NL2001817C2

NL2001817C2 - Electrical installation box forming method for making electrical connections between different electrical conductors in building, involves applying film of predetermined size on predetermined part of mold, and connecting film to box

Info

Publication number: NL2001817C2
Application number: NL2001817A
Authority: NL
Inventors: Antonie De Hoog
Original assignee: Attema Kunststoffenind
Priority date: 2008-07-17
Filing date: 2008-07-17
Publication date: 2010-01-19

Abstract

The method involves applying a film (32) of predetermined size on a predetermined part of a mold, and closing the mold. An installation box (2) is formed in the mold by injection molding process, and the film is connected to the installation box. The installation box is provided with multiple spouts (4) that are directed outward from openings (30) of a wall (6) of the installation box. The openings are closed by a star-shaped piece of the film. An independent claim is also included for an electrical installation box comprising an opening.

Description

Title: Method of forming an object, in particular an installation box, in a mould, and installation box formed by the method

The present invention relates to a method of forming an object, in particular an installation box, in a mould. The present invention further relates to an installation box 5 obtained by the method according to the present invention.

In the technical field of electrical installations in buildings, installation boxes are known e.g. for making electrical connections between different electrical conductors. The installation boxes are usually included in poured concrete walls (including side walls, ceilings, floors, roofs), but may also be built in or on a wall at a later time. The installation boxes may or may 10 not comprise one or more spouts, directed outwards from an opening in a wall of the installation box. Each spout is intended to accommodate an end of an installation pipe through which (normally isolated) electrical conductors may be fed to the installation box, using an opening in the wall of the box at the location where the spout is connected to the box. When the installation box is newly manufactured and not yet in use, each spout is closed 15 off by a removable port such that either the cross-section of the spout is initially closed at some point along the length of the spout, or the opening in the wall of the installation box is initially closed. If the installation box does not comprise spouts, or at a location of the installation box where a spout is absent, the wall of the installation box may be provided with one or more removable ports. When electrical conductors need to be fed into the installation 20 box, one or more ports need to be removed to enable the electrical conductors to pass from the outside of the box to the inside of the box, or vice versa.

The ports traditionally are formed in the same injection moulding process which is performed to mould the installation box as a whole as a unitary part, or at least to mould a main body of the installation box. Typically, a port would comprise a plate-shaped, usually 25 substantially coin-shaped part having a predetermined, possibly variable thickness across its surface, and extending over the cross-section of the wall opening of the installation box or the cross-section of the spout, where the plate-shaped part is contiguously or substantially contiguously connected along its circumference to the wall of the installation box or the inner wall of the spout, depending on the configuration of the installation box, as explained above. 30 The connection between the plate-shaped part of the port and the remainder of the installation box is designed such that for removing the port a predetermined force is necessary which will break the connection at least locally. However, considerable force is required. The port may be removed using a tool such as a knife or a screwdriver to 2 respectively cut or tear out the port from the box. As is known from e.g. EP1868270, also an installation pipe end may be used to open a port by tearing the port or the connection.

In an installation box provided with spouts, the port may be provided either at or near an end of the spout facing a wall of the box, or at or near an end of the spout facing away from a 5 wall of the box.

When an installation box is provided with spouts, and a port is provided at or near an end of each spout facing away from a wall of the box, then installation pipes may only be inserted into the spouts after the ports have been removed. An insertion of an installation pipe into a spout may serve to remove the port by tearing the connection between the plate-10 shaped part and the spout, or the port may be removed by a tool before an installation pipe is inserted into it. Spouts not used remain closed by their ports. When pouring concrete on the installation box with the installation pipes attached to it, no concrete may leak into the installation box or installation pipes, and consequently there is no risk of concrete block any passage of conductors in the installation box or installation pipes. The same does not hold 15 true when ports would have been removed from spouts not having an installation pipe inserted into them, e.g. because initially the port was opened to provide an installation pipe in the spout, but later the installation pipe was removed without closing the spout. In the latter case, concrete may leak into the installation box, and may block the installation box or installation pipes connected to it. Unused spouts having their port removed therefore need to 20 be closed again by a cap or the like.

When an installation box is not provided with spouts, a port is provided in a wall of the box. In that case, installation pipes may only be inserted into the installation box after the ports have been removed. An insertion of an installation pipe into the installation box may serve to remove the port by tearing the connection between the plate-shaped part and the 25 wall of the installation box, or the port may be removed by a tool before an installation pipe is inserted into the corresponding opening. Openings not used remain closed by their ports. When pouring concrete on the installation box with the installation pipes attached to it, no concrete may leak into the installation box or installation pipes, and consequently there is no risk of concrete blocking any passage of conductors in the installation box or installation 30 pipes. The same does not hold true when ports would have been removed from the installation box to provide openings not having an installation pipe inserted into them, e.g. because initially the port was opened to provide an installation pipe in the installation box, but later the installation pipe was removed without closing the opening. In the latter case, concrete may leak into the installation box, and may block the installation box or installation 35 pipes connected to it. Unused openings having their port removed therefore need to be closed again by a cap or the like.

3

When an installation box is provided with spouts, and a port is provided at or near an end of each spout facing a wall of the box, installation pipes may be inserted into the spouts without opening the ports (since an installation pipe does not reach the port in the spout). The ports may remain intact, and when pouring concrete on the installation box with the 5 installation pipes attached to it, no concrete may leak into the installation box or installation pipes, and consequently there is no risk of concrete blocking any passage of conductors in the installation box or installation pipes. The same holds true when one or more of the ports having installation pipes inserted in them would be opened or removed. Spouts into which an installation pipe was inserted, but from which the installation pipe was removed later before 10 pouring of concrete, remain closed since the port was not opened.

In the latter situation with ports being provided at or near an end of the spouts facing a wall of the installation box, however, a problem occurs in that it is difficult to remove the ports after the installation box has been cast in the concrete wall. First, in an installation box having multiple spouts, of which one or more are not used, it is difficult to determine which one of the 15 ports leading to the spouts actually used need to be removed. Extra actions are required to record which one(s) of the ports need to be removed, and any mistake in this determination (where a wrong port is removed) costs time which is wasted. Moreover, the ports can only be reached from the interior of the installation box, which allows very little working space for a tool to remove or at least open the ports.

20 An object of the invention is to provide an object, in particular an installation box, allowing an opening to be created with a relatively low force. In case of an installation box, more particularly, the object of the invention is to allow a port to be opened or removed requiring only a relatively low force.

According to one aspect, the present invention provides a method of forming in a 25 mould by injection moulding an electrical installation box for making electrical connections between different electrical conductors, the installation box comprising an opening or a recess to enable passing of electrical conductors, the method comprising: providing a film (Dutch: “folie”) of predetermined dimensions on a predetermined location in the mould, when it is open; closing the mould; and forming the installation box in the mould by injection moulding, 30 wherein the film overlaps the opening or recess in the installation box at least partially, and wherein the film is connected to the installation box along at least a part of the circumference of the opening or recess.

It is noted that EP 1,133,222 and EP 1,921,732 both disclose a method for injection moulding a box provided with a membrane. The membrane is gas permeable to allow the box 35 to breath while moisture and dirt are prevented from entering the housing.

In the moulding process, an opening for passing electrical conductors into the installation box is closed by the film. The film can be opened by tearing or rupture. The film is 4 produced separately from the object, thereby to provide the film with predetermined properties in a quality which can be maintained at a high level. The film is used in the same process as moulding the object, whereby a moulding cycle time is virtually unaffected. The mechanical properties of the film may be chosen such that it can be tom with a relatively low 5 local force, while at the same time being strong enough to withstand a relatively high distributed force or pressure.

The film used in the method of the invention may be e.g. a stretched or unstretched extruded film of crystalline polypropylene, a cast film of crystalline polypropylene, or any other film of a synthetic or other material, like paper or cloth material, either woven or nonwoven, 10 preferably but not exclusively electrically a non-conducting or low-conducting material. This film may be laminated on one side or both of its sides with a film of a low-melting resin, such as a low-density polyethylene, an ethylene-vinyl acetate copolymer, or the like, e.g. by direct extrusion laminating, or the film is coated on one side or both sides with e.g. a solvent-based adhesive. In either way, a laminated film is produced.

15 When producing an object, such as an installation box, a piece of this film having a predetermined form and dimensions is placed on an inner wall of a mould, e.g. by adhesion (e.g. using an adhesive side of the film to adhere it to the inner wall of the mould, or by electrostatically charging the film to make it adhere to the inner wall of the mould) or by suction (using a tool energized by vacuum and compressed air to pick up and to place the 20 piece of film on the inner wall of the mould). The placement may be performed by machine or robot in an automated process. The film may have been cut, in particular automatically cut, from a web stored on a roll, or from sheets of film.

Next, the mould is closed to form a cavity of predetermined shape according to the object to be formed, the cavity containing the film on a part of a surface of a mould part. A 25 section of a mould counterpart lies against the film, where the film is located between the mould part and the mould counterpart, and said section shapes a desired opening of the object. A moulding resin is fed to the cavity defined by the mould part and the mould counterpart to shape the object in an injection moulding process. In the injection moulding process, the film adheres to, or fuses with the moulding resin at least at predetermined 30 locations near an opening or recess to be formed in the object. Accordingly, when the mould is opened, an object has been manufactured having one or more openings or recesses wholly or partly overlapped with the film, and having the rest of the film being a unitary part of the object.

In case of the object being an installation box, ports of the installation box may be 35 provided by the film. Such ports may be situated in a wall of the installation box, or in spouts of the installation box, e.g. at or near an end of a spout facing the wall of the installation box, or at or near an end of a spout facing away from the wall of the installation box.

5

In particular when the film port of the spout is located at or near an end of the spout facing the wall of the installation box, where the film port is not opened when an installation pipe is inserted into the spout, the film port may be opened easily after the installation box has been cast into a concrete wall by a wire pulling spring, or electrical conductors moved 5 from an installation pipe to the installation box while rupturing and thereby opening the film port, or in the reverse direction while also rupturing and thereby opening the film port. No extra action is required.

In an embodiment of the present invention, the installation box is provided with a plurality of spouts directed outwards from respective openings in at least one wall of the 10 Installation box, and a single piece of film closes all wall openings. In the moulding process, only one piece of film needs to be handled and provided on a predetermined location in the mould, thereby avoiding having to provide different pieces and shapes of film in complex multiple handling and placing procedures before an installation box can be mould. This saves considerable equipment investment, time and cost. In particular, where the installation box, 15 along a circumference of a side wall thereof, is provided with a plurality of spouts directed outwards from respective openings in the side wall, a single, substantially star-shaped piece of film may close all wall openings.

In a further aspect of the present invention, there is provided an installation box for making electrical connections between different electrical conductors , comprising an opening 20 or recess, and further comprising a film which overlaps the opening or recess at least partially, and wherein the film is connected to the installation box along at least a part of the circumference of the opening or recess, which installation box is characterized in that the film is produced separately from and prior to the object, in that the installation box is made from a moulding resin by injection moulding, and in that, in the injection moulding process, the film 25 adhered to, or fused with the moulding resin.

In an embodiment of the present invention, the film is provided with a weakened area, comprising e.g. at least a perforation and/or a notch, which does not pass a liquid. Such a film is very suitable, on the one hand, for closing an opening during pouring of concrete, where the concrete may reach the film to exert a distributed force or pressure thereon, to avoid 30 water or concrete to pass the film, and, on the other hand, to be opened by tearing or rupture simply by pushing a spring or wire or other sharp or blunt object against the film, whereby the film will give way starting from the weakened area.

In an embodiment of the present invention, the installation box has a centre line, and the wall is a side wall of the installation box, wherein the side wall extends substantially 35 parallel to the centre line, and extends essentially at an obtuse angle to the centre line in the area of the opening. In this way, the opening, and thereby also the film covering the opening, is tilted to the top side of the installation box, making the film better reachable and better 6 adapted to be torn or ruptured from the top side, in particular when the installation box has been built into a wall.

In an embodiment of the present invention, the spout is flared at an end thereof facing away from the wall. Such a trumpet-like or funnel-shaped design of the spout promotes the 5 ease of inserting an end of an installation pipe into the spout without compromising the reliability of the connection between the installation pipe and the spout.

Further aspects, features and advantages of the present invention are described in more detail in the following, referring to the attached drawings which depict non-limiting exemplary embodiments.

10 Figure 1 shows a perspective view of an electrical installation box in an embodiment of the present invention.

Figure 2 shows a top view of the electrical installation box of Figure 1.

Figure 3 shows a bottom view of the electrical installation box of Figure 1.

Figure 4 shows a cross-section of the electrical installation box of Figure 1 along a 15 plane IV-IV as indicated in Figure 2.

Figure 5 shows a cross-section of a spout of the electrical installation box of Figure 1.

Figure 6 shows a broadsheet of a film used in the electrical installation box of Figure 1.

Figure 7 illustrates the manufacture of the electrical installation box of Figure 1.

In the different Figures, the same reference symbols indicate the same elements or 20 elements having the same or a similar function.

Figures 1,2, 3,4 and 5 show an electrical installation box 2 provided with eight spouts 4 on an essentially cylindrically or ring shaped side wall 6 of the box 2. The number of spouts 4 and the configuration thereof, to be described in greater detail hereinbelow, may vary. In addition, or alternatively, one or more spouts 4 may be provided at a bottom wall 8 of the box 25 2 (situation not shown in the Figures).

In the interior of the box 2 two ribs 10 are provided, extending from the bottom wall 8 along the side wall 6 parallel to a central axis 12 (Figure 4) of the box 2 at right angles to the bottom wall 8. The ribs 10, which are located opposite to each other in the box 2, are provided with threaded holes 14, intended to receive screws (not shown) used for mounting a 30 cover (not shown) on the box 2. The holes 14 are provided at the ends of the ribs 10 facing away from the bottom wall 8.

As shown in detail in Figure 5, the spout 4 comprises a first section 20 having a circular inner cross-section with a first diameter, and having a first length. The first section 20 links up with the side wall 6 of the box 2. A second section 22 links up with the first section 20 through 35 an intermediate, lobe-shaped section 24. The second section 22 has a circular inner cross-section with a second diameter, and has a second length. The second diameter is larger than the first diameter. A tapering or flaring orfrusto-conically shaped third section 26 links up with 7 the second section 22, where the inner cross-section of the third section 26 at the end thereof facing the second section 22 is smaller than the inner cross-section of the third section 26 at the opposite end thereof. Together, the first section 20, the lobe-shaped section 24, the second section 22, and the third section 26 constitute the spout 4.

5 As shown in Figures 1 and 5, each spout 4 opens out into the box 2 in the side wall 6 near the bottom wall 8 with an opening 30 having an essentially elliptical cross-section. In the area of the opening 30, the side wall 6 does not extend substantially parallel to the centre axis 12, but extends essentially at an obtuse angle to the centre axis 12 of the box 2. Here, the direction of the side wall 6 in the area of the opening(s) 30 is defined by the circumference of 10 the opening 30, and the obtuse angle is approximately 172°.

Each opening is covered or closed by a film 32, which constitutes a plane extending at an obtuse angle to the centre axis 12 of the box 12. Each film 32 is connected to the box 2 along the circumference of the opening 30.

Figure 6 shows a broadsheet of a film 34 having a central part 36 and eight radial parts 15 38, making the film 34 substantially star-shaped. Each radial part 38 may be shaped as film 32, while the central part 36 may be shaped as the bottom wall 8 of the box 2. The film 34 may be provided with a weakened area, e.g. a perforation along line 39 or the like.

As illustrated in Figure 7, prior to manufacturing the box 2 in an injection moulding process, the film 34 is placed on a surface of a moulding part 40 used in the injection 20 moulding process, where the central part 36 of the film 34 is located on a surface part of the moulding part 40 intended to shape one side of the bottom wall 8 of the box 2, and the radial parts 38 are located, as indicated by the arrows 42, on surfaces of the moulding part 40 . intended to shape the side wall 6 of the box 2 in the area of the openings 30. The film 34 is held on the moulding part 40 by vacuum or any other means to provide a force for removably 25 adhering the film 34 to the moulding part 40, such as an electrostatical force.

When the film 34 has been placed on the surface of the moulding part 40, the moulding part 40 is brought together with one or more associated moulding parts (not shown in Figure 7) to form a moulding cavity in which the film 34 is located at a predetermined position. The moulding cavity is shaped to form the box 2. Next, the mould formed by the moulding parts is 30 filled with liquid moulding material which is allowed to cure before the mould is opened to obtain the box 2 with the film connected to it to close the openings 30 of the box 2.

In this way, all openings 30 of the box 2 are both formed, and closed or covered by the one-piece film 34, in the single injection moulding step. Alternatively, it is possible to use separate film parts positioned at appropriate surfaces of the moulding part 40, each covering 35 one or more openings 30. As a further alternative, a spout 4 may be closed at another location along its length, e.g. at or near the end thereof facing away from the side wall 6, by appropriately positioning a film at a moulding part.

δ

In whatever position the film may close the spout 4, the film may prevent any water or concrete from entering the installation box when pouring concrete around the box 2.

In use, an installation pipe may be inserted into a spout 4. An installation pipe having an outer diameter slightly less than the first diameter of the first section 20 will be inserted into 5 the spout 4 until the end of the installation pipe reaches a stop 50 (Figure 5). A film provided at the opening 30 will not be contacted by the installation pipe. An installation pipe having an outer diameter slightly less than the second diameter of the second section 22, but larger than the first diameter of the first section 20, will be inserted into the spout 4 until the end of the installation pipe reaches the lobe-shaped section 24. It will be clear that a film provided at 10 the opening 30 will not be contacted by the installation pipe.

The insertion of the installation pipe in the spout 4 is simplified by the shape of the third section 26, where the trumpet-shaped or funnel-shaped third section 26 allows to guide a non-coaxially aligned installation pipe into the second section 22.

If the film is provided at or near an end of the spout 4 facing away from the side wall 6, 15 or in the spout 4 away from the opening 30, then the film may be ruptured by the insertion of the installation pipe. If the film is provided at the opening 30 of the box 2, then the film may be ruptured by the insertion of one or more installation wires, either from an installation pipe through a spout 4 into the box 2, or from the box 2 into an installation pipe through a spout 4. In the latter case, the obtuse angle at which the film is extending relative to the side wall 6 of 20 the installation box 2 facilitates the rupturing of the film by the installation wires.

Rupturing of the film may be possible by the inherent mechanical properties of the film, and may be enhanced or controlled by providing weakened spots, lines or areas in the film, such as a perforation, a notch, and the like.

As required, detailed embodiments of the present invention are disclosed herein; 25 however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the 30 terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. From the preceding description it will be clear that instead of an installation box, any object having an opening or recess with a film at least partially overlapping the opening or recess may be formed within the teaching of the present disclosure.

35 The terms "a", "an", “first”, “second” etc. as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. In addition, singular references do not exclude a plurality. The term another, as used herein, is defined as 9 at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

The following clauses provide a description of embodiments of the present invention: 5 1. Method for forming an object in a mould, the object comprising an opening or a recess, the method comprising: providing a film of predetermined dimensions on a predetermined location in the mould, when it is open; closing the mould; and 10 forming the object in the mould, wherein the film overlaps the opening or recess in the object at least partially, and wherein the film is connected to the object along at least a part of the circumference of the opening or recess.

2. Method according to claim 1, wherein the object is an installation box comprising an opening or a recess.

15 3. Method according to clause 2, wherein the installation box is provided with a spout directed outwards from an opening in a wall of the installation box, the film closing the spout.

4. Method according to clause 3, wherein the film closes the wall opening.

5. Method according to clause 4, wherein the installation box is provided with a plurality of spouts directed outwards from respective openings in at least one wall of the installation 20 box, and wherein a single piece of film closes all wall openings.

6. Method according to clause 4, wherein the installation box, along a circumference of a side wall thereof, is provided with a plurality of spouts directed outwards from respective openings in the side wall, and wherein a single, substantially star-shaped piece of film closes all wall openings.

25 7. Installation box, comprising an opening or recess, and further comprising a film which overlaps the opening or recess at least partially, and wherein the film is connected to the installation box along at least a part of the circumference of the opening or recess.

8. Installation box according to clause 7, comprising at least one spout directed outwards from an opening in a wall of the installation box, the film closing the spout.

30 9. Installation box according to clause 8, the film closing the wall opening.

10. Installation box according to any of clauses 7-9, wherein the film is provided with a weakened area which does not allow a liquid to pass.

11. Installation box according to clause 10, wherein the weakened area comprises at least a perforation and/or a notch.

35 12. Installation box according to any of clauses 8-11, wherein the installation box has a centre axis, and the wall is a side wall of the installation box, and wherein the side wall 10 extends substantially parallel to the centre axis, and extends essentially at an obtuse angle to the centre axis in the area of the opening.

13. Installation box according to any of clauses 8-12, wherein the spout is flared at an end thereof facing away from the wall.

5

Claims

Method for injection molding an installation box (2) for establishing electrical connections between different electrical conductors, said installation box comprising an opening (30) or recess for passage of the electrical conductors, the method comprises: applying a film (32, 34) of predetermined dimensions to a predetermined location in the mold when it is opened; closing the mold; and molding the installation box in the mold by injection molding, wherein the foil at least partially overlaps the opening or recess in the object, and wherein the foil is connected to the object along at least a part of the circumference of the opening or recess.

Method according to claim 1, wherein the foil closes the opening or recess and can be opened by breaking or tearing.

3. Method as claimed in claim 1 or 2, wherein the installation box (2) is provided with at least one spout (4) which is directed outwards from an opening (30) in a wall of the installation box, wherein the foil (32) close the spout (4).

The method of claim 3, wherein the foil (32) closes off the wall opening (30).

5. Method according to claim 4, wherein the installation box is provided with a number of spouts (4) which are directed outwards from respective openings (30) in at least one wall (6) of the installation box (2), and wherein a single piece foil (34) closes all wall openings.

6. Method according to claim 4, wherein the installation box (2) is provided along a circumference of a side wall (6) thereof with a number of spouts (4) which are directed outwards from respective openings (30) in the side wall, and wherein a single, substantially star-shaped piece of foil (34) closes off all wall openings.

An installation box (2) for establishing electrical connections between 35 different conductors, comprising an opening (30) or recess, and further comprising a foil (32,34) which at least partially overlaps the opening or recess, and wherein the foil is connected to at least a part of the circumference of the opening or recess with the installation box, characterized in that the film is manufactured separately from and prior to the installation box, that the installation box is made by injection molding from a casting resin, and that the foil during injection molding is connected to the installation box by adhesion to or fusion with the casting resin. 5

Installation box according to claim 7, comprising at least one spout (4) which is directed outwards from an opening (30) in a wall (6) of the installation box (2), wherein the foil (32) closes the spout.

Installation box according to claim 8, wherein the foil (32) closes off the wall opening (30).

Installation box according to one of claims 7 to 9, wherein the foil (32, 34) is provided with a non-liquid-permeable weakened area (39).

Installation box according to claim 10, wherein the weakened area (39) comprises at least one perforation and / or a notch.

12. Installation box according to any of claims 8-11, wherein the installation box (2) has a center line (12) and the wall is a side wall (6) of the installation box (2), and wherein the side wall (6) is in extends substantially parallel to the axis (12) and extends in the region of the opening (30) at an obtuse angle with the axis (12).

Installation box according to one of claims 8 to 12, wherein the spout (4) runs out of an end (26) thereof remote from the wall. 25

An installation box according to any one of claims 7-12, wherein the foil can be opened by breaking or tearing.