US2541931A - Leakproof dry cell - Google Patents

Description

Feb. 13, 1951 D. McAcHRoN ETAL LEAKPROOF DRY CELL Filed July 9, 1947 www Patented Feb. 13,1951- dgar D. McEachron, "George Il. Schroeder, and Henry G.

Edgar J. McEachron,

Wausau, Wis., assignors to Marathon ,Battery Company, Wausau, Wis., u. corporation of Wiscousin Application July 9, 1947, Serial No. 759,890

This invention relates to improvements in'elecytrlcal dry cells and more particularly to an improved constructiontherefor which prevents the exudation or leakage of any part of the contents of such a cell and therefore eliminates possible damage to associated equipment.

v.'Io prevent such leakage in dry cells of the type which have been widely used in flashlights has becomeA increasingly important, since such cells are also now being used-in equipment of considerably greater value, such as hearing aids or portable radio receivers. f

Numerous types of construction have been del veloped with the idea in mind of eliminating the danger of .cell leakage. In most of these types of construction yit has been necessary to sacrifice Y some of the other desirable characteristics of the cell in order to obtain a non-leaking variety. For

instance, in the ty'pe of construction utilizing the double 'zinc cup, the size of the inner can and the bobbin of depolarizing material and the volume of electrolyte have necessarily been reduced. This is true, since the outside dimensions. of flashlight cells have been standardized by the industry for obvious reasons. Therefore any inof an all metal double-wall construction without 'A the expense of a metal jacket or second cup.

It is therefore the object of this invention to provide a practical, inexpensive and elllcient cell having a protective casing which entirelyeliminates the danger of leakage from the cell and which consequently eliminates the disadvantages which result from such leakage. Y j

It is a further object to provide a cell ofthe character described without sacricing other desrable characteristics such as reducing the volume of active ingredients contained therein.

Y An additional object is to provide an electrical dry cell which is of leak-proof construction but which may be manufactured at a cost comparable with cells of the non-leak-proof variety.

Further objects and advantages of this invenn tion will become evident as the description proceeds, and from an examination ofthe accom- 5 claims. (o1. 13s-133) panying drawingjwhlch illustrates one embodiment of the invention and in which similar numerals refer to similar parts throughout the several views. v,

In the drawing- Fig. 1 is a vertical sectional view of a dry cell embodying one form of this invention;

Fig. 2 is an exploded view of the various parts making up the dry cell. as shown in Fig. 1, the parts being shown in their appropriate vertical relation to each other;

Fig. 3 is a top plane view of the cell shown Fig. 1.

' Referring now to Figures 1 andz, the dry cell has the zinc cup electrode III which contains the usual bobbin I2 and the electrolyte M. The electrolyte il is disposed between the outer surface of the bobbin I2 and the inner surface of zinc cup I0. A carbon' electrode I6 is centrally disposed in the depolarizing material forming the mam body of the bobbin l2 and projects froml the upper end of the latter. vThe insulating disc .The disc 22 is preferably of vulcanized i'lber and has at least its underside coated with a suitable protective material 26, such as one of several grades of vinylite nishes which are well known in the art which are resistant to the action of the materials within the cell.

A suitable thermoplastic material 30, such 'as the usual asphalt compound, is poured over the disc 22 while in a plastic condition and allowed to solidify to form a `seal above this disc. The cap 32 of'suitable metal may be force-fitted over the carbon electrode I6 prior to the application of this thermoplastic material 30 so that its lower edge extends into the material 30 when the latter has solidified, as shown in Fig. 1.

A thin resilient sheath or film 36 which may be formed of any suitable rubber-like substance which is substantially impervious to the materials which may exude from the dry cell, together with a jacket 38 formed of paper or other suitable in-l expensive material to which the sheath 36 is internally secured, is then placed over the zinc cup. This film 36 and the paper jacket 38 are preferably of a pre-formed construction and make up a laminated cover for the zinc cup. The film I8 is secured to the inner surface of the paper jacket 38 with a suitable cement prior to the time the laminated cover is slipped over the can III. The laminated tube is of the same length as the zinc cup I Il so that the upper and lower edges of the tube are ilush with the upper edge and the base 28 of the cup I0, respectively.

A second disc 34 which has a central opening 35 adapted to enclose the cap member 32 is then fitted over the protruding carbon electrode I6 and seated on the upper edge of the zinc can I0, the sheath 36, and the paper jacket 38.

The anged closure 40, which may be of a construction similar to that disclosed in the McEachron et al. Patent No. 2,332,456, is then placed in abutting relation with the disc 34 so that the peripheral edge of the central opening 42 in the closure is in spaced relation to the circumferential side of the cap 32 on the carbon electrode I6, and the ange 4I extends downwardly adjacent the paper jacket 38. The ilange 4I of the closure 40 is then crimped inwardly so as to engage the peripheral edge of the disc 34, together with the upper edges of the jacket 38, the film 36 and the zinc cup I0. As shown in Fig. 1, the disc 34 serves to insulate the upper edge of the zinc cup I from the main body of the metal closure 48, and the upper vedge of the paper jacket 38 serves to insulate the crimped, peripheral edge of the closure.

40 likewise from the cup I0. This disposition of the metal closure 48 effectively seals the open end of the cell. The film 36 is also effectively sealed against the zinc cup I0 at the point at which the peripheral edge of the closure 40 is crimped inwardly. 'This is true since, as shown in Fig. 1, the inward crimping of the closure 40 also results in a crimping of the upper edge of the zinc can I 6 and the upper edge of the paper jacket 38.

' The upper edge of the film 36 is therefore effec-` tively compressed by the crimped paper jacket againstY the correspondingly crimped portion of the zinc cup.

This inward displacement of the zinc cup I0 occurs immediately-above the disc 22, so that the latter is effectively locked in place by the bead 26 and this displacement. The presence of the thermoplastic 30 together with this locking action insures a tight seal between the zinc cup I0 and the disc 22 around its peripheral edge.

A flanged ring 44 with a, large central opening 46 is then slipped over the bottom Yof the cell with the insulating ring washer 45 therein so that it encloses the bottom edge of the jacket 38 and is ush against the washer 45 which is, in turn, ad-

jacent the base 20 0f the zinc cup I0. The flange on this ring is then crimped tothe bottom of the cell, effectively sealing the film 36 to the zinc cup I0 in substantially the same fashion as described above in connection with the sealing action of the closure member 40. After the ring is so disposed it is electrically insulated from the zinc cup elecrode IU just as is the closure v40. The crimping of the flange on the ring 44 also displaces the jacket 38 and the zinc cup I6 to form the bead 48 immediately above the insulating disc I8.

From the above description it will be seen that the zinc cup Ill is tightly enclosed by the laminated tube made up of the paper jacket 38 and the lm 36. Since it sometimes happens in this type of dry cell that the zinc can is partially consumed and corroded during the normal use of the cell, with the result that'the electrolyte housed within the can is forced or otherwise leaks out of the zinc can to the exterior thereof, some suitable method of confining these exudations is A characteristic of such cells.- In case perforation of the zinc cup occurs, the material forced through to the external surface of the cup will be dispersed over the entire outside surface of the cup between the latter and the film 36, since such material is of a fluid or semi-fluid nature. The pressure seals between the lm 36 and the zinc cup I 0 described above will maintain such exuded material in the larea between these circumferential seals, and the lm 36, being impervious, will prevent it from passing through to the paper jacket.v y

Due to the generation of gases within the cell during the period of use, considerable pressure is often built up in the interior of the cell. This pressure often forces the electrolyte out through any perforations which may have been formed in the zinc can. It is therefore important that any material which is utilized to confine this exuded material has sufficientl strength to withstand such pressure as it is built up without becoming distorted. This material should be such that it permits no appreciable'swelling to take place, for instance, since valuable'equipment can be damaged as readily by such swelling as by the corrosive eiects of the exudations. Byfcrimping the paper cover at each end so that it isvtightly compressed against the zin-c can, it is normally held under a slight longitudinal tension. This tension tends to resist any outward displacement of the cover such as thatl which might occur when the electrolyte or other material is forced out lof the zinc cup into the area between the cup and the film.

Although the film 36 does not extend beyond the bottom edge of the zinc can I6 and the base of the can 20 is `therefore expcsed through the central opening 46 in the flanged ring 44, there is no danger of leakage at this point. This is true because the insulating disc I8 is composed of a material which protects the base 20 from the chemical action which ordinarily takes place on the sidewall within the cup. 'I'he base is therefore protected from possible corrosion and resultant leakage. Furthermore, since there is a circumferential seal between the film 36 and the zinc can I0 adjacent to the base of the can, exuded material cannot leak down from the sides of the can into contact with the external surface of the base 20 of the can. This construction of the bottom portion of the dry cell not only eliminates the danger of leakage in this area but also provides a simple method of producing a circuit terminal at the bottom end of the can.

It has been found desirable to pre-form the lm 36 and the paper jacket 38 as a laminated tube prior to dispo-sing either the film or the paper jacket on the zinc cup Il). If the film 36 is handled independently it is much more difflcult to maintain it in the proper shape in order to easily insert the zinc can I0 therein. For instance, a tube of such material has a tendency to remain collapsed in the form of a flat strip with the two sides of such strip adhering firmly to each other. Opening this collapsed tube and maintaining it in such an open form is a problem which causes diiiiculty in a mass production technique. In addition, it has been found that it is impossible under current methods of manufacture to produce a tube of suitable resilient material which has dimensions .accurate enough 1 to make it satisfactory the ytolerances must be qultef'small. Also, the Adimensions .of most materials of this generaltype are radically affected by-changes in temperature,

5 for this typeof use, where so that it' would be necessary tov closely control the room temperature during the manufacturing process. A

Under the preferred procedure the formation of the laminated tube can be carried out by spirally winding a strip of suitable rubber-like material on a mandrel so that its edges overlap. These edges are then sealed by heat or a suitable adhesive to form the illm 36. Thereafter asuitable adhesive is also applied to the outer surface of this resilientmaterial and a strip ofpaper or like material is spirally wound thereover to form the jacket 38. The completed tube is then cut to the proper lengths which are removed from the mandrel and the individual sections so formed may then be slipped over the zinc cup to form the protective covering described above.` 'Ihe flanged metal closure is then spun in retaining engagement with the paper jacket and the side wall of the can at thetop of the cell, and the anged ring is similarly spun in place at the bottom of the cell, all in accordance with the description set out above.

The operations of inserting the cell into the section of laminated covering material and the spinning of the metal closure and the flanged ring into the desired position are such that they lend themselves to being accomplished by high speed mechanical means. This fact plus the elim- Iination of a large portion of the metal usually ly engaging ,said vcore electrode'- and said cui) electrode, a sleeve offlexible, rubbery material substantially impervious to-the possible exudations of said dry cell non-adherently sheathing said cup electrodefa non-metallic `cover secured to and overlying said sleeve, a flanged metal ring closely embracing the lower end of said dry cell, the flange onsaid ring being in crimping engagement with the lower edges of said cover, said sleeve and said cup electrode, a disc of insulating material disposed between the baseof -said core electrode and the inner surface of the baseol. said cup electrode, said crimping engagement 'of said flanged ring being such that said electrode is inwardly displaced immediately above said disc so as to lock the latter against said base of said cup electrode, a flanged metal disc closely embracing the upper end of said dry cell. the flange on said disc being in crimping engagement with the upper .edges of said cover. said sleeve, and said cup electrode, the crimped portions of said anged disc and said flanged ring causing said resilient sleeve to be compressed between said cover and said cup electrode so as to form a tight pressure-seal between said sleeve and said cup electrode adjacent its upper and lower ends, and means for insulating said flanged disc and said flanged ring from said cup electrode.

adherently embracing the outside walls of said4 can. means for closing said can disposed inside thereof, said means closely engaging the`inner side Walls of said can and a flanged metal disc said carbon electrode, tightly embracing the upper end of said dry cell, the flange on said disc being v in' crimped relation with. the outside walls of said tion. Changes in form and in the proportion of A parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention.

What is claimed is: l

l. A non-leaking dry cell provided with circuit terminals at both ends comprising a metal cup electrode, a core electrode, meansfor closing said cell comprising a no-n-conducting material close- Ily engaging said core electrode and said cup electrode, a sleeve of flexible. rubbery material substantially impervious to the possible exudations of said dry cell non-adherently sheathing said cup electrode, a non-metallic cover secured to and overlying said sleeve, a flanged ring closely embracing the lower end of saidy dryv cell, the flange on said ring being in crimping engagement with the lower edges of said cover, said sleeve and said cup electrode, and a flanged disc closely embracing theupper end of said dry cell, the flange on said disc being in crimped relation with l the upper edges of said cover, said sleeve, and

said cup electrode, the crimped portions of said flanged disc and said flanged ring causing said resilient sleeve to be compressed between said cover and said cup electrode so as to form a tight pressure-seal between saidA sleeve and said cup electrode adjacent its upper and lower ends.

2. A non-leaking dry cellv provided with circuit terminals at both ends comprising a metal cup electrode, a core electrode, means for closing said' cell comprising a non-conducting material closecan so as to compress and seal said sleeve against the underlying portion of said can, said flanged disc having an opening therein through which said Acarbon electrode projects, and a flanged ring member tightly embracing the lower end of said dry cell, the ange on said ring being in crimped relation with the outside walls of said can so as to compress and seal said sleeve against the underlying portion of said can, said flanged ring having an opening in its bottom for exposing the bottom vof said can whereby the same may serve as an electrode.

12. A leakproof dry cell provided with circuit terminals at opposite ends, comprising ,a metal can serving as an electrode and containing an electrolyte, a centrally disposed carbon electrode and depolarizing mix in said electrolyte, a lami- .fnated sheath having an inner layer of thin, flexible, rubbery material which is resistant to penetration by said electrolyte non-adherently embracing the outside walls of said can and an outer layer of non-metallic material towhich said inner layer of rubbery material is adhesively secured, means for closing said can disposed inside thereof, said meansbeing closely embraced by inner side walls of said can and closely embracing the sides of said carbon electrode, a flanged disc tightly embracing the upper end of said dry cell, the flange on said disc being in crimped relation with the outside walls of said 5 can above said means for closing said can so as having an opening therein through which said carbon electrode projects, and a ilansed ring member tightly embracing the lower end of said dry cell, the flange on said ring being in crimped relation with the outside walls of said can so as to compress and seal said sheath against the underlying portion of said can said flanged ring having an opening in its bottom for exposing the bottom of said can whereby the same may serve as anV electrode.

5. In a leakproof dry cell containing an electrolyte, the combination of a metal cup member serving as an electrode, a. laminated sheath having a thin inner layer of flexible, rubbery material which is resistant to penetration by said electrolyte non-adherently embracing the outside walls 8 cup, a flanged disc embracing the upper-.edge of said cup, the nange on said disc being disposed in crimped engagement with the upper edge of said sheath, and a`disc ofy non-conducting material disposed so as to insulate said disc from said cup. v

EDGAR D. McEACI-IRON. EDGAR J. MCEACHRON. GEORGE H. SCHROEDER. HENRY G. FRIANG.

REFERENCES CITED The .following references are of record in the nie of this patent:

2,410,826 Lang et a1 Nov. 12, 194e Certificate of Correction Patent No. 2,541,931 February 13, 1951 EDGAR D. MOEACHRON ET AL. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 39, strike out the Words a flanged metal disc and insert the same after the Word and comma e1eotrode, in line 40; line 55, for the claim numbered 12 read 4; and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the oase in the Patent Oice.

Signed and sealed this 5th day of June, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant Gommzfssz'amar of Patents.

Claims (1)

1. A NON-LEAKING DRY CELL PROVIDED WITH CIRCUIT TERMINALS AT BOTH ENDS COMPRISING A METAL CUP ELECTRODE, A CORE ELECTRODE, MEANS FOR CLOSING SAID CELL COMPRISING A NON-CONDUCTING MATERIAL CLOSELY ENGAGING SAID CORE ELECTRODE AND SAID CUP ELECTREDE, A SLEEVE OF FLEXIBLE, RUBBERY MATERIAL SUBSTANTIALLY IMPERVIOUS TO BE POSSIBLE EXUDATIONS OF SAID DRY CELL NON-ADHERENTLY SHEATHING SAID UP ELECTRODE, A NON-METALLIC COVER SECURED TO AND OVERLYING SAID SLEEVE, A FLANGED RING CLOSELY EMBRACING THE LOWER END OF SAID DRY CELL, THE FLANGE ON SAID RING BEING IN CRIMPING ENGAGEMENT WITH THE LOWER EDGES OF SAID COVER, SAID SLEEVE AND SAID CUP ELECTRODE, THE CRIMPED PORTIONS OF SAID EMBRACING THE UPPER END OF SAID DRY CELL, THE FLANGE ON SAID DISC BEING IN CRIMPED RELATION WITH THE UPPER EDGES OF SAID COVER, SAID SLEEVE, AND SAID CUP ELECTRODE, THE CRIMPED PORTIONS OF SAID FLANGED DISC AND SAID FLANGED RING CAUSING SAID RESILIENT SLEEVE TO BE COMPRESSED BETWEEN SAID COVER AND SAID CUP ELECTRODE SO AS TO FORM A TIGHT PRESSURE-SEAL BETWEEN SAID SLEEVE AND SAID CUP ELECTRODE ADJACENT ITS UPPER AND LOWER ENDS.

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