Magès patent addendum: anti-roll device for hydraulic steering servo-control

In this document

This sheet is a patent addendum dedicated to an "ANTI-ROLL DEVICE FOR MOTOR VEHICLES" p. 10. The text immediately specifies its purpose: to replace "the pump 28 and the system of valves and pistons described in the 1st addendum", for all cases of use of a hydraulic or pneumatic steering servo-control system for a vehicle, regardless of the cylinder design p. 10.

Principle described

A system of valves 42, mounted on the pipes 43 and 43 bis supplying the steering cylinder 44, creates a pressure difference (P1/P2) in the pipes 45 and 46 depending on the direction of fluid flow. This difference, regulated by the load of the valve springs 47 and 48, moves two pistons 49 and 50, which in turn drive a piston 51 p. 10.

This piston 51 delivers, via pipes 52 and 53, the volume of fluid necessary for the displacement of the piston 19 of the distributor 13 p. 10.

Return to neutral position

The text details what happens if the steering wheel is immobilized during a turn: the pressures balance out via the nozzle 54, and the piston 51 returns to the middle position thanks to the springs 55 and 56 p. 10. Two variants are mentioned: in Fig. 1, the balance is obtained with equal load of the springs 55/56; in Fig. 2, it is obtained by the stop of the spring cups 57 and 58 on the faces F1 and F2 — the trigger pressure can then be adjusted via the spring load p. 10.

The page bears a handwritten annotation "1961" at the top right, a signature reading approximately "M. Magès" or "HH Magès", and a barely legible numerical inscription evoking a "Patent" or "Extract" — these elements remain uncertain and are not used as documentary facts.

Context

As a general historical reference: at that time, Citroën developed the DS, equipped with an hydropneumatic suspension designed by Paul Magès and power-assisted hydraulic steering. The anti-roll devices and steering servo-control systems described here belong to this technical family, although the document itself does not mention the DS or any specific model.

Archivist's perspective

This sheet illustrates the continuous improvement work carried out by Magès: it is an addendum simplifying a previous device ("the 1st addendum"), a sign of an iterative search for reliability and mechanical simplicity p. 10.

It seems that this text is more akin to the legal writing of a patent — precise and numbered — than a standard working note, which makes it a piece likely intended for an official filing. The handwritten "1961" dating is consistent with other items in the collection from the same period, notably the patent application for the three-way valve and the handwritten note on the hydropneumatic shock absorber, which testify to the same effort to develop Citroën hydraulic systems that year.