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US 4,083,070 AGranted
Inflatable liferafts of thermoplastic material and methods for their manufacture
AssigneeRFD Inflatables Limited
InventorMichael Dudley Martin
Life of this patent
Estimating the term…
Abstract
A method of making an inflatable liferaft from thermoplastic sheet material, wherein the thermoplastic sheet material which is to form a floor of the liferaft is heat welded around the periphery of the floor to the thermoplastic sheet material which is to form a peripheral inflatable buoyancy tube of the liferaft, after which edges of the material which is to form the tube are joined by heat welding to close the tube along its longitudinal extent.
Claims7
A method of making an inflatable polygonally shaped liferaft comprising the steps of
- fabricating a polygonally shaped liferaft floor from flexible thermoplastic sheet material,
- fabricating a buoyancy tube sub-assembly by joining a plurality of panels of flexible thermoplastic sheet material in series at the transverse edges of adjacent panels in lipless, non-overlapping, end-to-end, abutting relationship by heat welding adjoining strips of thermoplastic material disposed contiguous with the portions of the surfaces of the adjacent panels proximate to the transverse edges thereof and which are to be at the interior of the buoyancy tube sub-assembly, the strips overlapping the transverse edges of adjacent panels, whereby the panels are joined to form an endless loop, there being a single panel for each side of the polygonal shape of the liferaft,
- positioning the buoyancy tube sub-assembly with one of the longitudinal edges of each of the panels disposed outwardly of the floor periphery and with a portion of each panel adjacent the one of the longitudinal edges overlying the periphery of the floor,
- inserting a V-shaped strip of material consisting of thermoplastic material only on the outer surfaces of the strip, the V-shaped strip being inserted between the portion of each panel adjacent to the one of the longitudinal edges and the periphery of the floor, the apex of the V-shaped strip extending outwardly with respect to the periphery of the floor,
- heat welding the upper surface of the periphery of the floor to the lower outer surface of each of the V-shaped strips and heat welding of outer surface of the portion of each of the panels of the buoyancy tube sub-assembly adjacent the one longitudinal edge thereof to the upper outer surface of each of the V-shaped strips, the inner surface of each of the V-shaped strips remaining free of one another after the heat welding to enable each V-shaped strip to be hinged about the apex thereof, thereby creating a heat welded seam between the floor periphery and the buoyancy tube sub-assembly,
- positioning the other longitudinal edge of each of the panels in an overlying relationship with the one longitudinal edge of each of the panels,
- inserting a V-shaped strip of material consisting of thermoplastic material only on the outer surfaces of the strip between the portions of the inner surfaces of each panel adjacent the one and other longitudinal edges thereof, the apex of each V-shaped strip extending toward the longitudinal edges of each panel, the inner surfaces of each panel immediately adjacent the longitudinal edges thereof being contiguous to one another,
- heat welding the inner surfaces of each panel immediately adjacent the longitudinal edges thereof to one another and heat welding the inner surface of each panel to the outer surfaces of the V-shaped strip disposed therebetween, the inner surfaces of each V-shaped strip being free of one another after the heat welding to enable the V-shaped strip to be hinged about the apex thereof, the heat welding of the panels adjacent the longitudinal edges closing the buoyancy tube sub-assembly along its longitudinal extent and forming a single, uninterrupted, longitudinally-extending heat welded seam about the buoyancy tube sub-assembly, said single seam extending around the outboard side of the liferaft, whereby seams on the inboard side of the buoyancy tube sub-assembly used to fabricate the buoyancy tube sub-assembly consist only of lipless, heat welded transverse seams.
5 more elements
An inflatable liferaft comprising, a polygonally shaped liferaft floor made from flexible thermoplastic sheet material.
- A buoyancy tube sub-assembly having a plurality of panels of flexible thermoplastic sheet material disposed in series at the transverse edges of adjacent panels in lipless, non-overlapping, end-to-end, abutting relationship, and adjoining strips of thermoplastic material being disposed contiguous with the portions of the surfaces of the adjacent panels proximate to the transverse edges thereof and which are to be at the interior of the buoyancy tube sub-assembly, the strips overlapping the transverse edges of adjacent panels, the strips being heat welded to the adjacent panel, whereby the panels are joined to form an endless loop, there being a single panel for each side of the polygonal shape of the liferaft, the buoyancy tube sub-assembly being disposed with one of the longitudinal edges of each of the panels extending outwardly of the floor periphery and with a portion of each panel adjacent the one of the longitudinal edges overlying the periphery of the floor,
- a V-shaped strip of material consisting of thermoplastic material only on the outer surfaces of the strip, the V-shaped strip being disposed between the portion of each panel adjacent to the one of the longitudinal edges and the periphery of the floor, the apex of the V-shaped strip extending outwardly with respect to the periphery of the floor, the upper surface of the periphery of the floor being heat welded to the lower outer surface of each of the V-shaped strips, the outer surface of the portion of each of the panels of the buoyancy tube sub-assembly adjacent the one longitudinal edge thereof being heat welded to the upper outer surface of the V-shaped strips, the inner surfaces of each of the V-shaped strips remaining free of one another after the heat welding to enable each V-shaped strip to be hinged about the apex thereof, thereby creating a heat welded seam between the floor periphery and the buoyancy tube sub-assembly, the other longitudinal edge of each of the panels being disposed in an overlying relationship with the one longitudinal edge of each of the panels,
- a V-shaped strip of material consisting of thermoplastic material only on the outer surfaces of the strip being disposed between the portions of the inner surfaces of each panel adjacent the longitudinal edges thereof, the apex of each V-shaped strip extending toward the longitudinal edges of each panel, the inner surfaces of each panel immediately adjacent the longitudinal edges thereof being contiguous to one another, the inner surfaces of each panel immediately adjacent the longitudinal edges thereof being heat welded to one another, the inner surface of each panel being heat welded to the outer surfaces of the V-shaped strip disposed therebetween, the inner surfaces of each V-shaped strip being free of one another after the heat welding to enable the V-shaped strip to be hinged about the apex thereof, the heat welding of the panels adjacent the longitudinal edges closing the buoyancy tube sub-assembly along its longitudinal extend and forming a single, uninterrupted, longitudinally-extending heat welded seam about the buoyancy tube sub-assembly, said single seam extending around the outboard side of the liferaft;
- whereby seams on the inboard side of the buoyancy tube sub-assembly used to form the endless loop consist only of lipless, heat welded transverse seams.
1 more element
Dependencies are inferred from the claim text.