| 摘要 |
730,445. Making pipe elbows. NORTHERN INDIANA BRASS CO. Aug. 4, 1953 [Dec. 8, 1952], No. 21456/53. Classes 83 (2) and 83 (4). Stamping; bending.-A method of forming elbows from tubular stock open at both ends comprises forcing a tubular element endwise partly through a die comprising two straight end portions of circular cross-section connected by an arcuately-curved portion and partly through an annular space defined by the curved portion and a partially spherical member located therein, and thereafter withdrawing the partially spherical member through the end part of the tubular element, which has been forced beyond the annular space, to smooth and straighten the said end part. Apparatus comprises a die structure 14 composed of two parts 14a and 14b each provided with a recess 16 shaped to form, when the parts are assembled, cylindrical portions 18 and 20 normal to one another and joined by an arcuate portion 22. The cylindrical portion 18 accommodates a plunger 24 the lower end of which i s reduced in diameter and has a spherically concave projecting portion 34. Associated with the die 14 and plunger 24 is a mandrel 36 having a spherically-shaped head 38 and a reduced neck portion 40. The mandrel is supported by a pin 42 extending through the mandrel and into openings on side-plates 44. The threaded end 52 of the mandrel extends through a transverse plate 48 and a nut 62, having spherical surfaces 64, seats in complementary surfaces in the plate 48. The diesupporting structure also includes a plate 54 attached to the side-plates 44 and the bed 10 of the press and a yoke member 57 bolted to the base 12. A pin 61 spans the plates 44 and supports the mandrel when the pin 42 is withdrawn. The headed end 38 of the mandrel is adjusted by means of an abutment screw 66. In operation, a tubular blank 70 (Fig. 3) having bevelled ends 72, 74 is positioned in the cylindrical portion 18 of the die and the hydraulic plunger 24 actuated to force one end portion of the blank around the curved portion of the die passage and through the annular space defined by the mandrel head and said curved portion. To complete the elbow the pin 42 is removed and the mandrel withdrawn from the die passage by rotating the nut 62, the mandrel head passing through the distorted end of the elbow and shaping said end to its final form Thereafter, the die is split and the completed elbow removed. Automatic means may be provided for locating and moving the mandrel to speed up production. |
