Improvements in Fittings of Incandescent Electric Lamps.
Year: 1892

page_text: Date of Application, 12th Apr., 1892
Complete Specification Left, 12th Jan., 1893-Accepted, 11th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Fittings of Incandescent Electric Lamps.
We, JAMES MCFARLANE, of Munro's Electrical Manufacturing Company
Limited, 9 Holland Place Glasgow, Works Manager, and WILLIAM BURGESS
EDGAR, Electrician, 10 Strone Terrace, Partick, North Britain, do hereby declare
the nature of this invention to be as follows:-
This invention relates to improvements in electric fittings for incandescent
electric lamps, and has for its object to provide a cheap and compact switch
combined with the lamp holder.
In carrying out our invention we nse that form of lamp holder in which contact
pistons actuated by springs, or flat springs, as in the Brush lampholder, are used
for completing the circuit through the lamp. The ordinary bayonet joint lamp
holder is an example of one to which our invention may be applied.
We propose to use one or both of the contact pistons as part of the switch and
to make the make and break take place by movement of the piston or pistons.
One end of the piston is brought through the insulation base of the lamp holder,
and is actuated by a small rod with projecting arm. By turning this rod the arm
lifts the piston out of contact with the metal plate on the top of the glow lamp,
and thus the circuit is broken. By turning the rod back again the piston is allowed
to drop down and remake or complete the circuit.
The make and break may be obtained by means of a bar of spring metal or
elastic material free to move at right angles to the contact piston, and connected to
it by a link. The little spring which usually presses the piston against the contact
piece on the lamp would in this case be arranged to press the piston out of contact,
and the bar with link would be used to press the piston up against the contact piece
of the lamp.
The required motion of the piston may be got by means of a rod having a
wedge formed on it, which when pushed one way or the other will make or break
the contact.
Our invention may also be carried out by causing the make and break to take
place at the end of the piston which is brought through the insulation base of the
holder, similar mechanism being employed for actuating the piston. In all cases
the contact piece of the lamp holder is actuated so as to make and break the
circuit.
Dated this 11th day of April 1892.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Agents.
COMPLETE SPECIFICATION.
Improvements in Fittings of Incandescent Electric Lamps.
We, JAMES MCFARLANE, of Munro's Electrical Manufacturing Company
Limited, 9 Holland Place, Glasgow, Works Manager, and WILLIAM BURGESS
EDGAR, Electrician, 10 Strone Terrace Partick, North Britain, 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 :-
This invention relates to improvements in fittings for electric incandescent lamps,
and has for its object to provide a cheap and compact switch combined with the
11

page_text: In carrying out our invention we use that form of lampholder in which contact
pistons actuated by springs, or flat springs, as in the Brush lampholder, are used for
completing the circuit through the lamp. The ordinary bayonet joint lampholder
is an example of one to which our invention may be applied.
We
e propose to use one or both of the contact pistons as part of the switch and
to make the make and break take place by movement of the piston or pistons.
One end of the piston is brought through the insulation base of the lampholder,
and is actuated by a small rod with projecting arm. By turning this rod the arm
lifts the piston out of contact with the metal plate on the top of the glow lamp,
and thus the circuit is broken. By turuing the rod back again the piston is
allowed to drop down and re-make or complete the circuit.
The make and break may be obtained by means of a bar of spring metal or
elastic material free to move at right angles to the contact piston, and connected to
it by a link. The little spring which usually presses the piston against the contact
piece on the lamp would in this case be arranged to press the piston out of contact,
and the bar with link would be used to press the piston up against the contact piece
of the lamp.
The required. motion of the piston may be got by means of a rod having a
wedge formed on it, which when pushed one way or the other will make or break
the contact.
Our invention may also be carried out by causing the make and break to take
place at the end of the piston which is brought through the insulation base of the
holder, similar mechanism being employed for actuating the piston. In all cases
the contact piece of the lampholder is actuated so as to make and break the
circuit.
We propose to apply our invention to any suitable form of socket lampholder,
either by applying it to the existing contacts if they are suitable, or by introducing
a new part in place of one of the contacts, when they are not suitable, as herein-
after described and by mechanically moving the contact piston toward or away
from the contact plate on cap of lamp, we make and break the circuit and thus
light or extinguish the lamp as may be desired.
One form in which we apply our invention is as follows. Take the present day
well known form of bayonet socket lampholder, with yielding contact pistons or
buffers of well known construction, hereinafter called pistons.
We will describe the invention with reference to the accompanying drawings.
Through a hole or recess A in the insulating base Z of the lampholder, herein-
after called base, and seen more particularly in detailed view Figure 2, we pass
that end of the piston remote from the contact making end. Passing at right
angles to the said hole A. and through the base Z, is another hole B, which serves as
a bearing for and through which passes a rod or spindle C, one end of which being
thicker than the other forms a shoulder D which fits against a corresponding
shoulder E on the base Z, and serves with the aid of the shoulder on the handle F
to retain the spindle in its proper position. On the thin or remote end of the
spindle C which projects through the base Z is attached an insulating or other
handle F. The thick end of the spindle is half checked, and on the eccentric
arm G thus formed rests the end of the piston H. This end of the piston may be
a piece of insulating material such as hardwood, horn, fibre, etc., loosely fitting in the
hole A, or firmly attached to the end of the piston T, and having its bearing
surface I, Figure 1, curved to the same circle as that described by the circumference
of the thick part of the spindle C. The object of this curvature is to give a
comparatively quick break in switching off.
The barrel N is attached to the insulating base in the usual way with a spiral
spring L inside which presses against the piston T and shoulder M, and is used for
the purpose of breaking the contact, and the wires are led in and attached to the
screws in the usual manner. Alongside of this contact and on the same base is
attached the yielding contact. V of well known construction. The whole is enclosed
in a metal case of well known construction, the parts of which are P, Q and R.

page_text: To the point of the piston is attached a yielding contact and contact rubbing
device, which automatically cleans the contact surfaces every time the circuit is
made or broken.
One form is in the application of a split cotter S, Figure 1, with two limbs
made of thin yielding metal such as phosphor bronze, hard brass, steel, etc. with
or without their points copper-plated, and having these points curved outwardly.
This cotter is soldered or otherwise fixed to the piston T and fits into a slot in
the closed end of the barrel N, in which the limbs are free to spread apart but
not to revolve and so bridge across the two contact plates on the cap of lamp,
or otherwise leave the contact plate. The action is this:-When the curved
points are pressed against the contact plate on lamp, by virtue of their peculiar
and yielding nature, they spread apart, moving in a lateral direction across the
contact plate on lamp, and the friction caused by so doing cleans the contact
making surfaces. It will be observed on looking at the cotter S that one leg is
longer than the other. This has the advantage of confining the making and
breaking spark to the long leg, thus keeping the short leg clean for making good
contact.
A second method in which we apply our invention is as follows:-On the end of
the piston which passes into the recess in the base, is mounted a roller H', Figure 5,
free to revolve. The spindle C in this case is much the same as in the other case,
with this exception, instead of its thick end being half checked, it is bevel shaped G',
Figures and 6, and the space between the shoulders E and D is long enough to
accommodate a spiral spring K', Figure 5, through which the spindle passes, and
in which it is free to revolve and travel in a horizontal direction at right angles to
the piston. The object of the spring K' is to press the spindle inwards against the
roller H' on end of piston. In this case the spring L, Figure 1, is dispensed with
in the barrel; otherwise the parts are the same as Figure 1. The action in this
case is as follows:-On turning the spindle C by the handle F the wedge-shaped
point G on the bevelled end of spindle C travels round the circumference of the
roller H, and is pressed outwards against the pressure of the spring K until the
wedge-shaped point G¹ reaches a place ou the circumference of the roller, where it
can impart to the piston a pressure in the direction of the axis of the piston; then
the spindle C is propelled inwards by the pressure of the spring K and acting
wedge fashion forces the piston in a direction away from the bevelled face G¹ on
end of spindle. By turning the spindle C through another half revolution in either
direction the pistou is again propelled in an opposite direction, and contact with the
contact plate is thus made or broken substantially as described.
Another method by which we obtain a rubbing contact which is applicable to
the motion shown in Figure 5 is as follows:-Over the point of the piston and free
to revolve screw fashion fits a cylindrical cap W, Figure 4, closed at one end and
having opposite to one another two slots Xcut in a spiral direction. Passing
through the piston and through these slots, but firmly fixed into the piston is the
pin Y which guides the movement of the cap W. Inside the cap is a spring K
which presses the cap outwards in a direction towards the lamp so that when the
cap is just touching the contact plate on lamp and the piston is pressed still further
into the cap the cap is caused to revolve through a distance and direction determined
by the pin and slots. When we adopt this plan the recess or hole A in the base Z
and the end of the piston entering it are made square so that the piston will not
revolve instead of the W.
сар The action of this peculiar form of switch as a
whole is as follows:-
:- When the spindle C, Figure 1, is turned by the handle F,
the piston T is raised through the depth of the half check against the pressure of
the spring K until it comes in contact with the contact plate on cap of lamp, and
thus completes the circuit. By turning the spindle by the handle through one half
revolution in either direction the piston is released and pressed off by the spring K
and the circuit is broken again. Thus we make and break the contact.
A third method is as follows:-The end of the piston shod with the insulating
piece H, Figure 7. protrudes through the base. Pivoted to the case Q, and opposite

page_text: the end of the piston is the trigger f. This trigger is so shaped that when the handle
is pressed away from the lamp the piston is by the point of trigger g pressed into
contact with contact plate on lamp. When the trigger is pressed in the opposite
direction the piston is again released and pressed out of contact by the spring L,
and the circuit is thus made or broken substantially as described.
Still another method of applying our invention is as follows:-Through the
hole B in the insulating base, Figure 9, passes a rod or spindle C free to move in
a horizontal direction and with the two knobs or handles f¹ attached to its extreme
ends and on which is also carried the wedge shaped projection which is slightly
curved on its upper surface to retain the roller H' when in the on position as in
Figure 8. The roller H¹ and the piston in this case are the same as already
described in Figure 5, but with the addition of the spring L as in Figure 1. The
action in this case is as follows:-When the piston is in the off position and the
spindle is pressed forward by means of the handles or knobs f' then the piston rises
through the depth of the wedge-shaped projection against the pressure of the
spring L until it makes contact with the contact plate on cap of lamp, and the
roller H is held in this position by the curved portion on the wedge-shaped
projection g', as shown in Figure 8. On reversing the action by pressing the
knob forward the wedge-shaped projection is carried clear of roller H¹. The
piston being now free to move, is pressed by the spring L into the off position, and
the circuit is thus made or broken substantially as 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. The combined switch and lampholder in which the make and break is obtained
by motion of the contact piston, substantially as described and illustrated on the
accompanying sheets of drawings.
2. The combined switch and lampholder in which one of the contact pistons is
brought through the insulating base to engage with the mechanism for moving the
piston to obtain the make and break.
Dated this 11th day of January 1893.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Agents.