Calculation sheet and sketch on Citroën form (spring, Ø 20 mm)

In this document

This sheet is a blank form from the Société Anonyme André Citroën, bearing the usual printed boxes: "Nbre de Pages" (Number of Pages), "PAGE N°" (PAGE No.), a "VALABLE POUR" (VALID FOR) table with NAME / DATE / VISA columns, as well as the fields "LANCÉ PAR NOTE N°" (LAUNCHED BY NOTE No.), "REMPLACE" (REPLACES), "ARRÊTÉ A LA MODIFICATION" (STOPPED AT MODIFICATION) p. 60. The mention "REPRODUCTION INTERDITE" (REPRODUCTION PROHIBITED) appears under the Citroën header p. 60.

In the centre of the page is a hand-drawn pencil sketch representing a cross-section of a cylindrical mechanical part, with a vertical rod, hatching, and a series of small circles that could evoke balls or rollers p. 60.

Three handwritten annotations accompany this sketch:

• "3,5 à 4", with an arrow pointing towards the top of the diagram p. 60;
• "Φ 20 mm", underlined twice, with an arrow pointing to the left p. 60;
• "5 Kg", underlined, positioned below the previous one p. 60.

No date, author's name, or explicit legend for the sketch appears on the page. The technical reference "MM 4.59 5000 TA 4 1" appears at the bottom of the page, probably a print run number for the form p. 60.

Context

"Société Anonyme André Citroën" forms of this type were used by the manufacturer to record calculations, sketches, and technical notes within a standardised framework, before their potential formalisation into a drawing or memorandum — a common practice in post-war industrial design offices.

The 20 mm diameter and 5 kg load mentioned here could refer, within the broader scope of Paul Magès' research on hydropneumatic suspension, to small-sized elements such as springs, balls, or regulation parts — although the document does not allow this to be stated with certainty.

Archivist's perspective

This sheet, lacking a date and explanatory text, likely pertains to a calculation or a quick preparatory test, recorded in pencil on a Citroën administrative medium. The sketch and the numerical annotations (Φ 20 mm, 5 kg, "3.5 to 4" wire) suggest component dimensioning — perhaps a spring or a ball-bearing element — but their precise use remains unspecified p. 60.

The vocabulary of balls mentioned in the description of the sketch recalls, by analogy of material, other documents in the same collection relating to hydraulic components, such as the memorandum by Paul Magès on defective balls in DS HP pumps, without a direct documentary link being established here.

This document clearly illustrates the fragmentary and often undated nature of many calculation sheets kept in the Magès archives, which need to be recontextualised using neighbouring documents in the same folder, such as the summary of the "Hydraulic components" folder.