DEVICE FOR DRAWING THROUGH ELECTRIC LEADS TO CUBICLES OR CASINGS FOR ELECTRIC EQUIPMENT

Abstract: A device for drawing through electric leads to cubicles or casings (3) for electric equipment includes a lead-through member (9) with lead-through and sealing portions (10) which are disposed beside each other and which are made of elastic material and workable to adapt as sealing collars (10') to electric leads (2') extending therethrough, whereby the lead-through and sealing portion (10) of the lead-through member (9) as well as connecting portions (11) forming part of the lead-through member (9) and connecting the lead-through and sealing portions (10) to each other are provided in one piece and made of the same elastic material. In order for the lead-through and sealing portions (10) to adapt to and sealingly engage an electric lead, the thicknessof which is substantially equal to or substantially less than the width of the lead-through and sealing portion, and adapt to and sealingly engage electric leads of various cross-sectional shape and in order for the device to be brought to adapt to and sealingly engage the outer side of the cubicle or casing (3) onto which it shall be fastened, said elastic material has a hardness of 70-95 Shore A.

Description: Device for drawing through electric leads to cubicles or casings for electric equipment. The present invention relates to a device for drawing through electric leads to cubicles or casings for electric equipment, said device including a lead-through member with lead-through and sealing portions which are disposed beside each other and which are made of elastic material and work¬ able to adapt as sealing collars to electric leads extending therethrough, whereby the lead- hrough and sealing portions of the lead-through member as well as connecting portions forming part of the lead-through member and connecting the lead-through and sealing portions to each other are provi¬ ded in one piece and made of the same elastic material. Devices of the above type are already known from e.g. DE-A-16 15 845, GB-A-1 154 929 and DE-B2-21 09 548. However, it has been noticed that the elastic material the prior art devices are made of, is not of such a type that it has all the following properties: 1. The lead-through and sealing portions can adapt to and sealingly engage an electric lead, the thickness of which is substantially equal to the width of the lead- -through and sealing portion, but said portion can addi¬ tionally adapt to and sealingly engage leads of substan¬ tially less thickness; 2. The lead-through and sealing portions can adapt to and sealingly engage electric leads of various cross-sectio- nal shape, e.g. round leads, oval leads or flat leads; 3. The device can be brought to adapt to and sealing¬ ly engage the outer side of the cubicle or casing onto which it shall be fastened. The object of the present invention is to provide a device of the aforementioned type and having all the above properties. This is arrived at while the device according to the invention has been given all the characterizing features of subsequent claim 1. The invention will be further described below with reference to the accompanying drawings, in which fig. 1 is a perspective view of the lead-through device of the inven¬ tion from above; fig. 2 is an enlarged view of the device of fig. 1 from above; fig. 3 is a section along the line III-III in fig. 2; fig. 4 is a section through a part of the device of fig. 1, whereby drawing of an electric lead through the device has been initialized; fig. 5 is a sec- tion similar to fig. 4 but shows the lead completely drawn through; fig. 6 is a hardness diagram; fig. 7 is a break elongation diagram; and fig. 8 is a bending module dia¬ gram. The lead-through device 1 illustrated in the drawings is intended to permit through drawing of electric leads 2 from the outside into a cubicle or so called casing or housing for connection to electric equipment (not shown) in said cubicles or casings 3. The lead-through device 1 is intended to be provided on one outer side 4 of the cubic- le or casing 3 such that it covers an opening (not shown) in said side and engages the surface 5 of said side around said opening. The lead-through device 1 has four holes 6 for bolts 7 provided on the side 4. By threading the lead- -through device 1 onto the bolts 7, the device may be tigh- tened against the cubicle or casing 3 by means of nuts 8. The lead-through device 1 has a lead-through member 9 and lead-through and sealing portions 10, which are disposed beside each other and made of elastic material and which are workable to connect as sealing collars 10' to electri- cal leads 2 extending through said lead-through and sea¬ ling portions 10. The lead-through and sealing portions 9 of the lead- -through member 9 as well as connecting portions 11 included in said member 9 and connecting the lead-through and sealing portions 10 to each other are formed in one piece and of the same elastic material. Hereby, the lead-through and sealing portions 10 may be disposed close to each other. The lead-through and sealing portions 10 preferably trans¬ form directly into the connecting portions 11 and the lead- -through member 9 can be made in one piece of the same elastic material. Preferably, the lead-through member 9 and a fastening portion 12 belonging thereto are also formed in one piece and of the same elastic material. While the fastening por- tion 12 is also made of elastic material, it may adapt it- self to the surface 5 of the side 4 of the cubicle or ca¬ sing 3, whereby the fastening portion 12 may sealingly en¬ gage the surface 5. The members of the lead-through device 1 manufactured as a unit do not merely provide close lead-throughs for the electric leads, but they also provide sealing against the surface 5 without the use of separate sealing means for obtaining the required sealing between said surface 5 and the lead-through device 1. The fastening portion 12 preferably consists of a fas¬ tening flange which extends around the lead-through mem¬ ber 9 and in which the holes 6 are provided. In order to ensure that all parts of this fastening flange 12 are tigh¬ tened against the surface 5 when the nuts 8 are tightened, a rigid tightening frame 13 of metal or another suitable material may be positioned on the fastening flange and be¬ neath the nuts 8 such that said nuts press against the fastening flange via the tightening frame 13. Alternatively, the fastening flange may be provided with reinforcements or stiffenings for obtaining efficient rigidity if requi¬ red. The lead-through member 9 is preferably three times higher than the fastening flange 13 and provided with lead- -through passages 14. These passages open at the inner side 15 of the lead-through device 1, extend through the lead-through member 9 towards the outer side 16 of the lead-through device 1 and are here preferably completely sealed by the lead-through and sealing portions 10 of the lead-through member 9 forming parts of said outer side 16. The outer side 16a of the lead-through and sealing portions 10 and the outer side 16b of the connecting portions 11 are aligned or substantially aligned and define an even or substantially even outer side 16 to the lead-through de¬ vice 1. Wall portions 17 between the lead-through passa- ges 14 are substantially thicker than the lead-through and sealing portions 10, which are preferably thin-walled in order to yield at insertion of the electric lead 2 and for adaptation thereto. While the aligned or substantially aligned outer sides 16a, 16b define an even or substantially even outer side 16 to the lead-through device 1, no water, damp or dirt collecting depressions are formed therein. While the lead- through passages 14 extend as defined above, they may pro¬ vide guidance to electric leads 2 extending therethrough. While the thick wall portions 17 between the lead-through passages 14 define the connecting portions 11, said wall portions show sufficient rigidity for the device to be rug¬ ged even though the connecting portions 11 are made of the same elastic material as the lead-through and sealing por- tions 10. Each lead-through and sealing portion 10 has preferably a circular periphery 18 at which it transforms into the connecting portions 11. Each lead-through and sealing por¬ tion 10 also has a centrally disposed, preferably circular hole (not shown), which is sealable by a removable plug (not shown) or similar. Each lead-through and sealing por¬ tion 10 also becomes thinner in an inwards direction from the periphery 18 towards the fractural impression 19 or the hole. The illustrated embodiment of the lead-through device 1 is of standard size and includes 24 smaller lead-through and sealing portions 10 and 9 larger lead-through and sea¬ ling portions 10. Thereby, the lead-through member 9 ex¬ tends in between the holes 6 at both end portions of the lead-through device 1 and the portions of the lead-through member 9 provided between said holes 6 each comprise two lead-through and sealing portions 10. The remaining lead- -through and sealing portions 10 are arranged in five and three rows respectively, with four and three such portions in each row respectively. Alternatively, the lead-through device 1 may comprise e.g. 4O lead-through and sealing portions 10, whereby all portions are equally large. The lead-through member 9 and preferably also the fas- tening portion 12 are made of an elastic thermoplast of a suitable type and the entire lead-through device 1 with the exception of the tightening frame 13 can be manufactured in one working step by means of a plastic tool. The lead- -through device 1 may alternatively be made of another elas- tic material than a thermoplast. In order for the lead-through and sealing portions 10 to easily adapt to leads of various shape and thickness, the elastic material has a hardness of 70-95 Shore A (see fig. 6). An elastic material with this hardness also effi- ciently adapt to the outer side 4 of the cubicle or casing 3 whether this is even or which is normal, somewhat uneven. If the hardness of the material is substantially lower than 70 Shore A the device becomes too unstable, and if the hard¬ ness is substantially higher than 95 Shore A the device becomes too inelastic for providing the required sealing. Said range of hardness for the elastic material also means that it may sealingly adapt to a "thin" electric lead 2a as .is shown in fig. 5 with dashed and dotted lines. The elastic material preferably also have a break elongation of 300 %, most preferably 600 % (see fig. 7). This means that the material is extensible 3 times, pre¬ ferably_6_ times, before it breaks. It is hereby ensured e.g. that it can adapt to and sealingly engage "thick" elect ric leads 2 as is shown with solid lines in fig. 5. The elastic material should preferably also have a bending module at 23°C within the range of 100-130, most preferably about 117. An elastic material with this ben¬ ding module has e.g. such "resilient properties" that it can adapt to and sealingly engage round as well as oval elect- ric leads 2. The inner side 15 of the lead-through device 1 is pre¬ ferably arcuate between parts of the fastening portion 12 provided with the holes 6 in such a way that said parts of the fastening portions 12 are situated at some distance from the surface 5 of the side 4 when the lead-through de¬ vice 1 engages said surface 5 for attachment to said side 4. * Hereby, said parts of the fastening portion 12 can be held down by the nuts 8, whereby the entire lead-through device 1 is tightened with a large pressure against the side 4. At insertion or drawing of an electric lead 2 in a lead-through and sealing portion 10 intended therefor, said portion 10 will yield (see fig. 5), and thereby the frac- tural impression 19 or the hole sees to that the portion 10 is not teared apart in the middle. While the periphery 18 has the same circular shape as the electric lead 2, the portion 10 will "flange out" as much around said lead and form a sealing collar engaging a part of the length of the electric lead (see fig. 5). The invention is not limited to the embodiment descri- bed and shown in the drawings, but may very within the scope of the following claims. As examples of alternative em¬ bodiments could be mentioned that the device may have one or several fastening portions and these may be of another type than a fastening flange; the lead-through and sealing portions can be arranged in another plane than described; the connecting portions need not be substantially thicker than the lead- hrough and sealing portions; the connec¬ ting portions need not form part of wall portions between lead-through passages; lead-through passages are not abso- lutely necessary, but the lead-through and sealing por¬ tions and the connecting portions may form a substantially planar wall; the lead-through and sealing portions may have a circumference of other than circular shape and the central fractural impression or the central hole may have another than circular shape and the number of lead-through and sealing portions may differ from what is described and shown above.

Claims: Claims : 1. Device for drawing through electric leads to cubic¬ les or casings (3) for electric equipment, said device including a lead-through member (9) with lead-through and sealing portions (10) which are disposed beside each other and which are made of elastic material and workable to adapt as sealing collars (10') to electric leads (2') extending therethrough, whereby the lead-through and sea¬ ling portions (10) of the lead-through member (9) as well as connecting portions (11) forming part of the lead- -through member (9) and connecting the lead-through and sealing portions (10) to each other are provided in one piece and made of the same elastic material, c h a r a c¬ t e r i z e d i n that the elastic material has a hard¬ ness of 70-95 Shore A. 2. Device according to claim 1, c h a r a c t e r i¬ z e d i n that the elastic material has a break elonga¬ tion of over 300 %, preferably about 600 %. 3. Device according to claim 1 or 2, c h a r a c ¬ t e r i z e d i n that the elastic material has a ben- ding module within the range of 100-130, preferably about 117, at 23°C. 4. Device according to any preceding claim, c h a ¬ r a c t e r i z e d i n that the lead-through member (9) has a fastening flange (12) which extends around said member and with an inner side is engageable from outside with an outer surface (5) around an opening in one side (4) of the cubicle or casing (3), whereby the fastening flange (12) has holes (6) for attachment means (7, 8) for bracing the device (1) and whereby the lead-through member (9) and the fastening flange (12) are designed in one piece and made of the same elastic material such that said faste¬ ning flange is adaptable to the surface (5) for obtaining a sealing between said surface and the device (1). 5. Device according to claim 4, c h a r a c t e r i- z e d i n that a tightening frame (13) is positionable on the fastening flange (12) to permit tightening of said fastening flange (12) against the surface (5) of the cubic¬ le or casing (3) by means of said tightening frame (13). 6. Device according to claim 4 or 5, c h a r a c ¬ t e r i z e d i n that it has an inner side (15) which is bent in such a way between those portions of the faste¬ ning flange (12) being provided with attachment holes (6), that said portions of the fastening flange (12) are situa¬ ted at some distance from that surface (5) against which the device (1) is to be tightened, whereby said portions of the fastening flange (12) may be pressed inwardly to¬ wards said surface (5) when the device (1) is tightened by means of attachment means (7, 8) in the attachment holes (6). 7. Device according to any preceding claim, c h a ¬ r a c t e r i z e d i n that the lead-through member (9) extends in between two attachment holes (6) in a portion of the fastening flange (12) at one end portion of the de¬ vice (1) and in between two other attachment holes (6) in another portion of the fastening flange (12) at the other end portion of the device (1), that each part of the lead- -through member (9) situated between two attachment holes (6) has two lead-through and sealing portions (10) provi¬ ded beside each other, while the other parts of the lead- through member (9) has a plurality of rows of three or four lead-through and sealing portions (10) disposed beside each other. 8. Device according to any preceding claim, c h a ¬ r a c t e r i z e d i n that the lead-through member (9) and the fastening flange (12) integral therewith are made of an elastic thermoplast.

Inventors: NILSSON BO ANDERS, NILSSON LARS-GOESTA, NILSSON, BO, ANDERS, NILSSON, LARS-GOESTA
Applicants: NILSSON LARS GOESTA, NILSSON, LARS-GOESTA
Application year: 1989
Main classification: H02G3
IPC codes: H02G3