US2677738A

US2677738A - Circuit interrupter

Info

Publication number: US2677738A
Application number: US298108A
Authority: US
Inventors: Hans P Schneider
Original assignee: McGraw Electric Co
Current assignee: McGraw Electric Co
Priority date: 1952-07-10
Filing date: 1952-07-10
Publication date: 1954-05-04
Anticipated expiration: 1971-05-04

Description

May 4, 1 954 H. P. SCHNEIDER CIRCUIT INTERRUPTER Filed July 10, 1952 INVENTOR. Hana 1 6'0 neider fill r-n57 Patented May 4, 1954 UNITED STATES PATENT OFFICE CIRCUIT INTER-RU? TER Application July 10, 1952, Serial No. 298,108

Claims. 1

This invention relates to circuit interrupters and especially pertains to a combination fuse cutout. and load. break. switch construction.

It is an object of the present invention to provide a circuit interrupter comprising in combinationv a conventional fuse link and a load break portion whichv are positioned in a cooperative arrangement. with the. bore of an arc-extinguishing. cartridge unit, which cartridge is readily inte-rchangeable with conventional circuit interrupter cartridges.

It is a specific object of the present invention to provide an interchangeable cartridge for a circuit interrupter having contained within its bore auxiliary load break contacts, one of said contacts being in flexible electrical connection with a. conventional fuse link connected with line, and the other contact being connected through a conducting. ferrule on the cartridge to complete the electrical connection with line; the cooperating elements of. the cartridge being arranged to provide both an overload protective device and a means for disconnecting a line under load conditions which may be restored for normal closed circuit operating conditions without deleteriously affecting the fuse link.

A-n embodiment of the invention is disclosed in the accompanying drawing, in which Fig. 1 is a side elevation of the invention showing the combination fuse cutout and load break switch in normal operating position.

Fig. 2 is a fragmentary View of a portion of the operating structure disclosing in detail, the external contact-making means.

Although the novel interrupter cartridge may be interchangeable with practically any conventional fuse cutout tube, the accompanying drawing discloses the preferred arrangement, wherein the device comprises upper and lower stationary terminals indicated generally by the reference characters l and 2 which are suitably mounted in spaced. relationship upon an elongated insulator 3. The insulator is supported from any suitable support. by means of bracket 4. The novel interrupter cartridge assembly 5 comprises a tube member 5 joining the terminals I and'z. The tube is preferably constructed of a. fiber-lined Bakelite structure as will be hereinafter described. The cartridge assembly 5 may be secured in position to a bracket 1 by means of a set screw 8 and a clamping nut and bolt assembly 9. The cartridge 5' and its supporting bracket l are pivotally supported at one end of a bifurcated hinge member 1-0 by means of a pivot pin H.

The hinge member In terminates in an eyelet portion l2 which facilitates withdrawal and as sembly of the cartridge with a hook stick (not shown), as will hereinafter be explained. The hinge member is detaohably and pivotally positioned on the hook-like portion l3 of the lower terminal member 2 by means of a trunnion pin It. The lower contact I5 is comprised of a series of leaf springs, which also serve to bias the hinge member If) in a counterclockwise direction about the trunnion M. It will be apparent that the above-described structural arrangement provides a double pivoted assembly to permit downward and outward rocking motion, which will permit dropout disconnection of the cartridge 5 from contact with the upper terminal 1 either on rupture of the fuse link or on disconnection as will be described. along with the operating description of. the invention.

The upper terminal member I may consist of a structure specifically illustrated in Fig. 2 and comprising spaced resilient contact arms I6 which have been specifically illustrated and described in Patent No. 2,331,846, issued on October 12, 1943, to W. O. Schultz, and assigned to the same assignee as is the present invention.

The contact arms [6 are spaced apart and are held in their relative position by a clamping member H. The resilient arms it are slightly outwardly flared and are formed with downwardly turned hook-like portions [8. The hooklilze portions iii are adapt-ed to normally receive outwardly projecting ears or arms It integral with the cartridge assembly 5. Both the upper and lower contacts I and 2,. respectively, provide a means of biasing the cartridge towards downward and outward rocking motion. Suitable electrical connection to the terminals is made through the connectors 20 and M respectively.

The novel cartridge assembly 5' comprises, in detail, the tube 6 normally joining the terminals i and 2. The tube is preferably constructed of a fiber-lined Bakelite structure. The fiber liner 25' is preferably of arc-extinguishing material that will act to quench and de-ionize any arcs occurring within the bore of the tube 6. The sleeve 26 of Bakelite or other suitable material, is utilized. as a means of adding strength to the elongated tube. The upper end of the cartridge 5 is fitted with a conducting. metallic ferrule 21 which. acts to electrically connect the upper terminal to the various components contained within the bore of the tube. The ferrule 21 is provided with an integral bracket member 28, which is adapted to receive a pivot pin 29. A manipulating eyelet 3'0 is pivotally mounted upon the pin 29. The eyelet 30 is provided with a shoulder portion 3|, which is engaged by a biasing spring member 32. The eyelet 3i) is thereby normally biased toward rotationv in a counterclockwise direction. A tongue, or latching more ber 33, integral with the eyelet, protrudes into the bore of the tube 5 through a flared opening 34 in the wall of the ferrule 2'].

The load break portion of the interrupter comprises a truncated conical-shaped arcing contact 35 which normally engages the tongue 33 of the eyelet 30, and is normally held in electrical en gagement with the bore surface of the ferrule 21. A stud member 33 extends from the upper surface of the contact 35, and is threadingly engaged with an insulating follower rod 31. The follower rod may be comprised of a material such as fiber or Lucite. Both of these materials will act to quench and extinguish arcs, and will not carbonize. The opposite end of the follower rod 31 is provided with a stop 38, which may con sist of a threaded bolt and washer combination, as shown, or a bolt with a head portion of a diameter large enough to provide a stopping means with the upper end of the ferrule 2?. The upper end of the ferrule is reduced in diameter to receive a protective removable cap 39 which may be plastic or of any suitable material capable of being molded or drawn to an elongated cup-likc member. This cap 39 acts as a means for protecting the working parts from the elements. The cap 3.! is made removable in order to permit access to the operating elements of the cartridge.

The opposite end of the movable contact 35 is fastened to a flexible spring tensioned conducting lead member 40 through a terminal member 41. The opposite end of the conducting lead it ter minates in a terminal member 42. The members 4! and 42 are normally biased towards one another by a helical spring 43 positioned circumjacently of the conducting lead 46. The member 42 is adapted to receive one end of a conventional fuse link 44. The fuse link 44 may be re" leasably fastened, to the member 42 by means of a threaded contact 45 joining a contact member 46 projecting from the member 42 by means of a machine screw 41. However, it will be obvious that any of many releasable arangements may be provided to function equally as well. For instance, the contact 45 of the fuse link 44 might be threaded to engage a threaded opening in the member 42 (not shown).

The fuse link 44 may take any of the usual forms and is provided with a fusible section 48 having a conducting leader 49 extending therefrom. The leader 49 extends downwardly through the bore of the tubes 6 and upwardly through the bifurcated hinge member if! to a bindingpost terminal 58 provided with a thumb nut 51 screwed on a threaded pin rigid with the hinge member Ill.

Thus, the entire operating assembly contained within the bore of the tube 6 is held in tension against the resilient action of the helical spring 43 by fastening the free end of the leader 49 on the c1amping-post 53 with the aid of the thumb screw 5|. The upper, or load break portion of the mechanism, as stated previously, includes the truncated conical-shaped arcing contact 35 which is engaged at its truncated portion by the latching tongue 33, which also forces the contact towards good electrical engagement with the conducting ferrule 27. Fig. 1 illustrates the novel co-operating assembly in its normal operating position as above described. Electrical connection is provided through the resilient contact arms I6 of the upper terminal member I to the conducting ferrule 2i, through the contact 35 attached to the conducting leader 43, and thereby continued through the fuse link 44 to the hinge member 10 of the lower terminal 2.

The device operates as follows: When the device is to be operated as a load break switch, a hook or switch stick (not shown) is inserted in the manipulating eyelet 30, and is pulled in a downward and outward direction. The downward motion on the eyelet 30 will cause it to pivot in a clockwise direction, thereby releasing the engagement between the latching tongue 33 and the contact 35. Since the contact is biased in a downward direction, as shown in Fig. l, by the helical spring 33 circumjacent to the conducting lead 49, the electrical connection between the contact 35 and the ferrule 2'! will be severed. Any arcs that may be created from disengagement of these contacts under load conditions will be drawn within the bore of the tube 6, where they may be properly extinguished. Since the tube 6 is lined with a fiber liner 25, the arc will act upon the bore of this liner and will be rapidly quenched and. tie-ionized. As the contact continues to move in a downward direction, it will carry along its follower rod 37, which rod will act to confine the are within the bore of the tube where it may be properly extinguished. The follower rod 3? may be made of horn fiber or Lucite, or other suitable material which do not carbonize under arcing conditions.

Concurrently with the separation of the movable contact and ferrule 2'5, and preferably momentarily thereafter, the cartridge assembly '5 will pivot downwardly and outwardly about its pivot points i! and i l on the hinge member ID as tension is released on the leader 49 by separation of the contacts. It will be apparent that the latching arrangement provided between the contact ears Ii,- on the ferrule 2! and the hooklike portion 58 of the resilient contacts l6 will be released to permit outward motion about the trunnion M of the lower terminal member 2. The operating assembly contained within the bore of the cartridge 5 will be prevented from. withdrawing completely from the bore by engagement of the stop 38 on the follower 31 with the upper surface of the ferrule 27.

When it is desired to again establish electrical connection between the terminals l and 2, the cartridge assembly is reset in normal operating position. This may be done by inserting the hook portion of a switch stick in the eyelet i2 and removing the unit from the hook portion l3 of the lower terminal member 2. The operator first removes the cap 39 from the upper extremity of the cartridge assembly 5. As shown, the cap threadingly engages the ferrule 2'5, but may be a press fit with the ferrule if so desired. After the cap is removed, the stop 38 is grasped and pulled in a tensioning direction against the biasing action of the spring 43 to reset the latching tongue 33 of the eyelet 33 in engagement with the movable contact 35 to the position shown in Fig. l. The protective cap 39 is replaced on the cartridge, and the assembly is reset with the trunnions l 4 inserted in the hook-like portion i3 of the lower terminal member 2. The switch stick (not shown) is now inserted in the eyelet 30 of the cartridge, and the cartridge assembly 5 is pivoted about the trunnion i l in a counterclockwise direction to engage the ears [9 with the hook-like portion 13 of the resilient contact 16 of the upper terminal member I. The unit 5' is. not established. in normal operating: position.

The operation of: the apparatus under overload is as follows: When an overload occurs, the fuse link Mi is ruptured at the fusible portion 58 and the helical spring it acts" to draw the ruptured. sections apart from one another. Any arcs created under this overload condition will be properly extinguished within the confines of thetube: 6, as above-described in connection with disconnection' under nor-.nal load conditions. The: lead-r er 49 is expelled downwardly and the weight of the fuse tube and its associated parts,aswell1 as release of the spring tension, bias the cartridge toward downward motion. It is apparent, therefore, that when the fuse link is ruptured, the" cartridge positioned on dual pivot members H and M will rock downwardly and outwardly to detach itself from the latching hook like: portion [-8 of the resilient members it of the upper terminal members i. The cartridge with its-ruptured link, will drop downwardly to hang in a vertical position away from the upper contact (not shown).

In the blown position it is obvious that the cartridge assembly 5 may be lifted from the hook supports it by means or" a switch stick; co-acting with the eyelet portion ii? of the hinge member H). The fuse tube may then be re-fused at the junction of the contact 48' and G5, with electrical connection being completed as shown in Fig. 1, and particularly described in connection with the above load break operatin description.

It will be seen that a novel form of a circuit interrupter has been provided which has both automatic and manual operation responding to an overload in an automatic manner and capable of being operated manually to interrupt the circuit under load without damage to the cutout. It is also to be seen that the composite fuse link is not destroyed when the cutout is manually opened under load as the same fuse'link is again put in service as described in the above.

I claim:

1. In a circuit interrupter including first and second stationary terminals, an interrupter assembly having an arc-extinguishing chamber, said assembly normally electrically connecting said terminals and comprising two main interrupter portions contained within said chamber, said portions being normally in series electrical connection with one another, one of said portions being in electrical connection with said first stationary terminal, and the other of said portions being electrically connected to the second terminal, the first-mentioned of said interrupter portions comprising separable normally closed switch contact means adapted to be separated to open position under normal load conditions, the other oi said main interrupter portions comprising a fusible member adapted to rupture under overload conditions.

2. An interchangeable interrupter assembly for a circuit interrupter including first and second stationary terminals, said interrupter assembly normally electrically connecting said terminals and comp-rising an elongated insulating tubular member having an arc-extinguishing channel substantially coextensive therewith, two main interrupter portions contained within said channel and normally in series electrical connection with one another, one of said portions being adapted for electrical connection with the first of said stationary terminals and comprising separable normally closed switch contact means adapted to be separated. to open position under normal. load 6. conditions, the; other of. said main interrupter portions being arranged. for electrical connection with said second" terminal and comprising a fusibl'e= member adapted to rupture under overload conditions.

3. An interchangeable interrupter assembly for a circuit interrupter including first and second stationary terminals, said interrupter assembly comprising a tubular member including an arcextingnishing chamber substantially coextensivetherewith, one end. of said tubular member being arranged for releasable pivotable engagement with the first of said stationary terminals and having a conducting member being arranged for latching: engagement with: said second stationary terminal, two maininterrupter portions contained within: said chamber being normally in series: electrical connection with one another biased towards circuit interruption, one of said interrupter portions including a movable arcing contact normally in electrical engagement wit said. conducting member, manually operable restraining means yieldingly holding said movable contact in electrical engagement with said conducting. member, the other or said portions contprising: a fusible member adapted to rupture under overload conditions and arranged for electrical connection with said first stationary terminal'.

i. A circuit interrupter including first and second stationary terminals, an interrupter assembly normally electrically connecting said terminals and comprising in combination an insulating tube pivotally positioned on said first terminal. and: having an arc-extinguishing channel substantially coextensive therewith, two main interrupter portions: located within said channel and normally electrically connected with one another, one of said portions comprising switch means andv the other portion comprising a fusiole means, said switch means comprising a fixed contact adapted: to bereleasably engageable with said second terminal, a movable arcing contact slidable within said channel normally elect -ically engaging said fixed contact, spring means slidably biasing said movable contact towards electrical disengagement, and manually operable re straining means normally holding said contacts inelectrical engagement, said fusible means comprising a fuse link adapted to rupture under overload and electrically connecting said movable contact. with said first terminal, said fuse link being: concurrently urged towards rupture by said spring means.

5. An interchangeable interrupter assembly for a circuit interrupter including first second stationary terminals, said interrupter assembly comprising a tubular member including an arcextinguishing chamber substantially coextensive therewith, one endof said tubular member being arranged for releasable pivotable' engagement with the first of said stationary terminals and having a conducting member positioned proximate to the opposite end thereof, said conducting member being arranged for latching engagement Withsaid second stationary terminal, two main interrupter-portions containedwithin said chamber being normally in series electrical connection with one another and biased towards circuit in terruption, one of said interrupter portions including a movable arcing contact normally in electrical engagement with said conducting member, an insulating follower member" affixed to one end of said movable arcing contact, manually operable; restraining means yieldingly holding ing member being arranged said movable contact in electrical engagement with said conducting member, the other of said portions comprising a fusible member adapted to rupture under overload conditions and arranged for electrical connection with said first stationary terminal.

6. A circuit interrupter including first and second stationary terminals, an interrupter assembly normally electrically connecting said terminals and comprising in combination an insulating tube pivctally positioned on said first terminal and having an arc-extinguishing channel substantially coextensive therewith, two main interrupter portions located within said channel and normally electrically connected with one another, one of said portions comprising switch means and the other portion comprising a fusible means, said switch means comprising a fixed contact adapted to be releasably engageable with said second terminal, a movable arcing contact slidable within. said channel normally electrically engaging said fixed contact, an insulating slidable follower member afllxed to one end of said movable arcing contact, spring means slidably biasing said movable contact towards electrical disengagement, and manually operable restraining means normally holding said contacts in electrical engagement, said fusible means comprising a fuse linl: adapted to rupture under overload and electrically connecting said movable contact with said first terminal, said fuse link being concurrently urged towards rupture by said spring means.

7. An interchangeable interrupter assembly for a. circuit interrupter including first and second stationary terminals, said interrupter assembly comprising a tubular member including an arcextinguishing chamber substantially coextensive therewith, one end of said tubular member being arranged for releasable pivotable engagement with the first of said stationary terminals and having a conducting member positioned proximate to the opposite end thereof, said conductfor latching engage-- ment with said second stationary terminal, a removable protective cap member positioned on and enclosing said tubular member at one end thereof, two main interrupter portions contained within said chamber being normally in series electrical connection with one another and biased towards circuit interruption, one of said interrupter portions including a movable arcing contact normally in electrical engagement with said conducting member, an insulating follower men ber to one end of said movable arcing contact, manually operable restraining means yieldingly holding said movable contact in electrical engagement with said conducting member, the other of said portions comprising a fusible member adapted to rupture under overload conditions and arranged for electrical connection with said first stationary terminal.

8. A circuit interrupter including first and second stationary terminals, an interrupter assembly normally electrically connecting said terminals and comprising in combination an insulating tube pivotally positioned on said first terminal and having an arc-extinguishing channel substantially coextensive therewith, a removable protective cap member positioned on and enclosing said tubular member at one end thereof, two main interrupter portions located within said channel and normally electrically connected with one another, one of said portions comprising switch means and the other portion comprising a fusible means, said switch means comprising a fixed contact adapted to be releasably engageable with said second terminal, a movable arcing contact slidable within said channel normally electrically engaging said fixed contact, an insulating slidable follower member affixed to one end of said movable arcing contact, spring means slidably biasing said movable contact towards electrical disengagement, and normally operable restraining means normally holding said contacts in electrical engagement, said fusible means comprising a fuse link adapted to rupture under overload and electrically connecting said movable contact with said first terminal, said fuse link being concurrently urged. towards rupture by said spring means.

9. A drop-out circuit interrupter construction comprising an upper and a lower stationary terminal, an interrupter assembly having arcextinguishing chamber, said assembly normally electrically connecting said terminals and comprising two main interrupter portions contained within said chamber, said portions being normally in series electrical connection with one another, one of said portions being in electrical connection with said upper stationary terminal, and the other of said portions being electrically connected to said lower terminal, the firstunentioned of said interrupter portions comprising a normally closed switch means adapted to be opened under load conditions, the other of said main interrupter portions comprising a fusible member adapted to rupture under overload conditions, said interrupter assembly adapted to be in latching electrical engagement with said upper terminal, and plural pivot means associated with the interrupter assembly at the lower end for pivotably mounting said tube on said lower terminal to permit downward and outward r cking motion on rupture of said fusible member.

10. A drop-out circuit interrupter construction including first and second stationary term nals, an interrupter assembly normally electrically connecting said terminals and comprising in combination an insulating tube having an arc-extinguishing channel substantially coextensive therewith, two main interrupter portions located within said channel and normally electrically connected with one another, one of said portions comprising switch means and the other portion comprising a fusible means, said switch means comprising a fixed contact adapted to be releasably engageable with said second terminal, a movable arcing contact slidable within said channel normally electrically engaging said contact, spring means slidably biasing said movable contact towards electrical disengagement, and manually operable restraining means normally holding said contacts in electrical engagement, said fusible means comprising a fuse link adapted to rupture under overload and electrically con-- necting said movable contact with said first terminal, said fuse link being concurrently urged to wards rupture by said spring and a plural pivot means associated with the interrup er as sembly at one end thereof for pivotably mounting said tube on said first terminal to permit downward and outward rocking motion on rupture of said fusible member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,441,692 Earle May 18, 1948 2,446,676 Yonkers i Aug. 10, 1948