US1419839A - Process of manufacture of zinc cups intended for dry cells - Google Patents

Description

' To all whom it may conica /"n.

I UNITED STATES PATENT OFFICE.

ESPRIT LEON GASTON, OF LYON, FRANCE PROCESS OF MANUFACTURE OF ZINC CUPS INTENDED FOR DRY CELLS.

No Drawing.

Be it known that l, ltsrnl'r LlioN (lrAs'roN, a citizen of the Republic of France, residing at Lyon, France, have invented new and useful Improvements in Processes of Manufacture of Zinc Cups Intended for Dry Cells, of which the following is a specification.

The present invention relates to a process for the manufacture of zinc cups intended for use With dry cells, the said process being radically different from those used up to the present.

According to the method of manufacture employed up to the present, these cups are made by taking sheetminc, giving it a cylindrical form and subsequently fixing thereto a bottom, also of zinc. The different phases of this manufacture constitute many manual operations, which require a certain amount of skill on the part of the workman, not to mention the question of labour, the cost price of which increases daily. On the other hand, the raw material may not in all cases consist of pure zinc. ()n the contrary, it may be affirmed without fear of contradiction that when using sheet-zinc, the zinc is never pure and it is precisely for this reason that the cells do not last longer. The impurities contained in sheet' zinc form, under the action of the products constituting the charge of the cell, local circuits which attack the cups at certain points and corrode them, thus putting the cell out of action.

On the other hand, soldering and acid have a prejudicial effect on the cell. It is true' that efforts have been made to obviate these drawbacks by amalgamating the zinc, but it is impossible to effect this, firstly on account of the soldering and secondly in view of the lack of thickness of the zinc.

It is therefore extremely desirable that, first of all, the zinc shall be as pure as possible.

The present invention relates to a method of manufacture which permits of producing cups of absolutely pure zinc. Moreover, this process, so to speak, does away with all labour, the operation being effected without the manual co-operation of any workman.

In principle, the invention is characterized by the application of electro-plating to the manufacture of the said zinc cups, whereby it is possible to ensure that the metal is of the highest degree of purity and to reduce manual work to a minimum, while moreover,

I Specification of Letters Patent. Patented June 13,1922. Application filed June28, 1920. Serial No. 392,458.

this nanual work can be effected by unskilled labour.

The invention is further characterized by a special arrangement of support upon which the metal is deposited owing to the action of the electric current, said arrangement being devised to prevent the metal from adhering too strongly to this support, thereby rendering it possible to detach it easily and rapidly without risk of damaging the finished cup.

The manufacture of these cups is effected by the means commonly employed in electroplating. A suitable support corresponding to the shape and dimensions of the cup which it is desired to manufacture is placed within the electrolytic bath and the zinc is allowed to deposit itself thereon until the desired thickness is obtained, the support is then withdrawn and the cup is detached by any suitable means which need not be further described. In order to facilitate removal of the cup from its support, this latter could be made with a slight taper.

The support, which is of any suitable material, may however be made of aluminum. preferably alloyed with graphite, copper or other conducting material. The inventor has found that if the support is made of the materials'usually employed, the deposited metal adheres strongly to the support so that it is difficult to detach it therefrom, if not impossible to do this without damaging the cup.

Now aluminium, which has not hitherto I been used as support, constitutes a very advantageous materialin that the deposited Zinc does not adhere thereto as strongly as it does to hitherto-used materials .and it is therefore more easily detached therefrom. The support may be of solid aluminium or in the form of a sheath connected to a core of any suitable material. The inventor supports in an electrolytic bath will merely have to do'this and to'detach the cups'from their supports once the electrolytic deposit has been effected.- In other words the operation proper will be effected automatically without any labour being required, thereby effecting a considerable saving over the usual manual processes. not to mention the great advantage that the cup, being of chemically pure zinc, gives the cell a considerably longer life. The electrolytic bath is composed almost entirely of sulphate of zinc to which is added a small quantity of chloride of ammonium. The preferred strength of the current employed varies between 5 and 6 amperes per square decimeter. As to the support in practice this is composed of aluminum exclusively as it is found in the trade or commercial aluminum.

1 claim:

1. The herein described process for the manufacture of zinc cups for use in dry cells, which consists in immersing analuminum support in an electrolytic bath, causing the deposition by electrolysis from the bath of substantially chemically pure zinc upon the aluminum support in a one piece electric dry cell cup structure, removing the aluminum supportwith the one piece cup formed thereon from the bath, andsubsequently stripping the cup from the alumi num support, substantially described.

2. A process for the production of metallic cylinders closed at one end by an integral portion, Which consists in electric depositing upon the lateral face and one end of a mandrel a thin coating of metal. forming the wall of the cylinder and one end thereof integral with said wall, and then Withdrawing the cylinder and end portion longitudinally from said mandrel.

ESPRIT LEON GASTON.-