US2260772A - Davit - Google Patents

Description

Oct. 28, 194i.. A. w. coATS ETAL DAYIT Ijiied June* 1, 1938 s sheeis-snee; s

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Patented Oct. 28, 1941 UNITED-j STATE oAvrr Y Alfred Coates, .vBayonneQNf J., and Robert y Wilson, dece'ased late of Brooklyn, N.A Y., `by f y Emily Wilson, administratrix, `Brooklyn, N. Y.

Application June 1, 19378;SerialjNo. 211,222 l claims.

Our present invention relates to davits,"and more particularly to davits designed lfor marine serviceV` although they may be used for hoisting in' general :as Well. i l The principal `object 'of our invention" is the production of' a davit and controlling u'means wherein `the 4davit arm is actuated largely by gravity, the weight of the boat Aand its load.

- Another Objectis the production of a davit so designed and controlled asto vpermit of installations in'ships orsimilar places where space isfa 'considerable factor, and yet which will perm-it of positive operation even under the most severe conditions imposed bythe listing ofthe ship, storms and the like.4 l

y lA vstill further object? is the production of la .davit of novel design whereinV the davit arm'is so-vmounted as `to produce a yconstantly'shifting support for the boat kduring-,the operation of said davit, the result being a more positive control of thefmovement of the boat within smaller limits of .time and space. I'he many additional objects and advantages of our invention will readily be understood by those skilled lin the' artV and particularly after a study ofv the following 'specification and the attached `dravs'ingswherein: l I f Figure 1 is an end elevation, partly in section, of `one of` our' davits as mounted upon a ship deck;

Figure 2 a front elevation thereof; :Figure' a modification offa davit arm;

Figure 4 a perspective view of a latch for: securing the davit arm in itsv idle position;

Figure 5 a cross section of a boatv securing means; I

lFigure 6 a front elevation thereof.;` y Figure 7 a front elevation, partly insection, of a winch;

, Figure 8 an end View thereof; and

Figure v9 a detailed View of one of the "winch Clutch members. v Referring to the drawings the numeral Illindicates, generally, a support which is secured to the deck of a vessel II, in a position as near the edgek thereof as possible. In the form shown the supports are arranged inpairs and each consists of a horizontal member I2, a vertical member I3, and an' inclined track member I4. These' three members are secured together by bolts, welding or otherwise, and may be formed ofv channelled or flanged sections of steel, iron or other suitable materials. Spacing members I5 are' used at periodic points to hold the paired supports in correct position and alignment. I

,V (cil 9-22) Y,

"ing

The dava varm ls. in me fcrm umstfated; is

constructed of Ia` pair of steel plates I'I and I8,v 'held in spaced" relation to each other :by spacing vmembers I9'. The davit arm yconsists of av body 'portion 20', Yan arcuate shaped upper' end: portion 'ZIand a lower 'end portion 22 which tapers't'ola ybearing23. Y'A pivot vpln'2ll,`mounted in a'b-earl23, pivot-'allysecures theidavit arm to'apair of links 25 which are in turn pivotally secured to the horizontal member I 2l of the V`V`support. The body portion y2|) of the davt is provided with bearings 26 .for the reception of a "shaft"'21 u ponrwhich are mounted a pair of flangedroll'r's 28 fandwhiehl atcertain stages of the movement of the davit armengagethe inclined track M of the supporti." In Figure 3' weillustrate afm'odiedform of mounting Afor' the rollers lZwherein a pair of plates29 are pivotally Jsecured to "the davit arm and in which a Ashaft 21" vis' mounted and which rcarries the rollers 28. Aj stop 3'0 'is secured between the plates which, when the davit armswings forward, engages the davit arm and acts. as -a support therefor.' 'While' we have ilf lustrated vand described two different forms of davitarms having two setsofrollers for engage'- nient with theltrck, it is to be understoodlwe may,r ii desired, use only one` set'which will always be in 'Contact with the track, ther only difference in jthe operationv of the davit vvarm beingl in the movement of the* davit arm during the initial movement' thereofA and fthe correspondir'lgl vmoi/"e-r The upper end of the davit arrnh'has mounted upon each side thereof pulleys-3I 'over whichf-the hoistingcable is trained.- A hook 32 in the daviwt arm is ar-ranged to engage a bail' oreyelet 3'3f'oarried a block34, and to5aii'0rda support for the load Vimposed upon `the block when the da'vit/v arm is inthefst'owaway period. f f

yThe body of the davitarmalso vcarries a pair of rollers 35 rotatably mounted upon a' shafty 36 journalled in thedavit arm. Thev rollers-35 are in engagement with the-track I4 Yat certainperiods and act both 'as aload support aswell as a guide foithe davit arm duringthe initial periodof movement thereof and until the rollers 2,8 engage the'track. y

In `order to securely sustain the life-boat, during the 'idleperiod or -stowaway period, we proL videa seriesiof blocks 38 'secured 'to the `rdavi't arm I6 and which are design-edto conform tothe contour of the boatat the point of engagement;- We also providea cable`39, which has'at yone e'nd'a clamp II'II for `engagement with they gunwale of the boat, and which is secured at the other 'end to an eyelet 4|. The eyelet has a threaded shank for engagement with a block 42 carried in one end of a latch 43 pivoted to the upright member I3 of the support. A nut 44 having a handle or crank secured thereto, is threaded over the free end of the eyelet 4I and provides a suitable means for tightening and loosening the tension on the cable 39. The opposite end of the latch 43 is arranged to engage a pivoted loop member 45 carried by the davit arm, and when the cable 39 is tensioned by means of the nut 44 the latch and loop prevent the davit arm and boat from moving.

A cable 46 is provided to control the raising and lowering of the boat and has one end thereof secured to a drum 41 of a suitable power hoist 48. Inasmuch as the hoist will of necessity have to be positioned at different points with respect to the davit arms because of the varied design of superstructures of various ships, the cable 46 as :it leaves the hoist will be passed over pulleys or the like (not shown) to a point in the line vwith 'the davit arms. From such point it passes up over a pulley 49 mounted upon the upper end of the membervl3 of the support, and from there over one of the pulleys 3I to the block 34. From Vthe block it passes over the opposite pulley 3I and -down to the upper end of the member I3 where itis secured.

In Figures '1, 8 and 9, of the drawings, we illustrate a preferred form of winch and one particularly adapted to a davit unit of the type disclosed. The drum 41, over which the cable 46 is trained, is mounted upon a shaft 50 which is journalled at each end in a main frame I of the winch. Al worm gear 52 is mounted upon the shaft'50 and, meshes with a worm 53 secured to one end of a shaft 54 mounted in a bearing 55 secured tothe main frame 5I 'Ihe opposite end of the shaft 54 has mounted thereon a mitregear 56 which meshes wifh a similar gear 51 loosely mounted upon a shaft 58 rotatably :mounted in bearings 59 carried by the frame 5I. 'The shaft 58 has its ends projecting through the frame 5| and squared to accommodate a detachr able hand crank. Also mounted upon the shaft 58, Vbut keyed thereto, is a clutch member 60 .whichengages a corresponding clutch member 6IV integrally secured to the mitre-gear 51. The clutch members 60 and 6Ir are machined to al- .low for a large clearance so as to permit of rotary movement therebetween for apurpose later to be described.

A shaft 62 is mounted in the frame 5I parallel -to the shaft 58 and has mounted thereon a gear 63 which is arranged t-o mesh with a gear 64 mounted upon the shaft 50. Like the shaft 58 Athe shaft 62 has its ends projecting through the frame 5I and squared for engagement with a detachable hand crank. A gear 65 is mounted upon the shaft 62 which meshes with a gear 66 mounted upon theshaft 58. f

-An electric motor 61 ismounted in the lower part of the frame and carries apinion 68 which meshes with the gear 64 carried bythe shaft 50.

From the construction just described it will be apparent that we have devised a novel and practical winch which will operate with equal success whether driven by hand or by power. When it is desired to lower the boat, by hand for example, the operator rotates the hand-crank and in turn .the shaft 62, or in case he desires a different gear ratio, he places the crank on the end of shaft 58, either of which causes the gear 64 to rotate and also the mitre gears 56 and 51. The rotation of the shaft 58 and the gear 64 causes the clutch members 60 and 6I to rotate the drum and also the worm wheel 53. If power is used the pinion 68 rotates the gear 64 and the result is the same. It is well known that worms and worm gears may be driven in one direction only. In the design described we employ a worm wheel and worm having such an acute angle between them that no motion of the shaft 50 may be had except in one direction unless `the friction on the worm gear is relieved by rotation of the shaft 58 at the same time. When the power on the shaft 50 is removed, the clutch members, because of the play or clearance between their engaging surfaces, break their contact due to the load on the drum, whereupon the worm and worm gear carry the entire load. In view of the acute angle the friction between the two prevents all movement of the drum until power is again applied. This construction prevents all movement of the drum .in case the power is interrupted by accident or otherwise.

lThe block 34 has a link 15 pivotally mounted in the lower portion thereof for forming a detachable connection with the lifeboat. The link 15 is arranged to be projected through a slot in a plate 16 secured in the end of the boat and to be engaged by apivoted counterbalan'ced latch member 11 which is connected to one end of a pivoted arm 18. A rope or similar means may be connected to the arm 18 and thereby enable the link 15 to be released from a distant portion of the boat.

In operation our davit operates as follows:

Assuming the boat and its control is in the Stowaway position and it is desired to lower the boat, the crew will rstirotate the hand crank 44 which releases the tension on the securing caible 39, the winch willv next be operated, by power or by hand, which will cause the cable 46 to permit the davit arm to move outwardly. The reason for this movement is due to the weight of the boat and the fact the davit arm is never in a position when gravity will not be effective thereon. The initial movement of the davit arm will be lateral until the links25 cause the upper part of the davit arm to move faster than the lower end whichv movement causes the rollers v28 to engage the track I4. At this point the links 25 begin to swing on their pivots which permits the davit arm to continue its outward and downward movement untilthe free end of the davit arm is projected well out over the edge of the deck. Here the further movement of the arm is arrested whereupon the block leaves the hook 32 of the davit arm and it is lowered to the water line with the boat. At this point the counterbalanced arm 18 may be rotated which releases the link 15 Iand the boat freed from the mother ship. To raise a boat the operation is reversed.

Thus it will be seen that we have originated and perfected a novel type of davit and a control therefore, wherein the davit arm is of the oatving gravity actuated type and which at all times is so flexibly mounted as to permit of great movement and still be under the positive control of the operator. It will also be seen that the construction of our controlling mechanism, and particularly the winch, is novel and particularly adapted to operations of this kind.

While we have illustrated and described certain constructions and combinations it is to be clearly understood that other combinations and constructions may be resorted to without depart ing from the spirit andV scope of our invention.

We claim:

1. A davit structure comprising a support adapted to be positioned adjacent the side of the ship and a davit arm mounted thereon for swinging movement from a generally vertical position to a generally horizontal position; said support including a base element and an element formed to provide an upper track surface secured thereto at an acute angle with respect to the base element whereby it is adapted to slope downwardly and outwardly with respect to the ships side, said davit arm including upper and lower portions, pvot means adjacent the lower end of the arm, and fulcrum means positioned intermediate the ends of the arm for unconstrained engagement with and movement along the track surface, said pivot means including a link element pivotally attached to the lower end of the davit arm and pivotally attached to the base element approximately midway between the ends of said base element whereby the upper portion of the davit arm may move outwardly and downwardly under the action of gravity, the length of said link element being such that the distance of outward movement is greater than the distance of downward movement.

2. A davit structure as claimed in claim 1 wherein, with the davit arm in vertical position, the upper arm portion is shaped to project outwardly to such a distance that the center of gravity of a loadsupported thereby lies substantially directly over the pivot in said base element.

3. A davit structure as claimed in claim 1 wherein, with the davit arm in vertical position, the upper arm portion is shaped to project outwardly to a point approximately over the pivot in said base element and wherein said link element projects from `the pivot in the base element inwardly approximately the same distance that the upper arm portion projects outwardly, whereby with the davit arm in said vertical position it stands substantially entirely to one side of said pivot in the base element.

v1. A davit structure as claimed in claim 1 wherein the fulcrum means includes track engaging elements spaced transversely of the arm, each` engaging only the upper surface of the track whereby they may ride over obstructions on the track in their travel therealong.

5. A davit structure as claimed in claim 1 wherein the fulcrum means includes a bar element pivotally attached to the davit arm and wherein fulcrum elements are pivotally attached to opposite ends of the bar element for rolling engagement with the track.

ALFRED W. COATES. EMILY WILSON, Administratri of the Estate of Robert Wilson,

Deceased.

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