[0001] The subject of the present invention is an electrical device for sectional structures
to be mounted on walls, comprising an active element associated with a body housing
means for the electrical connection of the device, the body comprising a front portion
in which the active element is situated so as to be accessible from outside when the
structure is mounted on the wall, coupled to a rear portion in which the electrical
connection means are disposed and which has openings for the passage of conductors.
[0002] For greater clarity, it is appropriate to indicate that the term electrical device
used in this description and in the following claims should be understood, in a generally
accepted meaning, as defining those components of electrical installations for public
buildings and the like which are usually fitted on the walls of rooms; various devices
such as light switches, electrical sockets, bells, controls and knobs for operating
various devices such as thermostatic regulators or timers, light and/or sound indicators,
fuses, connections for radio or television aerials and anything else which may be
used in the installations considered above thus fall within this definition.
[0003] As is known, nowadays, most of the devices just mentioned are fitted in corresponding
sectional structures of the type mentioned above; this sectional arrangement is in
fact intended to give the structures a modular character, that is, to permit interchangeable
use of various parts which make up the structure in order to satisfy the various requirements
of use; for example, it is possible to have structures which can house a single device
or a plurality of devices of different kinds without the need, however, to produce
cover plates, support frames and other suitable structural parts for the various devices.
In general, these sectional structures give rise to a series of coordinated products
with considerable economy and rationalization as regards the production and commercial
aspects.
[0004] More specifically, the electrical devices in question are fitted in seats in the
support frames of the sectional structures and they are fitted by means of a snap-engagement
by virtue of which the devices can then be removed, possibly with a pointed tool such
as a screwdriver or the like, in order to be replaced.
[0005] The electrical devices are constituted essentially by hollow bodies of electrically
insulating material, for example, plastics or the like, inside which the various electrical
components of the device such as the contacts and terminals are housed, as will be
described further below; the body is usually formed by two portions joined together
in a box-like configuration.
[0006] A first portion is disposed at the front facing an operator when the device is mounted,
together with its structure, on a wall and the active element of the device, that
is, the lever of a switch, the push-button of a bell or the knob of a thermostatic
regulator, etc., according to the type of device fitted, is disposed therein; this
active element is accessible from outside the body of the device and is also on the
front of the structure mounted on the wall.
[0007] The rear portion of the body of the device, however, is represented by a base in
which the terminals for electrical connection to the current-conducting wires provided
in the wall in a position behind the device are disposed; the rear portion of the
body therefore has holes through which the aforementioned wires can extend towards
its interior.
[0008] A fairly important practical aspect which is known to operators and concerns the
good operation of the devices consists of their correct electrical connection to the
current-conducting wires.
[0009] For this purpose, there are currently precise standards for the safety of electrical
devices which impose considerable constraints on their structure and which are also
intended to ensure their correct electrical connection; for example, the connection
terminals must be accessible from outside by means of suitable holes provided in the
body of the device, some of which are intended for the passage of the ends of conductor
wires which are left uncovered by their protective sheath, whereas others serve for
the insertion of screws for clamping these ends in the terminals. The distances between
the terminals and between the holes and the dimensions of these elements in general
are subject to precise limitations to prevent the formation of harmful electric arcs
when the device is in operation as well as to prevent connections with incorrect polarity,
particularly when there are more than two terminals.
[0010] In general, it can be confirmed that, although, on the one hand, the limitations
provided for by the abovementioned standards afford the electrical devices the necessary
safety, on the other hand, they do not facilitate the work of the operators who have
to handle these devices for any reason, for example, for repair or maintenance operations
on the electrical installations.
[0011] In this connection, it should be pointed out that, currently, it is not possible
to check the electrical connection of devices from outside the body without the need
either to disassemble the connection temporarily or to use a suitable instrument (for
example a tester); in both cases, various contingent situations which may arise in
practice may cause inconvenience, for example, when a device the connection of which
is to be checked is difficult to reach because it is positioned at a point which is
not easily accessible, or when there is not sufficient space to be able to use a tester.
[0012] The object of the present invention is to provide an electrical device such as that
considered at the beginning which has structural and operational characteristics such
as to prevent the problems set out in relation to the prior art.
[0013] This object is achieved by a device defined in the claims which follow this description.
[0014] For a better understanding of further characteristics and the advantages achieved
by the invention, a description of an embodiment thereof is given below by way of
nonlimiting example, with the aid of the appended drawings.
[0015] In the latter, Figure 1 is an axonometric view of a device according to the invention,
with parts disconnected, and Figures 2 and 3 are a side view and a rear view of the
device of Figure 1, respectively, in an assembled condition.
[0016] In the aforementioned drawings, the device according to the invention is generally
indicated 1 and is constituted by a normal light switch intended for a sectional structure,
shown in broken outline in Figure 1.
[0017] The device has a hollow body 2 formed by a front portion 2a and a rear portion 2b
coupled with one another in a box-like configuration; the front portion 2a is in front
of the rear portion 2b when the device is fitted in the structure on a wall and has
an opening 3 in which the active element 4 of the device, in this case constituted
by the lever of the switch, is disposed.
[0018] The rear portion 2b of the body is made of transparent material which affords visual
access to the interior of the body 2; more particularly, in the transparent rear portion
2b, there are terminals 6 for the electrical connection of the device and, in a position
beside these, the rear portion 2b has a series of holes 8, 9 and 10. These represent
respective holes for the passage of the ends (not shown in the drawings) of conductor
wires (holes 8a, 9a, 10a) and of screws (holes 8b, 9b, l0b) for clamping these ends
in the terminals; in a preferred embodiment, these holes are formed in projections
11 and 12 disposed on the rear of the body and having profiles matching those of the
terminals. This provides a better view of the terminals from outside the body.
[0019] It can be understood from the foregoing description that the device of the invention
achieves the object mentioned above.
[0020] In fact, it is clear that, by virtue of its transparency, the rear portion 2b of
the box-like body of the device enables an operator to make a direct visual check
of the electrical elements housed in the body; this enables the state of the electrical
connection of the device to be checked at any time.
[0021] Moreover, this check is made more effective simply by the fact that the terminals
and the other components of the device inside the body can be illuminated from outside.
[0022] Finally, it should be underlined that the results referred to above are achieved
without reducing the safety features of the device.
[0023] In fact, by virtue of the use of the transparent material to form the rear portion
of the housing body, it has not been necessary to introduce structural alterations
to the body of the device such as, for example, slots, grooves or the like, nor was
it necessary to change the shape or size of the holes 8, 9, 10 which detail could
have adverse effects as far as the prevailing standards are concerned.
[0024] Moreover, it hardly needs to be pointed out that plastics materials with electrically
insulating properties such that the devices conform perfectly to the safety standards
required for electrical applications, can be used to form the rear portion of the
transparent body.
[0025] Finally, it should not be overlooked that the visual access to the interior of the
devices also enables checks to be carried out at the production stage in order to
check for any defects in the items produced.
1. An electrical device for sectional structures to be mounted on walls, comprising
an active element (4) associated with a body (2) housing means (6) for the electrical
connection of the device, the body comprising a front portion (2a) in which the active
element (4) is situated so as to be accessible from outside when the structure is
mounted on the wall, coupled to a rear portion (2b) in which the connection means
already mentioned are disposed and which has holes (8a, 9a, 10a) for the passage of
conductors, characterized in that the rear portion of the body is made of transparent
material.
3. A device according to Claim 1, characterized in that the transparent material of
the rear portion is an electrically insulating, plastics material.
3. A device according to any either of Claims 1 and 2, characterized in that the connection
means comprise terminals and that the rear portion is of a shape matching that of
the terminals.
4. A device according to Claim 3, characterized in that the holes (8a, 9a, 10a) are
formed in corresponding projections (11, 12) of the rear portion (2b) of the body
of the device.