BS M 59:1986 pdf free download.British Standard Aerospace Series: Specification for
Interface of metric couplings for aerospace fluid systems [ISO title: Aerospace construction — Fluid systems — Interface of metric couplings].
1 Scope and field of application
BS M 59 defines the geometry of the interface of the removable couplings fo the aircraft fluid systems, with the possibility that the connection with the pipe of each one of the connecting elements be of different design.
BS M 59 fixes the dimensions providing for the Interchangeability of the mate and female elements and of the nut used for the connection.
The dimensions are a definition of the maximum volume of the male fitting.
2 Reference
ISO 5855/1, Aerospace construction — MJ thread — Pan 1:
Basic profile.
3 Coupling assembly and sealing principle
The coupling comprises throe elements:
A female element Including a frustum with a cone anglo equal to 24° In which the male element comes into contact to provide the sealing. The contact line Is a circle with a theoretical diameter E.
A male element, included inside a shell, with a torical/or spherical area extended by two tangential frustums on which the female element comes into contact to provide for the sealing. This contact line Is a circle with a theoretical diameter E.
A nut providing for the assembly of the male and female elements of the coupling.
Pornt a ongin at E/2 from the XX, axis.
Point b = point located at a distance N from point a on the perpendicular to the line tilted 120 relativo4y to XX’ and passing through a.
Point c = located at 8/2 from the XX axis and at P from a.
Une cd tangent drawn from c to the arc of circle with center b and radius N.
Line of — tangent tilted 12° 50 on the arc of circle of centet b and of radius N. The point of tangency thus ob tamed is designated a.