Improvements in Electric Switches.
Year: 1890

page_text: Date of Application, 26th Nov., 1890
Complete Specification Left, 26th Aug., 1891-Accepted, 17th Oct., 1891
PROVISIONAL SIECITIATION.
Improvements in Electric Switches.
I, HENRY BARTON, Engineer, of 24, Ballance Road, Homerton, in the County
of London, do hereby declare the nature of my invention to be as follows:-
My improvements relate more particularly to that class of switches, in which a
spring is employed for placing a two-armed lever from its mid position into its
extreme position to the right or to the left, but they are partly applicable also to
other switches.
The moveable contact faces are at the ends of a two-armed switch lever pivoted
near its centre on a screw situated slightly outside the straight line which connects
the extremities of the lever with each other. In addition to its two main arms, the
said lever has a pair of short arms projecting right and left from the centre of the
lever, one of the said arms contains the fulcrum of the lever and extends beyond
the same, while the other arm carries a pin to which is fixed one end of the
helically coiled main spring mentioned above. The opposite end of the said
spring is attached to a pin fixed on one arm of a three-armed auxiliary lever
adapted to act on the switch lever.
The other two arms of the said lever are at a right angle to the first and
therefore in alignment with each other. Each of these two arms has at its
extremity a hook or detent adapted to come into contact with the extremity of
the short arm of the main lever which contains its fulcrum. The auxiliary lever
is so placed relatively to the main lever, that the auxiliary lever touches the
short fulcrum arm of the main lever in the two extreme positions of the latter, and
that the main lever is retained in either of these positions by the tension of the
spring. In one position one end of the auxiliary lever touches the fulcrum arm of
the main lever on the right side, and in the other position the opposite end of the
auxiliary lever touches the fulcrum arm of the main lever on the left side.
Instead of a helical spring as described above, I may employ an india-rubber
band, or I may omit the spring entirely.
upon
For reversing the position of the auxiliary lever, and consequently the position
of the switch lever, I may employ a handle mounted on an extension of the lateral
arm, or I may act on the pin of the said arm, which holds the extremity of the
main spring. In the latter case a prolongation of the said pin is placed in a fork
fixed to a handle which is pivoted to a bracket secured to the base plate of the
switch in such a manner, that the axis of the said pivot passes perpendicularly
through the base plate at or near its centre. The fork is so wide, that its sides
will not touch the pin, until the handle has been turned a short distance. Each of
the two fixed contact pieces consists of two parts, namely a block screwed the
base plate and provided at one end with an oblique face adapted to come into
contact with a corresponding face at the extremity of the main switch lever, while
the other part is a spring or elastic flap fixed at one end to the rear part of the
block and extending with the front end beyond the contact face of the block, so
that the projecting part of the spring or flap forms with the contact face an acute
angle, into which fits the wedge shaped extremity of the switch lever, when the
circuit is being closed. The contact piece may be provided with two contact
springs or flaps placed at right angles or on opposite sides of the block, and if the
switch lever is pivoted on a screw as hereafter described, the motion of the lever
parallel to its axis may be utilized for pressing the contact face of the lever against
the fixed contact springs. This wedge shaped spring contact may be employed
also in other switches.

page_text: The fulcra of the main switch lever, of the auxiliary lever and of the fork are
formed in a special manner to reduce the cost of manufacture.
Instead of using a smooth pin and a washer, I employ a screw which passes
through a tapped hole in the body of the lever, so that by turning the lever on its
axis it is at the same time screwed up or down on the fulcrum pin. The spindle of
the screw is passed through the base plate from the bottom, until its head is flush
with the base (that is sunk into the latter) after which a nut is placed on the end
of the spindle and screwed down tight upon the base plate, and finally the lever is
screwed upon the part of the spindle which projects above the nut.
This kind of fulcrum is applicable also to other switches.
Dated this 25th day of November 1890.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electric Switches.
I, HENRY BARTON, Electrical Engineer, of 24 Ballance Road, Homerton, in
the County of London, do hereby declare the nature of my invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My improvements relate more particularly to that class of switches, in which a
spring is employed for placing a two-armed lever from its mid position into its
extreme position to the right or to the left, but they are partly applicable also to
other switches.
In the following description reference will be made to the accompanying
drawings Figs. 1 to 5, in which Figs. 1, 14, 4 and 4ª are plans and Figs. 2 and 5
cross sections of two different forms of switches embodying my invention.
The principal part of my invention consists in a special kind of fulcrum for
switch levers. Instead of using a smooth cylindrical or tapered pin and a washer,
I employ a stationary screw spindle which passes through a tapped hole in the
body of the lever, so that the latter acts as a screw nut, which screws itself up or
down on the screw spindle or fulcrum pin, when the lever is turned on its axis
or fulcrum. The said screw spindle is fixed to the base plate or other stationary
part of the switch in any convenient manner, but preferably in the manner shown
by Figs. 2 and 4, that is to say, by passing the screw spindle S through the base-
plate B from the bottom, until its head s is flush with the base, after which a nut N
is placed on the end of the spindle, and screwed down tight upon the base plate (or
upon a washer placed on the same), and finally the switch lever A is screwed upon
the part of the spindle which projects above the nut.
This kind of fulcrum simplifies the manufacture and therefore reduces the cost
of switches, but if used in combination with a sliding contact, as represented
by Figs. 1 to 3 where C, C are U-shaped springs serving as stationary contact
pieces, the screwing action has also the advantage of pressing the moveable contact
faces (that is the extremities a of the lever A) against the upper or lower part of
the stationary contact pieces C, C, thus producing the same effect, as a wedge-
shaped extremity of the switch lever A.
In other respects the switch represented by Figs. 1 to 3 is constructed as
follows:-
The main switch lever A, pivoted on the screw S has a pair of arms a a, the
ends of which are adapted to form sliding contact with the stationary contact
pieces C, shown in detail by Fig. 3.
A third arm placed at right angles to the others and shorter than the same,
carries a grooved friction roller fagainst which rests a spring D made of a wire
bent into a special shape. This spring is attached by a screw e to a two armed

page_text: auxiliary lever E mounted on a screw spindle T serving as a fulcrum similar to the
screw S described above.
Each of the two arms of the lever E has a rounded tooth adapted to come into
contact with the slanting sides of the short arm of the main switch lever A. The
lever E and spring D are so arranged, that the extremities or teeth of the
lever E may act on the short arm of lever A alternately on opposite sides,
according to the position of the switch, so as to reverse its position, and that the
motion of the lever A either way is accelerated by the pressure of the spring D.
The motion of the lever E is effected by means of a handle as shown. g is a stop-
pin fixed to the base plate B; is a pin fixed to the lever E.
The switch represented by Figs. 4 and 5 is constructed as follows:-
The moveable contact faces are at the ends of a two-armed switch lever A¹
pivoted near its centre on a screw S¹ situated slightly outside the straight line
which connects the extremities of the lever with each other. In addition to its
two main arms, the lever A' has a pair of short arms projecting right and left from
the centre of the lever, one of the said arms contains the fulcrum S¹ of the lever
and extends beyond the same while the other arm carries a pin f¹ to which is fixed
one end of the helically coiled spring D'. The opposite end of the said spring is
attached to a pin e fixed on one arm of an auxiliary lever, E' adapted to act on the
switch lever.
The other two arms of the lever E' are at a right angle to the first and therefore
in alignment with each other. Each of these two arms has the shape of a hook
or detent adapted to come into contact with one side of the triangular short arm of
the main lever A¹ which contains its fulcrum. The auxiliary lever E¹ touches the
short fulcrum arm of the main lever A' in the two extreme positions of the latter,
and the main lever is retained in either of these positions by the tension of the
spring D¹. In one position one end of the auxiliary lever E touches the fulcrum
arm of the main lever A' on the right side, and in the other position the opposite
end of the auxiliary lever touches the fulcrum arm of the main lever on the left
side.
Instead of a helical spring, as described above, I may employ an indiarubber
band, or I may omit the spring entirely.
For reversing the position of the auxiliary lever, E¹ and consequently the
position of the switch lever A' I may employ a handle mounted on an extension of
the lateral arm, or I may act on the pin e¹ of the said arm, which holds the
extremity of the main spring. In the latter case a prolongation of the said pin is
placed in a fork fixed to a handle H¹ which is pivoted to a bracket J' secured
to the base plate of the switch in such a manner, that the axis of the said pivot
passes perpendicularly through the base plate at or near its centre. The fork h¹
is so wide, that its sides will not touch the pin, until the handle has been turned a
short distance. Each of the two fixed contact pieces C¹, C¹ consists of two parts,
namely a block c¹ screwed upon the base plate and provided at one end with an
oblique face adapted to come into contact with a corresponding face at the
extremity of the lever A', while the other part is a spring or elastic flap fixed at
one end to the rear part of the block c¹ and extending with the front end beyond
the contact face of the same, so that the projecting part of the spring or flap forms
with the contact face an acute angle, into which fits the wedge shaped extremity of
the switch lever, when the circuit is being closed. The contact piece may be
provided with two contact springs or flaps placed at right angles or on opposite
sides of the block, and if the switch lever is pivoted on a screw as described above,
the motion of the lever parallel to its axis may be utilized for pressing the contact
face of the lever against the fixed contact springs.
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 electric switches, the combination of a screw spindle fixed to the base

page_text: plate, with an oscillating lever mounted on the said screw spindle as a fulcrum and
adapted to screw itself up and down on the same, substantially as described.
2. In electric switches, the combination of a stationary screw spindle secured to
the base plate, with a switch lever mounted on the said screw spindle as a fulcrum
and adapted to screw itself up and down on the same, and one or more stationary
contact pieces adapted to form sliding contact by the axial motion of the switch
lever, substantially as described.
3. In an electric switch, the combination of a two armed switch lever A, and
stationary contacts, with a two armed auxiliary lever E adapted to act on the
switch lever during a part of its motion, and a double acting spring attached to the
auxiliary lever, said spring being adapted to accelerate the motion of the switch
lever and to retain it in position, substantially as described with reference to Figs. 1
to 3.
4. In an electric switch, the combination of a two-armed switch lever A¹ and
stationary contacts, with a double armed auxiliary lever E' adapted to act on the
switch lever during a part of its stroke, a double acting spring, attached at one end
to the main lever and at the other end to the auxiliary lever, and a handle adapted
to set in motion the auxiliary lever, substantially as described with reference
to Figs. 4, 4, and 5.
Dated this 24th day of August 1801
HENRY BARTON.
By Fairfax & Wetter,
433, Strand, London, Agents.