Auxiliary Tools for Repairing Large Excavators

Large excavators, whether using wire ropes or hydraulics, are known for their high efficiency and large output, serving as the mainstay of open-pit mining. Adhering to the concept of "bigger is better," commonly used excavators can typically reach scales of 500 to 1,000 tons. While large machines are convenient to use, maintenance can be troublesome. Unlike wheeled vehicles like dump trucks or loaders that can be driven back to the workshop for repairs or even towed if unable to move autonomously, other types of tracked vehicles, whether proficient at moving like bulldozers or not like drills, are relatively easy to transport back to the workshop due to their smaller tonnage. However, large excavators, due to their excessive weight and limited mobility, are challenging to transport back to the workshop, especially when repairs are needed. Transporting them via trailer is not easy and requires the assistance of large cranes, while terrain limitations may prevent trailers from leaving the mine pit. Therefore, large excavators are generally repaired on-site.

Repairing on-site in open-pit conditions poses far greater challenges than in workshops. Lack of overhead cranes and essential tools further complicates repairs. Even with tools like jacks, cranes, and aerial work platforms, repairs remain arduous. In developed countries, repair teams often mobilize all available resources to simplify tasks and enhance efficiency. Methods like using loaders to lift hydraulic cylinders or bulldozers to drag buckets and tracks are employed. Despite these efforts, repair tasks remain labor-intensive and time-consuming.

To enhance repair efficiency and reduce labor intensity, foreign manufacturers have developed various specialized tools. These tools streamline repair tasks, shorten repair durations, and increase equipment uptime. Additionally, using specialized tools mitigates safety risks associated with makeshift methods. Below are descriptions of several such tools.

Hydraulic Jack Tool:

The hydraulic jack is a commonly used tool in excavator maintenance, required for repairing components like the swing bearing and gear ring or when servicing the entire undercarriage. In the past, stabilizing the upper structure of a heavy-duty excavator, weighing hundreds of tons, often involved using wooden blocks, which was time-consuming, labor-intensive, and required materials. Nowadays, specialized hydraulic jacks are indispensable. Typically, these specialized jacks feature 3 to 4 sets of hydraulic columns, each consisting of 1 or 2 hydraulic cylinders, with lifting capacities of up to 1,300 tons. To ensure smooth lifting and prevent damage to pivot shafts and other rotating components, hydraulic columns must remain synchronized.

Structurally, there are two methods: direct support and beam support. Direct support is simpler and more economical, while beam support is more complex but offers better compatibility, flexibility, and stability, capable of withstanding strong winds or other potential safety risks. Regardless of the method, there is an issue with support points. For direct support, the rear support point is easily accessible, but the front end often requires connecting to the boom cylinder bracket (for hydraulic excavators) or the boom bracket (for wire rope excavators) using auxiliary supports, which may necessitate removing the boom cylinder or boom. Of course, this varies with different excavators; if the front support point is convenient and does not require moving the undercarriage, disassembly may not be necessary. Although beam support also requires auxiliary supports, they typically do not require disassembling cylinders or booms due to different force distributions. Additionally, a locking device is essential for hydraulic jacks to prevent safety hazards.

Undercarriage Hydraulic Power Unit

Typically, after separating the upper and lower parts of an excavator, the undercarriage section loses power and can only be moved by pushing or pulling with other equipment, posing safety hazards. The undercarriage hydraulic power unit effectively addresses this issue. Consisting of a small engine, hydraulic pump, hydraulic tank, and control system, this unit is installed on the undercarriage and connected to the excavator's travel motors via pipelines, enabling independent movement of the undercarriage.

Hydraulic Cylinder Hoisting Tool

Disassembling and installing large hydraulic cylinders, especially those located beneath the boom, such as the bucket cylinder, is challenging. Direct operation with a crane from above is inconvenient, while working from below with a loader is unsafe. This specialized hydraulic cylinder hoisting tool is mounted as an attachment on a telescopic forklift. Typically, a forklift with a capacity of 10 tons is needed for handling 7.5-ton hydraulic cylinders. Under remote control operation, this tool can easily adjust position, direction, and angle to facilitate disassembly and installation while ensuring safety.

Additionally, apart from the expensive solution mentioned above, there is a cheaper alternative known as the cylinder positioning tool, which only requires a crane for operation.

Hydraulic Pump Lifting Tool

When it comes to disassembling or installing hydraulic pumps, there's often no need for extensive dismantling to facilitate crane lifting. In such cases, a simple tool suffices. Although this tool may lack sophisticated technology, it proves highly practical and efficiently enhances maintenance work.

Track Pin Removal Tool

Despite their small size, track pins are tightly designed, making them difficult to remove. Traditionally, this process required heating with an oxy-acetylene torch and sometimes welding, causing significant damage to the track structure. Now, a hydraulic-powered tool offers a smooth method to extract track pins, allowing for easy track removal. Currently available in two specifications generating forces of 200t and 500t, suitable for excavators with chain-type tracks up to 400 tons. This method is simple, safe, efficient, and preserves the integrity of the tracks.

Idler Wheel Installation Tool

The idler wheel installation tool is essentially a simple bracket. Previously, replacing damaged idler wheels was complex, typically requiring the removal of tracks and supporting the undercarriage for replacement. With this tool, the process is simplified significantly. By loosening one side of the track and supporting the machine with a bucket to suspend one side of the track, two idler wheel installation tools can be placed. Then, lowering the machine back onto the ground allows for safe idler wheel replacement. Though straightforward and lacking technical sophistication, this tool is highly practical.

The aforementioned tools are developed by either the equipment manufacturers based on the users' specific needs or by third-party developers to ensure compatibility across various brands and models of excavators. While some may lack technical sophistication, they remain highly practical. Globally, there is a shortage of skilled labor and high labor costs, particularly in remote mining areas. Moreover, the pursuit of efficiency has led to increasingly shorter maintenance cycles, with safety being paramount. Choosing the right tools can significantly enhance productivity and safety while also optimizing costs.

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