NZ329091A

NZ329091A - Plastic band, for the production of helical wound pipes, having complementary ribs and grooves on opposite edges

Info

Publication number: NZ329091A
Application number: NZ329091A
Authority: NZ
Inventors: Rudolf Zimmerli
Original assignee: Nueva Ag
Priority date: 1996-11-05
Filing date: 1997-11-03
Publication date: 1998-08-26
Also published as: AU739397B2; AR013593A1; ID17298A; ZA975939B; CN1181305A; MX9701269A; KR19980041880A; KR100486314B1; HN1997000008A; BR9705176A; IL121390A0; PA8427401A1; AU2560697A; PE46598A1; MY130977A; IL121390A; CO4560566A1; CN1079727C; SV1997000019A

Description

<div class="application article clearfix" id="description"> New Zealand No. 329091 International No. PCT/ TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 05.11.1996; Complete Specification Filed: 03.11.1997 Classification:^) B29D23/00; F16L11/16,24 Publication date: 26 August 1998 Journal No.: 1431 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Plastic band for the production of helical wound pipes Name, address and nationality of applicant(s) as in international application form: NUEVA AG, a Swiss corporation of Hauptstrasse 10, CH-8872 Weesen, Switzerland 0 3 MOV 1997 Patents Form No. 5 Our Ref: DT208429 Patents Act 1953 COMPLETE SPECIFICATION PLASTIC BAND FOR THE PRODUCTION OF HELICAL WOUND PIPES We, NUEVA AG, a Swiss corporation of Hauptstrasse 10, Ch-8872 Weesen, Switzerland hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: PT05A14-892 1 (followed by pages 1a) 329091 Plastic Band for the Production of Helical Wound Pipes The present invention relates to a plastic band for the production of helical wound pipes, with coupling ribs having enlarged heads and with at least partly undercut grooves extending along the edges of the bands for forming a coupling between adjacent band edges, whereby ribs and grooves at both band edges are designed complimentary relative to each other. The production of wound pipes by means of plastic bands of the kind mentioned above is generally known. Independently from a using of single or double walled profiles or bands, resp., the coupling between adjacent band edges forms the weak region of such pipes. This problem comes to be a risk factor specifically by pipes which in operation are subjected to pressure and at pipes which are entrenched in the ground. The above mentioned snap - connections between adjacent band edges were suitable for extraordinary elastic band materials and accordingly specifically for the production of insulating pipes for existing pipe lines or electrical cables. In case of higher stresses the coupling area had as a rule to be provided with an additional protective coating or an additional closure band. Object of the present invention has now been to provide a plastic band for the production of helical wound pipes of the kind defined above, which ensures by a simple, low cost [(followed by page 2) 3290 the kind defined above, which ensures by a simple, low cost design a problem - less coupling between the band edges at a large variety of conditions. This object has been met in accordance with the invention at a plastic band of the kind described by the specific features in accordance with the characterizing portion of claim 1. Specific embodiments of the subject of the invention are defined in the dependent claims. The core of the invention lies in the design of the coupling structure with the inner ribs which are freely elasticity moveable during a snapping together, which ribs can be arranged without any problems within the thickness of the band. The coupling is specifically suitable also for the winding of pipes which are subject to high inner or outer pressures. Hereinafter, the invention will be explained more in detail based on a embodiment illustrated in the drawing, wherein: Fig. 1 is a cross section through a plastic band structured in accordance with the invention; Fig. 2 is a section through the area of the connection (coupling) between two adjacent band edges; and Fig. 3 illustrates a band edge on a somewhat enlarged scale. 3290 - 3 - Fig. 1 of the drawing depicts a cross section through a plastic band. Fig. 2 of the drawing illustrates two adjacent, complimentary designed band edges 1, 2 after having been joined during the winding of a pipe. The two band edges 1, 2 are formed by the parallel edges of a single plastic band of which the edges are designed in a complimentary manner, and which are joined together in from of a snap coupling for the forming of a pipe. Fig. 3 depicts the design of one of the two band edges 1 on a enlarged scale (the second band edge 2 located at the left side is designed in a complimentary mirrored manner). The band is designed as a hollow profile or double - walled band,. resp., having the band walls 3, 4 and .featur.es.-e.g. a thickness of 12-15 mm. Outer and inner ribs 5 and 6, resp. and outer and an inner grooves 7 and 8, resp. are formed along the edge of the band. The front surface 9 extends from the band surface 10 slightly inclined inwards (wedge surface) and the groove edge 8' is designed complimentary thereto, whereby the front surface 9' of the band edge to be coupled thereto comes to abut the surface 8'. The groove 7 is formed between the rib flanks 5' and 6', while the second groove 8 is located between the groove flank 6" and the surface 8'. The groove 8 has a cross section which corresponds substantially to the cross section of the complimentary outer rib of the adjoining band edge (small clearance, only). 329 - 4 - Different, however, is the groove 7 which has to receive the coxaplimentary inner rib of the adjoining band edge of which groove the width is substantially larger than the thickness of the rib to be received (see Fig. 1). When joining the two band edges 1,2 the inner ribs can elastically yield during the snapping of the rib heads of the ribs 6 into the grooves 8, and after the joining process they can again move back into the normal position. Such as can be clearly seen in the drawing, the ribs 5, 6 comprise broadened heads 51 ' T(, 6'' 1 facing the grooves 7 and 8, resp., which engage under each other during the joining, i.e. they form a undercut of the grooves 7 and 8,resp. As illustrated in Fig. 1, elastomeric sealing ledges 11, 12 can be foreseen on the rib heads 511', 61,1 or on the groove bottoms located directly opposite thereof such to form a leakage tight connection. </div>

Claims

<div class="application article clearfix printTableText" id="claims"> - 5 - Vt: •4 Patent claims 1. Plastic band for the production of helical wound pipes, with coupling ribs having enlarged heads and with at least partly undercut grooves extending along the edges of the band for forming a coupling between adjacent band edges, whereby ribs and grooves at both band edges are designed complimentary relative to each other,' characterized in that at each band edge two respective parallel ribs and grooves are foreseen, of which the grooves located at the inside have a cross section which corresponds substantially to the cross section of the outer ribs which form the band edge, while the respective second, inner rib features a thickness which is less than the width of the outer groove formed between the two ribs of each band edge, so that when joining adjacent band edges both ribs which are located inside can elastically deform unimpeded in a direction towards each other when their heads snap into the grooves. 2. Plastic band according to claim 1, characterized in that the outer ribs which form the outer band edge comprise a front surface which is chamfered from the surface of the band slightly wedge like toward the inside. 3. Plastic band according to claim 1 or 2, characterized in that the ribs and grooves which are foreseen for forming the coupling are located at the band edges completely within the thickness of the band. INTELLECTUAL t-'F.ji OrTict" OF N.z. 0 5 J JN 1SC3 R E C E! \f c n - 6 - 2900 4. Plastic band according to one of the claims 1-3, characterized in that the band describing a double walled profile is designed in part as a hollow profile. 5. Plastic band according to one of the claims 1-4, characterized in that elastomeric sealing means are foreseen on heads of ribs or on bottoms of grooves located in the coupled state opposite thereof. 6. Plastic band according to one of the claims

1-5, characterized in that the outer groove is formed by the flanks of the two ribs and the one flank of the inner groove is formed by a flank of the inner rib, whereby the heads of the ribs on one side project in this manner over the ribs. 7. A plastic band for the production of a helical wound pipe substantially as herein described with reference to the accompanying drawings. Nueva AG By Its Attorneys I BALDWIN SON and CAREY </div>