Plan and note on the synchronism indicator (electrical "top" mechanism)

In this document

Page 6 presents technical pencil diagrams spread over two sheets, accompanied by a short handwritten note in ink.

The handwritten note

The text, underlined as a title, is explicit: "Indicateur de synchronisme" (Synchronism indicator), followed by the description of its operation: an "'Top' électrique au moment où les 2 mouvements sont à la même vitesse" (Electrical "top" at the moment when the 2 movements are at the same speed) p. 6. It is therefore a device intended to signal electrically the precise instant when two mechanical movements reach an identical speed.

A handwritten numbering "43 44" appears at the top of the right-hand page p. 6, although it is impossible to say with certainty whether it is a date, a plan reference, or a part number — the exact meaning is not specified in the document.

The diagrams

On the left-hand page, several pencil views detail a mechanism: a vertical cross-section evoking a cylinder or a worm gear device with a cam and bearing, a front view with a U-shaped support, and a cross-section of a threaded cylindrical part carrying a gear wheel p. 6. Handwritten annotations run along the dimension lines, but they are too illegible to be used.

The right-hand page shows a similar mechanism — screw, spring, housing — with an enlarged detail of a screw, nut, and washer, as well as a circular view connected by construction lines to the main diagram p. 6.

Context

A "synchronism indicator" of this type evokes, in the technical vocabulary of the time, an electrical sensor or contact triggered by the equality of speed between two mechanical components — a common need in transmission, clutch, or regulation studies. This general context is, however, not detailed in the document itself, which remains focused on the principle and the mechanical sketch.

The date of 1943 suggested for this archive is consistent with the period when Paul Magès, then at Citroën, was conducting numerous parallel technical studies, as evidenced by other items in the same file dated late 1943 and 1944.

Archivist's perspective

This document appears to be a principle sketch rather than a finished plan: the pencil views, the partially illegible annotations, and the absence of complete dimensions suggest an early stage of reflection p. 6.

The subject — electrically detecting an equality of speed between two movements — could be linked to the broader concerns of mechanical synchronization found in Magès's work on servocontrols and automation, without a direct link to the hydropneumatic suspension being established here.

The number "43 44" could indicate a chronological proximity to other items in the file, such as the Note from Paul Magès to Mr. Cadiou: "I need a draftsman", dated 10 December 1943, or the List of problems under study as of 22 February 1944, which provides an overview of the subjects handled by Magès during this period.