Improvements in Electric Switches.
Year: 1888

page_text: Date of Application, 8th Oct., 1888
Complete Specification Left, 5th July, 1889-Accepted, 10th Aug., 1889
PROVISIONAL
SPECIFICATION.
Improvements in Electric Switches.
CHARLES SCOTT SNELL of Culver Park, Saltash, Cornwall Engineer and Designer
do hereby declare the nature of this invention to be as follows :-
The object of this invention is to ensure good electrical connection between a
switch arm and the contact piece when the switch is in the "on" position and this I
effect by the use of a cast metal contact piece and a cast switch arm the vertical faces
of each of which are indented or recessed at intervals, the recesses in the contact
piece being of the same vertical dimensions as the distance between the recesses in the
switch arm and vice-versa. Now each recess in the contact piece being cut at the
level of the intermediate space between any two recesses in the switch arm it follows
that the arm being long enough when the switch is turned on the recesses in the one
are filled by the projections in the other and by putting a horizontal saw cut in each
projection (or that intermediate portion between any two recesses) a certain amount
of "play" is allowed so that contact or connection is readily made by each tongue or
projection independently of its neighbour and a certain amount of squeezing can bo
effected although a casting is often referred to as " rigid."
Now I am aware that in Specification No. 11,054 1886 a switch is described
having interlocking "plates" but thorein the use of castings is distinctly disclaimed,
to use the patentees' own words "In place of the usual arrangement of rigid
castings . we employ a number of rolled or malleable thin flexible metallic
plates." And I wish it distinctly understood that my invention in no case requires
plates and it is evidently impossible to construct a switch using castings upon, the
specification above named. In my invention the contact piece and the switch arm
are each composed of one piece or casting throughout.
D
"
COMPLETE SPECIFICATION.
Improvements in Electrio Switches.
I, CHARLES SCOTT SNELL of Culver Park, Saltash, Cornwall Engineer and
Designer 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 object of this invention is to ensure good electrical connection between a switch
arm and the contact piece when the switch is in the "on" position. The better
to explain my meaning reference is made to the accompanying Drawings in which
it will be seen that I effect my purpose by the use of a cast metal (B Fig. 1) con-
tact piece and a cast metal switch arm (A Fig. 1) the vertical faces of each of which
are indented or recessed at intervals, the recesses in the contact piece being of the
same vertical dimensions as the distance between the recesses in the switch arm and
vice-versa. Now each recess in the contact piece being cut at the level of the
intermediate space between any two recesses in the switch arm it follows that, the
arm being long enough, when the switch is turned "on" the recesses in the one are
filled by the projections in the other and by putting a horizontal saw cut (C Fig. 1)
in each projection (or that intermediate portion between any two recesses) a certain
amount of "play" is allowed so that contact or connection is readily made by each
tongue or projection independently of its neighbour and a certain amount of
squeezing can be effected although a casting is often referred to as "rigid."
Paine 27

page_text: Now I am aware that in Specification No. 11,054 1886 a Switch is described
having interlocking plates but therein the use of castings is distinctly disclaimed and
to use the patentees' own words "In place of the usual arrangement of rigid castings
we employ a number of rolled or malleable thin Hexible metallic plates"
and I wish it distinctly understood that my invention in no case requires plates and it
is evidently impossible to construct a switch having "Castings upon the specification
above named. In my Invention the contact piece and the switch arm are each
distinctly composed of one piece or casting throughout.
دو
Assuming the Switch illustrated in Fig. 1 to have a breadth of 1 inches it would
be suitable for about 500 amperes, in Fig. 2 if the breadth bo 2 inches it will take
1000 amperes or if 14 about 750 amperes, in Fig. 3 the switch being 1 inch broad
the half sections represent proportions to carry 250 and 100 amperes respectively;
the whole being assumed as made of Brass. The general advantages may be
summed up as follows:
Large number of absolutely independent and self adjusting faces.
Destribution of "sparking" over large number of points.
Absolute certainty of contact over 4 points in each tongue.
Small radius to "crossbar" (A Fig. 1) ensuring ease in turning.
Simple in manufacture.
Easy increase in carrying power without increase in radius-simply by adding
to number of tongues.
"Sweet" contact or interlocking action.
Easy adjustment for wear by insertion of knife blade or wedge, in the sawcuts.
Enormous contact surfaces, consequently cool in use.
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:
1st. The construction, or arrangement and combination of the parts of a Switch,
substantially as and for the advantages herein described, in reference to and shown
in the accompanying Drawings.
2nd. The construction in Switches of a series of horizontal tongues and recesses
arranged so as to interlock substantially as and for the advantages herein described, in
reference to and shown in the accompanying Drawings.
Dated this 5th day of July 1889.
C. SCOTT SNELL.