The recent take off of the front mounted hoe, designed to be used on articulated tool carriers has spread even more doubt about the usefulness of the backhoe on modern job sites.
The following article illustrates 6 points of difference between an articulated front end loader and a backhoe on the job site in material handling.
1. Maneuverability. Articulated front end loaders allow the operator to work in confined areas. Articulated steering is similar to having two very short machines attached together with a rod, so really you are operating a very short machine and the other chassis follows behind. Backhoes on the other hand have a rigid chassis and are no-where near as maneuverable as a modern articulated front end loader. This ability of articulated front end loaders to operate in confined areas allows you to gain access to places you couldn't with your backhoe. The higher utilization rate of articulated front end loaders pays off with less jobs having to be performed manually. The superior all around visibility in a compact articulated front end loader also makes productivity in confined areas much higher as the operator isn't constantly concerned about damage to buildings, machinery, personnel or animals constantly on the job site. In a backhoe the engine obscures a lot of vision at the front and the rear is obscured with a folded up excavator mast.
2. Steering under load. Articulated front end loaders utilize strong rams to pivot the whole front chassis which steers the vehicle in the required direction. The powerful steering is required because under load the centre of gravity shifts approximately 2/3 of the whole machine onto the front axle, making it heavy under load if the steering isn't suitable. Backhoe's however are a compromise between an excavator and a loader and are built on a tractor chassis, with a front mounted engine. Backhoes generally have big wheels at the back for stability when the excavator arm is in use. This type of chassis design is taken from agricultural tractors which are designed to tow - this is the reason the big wheels designed for heavy loads, are mounted at the back and the small wheels, which are easier to steer, are mounted at the front. When the loader bucket is filled, the backhoe's centre of gravity shifts onto the front wheels and axles and CV joints, making it hard to steer. The CV joints must be made extremely strong for this reason as they take a lot of punishment when front loading, really the chassis is not optimally designed for this role in the first place. Articulated front end loaders however have rigid axles so they don't have any CV joints to get damaged, when the centre of gravity shifts forwards when loading - the steering is controlled by articulating the whole front chassis. This is just another reason showing that articulated front end loaders are truly designed from scratch for loading, particularly in the long run when maintenance costs are taken into account.
3.Loading speed. Backhoes can be used on job sites for loading trucks, however when you load with a big backhoe you waste a lot of diesel compared to loading with an articulated front end loader that is designed for loading. To operating a backhoe you need a lot of space to get in the right position to load and then to dump into the truck. The truck must be parked much further away from the pile of material to be moved as the tractor has limited maneuverability.
On the other hand articulated front end loaders operate easily in very confined areas so they don't need to travel as far to dump and get in the right position to load again. This is due to the very tight steering angle - one of the greatest advantages of an articulated vehicle. The most efficient compact articulated front end loaders on the market now have articulation angles of 47 degrees. Smaller articulated front end loaders, generally under 1750kg, have articulation angles of 60 degrees as they don't incorporate a drive shaft so the articulation angle can be made much higher.
The high articulation angle of modern articulated front end loaders allows them to easily manoeuvre in tight areas with ease to load trucks a lot faster, saving a lot of time and diesel compared to using a backhoe. Many people believe that an articulated front end loader, only half the size of a backhoe, will still load a truck faster. If this is the case, then you are using half the diesel, making incredible day to day savings in time and money.
4.Low operating height. Some modern compact articulated front end loaders are built with very low operating heights. Backhoes however have very large rear wheels and are made incredibly wide to give stability for the excavating hoe. Compact articulated front end loaders are much narrower and allow access to more areas on a construction site. This low height and narrow width allows access into buildings and demolition sites for construction and removal of debris, giving a higher utilization rate for the owner.
The low height and relatively narrow width of articulated front end loaders when further coupled with the extremely tight turning circle gives even more accessibility in confined spaces. The low operating height also gives another benefit not realized at the beginning - the easy access for personnel to the cabin area means they get used constantly, for all jobs, as they are so convenient. Backhoes due to their large wheels at the back must have high cabin heights and constantly getting in and out can be chore, particularly for smaller tasks, so often the job is done by hand. Another advantage of the low height of compact articulated front end loaders is, when floating loaders from job to job, the total transport height is significantly lower and permits don't need to be obtained.
5.Centre of gravity. Articulated front end loaders are designed to maximize the efficiency of the weight they can lift at the front of the machine. The placement of counterweights and the longitudinal centre of gravity on an articulated front end loader, are designed completely differently to that of a backhoe. Articulated front end loaders incorporate weight, as far behind the rear axle as possibl, to make lifting at the front efficient. Significant weight as far out the back of the rear axle as practical, makes it possible to lift higher amounts at the front of the articulated front end loader due to the simple lever principle - the more counter weight out the back, the more effective it will be. Articulated front end loaders when unloaded have approximately 2/3 of the total machine weight resting on the rear axle, however when loaded the centre of gravity shifts to 2/3 of the total weight on the front axle.
Backhoe chassis on the other hand are built completely differently - one of the biggest differences being weight distribution - the engine is mounted at the front of the machine, as this style of chassis was originally designed for towing in agricultural use. The engine and a lot of counterweight is mounted at the front as the backhoe's excavator arm needs to be balanced on the backhoe. The longitudinal centre of gravity of a backhoe is closer to a 50/50 weight distribution on the front and rear axles. No matter how much weight is added to the backhoe, it will always be inefficient for front loading compared to an articulated front end loader due to the initial design of the backhoe. This means the tractor engine must shift a lot more weight when completing all loading tasks, creating more ground disturbance and compaction, greater tyre wear, axle wear and fuel consumption during loading.
6.View of front end when operating. Compact articulated front end loaders have a great view of the front end as this is where all the work occurs and the driver must have a great view if they are to perform work quickly and safely. The front chassis on an articulated front end loader is minimized in size and weight so maximum visibility is created for the driver. The mast is also designed to be as streamlined as possible so no interference occurs to the drivers view and anything else that could obstruct the view has been placed behind or underneath the driver eg. the engine.
The view from the front end of a backhoe is totally different - the forward mounted engine totally obscures the front working area so it is very difficult to see the working face and more guess work and less precise work is then performed with a backhoe compared to an articulated loader. Also the arms of the loader must be designed to go around the engine, making them bulkier and further obscuring the view.
I hope this summary has been of use. It really only illustrates some of the difference between purpose built articulated front end loaders and backhoes. Increasingly around the world diesel prices and labour costs are rising so productivity needs to be maximized. The range of hydraulically operated tools that can be operated by articulated front end loaders are now over 50 strong but that is a whole new topic!
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