May 2016, Vol. 71 No. 5
Features
Track Trencher Maintenance Crucial To Up-Time
Underground Equipment Maintenance: Track Trencher Maintenance
Operation of any type of construction equipment results in wear of essential components. Regular track trencher maintenance and replacement of worn parts when necessary keeps equipment productive and extends a machine’s service life.
Wear varies greatly with the type of equipment, its functions and how it is used. But few construction machines are subjected to harder use than big rock trenchers. Preventive maintenance – sometimes at intervals more frequent than specified schedules – is essential.
Representatives of three manufacturers of large trenchers frequently used to dig deep, wide trenches in demanding conditions recently discussed care and maintenance with Underground Construction.
Tesmec USA, Sergei Edwards, field engineer
Tesmec offers a variety of rock cutting machines that fit in three distinct categories: rock saw, chainsaw and surface\mining bulk excavation. Each category offers a selection of trencher models, depending on the customer specifications, ground conditions and trenching requirements. The categories differ from each other in terms of overall dimensions and weight of the machine, and trenching width and depth
capabilities.
In difficult environments, rock trenchers may require more frequent intervals of scheduled maintenance if operated in such conditions. For example: temperature (extremely high or low), altitude, salty seaside environments and situations with excess dust.
The only components that will require more frequent maintenance checks on the rock trenchers, as compared to other heavy duty construction machinery, would be the wear components. The frequency of repairing or replacing these components is directly related to the abrasiveness of the material the machine operates in.
The importance of performing regular preventative maintenance in the field is crucial, not only from the efficiency point of view, but also from an economical point of view. Every maintenance check that is mentioned in this section can be performed in the field on all Tesmec trenchers.
Rock digging teeth are constructed from high-strength steel shanks with carbide tips and must be inspected regularly throughout the day. Broken, worn-out or missing tips must be replaced as soon as possible to avoid damage to other components. Teeth must be replaced when their carbide tip splinters or breaks off and when a tip becomes round, flat or dull. Failure to replace worn-out teeth will result in severe pocket wear as well as increased
segment wear.
Digging chain lifecycle is related directly to the abrasiveness of the material in which the machine is operating in. It is advisable not to use the chain up to its breaking point, but to change it in advance in order to prevent damage to other components. A crucial factor to monitor is the chain’s sag, or the operating tension.
Digging boom wear plates must be replaced periodically to avoid damage to the boom. If the wear plate is worn so the digging chain can reach the digging boom structure, the wear plate must be rotated or replaced.
Tool holder and baseplates are provided with a hard metal coating applied on their exposed projected areas. This coating must be preserved to maximize the life of the tool holder and baseplates.
Undercarriage sprockets, track chain and rollers – During operation, materials can stick to and pack between mating components such as rollers, chain links, sprocket teeth and bushings. Material that builds up between the track links potentially can harden similar to concrete. Packing prevents parts from engaging correctly which can cause higher loads and increased wear rates.
Track chain tension – Track chains are linked by pins and bushings which move independently of each other allowing the track chain to rotate around the sprocket and front idler. The movement of pins and bushings takes place four times per revolution of the track chain resulting in internal pin and bushing wear and is influenced by dirt and moisture. It is important to keep tracks at the correct tension.
Conveyor belts must be inspected for excessive wear signs and that the belt tension is correct and adjusted as necessary. Tension that is too high may cause friction between the belt and the side sills; this creates a drop in performance along with premature wear. Belts that are too loose may cause driving drum slippage.
Most neglected maintenance – Our experienced service personnel say the most neglected maintenance is failure to lubricate. Second is chain adjustments.
Trencor, Jeff Seidl, development specialist
Trencor currently offers five rock trencher models ranging from 350 to 950 horsepower, all with mechanical trencher drive. We provide recommended maintenance for our equipment, but more frequent service is required when working in hard, abrasive rock, other subsoil conditions, rough terrain and extreme climates. Typically, there is much less wear when working in dirt.
There are different types of carbide cutting tools to accommodate different conditions. We use specific patterns tailored to give maximum production at the lowest cost per foot. Teeth should be inspected hourly during operation, sometimes even more often. Changing individual teeth occurs throughout operating time as they wear beyond useful life or a pattern change is required. Tooth holders or pockets, cutter bars and boom wear plates require attention.
To keep up-time at a high level, preventive maintenance can be performed in the field. Digging chains can be changed in the field, but ideally it should be done at scheduled downtime in a shop facility. Track maintenance is low other than adjusting them properly and cleaning after use.
It is recommended a rock trencher go into the shop annually or every 2,000 hours. Most neglected maintenance items are grease points, hard surfacing of base plates and boom and chain adjustment.
Vermeer, Chris Lynch, mining and pipeline sales manager
Vermeer manufactures three rock trencher models ranging from 415 to 600 horsepower, all with hydraulic trencher drive. It is not a matter of if a rock trencher will have demanding scheduled or unscheduled maintenance needs – it is a matter of when. The most important thing an operator can have access to is service personnel and parts. A trencher works under full load in very demanding conditions, which is a challenge most machines in other applications do not face.
Chain and teeth – There are a variety of chains available based on the horsepower of the trencher and the desired width of the cut. Chains are a wear item and their life is ground condition–specific. Chains should be maintained and replaced according to the manual.
Teeth are a different subject altogether. There are hundreds of options based on the material cut and the size of the trencher applied. In general, a tooth should be replaced when the carbide tip is worn out or worn to a point where it no longer effectively penetrates the rock.
Service requirements and intervals are spelled out in each product’s maintenance manual. However, many maintenance requirements and intervals are condition-specific. In hard-rock applications, a trencher attachment chain will need to be checked and adjusted more frequently. In dusty conditions, air filters will need to be replaced more often. These are just a few examples.
Base plate and sockets – Something that is often overlooked is the base plate and pocket maintenance on the trencher attachment. In hard/abrasive conditions, base plates and pockets wear rapidly. Daily inspections and routine hard facing are a must in these conditions. It is not unusual that many hours must be devoted daily to hard facing and, when necessary, pocket replacement.
Field maintenance – In most cases, preventive maintenance can and will be performed in the field with a service truck. It is only in major overhauls and breakdowns that a unit must be transported back to a service facility. Chains can be changed in the field, and this is routinely done, but it is easier to accomplish in a service center. The tracks on a trencher do not wear as rapidly as tracks on other equipment because, when in use, a trencher moves in one direction, at a much slower speed, under a continuous high load.
Shop time – In the case of Vermeer hydrostatic machines, the hydraulic oil change interval is typically 1,000 hours. Ideally, this maintenance task will be done in a shop to reduce the possibility of contamination.
Often neglected – Tooth replacement always is a challenge. Frequent stops to check tooth wear can negatively affect production, but neglecting to proactively replace teeth can reduce productivity due to pocket replacement.
Also see first article in this series:
Complexities Of Modern HDD Make Directional Drilling Rig Maintenance Even More Important
FOR MORE INFORMATION:
Trencor,
(800) 324-4930, www.americanaugers.com
Vermeer Corp.,
(888) 837-6337, www.vermeer.com
Tesmec USA,
(800) 851-5102, www.tesmec.com
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