Improvements in Electric Switches.
Year: 1890

page_text: COMPLETE SPECIFICATION,
Improvements in Electric Switches.
We WILLIAM WINSTANLEY STRODE, of 48 Osnaburgh Street, Regent's Park,
London, Electrical Engineer, and CHARLES GEORGE GILL, of 95 Bartholomew Road,
Camden Road, London, Manager to above, 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 invention relates to certain improvements in electric switches and has for its
object greater simplicity and durability than heretofore.
"We will describe our invention in reference to the accompanying drawings in which
Figures 1 and 2 are side elevations showing respectively the switch "off" and "on,"
and Figure 3 a front elevation of Figure 2, the covers in each case being shown
dotted Figure 4 is a plan of Figure 3 with cover removed. Similar letters indicate
similar parts.
A is a base plate recessed and screwed in the usual manner or otherwise adapted to
receive the cover a, and provided with the usual fixing and wire holes.
Upon the base plate A is a split pillar B preferably tapered as illustrated, and A
and B may be of porcelain or any other suitable non-conducting material either in
one piece or in parts suitably connected. TT are the terminals, S is an arm which
may be constructed of a plain strip of brass, hard white-or other suitable metal bent
round and flattened, or it may be of a solid piece of metal split at its end so as to
form contact pieces ss which in either case are splayed out and thus a natural
resilience is retained in them. The pieces ss are splayed out a little wider than the
terminals TT which are made of corresponding shape, and the engaging edges of both
are slightly bevelled so that the splayed pieces ss may easily enter between the
terminals and the pressure ensures good contacts upon closing circuit. The arm S is
pivotted at 3 and furnished with a springs which throws and retains it out of contact
with the terminals when the switch is "off" and it is provided on its upper surface
with a stop s for the purpose hereinafter explained.
The said arm S is operated by a cam C pivotted in the
have a fixed knob such as c or other preferred handle.
shape and configuration illustrated for the purpose of
positions.
split pillar B which cam may
This cam is of the special
locking the switch in both
In the "on" position Figure 2 the base of the cam bears firmly on the top of the
arm S and can be moved no farther over. A stop is formed on cam C and in the
"off" position Figure 1 it takes against the aforesaid corresponding stop son
the arm S so that the cam cannot be moved further over. This arrangement is of
considerable importance in that it prevents all wear and tear on the cover B. A
porcelain or other fragile and non conducting substance can therefore be used for this
as well as well as the base and pillar instead of the usual metal whereby there is no
liability to short circuiting.
The knob c may if desired be cranked on to the cam C so that when circuit is open
the knob will project centrally and vertically through the cover.
We are aware of the general arrangement of switch commonly known as the
"Tumbler "switch and we lay no claim to any such general arrangement but
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In an electrical switch of the type hereinabove set forth the use of an operating
cam of special form such as is described in reference to C, c, centred in a split
pillar B, which cam will lock the arm S in the on position and will act as a stop to
"
33

page_text: itself in the "off" position by engaging with a stop s* on said arm S substantially as
and for the purpose set forth.
2. In an electrical switch such as is hereinabove set forth the combination of a
base plate A with split pillar B all of porcelain or other non-conducting material
either in one or in parts connected together, a pivotted operating cam such as c, a
split splayed arm such as S constructed as specified and provided with a spring, and
the terminals all arranged substantially as and for the purposes described and
illustrated in the annexed drawings.
Dated this 29th day of July 1890.
J. C. CHAPMAN, Fel. Inst. Patent Agents,
70, Chancery Lane, London, W.C., Agent for Applicants.