FIELD OF THE INVENTION
The present invention relates to a slide fastener with a sealing profile suitable for civilian and military uses which requires an Airtight and Fluid tight application such as airtight containers, tents, etc.
BACKGROUND OF THE INVENTION AND PRIOR ART
Airtight and Fluid tight slide fasteners are known in prior art and are used in protective garment industry. Three types of design of such fasteners are known , one with individual metal teeth, the second with individual moulded plastic teeth and the third with continuous coil elements teeth. The fasteners with individual metal or plastic teeth elements , are heavy, run hard and if one tooth fails, the fastener becomes inoperable. Hence the industry prefers continuous coil type due to their high breaking strength, light weight, corrosion resistance and ease of attaching with the garments. As this invention relates to continuous coil elements, design illustrations with individual teeth elements are not given. Few embodiments of this continuous coil elements type Airtight and Fluid tight fastener available in the prior art, are detailed below :
The embodiment as illustrated in US Patent US 2006 / 028 2995 A1, describes " an Airtight and Fluid tight slide fastener, as given in Fig 1.
The Slide fastener includes two elastically water tight strips (10), such as rubber, PU strip. The water tight strips (10) have two water tight layers (11), wherein each upper water layer is individually provided with a tooth row (12) of zipper mechanism which is sewn on the correlative side of the upper water tight layer (11). When the two tooth rows (12) both pass through the slider of the zipper, the teeth get coupled and thus presses the water tight strip (10) with a cohesive force to form a water tight seal (13). The upper flange (15) and lower flange (16) of the slider (14) are on the opposite sides of water tight layers as shown in Fig 1. With such slider design, providing a seal at the top stop needs a very complicated design and also does not provide a good seal

and hence fails at low air pressure. Further as the slider has to press water tight strip to ensure a good seal the running of the slider on the chain is hard.
The second embodiment of continuous coil elements Airtight and Fluid tight Fastener as illustrated in Fig. 2 is based on patent no. US 2014 / 0304954 A1.
The slider fastener has a pair of right and left stringers (20) The tape (21) to which the coupling coil elements (23) are sewn, has a thin polymer coating (22). When the stringers are not joined, the longitudinal edge portions of stringer (25) would be projected beyond the respective coupling elements. When the coupling elements (23) are engaged by pulling together by a slider, the edge portions (25) in overlapped condition, as shown thus providing a seal.
In this embodiment also the upper flange (26) and lower flange (27) of the slider (14) are on the opposite sides of the zipper chain. The extended sealing lips will not match exactly while closing the slide fastener, thus taking inconsistent positions making chain closing inconsistent and the lips also would get worn out due to load on them. Further as the slider runs as both the sides of chain, designing a top stop with proper seal is not possible.
In both the embodiments as detailed above, these coil type fasteners are having sealing profiles or on which the slider runs thus making the slider run hard, wearing of sealing profiles and also the seal at the top stop design at docking end is poor due to poor matching of coil and slider profile, at this position.
Hence there was a need for a continuous coil Airtight and Fluid tight fastener, that has long life without the slider running over sealing profile, that also has a good seal at top and bottom ends of slide fasteners, and improved easiness of the slider running over the chain.

OBJECTS OF THE INVENTION
The basic object of the invention is thus diverted to provide a continuous coil type Airtight and Fluidtight slide fastener that would on one hand provide long life, very high seal strength. Yet another object of the invention is to provide positive seal on top ends of the fastener so that sealing properly is improved.
Various modifications of the disclosed objects, as well as alternate object of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter, it is therefore contemplated that such modifications can be made without departing from the spirit and scope of the present subject matter as defined.
SUMMARY OF THE INVENTION
An Airtight and Fluid tight slide fastener is disclosed, which comprises of a pair of support tapes, and a row of continuous coil coupling elements mounted on each of folded edge of tapes along with longitudinal edge on one side thereof, and water resistant material coated on the other side of the tape and the spaces of the gaps defined in interspace between the folded tapes is filled with a sealing lip profile that prevents entry of air/ fluid.
DETAILED DESCRIPTION OF THE INVENTION
Thus according to the basic aspect of the present invention, the Airtight and Fluidtight slide fastener as shown in Fig 3 comprises of coupling elements (31) of continuous coil type secured to the folded edges (32) of the support tapes (33) coated with thermoplastic resin forming a film (34) on the opposite side of coupling elements where the support tapes are flat. The Thermoplastic gets embedded into the support tapes (33 ) and interspace between the tapes (35). A hair line slit (36) is made or a gap is made during coating itself in the middle of interspace between tape. Over the thermoplastic film thus formed, a thick profile lip seal (37) is formed which bonds well with the film. In this lip profile a gap otherwise referred as gap which is longitudinal cut out portion (38) is formed. An angled hair line slit

(39) is made in the sealing lip profile, marking two lip profiles (43) and (44), so that the chain are separated into two stringers ( 41,42) as shown in Fig 4 to facilitate opening and closing of the chain through the slider (51) as shown in Fig 5 when the chain is opened with the slider, the lip seals are getting separated into two stringer halves (41,42) and when closed with slider (51) these lips in the stringer get close together to form a tight seal, that is kept intact by the tightness of the coupling elements.
Under normal air pressure, the stringers and sealing lips are as shown in Fig. 3. When the excess pressure is applied as shown in Fig 7, the stringers deviate making a small gap (77) in between interspace between the support tapes. Whereas the lip seal (43) presses tightly on the lip seal (44) and tip of (44) presses on the thermoplastic film coated side of supports tape (14) as shown in (76) thus blocking the air flow getting into the slide fastener.
The second embodiment of the present invention has the two profile sealing lips (43) and (44) calibrated to have a pre compression when the two stringers (41) and (42) are joined together by the slider (51). On application of air pressure the compression further increases ensuring tightness of the seal. The gap (38) in the lip profile will not be visible in this case.
Another feature of this invention is the slider (51) with its special design as shown Fig. 6. This slider has a top flange (61) and special shaped cut left and right bottom flanges (62), and the centre bottom flange (64) extended over the diamond of the slider (65). There is a side flange profile (67) to suit the width of interlocking elements width. There is a centre rib (63) to press the centre of the interlocking elements to facilitate joining of the chain. Thus this slider design is made to run on the coupling elements that are on the uncoated side of Airtight fasteners chain. The other side has only the sealing lips (43) and (44), making operation of the slider smooth and at the same time without wearing the lip profile.

Another object of the invention is to provide a good seal at the top end of the fastener when the fastener is fully closed as shown in Fig 8. The continuous chain is cut at the top end where top stop of rectangular shape (81) is formed, along with a thin sealing film (82), closing the remaining gap and also extending towards the closed chain for a short length so that all these areas are sealed providing air tightness. As the top stop design does not yield a complicated profile a consistent good seal at top stop docking end is thus ensured.
Fig. 9 shows another embodiment of the present invention, wherein the thermoplastic film and the sealing profile lips ( 97) are formed on the same side as coupling element (91). The Thermoplastic film (94) is embedded into the support tapes (93) and covers fully the coupling element (91). A hair line slit (96) is made in the interspace between the coupling elements. Over the thermoplastic film thus formed, a thick profile lip seal ( 97) is formed which bonds well with film. In this profile a gap (98) is formed. An angular hair line slit (99) is made so that the chain are separated into two stringers to facilitate opening and closing of the chain by a slider. As the slider runs over the sealing lips, the lips are calibrated to ensure smooth running of slider.
Fig 10 shows yet another embodiment of the present invention, where in the coupling elements (101) are made of plastic injected teeth on continuous length of cord (110), and are stitched ( 111) to the folded edges (102) of the tapes. The Thermoplastic film (104) is embedded into support tapes (103) and into the interspace (105) between the tapes on the remote side of coupling elements where the support tapes are flat. A hair line slit (106) is made or a hair line gap is made during coating itself, in the middle of interspace (105) over the thermoplastic film thus formed, a thick profile lip seal
(107) is formed which bonds well with the film (104). In this lip profile a gap
(108) is formed. An angled hair line slit (109) is made in the sealing lip profile making two lip profiles so that the chain is separated in two stringers to facilitate opening and closing of the chain through slider.

In the embodiments detailed above, though the thin thermoplastic film coating is either tape or coupling element side, depending upon the end applications, the thermoplastic film can also be both on the tape and coupling element side of the fastener.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
The above and other features, aspects and advantages would be better understood with the accompanying figures where ;
Fig 1 illustrates one embodiment of Prior Art coil type Airtight and Fluid tight slide fastener.

Fig 3 illustrates the design of Airtight and Fluid tight fastener chain, as described in the section detailed description of the Invention, para 1
Fig 4 illustrates the shapes of the two stringers and the splitting of lip profiles.
Fig 5 illustrates the Airtight and Fluid tight chain with slider mounted on the chain, showing the advantage of the design feature where the slider runs on the uncoated side support tapes where the coupling elements remain as in the original shape.

Fig 6 illustrates the slider that is designed to work on the Airtight fastener chain
Fig 7 illustrates the function of the air tightness during excess air pressure.
Fig 8 illustrates the top stop design that facilitates a good seal.

Fig 9 illustrates another embodiment of this invention.
Fig 10 illustratesyetanother embodiment of this invention.

As detailed above, the invention in the first embodiment is for air tight and fluid tight fastener. It comprises of a pair of tapes (33) having an inner edge (32) and an outer edge and intermediary space portion (35) therein between the two inner edges (32) of the two tapes (33), and further the outer edge means an edge located at opposite side of inner edge means and located at a side away from the opposing tape. It includes a row of coupling elements (31) secured to the folded inner edge (32) regions of the respective tapes (33), forming a fastener chain. It also has a slider (51) for taking said rows of coupling elements into and out of engagement with each other, thereby separating the chain into two stringers (41,42). An unitary thermoplastics seal member extends across the surface of the tapes forming a first unitary seal member film portion (34) on the said tapes (33). Further the said seal member film portion (34) having a width substantially coextensive relation with the width of the said two tapes (33) and further the said seal member extending into the intermediate space (35) between the inner edges (32) of the pair of tapes (33) to form a thickened sealing member. The said seal member having a slit (36) in the said thickened intermediary space (35) and extending onto the film portion (34), thereby enabling engagement and disengagement of coupling elements (31) with respect to each other with the said slider. The elastically deformable sealing lip means (37) having first and second sides superimposed and secured onto the free surface of the sealing member film portion (34), and further said sealing lip means (37) having an angular slit (39) thus separating the sealing lip means (37) into two lip profiles (43) and (44) which join together to form a seal when coupling elements (31) in the two stringers (41) and (42) are engaged with the said slider (51).
In another embodiment the coextensive relation of the film portion with the tapes may be partial or whole width of the tapes.

In another embodiment the said sealing lip means (37) having a gap (38) which is longitudinally profiled on its side proximate to film portion (34).
In another embodiment the said surface of the tapes with the thermoplastic seal member is remote from the said coupling elements.
In another embodiment the said surface of the tapes with the thermoplastic seal member is proximate to the said coupling elements.
In the above description the inner edge means an edge located at a side close to the opposing tape.
In the above description the outer edge means and edge located at opposite side of inner edge and located at a side away from the opposing tape.
The invention has disclosed details for the purpose of understanding the invention and all variants as obvious to the skilled person is part of this invention. The applicant relies on the provisional specification and the drawings accompanying the provisional specification.

1. An air tight and fluid tight fastener comprising of :-
a. a pair of tapes (33) having an inner edge (32) and an outer edge and
intermediary space portion (35) therein between the two inner edges
(32) of the two tapes (33), and further the outer edge means an edge
located at opposite side of inner edge means and located at a side
away from the opposing tape.
b. a row of coupling elements (31) secured to the folded inner edge (32)
regions of the respective tapes (33), forming a fastener chain,
c. a slider (51) for taking said rows of coupling elements into and out of
engagement with each other, thereby separating the chain into two
stringers (41,42),
d. an unitary thermoplastics seal member extending across the surface of
the tapes forming a first unitary seal member film portion (34) on the
said tapes (33),
e. further the said seal member film portion (34) having a width
substantially coextensive relation with the width of the said two
tapes (33) and further the said seal member extending into the
intermediate space (35) between the inner edges (32) of the pair of
tapes (33) to form a thickened sealing member,
f. further the said seal member having a slit (36) in the said thickened
intermediary space (35) and extending onto the film portion (34),
thereby enabling engagement and disengagement of coupling elements
(31) with respect to each other with the said slider,
g. an elastically deformable sealing lip means (37) having first and second
sides superimposed and secured onto the free surface of the sealing
member film portion (34), and
h. further said sealing lip means (37) having an angular slit (39) thus separating the sealing lip means (37) into two lip profiles (43) and (44)

which join together to form a seal when coupling elements (31) in the two stringers (41) and (42) are engaged with the said slider (51).
2. The fastener as claimed in claim 1, wherein further the said sealing lip means (37) having a gap (38) which is longitudinally profiled on its side proximate to film portion (34).
3. The fastener as claimed in claim 1, wherein the said surface of the tapes with the thermoplastic seal member is remote from the said coupling elements.
4. The fastener as claimed in claim 1, wherein the said surface of the tapes with the thermoplastic seal member is proximate to the said coupling elements.
5. The fastener as claimed in claim 1, wherein the inner edge means an edge located at a side close to the opposing tape.
6. The fastener as claimed in claim 1, wherein the outer edge means and edge located at opposite side of inner edge and located at a side away from the opposing tape.
7. The fastener as claimed in claim 1, wherein the co-extensive relation of the film portion (34) with the width of the said two tapes (33) means the width is total width of the said two tapes.
8. The fastener as claimed in claim 1, wherein the co-extensive relation of the film portion (34) with the width of the said two tapes (33) means the width is partial width of the said two tapes.