Year: 1888

page_text: Date of Application, 9th May, 1888
Complete Specification Left, 8th Feb., 1889
Complete Specification Accepted, 16th Mar., 18
We FREDERIK VILHELM ANDERSEN, of No. 23 Regency Street Westminster,
S.W. Electrical Engineer, and JOHN FORWOOD TAFE, of the same address, Secretary
to Messrs. Latimer Clark Muirhead & Company Limited do hereby declare the nature
of this invention to be as follows :-
This invention relates to improvements in switches applicable for electric lighting
purposes.
According to this invention the electric circuit is made and broken between two
metallic studs fixed opposite to one another at equal distances from the centre of a
piece of insulating material which forms the base of the switch. The switch-bar or
lever, having two arms, is pivoted with its axis through the centre of the base plate
and is fixed to a cylindrical tube which at one end is secured to the handle of the
switch and at the other is fitted so as to allow of its turning easily in another
cylindrical tube fixed in the centre of the base. The inner cylinder contains a helical
spring, which, at one end is fixed to the handle, and at the other to the base of the
switch in such a manner that the spring is always under considerable tension. Two
notches with sloping sides are cut in the fixed tube in which the switch is pivoted and
the tension of the spring causes the two arms of the switch-bar to automatically slide
down into these notches whereby the bar is caused to perform a rotary motion away
from the contact-studs. When the switch is turned on, the bar is moved against the
tension of the spring until the ends of it rest on the top of the two contact-studs and
in this position it locks itself; but if it is moved only slightly from the top of these
studs, the spring causes it to fly instantaneously to the off position rendering it
impossible for the bar to remain in such a position that an electric are could be main-
tained. The switch-bar when turned in one direction until it comes into contact with
the two metallic studs forms a "bridge" for the current across the insulating base and
when reversed it breaks the current in two places simultaneously whereby the
sparking produced by breaking the current is less than when, as is usually the case,
the current is broken only in one place.
1000

page_text: Improvements in Electric Switches.
We FREDERIK VILHELM ANDERSEN, of No. 23 Regency Street, Westminster,
S.W., Electrical Engineer, and JOHN FORWOOD TAFE, lately of the same address,
Secretary to Messrs. Latimer Clark, Muirhead, & Company, Limited, 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 improvements in switcbes applicable for electric lighting
purposes.
In order that this invention may be more clearly explained and readily understood
we append a sheet of explanatory drawings to be hereinafter referred to and which
illustrate our improvements. Figures 1 and 2 shew a sectional elevation and plan
respectively of our improved switch, and the remaining figures shew different views
of the several parts.
According to this invention the electric circuit is made and broken between two
metallic contact-studs, A, A, fixed opposite to one another at equal distances from the
centre of a piece of insulating material, B. The switch-bar or lever, C, is made cross
shaped, with two arms and tubular centre as shewn in figures 3, 4, and 5, and it is
pivoted with its axis through the centre of the insulating base, B. One end of the
tube is secured to the handle of the switch, and the other end is fitted so as to allow
of its turning easily in another tube, D. This latter tube is fixed in the centre of the
base and has two notches with sloping sides on its upper end as shewn at
figures 6 and 7. The contact-studs are made in the form shewn in figures 8 and 9,
having a projection at one end provided with a sloped surface as at, t, a "stop" as at, 8,
and they are each fitted with a contact-spring as shown at, z. A helical spring, E,
which is always under considerable tension and has one of its ends fixed to the handle
and the other to the base of the switch, is placed within the hollow centre of the
cross shaped switch-bar, C.
When the switch is turned to the "on" position the switch-bar is moved against
the tension of the helical spring, E, until it comes to rest on the tops of the contact-
studs, A, A, under and in contact with the springs, z. Upon its being moved only
slightly from the tops of the contact-studs it is caused by the tension of the spring, E,
to automatically slide into the notches, x, of the tube, D, and so to fly instantaneously
to the "off" position, avoiding the possibility of its remaining in such a position
that an electric are could be maintained.
The switch-bar when turned in one direction until it comes into contact with the
metallic studs forms a "bridge" for the current across the insulating base, and when
reversed it breaks the current in two places simultaneously whereby the sparking
produced by breaking the current is less than when, as is usually the case, the current
is broken only in one place.

page_text: Having now particularly described and ascertained the nature of our said Inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
An electric switch in which a cross shaped switch-bar with hollow centre containing
a helical spring under tension, is pivoted in a cylindrical tube with sloped notches at
its upper end, and in which the contact-studs are formed with projections, sloped
surfaces, stops, and contact-springs, substantially as and for the purposes hereinbefore
described.