EP1766744A1

EP1766744A1 - Variable-size junction box

Info

Publication number: EP1766744A1
Application number: EP05753058A
Authority: EP
Inventors: Bruno Levi
Original assignee: Palazzoli SpA
Current assignee: Palazzoli SpA
Priority date: 2004-07-05
Filing date: 2005-06-15
Publication date: 2007-03-28
Also published as: WO2006002767A1; ITMI20041341A1

Abstract

A variable-size junction box, having a casing which has an open side, and a cover which is detachably associable with the casing in order to form at least one internal chamber. The box has a means for varying the volume of the internal chamber.

Description

VARIABLE-SIZE JUNCTION BOX

The present invention relates to a variable-size junction box.

As it is known, owing to the large number of conductors and cables present in most industrial electrical systems, and in view of the need to be able to connect, repair and modify these systems rather quickly and reliably, these systems are generally installed so as to remain exposed.

According to this method of execution, the cables are inserted in conduits and tubes made of self-extinguishing PVC, which are fixed to the wall and allow to associate an adequate protection of the system with perfect harmonization with the aesthetics of the affected environments, while the wiring and any electrical devices required for the operation of the system are contained in junction boxes, which are likewise fixed to the wall mostly at the points where the tubes branch.

The junction boxes, too, are usually made of self-extinguishing PVC and generally include a casing, whose dimensions can vary according to the various requirements, and a cover, which is closed by snap-on or by virtue of conventional screw-type or quarter- turn systems.

This type of junction box has many problems that, despite appearing to be trivial and negligible, as a whole are decisive for the functional and safe installation of the electrical system. The main drawback lies certainly in the fact that the size of the junction box is fixed and is determined solely and exclusively by the manufacturer, without giving the installer any possibility at all to change them.

On one hand, this forces manufacturers of electrical material to provide a truly wide range of products, and on the other hand it very often forces installers to replace a large number of junction boxes whenever changes to a system are needed.

Further drawbacks can also be found in the various systems for closing and opening the cover of the boxes.

The convenience and ease with which it is possible to open snap-on covers in fact also clashes with the most elementary safety rules, which must be complied with when dealing with electrically live parts, while any presence of screws affects the installation times and manufacturing costs of the boxes.

The aim of the invention is to solve the problems described above by providing a variable-size junction box that allows the installer to change its geometric dimensions, adapting them to the requirements of the situation. Within the scope of this aim, a particular object of the invention is to provide a junction box that has a cover opening and closure system that is simple and practical yet at the same time safe.

A further object of the invention is to provide a junction box that can be manufactured at competitive costs and is at the same time highly reliable. This aim and these and other objects that will become better apparent hereinafter are achieved by a variable-size junction box, comprising a casing, which has an open side, and a cover which is detachably associable with the casing in order to form at least one internal chamber, characterized in that it comprises a means for varying the volume of the internal chamber. Further characteristics and advantages will become better apparent from the description of a preferred but not exclusive embodiment of a junction box according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is an exploded perspective view of the variable-size junction box according to the invention;

Figure 2 is another perspective view of the variable-size junction box according to the invention;

Figure 3 is a perspective view of the variable-size junction box according to the invention in the closed configuration; Figure 4 is a longitudinal sectional view of the variable-size junction box according to the invention in the closed configuration;

Figure 5 is a longitudinal sectional view of the variable-size junction box according to the invention in another step of closure;

Figure 6 is an enlarged-scale view of a detail of Figure 4; Figure 7 is a view of a detail of the variable-size junction box according to the invention during opening.

With reference to the cited figures, a variable-size junction box, generally designated by the reference numeral 1 , comprises a casing 2 which has an open side and a configuration that is substantially similar to the configuration of the known junction boxes commonly used in civil and industrial electrical systems, and a cover 3, which can be associated detachably with the casing 2 so as to form an internal chamber 4.

Both the casing 2 and the cover 3 are generally made of self-extinguishing thermoplastic materials, which ensure excellent resistance to mechanical stresses, heat and fire. The casing 2 may have multiple cable ports, generally designated by the reference numeral 15, or appropriately provided incisions that allow easier opening of the ports.

One or more differently shaped partitions, not. shown in the figures, may be inserted in the casing 2 in order to form multiple internal chambers that are substantially similar to the internal chamber 4. According to the invention the variable-size junction box 1 comprises a means 5 for varying the volume, which allow to change the. geometric dimensions of the internal chamber 4, consequently changing the overall dimensions of the variable-size junction box 1.

More specifically, the volume varying means 5 comprises a sliding engagement means, constituted substantially by a side wall 6, which is formed on the edge of the cover 3 so as to protrude therefrom substantially at right angles to the cover 3 and by two or more flexible elongated members 7, which are formed on the side of the cover 3 that is directed toward the internal chamber 4.

The sliding engagement means allows the relative movement of the cover 3 with respect to the casing 2 and vice versa.

The casing 2 partially enters the cover 3, causing part of the side wall 6 to overlap the side walls of the casing 2, thus forming the internal chamber 4.

The position of the cover 3 may be removably locked relatively to the casing 2 through a stop means 8. The stop means 8 comprises teeth 9 formed on each one of the flexible elongated members 7 cooperating with a serrated portion 10 formed inside the casing 2.

The teeth 9 cooperate with the respective serrated portion 10 in order to prevent the movement of the sliding engagement means in one of the two directions.

Disengagement of the teeth 9 from the serrated portion 10 can occur exclusively by using a tool 12, which by being inserted in the cavity 11 , that can be accessed from outside, allows to bend the corresponding flexible elongated member 7 and therefore allows the free movement of the sliding engagement means.

The hermetic tightness of the variable-size junction box 1 is ensured by a sealing gasket 13 of the O-ring type, which is accommodated in a seat 14 formed externally with respect to the casing 2, so that the gasket is interposed between the casing 2 and the side wall 6.

The use of the variable-size junction box according to the invention is very simple and is described hereinafter.

After fixing the casing 2 to a wall and after performing the necessary wiring of any cables, inserted through the cable ports 15, or after inserting additional components and accessories, the variable-size junction box 1 may be closed by resting the cover 3 on the casing 2 and by applying a slight pressure.

This pressure, by virtue of the sliding engagement means, causes the partial penetration of the casing 2 in the cover 3, the side wall 6 of which partially overlapping the side walls of the casing 2.

The operator, by virtue of the stop means 8, is able to stop the stroke of the cover 3 in preset positions, accordingly varying the geometric proportions and therefore the volume of the internal chamber 4 thus formed.

For safety, because the variable-size junction box 1 can contain electrically live parts, it is necessary to use a tool in order to open the box to perform inspections or maintenance.

The tool 12, for example a screwdriver, may be inserted in the cavity 11 , which can be accessed from the outside, in order to bend the flexible elongated member 7. This maneuver leads to the disengagement of the teeth 9 from the serration 10, allowing the free movement of the sliding engagement means. In practice, it has been found that the variable-size junction box 1 , according to the invention, fully achieves the intended aim and objects, allowing the installer to vary its geometric dimensions, adapting them to requirements of the situation, and reserving exclusively to assigned personnel the opening and closure of the cover and the consequent access to any live parts of the system.

The junction box thus conceived is susceptible of modifications and variations, within the scope of the appended claims. All the details may be replaced with other technically equivalent elements.

In practice, the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

Claims

1. A variable-size junction box, comprising a casing, which has an open side, and a cover, said cover being detachably associable with said casing in order to form at least one internal chamber, characterized in that it comprises a means for varying the volume of said internal chamber.

2. The junction box according to claim 1 , characterized in that said means for varying the volume comprises a sliding engagement means, which allows a motion of said cover with respect to said casing when they are mutually associated, said casing partially penetrating in said cover in order to form said internal chamber.

3. The junction box according to one or more of the preceding claims, characterized in that said sliding engagement means comprises a side wall, formed by said cover, and flexible elongated members formed on the side of said cover that is directed toward said internal chamber.

4. The junction box according to one or more of the preceding claims, characterized in that said volume varying means comprises a stop means which is suitable to stop the stroke of said sliding engagement means in preset positions.

5. The junction box according to one or more of the preceding claims, characterized in that said stop means comprises at least one tooth formed on each one of said flexible elongated members, and a serrated portion formed inside said casing, said at least one tooth cooperating with said serrated portion in order to prevent the sliding of the sliding engagement means in one direction.

6. The junction box according to one or more of the preceding claims, characterized in that each one of said flexible elongated members comprises a cavity that can be accessed from the outside with a tool which can be inserted therein in order to bend said flexible elongated members and cause the consequent disengagement of the stop means.

7. The junction box according to one or more of the preceding claims, characterized in that it comprises at least one sealing gasket, which is interposed between said side wall and said box-like structure.