Shuttle shift transmissions allow the machine to shuttle easily from forward to reverse, which is especially beneficial in stockpile applications.
A backhoe-loader can be used to perform the tasks of both an excavator and a wheel loader, maximizing utilization. But there is a compromise for this versatility.
A backhoe-loader will not out-produce a mini-excavator in a pure trenching application, nor will it out-produce a wheel loader in a loading application, says Jim Blower, senior product manager, JCB. But the machine can do both and has additional benefits as far as road speed to get between jobs.
While many applications are weighted heavily on the backhoe end, front-end capabilities are what really add to the versatility of these machines. Fortunately, there are many features available to enhance such performance specs as breakout force, lift capacity/force, dump height and reach and more.
Traction speeds cycle times
Several options will enhance loader work, depending on the operation at hand, says Bob Tyler, John Deere. Four-wheel drive is the most obvious for enhanced traction in loose or sticky conditions. It can even reduce tire wear in dry conditions, where spinning is reduced due to the increased grip.
The added benefits of a limited-slip front differential can also keep you going where an open differential might not, he continues. The limited-slip design gives you more traction because both front wheels are pulling, as opposed to just one with the open differential.
Four-wheel drive allows the loader bucket to be filled more quickly. This reduces loading cycle times, which means a pile can be moved quicker, a load can be loaded faster or a trench can be filled in less time. The four-wheel-drive backhoes have more tractive effort, which delivers better pushing power and more production in sloppy and wet conditions, states Paul Wade, inside sales manager, New Holland Construction.
Most of our customers do not have the luxury of operating on smooth, solid surfaces, notes Keith Rohrbacker, construction equipment product manager, Kubota. Proper tire selection helps, but four-wheel drive provides the traction required for operating on rough, uneven surfaces or for operation on slopes, grades and hills.
Using four-wheel drive along with rear-wheel differential lock is essential when work must go on during and after the rainy season, he adds, providing smooth and sure starts and stops ? essential control required when working around personnel in tight spaces.
In addition to four-wheel drive and four-wheel steering for maneuverability, JCB offers a torque proportioning differential to provide traction even in difficult conditions, plus limited-slip steer drive axles front and rear. Some machines also have four equal-size tires to increase ground clearance and provide better flotation for loader work.
For the operator that would like to do more loader work with their machine, JCB offers a 4CX, which is a machine that has larger front wheels, says Blower. That adds stability in loader applications, as opposed to the traditional machines, which have smaller wheels on the loader end.
Keep the machine
Weight distribution between the front and rear axles has a dramatic impact on loader performance.
Balance is extremely important when doing front-end loader work, says Wade. When the machine isn?t balanced correctly, you tend to lose your load.
If too much weight is on the rear end, the front-wheel drive may not be able to get proper traction and may slip, giving less traction and more tire wear, Tyler explains. Steering can also become less effective. Conversely, if too much weight is on the front, then the steering can become heavy under load.
Machines have to be balanced for all applications ? backhoe, loader and road transport, Blower adds. Too much weight on the front will increase tire wear in road transport and loading applications. Not enough weight on the front will mean the front of the machine will pick up in tough backhoe applications.
Every time something is added or taken off, the machine should be re-counterweighted, he advises. This includes adding a hammer, changing a general-purpose bucket to a 6-in-1, adding [an extendible dipperstick], etc.
To help achieve optimal balance, John Deere provides a counterweight chart that recommends the right amount of counterweight based upon the options chosen when you order a machine. For example, you would need more weight on the front if you were going to use a hammer with an extendible dipperstick, notes Tyler, but less weight on the front if you require a multipurpose bucket on the loader and a standard dipperstick behind.
makes a difference
If you anticipate significant loader use or roading of the machine, then a powershift transmission may be the answer. One advantage to a powershift transmission is that the operator is able to smoothly transition speeds, says Wade.
Other advantages include improved load retention and greater overall productivity. Powershift transmissions make changing gear a lot easier for the operator, says Blower. Anything that makes the job easier for the operator leads to more productivity.
JCB offers an Autoshift transmission as an option on its backhoe-loaders. According to Blower, the operator can select second gear to increase cycle speed for truck loading. Then, as the machine approaches a pile, a button on the floor can be depressed to kick the transmission down to first gear to load the bucket. Once the machine is put into reverse, the transmission reverts back to second gear to maintain cycle times.
The Autoshift transmission can also be put into a fully auto mode for roading applications, he adds. A locking torque converter maintains the road speed when traveling between jobsites.
Shuttle shift transmissions can also be very beneficial. Shuttle shift transmissions mean the machine can be shuttled from forward to reverse without grinding gears, says Blower. It is accomplished through hydraulic clutch packs.
Having to reach over and change gear on every cycle when truck loading would be very fatiguing, says Tyler. A powershift transmission that includes a shuttle shift (or FNR lever) allows easy gear changes by simply rotating the collar on the FNR lever ? no need to bend forward to reach a gear lever or pull and push it in or out of gear.
Retain the load
Ride control is a valuable asset for load and carry or road transport applications. Ride control will allow the backhoe to travel across the jobsite more quickly without spilling material, say, from the gravel pile to the trench, says Tyler.
When ride control is engaged, an accumulator is brought in to the loader hydraulic circuit. The loader arms then act as shock absorbers, leveling out the bumps across the jobsite, he explains. This also makes roading faster. The backhoe can ride through undulations in the road without slowing when transporting between one jobsite and the next, for example.
Of course, ride control does add cost to the base machine, so you need to perform sufficient loader work to earn a return on investment.
Other features can further adapt backhoe-loaders to load and carry applications. Take hydraulic self-leveling. Hydraulic self-leveling loader control valves improve pallet work and are easily shut off, with a conveniently located lever, for loader work, says Rohrbacker.
True parallel-lift loader arm designs are another example. A parallel-lift loader arm configuration gives you self-leveling and more reach when dumping into a truck, says Wade.
All JCB 3CX and 4CX machines come standard with a parallel-lift loader, says Blower. When used in a fork application, the forks will stay parallel to the ground through the whole lift and lower cycle.
John Deere?s TMC backhoes rely on electrohydraulics vs. mechanical linkages to provide the parallel-lift function. TMC machines have the ability to turn parallel lift off and re-engage self-leveling, says Tyler. This is so the parallel lift action is not fighting the desire to have the bucket fully curled to keep contents from spilling, while retaining the bucket self-leveling action near full height when truck loading.
No loader lift force or bucket breakout force is lost on Deere TMC units, he adds, since they use larger loader and bucket cylinders to actually increase these specs as it?s likely the front end will be used more with this configuration.
Visibility to the front of the machine is also an issue in loader applications. Certain designs may offer a better view than others.
A braceless loader frame improves visibility when operating in confined spaces, and to the quick coupler to speed attachment changes, Rohrbacker asserts.
New Holland backhoe-loaders feature slim cab pillars and sloped hoods for greater visibility to the front edge of the loader bucket. And for fast, easy attachment hookup, an optional auxiliary hydraulic circuit can be used with a mechanical quick-attach system or an electrohydraulic quick coupler.
A hydraulic quick coupler gives the operator the ability to quickly change out attachments like 4-in-1 buckets, street sweepers and forks, says Wade. It allows the backhoe to be one of the most versatile machines on the jobsite.
A good hydraulic quick attach can quickly pay for itself through increased machine utilization. The changeover time between buckets and forks can be as little as 20 seconds, says Tyler, so there is minimal downtime when changing attachments.