Having been in any port city, paying attention directly to the port, you can always see the so-called port crane on the horizon. Without these hoisting machines, it is simply unrealistic to imagine not only sea or river “gates”, but also the construction site of hydraulic structures, shipbuilding enterprises. We will talk about these units in more detail in the article.
Marking
Immediately, we note that the expression “port crane” is not completely correct, since cranes of a wide variety of systems and types can be used in the port. The correct phrase will be “portal crane”, the name of which comes from its built-in structural element - the portal.
Port gantry cranes have the following designations:
- The letter "K" means "crane."
- "P" is a portal.
- D / M / P - dock, mounting, reloading.
- K / G - hook, clamshell (these letters refer to the old notation).
The meaning of the numerical indices is as follows:
- 1 - indicator of maximum load capacity on the main hook or at maximum reach.
- 2 - maximum outreach.
- 3 - the gauge of the portal.
In cases where the carrying capacity will be different depending on the departure, the designation of the departure itself and the carrying capacity indicator occurs in two digits - through a fraction.
Job responsibilities
Now consider the port cranes depending on their purpose:
- Reloading. This is the most widespread type of port cranes. Its carrying capacity ranges from 5 to 30 tons. A grab (for bulk materials), a magnetic washer for overloading scrap metal or a hook suspension for piece goods can be used on it as a load-gripping body.
- Mounting is most often used in shipbuilding and ship repair plants, in ports. Its body is almost exactly the same as that of the reloading "brother", and the difference is only in the presence of a jib on the trunk. Also characterized by a low speed of movement of the hook. There can be two traction winches (for the main and auxiliary lifting). The carrying capacity ranges from 12.5-60 tons.
- Stapelny - this is perhaps the smallest type of portal units. In fact, it is an assembly machine, which found its application only in enterprises engaged in the construction of various ships. A characteristic feature of the crane is a high portal and a trolley type current lead. It is capable of holding a load that is close to its maximum load capacity in weight for a very long period of time (installation of a ship’s hull takes more than one day). The carrying capacity is 30-160 tons.
- Dock's. This port crane, due to its specifics, has a very small payload. Of the design features, it is worth highlighting a narrow portal and the presence of anti-theft captures (in addition to tipping over). Also, the mechanism is limited by the degree of excitement of the sea or river.
Basic structural elements
Port cranes in most cases consist of the following main parts:
- Portal. Its main purpose is to reduce the weight of counterweights by increasing the site. Due to this design of the center of gravity, the probability of the capsizing of the crane is excluded. In addition, between the legs of the portal is the passage of railway or road transport. It also allows the crane to pass over any structure.
- The foot is the part of the portal, the bottom of which ends with trolleys (drive or idle).
- The heading of the portal. With it, the legs connect. In addition, it perceives the load from the rotary part. In the head mounted electrical equipment of the crane movement mechanism.
- Slewing ring.
- Current lead.
Technical details
Port cranes, the characteristics of which can be different, are generally produced and operate taking into account the following indicators:
- Carrying capacity.
- Departure of an arrow and speed of change of its departure.
- The speed of the crane.
- Turning speed.
- Wheel load indicator.
- Cart speed (if any).
Also, when studying a port crane, special attention should be paid to the mechanism for changing the boom extension, which, in turn, can be hydraulic, rod, tackle or crank type.