IE41825L - Pipe bend - Google Patents

Abstract

1491041 Sheet forming HOECHST AG 21 Oct 1974 [24 Oct 1973] 45382/74 Heading B5A [Also in Division F2] A one-piece plastics pipe-bend 10<SP>1</SP> in the shape of a portion of a hollow ring is open or overlapping along its innermost arc, the pipe bend 10<SP>1</SP> having been formed by bending from an inherently dimensionally stable shell-type body 10 having no re-entrant curves, the pipe bend 10<SP>1</SP> also being inherently dimensionally stable in its bend conformation. Thus through the forms 10, 10<SP>1</SP> may be interconverted, neither form tends to change shape by itself. The shell-type body 10 is made from plastics film by deepdrawing or by blow moulding, the latter yielding a flask-like structure composed of two bodies 10 joined along edges 28. Sufficient stability is conferred upon the body in the bend state 10<SP>1</SP> by thermal treatment of the material in that conformation. Alternatively, a complete torus may be manufactured and then divided into segments 10<SP>1</SP>, which are opened out and heattreated in the shell-type form 10. To increase stability in the bend state 10<SP>1</SP>, a corrugation 14 may be provided to extend along the outermost arc of the ring in the bend conformation 10<SP>1</SP>, or the body 10 may be formed in such a shape that its corresponding bend state 10<SP>1</SP> has at least the mid-portions of its outermost and innermost arcs on different centres of curvature, preferably such that the radial distance between the arcs is less at the mid-portion of the bend than at the ends. Extended areas 12 of the body 10 provide for overlap along the innermost arc of the bend 10<SP>1</SP> where engaging means such as complementary notches or press studs may be utilized. [GB1491041A]