US3467263A

US3467263A - Shipboard gantry crane and hoist mechanism therefor

Info

Publication number: US3467263A
Application number: US688815A
Authority: US
Inventors: Raimunds Auzins; Stephen P Yendrich Jr
Original assignee: MORGAN ENG CO
Current assignee: MORGAN ENG CO
Priority date: 1967-12-07
Filing date: 1967-12-07
Publication date: 1969-09-16
Anticipated expiration: 1986-09-16

Description

Sept. 16, 1969 R. AUZINS ET AL SHIPBOARD GANTRY CRANE AND HOIST MECHANISM THEREFOR 7 Sheets-Sheet 2 Filed Dec.

l l l I ll lllilllll INVENTORS. RAIMUNDS 'AUZINS a STEPHEN BJENDRICH, JR.

Sm, J/mdaam 8 Gem Bar/3 ATTORNEYS Sept. 16, 1969 uzms ETAL SHIPBOARD GANTRY CRANE AND HOIST MECHANISM THEREFOR Filed D90. 7, 1967 '7 Sheets-Sheet 5 Fl G.4

INVENTORS.

18h, JR, 3441664. 4. m a @414 ATTORNEYS Sept. 16, 1969 R. AUZINS ETAL 3,467,263

SHIPBOARD GANTRY CRANE AND HOIST MECHANISM THEREFOR Filed Dec. 7, 1987 7 Sheets-Sheet .4

INVENTORS. FIG.- 5 RAiMUNDS AUZINS a STEPHEN P. YENDRlCH, JR.

BY BM, 5%,

JW 8 @am ATTORNEYS Sept. 16, 1969 uzms ETAL SHIPBQARD GANTRY CRANE AND HOIST MECHANISM THEREFOR Filed D80. 7, 1967 7 Sheets-Sheet 5 INVENTORS. RAIMUNDS AUZINS a STEPHEN P. YENDRIC H, JR

Judd/1on8 6am ATTORNEYS Sept. 16, 1969 R. AUZINS ETA!- 3,467,253

SHIPBOARD GANTRY CRANE AND HOIST MECHANISM THEREFOR Filed Dec. 7 1967 7 Sheets-Sheet 6 F I G.- 9

INVENTORS.

RAIMUNDS AUZINS 8| STEPHEN P YENDRICH, JR.

Dir/3044410414, 5mm, J/mdham 8 ain ATTORNEYS Sept. 16, 1969 R. AUZINS ETAL SHIPBOARD GANTRY CRANE AND HOIST MECHANISM THEREFOR Filed Dec. 7, 1967 7 Sheets-Sheet 7 F a-u FlG.- I2

INVENTORS. RAIMUNDS AUZINS 8 STEPHEN F. YENDRICH, JR.

BY SW,

almzm ATTORNEYS United States Patent 3,467,263 SHIPBOARD GANTRY CRANE AND HOIST MECHANISM THEREFOR Rnimunds Auzins, Canton, and Stephen P. Yendrich, Jr.,

Beloit, Ohio, assignors to Morgan Engineering Company, Alliance, Ohio, a corporation of Ohio Filed Dec. 7, 1967, Ser. No. 688,815 Int. Cl. B63b 27/00 US. Cl. 214-15 5 Claims ABSTRACT OF THE DISCLOSURE This disclosure presents a single girder, low-profile shipboard gantry crane for transferring cargo between a dock and a ship. The crane travels on spaced parallel rails located on opposite sides of the ship parallel to the ships longitudinal centerline, and has a cargo handling span or reach formed by a single transverse main girder and at least one hinged outboard cantilever or jib which can be swung upward to a horizontal position over a dock, in end-to-end alignment with the main girder and which, when folded down along side the gantry leg, can be used to help secure the crane to the ships deck structure while the ship is underway. A side running trolley car with a turntable is supported in cantilever fashion at the side of either the single main girder or outboard jib.

Background of the invention This invention relates to gantry cranes and hoist mechanisms therefor, and especially to traveling type shipboard gantry cranes having one or two outboard cantilevers or jibs for use in handling cargo such as shipping containers between a dock or barge and a cargo hold during loading and unloading. More particularly the invention relates to a single girder type shipboard gantry crane having a traveling trolley car which carries a turntable and hoist equipment for lifting and lowering the cargo container.

The use of containerized cargo has received widespread acceptance by the shipping industry in recent years and has led to the design of new types of ships and also to the use of bridge-type traveling gantry cranes carried aboard the ship for loading and unloading thecontainers. Such cranes have been found to be capable of faster, more efficient operation when used in connection with containerized shipping. Generally the cranes travel on rails located on opposite sides of the deck parallel to the ships longitudinal centerline so that the gantry legs span the cargo hatches and the traveling car carried by the transverse bridge of the crane can be positioned to load and unload the cargo containers to and from the cargo holds with its associated hoist equipment. The height of the crane is sufficient to enable the transverse bridge and hoist equipment to clear any obstructions on the deck.

Even more recently ships have been designed to carry both cargo barges and shipping containers. These ships are preferably provided with two gantry cranes, one for handling barges and the other for handling the containers. Both cranes are adapted for travel on the same spaced parallel rails (see e.g. US. Patent No. 3,273,527 to Goldman and US. Patent application Ser. No. 572,052), now Patent No. 3,390,657.

3,467,263 Patented Sept. 16, 1969 Traveling gantry cranes which are carried on board ship for handling shipping containers generally have need for at least one outboard extension or jib, and usually two (one at each side) in order to transfer cargo between the ship and a dock or barge when the ship is in port. However, when the ship is underway, the outboard extension must either be folded downward alongside one of the gantry legs (see e.g. US. Patent No. 3,042,227, to Tantlinger) or retracted inward between the gantry legs (see e.g. US. Patents No. 3,204,780, to Holt et al.; No. 3,077,992 to Bevard, and No. 3,130,840 to Myers et al.) in order to secure the crane during the operation of the ship while underway, particularly in heavy seas.

Usually such cranes are provided with hinged extensions or jibs which may be pivoted between a raised upright position and a lowered or folded position adjacent the gantry leg as shown in Tantlinger. Cranes of this type are frequently used in port facilities as well as on ships for loading and unloading various types of cargo with the hinged extension being adapted for location transversely over a docked ship or vice versa when the crane is located on the ship. The extension or jib in the case of land based cranes must be capable of being swung upward out of its horizontal operating position in order to provide clearance for masts and other ship superstructure when the ship is moving to and from its loading position at the dock.

One major problem encountered in connection with shipboard gantry cranes is that of having a relatively large mass located well above the deck of the ship. This makes the crane difiicult to secure for sea due to its high center of mass or more importantly its large radius of gyration. This also reduces the stability of the ship due to the increased height of the ships center of gravity. Accordingly single girder type gantry cranes are preferable due to their reduced mass.

Most single girder gantry cranes utilize either a hoist carrying trolley on top of the girder with rope falls on each side, or a suspended type trolley which travels beneath the girder suspended below the trolleys rollers which ride for example on flanges at the bottom of the girder. The latter type is undesirable for shipboard use because the height of the girder above the ships deck must be sufiicient to accommodate the trolley beneath it as well as the load being carried and obstructions on the deck.

The top running trolley with rope falls on each side is not suitable for shipboard container cranes, because it is not possible for the containers to get past the gantry legs.

Another drawback of single girder type cranes of the above description is that they generally do not provide sufficient clearance between the cargo load being carried and the gantry leg during movement of the trolley from the outboard extension to the main girder which spans the cargo holds. Normally for this reason, cargo containers must be carried by the crane with the longitudinal centerline of the cargo container perpendicular to the ships longitudinal centerline. The need for this type of loading and unloading seriously reduces the flexibility and versatility of the crane.

Another problem encountered is that of handling assymmetrically loaded containers or in other words containers loaded so that the center of gravity is longitudinally displaced from the geometrical center. If the center of gravity is spaced outwardly relative to the point of suspension of the nearest hoist ropes, the container will tip in the ropes until the center of gravity is vertically aligned with the nearest suspension point. Where such tipping tilts the container very much from its horizontal position, the loading and unloading operation cannot be properly performed. For design purposes, loaded containers having a center of gravity spaced longitudinally from the geometrical center as much as 20% of the length of the container (c.g., 8' for a 40' container) must be accommodated.

The gantry crane and hoist mechanism of the present invention however substantially resolve the problems indicated above and provide other features and advantages not obtainable from the prior art.

Summary of the invention It is among the objects of the invention to provide an improved means for securing a shipboard gantry crane to a ships deck structure when the ship is underway.

Another object is to provide a means for turning cargo containers through at least 90 of arc while being carried by hoist ropes suspended from a traveling trolley car on a single girder shipboard gantry crane and to restrict the twisting of a latch frame and cargo container carried thereby when the latch frame and container are turned.

A further object is to prevent tipping of an asymmetrically loaded cargo container suspended by hoist ropes from a traveling trolley car.

These and other objects and advantages of the invention are accomplished by a gantry crane construction adapted for use in connection with the ships for carrying containerized cargo and having spaced rails on opposite sides thereof parallel to the ships longitudinal centerline on which the gantry legs can travel. The crane includes a bridge-type transverse main girder supported by the gantry legs above the deck of the ship, at least one hinged outboard cantilever movable between a folded position adjacent a gantry leg where it is capable of being latched at its outer end to the deck structure, and an extended horizontal outboard position in end-to-end alignment with the main girder. Rails or ways for the trolley car rollers are provided on both the girder and cantilever. The trolley car supports a turntable which carries hoist equipment including rope falls which carry a latch frame attachable to a cargo container.

As another aspect of the invention, the rope falls are so connected between the latch frame and the turntable structure that twisting of the latch frame relative to the turntable is greatly restricted, and asymmetrical loading of the containers can be accommodated. This is accomplished by an arrangement wherein the turntable serves to spread the hoist ropes outwardly from their point of connection to the rope drums and wherein the hoist ropes connected at each suspension point on the latch frame are reeved so as to have nonparallel passes between the turntable and latch frame, thus providing a triangulation type suspension wherein tension forces are nonparallel to one another in the lengths of rope terminating at the same point of load application.

Other objects, uses and advantages of the invention will be apparent from the following detailed description and drawings wherein like parts are indicated by like numerals.

Brief description of the drawings FIGURE 1 is an elevational view of a folding jib type single girder shipboard gantry crane embodying the invention wherein the left hand folding cantilever is shown in its extended horizontal position over a dock in solid lines and in its folded position indash lines and wherein the right hand folding cantilever is shown in its folded position in solid lines and its extended horizontal position in dash lines;

FIGURE 2 is a partial plan view of the gantry crane of FIGURE 1;

FIGURE 3 is a fragmentary sectional view on an enlarged scale taken on the line 3-3 of FIGURE 2;

FIGURE 4 is an end elevational view of the gantry crane of FIGURE 1 with a container shown with its axis aligned perpendicular to the centerline of the ship in solid lines and with its axis aligned parallel to the centerline of the ship in dash lines;

FIGURE 5 is an end elevational view on an enlarged scale showing the traveling car and hoist mechanism located on the main girder of the gantry crane as shown in dash lines in FIGURE 1;

FIGURE 6 is a fragmentary front elevational view of the traveling car on the single main girder as in FIG- URE 5;

FIGURE 7 is a fragmentary plan view showing the traveling car as in FIGURES 5 and 6;

FIGURE 8 is a cross sectional view taken on the line 88 of FIGURE 5;

FIGURE 9 is a cross sectional view taken on the line 99 of FIGURE 5;

FIGURE 10 is a cross sectional view on an enlarged scale taken on the line 10-10 of FIGURE 1;

FIGURE 11 is a fragmentary cross sectional view on an enlarged scale showing the traveling gear and drive mechanism for the side running trolley car; and

FIGURE 12 is a fragmentary rear elevational view of the traveling gear and drive mechanism of the trolley car drawn to the same scale as FIGURE 11.

Description of the preferred embodiment Referring more particularly to the drawings and initially to FIGURES l, 2 and 3, there is shown a gantry crane A embodying the invention and located for travel on spaced rails extending longitudinally along opposite sides of a ships deck. The crane A serves to transfer cargo containers B and the like between the cargo hold of the ship C and a dock or barge during loading and unloading when the ship is in port, the crane being of sufficient size to span the cargo hatches D through which the cargo containers B may be lowered into the hold.

General construction The gantry crane A generally comprises spaced gantry legs E which ride along the deck of the ship C on traveling carriages or trucks to be described below. A single main girder F extends transversely of the ship between the legs E to span the cargo hatches D and folding outboard cantilevers or jibs G are located on opposite sides of the main girder F to extend the reach of the crane A over a dock when the ship is in port. The outboard cantilevers G are each movable independently between a downwardly extending folded position adjacent a gantry leg E and a horizontally extended position in end-to-end alignment with the main girder F. As viewed in FIGURE 1 the left hand outboard cantilever G is shown in its extended position in solid lines and in its folded position in dash lines whereas the right hand jib G is shown in its folded position in solid lines and in its extended position in dash lines. The main girder F and cantilevers G are of plate and torsion box construction according to current practice. A side running trolley car H runs along the span defined by the girder F and extended cantilevers G in a manner to be described below.

The gantry legs E are also of plate and torsion box construction and have a generally L-shaped configuration as best seen in FIGURE 4, with the base 10 supported on spaced wheel carriages or trucks 11 and 12. Each carriage 11 and 12 has two wheels 13 which ride on rails 14 secured to the ships deck structure. In addition each carriage 11 and 12 on the starboard leg (FIG- URE 4) has a pair of opposed horizontal rollers 15 spaced on opposite sides of the rails 14 and adapted to engage side rails 16. These horizontal rollers 15 are adapted to carry lateral loads. Connected to the base 10 of each gantry leg E between the trucks 11 and 12 is a drive unit 17 which is pendulously supported from the base by a parallelogram type support in the manner described in US. patent application Serial No. 572,052. Each drive unit 17 has a vertical propeller shaft with a drive sprocket 19 at its lower end, the sprocket being adapted to engage a fixed roller chain or pin rack 20 attached to the outside of each rail support 14. This arrangement serves to propel the crane A along the rails 14 to a desired operating or storage position.

Outboard cantilevers As indicated above the crane A is provided with two outboard cantilevers G located on opposite sides of the single main girder F, which are folded down when the ship is underway and which are connected to the main girder F by means of a horizontal hinge pin at the bottom edge of the abutting ends. When the cantilevers G are extended as shown in sold lines in FIGURE 1 with respect to the left hand cantilever they are secured to the main girder F by means of a horizontal latching mechanism 26 (FIGURE 10). The latching mechanism 26 includes latch plates 27 extending rearwardly from each of the outboard cantilevers G, each plate 27 having openings cut therein to receive latch bolts 28 located in a bolt housing within the main girder F and operated by opposed pistons 29 in hydraulic cylinder 30. Normally the bolts are retracted until the adjacent cantilever G is moved to its extended horizontal position with the latch plates 27 aligned with the bolts, and then the pistons are forced outwardly to move the bolts through the holes in the latch plates 27 and lock the cantilever G securely in position.

Each cantilever G is moved between its folded position and its extended position by means of a hydraulic cylinder 31 pivotally connected at one end to a mount 32 located on the adjacent leg E of the gantry crane A. The piston rod 33 extending from the cylinder 31 is pivotally connected at its outer end to the lower portion of the outboard cantilever G. It will be seen that in the folded position the cantilevers G are each secured to the adjacent gantry leg E by means of a latch plate 34 located near the bottom of each cantilever. A suitable manual or hydraulic latching means such as a means similar to the latch mechanism 25 may be used to secure the plates 34- to the adjacent leg E.

In order to help secure the crane during roll in heavy seas, the ship is provided with a securing station for the crane A. At this station each side of the ships deck is provided with two upwardly extending latch plates or pedestals 37 which receive the corresponding outboard cantilever G therebetween whereby holes in the latch plates 37 and in the plate structure of the cantilever may be aligned and a bolt passed therethrough to latch the crane securely to the deck structure. In this position a rigid triangulation is provided whereby loads experienced by the crane while at sea are transmitted to the ship. This relieves stresses on the rails 14 which might otherwise cause damage either to the rails or to the trucks 11 and 12 and wheels 13 of the crane.

Side-running trolley The side-running trolley H consists of a rigid frame 40 which supports the trolley drive mechanism and which travels on an inclined rail 41 located on top of the main girder F and a secondary rail 42 located at the bottom edge of the main girder F. In like manner the trolley H travels on corresponding inclined rails 43 and secondary rails 44 on the cantilevers G, the

rails

43 and 44 being aligned with the

rails

41 and 42 respectively when the cantilevers are in their extended positions. The angle of the

inclined rails

41 and 43 is such that forces due to th weight of the trolley and the load carried thereby are transferred normal to the bearing face of the rail to minimize any tendency of the trolley to slip off of the rail.

The trolley moves along the

inclined rails

41 and 43 on two inclined rollers 45 and along the

secondary rails

42 and 44 on two side-running rollers 46, each of the rollers 46 being located on one of two downwardly extending legs 47 of the rigid frame 40. The inclined rails 41 and 43 are mounted on a sloping platform 49 welded to the edge of the girder F and cantilevers G.

As a secondary precaution the trolley is provided with lateral guide rollers 48 which engage the side edges of the

inclined rails

41 and 43 best shown in FIGURES l1 and 12. These rollers 48 serve to keep the inclined rollers 45 properly positioned on the

rails

41 and 43 and also take up any axial loads which may occur.

The trolley H is driven along the girder F and cantilevers G by means of a pinion 50 which engages a fixed gear rack 51 secured to a vertical mounting strip 52 welded to the top of the girder F and cantilevers G. The roller chain or pin rack 51 extends the entire length of both the main girder F and cantilevers G as best shown in FIGURE 1. The sprocket 50 is driven through a gear reduction unit 53 mounted on the rigid frame 40, and the drive is supplied by an electric motor 54 as best seen in FIGURE 12. An electromagnetic hydraulic brake unit 56 is interposed between the motor 54 and gear reduction unit 53 to provide braking for the drive when desired and to provide a positive lock which holds the trolley at a desired position and prevents it from rolling uncontrolled along the rails under varying conditions of lateral trim.

An operators cab 59 is mounted on the fixed frame 40 on the left hand side of the trolley H as viewed in FIGURES 1, 2 and 6, the cab being so designed and located as to give the operator optimum visibility throughout the loading and unloading cycles of the crane A.

A turntable 60 is supported by outwardly extending arms 61 of the rigid frame 40 on ball bearing units '62 (FIGURE 3) the ball bearing units including a fixed slewing ring 63 bolted to the arms 61 and a rotating bearing ring 64 bolted to the bottom of turntable 60. The slewing ring 63 has external gear teeth 65 formed therein which are engaged by a pinion 66 mounted on a vertical shaft 67. The shaft 67 is driven by the turntable motor 68 through a gear reduction unitl 69 (FIG- URE 2).

In the illustrated embodiment the turntable 60 can be rotated at least a total of 220 or 110 in either direction from the centerline of the frame 40 of the trolley H. The mid position of the turntable '60 is illustrated in FIGURES 5, 6 and 7, wherein the cargo container B being carried is located with its longitudinal centerline aligned with the longitudinal centerline of the ship. FIG- URES 2 and 4 show the turntable 60 in solid lines rotated 90 counter clockwise as viewed from above, wherein the longitudinal centerline of a cargo container B being carried is parallel to the main girder F. Overtravel is prevented by mechanical stops. The turntable 60 carries the hoist mechanism that includes two rope drums 70 driven simultaneously through a transmission unit 71 by an electric motor 72.

Each drum 70 winds two hoist ropes 73 wound in opposite directions so that each pair of ropes 73 moves simultaneously during turning of the drums. The ropes 73 extend downwardly through a hollow cylinder 74 having vertical reinforcing ribs 75 welded therein, to a lower frame 76 that serves as a support for eight pulleys, two

pulleys

77 and 78, for each rope 84.

The ropes 73 are reeved through the

pulleys

77 and 78 as shown in FIGURES 5 and 6 so as to spread them radially outward from alignment with their point of vertical suspension from the rope drums 70.

A latch frame or spreader 80 is suspended by the ropes 73 in such a manner that the swinging of the load and latch frame 80 and the container B being carried is reduced to a practical minimum. While a latch frame or spreader 80 for a 20' x 8' type container is shown and described, 40 containers may also be used with the equipment provided a larger latch frame is substituted.

The ropes 73 are connected to the latch frame or spreader 80 by means of pulleys 81 mounted in forks 82 which are pivotally connected to the frame 80 by pivot pins 83. With this arrangement the pulleys 81 are aligned with their axes perpendicular to their correspond ing rope fall during the entire vertical range of travel of the latch frame 80. The latch frame or spreader 80 is of conventional design and construction, and forms no part of the invention. Various types of standard latch frames may be used depending, of course, on the size and type of container being transported. The frames may be quickly changed by removing the pins 83.

The ropes 73 pass through the pulleys 81 and then extent diagonally back up to the lower frame 76 as best shown in FIGURE 6. With this arrangement the container can be turned by the turntable with a minimum of twisting of the container and latch frame about vertical axis and relative to each other even though the container B is supported well below the lower frame 76.

Operation During the loading of cargo containers B from a dock to the cargo hold of ship or to a location on deck, the crane A is operated as follows:

Assuming the operation begins with the crane secured at the forward limits of its travel on the rails 14 and not raised on jacks, the ends of the cantilevers G are first disconnected from the latch plates 37 on the ships deck and the outer ends of both outboard cantilevers G are disconnected from the adjacent gantry leg E. The hydraulic cylinders 31 are then operated to raise the cantilevers G to the extended horizontal position in end-toend alignment with the single main girder F. Finally the latch mechanisms 26 are operated to lock the cantilevers in operating position relative to the main girder F with the

inclined rails

41 and 43 and the

secondary rails

42 and 44 aligned respectively with one another. The crane can now be moved longitudinally along the deck of the ship on the-rails 14 until it is opposite the containers to be loaded.

In the meantime the trolley H will have been unlocked from its secured seagoing position and the latch frame 80 released from storage. The crane operator then operates the drive motor 54 to move the trolley H along the main girder F and out onto the cantilever G to a position over a cargo container B to be loaded. While the trolley H is moving, the turntable 60 will have been rotated if necessary a sufiicient amount to position the latch frame 80 in proper alignment with the container B.

When the trolley stops, the hoist motor 72 is operated to turn the rope drums 70 in a direction to lower the latch frame 80 onto the container B. After latching is complete the motor 72 is operated in the reverse direction to raise the latch frame 80 and container B up to the container carrying position shown in FIGURES 4 and 5.

When the latch frame 80 is raised to a position about feet below its upper limit or traversing position, the turntable motor 68 may be operated if necessary to position the container B with its longitudinal axis aligned parallel with the main girder F to assure proper clearance between the container B and the gantry legs. This is not necessary however in the case of x 8 containers (FIGURE 4). The trolley H is then moved along the cantilever G and main girder F while carrying the container B at a sufiicient height to clear obstructions on deck such as barges or other containers. When the trolley completes its travel across the main girder F, the crane A may be propelled along the rails 14 if necessary to position the container B over its storage location. At the same time the turntable motor 68 may be operated to turn the container 90 if it is tobe stored longitudinally of the ship. Finally, the hoist drum motor 72 is operated to lower the container B into position after which the latch frame is released and the frame raised again to its highest carrying position.

For unloading the cargo containers the operation is just the reverse with variations to suit the circumstances. After loading or unloading is complete the crane A is moved to the stowage position. The latch mechanisms 26 are then released and the cantilever G lowered using the cylinders 31, to the folded position where they are secured to the adjacent legs E of the crane A in the manner described. The lower end of each centilever G is secured to the corresponding latch plate 37 on the ships deck. In this manner the crane is very securely latched in place while the ship is underway.

The trolley H is also secured midway between the ends of the single main girder F and latched in place utilizing the machanism provided. If desired the crane A may be jacked up to relieve the load on the wheel bearings, and spacers inserted between the rails 14 and the trucks 11 and 12. The spacers are of course removed again while the crane is being made ready for operation.

While the invention has been shown and described with reference to a specific embodiment thereof, this is intended for the purpose of illustration rather than limitation and variations and modifications will become apparent to those skilled in the art within the intended spirit and scope of the invention as herein specifically illustrated and described. Therefore the patent is not to be limited in scope and effect to the preferred from shown herein nor in any other way that is inconsistent with the extent to which progress in the art has been advanced by the invention.

We claim:

1. A gantry crane adapted for travel on spaced parallel rails on the deck of a ship for loading and unloading cargo, comprising a single transverse main girder span ning the cargo hatches of the ship, at least one hinged cantilever pivotally connected to an end of said main girder and movable between a folded position alongside one of the gantry legs and an extended horizontal outboard position aligned end-to-end with said main girder, a trolley car adapted for travel laterally of said ship along said main girder and said extended cantilever, said trolley car being supported at the side of said main girder and said cantilever to bear against said main girder and said centilever along lines of force which apply a torsional load thereto, a turntable mounted for rotary movement on said trolley car and hoist mechanism carried by said turntable, at a height essentially above the lowermost surface of said main girder.

2. A gantry crane as defined in claim 1 wherein said turntable includes an upper platform which rests on said trolley, a lower frame spaced below said trolley car, a central support connecting said lower frame to said upper platform, inner pulleys centrally located on said lower frame and adapted to receive hoist ropes of said hoist mechanism from said upper platform, outer pulleys mounted at the outer perimeter of said lower frame and adapted to receive said hoist ropes from said inner pulleys and a latch frame suspended below said lower frame by said hoist ropes.

3. Apparatus as defined in claim 2 wherein said latch frame is provided with perimetrically spaced pulleys, each of which receives one of said hoist ropes, said pulleys having supporting forks pivotally connected to said latch frame for movement about an axis perpendicular to the axis of their respective pulley and wherein each hoist rope is reeved through one of said latch frame pulleys and extends back upward to a connection point on said lower frame to define a triangle formed by its outer pulley on said lower frame, its pivotally mounted pulley on said latch frame and said connection point.

4. Apparatus as defined in claim 3 wherein said forks of said latch frame pulleys are connected to said latch frame by removable pivot pins.

9 10 5. A gantry crane as defined in claim 1 in combination References Cited with a container ship having two latching mechanisms on UNITED STATES PATENTS the deck structure thereof, one on each side of said ship outwardly of the adjacent rail, said gantry crane including 1,670,733 5/1928 Moor? 212*18 XR two of said hinged cantilevers pivotally connected to the 5 3,042,227 7/1962 Tantlmger 214.45 3,051,321 8/1962 Ramsden 212-14 opposite ends of said main girder and means on said cantilevers and said respective gantry legs for latching said cantilevers when in their folded position to said gantry legs, and latching mechanisms on the outer ends GERALD FORLENZA Pnmary Exammer of said cantilevers, co-operable with said latching mech- 10 FRANK E. WERNER, Assistant Examiner anisms on said deck structure to provide a rigid triangulation for securing said crane to said deck structure at a US. Cl. X.R.

latching position on said ship. 212-15 3,254,775 6/1966 Bevard et a1.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 3 ,467, 263 Dated September 16 1969 Raimunds-Auzins et a1. Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 5 and 6, assignors to Morgan Engineering Company, Alliance, Ohio, a corporation of Ohio" should read assignors to United Industrial Syndicate, Inc. doing business as Morgan Engineering Company, Alliance, Ohio, a corporation of New York Signed and sealed this 1st day of June 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR.

WILLIAM E. SCH Y ER, JR. Attestlng Officer Commissioner 0% l atents FORM PO-1050 (10-69) USCOMM-DC B0376-F'69 u.s. GOVERNIIIIIT nmmus ornct l9" o-su-su