The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1922-05-25


Last Word in Brakes.
As usual with induction motor driv-
en- hoists. regenerative braking by the
motor Will be used when lowering AT
| fun speed. But with all this provis-
ion for braking it was felt that there
was still something lacking. some kind
of electric. brake which would have
effect at less than full speeds. some
thing analogous to braking with an
automobile motor on intermediate or
low gear in descending grade. Prac-
tically this effect is to be brought
about by auxiliary electric equipment
for dynamic braking. This equipment
includes small motor generator set
which will run continuously and fur
nish a low voltage direct current sup
ply \ master switch mounted at the
side of the regular motor controlling
master switch, turns the direct cur
rent into the stator coils and produces
a magnetic retarding or dynamic brak-
ing effect on the rotor. This retarda-
ton varies from weak to strong i'm
steps according to several resistance
switch The two master switches are
nterlocked so that only one current,
either the alternating or the direct
can be traversing the stator circuit at
a given time. BY means of the electric
dynamic braking, lowering can be done
at any rate from full speed to about
one- fourth speed. below which the me-
play. During normal lowering opera
tions most of the braking will be either
regenerative or dynamic making it
necessary to use the regular power
service brake only for sporting" of
skips at the various levels With all |
these provisions, this hoist will have
the most complete braking equipment !
of any hoist in the Occur d'Alene dis
trict, or possibly any district.
Multiple Disc Clutch.
Another consideration of prime inn
portance is the design and eOnstruc
ton of the clutches a subject which
has been given much careful study
Upon looking over the field thorough
~ it appeared that only one hoist
has heretofore been
making a hoist clutch which is really
from practically every
So the problem was to
produce clutch of equal merit, and it
is believed that this end has been ac-
and also one or two addi
tional advantages secured. The null
tiple disc automobile clutch was at =
once turned to as being the most likely
type to adapt into good hoist clutch
AS practically every one knows, the
multiple disc clutch is universally used
n the automobile field today He also
Knows that it is highly satisfactory
md withstands almost unlimited Sc
we're usage. If it has not otherwise
come to his attention he will know
hat it is a most desirable piece of
mechanism when he recalls that it ]
surely must have been on the job all
he time doing its work we'll for the
car has been run month in and month
1ut for several years, with never a ,
hought required as to whether or not {
I were equipped with such a thing as
/ clutch.
So with the automobile type as :
starting point, the multiple disc clutch
las been suitably enlarged. strength
med and adapted for the heavier duty
md the greater torque to be trans
nitted, and for the much reduced
peed at which hoist drum shafts re-
rolve Each drum of the new hoist
will be fitted with one of these clutches
If about 24-inch diameter. The discs l
re made of saw steel and each is !
aced with nodded asbestos friction !
All other vital parts are
made of tough steel, cast, forged or !
ar stock to insure against breakage
Zach clutch is set by four bell cranks :
perated by a shifting collar acting
through four pairs of toggles, any two 7
airs of which would serve to keep the :
lutch in engagement. The clutches 1
re operated by hand levers, principal c
Y for the reason that the force re- +
uired to engage the multiple disc type
very much less than is necessary s
or any other kind. +
The hoist is being fitted throughout r
Dr. the "Alemite" system of grease lu-
which has met with such T
avor in the automobile field, and is
lso being used in some of the latest
inds of industrial machinery.
Safety First A
In order to provide the fullest pro-
ection the White raise hoist is being
qupped with two of the latest type
velch safety controllers. combined S
18th dial indicators. In case of over 7
peed or travel at top or bottom in
ither shaft compartment, the Welch
safety on that side instantly acts to
urn ffthe power circuit and to cimul-
3neously set the power brakes on both
runs. The Welch safeties also pro- +
ide that the hosting engineer must
Progressively reduce speed when near
1g upper or lower limits. Failure to
o this simply results in the hOist's c