Improvements in the Caps of Incandescent Electric Lamps.
Year: 1896

page_text: Date of Application, 9th Dec., 1896
Complete Specification Left, 26th Aug., 1897-Accepted, 2nd Oct., 1897
PROVISIONAL SPECIFICATION.
Improvements in the Caps of Incandescent Electric Lamps.
We, EDGAR JULIUS SANDER, of Oxford House, No. 102 Cazenove Road, Stoke
Newington, in the County of Middlesex, Electrician, and ARTHUR CLIFFORD, of
No. 50 St. Quintin Avenue, North Kensington, in the same County, Electrician,
do hereby declare the nature of this invention to be as follows:-
Our invention relates to improvements in the caps of incandescent electric
lamps. The object of it is to provide improved means for holding the well known
metal cap to the top of the bulb. Hitherto this has been done by means of
plaster of Paris; but according to our invention, the use of cement is dispensed
with altogether and detachability at will, provided for.
In carrying the invention into effect, we provide a pair of jaws adapted to
embrace the usual and well known tab on the top of the bulb and to fill the cap;
the fit of the cap over and to the sides of the jaws, sufficing to keep them closed
upon the tab and up to each other. The material of the jaws is any non-electric.
They grip the tab by means of cavities in their faces embracing the tab and
engaging with projections thereupon. The relative positions of the projections
and the respective cavities may be reversed.
According to one modification of the invention the present projections from
the sides of the cap, which are provided to engage in the slots of the bayonet
joints of the lamp holder, are replaced by a pair of studs carried on the free ends
of two spring arms held to the respective jaws, and a pair of holes in the sides of
the cap, one on each side, through which the spring arms are adapted to project
the said studs. Each stud stands, preferably, close to the edge of the respective
jaw on that side of the bulb, so as to prevent any tendency of the bulb to rock
when it is in the cap.
Suitable guides are provided, such studs on the jaws and grooves in the cap
and in which they can engage, to make the studs register with the respective
holes in the cap, when the latter is down upon the bulb.
The edge of the cap is, preferably, swaged out to fit over the bulb. The bulb
is detached from the cap by pressing the studs inwards clear of the latter, when
either can be drawn away from the other.
According to the second modification, the cap is or may be open at the top and
be fitted with projections as heretofore to engage in the bayonet joint of the
holder. It is held in its place over the jaws, by a pin which is passed through
the cap side, both the jaws and through or into the other side. The ends of this
pin may form the studs or projections required to engage in the slots of the
bayonet joints above mentioned, or those hitherto in use may be used.
We prefer inclined slots to holes in the cap sides, for the ends of the pin above
described, to rest in, for the reason that such inclination provides for the bottom
edge of the cap and the convex top of the bulb to be brought, close together, by
merely turning them about their respective axes. It is obvious that the hand of
these slots must be opposite to that of the bayonet joint in order that the engage-

page_text: ment of the lamp with the latter may not interfere with the position of the cap
upon the bulb.
Dated this 9th day of December 1896
COMPLETE SPECIFICATION
Improvements in the Caps of Incandescent Electric Lamps.
We, EDGAR JULIUS SANDER, of Oxford House, No. 102 Cazenove Road, Stoke
Newington, in the County of Middlesex, Electrician, and ARTHUR CLIFFORD, of
No. 50 St. Quintin Avenue, North Kensington, in the same County, 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:-
15
11.
1.
Our invention relates to improvements in the caps of incandescent electric
lamps, and has for its object to provide improved means for holding the cap
securely on the lamp bulb, and in a manner which allows of its being more easily
fixed in or detached therefrom when desired.
Hitherto this has been effected by means of cementing the cap to the top of
the glass bulb and providing the cap with side projections and the holder with
slots, so that when the cap and bulb together are inserted in the holder, the pro-
jections on the cap engage in the slots in the holder and form what is termed a
bayonet joint.
In order that our invention may be the better understood we append hereto a
sheet of drawings illustrating it, to which the following specification will have
reference: Figure 1 is a front elevation of a lamp bulb fitted with our improved
lamp-cap illustrating it in its fixed position; Figure 2 is a side elevation of
Figure 1; Figure 3 is a front elevation of a lamp bulb fitted with our improved
lamp-cap illustrating its position before being tightened down on to the bulb,
and Figure 4 is a plan of Figure 2 with the bulb removed.
According to the present invention we discard the use of cement altogether
for fixing the lamp cap to the bulb, and instead thereof employ two jaws a a¹ of
some insulating material, which embrace the apex b of the bulb; but as this por-
tion of the fitting forms the subject matter of previous Letters Patent No. 13496
granted to us and dated 18th June 1896, we will not here further describe it. In
place of the usual side projections on the cap we pass a pin straight through
the metal cap d and insulation blocks a al within it from side to side, leaving a
portion of the said pin projecting on each side of the cap, which when fixing,
engage in the usual slots in the lamp holder. We further provide an oblique or
inclined slot e-which may if desired be corrugated or notched-on each side of
the metal cap, so that when, the bulb f is rotated in the act of fixing the cap to
the bulb, the projecting ends of the pin c are caused to traverse the slots e in an
upward direction, and in so doing, the cap is thereby drawn on to the top of the
bulb f as far as it will go, and the combined friction of the several parts is
sufficient to hold it firmly in position.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. A cap for incandescent electric lamps, consisting of a cylindrical ferrule
having oblique or inclined slots formed in the sides thereof, substantially as and..
for the purpose herein described and set forth.

page_text: 2. A cap for incandescent electric lamps, held to the bulb or lamp glass by
means of a pin passing directly through the cap and insulation blocks within,
from side to side, leaving the ends of said pin projecting, substantially as herein
described and set forth.
3. The combination with an incandescent electric lamp bulb, of a cap con-
sisting of a cylindrical ferrule having oblique or inclined slots formed in the
sides thereof, and a pin passing directly through the cap and insulation blocks
within, leaving the ends of the pin projecting.
4. The method of and means for tightening and securing the cap of an
incandescent electric lamp on to the bulb, by a pin passing through the cap,
working in oblique slots in the said cap adapted to draw the two parts together
substantially in the manner herein described and shown.
Dated the 26th day of August. 1897
PHILLIPS & LEIGH,
No. 22 Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.