US3911235A

US3911235A - Flange mounted operator for an enclosed electric circuit breaker

Info

Publication number: US3911235A
Application number: US465214A
Authority: US
Inventors: Donald R Venzke; James L Wiseman; Jr Donald Isaac; James H Leonard
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1974-04-29
Filing date: 1974-04-29
Publication date: 1975-10-07
Anticipated expiration: 1992-10-07
Also published as: GB1512394A; ZA752548B; IT1032774B; CA1021833A

Abstract

A handle of the operator is mounted on an external surface of a flange portion of a wall of an enclosure for a molded case circuit breaker and is drivingly connected to an operating handle of the circuit breaker. Interlock means prevent the operating handle of the circuit breaker from being turned to its ON position with a cover of the enclosure open, and the handle of the operator is normally positioned to mechanically interfere and thereby prevent the opening of the cover when the operating handle of the circuit breaker is in its ON position. The handle of the operator is pivotally mounted for limited movement relative to a drive shaft of the operator and can be locked in a single position to lock the circuit breaker handle in either its ON or OFF position. A true position indicator shows the position of the circuit breaker handle regardless of the position of the operator handle.

Description

Venzke et al.

Oct. 7, 1975 FLANGE MOUNTED OPERATOR FOR AN ENCLOSED ELECTRIC CIRCUIT BREAKER Inventors: Donald R. Venzke; James L.

Wiseman; Donald Isaac, Jr., all of Cedar Rapids, Iowa; James H. Leonard, St. Louis, Mo.

Assignee: Square D Company, Park Ridge, 111.

Filed: Apr. 29, 1974 Appl. No.: 465,214

[52] U.S. Cl. 200/50 A; 200/153 R [51] Int. Cl. HOIH 9/20; HOlH 33/46 [58] Field of Search 200/50 A, 153 R [56] References Cited UNITED STATES PATENTS 2,325,697 8/1943 Millermaster 200/50 A 2,851,548 9/1958 Edmunds 200/50 A 2,882,359 4/1959 Edmunds et al. 200/50 A 3,055,996 9/1962 Beebe et al, 200/50 A 3,059,072 10/1962 Mekelburg et a1 200/50 A Primary Examiner-James R. Scott Attorney, Agent, or Firml-larold J. Rathbun; Ernest S. Kettelson 5 7 ABSTRACT A handle of the operator is mounted on an external surface of a flange portion of a wall of an enclosure for a molded case circuit breaker and is drivingly connected to an operating handle of the circuit breaker. Interlock means prevent the operating handle of the circuit breaker from being turned to its ON position with a cover of the enclosure open, and the handle of the operator is normally positioned to mechanically interfere and thereby prevent the opening of the cover when the operating handle of the circuit breaker is in its ON position. The handle of the operator is pivotally mounted for limited movement relative to a drive shaft of the operator and can be locked in a single position to lock the circuit breaker handle in either its ON or OFF position. A true position indicator shows the position of the circuit breaker handle regardless of the position of the operator handle.

7 Claims, 11 Drawing Figures U.S. Patent Oct. 7,1975 Sheet 1 of 4 3,911,235

M NN m m wl i US. Patent Oct. 7,1975 Sheet 2 of4 3,911,235

FIG.3I W

US. Patent 0a. 7,1975 Sheet 3 of4 3,911,235

US. Patent Oct. 7,1975 Sheet 4 of4 3,911,235

FLANGE MOUNTED OPERATOR FOR AN ENCLOSED ELECTRIC CIRCUIT BREAKER This invention relates generally to operating mechanisms for enclosed circuit breakers, and more particularly to a flange mounted operator including interlock means comprising an external operating handle which is normally positioned to mechanically interfere and thereby prevent the opening of the cover of the enclosure when the circuit breaker is ON and an additional interlock which prevents turning the circuit breaker ON when the cover is open.

In such operating mechanisms, it is desirable to be able to disengage the handle of the operator from the operating mechanism thereby to provide access to the circuit breaker within the enclosure when the circuit breaker is in the ON position. Further, it is desirable that there is an indication of the true position of the circuit breaker handle regardless of the position of the handle of the operating mechanism.

Accordingly, it is an object of the present invention to provide an improved external operator for an enclosed circuit breaker which includes an interlock for preventing opening of a cover of the enclosure when the circuit breaker is ON and for preventing turning the circuit breaker ON when the cover of the enclosure is open.

It is a further object to provide an improved circuit breaker operator having a handle movable to a fixed position and lockable in such position to maintain a settable operating handle of the circuit breaker in either its ON or OFF position against manual movement thereof.

Another object is to provide an improved means for indicating the position of a handle of an enclosed circuit breaker regardless of the position of an external handle of an operator for the circuit breaker.

Other objects and advantages of the invention will appear when the following specification is considered together with the accompanying drawings, in which:

FIG. 1 is a partially exploded perspective view of a flange mounted operator in accordance with this invention for a molded-case electric circuit breaker contained within an enclosure, portions of the enclosure being removed for clarity;

FIG. 2 is a front view of a handle assembly of the operator shown in FIG. 1, the handle being in the OFF position and a locking hasp being in an operative position; FIG. 3 is a side view of the handle assembly of FIG.

FIG. 4 is an enlarged fragmentary sectional view taken along the line 44 of FIG. 3;

FIG. 5 is a fragmentary front view of the handle operator and enclosure with the handle of the operator positioned in interfering relation with a cover of the enclosure;

FIG. 6 is an enlarged fragmentary sectional view taken along the line 66 of FIG. 3 showing rotated positions of a key of the operating handle;

FIG. 7 is a fragmentary view, partially in section, of a defeater mechanism shown in broken lines in FIG. 3;

FIG. 8 is a side view of the handle assembly of the operator with a handle interlock in its latched position;

FIG. 9 is a view similar to FIG. 8 except that the handle interlock is in its unlatched position;

FIG. 10 is a top view of the handle assembly showing the interlock mechansim; and

FIG. 11 is a fragmentary view showing a latch plate of the interlock mechanism in engagement with a handle latch member of the interlock mechanism.

Referring principally to FIG. 1, an operator 10 constructed in accordance with this invention is shown as associated with a molded case circuit breaker 12 within an enclosure or box 14. The circuit breaker 12, for example, may be one such as disclosed in US. Pat. No. 3,345,591 of James H. Leonard et al. which issued Oct. 3, 1967.

Such a circuit breaker includes a settable operating handle which is rockable between ON and OFF positions. Snap-action lost motion means, including overcenter springs, connect the settable operating handle to a movable contact carrier so that when the settable handle is moved manually a predetermined distance partway toward either ON or OFF positions, selectively, the movable contacts are moved with a snap motion to the final position towards which the handle is being moved or rocked.

The settable operating handle can be rocked a considerable distance in either selected direction before the over-center springs of the circuit breaker become effective to drive the movable contact carrier. Until the handle reaches the position at which the over-center springs drive the carrier, it is biased by the springs to return to the position opposite to that in which it is being moved manually. When the springs do operate, the settable handle is moved to, and yieldably held in, the final position toward which it was being moved manually.

The circuit breaker 12 is mounted on a back wall 16 of the enclosure 14. The enclosure 14 has a side wall 17 which is provided with a flange 18 forming a marginal front wall, and has the usual other side walls (not shown). An open front of the enclosure 14 is closed by a cover 15 hinged along a front edge of a side wall (not shown) opposite the side wall 17.

The operator 10 includes a linkage assembly 19 mounted on a front surface of the circuit breaker 12 in driving relation with a settable operating handle 20 of the circuit breaker 12. The assembly 19 is held in place by screws 25, which also serve to hold the circuit breaker 12 on the back wall 16, and comprises a four bar linkage with the handle 20 passing through an opening 24 in an operating link 21 at approximately the mid-point thereof. The linkage assembly 19 includes a fixed link or base plate 22 held in place on the front surface of the circuit breaker 12 by the mounting screws 25, the operating link 21 being pivotably connected adjacent one of its ends to the base plate 22 by a fixed pivot pin 23 received in a slot 21a in the link 21 and adjacent the other of its ends being pivotally connected to one end portion of a connecting link 26 by a pin 27. Pivotably connected to the link 26 at its other end portion is an end portion of a driving link 28. Connected to the linkage assembly 19 is a drive shaft 29 which is secured in and preferably passes through a complementary opening in the link 28 adjacent the other end portion thereof. The drive shaft 29, which most conveniently may be of square cross-section throughout most of its length, is operatively connected at its outer'end portion to a handle assembly 31 of the operator l0.

Pivotally mounted guard members 30 are provided in the opening 24 in the link 21 to smoothly engage the operating handle 20. An enlarged head portion 32 of the pin 27 extends rearwardly of the assembly 19 and has a circumferential groove 33 slideably engaging a longitudinal edge 22a of the base plate 22 for maintaining the

links

21, 26, and 28 of the assembly 19 in mutual alignment during operation of the handle assembly 10.

An electric interlock in the form of a snap switch 34 is mounted on the mounting plate 22 for a purpose to be described.

The handle assembly 31 is mounted on the front surface of the flange 18 of the enclosure 14 and comprises an operating handle 36 and a base 37. The base 37 has indicia 38a of an indicating means 38 (FIG. 2) printed or formed thereon at an upper portion thereof (as viewed in FIG. 1), and a locking hasp 39 is pivotally mounted at a lower portion of the base 37 by having end portions of the hasp 39 trapped in a recess between the base 37 and the surface of the flange 18 defined by a transverse slot 37a in the base.

As shown best in FIG. 3, an outer end portion 29a of the drive shaft 29 is cylindrical and is received in a complementary socket formed in an inner end portion of a cylindrical shaft 40 of the handle assembly 31 and is secured to the shaft 40 by a suitable pin 40a. The shaft 40 is rotatably mounted within the upper portion (as viewed in FIG. 1) of the base 37 and a retaining ring 41 suitably received in a groove in the shaft 40 prevents outward or forward movement of the shaft 40 with respect to the base 37.

The operating handle 36 of the handle assembly 31 is mounted for limited pivotable movement on an enlarged outer end portion 40b of the shaft 40 as will be described, the outer end portion 40b of the shaft 40 being received in a complementary socket in the handle 36. The handle 36 is retained on the shaft 40 by a spring loaded key 43 mounted in the handle 36.

The defeater mechanism 42 of the operator is enclosed by the handle 36 and includes the spring loaded key 43 (FIG. 6 and 7) slidably received in a recess in the handle 36 and having an end portion normally received in a slot 40c in the shaft 40 and held therein by a compression spring 47. The key 43 thus normally rigidly couples the handle 36 to the rotatable shaft 40. Because the shaft 40 is rigidly coupled to the drive shaft 29 by the pin 40a, the handle 36 directly transmits torque applied to the handle 36 through the

shafts

40 and 29 to the linkage assembly 19 thereby to operate the settable handle 20 of the circuit breaker 12.

In the OFF position of the handle assembly 31, the settable handle 20 of the circuit breaker 12 is in the OFF position, and the handle 36 is aligned with and overlies the base 37 as shown in FIG. 2 and 3. To move the circuit breaker 12 to its ON position, the handle 36 is moved to a position which is diagonal with respect to the base 37 and lies in interfering relation across the face of the cover as shown in FIG. 5. Thus, when the settable handle of the circuit breaker 12 is in the ON position and the cover 15 is closed the handle 36 prevents opening of the cover.

It is sometimes desirable for certain maintenance purposes to be able to open the cover 15 when the circuit breaker is ON. For this purpose the defeater mechanism 42 including the key 43 is provided. An opening 36a extending inwardly from the front surface of the handle 36 provides access to the key 43 and is aligned with a slot 43a in the key 43 as best shown in FIG. 2. By means of a screwdriver or similar tool engaging the slot 43a as shown in FIG. 7, the key 43 may be disengaged from the slot 400 to permit limited movement of the key along a circumferential groove 44 in the shaft 40 to the position shown in phantom in FIG. 6 to permit movement of the handle 36 from the ON position of FIG. 5 to the OFF position of FIG. 2 without turning the

shafts

29 and 40, thus leaving the circuit breaker handle 20 in the ON position. The handle 36 now overlies the base 37 even though the settable handle 20 is in the ON position. The handle 36 must be physically retained in that position either manually or by the locking hasp 39 when the circuit breaker 12 is ON because the handle 36 is normally biased by a handle return spring 46 (FIG. 4) toward the position on the shaft 40 where the key 43 would be forced into the slot 400 by the compression spring 47. The handle return spring 46 curves around the shaft 40 as seen in FIG. 4 and is held at one end on a pin 46a secured to the shaft 40 and at the other end on an integral pin 46b formed on the underside of the handle 36.

The locking hasp 39 may be rotated upwardly to overlie the operator handle 36 at a lower end portion thereof to maintain the handle 36 in the OFF position. One or more padlocks (not shown) may be secured to the locking hasp 39 to prevent rotation thereof and lock the handle 36 in the OFF position. Due to the defeater mechanism 42, the circuit breaker handle 20 may be in the ON or OFF position when the operator handle 36 is locked in the OFF position. Although the circuit breaker handle 20 may be locked externally in the ON position, the contacts (not shown) of the breaker 12 will open if the breaker is tripped by a pushto-trip button or an electrical fault and the handle 20 will be moved to a TRIP position by the internal structural mechanism of the breaker.

In addition to the indicia 38a, the indicating means 38 includes a pointer 48 rigidly secured to the shaft 40 so as to indicate the position of the handle 20. Since the pointer 48 is rigidly secured to the shaft 40, rotation of the handle 36 with respect to the shaft 40 does not affect, the position of the pointer 48 and the true position of the handle 20 is always shown by the position of the pointer 48.

A lost motion connection is provided between the operating link 21 and the base plate 22 at the pivot pin 23. As mentioned, the pin 23 is received in the slot 21a in the link 21. A torsion spring 51 having a coiled end portion 51a and a yieldable end portion 51b is secured to a down-turned ear 21b of the link 21 at the coiled end portion 51a. The yieldable end portion 51b engages the pin 23 at the open side of the slot 21a to limit the load applied to the circuit breaker handle 20. If excessive force is applied to the operator handle 36, the spring 51 yields and allows the link 21 to pivot about the circuit breaker handle 20 until the pin 27 strikes a stop at the lower end of the edge 22a.

Normally the cover of the enclosure 14 cannot be opened when the circuit breaker 12 is ON because the handle 36 is positioned across the face of the cover 15 (see FIG. 5) when the circuit breaker 12 is ON. However, it is desirable to have additional interlock means 7 to prevent moving the handle 36 from the OFF position 18 having tapped holes 54 which are aligned with openings in the operator base 37 and corresponding openings in the flange 18,- the aligned openings receiving screws 56 which secure the handle latch bracket 52 to the inner side of the flange 18 and the base 37 to the outer side of the flange 18. The bracket 52 has a bight portion 53 and jaws or jaw portions 57 which extend outwardly and forwardly from opposite sides of the bight portion 53 to lap the shaft 29. A rounded latch plate 58 having a square opening at its center is slideably mounted on the shaft 29. The plate 58 is retained between upper and lower portions of the jaws 57. A generally U-shaped latching member 59 engages a shoulder defined by a radially enlarged portion 58a (FIG. 11) of the plate 58 to prevent rotation of the plate 58 and the shaft 29. The generally U-shaped latching member 59 has a bight portion 59b (FIG. I0) and latch-type leg portions 59a which overlap the jaw portions 57 and are suitably attached to the bracket 52 at an inner end portion of the jaws 57 by a pin 62 as shown in FIGS. 8l0. An L-shaped actuating lever 60 has a base portion attached to the bight portion 59b of the latching member 59 by screws 61 and a leg portion extending above the frontal plane of the enclosure 14 when the cover 15 is open. The latching member 59 is biased by a torsion spring 63 (FIG. which wraps around the pin 62 and has one end portion engaging an upper wall of the latch bracket 52 and a second end portion engaging the bight portion 59b of the latching member 59. The latching member 59 is biased to engage the latch plate 58 when the cover is open to prevent movement of the operator handle 36 and the circuit breaker handle 20 to the ON position. When the lever 60 is moved downwardly, as by the closing of the cover of the enclosure 14, the latching member 59 is disengaged from the latch plate 58 and moved to the position shown in FIG. 9, permitting rotation of the shaft 29 and the operator handle 36 and movement of the circuit breaker handle to the ON position.

An electrical interlock which permits switching of control circuits in sequence with the circuit breaker 12 includes the snap switch 34 (FIG. 1) which is secured to the linkage mounting plate 22 by mounting screws 64 and is activated by a slider 65 mounted on a post 22a associated with the plate 22 and is biased toward the link 21 by a spring 66. The slider 65 is a generally U-shaped member having upturned

leg portions

68 and 69 and a ramp 67 in the bight portion thereof. The leg portion 68 has an opening therein which receives the post 22a, the spring 66 having ends which abut the leg portion 68 at one end and the edges at the base of the post 22a at the other end. Slots 69a on opposite sides of the leg portion 69 receive edges of the plate 22 to maintain the movement of the slider 65 in a plane parallel to the plate 22. The ramp 67 on the slider 65 operates the snap switch 34, which is seated on the plate 22 between

leg portions

68 and 69, through the movement of the circuit breaker handle 20. When the operator 10 moves the circuit breaker handle toward the ON position, the link 21 pushes the leg portion 69 on theslider 65 to operate the snap switch 34 before the circuit breaker 12 is turned ON. When the operating link 21 moves the handle 20 toward the OFF position, the spring 66 engages the leg portion 68 to bias the slider 65 toward the link 21. The body of the switch 34 restricts movement of the slider 65 by engagement with the leg portion 68. The slider 65 operates the snap switch 34 before the circuit breaker 12 is turned OFF to turn off control circuit devices before the breaker contacts open, thus permitting the breaker to open under no-load conditions.

We claim:

1. An enclosed circuit breaker and external operating mechanism therefor comprising an enclosure having a rear wall opposite a frontaccess opening, a hinged cover for the access opening closeable against a front wall flange defining an edge of the access opening, a molded case circuit breaker mounted on the rear wall and having a front-facing settable operating handle pivotable-about an axis between ON and OFF positions, a driving member passing through an opening in the flange and extending inwardly of the enclosure toward the circuit breaker, connecting means associated with the inner end portion of the driving member for movement in a first plane between first and second positions upon rotation of said driving member in opposite directions and connected to the handle of the circuit breaker to move said handle in a plane transverse to said first plane between said ON position when said connecting member is moved to said first position and said OFF position when said connecting member is moved to said second position, an exterior operating handle mounted on the driving member for rotating the operating member and being pivotable between ON and OFF positions corresponding respectively to the ON and OFF positions of the circuit breaker handle, and releasable means interconnecting the pivotally mounted handle and the driving member, said releasable means being movable between an engaged and disengaged position, whereby in said disengaged position the handle may be freely rotated relative to the driving member between said ON and OFF positions, and in said engaged position said handle and said driving member are connected to rotate together between said ON and OFF positions.

2. An enclosed circuit breaker and external operating mechanism as claimed in claim 1 wherein the releasable means comprises a key slot in the driving member, an arcuate peripheral groove coextensive with the key slot, a spring-biased key in the external handle received in the key slot, and a handle return spring peripherally mounted on the driving member which biases the key of the external handle toward the key slot of the driving member.

3. An enclosed circuit breaker and external operating assembly as claimed in claim 1 wherein the external handle assembly has indicating means thereon for indi cating the position of the operating handle of the enclosed circuit breaker.

4. An enclosed circuit breaker and external operating mechanism as claimed in claim 2 wherein the indicating means includes a scale mounted on the handle assembly and a pointer rigidly mounted on the driving member, said pointer being rigidly mounted on the driving member to indicate the true position of the operating handle of the circuit breaker.

5. An enclosed circuit breaker and external operating mechanism as claimed in claim 1 wherein the external handle has indicating means for indicating the true position of the operating handle of the circuit breaker, said indicating means including a scale on the external handle and a pointer rigidly mounted on the driving member of the handle assembly, said pointer so mounted that disengagement of the external handle from the keyed slot for limited pivotal movement along the peripheral groove of the driving member will not cause corresponding movement of the pointer,

whereby the true position of the operating handle of the enclosed circuit breaker is indicated regardless of the position of the external handle.

6. An enclosed circuit breaker and external operating mechanism as claimed in claim 1 wherein the operating mechanism has interlock means for preventing operation of the external handle when the cover is open.

7. An enclosed circuit breaker and external operating mechanism as claimed in claim 6 wherein the interlock means comprises a latch assembly secured on an inner surface of the enclosure opposite the external handle, the latch assembly being operatively connected to the driving member of the handle operating mechanism and including a latch bracket suitably secured to the underside of the front flange of the enclosure, the latch bracket having upper jaw-like portions, the jaw portions of the latch bracket retaining a latch plate, the latch plate having an opening therein which receives the driving member of the operating mechanism and operates in cooperation therewith, a latching member suitably secured to the jaw portion of the latch bracket, the latching member biased to engage the latch plate and thereby prevent movement of the driving member of the operator mechanism, an actuating lever rigidly secured to the latching member and extending above the frontal plane of the enclosure, the latching member being disengageable from the latch plate when the ac tuating lever is engaged by the cover and moved toward the frontal plane of the enclosure thereby.

Claims

1. An enclosed circuit breaker and external operating mechanism therefor comprising an enclosure having a rear wall opposite a front access opening, a hinged cover for the access opening closeable against a front wall flange defining an edge of the access opening, a molded case circuit breaker mounted on the rear wall and having a front-facing settable operating handle pivotable about an axis between ON and OFF positions, a driving member passing through an opening in the flange and extending inwardly of the enclosure toward the circuit breaker, connecting means associated with the inner end portion of the driving member for movement in a first plane between first and second positions upon rotation of said driVing member in opposite directions and connected to the handle of the circuit breaker to move said handle in a plane transverse to said first plane between said ON position when said connecting member is moved to said first position and said OFF position when said connecting member is moved to said second position, an exterior operating handle mounted on the driving member for rotating the operating member and being pivotable between ON and OFF positions corresponding respectively to the ON and OFF positions of the circuit breaker handle, and releasable means interconnecting the pivotally mounted handle and the driving member, said releasable means being movable between an engaged and disengaged position, whereby in said disengaged position the handle may be freely rotated relative to the driving member between said ON and OFF positions, and in said engaged position said handle and said driving member are connected to rotate together between said ON and OFF positions.

3. An enclosed circuit breaker and external operating assembly as claimed in claim 1 wherein the external handle assembly has indicating means thereon for indicating the position of the operating handle of the enclosed circuit breaker.

5. An enclosed circuit breaker and external operating mechanism as claimed in claim 1 wherein the external handle has indicating means for indicating the true position of the operating handle of the circuit breaker, said indicating means including a scale on the external handle and a pointer rigidly mounted on the driving member of the handle assembly, said pointer so mounted that disengagement of the external handle from the keyed slot for limited pivotal movement along the peripheral groove of the driving member will not cause corresponding movement of the pointer, whereby the true position of the operating handle of the enclosed circuit breaker is indicated regardless of the position of the external handle.

7. An enclosed circuit breaker and external operating mechanism as claimed in claim 6 wherein the interlock means comprises a latch assembly secured on an inner surface of the enclosure opposite the external handle, the latch assembly being operatively connected to the driving member of the handle operating mechanism and including a latch bracket suitably secured to the underside of the front flange of the enclosure, the latch bracket having upper jaw-like portions, the jaw portions of the latch bracket retaining a latch plate, the latch plate having an opening therein which receives the driving member of the operating mechanism and operates in cooperation therewith, a latching member suitably secured to the jaw portion of the latch bracket, the latching member biased to engage the latch plate and thereby prevent movement of the driving member of the operator mechanism, an actuating lever rigidly secured to the latching member and extending above the frontal plane of the enclosure, the latching member being disengageable from the latch plate wHen the actuating lever is engaged by the cover and moved toward the frontal plane of the enclosure thereby.