CA1110723A - Pressure sensitive interrupter - Google Patents
Pressure sensitive interrupterInfo
- Publication number
- CA1110723A CA1110723A CA299,983A CA299983A CA1110723A CA 1110723 A CA1110723 A CA 1110723A CA 299983 A CA299983 A CA 299983A CA 1110723 A CA1110723 A CA 1110723A
- Authority
- CA
- Canada
- Prior art keywords
- cover
- capacitor
- bridge member
- terminals
- tabs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT OF THE DISCLOSURE
A circuit interrupter is provided for an electrical capacitor, wherein an increase in internal pressure causes bulging of the capacitor cover, which is used to break internal electrical connections. Each of a pair of spaced terminals mounted on the cover has an electrical stud projecting through an aperture in an insulating bridge member positioned under the cover and spanning a pair of indentations in the cover.
Connection tabs from a capacitor section project upwardly and are welded to the terminal studs at the underside of the bridge member in such a manner that the tabs can not pass through the apertures. When the cover bulges upward because of an internal pressure increase, the terminals move upward and become spaced from and slightly rotated with respect to the capacitor section.
Also, the connections of the tabs to the terminal studs cause the bulging cover to flex the bridge member upward. The stresses in the weld connections are greatly increased because of both the upward movement of the terminals and the rotation of the terminals.
At a predetermined increase in pressure the combined tension and rotation stresses in the welds cause both welds to rupture, and the bridge member springs back into essentially a level position.
At this level position the tabs and the studs are kept well separated to prevent remake of the circuit or striking of an arc at a broken connection.
A circuit interrupter is provided for an electrical capacitor, wherein an increase in internal pressure causes bulging of the capacitor cover, which is used to break internal electrical connections. Each of a pair of spaced terminals mounted on the cover has an electrical stud projecting through an aperture in an insulating bridge member positioned under the cover and spanning a pair of indentations in the cover.
Connection tabs from a capacitor section project upwardly and are welded to the terminal studs at the underside of the bridge member in such a manner that the tabs can not pass through the apertures. When the cover bulges upward because of an internal pressure increase, the terminals move upward and become spaced from and slightly rotated with respect to the capacitor section.
Also, the connections of the tabs to the terminal studs cause the bulging cover to flex the bridge member upward. The stresses in the weld connections are greatly increased because of both the upward movement of the terminals and the rotation of the terminals.
At a predetermined increase in pressure the combined tension and rotation stresses in the welds cause both welds to rupture, and the bridge member springs back into essentially a level position.
At this level position the tabs and the studs are kept well separated to prevent remake of the circuit or striking of an arc at a broken connection.
Description
L07%3 ~-. 36-CA-3432 This invention relates to an improved pressure sensitive lnterrupter for electrical capacitors and is an improvement over the invention as disclosed in U.S. Patent No. 3,377,510 dated April 9, 1968, Rayno, assigned to the same assignee as -the present invention.
In a typical capacitor, a capacitor roll section is assembled .in a metal can having a metal cover sealed thereto.
Electrical capacitor leads pass from the capacitor roll section in the can through the cover. In such a capacitor, failures result from internal arcing and thermal runaway cause a pressure build-up in the capacitor can. This pressure build-up causes an outward bulging of the cover to such an e~tent that the case or can rupture with the result of fluid spillage Erom the can. Where the fluicl in the capacitor is flammable, a potential fire hazard results.
In the Rayno patent, there is disclosed a pressure sensistive electrical circuit interrupter device combined with an electrical capacitor. The Rayno device utilizes the bulging action of the cover to flex a bridge member which is supported independently of the cover under the cover. The bridge member served as a local connection for a terminal stud extending through the cover and hridge member, and a -tab rising from the capacitor section to join to the stud at the bridge member. Accordingly, during the bulging of the cover the flexible bridge member, by means of the terminal and tab connection, flexes the bridge member until it is under sufficient flexing tension to break the connection which connects the capacitor tab to the terminal thereby interrupting the capacitor circuit through the tab.
It is now desirable to have maximum assurance that the ~ Z~ 36-CA-3432 capacitor is electrically removed from the circuit. Since .
the Rayno device served only to break one capacitor tab connection, the other tab remained connected to the electrical circuit. Under these conditions it is possible to have a short circuit from the capacitor tabs to the ~ :~
can with the attendant danger of remaking the capacitor circuit through the can. On the other hand once the capacitor has been removed from the circuit and begins to cool the internal pressure in the capacitor can subsides and the bulging cover may return towards its initial position.
Under these conditions an arc may be struck between the in-terrupred connection in the capacitor tab and the capacitor reenergized with attendant danger of arcing and fire hazards.
Accordingly, it is a principle object of this invention to adapt the bulging cover concept of the Rayno device to provide separation of a plurality o tabs or leads of an electrical capacitor.
In the practice of one form of this invention, each of a pai.r of spaced terminals of a two terminal capacitor has an electrical stud which projects through an insulat- ,~
ing bridge member positioned at the underside of a cap-acitor cover. The bridge member spans a pair of in-dentations in the cover which serve as fulcrum points or spaced supports for the bridge member. The pair of capacitor terminal studs extend through the cover member and through a pair of spaced apart apertures in the bridge member :
between the fulcrum points. The terminals are positioned along a straight line joining the indentations and are spaced on opposite sides of the center of the capacitor :~
cover. Tab leads from the capacitor section projection upwardly to the underside of the bridge member adjacent the apertures through which the terminal studs project.
~ 36-CA~3433 .
The tabs are joined by welding to -the terminals at the under-side of the bridge member in such a manner that the tabs are not free to pass through the aperture. When the cover bulges due to an internal pressure build-up condition, the terminals follows the movement of the cover and take up a position significantly axially spaced from the capacitor section in the can and slightly rotated with respect to the capacitor can since they are on the slope of the cover.
At the same time a weld connection of the tab to the ter-minal causes the bulging cover to flex the bridge memberin a direction to approximate the curve of the capacitor cover. The stresses in the weld connection are greatly increased because they must not only withstand the bu:Lg-ing of the cover but also the rocking or the rotation oE
the terminals. At a predetermined point in the operation this combined tension and rocking stress in the weld is sufficient to cause the weld to rupture and the bridge member then springs back into essentially a level position.
Consequently as the bridge springs back into its level or unstressed position the space between -the tabs and the studs are maintained in a wide position to provide safety agains-t a remake of the circuit or a striking of an arc. at the broken connection. At the same time both tabs of the capacitor are broken and the capacitor is wholly removed from the electrical circuit.
This invention will be better understood when taken in connection wi-th the following description and the drawings in which:
FIG. 1 is a prior art illustration of a single terminal circuit interrupter of the Rayno patent.
Fig. 2 is a prior art illustratlon of a two terminal capacitor of the Rayno paten-t in which only one terminal circuit is broken.
Fig. 3 is a side elevational view of a two terminal circuit interrupter device of the present invention.
Fig. 4 is a plan view of a bridge member of the two terminal interrupter device of Fig. 3.
Fig. 5 is an elevational view of a capacitor showing the circuit interrupter device of Fig. 3 after it has functioned.
Fig. 6 is a side elevational view of a three terminal circuit interrupter device of the present invention.
Referring now to Figs. 1 through 3 there is shown an electrical capacitor 1 which may be any of the various types of capacitors utilized for fluorescent lighting ballasts, motor start, motor run, and other such capacitors.
These capacitors may be either in a cvclindrical can con-figuration, or as is more common at the moment, in an oval or flattened can 2 configuration. A capacitor roll section !
3 is positioned within the can 2 and submerged in a die electric liquid impregnant. A cover member 4 having ter-minal assemblies 5 and 6 therein is sealed -to the casing 1. ~;
The terminals 5 and 6 are similar and a description of one suffices for both. Each terminal assembly comprises a bushing member 7 made of a resilient material such as silicone rubber through which passes a conductive terminal stud 8 electrically connected at its inner end to a cap-acitor tab or lead such as tab 9. Prong connectors are joined to the external extremity of the stud 8 for external connec-tion to the capaci-tor.
In Fig. 1 the Rayno device was disclosed in connection with the breaking of an electrical circuit at only one terminal. Even with a two terminal design of Fig. 2 only one terminal circuit was broken. A three terminal design - ~ 36-CA~3432 Z3 ~`
would still retain the single circuit breaker concept. ~ne problem was that the underside of the terminals were used as supports on fulcrums, or, in a two terminal design, a dimple support at the location of the absent terminal was used as the fulcrum. Under these conditions the brea]cing of two or three terminal circuits was not feasible. The present invention involves the breaking of at least -two terminal circuits because of the predetermined location of the ter-minals and the use of an improved support of the bridge member.
Referring now to Figs. 3 and 4 a bridge member 11 is positioned adjacent the underside of the cover 4 and rests against a pair of oppositely positioned inwardly projecting supports oE fulcrum memhers 12. In addition each terminal assembly is equidistently spaced from the center of the capacitor or cover.
Referring now to Fig. 4 there is illustrated a plan ;
view of the bridge member 11 of the present invention.
Bridge member 11 is made up of an insulating material for example a plastic material such as a phenolic resin or a resin paper laminate. As illustrated, the bridge member 11 is provided with a pair of spaced apertures 13 which lie directly under the terminals 5 and 6. Terminal studs 8 project through the bridge member in a close but loose fitting relationship with the apertures 13.
Referring again to Fig. 3 the tabs 9 from the capacitor roll section 2 project upwardly and lie underside the apertures 13 in the bridge member 11. At this point the studs 8 which have hemispherical shaped ends are welded to the tabs 9. The hemispherical ends provide a correct and constant weld connection with minimal variation between welds. As illustrated, the tabs 9 overlie the apertures ~ t72 3 36-CA-3432 13 and are thus prevented from being drawn through the apertures 13 in conjunction with the ordinary tensions which are expected to take place.
The operation of this device progresses from Figs. 3 to Fig. 5. Starting from the Fig. 3 device, upon over-pressure conditions in Can 2 there is a pressure build--up which causes -the cover 4 to commence bulging outwardly. As cover 4 commences bulging, the fulcrums 12 which engage the bridge 11 also begin to move outwardly but at a much lower rate and over less distance than the terminal assemblies 5 and 6.
Consequently the bridge member 11 is being pulled or flexed upwardly by the terminal members 5 and 6 while the ends thereof are being restrained by the fulcrums 12. As the cover member 11 continues to move outwardly, the termlnals 5 and 6 which are spaced from the center of the capacitor .
can also begin to rotate or rock slightly to follow the curvature of the cover. The attachment of the terminal studs 8 to the tabs 9 take place through a narrowly con-fining aperture 13. Accordingly the rocking action of the terminal may also add a bending or shear stress in the weld connect.ion to accentuate the breaking of the con-nection. The rapid separation o~ breaking of the connection is facilitated by the use of a weld connection instead of a soldered connection.
The flexibility of the bridge member 11 also con-tributes to the rapid separation of the con-tacts. For exampler a very stiff bridge member may lend sufficient restraining support to the cover so that a breaking of each of the contacts may not take place. Also, a low flexibility bridge member may provide a separation of the contacts so quickly -that there will be no maximum separation of the contact members after the breakage occurs. In the ~ ~ ~ 36-CA-3432 alternative i the bridge member is too flexible, the contacts will remain unbroken at the maximum bulging of the cover or so n~ar that point that the capacitor can may still rupture. With the terminals placed off center as in this in~ention, the distance of travel of a terminal on a bulging cover is limited, compared with the distance of travel of a terminal in the center of a bulging cover. By placing the terminals equicListantly off center and correlating the ~eld connections with the flexibility of the bridge, a quick break and maximum separation at both connection~
L0 can be provided.
It has also been discovered that this invention is applicable to break the leads for three terminals as well as for two terminals without any additional design criteria. With the three terminal conEiguration as illustrated in Fig~ 6, terminal 1~ is positioned in the center o the cover, and terminals 5 and 6 are positioned equidistantly on opposite sides of the center.
Under these conditions, when the co~er 4 bulges, the central terminal 14 is the one that rises first and progresses through the greatest distance. The central terminal 14 will then have flexed the bridge sufficiently to break the center tab connection before the tab connections break at the outer terminals. However, when the tab connection of the central terminal 14 breaks, the entire flexing stress must then be carried by the tab connections of the two outer terminals 5 and 6. This additional stress placed on the two outer tab connections causes them to break substantially simultaneously. Accordingly, it can be seen that the same design criteria and thé same flexing s~resses involved, in the two terminal capacitor can be utilized to break the connections in a three terminal capacitor. In the breakage sequence for the three terminal capacitor, however, breaking of the tab for the central terminal occurs first, followed by nearly simultaneous breaking of the tabs for the two outer terminals.
. .
In one preferred form of this invention~ the capacitor has an oval cross-section, with the length of the cover being about 2.75 inches and the width of the cover being about 1.75 inches. The cover and the case may be made of either steel or aluminum. With steel the thickness is from about 0.012 to about 0.016 inch, and with aluminum it is frorn about 0~020 to about 0.025 inch. The bridge member is a phenolic resin strip about 2.5 inches in length, about 0.8 inch in width and from about 0.060 to about 0.064 inch thick. The fulcrum mer~ers are located close to the outer extremity of the cover and project downwardly about 0.08 inch. ;
'~:',.
In a typical capacitor, a capacitor roll section is assembled .in a metal can having a metal cover sealed thereto.
Electrical capacitor leads pass from the capacitor roll section in the can through the cover. In such a capacitor, failures result from internal arcing and thermal runaway cause a pressure build-up in the capacitor can. This pressure build-up causes an outward bulging of the cover to such an e~tent that the case or can rupture with the result of fluid spillage Erom the can. Where the fluicl in the capacitor is flammable, a potential fire hazard results.
In the Rayno patent, there is disclosed a pressure sensistive electrical circuit interrupter device combined with an electrical capacitor. The Rayno device utilizes the bulging action of the cover to flex a bridge member which is supported independently of the cover under the cover. The bridge member served as a local connection for a terminal stud extending through the cover and hridge member, and a -tab rising from the capacitor section to join to the stud at the bridge member. Accordingly, during the bulging of the cover the flexible bridge member, by means of the terminal and tab connection, flexes the bridge member until it is under sufficient flexing tension to break the connection which connects the capacitor tab to the terminal thereby interrupting the capacitor circuit through the tab.
It is now desirable to have maximum assurance that the ~ Z~ 36-CA-3432 capacitor is electrically removed from the circuit. Since .
the Rayno device served only to break one capacitor tab connection, the other tab remained connected to the electrical circuit. Under these conditions it is possible to have a short circuit from the capacitor tabs to the ~ :~
can with the attendant danger of remaking the capacitor circuit through the can. On the other hand once the capacitor has been removed from the circuit and begins to cool the internal pressure in the capacitor can subsides and the bulging cover may return towards its initial position.
Under these conditions an arc may be struck between the in-terrupred connection in the capacitor tab and the capacitor reenergized with attendant danger of arcing and fire hazards.
Accordingly, it is a principle object of this invention to adapt the bulging cover concept of the Rayno device to provide separation of a plurality o tabs or leads of an electrical capacitor.
In the practice of one form of this invention, each of a pai.r of spaced terminals of a two terminal capacitor has an electrical stud which projects through an insulat- ,~
ing bridge member positioned at the underside of a cap-acitor cover. The bridge member spans a pair of in-dentations in the cover which serve as fulcrum points or spaced supports for the bridge member. The pair of capacitor terminal studs extend through the cover member and through a pair of spaced apart apertures in the bridge member :
between the fulcrum points. The terminals are positioned along a straight line joining the indentations and are spaced on opposite sides of the center of the capacitor :~
cover. Tab leads from the capacitor section projection upwardly to the underside of the bridge member adjacent the apertures through which the terminal studs project.
~ 36-CA~3433 .
The tabs are joined by welding to -the terminals at the under-side of the bridge member in such a manner that the tabs are not free to pass through the aperture. When the cover bulges due to an internal pressure build-up condition, the terminals follows the movement of the cover and take up a position significantly axially spaced from the capacitor section in the can and slightly rotated with respect to the capacitor can since they are on the slope of the cover.
At the same time a weld connection of the tab to the ter-minal causes the bulging cover to flex the bridge memberin a direction to approximate the curve of the capacitor cover. The stresses in the weld connection are greatly increased because they must not only withstand the bu:Lg-ing of the cover but also the rocking or the rotation oE
the terminals. At a predetermined point in the operation this combined tension and rocking stress in the weld is sufficient to cause the weld to rupture and the bridge member then springs back into essentially a level position.
Consequently as the bridge springs back into its level or unstressed position the space between -the tabs and the studs are maintained in a wide position to provide safety agains-t a remake of the circuit or a striking of an arc. at the broken connection. At the same time both tabs of the capacitor are broken and the capacitor is wholly removed from the electrical circuit.
This invention will be better understood when taken in connection wi-th the following description and the drawings in which:
FIG. 1 is a prior art illustration of a single terminal circuit interrupter of the Rayno patent.
Fig. 2 is a prior art illustratlon of a two terminal capacitor of the Rayno paten-t in which only one terminal circuit is broken.
Fig. 3 is a side elevational view of a two terminal circuit interrupter device of the present invention.
Fig. 4 is a plan view of a bridge member of the two terminal interrupter device of Fig. 3.
Fig. 5 is an elevational view of a capacitor showing the circuit interrupter device of Fig. 3 after it has functioned.
Fig. 6 is a side elevational view of a three terminal circuit interrupter device of the present invention.
Referring now to Figs. 1 through 3 there is shown an electrical capacitor 1 which may be any of the various types of capacitors utilized for fluorescent lighting ballasts, motor start, motor run, and other such capacitors.
These capacitors may be either in a cvclindrical can con-figuration, or as is more common at the moment, in an oval or flattened can 2 configuration. A capacitor roll section !
3 is positioned within the can 2 and submerged in a die electric liquid impregnant. A cover member 4 having ter-minal assemblies 5 and 6 therein is sealed -to the casing 1. ~;
The terminals 5 and 6 are similar and a description of one suffices for both. Each terminal assembly comprises a bushing member 7 made of a resilient material such as silicone rubber through which passes a conductive terminal stud 8 electrically connected at its inner end to a cap-acitor tab or lead such as tab 9. Prong connectors are joined to the external extremity of the stud 8 for external connec-tion to the capaci-tor.
In Fig. 1 the Rayno device was disclosed in connection with the breaking of an electrical circuit at only one terminal. Even with a two terminal design of Fig. 2 only one terminal circuit was broken. A three terminal design - ~ 36-CA~3432 Z3 ~`
would still retain the single circuit breaker concept. ~ne problem was that the underside of the terminals were used as supports on fulcrums, or, in a two terminal design, a dimple support at the location of the absent terminal was used as the fulcrum. Under these conditions the brea]cing of two or three terminal circuits was not feasible. The present invention involves the breaking of at least -two terminal circuits because of the predetermined location of the ter-minals and the use of an improved support of the bridge member.
Referring now to Figs. 3 and 4 a bridge member 11 is positioned adjacent the underside of the cover 4 and rests against a pair of oppositely positioned inwardly projecting supports oE fulcrum memhers 12. In addition each terminal assembly is equidistently spaced from the center of the capacitor or cover.
Referring now to Fig. 4 there is illustrated a plan ;
view of the bridge member 11 of the present invention.
Bridge member 11 is made up of an insulating material for example a plastic material such as a phenolic resin or a resin paper laminate. As illustrated, the bridge member 11 is provided with a pair of spaced apertures 13 which lie directly under the terminals 5 and 6. Terminal studs 8 project through the bridge member in a close but loose fitting relationship with the apertures 13.
Referring again to Fig. 3 the tabs 9 from the capacitor roll section 2 project upwardly and lie underside the apertures 13 in the bridge member 11. At this point the studs 8 which have hemispherical shaped ends are welded to the tabs 9. The hemispherical ends provide a correct and constant weld connection with minimal variation between welds. As illustrated, the tabs 9 overlie the apertures ~ t72 3 36-CA-3432 13 and are thus prevented from being drawn through the apertures 13 in conjunction with the ordinary tensions which are expected to take place.
The operation of this device progresses from Figs. 3 to Fig. 5. Starting from the Fig. 3 device, upon over-pressure conditions in Can 2 there is a pressure build--up which causes -the cover 4 to commence bulging outwardly. As cover 4 commences bulging, the fulcrums 12 which engage the bridge 11 also begin to move outwardly but at a much lower rate and over less distance than the terminal assemblies 5 and 6.
Consequently the bridge member 11 is being pulled or flexed upwardly by the terminal members 5 and 6 while the ends thereof are being restrained by the fulcrums 12. As the cover member 11 continues to move outwardly, the termlnals 5 and 6 which are spaced from the center of the capacitor .
can also begin to rotate or rock slightly to follow the curvature of the cover. The attachment of the terminal studs 8 to the tabs 9 take place through a narrowly con-fining aperture 13. Accordingly the rocking action of the terminal may also add a bending or shear stress in the weld connect.ion to accentuate the breaking of the con-nection. The rapid separation o~ breaking of the connection is facilitated by the use of a weld connection instead of a soldered connection.
The flexibility of the bridge member 11 also con-tributes to the rapid separation of the con-tacts. For exampler a very stiff bridge member may lend sufficient restraining support to the cover so that a breaking of each of the contacts may not take place. Also, a low flexibility bridge member may provide a separation of the contacts so quickly -that there will be no maximum separation of the contact members after the breakage occurs. In the ~ ~ ~ 36-CA-3432 alternative i the bridge member is too flexible, the contacts will remain unbroken at the maximum bulging of the cover or so n~ar that point that the capacitor can may still rupture. With the terminals placed off center as in this in~ention, the distance of travel of a terminal on a bulging cover is limited, compared with the distance of travel of a terminal in the center of a bulging cover. By placing the terminals equicListantly off center and correlating the ~eld connections with the flexibility of the bridge, a quick break and maximum separation at both connection~
L0 can be provided.
It has also been discovered that this invention is applicable to break the leads for three terminals as well as for two terminals without any additional design criteria. With the three terminal conEiguration as illustrated in Fig~ 6, terminal 1~ is positioned in the center o the cover, and terminals 5 and 6 are positioned equidistantly on opposite sides of the center.
Under these conditions, when the co~er 4 bulges, the central terminal 14 is the one that rises first and progresses through the greatest distance. The central terminal 14 will then have flexed the bridge sufficiently to break the center tab connection before the tab connections break at the outer terminals. However, when the tab connection of the central terminal 14 breaks, the entire flexing stress must then be carried by the tab connections of the two outer terminals 5 and 6. This additional stress placed on the two outer tab connections causes them to break substantially simultaneously. Accordingly, it can be seen that the same design criteria and thé same flexing s~resses involved, in the two terminal capacitor can be utilized to break the connections in a three terminal capacitor. In the breakage sequence for the three terminal capacitor, however, breaking of the tab for the central terminal occurs first, followed by nearly simultaneous breaking of the tabs for the two outer terminals.
. .
In one preferred form of this invention~ the capacitor has an oval cross-section, with the length of the cover being about 2.75 inches and the width of the cover being about 1.75 inches. The cover and the case may be made of either steel or aluminum. With steel the thickness is from about 0.012 to about 0.016 inch, and with aluminum it is frorn about 0~020 to about 0.025 inch. The bridge member is a phenolic resin strip about 2.5 inches in length, about 0.8 inch in width and from about 0.060 to about 0.064 inch thick. The fulcrum mer~ers are located close to the outer extremity of the cover and project downwardly about 0.08 inch. ;
'~:',.
Claims (5)
1. An electrical capacitor comprising in combination:
(a) a capacitor can having a capacitor section sealed therein, (b) a cover sealingly attached to said can to seal said capacitor section therein in liquid-tight relationship, (c) a pair of terminals in said cover and extending therethrough, said terminals being spaced equidistantly on opposite sides of the center of said cover, (d) a predeterminedly flexible insulating strip bridge member adjacent the underside of said cover, (e) a pair of fulcrums adjacent the outer extremity of said cover and restraining said bridge member from upward movement, (f) said bridge member extending across said fulcrums and having a pair of apertures through said bridge member in alignment with said terminals, (g) a stud in each of said terminals extending loosely through a corresponding one of said apertures, (h) a pair of tabs electrically connected to said capacitor section and extending up to said bridge member at said apertures, (i) each of said tabs being formed to prevent axial movement thereof through its corresponding aperture, (j) a welded electrical shear connection joining each of said tabs to a corresponding one of said studs below said bridge member, (k) said bridge member being characterised by having significant transverse flexibility between said fulcrums so that when said cover bulges because of increased pressure in said can the resulting movement of said terminals and their connections to said tabs flexes the bridge member in the direction of the bulging of the cover until a predetermined stress is encountered in the shear connections and said connections are broken and the bridge member returns to its unflexed condition.
(a) a capacitor can having a capacitor section sealed therein, (b) a cover sealingly attached to said can to seal said capacitor section therein in liquid-tight relationship, (c) a pair of terminals in said cover and extending therethrough, said terminals being spaced equidistantly on opposite sides of the center of said cover, (d) a predeterminedly flexible insulating strip bridge member adjacent the underside of said cover, (e) a pair of fulcrums adjacent the outer extremity of said cover and restraining said bridge member from upward movement, (f) said bridge member extending across said fulcrums and having a pair of apertures through said bridge member in alignment with said terminals, (g) a stud in each of said terminals extending loosely through a corresponding one of said apertures, (h) a pair of tabs electrically connected to said capacitor section and extending up to said bridge member at said apertures, (i) each of said tabs being formed to prevent axial movement thereof through its corresponding aperture, (j) a welded electrical shear connection joining each of said tabs to a corresponding one of said studs below said bridge member, (k) said bridge member being characterised by having significant transverse flexibility between said fulcrums so that when said cover bulges because of increased pressure in said can the resulting movement of said terminals and their connections to said tabs flexes the bridge member in the direction of the bulging of the cover until a predetermined stress is encountered in the shear connections and said connections are broken and the bridge member returns to its unflexed condition.
2. The capacitor of claim 1, wherein said can comprises an oval-like cross-section and said bridge member and said terminals extend along the longer dimension thereof.
3. The capacitor of claim 1, wherein said fulcrums are indentations in said cover.
4. The capacitor of claim 2, wherein three such terminals are located in said cover, one of said terminals being in the center of said cover and the other two terminals being equidistantly spaced on opposite sides of the center of said cover.
5. The capacitor of claim 1, wherein said can comprises a circular cross-section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA299,983A CA1110723A (en) | 1978-03-29 | 1978-03-29 | Pressure sensitive interrupter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA299,983A CA1110723A (en) | 1978-03-29 | 1978-03-29 | Pressure sensitive interrupter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1110723A true CA1110723A (en) | 1981-10-13 |
Family
ID=4111104
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA299,983A Expired CA1110723A (en) | 1978-03-29 | 1978-03-29 | Pressure sensitive interrupter |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1110723A (en) |
-
1978
- 1978-03-29 CA CA299,983A patent/CA1110723A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |