Wales « Hydra News » No. 1 (1953): tension spring with dampened return

In this document

This is issue number 1 of the Hydra News bulletin, published by the Wales-Strippit Corporation (Hydra Spring Division, North Tonawanda, N.Y.), dated © 1953 p. 17.

The product presented

The bulletin highlights the 687 series, a « tension spring with dampened return », exploiting the compressibility of liquids — the principle of Hydra Springs p. 17.

A photograph shows a rectangular metal housing dimensioned « 6 1/4″ » high, « 2″ » and « 5″ » for the other dimensions, equipped with an « adjustable valve for dampened return » p. 17.

Characteristic curves

A « CHARACTERISTICS » graph (force in pounds from 1000 to 6500, stroke from 0 to 2.86 inches) presents two curves:

• one for « extension » in 1/40 of a second,
• one for « dampened return » in over 1/3 of a second p. 17.

Sales pitch

The text indicates that this unit replaced « unsatisfactory hydraulic cylinders, piping, valves and remote hydra-pneumatic accumulator » in a military installation, and that it was manufactured in a rectangular shape to adapt to the available space p. 17.

A comparison is given: an equivalent coil spring, made of 1-inch diameter wire, would measure 17″ long by 5 3/8″ in diameter p. 17.

A document fragment superimposed at the top of the page remains largely illegible (« ...BS — MAX FOR... », « (Below) »), with no usable information.

Context

Wales Hydra Springs exploited the low compressibility of liquids to store mechanical energy, a technical path close to — though not identical to — the hydropneumatic suspension developed by Paul Magès at Citroën, which combines liquid and gas.

The early 1950s correspond, in Citroën's history, to the development period of the future DS, presented in 1955, for which the hydropneumatic suspension constitutes the major innovation.

Archivist's perspective

This document belongs to a series of Hydra News bulletins kept in the Magès archives; it seems that the engineer closely followed competing or parallel « liquid spring » solutions, as evidenced by other items in the same file, such as Hydra News No. 2 or Hydra News No. 3.

This number 1, dedicated to a dampened tension spring for military use, likely illustrates Magès' technical and documentary monitoring of alternatives to his own hydropneumatic suspension, a monitoring that would continue until the early 1960s, as shown by his later comparative notes on gas springs and liquid springs.

The low density of quantified technical information (excluding the graph and dimensions) limits the analysis to an essentially promotional document.