Pipelayer / Dozer Attachment
Combo Unit
One machine, two jobs. The Vanguard Combo Unit adds a folding-boom pipelayer to a Caterpillar D5N or D6N LGP track-type tractor while retaining the VPAT dozer blade.
Base machines: Caterpillar D5N LGP and D6N LGP track-type tractors
Overview
The Vanguard pipelayer system includes winches, boom, mode control, lockout cylinders and attachment frames. The pipelayer support structure mounts directly to the tractor main frame, which allows the tracks to oscillate in dozing mode, and the structure is easily removed.
A single Mode Control lever offers quick selection of machine operating function — pipelayer or dozer. Hydraulically actuated lockout cylinders automatically deploy in pipelaying mode to lock the equalizer bar and provide a stable lifting platform, then retract automatically in dozing mode.
Winch and boom
- Boom and hook drawworks are driven by independent hydraulic winches.
- Oil-disc brakes provide smooth operation and positive retention of boom and hook positions.
- Modular design allows fast replacement, easy field service and testing.
- Infinitely variable speed controls for both boom and hook allow precise control.
- Tubular, cast-steel boom is rugged and delivers better fatigue life; replaceable boom-mount bearings.
- Emergency quick-drop function on load-line control allows the operator to drop the load quickly.
Lockout cylinder and folding boom
Lockout cylinder
The VEI pipelayer locks out the tractor's equalizer bar with hydraulically actuated cylinders. These deploy automatically in pipelaying mode and retract automatically in dozing mode as controlled through the Mode Control lever. When deployed they contact the equalizer bar, preventing any upward movement and providing a stable lifting platform.
Folding boom configuration
Offers fast, easy boom storage using only the winch controls and requiring only the operator.
Pipelayer support structure
Mounts directly to the main frame, which allows the tracks to oscillate. The structure is easily removed. Its design allows clear vision lines to the blade corners when dozing, with the blade straight or angled.
Operator's station
Ergonomically designed for maximum comfort, vision and productivity. Pipelayer controls are low effort and allow simultaneous, precise positioning of load line and boom: 1 hook control, 2 boom control, 3 safety lockout, 4 mode control.
Work tools: VPAT blade
Variable Pitch Power Angle and Tilt (VPAT) blade with manually adjustable pitch for optimum performance.
- Blade pitch is changed easily by adjusting four bolts and shims; full hydraulic control of lift, dig, angle and tilt.
- C-frame is solidly pinned to the main frame for good blade control and elimination of blade motion due to track oscillation.
- Lubrication points at all pin joints; C-frame-to-tractor joint sealed and lubricated with remote lube.
- Angle-cylinder bypass valve and line guards reduce stress and protect lines from sharp objects and abrasive materials.
- 54° position gives maximum blade loads and the most aggressive dozing (production dozing, carry, backfill, land clearing). 57.5° and 60° are intermediate positions for general dozing. 62° leaves an unrutted surface for finish grading.
Standard and optional equipment
Standard
Load winch with quick-drop; boom winch; separate hydraulic pilot-operated controls for load, boom and mode selection; folding boom; two- or three-part load line including blocks; two-part boom line including block; two hydraulic cylinder lockouts for automatic hardbar locking/unlocking.
Optional
6.1 m (20 ft) straight, square-section rigid boom (approx. −90.7 kg / −200 lb); bending-shoe adapter bracket (+45.4 kg / +100 lb); modification kit for EROPS installation (+22.7 kg / +50 lb; winches not to be used in conjunction with EROPS).
Specifications
Hydraulic power
| Tractor | Flow | Pressure | Pump speed |
|---|---|---|---|
| D5N | 25 gpm | 3,000 psi | 2,200 rpm |
| D6N | 35 gpm | 3,250 psi | 2,200 rpm |
Planetary hydraulic winches (D5N / D6N)
| Item | Hook winch | Boom winch |
|---|---|---|
| Drum diameter | 193 mm / 7.6 in | 178 mm / 7 in |
| Flange diameter | 279 mm / 11 in | 203 mm / 8 in |
| Drum length | 371 mm / 14.6 in | 254 mm / 10 in |
| Capacity, 16 mm (5/8 in) rope: D5N / D6N | 35.7 m (117 ft) / 67.7 m (222 ft) | |
| Wire rope installed, 16 mm (5/8 in): D5N / D6N | 22.6 m (74 ft) / 39.2 m (121.6 ft) | |
| Wire rope installed, 13 mm (1/2 in): D5N / D6N | 19.4 m (63.6 ft) / 32.9 m (106 ft) | |
| Bare-drum line speed, no load | 22.6–32.3 m/min (74–106 ft/min) | 30–43.6 m/min (98–143 ft/min) |
| Two-part line hook speed | 11.3 m/min / 37 ft/min | |
| Three-part line hook speed | 10.8 m/min / 35.3 ft/min | |
| Boom length | 5.56 m (18 ft 2¾ in) folding; 6.1 m (20 ft) optional rigid |
Tractor and pipelayer dimensions (LGP with pipelayer attachment)
| Dimension | D5N Combo | D6N Combo |
|---|---|---|
| Track gauge | 2 000 mm / 79 in | 2 160 mm / 85 in |
| Width of tractor, boom and blade removed | 3 143 mm / 123.75 in | 3 409 mm / 134.2 in |
| Width of tractor, folding boom folded, blade removed | 3 327 mm / 131 in | 3 614 mm / 142.3 in |
| Machine height from tip of grouser, ROPS canopy | 3 036 mm / 119.5 in | 3 136 mm / 123 in |
| Machine height from tip of grouser, ROPS cab | 3 039 mm / 119.6 in | 3 197 mm / 126 in |
| Folding boom extended vertically | 6 746 mm / 265.6 in | 6 850 mm / 269.7 in |
| Drawbar height (center of clevis) from ground face of shoe | 537 mm / 21 in | 710 mm / 27.9 in |
| Length of track on ground | 2 604 mm / 103 in | 3 102 mm / 122 in |
| Length of basic tractor with drawbar | 3 720 mm / 146 in | 4 149 mm / 163 in |
| Height over stack from tip of grouser | 2 849 mm / 112 in | 3 000 mm / 118 in |
| Grouser height | 47 mm / 1.85 in | 57 mm / 2.2 in |
| Ground clearance (SAE J1234) | 422 mm / 16.6 in | 538 mm / 21.2 in |
Refer to the brochure for the complete dimension table, including folded-boom heights and blade-added lengths.
Bulldozer specifications
| Item | D5N LGP — 5 VPAT blade | D6N LGP — 6 VPAT blade |
|---|---|---|
| Blade capacity (SAE J1265) | 2.6 m³ / 3.4 yd³ | 3.16 m³ / 4.13 yd³ |
| Blade width over end bits | 3 360 mm / 132 in | 4 080 mm / 160.6 in |
| Total operating weight with blade and pipelayer attachment, incl. 18 ft folding boom (power shift FTC) | 16 565 kg / 36,520 lb | 22 675 kg / 49,990 lb |
| Total operating weight, power shift DS | — | 23 481 kg / 51,940 lb |
A special-use 5PLGP blade is available for applications with a 3,000 mm (118 in) transportation width restriction. Optional pipelayer width available on special order.
Lifting capacity configuration (20 ft / 6.1 m maximum boom)
| Item | D5N LGP attachment | D6N LGP attachment |
|---|---|---|
| Load line | 5/8 in (16 mm) wire rope, 41,200 lb (18,700 kg) min. breaking strength | 5/8 in (16 mm) wire rope, 41,200 lb (18,700 kg) min. breaking strength |
| Boom line | 1/2 in (13 mm) wire rope, 26,600 lb (12,070 kg) min. breaking strength | 1/2 in (13 mm) wire rope, 26,600 lb (12,070 kg) min. breaking strength |
| Parts of line | 3-part load line, 3-part boom line | 2-part load line, 2-part boom line |
| Counterweight | None additional with 5 VPAT blade installed | None additional with 6 VPAT blade installed |
| Track shoe width | Reduced to 24 in | Reduced to 24 in |
See the load charts in the brochure for rated capacity versus load overhang.
Materials and specifications are subject to change without notice. Refer to the brochure and Operator & Maintenance Manual for complete data.
Photos
Downloads
Combo Unit brochure (8 pages)Product brochurePDF
Operator & Maintenance Manuals
Pipelayer Attachment / Combo033-08OP-003C · D5H LGP, D6M LGP, D6N LGPPDF
Pipelayer Attachment / Combo032-08OP-007D · D4H LGP, D5M LGP, D5N LGPPDF
VEI Combination Pipelayers — Machine Operation Overview032-08OP-SUM-01APDF
71H Pipelayer043-08OP-002B-01 · D6N LGPPDF
71H II — EPH Pipelayer043-08OP-004A · D6N LGPPDF
71N Pipelayer043-08OP-001B · D6N LGPPDF
Made under license from Caterpillar, Inc. Cat and Caterpillar are registered trademarks of Caterpillar, Inc. All marks are used with permission of Caterpillar.