Improvements in Switches for Opening and Closing Electrical Circuits.
Year: 1889

page_text: Date of Application, 5th Sept., 1889
Complete Specification Left, 5th July, 1890-Accepted, 16th Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in Switches for Opening and Closing Electrical
Circuits.
I, ALFRED LYSTER SHEPARD, of 8 West Kensington Gardens, in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention to be
as follows:
My invention relates to that class of apparatus usually known as switches,
which are employed for opening and closing electrical circuits, and is designed to
overcome the objectionable sparking and liability to form imperfect contacts,
which are found in such devices as heretofore constructed. By my said improve-
ments I provide a switch which ensures the circuit being always either fully open
or completely closed, and secures a perfect contact between the fixed and movable
portions which serve to convey the current, thereby preventing the formation of
ares at the point of such contact and consequent damage to or destruction of the
apparatus.
In carrying my invention into practice I provide a base plate of mahogany,
slate or other suitable non-conducting material, to which the parts connected with
my improved switch are attached. Two flat pieces of brass or other metal, one of
which is preferably somewhat longer than the other, are laid on this base plate
and each is secured thereto by a suitable pin or stud passing through a hole
situated a short distance from one end thereof which pin or stud serves as a centre
round which the brass piece may turn. The two brass pieces or strips are thus
divided each by its own centre pin into two unequal portions or arms.
The
shorter arms are preferably of equal or approximately equal length and the two
centre pins or studs are placed at a distance apart. less than the combined length
of the said shorter arms, one of which is recessed to receive a corresponding
projection on the other, so forming a kind of knuckle joint by which the two brass
strips become interlocked and the act of moving one on its centre also moves the
other but in a contrary direction thereto. Thus by moving one strip in a positive
direction the other will be moved in a negative direction. Any other suitable joint
besides the knuckle joint described may be used as 1 do not confine myself to any
particular form.
Two brass pillars or other suitable stops are provided which limit the range of
motion of the longer brass strip. preferably allowing it to move an equal distance on
each side of the line passing through the centre pins or studs. A lateral projection
is provided on each side of the longer brass strip, or a cross piece of brass is attached
thereto, the ends of which projections or cross-piece are turned up to form catches
against which a projection on an operating lever is adapted to engage and thereby
move the said brass strip. This operating lever is preferably carried above the
aforesaid flat strips by a stud or short spindle passing through a bridge piece or
bracket, the other end of which short spindle carries the handle for moving the
operating lever. the said handle being situated above while the operating lever is
below the bridge piece or bracket. A comparatively strong spiral spring is fixed
hetween a projection on the end of the shorter of the two brass strips and a
corresponding projection on the underside of the operating lever tending to draw
these parts together.
The path of the current in my improved switch is preferably from the centre
pin or stud of the longer brass strip, along the latter to one of the aforesaid stops.
which stop must in this case he composed of metal, the positive and negative wires
being connected to the said stop and the centre pin or stud, one wire to each.
In some cases, however I provide two clips or stops one connected to the positive

page_text: and the other to the negative wires with which stops the longer brass piece makes
contact simultaneously. I thus obviate the disadvantage of having any movable
joints to convey the currents.
It is obvious that various modifications may be introduced into the improved
switch herein before described without departing from the nature of my invention.
Dated this 5th day of September 1889.
HASELTINE, LAKE & Co.,
45. Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in Switches for Opening and Closing Electrical
Circuits.
I, ALFRED LYSTER SHEPARD, of 8 West Kensington Gardens, in the County of
Middlesex, Electrical Engineer. 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:-
My invention relates to switches for opening and closing electrical circuits and
more especially to switches of that kind or class wherein the movable contact piece is
operated partly by hand and partly by means of a spring or the like.
Switches of this kind or class as hitherto constructed are objectionable owing to the
possibility of the said movable contact piece being moved slight distances from the
fixed contact or contacts thus causing sparking.
Attempts have been made to obviate this objection by so arranging the said movable
contact that it is operated by the action of a spring in which energy is stored by
means of a suitable handle. This arrangement has also been found defective owing
to the liability to form imperfect contacts.
My said invention is designed to overcome these objections and to provide a switch
that will ensure the circuit being always either fully open or completely closed, and
secures moveover a perfect electrical connection between the fixed or stationary and
the movable contacts which serve to convey the current, thereby preventing the
formation of ares at the point of such contact and consequent damage to or destruction
of the apparatus.
In the accompanying drawing I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure is a plan illustrating an electric switch constructed according to my
said invention the cover or casing being removed.
Figure 2 a similar view to Figure 1 showing the parts in a different position.
Like letters indicate corresponding parts throughout these two figures.
A is a circular or other suitably shaped plate of mahogany, slate or other suitable
non-conducting material. A is a tongue or contact clip and A2 is a strip or piece
'formed of brass or other good conductor of electricity and secured to the plate A.
The clip or piece A¹ is bent or curved so as to leave a clearance between a portion
thereof and the plate A and is so arranged as to be in close proximity to but not
actually in contact with the piece A². The said pieces A¹ A form the fixed or
stationary contact pieces. AA are the electric wires or cables. B, B are two
flat or other pieces, strips, or levers of brass or other suitable material, one of which
forms the movable contact and is preferably somewhat longer than the other. Each
of these strips or levers is pivoted at C to the base plate A by means of a suitable pin.
stud or the like. The short arms of the said levers B B are jointed or connected
together as indicated at B2 so as to form a kind of knuckle joint, or the said levers
are connected together in any other suitable manner. DD are stops which serve to
limit the range of motion of the levers B B'.
E is a cross piece firmly secured to or formed on the movable contact piece or
lever B and provided with projections E. F is an arm or lever secured to the stem
or spindle F of a handle F2. "The said stem or spindle F¹ is supported in a suitable

page_text: bearing in a bracket G firmly secured to the plate A.
is a stud or projection
provided at or near the extremity of the arm or lever F and adapted to engage with
one or other of the projections E', when the said arm or lever F is moved by the
handle and thereby move the said movable contact or lever B in one or the other
direction. H is a spiral spring one extremity of which is secured at H' to the free
extremity of the lever B and the other extremity of which is secured at H² to the
arm or lever F about midway between the extremities thereof, or in any other suitable
position thereon.
The movable contact piece or lever B is shown in Figure 1 of the drawing in
electrical connection with the fixed or stationary contact pieces A' and A² and the
circuit completed thereby, and in Figure 2 moved out of electrical connection with
the fixed or stationary contact A' and the said circuit broken or interrupted.
The electric wires or cables A are connected to the said fixed on stationary contact
pieces A A. and when the movable contact piece B is in such a position as to form
electrical connection between the fixed or stationary contact pieces, the electric
circuit will be completed through the said fixed or stationary contact piece A¹
movable contact piece or lever B and the fixed or stationary contact piece A² or
vice versa.
The operation of the apparatus is as follows, that is to say. In order to shift or
throw the movable contact piece or lever Bout of electrical connection with the
fixed or stationary contact piece A¹ the handle F2 is turned until the pin, stud or
projection F on the operating arm or lover F comes into contact with the other or
opposite projection E on the cross bar or cross piece E. The spring H is at the
same time moved to the other side of its pivot point or dead centre or into such a
position that it will act upon the free extremity of the lever B' so as to pull it in the
opposite direction thereby through the joint B suddenly shifting or moving the
movable contact piece B away from the fixed or stationary contact piece A¹ and
against the stop D into the position shown in Figure 2. Should the movable contact
piece B be so firmly wedged underneath the fixed or stationary contact piece Al as
not to yield to the strength of the said spring H, the preliminary or initial movement
thereof is assisted by hand by continuing to turn the handle 2 When the movable
contact piece B is sufficiently disengaged the spring H comes into operation and
completes the movement.
For throwing or moving the said movable contact piece B into electrical connection
with the fixed or stationary contact piece A' the handle is turned in the opposite
direction and the operating lever F and spring H moved or adjusted thereby so as
to act upon the lever B and move it in the contrary direction or the direction to
make contact.
In case the strength of the said spring is insufficient to form proper electrical
connection between the movable contact piece B and the fixed or stationary contact
piece A the turning of the handle F2 is preferably continued so as to more forcibly
complete the said electrical connection, by means of the arm or lever T stud or
projection F and projection E on the cross piece E.
Although I have herein before described a convenient and advantageous method of
carrying my said invention into practice it is obvious that I can somewhat modify the
construction of my improved electric switch without departing in any way from the
nature of my said invention. For instance I sometimes dispense with the fixed or
stationary contact piece A and so arrange the apparatus that the current enters or
In some
leaves the switch by the pivot pin or stud of the lever B or otherwise.
instances I bend or curve the herein before mentioned movable contact piece, and
arrange the said fixed or stationary contact piece or pieces upon a raised portion of
the base plate of the switch. In this case the handle is fitted upon a suitable spindle
having a crank or lever to which is connected one extremity of the hereinbefore
mentioned spring. The said handle is so arranged that it can be turned a certain
distance in either direction before operating the said spindle. The herein before
mentioned cross piece and projections being dispensed with, I sometimes provide the
said bent or curved movable contact piece with a rearward or other extension adapted

page_text: to simultaneously form or make contact, or electrical connection with another fixed
or stationary contact piece. or contact pieces. Instead of the spiral spring herein-
before described I sometimes employ a flat or other suitable spring.
I sometimes pivot the movable contact piece upon the spindle of the operating
handle, which latter is in this case firmly secured to the said spindle. The operating
crank or lever upon the extremity of the said spindle is placed beneath the movable
contact piece and is arranged to engage with suitable projections upon a cross bar or
cross piece as herein before described. The spiral or other spring connecting the said
operating crank or lever to the free extremity of the short pivoted lever is placed
beneath the mechanism.
I sometimes so arrange my improved electric switch that it can be operated by
pulling and pushing the operating handle. In this case I may advantageously
duplicate the mechanism.
This herein before mentioned spring may be arranged so as to be operated under
compression instead of under tension.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I wish it understood that I
claim,
21
First. In a switch for opening or closing electrical circuits the means for preventing
sparking and ensuring good electrical contact comprising pivoted movable contact
piece or lever a pivoted lever jointed thereto, and a suitable spring connected at
one extremity to the said lever and at the other to an operating arm or lever upon
the stem of the operating handle substantially as and for the purposes set forth.
Second. In a switch for opening or closing electrical circuits the combination of a
pivoted movable contact piece or lever, a pivoted lever jointed thereto, and connected
by means of a suitable spring to an operating arm or lever upon the stem of the
operating handle, and suitable means for permitting a certain amount of movement
of the said operating lever relatively to the movable contact piece, and previous to
engaging therewith, substantially as specified.
Third. An improved switch for opening or closing electrical circuits comprising
a suitable base plate, cover or easing, one or more fixed or stationary contact pieces,
a pivoted movable contact piece or lever, a pivoted lever jointed thereto, a spring
secured at one extremity to the latter and at the other to an operating arm or lever
upon the stem of the operating handle, and a cross bar or cross piece upon the said
movable contact piece having suitable projections with one or other of which is
adapted to engage a pin, stud or projection upon the operating lever substantially as
described.
Fourth. The modification of my improved switch for opening and closing
electrical circuits wherein I bend or curve the movable contact piece, substantially as
described.
Fifth. The modification of my improved switch for opening and closing electrical
circuits wherein I pivot the movable contact piece to the spindle of the operating
handle, substantially as described.
Sixth. The improved switch for opening or closing electrical circuits constructed
substantially as described with reference to the accompanying drawing and operating
as, and for the purposes set forth.
1000
ALFRED LYSTER SHEPARD.
Haseltine, Lake & Co.,
45. Southampton Buildings, London, Agents for the Applicant.