Sandvik Mining Tamrock HELAC EPrint

8/10/2019 Sandvik Mining Tamrock HELAC EPrint

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A P e n t o n Pu b l i c a t i o n

In this issueIn this issue

Hard Rock

Hydraulicsplays

Walking on air

Stop leaks in

their tracks

Spotlight on seals

www.hyd rau l i c spneumat i cs . com



RotaryactuatorsRotaryactuators

Components serve as rotating device,mounting bracket, and bearing support inhard rock drilling machine

do triple duty

INDUSTRY FOCUS: MINING By Richard T. Schneider

Contributing Editor

Tamrock Axera 226 —

known in its industry as a

Jumbo — has a 4-wheel

drive, center-articulated

carrier that makes it

highly maneuverable

in confined spaces.

Large tires and high

ground clearance enable

operation on uneven and

wet surfaces.

Courtesy, Sandvik Tamrock Secoma SAS

The Tamrock Axera 226 — built inLyon, France, by Sandvik Mining andConstruction — is a rubber-tired, twin-

boom rock-drilling machine. Typically usedfor underground hard-rock mining and tun-neling applications, the machine is designedto drill a series of holes in the face, sides,roof, and floor of a chamber without beingmoved. It can produce cross-sectional areasbetween 6- and 40 m2 from one position.Depending on the application, rock bolts orexplosives are inserted into the holes. Withthe drills located at the outboard ends ofthe booms, the risk of injury to the operatorand damage to the main machine from fall-ing rock and debris is minimized during thedrilling operation.

Power comes from a Deutz BF4M2012diesel engine that delivers 74 kW (100 hp).The rig carries twin 55-kW hydraulic powerunits that produce 18 to 24 kW of percussivepower. A drill mechanism uses a combina-tion of percussion and rotation of the drillbit. A manually operated, hydraulically con-trolled drilling system — with multiple auto-matic functions — allows high drilling per-formance with good drill-steel economy andhigh reliability.

The dual-boom design extends the timeperiod between drill-bit changes. In addi-tion, one boom can work while the otheris being set up. A series of rugged cylinderscoordinates the X-Y boom movements andmanipulates the feed, making control of thedrill simple and logical. Each boom includesa 360° helical rotary actuator that helical ro-tary actuator that enables the operator to rollthe feed beam over to drill into face, side,roof, and floor surfaces. The actuator alsocan position the feed for full visibility overthe top of the feed and the drill bit.

Helac Corp., Enumclaw, Wash., manu-factures the Model L30-95-S-RL-360-L1-C-Hhelical rotary actuators.



radial, moment, and thrust loads without the need for addi tional, ex-ternal bearings.

In the Axera 226 machine, one ac-tuator supports the entire drill headassembly on each boom. Becauseall sealing occurs against smooth,

cylindrical surfaces, internal by-pass and external leakage has effec-tively been eliminated, resulting insmooth positioning capabilities andzero drift after a position has beenselected. The actuator has an integraldual counterbalance valve that fur-ther improves positioning accuracyand adds an extra margin of safety incase of system failure. In short, thehelical rotary actuator functions asrotating device, mounting bracket,and bearing support — all in onecomponent.

F o r m o r e i n f o r ma t i o n o n ro -tary helical actuators, call (360)825-1601 or visit www.helac.com.

INDUSTRY FOCUS: MINING

The rotary actuators are integralparts of the machine, mounted in-linebetween the booms and drill heads.Their large, circular, integral shaftflange — with drilled and tapped boltcircle — is used to attach the actuatorto the boom.

The drill head assembly is attached

to the actuator’s octagonal rearmounting flange. The actuator’s shaftremains stationary with the boom

while the housing and drill head ro-tate. (The actuator also incorporatesa drilled and tapped mounting railon the housing. Sandvik uses the rai lmounting style for other rotating ap-plications.)

Helac Corp., Enumclaw, Wash.,manufactures the Model L30-95-S-RL-360-L1-C-H helical rotary actuators.The rotary actuators are integral partsof the machine, mounted in-line be-tween the booms and drill heads. Theirlarge, circular, integral shaft flange —

with drilled and tapped bolt circle —is used to attach the actuator to theboom.

The drill head assembly is attachedto the actuator’s octagonal rearmounting flange. The actuator’s shaftremains stationary with the boom while the housing and drill head ro-

tate. (The actuator also incorporatesa drilled and tapped mounting railon the housing. Sandvik uses the railmounting style for other rotating ap-plications.)

The unique characteristics of the he-

lical rotary actuator make it ideal forthis application. Its sliding-spline oper-ating concept (see boxed description)produces very high output torque (inthis case: 90,000 lb-in. at 3000 psi) froma compact configuration. The actuatormeasures 33 in. in overall length withan 8-in. housing diameter. It weighs415 lb.

Because all spline teeth remain en-gaged at all times, loads are equallydistributed over the teeth This resultsin exceptional durability and high tol-erance to the shock loads inherent inrock drilling. Backlash is almost neg-ligible — approximately 1°. Helac’spatented integral bearing design en-ables the actuator to support heavy

Twin booms, with drill heads on outboardends, improve production.

Model L30-95-S-RL-360-L1-C-H rotary

actuator has drilled and tapped mountingrail on the housing. Sandvik uses therail mounting style for other rotatingapplications.

Model B 26 F OF boom on Axera 226 combines series of cylinders and helical rotaryactuator for accurate positioning of drill head.

Slave feed-swingcylinder

Boom-swingcylinder

Boom-extensioncylinder

Boom-liftcylinder

Mainfeed-swingcylinder

Divergence

cylinder

Feed-extensioncylinder

Feed-tilt cylinder

Feed-rollover

actuator

Helical actuators are composed of a housing and only two moving parts: a centralthrough shaft and an annular piston. As hydraulic pressure is applied, the pistonis displaced axially, while the helical gearing on the piston OD and housing’s ringgear cause the simultaneous rotation of the piston. At the same time, gearing onthe piston ID and shaft causes the shaft to rotate.

Copyright © 2010 by Penton Media, Inc.

Sandvik Mining Tamrock HELAC EPrint

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