Chemistry: electrical current producing apparatus – product – and – Preserving cell in storage feature
Reexamination Certificate
2000-10-19
2001-12-11
Brouillette, Gabrielle (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Preserving cell in storage feature
C429S065000, C429S098000, C429S163000
Reexamination Certificate
active
06329095
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to removable tabs which cover air holes on the cathode casing of a metal/air cell, particularly the air holes of a miniature zinc/air cell.
BACKGROUND OF THE INVENTION
Zinc/air cells are typically in the form of button cells which have particular utility as batteries for electronic hearing aids including programmable type hearing aids. Such miniature cells typically have a disk-like cylindrical shape of diameter between about 4 and 12 mm and a height between about 2 and 6 mm. The miniature zinc/air button cell typically comprises an anode casing (anode cup), and a cathode casing (cathode cup). The anode casing and cathode casing typically each have a closed end and an open end. An electrical insulating material can be placed around the outside surface of the anode casing. After the necessary materials are inserted into the anode and cathode casings, the open end of the anode casing is typically inserted into the open end of the cathode casing and the cell sealed by crimping. The cathode casing can typically be of nickel plated steel or nickel plated stainless steel, for example, with the nickel plate forming the cathode casing's outside surface and stainless steel forming the casing's inside surface. The cathode casing characteristically has at least one, and more usually a plurality of small air holes in the surface at the closed end thereof. This end typically also forms the cell's positive terminal.
A removable tab can be adhered to the cell surface containing the air holes. The tab is conventionally formed of a single material, such as a plastic film which is coated on one side with a releasable pressure sensitive adhesive. The tab is pressed onto the cell surface to cover the air holes therein. The tab has a small extended portion which the user grasps by finger tip when it is desired to remove the tab from the cell. Conventional tabs are designed with the extended free portion for grasping being very small, for example, about ⅛ to ¼ inch. It was generally thought that such small tabs are adequate. However, user satisfaction surveys conducted by the Applicant revealed that many elderly users or dexterity impaired users can have some difficulty grasping the conventional tabs. However, larger tabs if formed in the same manner as conventional tabs, are more apt to be dislodged during handling and shipment of the cells, thereby possibly causing premature activation of some of the cell.
Accordingly, it is desirable to provide removable tabs for metal/air cells, particularly miniature zinc/air cells, which tabs are easier to grasp and remove from the cell.
It is also desirable to provide removable tabs that adhere better and more uniformly to the metal/air cell surface to reduce the chance of air seepage or premature dislodgment from the cell.
SUMMARY OF THE INVENTION
Metal air cells, particularly miniature zinc/air button cells have a removable tab covering air holes in the cell surface. The air holes typically are formed in the closed end of the cathode casing of the cell, which also forms the cell's positive terminal. Such cells are commonly employed as batteries for hearing aids, including programmable hearing aids. The cells typically have a disk-like cylindrical shape (button cells), having a diameter between about 4 and 12 mm and a height between about 2 and 6 mm.
An aspect of the invention is directed to providing a improved removable tab which adheres more uniformly to the cell's surface containing the air holes thereby tightly covering the air holes until the cell is ready for use. The improved tab comprises an elongated member which forms the tab body. The elongated member is desirably fairly rigid or stiff, that is, remains straight and does not bend under its own weight. Such elongated member can be formed, for example, of polyester material. The tab is characterized by having a portion of the tab covering and adhering to the cell (the contact portion) and a remaining portion forming an integral handle which remains unattached to the cell. The tab of the invention is longer than conventional, thus providing a longer handle portion. The handle portion of the tab extends preferably between about ½ and ¾ inches (12.7 mm and 19.1 mm) from the edge of the cell closest to the handle. The tab having such extended handle allows the user to more readily grasp the tab by its handle and remove it from the cell thereby exposing the air holes and activating the cell. The extended tab of the invention provides an advantage particularly to elderly or dexterity handicapped users who may have difficulty grasping conventional tabs. Additionally, the extended tab of the invention allows for stronger adhesive bonding between the tab and cell surface containing the air holes. This is possible because less force is needed to remove the tab from the cell due to the leveraged effect of the extended tab.
Another aspect of the invention is directed to providing a layer of resilient material to the tab in the area of contact between the tab and cell surface containing the air holes. The resilient material can be an elastomeric or spongy material. The resilient material is preferably a polymeric foam material which can be coated with a permanent adhesive on one side to permanently adhere the resilient material to the underside of the tab body at the contact tab contact end. The exposed surface of the resilient material can then be coated with a releasable pressure sensitive material. The contact end of tab is pressed onto the cell surface containing the air holes with the releasable adhesive providing a tight adhesive seal between the tab and cell surface. The polymeric foam can be predominantly open cell or closed cell, preferably closed cell foam. In particular, the additional layer can be polymeric foam such as a polyethylene foam. The polymeric foam desirably has a thickness of between about 0.010 and 0.040 inches (0.25 and 1.02 mm), preferably between about 0.015 and 0.040 inches (0.38 and 1.02 mm). The foam material, particularly, a polyethylene foam allows the tab contact portion to conform more readily to the cell end surface which can be flat or outwardly curved or contain grooves or other surface irregularities in addition to the air holes. The foam material allows the tab contact area having pressure sensitive adhesive applied thereto to be enlarged to also cover depressed or beveled annular rings surrounding the cell end surface. Thus, the addition of a resilient foam layer generally provides closer conformity and more uniform adhesion of the tab to the cell surface containing the air holes.
In another aspect of the invention a portion of the surface of polymeric foam layer can be adhered to the underside of the elongated tab body and a polymeric film can be adhered on one side to another portion of the surface of the foam layer so that the foam layer is between the tab body and polymeric film. The opposite side of the polymeric film can in turn be coated with a releasable pressure sensitive adhesive. When the tab is applied to the cell, the polymeric film adheres to the cell surface and together with the polymeric foam covers the air holes. A tight seal over the air holes is thereby provided. When the tab is lifted, it releases cleanly without leaving residue behind on the cell surface.
REFERENCES:
patent: 4380576 (1983-04-01), Yoshida
Prior art product sample: Duracell 312 Hearing Aid Battery (4-pack) (1999).
Clark William I.
Farnworth David
Siefert Robb K.
Tay George I.
Brouillette Gabrielle
Douglas Paul I.
Josephs Barry D.
Krivulka Thomas G.
The Gillette Company
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