Assembly diagram of gearbox control pistons — plan E806-2.200 (Védie, 6 Nov. 1956)

In this document

This technical plan, referenced E806-2.200, presents the « SCHÉMA de MONTAGE des PISTONS de COMMANDE de VITESSE sur B.V. Solution cylindres en 2 parties » (page 23).

The cross-section diagram

The drawing shows two symmetrical (mirror) cross-sectional views of a gearbox control cylinder-piston assembly. Each half-cylinder exists in two diameters: φ=13.5 (E806-2190b and E806-2191b) and φ=11 (E806-2190a and E806-2191a), assembled with DS 334-180 and DS 334-181 seals p. 23.

Parts list

The handwritten markings designate in particular:

• the E806-2199 pushers, to be cut to length;
• the E806-2.198a (φ=11) and E806-2.198b (φ=13.5) pistons;
• the E806-2.196 screw (DS 334-69);
• the E806-2.194 FRONT (DS 334-128) and E806-2.195 REAR (DS 334-127) flanges;
• "fork axes" and a "gearbox cover" p. 23.

Dimensioning

A central dimension indicates « RÉGLAGE BOÎTE 4mm » (GEARBOX ADJUSTMENT 4mm), associated with an arrow « actual piston length », suggesting a clearance or functional adjustment to be respected during assembly p. 23.

Administrative stamp

The plan bears the mention « VALABLE POUR ESSAI 42.806 » (VALID FOR TEST 42.806), signed VÉDIE and dated 6.11.56 p. 23. The Citroën stamp specifies « Solution cylindres en 2 parties » (2-part cylinder solution) as the assembly designation.

Context

This type of gearbox control via hydraulic pistons evokes, in a general way, the semi-automatic control systems developed by Citroën at the end of the 1950s, in connection with Paul Magès' hydropneumatic research. The "E806" numbering and the reference to "DS" seals place this plan within the technical ecosystem of the DS, without the document itself naming this vehicle.

Archivist's perspective

This plan dated 6 November 1956 p. 23 documents a development stage of an experimental gear control assembly, the mention "valable pour essai 42.806" indicating that it is likely a set of parts intended for a specific bench test rather than a final production part.

The "2-part cylinder" solution seems to be a study variant among other hydraulic control approaches tested at that time by the Magès/Védie teams.

This document can be compared to other items in the same file dealing with control cylinders and pistons, such as the BEA inspection of the D 314-02 clutch release cylinder, dated a few weeks earlier (3 October 1956), or the handwritten divider « 54 à 57 — Piston, cylindre de débrayage » which could group these successive tests.