This invention is directed to an electrolysis apparatus for the removal of unwanted hair and, in particular, to an electrolysis apparatus having a probe that is retractable into a housing for protecting the probe during non-use.
In the removal of unwanted hair by electrolysis, one type of apparatus includes a fine probe or stylet that is inserted into the pore from which such a hair is growing, the probe being inserted until it makes contact with or is proximate a papilla. Current is passed through the probe so as to electrolyze sodium chloride, thereby producing sodium hydroxide which destroys the papilla to prevent future growth of hair within the pore being treated and which makes it possible to extract the hair from the pore readily. A means of passing the current through a resilient probe and through the skin of the individual being treated is explained in U.S. Pat. No. 3,054,405 (Tapper). An improved electrolysis hair removal apparatus of this type is also explained in detail in co-pending application Ser. No. 964,866, filed Nov. 30, 1978, now U.S. Pat. No. 4,216,775, assigned to the same Assignee as this invention, said application being incorporated herein by reference as if fully presented.
Generally speaking, electrolytic reactions in aqueous solutions require a maximum voltage difference of no more than about 2 volts. However, due to the fact that skin resistance is involved, a somewhat larger voltage difference is required, a voltage of about 9 volts generally being found adequate. This voltage is low enough and the current involved is similarly low enough so that the fingers of the individual carrying out the treatment can be used as part of the electric circuit. For this purpose, it is convenient that the portion of the apparatus to be held by the operator thereof be conductive.
Since the probe must enter a pore in the skin, it must, of necessity, be of small diameter, and therefore fragile. As a result, the probe is subject to bending or breakage, especially when transported or otherwise out of use. Moreover, should the apparatus suffer a fall during use, the probe could readily be damaged. The present invention is concerned with protection of the probe as well as increasing the user's convenience in the use of the apparatus.