IMPROVEMENTS IN ELEVATOR STOPS AND MEANS FOR CONNECTING them WITH THE ELEVATOR CAR
Year: 1883

page_text: LETTERS PATENT to Felix Pascalis Canfield, of the City of Boston and
State of Massachusetts, in the United States of America for an Invention
of "IMPROVEMENTS IN ELEVATOR STOPS AND MEANS FOR CONNECTING them
WITH THE ELEVATOR CAR"
(
COMPLETE SPECIFICATION filed by the said Felix Pascalis Canfield at the
Office of the Commissioners of Patents on the 25th June 1883.
FELIX PASCALIS CANFIELD, of the City of Boston, and State of Massachusetts,
in the United States of America, "IMPROVEMENTS IN ELEVATOR STOPS AND
MEANS FOR CONNECTING THEM WITH THE ELEVATOR-CAR,"
This Invention relates to Improvements in Safety Stops for Elevators, whereby
the descent of the elevator-car at a dangerous speed may be instantly arrested,
whether caused by the breaking of the hoisting-rope, or the unwinding of the
same from the hoisting-drum so rapidly as to occasion damage or danger,
especially when the elevator-car is heavily loaded.
In carrying out my Invention I secure to the well posts vertical rack-bars
provided with broad teeth, and attach to the opposite sides of the lower portion
of the elevator-car or platform a guide box containing a loose pinion the teeth of
which engage with the teeth of the said rack-bar, and is thereby caused to
rotate when the said elevator-car or platform is raised or lowered.
And in case the said elevator-car should start to descend at a dangerous speed,
the teeth of the said pinion are brought into contact, or caused to engage also
with notches formed in the top portion of said guide-box, and thereby instantly
arrests the descent of the elevator-car; which action takes place on account of the
said pinion being caused to rotate as it descends, its speed in falling is so far
impeded that the teeth upon its upper portion are brought into contact. with the
said notches in the top portion of the said guide-box, which is free to fall faster

page_text: than the said pinion can fall, and thereby instantly arrests the descent of the
elevator car or platform.
But that my Invention may be fully understood, I will proceed to describe
the same more in detail by aid of the accompanying drawings.
Figure 1. Represents a front elevation of my Invention as connected with
the well posts and elevator-car.
Figure 2. Represents a perspective view of a portion of the same.
Figure 3. Represents an elevation of a portion of a rack-bar, and elevator-
car having secured thereto a guide box containing a loose pinion resting
upon the bottom thereof.
Figure 4. Represents a similar view showing the teeth on the upper portion
of the loose pinion engaged with the notches within the top portion of
the guide-box in position to stop the descent of the elevator-car or platform.
A A, represent the well posts, extending vertically from the bottom to the top
of the elevator well-hole, and having permanently bolted thereto, the vertical rack-
bars B B, provided upon their front faces with broad teeth C, as shown.
D, represents the elevator-car or platform, to the opposite sides of which are
secured the safety guide boxes E E, within which are placed the loose pinions F F,
the teeth upon the lower side of which rest upon the interior lower side, or
bottom portion of said guide-boxes E, and the teeth upon the rear of said pinion F,
engage with the teeth C, of the said rack-bars B, as shown in Figure, 3., said
pinions F rotating within the said guide boxes E in said position when the
elevator-car is raised and lowered at the usual speed. But in case the hoisting-
rope I should break, permitting the elevator-car, or platform D, to drop
suddenly, bringing the notches L, formed in the interior top portion of the said
guide-boxes E into contact with the teeth upon the upper portions of the said
loose pinions F, the said elevator-car D, would be instantly stopped. And in case
the said hoisting-rope I should rapidly unwind from the hoisting drum, occasioning
a descent of the elevator-car D, at a dangerous speed, the said loose pinions F
would be forced into the same position as shown in Figure 4., as in case when
hoisting rope breaks, as above described.
H represents a guide channel formed in and across the guide-box E, and
adapted to receive therein the toothed rack-bar B, together with a friction
guide plate B, and elastic cushion R.
The extremities of the upper and lower sides of the chamber of the guido-
boxes E terminate in faces in the same vertical plane, and constitute the
forward guides provided in the said guide-boxes E.
A horizontal cross-bar S, is secured to the upper ends of the elevator-car or
platform supports T, and is provided at each end with guide-plates N, which guido
and retain the elevator in a true vertical position when it is raised and lowered.
The loose pinions F, are shown in the guide-boxes E, having their retaining
plates removed that their operation may be more easily understood; but when
applied to the elevator-car, or platform, a suitable plate is attached to the said
guide-box E, so as to retain the said loose pinions F, in said position within the
said guide-boxes, as above described.
I have described the said elevator safety-stops, as being secured near the bottom
of the elevator-car, or platform, and one at each side thereof, but I contemplate
that in case greater security be required, that two or more extra pairs, or sets, of
safety-stops, may be applied to an elevator adapted for carrying freight, or liable
to be very heavily loaded.
My invention is adapted to be applied to various other similar uses, connected
with bodies moving in vertical lines, or moving on incline planes, and requiring
safety stops in case of similar accidents as above described.
It will be seen and understood that the action and operation of my said
invention, is perfectly automatic at all times, and under all circumstances.

page_text: Having thus described the nature of my invention, and the manner of
performing the same, I would have it understood that I claim :--
1. An elevator safety-stop, consisting of a vertical rack-bar and a pinion
loosely mounted within a guide-box provided with notches within its top portion
adapted to engage with the teeth of the said pinion, for the purposes set forth.
2. The combination with the vertical rack-bar B, guide - box E having
notches Land containing the loosely mounted pinion F the teeth of which engage
with the teeth C of the said rack-bar, whereby the said pinion may be rotated, as
and for the purposes set forth.
3. The combination with an elevator-car, of the vertical rack-bar, B having
teeth C, of the guide box E, having the channel H and provided with notches L
within its top portion and containing the loosely mounted pinion F the teeth of
which engage with the teeth C of the said rack-bar, whereby said pinion may be
rotated as the elevator is raised and lowered, as and for the purposes set forth.
4. The combination with an elevator-car of the vertical rack-bar, B, having
teeth C, of the guide-box E having channel H, friction plate P, and elastic
cushion R, and containing the loosely mounted pinion F the teeth of which engage
with the teeth C of the said rack-bar, and is rotated thereby when said elevator-
car is raised or lowered, the teeth of said pinion being also adapted to engage with
the notches L formed within said guide-box E, substantially as described, as and
for the purposes set forth.
In witness whereof I, the said Felix Pascalis Canfield, have, hereunto set my
hand and seal this ninth day of June, in the year of our Lord One thousand eight
hundred and eighty three.