The Richmond palladium and sun-telegram. [volume] (Richmond, Ind.) 1907-1939, 1911-04-30
AUTOS WITH SCREW
DRIVE WIN SUCCESS
Provides Silent Machines and
Efficient Engines War
rem Noble Says.
ADOPT THE IDEA HERE
British Firms First to Recog-
nize Worm Drive; Popu-
lar Now.
~ WARREN NOBLE.

I0I INOWs
~ WARREN NOBLE.
Worm. or screw gearing. Is among
the oldest mechanical movements and,
until recent years. has been employed
to obtain either great mechanical adj
vantage or n considerable reduction in
speed between related machine parts.
Later developments. however, saw its
as a driving gear for high
err speed mechanisms and while its
reputation as an effective but ineffi.
cient mechanism remained. It's users
began To see greater possibilities for
80 use than they had at first expected.
Worm drive for automobile purposes.
However. ~ counted by many as new
while as a matter OF fact,
It's use commenced with one Of the
earliest, II not the earliest, really sue.
cessful automobiles built In Great
Britain, the Manchester" The max.
ers Of this car developed at the in.
ception OF It's manufacturer special
form OF worm gear which they have
employed continuously since 1897, and
the mechanical success which they I'm.
doubtedly achieved with their worm
gear led to the Dennis company fol-
lowing their example and later. an
other company known as the New
Engine company" adopted similar
practice. These three concerns. how.
ever. constitute the diciples OF worm
driving. and II was not until the adj
vent of more silent engines and gen.
eral reduction in noise that the great
err bulk OF the English manufacturers
took advantage Of the properties which
worm drive provides. Conjunctively,
however, with the created public de-
mand for silence they realized In a
body the necessity for the abolition of
noise In their transn,issions and an in
creased efficiency with the result that
many OF them closely investigated the
merits Of the worm drive and immedi.
ately adopted II for their new models.
Today, a very high percentage Of the
British cars are worm driven. both in
the commercial and pleasure fields.
while weekly reports from Europe In.
dictate that not only are the French
and Germans following In the lead as
quickly as they can accumulate the
necessary experience, but that the bal
ance of the prominent English manu-
facturers are about to adopt the worm
drive az standard in the near future.
In America the same thing obtains
the demand for commercial efficiency
by the large manufacturers and the
undoubted merits of the worm drive
have led to broad spread experimental
investigation and 1t Is an open secret
that not only are very many of the
American firms about to announce
worm driven models in the near fu.
ture, but that certain Of the truck
manufacturers are already decided
converts to its use-notably the Pierce
compa ny.
The engineer. unacquainted with
modern worm driven mechanism will
Immediately bring to his mind single
threaded worm that. as worm in a
steering gear, Is irreversible. and 1t IL
possibly due to these chains of prece-
dent more than anything else that high
efficiency worm gearing Is 80 little
known among the engineering commu-
nifty. In place Of the old single. dou.
BILE. triple. or even quadruple. thread
worms of peculiar tooth formation,
with seven. eight. to as high as fiji
teen threads. or teeth, cut on them.
with very high spiral angles and per.
fcctly reversible. II Is in the multi
plication OF the number Of threads, or
rather in the spira; angle employed.
that the fundamental difference be-
tween the worm gearing of our grand
fathers and the modern high eff
cheney type Of the present day Is con.
centrated.
II ID found that the efficiency rises
very rapidly through the range of an
giles until 30 degree value Is reached
and that from IS degrees to As de-
grees the curve Of efficiency is almost
flat. II the reader will inspect the &C.
complaining chart OF calculated eff.
ciencies Of worm gearing he will no
tice this popularity In the curves and
readily appreciate the principles upon
which modern high efficiency worm
gearing IL constructed.
Scanning these curves and selecting
that plotted with the friction co-effi-
Client at .03 value. which is fair for
new gearing cut under modern condi-
lions. good general idea OF the eff.
cheney values Of modern worm gearing
may be achieved. The writer. who
has very considerable experience in
worm gearing In the past, finds that
the average efficiency Is approximate
ly 90 to 81 per cent. new to as high as
CAS- after continued use. This rise OF
efficiency on the part Of worm gear.
Ing rs it's life proceeds is noteworthy.
II 10 easy. however, to predict the ef
feet since every turn OF gearing
properly mounted and suitably lubri.
Gated simply increased the degree of
polish Of both worm and wheen sur
faces causing them to approach more
nearly the truly smooth condition de-
manded. Thus the efficiency rises and
the liability of wear decreases with
the continued use OF the gear. This
Is decidedly borne out in practice and
In pleasure automobile construction it
II NO uncommon thing to find an axle
that having run better than $4,000
miles In hard service shows no signs OF
wear In the gears. The importance
49, ANm N~cA~