Year: 1886

page_text: Date of Application, 20th Nov., 1886.
Complete Left, 20th Aug., 1887.
Complete Accepted, 30th Sept., 1887.
I, JOHN HENRY HOLMES of 67, Westgate Road Newcastle-on-Tyne, in the county
of Northumberland, Electrical Engineer do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in holders or supports for incandescent
electric lamps and has for object to insure a more perfect contact between the usual
platinum loop connections, and the hooks of the holder by means of which the lamp
is supported.
In most of the holders with which I am acquainted there is often some uncertainty
in the contact with one or other of the hooks, especially if one of the hooks or loops
happens to be a trifle longer than the other.
In this case although there may be a spring or similar device exerting a pressure
on the globe of the lamp tending to force it away from the hooks, still it sometimes
happens that the pressure is principally exerted on one only of the hooks leaving an
uncertain contact between the other hook and its loop thus causing heating and often
destructive arcing at that point.
To remedy this defect I have devised a lamp holder in which the spring is caused
to exert its pressure on that portion of the glass of the globe which is situated between
the two platinum loops, leaving the other parts of the globe without any support
likely to prevent free movement on the part of the lamp when influenced by the
pressure of the spring.
By causing this pressure to be exerted on the part of the globe between the loops
at a point almost equidistant from either of the hooks, the force will be divided so
that each hook receives its due share of the strain so preventing bad contact with one
of the hooks and consequent heating.
Thus a lamp according to my invention may be constructed in the manner described
below:-
The body of the holder is formed of a short cylinder of boxwood having two wire
hooks of similar length projecting from one end at a convenient distance apart and
the hooks are provided with the usual means of electrically connecting them to the
metallic conductors carrying the electric current to the lamp.

page_text: Two small holes about one-sixteenth part of an inch in diameter are drilled through
the cylinder parallel to its axis and at points on a diameter line drawn across the end
of the cylinder at right angles to a line joining the centres of the hooks.
A stiff piece of wire slightly smaller in diameter than the holes is bent twice at
right angles so as to be in the form of three sides of a rectangular parallelogram.
The ends of the wire thus shaped are inserted in two small helical springs having
open spaces between the convolutions so as to admit of compression end ways.
If now the ends of the wire be inserted in the holes mentioned above, the middle
part of the wire will cross between the hooks, and the springs will tend if compressed
to force the middle part of the wire away from the end of the boxwood cylinder.
If whilst the springs are compressed a lamp with the usual platinum loops be placed
on the hooks and then the springs be released, these latter if previously properly
adjusted for length will exert through the bent wire a pressure on the part of the
lamp between the loops tending to cause firm contact between both sets of books and
loops in the manner set forth above.
Dated this Nineteenth day of November 1886
COMPLETE SPECIFICATION.
Improvements in Holders or Supports for Incandescent Electric
Lamps.
I, JOHN HENRY HOLMES, of 67 Westgate Road, in the City and County of
Newcasle-upon-Tyne, Electric Engineer, do hereby declare the nature of said inven-
tion 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 improvements in holders or supports for incandescent
electric lamps and has for its object to insure a more perfect electrical contact between
the usual platinum loop connections and the hooks of the holder by means of which
the lamp is supported.
In most of the holders with which I am acquainted there is often some uncertainty
in the contact with one or other of the hooks, especially if one of the hooks or loops
happens to be a trifle longer than the other.
In this case although there may be a spring or similar device exerting a pressure
on the globe of the lamp tending to force it away from the hooks, so as to make a firm
contact between the surfaces of the loops and the hooks, still it sometimes happens

page_text: that the pressure is principally exerted on one only of the hooks leaving an uncertain
contact between the other hook and its loop thus causing heating and often destructive
"arcing" at that point.
To remedy this defect I have devised a lamp holder in which the spring or springs
is or are, caused to exert pressure on that portion of the glass of the globe which is
situated between the two platinum loops, leaving the other parts of the globe without
any support likely to prevent free movement on the part of the lamp when influenced
by the pressure of the spring.
By causing this pressure to be exerted on the part of the globe between the loops,
at a point almost equidistant from either of the hooks, the force will be divided so
that each hook receives its due share of the strain so preventing bad contact with one
of the hooks and consequent heating.
Thus a lamp holder according to my invention suitable for an ordinary incandescent
lamp may be constructed in the manner described below :-
The body of the holder is formed of a short cylinder of boxwood or other suitable
material having two wire hooks of similar length projecting from one end at a con-
venient distance apart and the hooks are provided with the usual means of electrically
connecting them to the metallic conductors carrying the electric current to the lamp.
Two small holes about one sixteenth part of an inch in diameter are drilled through
the cylinder preferably parallel to its axis and at points on a diameter line drawn
across the end of the cylinder at right angles to a line joining the centres of the hooks.
A piece of stiff wire slightly smaller in diameter than the holes is bent twice at right
angles so as to be in the form of three sides of a rectangular parallelogram. The
ends of the wire thus shaped are inserted in two small helical springs having open
spaces between the convolutions so as to admit of compression endways.
If now the ends of the wire be inserted in the holes, mentioned above, the middle
part of the wire will cross between the hooks and the springs will tend if compressed
to force the middle part of the wire away from the end of the boxwood cylinder. If,
whilst the springs are compressed, a lamp with the usual platinum loops be placed
on the hooks and then the springs be released these latter, properly adjusted for
length, will exert through the bent wire a pressure on the part of the lamp between
the loops tending to cause firm contact between both sets of hooks and loops in the
manner set forth above.
On the accompanying sheet of drawings I shew three different methods in which
my improvements may be applied in each case the holder being adapted for an
ordinary incandescent electric lamp.
Figs. 1, 2 and 3 shew respectively an end and side elevation and a plan of the
method described in my Provisional Specification.
Fig. 4 shews in elevation a modification of the method of applying the springs
with the addition of guides or stops to keep the lamp in position, at right angles to
the line of the loops.
Figs. 5, 6 and 7 shew respectively an end and side elevation and a plan of a holder
with a spring of different construction having a similar adjusting action upon the
lamp which is not shewn.
The same letters refer to the same or equivalent parts on all the Figs.
Referring to Figs. 1. 2 and 3. A is the body of the holder, B B the hooks electri-
cally connected with the conductors by the binding screws. Cis the spring frame
formed of a piece of stiff wire, bent so as to form a seat for the lower portion of the
lamp between the platinum loops D D. The two ends of this frame are passed through
the helical springs E E and through holes in the body of the holder at right angles
to the centre line of the hooks B B moving freely in the holes which are enlarged at
top to receive the bottom ends of the springs E E.
On one side of the frame is a projecting piece F which being pressed by the
thumb or finger forces down the frame against the resistance of the springs to enable

page_text: the loops D D on the lamps to be attached to the hooks B B when being released,
the springs force the frame upward against the projecting portion of the lamp
between the loops making firmn, and practically equal electrical contact between
each loop and hook.
In Fig. 4 the spring frame is formed of two pieces of wire, prolonged upward to
form guides or stops to keep the lamp in position, and a cross bar soldered upon
them projecting at one end to form the thumb piece F by which the frame is pressed
down against the resistance of the springs E E before attaching the loops D D to
the hooks B B. The cross bar of the frame may be bent down in the middle to
form a seat for the projecting portion of the lamp as in Fig. 1.
In Figs. 5, 6 and 7 the spring frame C is so arranged as to act itself in the same
way as the helical springs being formed of a piece of strong wire, the ends of which
are fixed in the body of the holder A, bent into loops EE which give the spring
action and may be pressed down by the finger when the loops in lamp are to be
attached to the hooks B B.
In all the methods of applying my invention which I have shewn, and in the various
modified forms in which it may be carried out, the spring pressure necessary to insure
firm electrical contact between the loops and the hooks is applied at a point on the
lamp situated between the platinum loops, so that by the compensating action of the
spring or springs due to the point of application of the pressure, the pressure
between the loop and the hook on one side is equal, or nearly so, to the pressure
between the loop and the hook on the other side.
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 :-
In a holder for an incandescent electric lamp of the type which has the two
connecting loops projecting from one end of the glass bulb the improvements
consisting of the combination with the holder and its two connecting hooks of a
spring or springs so arranged that the pressure exerted upon the lamp for the purpose
of forcing the loops of the lamp into good electrical contact with the hooks of the
holder is applied at a point on that portion of the lamp situated between the loops so
that the pressure is divided equally, or nearly so, between the two pairs of hooks and
loops substantially in the manner described above.
Dated the 19th day of August 1887