Sheet 8: sketches of a camshaft and a brake

In this document

This handwritten sheet, numbered "(8) – 8-1-" (the rest of the number being cut off by the edge of the page), bears two technical pencil sketches p. 45.

The main diagram

It shows a technical cross-section of a mechanism viewed from the side: a hatched housing traversed by a horizontal shaft, flanked by bearings or bushings represented by hatched circles. A central cylindrical element topped by a conical part, marked with a downward-pointing arrow, completes the assembly, as well as a screw or bolt at the top left p. 45.

The secondary diagram

On the right, a second sketch shows an end view: a hatched inner circle crossed by a diagonal cross, connected to a rectangular shape likely representing a shaft seen from the side, with a horizontal arrow p. 45.

Annotations

The diagram on the right is surmounted by the mention "Arbre a came" (Camshaft), and an inscription near the horizontal arrow evokes a "Frein" (Brake), followed by an uncertain word ("en" or "ou") p. 45. At the top of the page is an illegible inscription, transcribed as "M.4Ξ" or similar, the meaning of which remains uncertain. Other annotations, in the left margin, are almost erased and illegible.

No complete date is legible: the sheet number "8-1-" is cut, without it being possible to derive a dating from it.

Context

A camshaft is a classic mechanical component of combustion engines, responsible for controlling the opening of the valves; associated here with a brake, the sketch could relate to studies on the transmission or braking of a vehicle — fields on which Paul Magès, an engineer at Citroën, worked during his career, before dedicating himself mainly to hydropneumatic suspension. This connection remains, however, a reading hypothesis, external to the document itself, which specifies neither the vehicle nor the context of application.

Archivist's perspective

This sheet probably belongs to a larger set of working sketches, in the same vein as other pieces from the same collection bearing comparable serial numbers. The cutting of the number "8-1-[…]" suggests that it was part of a more complete bundle, now partially lost or cut during digitisation.

The style — quick pencil sketches, abbreviated annotations, absence of a detailed legend — evokes an exploratory design phase rather than a document intended to be formally archived. It could thus be contemporary with other similar sheets in the collection, such as the handwritten folder "1933" which lists various technical studies, or the workshop forms repurposed as sketch supports, revealing a working method where Magès sketched his ideas on any available medium.

In the absence of a date or complete legend, the main interest of this sheet lies in the testimony it provides on the mechanical design process, rather than in its precise technical content, which is difficult to interpret with certainty.