GB539167A - Improvements in or relating to the manufacture of hollow articles - Google Patents

Abstract

539,167. Making pipe tees &c. WATSON, F. (W.S.A., Inc.). April 12, 1940, No. 6651. [Classes 83 (ii) and 83 (iv)] Stamping.-Hollow articles such as pipe tees, crosses, elbows and Y-s are made in copper, aluminium, mild steel &c. by forming a closed ended tube from a blanked out disc and converting into the required form by internal fluid pressure as described in Specification 463,651. The cupped blank is formed with a thickened end 14, Fig. 2, and a short parallel section of the same thickness tapering uniformly at 16a to a thinner parallel portion 16b. The blank is placed in a closely fitting twopart die 18, is substantially filled with liquid 44, and is acted on by a punch shaped according to the taper of blank. Excess liquid passes by a central bore 40 to a side duct 42 both formed in the pilot section 32 of the punch. Considerable fluid pressure is built up by the time the shoulder 36 contacts the end of the blank and the combined end pressure and internal pressure start expansion in the lateral branches 22, 24. The expansion is completed by the use of further punches with shorter pilots to complete the stamping as in Fig. 9. The finished fitting is of substantially uniform thickness except for a slight thickening at and depending on the magnitude of the radiusing 28. The squared ends are removed as by sawing and the ends may be expanded to enable soldered push-in joints to be made. The ends need not be completely squared before removal.