Year: 1896

page_text: Date of Application, 22nd Dec., 1896
Complete Soucification Loft 22nd Sent
1807
Accented 6th Nov
1907
слев
We, P. R. JACKSON & Co., LTD., and JOSEPH SLATER LEWIS, of Salford Rolling
Mills, Manchester, in the County of Lancaster, Engineers, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to switches and has for its object to improve the con-
struction of these devices as will be hereinafter set forth.
According to our invention in constructing a double pole switch for example
we provide a rectangular frame preferably of hard wood made in the form of a
window sash and adapted to slide in guides secured to a vertical base plate of any
suitable material. The said base plate must be of an insulating material or the
sash must slide in insulated guides. The said frame may if preferred be made of
metal and adapted to slide in insulating guides. Mounted on said frame are two
insulated plates which form the movable contacts of the switch. The fixed
contact pieces of the switch are secured in pairs to the base plate above mentioned
by any suitable means, and so arranged that in the uppermost position of the
sliding frame aforementioned the movable contact bars connect or bridge the
lewer pair and upper pair of fixed contacts respectively so that the circuit is
made and in the lowest position of the said frame the contact of each pair are
disconnected and the circuit broken.
When it is desired to construct a single pole switch one of the plates only is
provided on the frame and one pair of corresponding movable contacts.
The movement of the frame may be caused by any suitable electromagnetic or
mechanical device either automatic or not; we prefer, however, to employ a pivoted
lever having a spring catch similar to a signal lever for example said lever being
connected to a pivoted bellcrank, one arm of which can engage with a rod secured
to the sliding frame so that when the bellcrank is operated by the lever the frame
is moved up and down.
We preferably provide a spring preferably of spiral form which is compressed
when the frame is raised and which acts as a cushion when the said frame is
lowered and the circuit broken. We also provide a spring which is compressed
as the frame is lowered, and which enables us to break the circuit quickly. We
sometimes provide a loose connection between the lever and bellcrank, so that,
on releasing a catch or clamp the frame will fall and break the circuit without
moving the lever. In a further modification we provide for clamping the
movable contacts against the next contacts by a suitable device, and arrange that
when the clamping device is released the switch shall automatically open the
circuit. This clamp may be released by an automatic device operated by the
current flowing in the mains. We may further immerse the contacts in any
suitable liquid so that arcing at the contacts is prevented.
Our improved switch is very simple in construction and is suitable for use on
circuits intended for carrying large currents since the parts can be made very
massive. Moreover, a small space only is occupied by the switch. In general the

page_text: weight of the parts will ensure a quick break but this may be assisted if desired
by a spring as hereinabove mentioned or by other suitable devices.
We do not confine ourselves to the, construction in which the frame moves in a
vertical direction since the direction of motion will in general be immaterial and
vary with the position of the switchboard and the conditions of the particular use
for which the switch is designed.
The distance between the fixed and movable contacts when the switch is opened
depends only on the travel of the frame and this may be made as large as desirable
in order to diminish the liability of destructive arcs being formed at the time of
breaking.
The contacts may be of the multiple knife edge tyne if desired.
Improvements in Electric Switches.
We, P. R. JACKSON & Co., LTD., and JOSEPH SLATER LEWIS, of Salford Rolling
Mills, Manchester, in the County of Lancaster, 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 an improved construction of electric switch.
According to our invention the movable part of the switch consists of a
rectangular frame on which the movable contacts or bridge pieces are secured.
The said frame can be moved in guides and in one position thereof the movable
contacts connect the fixed terminals of the circuit in pairs while in another
position of the frame the pairs of terminals are disconnected and the circuit
broken.
In order that our invention may be clearly understood we will now describe
the same with reference to the accompanying drawings which illustrate by way
of example how it may be carried into practical effect.
Figure 1 is a side elevation of a double pole. double break switch constructed in
accordance with our invention.
Figure 2 is a front view of the sliding frame and switch terminals.
Figure 3 is a view similar to Figure 2 shewing a switch with terminals of the
multiple knife edge type.
Referring now to Figures 1 and 2 A is a rectangular frame preferably of hard wood
adapted to slide in guides B secured to a base plate C of any suitable material.
Mounted on the frame 'A are two insulated plates D D which form the movablo
contact or bridge pieces of the switch. E E1 and E2 E3 are the fixed contact
pieces of the switch which form 'terminals of the circuit, said terminals are
insulated from each other and, when the switch is open, from the movable
contacts or bridge pieces D D¹. This may be done by constructing the base
plate C of insulating material and the frame A also of insulating material said
frame may however he made of metal, in which case the guides B are preferably
arranged to insulate the frame from the base plate. The mechanism shown in
the drawing for moving the frame in its guides consists of the lever F pivoted
at F¹ and provided with a spring catch F of any suitable description, said lever
is pivotally connected to a block F which slides between a shoulder G and a
collar G¹ on a rod G2 attached to the frame A. Interposed between the block and
the shoulder G is a spring H and a second spring His interposed between said
block and the collar G¹.

page_text: In the position shown in the drawing the frame A is raised and the
terminals E E are connected by the bridge piece D, the terminals E Es being
connected by the bridge piece D. If now the lever E is operated, being moved in
the direction of the arrow the frame A will be caused to slide downwards in its
guides withdrawing the bridge pieces from their respective terminals and thereby
breaking the circuit. The spring H is compressed when the frame is raised and
the spring His compressed when the frame is lowered, these springs act as
cushions and owing to the sliding connection between the lever F and the rod G
the frame A will be started quickly in either direction. In the switch shown in
Figures 1 and 2 the bridge pieces D D are formed of two plates which enclose
the respective fixed contacts when the frame is raised. Other forms of contact
may be employed, for example in Figure 3 which illustrates the upper portion of
the frame the bridge piece D is provided with U-shaped laminated contacts d
which make connection with laminated knife edges e secured to the fixed
terminals E E¹.
When it is desired to construct a single pole switch one bridge piece only is
provided on the movable frame and one pair of corresponding fixed terminals.
The distance between the fixed and movable contacts when the switch is open.
depends only on the travel of the frame and this may be made as large as desirable
in order to diminish the liability of destructive arcs being formed at the time of
breaking the circuit. In general the weight of the parts will ensure a quick
break, this being assisted by the spring H herein above described.
We do not confine ourselves to the construction in which the frame A moves
in a vertical direction as the direction of motion is immaterial and will vary in
position of the switch board and the conditions of the particular use for which the
switch is designed. Furthermore the means for operating the switch may be
very considerably varied. We have found, however, the device shewn in Figure 1
of the drawing to be convenient in practice.
Our improved switch is very simple in construction and is suitable for use on
circuits intended for carrying very heavy currents. Although a small space only
is occupied by the switch the parts can be made very massive.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:
1. An electric switch in which the movable contacts are mounted on a
rectangular frame which is reciprocated in guides in order to make or break the
circuit.
2. A switch and actuating lever constructed and operating substantially as
described with reference to the accompanying drawings.
001
100%
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham,
Patent Agents for the Applicants.