US2495192A - Snap action circuit closer - Google Patents

Description

Jana N 1950 J. R. WEBB SNAP ACTION CIRCUIT CLOSER 2 Sheets-Sheet 1 Filed Nov. 8, 1945 INVENTOR .fayaph/he/ We Jan. 3% 1950 J. R. WEBB SNAP ACTION CIRCUIT CLOSER 2 Sheets-Sheet 2 9 42 I 44 z I s :1 37 \gil r 3 2/ 5d 5:! 7 d/ 47 as 6/ g a5 ISL"; v49 5 i Q Q Q WITNESSES: 25 INVENTO jaygp/wne E; Wabfi.

Patented Jan. 17, 1950 UNITED STATES PATENT OFFICE SNAP ACTION CIRCUIT CLOSER Josephine. B. Webb, Forest Hills, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationNovember 8, 1945, Serial No. 627,496

14 Claims. 1

This: invention relates to circuit interrupters, and 'more 'particuiarly, to contact structures therefor.

An object of this invention is to provide a circuit interrupter having stationary contact means; cooperating movable contact means and means 'for operating the movable contact means to close the contacts, with means for closing the contacts at a rate of speed greater than the speed of the operating means.

Another object of the "invention is to provide a circuit interrupter having separable contact and operating mechanism therefor with means for 'mcreas'ing the closing speed of the contacts without increasing the s eed of the breaker operating mechanism.

Another object of the invention is to provide a circuit interrupter having, stationary and movable contact means with extensible contact means capable of effecting contact closure at a speed greater than the speed of the movable contact means.

The: novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as toistructure and operation together with additional objects. and advantages thereof will best. be understood from the following detailed description of one embodiment thereof. when read in conjunction with the accompanying drawings, in. which:

Figure l. is elevational. View partly in section, of a 'circuitintcrrupter embodying the principles of the invention and shown in the closed position;

Fig. Z is an enlarged elevational view, in vertical section, taken through one of the interrupti'ng units of Fig. i, the. parts. being shown in the closed circuit position;

Fig. 3 is a fragmentary sectional view of the interrupter shown in Fig. 2, the parts being shown in the circuit open position; Fig. 4 is a sectional 'viewsimilar to Fig. 3 but showing the parts at the instantthe intermediate contact was tripped and before the movable contact has completed its closing movement.

Referring to Fig. l of the drawings, the circuit interrupter comprises, generally, a tank H substantially' filled with an arc extinguishing fluid s'uch, for instance, as oil, insulating bushings I5 and" mounted in the dome shaped cover [,9 of the tank, a'r-c extinguishing units 2| and 23' mounted on the 1111161 ends 0f the bushings 2 l5. and I1, respectively, and a bridging contact member 25. 1

The bridging contact member 25 is .provided with contact members 21 and 29 for cooperating with contact means within the, arc extinguishing units 2| and 23, respectively. The bridging contact member 25 is operated by means of an insulating operating rod 3| which is actuated by suitable operating mechanism of known construction, none being shown.

The construction of arc extinguishing units and the contact structure of the two poles of the breaker are the. same for which reason the mechanism of only one pole is. illustrated in detail and will be described herein.

Referring to Fig. 2, a hollow casting 33, securely counted on the inner-"end of the insulating bushing l5, forms a pressure chamber 35 in which is mounted a pressure contact member 31. The contact member 31 is pivotally mounted on a pin 39 supported in an integral projection 4| of the casting 33. The contact member 3-! is biased in contact closing direction by a spring 42 and is electrically connected by means of a flexible shunt connection 43 to the projection H. A stop 44 is provided to limit clockwisemovement of the contact member 31.

The are extinguishing unit 2| comprises generally a plurality of suitably shaped insulating plates held together by tie rods 45. Certain features of the arc extinguishing unit are described and claimed in patent application Serial No. 465,244, filed November 11, 1942, by Leon R. Ludwig, Benjamin P. Baker and Winthrop M. Leeds, now Patent No. 2,406,469 issued August 27, 1946, and assigned to the assignee of the instant application.

The insulating plates of the arc extinguishing unit form vertical flow passages indicated generally at 41-, which at their upper ends communicate with the pressure chamber 35 and their lower ends with a plurality of arc extinguishing passages 49. Pressure is generated in th'eupper chamber during an opening operation causing oil to flow from the pressure chamber 35 down through the passages 41, through the are extinguishing passages 49 and forces ionized gases out through vents 56. For a complete understanding of the principles of the arc extinguishing unit reference may be had to the aforementioned patent.

Cooperating with the pressure contact 31 is an extensible, telescopic intermediate contact designated generally by the. reference numeral 5|. This intermediate contact, in the closed position of the interrupter, also cooperates with the movable contact 2'! to complete the electrical circuit through the interrupter. The intermediate contact 5| comprises an upper member 53 and a lower member 55. The upper contact member 53 carries a contact 51 which cooperates with a contact 59 on the pressure contact member 31. The lower contact member of the intermediate contact is provided with a contact 6| for cooperating with the movable contact 21.

The two contact members 53 and 55 are generally cylindrical and the upper member 53 has a guide rod 63 formed integral with or otherwise suitably secured to the center portion thereof, which rod telescopes into the lower member 55. The two parts 53 and 55 of the intermediate contact 5| are biased apart by means of a stron compression spring 65 coiled about the guide rod 63, but are normally releasably latched together against the force of the spring 65 by means of a. latch 61 pivoted on a pin 69 supported in a recess formed in the side of the lower member 55. The latch 61 is biased by a spring 13 into latching engagement with an annular groove or notch 15 in the guide rod 63.

In the closed position of the interrupter, the spring 65 is compressed and the two parts 53 and 55 abut against each other as shown in Figure 2, being restrained in this position by the latch 61.

When the operating rod 3| (Fig. l) is released and moved downwardly by accelerating springs (not shown), the bridging contact member is moved to the position shown by dotted lines at 25 in Figure 1. During this downward movement of the bridging contact member, the movable contacts 21, 29 are withdrawn from the arc extinguishing units 2|, 23 to cause separation of the contacts. The contacts 51, 59 are the first to separate and the intermediate contact 5|, biased by a spring 10, moves downwardly with the movable contact 21 until it is arrested by a flange TI on the lower part 55 of the intermediate contact engaging an annular shoulder 19 on the arc extinguishing unit. The contacts 2'|6| now separate and the movable contact continues its downward movement to the full open position indicated at 21' in Figure l. The parts of the contact structure are now in the positions in which they appear in Figure 3.

During the downward movement of the intermediate contact 5| the tail of the latch 61 wiped by a latch operating pawl 8| pivoted on a pin 83 and biased in a clockwise direction against a stop 85 by means of a relatively light spring 81. It will be observed that the pawl 8| is free to rotate in a counterclockwise direction from the position shown against the force of the light biasing spring but its clockwise movement is limited by the stop '85. Consequently, when the tail of the latch 6! engages the pawl 8| during its downward travel, the pawl is rotated counterclockwise thus permitting the latch to pass without unlatching the intermediate contact. The

intermediate contact 5|, therefore, arrives at v the position shown in Figure 3 in its contracted by the fixed rate of movement of the operating mechanism and the movable contact member.

The purpose of such high speed contact closing operation is to prevent prestriking of the are be-, fore the contacts touch. This new and important result is obtained by the provision of the extensible intermediate contact 5| which is released during the closing movement and permitted to expand or elongate at a high rate of speed and close the contacts much quicker than they would be closed by the regular operation of the movable contact structure.

When the operating mechanism (not shown) is energized and caused to move the operating rod upwardly to close the contacts, the moving contact 2'! is drawn upwardly into the are extinguishing unit and engages the intermediate contact 5|. Continuing its upward travel the movable contact 21 carries the intermediate contact therewith and, during the earl part of this movement, the tail of the latch 61 engages the pawl 8| and, since the pawl is prevented from rotating clockwise from its normal position, it cams the latch 6! ma clockwise direction to disengage the latch from the notch 15 in the guide rod 63 thus freeing the upper part 53 of the contact 5| from the lower part 55 thereof. The spring 55 immediately expands and snaps the contact member 53 upwardly at high speed to close the contacts 5|59. The parts are shown in Figure 4 at the instant, after the latch 61 was actuated and the part 53 of the contact 5| has been moved by the spring 65 to close the contacts 5'|59.

Continuing upward or closing movement of the movable contact, following operation of the expansible contact 5|, compresses the spring 65 and causes the two parts 53 and 55 to telescope together in which position they are retained by the latch 51 which is actuated to latching position by the spring 13. The last part of the closlng movement compresses the spring 42 to provide contact pressure.

The member 55 of the intermediate contact is guided in its operation by means of a vertically disposed guide bar 89 of insulating material which is engaged by a slot 9| in the flange 11 of the member 55. In this manner the member 55 is prevented from rotating and the latch 61 is maintained in alignment with the pawl 8|.

By the instant invention, there is provided an expansible telescopic contact which is released during the closing operation of the circuit interrupter to effect high speed closure of the circuit at a speed greater than the speed of the operating member and the moving contact and which is reset and relatched automatically during the latter portion of the closing stroke.

Havin described a preferred embodiment of the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made therein without departing from some of the essential features of the invention.

I claim as my invention:

1. In a circuit interrupter, relatively movable contact means comprising a pressure contact, a movable contact operable to effect closure of said contact means, extensible contact means disposed for longitudinal movement between said pressure contact and said movable contact, means for operating said movable contact to close said contact means, and means releasable during closing movement of said movable contact for effecting high speed elongation of said extensible contact means to effect closure oi said contact means at a. ,speed independent of the closing speed of the movable contact. l

2. In a circuit interrupter, relatively. movable contact means comprising a pressure contact, a

enemies movable-contact operable to efiect. closure oi said CQDUHXZEIHBEES}. extensible contact means longitudinally movable between said pressure contact andrsaid movable; contact, meansfor movingsaid movable contact;to.=-close said contact means, and spring means associated with said extensible contact: and releasable: during. closing: movement of said. movable contact. to effect. high speed elongation of saidextensible contact means to efiect: closure of said. contact means at a speed greater than the.- closing speed of the movable contact.

3.. In a circuit: interrupter,relatively movable contact means comprising a first contact, a movable contact and telescopic contact means disposed: betweensaid' first contact and said movable contact, spring. means for causing high speed elongationot saidtelescopic contact means, means normally preventing; elongation of said telescopic contact means,;operating mechanism. for moving said movable contact. to. effect closing of said contact means, and means operable during a contact closing operation to actuate said preventing. means to permit. said. spring to. elongate said telescopic contact means.

4. In a circuit interrupter, relatively movable contact means comprising a first contact, a movable contact and a telescopiccontact means disposedbetweensaid first contact-and said movable contact, spring means for causing high speed elongation of. said telescopic contact means, means. normally preventing elongation of said telescopic contact means, operating mechanism tor; moving said movable contact to effect. closing of said contact means, and means operable dura con-tact closing. operation to actuate said preventing means to permit said spring to elongate said telescopic contact means, said movable contact near the end of the closing operation effecting resetting and relatching of said telescopic contact means.

5. In a circuit interrupter, separable contact means, a first contact and. a movable contact, means for operating said movable contact to close said contact means, extensible contact means disposed between said first contact and said movable contact and operable by said movable contact, said extensible contact means comprising a pair of telescopic members, spring means biasing said members apart to effect elongation of said extensible contact means, latch means for releasably holding said members together against the force of said spring, and means operable during a closing operation for actuating said latch to permit said spring to separate said members to thereby efiect high-speed elongation of said extensible contact means.

6. In a circuit interrupter, relatively movable contact means comprising a pressure contact, a movable contact and an extensible contact means disposed between said pressure contact and said movable contact, operating mechanism for moving said contact means to open and closed positions, said extensible contact means comprising a pair of telescopic contact members biased apart, means for causing unitary movement of said pair of members in opening direction, said means being operable during a closing operation to cause high speed separation of said pair of members to effect closing of said contact means before said contact means would be closed by said movable contact.

7. In a circuit interrupter, separable contact means and operating mechanism for causing opening and closing of said contact means, said contactimeans comprising; a-firstcontact member, a .reciprocably movable contact, member. and extensible telescopic contact. means for bridging the gap between said first contact and said movable contact, means for causing said telescopic contact to move in opening direction in contracted condition, said .means being operable during; aclosing operation to effect high speed elongation of said telescopic contact means to quickly bridge the gap between said first contact and.- said movable contact.

8., In. a circuit interrupter, a pressure contact, a movable, contact, intermediate con-tact. means disposed between said pressure, contact and said movable contact and operable by said movable contact to close the circuit, operating mechanism for: said movable con-tact, said intermediate contact means comprising a pair of telescopic contaetmembers, means biasing said contact members. apart, means on one of said contact members for releasably holding said contact members to.- .gether, means for engaging and actuating said holding means during a closing operation. to permit-said biasing means to move the other: contact member into circuit closing engagement with said. pressure contact while said one contact member remains incircuit closing engagement with said movable contact.

9. In: a circuit interrupter, relatively movable con-tact means comprising a first contact, a movable contact and intermediate extensible contact means for bridging the gap between, said first contact and said. movable contact, operating mechanism for said contact means, spring means for causing elongation of said extensible contact means to efiect bridging of the gap between said first contact and said movable contact at a speed greater than the speed of the operating mechanism.

10. In a circuit interrupter, comprising relatively movable contact means and operating mechanism therefor, said relatively movable contact means comprising a first contact, a movable contact operable by said operating mechanism to open and close said contact means and intermediate contact means, said intermediate contact means being disposed between said first contact and said movable contact and comprising a pair of relatively movable members each having a contact thereon, a compression spring disposed between said relatively movable members for biasing said members apart to effect elongation of said intermediate contact means, latch means on one of said relatively movable members engageable With the other relatively movable member to releasably couple said members together, and means engageable by said latch during a closing operation for actuating said latch to release said other relatively movable member and permit said spring to effect elongation of said intermediate contact means and closing of said contact means at a speed greater than the speed of the movable contact.

11. In a circuit interrupter, comprising relatively movable contact means and operating mechanism therefor, said relatively movable contact means comprising a first contact, a movable contact operable by said operating mechanism to open and close the circuit and an extensible intermediate contact means, said extensible contact means being disposed in the path of movement of said movable contact between said first contact and said movable contact and comprising a pair of contact members each having a contact thereon, a compression spring disposed between said contact members for biasing said members apart to effect elongation of said intermediate contact means, latch means on one of said contact members engageable with the other contact member to releasably couple said contact member together, and means engageable by said latch during a closing operation for actuating said latch to release said other contact member and permit said spring to effect high-speed elongation of said intermediate contact means and closing of said contact means at a speed greater than the speed of the movable contact, and said movable contact near the end of said closing operation effecting compression of said spring and recoupling of said contact members.

12. In a circuit interrupter, pressure contact means, cooperating movable contact means including an extensible intermediate contact structure, operating mechanism for moving said movable contact means to close said contacts, and sprin means operable during a closing movement of said movable contact means for effecting high-speed elongation of said intermediate contact structure to thereby effect closure of said contact means at a speed independent of the speed of the operating mechanism.

13. In a circuit interrupter, a first contact means, a cooperating movable contact means, intermediate contact means comprising an extensible contact structure disposed between said first contact means and said movable contact means, operating mechanism for efi'ecting closure of said contact means, and spring means operable during a closing operation of said movable contact for causing high-speed elongation of said extensible contact structure to effect closure of said contact means at a speed greater than the speed of the movable contact means.

14. In a circuit interrupter, relatively movable contact means comprising a first contact, a movable contact and an intermediate telescopic contact structure disposed to bridge the gap between said first contact and said movable contact, spring means for causing high-speed elongation'of said telescopic contact structure, means normally preventing elongation of said telescopic contact structure, operating means for moving said movable contact and said telescopic contact structure to effect closing of said contact means, and means operable during a contact closing operation to actuate said preventing means and permit said spring to quickly elongate said intermediate telescopic contact structure to efieot closure of said contact means at a speed greater than the closing speed of said movable contact.

JOSEPHINE R. WEBB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,380,595 Ritz, Jr June '7, 1921 1,620,167 Remde Mar. 8, 1927 2,158,846 Balachowsky May 16, 1939 2,163,559 MacNeill June 20, 1939 2,164,175 Frank June 27, 1939 2,192,772 MacNeill Mar. 5, 1940 2,303,492 Peterson et a1. Dec. 1, 1942 2,392,201 Thumim et a1. Jan. 1, 1946

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