[0001] The present invention relates to a socket-switch unit for electrically connecting
a load, connected to the socket, to an electrical-energy supply line, in a controllable
manner.
[0002] A socket-switch unit comprising a box-like container formed by two portions separable
from one another and containing a socket, a switch and possibly protection devices
is known. One of the two portions of the container, which is usually fixed to a vertical
wall, has an opening for the passage of a cable comprising end wires of a supply line.
The switch is mounted in one of the portions of the container and is operable from
the exterior through a suitable opening of the container. The input connectors of
the switch are connected to the line ends, possibly via protection devices such as
fuses or automatic circuit breakers, and the output connectors are connected to the
socket. Units of this type often have mechanical interlocking devices between the
switch and the socket to prevent a plug from being inserted in the socket or removed
from the socket when the switch is closed, and are used in difficult environmental
conditions in which it is nevertheless important to ensure maximum safety of operation,
for example, on building sites and in workshops.
[0003] Known socket-switch units are commonly produced in two versions, that is: a first
version in which the socket is mounted in the portion of the container which is normally
fixed to a vertical wall and is arranged in a manner such that the plug can be inserted
from below through a lower side of the container, and a second version in which the
socket is mounted in the other portion of the container, more precisely, on the side
opposite to that which is fixed to the wall, so that the plug can be inserted from
the front. In both versions, the switch and the socket are both mounted in the same
portion of the container. For greater clarity, the two versions are shown schematically
in Figures 1 and 2, in which the two portions of the container are indicated 10 and
12, the switch and the socket are indicated 13 and 14, respectively, the supply cable
extending through an opening 16 of the container is indicated 15, and a plug to be
inserted in the socket is indicated 17.
[0004] The need to provide two distinct structures for the two versions is clear and this
constitutes a disadvantage for production.
[0005] As can easily be noted, although the two versions perform exactly the same function,
they are differentiated in that, in one, the two electrical devices, that is, the
socket and the switch, are in the portion of the container in which the opening is
provided for the passage of the supply wires whereas, in the other, the two devices
are in the portion of the container which does not have an opening. The two versions
thus have different wiring; the first permits an easy electrical connection of the
supply wires to the input connectors of the switch, whereas the second requires a
considerable length of the supply wires for fixing to the connectors of the switch
and, if the two portions of the container are not articulated to one another, also
involves some difficulty in the wiring operations.
[0006] To prevent these disadvantages, according to the invention, the two electrical devices
are mounted in the portion which does not contain the opening for the supply wires
and a connector is provided, connected electrically between the switch and the end
wires of the line. This connector is formed by a first element mounted in the portion
which contains the opening, which has connectors for electrical connection to the
supply wires, and by a second element mounted in the other portion of the container
and connected to the input connectors of the switch.
[0007] The invention will be understood further from the following detailed description
of a non-limiting embodiment thereof, given with reference to the appended drawings,
in which:
Figures 1 and 2 show schematically two socket-switch units according to the prior
art,
Figure 3 shows, in perspective, two portions of a socket-switch unit according to
the invention, ready to be fitted together, and
Figures 4 and 5 are two views, that is, a front view and a lateral section, respectively,
of the unit of Figure 3 with the two portions joined together.
[0008] The socket-switch unit according to the embodiment shown in Figures 3 to 5, in which
elements identical or similar to those of Figures 1 and 2 are indicated by the same
reference numerals, comprises a box-like container in which a socket 14, a switch
13, a connector 20a, 20b and three automatic circuit breakers 21 are mounted.
[0009] The container is formed by a first shell 10 and by a second shell 12 which can be
fixed together by suitable, conventional, releasable fixing means, for example, screws
(not shown), so as to form a compartment for the electrical devices and the various
electrical interconnection means. The first shell 10, which is fixed to a vertical
wall by conventional means, not shown, has an opening 16 for the passage of a cable
15 containing the end wires of an electrical-energy supply line, for example, the
three wires of a three-phase alternating supply line. Instead of being an independent
element, as shown, the first shell 10 could form part of a more complex structure,
for example, of an electrical switchboard comprising other electrical devices.
[0010] The three automatic circuit breakers 21 are mounted in the first shell 10 by means
of a track 22. They have three input connectors 23 in the form of clamps to which
the three end wires of the line 15 are fixed, three output connectors 24, also in
the form of clamps, and a common operating lever 28.
[0011] A first connection element 20a, also mounted in the first shell 10 by fixing means,
not shown, has three clamps 25 and three clip contact elements 26, each electrically
connected to a respective clamp 25. Three electrical wires 27 are fixed between the
clamps 24 of the automatic circuit breakers 21 and the clamps 25 of the connection
element 20a and, when the automatic circuit breakers 21 are closed, electrically connect
the three ends of the supply cable 15 to the three clip contact elements 26.
[0012] The switch 13 is mounted in the second shell 12 by conventional fixing means, not
shown. It has three input connectors in the form of blade contact elements 30, three
output connectors in the form of clamps 31, and an operating member represented by
a lever 32 which is fixed to a pin 33 extending through the switch 13 and projects
from the front wall of the shell through a slot 38.
[0013] The blade contacts 30 together constitute a second connection element 20b complementary
with the first connection element 20a and formed integrally with the switch. However,
if necessary, a second connection element separate from the switch but electrically
connected to its input connectors by suitable conductors may be produced.
[0014] The socket 14 is also mounted in the second shell 12 by suitable fixing means and
is accessible from the lower side for the insertion of a plug. Each of three wires
34 is fixed, at one end, to a respective contact of the socket 14 and, at the other
end, to a respective clamp 31 of the switch 13.
[0015] The second shell 12 has, in its front wall, a window 35 which, when the two portions
of the container are fitted together, is disposed in the region of the operating member
28 of the automatic circuit breakers 21. The window 35 is accessible by the opening
of a door 36 which is joined to the remainder of the shell 12 by means of a pin 37.
[0016] Suitable mechanical interlocking means, of known type and therefore not shown, interconnect
the operating member 32 of the switch 13, the socket 14, and the door 36 in a manner
such that the insertion of a plug in the socket 14 or its removal therefrom is prevented
if the switch 13 is in the closure position, and in a manner such that the door 36
can be opened only with the switch 13 open. The presence of these interlocking means
is indicated symbolically in Figures 4 and 5 by chain lines which join the three elements
affected by this function.
[0017] To form a socket-switch unit with a socket accessible from the front wall, it suffices
to change the position of the socket 14. This involves purely a simple modification
of the second shell 12 (in addition to a modification of the interlocking means, if
such means are provided). No modification of the first shell 10 is required. By virtue
of the invention, the two versions of the socket-switch unit mentioned at the beginning
can be produced, in practice, from a single basic structure, with considerable advantages
for the producer and distributor of the product. It will also be noted that the wiring
problems of the prior art do not in fact arise because the electrical connections
can be provided separately in each shell; the electrical connection between the two
shells takes place automatically when the connection elements of the connector are
coupled with one another when the two shells are fixed together.
1. A socket-switch unit comprising:
a box-like container, formed by a first portion (10) and a second portion (12) separable
from one another and having an opening (16) in the first portion (10) for the passage
of end wires of an electrical-energy supply line (15),
a socket (14) mounted in the second portion (12) of the container and accessible from
outside the container for the insertion therein of a plug electrically connected to
a load to be supplied, and
a switch (13) mounted in the second portion (12) of the container, operable from outside
the container, and having input connectors for electrical connection to the end wires
of the line (15) and output connectors (31) electrically connected to the socket (14),
characterized in that it comprises a connector electrically connected between the
input connectors of the switch (13) and the end wires of the line (15) and formed
by a first connection element (20a) and a second connection element (20b) which are
separable and of which the first (20a) is mounted in the first portion (10) of the
container and has connectors (25) for electrical connection to the end wires of the
line (15) and the second (20b) is mounted in the second portion (12) of the container
and electrically connected to the input connectors of the switch (13).
2. A socket-switch unit according to Claim 1, in which the second connection element
(20b) of the connector is integral with the switch (13).
3. A socket-switch unit according to Claim 1 or Claim 2, comprising protection devices
(21) electrically interposed between the connector and the end wires of the line (15)
and having input connectors (23) for electrical connection to the end wires of the
line (15) and output connectors (24) connected to the connectors (25) of the first
connection element (20a).
4. A socket-switch unit according to any one of Claims 1 to 3, comprising mechanical
interlocking means between the socket (14) and the switch (13), preventing the insertion
of a plug in the socket or the removal of a plug from the socket if the switch (13)
is in the closure position.
5. A socket-switch unit according to Claim 4, in which the second portion (12) of the
container has a window (35) in the region of the protection devices (21), and in which
an openable door (36) is provided on the window (35) and comprises further mechanical
interlocking means between the switch (13) and the door (36), allowing the door to
be opened only with the switch open.