CRANES
Both overhead travelling cranes and gantry cranes are types of crane which lift objects by a hoist which is fitted in a trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building while the hoist can be moved to and fro across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
Overhead travelling cranes and gantry cranes are particularly suited to lifting very heavy objects and huge gantry cranes have been used for shipbuilding where the crane straddles the ship allowing massive objects like ships' engines to be lifted and moved over the ship. Two famous gantry cranes built in 1974 and 1969 respectively, are Samson and Goliath, which reside in the largest dry dock in the world in Belfast, Northern Ireland. Each crane has a span of 140 metres and can lift loads of up to 840 tonnes to a height of 70 metres, making a combined lifting capacity of over 1,600 tonnes, one of the largest in the world.
However, gantry cranes are also available running on rubber tyres so that tracks are not needed, and small gantry cranes can be used in workshops, for example for lifting automobile engines out of vehicles. Both overhead travelling cranes and gantry cranes are types of crane which lift objects by a hoist which is fitted in a trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building while the hoist can be moved to and fro across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
Overhead travelling cranes and gantry cranes are particularly suited to lifting very heavy objects and huge gantry cranes have been used for shipbuilding where the crane straddles the ship allowing massive objects like ships' engines to be lifted and moved over the ship. Two famous gantry cranes built in 1974 and 1969 respectively, are Samson and Goliath, which reside in the largest dry dock in the world in Belfast, Northern Ireland. Each crane has a span of 140 metres and can lift loads of up to 840 tonnes to a height of 70 metres, making a combined lifting capacity of over 1,600 tonnes, one of the largest in the world.
However, gantry cranes are also available running on rubber tyres so that tracks are not needed, and small gantry cranes can be used in workshops, for example for lifting automobile engines out of vehicles.
PATENT DERRICK SYSTEMS
HALLEN-DERRICK
The Hallen-derrick employs the twin topping principle , which allows good control of a single derrick . This derrick was originally designed for loads of 5-8 tonnes but there are hallens , which , can lift loads of 100 tonnes . The derrick can be mounted on all types of mast or derrick post and can make a traverse from port to starboard of 1600 _1800
In original design a fixed outrigger was fitted to the mast ,which was commonly known as D frame .This had the effect of keeping the topping lifts at a sufficiently wide angle to one another to ensure the derrick remaining steady even when swung out over the ship's side to an angle of 800 from the fore and aft line .The D frame also helped to kep the derrick stable in all position , even the vessel had a list . However under some operational conditions there were disadvantages when using the D frame :
1.When the derrick was swung outboard , the sharp angle created by the contact of the toppling lift guy pennant with the frame caused excessive strain in the topping lift.
2.There was a tendency for the single wire pennant on the topping lift to slip above or below the frame when working at difficult angles , once again putting excessive strain on the topping lift.
3.The contact with the frame caused chafing on the pennant.This was reduced by fitting rollers to the frame or by protecting wire.
THE LIVERPOOL RIG
Generally these types of rigs are used for light cargo operations such as bags and hides . A single derrick is plumbed over side and secured by means of bull rope of 24 to 32mm size , to a portable bollard clamped to the hatch coaming . When the whip is slack , the bull rope operator heaves on the rope and belays the line (2) So that the blocks are in the hook is lowered and the load lifted and raised. As it clears the coaming the bull rope is slacked and the load is veered across the deck (1) When the load is plumbed under derrick head the bull rope is all slack . This method provides a very quick loading or discharging of cargo with an experienced man manning the bull rope .
RAIL MOUNTED GRANTY CRANE
Rail mounted granty cranes (RMG) are specialized and container handling machines.An RMG travels on rails to lift and stack 20 or 40' containers in the yard area.The container is lifted by a spreader attached to cables.Rail mounted cranes come in a variety of models with different sapms and overhangs.These cranes are specially designed for intensive container stacking due to its automatic and less need for human handling . Compared to the rubber tyred gantry crane (RTG), the RMG has the advantages of being driven by electrical power , cleaner , bigger lifting capacity , and higher gantry travelling speed with cargo . Rail-Mounted Gantry cranes are particularly effective for rail / road transhipments of large quantities of containers.
Both overhead travelling cranes and gantry cranes are types of crane which lift objects by a hoist which is fitted in a trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building while the hoist can be moved to and fro across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
Overhead travelling cranes and gantry cranes are particularly suited to lifting very heavy objects and huge gantry cranes have been used for shipbuilding where the crane straddles the ship allowing massive objects like ships' engines to be lifted and moved over the ship. Two famous gantry cranes built in 1974 and 1969 respectively, are Samson and Goliath, which reside in the largest dry dock in the world in Belfast, Northern Ireland. Each crane has a span of 140 metres and can lift loads of up to 840 tonnes to a height of 70 metres, making a combined lifting capacity of over 1,600 tonnes, one of the largest in the world.
However, gantry cranes are also available running on rubber tyres so that tracks are not needed, and small gantry cranes can be used in workshops, for example for lifting automobile engines out of vehicles. Both overhead travelling cranes and gantry cranes are types of crane which lift objects by a hoist which is fitted in a trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building while the hoist can be moved to and fro across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
Overhead travelling cranes and gantry cranes are particularly suited to lifting very heavy objects and huge gantry cranes have been used for shipbuilding where the crane straddles the ship allowing massive objects like ships' engines to be lifted and moved over the ship. Two famous gantry cranes built in 1974 and 1969 respectively, are Samson and Goliath, which reside in the largest dry dock in the world in Belfast, Northern Ireland. Each crane has a span of 140 metres and can lift loads of up to 840 tonnes to a height of 70 metres, making a combined lifting capacity of over 1,600 tonnes, one of the largest in the world.
However, gantry cranes are also available running on rubber tyres so that tracks are not needed, and small gantry cranes can be used in workshops, for example for lifting automobile engines out of vehicles.
PATENT DERRICK SYSTEMS
HALLEN-DERRICK
The Hallen-derrick employs the twin topping principle , which allows good control of a single derrick . This derrick was originally designed for loads of 5-8 tonnes but there are hallens , which , can lift loads of 100 tonnes . The derrick can be mounted on all types of mast or derrick post and can make a traverse from port to starboard of 1600 _1800
In original design a fixed outrigger was fitted to the mast ,which was commonly known as D frame .This had the effect of keeping the topping lifts at a sufficiently wide angle to one another to ensure the derrick remaining steady even when swung out over the ship's side to an angle of 800 from the fore and aft line .The D frame also helped to kep the derrick stable in all position , even the vessel had a list . However under some operational conditions there were disadvantages when using the D frame :
1.When the derrick was swung outboard , the sharp angle created by the contact of the toppling lift guy pennant with the frame caused excessive strain in the topping lift.
2.There was a tendency for the single wire pennant on the topping lift to slip above or below the frame when working at difficult angles , once again putting excessive strain on the topping lift.
3.The contact with the frame caused chafing on the pennant.This was reduced by fitting rollers to the frame or by protecting wire.
Velle Derrick
The Velle derrick is quite similar to the Hallen but without use of
outriggers. On top of the boom is a T-shaped yoke assembled. Also here, the guys serve for topping and lowering the boom but they
are fastened on the yoke with four short, steel-wire hanger-ropes. The ends of
the topping and lowering ends of the halyard are secured to half-barrels on one
winch. In this way the boom moves in the same speed as the winch veers the
topping end of the halyard and hauls the lowering end of the halyard, and vice
versa. The slewing ends are also wound on to another half-barrel. For hoisting
the cargo, there is a third winch to hoist to cargo on the yoke. Runners
decrease swing and rotation of the cargo. A joystick duplex controller steers
the Velle derrick.
STULCKEN DERRICK
The patent Stulcken derrick is used for very
heavy cargo. It stems from the German shipyard Blohm+Voss GmbH. This derrick can handle up to
300 tonnes. The Stulcken can be made ready in few
minutes, which is a lot faster than a traditional heavy derrick, doesn't
require lots of space and is operated by four winches. Between two v-shaped,
unstayed Samson-posts is the Stulcken secured. This makes it possible to let
the derrick swing through the posts to reach another hatch. For each post is a
hoisting winch, a span winch and a lever that is run by one man only. Bearings,
swivels, sheaves and the gooseneck can be unattended for up to four years and create only a friction of about 2%. The span tackles are
independent and the halyard is endless. With the revolving suspension heads on
the posts it takes ten minutes to swing all the way through. In the
double-pendulum block type, half of the cargo tackle can be anchored to the
base of the boom. In order to double the hook speed, the halyard passes through
the purchases since one end is secured which reduces the SWL to its half. Typical
dimensions of a 275 tonne Stulcken are: 25.5 m length, 0.97 m
diameter, 1.5 m to 3.4 m diameter of posts, 18 m apart the posts
(upper end) and 8.4 m apart the posts (lower end). The hook of a
full-loaded 275 tonne Stulcken can move 2.3 m per minute. If only one
purchase is secured and the derrick is loaded with 137 tonnes the hook
gains velocity to 4.6 m per min. Even more speed can be gained when the
winch ratios are reduced to 100 tonnes (triple speed) and 68 tonnes
(quadruple speed). Detaching the union table the double-pendulum block type of
Stulcken is able to swing through which allows the lower blocks to swing freely
to each side of the boom. In this way the derrick reaches a vertical position.
A bull rope easily pulls the derrick to the other side until the weight of the
cargo tips the derrick over. The span tackles now have the weight on the other
side. The union table is fixed again and the derrick can start its work on the
other side. There are also Stulcken with single-pendulum blocks. At this type
the cargo hook is detached and the lower and upper cargo block are hauled into
the center of the Stulcken. To tip the derrick over the gravity is here used
again. A derrick helps pump oil in most offshore rigs.
THE LIVERPOOL RIG
Generally these types of rigs are used for light cargo operations such as bags and hides . A single derrick is plumbed over side and secured by means of bull rope of 24 to 32mm size , to a portable bollard clamped to the hatch coaming . When the whip is slack , the bull rope operator heaves on the rope and belays the line (2) So that the blocks are in the hook is lowered and the load lifted and raised. As it clears the coaming the bull rope is slacked and the load is veered across the deck (1) When the load is plumbed under derrick head the bull rope is all slack . This method provides a very quick loading or discharging of cargo with an experienced man manning the bull rope .
RAIL MOUNTED GRANTY CRANE
Thanks for sharing about different kinds of cranes have a look at
ReplyDeleteCrane Service
Farana Crane
Crane Hire
Crane Rental