US955130A - Ship elevator, cradle, and dock. - Google Patents

Description

E. L. BURWELL. SHIP ELEVATOR, CRADLE, AND DOCK. APPLICATION FILED APR. 14, 1909.

Patented Apr. 19, 1910.

4 SHEETS-SHEET l.

E. L. BURWBLL. SHIP ELEVATOR, CRADLE, AND DOGK.. APPLICATION P'ILED APE.14, 1909.

4 SHEETS-SHEET 2.

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ANDREW I:v GRAHAM 50. PNOTO-UYNOGRAPNERS WASHINGTON. DV (1 E. L. BURWELL.

SHIP ELEVATOR, CRADLE, AND DOGK.

APPLICATION PILED.APR.14, 1909. Q55 1 3,0 Patented Apr. 19, 1910.

4 SHEETS-SHEET 3.

E. L. BURWELL.

SHIP ELEVATOR, CRADLE, AND DOCK.

APPLICATION FILED APR. 14, 1909.

Patented Apr. 19, 1910.

4 SHEETSSHEET 4.

ANDREW B GRAHAM 00 FNDTO-LYTHOGRAPHERS. wAsmNe'mN. u. c

NET

STATS EDWARD L. BURWELL, OF WINCHESTER, MASSACHUSETTS.

SHIP ELEVATOR, CRADLE, AND DOCK.

Specification of Letters Patent.

Patented Apr. 19, 1910.

Application filed April 14, 1909. Serial No. 489,930.

To all whom it may concern:

Be it known that I, EDWARD L. BURWELL, a citizen of the United States, and resident of \Vinchester, county of Middlesex, State of Massachusetts, have invented an Imrovement in Ship Elevators, Cradles, and l ocks, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention applies to marine railways in general, and it has for its object the production of novel means for docking, cradling and elevating a ship or other vessel from the dock to the land, whereby the vessel may be moved bodily to another point for examination, repairs, etc.

My invention is designed for handling vessels of any size, up to the largest, with great facility at a relatively small expenditure of power, and wlth entire safety to the vessel and contents, and the capacity of an apparatus embodying my invention depends wholly upon the requirements of any particular locality.

In its general features my invention comprehends a dock or basin so located as to have suificicnt depth of water to float a vessel at low tide, in which dock or basin is installed an elevator of adequate dimensions and strength to support and raise a vessel, and her cargo if necessary, from her position afloat in the dock, the elevator having movable upon it longitudinally a cradle of special construction. This cradle is arranged to travel upon a series of tracks on the elevator platform, and has mounted upon it means adapted to cooperate with the sides and bilges of the vessel to sustain the latter in upright position on suitable keelblocks when the cradle and elevator are lifted to remove the vessel from the water. The weight of the elevator and cradle is compensated or counterbalanced by suitable weights, and the additional load or weight of the vessel and her contents is taken care of by a system of weight units so applied to the elevator and the parts carried thereby as to render the elevation thereof a very simple matter, as will appear hereinafter. As an additional elevating means I prefer to employ hydraulic or other power, applied to the elevator from beneath as herein shown, whereby the raising and lowering of the elevator and parts thereon can be controlled with great accuracy and very readily.

When the properly cradled vessel has been raised upon the elevator to the shore level the cradle can be run ofi from the elevator tracks either directly to a corresponding set of tracks on shore, or onto a platform-car of suitable construction, arranged to run on fixed tracks to any suitable destination. The arrangement of shore tracks may be varied in many ways, as will be obvious, such arrangement depending upon the desired disposition of the vessel after it has been elevated from the dock to the proper level for removal from the elevator.

The various novel features of my invention will be fullydescribed in the subjoined specification and particularly pointed out in the following claims.

Figure 1 is a view in elevation of an apparatus embodying my present invention, viewed from the inlet or entrance end of the dock or basin and showing the elevator and cradle in readiness to be raised, a vessel in outline being shown on the cradle and held in upright position thereon; Fig. 2 is a top plan view of the apparatus shown in Fig. 1, the sides and inner end of the dock being broken off to save space; Fig. 3 is an enlarged end elevation of the cradle and the means thereon for supporting the vessel in upright position, the supporting means at one side of the vessel being shown in operative position, while the supporting means on the opposite side is in inoperative position; Fig. 4 is a detail in side elevation and enlarged of two of the elevator lifting units, to more clearly show their construction; Fig. 5 is a top plan view thereof; Fig. 6 is a detail of a brake mechanism for regulating the vertical movement of the elevator; Fig. 7 is a view similar to Fig. 3, but showing a diiferent form of support on the cradle for cooperating with the vessel; Fig. 8 is a detail view of the lower part of one of the flexible members or slings adapted to engage the under-body of the vessel.

Referring to Figs. 1 and 2, I have shown a preferably rectangular dock A inclosed on two of its sides by a concrete or other suitable strong and solid structure as at A, the inner end of the dock or basin being closed by a transverse wall A The outer end of the dock or basin is open, and the floor thereof is at such a level, and the dock is so located, that at low tide a vessel may be floated into the dock. The particular con struction of the dock or its dimensions are of no particular moment so far as my invention is concerned, the dock being made of the proper dimensions to admit a vessel of large or small size. Within the dock and vertically movable therein 1 install an elevator of suitable dimensions and strength, and as herein shown the elevator in general comprises a platform E stiffened and braced at E as may be necessary to secure the requisite rigidity and strength, it being understood that the elevator must be capable of sustaining and lifting a cradle and a vessel on the cradle. Suitable guide-rolls E l and 2, are carried by the elevator to travel along the vertical side walls of the dock or basin, and as shown in Fig. 2, I prefer to have a series of such guiderolls at each side of the elevator. Longi tudinal ails E are fixed on the elevator platform D, said rails running from end to end of the platform and adapted to register with corresponding rails leading from the inner end of the dock when the elevator platform is raised to its discharging height. Fixed stops E are secured in the side walls A to overhang the sides of and engage the elevator platform when at discharging level, to prevent further upward movement thereof. Upon the series of parallel tracks E on the elevator, I mount a cradle shown separately in Fig. 8, the cradle being built of structural steel or other desired material, suitably braced and stiffened in various di rections, and comprising in end elevation a truss consisting of a horizontal member C, and upper inclined members C, the bottom member being provided with series of truck wheels C to travel on the tracks F and A". Along the central line of the cradle I provide keel-blocks, as c F 3, upon which the keel V of a vessel is to rest, the hull of a vessel being indicated at V in Figs. 1, 2, 3 and 7. l have mounted upon the cradle two opposed series of supports arranged on opposite sides of the line of heelblocks, and in Figs. 1, 2 and 3, each support consists of a tower-like structure D, preferably built of steel and suitably braced and having its base D provided with wheels (Z arranged to travel on tracks (Z laid upon the sloping members C of the cradle, right angles to the length of the latter, as clearly shown in Figs. 2' and 3. As the several sets of tracks incline outwardly and downwardly from the center of the cradle, the upright supports D will tend to move outward to aid the sides of the cradle, and they may be stopped or locked at different points along their respective paths of movement in any suitable manner. Herein, referring to Fig. 3, 1 have shown the base of support: as provided with a locking dog (Z arranged to cooperate with a rack cl see Fig. 2 ar 'anged adjacent a pair of tracks or rails cl. The supports D extend upward from the cradle high enough to have their upper ends well above the upper deck of the largest vessel, which may be handled by a given structure, and these supports are also of sufficient height that their upper ends will always be above the water level, indicated at L, Fig. 1, no matter if the elevator is atits lowest posit-ion. On a suitable platform D on the top of each support, I provide a power mechanism indicated in general. at M, and preferably electric power will be advised on account of the great convenience thereof, and its ready means of installation. Along the inner faces of each support, I

prefer to provide a series of contact rolls a one or more of which may be brought into engagement with the sides of a vessel when the supports are in their operative position. I also provide guide sheave a? on each support over which travels a flexible member or sling d attached at its lower inner end to the cradle adjacent its center line, and if convenient to the keel-blocks c, as herein shown. Each one of these slings (Z is carried upward from the guide sheaves (7 to the power mechanism M which latter will include a suitable winding drum by means of which the sling may be drawn taut.

Referring to the right hand support D in Fig. 3, it will be seen that it is in inoperative position, and that its sling d hangs slack, the support D being some distance from the side of the vessel V. N ow by operating the mechanism M, the sling d is gradually tightened and as it is tightened it will cause the support to travel inward and up along rails (Z until the sling is drawn tant in engagement with the bilge of the vessel, and one or more of the rolls (Z will be brought into supporting engagement with the sides of the vessel, as shown at the left in Fig. where the support and its sling are shown as properly cooperating with the vessel to hold the latter in upright position.

In Fig. l and also in Fig. 2 the several supports D are shown as properly cooperating with the vessel to support the same in an upright position on the cradle and by aranging a sufficient number of supports and providing for their requisite strength a vessel of any size, with or without a cargo, will be promptly, securely and safely held in upright position on the cradle, even after the elevator has raised the latter and the vcsse out of the water in the dock.

lslanifestly the dead weight of the ele vator, the cradle thereon, and the supports will be large if the plantis designed to handle large vessels, and I ave compensated for or counterbalanced the dead weight of the elevator and cradle, as will be presently explained.

Un the dock at each side thereof, 1 provide a superstructure of any suitable character and construction, and comprising essentially vertical members G and outwardly and downwardly inclined members G, which latter are cross braced at g, Fig. 2, to give-the necessary rigidity, the members G being shown as arranged in pairs, see Fig. 2, and at their lower ends entering chambers A in the structure of the dock. The superstructure is provided with guidesheaves 9 over which are led counterbalancing cables g secured at their lower ends to the sides of the elevator, the upper ends of the said cables having attached weights G, see Fig. 1, the sheaves being located high enough on the superstructures so that when the elevator is in its highest position, there will be ample room for the travel of the weights G These counterbalancing weights in the aggregate are sufficiently heavy to practically counterbalance the dead weight of the elevator, cradle and supports thereon, so that when the cradle is empty the elevator can be raised or lowered with a relatively slight expenditure of power. At the top of each superstructure, 1 have mounted in suitable bearings G a heavy horizontal shaft G the two shafts being arranged in parallelism, Figs. 1 and 9., above and near the plane of each side wall of the dock. Each shaft has rigidly attached to it a series of heavy sheaves G and as shown in Fig. 2, each sheave is located midway between the adjacent pair of inclined members G, the latter acting as guide-ways for gravity actuated lifting units to be hereinafter described. Strong chains or cables G are attached to the elevator platform and are carried up around the sheaves G and outward and downward therefrom, as best shown in Fig. 1, and a lifting unit 1V is suitably attached to the free end of each of such lifting cables G By inspecting Fig. 2, it will be seen that 1 have shown three sheaves GR on each of the shafts G for convenience, but it is to be understood that I may use any suitable number of sheaves and lifting cables according to the desired capacity for the dock and the probable weight to be raised by the elevator. These gravity-actuated lifting units may be variously constructed, provided they are arranged to travel upon the inclined supporting members G of the superstructure and are relatively compact when compared with weight. Herein Thave shown them as box-like in structure, in practice made of iron or steel, and provided with suitable wheels 20 to travel upon the guideways provided by the members G, and save that preferably the lifting cables G may have each a permanently attached lifting unit TV, all of the units are substantially alike. For convenience, however, the other units are indicated by W in the drawings, and the bottom of each is shown in Fig. a as provided with a hook to, while coupling hooks 4.0 on the sides and upper end of the body of each unit are adapted to engage lugs 10 on the sides and at the lower end of the body of the next unit ahead. As shown in Figs. 1 and 4: the front and rear ends of the body are vertical, and the body is closed at the top, with a hopper-like inlet to for the introduction of water or other heavy body, and a valved outlet e0 is provided near the bottom and rear or lower end of the body, by which the contents if liquid can be discharged.

Any suitable coupling device may be used for connecting one unit with another, in a series or train of varying numbers, and it will be understood that preferably the separate units WV are drawn up the inclined guide-ways G and coupled onto one another and to the units W permanently attached to the lifting cables, until a sufficient number of units acting cumulatively will be sufficient to raise the elevator and its load. If tankcar units are employed, such as illustrated herein, they may be connected in series with the lifting cables while the elevator is at its lowest point, and then filled with water by means of suitable filling nozzles N connected with standpipes N carried alongside the guide-ways G, the nozzles overhanging the latter and properly spaced to empty into the hopper-like inlets 10 By this arrangement the empty unit-s are hauled up into position, coupled together, and then filled or loaded to bring them up to weight, and a very uniform lifting action will thereby be exerted upon the elevator through all the lifting cables G On the other hand the units may be filled before they are hauled up to position, or the permanent weight of each unit may be constant, as would be the case were the box-bodies herein shown filled with sand, slag, etc. In either case the power required for positioning the units need be but little greater than that sufficient to haul a single unit up the inclined guide-way, and in Fig. 1 I have shown one arrangement of hauling mechanism.

On the upper end of each guide-way G I mount a sheave 10, over which is carried a wire rope or cable w having at its free end a loop or eye wa Fig. 4, adapted to engage the hook to on one of the units W The other end of the cable is brought down to an electric or other hoisting engine TV on the top of the dock structure, by means of which the units are drawn up out of the chambers or recesses A into position to be connected with the elevator-lifting cables G By means of a relatively low-powered hoisting mechanism one after another of the lifting units is drawn up into operative position and connected with its proper cable, as shown in the drawings, until the combined weight of all the units is substantially sufiicient to raise the load on the counterbalanced elevator and cradle, such parts being shown in Fig. 1 in readiness to be raised. The ele vator and cradle being counterbalanced the principal function of the lifting means, to wit: the cumulativelyacting gravity actuated units, is to compensate for the weight of and lift the vessel and contents. While this lifting could be performed wholly by the units, by adding a sufiicient number, I prefer to use in connection therewith auxiliary lifting means, such as a piston 72, Fig. 1, vertically movable in a cylinder 79 embed ded in the bottom of the dock, and controlled by a hydraulic or pneumatic motor P. In practice, with large elevators a munber of these auxiliary lifting devices would be employed, and as the entire load to be lifted is practically counterbalanced a relatively slight expenditure of power is required in the auxiliary means.

. ly the apparatus described the elevator is raised to bring its rails or tracks E to the level of the tracks A at the top of the dock, and when so raised the cradle and the vessel supported thereon can be run elf onto the tracks IV and conveyed to any desired point, in a manner similar to that employed in marine railways at present. Inasmuch as the transportation of the cradle and the vessel supported thereon may be effected in various ways after the vessel has been raised from the deck I have only shown one form, viz: the tracks A as sutliciently illustrative of such transportation.

The auxiliary lifting means is brought into action when the vessel is afloat in the dock above the cradle, for by such means the elevator and cradle are raised from their lowest position into place for the cradle to receive upon it the vessel V, as shown in Fig. 1.

lt desirable to have means for readily controlling the vertical movement of the loaded elevator, and for this purpose I have mounted ln'ake-sheaves 2, Figs. 2 and 6, on the overhead shafts G embraced by brake or friction shoes 3, fast at one end and at the other ends connected with levers 4 operated by compressed air, hydraulic or other brake cylinders 5, preferably connected in practice with a central control station, so that the rotation of the shafts G may be easily and properly governed.

The flexible members or slings by which the under-body of the vessel is supported mav be divided at their lower or inner ends into a plurality of members d, Fig. 8, con- 11 cted at their lower ends tothe keel-blocks (1 and converging to common connection rZ", so as to present a fairshaped sling. This is of advantage as thereby the action of each sling is distributed for a considerable distance along the bilges of the vessel, to better and more securely support the latter in upright position on the cradle.

Inasmuch as the adjustment and movement of the upright supports D on the eradle, Fig. 3, will be effected while the lower portions of such supports are under water, I have provided the locking dogs or devices (Z with releasing links or rods (Z which extend up to the platform I) and from which the dogs are operated to release them from the racks (P, Fig. 2.

Referring to Fig. 7 I have shown a modified form of supporting means on the cradle, wherein upright columns or towers ll are fixedly attached to the cradle at intervals along its sides, each tower having a platform 1 with a hoisting motor P thereon. A derrick-arm R is pivoted at its feet at R at the base of each tower and is inclined toward the center of the cradle, and adjusted as to its inclination by suitable tackle It. Slings (N, such as shown in Fig. 8, are provided, the connections d thereof having each an attached block J, through which is reeved a cable (W passing over sheaves (Z on the arm R and led thence to the motor R. After proper adjustment of the supporting arms R according to the width of the vessel the slack of the cables (5 is taken up and the slings (W are thereby drawn up taut around the sides and bilges of the vessel, as in Fig. 7, and the vessel is thereby securely held in upright position on the cradle, and thereafter it can be lifted out of the deck by the elevator as has been described.

The operation of the apparatus as a whole will be manifest from the detailed description previously set forth and need not be repeated, but it may be stated that when a vessel is to be returned to the dock and again floated the cradle supporting the vessel will be run onto the lifted elevator, and the lat ter will be then lowered. Such lowering is effected by disconnecting a sufficient numb r of the lifting units from the lifting cables to enable the weight of the vessel and contents to cause the elevator to descend, and when the vessel is at flotation height in the water in the deck the cradle supports are cast off, and then the elevator and cradle are again made to descend far enough to allow the vessel to clear the cradle. The vessel can then be floated out of the dock and the apparatus is in readiness for the next vessel to enter.

lVhile the control of the elevator in its vertical movement can be attained by the addition or removal of the lifting units, thus utilizing gravity alone, it will in most cases probably be preferable to employ in connection therewith the auxiliary lifting means hereinbefore referred to.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is 1. In apparatus of the class described, an elevator, a cradle longitudinally movable thereon, means to counterbalance the weight of the elevator and cradle, means mounted on the cradle to engage and support a vessel and maintain it upright on the cradle, and a system of lifting weights adapted to be connected individually with and to act cumulatively upon the elevator and the load thereon, to raise the same to the desired level.

2. In apparatus of the class described, a counterbalanced elevator and cradle, the latter movable longitudinally on the former, means on the cradle laterally movable to ward and from a vessel thereon, to maintain the vessel upright on the cradle, and means to govern the elevation and descent of the elevator and its load, said means including a system of weight units adapted to be brought singly into cooperation with the elevator, to act cumulatively thereupon.

3. In apparatus of the class described, an elevator, a cradle longitudinally movable thereon and provided with means to engage and support in upright position a vessel on the cradle, and means to raise the elevator and its load, said means including a plurality of weight units adapted to be brought singly into cooperation with the elevator to act cumulatively thereupon.

4;. In apparatus of the class described, an elevator, means carried thereby to support a vessel in upright position, and means to raise the elevator and its load, said means including a series of overhead lifting cables connected with the elevator, and weight units adapted to be attached one after another in series to said cables to act cumulatively upon and lift the elevator and its load.

5. In apparatus of the class described, an elevator, means carried thereby to support a vessel in upright position, and means to raise the elevator and its load, said means including a plurality of series of separable weight units adapted to be brought singly into cooperation with the elevator to act cumulatively thereupon.

6. In apparatus of the class described, an elevator, means carried thereby to support a vessel in upright position, and means to raise the elevator and its load, said means including a plurality of separate weight units, and a device to bring such units one after an.- other into cooperation with and to act onmulatively upon the elevator.

7. In apparatus of the class described, a dock or basin into which a vessel can be floated, an elevator vertically movable in the dock, a cradle on the elevator to support and maintain upright a vessel thereon, and means to raise the elevator and its load to a predetermined height, said means including a plurality of separate lifting weights adapted to be brought in varying number into cooperation with the elevator to act cumulatively upon and lift the elevator and its load.

8. In apparatus of the class described, a

dock or basin 1nto which a vessel can be floated, an elevator vertically movable in the dock, a cradle on the elevator to support and maintain upright a vessel thereon, counterbalancing means for the elevator and cradle, and means to raise the elevator and its load to a predetermined height, said means including a plurality of separate lifting weights adapted to be brought in varying number into cooperation. with the elevator to act cumulatively upon and lift the elevator and its load.

9. In apparatus of the class described, a dock or basin into which a vessel can be floated, an elevator vertically movable in the dock, a cradle on the elevator to support and maintain upright a vessel thereon, and means to raise the elevator and its load to a predetermined height, said means including a plurality of gravity-actuated lifting units adapted to be operatively connected in varying number with the elevator to act cumulatively thereupon.

10. In apparatus of the class described, a dock or basin for the reception of a vessel, an elevator in said dock and vertically movable therein, a cradle mounted on the elevator and adapted to be moved longitudinally thereof, means on the cradle to sustain a vessel in upright position thereon, means to counterbalance the weight of the elevator and cradle, an over-head shaft above and at each side of the dock, a series of sheaves on each shaft, an inclined track leading downward from each sheave, lifting cables connected with the elevator and carried up over the sheaves, a series of lifting units adapted to travel on each track and to be connected in varying number with the upper end of each cable, and means to raise said lifting units singly to be connected with a cable.

11. In apparatus of the class described, a dock or basin for the reception of a vessel, an elevator in said dock and vertically movable therein, a cradle mounted on the elevator and adapted to be moved longitudinally thereof, means on the cradle to sustain a vessel in upright position thereon, means to counterbalance the weight of the elevator and cradle, an over-head shaft above and at each side of the dock, a series of sheaves on each shaft, lifting cables connected with the elevator and carried up over the sheaves, and means to connect lifting weights in requisite amount to the free ends of the cables to eifect lifting of the elevator and its load by cumulative action of the weights.

12. In apparatus of the class described, a dock or basin for the reception of a vessel, an elevator in said dock and vertically movable therein, a cradle mounted on the elevator and adapted to be moved longitudinally thereof, means on the cradle to sustain a vessel in upright position thereon, counterbalancing means for the dead weight of elevator and cradle, a series of sheaves rotatably supported above the dock at each side thereof, lifting cables attached to the elevator and carried up over said sheaves, a plurality of separate lifting units adapt-ed to be coupled together in series and connected with the free en ls of said cables, to act cumulatively upon and raise the elevator and its load, and means to bring the lifting units into cooperation with the cables.

13. In apparatus of the class described, a dock into which a vessel may be floated, a vertically movable elevator in the dock and provided with longitudinal rails, a cradle provided with trucks to travel on the rails and move longitudinally off the elevator, means on the cradle to support a vessel thereon, a superstructure at each side of the dock and each provided with a series of sheaves, lifting cables attached to the sides of the elevator and carried up over the sheaves, downwardly and outwardly inclined guideways adjacent each sheave and mounted on the superstructure, separate gravity acting lifting units adapted to trave on the guideviays and to be connected in varying number with the upper end of each lifting cable whereby the cumulative action of all of the connected units will operate to lift the elevator and its load, means to bring said units into cooperation with the lifting cables, and brake mechanism to control the lifting action.

l l. In apparatus of the class described, a dock into which a vessel may be floated, a vertically movable elevator in said deck, a cradle longitudinally movable on the elevator and provided with means to sustain a vessel in upright position, counterbalai'icing means for the dead weight of the elevator and cradle, parallel over-head shafts supported above the dock at each side thereof, a series of sheaves fast on each shaft, lifting cables attached to the sides of the elevator and carried up over the sheaves, and means to apply to the upper free end of each cable a variable lifting weight, and brake mechanism to control the rotation of the over head shafts during vertical movement of the elevator and its load.

15. In apparatus of the class described, a dock into which a vessel may be floated, an elevator vertically movable in the dock, a cradle carried by the elevator and provided. with means to sustain a vessel in upright position on the cradle, parallel over-head shafts mounted above and at the sides of the dock and each provided with a series of sheaves, lifting cables attached to the sides of the elevator and carried upward over the sheaves, downwardly and outwardly inclined guideways adjacent said sheaves, separable weight units adapted to travel along the guideways and to be connected in varying number with the upper end of each lifting cable, and means to raise said weight I l i l i l l I l l i l i ,l l l l J l l l I l units individually and operatively connect them with the cables, the cumulative action of the units connected with each cable operating to overcome the weight of the eleva tor and its load.

16. In apparatus of the class described, a dock into which a vessel may be floated, an elevator vertically movable in the dock, a cradle carried by the elevator and provided with means to sustain a vessel in upright position on the cradle, parallel over-head shafts mounted above and at the sides of the dock, and each provided with a series of sheaves, lifting cables attached. to the sides of the elevator and carried upward over the sheaves, downwardly and outwardly inclined guide ways adjacent said sheaves, separable weight units adapted to travel along the guide 'ays and to be connected in varying number with the upper end of each lifting cable, and means to raise said weight units individually and operativcly connect them with the cables,

the cumulative action of the units connected with each cable operating to overcome the wei ht of the elevator and its load, combined with an auxiliary lifting device to act upon the elevator and its load independently of the action of said weight units.

17. In apparatus of the class described, a dock into which a vessel may be floated, an elevator vertically movable in said dock, means to guide the elevator in such movement, stops to limit the rise of the elevator, a cradle carried by the elevator and adapted to be moved therefrom when the elevator is raised, means on the cradle to sustain a vessel in upright position thereon, lifting means to raise the elevator and bring the cradle into position beneath a vessel floating in the dock, and other means to act upon and raise the elevator and its load to the desired level, said other means including a plurality of gravity actuated lifting members adapted to be operatively connected in varying number with the elevator, toe cumulative action of said lifting member serving to lift the elevator and its lead.

18. In apparatus of the class described, a dock into which a vessel may be floated, an elevator rtically movable in the dock, a cradle longitudinally movable on the elevator and provided with means to sustain a vessel in upright position on the cradle, counterbalancing means for the dead weight of the elevator and cradle, lifting cables attached to the elevator, over-head sheaves around which the said cables are carried, downwardly and outwardly inclined tracks adjacent the sheaves, gravity actuated lifting members adapted to be connected with the free end of each cable, each of said members having a hollow body and wheels to travel on the tracks, means to fill the bodies of said members with a weighty material,

and power mechanism adapted to be temllo porarily attached to one after another of said gravity actuated members to raise them along the tracks into position to be operatively connected with a cable.

19. In apparatus of the class described, a cradle having upright supports arranged in two opposed series, means to move the supports toward and from a vessel between the two series, and flexible members connecting said supports and the cradle along the longitudinal center thereof, to contact with the sides and bilges of a vessel and maintain the latter in upright position.

20. In apparatus of the class described, a cradle having transverse series of tracks sloping from the center toward the sides of the cradle, supports movable on said tracks toward and from the center line of the cradle, said supports being arranged in two opposed series to receive a vessel between them, flexible members connecting the said supports and the center of the cradle, and means to tighten said members, whereby the supports will be moved inward into engage ment with the sides of the vessel and the flexible members will contact with and conform to the bilges thereof.

21. In apparatus of the class described, a cradle having a central row of keel-blocks, a series of upright supports on the cradle at opposite sides of the keel-blocks, flexible members attached at their lower ends to the keel-blocks and connected at their other ends with the supports, and means to draw said members taut in engagement with the bilges of a vessel resting on the keel-blocks, to maintain the vessel in upright position on the cradle.

22. In apparatus of the class described, a cradle, opposite series of upright supports mounted thereon and extending longitudinally of the cradle, said supports being movable toward and from a vessel resting on the cradle between the two series, slings attached to the cradle adjacent its center line and leading therefrom to the supports,

and means to draw said members taut against the underbody of the vessel to serve as supporting slings therefor and maintain it upright on the cradle.

28. In apparatus of the class described, a cradle, opposite series of upright supports mounted thereon and extending longitudinally of the cradle, said supports being individually adjustable with relation to the center line of the cradle, a sling connecting each support and the cradle, each sling comprising a plurality of members attached to the cradle adjacent its center line and converging to a common connection at their outer ends, and means to draw taut the slings about the underbody of a vessel.

24L. In apparatus of the class described, a cradle, upright supports thereon in two series on opposite sides of its center line and movable toward and from such center line, a sling connected with each support and extended downward and inward therefrom, each sling having a plurality of diverging members at its lower end fixedly attached to the cradle adjacent its longitudinal center, and means to draw the slings taut about the underbody of a vessel on the cradle.

25. In apparatus of the class described, a cradle, upright supports thereon in two series on opposite sides of its center line, transverse tracks on which the supports are movable, slings attached to the cradle adjacent its center line and leading therefrom to the supports, and means to tighten the slings and thereby draw them and the supports into supporting engagement with a vessel on the cradle.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

EDWARD L. BURIVELL.

Witnesses JOHN C. EDUARDS, THOMAS J. DRUMMOND.

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