Tower cranes have long been the hallmark of construction sites. The construction of residential apartment buildings, business centers, shopping and entertainment complexes cannot be done without them. They belong to highly specialized equipment that provides vertical and horizontal transportation of various cargoes. The KB 408 tower crane lifts loads weighing up to 10 tons to a height of up to 72.7 m. They are widely used in the construction of 16 and 24-story buildings. KB-408 is classified as a mobile, full-rotation crane on rails. This means that it is equipped with a rotating tower, and also moves around the construction site on special crane rails. It is transported between objects only in disassembled form on suitable cargo equipment.
Purpose of a tower crane
Rail cranes are designed for mechanization of construction and installation work in housing and civil construction. They are especially widely used in the construction of multi-storey residential complexes and the development of new microdistricts. Compared to stationary cranes, rail cranes have greater mobility, but require the laying of special crane tracks. There are also wheeled and tracked models, but they are inferior to rail models in terms of carrying capacity and compactness, so they are used to solve special problems (for example, on a difficult construction site). Rail cranes have long held a place of honor at city construction sites.
KB-408 is most widely used in the construction of 16-story high-rise buildings. Also, this crane installation can move bulky technical equipment, be used as a manipulator, and is also very effective in search and rescue operations when clearing rubble.
The KB 408 crane is actively used in construction
In the basic version, the crane has a seismic resistance of up to 6 points; in special versions it can withstand earthquakes of up to 7–9 points. Thus, it can be used in areas with medium to high seismic activity.
Design features of special equipment
The running frame of the KB-408 tower installation is traditional for this series of special equipment. The design is equipped with rotary weather vanes and a portal, the design of which was borrowed from the previous model of this series - the KB-160 crane installation.
The equipment of the tower is unified with elements of similar truck cranes from the KB model range. The designers made significant changes to the design of the KB-408 turret head. The difference from previous models is the size of the pulley ropes and the total number of inventory sections (depending on the modification - from 2 to 6 pieces).
It is also worth noting that the head section of the KB-408 turret can be disassembled, which greatly simplifies the transportation of special equipment to the construction site.
The KB-408 control cabin is designed specifically for a high crane, which requires its placement at a height of more than 20 m. The installation methods of this structural element are traditional for installations of this line. The improved cabin of the KB-408 tower crane differs from the base model by the following advantages:
- ergonomic design;
- modern security system;
- wide view;
- innovative heating panels;
- air conditioner.
The main boom of the KB is of a sectional type, made of high-strength metal pipes, the arrangement of which creates a lattice structure, the sections of which are securely connected by flange fasteners. A cargo cart is attached to the boom, the movement of which is controlled by tilt.
The hook cage of the tower crane is made in the form of a biaxial suspension. The structure consists of a pair of cheeks and axles on which cross-beams, hooks and blocks are mounted. The structure is equipped with casings to protect the hook cage blocks.
Device
KB-408 belongs to the full-rotating tower cranes of the 4th size category and is equipped with a rotating tower, as well as a girder boom with a load trolley. The main part of the load falls on the platform, which consists of an all-welded frame and three beams with trusses. Here, at the base of the tower, is the lower counterweight, which consists of ten massive reinforced concrete blocks. The crane tower has a modular design, the boom is sectional. The crane is also equipped with a safety module with a coordinate protection system. The cabin is equipped with a heating, ventilation and air conditioning system.
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KB-408 is recognized as one of the most reliable and safe cranes. The security module includes:
- touch graphic interface, convenient and easy to use;
- control system self-diagnosis module;
- function of remote diagnostics via GPRS channel (installed at the request of the customer).
Other advantages of the model:
- Fully variable speed control with squirrel cage motors;
- high levels of strength and safety;
- long service life of mechanisms;
- improved performance and controllability;
- comfortable crane cabin.
The main components of the KB-408 are interchangeable with other cranes of the 4th size group, which increases the availability of spare parts and reduces the likelihood of downtime.
Swivel mechanism
The rotating platform KB-408 is located at the base of the structure. The rotating mechanism looks like a roller circle with a diameter of 2500 mm. Also installed on the platform are winches, blocks and electrical equipment for the cargo trolley. This distinguishes the KB-408 from its predecessor KB-160.
Shooting and cargo winches are located at the top of the platform. Fixed with brackets. There is also a portal at the top. 10 reinforced concrete blocks are attached to the rear of the platform as a counterweight. The counterweight protects the structure from swinging of the rotating mechanism when carrying loads. A support hinge and working struts are also installed on the platform.
Rotary platform KB 408
Running frame
As with other cranes with a slewing tower, the KB-408 running frame is attached directly to the slewing bearing, which receives and transfers the load from the slewing part. It is an all-welded frame with rotating weather vane beams. Weather vanes provide fixation of cargo trolleys. Using a switch, the weather vanes are transferred to transport and working condition. 4 cargo trolleys are installed on the frame, two of which are electrically driven.
Portal
The portal is located at the top of the turntable and is a quadrangular structural element, open on both sides. This is one of the key design elements on which productivity and safety largely depend. The purpose of the portal is to ensure stability of the boom position; it also allows you to increase the height. In addition, the portal prevents the tower from falling during crane installation due to four locking elements.
The structure is based on two trihedrons connected by box beams. The portal is secured by a truss element and cylindrical struts.
Be sure to read: Technical characteristics of KS 45721
Tower sections
The crane tower has a modular design and consists of 2–5 sections. Their exact number depends on the design of the crane. Structurally, the tower consists of a head, a section and struts. The head is a metal lattice with racks, ladders and platforms that provide rigidity to the structure and ease of work for operators and maintenance personnel. The head section of the tower is collapsible, which distinguishes the model from similar ones.
Cabin
The machinists who worked at KB-408 note comfortable working conditions. The cabin provides good visibility, effective heat and noise insulation, and is equipped with ventilation and heating panels. At the customer's request, air conditioning is installed. In addition, the cabin is treated with an anti-corrosion compound, which ensures safety, increases service life, and also improves appearance.
The developers specially worked on the ergonomics of the cabin: the controls are conveniently located, and indicators and displays provide effective control of the location and load of the working parts. The standard modification KB-408 is equipped with a cabin for low cranes, which can rise to a height of up to 20 m. The “high-rise” modification 408.21 is equipped with cabins for high cranes (over 20 m), providing better visibility and more comfortable working conditions.
Crane cabin KB 408
Hook clip
The hook clip or suspension provides gripping, lifting and moving of the load. Structurally, it is a biaxial suspension, consisting of two cheeks and two axes, on which blocks, traverses and a hook are installed using ball bearings. The blocks are additionally protected by metal casings.
Jib
KB-408 is equipped with beam construction booms. Compared to a lifting boom, a beam boom has a larger mass, is more difficult to transport and operate, but requires less drive power. The beam boom ensures rotation of the cargo trolley, which, in turn, moving along the boom, changes its reach.
The standard boom length on KB-408 is 35 m. Modification 408.21 can be supplied with a boom length of 45 and 50 meters.
For production, metal pipes welded into a lattice are used. Compared to booms welded from angles, pipe booms have better lightness and strength, and also effectively reduce wind loads on the crane due to their good streamlining. These technical characteristics determined the wide use of this type of design.
The boom design is sectional. The sections are connected to each other using flange connections. The boom has two working positions: horizontal and inclined.
Be sure to read: Technical characteristics of the DEK-251 crawler crane
How to manage
The beam design allows the load to be guided more smoothly to the installation site.
The tower crane is controlled using special software and hardware located in the cabin, in particular, command controllers and radio-controlled remote controls.
Switching between landing and ascent speeds occurs via a single switch.
This crane is distinguished by thirteen versions; only the boom radius values differ (20, 30, 35), respectively, the lifting capacity and the lifting and lowering values.
The beam boom is installed at an angle, for example, 43 degrees and 30 degrees.
The crane has:
- self-diagnosis system of control mechanisms,
- remote control via GPRS,
- control using touch elements,
- frequency control of motors.
A cabin air conditioning system is also available as an option.
Crane equipment additions:
- Heating in the cabin. The crane can operate successfully both at +40℃ and -40℃. Since it is intended for zone IV. Accordingly, it has a well-heated operator's cabin.
- Load sensor . The load lifting mechanism is equipped with a load control sensor, thanks to which the main components of the system are monitored.
- Control of the movement of cargo elements . Thanks to a special device (frequency), the movement of concrete slabs and other loads occurs smoothly and without interference.
- Cabin temperature control. Thanks to modern electronic components in the cabin, temperature is regulated.
- Safety system in case of rope break (shock absorber, tie). Works and holds the boom when the rope breaks.
We offer for your information an article about the technical characteristics of the MKG-40 crane, as well as about the control features of this model. At the following address: https://spez-tech.com/tehnika/stroitelnaya/kranyi/avtomobilnie/ivanovets/harakteristiki-ks-45717-1.html, you will learn how the Ivanovets KS-45717-1 works.
And here we will look at another crawler crane - MKG-25.
Specifications
Dimensions:
- rear clearance – 4.35 m;
- base – 6 m;
- track – 6.0 m.
Other characteristics:
- Weight – 95.2 tons. Travel speed – 18.0 m/min.
- Load capacity – up to 10 tons, with maximum boom reach – 6 tons.
- Load moment – 160 (kNm) tm.
- Boom radius – 6–30 m, with maximum load capacity – 16.0 m.
- Electric motor power is 123.6 kW.
- Crane rotation speed – 0.65 rpm.
- Load lifting speed – up to 67 m/min.
- The speed of smooth loading of the load is 4.8 m/min.
- Lowering depth – up to 5 m.
Lifting height:
- with a horizontal boom – up to 46.6 m/min;
- with an inclined boom – up to 57.8 m/min.
Cargo trolley speed:
- with a horizontal boom – up to 7 m/min;
- with an inclined boom – up to 30.0 m/min.
Cost of new and used equipment
In Russia, you can buy a new KB-408 crane for at least 7–10 million rubles. from the manufacturer Nyazepetrovsk Crane Manufacturing Plant. A beam boom 40-50 m long can also be supplied with the crane.
At the buyer’s request, the selling company can equip the cabin with a modern air conditioning system, which undoubtedly plays in favor of this model of equipment.
Equipment from 2005 can be found at a cost of 4.5 million rubles. Newer forklifts will cost more. It is also widely practiced to rent tower cranes from 800 rubles. at one o'clock.
Thus, the KB-408 model among its brothers is in the forefront in terms of technical equipment and load capacity. It has a relatively inexpensive price on the market and has many positive reviews among contractors. If the choice is about high-quality lifting equipment, then it’s definitely worth taking a closer look at the KB-408 tower crane.
Modifications
The manufacturer offers 15 design options for the KB-408.21 tower crane (an index from 00 to 14 is added to the name). The most popular version is KB-408.21-02.
Photo source: giraffecrane.ru
Among the technical characteristics that vary depending on the modification of the crane is the lifting capacity at maximum reach (it can be 3, 3.5 or 5 tons). The maximum load moment is, accordingly, limited to 160, 180 or 200 tm. But here it is worth saying that for 3-ton versions the maximum reach reaches 40 m, and for 5-ton versions - 30 m. But upon additional order, it is possible to install booms with a length of 45 and 50 m. We also note that the maximum weight, which in all cases is 10 t, allowed at an outreach of 16, 18 or 20 m.
Let's look in more detail at the characteristics of the KB-408.21-02 tower crane.
About technology
KB - 408 - tower crane. The base is a rail platform. The maximum lifting capacity of all modifications of the crane is up to 10 tons, the lifting height depends on the modification and is shown in the table. The main area of use is the construction of civil residential and industrial buildings and structures.
The crane is equipped with a load trolley, which is suitable for transporting building elements in horizontal and vertical planes.
- Low cost
- High maintainability
- Simplicity of design
- The crane is mounted using its own mechanisms
Since KB is a 408 tap of the fourth size group, it has identical components with taps of this group. Which greatly simplifies its repair.
The crane tower is designed to be modular. The number of modules from 2 to 5 depends on the modification.
Control system
The control system has a hardware complex and a software part; the control system is located in the cabin. In addition, the crane has remote controls for radio control. The speed of landing and ascent is controlled using a single switch.
The crane is equipped with the following systems:
- Registration, performance analysis and self-diagnosis system
- Remote control system via GPRS
- Frequency control of motors, which allow you to control the speeds of turning, lifting, and moving loads.
- Load sensors signal dangerous operating modes of the crane
