Wales “Hydra Springs” Bulletin (1952): hydraulic cylinders and Comproil fluids

In this document

This booklet is the 3rd edition of the “Hydra Spring Bulletin” from the American company Wales-Strippit Corporation, based in North Tonawanda (New York State), dated by its price list of 1 October 1952 and bearing the mention COPYRIGHT 1952 p. 12-14.

Principle and characteristics

Wales Hydra Springs exploit the compressibility of special fluids, Wales Comproils, to reproduce the action of a classic mechanical spring. The document claims they develop “up to 600% more force than conventional springs of equivalent size” p. 13. On models 52300 and 53050, a simple turn of a “force adjuster” (vernier) allows the force to be varied without changing parts (p. 13, p. 15-16).

Models presented

Three models are detailed with their cross-sectional drawings and force/stroke curves:

Comproil fluids are sold separately: Comproil 100 (10% compression at maximum load) and Comproil 62 (6.2%) (p. 14, p. 16).

Cited applications

The document mentions uses in metal cutting tooling, punching presses, machine tools, plastic injection molds (with a concrete example: the addition of four extra cavities in a mold), as well as “special” applications such as thread rolling roller support, a cable tensioning device, and “various military applications of an unusual nature” (p. 13, p. 16).

The company president is named: George F. Wales, Chairman p. 16.

Context

Wales-Strippit was, in the 1950s, an American manufacturer of press tooling and industrial hydraulic components. This type of “liquid spring” based on compressible oil differs from classic metal springs by its compactness and adjustability — a technical principle close, in spirit, to what Paul Magès would develop for the hydropneumatic suspension of the future Citroën DS.

At that time, Magès was working at Citroën on fluid suspension systems, and foreign technical documentation (American, British) served as a source of monitoring to compare existing solutions.

Archivist's perspective

This 1952 commercial bulletin likely falls under the technological monitoring conducted by Magès on the principles of “liquid springs,” a line of research he would deepen himself in his comparative notes of the 1960s.

The repeated presence of the Wales-Strippit collection — several issues of Hydra News are also preserved — suggests diligent tracking of this company by Magès or his entourage. This document can be linked to the Thaon-Cadiou memo on “Hydra-Springs” springs, which attests that these products were indeed circulating in internal Citroën exchanges, as well as Magès' drafts comparing gas springs and liquid springs, where the question of fluid compressibility — at the heart of this bulletin — is directly taken up from an automotive design perspective.