Plate no. 12 — Diagrams of the rubber starter and its locking mechanism (8 February 1945)

In this document

This technical plate, numbered plate no. 12 and signed P.Magès, brings together three series of diagrams relating to an engine starting device using elastic accumulation, known as a "rubber starter".

Principle diagram of the rubber starter

A double cross-section diagram presents the cylindrical assembly of the device, equipped with a crank, with circled markers "n" and "P" on the left view, then "C", "V", "S", "M", "RL", "n" and "P" on the right view, which is more detailed p. 6. The latter shows elements in a fan shape arranged in two rows around a central axis, evoking rubber blades or blocks p. 6.

Locking mechanism diagram

Three circular diagrams illustrate the locking mechanism in three successive states: "LOCKED", "UNLOCKED" (with markers "M", "V", "O", "r", "R", "L") and "LOCKING 1st STAGE" p. 6. Each state shows a zigzag spring and solid circles arranged in a circumference p. 6.

Unlocking control diagram

Three linear diagrams detail the "unlocking control in the case of torsion by cable": cable mechanism, spring, and a stylized shape evoking a hand operating the device, with movement arrows p. 6.

Handwritten numbers in pencil ("1", "2", "3" and others that are barely legible) accompany the various diagrams, probably to indicate their order or numbering p. 6.

Context

The "rubber starter" mentioned here is part of the research conducted during the immediate post-war period on mechanical engine starting devices that did not use electricity, at a time when batteries remained expensive, fragile, or unreliable.

The idea of energy storage by elastic torsion (here via rubber elements rather than a classic metal spring) recalls the principles of spring starters used on certain small engines or aircraft of the time.

Paul Magès, then a young engineer, would later develop his most famous invention at Citroën, the hydropneumatic suspension; this 1945 patent testifies to an earlier phase of his inventive activity, focused on mechanical energy accumulation solutions.

Archivist's perspective

This plate no. 12 illustrates the rigour of Magès's graphic work in the creation of his patent files: each mechanical state of the locking is represented separately (locked, unlocked, first stage), which suggests a pedagogical concern for demonstration intended for the patent examiner.

It is likely a direct attachment to the Patent project "Starting device for engines" (rubber starter), no. 178, dated the same day, 8 February 1945.

The presence of alphabetical markers (C, V, S, M, RL, r, R, L, O) suggests that this plate was accompanied by a descriptive notice detailing each part — not present in this archive.

It is probable that this plate precedes, in the logic of the file, Plate no. 13 — Electric and automatic unlocking, which deals with an electric and automatic variant of the same unlocking mechanism, here presented in its mechanical cable-operated form.