Annotated technical sketch sheets “E” — sketches of hydraulic components

In this document

Page 55: two cross-section diagrams marked “E”

The page presents two superimposed pencil sketches. The upper diagram shows an elongated part hatched in cross-section, crossed by three parallel lines, with the letter “E” noted twice. Curves start from the base towards a sinuous line forming a large loop, and circular scribbles are superimposed in the centre p. 55.

The lower diagram follows a similar principle: a part hatched in cross-section, three horizontal lines, a letter “E” in the centre. Two vertical elements evoking tulips or valves frame the diagram, each surmounting a screw or threaded rod, one being designated by a handwritten arrow p. 55.

A small isolated diagram at the top right shows an elongated rectangular shape segmented by vertical lines. A handwritten number, read with uncertainty as “08”, appears at the top left of the page p. 55.

Page 56: almost blank sheet

This page contains no legible text. One can only distinguish, at the top right, a sequence of numbers diagonally whose reading remains uncertain (“15/19” proposed), as well as traces of an impression by transparency whose origin is not identifiable p. 56.

Page 57: conical shape and annex sketches

The main sketch represents a conical or pyramidal shape seen in elevation, of which several curved lines converge towards a rounded hatched summit, dome-like, all organised around a vertical axis of symmetry p. 57. Around this central shape appear several annex sketches: a circular motif evoking a stylised star, a small U-frame with dimension lines, a reduced triangular shape recalling the main dome, and a tapered shape with two internal parallel lines. The lower part of the page shows intersecting arcs and triangles, suggesting a cross-section or a base under the conical shape p. 57.

The transcribed text of this page is almost entirely illegible; only an uncertain number, “30”, could be proposed p. 57.

Context

At Citroën, the design of the hydropneumatic suspension — an invention associated with Paul Magès — involved numerous hydraulic components: valves, clacks, cylinders and reservoirs, whose cross-sectional shapes (tulips, conical seats) are classic elements of plumbing and hydraulic valves. This general knowledge is, however, not explicitly stated in these sheets, which remain silent on their precise function.

Archivist's view

Without legend or dating, these three sheets probably belong to preparatory work sketches, rather than definitive plans: the scribbles and erasures visible on page 55 are an indication of this p. 55. The repeated “E” mark could designate a part or a variant in a series of studies, but nothing in the document allows this to be confirmed.

The conical shape on page 57, with its axis of symmetry and its variants sketched in the margin, evokes the trial and error typical of the search for a part geometry — perhaps a clack or a nozzle — but this reading remains a hypothesis. The near-absence of legible content on page 56 makes it primarily a connecting sheet between the two sketch sheets.

These sketches could belong to the same working collection as other items around the hydraulic components in the file, such as the oil reservoir sketch: needle, seals and fixing or the air/oil device sketch replacing the oil dipstick, without this link being established with certainty for lack of common identification elements.