[0001] This invention refers to a track and an electrical connector for constructing electrical
systems with track-type distribution.
[0002] It is a well-known fact that there are elements in the known technique for constructing
electrical systems with track-type distribution, that is to say systems in which one
or more tracks create lines of contact to which electrical devices are electrically
interconnected by inserting special connectors into the tracks. The track generally
has a substantially square U-shaped cross-section which forms a channel to receive
coupling members of the connectors. The bottom wall of the U constitutes a wall for
fastening the track, while running along one side wall inside the channel are electric
contact lines.
[0003] The coupling member of a connector comprises operating means which cause the lateral
protrusion from it of springs which make contact with the electric lines in the track,
and elements which mechanically fit into slots in the side walls of the track. The
mechanical coupling elements enable the casing of the connector to be used for hanging
electrical equipment such as spotlights directly from the track.
[0004] The direction of insertion of the connectors is always perpendicular to the fastening
surface of the track. This results in a relatively large volume of space taken up
by the track and the connector, which protrude considerably from the surface on which
the track is fastened. To limit the protrusion, the channel is relatively ample in
width, so as to obtain coupling members of sufficient mechanical sturdiness, despite
the limited depth of the channel. The width of the channel, however, facilitates the
introduction of foreign bodies and dust, with the risk of short circuits, electrocution,
and unreliable contact between connector and electric lines. Due to the risk of electrocution,
the tracks of known technique are not suitable for installing "within easy reach"
and are usually installed high up. This makes these tracks generally suitable only
for use in overhead lighting systems.
[0005] An additional problem, consisting of the generically square cross-section and the
need to leave the wide entrance to the channel open, makes the track difficult to
disguise in the environment.
[0006] Moreover, the coupling and uncoupling means are generally rotative elements which
are relatively difficult to operate.
[0007] The scope of this invention is to obviate the aforementioned problems by providing
an electrical track and connector assembly which offers greater flexibility and safety
in use, together with improved performance and reliability compared to the known devices.
[0008] This scope is achieved, according to the invention, by providing a track and an electrical
track (10) and a complementary connector (11) assembly for the distribution of electric
power in a track-type electrical system, the track comprising a generically U-shaped
outer casing which defines a channel (13) internally provided with electric contact
lines (17) and an entrance (14) on one side of the track to receive a coupling portion
(15) of the complementary connector (11), the coupling portion of the connector comprising
electric contact elements (18, 19, 20) for connection with the electric contact lines
(17) inside the channel, characterized by the fact that the external surface (12)
of one of the two arms of the U constitutes a side for fastening the track, the aperture
(14) of the channel opening out in a direction substantially parallel to the fastening
side (12).
[0009] The innovative principles of this invention and its advantages with respect to the
known technique will be more clearly evident from the following description of a possible
exemplificative embodiment applying such principles, with reference to the accompanying
drawings, in which:
- figure 1 shows a schematic, partially cutaway, rear perspective view of a track and
connector assembly made according to the invention;
- figure 2 shows a partially cutaway perspective view of a connector element of figure
1;
- figure 3 shows a cross-sectional view of an assembly of figure 1 in the assembled
condition;
- figure 4 shows a similar view to that of figure 3, but with the connector partially
extracted from the track;
- figure 5 shows a plan view, with parts further removed, of the connector of figure
2;
- figure 6 shows a view along the line VI-VI of figure 5, of a detail of the connector
in a first condition;
- figure 7 shows a view similar to that of figure 6, with the detail of the connector
in a second condition.
[0010] With reference to the figures, figure 1 shows a track 10 (for example an aluminium
extrusion) to which is coupled a connecting element 11 having a casing made of insulating
material. The track 10 has a generically U-shaped cross-section, with the arms greater
in length than their reciprocal distance (for example at least twice as long and,
advantageously, at least four times as long) to define an internal channel 13. The
aperture is also advantageously of such width as to prevent the introduction of a
finger through it.
[0011] The track has an external surface 12 of one of the two arms which constitutes a side
for fastening the track. The internal channel 13 has an aperture 14 which opens out
on the side of the track, that is to say in a direction parallel to the fastening
surface 12, to receive a coupling member 15 of the connector 11.
[0012] Disposed along an internal wall of the channel, (advantageously, the internal wall
of the arm of the U which externally forms the fastening surface 12) are insulating
housings 16 containing parallel electric wires or lines 17 whose bare lateral surface
enters into contact with flexible electric contact tangs 18, 19, 20 protruding from
the coupling member 15 through passageways 39, 40, 41.
[0013] Disposed on the leading edge (with reference to the direction of insertion in the
channel) of the coupling member 15 is a hooking element 21, which (as will be explained
further on) engages with an undercut 22 on the bottom of the channel 13.
[0014] Figures 3 and 4 show a connector 11 respectively in a condition completely coupled
to the track and in a condition of insertion or partial extraction.
[0015] Advantageously, the track is secured by its surface 12 to a fastening wall by means
of a structural section 23 having holes 24 for the passage of fastening screws 25.
[0016] As can be clearly seen in figure 3, in order to improve the mechanical sturdiness
of the connector-track assembly, the connector has a wing 26 protruding in the direction
of the coupling in the track, to define a housing for a tooth 27 opposingly protruding
from the structural section 23.
[0017] The connector 11 has an outer casing 28 which comprises a support 29 protruding from
the connector in a direction opposite to that of the fastening surface of the track.
[0018] Electrical equipment, such as spotlights or the like (not shown) can be fastened,
for example by means of screws, to the support 29. Alternatively, the support can
comprise a simple shank for the entrance of electric wires.
[0019] Figures 2 and 5 show a connector element 11 with the cover partially removed to reveal
the internal components. As can be seen in the figures, inside the outer casing 28,
the connector 11 comprises terminals 30 (preferably of the known quick-coupling spring
type) for connecting the stripped ends of electric cables with three conducting metal
strips 31, 32, 33.
[0020] The strip 33 has an opposing end 34 which forms an electric spring contact (not shown)
which protrudes permanently from the face of the coupling member 15 opposite the face
from which the contacts 18, 19, 20 look out, to form an earth connection between the
terminal of strip 33 and the metal structure of the track.
[0021] The strip 32 has an end opposite the terminal 30 shaped to form the electric spring
contact 18. The strip 31 splits into two arms 35, 36 which have a free end respectively
forming the electric spring contact 19 and the electric spring contact 20.
[0022] The electric spring contacts 18, 19, 20 are contained in a recess in the coupling
member through which slides a cursor 37, made of insulating material, which is made
to slide in the direction of the extension of the track by means of an operating end
38 protruding from the outer casing 28.
[0023] The cursor 37 has cams and countercams which induce or do not induce the contacts
to face out from their respective holes 39, 40, 41 depending upon the position of
the cursor along its stroke, so as to attain a position of inactivity or enablement
to extract the connector from the track, in which the contacts are all retracted in
the coupling member (figure 5), an intermediate position of extraction of the contact
18 and one of the two contacts 19 or 20 (figure 2), and a final position of extraction
of the contact 18 and the other of the two contacts 20 or 19 (figure 1).
[0024] Between the three positions, further positions can be provided in which the electric
spring contacts are retracted into the connector.
[0025] As can be clearly seen in figures 2 and 5, to achieve the movement of the spring
contacts, the cursor 37 has cams and countercams for each spring contact. Each spring
contact slides over the respective cams and countercams by means of sliding surfaces
protruding laterally from its base. In particular, the contact 18 has sliding surfaces
42, 43 sliding respectively over an upper countercam 44 and a lower cam 45; the contact
19 has sliding surfaces 46, 47 sliding respectively over an upper countercam 48 and
a lower cam 49; the contact 20 has sliding surfaces 50, 51 sliding respectively over
an upper countercam 52 and a lower cam 53.
[0026] The sliding of the cursor thus gives rise to the aforementioned movements of extraction
and retraction of the contacts from their respective holes in the coupling member
15.
[0027] Advantageously, the cursor comprises protective insulating surfaces 58, 59, 60, which
come to rest over the spring contacts 18, 19, 20 when the cursor is in the initial
position (figure 5) so as to close the passages 39, 40, 41 completely.
[0028] The movement of the cursor also controls means for enabling the coupling and uncoupling
of the connector from the track, so as to prevent the connector from being extracted
while the spring contacts are protruding from it to rest on the electric lines 17.
Likewise, the contacts are prevented from being extracted when the connector is not
plugged into the track.
[0029] The enabling means comprise a projection 54 which protrudes from the cursor 37 towards
the hooking element 21 (removed in figure 2 for the sake of clarity).
[0030] As can be seen in figure 7, the hooking element (which rotates on an axis 55 perpendicular
to the direction of introduction of the connector into the track) posteriorly comprises
a surface 57 which rests on the protrusion 54 and maintains the hooking element in
the hooking position shown in figures 3 and 7. As can be seen in figures 5 and 6,
the surface 57 is interrupted by a slot 56 into which the projection 54 can fit when
the cursor is in the initial position of figure 5.
[0031] Springs (not shown) tend to rotate the coupling element towards the position shown
in figures 4 and 6.
[0032] When the connector is out of the track, the cursor is in the initial position of
figure 5, referred to as the disconnected or released position. The springs maintain
the hooking element in its extended position as shown in figure 4, the projection
54 of the cursor being received in the slot 56.
[0033] In this situation, the passages 39, 40, 41 are closed by the protective surfaces
58, 59, 60 so as to prevent any accidental contact with the electric contacts 18,
19, 20. This is important when the connector is a connector supplying electric power
to the track and consequently when the contacts are connected to the electric power
supply mains by means of the cables connected to the terminals 30.
[0034] The connector is plugged into the track by simply inserting the coupling member 16
into the channel 13 as shown in figure 4, until the head of the hooking member 21
reaches the end 61 of the channel. The end 61 is curved so as to induce the hooking
element to rotate on its own axis 55 upon continuation of the movement of introducing
the connector into the tract. The rotation is aimed at shifting the hooking element
to its hooking position shown in figure 3, with a coupling tooth 62 engaged in the
undercut 22 of the track. At this moment the hooking element is still free to rotate
in the opposite direction to permit the re-extraction of the connector from the track.
[0035] In the completely inserted condition, when the cursor 37 is shifted from its initial
position the projection 54 interferes with the surface 57 of the hooking element and
the latter is prevented from rotating towards the released position. The connector
is consequently firmly coupled to the track. The cursor 37 can be shifted to one of
its various positions, so as to achieve the protrusion of the spring contacts according
to the desired combination among those permitted by the cams and countercams.
[0036] For example, in the case of a connector supplying power to the track, the cams can
be made in such a way that all the contacts can be extracted simultaneously, whereas
in the case of a connector drawing power from the track to supply external elements,
the contact 18 and one of the two contacts 19, 20 can be extracted so as to select
the desired power supply line in the track.
[0037] In order to re-extract the connector from the track, it is necessary to shift the
cursor back to its initial position, so as to retract the electric contacts 18, 19,
20 and shift the projection 54 back in line with the slot 56 in order to free the
movement of the hooking element.
[0038] At this point it is clear that the intended scopes have been achieved, by providing
a contact track and connectors for it, which make it possible to achieve track-type
electrical systems without the problems of the known technique.
[0039] In fact, thanks to its limited thickness, a track as described can be secured for
example to a wall to simulate a simple aesthetical structural section. At the same
time, the ample coupling surface for coupling the connectors makes the coupling extremely
sturdy and enables the connector to withstand the weight of quite heavy electrical
equipment.
[0040] The mechanical coupling and uncoupling device is sturdy and easy to operate, as is
the electric contact selector.
[0041] The limited width of the channel eliminates problems of accidental contact with the
internal electric wires and reduces the possibility of external polluting agents collecting
in the channel. To improve the protection of the channel, it can also be provided
along its entire length with a protection in the form of a pliable membrane, as shown,
by way of example, by reference 63 in figure 4. The protection is shifted to one side
when a connector is introduced into the channel.
[0042] The foregoing description of an embodiment applying the innovative principles of
this invention is obviously given by way of example in order to illustrate such innovative
principles and should not therefore be understood as a limitation to the sphere of
the invention claimed herein.
[0043] For example, the aesthetical shape of the track can vary, as can vary the shape of
the connector.
[0044] The cam selector for the contacts of the connector can be provided with different
cams to provide different contact possibilities. For example, whenever the connector
supplies power to the track, the cams can be shaped in such a way that all three electric
contact elements protrude simultaneously to supply power to the lines in the track.
1. Electrical track (10) and a complementary connector (11) assembly for the distribution
of electric power in a track-type electrical system, the track comprising a generically
U-shaped outer casing which defines a channel (13) internally provided with electric
contact lines (17) and an entrance (14) on one side of the track to receive a coupling
portion (15) of the complementary connector (11), the coupling portion of the connector
comprising electric contact elements (18, 19, 20) for connection with the electric
contact lines (17) inside the channel,
characterized by the fact that the external surface (12) of one of the two arms of
the U constitutes a side for fastening the track, the aperture (14) of the channel
opening out in a direction substantially parallel to the fastening side (12).
2. Assembly as claimed in claim 1, characterized by the fact that the depth of the channel
is greater than its width, advantageously at least twice its width.
3. Assembly as claimed in claim 1, characterized by the fact that the electric contact
lines (17) are disposed along an internal wall of the arms of the U.
4. Assembly as claimed in claim 3, characterized by the fact that said internal wall
is that of the arm of the U which constitutes a side (12) for fastening the track.
5. Assembly as claimed in claim 1, characterized by the fact that the connector has an
element (21) which hooks onto the track disposed on the leading end of the coupling
portion (15) of the connector to engage with an undercut (22) on the bottom of the
channel.
6. Assembly as claimed in claim 5, characterized by the fact that the hooking element
(21) rotates on an axis (55) parallel to the extension of the track, to slide along
the end (61) of the channel, which is made curved, and shift from an inactive position
substantially aligned with the direction of insertion of the connector in the channel
to a position in which it engages said undercut (22).
7. Assembly as claimed in claim 6, characterized by the fact that the connector comprises
controllable means (54) for blocking the rotation of the hooking element (21) from
the engaged position to the inactive position.
8. Assembly as claimed in claim 1, characterized by the fact that the connector comprises
control means (37) for moving the electric contact elements (18, 19, 20) between a
retracted or inactive position and a protruding position in which they make contact
with electric lines (17) in the track.
9. Assembly as claimed in claim 8, characterized by the fact that the control means comprise
a cursor (37) inside the connector, sliding in the direction of the extension of the
track when actuated by a manually operated end (38), the cursor having cam means (44,
45, 49, 51, 53) which press against the contact elements to shift them to and from
inactive and contact positions in a pre-established sequence.
10. Assembly as claimed in claim 9, characterized by the fact that in the contact position,
the contact elements (18, 19, 20) protrude from apertures (39, 40, 41) in the casing
of the connector, the cursor (37) comprising plugging surfaces (58, 59, 60) which
slidingly close such apertures when the cursor is in a first position or position
of complete retraction of all the contact elements.
11. Assembly as claimed in claims 7 and 9, characterized by the fact that the blocking
means comprise a projection (54) on the cursor which prevents the rotation of the
hooking element (21) when the cursor is not in an initial position or position of
complete retraction of all the contact elements.
12. Assembly as claimed in claim 1, characterized by the fact that the electric lines
(17) are three in number.
13. Assembly as claimed in claim 9, characterized by the fact that the contact elements
(18, 19, 20) are three in number, two contact elements (19, 20) being interconnected
and alternately movable into the contact position.
14. Track for the distribution of electric power comprising an outer casing generically
shaped in the form of a U to define a channel (13) internally provided with electric
contact lines (17) and an aperture (14) on one face of the track designed to receive
a coupling portion of a complementary connector, characterized by the fact that the
outer surface of one of the two arms of the U constitutes a side for fastening the
track, the aperture (14) of the channel opening out in a direction substantially parallel
to the fastening side (12).
15. Track as claimed in claim 14, characterized by the fact that the depth of the channel
is greater than its width, advantageously at least twice its width.