Body plan D314-11 — Clutch control cylinder (specifications, 1955)

In this document

This sheet is the specification plan for part D314-11, designated "CLUTCH CONTROL CYLINDER" in the official title block.

Tolerances and specifications

The "SPECIFICATIONS" table at the top of the page sets several geometric checks in relation to diameter Ø1(30):

Radii not dimensioned are set at 5 p. 12.

Detailed dimensions

The page presents a perspective view of the part with numerous diameter, radius and angle dimensions, as well as a "TYPE DETAIL" showing a 35° chamfer and a dimension of 0.7 p. 12. Two cross-sectional views (Section A, Section B) and a Section C specify internal dimensions, notably Ø1 = 18.5 +0.02/0, Ø3 = 23.1 ±0.05 and Ø4 = 19.5 ±0.06 p. 12.

Material and title block

The title block indicates manufacturing in "CA CAST IRON", without treatment or coating, for a weight between 250 and 271/272 p. 12. The plan reference is D314-11, replacing the assembly D314-02 p. 12.

Approvals

The table of contributors mentions, all dated 1 July 1955: Guyétant (Indus.), Belloncle (Verif.), Cadiou (B.E.A.); the drawing is signed by Beaujoin, dated 28 June 1955 p. 12. A handwritten modification line at the bottom of the page bears the mentions "retait 23280", "30-2t-54" and the reference "E874471" p. 12.

Context

The clutch control cylinder belongs to the hydraulic circuit of the DS, for which Citroën generalized the use of hydraulic pressure for multiple functions (suspension, brakes, steering, and semi-automatic clutch). This type of component falls under the daily work of the Citroën Automotive Design Office (B.E.A.) in the mid-1950s, a period of intensive development before the launch of the DS in 1955.

Archivist's perspective

This plan, dated 1 July 1955, illustrates the degree of precision required for a component that is secondary in appearance but essential for the proper functioning of the assisted clutch: the tolerances to the hundredth of a millimeter p. 12 testify to strict industrial requirements, probably linked to the reliability sought for the new generation of Citroën vehicles.

It seems that this part D314-11 is part of the same family of components documented elsewhere in the collection, notably Plan D314-02: clutch control cylinder and piston and the Dimensioned plan of the clutch control piston D 314-12, which seem to constitute the same mechanical assembly studied in parallel by the B.E.A.