Patent drawing sheets “Power steering” — figures 1 to 3 (1954)

In this document

Sheet 1 — figure 1 (ref. P 1024-1, p. 8)

This sheet presents a technical pencil sketch of a vehicle steering mechanism. It shows a three-spoke steering wheel connected by a steering column (markers 1 and 2) to a complex mechanical housing p. 8.

The drawing details several components numbered from 3 to 18: a pinion/gear wheel, an articulated link, a rectangular housing (markers 12, 13, 14), as well as a piping system connecting two cylindrical reservoirs marked “R” and “A”, and an element marked “P” connected by conduits p. 8. A dotted line crosses the drawing, probably representing the axis of the steering column p. 8.

The sheet bears the handwritten inscription “fig. 1” and the stamp “P 1024 -1” p. 8.

Sheet 2 — figures 2 and 3 (ref. P 1024-2, p. 9)

This second sheet groups together three technical views.

Fig. 3 shows a cross-sectional view of a symmetrical mechanism with two identical vertical columns connected by a rounded upper part, with springs visible at the base of each column. Numerous markers (36, 37, 38, 30', 30, 21, 22, 19, 33, 26, 29, 23, 34, 35, F, 27, 24, 31, 31', etc.) are annotated there, as well as a curved arrow associated with the letter “F” p. 9.

Fig. 2 represents a mechanism in cross-section with a splined horizontal shaft and a central housing comprising vertical cylindrical parts (markers 17, 18, among others) p. 9.

A third diagram, in the lower part, shows a striated rectangular block connected to an inclined assembly with concentric circles, with markers partially cut off by the edge of the page p. 9. The sheet bears the inscription “P 1024_2” p. 9.

Context

This patent filing dates from 1954, a period when Paul Magès, a self-taught engineer who joined Citroën in August 1925 (autobiographical notes), was developing hydropneumatic suspension mechanisms in the design office — the plans for which date from 17 February 1944 (hydropneumatic suspension plans) — and various power steering systems, then in full expansion in the French automotive industry.

These researches on “power steering” are part of the broader context of innovations preparing the future DS, presented on 6 October 1955, whose hydraulic systems (braking, steering, suspension) would constitute a major technical breakthrough. This link with the DS remains, however, knowledge external to the document: nothing in the sheets themselves mentions it.

Archivist's perspective

These two sheets constitute the technical illustration of the patent file, probably supplementing the textual description of the “power steering” device p. 8-9. The large number of numerical markers suggests a complex mechanism, with several functional sub-assemblies — steering column, control housing, pressurized reservoirs — consistent with Magès' research on servo-hydraulic circuits, conducted during his 49 years spent at Citroën until his retirement in September 1974.

It seems that figure 1 offers an overview of the device, while figures 2 and 3 detail internal cross-sections of sub-components p. 9. These sheets are best read in addition to the French patent application “Power steering for vehicle”, which constitutes the founding text.