US3769557A

US3769557A - Electrolytic time delay capsule with plastic cup electrode holder

Info

Publication number: US3769557A
Application number: US00272431A
Authority: US
Inventors: J Jones
Original assignee: COMPULINE CORP
Current assignee: COMPULINE CORP
Priority date: 1972-07-17
Filing date: 1972-07-17
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

An electrolytic timer capsule is constructed of an outer cylindrical closed end case and an inner insulated upside down cup enclosing an electrolyte solution to contact the closed end of the case. The case comprises one electrode and the other is a U-shaped wire extending through the cup with an intermediate section immersed in the electrolyte solution to be etched away until broken. The manufacturing process for the capsule comprises a series of simplified operations comprising insert of the cup into the case, filling with electrolyte and sealing with epoxy resin.

Description

States Patent 1191 Jones, Jr.

[ Oct. 30, 1973 '[22] Filed:

[ ELECTROLYTIC TIME DELAY CAPSULE WITH PLASTIC CUP ELECTRODE HQLDER [75] Inventor: John Paul Jones, Jr., Wayne, Pa.

[73] Assignee: Compuline Corporation, King of Prussia, Pa.

July 17, 1972 21 Appl. No.: 272,431

[52] 11.8. C1. 317/230, 29/570 [51] Int. Cl Hing 9/00 [58] Field of Search 317/230; 29/570 [56] References Cited UNITED STATES PATENTS 8/1958 Hilton 2,932,153 4/1960 Bernard et al. 317/230 3,356,911 12/1967 Galvagni 317/230 3,365,626 l/1968 Mohler et a1. 317/230 Voeten 317/230 Peck 317/230 Primary Examiner-John W. Huckert Assistant Examiner-Andrew J. James Attorney-Laurence R. Brown [5 7 ABSTRACT An electrolytic timer capsule'is constructed of an outer cylindrical closed end case and an inner insulated upside down cup enclosing an electrolyte solution to contact the closed end of the case. The case comprises one electrode and the other is a U-shaped wire extending through the cup with an intermediate section immersed in the electrolyte solution to be etched away until broken. The manufacturing process for the capsule comprises a series of simplified operations comprising insert of the cup into the case, filling with electrolyte and sealing with epoxy resin.

10 Claims, 1 Drawing Figure ELECTROLYTIC TIME DELAY CAPSULE WITH PLASTIC CUP ELECTRODE HOLDER This invention relates to electrolytic timer devices operable to electroplate from a metallic electrode and more particularly it relates to expendible electrolytic timer devices which signify the expiration of a predetermined time period by rupture of the conductive path of an electric conductor and their methods of manufacture. Circuits for such timer devices are described in my U.S. Pat. No. 3,355,731. Prior art timer device construction is typified by my copending application U.S. Ser. No. 106,481 filed Ian. 14, 1971.

If a timer device is expendible it must be simple and low in cost, and yet must be accurate and precise in signifying a predetermined time period. The use of electrolyte solutions under seal require manufacturing techniques to assure long shelf life and operation without leaking, changing physical and performance dimensions or creating operating hazards. In particular construction techniques must be simple and subject to automated assembly to assure uniformity of performance at low cost.

Also the cost of assembly of an expendible timer device is significant and therefore simple and effective configuration of a device (hereinafter referred to as a capsule) is desirable.

It is therefore an object of this invention to provide an improved timer capsule which satisfiesthe foregoing conditions.

A particular object of the invention is to provide a simple-capsule configuration which is inexpensive to manufacture without disturbing the timing accuracy and methods of construction thereof.

The foregoing objectives are realized in accordance with this invention together with further features and advantages by provision of a metallic electrode which is plated away in the form of a single piece of wire having an intermediate portion passed through a plastic cup which receives electrolyte solution. The plastic cup is force fit into an electrode can and has a funnel for receiving electrolyte and serving to seal the electrolyte inside before surrounding with an epoxy.

I A preferred embodiment of the invention is shown in the single FIGURE of the drawing showing a capsule in elevation section view partially to show the constructional features thereof.

In the capsule assembly, an outer copper can 1 serves as one electrode holding an electrolyte solution 2 in which a second electrode in the form of a U-shaped continuous copper wire is inserted. The wire electrode 3 has two end conductor leads 4,5 by which detection is made of the rupture of the U-shaped portion within the electrolyte by plating away on the bottom surface 6 of the can electrode 1 by electrolytic action when a current is passed between the electrodes.

Inside the can electrode 1 is the inverted cup assembly 7 made of polypropylene plastic to hold the electrolyte solution 2. A compression ring 8 is formed by an integral outwardly extending lip about the outer bottom edge conforming in shape to the interior bottom of the can 1 thereby to form a liquid tight seal with the end of the electrode can I exposing only the plating surface 6 at the inner closed end of the cam electrode 1 to the electrolyte 2. The integral seal ring is compressed about 0.020 feet when inserted with the can to form a hermetic seal.

The cup assembly 7 includes a keyway mating structure for orienting the cup position during automated assembly in inserting the electrode wire assembly 4, 5. Thus a precision indented keyway portion 9 is located by means of a rough location finder in the form of indented keyway portion 10 for orientation on automated assembly jigs or the like.

The walls 11 of the cup assembly 7 are tapered to permit the influx of a liquid epoxy sealing solution 12 thereabout without bubbling or voids. The epoxy seal is by this construction isolated from the electrolyte by the seal ring 8 and thus is not subject to deterioration over long shelf storage periods or high operation temperatures from the action of the electrolyte solution 2, which could cause leaks along the sides of the can. Also the seal ring 8 prevents epoxy 12 from fouling the electrode surface 6 during the manufacturing process.

Another feature of the cup assembly 7 is the heat scalable aperture tube 13 to funnel the electrolyte into the cavity 2 between the two cups 1 and 7. This permits injection of electrolyte 2 by a hypodermic needle or the like at the upper mouth entry 14 until it reaches a level 15 at the throat of the funnel tube 13. After the electrolyte 2 is inserted, the mouth 14 of the funnel tube 13 is heat sealed as shown in phantom lines 16 to enclose the electrolyte 2 and entrap an air bubble 17 which permits expansion of the electrolyte without danger of bursting or leakage.

Lead funnels 18 are provided for receiving and passing the ends 4, 5 of the single wire copper electrode unit 3 through the cup bottom 19. A detent tab 20 is coined into the lead to permit the electrode unit 3 to snap into place in the cup and be held therein firmly against the ribbon like U-shaped portion of the electrode unit 3 (described in the aforementioned copending application).

MANUFACTURING METHOD In the first assembly step, the electrode unit 3 is coined or forged from a continuous copper wire, bent into its U-shape and inserted into the inverted cup 7. All units are keyed for orientation and automatic handling with appropriate machinery.

The cup assembly 7 is then pressed into the copper cup electrode 1 to form the hermetic seal at theinterface with compression ring 8.

A first measured epoxy seal charge 12 is then entered into the shell to just cover the leads near the tabs 20 where they pass through the cup assembly bottom 19, so that just enough epoxy can run down around the leads to form a complete seal in the area of lead funnels 18. The epoxy is then cured before further processing.

To insert the electrolyte a dispensing needle is inserted through mouth 14 of the funnel neck 13 and a measured charge is inserted to reach level 15, and as the needle is withdrawn, a heated head presses upon the mouth 14 melting and sealing it closed at 16.

1 Immediately thereafter a further epoxy charge is inserted in region 30 to reach just below the lip 30 of the can electrode l to produce a completely hermetically sealed assembly.

After curing of the epoxy the can electrode 1 is then cleaned by a detergent and the leads and can are electroplated with tin on all exposed portions, after which a final charge 32 of epoxy is inserted to give a finished appearance and to provide a minicus 33 about the leads 4, S. This provides a finished appearance and further assures a complete seal about the leads.

Because a solid copper can 1 and a solid copper wire 3 are used with no dissimilar metals within the active electrolyte area 2 there is no possible deterioration at high temperatures or over long storage periods that could cause a battery effect. Also the mechanical arrangement of the assembly prevents any possible inter nal shorting of the inner leads to the outer case.

What is claimed is:

1. In an electrolytic timer capsule having two electrodes and an electrolyte therebetween, the combination comprising, an outer cup forming a first of said electrodes, an inner cup of plastic material inserted upside down into said electrode to form a cavity confining the electrolyte between said cups, a second electrode comprising a length of wire, and means passing the second of said electrodes through said inner cup with a continuous portion extending into said electrolyte cavity, and two ends extending out of the capsule so that the wire may be electrolytically broken by electric current passed between the electrodes and detected by a .therethrough two wires, and said second electrode comprising abent wire with two free ends extending through said two funnels and held in said base by detent tabs formed in said wire at either end of said aperture funnels in said base.

6. A capsule as defined in claim 1 having mating structure for orienting said inner cup in a known position within said outer cup, and having a detent member on said outer cup in a fixed position.

7. A capsule as defined in claim 1 wherein said second electrode and said outer cup electrode are both of the same metal.

8. A capsule as defined in claim 1 with the inner cup having a rim of a dimension greater than the inner di ameter of the outer cup and inserted upside down in said outer cup by force fit inside said outer cup to form a hermetically sealed cavity between the cups for receiving said electrolyte.

9. A capsule as defined in claim Shaving a scalable aperture tube extending from the bottom of said inner cup for introducing electrolyte into said cavity after said inner cup is force fit into said outer cup.

10. A capsule as defined in claim 1 wherein said continuous portion is U-shaped with the ends disposed away from the bottom of the electrode cup.

Disclaimer 3,769,557.J0hn Paul Jones, J?., Wayne, Pa. ELECTROLYTIC TIME DELAY CAPSULE WITH PLASTIC CUP ELECTRODE HOLDER. Patent dated Oct. 30, 1978. Disclaimer filed Mar. 22, 1974, by the assignee, Oompulz'ne Oowpomtz'on. Hereby enters this disclaimer to claims 1 and 10 of said patent.

[Oflioz'al Gazette J2me 10, 1.975.]

Disclaimer 3,7 69,557.J07m Paul J ones, Jvn, Wayne, Pa. ELECTROLYTIC TIME DELAY CAPSULE WITH PLASTIC CUP ELECTRODE HOLDER. Patent dated Oct. 30, 1973. Disclaimer filed Mar. 22, 1974, by the assignce, Oompulz'ne Owpomtz'on.

Hereby enters this disclaimer to claims 1 and 10 of said patent.

[Ozfi'oial Gazette J2me 10, 1.975.]

Claims

1. In an electrolytic timer capsule having two electrodes and an electrolyte therebetween, the combination comprising, an outer cup forming a first of said electrodes, an inner cup of plastic material inserted upside down into said electrode to form a cavity confining the electrolyte between said cups, a second electrode comprising a length of wire, and means passing the second of said electrodes through said inner cup with a continuous portion extending into said electrolyte cavity, and two ends extending out of the capsule so that the wire may be electrolytically broken by electric current passed between the electrodes and detected by a change of continuity between said two ends.

2. A capsule as defined in claim 1 with said cavity having electrolyte therein extending only partially into said aperture tube to provide an air pocket within said tube, the tube being closed and sealed above said air pocket.

3. A capsule as defined in claim 2 with an epoxy seal deposited between said inner and outer cups to substantially cover the outer portions of said inner cup exposed inside said outer cup.

4. A capsule as defined in claim 1 wherein said plastic cup comprises a member having tapered walls terminating in an integral outwardly projecting view ring of dimensions slightly less than the inner diameter of said outer cup.

5. A capsule as defined in claim 1 having two aperture funnels in the base of said plastic cup for receiving therethrough two wires, and said second electrode comprising a bent wire with two free ends extending through said two funnels and held in said base by detent tabs formed in said wire at either end of said aperture funnels in said base.

8. A capsule as defined in claim 1 with the inner cup having a rim of a dimension greater than the inner diameter of the outer cup and inserted upside down in said outer cup by force fit inside said outer cup to form a hermetically sealed cavity between the cups for receiving said electrolyte.

9. A capsule as defined in claim 8 having a sealable aperture tube extending from the bottom of said inner cup for introducing electrolyte into said cavity after said inner cup is force fit into said outer cup.