Patent diagram 1000/56 — constant-level suspension mechanism

In this document

This page contains no written text: it is a technical plate drawn in purple ink on brown kraft or tracing paper, framed by a double line.

The diagram

The drawing represents a complex mechanical mechanism organised into three zones:

• At the top: two circles linked together (markers 7 and 8), connected by pipes to a rectangular hatched block with vertical grooves (marker 10), which evokes a radiator or an exchanger.
• In the centre: a set of hatched parts (markers 5, 6, 9) connected by piping, with a connecting rod (marker 4) linking a crank pin to a large graduated disc (marker 1), provided with graduations on its perimeter (markers 2 and 3, concentric dashed lines).
• At the bottom: on the left, a small mechanism with springs and rods (markers 17 to 21) connected to a small wheel and to an assembly comprising a spring and a rectangular block (marker 12); on the right, a small rectangle with an arrow (marker 11).

Twenty-one numerical markers (1 to 12, then 17 to 21) identify the various parts of the mechanism, with no associated legend on this page.

Inscription

Outside the frame, at the top left, a handwritten annotation in pencil indicates "[uncertain: "1000/56"]" — this reference remains uncertain upon reading.

Context

This type of plate is part of the usual practice for patent files of the time: a numbered technical diagram generally accompanies a descriptive text where each marker is explained piece by piece.

The presence of a graduated disc, a connecting rod and springs, associated with the mention of a "1000/56" potentially evoking a file number from the year 1956, likely links it to the world of suspension patents filed by Citroën during this decade. This period corresponds precisely to Paul Magès' work on hydropneumatic suspension, whose initial plans date from 17 February 1944 (Hydropneumatic suspension plans with differential interaction (17 February 1944)), the first tests on 2 CV from May to July 1946 (Notebook of the first 2 CV hydropneumatic suspension tests (May-July 1946)), and whose most visible culmination is the DS presented on 6 October 1955 — the present plate being a continuation of this research.

Archivist's perspective

Without a legend or accompanying text on this page, it is impossible to state with certainty the exact function of the mechanism represented: the original description mentions a "constant-level" device, but nothing in the diagram itself p. 12 allows this to be confirmed unequivocally — only the numerical markers and the general layout of the parts (connecting rod, graduated disc, springs, exchanger) are attested.

It seems probable that this plate is an annex document intended to illustrate a patent text now separated, perhaps related to the 1956 Patent "Improvement to vehicle suspension", which deals precisely with constant level and servo-control. A comparison between the two documents would make it possible to verify if the numerical markers correspond.

In any case, this fragment illustrates the care taken by Paul Magès in the graphic representation of his inventions, including in technical parts most devoid of text.