Improvements in Elevator Brakes.
Year: 1891

page_text: Date of Application, 30th June, 1891-Accepted, 29th Aug., 1891
COMPLETE SPECIFICATION.
Improvements in Elevator Brakes.
I, WILLIAM N. ANDERSON of B. and Third Street, San Rafael, in the County
of Marin, and State of California, United States of America, Merchant, do hereby
leclare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The object of this invention is to provide a safety device or brake for lifts or
elevators capable of automatically controlling the descent of the cage or carriage
or of wholly arresting the same as soon as the normal speed with which the carriage
is to travel is exceeded.
The invention consists of certain parts and details and combinations of the same,
as will be hereinafter fully described and then pointed out in the claims.
Reference is to be had to the accompanying drawings, forming part of this
Specification, in which
Figure 1 is a front elevation of the improvement as applied.
Figure 2 is a transverse section of the same.
Figure 3 is an enlarged sectional front elevation of the catch and the lever
supported by the catch.
Figure 4 is a plan view of the improvement as applied, the elevator posts being
in section.
Figure 5 is a bottom view of the elevator carriage provided with the improvement,
the lever being in a locked position.
Figure 6 is an enlarged face view of one of the brake shoes.
Figure 7 is a transverse section of the same and adjacent parts, on line x-a
Figure 5; and
Figure 8 is a 'rear face view of the same, with part of the carriage in section, on
line y-y Figure 5.
Similar letters of reference indicate corresponding parts in all the figures.
The improved brake, as shewn in the accompanying drawings, is applied to an
elevator A having a carriage B mounted to travel in the usual manner on the posts
or guideways C erected in the elevator shaft. The posts or guideways C are
adapted to be engaged on one of their sides by brake shoes D held in place by
suitable brackets E secured to the under side of the bottom of the clevator
carriage B. Each of the brake shoes D is preferably of the construction illustrated
in Figures 6. 7. and 8. being provided with a metallic casing D' containing a
block D made of rubber or other suitable elastic material. The block D2 extends
beyond the casing D' and is adapted to engage the respective side of the elevator
posts C. On the back of the casings D¹ of the brake shoes D are adapted to act
the eccentrics F secured on the end of a shaft G mounted to turn in suitable
bearings on the under side of the bottom of the carriage B. At or near the middle
of the shaft G is secured a gear wheel G in mesh with a segmental gear wheel H¹
formed on the fulcrumed end of a lever H fulcruned in suitable bearings on the
under side of the bottom of the carriage B. The lever H is weighted by a suitable
weight H2 and its free end is adapted to be engaged by a catch I which serves to
hold the said lever in a horizontal position, as is illustrated in Figures 3 and 5.
The catch I is fitted to slide in a suitably constructed casing J fastened on the
under side of the bottom of the carriage B and provided with a slotted tube .J1
containing a spring J' adapted to press on top of the lever H so as to force the
same out of the slot of the tube J' when the catch I is drawn from underneath the

page_text: end of the lever H. The lower end of the casing J has rounded-off forks J³
between which the lever H is adapted to pass in order to pass into the slot of the
tube to be engaged by the catch I, as shewn in Figure 3. The tube J serves
to guide the free end of the lever. The catch I is provided with a stem I¹ fitted
to slide in a bearing on the casing J and carrying a coil spring Is pressing with one
end against the said bearing and with its other against the enlarged end of the
catch I, as is plainly shown in Figure 1. The spring 12 serves to hold the catch I
in an innermost position so as to prevent accidental displacement of the catch I
from underneath the lever H. The outer end of the stem of the catch I is
pivotally connected by a link [3 with one arm of a bell crank lever K fulcrumed on
the under side of the bottom of the carriage B the other arm of the said bell crank
lever being connected with the upwardly-extending rod or rope K passing through
the clevator carriage B to connect with one end of the lever L fulcrumed on top of
the carriage B. The rod or rope K' is provided with a suitable handle K² within the
carriage B so that the rope can be actuated by the operator of the elevator. On
the top of the free end of the lever L presses the stem N¹ of the governor N of
any approved construction mounted on top of the carriage B and provided with
the usual pulley N° over which passes a belt O extending to one side of the
carriage B and then passing over and under the pulleys O and O2 respectively,
journaled in bearings secured on top of the carriage. The belt after leaving the
pulleys extends vertically in opposite directions throughout the length of the
elevator shaft along one of the posts, the ends of the belt being secured at top and
bottom of the shaft. The carriage in its up and down movement travels with the
pulleys O¹ and O2 on the belt O so that the latter impart a rotary motion to the
governor pulley N2 whereby the governor is actuated and remains in operation as
long as the carriage B ascends and descends in the clevator shaft. It is under-
stood, however, that the governor revolves in opposite directions on its up and
down movement. The lever H is also connected at or near its free end with a
rope Q extending upward through the bottom of the carriage B in and through
the latter to pass over a pulley Q mounted on the ceiling of the carriage B. The
downwardly-hanging end of the rope Q is provided with a ring Q² adapted to be
taken hold of by the operator so as to apply the brakes gradually whenever desired,
the catch I having been previously withdrawn by the operator pulling ou the
handle K2.
The operation is as follows-When the device is in its normal position, the
lever His supported by the catch I, as illustrated in Figures 3 and 5. In this
position, the eccentrics F bear lightly on the brake shoes D so that the latter do
not press on to the posts or guideways C and the elevator carriage B is free to
move up and down in the usual manner. Now, in case the carriage hoisting rope
or the machinery connected with the said rope breaks, the carriage rapidly descends
on the guide posts but as soon as this takes place the speed at which the governor N
is driven increases and the governor stem N' presses on the lever L so as to exert
an upward pull on the rope or rod K¹ thus actuating the bell crank lever K
whereby the catch I is withdrawn from underneath the lever H and the latter is
forced out of the tube J' by the spring J2 and its own weight H. The lever thus
swings downward and by the segmental gear wheel H' engaging the gear wheel G'
turns the latter, thus imparting a rotary movement to the shaft G which moves the
eccentrics F against the brake shoes D so that their clastic blocks D2 are forced
against the posts or guideways C. The carriage B is thus braked and either
remains stationary or moves slowly down to the bottom of the shaft. The weighted
lever I can be reset quickly by the operator pulling on the handle Q of the rope Q
so that the lever H swings upward and presses against the catch I so that the latter
slides outward against the tension of the spring 12 and when the lever is above the
said catch I the latter is forced into its normal position underneath the lever H.
Now, in case the operator desires to brake the carriage B at any time he first pulls
upward on the handle K2 at the same time holding on to the rope Q. The pulling

page_text: on the rope or rod K' withdraws the catch I and by the operator then slacking up
on the rope Q permits the lever H to swing downward below the catch I. The
lever H is then entirely under the control of the operator having hold of the rope Q.
By slacking the latter to considerable extent the lever H swings downward and
actuates the eccentrics F as previously described so as to force the brake shoes D
in frictional contact with the posts of the elevator shaft. Thus it will be seen that
the carriage is automatically braked in case of accident as soon as the carriage
exceeds a normal rate of speed and at the same time the brake mechanism is under
the full control of the operator, to be applied whenever desired.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is
1. In an elevator brake, the combination, with brake shoes adapted to engage
shaft posts and arranged on the elevator carriage, of eccentrics adapted to engage
the said brake shoes, a shaft carrying the said eccentrics and provided with a gear
wheel, and a weighted lever fulcrumed on the elevator carriage and provided with
a segmental gear wheel in mesh with the said gear wheel, substantially as shewn
and described.
2. In an elevator brake, the combination, with brake shoes adapted to engage
shaft posts and arranged on the elevator carriage, of eccentrics adapted to engage
the said brake shoes, a shaft carrying the said eccentrics and provided with a gear
wheel, a weighted lever fulcrummed on the elevator carriage and provided with a
segmental gear wheel in mesh with the said gear wheel, a catch adapted to support
the free end of the said lever, and a governor connected with the said catch and
actuated by the movement of the elevator carriage so that when the latter exceeds
a normal rate of speed the said governor withdraws the said catch from underneath
the said lever, substantially as shewn and described.
3. In an elevator brake, the combination, with brake shoes adapted to engage
shaft posts and arranged on the elevator carriage, of eccentrics adapted to engage
the said brake shoes, a shaft carrying the said eccentrics and provided with a gear
wheel, a weighted lever fulcrumed on the elevator carriage and provided with a
segmental gear wheel in nesh with the said gear wheel, a catch adapted to support
the free end of the said lever, a governor connected with the said catch and
actuated by the movement of the elevator carriage so that when the latter exceeds
a norinal rate of speed the said governor withdraws the said catch from underneath
the said lever, intermediate mechanism for connecting the said catch with the said
governor, and a stationary belt secured at top and bottom of the elevator shaft and
passing over the governor pulley, substantially as shewn and described.
4. In an elevator brake, the combination, with brake shoes arranged on the
elevator carriage and adapted to engage the guide posts, of eccentrics adapted to
move the said brake shoes in frictional contact with the guide posts, a shaft
carrying the said eccentrics and provided with a gear wheel, a weighted lever
fulcrumed on the elevator carriage and provided with a segmental gear wheel in
mesh with the said gear wheel, and a rope connected with the said weighted lever
and extending into the elevator carriage to be under the control of the operator,
substantially as shewn and described.
5. In an elevator brake, the combination, with a weighted lever, eccentrics
actuated by the said weighted lever, and brake shoes adapted to be actuated by
the said eccentrics, of a catch adapted to support the free end of the said lever, a
bell crank lever pivotally connected with the said catch, and a rod or rope con-
nected with the said bell crank lever and extending into the elevator carriage to be
under the control of the operator, substantially as shewn and described.
6. In an elevator brake, the combination, with a governor adapted to actuate the
brake shoes, of a stationary belt secured at its ends on the top and bottom of the
elevator shaft, and pulleys journaled on the elevator carriage and over and under

page_text: which passes the said belt to pass around the governor pulley, substantially as
shewn and described.
Dated this 30th day of June 1891. ·
W. N. ANDERSON.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.