Improved Means of Suspending Electric Lamps and other Suspended Objects.
Year: 1889

page_text: Date of Application, 26th Nov., 18891
Complete Specification Left, 23rd June, 1890-Accepted, 26th July, 1890
PROVISIONAL SPECIFICATION.
Improved Means of Suspending Electric Lamps and other Suspended
Objects.
I, WILLIAM FAIRMAN BRADNER, of 705 14th Street Denver, Arapahoe County,
State of Colorado, United States of America, Doctor of Dental Surgery, do hereby
declare the nature of this invention to be as follows :-
My Invention relates to a suspension device, and is more especially designed for
electric lamps in which the suspending cable both supports the lamp and conducts the
current.
The Invention is, however, applicable to the suspension of oil lamps, bird-cages, and
other articles.
The Invention consists in the interposition, in the suspension cord or cable, of a
differential pulley, windlass, or drum having peripheries of two diameters from one
of which the cable extends to the ceiling or other point of support and from the other
of which the cord or cable descends to the lamp, the differential pulley (with or with-
out a case) forming a weight which, when the lamp is lifted, gravitates and in
unrolling the cord from the smaller pulley rolls up the slack on to the larger pulley,
the balancing effect of the two pulley surfaces serving to hold the lamp at any point
to which it may be adjusted.
In one form the pulley is made with one large pulley between two smaller ones.
From the latter, two cords or cables extend to the point of support while from the
former a lower section of cord or cable extends to the lamp or other article to be
suspended. When the lamp is an electric lamp, this lower cord is a continuation of
the upper cords twisted together and consists of a central conductor with an insulating
coating. In this form of the device there is no frame or case forming axial bearings
for the differential pulley or drum, but the latter forms its own axis in the wrap of
the cord.
In another form, the differential pulley is a casting with peripheries of different
diameters flanged to prevent the cord running off. The inner side of the larger
pulley is hollowed out or recessed for the sake of compactness and to cause the cord,
which extends from the small pulley to come as nearly as possible in vertical align-
ment with the cord which extends from the large pulley. The cord which extends
from the ceiling is first wound around the smaller pulley a number of times and then
passing through a hole to the periphery of the larger pulley is wound in the same
direction around it an equal number of times and then descends to, and is fastened to,
the lamp which it supports.
The cable may be made continuous or in two detached sections. For suspending
an ordinary oil lamp, a cord of non-combustible stuff or chain is used while for
electric lamps a continuous cord, consisting of a metal cord and an insulating web
or coating, is used two of these cords being twisted together or woven into a tape one
being connected to one end of the line wire and one side of the lamp and the other to
the other end of the line wire and other side of the lamp so as to carry the electric
current to and from the latter.
The differential pulley is provided at its axial line upon its opposite sides with
trunnions which find a bearing in a housing or casing having outlets at the top and
bottom for the cords or cables. This case is constructed in two halves with registering
or coinciding perforated flanges connected by screw nipples or thimbles which hold.
the two sections together. As a modification of this fastening the case sections may
be formed with half nipples with screw threads formed thereon and connected by an
encompassing thimble constructed as a screw nut.
In constructing the differential pulley and its case, it is necessary that it should

page_text: have considerable weight since it acts as a weight to effect by its own gravity one of
the necessary adjustments of the lamp, and for this reason I prefer to make the pulley
(and its case when used) either of metal or of glass.
The operation is as follows: As has been stated, the cord is wound in the same
direction around both the large and small peripheries of the differential pulley, i.e. the
cord extending from the ceiling is wound first around the smaller pulley and then
passing to the large periphery continues in the same direction around the large
pulley so that the section of the cord above the differential pulley and the section
below it both emerge from the pulley on the same side of the vertical line of its axis.
It will be seen, therefore, that the weight of the lamp has a tendency to turn the large
pulley in the one direction while the weight of the differential pulley, its case and all
that is below it, has a tendency to turn the small pulley in the other direction so that
these two forces act in opposition to each other and with the friction of the cord
passing through the case they sufficiently balance each other to cause the lamp to be
suspended in any position without turning the differential pulley in either direction.
If it is desired to adjust the lamp higher, it is simply raised bodily. This relieves the
large pulley of the weight of the lamp and the weight of the pulley and case being
now relieved of antagonism and free to act it gravitates and unrolls the cord from the
small pulley and as it does so it winds up the slack cord below on the large pulley and
as the large pulley revolves the same number of times that the small one does the
greater circumference of the large pulley takes up more of the lower cord than the
small pulley pays out of the upper cord. The result is that the lamp when raised
is held to its raised position by the still taut cord. To lower the lamp, it is simply
pulled down and as the leverage of the lower cord on the large pulley is greater than
that of the upper cord on the small pulley, the large pulley is unwound and the small
pulley is wound up and as the lower cord is paid out from the large pulley faster
than the upper cord is wound on the small pulley the lamp reaches a lower
adjustment.
may not only use my invention for electric lamps and oil lamps but may
construct the cable in the form of a continuous hollow india rubber tube which con-
nects with the gas-pipes at the ceiling and with a drop light below.
In using my adjusting device in electric chandeliers, the differential pulley
may be allowed to play up and down in the central stem of the chandelier a
portion of which stem would in that case be constructed of a diameter sufficient to
receive it.
In adapting my invention to the suspension and adjustment of lamps of different
weight, the differential pulley first referred to may be made hollow to receive shot,
etc., while the other form is provided with pockets for the same purpose, thereby
permitting an exact balance to be established.
Dated this 26th day of November 1889.
COMPLETE SPECIFICATION.
Improved Means of Suspending Electric Lamps and other Suspended
Objects.
I, WILLIAM FAIRMAN BRADNER of 705, 14th Street Denver, Arapahoe County,
State of Colorado, United States of America, Doctor of Dental Surgery, 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 a suspension device more especially designed for electric
lamps in which the suspending cable both supports the lamp and conducts the current.
The Invention is however also applicable to the suspension of oil lamps, bird
cages, and other articles.

page_text: The Invention consists in the interposition in the suspension cord or cable of a
differential pulley, windlass, or drum, having peripheries of two diameters from one of
which the cable extends to the ceiling or other point of support and from the other
of which the cord or cable descends to the lamp, the differential pulley (with or with-
out a case) forming a weight, which, when the lamp is lifted, gravitates and in
unrolling the cord from the smaller pulley rolls up the slack on to the larger pulley,
the balancing effect of the two pulley surfaces serving to hold the lamp at any point
to which it may be set.
Reference is to be had to the accompanying drawings, forming part of this specifica-
tion, in which figure 1 is a perspective view of a simple form of the device. Figure 1ª
is a sectional view of this form of differential pulley. Figure 2 is a side view of
another form of the device. Figures 3 and 4 are sectional views at right angles to
each other illustrating in detail the form of differential pulley and case shewn in
figure 2, and. figure 5 shews in detail a modification of the device for fastening
together the two sections of the case. Similar letters of reference indicate corre-
sponding parts in all the figures.
Referring to figure 1, B B¹ B¹ is a differential pulley having one large pulley B
and two smaller pulley's B' B₁ one small pulley upon each side of the large one.
A A represent two cords or cables extending from the smaller pulley to the ceiling or
other point of support, and A' A' represent the lower sections of cord extending from
the large pulley to the lamp below. When the lamp is an electric lamp these lower
cords are a continuation of the upper cords A A twisted together and consists of a
central conductor with an insulating coating. In this form of the device, there is no
frame or case forming axial bearings for the differential pulley or drum but the latter
forms its own axis in the wrap of the cord.
"
Referring now to figures 2, 3, and 4, A represents the cord chain or cable leading
from the ceiling or other point of support, to the differential pulley and A' is the
section of cord leading from the differential pulley to the lamp below. This cable may be
made continuous or in two detached sections. For suspending an ordinary kerosene
lamp, a cord of non-combustible stuff or chain is used, while for electric lamps a con-
tinuohs cord consisting of a metal cord and an insulating web or coating is used, as
shewn, two of these cords being twisted together or woven into a tape, one being
connected to one end of the line wire and one side of the lamp and the other to the
other end of the line wire and other side of the lamp so as to carry the electric current
to and from the latter. The differential pulley is formed as a single casting with two
peripheries B and B with flanges applied to the same. The pulley B is of much
larger diameter than B₁ and the side of this larger pulley is hollowed out or recessed
tso as to receive the smaller pulley and thus bring their peripheries approximately in
ahe same plane. The object of this is to render the differential pulley more compact
pnd to cause the cord which extends from the small pulley to come as nearly as
cossible in vertical alignment with the cord which extends from the large pulley. The
ord A which extends from the ceiling is first wound around the smaller pulley B' a
number of convolutions and then passing through a hole a to the periphery of the large
pulley is wound in the same direction around it an equal number of convolutions and
then descends to, and is fastened to, the lamp which it supports. The differential
pulley is provided at its axial line upon its opposite sides with trunnions b b which
find a bearing in a housing or casing C which is designed to be constructed in a
symmetrical ornamental shape, with an outlet at the top for the cord A and another
at the bottom for the cord A. This case is conveniently constructed in two halves
with registering or coinciding perforated flanges c c¹ at the outlets and these halves
are connected by screw-nipples or thimbles d d which penetrate the perforated flanges
and hold the two sections together. As a modification of this fastening the case
sections may be formed with half nipples with screw-threads formed thereon and
connected by an encompassing thimble constructed as a screw nut, as in figure 5. If
desired, small friction rollers may be placed inside the case to properly guide the cord
to the peripheries of the pulley.
In constructing the differential pulley and its case, it is nécessary that it should

page_text: have a considerable weight since it acts as a weight to effect by its own gravity one
of the necessary adjustments of the lamp. For this reason, I prefer to make the
pulley (and its case when used) either of metal or of glass. When made of metal the
case is brilliantly polished or plated and ornamented and when made of glass, it is to.
be ornamented with cut glass pendants after the manner of crystal chandeliers.
The operation of this adjusting device is as follows; It will be seen, by reference to
figures 1 and 4, that the cord is wound in the same direction around both the large
and small peripheries of the differential pulley, i.e. the cord extending from the ceiling
is wound first around the smaller pulley and then passing to the large periphery
continues in the same direction around the large pulley so that the section of the cord
above the differential pulley and the section below it both emerge from the pulley on
the same side of the vertical line of its axis. It will be seen therefore that the weight
of the lamp has a tendency to turn the large pulley in the direction of the arrow s
while the weight of the differential pulley, its case, and all that is below it has a
tendency to turn the small pulley in the direction of the arrow t or opposite to pulley B.
It will thus be seen that these two forces act in opposition to each other and with
the friction of the cord passing through the case, they sufficiently balance each other
to cause the lamp to be suspended in any position without turning the differential
pulley in either direction. If it is desired to adjust the lamp higher, it is simply
raised bodily. This relieves the large pulley of the weight of the lamp and the weight
of the pulley and case being now relieved of antagonism and free to act, it gravitates
and unrolls the cord from the small pulley and as it does so it winds up the slack
cord below on the large pulley and as the large pulley revolves the same number of times
that the small one does, the greater circumference of the large pulley takes up more
of the lower cord than the small pulley pays out of the upper cord. The result is that
the lamp when raised, is held to its raised position by the still taut cord. To lower the
lamp, it is simply grasped and pulled down and as the leverage of the lower cord on
the large pulley is greater than that of the upper cord on the small pulley the
large pulley is unwound and the small pulley is wound up and as the lower cord is
paid out from the large pulley faster than the upper cord is wound on the small
pulley the lamp reaches a lower adjustment. In this way the lamp is held at any
adjustment, and is conveniently raised or lowered by simply pushing it up or pulling
it down, preserving at the same time the unbroken electric continuity of the con-
ducting wire without any rubbing contact or other incident of uncertain electrical
connection.
In making use of my invention, I may not only use it for electric lamps and oil
lamps, but may also construct the cable in the form of a continuous hollow india
rubber tube which connects with the gas pipes at the ceiling and with a drop
light below, thus securing in gas drop lights the same advantages of vertical
adjustment.
In making use of my adjusting device in electric chandeliers, the differential
pulley may be allowed to play up and down in the central stem of the chandelier,
a portion of which stem would in that case be constructed of a diameter sufficient
to receive it.
In adapting my invention to the suspension and adjustment of lamps of different
weight, the differential pulley shewn in figure 1ª may be made hollow to receive shot
or other weighty substance while the form shewn in figure 3 is provided with pockets p
on its sides for the same purpose thereby permitting an exact balance to be
established.
I am aware that it is not new to wind up the flexible suspending cord of a lamp by
a spring-actuated pulley and do not claim this arrangement.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is;
1. A suspending device for lamps, etc., consisting of a cord or cable and a differential
pulley, windlass, or drum; of approximate weight to the object to be suspended; inter-

page_text: posed in the length of the cord with the cord extending from the small periphery to
the supporting point above and from the large periphery to the lamp below, substan-
tially as described.
2. A suspending device for lamps, etc., consisting of a flexible cable with electrical
conductors therein, a differential pulley and case of approximate weight to the object
to be suspended with the cable wound as described on both peripheries of the pulley
and extending from the smaller periphery to the supporting fixture above and with
the cable extending from the larger periphery to the lamp below, to balance the same
in any adjustment, substantially as and for the purpose described.
3. The combination, in a lamp hanger, of a flexible cable a differential pulley
arranged in the length of the cable and having two peripheries of different diameters,
the smaller one being arranged partly within the plane of the larger one and the cable
being wrapped around the two peripheries and the ends extending in approximate
alignment, substantially as shewn and described.
4 The combination, in a lamp hanger, of a flexible cable a differential pulley
arranged in the length of the latter and having the cable wound thereupon as described
and an enclosing case made in two halves forming hangers for the pulley and nipples
or thimbles for connecting the two sections of the case, substantially as and for the
purpose described.
5. The combination, in a lamp hanger, of a flexible cable a differential pulley
arranged in the length of the latter and having the cable wound thereon as described
and an enclosing case having two halves joining together on the line of the cable
and provided with thimbles forming both inlets for the cables and connections for the
two sections of the case, substantially as described.
6. The combination, in a lamp hanger, of a flexible cable a differential pulley
arranged in the length of the cable and having two peripheries of different diameters
lying approximately in the same plane, with an opening a for passing the cable from
one pulley to the other and an enclosing case, substantially as shewn and described.
7. In a lamp hanger, the combination of a suspending cord or cable and a
differential pulley interposed in the length of the cord and provided with pockets or
recesses for shot or other weighty material to balance the lamp, substantially as
shewn and described.
8. In a lamp hanger, the combination of a suspending cord or cable, a differential
pulley interposed in the length of the cord, an enclosing case forming bearings for the
pulley and pockets for the reception of shot or weighty material to balance the lamp,
substantially as shewn and described.
Dated this 73rd day of June 12011
lated this 23rd day of luna 1807
W. F. BRADNER.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.