Improvements in Machinery for Raising and Lowering Persons and Goods, commonly called Elevators.
Year: 1896

page_text: Date of Application, 2nd Mar., 1896-Accepted, 9th May, 1896
COMPLETE SPECIFICATION.
Improvements in Machinery for Raising and Lowering Persons and
Goods, commonly called Elevators.
I, COFRAN ISRAEL HALL, of 216 Mission Street, in the City and County of
San Francisco, in the State of California, United States of America, Engineer,
do hereby declare the nature of the said invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to that class of machinery employed in buildings and in
other places for raising and lowering persons and goods, commonly called hoists or
elevators.
The improvements consist in suspending, raising and lowering a cabin or platform
and loads thereon by means of flexible ropes passing over pulleys in such a manner
that the driving ropes are not wound or made fast to the winding drums, but are
impelled by friction or traction; also consist in so training these ropes around the
traction or driving drums, so that two or more can be employed for safety, all
operating under like conditions; also further consist in providing for the constant
tension and tractive power of such ropes by suspending thereon in part the weight
of the impelling machinery, and in various other features that will be farther
explained by the drawings and set forth by the description to follow.
The objects of this invention are to avoid the use of winding drums, such as are
commonly employed, and maintain the circumstances of operation the same at all
points and distances in the range of movement, and so the machinery can be
prepared without reference to a particular place or range of movement for the
loads raised or lowered, the only variable clement in the apparatus being the
length of the ropes, and thus the main parts of the machinery be reduced to a
uniform manufacture.
A third object of the invention is to maintain on the impelling ropes a constant
strain and tractive force by the weight of the impelling machinery, acting as a
tension weight thereon, although such tension can be derived by other means, such
as an independent weight or a spring without departing from other features of the
invention.
A fourth object of my invention is to provide for safety of persons and the
machinery, irrespective of the power applied, the ropes slipping in case the plat-
form or load is obstructed, there being only frictional connection between the
impelling machinery and the load.
Referring to the drawings:
Fig. 1 is a side elevation of the operating parts of a hoist or elevator, constructed
according to my invention.
Fig. 2 is an opposite or end view of the same, the ropes and range being fore-
shortened in both figures.
Figures 3, 4, 5, 6 and 7 are diagrams indicating different methods of training the
ropes that impel the load and sustain the counterbalancing weights, such arrange-
ment of the ropes depending upon the circumstances of erection; the method of.
operating being essentially the same in the various arrangements shown.
Similar letters of reference are employed to designate like parts in the different
figures of illustration.
Referring now to the drawings, A is a main frame or sole plate on which are

page_text: mounted all the main parts of the impelling mechanism, consisting of a main
housing or containing case B; two tangent wheels CC, driven in the same
direction by the screws or pinions D' D2; two traction or impelling pulleys EE;
idle or diverting pulley E; the driving shaft F and a friction brake G.
The main frame A is pivoted on a bearing at H, set in such a position that
a predetermined portion of the weight of the frame and the superimposed parts will
rest upon the pulley E3 and upon the impelling ropes ...
The tangent wheels CC and the impelling pulleys EE are keyed on the
shafts 1, having hearings K in the housing B, as seen in Figures 1 and 2.
At L is placed the driving power to operate the shaft F, preferably an electric
motor, as indicated by dotted lines in Fig. 1, but such power can be derived from
bands, a steam engine, or any other suitable means, controllable and reversible in
the usual manner, and so arranged that the shaft and traction pulleys E E enn
be revolved in either direction and stopped and started at will.
A clamping brake G is usually applied to the shaft F, so as to assist in arresting
the motion of the machinery, such brake being operated by a fluid piston, an
electric solenoid, or in any other suitable manner to produce the required move-
As, however, this does not constitute a part of the present invention no
detailed description of this portion of the machinery is required.
ment,
Referring now to the main elements, M represents the load to he raised and
lowered, which can be a cabin for passengers or a platform for goods, and Na
counterbalancing weight, which is preferably made as heavy as the cabin or
platform M and one half of the average loads to be raised or lowered thereon, so
the power required to raise or lower will be the same as nearly as variations of the
load will permit, that is, so the impelling power required will be at all times as
nearly uniform as possible.
In the drawing, Figures 1 and 2, the impelling ropes JJ are independent of
the ropes ., on which the luad M is suspended, corresponding in the manner of
connection and operation to Fig. 7 in the diagrams, where, as in the other
diagrams, Figures 3, 4, 5 and 6, the tractive elements of the pulleys E E are
represented by a single pulley at O).
In Figures 1 and 2, and in the diagram Fig. 7, the load M and the counter-
weight N, as is usual for safety, are suspended on a number of ropes J,
passing over the pulley E', which in this case is merely a sustaining or balancing
pulley.
Following now the impelling ropes J J in Figures 1 and 2, the ends of
these are attached at Q and R to the top and bottom of the balance weight N.
Following downward, these ropes pass half around the idle or diverting pulley E,
and thence twice around the traction pulleys E E not side by side, but winding
from the sides of the pulleys E, E towards the center, so that in passing from one
pulley to the other the diagonal or deflection of each rope is more than the distance
between the two adjacent grooves, the ropes then upward, as seen
at P Fig. 2, to the suspending pulleys E E, which can be substituted by one
pulley of larger diameter, over these pulleys and down again to the counterbalance
weight N, where these ropes are fastened at Q to the counterweight N.
In this manner it will be seen the impelling ropes J J make a continuous
circuit, if the counterbalance N be considered as a section of the same, and that
the traction pulleys E E and the diverting pulley E' are all in the bight of these
ropes JJ.
In the drawings, Figures 1 and 2, there are two impelling ropes shown, but it is
evident that if required, a greater number can be used by increasing the grooves in
the pulleys E E E and the pulleys E E at the top accordingly, and when
wound in the manner before described these ropes can all be led with but little
deflection over the idle or diverting pulley E.
The two pulleys E E can be substituted by a single one whoso diameter
will span the distance required, as is shown in the diagram Fig. 7.
The tension required to produce compensation for the stretching of the

page_text: ropes is provided for by vertical movement of the frame A, its weight
producing traction strain on the ropes JJ, suflicient to overcome the gravity of
the load to be raised or lowered. This being predetermined, no traction strain
beyond this can fall on the impelling ropes JJ, and in case of the load M being
obstructed the frame A will rise, and thus permit these ropes to slip on the
pulleys E' E.
If vibrations of the frame A are sensibly communicated to the load MI arrest
such vibrations by means of a hydraulic circulating cylinder and piston, but
this has seldom lieen found necessary in practice, hence is not included in the
drawings.
By this method of applying the motive power to hoists or elevators thero is
gained certain ndvantages, namely: The action is not positive, being by friction
or traction, and capable of slipping in ease the cage or other part becomes
obstructed. The ropes are continually bent in one direction, and not reversed so
as to induce fracture. The weight of the revolving elements is much less than
when the ropes are wound and unwound from druns in the usual manner. There
is provision for constant. and uniform tension of the impelling ropes, imparted by
the weight of the machinery itself; also the advantage that the main frame A and
the machinery thereon can be set in various horizontal positions in respect to the
weight to be raised, or the shaft in which it moves, and at any augle thereto, as
the circumstances of erection may demand.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
In hoisting machinery for raising and lowering persons or goods :-
1. A rope, or ropes, attached to a cabin or platform and impelled by means
of friction or traction pulleys and wound thereon, substantially as shown and
described.
2. The application of a movable weight, consisting preferably of clements or
parts of the operating machinery, resting in the bight of the impelling ropes to
maintain uniform tension thereof, and so the ropes can slip and stop in case the
lond is obstructed.
3. In combination the accessory elements required, such as a counterbalance,,
guiding and sustaining pulleys, to put my above-described invention into practical
operation and use.
Dated this 2nd day of March 1896.
ALLISON BROS.,
Agents for the Applicant.