Specification of John Henry Johnson : artificial palates.

  • Johnson, John Henry
Date:
1875
Catalogue details

Licence: Public Domain Mark

Credit: Specification of John Henry Johnson : artificial palates. Source: Wellcome Collection.

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    6 _Johnson?8 Improvements in Artificial Palates. either a liquid or solid nature, the valve is arranged in such a manner as to open upwards and to close again immediately when the food has passed beneath it. As also the back portion of the pharynx is narrower in its upper part, corresponding with the cavity of the nose, the valve is so 5 arranged as to become shortened or contract slightly at the moment when it opens, that is to say, at the same time that it is raised it is displaced, moving forwards into the cavity of the palate. It is evident therefore that with this arrangement the valve operates in exactly the same manner as the velum or curtain of the palate in its natural condition. 10 This displacement of the valve is obtained by very simple mechanism which is arranged in the following mannerThe upper surface of the palate plate is provided with a hinge of gold or platinum to which is jointed by means of a screw a flat lever of gold, which extends to the interior of a species of sheath or slide composed of the same metal, and 15 fitted in the valve constituting the rear part of the apparatus. This sheath d its 1 a screw which is capable of traversing or sliding along a longitudinal slot formed in the lever, by which means the parts are connected together whilst the valve is free to move as before-mentioned, the position of this screw and the dimensions of the 20 slot limit the extent of the recoil motion of the valve in such a manner that it corresponds only with the regular working of the system. A spiral spring of gold fastened by two screws, one of which is fitted upon the hinges above mentioned, and the other upon the valve, is employed for the purpose of causing the latter to resume its normal 25 position which it is to occupy, and from which it is removed in con¬ sequence of the displacement produced by the act of deglutition. And in order that the said Invention may be fully understood I shall now proceed more particularly to describe the same, and for that purpose shall refer to the several Figures on the annexed Sheet of Drawings, 30 the same letters of reference indicating corresponding parts in all the Figures. Figure 1 of the accompanying Drawings is a plan; Figure 2 is a sectional elevation, and Figure 3 are detail views of apparatus con¬ structed according to one mode of carrying out this Invention. 35 Figures 4, 5, and 6, are similar views illustrating a modification of the
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