Improvements in Screw Elevators.
Year: 1890

page_text: Date of Application (in United Kingdom), 23rd Dec., 1890
Complete Specification Left, 23rd Dec., 1890-Accepted, 25th Apr., 1891
Improvements in Screw Elevators.
I, CHARLES WENTZ FOWLER, of Baltimore, in the State of Maryland, United
States of America, Mechanical Engineer, 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 :-
My invention relates to that class of devices which are used for raising and
lowering clevators and is designated as a "screw-elevator" in which the motion of
the elevator is produced by a nut moved by a revolving screw.
To the nut are
secured sheaves and ropes so arranged that a motion of the nut through a short
distance will cause any desired motion of the elevator.
My invention consists of a peculiar construction of screw-nut sheaves and ropes
by which I accomplish peculiar and excellent results.
In the drawings
Figures 1 and 2 are side elevations of my screw-elevator structure taken at right
angles to each other Figure 2 showing the base of the screw and its mounting in
section.
Figure 3 is a section of the screw showing a top view of the nut guides and
sheaves.
1, is a stand for the vertical screw 10.
2. and 7 are standards carrying bearings in which the shaft 3 rotates.
4. 5. and 6 are three pulleys mounted on the shaft 3. The pulley 5 is keyed to
the shaft while the pulleys 4 and 6 are loose thereon.
8 is a bevelled wheel keyed to the end of the shaft 3 and engaging with
another bevelled wheel 9 keyed to the lower end of the screw 10 by which the
lifting is done.
11, is a seat on the top of the screw-stand 1 which seat is in the form of a
circular table having a rim around its outer edge and provided with a circular
groove in its upper surface in which rest anti-friction balls 13. 13.
12 is a disk keyed to the lower end of the screw 10 and which rests upon the top
of the anti-friction balls 13. 13 by which the weight of the screw is sustained.
have not shown in the drawings a similar antifriction device for receiving the
upward thrust of the screw, caused by the weight of the elevator but it will be
readily seen that a similar structure to that shown below may be employed for the
top of the screw if desired.
22 is a beam, to which the bearing for the upper end of the screw
secured.
14 is a nut engaging with the screw and travelling upon it and having
secured to its sides four arms 15, 15, and 16, 16 which form a right angle
cross.
17, 17 are two sheaves or pulleys journalled upon the arms 15, 15.
18, 18 are holes through the ends of the arms 15, 15, through which holes
pass guide-rods 19, 19, which are secured to the stand' at the lower end and to
the beam 22-above or to a plate attached thereto.

page_text: 20, 20 are holes through the end of the arms 16, 16, through which pass
guide rods 21, 21 which are secured in the same manner as the rods 19 and
which serve together with the rods 19 to guide the nut 14 and the sheaves or
pulleys 17 as they move up and down as the nut runs on the screw 10.
23 is a cord secured at its ends to the beam 22 at 24, passing downward from one
of the points of attachment 24 under one of the sheaves 17 up and over the hanging
sheave or pulley 25 (journalled in a link 26) down and under the second sheave 17
and up to the beam 22 where it is secured at the other point 24.
The link has also journalled in it a sheave or pulley 27 which may be of any
desired size and under which the hoisting rope 28 passes. The said hoisting
rope is secured at the upper end to the link 26 and passes upward and over
the fixed pulley 29, thence downward under the pulley 27 and to the clevator.
The operation of the device is as follows: In the drawings I have shewn the
pulley 5 used to drive the apparatus; but I have not shewn the shifter by which
the belt is shifted from one pulley to another to raise and lower the elevator
because it is an old and well known device. It consists of one open and one
crossed belt both run by one counter-shaft. As before described the pulleys 4
and 6 are loose on the shaft 3 and the pulley 5 is tight thereon. The pulleys 4
and 6 are also about twice as broad as the pulley 5.
When it is desired to shift the belts to cause the elevator to ascend or descend
they are moved simultaneously and either one or the other thrown upon the tight
pulley 5, when it will turn backward or forward as the case may be. When it is
desired to stop the elevator the shifter is thrown half way and both belts remain
upon the loose pulleys. The shaft 3 turns the wheel 8 which engages with the
.wheel 9 and turns it.and the screw 10 which causes the nut 14 to ascend or descend
in accordance with the direction of the motion of the screw.
The rope 23 being fixed to the beam 22 at the points 24, 24 and passing under
the pulleys 17 up and over the pulley 25 will cause the pulley 25 to ascend or
descend as the nut 14 ascends or descends but it will travel through. twice the
distance travelled. by the nut in consequence of the double line of rope.
The pulley 25 secured to the link 26 will move with it the pulley 27 and cause
that pulley to ascend or descend. In doing so it will draw the rope 28 up and
down, and thus raise or lower the elevator. The number of pulleys and coils of
the hoisting rope-made-at-this-point-may-be-varied-at_will_to_get_any_desired speed
to the elevator.
Of course I may use the equivalent of ropes such as chains.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
1. In an elevator the combination of a screw, a nut mounted upon the said screw
and moved by it, two sheaves or pulleys journalled to the nut a rope or the like
secured at both ends to a beam, and each end passing under one of the said
pulleys and the loop passing up and over another sheave, which is connected
with an elevator-hoisting rope whereby an elevator car may be raised or lowered.
2. In an elevator the combination of a screw, a nut mounted upon the said
screw and moved by it two sheaves or pulleys journalled to the nut a rope or the
like secured at both ends to a beam and each end passing under one of the sheaves
or pulleys secured to the nut and the loop passing over another pulley which is
suspended in a link in which is journalled another pulley under which passes a rope
or the like secured to the upper end of the link and passing over a pulley journalled
at a fixed point, thence down under the upper pulley of the link, and then up to the
elevator car substantially as described.
D
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.