METHOD OF JOINING SYNTHETIC-RESIN TUBES
First Claim
1. IN A METHOD OF FORMING A JOINT BETWEEEN TUBE AND A SLEEVE OF THERMOPLASTIC SYNTHETIC RESIN, ESPECIALLY HARD POLYVINYL CHLORIDE, IN WHICH THE SLEEVE IS HEAT-SHRUNK ONTO A PORTION OF THE TUBE SURROUNDED BY THE SLEEVE AFTER THE TUBE GAS BEEN INSERTED INTO THE SLEEVE WITH CLEARANCE THEREBETWEEN, THE IMPROVEMENT WHEREIN:
- AT LEAST SAID SLEEVE IS FORMED WITH A CIRCUMFERENTIAL INWARDLY OPEN CORRUGATION DEFINING AN ANNULAR CHAMBER AROUND THE TUBE AT SAID PORTION;
THE HEAT REQUIRED FOR SHARINKING SAID SLEEVE ONTO SAID TUBE IS SUPPLIED BY INJECTING A HEATED FLOWABLE MOLTEN ADHESIVE INTO SAID CHAMBER UNDER PRESSURE, AND SAID ADHESIVE A COMPRESSED AGAINST SAID TUBE BY SAID SLEEVE UPON THE SHRINKAGE THEREOF.
0 Assignments
0 Petitions
Accused Products
Abstract
The spigot end of a tube made of hard polyvinyl-chloride (PVC) is fit into the heat-shrinkable bell end of a similar tube. A hot thermally-activatable adhesive is injected into the space between the bell and spigot so that it heats and shrinks the bell, causing it to compress and distribute the adhesive mass throughout the joint. The bell is formed with a circumferential bulge forming an inwardly opening circumferential recess into which the adhesive mass is injected through at least one radially opening hole. The mass of adhesive in this groove serves as a hot reservoir of glue during shrinking and distribution.
-
Citations
2 Claims
-
1. IN A METHOD OF FORMING A JOINT BETWEEEN TUBE AND A SLEEVE OF THERMOPLASTIC SYNTHETIC RESIN, ESPECIALLY HARD POLYVINYL CHLORIDE, IN WHICH THE SLEEVE IS HEAT-SHRUNK ONTO A PORTION OF THE TUBE SURROUNDED BY THE SLEEVE AFTER THE TUBE GAS BEEN INSERTED INTO THE SLEEVE WITH CLEARANCE THEREBETWEEN, THE IMPROVEMENT WHEREIN:
- AT LEAST SAID SLEEVE IS FORMED WITH A CIRCUMFERENTIAL INWARDLY OPEN CORRUGATION DEFINING AN ANNULAR CHAMBER AROUND THE TUBE AT SAID PORTION;
THE HEAT REQUIRED FOR SHARINKING SAID SLEEVE ONTO SAID TUBE IS SUPPLIED BY INJECTING A HEATED FLOWABLE MOLTEN ADHESIVE INTO SAID CHAMBER UNDER PRESSURE, AND SAID ADHESIVE A COMPRESSED AGAINST SAID TUBE BY SAID SLEEVE UPON THE SHRINKAGE THEREOF.
- AT LEAST SAID SLEEVE IS FORMED WITH A CIRCUMFERENTIAL INWARDLY OPEN CORRUGATION DEFINING AN ANNULAR CHAMBER AROUND THE TUBE AT SAID PORTION;
-
2. The improvement defined in claim 1 wherein said adhesive is a mixture of a polyamide in a proportion by weight of 95 to 70 percent with an aromatic binder with active hydroxyl groups in a proportion by weight of 5 to 30 percent.
Specification