Atlas Copco Hydraulic boomsBUT 28

A heavy duty hydraulic boom with ability to handlepowerful hydraulic rock drills.

Main features� With the direct positioning system, the boom can be moved

straight to the next collaring location.� Double tripod suspension gives accurate parallel holding in all

directions.� 360 degrees feed roll-over gives full coverage of the tunnel face

without any blind spots and with no change in parallelity.� Feed tilt cylinder rotates the feed into vertical position with the

rock drill facing the operator. This gives fast and simple roofdrilling and good supervision of the drilling sequence.

� Main boom joints have axial bearings and bushings, and boomjoints for the cylinders are fitted with adjustable expanding shaftsall maintaining the accuracy and operational precision of theboom.

� BUT 28 booms are compact and capable of carrying powerfulhydraulic rock drills.

BUT 28 is a heavy duty hydraulicboom with unique features forefficient and trouble-free opera-tion. BUT 28 has a coverage areaof 48 m2. It is intended for usein mining and tunnelling, anddesigned for operation withinmedium-size drifts and under-ground openings. The excellentstability and accuracy of move-ment give fast positioning, lowdrill steel costs and straightholes.

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BUT 28DataWeight, boom only 1750 kgFeed extension 1250 mmBoom extension 1250 mmFeed roll-over 360 degreesCoverage area 48 m2

Hydraulic system pressure 170-210 barMax. weight of feed androck drill to be mounted 700 kgBoom mounting plate, w x h 480 x 690 mm

The BUT 28 booms can be used together with thefollowing equipment:

Rock drills: COP 1838, COP 1432, COP 1238Feeds: BMH 2000, BMHT 2600, BMHE 2000,BMHS 2000

7321

4443

8571

Coverage area with parallel holes

50o 90o

30o

21001250

1250

2700

5476

Centre of gravity

781

27o

360o

R58

2

45o

45o

45o

45o

500

Scale 1:150

Accurate parallel holdingThe boom has hydraulic parallelholding of the feed due to a uniquedouble tripod suspension system,which provides precise parallelholding during all movements ofthe boom, resulting in improvedblasting effect and longer ad-vances per round.The parallel holding will also helpto maintain a proper lock-out onperimeter holes, therefore reduc-ing the risk of overbreak orunderbreak.

Easy and logical operationThe shortest way is the fastest. Lift and swing movements of the boomand feed are all controlled with only one joystick lever, which providesswift movements of the boom from one hole straight to the next. Thespeed at which the boom moves is propotional to the movement of thelever. This means that the boom can be moved smoothly and preciselywhen needed.A colour coding system is used, where each cylinder and its control leverare marked with a specific colour. This simplifies learning and makes iteasier to select the correct lever.

Expanding shaftsBoom joints for the cylinders arefitted with adjustable expandingshafts. Boom accuracy and opera-tional precision can be maintainedthroughout the entire service life ofthe equipment, simply by tighten-ing a nut.

StabilityThe robust and stable structure ofBUT 28 allows the feed to befirmly braced against the face witha force of up to 17.5 kN. Thisprovides for stable and straightcollaring of the hole, a prerequisitefor correct hole alignment.

BUT 28 � direct positioning boom with accurate, fast andsimple manoeuvering.

New main boom jointsThe main boom ends are providedwith new type of joints with fixedshafts, axial bearings and bushings.The joints are prepared for installa-tion of sensors to monitor themovements of the boom.

Boom control systemThe boom is prepared for instal-lation of angle reading sensorsand length meusuring sensorsfor monitoring of the boom andfeed position. The information isdisplayed on a colour monitor onthe rig.

Options

Boom lubrication systemThe rear part of the boom can beequipped with an automaticlubrication system which servesa number of lubpoints.Main boom joint

Feed tilt cylinder 90o

Feed extension cylinder

Feed rotation 360o

Feed extension 1250 mm

Boom extension 1250 mm

Automatic boomlubrication (option)

1 2 3 4

98

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6

75

Featuring rapid and exact boom positioning with easy and logical joystickmanoeuvring, the Atlas Copco Boomer rigs equipped with BUT 28booms give you optimum effective drilling. Roof-drilling and crosscuts areas easy as face drifting.

Pressure and return hosesfor rock drill precussion areseparated

Hydraulic hosesThe boom has standard hoselengths with bulkhead at the rearboom end that facilitate mainte-nance (fewer hose lengths to bekept in stock). Pressure and returnhoses for rock drill percussion areseparated to reduce wear andfacilitate maintenance (easier andfaster to change hoses).

VersatilityThe BUT 28 boom can align andposition the feed to meet alldrilling angles and drilling patterns.With a rotation angle of 360º, thefeed can be rolled to position therock drill extremely close to thetunnel wall for drilling of contourholes. Look-out angles are setwith the tilt cylinder and the feedreturned to parallel alignment withthe control lever. This enablesprecision drilling of contour holeswith a minimum of overbreak.For roof drilling the feed is directlyswung into vertical position usingthe tilt cylinder. This then orientsthe rockdrill towards the operator,

Coverage areaThe boom features the horse-shoetype of coverage area withoutblind spots, easily adaptable to thetunnel profile.

simplifying positioning and super-vision of the drilling sequence.With 90º feed tilt and 90º feedrotation, the feed can be posi-tioned for cross-cut drilling. Holepositioning occurs through raisingor lowering the boom, and withthe boom and feed extension.

Bulkhead

Adjustable wear plateson feed holder

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2

5

1

4

3

78

6

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Sensors function for boom control system1. Sensors for boom swing angle2. Sensors for boom lift angle3. Sensor for feed rotation angle4. Sensor for feed tilt angle5. Sensor for boom extension6. Sensor for feed extension7. Sensor for hole depth8. Gravimeter

1. Cover, 2. Locking pin, 3. Axialbearing, 4. Bushing, 5. Shaft

Optional angle reading sensor6. Senor, 7. Flexible shaft,8. Quick joint, 9. Adapter

Double tripod suspension givesaccurate parallel holding in alldirections.