Proposal for modifying the gearbox fork control (3 March 1935)

In this document

Page 20 — Direct gear control project

The plate presents a "Direct control project" for gears p. 20, with a dimensioned section/elevation view ("70", "approx. 70", "approx. 140") and three supplementary drawings: a "Section c-d" at 1/4 scale showing the angular positions of the selector (PD, 1st, 2nd, R, "forward"/"backward"), a "Section a-b" representing the articulated lever with its pivots, and a "Plan view" at 1/5 scale showing two splined rods connected to a housing, leading to the "Dashboard" p. 20. The document is dated and signed "3 March 1935", a signature attributed to Magès p. 20.

Page 21 — Proposal for modifying the fork control

This is a "Proposal for modification" of the gearbox fork control, the motive for which is explicitly twofold: "Reduction of Cost Price" and "Quality Improvement" p. 21.

The diagram compares the "current position of the levers" (welded lever, tube bored at the ends for graphite bushing, drawn steel, crimping, ball, flywheel housing, spherical bearings tightened in their housing) to a new arrangement where "the position of the levers being able to be raised to the maximum, the engagement of these levers will be done in a more correct way, hence reduction of the operating effort" p. 21.

The text also announces material savings: "3 studs - 2 screws - 3 nuts & washers, 1 key", a time saving in assembly, a saving of one "Tecalémit grease nipple" and a material saving p. 21.

Quantified table of time savings

The total indicated is "21'30 - 3'20 [uncertain]", with a "Machining gain" of "18'10" and a final "Total gain" of "5'70" p. 21, including a foundry saving and a deduction for the price of the graphite bushing.

Context

These plates date from 1935, about twenty years before the appearance of the hydropneumatic suspension that would make Magès famous at Citroën, where he joined in August 1925 at 17 and a half and would spend his entire career, for 49 years, as a self-taught man who became a technical writer and then deputy head of the Super-Control (autobiographical notes). At that time, the engineer was working on more classic automotive mechanical issues: transmission, gearbox, manufacturing cost reduction — typical subjects of machining-assembly methods in the French automotive industry of the interwar period, a few years before his entry into the design office and his first hydropneumatic suspension plans in 1944.

The concern for "reduction of cost price" expressed here reflects the industrial concerns of rationalisation typical of this period, where manufacturers sought to standardise and simplify mechanical components to reduce mass production costs.

Archivist's perspective

This document illustrates, as early as 1935, the working method that seems to characterise Magès throughout his career: a very fine and quantified analysis of each machining operation, pushed to the tenth of a minute, in the service of a concrete technical improvement p. 21.

It is likely a preparatory study from the methods department, intended to convince management with arguments that are both qualitative (reduction of operating effort, p. 21) and strictly economic (the time savings table, p. 21).

This piece can be compared to other studies from the same period kept in the same file, such as the manuscript folder "1933" listing the studies in progress, which testifies to the range of subjects then handled by Magès (gears, injection, carburettor, synchroniser) long before his work on suspension.