US1682995A - Dry cell - Google Patents

Description

DRY CELL Filed Feb. 10, 1927 gwuantot:

Patented Sept. ,4, 1928.. 7'

EDWARD c. swim, or LAKEWOOD, OHIO, ASSIGNOR TO NATIONAL season con rary,

INC., A CORPORATION OF NEW YORK.

DRY CELL.

- Application filed February 10, 1927. Serial No. 167,257.

This invention relates primarily to centering and insulating means for dry cell depolarizing bobbins. More particularly, the invention comprises an improved lnsulating spacer adapted to receive the bottom of the. bobbin and to hold it pos tively 1n central position in the zinc container electrode, while permitting a portion of the bottom of the container to be utilized as actlve electrode surface.

In U. S. Patent 1,585,077, Briggs d scloses a spacer for depolarizing bobbins which has corners for engaging the sidewalls and which carries flexible members for engaging the bobbin. This spacer is commonly'made of an insulating material and as a result a variable amount of electrolytic action occurs between the central electrodeand the bottom of the container. p

I have found that by the use of a skeleton or perforated spacer it is possible to increase the life of the cell due to the fact that a considerable part of the zinc bottom is exposed to chemical action, and expenments have shown that this constructlon not only adds to the life of the cell but gives a greater uniformity of s'er v1ce.

An ob ect of my invention is to produce a dry cell in which the bobbin shall be acto curately centered and which shall have a longer life, due to the fact that a portion of the area of the zinc bottom is used as an electrode. v

This and other objects of my invention will be evident from the following description, taken in connection with the accompanying drawings in which Fig. 1; is a perspective view of a dry cell including the 1m roved spacer, the z1nc cup being partly bro en away; a

Fig. 2 is a vertical section through the cell of Fig. 1;. I

Fig. 3 is a plan view of the spacer as it appears before insertion in a cell; and

Fig. 4 is a view similar to Fig. 3, showing a modified form of spacer.

Referring to Figs. 1 to 3, numeral 1 denotes a mix bobbin inserted in a zinc cup 2 and adapted to be embedded in electrolyte paste, not shown. The spacer 8, in which the present invention resides, comprises preferred form a sheet 4 of suitabl insulating material having tangs .5. The sheet aoioroxiinately the outline and diinscribed in circle having a. diameter approaching the inner diameter of the cup. The rounded corners 6 on the sheet therefore lie closely adjacent to the wall of the cup and lateral movement is prevented. Further, the tangs when upturned define a seat adapted to receive snugly a bobbin of average size. The bobbin is accordingly retained in the desired central position, sinceits seat is positively centered by engagement of the spacer with the 'cellwall.

5 In order to utilize part of the bottom of the container as active electrode surface, I provide the central disc of the spacer with a number of perforations 7. These may be of any convenient size and shape, but I have found thatif they have an area of about one quarter of that of the entire central disc good results in lengthening the life of the battery are obtained and there is no tendency to weaken the spacer to such an extent as to impair its utility in centering the bobbin. s

While the holes may vary in size, shape, number and arrangement, I have found such an arrangement as shown in Fig. 3 very satisfactory. I have illustrated another arrangement in. Fig. 4, in which 3 is a spacer having tangs 5, corners 6' andtriangular holes 8. I may use a large number of small holes evenly distributed over the entire area of the disc. I prefer not to have a hole in the center ofthe disc since the central through this hole against the zinc and cause an internal short circuit. Also, since the protruding end of the electrode of one cell often engages with the bottom of the next cell at the center, it is desirable'that there should be ,no chemical action at the center. In order toreinforce the bottom of the cell the bottom of the cup maybe thickened or reinforced, as described in an ap lication of G. W. Heise and E. AJSchumad ial No. 680,249, filed December 12, 1923.

- The spacer may be placed in the bottom of the zinc cup before pouring in the elec= trolyte paste and inserting the bobbin, but the preferred method of asernbly is as follows: The required amount of paste is poured into the cop the spacer is pushed into the co to a point about one-bald inch below its brim,- and the bobbin is then placed on the spacer and forced into the cup. The paste flows "upward between the electrode might be driven er, Sertangs into operative position about the bobbin. Other procedures are suitable such as inserting it in the cup.

My improved spacer is especially adapted for use with dry cell bobbins not provlded withsurface protecting means. The spacer tends to prevent the bottom of the bobbin.

from crumbling, which frequently occurs when unprotected bobbins are used. The spacer is of course advantageous in other constructions includingwrapped bobbin assemblies. While primarily intended as a spacing and centering. means for small dry cells of the Le Clanche type, the improved spacer may be used with numerous other cells in which similar results are sought.

I am aware that it has been proposed to make the spacers of a pervious m'aterial but in order toexpose the. bottom of the cup to electrolytic action the spacers must be in. serted while wet. Wet pulpboard spacers can not be handled by machinery as dry jute board s acers can. evident that have devised a batter will have as long a life as one emp oyinga wetted pervious spacer, which can be assembled by machinery and which willcenter the bobbin more certainly.

I claim:

1. A galvanic cell comprising a container electrode, a depolarizing bobbin therein, and a spacer comprising a sheet having edge portions ada ted to engage the side walls of the container electrode, said sheet having tangs upturned between the edge portions and adapted to receive the bobbin snugly therebetween, said spacer havin perforations in the portion below the bob in.

' 2. A galvanic cell comprising a container electrode, a depolarizing bobbin therein, a spacer comprising a member with marginal ortions lfying substantially on the circumerence o a circle having a diameter approaching the inner diameter of the con- Thus it will be. which tainer electrode, whereby substantially lateral movement in said c'ontainer electrode is prevented, said member having further marginal portions defining a central area approximating that of the base of the bobbin and adapted to retain the same in such central area, said spacer also having perforaing a thickened bottom, a depolarizing bob-' bin therein, a spacer comprising a generally hexagonal perforated sheet of insulating material shaped to fit snugly within the cup and having tangs thereon at points between the .vertices of. the hexagonal-defining a central seat for the bobbin.

5. A .dry cell comprising a zinc cup having a thickened bottom, a depolarizing bobbin therein, a spacer comprising substantially rigid portions adapted to enga e the side walls of the cup and to fit snugly therein,

and flexible portions adapted to bend up-- wardly about the bobbin and hold it in central position, said spacer being provided with perforations in said rigid portion.

6. dry cell comprising a zinc cup, 8. depolarizing bobbin therein, a spacer comprising a perforated member of relatively stiff insulating material having portions adapted to contact with the side walls of the cup, and flexible portions defining a central seat for the bobbin.

In testimony whereof, I aifi-x my signature.

EDWARD C. SMITH.

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