Improvements in Electric Switches.
Year: 1890

page_text: Date of Application, 28th Oct., 1890--Accepted, 10th Jan., 1891
COMPLETE SPECIFICATION.
Improvements in Electric Switches.
I, HERBERT JOHN ALLISON, Patent Agent, of 52 Chancery Lane, London, in
the County of Middlesex, do hereby declare the nature of this invention (a com-
munication to me from abroad by John Alexander Kennedy McGregor, Electrician,
Henry Wallach, Merchant, and Solomon J. Wallach, Merchant, all of 407 Temple
Court, New York, in the County and State of New York, United States of America)
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 Electrical Switches and consists in the devices and com-
binations of devices hereinafter set forth, reference being had to the accompanying
drawings in which :
Figure 1, is a plan view of a single pole switch embodying my invention with the
slide in such position that the circuit is broken;
Figure 2, is a plan view, with the slide in a second position intermediate the first
and that when the circuit is closed;
Figure 3, is a vertical longitudinal sectional view on line a a, Figure 2;
Figure 4, is a plan view of the switch, with the circuit closed;
Figure 5, is a vertical longitudinal sectional view on line y, y, Figure 6;
Figure 6, is a vertical cross sectional view on line 2, 2, Figure 5;
Figure 7, is a plan view of a modified form of the switch in the second position ;
Figures 8 and 9, are sectional views of still other modified forms of the switch, the
first having the wing pivoted, instead of rigidly secured to the slide, and the second
having the wing flat and the inclined plane secured to the terminal arm;
Figure 10, is a plan view of the modification adopted when a double pole switch is
required;.
Figure 11, a plan view of that employed for an arc lamp line, the current being cut.
off from some one arc, and;
Figure 12, a similar view showing the arrangement when the particular division
controlled by the switch is cut in.
The switch is shown in Figures 1-9, as adapted for a single pole switch but it may
be readily altered to make a double pole switch, as shown in Figure 10, or an are
lamp line switch, as shown in Figures 11 and 12. It consists of a box B, in the
bottom of which there is a dovetailed groove 9; near one end there is preferably
arranged a pillow block b, and it is provided with a cover (). It is usually made of
wood rectangular in form, but porcelain would answer equally well or even metal, if
block b, was an insulator and the wires made no electrical contact with the box.
In groove g, is seated a slide S. It has a thumb piece t, a bridge b, two inclined
planes 2, secured to the main body of the slide, and inclined shoulders s, all parts
but the bridge being, preferably non-conductors. One.plane p, might be omitted as
will be shown.
Secured to block b, and extending well forward are two contact pieces d, d', with
offsets at the free ends, usually brass leaf springs, their said free ends being arranged
fo normally rest in a plane a little below the level of the lower ends of planes p, and
with the ends secured upon block, separate wires wc, w¹, are electrically connected.
These contact pieces might be simple strips extending directly inward from the sides
of the box and without offsets but as arranged a greater length of spring is more
conveniently permitted.
The operation of the switch is as follows: The parts being in the position shown
in Figure 1, it is desired to close the circuit. Then the thumb piece is siezed and
the slide moved toward the other end of the groove y', in the cover.
Planes P, pass
under the offset ends of d, d', and raise them up as seen in Figures 2 and 3. As

page_text: S moves on, these pieces pass off the rear ends of planes b, and fall upon bridge b¹,
and the contact is complete from one wire w, through one piece d, the bridge b¹, and
the other piece d', to wire w¹. To break the circuit the slide is moved back,
pieces d, d, pass off bridge b', but under planes p, their rear ends being higher than
bridge ¹, and the circuit is broken. If at this moment the movement of the slide
were reversed, still the circuit would remain broken, for the normal position of the
free ends of pieces d, d', is lower than bridge ¹, and the non-conducting shoulders s,
with their downward and backward inclination would be first to engage pieces d, d',
and would force them still lower.
It therefore follows that the circuit will not be accidentally closed for, before that
can be done, slide S, must be returned to its first position, to do which, planes p, must
force down and ride over the free ends of pieces d, d', which will then rise above the
level of the lower ends of said planes and the switch will be again in position to be
operated to close the circuit.
In Figure 7 as is manifest, but one plane p, is employed, its operation being as
already described. On the other side of slide S, there is no wing and piece d', rests
continuously upon bridge b¹.
Of course pieces d, d¹, might be pivoted so as to act merely by gravity, but the
contact made would not be so perfect as when they are in the form of springs.
Planes p, instead of being part of the body of slide S, might be wings pivoted
thereto, as shown by Figure 8, or the combination might be reversed and the
plane placed upon the contact pieces and flat wings placed upon the slide, as shown
by Figure 9. without departing from the spirit of the invention; but the arrange-
ment shown is the one preferred and especially the relative dimensions of the parts
which ensure that when the slide is near the extremity of the box the circuit is closed
and when near the centre, it is broken. This can easily be remembered or an
indicator can be placed beside groove g¹. The modification shown in Figure 10 will
be readily understood, the only changes being in having four contact pieces instead
of two and arranging the wings to release them all at the same moment, providing
also that the bridge shall extend so as to receive the ends of each set as they fall, and
dividing it into two sections b', and 62, insulated from each other by strips ¹, one of
which sections 61, will bridge the circuit from terminal d, to d¹, and the other, will
bridge that from terminal d³, to d².
In Figures 11 and 12 the slide is extended at the front and bas conducting strips c,
upon the wings but insulated from each other and insulated from the bridge also by
narrow strips i, (shown by heavy black lines) usually at some point of the inclined
plane, made narrower than the ends of the contact pieces and exactly at the same
relative distance from the respective ends of said pieces. w, w, are intended to
represent the wires of some particular lamp and W, W₁, the main line conductor.
When the switch is in the position shown in Figure 11, it will be noticed that the
circuit from W to W1, is completed through bridge b¹, direct, but no current
reaches W w. Now if the slide is moved to the position shown in Figure 12, the
contact pieces d, d', ride over the planes, cross insulations i, and rest on strips c, and
the circuit is from W through d, c, d², w¹, lamp w, d³, c, d, Was is desired, and as
stated, d, d', being wider than i, make contact with c, before they broke contact with
the bridge extensions on the planes and there was therefore no sparking as would
otherwise have been the case.
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
1. In an electrical switch, the combination of two contact pieces, a slide carrying a
bridge and a wing, and an inclined plane arranged in a line drawn parallel to the line
of movement of said slide and through said wing and the free end of the adjacent
piece, secured as described, so that when said slide is moved in one direction until a
line drawn at right angles to its line of movement will pass through the contact piece,
the wing and the incliued plane, said wing will be at one side of said piece and of the

page_text: inclined plane, a portion of said plane will be between a portion of said wing and the
contact piece, and all will be in contact, and when moved further the contact piece
will engage the bridge, all substantially as set forth.
2. In an electrical switch, the combination of two contact pieces, a slide carrying a
bridge and a wing, and an inclined plane arranged in a line drawn parallel to the line
of movement of said slide and through said wing and the free end of the adjacent
contact piece, secured as described, so that when said slide is moved in one direction
until a line drawn at right angles to its line of movement will pass through the
contact piece, the wing and the inclined plane, said wing will be at one side of
said piece and of the inclined plane, a portion of said plane will be between said
wing and the contact piece, and all will be in contact, but when moved in the opposite
direction, from its limit of motion until it reaches the position aforesaid, said wing
will be at the other side of said piece, all substantially as set forth.
3. In an electrical switch, the combination of two contact pieces, a slide carrying a
bridge and an inclined plane located in front of said bridge, one end higher and the
other lower than it, and lower than the normal position of the free end of the
adjacent contact piece, which is itself normally lower than the plane of the bridge,
substantially as set forth.
4. In an electrical switch, the combination of two contact pieces, a slide carrying
a bridge, an inclined plane located in front of said bridge, one end higher and
the other lower than it, and lower than the normal position of the free end of
the adjacent contact piece, which is itself normally lower than the plane of the
bridge, and an inclined shoulder placed below said bridge, substantially as set
forth.
5. In an electrical switch, the combination of two contact pieces with a space
between their free ends, a slide with a body narrower than said space, adapted
to move between said ends, inclined planes of greater dimensions than the space
between the sides of the slide and the adjacent ends of the contact pieces, and
at one end higher and the other lower than said free ends, a bridge secured to said
slide beyond said planes, of greater length than the space between the free ends of
said contact pieces, and at a level higher than the normal position of said free ends,
substantially as set forth.
Dated this 28th day of October 1890.
ALLISON BROS.,
Agents for the Applicant.