Copyright © Françoise Herrmann
JRB Elissabide filed many improvements for the rope-soled and canvas espadrille. This footwear, considered casual or summer shoes, is one of the Basque region’s flagship products, worn and loved in many places worldwide.
The improvement disclosed in 1948, in FR972184, titled Semelle de corde à épaisseur constante, concerns manufacture and composition of espadrille rope soles.
According to the disclosure of the invention, the prior art of rope soles was such that espadrille soles flattened out very swiftly under the repeated pressure of impact with the ground. That is, an unworn espadrille sole might measure 1 centimeter and flatten down to 4 or 5 millimeters within a few days. The soles lost their thickness because the strands of the rope were braided with a core consisting of textile alfa or jute fibers, which offered no resilience upon repeated impact with the ground.
The invention disclosed in FR927184 thus consists in replacing the core of textile materials within the braid with natural or synthetic rubber strands, or in some variations of the invention, using just the rubber strands.
Following statement of the above identified wear problem, and a brief description of how the proposed invention remediates, the patent further discloses a 4-step manufacturing process The 4-step process claims patenting rights on: (1) the formula of the rubber mixture for the new rubber core, (2) the process of manufacturing the core rubber strands of various diameters out of the rubber mixture produced, (3) the production of the braiding using both the rubber core and outer textile strands, and finally (4) the manufacture of the soles, using the rubber core strands, with or without outer textile braiding.
The resulting product of the invention is then purported to be an espadrille with an unprecedented soft or cushy sole, whose wear or thickness remains constant across time --at least well until the rest of the espadrille falls apart.
This patent does not include any drawings of the manufacturing processes.