Improvements in Terminals for Electrical Purposes.
Year: 1891

page_text: Date of Application, 16th Mar., 1891
Complete Specification Left, 15th Dec., 1891-Accepted, 16th Jan.. 1892
PROVISIONAL SPECIFICATION.
Improvements in Terminals for Electrical Purposes.
I JAMES PITKIN of 56 Red Lion Street, Clerkenwell, Philosophical Instrument
Maker, do hereby declare the nature of this invention to be as follows:-
The present invention has for its object to obviate the necessity for employing
the expensive metal platinum for electric terminals, in glass instruments, and glow
lamps for electric lighting.
The employment of platinum has hitherto been necessary, owing to the difficulty
of finding another less expensive metal of good conductivity, which will withstand
the blow pipe flame when brought to bear upon it, and the glass in connection
with which it must be used, in the manufacture of glow lamps and electrical
instruments.
In the manufacture of glow lamps, it is usual to take the platinum wires which
are to be used as terminals, and fuse around them a glass table which is afterwards
fused into and becomes the base of the lamp.
If it be attempted to use steel (or other metal which is not objectionable ou
account of its conductive qualities) in this manner, it is found that the melting
point of glass and steel being too nearly alike, the latter is fused as the glass melts
To get over this difficulty, protect the terminal wires with glass or enamei,
preferably in the following manner.
While
1 take the wire from which the terminal is to be formed, and when cleaned
One end of the tube
nicely, insert it into a thin glass tube of suitable diameter.
is closed, and from the other the air is exhausted by means of a pump.
thus exhausted, heat is applied to the outside of the tube, and it collapses and
binds tightly onto the metal within.
Steel terminals thus encased may be welded into glass without difficulty, as the
metal is protected, and does not suffer from such heat as it may be necessary to
apply to the exterior of the tube. At the points where it is necessary to expose
the metal for obtaining the contacts, the glass covering can be chipped off, or
removed by fluoric acid, while the parts which come in contact with the blow pipe
flame, in the process of fitting the terminal into place, remain protected.
Dated this 16th day of March 1891.
NEWTON & SUA,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Terminals for Electrical Purposes.
I JAMES PITKIN of 56 Red Lion Street, Clerkenwell, Philosophical Instrument
Maker, 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 :-
The present invention has for its object to obviate the necessity for employing
the expensive metal, platinum, for electric terminals, in glass instruments, and glow
lamps for electric lighting.
The employment of platinum has hitherto been necessary, owing to the difficulty
of finding another less expensive metal of good conductivity, which will withstand
the blow pipe flame when brought to bear upon it, and the glass in connection
with which it must be used, in the manufacture of glow lamps and electrical
instruments.

page_text: In the manufacture of glow lamps, it is usual to take the platinum wires which
are to be used as terminals, and fuse around them a glass table, which is afterwards
fused into, and becomes the base of the lamp.
If it be attempted to use steel (or other metal which is not objectionable on
account of its conductive qualities) in this manner, it is found that the melting
point of glass and steel being too nearly alike, the latter is fused as the glass melts.
To get over this difficulty, I protect the terminal wires with glass or enamel,
preferably in the following manner.
I take the wire from which the terminal is to be formed, and when cleaned
nicely, I insert it into a thin glass tube of suitable diameter. One end of the tube
is closed, and from the other the air is exhausted by means of a pump. While thus
exhausted, heat is applied to the outside of the tube, and it collapses and binds
tightly onto the metal within.
Under some circumstances, the covering tube may be collapsed onto the metal
wire by heat only, without the assistance of an exhaust pump.
If it is desired to use copper terminals, they should be coated with enamel tubes,
in preference to ordinary glass, as being less liable to fracture under the expansion
of the copper.
Steel or copper terminals thus encased, may be welded into glass without
difficulty, as the metal is protected, and does not suffer from such heat as it may be
necessary to apply to the exterior of the tube.
At the points where it is necessary to expose the metal for obtaining the contacts,
the glass covering can be chipped off, or removed by fluoric acid; while the parts
which come in contact with the blow pipe flame, in the process of fitting the
terminal into place, remain protected.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what
claim is
The employment of metallic terminals for electrical purposes, coated with
ordinary glass or enamel, substantially as described, for the purpose of protecting
the metal, and preventing the fusion thereof, as herein before explained.
Dated this 15th day of December 1891.
NEWTON & SON,
Agents for the Applicant.