Improvements in and relating to Locked Switches for Electric Current Circuits.
Year: 1890

page_text: Date of Application, 1st Nov., 1890
Complete Specification Left, 2nd Dec., 1890-Accepted, 7th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to Locked Switches for Electric
Current Circuits.
We, JOHN ABBOTT ILIFFE, Gentleman, and HENRY BARTON, Engineer, both
of The Acme Electric Works, Ferdinand Street, Chalk Farm, in the County of
London, do hereby declare the nature of this invention to be as follows:-
This invention relates to certain improvements in that class of switches in which,
when the circuit connections are made, the brush or connecting piece between the
contacts is locked in position against vibratory or accidental action, and released
only by pressure properly applied at the handle. The invention constitutes
improvements upon Letters Patent No. 6267 dated 29 April 1887, and No. 18,825
dated 24 December 1888 the object at present in view being to still further
increase the efficiency while reducing the cost of the said switches. We accomplish
this by making cylindrical contacts, instead of face contacts upon a flat plate, as
formerly forming and arranging the brush so as to produce an automatic outward
or radial spring against the cylindrical contact pieces instead of downward pressure,
thus dispensing with the vertical contact spring hitherto employed; means for
compensating for wear upon the contacts; a new method of attaching the handle to
the spindle an improved or cheaper method of constructing and finishing the
contact pieces and of mounting them upon the slate or other base used; and we also
cast solid stops upon the central plate instead of using inserted screw studs or pins
as before.
Each cylindrical contact consists of two brass plates mounted one upon another,
each plate forming an are of a circle. These plates-distinguishable as upper and
lower plates are first formed or cast as a ring, turned and bored in that condition,
and subsequently cut into four pieces; the cost of manufacture being thereby
reduced.
Each lower plate, for a separate contact, is first mounted upon the slate,
porcelain, or other non-conducting base employed, by means of screws passing
through the base from the bottom into tapped holes in the ring plate. A conically
bored bush and terminal is also passed through the base from the bottom and
through a concentric extension of each lower plate, and secured firmly by a nut
screwed upon the upper end of the corresponding terminal. The lower plate is
made flat on its upper surface, to receive the upper plate, with the exception of an
outward rin, which is tapped to receive two or more screws placed horizontally.
The upper plate has an outward flange upon which it is seated upon the lower
plate, while its inward portion stands well up in the form of a segment of a cylinder:
the cylindrical or inner surface forming a contact surface for the brush. Two or
more slotted holes are made through the flange of the upper plate and screws are
made to pass vertically through the same into the lower plate to firmly secure the
two together, and insure perfect conduction. By slightly slackening the vertical
screws, and causing the horizontal screws to bear upon the flange of the upper
plate, the latter is forced inwardly to compensate for wear.
Two cylindrical contacts, made as already described are oppositely mounted upon
a base, with a suitable spindle and base-plate exactly in the centre. The central
spindle carries the locking arm and brush and a coiled spring, and these are free to
turn around the stationary spindle. The spindle also carries the unlocking arm,
securely attached to an ebonite handle, and this latter is screwed to the stationary
spindle by a central screw, so that by taking out the latter the handle may be
removed from the switch when it is desirable to avoid tampering therewith.
The brush is composed of thin plates or leaves of copper, centrally threaded upon

page_text: the spindle, and bent over towards its extremities at about an angle of 45 degrees.
The extremities of the brush are turned in a lathe (or otherwise formed), to be
slightly larger in diameter than the space between the faces of the cylindrical
contacts, and owing to the elasticity imparted by the bending above named, they
may be turned round by the handle and forced within the smaller space between
the two cylindrical contact faces. The outward spring of the brushes, therefore,
serves to automatically make good contacts with the cylindrical faces-even to
making up for a considerable amount of wear-while if this wear becomes excessive,
the cylindrical faces are set inwards by the horizontal screws already mentioned.
The coiled spring serves to break the contact suddenly when the switch is
unlocked, as before, but as the sudden shock was too great in some cases for inserted
screws or pins to withstand, we now cast two stops solidly upon the spindle base-
plate one being to arrest the motion of the handle when the circuit connections
are established, the other, also, serves the same purpose when the circuit is broken.
The first has but little strain upon it, and may be made as before, while the latter
takes the sudden shock due to the coiled spring when arresting the handle and
brush midway between the contacts.
Dated this 1st day of November 1890.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in and relating to Locked Switches for Electric
Current Circuits.
We, JOHN ABBOTT ILIFFE, Gentleman, and HENRY BARTON, Engineer,
both of The Acme Electric Works, Ferdinand Street, Chalk Farm, in the County
of London, 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 certain improvements in that class of electric switches
in which, when the circuit connections are made, the brush, (or connecting piece
between the terminal contacts,) is locked in position against vibratory action or
accidental touch, and can only be released by pressure properly applied at the
handle. The invention constitutes improvements upon Letters Patent No. 6267
dated 29th April 1887, and No. 18,825 dated 24th December 1888; the object
being to still further increase the efficiency, while reducing the cost of the said
switches.
This is accomplished by making cylindrical contacts, instead of face contacts
upon a flat plate, as formerly forming and arranging the contact making brush so
as to produce an automatic outward spring, in a radial direction, against cylindrical
contact pieces thus dispensing with the vertical down pressing spring hitherto
employed to make good contacts; a new method of attaching the handle to the
spindle an improved or cheaper method of constructing and finishing the contact
pieces and of mounting them upon the slate or other base used; and we cast solid
stops upon the central plate instead of using inserted screw studs or pins, as
before.
In the further description of this invention, reference is made to the accom-
panying drawings, in which Fig. 1 is a vertical section through a switch, and
Fig. 2 is a plan of the same.
Each cylindrical contact consists of two brass plates, mounted one upon the
other, each plate forming an arc of a circle. These plates, distinguished as the
lower plate u, and upper plate 6, are first formed or cast as a ring, turned and bored
in that condition, and subsequently cut into pieces, thus reducing the cost of
manufacture.
Each lower plate a--for a separate contact-is first mounted upon the slate or

page_text: C
other non-conducting base c, by screws passing through the base from the bottom
(not shown), into screwed holes in the lower plate a. A conically bored bush d
and terminal e, is also passed through the base from the bottom, and through an
extension of each lower plate a (as shown in Fig. 2), and firmly secured by a nut f
screwed upon the upper end of each terminal e By mounting the lower plate a in
this manner, and as shown in Fig. 2, breakage of the base is avoided. The lower
plate a is flat on its surface with the exception of an outer rim which is screwed to
receive two or more screws g, 4g, placed horizontally. The upper plate is made
with a flange or base on which it is seated on the lower plate a, while its inward
portion stands well up in the form of a segment of a cylinder, which forms an inner
or cylindrical contact surface for the brush. Two or more slotted holes are made
in the seated portion of the upper plate, and screws, are placed vertically
through the same into the lower plate a, to firmly secure the two together, and
ensure perfect conduction. By slackening the vertical screws h, h, and screwing in
the horizontal screws g, g, against the flange of the upper plate, the latter is
forced inwardly to compensate for wear of the contact surfaces, and the screws h, ht,
are again made tight.
Two cylindrical contacts-made as already described-are oppositely mounted
upon a suitable non-conducting base e, with a suitable spindle and base plate j,
exactly in the centre. The central spindle carries the locking arm k, brush 7 and
coiled spring m and these are turned about a quarter of a revolution around the
stationary spindle, against the pressure of the spring m, when the circuit is
established as shown in Fig. 2. The spindle i, also carries the unlocking arm
securely attached to an ebonite handle o, and this is screwed to the stationary
spindle by a central screw p, so that by taking out the latter, the handle o and
unlocking arm n are removable to prevent the switch being tampered with.
The brush is composed of thin plates or leaves of copper, centrally threaded
upon the spindle with its ends bent downward at about an angle of 45 degrees. The
extremities of the brush are turned in a lathe (or otherwise formed), to be slightly
larger in diameter than the space between the interior cylindrical faces of the upper
plates b, b, and owing to the elasticity of the brush imparted by the bending above
named, it may be turned by the handle and easily forced between the contact faces
of bb. The outward spring of the brush, therefore, serves to automatically make
good contacts with the cylindrical faces of b, b-even to compensating for a con-
siderable amount of wear-while if this wear becomes excessive, the cylindrical
faces of b, bare set inwards by the screws g, g, already mentioned.
The coiled spring m, serves to pull round the brush, locking arm k, and
unlocking arm, when the handle o is turned sufficiently for the forward part of the
arm to ride over, and depress the flat spring 7 out of the detent (not shown), on
the locking arm; which suddenly breaks the circuit. But to meet the sudden
shock caused by the release of the spring m, solid stops r,, are cast upon the
base solidly therewith, one being to arrest the arm (as shown in Fig. 1) and
with it the arm m, brush 1, and handle o against the action of the spring m, as
aforesaid the other one (on the left side of Fig. 1) is to limit the turning of the
said parts when the circuit connection is made.
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. The improvements in locked switches for electric current switches, substan-
tially as and for the purpose herein described.
2. In a locked electric switch, a cylindrical contact surface, adjustable for wear,
substantially as and for the purpose described.
3. In locked electric switch, a laminated contact making brush bent and formed
to automatically spring outward against one or more cylindrically formed contact
pieces, substantially as and for the purpose described.
4. In a locked electric switch, the combination of a lower plate a an upper

page_text: plate with holding screws h and adjusting screws g, substantially as and for the
purpose described.
5. In a locked electric switch, the combination of a base j, spindle i, arm n,
handle o and screw p for securing the said arm and handle o to the said spindle
substantially as and for the purpose described.
6. In a locked electric switch, the combination of cylindrical contact surfaces
with a laminated spring brush making contact therewith, substantially as
described.
7. In a locked electric switch, the combination of contact plates adjustable to
compensate for wear, an automatic spring brush making contact therewith, and a
removable handle, substantially as and for the purpose described.
8. In a locked electric switch, the combination of contact plates a and b forming
segments of a circle, with a terminal e, brush d and nut arranged and adapted to
secure the plate a to the base c substantially as described and shown in Fig. 2.
Dated this 29th day of November 1890.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicants.