An Improvement in Contact Makers for Electric Lamp Holders.
Year: 1893

page_text: Date of Application, 7th Mar., 1893-Accepted, 19th Aug.,
1893
COMPLETE SPECIFICATION.
An Improvement in Contact Makers for Electric Lamp Holders.
I, EDWARD LIONEL JOSEPH of 92 Queen Victoria Street, in the City of
London, Engineer and Electrician, 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, reference being had to the
accompanying sheet of drawings and to the letters and figures marked thereon, that
is to say:
This invention relates to contact makers for electric lamp holders of the kind in
which a tongue or spring is brought into contact with a conductor by means of a
spindle or stem rotating in a sleeve or boss connected with the lamp holder, the
said spindle or stem having on it a pin which takes into and follows a helical or
inclined groove formed in the said sleeve or boss, whereby the said spindle or stem
is moved end wise as it is turned and presses the aforesaid tongue or spring into
contact with the conductor. Heretofore the tongue or spring has been merely
pressed into contact with the conductor by the action of the aforesaid spindle or
Now the object of my
stem without any, or if any, very little, rubbing contact.
improvement is to so construct and arrange the tongue or spring of the contact
maker that when pressed against the conductor it shall rub against the same and
thereby cause the removal from the surfaces of any dirt or other substance that
would prevent their electrical contact. For this purpose I employ the arrangement
shown in the drawings hereto annexed in which
Figure 1 is a sectional elevation of a lamp holder with my improved contact
maker applied thereto, and
Figure 2 is a sectional plan of same taken on line 1-1 of Figure 1.
The
A is the part of the lamp holder casing containing the contact maker, B the
sleeve or boss in which the spindle or stem C works. D is the helical or inclined
groove in which the pin E on the spindle or stem C takes and which imparts the
end wise movement to the said spindle or stem C as above mentioned.
point C of the spindle or stem C is composed of insulating material. F is a
conducting post electrically connected with the spring buffer contact G, and
I is the
H is a conducting post connected with the source of electricity.
contact tongue or spring connected electrically with the post H and urged
by the spring J constantly towards the end of the spindle or stem C.
When the latter is turned by its thumb piece C' so that its pin E, by
following the groove D, moves the said spindle or stem inwards endwise, the
insulated point C₁ of the spindle or stem pushes the tongue or spring I into the
position shown in dotted lines in Figure 2 so as to close the circuit between
the posts H and F. But it will be seen that the end of the spring I, that comes in
contact with the post F, is bent at an angle so that when the said spring I is pressed
against the post the surface of the inclined end of the tongue or spring is caused
to rub against the said post F and any dirt or other matter is thereby pressed out
from between the surfaces. When the spindle or stem C is turned in the reverse
direction, it slides outwards and the tongue or spring I follows it into the position
shown by full lines in Figure 2, breaking the circuit between the posts H and F.
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 :-
The improvement in contact makers for electric lamp holders which consists in
the employment of a contact tongue or spring I having the part which comes in
contact with the conductor so shaped that when pressed against the same its surface

page_text: shall rub thereon so as to remove dirt or other matter from between the surfaces
intended to be brought into electrical contact substantially as hereinbefore described,
and illustrated in the drawings.
Dand h
1 1000
E. L. JOSEPH,
-Per W. H. Beck,
116, Cannon Street, London, Agent.