JCB is now installing a piston pump on Tier 4 machines and marrying the pump and the engine together through the ECU.
John Deere offers a variety of backhoe controls to suit different customers and applications. K-Series backhoes also offer operators a choice of several operating modes such as Economy Mode, Auto Idle and Auto Shutdown.
Providing operators with the control pattern, digging position and control feel they prefer is essential. That’s why New Holland continues to offer pilot and two-lever controls on the C-Series backhoe-loaders.
The Caterpillar F Series models feature an electronically controlled piston pump that automatically optimizes performance for specific operations, ensuring loader power management and backhoe productivity.
Advancements in backhoe-loader controls have increased the options available. To make the best choice for your needs, you first must understand what’s available and the advantages and drawbacks of each system.
Backhoes are constantly evolving. “Most recent innovations — such as excavator-style joystick controls, pattern changer valves and ride control systems — focus more on efficiency, controllability and ergonomics,” says Curtis Goettel, brand marketing manager, New Holland Construction. “These innovations not only help make the operator more comfortable and productive, they also allow for faster working speeds from higher flow rates, more effective engine power, greater fuel efficiency and minimized engine overloading or stalling.”
He adds that it’s essential to provide operators with the control pattern, digging position and control feel they prefer. “Less experienced backhoe-loader operators who may have previously worked on excavators, for example, will have a different feel for the controls than the more experienced operator who may choose a more ergonomic style of operation,” he points out.
This is why several control options are typically available. “Control options provide the operator with greater, more precise control with less effort, making them more comfortable,” says Goettel. “And a comfortable operator is a productive operator, especially when working in tough conditions and on jobs like digging trenches or placing pipes.”
To accommodate operator preferences, New Holland offers pilot and two-lever controls on its C-Series backhoe-loaders. “The pilot control option, which is growing in popularity, provides infinite forward and reverse movement,” says Goettel.
“For owner operators, the feel of the backhoe can be a primary factor in the purchase decision,” says Sherrie Carter, backhoe-loader product marketing, Caterpillar. “It’s why Caterpillar spends a significant effort during the product development on hydraulic tuning. This involves intricate work on hydraulic valve spools to create smooth modulation, balanced multi-function performance and quick response to operator inputs. Good tuning enables the operator to work confidently in applications like fiber optics, yet be very efficient in production trenching operations.”
Open or Closed?
JCB introduced servo controls on its backhoes in the mid-’90s. “The whole reason to go to the servos from the mechanical levers is to reduce operator fatigue,” says Jim Blower. “You push the lever less distance and it takes less effort to push it.”
Operator comfort is directly linked to productivity. “Pilot-operated joysticks offer primarily ergonomic advantages,” says Carter. “But the reality is that, in an eight- to 10-hour day, those advantages can translate to more work done simply because the operator is less fatigued.”
“Before servo controls came along we had manual controls through the levered link through the valve block,” Blower indicates. The move to servo controls required some changes. “The manual controls have an open-center circuit and a full-flow valve block.” Early servo controls required a move to a closed-center hydraulic system and flow-sharing valve blocks.
Open-center and closed-center systems each have unique operating characteristics. “Open-center circuits give the operator a feel for a backhoe,” says Blower. “If you dig a trench with an open-center machine and you encounter an obstacle and you want to power through it, you pull the lever a little bit further to increase the pressure. This increases the breakout force of the bucket edge. The operator has to do something (i.e., move the lever) to increase the pressure. When you go to a closed-center system and encounter an obstacle, the machine senses the resistance and increases the pressure automatically to increase the breakout force.”
The decision as to which system is better really depends on your application and operators. But if there is a pipe or service in the ground and the operator wants to feel when he reaches it, an open-center-style machine makes it possible, says Blower.
Another advantage of mechanical controls with open-center systems is the use of a full-flow valve block. “If you have 100 gpm in a circuit and you pull one lever, you get 100 gpm going to that one circuit,” Blower states. Or you can have 80 gpm going to the boom and 20 gpm going to the dipper. “You are just juggling levers and putting the flow where you want it.”
Compare this to the flow-sharing valve block where the amount of oil to each cylinder is limited. In the example of the 100 gpm circuit, it may only allow 50 gpm to the boom and 50 gpm to the dipper. “So it is slowing the boom circuit by half. Overall, it’s easier for the operator to multi-function with the flow-sharing valve block, but it slows the cycle time because you can only get 50% flow at any one time.”
To address these trade-offs, JCB gives operators the choice of three distinct control options: manual controls with an open-center system and full-flow valve block; EasyControl servo controls with an open-center circuit and full-flow; and, the most recent innovation, Advanced EasyControl servos with a closed-center circuit and flow-sharing valve blocks.
The EasyControl offers the benefits of manual controls coupled with servos. “We put servos onto a system with open-center to get the feel back and a full-flow valve block to get the speed back,” says Blower. “So you can have the comfort of the servos with faster cycle times. With the Advanced EasyControl, as you spin the seat to face the front, the right-hand control becomes the loader lever, giving a servo-controlled loader, as well.”
Fewer, More Intuitive controls
“Whether you are in the seat of a backhoe all day, or you are jumping in the seat quickly for a few minutes as you complete a task on the jobsite, controls need to be intuitive and easy to operate to provide the most efficient experience,” says Louann Hausner, backhoe-loader product marketing manager, John Deere Construction & Forestry. “The feel of the controls has evolved into being the need for a control that acts as an extension of the operator’s hand, enabling the operator to have multiple functions at their fingertips without searching and reaching within the cab.”
The benefits of smart controls that are ergonomically placed exactly where an operator needs them include increased fuel efficiency and productivity. “Operators can accomplish more in less time with less fuel by having controls [that are] easy to learn and operate,” says Hausner. “With Deere’s loader control eliminating the need for an additional lever and buttons on the side console, operators can focus more attention on the task instead of searching for controls and juggling the coordination of two levers in one hand.”
John Deere offers a variety of controls to accommodate a wide spectrum of users. “Loader controls vary by customer need,” says Hausner. “Regardless if customers are doing the basics and controlling only the two key functions of lift and bucket, or if they are maximizing the use of a multi-purpose loader bucket, Deere offers a single-lever control to meet all needs.”
For example, the new loader control combines two levers into one easy-to-grip control. “This loader control provides additional functionality, including momentary MFWD and proportional auxiliary hydraulic control, which is needed for multi-purpose buckets,” says Hausner. All controls are at your fingertips. “Tire wear is reduced because operators will use MFWD only when needed to get the job done.”
A selection of backhoe controls is also offered. “With mechanical, hydraulically-driven pilots and electrohydraulic controls integrated into the armrests of the seat all available depending upon the model, Deere can provide the variety customers need,” says Hausner.
In addition to the control options, John Deere provides enhancements to improve efficiency of the entire operation. “Deere has brought smart features such as Economy Mode, Auto Idle and Auto Shutdown to customers with the K-Series backhoes,” says Hausner. “Economy Mode enables the backhoe to operate at optimal fuel economy and productivity, while Auto Idle and Auto Shutdown reduce overall fuel usage when idling. Both have a very positive impact to the customers’ bottom line.”
Caterpillar offers both mechanical and pilot controls on its backhoe-loaders. While pilot controls are the most popular, some operators still prefer the long-standing mechanical controls. “The Cat 416 offers mechanical backhoe controls (or wobble sticks), which include attached foot pedal controls for auxiliary functions,” says Carter. “The 420, 430 and 450 offer pilot backhoe controls. The operator has the ability to select the preferred pattern by a flip of a switch inside the cab.”
Thumb rollers for auxiliary functions are provided on Cat backhoes with pilot controls. “These roller switches enable the operator to control all backhoe functions with the joystick controls and eliminate the need for foot-operated pedals, providing extra foot space and leg room for the operators,” says Carter. “In addition, the controls provide smooth modulation for precise operation of work tools like hydraulic thumbs.”
She adds, “Other controls on Cat 420 and 430 backhoes enable Automatic Engine Speed Control (AESC), a fuel-saving feature, and a manual kick-down switch that allows the operator to instantly reduce engine speed to low idle for communication with ground laborers. On machines with auxiliary functions, a continuous flow switch allows the operator to select and lock in flow to the tool without constant operation of the roller switches. This is a great benefit for loader tools like brooms, and backhoe tools like augers, compactors and trash pumps.”
Caterpillar offers mechanical and pilot controls for the loader, as well. “Both offer the ability to operate a multi-function bucket on the front end,” says Carter. “With the pilot controls, you gain a thumb roller on the joystick that operates the auxiliary functions, including additional loader work tools.”
Gains in system efficiency
Load-sensing piston pumps have been migrating from the excavator to the backhoe-loader as more emphasis is placed on efficiency.
Caterpillar backhoes have historically included load-sensing hydraulics with variable-displacement piston pumps for productivity and fuel economy. “On our new F Series machines, we introduced an electronically controlled piston pump,” says Carter. “The pump automatically optimizes performance for specific operations — for loader power management, and for backhoe productivity. In addition, the electronic control provides better pump response, which has contributed to productivity increases.”
JCB has also made a few changes to improve backhoe efficiency. “In the Tier 3 machines, we were still running gear pumps,” says Blower. “But we added a third pump into the system so the operator could reduce the engine revs from 2,200 rpm down to 1,600 or 1,700 rpm. We made up for the lower rpm by adding a third pump to make the flow the same. The pressures are all the same. By reducing engine rpm, we reduce fuel consumption by about 16%.”
Moving to Tier 4i, the engine is now electronic and is controlled by an ECU. To take advantage of this new capability, JCB is installing a piston pump and marrying the pump and engine together through the ECU. “So at each stage of the evolution, we are looking at more efficiencies throughout the machine,” Blower comments.
“The piston pump is more advanced, so they are a little more expensive for the initial purchase price,” he acknowledges. “But the cost between a piston pump and a gear pump has reduced dramatically over the last 10 to 15 years.”
A piston pump also calls for some additional TLC. “The piston pump is a little more complex. It requires a little finer filtration of the hydraulic system to make sure you get all the dirt out,” Blower notes. “You have to watch the cleanliness of the oil when you use the piston pumps.”
New Holland’s C Series backhoe-loaders with mechanical backhoe controls continue to feature a single gear pump open hydraulic system. However, the pilot backhoe controls on C Series models deliver improved fuel efficiency and cycle times via a variable-volume hydraulic system. “This system operates at a lower temperature,” says Goettel. “The variable-volume pump feature means lower fuel consumption each day, faster operating times and more productivity at lower costs.”
As you can see, backhoe-loader manufacturers offer a diverse choice of controls that is expanding with the new capabilities provided by the advent of electronic engines that meet Tier 4 requirements. The key lies in identifying which control system is really the best fit for your operators and application.