Improvements in Electric Lifts.
Year: 1895

page_text: Date of Application, 23rd Dec., 1895
Complete Specification Left, 28th Aug., 1896-Accepted, 3rd Oct., 1896
Improvements in Electric Lifts.
JOHN SANDERS STEVENS and CHARLES GEORGE MAJOR, Engineers, of
Janus Works, Queen's Road, Battersea, in the County of London, do hereby declare
the nature of this invention to be as follows:-
The object of our invention is the elimination of all forms of wheel or toothed
gearing, aud winding drums from suspended electric lifts; and the attainment thereby
of greater smoothness of motion, and increase in pace.
We carry out our invention by applying to suspended electric lifts the same
principle of multiplication of motion which is so well known in connection with
hydraulic lifts, and in the following manner.
We construct the armature shaft of the electric motor, or an extension of same,
in the form of a screw, and mount it in bearings designed to resist end wise motion.
A moving nut traverses the screw carrying with it a group of rope wheels which
may thus be made to approach or recede from another fixed group of rope wheels.
The lifting rope or chain is passed round the two groups of wheels and is hauled
in or paid out respectively as the groups of wheels separate or approach, exactly
as in the case of a hydraulic multiplying cylinder, our nut corresponding to the
ram, and the screw to the cylinder.
Any number of multiplications may be employed.
The security of the screw arrangement is retained, while all vibrations due to
toothed gearing are avoided.
When the arrangement is fixed to work vertically, balance weight is added to
the working nut, and this may balance part of the load as well as the cage.
When the screw is placed horizontally, a balance rope is attached to the moving
nut and pulls in opposition to the cage for the same purpose.
In modifications of the arrangement the nut may be attached to, or form part of
the armature shaft, and the screw be made to travel. Or the screw may be
positively fixed, and the entire electric motor travel along it as a nut.
Or the nut
may be positively fixed, and the entire motor with a screw armature shaft be made
to travel.
Any of the arrangements may be placed vertically, horizontally, or at any
angle, and located at any suitable point in a building, the ropes being led over guide
wheels to the cage.
In electric lifts as hitherto constructed the speed has been limited by practical.
considerations unseparable from the toothed wheel and winding drum arrangement.
But in our device it is obvious that with any given speed in the motor, any required
speed of cage may be attained by suitably pitching the screw, and proportioning the.
number of multiplications.
Dated this Twente third dovre of
mber 1805

page_text: JOHN SANDERS STEVENS and CHARLES GEORGE MAJOR, Engineers, of
Janus Works, Queen's Road, Battersea, in the County of London, 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 object of our invention is the elimination of all forms of wheel or toothed
gearing, and winding drums from suspended electric lifts; and the attainment
thereby of greater smoothness of motion, and increase in pace.
We carry out our invention by applying to suspended electric lifts the same
principle of multiplication of motion which is so well known in connection with
hydraulic lifts, and in the following manner.
We construct the armature shaft A Fig. 1 of the electric motor B, or an
extension of same, in the form of a screw C, and mount it in a bearing D designed
to resist end wise motion. A moving nut E traverses the screw C carrying with it
a group of wheels F which may thus be made to approach or recede from another
.fixed group of rope wheels G. The lifting rope or chain H is passed round the
two groups of wheels F and G and is hauled in or paid out respectively as the
groups of wheels separate or approach, exactly as in the case of a hydraulic
multiplying cylinder, our nut E corresponding to the ram, and the screw Ċ to the
cylinder.
Any number of multiplications may be employed.
The security of the screw arrangement is retained, while all vibrations due to
toothed gearing are avoided by means of our invention.
When the arrangement is fixed to work vertically as in Figs. 1 & 2, balance
weight I is added to the working nut, and this may be of such an amount as would
balance part of the load as well as the weight of the cage J.
When the screw is placed horizontally as in Fig. 3, a balance rope K is attached
to the moving nut E and carries a weight I which pulls in opposition to the cage J
for the same purpose.
In modifications of the arrangement the nut E Fig. 4 may be attached to, or
form part of the armature shaft A, and the screw C be made to travel. Or as in
Fig. 5 the screw C may be positively fixed, and the entire electric motor B travel
along it as a nut, carrying with it the wheels F and balance weight I. Or the
but E may be positively fixed as in Fig. 6 and the entire motor B with a screw
armature shaft C be made to travel.
Any of the arrangements may be placed vertically, horizontally, or at any
angle, and located at any suitable point in a building, the ropes being led over
guide wheels to the cage. Separate balance ropes and weights are used in all
horizontal arrangements as in Fig. 3.
In electric lifts as hitherto constructed the speed has been limited by practical
considerations inseparable from the toothed wheel and winding drum arrangement.
But in our device it is obvious that with any given speed in the motor, any required
speed of cage may be attained by suitably pitching the screw, and proportioning
the number of multiplications.
The usual controlling gear, switches, resistances, and brakes are employed in all
cases, but forming no part of this invention are not described.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
(1.) In a suspended electric lift the combination of an electric motor with a

page_text: Ecrew multiplying device for the purposes set forth as described and shewn in
Figs. 1 to 6
(2.) In a suspended electric lift the combination of an electric motor, a screw
multiplying device, and a balance weight greater in amount than would be required
to balance the cage as shewn in Figs. 1, 2, 4, 5 & 6.
(3.) In a suspended electric lift the combination of an electric motor, a horizontal
screw multiplying device, and a separate balance rope & weight greater in amount
than would be required to balance the cage as described & shewn in Fig. 3.
Dated this Twenty-eighth day of August 1896.
JOHN SANDERS STEVENS.
CHARLES GEORGE MAJOR.