MODULAR CONTACT AND/OR SIGNALLING DEVICE FOR ELECTRICAL PANELS
The present invention relates to a modular contact and/or signalling device for electrical panels in accordance with the introduction to the main claim.
More particularly, it relates to a modular contact and/or signalling device for electrical panels for use in the automation sector, mainly in elevator systems. Modular contact and/or signalling devices for electrical panels are well known in the state of the art. They comprise essentially a support casing housing a pair of conductor elements suitably fixed therein.
These conductor elements face each other, with each presenting a flattened part. A slider, also of conducting material, is movable against a spring, and can assume two positions, a first in which the slider electrically connects together the two conductor elements by resting on the flattened part of the conductor elements, and a second in which the slider is not in contact with either of said elements.
Hence when the slider rests on the conductor elements, they are short- circuited. The end of a bent flat spring element is also fixed on each of said conductor elements. This spring element communicates with the outside.
An end part of the spring element presents a cavity, this cavity engaging on a projection on the conductor element, downstream of the fixing point. The flat spring hence remains under tension, engaged on the projection on the conductor element. The support casing presents two passageways. A first, bounded laterally by a rigid wall, directly faces the flat spring, while the second faces the projection on the conductor element. By inserting a pointed tool (for example a screwdriver) into the first passageway between the rigid wall and the flat spring, this latter is
elastically compressed to detach it from the projection on the conductor element and cause the flat spring cavity to slide onto the projection thereon.
This flat spring cavity then faces the second passageway.
By inserting an electric wire or cable through said second passageway, specifically into the cavity of the flat spring, and then extracting the pointed tool from the first passageway, the spring returns elastically to trap the electric cable in said spring cavity, against the projection on the conductor element.
The electric wire hence remains properly fixed to the conductor element without the need for conventional screw clips. However these systems suffer from a serious drawback which rises in practice when modular contact devices connected in parallel have to be installed and maintained.
In such a situation, at least two electric wires housed simultaneously in the flat spring cavity are electrically connected to each modular device, and specifically to each conductor element.
When just one of these wires is to be disconnected, the flat spring has to be flexed. This releases both wires trapped between the spring and the projection on the conductor element. This is extremely bothersome and results in considerable time loss. An object of the present invention is therefore to provide a modular contact and/or signalling device for electrical panels which represents an improvement on the known art.
A further object of the invention is to provide a modular contact and/or signalling device for electrical panels which enables cables even connected to the same conductor element to be trapped or released independently, without having to disconnect both of them, whenever just one of them needs to be disconnected.
These and further objects are attained by a modular contact and/or signalling
device for electrical panels in accordance with the technical teachings of the accompanying claims.
Further characteristics and advantages of the invention will be apparent from the description of a preferred but non-exclusive embodiment of the modular contact and/or signalling device for electrical panels, illustrated by way of non- limiting example in the accompanying drawing, in which:
Figure 1 is a perspective view of a modular contact and/or signalling device for electrical panels according to the present invention;
Figure 2 is a view thereof from below; Figure 2B is a view of an enlarged detail of Figure 2;
Figure 3 is a side view of the device of Figure 1 ;
Figure 4 is an exploded perspective view of the device of Figure 1 ;
Figure 5 is a front view of the device of Figure 1 , without its cover;
Figure 6 is a detailed perspective view of a conductor element of the device of Figure 1 ;
Figure 7 is a view similar to that of Figure 5, but reduced, showing a different embodiment of the device of the present invention;
Figure 8 is a perspective view of a conductor element of the device of Figure 7; and Figure 9 is an exploded perspective view of the components of the device of
Figure 9.
Said figures show a modular contact and/or signalling device for electrical panels, indicated overall by 1.
It comprises substantially a support casing 2 symmetrical about an axis a (Figure 3) and presenting a pair of seats 3 in which a pair of conductor elements 8 are housed, suitably secured by supports 5, 7, 11 and protuberances 4, 5, 6.
The conductor elements 8 are disposed in known manner within the support
casing 2, symmetrical about the axis a and facing each other. Each presents a flat surface 10 provided on a bent part 9 of the conductor element. The surface 10 is a resting surface for a plate 13 which, when resting on the surface 10, substantially short-circuits the two conductor elements 8 within the support casing 2.
The plate 13, vertically movable against a spring 14, is guided by the walls 16a, 16b of a first component 16 of a slider 15. The first component 16 is snap-fitted to a second component 17 of said slider, the spring 14 being present between said second component and said plate. The slider 15, formed by the two components and the plate 13, is slidable within the support casing 2 and guided by it in known manner, against the action of the spring 18. The slider 15 can assume substantially two positions,: a first, visible in Figure 5, in which the plate 13 short-circuits the two conductor elements 8, to close the circuit, and a second in which the plate 13 is detached from the element 8, to open the circuit. The end 19a of a bent flat spring element 19 is fixed onto each conductor element 8 at the end distant from the bent end 9. A pair of profiled elastic blades 20, 21 , each comprising a cavity 22 of rectangular plan, branch from the end 19a of the flat spring element 19. These cavities 22 engage projections 23 of the conductor element 8 which branch therefrom downstream of the fixing point between the conductor element 8 and the end 19a. The profiled elastic blades 20, 21 are therefore under tension and substantially engaged by and resting against said projections 23 on the conductor element 8, these projections 23 helping to guide the movement of said blades 20, 21 as described hereinafter. For each conductor element 8 the support casing 2 presents two first passageways 24, 25 facing the blades 20, 21 of each conductor element 8, and two second passageways 26 and 27 substantially facing the projections 23 on the conductor elements 8. In use, electric cables or wires 28 are passed
through said passageways 26, 27 to be fixed to the conductor elements 8 in the manner described hereinafter.
The first passageways 24 and 25 are defined by the blades 20, 21 and by substantially flat rigid walls 29 integral with said support casing 2. When the blades 20, 21 are in their rest position (as in Figure 6), the first passageways 24, 25 assume a wedge shape.
By inserting any pointed tool through one of the first passageways 24, 25 (for example, with reference to Figure 5, through the first passageway 24, between the rigid wall 29 and the blade 20), this latter is elastically compressed and thrust in the direction of the arrow F (of Figure 5), and its cavity 22 made to substantially slide onto the projection 23 on the conductor element 8, the projection 23 also acting as a guide for the movement of said blade 20. The cavity 22 of the blade 20 then faces the second passageway 26. By inserting an electric cable 28 through said second passageway 26, and through the cavity 22 of the blade 20, then extracting the pointed tool (not shown but conventional) from the first passageway 24, the blade 20 returns elastically to trap the electric cable 28 within said cavity 22, it trapping it by clamping it against the projection 23 on the conductor element 8. The electric cable 28 is hence properly fixed to the conductor element without the need for conventional clips of screw or other type.
Advantageously two independent blades 20, 21 are provided for each conductor element 8. These are accessible via the passageways 24, 25, 26, 27 and can be moved separately. Each blade 20, 21 can hence be used to independently fix just one cable 28, with considerable advantage and ease in using the sprung contact device 1.
Cables 28 fixed to the same conductor element 8 can therefore be connected and released independently.
In completing the description of the modular contact and/or signalling device 1
for electrical panels, it should be noted that it comprises a cover 30 fixable to the support casing 2 by pins (not shown) projecting from said cover 30 and cooperating as an interference fit with holes 31 appropriately provided in said support casing 2. The support casing 2 also presents conventional elastic snap elements 32 to fix the sprung contact device 1 to a conventional frame (not shown).
A modular contact and/or signalling device 1 for electrical panels conceived in this manner is susceptible to numerous modifications and variants, all falling within the scope of the inventive concept; moreover all details can be replaced by technically equivalent elements.
In practice the materials used and the dimensions can be chosen at will according to requirements and to the state of the art.
The said device can also use different operating logics. Thus, in the embodiment shown by way of example, the plate 13 is permanently in contact with the conductor elements 8, hence the reference circuit is closed under rest conditions.
Pressure on the slider 15 causes the opening of the circuit.
In a different embodiment, shown in Figures from 7 to 9, the circuit is open under rest conditions. Pressure on the slider 15 causes the plate 13 to descend so that, given the different position and shape of the conductor elements 8, it comes into contact with them to close the circuit.
The other constructional details are identical and will therefore not be described. Alternative embodiments, not described because they are elementary to an expert of the art, can comprise supports between the two conductor elements 8 to house for example lamps or lamp holders.