A new brand is not always born from scratch. Sometimes it appears as a result of an agreement between producing countries, and then is separated. Very often, she retains the traits inherent in both parents. A vivid example of such a solution is the Soviet-German production of construction cranes, founded in the 70s of the last century .
For use on the territory of the Union, versions of the RDK-250 were produced. Technical characteristics, pros and cons, as well as the history of the creation of this "real monster" among our brothers, we will consider in this review.
Model history
Before moving on to the history of the described crane, it is worth noting one interesting fact. It was created by the Germans for use on the territory of the Union. But the prototype of the German model was the MKG-25 crane, created in the Ukrainian SSR. Its name was deciphered simply - a crane with a lifting capacity of 25 tons, on multi-wheeled tracked carts. The first German crawler crane came out of the Zemag Zeitz gate in 1967.
This was the first model of the RDK series - RDK-25. The crane was reliable, unpretentious in maintenance, and most importantly, it could work on almost any site. The machine was powered either from its own power station or from an external 380 V generator. In practice, it was the Soviet model - the Germans changed the crane's movement system, putting several instead of one motor, each of which was responsible for certain actions.
Development stages
In 1972, the first model was discontinued. It is replaced by an improved version of the RDK-250. The capacity of the new crane remains at the same level, but the “0” in the name should indicate that this is a fundamentally new development.
In fairness, it should be noted that only the power plant became new, the remaining blocks migrated from the first modification. The customers accepted the crane, noting, however, that it does not pass according to the standards of railway transportation adopted in the Union. For transportation, it is necessary to remove not only the boom, but also the cab, otherwise the height of the load goes beyond the limits. The Germans mark this option with the index “1” (first) and process the crane operator’s cabin. So the RDK-250-2 model appears - this time the changes concern only the height of the driver’s cab.
Lifting capacity in numbers
It should be noted that cooperation with the Germans continued until the collapse of the Union. In 1983, RDK-400 crawler cranes appeared. As the name implies, the model's carrying capacity was 40 tons. This crane was produced for 7 years, and in 1990 a machine entered the market, which already reached 63 tons. The entire line of Germans was marked the same way: first the name of the model, then 2 digits - carrying capacity, and a constant "0" at the end - improved. At the same time, not only versions for the Union were noted, but also for the CMEA countries. In parallel with 250, the RDK-280 crane came out. From the name it is clear that he had a different carrying capacity, other motors (production of Czechoslovakia), and a calculation for other climatic conditions.
Modifications
About 15 thousand cranes with a lifting capacity of 25 tons were produced for the Soviet Union. In addition to the already mentioned versions 1 and 2, the Germans also released two more modifications. To work in the Far North, the RDK-250-4 version was intended. It differed from all previous models with an insulated cabin, the ability to work at -50 degrees, enhanced protection, and other details.
In addition to it, a crane was issued, which received the additional index “3” in the name. He could boast of a more powerful and modern diesel engine, as well as some new developments. One of them was an improved power scheme, which had the ability to completely switch to a single source. If electricity suddenly disappeared at the construction site, the crane switched to work from a diesel generator. The latter consisted of two parts, which made it possible to disconnect them separately, without prejudice to work.
Features of German developments
Unlike the Soviet prototype, German-made cranes could be used not only in the construction of buildings and structures. In the presence of a grab, the machine could be successfully used for loading and unloading. Thanks to a certain unification, the German-made jib crane could use most of the additional nozzles used for conventional machines of this class.
The division of the load into several motors could change the mobility of the crane. In addition to the main tasks, new developments could be used to move heavy loads.
Boom gear
Even after the development of the RDK-250-2 version, when traveling long distances from the crane, it was necessary to dismantle the boom. But this need also got a flip side - workers on the site could lengthen the boom.
In the basic version, it had a length of 12 meters. But with the help of additional inserts, which, like the arrow itself, were attached to the finger joints, it could be increased almost threefold. The maximum length could be 35.5 m. In addition, the Germans provided for two versions of the jib - fixed rigid 5 m long or movable-rotary. The latter could be elongated.
Optional equipment
The possibility of lengthening made it possible to use this jib crane not only for its intended purpose - for lifting and moving the load. According to the specifications of the developer, the basic equipment could be of two types - boom or tower, the main differences between which were in the upper end. But later, in addition to these two options, a third appeared - a piling mast, mounted on the cab, like ordinary tower equipment. This immediately expanded the use of the crane - from the initial stages to the end of construction. And the ability to lift cargo to a height of more than 20 meters allows you to use it for the construction of structures of sufficient height.
Crane transportation
The same specifications claim that RDK is a self-propelled crane, however, like most construction equipment, its own speed of movement is only 1.5 km / h. For the limits of the construction site, this can be called a good indicator, especially when you consider that he could move with the load on a hook, but when transporting it to a new place of work, it was necessary to use either road or rail transport.
The movement was carried out in several stages:
- dismantle of an arrow, tower, mast;
- driving on a low loader trawl (case of road transport);
- shipping.
Next was the reassembly at a new location.
For transportation by rail, he most often with the help of another crane, was transported and placed on an open platform.
Currently
The Germans finished the production of cranes in 1993. Nevertheless, at many high-rise buildings in Russia, you can still see it. Thanks to reliability, unpretentiousness, the ability to move with the load, the model is now in operation. It should also be noted that spare parts RDK-250 can be found in any large specialized workshop.
You can replace metal inserts for the boom, rope, wheels or caterpillar assemblies, other crane parts. Despite the end of production, the choice of components allows you to use this version for a very long time.
Separately, you can mention the possibility of unification, thanks to which, the crane can use almost any device developed for other models. As well as the ability to use attachments, turning it into a pile driver for driving piles or even a drilling rig.
Characteristics
In this section, we will include other parameters of the RDK-250 that remained before this in the shade. Technical characteristics are presented in the form of several lists. Let's start with the external parameters (all in millimeters):
- width - 3225;
- length - 6275;
- height - 3350.
All data are indicated without boom, in transported position.
Cargo characteristics for standard work on an arrow with inserts:
- lifting height (maximum) - 45 m;
- lowering depth - 6 m;
- carrying capacity - 25 t;
- maximum and minimum reach - 22 and 4 m, respectively;
- cargo lifting speed - 7.5 m / min,
- lowering - 15.5 (it should be noted that two motors could work on lowering).
- movement speed with cargo on the hook - 1 km / h, without cargo - 1.5 km / h.
Here we also attribute that the self-propelled crane had separate mechanisms of movement and rotation, as a result of which the upper part with the cab was able to make a complete revolution around the axis in two minutes.
It should also be noted that the caterpillar base allowed to carry out work even on an inclined plane:
- in boom version - 3 degrees at load and up to 15 without;
- in the tower version - 2 degrees with the length thereof up to 27 meters, from above - no more than one.
Since the rotary part of the crane almost completely repeats this on pneumatic wheels, we will dwell in more detail on the undercarriage, the lower part. The movement of the crane is carried out using a pair of engines, on the shafts of which the drive wheels of the tracked carts are located. Between the upper, rotary and lower parts laid current collectors connecting all electrical circuits. An output cable with a plug sleeve is provided for powering from an external power source. In addition to the crane operator, another person can sit in the cab. In the front of the lower frame is a fenced trolley for repairing engines of the movement mechanism. Access to the rest of the engines and maintenance of the power supply system is through the covers on the bottom.
Conclusion
The RDK-250 crane, created as a result of Soviet-German cooperation, became a real find for mass construction in the early to mid-1970s. The presence and possibility of using additional equipment more than paid for the cost and size of such a machine. Moreover, the crane could not be bought. Many large construction companies agreed with their own TO provide it for rent.