Vertically-opening section swtich having a rocking column

A high voltage section switch of the type includes a female current terminal situated at one end of a first vertical insulating column, a control blade which is hinged at one end of a second vertical insulating column and which carries at its first end a male contact intended to co-operate with the female contact, movement of the blade being provided by a mechanism connected to a rocking insulating column. The hinge between the blade and the second column is provided by means of two levers of different lengths.

FIELD OF THE INVENTION 
The present invention relates to a section switch particularly for high 
voltages, the switch being of the type comprising a female current 
terminal at one end of a first vertical insulating column and a blade 
hinged at one end of a second vertical insulating column, a first end of 
the blade carrying a male contact intended to cooperate with said female 
contact, movement of said blade being provided by a mechanism connected to 
a rocking insulating column. 
BACKGROUND OF THE INVENTION 
A section switch of this type is described in British patent number 306198. 
In the section switch described in that document, the mechanism comprises 
a first lever hinged both to said blade and to said rocking column, a 
second lever hinged both to said blade and to said second vertical 
insulating column, and a cam which is integral with said second vertical 
insulating column and which co-operates with a roller arranged at the 
second end of said blade. 
OBJECTS AND SUMMARY OF THE INVENTION 
A first aim of the invention is to provide a section switch of the type 
previously described but of simpler construction. 
The operation of the section switch described in the above-mentioned patent 
deteriorates considerably if ice forms on the cam or on the roller; the 
force exerted by the roller on the cam may be insufficient to break the 
ice so that movement of the blade is affected to the extent that it cannot 
close the section switch. 
The invention further provides a section switch, the operation of which is 
unaffected by the presence of any ice which may form either on the blade 
movement mechanism or on the contacts. 
The invention also provides a section switch utilizing thimble-type 
contacts which withstand short circuits better than jaw-type contacts. 
All these aims are met by the invention which provides a high voltage 
section switch of the type comprising a female current terminal situated 
at one end of a first vertical insulating column, a control blade which is 
hinged at one end of a second vertical insulating column and which carries 
at its first end a male contact intended to co-operate with said female 
contact, movement of said blade being provided by a mechanism connected to 
a rocking insulating column, wherein the hinge of the switch between said 
blade and said second column is provided by means of two levers of 
different lengths, each lever having a first end connected to a part 
integral with said second insulating column and a second end connected to 
a respective separate point on said blade, said mechanism which connects 
the rocking column and said blade being formed by an arm hinged at one end 
to said rocking column and at its other end to said blade, said female 
contact being constituted by a substantially horizontal tube which is 
longitudinally split over part of its length to form contact fingers, said 
female contact being protected by a hood provided with ice-breaking barbs, 
said male contact having an enlarged portion which can engage between said 
fingers, the length and relative arrangement of said levers being chosen 
to ensure that when the section switch is opened, the initial blade 
movement has a horizontal component tending to separate the male and 
female contacts as well as a component tending to bring the end of the 
blade down to a level below that which it occupies when the section switch 
is closed, said movement being followed by rotation of the blade about the 
end of the second insulating column.

DETAILED DESCRIPTION 
In the description which follows, only one pole will be described, it being 
understood that a section switch for a three-phase line will comprise 
three identical poles. 
Reference 1 in FIG. 1 designates a metal beam constituting the upper part 
of the frame of the section switch. This frame is not described in further 
detail as it is constructed in conventional manner and does not form part 
of the invention. 
Secured to frame 1 is a first vertical insulating column 2 which carries a 
protective cap 3 containing a female electrical contact 4, visible in 
detail in FIG. 2 and comprising a tube which is longitudinally split over 
part of its length to form contact fingers 4A arranged in a manner known 
as a thimble. This female contact is intended to co-operate with a male 
contact to be described later. A spring 4B ensures contact pressure. The 
cap 3 is open in the shape of a horn and includes ice-breaking barbs 4C 
and a drainer 4D. Contact 4 is connected to a first current terminal 5. 
Beam 1 also carries a second vertical insulating column 7 having a second 
current terminal 8. A vertical plate 9 with two hinge points 10 and 11 is 
secured to the top of column 7. Connected to the hinge point 10 is the 
first end of a first lever 12, the second end of which is hinged to one 
end 13A of a metal blade 13 whose other end carries a male contact 13B 
co-operating with the female contact 4. Connected to the hinge point 11 is 
the first end of a second lever 14, the other end of which is hinged to 
the blade 13 at a hinge point 15. When the section switch is in the closed 
position, the male contact is engaged in the female contact and electrical 
connection between the two terminals 5 and 8 is provided by the blade 13. 
The male contact 13B is constituted by a tube having an enlarged portion 
which ensures good contact pressure with the thimble contact. A metal 
braid 16 provides electrical connection between the terminal 8 and the 
blade 13. 
It can be seen that a first feature of the invention is the use of thimble 
contacts instead of the usual jaw type contacts; this has two advantages: 
firstly, the thimble contact withstands short circuits better; and 
secondly, ice has more difficulty in forming on the female contact since it 
is protected by the cap and since its opening is not upwardly directed. 
Movement of the blade is provided by a rocking insulating column in the 
form of an insulating part 20 of the same type as columns 2 and 7 and 
hinged at its lower end about a fixed horizontal axis 21. This column is 
provided with means (not shown) allowing it to perform rocking movements 
in a vertical plane, the amplitude of said movements not exceeding about 
20 degrees from the vertical. These means may comprise for example a rod 
secured to the bottom of the column 20 and associated with a driving 
mechanism which pulls on the rod. 
The top of column 20 carries a hinge 22 to which is hinged the first end of 
an arm 23, the other end 24 of which is hinged to the blade 13. 
The operation of the section switch is as follows: 
in the closed position, column 20 is inclined to its maximum extent and 
towards the left in FIG. 1; 
to open the section switch, the control mechanism is moved so as to cause 
the column 20 to rock towards the right of the figure. Referring to FIG. 
3, line 40 represents the displacement of the male contact during an 
opening operation of the section switch. Due to the nature of the 
connecting mechanism between the rocking column 20 and the blade 13, and 
in particular because the levers 12 and 14 are unequal in length, the end 
13A of blade 13 at first moves in a straight line along its axis in the 
direction tending to separate the contacts 4 and 13B, this movement being 
associated with a slight lowering of the blade. Subsequently, the blade 
pivots in a vertical plane so as to reach the position shown in FIG. 3 
which corresponds to the open position of the section switch, the blade 
then being vertical and ensuring a gap for electrical isolation between 
the contacts. 
The section switch is closed by carrying out the same movements in reverse. 
Downward movement of the male contact to a position below the horizontal, 
followed by upward movement as the male contact nears the female contact, 
allow any ice which may have formed on the male contact to be broken on 
encountering the barbs 4C located at the entrance of the female contact. 
The section switch of the invention is simple in construction and therefore 
less costly than prior art section switches. 
The possibility of using a thimble-type contact allows short circuits to be 
withstood better than with jaw-type contacts. 
Ice is less of a problem than in prior art section switches, because the 
contacts are engaged horizontally and a protective cap can be used. 
It is to be understood that a schematic description of the device has been 
given. In particular, levers 12 and 14, an arm 23, and the associated 
components pertinent to the operation of the present invention have been 
described. Clearly these elements may be duplicated and arranged on either 
side of the blade, suitably spaced so as to permit them to cross, in order 
to form a symmetrical and balanced assembly. 
The invention is suitable for section switches for high voltages, above 25 
kV.