Equipment Type

Controls Refine Great Skid Steer Loader Power

Even with a broad range of weights and horsepowers represented within a fairly narrow segment of skid steer loaders available today, most equipment manufacturers are relying on the same features — operator stations, hydraulic performance, and attachment versatility to differentiate their mid-sized machines.

May 01, 2006

 

Bobcat skid-steer loader
K-Force hydraulics improve available hydraulic horsepower on all of Bobcat's mid-sized skid-steer loaders by 8 percent, providing better breakout force and attachment power.
Case 400 Series skid-steer loader
The ROPS/cab on Case's 400 Series tilts in 10 seconds for open access to the engine and major hydrostatic components under the operator's compartment. Case 400 Series skid-steer loaders have a single location for all daily service checks.


 

Even with a broad range of weights and horsepowers represented within a fairly narrow segment of skid steer loaders available today, most equipment manufacturers are relying on the same features — operator stations, hydraulic performance, and attachment versatility to differentiate their mid-sized machines.

The 32 models of mid-sized skid-steers — spanning just 600 pounds of rated operating capacity between 1,600 and 2,200 pounds — include machines with net engine horsepowers ranging from 44 to 82, and operating weights from 5,500 pounds to 7,700 pounds. With standard hydraulic-pump flows ranging from 15.5 to 23 gallons per minute and pressures from 2,400 to 3,450 psi, hydraulic horsepower stretches from 23 to nearly 43. Bucket breakout forces for mid-sized skid-steers run the gamut from 2,900 pounds to more than 7,500 pounds, and arm lifting forces from 2,800 to more than 6,800 pounds.

Within a narrow size class, other types of construction machines — backhoe-loaders, wheel loaders, excavators — don't show such wide spreads in performance. When brochures for these more homogeneous machine types wax eloquent about the comfort of their cabs and convenience of their controls, it seems like an indication of parity between competitors' basic performance specifications.

Perhaps skid-steer manufacturers are telling similar stories about their control systems and cab ergonomics, even when their specifications span broad gulfs in performance, because of the difference in size of the skid-steer market.

There are 281,700 skid-steers at work in the United States, according to Construction Equipment's 2003 Universe Study. That's 27,000 more units than backhoe-loaders, the next most populous machine type, and 1.6 times as many wheel loaders. Apparently there are enough skid-steers sold in enough different applications to support various combinations of weight, horsepower and hydraulic performance. So manufacturers cite controls and cabs as the most significant issues affecting sales.

"Outstanding operator comfort is a key to high productivity because it allows the operator to work longer hours," says Jim Hughes, Case brand marketing manager for skid-steer loaders. "Operator comfort results from a combination of features. Flip-back controls provide easy entry and exit. Side-mounted instrumentation and accessory switches are within easy reach without obstructing the operator's view to the work area. Low-effort servo hydrostatic controls help reduce operator fatigue and increase controllability to make novice operators good and good operators better.

Bobcat has added control features, such as speed control, to reduce operator stress. Selectable Joystick Controls allow the operator to dial in a desired ground speed, which the machine will maintain with minimal control effort. For example, an operator using a planer attachment for long shifts can simply select the ground speed that suits the attachment and milling conditions, and the machine will run at that speed whenever he pushes the joysticks forward. The operator does not have to feather the controls to hold the machine at a desired speed.

Pilot-operated hydraulic controls — joysticks that trade mechanical linkages for low-pressure pilot hydraulic systems as their means of moving valve spools that are under system pressure — are becoming quite common even on mid-sized skid-steers. When asked about the one technology most affecting sales of 1,600- to 2,200-pound machines, Volvo's Bill Sauber says, "all-hydraulic pilot controls for smooth, low effort steering and loader hydraulic function."

Kelly Moore, product manager for skid-steer loaders at Gehl, says hands-only controls with his company's T handle drive lever are a significant advantage. Like many skid-steer lines, Gehl machines have various alternate control choices, and Moore says Gehl's mid-sized models will offer twin joystick controls soon.

"But the original hands-style control system with our T handle on the left that functions as the drive control is the most prevalent choice," Moore says.

Komatsu offers three control patterns, ranging from traditional hand and foot controls to two variations of the increasingly popular all-hand controls. All three control patterns use Komatsu's Proportional Pressure Control (PPC) joysticks and are fully hydraulic.

Caterpillar's Kent Pellegrini amplifies the benefits of refined pilot-hydraulic controls.

"By providing [pilot-hydraulic] joysticks on our skid-steer loader, we can improve material handling capability and in turn provide profits back to the customer," says Pellegrini, skid-steer and multi-terrain-loader industry manager at Cat. "Controlling the load through the joysticks when handling expensive paving stones, slate stone or trees has a very smooth load-placing affect. Having the ability to feather the joystick controls to place the load will reduce the amount of broken hardscaping materials. The end result saves you the cost of expensive broken stone."

Hydraulic performance enhancements sometimes accompany new skid-steer loaders because, as Bob Beesley, product manager for skid-steers at Komatsu points out when asked about recent, crucial technologies, "the introduction of new attachments is allowing ever more applications [of skid-steers]. This can be measured by the increased number of 'package deals' and the sale of attachments."

Twenty-three out of the industry's 32 mid-range skid-steer models are available with optional high-flow hydraulic pumps. Eighteen of those high-flow pumps boost flow by 50 percent or more over standard flow rates. This optional upgrade makes the machine a more aggressive loader, but its primary purpose is to drive hydromechanical attachments such as breakers, brooms and cold planers.

Standard pumps on most of the mid-range machines develop theoretical hydraulic horsepower (calculated by multiplying flow times relief pressure and dividing by the constant, 1714) between 30 and 40. But the fact that there are some standard machines at 23 or 24 hydraulic horsepower and some as high as 43 hydraulic horsepower is strong evidence of the diversity of customer expectations. In fact Caterpillar, for instance, fields the 232B at 28 hydraulic horsepower, the 236B and 246B at nearly 43 hydraulic horsepower, and the 248B at more than 78 hydraulic horsepower.

With such a range of hydraulic performance from which to choose, and differences in designs of loader arms and wheelbases, there's likely to be a mid-sized skid-steer matched to almost any job. Buyers will have to consider their needs, and then go out and try a lot of machines to make sure they align the perfect combination of capabilities, features and cost.

Average Skid-Steer-Loader Costs
Rated Operating Cap. (lb.) List Price Hourly Rate*
* Monthly ownership cost (based on list price and 5.125 percent interest) plus operating expenses (including fuel at $2.49 per gallon and $40.18 per hour for mechanic's wages) divided by 176 hours.
Source: www.EquipmentWatch.com, 800-669-3282
1,601 to 1,750 $27,297 $22.82
1,751 to 2,200 $31,090 $25.30

Mid-Range Skid-Steer Specifications
Model Standard ROC* (lb.) Bucket Dig Force (lb.ft.) HP Standard** Flow (gpm) Oper. Wt. (lb.)
* Rated operating capacity ** Optional high-flow version available Source: www.spec-check.com
Twenty-two of the models in this size range are available with optional high-flow hydraulic pumps. Hydraulic horsepower with standard pumps runs the gamut from 23 to 43 horsepower, and high-flow options take the maximum up over 78 hydraulic horsepower. 
Bobcat S160 1,600 56 16.9** 6,115
New Holland L160 1,600 3,712 44 15.5 5,534
Gehl 4640E Turbo 1,650 60 19** 6,200
Mustang 2054 1,650 5,000 47 18.5** 6,050
Bobcat S175 1,750 46 16.9** 6,220
Case 420 1,750 4,129 56 18** 5,813
Caterpillar 232B 1,750 4,059 49 15.6 6,661
Caterpillar 236B 1,750 5,484 70 22 7,007
John Deere 317 1,750 5,500 57 17** 6,300
Komatsu SK818-5 1,750 3,530 47 16.1** 6,402
Thomas 175 1,750 4,250 56 16.6 7,000
New Holland L170 1,765 3,712 50 17.7** 5,540
Bobcat S185 1,850 56 16.9** 6,220
Volvo MC80B 1,850 7,532 65.2 20.3 6,824
Gehl 4840E 1,900 60 19** 6,480
Komatsu SK820-5 1,900 3,530 54 16** 6,480
John Deere 320 1,950 5,500 62 19** 6,435
JCB 190 1,985 4,387 70 20** 7,717
Case 430 2,000 5,413 74 21** 6,875
Caterpillar 242B 2,000 4,059 57 15.6** 6,802
Caterpillar 246B 2,000 5,484 78 22 7,142
Caterpillar 248B 2,000 5,484 76 33 7,321
Komatsu SK1020-5 2,000 5,038 70 21** 7,573
Mustang 2066 2,000 5,820 60 21.5 7,480
Volvo MC90B 2,000 7,531 80.5 20.3** 6,985
Bobcat S205 2,050 61 16.3** 6,655
Thomas 205 2,100 4,850 56 20 7,200
Bobcat S220 2,200 75 20.7** 7,483
Case 440 2,200 6,198 82 21 6,980
Gehl 5640E Turbo 2,200 82 23** 7,380
Mustang 2076 2,200 5,820 80 21.5** 7,480
New Holland L180 2,200 6,034 59 19.3** 7,095


Web Resources
  Bobcat www.bobcat.com
Case www.casece.com Caterpillar www.cat.com
Gehl www.gehl.com JCB www.jcb.com
John Deere www.deere.com Komatsu www.komatsuamerica.com
Mustang www.mustangmfg.com New Holland www.newhollandconstruction.com
Thomas www.thomasloaders.com Volvo www.volvoce.com

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