Products & Equipment Pits & Quarries
Martin introduces new Impact Cradles

April 2, 2015 – Martin Engineering’s new line of Impact
Cradles Heavy Duty (HD), Medium Duty (MD) and Light Duty (LD) feature a bed of
steel angles lined by energy-absorbing impact bars with a top layer of low
friction, ultra-high molecular weight (UHMW) plastic. The result is longer
lasting conveyor belts and components, with less fugitive material and a safer
work area.

April 2, 2015 – Martin Engineering’s new line of Impact
Cradles Heavy Duty (HD), Medium Duty (MD) and Light Duty (LD) feature a bed of
steel angles lined by energy-absorbing impact bars with a top layer of low
friction, ultra-high molecular weight (UHMW) plastic. The result is longer
lasting conveyor belts and components, with less fugitive material and a safer
work area.

The Martin Engineering cradles are designed to be located at
transfer points of receiving conveyors, under the hopper and chute box, close
to the tail pulley.  Depending on the
force of the discharged material, they can possess different structural
qualities. All three Martin Impact Cradles feature wing supports, which adjust
to match CEMA standard trough angles, as well as a five per cent fine-tuning
adjustment angle. This allows for the cradle to accommodate the idler profiles
of different manufacturers and assure a tight belt seal.

The Martin Impact Cradle HD is the company’s most rugged
design, able to withstand impact forces from 12,000 to 17,000 lbf. (53.4 to
75.6 kN) and drop heights of light material up to 50 ft. (15.2 m). Classified
as Heavy-Duty (H) in CEMA Standard 575-2000, it fits E-6 and E-7 conveyor
configurations. Support beams in the center of the cradle are set 3/4" (19
mm) below the receiving belt’s line of travel, allowing the belt to avoid
sustained friction when running empty, yet absorbing significant impacts during
loading while still retaining a tight seal.

The unit is equipped with 7-13 heavy-duty impact bars,
depending on width.  Installed
perpendicular to the belt path, the bars are reinforced by a steel support
structure with a base of impact-absorbing 50-durometer styrene-butadiene (SBR)
rubber and a top layer of slick UHMW plastic. They are engineered to withstand
dynamic energy and a heat range of -29° to 60°C without compromising the
structural integrity of the conveyor frame. The cradle is on a Trac-Mount,
allowing it to slide out for easy bar replacement.

The Martin Impact Cradle MD is designed for medium duty
applications, suitable for use with belts traveling up to 1,000 ft./min. (5m/s).
Mounted on four rugged steel I-beam supports, the cradle is able to sustain a
maximum weight of 12,000 ft./lbs. (53.4 kN) with light material drop heights up
to 26 ft. (7.9m). Classified as Medium-Duty (M) in CEMA Standard 575-2000, the
unit is available for belt widths from 24" to 72" (500 to 1,828 mm).

Depending on width, the MD Cradle is fitted with six to 16
durable impact bars. They are composed of an aluminum T-slot surrounded by
energy absorbing 83A-durometer urethane, coated with a layer of low-friction
UHMW plastic, which prevents belt fraying while retaining a tight seal at
operating temperatures of -29° to 82°C. Each bar is reinforced by a bed of
steel “wing” supports, which can be adjusted to match any CEMA standard trough
angle, with five degrees of wear adjustment.

Like the MD, the Martin Impact Cradle LD conforms to CEMA
No. 502-1998 & 575-2000, but the Class L design is made for lighter
materials with impact forces that could still affect the belt and conveyor over
time. Utilizing the same impact bar technology, it is able to withstand a
maximum weight of 8,500 ft./lbs. (37.8 kN), equal to 50lbs. (22.7kg) being
dropped from 10 ft., with light material drop heights of up to 12 ft. (3.6m).

Mounted on three steel channel beams, the LD is available
for belts from 24-48 in. (610 to 1219mm) wide, with 6-10 impact bars. The unit
controls the spillage of dust and fines at belt speeds as high as 1,000 ft./min.
(5m/s).