Safety Attachment for Elevators.
Year: 1898

page_text: Date of Application, 13th Sept., 1898-Accepted, 29th Oct., 1898
Safety Attachment for Elevators.
We, GEORGE EDWARD COOKE, Jeweller, and CHARLES LOCKWOOD COOKE, Jeweller,
citizens of the United States, residing at Clarksville, in the County of Montgomery,
and State of Tennessee, U.S.A., do hereby declare 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 present invention relates to safety attachments for elevators, of the class in
which the safety devices are operatively connected with the cable and breakage of
the latter, or its disconnection from the car is productive of an application of the
devices for stopping the car. One object of the invention is to provide against the
contingency of a failure of the gripping device to coact with the guide-strips or
other parts of the elevator shaft by reason of the same being broken out or its yielding
at the point where the gripping action should take place. Other objects of the
invention are to improve the details of construction and arrangement of parts to
secure the best results in practice.
The invention is fully disclosed in the following specification, of which the
accompanying drawing forms a part, in which :-
Figure 1 represents in side elevation a portion of an elevator shaft and a car with
our improvements applied thereto.
Figure 2 is a section on the line 11-11 of Figure 1 with parts broken
away.
Figure 3 is a similar section illustrating the operation of the safety devices.
Figure 4 is a similar view illustrating the effect produced in the absence of a
guiding strip in the shaft.
Figures 5 and 6 are views corresponding with Figures 1 and 2, illustrating a
modification; and
Figure 7 is a top plan view of the same.
In the drawings forming part of this specification, the separate parts of our
improvement are designated by the same numerals of reference in each of the views,
and in said drawing we have shown at 5, the central vertical supports which form
a part of the elevator shaft, and each of which is provided centrally of its inner side
with a vertical rib or guide 6, and we have also shown a part of the frame of an
elevator car, consisting of the side pieces 7, a top piece 8, and a bottom piece 9.
The side pieces 7, of the car are each provided with two sets of rollers 10, and the
rollers of these sets bear on the opposite sides of the inwardly directed ribs or
guides 6, as clearly shown in the drawing, to form a guide for the elevator car
whereby the friction of the car as it moves up and down through the elevator shaft
is reduced and the movement thereof regulated.
The bottom 9 of the frame of the elevator car is also provided at each side with
two eccentrically mounted wheels or rollers 12, which are preferably serrated or
corrugated on their perimeters which are also adapted under certain conditions to
bear upon or operate in connection with the ribs or guides 6, and pivotally and
eccentrically connected with said wheels or rollers at 13, are rods 14, and pivotally
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page_text: connected with said wheels or rollers at the same point and by means of the same
pivot pins are supplemental rods 16, and the rods 16 are connected at their lower
ends by cross-pieces 17 and secured to the central portion of the bottom 9 of the
frame of the car is a spring 18 the ends of which bear on the cross-pieces 17.
The rods 14 are carried upwardly above the top of the elevator car, and the
upper ends thereof, pass through pivoted levers 19, and are free to move in said
levers, and the upper ends of the rods are provided with nuts or burrs 20 and the
levers 19 are pivoted at 21, to the top of the car frame, and extend inwardly in the
direction of the center of said car frame and pivotally supported at 22, are supple-
mental levers 23, the outer ends of which. bear on the inner ends of the levers 19,
and the inner ends of the supplemental levers bear on a collar or flange 24,
secured to or formed on a bolt 25, which passes through the upper end piece or
cross head 8, of the car frame, and the upper end. of said bolt is provided with a
ring 26, to which the cable 27, is connected.
The wheels or rollers 12, operate as grips, and the operation of the entire
apparatus will be readily understood from the foregoing description; when taken
in connection with the accompanying drawing and the following statement thereof.
It will be understood that the elevator is raised or lowered in the usual manner
and may be operated by any desired device or devices.
It will also be seen that the outer ends of the levers 19, are forked, so that they
may be connected with both of the rods 14, two of which are employed on each
side of the elevator, and if at any time the cable 27, should break or said cable
should become detached from the elevator car or said car should fall for any reason,
the spring 18, at the bottom of the elevator will force the rods 16 downwardly so as
to turn the wheels or rollers 12, and cause them to press upon the ribs or guides 6,
at each side of the elevator shaft, as illustrated in Figure 3, and this operation
would at once result in stopping the downward movement of the car.
It will be understood that as long as the elevator car is supported by the
cable 27, the spring 18 cannot act as above described, the rods 14, being held in
their highest position by the levers 19 and 23.
It will also be understood that the bolt 25, is vertically movable in the top piece
or cross head 8, of the car frame, the extent of this movement depending upon the
space between the collar 24, thereon and the said top piece or cross head 8, and
when the car is suspended by the cable 27, said bolt will be held in the position
shown in Figure 1, and when said cable breaks or is otherwise disconnected from
the car, the bolt 25 will drop or be thrown downwardly by the levers 19 and 23,
and the spring 18 will operate as herein before described.
It will be seen that by employing gripping members of circular form, i.e., eccen-
tries, and by arranging the parts so that the lowest part of the eccentric or the
peripheral surface at the least distance from the center, normally confronts the shaft-
surface, and by connecting the upwardly extending rod with the eccentric so that
said rod normally tends to turn the eccentric in a direction to grip the shaft-
surface, provision is made for effecting a complete rotation of the eccentric in case
the shaft-surface gives way or is broken out, and hence the eccentric, instead of
taking up and maintaining an inoperative position, will immediately re-engage the
shaft-surface and grip the same as soon as an unyielding portion thereof is reached.
In this connection the sliding, engagement between the rod and the lever at the
upper end of the car is advantageous, for when the eccentric continues to turn
after the pin 13 has passed its lowest point, the rod slides up through the lever as
indicated in broken lines in Figure 4, and movement of the parts on top of the
car is not required. The loose engagement between the levers 21 and 23 and
between the latter and the bolt 25 may also be of advantage in this connection.
Our improvement is simple in construction and operation and is perfectly adapted
to accomplish the result for which it is intended, and the same may be made as strong
and durable as desired, and it will be apparent that changes in and modifications of
the construction herein described may be made without departing from the spirit of
nr invention or sacrificing its advantages,

page_text: For an example of a modified form of construction embodying the invention herein
disclosed, reference is made to Figures 5, 6 and 7, wherein it will be observed, that
the spring underneath the elevator car is omitted, as are also the rods which connect
the eccentrics with the cross-pieces against which such spring bears. Instead of this
arrangement, the rods 14 have spiral springs 30 connected with them where they
extend alongside the car, said springs being fastened to the latter so that they exert
themselves to draw the rods downwardly and thereby press the eccentrics into locking
position. Instead of the system. of levers herein before described as mounted upon
the top of the car and affording a. means of connection between the draft bolt and the
rods, we employ a spring bar 31 which lies along the top of the car and is. apertured
centrally to accommodate the draft bolt, the latter being of the same form as that
shown in the previous figures, but in this instance instead of its collar acting upwardly
against the inner arms of levers, this collar acts against. the under surface of the
spring bar.
The spring bar is preferably composed of two lapped pieces of strap
steel, which at their outer ends are secured to forked plates 32, the rods 14 passing
through apertures in the arms of the latter the same as they pass through apertures
in the arms of the levers 19 in the former construction. The bar 31 is sufficiently
resilient to adapt itself to different conditions in the connections between the elevator
operating mechanism. and the car, so that the safety devices cannot be impaired in
their operation by variations in such connections.
It will be readily understood that the general operation of this modified construction
is substantially the same as that shown in Figures 1, 2, 3 and 4.
Having thus fully described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. The combination with the elevator car and shaft, of an eccentric pivoted on the
car adjacent to a surface of the shaft, and adapted to drop by gravity into engage-
ment therewith, a rod connected with said eccentric on the side of its pivot
farthest from the said shaft-surface, a sliding draft bolt on the car, and connections
between the same and said rod normally sustaining the latter and the eccentric
through the weight of the car against gravitating tendency, said connections including
provisions permitting movement of the rod and eccentric independently of the bolt,
substantially as described.
2. The combination with the elevator car and shaft, of a gripping member of
circular form eccentrically pivoted on the car with that portion of its periphery which
is nearest the pivot, normally confronting a surface of the elevator shaft, a rod
pivotally connected with said eccentric on the side of its pivot normally further from
said shaft-surface, a sliding draft bolt on the car, and suitable connections between
the same and said rod.
3. The combination with the elevator car and shaft, of an eccentric pivoted on the
car adjacent to a surface of the shaft, and adapted to drop by gravity into engagement
therewith, a rod connected with said eccentric on the side of its pivot farthest from
said shaft-surface, a sliding draft bolt on the car, and levers slidingly engaging the
said bolt and rod respectively and also in engagement with each other.
4. An elevator shaft, the sides of which are provided centrally with inwardly
directed ribs or guides, an elevator car mounted in said shaft and provided at its
opposite sides with rollers which are adapted to fit on said ribs or guides, said car
being also provided at or near the bottom thereof with two eccentrically mounted
wheels or rollers, rods eccentrically and pivotally connected with said wheels or
rollers, and extending upwardly above the elevator car, other rods eccentrically and
pivotally connected with said wheels or rollers and extending downwardly below the
car, a spring secured to the bottom of the car and adapted to operate in connection
with said last named rods at each side of the car, levers connected with the upper
part of the car, and the outer ends of which are connected with the rods which
extend upwardly at each side of the car, supplemental levers pivotally connected
with the top of the car, the outer ends of which bear on the inner ends of said first
named levers, and a vertically movable bolt connected with the top of the car, and

page_text: with which the suspending cable is connected, the inner ends of said supplemental
levers being adapted to operate in connection with said bolt, substantially as shown
and described.
5. An elevator shaft the sides of which are provided with inwardly directed ribs or
guides, a car mounted in said shaft and provided with guide rollers which operate in
connection with said ribs or guides, said car being also provided at or near the lower
end thereof, and at each side with a pair of eccentrically mounted wheels or rollers
which are also adapted to operate in connection with said ribs or guides, rods
eccentrically connected with said wheels or rollers and extending upwardly above
the car, other rods also eccentrically connected with said wheels or rollers, and
extending downwardly below the car, a spring connected with the bottom of the
car and operating in connection with the lower ends of said last named rods to
depress the same, and levers connected with the upper ends of the rods which
extend upwardly, and adapted to operate in connection with a vertically movable
bolt connected with the top of the car, and with which the suspending cable is
connected, substantially as shown and described.
GEORGE EDWARD COOKE.
CHARLES LOCKWOOD COOKE.
F. Wise Howorth,
46, Lincoln's Inn Fields, London, W.C., Agents for the Applicants.