FORM 2


THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A self clamping leak tight LED street light assembly
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
Sathe Mahesh Kashinath and Guruprasad Kuppu Rao, both of Crompton Greaves Ltd, Industrial Design Centre, CG Global R&D Centre. Kanjur (E), Mumbai 400042, Maharashtra, India, both Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:


FIELD OF THE INVENTION
This invention relates to a self clamping leak tight LED street light assembly.
BACKGROUND OF THE INVENTION
A LED (Light Emitting Diode) street light assembly comprises an enclosure and a LED array located in the enclosure. The enclosure comprises a bottom cover and a top cover fitted together by bolting with a sealing gasket located at the contact surfaces between the edges of the bottom and top covers. The requirement of leak tightness or leak proof at the contact surfaces between the edges of the bottom and top covers is very high so as to prevent ingression of foreign particles like dust and water into the enclosure. This requires extensive bolting which is time consuming and leads to productivity loss besides being cumbersome and inconvenient to carry out. During extensive bolting there are chances of failure of the sealing gasket which will lead to leakage of foreign particles into the enclosure. Further, a part of the sealing gasket is invariably exposed and this provides a surface for foreign particles to accumulate on the exposed surface area and eventually travel into the enclosure, especially rain water.
OBJECTS OF THE INVENTION
An object of the invention is to provide a self clamping leak tight LED street light assembly which reduces the assembly time and increases productivity and renders the assembly easy and convenient.
Another object of the invention is to provide a self clamping leak tight LED street light assembly which provides a high level of leak tightness or leak proof.
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DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a self clamping leak tight LED street light assembly comprising an enclosure enclosing a LED array and formed of a bottom cover and a top cover comprising guide means for guiding the bottom cover and top cover towards each other and self clamping means for clamping the bottom cover and top cover against each other and a primary seal and a secondary seal for sealing the contact surfaces between the bottom cover and top cover leak tight, the bottom cover and top cover being further provided with mounting means for mounting the enclosure on a support pole.
The following is a detailed description of the invention with reference to the accompanying drawings, in which:
Fig 1 is an isometric view of a self clamping leak tight LED street light assembly according to an embodiment of the invention;
Fig 2 is an isometric view of the bottom cover of the street light assembly of Fig 1;
Fig 3 is a cut section part isometric view of the bottom cover of Fig 2;
Fig 4 is a bottom isometric view of the top cover of the street light assembly of Fig 1;
Fig 5 is a cut section part isometric view of the top cover of the street light assembly of Fig 1;


Fig 6 is a cut section part isometric view of the street light assembly of Fig 1 with the bottom cover and top cover about to be sealed with the primary sealing gasket; and
Fig 7 is a cut section part isometric view of the street light assembly of Fig 1 with the bottom cover and top cover sealed with both the primary sealing gasket and secondary sealing gasket.
The self clamping leak tight LED street light assembly 1 as illustrated in Figs 1 to 7 of the accompanying drawings comprises an enclosure formed of an oval shaped bottom cover 2 and an oval shaped top cover 3. The bottom cover comprises a closed bottom portion 4 and an endless sidewall 5 extending upwardly from the closed bottom portion. 6 is a transparent window provided in the closed bottom portion of the bottom cover. 7 is a female interlocking member fitted against the inner surface of the sidewall of the bottom cover and having a plurality of teeth 8 across its outer surface protruding above the edge of the sidewall of the bottom cover. The top cover comprises a closed top portion 9 and an endless sidewall 10 projecting down from the closed top portion. 11 is a male interlocking member fitted at the inner surface of the sidewall of the top cover and having a plurality of teeth 12 across its inner surface. The bottom cover also comprises a plurality of longitudinally split inner tubes 13 projecting upwardly from the inner surface of the closed bottom portion thereof. The top cover also comprises a plurality of longitudinally split outer tubes 14 projecting downwardly from the closed top portion thereof corresponding to the inner tubes and adapted to slide over the inner tubes. 15 is a tongue projecting down from the edge of
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the sidewall of the top cover. 16 and 17 are engaging lugs (fluted annular grooves) provided at the outer surfaces of the edges of the bottom cover and top cover, respectively. An LED array (not shown) is fitted at the inner surface of the closed top portion of the top cover corresponding to the transparent window in the closed bottom portion of the bottom cover. The bottom cover and the top cover are assembled together by engaging the longitudinally split outer tubes 14 projecting down from the inner surface of the closed top portion of the top cover over the longitudinally split inner tubes 13 projecting upwardly from the inner surface of the closed bottom portion of the bottom cover and pushing the top cover against the bottom cover. The longitudinally split outer tubes are guided over the longitudinally split inner tubes. Therefore, trie affgnrnent between the tap cover and the bottom cover is maintained while the top cover and bottom cover are closed against each other. The teeth 8 across the outer surface of the female interlocking member protruding above the edge of the sidewall of the bottom cover and the teeth 12 across the inner surface of the male interlocking member are adapted to slide against and interlock with each other. Therefore, when the top cover is closed over and pushed against the bottom cover they also start getting clamped together. When the tongue 15 protruding down from the edge of the sidewall of the top cover is at a distance from the edge of the sidewall of the bottom cover a primary sealing gasket 18 is located against the edge of the sidewall of the bottom cover and the top cover is further pushed against the bottom cover. The tongue 15 at the edge of the sidewall of the top cover sinks into the primary sealing gasket and the tongue together with the primary sealing gasket surrounding it forms a primary seal between the mating edges of the sidewalls of the bottom and top covers. By then the teeth of the female and male interlocking members would have fully engaged against one another and self clamped the bottom
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and top covers. A secondary sealing gasket 19 is disposed over the exposed surface area of the primary sealing gasket and engaged over the engaging lugs 16 and 7 at the outer surfaces of the edges of the sidewalls of the bottom and top covers so as to provide a secondary seal at the contact surface between the edges of the sidewalls of the bottom and top covers. The mating surface area between the interlocking members 7 and 12 also provides a seal at the contact surface between the sidewalls of the bottom and top covers. Therefore, the top and bottom covers are self clamped without bolting and the contact surface between the bottom and top covers are completely covered and sealed very effectively against leakage both by the primary seal and the secondary seal and also by the interlocking members. 20 is an inwardly extending open ended tubular extension at the mounting end of the top cover and 21 is a corresponding open slot in the bottom cover at the mounting end thereof for accommodating the tubular extension. The street light assembly of the invention is mounted on a support pole (not shown) by engaging a lateral extension on the support pole in the tubular extension at the mounting end of the top cover. Because of the slitted nature of the inner and outer tubes 13 and 14 air entrapment within the tubes is prevented. Air entrapment within the inner and outer tubes will lead to development of hot spots within the enclosure and adversely affect the performance of the light assembly. Preferably, the top cover and the bottom cover and the respective inner tubes and outer tubes are aluminium die cast and the male and female interlocking members are moulded thermoplastics selected from high impact polystyrene or polycarbonate. Preferably the primary sealing gasket is made of nitrile or silicon rubber and the secondary sealing gasket is made of moulded plastics like teflon or nylon.
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It is understood that the enclosure will also contain LED driver box and that the LED array and LED driver box may be located in the same compartment or different compartments. It is also understood that the lead wires from the enclosure should have appropriate sealing means.
According to the invention bolting of the bottom and top covers of the enclosure has been eliminated and the bottom and top covers are self clamping. Therefore, assembling of the street light assembly of the invention is easy and convenient and can be carried out within reduced time so as to increase productivity. The contact surfaces between the bottom and top covers are effectively sealed against leakage both by the primary seal and the secondary seal. Further, the primary seal is fully covered by the secondary seal. As a result, the contact surfaces between the edges of the sidewalls of the bottom and top covers are effectively and positively sealed and ingression of foreign particles into the enclosure is completely prevented. Even if the primary seal fails still the secondary seal will provide protection against leakage. Further the abutting and overlapping surfaces of the interlocking members also provide protection against leakage and internal thermal shocks.
The above embodirnent of the invention is by way of example and should not be construed and understood to be limiting the scope thereof. The guiding means, self clamping means and the primary and secondary sealing arrangements can be of different construction / configuration. The mounting means also can be of a different construction / configuration. The top cover and the bottom cover can be of a different construction / configuration and need not be oval shaped. Both the top cover and the bottom cover and the male and female interlocking members can be made of different
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materials. Both the primary sealing gasket and the secondary sealing gasket also can be made of different materials. Embodiments comprising such variations of the invention are obvious to those skilled in the art and are to be construed and understood to be within the scope of the invention.
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We claim :
1. A self clamping leak tight LED street light assembly comprising an enclosure enclosing a LED array and formed of a bottom cover and a top cover comprising guide means for guiding the bottom cover and top cover towards each other and self clamping means for clamping the bottom cover and top cover against each other and a primary seal and a secondary seal for sealing the contact surfaces between the bottom cover and top cover leak tight, the bottom cover and top cover being further provided with mounting means for mounting the enclosure on a support pole.
2. The self clamping LED street light assembly as claimed in claim 1, wherein the bottom cover comprises a closed bottom portion and an endless sidewall extending upwardly from the closed bottom portion and the top cover comprises closed top portion and an endless sidewall projecting downwardly from the closed top portion, the guide means comprises a plurality of longitudinally split inner tubes projecting upwardly from the inner surface of the closed bottom portion of the bottom cover and a plurality of longitudinally split outer tubes projecting downwardly from the closed top portion of the top cover corresponding to the inner tubes and adapted to slide fit over the inner tubes, the self clamping means comprises a female interlocking member fitted against the inner surface of the sidewall of the bottom cover and having a plurality of teeth across its outer surface protruding above the edge of the sidewall of the bottom cover and a male interlocking member fitted at the inner surface of the sidewall of the top cover and having a plurality of teeth across its inner surface adapted to slide against and interlock with the teeth on the outer surface of the female interlocking member, the primary seal comprises a tongue projecting down from the edge of the sidewall of the top cover and a first sealing gasket located
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at the edge of the sidewall of the bottom cover, the tongue being adapted to engage against and sink into the first sealing gasket and the secondary seal comprises a second sealing gasket located over the exposed surface of the first sealing gasket and engage against engaging lugs provided at the outer surfaces of the edges of the bottom cover and top cover and the mounting means comprises an inwardly extending open ended tubular extension at the mounting end of the top cover and a corresponding open slot for the tubular extension provided at the mounting end of the bottom cover.
3. The self clamping LED street light assembly as claimed in claim 2, wherein the top cover and the bottom cover and the respective inner tubes and outer tubes are aluminium die cast and the male and female interlocking members are moulded thermoplastics.
4. The self clamping LED street light asssembly as claimed in claim 3. wherein the moulded thermoplastics comprises high impact polystyrene or polycarbonate.
5. The self clamping LED street light assembly as claimed in any one of claims 2 to 4, wherein the primary sealing gasket is made of nitrile or silicon rubber and the secondary sealing gasket is made of moulded plastics like teflon or nylon.
6. The self clamping LED street light assembly as claimed in anyone of claims 1 to 4, wherein the bottom cover and top cover are oval shaped.
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7. The self clamping LED street light assembly as claimed in any one of claims 1
to 6, wherein the LED array is fitted at the inner surface of the closed top portion of the top cover and the closed bottom portion of the bottom cover comprises a transparent window corresponding to the LED array.
Dated this 4th day of February 2009
(Jose M A) ofKhaitan&Co Agent for the Applicants
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