The extendible dipper stick can add 5% or more to the cost of a backhoe-loader. But it also extends machine reach, increasing the size of the workable trench. This allows you to dig a longer flat-bottom trench without having to reposition the machine, which improves productivity. It also allows the operator to place the spoil farther from the trench.
“Typically, extendible dippers add 3 to 4 ft. of reach,” says John Comrie, competency manager, utility products, Volvo Construction Equipment. “The extendible dipper will pay for itself in productivity gains, as the machine does not need to be moved as often when digging trenches or loading spoil/debris on truck beds.”
Jim Blower, senior product manager – mid-range, JCB, notes, “The greatest return is really in a trenching application. The biggest advantage is that you can set the machine up, reach farther out and dig along the trench from one position. The more time you spend moving the machine, the less time you spend digging. You just reduce the amount of machine movements and increase the amount of digging time.”
The extendible dipper stick also allows you to reach into areas inaccessible to a standard dipper. “In circumstances where dig depth changes, this dipper provides instant access to a deeper flat-bottom trench,” says Rob Marringa, marketing manager, Case Equipment. “In applications where the backhoe is being utilized as a lift and position tool, the extendible attribute increases control for finite positioning.”
There are as many answers as to what you can do with an extendible dipper as there are backhoe operators. The larger the percentage of the work you perform with the back end of the backhoe-loader, the easier it may be to justify the extendible dipper stick.
“Having a standard boom and dipper simply limits the scope of flexibility,” says Marringa. “In some cases, it may be necessary to bring in an additional machine that can serve the needs of the entire jobsite, thereby increasing costs of site work and delaying job completion.”
Admittedly, an extendible dipper weighs more than a fixed dipper.
“Every machine is a little different, but it is about 500 lbs. extra that you carry on the back end,” says Blower. “When you add more weight to the back end of the machine, you have to make allowances for it by [adding] different counterweights on the front to balance it up again so when you are going down the road, you are not bouncing the front tires off the ground. Every time we build a machine, we balance it back up again.”
The extra weight can reduce lift capacity. “You are carrying that weight on the back, so you do reduce slightly the amount you can lift,” says Blower. “It depends on the geometry of where the extra weight is actually being carried.”
“The additional weight added by the extendible dipper puts a standard dipper in an advantageous position as it relates to lifting when the dipper is extended,” says Marringa. “As far as digging applications, the condition is arguable based upon the job being performed, as breakout capacities and bucket rotation are not affected by this option.”
Conrie insists the versatility and productivity increases of extendible dippers far outweigh any drawbacks. “There are virtually no disadvantages in equipping a machine with an extendible dipper,” he comments. “The loss in lift capacity with an inner slide design is very minor. Although the owner may pay additional for this feature, he will recover it in a short time through productivity gains.”
One way is through increased attachment versatility. While some manufacturers previously advised against using hammers with extendible dippers, for the most part, this is no longer the case.
“Hammers are approved for use with a JCB ExtraDig machine,” says Blower, adding that there are no backhoe attachments not approved for use with these machines. But the ExtraDig should be locked up in a retracted position for hammer use. “There is no excuse to use a hammer with an ExtraDig that is extended way out. You will just increase the wear on the slides.”