Joy VCR280 Drifter

Established Performance in Deep Blast Hole Drilling
   
    The high performance Joy VCR-280 valveless continuous rotation drill is furnished as standard equipment on the Mustang track drill.  The VCR-280 drill produces optimum operating characteristics for independent rotation drilling and represents a radical departure from the design of other rock drills.  This is a hammer that gives you an honest capability for high speed drilling of 3-1/2" - 5-1/2" diameter blast holes deep into hard rock.

Fewer Moving Parts

    In place of impact and rotation through a maze of interconnected parts, the VCR-280 employs the piston as the only moving part in the hammer and a geared independent rotation unit that transmits high torque rotation to the drill steel and bit.  This is design simplicity that adds up to greater reliability for you.

Valveless Operation

    In the VCR-280 drill, valveless operation reduces the number of wearing parts -  the piston and porting in the cylinder act as the valve.  Because it is valveless, air consumption is significantly reduced.  The large bore, short stroke design produces 30% more blow per minute to use every cubic inch of air effectively.  The VCR-280 equipped Mustang track drill is built to run with complete effectiveness on only 1200 cfm of air at 100 psig.  And lower air requirements mean substantial savings on compressor costs.

Powerful Independent Rotation

    Independently powered rotation operated by and efficient gear-type air motor geared directly to the front head provides powerful torque for any drilling condition.  Massive, heavy-duty spur gears supported on anti-friction roller bearings are used throughout the assembly.  Rotating chuck parts are carried on large tapered roller bearings to substantially reduce thrust and radial drag.  Rate of rotation is infinitely variable to suit drilling conditions; instant reverse rotation speeds up drill steel changes.

Durable Construction

    Front end parts, rotation gearing, the percussion unit, and backhead are bolted together with four side rods (instead of the usual two) to form an integral unit with increased structural strength and permanent internal alignment of parts.

Quiet Operation

    The VCR-280 drill is equipped with a resiliently mounted, heavy-walled aluminum muffler that substantially reduces noise for increased operator comfort.  Efficiency of the muffler is enhanced by the inherent short stroke operating characteristics of the drill which lowers exhaust pressure and exhaust noise.  The VCR-280 is the only heavyweight drill presently offered with an integral muffler as standard equipment. 

How the VCR-280 Drill Engine Operates

    The two basic operating functions of the VCR-280 continuous rotation drill - percussion and rotation - are accomplished independent of each other.

Percussion

    Air entering the backhead passes directly into the cylinder cavity.  The piston reciprocated in the cylinder in a valveless cycle in which the piston itself functions as a valve, alternately exposing and covering air ports in the cylinder.  This is a volume expansion controlled cycle using only one moving part - the piston.

Rotation

    A separate air inlet admits air to a gear-type air motor.  The air motor transmits torque through the rotation gearing to the chuck driver which is splined to receive the striking bar.  Rotation (rpm) of the drill steel is continuously variable by use of the rotation valve on the drill, feed and valve control cluster.

VCR-280 Drill Specifications
Bore Diameter	8 in.  (20 cm)
Stroke	2-1/4 in.  (5.7 cm)
Chuck	Splined, Striking Bar
Rotation Type	Independent
Air Tube OD/ID	1-1/4 in. / 1-1/16 in.  (31.8 mm / 27.0 mm)
Air Hose ID, Drill	2-1/2 in.  (63.5 mm)
Air Hose ID, Blow	1-1/4 in.  (31.8 mm)
Air Hose ID, Rotation	1 in.  (25.4 mm)
Hole Size Range	4 in. - 5-1/2 in.  (102 mm - 140 mm)
Air Volume, Drill & Blow	1200 cfm  (34 m3/min.)
Air Volume, Drill Only	850 cfm  (24 m3/min.)
Air Pressure	100 psi  (7 kg/cm2)
Blows Per Minute	2000 bpm
Net Weight	790 lbs.  (358 kg)