LeTourneau Tech's NOW, Volume 5, Number 11, June 1, 1951 Page: 3
This periodical is part of the collection entitled: LeTourneau University Archives and was provided to The Portal to Texas History by the LeTourneau University Margaret Estes Library.
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under the drag, more men will be to the pump-the troops, to complete
caught in the door and increase the the comparison, go through an air-
push until, when the door is stopped, conditioned room before going back
the push (or torque) will be at its through the revolving door.
maximum. j 7 tConsider the force of one man as
equal to the torque of the engine, the
marching of the men as the flow of the
oil under pressure, the revolving door
as the torque converter and you have,
in the simplest sense, the principle
of the torque converter. Just as the
revolving door under the constant
push of the troops will tend to speed
up as the drag is reduced, so a ma-
chine equipped with a torque conver-
ter will speed up as the drawbar pull
required is reduced. When the ma-
chine is stalled, and you need the
maxnmum possible pull, the torque
converter provides it-as the grade
levels off, or the scraper blade is
pulled out of the ground, torque or
the pulling requirements are reduced,
and the torque converter automat-
ically speeds up the machine. The
torque and the speed will always be
perfectly balanced so as to use the
maximum engine horsepower avail-
able, and the load will always move
at the fastest speed possible under the
given operating conditions.
WHAT CONSTITUTES A TOR-
QUE CONVERTER? A torque con-
verter has three main parts: First,
the IMPELLER which is connected
to the engine and acts as a pump to
put the oil under pressure-like the
line of marching troops, it provides
the "push;" second, the TURBINE
which is connected to the final drive,
and which is turned or pushed by the
oil under pressure, just as the revolv-
ing door is turned or pushed by the
troops; and finally, the REACTION
(STATIONARY) MEMBER that
diverts the oil back to the pump, so
that it may be used over and over
again-just as the troops could be
routed through a corridor to return
to the revolving door, so that they
could give it another push. The oil
gets warm in doing this work, and is
cooled by a radiator before going backSf-a
grade and ground conditions, and the
braking effort of the engine and the
Electrotarder will be in effect, just as
if a solid drive was being used.
MULTIPLE STAGE CONVERT-
ERS-The torque converter which
has been described is a single-stage
unit, consisting of one IMPELLER,
one TURBINE, and one REACTION
MEMBER-the oil has just one
chance to push on the turbine before
it returns to the pump. The single
stage torque converter is the type
which is currently being used in Le-
Tourneau products.
A two-stage converter has another
turbine, so the oil has two chances to
push. Picture again the revolving
door, and imagine the troops can be
in two compartments at the same
timeMany pieces of construction equip-
ment have engine driven attachments,
such as hydraulic pumps, generators,
etc. that operate most efficiently when
the speed of the engine is kept up to
its maximum. In LeTourneau pro-
ducts, it is highly desirable that the
generator is always run at or near
full speed, to provide maximum vol-
tage and best performance. The use
of a torque converter in such cases
will insure that the engine is always
at top speed, which means that the
unit and its attachments are always
working under the most favorable
conditions.
The output torque, the force which
actually moves the load, rises at about
the same rate as the speed of the unit
goes down. In other words, there is
more or less a constant amount of
horsepower going into the dr i v e
wheels on the machine whether the
unit is travelling at 30, 29, 28, 25, 22,
16 m.p.h., etc. Obviously, this is
impossible with a conventional gear-
type transmission which has only four
or five fixed speeds. At those fixed
speeds, of course, the full horsepower
of the engine is being used, but be-
tween those speeds, either the engine
is running light or it is being lugged
down, which means that some horse-
power being sacrificed. As indicated
at the beginning of the article, it is
just as though the unit was equipped
with a thousand different gear selec-
tions, instead of just four or five, and
the right one was always picked
automatically.
BRAKING ON GRADES-T he
hydraulic torque converter is not free-
wheeling; in other words, when de-
scending steep grades where the load
is pushing the machine, the torque
converter will still transmit the torque,
and permit the compression of the
engine and other devices, such as a
hydrotarder or Electrotarder, to be
used in keeping the machine slowed
down to a safe speed. The operator
has only to pick the right gear for
safety, depending upon t h e load,I-
on Address Pagel'EXA6
LeTourneau Tech's ' O
Normon O. Gelyon, Edto,
Published semimnrsy by teTorneo Terknical
I nlbtue ond sen 1re I po requ rht ie Edito,
P. 0u so, 1872, Lo,,ye., Tezc.s.
r,mered as Second Coss Matner, Janury 10,
,94 a th. Pe Ofi'ce't ' tonie ' T.'.s,
under bhe Act o1 A.ngvt 2U. 1917.
N eold hNOw the c cepted e behold
NOW is the doy of ol',atn, - I Coithians
6:2.
teTaurneou, Technical Institr, e off~Uolly
recognize degree g'o,'inq ollege, spec -rne
,neoching indusvrol leodership o mechoenkol
e Full inforo a, be hod by
t' 'he R*itr', P.O. 23,Loniew Te..
Pleas.e Send NOW To.
Name.........
st. & No......
City .......................... ....
St.t. .,.. .C -
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LeTourneau Technical Institute. LeTourneau Tech's NOW, Volume 5, Number 11, June 1, 1951, periodical, June 1, 1951; Longview, Texas. (https://texashistory.unt.edu/ark:/67531/metapth1526658/m1/3/?q=%22~1~1%22~1: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu.; crediting LeTourneau University Margaret Estes Library.