Hale MG - Manual (Page 19)

Muscle Pumps
1-12
D. Pump Drives
Pump Mounting Options
There are four common types of centrifugal pump
drives used with fire fighting apparatus:
q Operation from the truck chassis drive
shaft (split-shaft gearbox).
q Operation from a separate engine.
q Operation from the front of the truck
chassis engine (front engine PTO)
crankshaft.
q Operation from a PTO from the truck
transmission, a PTO before the engine
drive transmission or a PTO from the
four-wheel drive transfer case.
G-Series Gearbox
The most common pump drive is the split-shaft
gearbox.
The Hale G-Series split-shaft gearbox is available
as a short (S), long (L), or extra long (X) model.
The model designation S, L, or X, provides for
different distances from the pump centerline/mount
location to the center of the drive shaft for proper
drive line angles. The location, pump and drive
line angle determine the optimum gearbox length
selection.
Hale offers a variety of pump gear ratios to accom-
modate a wide range of apparatus manufacturer
requirements based on engine speed and available
horsepower. The gearbox (figure 1-12) consists
of the gearbox, gear set, and input and shafts
thatare both made of heat-treated nickel steel. This
unit can withstand the full torque of the engine in
road operating conditions up to 16,000 pounds-feet
(21,693 N-m).
Principle of Operation
Midship pumps are so named because of their
location on the fire apparatus. They are nor mally
driven through an integral transmission that has a
sliding gear shaft and sliding gear that selectively
directs the engine power to the pump or the rear axle.
Figure 1-13 shows the typical midship pump split-
shaft arrangement on a typical chassis.
The midship transmission is capable of handling
full engine horsepower, enabling the pump to meet
optimum performance levels as well as all torque
requirements for over the road applications.
LP and XP Gearbox
In addition to the standard Hale gearboxes there is
also available a “P” series gearbox. The “P” series
gearbox contains a third stage “power take-off”
that permits the mounting of an air compressor or
other auxiliary drive component.
Shifting
If the gearbox is equipped with a power shift
system, an in-cab control valve is provided for
mode selection. This control locks in place for
pump operation. Indicator lights are provided to
alert the operator when the gearbox has fully
shifted from road to pump position. Additionally,
provision is provided for manual shift due to
failure of the power shift system.