Year: 1895

page_text: Date of Application, 19th Dec., 1895-Accepted, 25th Jan., 1896
We CHARLES MARK DORMAN, REGINALD ARTHUR SMITH, and HERBERT
GEORGE BAGGS, all of Ordsal Electrical Works, Salford in the County of
Lancaster, Electrical Engineers 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 :-
Our invention relates to that class of electrical switches in which one or more
moving contact pieces make and break contact with two or more fixed contact
pieces for the purpose of making or breaking one or more electrical circuits or
transferring one or more circuits from one source of supply to another.
To carry out our invention we attach the moving contact pieces or brushes of the
switch to a bar or rod which is carried at two or more points in its length on
rocking levers or links which links are pivoted at one end to fixed points on the
base of the switch and at the other end are pivoted to the bar or rod the
arrangement being such that the bar or rod can be rocked lengthwise backwards
and forwards on the links carrying with it the moving contact pieces of the switch
into and out of contact with the fixed contact pieces.
Referring to the drawings Fig. 1 is a side elevation of our improved switch
Fig. 2 is a plan and Fig. 3 is an end elevation viewed from X.
A1, A2, A3, A4, are fixed contact pieces to which conductors can be attached
by means of the binding screws B1, B2, B3, B4. C1, C2, C3, C4, are the
moving contact pieces which are attached to the bar or rod D. E1, E2, E3 E 4,
are rocking levers or links which are free to turn at one end round pivots F 1, F 2,
attached to the base of the switch and at the other end are attached to the bar or
rod D by means of pivots G 1, G 2. It will be seen that the bar or rod D can be
rocked lengthwise backwards and forwards on the links E1, E2, E3, E4,
carrying with it the moving contact pieces C1, C2, C3, C4, into and out of
contact with the fixed contact pieces A 1, A.2, A. 3, A 4.
The fixed and moving contact pieces of the switch may be made of any form or
combination commonly in use such as spring plates, metal brushes or the like
rubbing in jaws or on solid metal contact pieces. The form of contact shewn in the
drawing consists of a pair of spring plates engaging in a slot or jaw.
It is obvious that any required number of moving contact pieces may be attached
to the bar or rod D, and corresponding fixed contact pieces fitted on the base of
the switch as required by the number of circuits to be controlled.
In cases where it is necessary that some or all of the moving contact pieces
should be electrically insulated from one another we form the bar or rod of wood,
vulcanite, or other insulator and attach the metallic contact pieces thereto, or we
form both rod and contact pieces of metal and insulate the one from the other by
means of insulating plates or bushes. The switch shewn in the drawings is of the
type known as a double pole switch; in this case the two moving contacts C1, C2
are electrically connected and also the two C3, C4 but there is no electrical
connection between C2 and C3. The bar or rod D in this switch is built up of
two flat rods of wood, vulcanite or other insulator with the moving contacts fixed
between them.
When the switch is pushed into the on position the fixed contacts A 1, A 2 are
electrically connected, and also the contacts A 3, A 4, but there is no electrical
connection between A and A2

page_text: It is obvious that our improved form of switch is applicable where it is necessary
to transfer one or more circuits from one source of supply to another by arranging
the moving and fixed contact pieces in such a manner that one of the fixed contact
pieces may be connected to either of two other fixed contact pieces by the change
of position of the moving contact pieces. Thus if the two electrically connected
moving contact pieces C1 C2 and the three fixed contact pieces A 1, A 2, A 3,
were arranged at suitable distances apart the moving contact pieces C1 C2 could
be pushed either into such a position as to connect A 2 to A i, or to connect A 2,
to A 3.
Our improved form of switch may be operated by simply pushing or pulling ot
the bar or rod D, or some piece rigidly attached thereto or may be operated by
means of a lever as described further on or by means of any other well known
mechanical device such as rack and pinion or combination of levers.
Our improved form of switch may be used with or without a spring arrangement
for obtaining a quick break and definite hold on and hold off as described
further on.
H is a spring of a bowed or U or V form as described in our Specification
13410-1894 and 545-1895, the arms of which have a permanent tendency to
open outwards; the two ends of the spring K and L form or are provided with
bearings or pivots round which they can turn in the same plane or in a plane
parallel to that in which the bar or rod D, and the levers or links E 1, E2, E 3, E 4,
move.
One end K of the spring is pivoted to the base of the switch or to soine part
rigidly attached thereto, in the switch shewn the end K is pivoted to a continuation
of the fixed contact piece A 3: the other end L of the spring is pivoted to one or
both of the rocking levers or links E 3, E 4. It will be seen that the points at
which the arms K and L of the spring are pivoted are arranged in such a position
that when the switch is in the on position the pivot. F 2 and the points K and L
are approximately in a straight line and the spring has consequently no tendency
to move the links: as soon however as the switch is moved towards the off position
and the point L is brought to the right in the drawing of the line drawn through F 2
and K the outward pressure of the arms of the spring immediately tends to turn
the links E 3, E 4 round to the right and consequently carries the whole of the
moving parts of the switch into the off position shewn in dotted lines on the
drawing and tends to hold it there. The part of the spring from which the arms
radiate is unconstrained except by the pivoted ends, and when the switch is moved
travels in a circular path round the fixed point K.
M is a lever or handle by which the switch may be operated, it is pivoted at F 2
on the same axis as the links E3, E 4 and gears with the pin or point G2 in the
rod D. The lever or handle is of the kind known as a back lash handle that is to
say it is made of such a form that it may be moved through a certain arc without
moving the other parts of the switch.
The effect of this arrangement is that as soon as the moving contact pieces C 1,
C2, C3, C4, are pulled clear of the fixed contact pieces A1, A2, A3, A4,
by means of the lever, they are free to dart rapidly away, under the influence
of the spring H, however slowly the lever may be pulled as described in Holmes'
Specification 3256-1884.
Our improved switch can if desired be fitted with a cover as shown in Fig. 1,
the handle M projecting through a slot in the cover to allow of its being operated
when the cover is in position.
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 :-
(1) The improved form of electrical switch in which the moving contact pieces
or brushes are attached to a bar or rod which is carried at two or more points in
its length on rocking levers or links which links are pivoted at one end to fixed

page_text: points on the base of the switch and at the other end are pivoted to the bar or rod,
the arrangement being such that the bar or rod can be rocked lengthwise back-
wards and forwards on the links carrying with it the moving contact pieces into
and out of contact with the fixed contact pieces.
(2) The combination of the form of switch specified in Claim 1 with the form
of spring described in Specifications 13410-1894 and 545-1895 substantially as
described and shown in this Specification.
(3) The combination of the form of switch specified in Claim 1 with the form
of spring specified in Claim 2 and the back lash lever handle substantially as.
described and shown in this Specification.
(4) The double pole switch as a whole substantially as described and shown in
this Specification.
Dated this 18th day of December 1895.
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.
HERBERT GEORGE BAGGS.