The gantry is a bridge-type crane in which the horizontal bridge is set on two outriggers to form a gantry shape. This kind of crane runs on ground rails and is mainly used for handling and installation in open storage yards, shipyards, power stations, ports, and railway freight stations.
Gantry crane structure:
The hoisting mechanism, trolley running mechanism, and bridge structure of the gantry crane are basically the same as those of the bridge crane. Due to the large span, the crane operating mechanism mostly adopts a separate driving method to prevent the crane from running skewed and increasing the resistance, or even causing an accident. The lifting trolley of the gantry crane runs on the bridge, and some lifting trolleys are jib cranes. The outriggers on both sides of the bridge frame are generally rigid outriggers; when the span exceeds 30 meters, one side is usually a rigid outrigger, while the other side is connected by ball ammonium and a bridge frame, which makes the gantry a statically indeterminate system. , This can avoid the additional stress caused by the lateral thrust under the action of the external load, and can also compensate for the longitudinal temperature deformation of the bridge. The wind area of the gantry crane is large. Crane rail clamps interlocked with running gear. The bridge frame can be without a cantilever at both ends; it can also be cantilevered at one end or cantilevered at both ends to expand the working range. The semi-gantry crane bridge has outriggers at one end and no outriggers at the other end and runs directly on the high platform.
Gantry cranes are divided into 4 types.
This kind of crane is the most widely used and can handle various pieces and bulk materials, with a lifting capacity of fewer than 100 tons and a span of 4 to 35 meters. Ordinary gantry cranes with grabs work at a higher level.
Hydropower station gantry crane
It is mainly used for lifting and opening and closing gates, and also for installation operations. The lifting capacity is 80-500 tons, the span is small, 8-16 meters; the lifting speed is low, 1-5 meters per minute. Although this kind of crane is not often hoisted, once it is used, the work is very heavy, so the work level should be appropriately improved.
It is used to assemble the hull on the slipway, and there are always two lifting trolleys: one has two main hooks, which run on the track of the upper flange of the bridge; the other has the main hook and an auxiliary hook, which are on the lower flange of the bridge. Runs on rails for flipping and hoisting large hull sections. The lifting weight is generally 100~1500 tons; the span is 185 meters; the lifting speed is 2~15 m/min, and the fretting speed is 0.1~0.5 m/min.
for container terminals. After the trailer truck transports the containers unloaded from the ship by the quay wall container carrying bridge to the yard or the rear, the container gantry crane stacks it or directly loads it away, which can speed up the turnover of the container carrying bridge or other cranes. The yard that can stack containers with a height of 3 to 4 layers and a width of 6 rows is generally used in the tire type, but also in the rail type. Compared with the container straddle, the container gantry crane has a larger span and height on both sides of the gantry. In order to meet the transportation needs of the port terminal, this kind of crane has a higher working level. The lifting speed is 8-10 m/min; the span is determined according to the number of container rows that need to be spanned, and the maximum is about 60 meters, corresponding to the lifting weight of 20-foot, 30-foot, and 40-foot long containers about 20 tons and 25 tons, respectively. and 30 tons.
A bridge-type crane was developed by increasing the span of a gantry crane, also known as a loading and unloading bridge. It is used in open storage yards, ports, railway freight stations, etc. The structure of the common carrier bridge is similar to that of the large gantry crane. feature is:
- The handling objects are mainly bulk materials in large quantities;
- The span is large, generally more than 30 meters, and some up to 170 meters;
- The operation is frequent and the productivity is high, generally 500~1500 tons/hour, the working speed is high, the lifting speed is 60~70 m/min, the running speed of the trolley is 100~350 m/min, and the working level is high;
- The operating mechanism of the carrier bridge is only used to adjust the working position and is a non-working mechanism. When the span is large, the bridge frame of the carrier bridge is supported by a rigid outrigger and a flexible outrigger. The bridge frame and the two outriggers can be connected by bolts; the connection with the flexible outriggers can also be through ball ammonium or column ammonium so that the flexible outriggers can have a certain range of deflection relative to the bridge frame. The bridge frame is composed of the frame beam, and the lifting trolley runs on the track of its upper chord or lower chord. Some trolleys have a slewing boom, which is equivalent to a boom-type running on a bridge.