Hoist And Wire Rope Installation - BRADEN BG4A Installation Maintenance And Service Manual

STATIC BRAKE
The static brake consists of three basic components.
1. Spring applied, multiple friction disk brake pack.
2. Solid brake coupling.
3. Hydraulic brake cylinder and spring plate.
The brake pack consists of alternatively stacked friction
and steel brake disks. The steel brake disks are externally
splined to the motor adapter and cannot rotate. The friction
disks are internally splined to the brake coupling. When
the hoist is not being operated, spring force compresses
the brake pack and locks the brake coupling to the motor
adapter, preventing the gear train or cable drum from ro-
tating in either direction. The solid brake coupling makes
the static brake "effective both directions". This means the
static brake must be released before the hoist can operate
in either the raise or lower direction.
The static brake is released by pilot pressure applied to the
brake cylinder. It releases at a pressure lower than that re-
quired to open the pilot operated counterbalance cartridge,
typically approx. 600 PSI (4,140 Kpa.) This sequence as-
sures that dynamic braking is done by the counterbalance
cartridge and that little, if any, heat is absorbed by the fric-
tion brake.
The static or friction brake is primarily a load holding brake
and will provide dynamic braking only during extremely slow
operation when there is insufficient flow and pressure to
open the counterbalance cartridge.
OPERATION
Since the static brake on this hoist is "effective both direc-
tions", the brake must be hydraulically released to operate
the hoist in either the hoist or lower direction.
When the hoist is powered in either direction, the motor can-
not rotate until sufficient pilot pressure is present to open the
counterbalance cartridge or check valve. The friction brake
will completely release at a pressure lower than required to
open the counterbalance cartridge during lowering. The ex-
tent to which the cartridge opens will determine the amount
of oil that can flow through it and the speed at which the
cable drum will turn. Increasing the flow of oil to the hoist
motor will cause the pressure to rise and the opening in the
cartridge to enlarge, speeding up the cable drum. Decreas-
ing the flow causes the pressure to drop and the opening in
the cartridge to decrease, slowing down the cable drum.
During raising operations, the check valve recieves a pilot
signal from the motor inlet port opening the check valve to
allow free flow of oil through the motor. When the control
valve is returned to the neutral or center position, pressure
will rapidly drop and the counterbalance cartridge will close,
stopping the load. The friction brake will engage and hold
the load after the cartridge is closed.
HOIST AND WIRE ROPE
INSTALLATION
1. The hoist should be mounted with the centerline of the
cable drum in a horizontal position. The mounting plane of
the hoist may be rotated in any position around this cen-
terline providing the vent in the motor adapter is above the
centerline of the cable drum. The vent should be as close to
top dead center as possible.
2. When mounting the hoist, use all four (4) mounting holes
and Grade 8 bolts and nuts. Evenly tighten the nuts to the
torque in the "Recommended Torque" chart. Refer to "Di-
mensional Drawing" for bolt hole size and pattern.
It is important that the hoist is mounted on a sur face that
will not flex when the hoist is in use, and cause binding of
the gear train. Binding in the gear train will result in accel-
erated wear and heat. Also, the mounting surface should
be flat with ± 0.020 inches. If necessary, install shims
under the hoist mounting pads to achieve even mounting.
3. The hydraulic lines and components that operate the hoist
should be of sufficient size to assure minimum back pres-
sure at the hoist. The back pressure at the motor must not
exceed 100 psi (690 kPa) to maintain full brake system de-
sign factor and optimum motor seal life.
The hoist directional control valve must be a three position
four way valve with a motor spool such that when the valve
is in the center position both work ports are open to tank
(open center, open port.)
4. High quality hydraulic oil is essential for satisfactory per-
formance and long hydraulic system component life. Oil hav-
ing 150 to 330 SUS viscosity at 100°F (38°C) and viscosity
index of 100 or greater will give good results under normal
temperature conditions. The use of an oil having a high
viscosity index will minimize cold start trouble and reduce
the length of warm-up periods. A high viscosity index will
minimize changes in viscosity with corresponding changes
in temperature.
Maximum cold weather start-up viscosity should not exceed
5,000 SUS with a pour point at least 20°F (11°C) lower than
the minimum ambient temperature.
Under continuous operating conditions the temperature of
the oil at any point in the system must not exceed 180ºF
(82°C). 120-140°F (49-60°C) is generally considered opti-
mum.
In general terms:
For continuous operation at ambient temperatures between
50 and 110°F (10-43°C) use ISO VG 46 – 68 (SAE20); for
continuous operation between 10 and 90°F (-12 and 32°C)
use ISO VG 32 (SAE10W); for applications colder than 10°F
(-12°C), contact the BRADEN Product Support Department.
The use of multi-viscosity oils is generally not recommend-
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