2005 VOL. 24 NO. 1

Hydraulics and hydrostatic technol-ogy have made a rapid entry into

the world of crawler dozers. Just a few years ago, powershift dozers were the norm. But now more and more hydrostatic dozers are coming into the market, and with them come new challenges for the towing winch.

The key challenge is the PTO shaft, or more correctly the lack of one. Where the PTO shaft was once standard on almost every dozer, many of the new generation machines have no PTO shaft. The classic powershift towing winch, developed at Hyster and con-tinued at Allied, is no longer an option for this type of dozer.

The power take-off is still the simplest and most cost-effective way to drive a winch. However, if the PTO is not avail-able, the solution is a hydraulic winch. But it’s a bit more complicated than just strapping an existing hydraulic winch to the back of a dozer and con-necting a hydraulic oil supply. Some

ROUTE TO:Sales ManagerParts ManagerService Manager

hydraulic winches aren’t designed for dozer applications. And sometimes the hydraulic system can’t provide suffi cient power. The best choice is engineering a winch specifi cally for a dozer, not simply adapting a fi shing boat winch or crane winch to a dozer.

The fi rst engineering decision is hy-draulic supply. The dozer’s auxiliary pump, which often operates the rip-per, is usually adequate for self-rescue or for occasional use. For production applications such as logging, a higher-fl ow hydraulic pump is required.

The second key design point is side loading. A dozer winch is frequently subject to side pulls, and the drum

bearings and winch housing must be strong enough to handle this rough usage. Some hydraulic winches not originally designed for a dozer, such as a fi shing boat winch or crane winch, try to compensate for side loading by dictating the use of a fairlead with the winch. Allied hydraulic winches are designed as true dozer winches, with-out the requirement for a fairlead. Of course, the fairlead remains an option to help reduce wear on the wire rope and abrasion on the winch case.

Finally, the winch needs to have a slanted rear profi le so that it doesn’t strike the ground when climbing steep hills. This issue is typically not con-sidered in developing a fi shing boat

(Continued on next page)

Hydraulics to the Rescue

Allied H4A Hydrostatic WinchStandard Gear Ratio

Line pull, bare drumLine pull, full drum

31,900 lbs18,300 lbs

Line speed, bare drumLine speed, full drum

119 ft/min207 ft/min

Cable capacity@ wire rope dia.

277 ft5/8 inch

Weight 1,350 lbs

Available for:• Caterpillar D3/4/5G• Komatsu D31/37/39 KomStat• John Deere 450J–650J, 700J

The Allied H4A winch addresses the winch requirements of the new generation of small hydrostatic dozers. It is designed specifi cally for dozer applications, incorporating key features that add maximum value to the users.

The Allied H4A winch addresses the winch requirements of the new generation of small

A newsletter published by

Allied Systems Company Winch Division

2300 Oregon StreetSherwood, OR 97140-9799 U.S.A.Telephone: 503.625.2560Fax: 503.625.7269www.alliedsystems.com

“Hydraulics to the Rescue”(Continued from previous page)

winch, but is important for dozer ap-plications.

The Allied H4A winch is our fi rst hydrostatic towing winch for the new generation of hydrostatic dozers. With a line pull rating of 40,000 lbs peak line pull, it is the ideal choice for a

The Cat D3G outfi tted with the Allied H4A winch is an ideal package for logging and site preparation applications in North America. Allied supplies the winch pump, which connects to the back of the main drive pumps.

A perverse aspect of new technology is that it often complicates life,

especially for ongoing maintenance. Fortunately, this is not the case with a hydraulic winch. In fact, there is al-most no ongoing service needed. The only signifi cant requirement is main-taining the cleanliness of the hydraulic oil.

Some of our winches have an inde-pendent hydraulic system, such as the H4A winch on Caterpillar G Series. This winch has its own hydraulic oil

Hydraulic Winches Simple to Maintain

reservoir and fi lter. It is imperative to respect the replacement schedule for both fl uid and fi lter on this winch. While the traditional PTO winch could run for years on the original oil (though not recommended), this prac-tice won’t work on the H4A winch.

By contrast, some of our other hy-draulic winches connect to the dozer auxiliary hydraulic circuit. Here, the oil change frequency is dictated by the dozer manufacturer. But it also must be respected faithfully.

wide variety of smaller dozers. It has a 2-speed motor that senses the load requirements, to permit high line pull when heavily loaded and fast line speed when lightly loaded. Control is through a single-lever pilot control, which requires only fi ngertip pressure to operate, and which delivers precise

speed control.

One of the great advantages of a hydraulic winch is exceptional control over line speed and line position. This opens up new opportunities such as power line sagging, pulling pipe for re-lining old pipelines and sewer systems, pulling cable through under-ground conduits, and other work that requires precise control of large loads.

This winch has unusual versatility, which allows it to be used on many different tractor models. Hydraulic supply can come from a dedicated pump, for maximum performance, or it can come from the dozer auxiliary system, for occasional self-rescue.

Standard features include power in, power out, and freespool. Options include 4-roller fairlead, integral log arch, and bolt-on drawbar. A slow-speed gear ratio is available where greater peak line pull is required.

The winch comes with everything re-quired for a complete and professional installation, and it’s easy to install in the fi eld. This allows the dealership to mount a winch on a tractor from stock that is not made winch-ready at the factory.

The Cat D3G outfi tted with the Allied H4A winch is an ideal package for logging and site preparation