Year: 1895

page_text: Date of Application, 23rd Mar., 1895
Complete Specification Left, 23rd Dec., 1895-Accepted, 25th Jan., 1896
I WILLIAM JAMES DAVY, of 4 Parolles Road, Upper Holloway, in the County
of London Engineer, do hereby declare the nature of this invention to be as
follows :-
This invention for improvements in electric switches has for its object to provide
a switch for cutting out from a series circuit a lamp or other device, with good
sound contacts, and consists essentially in arranging all the insulated contact
surfaces to form a part of a common cylindrical surface and in making the desired
connections by a sliding cylindrical contact maker fitting in or on the said cylindrical
surface and adapted to be slid axially.
In making a switch suitable for arc lamps arranged in series according to one
arrangement, the contact surfaces are in the form of similar concave semi-cylinders
arranged in pairs at different heights, and supported from the same base. The
semi-cylinders are insulated and those of each pair are opposite one another. Each
contact maker is in the form of a split ring fitting within the cylinder formed by any
pair of semi-cylinders and adapted to connect either pair together. Each split
cylinder may be expanded by a spiral spring and is operated by means of an
internal flange and of two insulating distance washers on a central spindle engaging
the said flange. The whole apparatus may be contained in a cast iron case.
When desired to entirely disconnect the lamp from the main conductors there are
three pairs of semi cylinders and two contact makers operated from the s
spindle. In the upper extreme position the upper pair of semi cylinders connected
to the adjacent ends of the main are connected together and the continuity of the
series circuit is maintained whilst the lamp is cut out being entirely disconnected
from the main. In the lower extreme, position, the adjacent ends of the mains
which are also connected to two lower semi-cylinders at different heights connect
these semi-cylinders respectively to their opposite semi-cylinders that are connected
to the terminals. of the lamp so that the lamp is inserted in the series circuit.
.same
If a dead cut out is not desired two pairs of: semi-cylinders with one. contact
ring are sufficient.
Dated this 23rd day of March 1895.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.
I WILLIAM JAMES DAVY, of 4 Parolles Road, Upper Holloway, in the County
of London Engineer 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 for improvements in electric switches has for its object to provide
a switch for cutting out from a series circuit a lamp or other device, with good

page_text: sound contacts, and consists essentially in arranging all the insulated contact
surfaces to form a part of a common cylindrical surface and in making the desired
connections by a sliding cylindrical contact maker fitting in or
cylindrical surface and adapted to be slid axially.
on the said
In making a switch suitable for arc lamps arranged in series according to one
arrangement, the contact surfaces are in the form of similar concave semi-cylinders
arranged in pairs at different heights, and supported from the same base. The
semi-cylinders are insulated and those of each pair are opposite one another.
Each contact maker is in the form of a split ring fitting within the cylinder formed
by any pair of semi-cylinders and adapted to connect either pair together. Each
split cylinder may be expanded by a spiral spring and is operated by means of an
internal flange and of two insulating distance washers on a central spindle engaging
the said flange.
The whole apparatus may be contained in a cast iron case.
When desired to entirely disconnect the lamp from the main conductors there are
three pairs of semi-cylinders and two contact makers operated from the sanie
spindle. In the upper extreme position the upper pair of semi cylinders connected
to the adjacent ends of the main are connected together and the continuity of the
series circuit is maintained whilst the lamp is cut out, being entirely disconnected
from the main. In the lower extreme position the adjacent end of the mains which
are also connected to two lower semi-cylinders at different heights are connected by
the contact makers to the opposite semi-cylinders that are connected to the
terminals of the lamp so that the lamp is inserted in the series circuit.
If a dead cut out is not desired two pairs of semi-cylinders with one contact
ring are sufficient.
In the accompanying sheet of illustrative drawings
:-
Fig. 1 is a section of a switch constructed according to this invention and
suitable for series are lamps in which a dead cut out is desirable and Figs. 2 plan
and Fig. 3 sectional plan of the same and
Fig. 4 is a diagram showing the connections.
Figs. 4, 5, 6 are similar views of a single pole quick-break switch.
Fig. 7 is a diagrammatic view of the connections.
The three pairs of concave semi-cylindrical contact pieces a¹... a with inter-
mediate insulating distance cylinders 6 are secured between the slate porcelain or
other suitable base c and cover d by the bolts e that are insulated where they pass
through the contact pieces a¹... a. The lower distance cylinder 6 is slightly
longer than the contact pieces. Spaces fare left between the adjacent ends of the
pairs of contact piece a¹...a and suitable terminals 9 are attached to the contact
pieces. The concave surfaces of the pieces a'...a are all parts of a common
cylindrical surface and are all insulated from one another.
Each of the two contact makers is in the form of a spring split ring h¹ h³
adapted to fit within the cylindrical surface formed by any two opposite contact
As shown the
pieces a...a and to exert an outward pressure on the same.
rings are fitted with helical springs i. The rings h¹ h² are fixed axially on the
central spindle by means of insulating discs m bearing on the upper and lower
surfaces and threaded on the spindle and separated by distance pieces n.
spindle is provided with an head or handle o. The switch is operated by moving
the spindle axially so that in its highest position the opposite pieces a'... a² of the
two upper pairs are connected together by the ring and in its lowest position
the opposite pieces a² a* and a³ as of the two lower pairs are connected.
The
Referring to the diagram the upper contact pieces al a² are connected to the
main circuit terminals and a² is also connected to at of the intermediate pieces
and a¹ to a of the lower pieces. The terminals a³ a³ are connected to the lamp
terminals. In the upper position of the contact makers, the current passes from
the terminal of the main, to contact a², contact maker / contact a¹, to
terminal of the main, so that the lamp is cut out of circuit; also the contact
maker is opposite the lower insulating distance cylinder so that the lamp is a
dead cut out.
the

page_text: In the lower position of the contact maker, the current passes from the + terminal
of the main to contacts a contact maker / contact a³ through the lamp, contact a³
contact maker h² contact a to the terminal of the main.
In the modification shown in Figs. 4, 5, & 6, there are only two contact.
pieces a¹ a and one contact maker h¹. The contact maker is raised by raising the
sleeve p that acts first to press the helical spring against the collars on the
spindle i and when the spring is sufficiently compressed, it suddenly raises the contact
maker within the consulating cylinder 6 and breaks the circuit. The circuit is
completed by lowering the sleeve p which forces the contact ring between the
pieces a¹ a³.
The switch shown in Fig. 4 is enclosed in an insulating casing.
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 I
claim is:-
1. A switch comprising two insulated contact surfaces forming part of a common
cylindrical surface, and a sliding spring cylindrical contact maker adapted to be
forced in or on the cylindrical contact surfaces and make firm contact therewith to.
connect them.
2. The improvements in switches substantially as described with reference to
Figs. 1 to 3.
3. The improvements in switches substantially as described with reference to.
Figs. 4 to 6.
Dated this 23rd day of December 1895.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.