GB788150A - Process of and tool for expanding tube ends - Google Patents

Abstract

788,150. Tube expanders and flangers; jointing by tube expanding. BABCOCK & WILCOX, Ltd. (Deutsche Babcock & Wilcox Dampfkesselwerke). Aug. 23, 1956, No. 25737/56. Class 83 (4). A tool for the expanding of a tube end within a tube hole in a plate includes withdrawal means for the forcible pulling-out from inside the tube end of tube expanding means adapted during withdrawal to expand the part of the tube within the hole, the withdrawal means being arranged during withdrawal to operate belling means which effect belling of the free end of the tube. In operation an expanding tool 10 is positioned with a bearing surface 12 engaging a face 5 of a tube plate 3, into a hole 2 in which the end of a tube 1 is to be expanded. An expanding tool mandrel 14, formed with a tapering part 16, is inserted in the tube end, a sleeve-like stop 30 slidable on the cylindrical part of the mandrel 14 being set with its shoulder 34 forwardly of inwardly spring-urged radial plungers 36, and two pairs of expanding members 21 being towards the smaller end of the tapered part 16 of the mandrel 14. One opposed pair of expanding members 21 is staggered axially relative to the other pair and abuts the end of a flared forward part 32 of the stop 30, the four expanding members being held together and on the mandrel by an encircling spring 24. The mandrel 14 is then drawn rearwardly, by hydraulic means, through the body of the expanding tool 10, thus causing the members 21 to move outwardly and into alignment with one another and expand that part of the tube lying immediately outside the plate 3. When a head 15 on the mandrel 14 engages the members 21 the sleeve 30 is moved rearwardly, the plungers 36 riding up over the shoulder 34, together with the expanding members 21 which effect the progressive expansion of that part of the tube 1 lying within the plate 3. As the members 21 approach the face 5 of the plate 3 the flared part 32 of the stop 30 engages inclined surfaces 42 upon eight belling elements 40 to move these elements radially outwards, against springs 41, so that tongues 4 thereon engage and bell outwardly the projecting inner end 4 of the tube 1. The head 15 may be adjustable along the mandrel 14 so that the limit of the outward movement of the expanding members 21 may be adjusted, the members 21 in this case preferably being of piston-ring shaped overlapping design.