Direct gear control project for the PV 11 cv (1935)

In this document

This handwritten plate is produced by the Direction des Fabrications Mécaniques (Mechanical Manufacturing Directorate), Méthodes Usinage Montage (Machining and Assembly Methods) department, and bears the title "Commande des Vitesses — Projet de commande directe" (Gear control — Direct control project) p. 1.

Diagrams and sections

The document presents several technical views articulated with one another:

• A general view at the top left of the gear lever mechanism, with two section points marked a and b p. 1;
• A central diagram titled Commande des vitesses (Gear control), with horizontal rods dimensioned "70" and "70 approx.", between markers c and d p. 1;
• A "Projet de commande directe" (Direct control project) diagram dimensioned "140 approx." p. 1;
• A Section c-d at 1/1 scale, showing three rods in section, a "Fixed" element, and the positions 2e (2nd), M.AR (reverse), 1a (1st) and PD, with "backward" / "forward" arrows p. 1;
• A Section a-b, a sectional view of a lever articulated on several axes of rotation, with alternative angular positions in dotted lines p. 1;
• A Plan view at 1/5 scale, showing two rods connected to ball joints annotated PD, 2e, 1er, M.AR, leading to an assembly of rods up to the dashboard p. 1.

The document is dated and signed: "Le 3 mars 1935 Magès" (3 March 1935 Magès) p. 1, which corresponds exactly to the already known dating of the piece.

Context

At that time, Citroën was manufacturing the PV 11 cv (Traction Avant), and Paul Magès, who joined Citroën in August 1925 at 17 and a half (autobiographical notes), was working in 1935 as an engineer in manufacturing methods, several years before his first work on hydropneumatic suspension (braking limiter for the TUB van, then joining the design office in 1939-1940).

A "direct gear control" refers, in the automotive vocabulary of the time, to a linkage system connecting the gear lever to the gearbox, without using cables or intermediate relays — a simpler and more rigid solution than other assemblies then being tested on the Traction Avant models.

Archivist's perspective

This plate bears witness to very concrete engineering work, precisely dated, at a time when Magès still held positions related to manufacturing methods rather than the breakthrough innovation that would later make him famous — this would only begin to take shape at the end of the decade, with the braking limiter for the TUB van and then the first hydropneumatic suspension plans of 17 February 1944 (hydropneumatic suspension plans).

The same day, another piece in the file proposes a Proposal for modifying the gearbox fork control — it seems that these two documents belong to the same project for refining the transmission of the PV 11 cv, the gear control itself p. 1 and that of the internal gearbox forks constituting two complementary aspects of the same mechanical problem.

The interest of this archive lies above all in the precision of its technical drawing (1/1 scale sections and 1/5 scale plan view), revealing the methodical rigour already at work in Magès before his major inventions.