Malfunctions and repairs
Repair of refrigerated semi-trailers is carried out in service centers. The chassis of new trailers are in good condition and trailer repairs will not be needed for a long time. Parts such as brake discs, pads, and rubber fasteners are subject to natural wear and tear. Repair or replacement of such parts is carried out by specialists from service centers. If necessary, specialists perform diagnostics of the refrigeration unit, replace components and parts, refill with refrigerant, check and identify faults.
American low loader semi-trailers - heavy trucks
Heavy-duty semi-trailers are designed for transporting road and construction equipment. Important parameters of heavy trucks are maximum load capacity, platform length and width, maximum approach angle, loading height. Low loading height (the height of the transported equipment in the transport position above the road level) allows you to transport high loads under bridges, overhead contact lines and in tunnels. This necessitates the use of small wheels or a "hinged frame" where the load being transported is placed between the jib and the rear trolley below the level of the trolley. For equipment with large dimensions in height, semi-trailers with a loading height of about 600 mm are used. It is worth noting that all patents and modern design developments traditionally belong to American design bureaus. Particular attention is paid to structural strength and welding of components. To tow super-heavy trailers, special American tractors with 3 rear axles are used. To hold the semi-trailer in a horizontal position, as well as for ease of coupling and uncoupling with a truck tractor, support devices are installed in the front part of the frame. They can be mechanical, one or two speed, or hydraulic using a hand pump or hydraulic station. Taking into account the constant tightening of traffic police requirements for compliance with the established dimensions, vehicle and axle loads, such equipment quite often ensures compliance with the regulated parameters. Well-known manufacturers - Witzco Challenger, Trailboss, Trail-King, Fontaine, Load King, Cozad, Aspen, Talbert, Rogers, Fruehauf.
Low bed semi-trailer for 50, 60 tons
Low bed semi-trailer for 50, 60 tons
Three axles, total length - 14.6 m, length of the level platform - 6.7 m, top point of the level platform - 0.63 m, ground clearance - 0.23 m, width - 2.43 - 2.58 m, 12 extensions of 30 cm on each side, total width with extensions - 3.03-3.18 m, 22.5 wheels, reinforced spring suspension, hydraulic line, air brakes. Important parameters of heavy trucks are the dimensions of the platform. The overall width in Russia is limited to 2.5 m. As a rule, the semi-trailer is equipped with 30 cm extensions, and the working platform can be expanded up to 3.2 m, and it becomes possible to transport reinforced concrete slabs and heavy tracked equipment, such as a Komatsu 355A bulldozer.
Low bed semi-trailer 35 tons
Low bed semi-trailer 35 tons
Total length – 14.1 m, length of a flat platform – 6.7 m, top point of a flat platform – 0.63 m, ground clearance – 0.23 m, width 2.43-2.58 m, on each side there are 12 extensions of 30 cm, total width with extensions – 3.18 m , 22.5 wheels, spring suspension, hydraulic line.
Semi-trailer for transporting cutters and rollers weighing 35 tons
For milling machines, asphalt pavers and rollers, ramps with an entry angle of 9 degrees are required, and for tracked vehicles this angle can reach up to 18 degrees. Small entry angles are ensured by the use of long folding double ramps. To lift such heavy ladders, hydraulics are used, which requires hydraulics of the tractor or the use of hydraulics on the semi-trailer itself. Mechanical ladders have entry angles of 9-18 degrees. The movement of two-section ladders from the transport position to the working position is carried out by the corresponding kinematic links, and hydraulic cylinders serve as the power drive.
Semi-trailer for transporting cutters and rollers weighing 35 tons
Total length - 16.1 m, length of the level platform - 10.05 m, height of the top point of the level platform - 0.86 m, ground clearance - 0.55 m, two parking supports, 8 mounting rings on each side, folding hydraulic ladders 0.91 m X 3.3 m with approach angle 9 degrees, axle load - 10.22 tons on each axle, leaf spring suspension, air brakes with ABS, 17.5 wheels, load capacity - 35 tons, two front supports, additionally - it is possible to install 10 extensions on each side.
20 ton semi-trailer with mechanical ladders
20 ton semi-trailer with mechanical ladders
The trailer is equipped with folding ramps located at the rear, along which small-sized construction or municipal equipment can drive onto the loading platform under its own power. For transportation of Caterpillar D7, D8 bulldozers, length – 10.5 m, length of flat area – 6.85 m, width 2.58 m, covering – wood, ramp dimensions – 0.60 m x 1.54 m, spring suspension, axle load – 10 t per axle, 17.5 rims, 3 mounting rings on each side, one front support, air brakes with ABS.
Types and brands of semi-trailers
To transport various goods, manufacturers and transport companies often use a type of vehicle such as a semi-trailer. This type of equipment differs from a conventional trailer in that the front part of its body is attached to the fifth wheel of the tractor, thereby moving part of the weight of the load onto the tractor. This design allows you to increase the weight of the cargo and reduce the number of flights. The following technical characteristics are important for a semi-trailer: its weight, load capacity, number of axles, length of the cargo area and the materials from which it is made.
Semi-trailers are used in various areas of cargo transportation. There are different types of semi-trailers for each type of cargo.
— Flatbed semi-trailers do not have a roof and are used to deliver construction materials that are unpretentious in terms of weather conditions (bricks, boards, fittings, pipes, etc.). It is convenient because its load capacity reaches 29 tons, and it is also equipped with folding sides, which makes loading/unloading from the sides and top easier.
— Tilt semi-trailers are the most common (60% of all semi-trailers used in Russia). They transport equipment, pallets, and furniture. The awning protects the cargo from the effects of weather conditions. Also, this type of semi-trailer can additionally be equipped with a removable frame and a sliding roof.
— Curtain semi-trailers are a type of tilt semi-trailers. A distinctive feature of such semi-trailers is a steel frame and a retractable awning. It is also equipped with a fully or partially removable roof. Such characteristics allow you to load the semi-trailer from any convenient side. This type of transport is suitable for transporting large indivisible cargo.
— Isothermal semi-trailers and refrigerated semi-trailers. This type of transport is designed for transporting goods that require a certain temperature regime. Isothermal semi-trailers, due to their technical characteristics, are designed for transporting fruits, vegetables, chilled meat, fish, that is, for those products that do not require freezing. Walls made of special isothermal materials are able to maintain the temperature at the required level, but the temperature cannot be increased or decreased. Refrigerated trucks are equipped with refrigeration equipment and are designed for transporting frozen food and flowers. Both semi-trailers are capable of maintaining the desired temperature inside the body, provided the outside temperature is from -30 to +30 degrees.
— Container semi-trailers are designed for storage and handling, transportation, loading/unloading of containers. They are equipped with a low frame and pneumatic retractable platforms. Low-bed semi-trailers, depending on technical characteristics, transport one or two twenty-foot containers or one forty-foot container. The load capacity can reach 34 tons. There are also container semi-trailers with a standard frame, their load capacity is up to 31 tons.
— Semi-trailers-car carriers transport passenger cars (double-deck) and trucks (single-deck) vehicles. To insure against minor damage, they are equipped with sides, an awning, but can also be open. Load capacity - up to 25 tons. Car transporters are capable of moving up to 8 cars at a time.
— Heavy-duty semi-trailers (otherwise called trawls) are designed for transporting heavy, large equipment. Most often they are equipped with three or four axles, some of which (to reduce the load) are rotary.
— Tipper semi-trailers are popular in agriculture. They can withstand weights of up to 40 tons, and various types of unloading are also possible (one-, two- and three-way).
Modern semi-trailers can be divided into two types: American and European. Each type has its own distinctive technical characteristics. American semi-trailers are equipped with two (less often three) axles with double tires. Brakes - drum. While driving, all bridges are operational and are not liftable. European semi-trailers are most often equipped with three, very rarely four axles with single tires. Brakes - disc. Some bridges may be subject to traffic. The European version also has a tray for storing spare tires, which is rare in the American versions. Different types of awning semi-trailers differ in the method and design of the awning, and some isothermal and refrigerated semi-trailers in the American version become low-bed, which increases their volume.
Semi-trailers can be used in many areas of activity. With the invention of new materials and the improvement of technology, the model ranges of this type of trailer transport are constantly being replenished.
GREAT DANE INTRODUCES SUPER SEAL XLT REFRIGERATOR
In cooperation with its suppliers, the famous American trailer manufacturer Great Dane presented its fundamentally new model of a lightweight refrigerator. Volvo, Thermo King, Meritor Wabco and Hendrickson International took part in the creation of the model. The development was exhibited at the annual Mid America Trucking Show in Louisville, Kentucky.
The refrigerator is designed and built on the basis of the well-proven SuperSeal series, which for five years has been the lightest version of the refrigerator in the version for use with truck tractors. The model is called SuperSeal XLT and demonstrates the excellent result of collaboration between design offices developing components for tractor-trailers and trailers. “SuperSeal XLT is easy to operate and easy to maintain,” says Keith Hammond, president of Great Dane.
The main novelty is the use of new, never before used ultra-light materials. The refrigerator's skin is made of thin panels manufactured using technology from SAES Getters of Colorado Springs. The panels are so thin that they can not only increase the internal cubic capacity of the trailer, but can also be successfully used in any climatic conditions, with any temperature changes.
The insulation material is soldered into the panel and is a combination of vacuum and polyurethane microporous foam applied in a grid pattern. The new material is called Getter and has the highest gas-absorbing properties. The getter has half the thermal conductivity of conventional sandwich panels and is able to “maintain” the set temperature inside the trailer for a long time even when the refrigeration unit is turned off.
The design of the trailer presented at the exhibition is completely borrowed from the design of the famous SuperSeal model. However, the XLT body is made entirely of Getter panels. The thickness of the panels on the walls is only 1.5-2.0 cm, and on the ceiling 2.2 cm. The front end wall has a thickness of 6 cm, and even then, only in order to carefully secure the refrigeration system compressor. The joints between the walls and the ceiling are additionally processed by Getter. “As a result, we are introducing a super-light and insulated trailer with even more usable volume,” Creat Dane announces.
In addition to its impressive insulation properties, SuperSeal XLT has a large number of electronic sensors that allow the driver to monitor the condition of the cargo inside the trailer directly from the cab. Thanks to the joint development of Thermo King, Volvo, Great Dane, Meritor and Hendrickson, the driver can adjust the trailer suspension, control the temperature in various parts of the refrigerator and control the fuel level in the independent refrigeration system right from his workplace. The same information is transmitted using the RL protocol to the control panel at the carrier’s central office. The driver is spared the need for daily reports. The GPS Global Positioning System tracks the location of the trailer around the clock.
“SuperSeal XLT is the product of a combined effort to research and improve production technologies. XLS is a system that integrates the trailer and tow vehicle into one unit for the overall benefit of the business,” says Charlie Fetz, vice president of Great Dane. The electronic information system helps the driver to control not only numerous parameters, but also to use the refrigerator in a wide variety of conditions. The digital communication system and on-board computer system comply with the SAE 1-1587 standard and operate in the PLC4 Trucks protocol, i.e. Now information enters the cockpit not through wires and cables, but through digitally encoded signals.
According to the rules of Federal legislation, since March 2001, information about the condition of the brake pads must be displayed on the driver's display. On the XLT Great Dane showpiece, there is Meritor's TCSII Easy-Stop ABS system. The system provides the driver with information about the condition of the suspension and braking system, and in the event of a malfunction, it works as a hazard warning lamp.
The XLS is equipped with a new development from Thermo King - an SB-200 information system unit called i-box. The block indicates possible malfunctions in the thermostat, refrigerant leaks, temperature surges in the cargo compartment, and reports the condition of the fuel in the refrigeration system. The i-box is an option and can be installed in any Thermo King service station if desired.
The demo trailer featured Meritor's new braking system and microprocessor-based tire pressure monitoring system. The system is able to inform the driver about the condition of the brake discs and the degree of wear of the pads. Interestingly, the same system works as an automatic suspension stabilizer when the road surface angle changes. “SuperSeal XLT is an example of how cutting-edge technology and advanced development can be brought together and presented on a system like XLS,” emphasizes Keith Hammon.
After researching the potential market and having a sufficient number of orders, XLS will be put into mass production.
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