Equipment

The segment of Caterpillar excavators is the most capacious on the russian market of building and road equipment. The competition here is very tough: each of the players interrupting one another demonstrates the advantages of its equipment. To be always "on horse", companies-producers must do untiring work on improvement of its equipment.

 

For past two years constructors and technologists of the Group GAS were actively concerned with the excavator subject and because of this there appeared immediately several new and modernized models of excavators.

 The new model of caterpillar excavator ÅÒ-26i developed by designers of the Group GAS, is intended for loading and unloading of crushed rocky breeds, metal breakage, lumber, and also for other works in processing and lumber-making branches. On it there're installed a new jib and handle, providing the greater height and radius of unloading. In the advanced hydrosystem, shorter hoses and hydrocontours are used. On ÅÒ-26i the rising system of the cabin of parallelogram type which provides for the operator the best review of the working space at greater heights of unloading. The design of the excavator provides the usage of bucket grab and log-capture. Besides, the equipment is adapted for work with a magnetic plate. The improved ergonomics of the cabin provide more comfortable operating conditions of the operator.

 On the model ÅÒ-26FS, which has replaced the excavator ÝÎ-4225À-07, there installed a modernized heel of the jib which now is executed under the kinematic scheme of base models of the excavators ÅÒ-26 and ÅÒ-30, and a heel of the handle for maintenance of transport dimensions. The model is improved by the system of the automatic centralized greasing. The design of the working equipment grants an opportunity of installation and use of other kinds of working bodies, such as ladles of direct digging and ladles for loading the loose and loosened materials with a folding jaw. On the excavator ÅÒ-26FS as well as on the ÅÒ-18LC, the unified cabin with panoramic glazing is istalled, altogether with an adjustable steering column, joystick management of the working bodies, which considerably facilitates the work of the operator.

 The excavator ÅÒ-18LC has a lower specific pressure upon the ground – only 0,31-0,35 kg/sm2 due to the increase in width of the tracj from 600 up to 900 mm. It provides the new model a reliable work on the grounds with a weak bearing surface. On an excavator can be installed both the Minsk engine by capacity 105 h.p., as well as the Perkins engine by capacity 123 h.p. The machine design provides an opportunity of work with a greater set of the replaceable working equipment: various ladles, bucket grabs, hydroground, and rippers.

   The Unification with a wheel excavator allowed to create an essentially new machine. The Model ÅÒ-20 of the Group GAS is more efficient, and is equipped with the modern hydroequipment. The given novelty is considerably more comfortable for the operator due to the application of the new ergonomic cabin.

 One more innovation in the segment of excavators – the bonnet system, as in a car. The engine and the pump are before eyes at the opening of the back cowl, the hydroallocator is under the lateral cowl and is accessible for service.

 The similar system was used by the Joint-Stock Company " Exmash" in the models E180Rlc and E150Clc. On the excavators are installed pressure boost engine Deutz with liquid cooling. The engine incorporates to the pump unit by means of Centaflex clutches. The system of hydrodrive, executed under the scheme LUDV of Bosch Rexroth company, provides unlimited quantity of combinations in the running cycle, high accuracy of operating, minimal losses of capacity. For acceleration of the running cycle the distribution of the stream of the basic LS-pump between executive mechanisms occurs to a priority of the rotary mechanism. On hydrocylinders of the jib, handle and rise of the cabin, installed brake valves of series A-VBC of the Italian manufacture with functions of the hydrolock (lock-up of the cavities of the hydrocylinders and exclusion of «flash» of elements of the working equipment and the cabin), the "antishock" valve (maintenance of smooth lowering of the working equipment and the cabin, exclusion of the dispersal under action of the body weight, exclusion of a break of the stream in hydraulic highways), « the emergency valve » (exclusion of falling of the working equipment and the cabin in case of a break of the hose of high pressure) and the valve of restriction of the carrying capacity.

   The extension of the running gear and decrease of the width in comparison with the standard model is applied by Hitachi Company for the two novelties - ZX180LCN-3 and ZX400LCH-3( at transportation the excavator ZX180LCN-3 with the low-frame trailer corresponds to the automobile dimension of transportation). The top supporting skating rinks and arms of these carrier rollers are increased in sizes for the rise of durability of the construction. For the maintenance of a greater reliability and rigidity the links of the crawler had been strengthened, and their form was changed. The horizontal beam is strengthened thanks to the improved design and the increased racks of the closed section. The Durability of the section has increased up to 35 %. The top arm of the boom is strengthened with usage of a high-strength steel. At the hinge at the junction of the ladle the top part of the handle is hardened by means of thermal spatter WC ((Wolfram Carbide) for the increase of durability at contact of its surface to the ladle owing to decrease in twitching. Persistent plates from the reinforced pitch are intended to decrease the noise and to increase the durability. For the advance of solidity the basis of the jib has been increased. This improvement raises durability and reliability at carrying out of heavy works.

 The letter «H» in designation of the excavator ZX400LCH-3 testifies that it is intended for digging works on heavy ground and hard rocks. The machines of the H version possess the protection of the crawlers, securing the parts and the bottom skating rinks from damage and deformation. Moreover, the protection does not let the ingress of stones into the crawlers, thus preventing an overload of the running part that, in turn, reduces deterioration and probability of breakage. The work of the jib is advanced: at performance of combined operation of lowering of the jib and the handle, the speed of the handle can be increased approximately by 15 %.

 Company JCB on their excavators has applied a new system of clearing the hydraulic liquid Plexus with the degree of clearing up to 1,5 micron. It allows decreasing the time of carrying out the procedural service on replacement of the hydraulic liquid up to 5000 machine-hours (instead of the traditional 2000 machine-hours). Besides, on all the novelties – models JS290LC, JS330ME and JS360LC – engines Isuzu, since 2008 made on the ecological standard Tier 3, and also powerful hydraulics Kawasaki are installed. These engines were specially designed for application on full-revolving excavators in view of the operational working features of these machines.

     The design of the jib is changed – now it is all-welded(the bottom and top shelfs of the jib are executed from a one-piece plate), it considerably increases its rigidity and, accordingly, the working parameters and a resource of the machine though it raises the cost price of the machine's manufacturing. The given construction of the jib allows applying the ladles of a greater volume. In the hinges of connection the jib-base and the jib-handle are installed the plugs from an alloy of bronze with graphite inclusions, which noticeably enlarges the time of their exploitation.

The introduced control system AMS (Auto) on the JCB excavators allows carrying out the more effectively difficult excavations demanding high productivity. It automatically switches operating modes of the excavators between limiting capacity and profitability, depending on the load upon the hydraulic system for maintenance of the maximal productivity, fuel profitability and the efficient management at work, continuously transfers specifications to the screen, mounted in the cabin. Switching of the modes can be carried out manually, as well as in the Auto mode which excludes mistakes of the operator. The special function briefly allows increasing pressure in the hydraulic system by 10 % for the gain of detachment effort on the ladle and handle. The electrosystem of the new models – is a dust-washdown, all the electric connections are executed with improved requirements for moisture protection and protection against corrosion – « sea execution ». Storage batteries (2 pieces) correspond to the Heavy Duty standard.

 Two new versions Liebherr Company developed. The Classic Version is useful for classical digging works while the Advanced version represents high-efficiency multipurpose machines which can be used for performance of various works, for example, at extraction of minerals, at works on slopes, in the industry or at the pulling-down of buildings and constructions. For the first time all the updated models of the new sixth generation R 906 Litronic, R 916 Litronic and R 926 Litronic were all presented in April at Intermat ’ 2009 exhibition. Each of the three new models is equipped with a 4-cylinder engine Liebherr. The control of the engine with system integration through trunk CAN-Bus provides the optimum charge of fuel and a more effective utilization of the capacity due to reduction of the frequency range of rotation. The excavators of the new generation are equipped with a high-efficiency and energy-efficient 2-planimetric hydrosystem Positive Control specially developed for technics, which carrying out a plenty of operations for a short term. The smaller running cycle on all the models is achieved not only by the new hydrosystem, but also by the improvement of the drive of the revolving platform of an excavator that has allowed increasing the engine torque by 50 %, and the speed of turn – more than by 24 %. The new running carriages are equipped with advanced drive with greater capacity at movement due to what the productivity also increases. In comparison with the previous models the maximal speed of moving is increased by 17 % – up to 6,2 km/h, and traction effort – by 12 %. The new excavators also externally differ from the predecessors. Now smooth from all the sides the counterbalance is integrated into the back part of the machine, and a box for tools, built in the ladder behind the driver's cabin, is a successful decision from the point of view of practicality. The comfort of the operator became better thanks to a modern ergonomic workplace and the convenient in use interface of the working display. The display output of commands to the color display with the touch panel with function of video and optional monitor of the back-camera considerably facilitates the work.

   LiuGong Company has emphasized on introduction of electronic systems. The model CLG 925LÑ is equipped with a system of automatic capacity control of the engine, the monitoring system of workload on the working equipment, hydraulics and the engine, and also the diagnostic monitoring system over all the equipment of the excavator. In the excavator CLG 225Ñ the control system of the engine has undergone changes, the elements of the running part and the working equipment are strengthened all up. In all the models of excavators in hydrosystem of the working equipment a flowing unloading of pumps is used, which increases smoothness of switching on of hydraulic engines (hydromotors and hydrocylinders), eliminates rise of pressure in the hydrosystem during switching on of the sleeve valves. The Running parts of the frame of the H-shaped form is strengthened by continuous plates, and side beams of the frame represent a welded metallic construction of box-shaped section, increasing its rigidity and durability. The designs of the jib, the handle and the ladle due to thick-plate high-strength steel also are improved, the section of the finger of fifth jib is increased.

   By Volvo company in its new development has been made an emphasis on excavators performing works on clearing of reservoirs, deepening of bottom, and also on formation of slopes of coasts and alignment of the ground. The distinctive feature of such machines – is a long jib and handle, and also the extended running part providing a higher stability that is a necessary condition at performance of such works. The novelties ÅÑ210B LR, ÅÑ240B LR, ÅÑ290B LR are equipped with diesel engine Volvo with the system of direct injection of fuel, a turbosupercharger and an intermediate cooler of air, guaranteeing fuel profitability, low noise level and long service life. The hydraulic system with autoregulation of the workload with convenient operational characteristics is designed so that it reacts on the slightest signals of management of the operator. The excavators are equipped by a reliable electrosystem and a powerful generator. Capacity of the ladle has a range from 520 up to 570 l, which allows machines to carry out various kinds of works. On the excavators of this series cabins Care Cab are built in, which is characterized by a high safety degree, the top comfort and excellent visibility. Ergonomically placed levers of management make the operating of the machine easier, therefore the operator gets tired less. The noise level in the cabin Care Cab is considerably lower, the hydroamortized fixing support reduces the level of vibration, and powerful filters make air pure and fresh.

   The emphasis on the new hydraulic system, and also on the new control systems was made by company New Holland in the models of the series of B. The Control system H.A.O.A. constantly optimizes the capacity of hydraulic system according to the needs of the operator and operating work, providing the best controllability of a machine, productivity, comfort for the operator and economy of fuel. System D.O.C. includes the new advanced hydroallocator which has a second sleeve valve for management of handle work of the jib. The design of the jib and handle has been remade and advanced by means of methodology FEM (methodology of final elements) for the increase of durability only in those zones which are exposed to loadings. Altogether, the new mechanism of hinge suspension brackets of the ladle with double loose leaves has been applied – the durable internal loose leaf "handle/ladle" now has additional protection against deterioration in the place of contact to the mechanism of hinge suspension brackets of the ladle owing to the new additional external bushes executed of wear-resistant steel. On the new models of series B the more powerful engines with system of injection Common Rail, adequating to the newest technologies and developed for the increase of productivity with simultaneous decrease in consumption of fuel and the level of the environmental contamination are established. The company has also paid attention the ergonomics of the excavators. The solid design of the cabin in combination with the viscous shock-absorbers with a silicone fller promotes decrease in vibrations to a minimum. The interior of the cabin has been completely remade: all the switches and controls now are located on the right, according to the requirements of ergonomics.

   The new system CAPO was established by Hyundai Company on its novelty presented in two executions (with a direct shovel – R800LC-7A FS, and a return one – R800LC-7A). ÑÀÐÎ includes the monitoring system of turns of the engine, a monitoring system of hydrosystem, function of a jib's priority, automatic system of heating, system of prevention of an overheat, the monitoring system of transport speed, function of prevention of the engine's restart, a system of self-diagnostics. The engine Cummins QSX is advanced by a double top camshaft (DOHC). The quantity of details is reduced by third, and rings, pistons and the bearings working in a hard mode are made of the strengthened alloyed alloys and high-quality materials. The system of prevention of an overheat is activate automatically reducing the frequency of rotations of the engine up to the bottom border when the temperature of the cooling liquid reaches 110 OS. When the temperature of the cooling liquid is below 30 OS, there activates an automatic system of heating, quickly warming up the motor at rotations of the engine 1150 rev/min. The system of rotation decrease of the engine (up to 1150 rev/min) is actuated, when the machine remains in a neutral position within 4 seconds. Independent diagnostics is prosecuted due to controller CPU by means of which problems in the CAPO-system are found out, caused by failure of electric and hydraulic details. CPU it is capable to identify 48 various types of mistakes which deduces on the LCD-monitor through codes of mistakes. Besides the company does not forget about ergonomics of the models. The cabin of series Robex-7A is initially developed with a low noise level. The microcomputer capacity control system ESS (management of the hydropump capacity according to the number of engine rotations) provides a steady economic work of the excavators of company XCMG under various conditions. Several years ago the excavator factory was allocated in an independent company Xuzhou Xuwa Excavator Machinery Co., Ltd. which also is located in the city of Xuzhou (PRC). On the new models XE200, XE210, XE230, XE250 the highly effective powerful import engine Isuzu of rather small volume corresponding the standard of Euro 2 is installed. The automatic system of prestarting heating ensures the functioning of the engine at low temperatures. The technology with usage of two pumps in hydrosystem provides stability of work of the multirunning distributive valve and greater speed of the stream, which positively influences the overall performance of the jib and the ladle. The strengthened ladle with plates and teeth of a wearproof steel has the flat basis for simplification of works on alignment of surface.

 The emphasis on ergonomics in the new cabin with a climate-control and the monitor with an opportunity of adjustment up to 10 various hinged instruments in the model 312D L was made by company Caterpillar. The Engine Acert which is installed on the novelty, corresponds to the norms of EU Stage IIIA. Pressure is increased in the main hydraulic contour with 299 up to 305 Bar. In the models 329DL (Long) and 336DL (Long) any constructive changes are not present, the designation changed from 325 to 329 and from 330 to 336 for more exact reflection of weight of the machine (29 ò and 36 ò accordingly).

   A number of innovations were introduced on the excavators by the company Komatsu. One of the novelties – PC2000-8 – is completed by an engine with useful capacity of 713 kw, more economic, with the lowered noise level and a design convenient for service. The excavator PC360 is equipped with a greater ladle, has a greater exploitative weight, width of boots. Introduction of the system Hydra Mind allows carrying out operation of two pumps, providing an effective utilization of the engine's capacity. Such system also reduces hydraulic losses during the work of the excavator. The increased pressure head effort of the handle and the effort of cutting of the ladle occurs due to the improvement of the mechanism of the hydrocylinder's hinge plate of the handle.

   The design of the excavator provides an easy access to the points of service. For simplification of clearing in the middle of the radiator by means of a nozzle of a purge by compressed air there widened distance between the radiator and the oil cooler. Thanks to the increase of the base and the track of the crawling drive in the model PC130-7 the side stability and carrying capacity of the excavator are improved. Depending on the conditions of exploitation there's a choice of operating modes, such as active, economic, etc. For maintenance of the raised effort of digging and easier moving the left and right parts of the platform were thickened.

 

 

 Endnote

 

1 – the capacity of the digging/loading ladle, ì3

2 – the maximal height of unloading, m

3 – the weight of a model with width of the crawler 600 mm/width of the crawler 800 mm

4 – capacity of the engine, h.p.

5 – the maximal capacity of the ladle, ì3

6 – capacity of the engine at 1800 rev/min, h.p.

7 – productivity depends on the capacity of the ladle

8 – model with a return shovel

9 – data on model with a direct/return shovel

10 – data for versions Advanced/Classic

11 - SR (short radius) - models with the truncated top platform

12 – productivity, h/min.