Study of a multiple connector for fluid piping (17 February 1966)

In this document

The problem posed

The note opens with an observation: hydraulic and pneumatic controls "are developing more and more", and tube connections pose problems "identical to those encountered with electrical connections" p. 61. Magès formulates the objective as the hydraulic equivalent of "a multi-pin electrical plug": grouping bundles of tubes so that they are compact, easy to connect, and disconnectable "in a single operation quickly" then "reconnected without risk of error" p. 61.

The solution described

The multiple connector shown (fig. 1, not reproduced in these pages) is presented "as an example" to make five pressure connections plus one pressureless drain circuit p. 61. It includes:

• two parts 1 and 2, onto which the tubes are brazed;
• a pad 3, made of soft metal (aluminium, zinc, lead) or plastic material depending on the pressures, ensuring sealing;
• two sleeves 4 and 5 for tightening the assembly p. 61.

Parts 1 and 2 are "advantageously executed in sintered metal", which eliminates machining despite a complex design; the brazing of the tubes causes copper impregnation which eliminates the porosity of the sintered material p. 61. Protrusions (a, b, c on part 1; d, e on part 2) guarantee that there is "only one assembly position" between the two parts p. 61 — an anti-error detail consistent with the objective stated in the introduction.

Pad 3, circular in shape, has one hole per circuit, each bordered by a sealing bead (except for the drain one); a protuberance f on its periphery, housed between protrusions b and c of part 1, ensures its correct orientation p. 61.

Figures 2 p. 62 and 3 p. 63, plates P.5253-3 and P.5253-4, detail these parts in section: crowns of six holes around a central axis for parts 1 and 2 (marks a, b, c, d, e, 1, 2), and the pierced pad with its protuberance f marked by an arrow p. 62-63.

Context

At Citroën, the multiplication of hydraulic circuits — suspension, braking, power steering, semi-automatic gearbox — on models like the DS led to a proliferation of piping under the body. The comparison that Magès makes with multi-pin electrical connectors is not trivial: it reflects a concern for production and maintenance engineering, at a time when reliability and simplicity of mass assembly were becoming major industrial issues for large manufacturers. In February 1966, Magès had long been deputy head of Super-Control after having been a self-taught technical writer who joined Citroën in 1925 (Draft letter from Paul Magès to Mr. Sarre and interview plan of 11 May 1969); he would remain in this position until his retirement in September 1974 (Photographs of Paul Magès' retirement (1974)).

Archivist's perspective

This document illustrates a lesser-known facet of Paul Magès' work: beyond the major systems he invented (hydropneumatic suspension, pressure regulator), he also seems to have focused on problems of industrial rationalisation, such as here the quick and error-free connection of several hydraulic circuits at once.

The explicit reference to the multi-pin electrical plug p. 61 shows an analogical transposition approach typical of an engineer seeking solutions already validated in a related field. The attention to detail — unique assembly position, forced orientation of the pad — testifies to an attention paid to human error in production, probably nourished by the experience acquired on other hydraulic components in the same file, such as the self-regulating pump with accumulator or the hydraulic pressure regulator, from the same "Hydraulic components" folder.

The date of 17 February 1966, at the bottom of the page p. 61, places this note in the maturity of Magès' career, eight years before his retirement from Citroën in 1974 and well after the first developments of the DS.