US2757360A - Circuit breaker - Google Patents

Description

W. F. DRIPPS CIRCUIT BREAKER July 3l, 1956 2 Sheets-Sheet 1 Filed June 22, 1955 July 31, 1956 w. F. DRIPPs 2,757,360

CIRCUIT BREAKER Filed June 22, 1955 2 Sheets-Sheet 2 United States Patent O CIRCUIT BREAKER Application June 22, 1955, Serial No. 517,317 14 Claims. (Cl. 340-222) This invention relates to a circuit breaker, and more particularly to an improvement in the type of circuit breaker disclosed in Broverman Patent 2,695,401 issued November 23, 1954, and assigned to the same assignee as the instant patent application.

In the type of circuit breaker disclosed in said Broverman patent signal means is provided which is actuated -to the on position prior to tripping open of the breaker contacts. Also, a manually operable member is provided for actuating the signal means to the oi position, resetting the breaker, and closing the breaker contacts. When the signal means has been actuated to the on position and the breaker contacts have been tripped open, movement of the manually operable member to a counterclockwise and then clockwise position causes actuation of the signal means to the olf position, resetting of the breaker, and closure of the breaker contacts. The parts are so arranged whereby if the signal means is actuated to the on position and the breaker contacts have not yet been tripped open the signal means can be put oif by movement of the manually operable member in a clockwise circuit breaker closed direction. However, such arrangement permits an operator to also put off the signal means when the breaker contacts are in the tripped open position without resetting the breaker and closing the breaker contacts. In said Broverman patent means is provided for preventing an operator from putting off the signal means when the circuit breaker contacts are in the tripped open position without resetting the circuit breaker. Said means comprises cam elements cooperable with the operating shaft of the circuit breaker which lock the operating shaft against clockwise movement for putting off of the signal means when the circuit breaker contacts are tripped open. Said means have served their purpose admirably, however they increase the number of parts of the circuit breaker and the cost of the circuit breaker.

Itis an object of this invention to provide an improvement in the above-mentioned typo f circuit breaker which will attain the function of said Broverman invention at a minimum cost without increasing the number of parts of said circuit breaker.

It is a further object of this invention to provide means internally of the above-mentioned type of circuit breaker which will prevent actuation of the signal means to a non-indicating condition when the breaker has tripped open without resetting the breaker.

My invention comprises making a critical change in the contour of one of the latch or trip elements of the trip assembly of the above-mentioned type of circuit breaker which will ensure at a minimum cost and without any increase in the number of circuit breaker parts against putting off of the signal means when the breaker has tripped open without resetting the breaker.

In a circuit breaker having signal means automatically actuatable to an indicating condition by movement of a latch element from a latching to an unlatching position in'jresponse to predetermined conditions, my invention' comprises means internally of said breaker for retaining said latch element in an unlatching position so long as said breaker is in a tripped open position whereby said signal means cannot be returned to a non-indicating condition when said breaker is in a tripped open position without resetting said breaker.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings,

In the drawings, Fig. l is a broken away perspective diagrammatic View of a preferred form of my invention, the parts thereof being illustrated in the signal light on and circuit breaker tripped open position. Fig. 2 is a broken away side view of my invention when viewed in the direction of arrow 2 of Fig. l. Fig. 3 is another broken away side view of my invention when in the signal light off circuit breaker reset but contacts open position. Fig. 4 is another broken away side View of my invention similar to that of Fig. 3 except the parts thereof are in the signal light off and circuit breaker contacts closed position. Like reference numerals will be used throughout the various figs. to indicate identical parts.

Referring now to the drawings, and more particularly to Fig. l, the circuit breaker comprises lan electrical in-y sulating material base or casing, the major portions of which except for parts 1 and 2 thereof have been broken away in order to illustrate the working parts. Within the electrical insulating base is mounted a U-shaped bimetallic element 3. The bimetallic element 3 is stationary at its righthand end and is free for movement at its lefthand end. Fixed to the righthand end of the righthand leg of the bimetallic element 3 is a stationary breaker Contact 4, and fixed to the righthand end of the lefthand leg of bimetallic element 3 is an electrical terminal 5 for connecting an electrical conductor thereto. The lefthand end of bimetallic element 3 has an electrical insulating material projection 6 thereon which cooperates with -an integral electrical insulating material projection 7 of an electrical insulating material latching or tripping bar 8. Both members 6 and 8 need not necessarily be constructed from electrical insulating material. ever, at least one. of members 6 and 8 should be made from electrical insulating material. The bar 8 is pivotally mounted about its lengthwise axis by virtue of a pair of pivot pins 9 positioned in opposite ends of the bar 8 and rotatably journaled in bearing portions of the electrical insulating material base of the breaker. The bar 3 is continuously biased in a clockwise 'direction about its lengthwise axis by virtue of a spring 10 shown in Fig. 3. Clockwise rotation of the bar 8 is limited by part 2 of the jection 6 will engage the projection 7 and cause the bar 8 to rotate in a counterclockwise direction about its lengthwise axis.

Disposed on the upper surface of the bar 8 is a latching or tripping plate 11 which cooperates with a latch or catch tooth 12. Tooth 12 is formed in the element 13 of electrical insulating material switch arm 19. The movable contact 18 is in electrical contact with an electrical terminal v20 for connecting an electrical conductor thereto, and the lefthand end of switch arm 19 is pivoted about a pin 21 which is journaled in bearing portions of the electrical insulating material base of the circuit breaker. The elements and 16 of the latching or tripping assembly for member 17 are each pivoted to the member 17 at pivot point or pin 22. rThe element 14 is pivoted at one of its ends to the pin 21, and at another ot its ends is pivoted to the element 15 at pivot point or pin 23. At a portion of element 14 disposed intermediate pins 21 and 23 the element 14 is pivoted to one end of element 13 by a pin 24. The other end of element 13 is pivoted to the element 16 at pivot pin 25.

A trip or reset member 17 is pivoted on a pin 38 which is journaled in bearing portions of the circuit breaker electrical insulating material base. interconnecting the switch arm 19 and member 17 is a toggle comprising two levers or links 31 and 32. The lever 31 is connected to the switch arm 19 by a pin 33, and the lever 32 is connected to the member 17 by a pin 34. The two levers or links 31 and 32 are connected to each other at their joint by a pin 35.

Disposed about the member 17 is a manually operable U-shaped member 40. One of the legs of U-shaped inember 40 has been broken away for purposes of clarity, however the lower end of both legs of U-shaped member 4G are pivotally mounted in the circuit breaker electrical insulating material base by virtue of pivot grooves 41 formed in portions 1 of the circuit breaker electrical insulating material base. The bridge portion of the member 40 and the pin 35 ot the toggle linkage 31 and 32 are interconnected by an overcenter spring 42, and the member 4t) is connected to an operating rod 43 by an adjustable linkage 44 and 4'5. r[he operating rod 43 is suitably journaled in the side wall 46 of a transformer tank which encloses a transformer apparatus and the illustrated circuit breaker for protecting said transformer apparatus. The outer end of the operating rod 43 has an operating handle 47 connected thereto. The handle 47 has a pointer 48 thereon which cooperates with a dial 49.

The circuit breaker parts so 'tar described and illustrated are identical to the circuit breaker parts disclosed in said Broverman patent except for the element 14 which has been modiied over the element 6@ o said Broverman patent. ln Fig. 4 the circuit breaker is in its reset position with the circuit breaker contacts 4 and 18 closed. When the circuit breaker is closed the overcenter spring 42 is disposed towards the right ot the center line of the extended toggle linkage 31 and 322. To manually open the breaker contacts 4 and 18 the manually operable member 40 is pivoted in a counterclockwise direction as illustrated in Fig. 3. Counterclockwise movement of the member 40 causes the overcenter spring 42 to move to the left of the center line of the extended linkage 31 and 32 of Fig. 4 and buckle same in the manner illustrated in Fig. 3 to cause opening of the contacts 4 and 18. in the Fig. 4 position of the circuit breaker the overcenter spring 42 will not cause the toggle linkage 31 and 32 to buckle in a righthand direction inasmuch as a collar disposed on the pin 3) acts as a stop or abutment for the extended linkage 31, 32. When the breaker contacts 4 and 18 are manually opened in the manner illustrated in Fig. 3 the member 17 and the latching or tripping assembly 13 to 16 for member 17 are not disturbed but remain in their reset position. That is, when the breaker is manually opened the latching tooth 12 remains latched or catched upon the latching or tripping plate 11 of the latching or tripping bar 8. When a predetermined overload condition occurs in the transformer apparatus to be protected by the circuit breaker, the lefthand end of bimetallic element 3 will be deected upwardly whereby the projection 6 will engage the projection 7 and force the latching bar 8 with its plate 11 to rotate in a counterclockwise direction whereby the tooth 12 of the tripping assembly 13 to 16 is released or disengaged from the plate 11. When tooth 12 is disengaged from plate 11 the resettable trip member 17 is caused to rotate in a clockwise direction about its pivot pin 30 whereby the pivot pin 34 for the upper end of toggle lever 32 moves toward the right of the spring 42. Such movement of the trip member 17 and pivot pin 34 enables the spring 42 to buckle the toggle linkage 31 and 32 and cause opening of the breaker contacts 4 and 18 with a snap action. The circuit breaker parts in their tripped open position are illustrated in Fig. l. T o reclose the breaker contacts 4 and 18 the breaker trip member 17 and tripping assembly 13 to 16 must rst be moved to a reset condition. The breaker is reset by rotating the member in a counterclockwise direction which causes the member 17 to pivot in a counterclockwise direction and reengagement of the tripping assembly 13 to 16 at the tooth 12 with the latching plate 11 in the manner illustrated in Fig. 3. Thereafter the still opened contacts 4 and 18 of the reset circuit breaker can be closed by pivoting the member in a clockwise direction. By resetting of the circuit breaker is meant relatching of the trip assembly and trip member thereof, such as indicated by the condition of parts 13 to 16 and 17 respectively illustrated in Fig. 3, whereby the next movement of the operating member will result in snapping closed of the contacts or switch arm.

The signal means of the circuit breaker is similar to the signal means disclosed in said Broverman patent and comprises a iixed contact 5t) and a horizontally disposed movable contact bar 51 carried by an elongated and generally vertically disposed trip bar 52. The opposite ends of contact bar S1 are guided in slots such as indicated at 53 formed in the opposite sides of a U-shaped support 54 the major portion of which has been broken away for purposes of clarity. The trip bar 52 is vertically guided by a not shown slot formed in the top bridge portion of support 54 in a manner obvious to those skilled in the art. Trip bar 52 is continuously biased in a downward and lefthand direction by a spring 5S and is limited in its lefthaud movement by an adjustable stop 56. The xed contact Si) is insulatingly mounted on the support S4, and in the circuit breaker reset and closed position the lower end of trip bar 52 rests on the latching or tripping plate 11 whereby the movable contact S1 is disengaged from the 'ixed contact 5t). The lower end of the trip bar 52 has a smaller degree of overlap with respect to the plate 11 than the tooth 12 whereby when the bar 8 is rotated in a counterclockwise direction the bar 52 will be released prior to the tooth 12 wherein an indication of overload conditions in the transformer is given before the circuit breaker contacts 4 and 18 are tripped open. When the trip bar 52 is freed from the plate 11 the spring 55 urges the trip bar 52 downwardly to cause the movable contact 51 to engage the xed contact and complete an electrical circuit for a light bulb 57 or the like.

The means for putting ott the signal light 57 comprises a generally horizontally disposed strap 58 connected at its righthand end to the manually `operable member 40 by a lost motion connection comprising a pin S9 and a slot 69. The lefthand end of strap 58 has a generally U-shaped portion 61 integrally formed therewith which embraces opposite sides of the movable contact 51. The strap 58 is urged in a lefthand direction from its extreme righthand position by a spring 62.

Assuming that the signal light contacts 50 and 51 have been tripped to the engaged signal light on position and that the breaker contacts 4 and 18 have been tripped to the open position, the signal light is put off and the circuit breaker is reset and closed by iirst rotating handle 47 in a counterclockwise direction and then in a clockwise direction. When the member 40 is rotated in a counterclockwise direction first the lost motion connection between member 40 and strap 58 is taken up after which strap 58 is moved in a lefthand direction to cause the righthand leg of U-shaped portion 61 to engage and raise contact 51 from the contact 50. When contact 51 is raised by the righthand leg of U-shaped portion 61 the trip bar 52 is simultaneously raised and positioned on the latching plate 11 assuming that the overload condition in the transformer has subsided and that bar 8 has been moved in a clockwise direction whereby it abuts against the stop 2. Such counterclockwise movement of member 40 also resets the tripping assembly 13 to 16 and the trip member 17 of the breaker in the manner illustrated in Fig. 3. After the breaker has been reset the member 40 is rotated in a clockwise direction to extend the toggle 31, 32 and snap close the breaker contacts 4 and 18. Clockwise movement of member 40 from the position illustrated in Fig. 3 to the position illustrated in Fig. 4 first results in taking up of the lost motion connection between member 40 and strap 58 and then movement of strap 58 in a righthand direction whereby the lefthand leg of U-shaped portion 61 engages the movable contact 51. Extreme clockwise movement of the member 40 is illustrated in broken line outline in Fig. 4 and in this position of member 40 the lefthand leg of U-shaped portion 6l will engage the contact 51 and cause lifting thereof as well as the trip bar 52 should trip bar 52 be positioned below the latching plate 11. After extreme clockwise movement of the member 40 to the broken line position illustrated in Fig. 4 the spring 62 will cause a slight retraction of strap 58 and member 40 in a lefthand direction as indicated in the full line position of member 40 in Fig. 4 whereby the contact 51 is spaced from the leg portions of the U-shaped member 61. The purpose of providing the member 40 with a limited amount of clockwise movement such as illustrated in Fig. 4 from the full line position to the broken line position thereof is to permit putting off of the signal light 57 by clockwise circuit breaker closed directional rotation of the handle 47 when the breaker contacts 4 and 18 are still in the closed position and the breaker has not tripped open assuming that the overload condition which caused closure of the contacts t) and S1 has subsided. However, such an arrangement of the circuit breaker and signal mechanism parts means that when the signal light is in the on position and the breaker has tripped open an-operator may put off the signal light by moving the operating handle 4'7 and member 40 in a clockwise direction without irst moving the handle 47 and member 40 in a counterclockwise -direction to ensure that the breaker is also reset when the signal light is put off. In my invention I provide means internally of the circuit breaker to prohibit return of tthe signal means to a non-indicating position when the circuit breaker is in the tripped open position without resetting the circuit breaker.

Said means comprises the lever or cam 14 of the tripping or latching assembly 13 to 16 of the resettable trip member 17. Heretofore the element 14 had a conguration similar to that of element 60 illustrated in said Broverman patent. Said configuration was somewhat similar to that of lever 16 in that it had a rather uniform width along the length thereof. In my invention the elbow portion of the lever 14 has a raised hump or cam edge 14 formed on the outer edge thereof to cooperate with the latch plate 11 in such a manner as to prohibit putting 01T of the signal light when the breaker has tripped open while still leaving the breaker in the tripped open position.

As shown in Fig. 2, when the breaker has tripped open the raised hump or cam edge 14 of lever 14 is so positioned whereby it will prohibit the plate 11 from returning to its extreme clockwise rotated position illustrated in Fig. 3 when the bimetal element 3 has cooled and deected downwardly. That is, the righthand edge of plate 11 is disposed to the left of the righthand end of adjustable stop 56. Accordingly, while the breaker is tripped open through clockwise movement of member 40 will cause raising of contact 51 the lower end of trip bar 52 will not catch on the plate 11 to keep the contacts 50 and 51 disengaged. That is, when the handle 47 is released the trip bar 52 will again fall below plate 11 and cause the signal light to that the breaker is in the tripped open position and that the breaker must be reset and closed.

When the member 40 is pivoted counterclockwise to reset the breaker the raised hump or cam edge 14' of element 14 will assume the position shown in Fig. 3 whereby the plate 1.1 can move to its extreme clockwise position. This is because when the breaker is reset by pivotal movement of trip member 17 in a counterclockwise direction the elements 13, 15, and 16 of the tripping assembly 13 to 16 causes the element 14 to move upwardly and in a righthand direction free and clear of plate 11.

While there has been shown and described a particular embodiment of the invention it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and therefore it is intended by the appended claims to cover all such changes and modications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. In a circuit breaker having signal means automatically actuatable to an indicating condition upon movement of a latch from a latching to an unlatching condition, means for preventing return of said signal means to a non-indicating condition when said circuit breaker is in a tripped open condition without resetting said circuit breaker comprising means internally of said circuit breaker for retaining said latch in its unlatching condition so long as said circuit breaker is in its tripped open condition.

2. In a circuit breaker having signal means automatically actuatable to an indicating condition prior to tripping open of said breaker by movement of a latch from a latching to an unlatching condition, and means for returning said signal means to a non-indicating condition, said breaker having a trip assembly operative when said breaker is tripped open to make said returning means ineffective unless said trip assembly is reset.

3. In a circuit breaker having a pair of trip elements movable from a reset position to a tripped position, said trip elements retained in said reset position and released for movement to said tripped position by movement of a movable latch element from a latching to an unlatching condition, said circuit breaker having means for resetting said trip elements, means for preventing resetting of only one of said trip elements when both of said trip elements have been tripped comprising a portion connected to the other of said trip elements and operative only when said other trip element is in its tripped position to retain said latch element inits unlatching condition.

4. In a circuit breaker having signal means first automatically actuatable from a reset non-indicating condition to a tripped indicating condition and a pair of breaker contacts subsequently automatically actuatable from a reset and closed condition to a tripped open condition, said breaker having resettable trip mechanisms for said signal means and breaker contacts retained reset by a releasable common latch, actuating means for resetting said trip mechanisms, said breaker contacts trip mechanism being effective when tripped to prevent resetting of only said signal means trip mechanism whereby said signal means cannot be returned to a non-indicating condition so long as said breaker contacts remain in a tripped open condition.

5. In a circuit breaker having an indicating mechanism trip assembly and a breaker contacts trip assembly, both of said trip assemblies retained in a reset condition by a common latch movable rst to cause tripping of said indicating mechanism trip assembly and then said breaker contacts trip assembly, and manually actuatable means effective for sole resetting of said indicating mechanism trip assembly or joint resetting of both of said trip asgo on. This informs the operator semblies, said breaker contacts trip assembly having means for making said resetting means ineiiective for said sole resetting when both of said trip assemblies are in their tripped condition.

6. In a circuit breaker having a pair of contacts and signal means automatically actuatable to the on position prior to automatic tripping open of said contacts, automatic actuation of said signal means to the on position and automatic tripping open of said contacts caused by a latch element movable from an operative to an inoperative position in response to predetermined conditions, and a manually actuatable member for resetting said breaker, closing said contacts, and putting ori said signal means, means for preventing putting said signal means O when said contacts are tripped open without resetting said breaker comprising means for retaining said latch element in said inoperative position until said breaker is reset.

7. In a circuit breaker' having a signal contact reset member and a breaker contact reset member cach movable from a reset position to a tripped position in response to unlatching movement of a latch element, said latch element movable to unlatch first said signal contact reset member and then said breaker contact reset member, said breaker Contact reset member having a tripping assembly latched with respect to said latch element to retain said breaker contact reset member in its reset position, means for sole resetting of said signal contact reset member or joint resetting of both of said reset members, said tripping assen bly effective when tripped to retain said latch element in an unlatching condition to make said sole resetting means inciiective.

8. In a circuit breaker having a switch arm movable from a closed position to an open position in response to movement of a latch from a latching position to an unlatching position, said breaker having indicating means movable from a non-indicating position to an indicating position prior to opening of said switch arm in response to said latch movement, a reset member and a spring toggle, a reset member trip assembly connecting said reset member to said latch for retaining said reset member in a reset position when said latch is in said latching position, said trip assembly releasable when said latch is in said unlatching position for tripping of said reset member and tripping open of said switch arm, actuating means having a manually actuatable operating member for resetting said reset member and returning said indicating means to said non-indicating position, said trip assembly having means for preventing return of said indicating means to said non-indicating position by said actuating means unless said reset member is in said reset position or is moved to said reset position.

9. In a circuit breaker having indicating means movable to an indicating condition prior to tripping open of said breaker, and an operating member movable irst in one direction and then in an opposite direction for resetting and `closing respectively said breaker and movable in either of said directions for returning said indicating means to a non-indicating condition, means internally of said breaker for making said operating member when moved in said opposite direction etiective to cause return of said indicating means to said non-indicating condition only if said breaker is closed.

l0. ln a circuit breaker having signal means movable to an indicating condition prior to tripping open of said breaker, and an operating me ber movable in one direction to reset or open said breaker and movable in an opposite direction to close said breaker, said operating member movable in either of said directions to return said signal means to a non-indicating condition, said breaker -having trip means so arranged whereby said operating member when movable in said opposite direction is eective to cause, return of said signal means to said nonindicating condition only if said breaker is not in a tripped yopen condition.

ll. In a circuit breaker having signal means automatically actuatable to an indicating condition prior to automatic tripping open of said breaker, said breaker having means internally thereof for preventing return of said signal means to a non-indicating condition solely by movement of a breaker `operating member in a breaker closed direction only if said breaker has tripped open.

l2. In a circuit breaker having a signal means trip member and a breaker trip member retameo in a trip ready condition by a common latch, said signal means trip member releasable by said latch before release of `said breaker trip member, manually operable means for relatching said trip members and opening and closing said breaker, and means cooperative with said breaker trip member and common latch for preventing relatching of said signal means trip member solely by movement of said manually operable means in a breaker closed direction only if said breaker trip member has been released.

13. ln a circuit breaker having signal means actuatable to an indicating condition prior to tripping open of the breaker, said signal means returnable to a non-indicating condition by movement of a manually operable control means in either a breaker opening direction or a breaker closing opposite direction, said control means also movabie in said breaker opening direction to reset said breaker when it has tripped open, said breaker having a trip assembly rendering movement of said control means in said breaker closing direction etective to cause return of said signal means to said non-indicating condition only it said breaker has not tripped open subsequent to actualtion of said signal means to said indicating condition.

14. ln a circuit breaker having a signal light which automatically goes on prior to automatic tripping open `of the breaker and an operating handle movable in one direction to manually reset said breaker and in an opposite direction to manually close said breaker and put oi said signal liglrt, said handle also movable in said one direction to manually open said breaker, said breaker having a trip assembly cooperative with a latch which permits putting off of said signal light when said breaker has tripped open only by rst moving said handle in said one direction.

No references cited.

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