raising a ships accommodation ladder is described with reference to the accompanying drawings, in which:

Fig. l is a view of one of the davits of a pair as seen looking longitudinally of a ship to which the davits are fitted and showing also, in end elevation, an accommodation ladder carried by the davits, the latter being shown in their inboard positions.

Fig. 2 is a view corresponding to Fig. l, but showing the davits in their outboard positions and the accommodation ladder suspended from them.

Fig. 3 is a plan view of the parts shown in Fig. 2 in the positions they occupy as depicted in that figure.

Fig. 4 is a similar view to Fig. 1, but illustrating an application of the invention to one of a pair of lufiing davits for a ships boat.

Figs. 5 and 6 are respectively a plan View and an end View of an assembly of two lufiing davit arms and in which the arms are spring-pressed outwardly the whole of their outboard movement.

Fig. 7 is a section view with parts broken away taken substantially on line 1-1 of Fig. 3.

In the embodiment shown in Figs. 1, 2 and 3 of the drawings, 6 indicates the davit pivoted at I to a deck fitting 8 and carrying a yoke 9 to which one end of the accommodation ladder H3 is attached by easily releasable shackles i 1. When the davit has been swung to its outboard position, the yoke 9 with its respective ladder end, can be lowered to the required position by paying out a fall l2 which extends from a winch (not shown) over pulleys 53, hi, l5 and to, being anchored at IT to the yoke 9.

When the davit is being wound inboard, and before it reaches its top dead centre, a lug it on the davit encounters, and presses back, an upwardly extending arm l9 which is rigidly attached to a torsion rod 26 journalled at its one end to the deck fitting 8', and, at its other end, not shown, it is fixed in a deck fitting to which the other davit also not shown is pivoted. Rigidly attached to the torsion rod or spring means 2%, at such other end, is a downwardly extending arm 2 I shown by broken lines in Figs. 1 and 2 and serving to take the torque reaction of the torsion rod or spring means 20. Further inboard movement of the davit presses back the arm i9 against the resistance of the torque rod 29 so that the latter becomes armed.

On the release of the fall l2 the armed torsion rod 2!), acting on the arm is, causes the latter to press against the lug i8 and so impel the davit in an outboard direction until it has passed sufiicientiy beyond its top dead centre to ensure that it will leave the arm 19 and continue its outboard movement by the action of gravity.

In the embodiment shown in Fig. 4, each davit E is spring-pressed outwardly during the initial part of its outboard movement about its pivotal mounting l by an arm I9 fixed on the rotationally free end of a torsion rod 2!]. The davit 6 is allowed to move outboard under the action of the arm 19 by paying out the fall 1 2. When the davit 6 has moved out well beyond the top dead centre it leaves behind the arm 59 and comes to rest upon the side support 2 IA, as indicated in chain lines. The operation or arrangement is, in all essentials, equivalent to that described with reference to Figs. 1, 2 and 3. The arrangement may,

0 however, be such that the arm l9 still engages and exerts spring pressure outwardly upon the davit 6 when it is in its extreme outboard position bearing on the support ZiA, such spring pressure serving to hold the davit against inboard surge and increasing its stability.

In the embodiment shown in Figs. 5 and the davits 8 are fixed each to its own shaft i, which shafts I are mounted. for rotation in bearings in the respective deck fittings 8. end of each shaft 1 is non-rotationally coupled, by a splined or keyed coupling 22 to the adjacent free end of one of a pair of torsion rods 2c, the other ends of which are anchored against rotation in the respective deck fittings 8. The outboard position of each davit 6 is indicated in full lines in Figs. 5 and 6 andthe inboard position is shown in chain lines in Fig. 6. Movement inboard throughout this range has the effect of arming the rods 26 ready for the next outboard lufling movement.

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

1. In aships davit assembly having a pair of spaced lufiing-davits each pivotally mounted in a fixed bracket for movement in a vertical plane between inboard and outboard positions through a top dead centre position, a pair of horizontal torsion rods each anchored at one of its ends to one of said brackets and journalled at its opposite end in the other bracket, a lever secured upon each rodadjacent each journalled end and extending radially "therefrom, and a lug on each davit for engaging saidlever, said levers being secured upon said rods so that when the rods are unarmed the levers extend in an outboard direction, whereby they impel the davits outwardly beyondtheir top dead centre position.

2. In a ships davit assembly the combination of a pair of spaced luffing davit arms, a pair of fixed mountingbrackets' for said davit arms, a pair of shafts secured'one to each davit arm and a bearing in each bracket for one of said shafts, which bearings pivotally mount said davit arms for movement in vertical planes between inboard and outboard positions'through top dead centre, a pair of horizontal torsion rods each anchored at one end to one of the brackets and secured at its other end to one of said shafts, said torsion rods, when the davit arms are in the extreme inboard positions, being armed so as to impel said davit arms outwardly beyond top dead (centre.

3. A davit construction comprising a first and second bracket, a first davit arm mounted in the first bracket for swinging movement from an inboard position to an outboardboat launching position, a second davit arm mounted in said second bracket for swinging movement from an inboard. position to an outboard boat launching position, a first torsion rod secured at one end to said first bracket for preventing rotation of The inner "the other end of said second torsion rod connesting said second torsion rod to said first davit arm for urging said first davit arm outwardly from its inboard position.

4. A davit construction for ships boats comprising a pair of brackets for mounting on a ship in spaced relation adjacent the side of the ship, a davit arm mounted in each bracket for pivotal movement from an inboard position to an outboard boat launching position, a torsion -rod mounted against rotationin each bracket and extending toward the other bracket, means on the other end of each torsion rod connecting the torsion rod that is fixed to one bracket to the davit arm that is pivotally mounted on the other bracket whereby the reaction of the one davit arm is taken by the bracket arm supporting the other davit arm.

5. A ship davit comprisingbrackets mounted on a ship, a davit arm pivotally mounted on each of said brackets for movement from. an inboard position to an outboardlaunching position, spring means supported on eachbracket for taking the reaction on its bracket and delivering the resilient force to the davit arm of the other bracket.

6. A ship davit comprising a pair of brackets mounted on a ship, a shaft pivotally mounted in each bracket, a davit arm fixed on each shaft extending radially for swinging .movement, a

pair of torsion rods each-havingone end fixed on one bracket and extending toward the other bracket, the other end of each torsion rod being coupled to the davit shaft on the other bracket 5 whereby each davit arm is urged outwardly from its inner position to itsoutboard position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name- ,7 Da e 1,190,046 Tjader July 4, 1916 1,799,847 Hall Apr. '7, 1931 1,925,945 Zielinski et a1. Sept. .1933 2,038,233 O-ppenheimv Apr. 21, 1936 2,041,539 Gaultier May 19, 1936 2,542,363 Sarnac Feb. 20, 1951 FOREIGN PATENTS Number Country Date 19,341 Great Britain A. D. 1911

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