Classification of special excavators
1. material mining class
(1) water and land dual-use excavator
The water and land dual-use excavator, based on the platform of the ordinary excavator, is equipped with a hollow floating box chassis, so that it has the ability to walk, stop and work on the soft ground such as swamps and beaches. This kind of equipment is still dominated by bucket excavating materials, and has strong adaptability in river dredging and lake beach operations.
(2) a long arm excavator
The ordinary excavator becomes the long arm excavator by replacing the lengthened boom and bucket bar. The long arm excavator can achieve a large range of operation, widely used in river dredging, Lake cleaning, reservoir maintenance and other special conditions, but also can be used on large slope repair work. When a long arm excavator is used for underwater excavation, in order to ensure a better vision, a underwater camera is usually arranged on the bucket to enable the driver to grasp the bucket and material state at any time.
The amphibious excavator and the long arm are combined to form a complementary advantage, and can better complete the shoal and underwater excavation work. It is a necessary machine for the operation and maintenance of the large tidal flat.
2. material grabbing class
The excavator is equipped with grab type implements, which has the functions of grasping and grasping materials, and can realize the functions and uses of excavators. This kind of grab has many kinds of actions. Therefore, it is often necessary to add new oil supply and control devices on the basis of the original hydraulic system. There are mainly 4 types of material grab excavators: pipe gripper, wood grab, plum blossom grab and shell bucket.
(1) pipe gripper
Pipeline construction requires not only the equipment to grasp the pipeline, but also the flexibility to control the attitude of the pipeline. Usually, the pipe gripper is driven by a hydraulic motor, which can achieve 360 degrees of rotation, with the excavator's moving arm, the bucket rod, the four connecting rod mechanism, the turning of the car and so on, so as to realize the accurate positioning of the 5 degrees of freedom of the pipe. This kind of excavator is widely used in oil and natural gas, petrochemical, metallurgy, port dredging and other industries such as pipeline laying and pipeline products transshipment.
(2) wood grabbing tongs
The wood gripper, also known as wood gripper and wood clip, is made up of a group of intersecting fork tongs, mainly for grasping wood or straw materials. Usually, the wood grab has 3 movements of pitch, rotation and opening and closing, and can accurately grasp wood or other materials by adjusting posture. The clamp is simple in structure and can replace a lot of manual handling and loading. It is convenient and flexible to use and greatly improves the efficiency of operation.
(3) plum blossom grab
Plum blossom grab is a special tool widely used in iron and steel plants, smelters, ports, wharves and scrap transportation. The plum blossom grab mounted on the excavator is driven by hydraulic cylinder, and the most common flap is 4~6. When working, the grab is usually only opened and closed, so the oil drive of the excavator bucket bucket can be used. Changing the excavator to the grab machine has little change to the excavator and is easy to realize. In order to make the driver get a good view and ensure the safety and efficiency of the operation, the driver's cab is generally designed to be increased.
(4) shell bucket
The shell shell is named after its shape and action resemble the shell. When hopper closes, the hopper can form a closed cavity. The shell bucket consists of main frame, left bucket, right bucket and driving hydraulic cylinder. The shell bucket is similar to the plum blossom grab, and generally only has the opening and closing movements. With large capacity but small digging force, the shell is mainly used for loading and unloading of light and loose materials, such as sand loading and coal loading for ports, wharfs and coal fields.
3. material rupture and shear class
The excavator can not only realize the transportation of earthwork and other materials, but also can be used for crushing, breaking and shearing various materials by installing different genera. There are 3 main types of material breaking excavators: broken hammer, hydraulic shear and soil cleavage device.
(1) broken hammer
Broken hammer, also known as hydraulic crusher, is a kind of special machine with wide application of excavator. It is mainly used in construction, road demolition and mine rock crushing. A large number of excavators are now equipped with hydraulic crushing pipes at the factory.
(2) a split earth device
When the bucket of an ordinary excavator excavates the relative soft materials such as earthwork and gravel, it can easily penetrate the base material to realize the excavation, but when the base is compacted for a long time or as a whole rock, it can not be excavated normally. In such a situation, it is usually broken up by crushing and other methods before mining.
To strengthen and improve the structure parts such as the movable arm and bucket rod of the ordinary excavator, the excavating force is raised to about 2 times of the original, and then the single tooth cracked earth device is fitted to the excavator, and the equipment can effectively break the hard material on the surface. Under special working conditions, the equipment is not only efficient in operation, but also very small in noise (far less than the breaking hammer).
(3) hydraulic shear
The hydraulic shear has similar structure to the pipe grabbing machine. It also has 2 actions of turning and opening. The principle of the work is as follows: the hydraulic cylinder has a huge thrust, which is magnified through the mechanism, and forms a great shear force at the jaw, so as to cut off the ordinary steel, cement and other materials. Hydraulic scissors are mainly used for scrap metal cutting, automobile dismantling, building dismantling, etc. It can be installed on a multi section super long arm excavator to demolish tall buildings, so that another special type of excavator can be produced.
3. material ramming
The vibratory rammer can be installed on the excavator to make it a material compaction type excavator. The vibratory rammer realizes the specific function through the output periodic impact force. The vibration rammer can complete the ramming operation of the plane, the inclined plane and other complex base surface, and use it with the excavator. It can be used not only for the ramming of the abutment back, the culvert side, the corner corner, the embankment and the embankment, but also for the tamping of the auxiliary facilities of various building grooves, foundation pipes and other cities.
4. wood cutting and lumber
(1) deforestation
The adaptability of the excavator is improved, and the cutting function is fitted to it. Modern cutting excavators (logging machines), as a kind of forestry joint operating equipment, can not only cut wood, but also shoot skin, produce raw strips and logs.
(2) collector class
In forest farms, bulldozers or tractors and skidding excavators are often used for towing large timber. The adaptability improvement of the excavator and the addition of the skidding genera to the excavator can be converted into a skidding excavator. As shown in Figure 7. At present, domestic main excavator manufacturers such as Xugong, Liugong, and 31 have developed such products accordingly. In the steep slope, deep trench and other machines can not reach the location of the completion of skidding, need to be excavated by a winch cutter. At present, there are Komatsu PC200-8M0 excavators and Carter 320D excavators that have already achieved this function.
5. material cleaning class
Hydraulic excavators are equipped with hydraulic tape drives, which can be used to clean bushes and low arbors. In addition, this kind of equipment can also be used for the opening of forest fire barrier belts, the daily maintenance of forest roads, and the opening of emergency barrier zones of rivers and emergency fire prevention channels.
Key points of design
Consider whether a special excavator meets the needs of special operation, mainly from 2 aspects, one is to effectively complete the required special task, and the two is to ensure the long-term and reliable work of the excavator under the special operation condition. For simplicity, only the skidding excavator is taken as an example.
The forestry skidding excavator should have 4 functions: first, the timber drag function. To achieve this function is relatively simple, keep the wood at one end on the ground, tie the other end of the wood and hang it in the higher position of the machine to drag and pull. Two is the drag and drop of wood walking function. The key to drag and drop wood walking is to ensure that the chassis system has enough traction to overcome the resistance generated by the whole machine and wood. The three is the function of loading and unloading towed timber, that is, the bundled timber can be connected to and disconnected from the fuselage. The four is unloading the wood stacking function. It will be sent to the lump after the concentration point.
To analyze the above functions, we need to add a wooden frame to the chassis and set up the suspension points at the higher position of the wooden frame. In order to ensure that the excavator can drag and pull wood, designers need to calculate the traction force of the excavator. It is necessary to redesign the bucket to realize the function of loading and unloading of towed timber and the stacking function of unloading timber. By fitting the profiled shovel on the excavator, the operator can adjust the position of the single wood in multiple dimensions and put it in the right place.
The terrain of the forestry is rugged and more and more mountainous, so it is necessary to strengthen the lower frame of the excavator and the four round area, and take some protective measures, such as the use of the whole rail protator, the strengthening guide seat, the improvement of the support sprocket and so on. In order to prevent the exposed pipes from touching the branches and trees, the necessary protection should be made to the corresponding pipelines. The excavators at the cutting ground are at any time facing the threat of falling trees. Out of safety considerations, the excavators should not only take the necessary protective measures for the parts of the excavators, such as the oil tanks, the cab and other parts of the driving room, but also leave the operators with escape windows in the cab.
