An outlet box for a cable duct arrangement

Abstract: Outlet box for a cable duct (1) comprising a case-like channel track (2) provided with an installation slot (6) opening into a cable space (4) of the channel track and having edges forming fastening edges (8) for outlet boxes (3), the outlet box comprising at least one gripping tongue (13) snapping under the fastening edge of the channel track. In order to fasten the outlet box unslideably in the channel track, the outlet box comprises tightening means (14, 15) for pressing the gripping tongue into firm engagement with the fastening edge.

Description: This invention relates to an outlet box for a cable duct comprising a case-like channel track forming at least one cable space for cables and conductors and having a front plate provided with an installation slot covered with a cover, the edges of the installation slot forming fastening edges for outlet boxes, whereby the outlet box comprises at least one gripping tongue snapping under the fastening edge of the channel track. It is known from the prior art to use a cable duct arrangement in apartments, offices, staircases and the like, the required cables and conductors for electricity, telephone, antenna, etc., being encased in a cable duct extending along a desired wall/desired walls. Only socket outlets and other outlets and connections mounted in the front plate of the cable duct for use at various points are outwardly visible. All conductors, outlet boxes and installation equipment are invisible within the case-like channel track. The outlet boxes are thereby attached to the fastening edges of the front plate of the channel track in such a way that the cover plates of the outlet boxes are positioned substantially flush with the cover of the installation slot. The outlet boxes may be installed side by side in contact with or spaced apart from each other. Openings possibly remaining between the boxes are covered with cover plates of suitable size. Today there is a tendency to avoid the use of screws and other such separate fastening means for fastening the outlet boxes to the fastening edges of the channel track and to use so-called snap fastening means. For this purpose the frame of the outlet box is provided at the manufacturing step with one or more gripping tongues or other similar flexible retainer for each fastening edge. When the frame is pressed in position into the installation slot, the retainer snaps under the corresponding fastening edge and prevents the box from falling away from the correct position. A disadvantage of this kind of snap fastening is, however, that it does not prevent the outlet box from moving in the longitudinal direction of the fastening edge. As a result of this, there exists a danger that the outlet boxes are pushed away from the correct position during the installation or slide by themselves downwards in a vertical portion of the cable duct. This makes the installation work and the position of the cover plates slower and more difficult. An object of the present invention is to provide an outlet box for a cable duct of the above noted kind which avoids the above-mentioned disadvantage of known outlet boxes and enables the outlet box to be locked unslideably in position in the channel track of the cable duct without any special fastening measures. According to the invention, there is provided outlet box for a cable duct comprising a case-like channel track forming at least one cable space for cables and conductors and having a front plate provided with an installation slot covered with a cover, the edges of the installation slot being provided by fastening flanges for outlet boxes, the outlet box comprising a frame encompassing an interior of the box, the frame having attachment means for attachment of an installation ring of a coupling assembly, the frame being provided with a supporting flange for engagement with a front surface of a said fastening flange, the frame including at least one gripping tongue which normally projects from said frame and which is resiliently displaceable inwardly, relative to the remainder of the frame, towards the interior of the box, to snap under a said fastening flange of such a channel track, when the frame is inserted in such a channel track through said installation slot, to spring outwardly again behind said fastening flange, characterised in that said tongue is also resiliently displaceable towards and away from said supporting flange and a clamping screw is provided extending through said supporting flange and into said gripping tongue for drawing the gripping tongue towards the supporting flange for clamping such fastening flange between the supporting flange and the gripping tongue. The invention is based on the idea that the gripping tongues are also utilised as means for locking the outlet box to the channel track in such a way that the outlet box is releasably prevented from sliding along the fastening edges of the channel track. In a preferred embodiment, the frame as two such gripping tongues on opposite sides of the frame, each said gripping tongue having a respective said clamping screw extending through said supporting flange and into the respective gripping tongue for drawing the gripping tongue towards the supporting flange for clamping such fastening flange between the supporting flange and the gripping tongue. Because the locking of the gripping tongues takes place automatically when fastening the installation ring and cover plate to the frame of the outlet box, the locking does not require any separate additional measures. In the following the invention will be described in greater detail with reference to the attached drawing, in which Figure 1 is a perspective view of a cable duct arrangement in which outlet boxes according to the invention are used; Figure 2 is an enlarged view of the cable duct and one embodiment of an outlet box according to the invention when disassembled; and Figures 3 and 4 are a side view and an axial sectional view of the outlet box, respectively. A cable duct 1 shown in the drawing comprises a metallic, case-like channel track 2 having a substantially rectangular cross-section; and a number of outlet boxes 3. The channel track comprises a cable space 4 and an installation slot 6 in a front plate 5, the installation slot being covered with an openable cover 7. Both longitudinal edges of the installation slot are formed as fastening edges 8 for the outlet boxes. The outlet box 3 comprises a frame 9 to be attached to the channel track and a coupling assembly 10 provided with a supporting installation ring 11. A cover plate 12 is attached to the frame. The frame is provided on its opposite sides with flexible gripping tongues 13 which snap under the fastening edges when the frame is pressed in place in the installation slot and prevent the frame from moving out of the installation slot. In the embodiment shown in Figures 3 and 4, the gripping tongues are formed in the frame in such a way that they are both radially and axially flexible with respect to the frame. For this purpose, the gripping tongues are notched up to the bottom of the frame. The gripping tongue is provided with a threaded boring 14 for a screw 15 required for fastening the installation ring to the frame. In order to install the outlet box in the channel track, the frame 9 is first pressed in position in the installation slot of the channel track in such a way that supporting edges 16 positioned on opposite sides of the frame are pressed against the fastening edges 8 of the channel track, and the gripping tongues 13 snap under the supporting edges. After the connection of the conductors is completed, the coupling assembly 10 including an installation ring 11 is inserted into the frame and its fastening screws 15 are screwed in. When the screws are tightened, they draw the gripping tongues flexibly towards the installation ring, so that the fastening edges 8 of the channel track are clamped between the supporting edges and the gripping tongues of the frame. The drawing and the description related to it are only intended to illustrate the idea of the invention. In its details, the outlet box of the invention may vary within the scope of the claims. Even though the frame of an outlet box is normally provided with two gripping tongues positioned on opposite sides of the frame, one of the gripping tongues may be replaced with fixed fingers which are passed under one fastening edge of the channel track before the other gripping tongue snaps under the other fastening edge. The features disclosed in the foregoing description, in the following claims and/or in the accompanying drawings may, both separately and in any combination thereof, be material for realising the invention in diverse forms thereof.

Claims: Outlet box for a cable duct (1) comprising a case-like channel track (2) forming at least one cable space (4) for cables and conductors and having a front plate (5) provided with an installation slot (6) covered with a cover (7), the edges of the installation slot being provided by fastening flanges (8) for outlet boxes (3), the outlet box comprising a frame (9) encompassing an interior of the box, the frame having attachment means for attachment of an installation ring of a coupling assembly, the frame (9) being provided with a supporting flange (16) for engagement with a front surface of a said fastening flange (8), the frame (9) including at least one gripping tongue (13) which normally projects from said frame and which is resiliently displaceable inwardly, relative to the remainder of the frame, towards the interior of the box, to snap under a said fastening flange (8) of such a channel track, when the frame is inserted in such a channel track through said installation slot, to spring outwardly again behind said fastening flange, characterised in that said tongue (13) is also resiliently displaceable towards and away from said supporting flange (16) and a clamping screw (15) is provided extending through said supporting flange (16) and into said gripping tongue (13) for drawing the gripping tongue towards the supporting flange (16) for clamping such fastening flange between the supporting flange and the gripping tongue (13). An outlet box according to claim 1 wherein the frame has two such gripping tongues (13) on opposite sides of the frame, each said gripping tongue having a respective said clamping screw (15) extending through said supporting flange and into the respective gripping tongue (13) for drawing the gripping tongue towards the supporting flange (16) for clamping such fastening flange between the supporting flange and the gripping tongue (13). An outlet box according to claim 1 or claim 2 in combination with a coupling assembly including a portion adapted to be received within the box and further including an installation ring, said screw or screws also passing through said installation ring and serving to attach the installation ring to the frame (9). An outlet box according to claim 2 or claim 3 in which the surfaces of the gripping tongues which engage said fastening flanges (8) when the outlet box is fully installed in the cable duct are obliquely inclined relative to the opposing surface of said supporting flange.

Inventors: NISKANEN AIMO, NISKANEN, AIMO
Applicants: NOKIA ALUMIINI OY
Application year: 1991
Main classification: H01R13
IPC codes: H02G3