Dimensioned detail sketch of pump: threads and diameters (undated sheet)

In this document

This sheet, without header or date, presents two technical sketches accompanied by numerous handwritten dimensions, on a medium bearing a printed graduated ruler p. 4.

The left sketch

It represents an elongated mechanical assembly, with a rounded head topped by a hexagonal nut or bolt, two threaded side rods and an enlarged base. The visual description suggests a component "of the cylinder or shock absorber type with attachment" p. 4, but no precise dimension is legible for this part.

The right sketch

It shows a stepped cylindrical part, seen in cross-section, with a series of annotated diameters and dimensions:

Other values are noted but marked as uncertain by the transcription: φ "2h.7", φ° "22x150 14", d "14 h2", φ "24.5" p. 4. Lateral dimensions complete the diagram: 27.5 / 25 / 15 p. 4, as well as vertical dimensions on the right: 43.5 / 20.5 / 7 / 12 p. 4, and an isolated annotation "63" at the bottom of the page p. 4.

The assembly is described as a "machined mechanical part (axle, rod or valve body) with manufacturing dimensions" p. 4.

Context

This type of dimensioned sketch, undated and without header, corresponds to common practice in post-war mechanical design offices: it is likely a working sketch intended to specify machining dimensions, before or alongside more formal plans.

Paul Magès, a Citroën engineer, notably worked during this period on hydraulic pumps linked to the future hydropneumatic suspension of the DS. This general knowledge is however not attested by the document itself, which bears no mention of Citroën, pump or date.

Archivist's perspective

The vocabulary of the dimensions (diameters φ, threads, dimensions in tenths of a millimetre) and the "working sketch" nature of this sheet suggest that it could belong to the same documentary set as the pump plans dated October-November 1951 kept in the same file, notably the Pump plan QM.399 D / E42.401 T with nomenclature and the handwritten note by Magès on the replacement of the pump drawing.

It seems to be a preparatory sketch or a quick dimensional check rather than an official plan, given the absence of header, title and date, and the handwritten and uncertain nature of several dimensions p. 4. Without internal dating elements, it remains prudent to consider it undated, but its connection with the other pieces in the "self-regulating mono-pump" file would deserve to be verified.