GB1277026A - Improvements in and relating to pipe couplings - Google Patents

Abstract

1277026 Making grommets; forging ARMSTRONG PATENTS CO Ltd 25 Sept 1969 [25 Sept 1968] 45467/68 Headings B3A and B3H [Also in Division F2] An olive 10 comprises a tubular sleeve having tapering, outwardly directed, frusto-conical surfaces 12, 14 for coacting with frusto-conical surfaces 50, 56 of a body member 36 and nut 40 respectively. Adjacent each end of the olive and inwardly spaced therefrom is a single radially inwardly projecting land 32, a pipe 48 being slidingly engageable in these lands when the olive is undeformed. Upon tightening the clamping nut (a) the land at the end of the olive coacting with the long taper 50 of the body bites into the pipe and the end 34 of the olive is bent over to contact the pipe wall (b) the land at the end of the olive coacting with the steep taper 56 of the nut is pressed into contact with the pipe wall (but does not appreciably bite into it), and the end 34 is again pressed into contact with the tube wall. As a result of the action of the steep taper 56 of the nut it is easy to determine when the joint is tight as the nut because suddenly more difficult to turn when the end 34 contacts the pipe wall. Preferably the angle between the external surface 14 of the olive and the taper 50 of the body is between 5 and 15 degrees, while the corresponding angle between tapers 12 and 56 approximates to 45 degrees and exceeds 15 degrees. The olive is preferably centro symmetric and may be machined from tubular stock, but according to one aspect of the invention is made by die stamping (after the machining or otherwise forming the external tapers 12, 14). Two die halves (18, 20) (Fig. 2, not shown) are formed with through holes (22, 24) and are adapted to meet in a radial plane of the olive such that the through holes and the bore of the olive are coaxial, the olive being held in conical recesses in the die halves complementary to tapers 12, 14. A punch is driven in to the bore of the olive via each through hole and displaces material to form the land. There may be two punches applied simultaneously from each end or one punch applied successively to each end. The lands formed by punching have radially planar outwardly facing surfaces and rounded inwardly facing surfaces (Fig. 3, not shown). If the olive is made by machining each land may have a radially planar outwardly facing surface, a right cylindrical axially extending surface and a frusto-conical inwardly facing surface.