US2996589A

US2996589A - Pivoted bimetal

Info

Publication number: US2996589A
Application number: US807885A
Authority: US
Inventors: Felix E Myers
Original assignee: ITE Circuit Breaker Co
Current assignee: ITE Circuit Breaker Co
Priority date: 1959-04-21
Filing date: 1959-04-21
Publication date: 1961-08-15
Anticipated expiration: 1978-08-15

Description

3 Sheets-Sheet 1 Aug. 15, 1961 F. E. MYERS PIVOTED BIMETAL Filed April 21, 1959 l? l u' Aug. 15, 1961 F. E. MYERS PIvoTED BIMETAL 5 Sheets-Sheet 2 Filed April 2l, 1959 INVENTOR. FEL/X /WVEJ' j Qlq;

#frag/WW Aug. l5, 1961 F. E. MYERS 2,996,589 PrvoTED BIMETAL Filed April 2l, 1959 3 Sheets-Sheet 5 f lj'jjl I iii-I u] C: A I 'j w1 H n QQ u w il I j il) I *l INVENTOR.

United States Patent 2,996,589 PIV O'IlED BIMETAL Felix E. Myers, Haddon Heights, NJ., assigner to I-T-E `Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Apr. 21, '1959, Ser. No. 807,885 16 Claims. (Cl. Z110-116) The instant invention relates to circuit breakers in general and more particularly to an improved construction of a multi-phase circuit breaker formed by stacking a plurality of single phase circuit breakers, each having its own operating mechanism, side by side and mechanically interconnecting their automatic trip units so that upon the automatic tripping of one of the phases the remaining phases will also trip.

Briefly, each single phase circuit breaker of the type required comprises an operating mechanism for operating the circuit breaker cooperating contacts into and out of engagement with the operating mechanism including a latchable means which, `when latched permits the cooperating contacts to be brought into engagement. The latch for the latchable means is mounted to the free end of a current responsive control member which in this case comprises a bimetallic element. A trip lever movable by the latchable means is upon movement thereof engageable with the control member and when so engaged unlatches the latch for the latchable means. The trip levers of all of the circuit breakers in the stack are tied together for simultaneous movement thereof. When the latchable means of one circuit breaker is unlatched because of an overload condition existing at that circuit breaker its latchable means Will impart a movement to its associated trip lever with this movement in turn being imparted to the trip levers of the remaining circuit breakers to bring about the opening of these remaining circuit breakers.

Prior art circuit breakers of this general type are exemplied by the circuit breaker illustrated in the P. M. Christensen Patent No. 2,824,191. This patent discloses three single phase circuit breakers stacked side by side with the interconnection of the circuit breaker automatic trip units being accomplished by tongue and groove joints with the tongue and grooves being formed integral with the circuit breaker trip levers. With this arrangement, the trip levers of each of the circuit breakers is of a different construction so that in eifect it is necessary to provide three different type circuit breakers for each stack of three breakers.

In the device of the instant invention all of the single phase circuit breakers is of identical construction with the trip levers being provided with an opening to receive a common element which extends between all of the circuit breakers. This common element comprises a simple rod-like member of uniform cross-section whose length is determined by the number of circuit breakers in the stack.

In the device of the instant invention a common pivot is utilized for both the control member and the trip lever. From a mechanical standpoint, this is the most advantageous arrangement of the two elements. Further, this arrangement has been found to be more convenient for assembling than the prior art arrangements which require separate pivot points for the control member and the trip lever.

In stacked circuit breaker arrangements of the type in question the operating mechanism of the overloaded phase must supply not only the energy required to move the contacts of this phase out of engagement but must also supply the forces for unlatching the latches of the remaining phases. Because of this there must be a low frictional engagement between the latchable means and Y 2,996,589 Patented Aug. 15, 1961 the trip lever. In the instant invention this is accomplished by providing the latchable means with a roller which engages a trip lever so that there is rolling engagement between the two elements rather than the rubbing engagement which is found in the prior art devices.

Accordingly, a primary object of the instant invention is to provide a novel construction for a single phase circuit breaker which is adapted to be stacked with other single phase circuit breakers with all of the circuit breakers having their automatic trip means tied together so that the automatic operation of one circuit breaker Will trip the other circuit breakers.

Another object of the instant invention is to provide a stack of single phase circuit breakers Whose automatic trip means are mechanically tied together with the external construction for all of the circuit breakers being identical.

Still another object is to provide a circuit breaker construction wherein a common pivot is utilized for the control element and the trip lever.

A further object is to provide a stack of circuit breakers whose trip levers are interconnected by means of a common element which is of uniform cross-section throughout the length thereof.

Still another object is to provide a circuit breaker construction wherein there is a low frictional engagement between the latchable means and the trip lever.

'Ihese as well as other objects of the instant invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is an end vliew of a stack of three single phase circuit breakers looking toward the load terminals thereof.

FIGURE 2 is a side elevation of one of the circuit breakers of FIGURE l with the cover removed and the mechanism thereof in the reset position.

FIGURES 3 and 4 are similar to FIGURE 2 with the circuit breaker mechanism being in the on and tripped positions, respectively.

FIGURE 5 is a plan view of the stack of circuit breakers illustrated in FIGURE l.

FIGURE 6 is an exploded View of the elements comprising the circuit breaker automatic tripping means.

Now referring `to the figures, the stack of circuit breaker 10 illustrated in FIGURE l comprises three single phase circuit breakers 11, 12, 13 mounted side by side. Each of the circuit breakers 11-13 comprise identical single phase units which are of the type generally utilized for home and light industrial applications and having a rating in the range of from 15 to 60 amperes.

The manual operating handles 14 of all three circuit breakers 11-13 are tied together by an elongated cap 15 and pin 16 so that manual operation of all three circuit breakers 11-13 occurs simultaneously. As will be hereinafter described in detail, common tie bar 17 mechanically interconnects the automatic trip units of all circuit breakers 11-13 for simultaneous tripping upon the occurrence of an overload condition in any one of the circuit breakers 11-13.

Since each of the circuit breakers 11-13 is of an identical construction, both internal and external, only circuit breaker 11 will be described in detail, it being understood that circuit breakers 12 and 13 have the same construction. Circuit breaker 11 comprises a base 18 of molded insulating material having an open side 19 capped by removable cover 20, which is also constructed of molded insulating material, with cover Ztl being secured to base 18 by rivets 21 which pass through all three circuit breakers 11-13. Stationary contact 22 is mounted to extension 23 of female stab type line terminal 24 which is disposed in a suitably shaped base recess. The lower end 25 of line terminal Z4 is accessible through a suitable slot formed by the cooperation of cover 20 and base 18.

Cooperating with stationary contact 22 is movable Contact 26 which is mounted to the lower end of movable contact arm 27 whose upper end abuts a suitable pivot forming formation of manual operating member 28. Parallel plate slotted arc extinguishing means 99 is operatively positioned to receive and extinguish electric current arcs drawn between

contacts

22, 26. Manual operating member 28 is pivoted about protrnsions 29 thereof which is entered into suitable recesses (not shown) of cover 20 and base 18.

Operating mechanism 30, for bringing about the engagement and disengagement of cooperating

contacts

22, 26 comprises latchable cradle 31 which is pivoted at o-ne end thereof at base protrusion 32. One end of cooperating spring 33 is tied to cradle 31 at a point intermediate the ends thereof while the other end of spring 33 is tied to contact arm 27. Operating spring 33 is always tensioned thereby urging contact arm 27 upward into engagement with its pivot or manual operating member 28. The other end of cradle 31 comprises latch tip 34 which is engageable by latch 35 secured to control member 36 by rivet 35.

Control member 36 comprises an elongated bimetallic element which is mounted near the upper end thereof to pivot pin 37. Magnet 38 is secured to control member 36 near the lower end thereof by rivet 35. Bifurcated member 39 is secured to control member 36 below magnet 38. Conducting braids 40a and 40h extend Ifrom legs 41a, 41b, respectively of bifurcated member 39 to contact arm 27 and provide dual electrical paths between contact arm 27 and bimetallic element 36.

Control member 36 is biased in a clockwise direction by pivot spring 40 which is disposed in recess of base 18 with one end of spring 40 abutting wall 42 of recess 40 and the other end of spring 40 abutting the portion of control member 36 positioned above pivot 37. The normal position of control member 36 is set by adjusting screw 43 which extends through an opening in base 18 and is received by nut 44 disposed in a suitable recess in base 18. The end of screw 43 opposite head 45 thereof abuts one leg of tensioning member 46 thereby forcing tensioning member 46 against control member 36 to bodily move control member 36 about pivot 3'7.

When magnet 38 is energized suiciently by current owing through control member 36 magnet 38 is attracted to armature 47 whose legs 48, 49 are disposed in oversized base recesses 50, 51, respectively, and whose legs 52, 53 are disposed in similar oversized recesses (not shown) of cover 20. Leaf spring 54 disposed within a suitable recess of base 18 with the offset lower end thereof abutting armature 47, urges armature 47 against the left-most walls forming recesses 50i, 51. The resilient mounting of armature 47 provides means for cushioning the shock impact which accompanies the engagement of magnet 38 with armature 47 caused either by the deflection of control member 36 due to heating or else by the bodily movement of control member 36 about pivot 37 due to the energization of magnet 38.

Insulating sheet 55 is interposed between spring 54 and flexible braid 57 which electrically connects load terminal member 56 to control member 36 with sheet member 55 protecting braid 57 from damage which would result if braid 57 were to rub against the sharp edges of spring 54. Terminal member 56 is entered into Wire connector 58 which is disposed within suitable recesses of base 18 and cover 20.

Thus, the current carrying path through circuit breaker 11, beginning at the load side thereof, comprises terminal 56, braid 57 to the upper end of bimetallic control member 36, through control member 36 and bifurcated member 39, through the parallel pat-hs formed by braids 40a,

4 40b to contact arm 27, and through engaged cooperating

contacts

26, 22 to line terminal 24.

Roller 59, pivoted at 60 to cradle 31, engages trip lever 61 upon operation of cradle 31 between its latched position (FIGURES 2 and 3) and its tripped position (FIG- URE 4). Engagement of trip lever 61 by roller 59 forces trip lever 61 counterclockwise about pivot 37 into engagement with control 36 thereby causing member 36 to pivot counterclockwise about pivot 37 against the force of spring 40.

When cradle 31 moves from` the circuit breaker On position of FIGURE 3 to the tripped position of FIG- URE 4 the end 65 of kicker 66 which is pivoted at 67 to cradle 31 now engages contact arm 27 with a hammerlike blow thereby assuring separation of

contacts

22, 26 even though there is a tendency for these contacts to weld. The path of kicker tip 65 is dictated by the movement of pivot point 67 and the fact that the other end 68 of kicker 66 is disposed within base recess 69. Circuit breaker 11 is operated from the tripped position of FIGURE 4 to the reset position of FIGURE 2 by the operation of handle 14 to the right. This causes manual operating member 28 to pivot clockwise about its pivot 29 and the lower extension thereof engages p-in 70 which protrudes from cradle 31. Cradle 31 moves counterclockwise about its pivot 32 and in so moving roller 59 engages tip lever 61 which in turn moves control member 36 counterclockwise carrying latch 3S to the right thereby permitting latch tip 34 to pass latch 35. When latch tip 34 moves above latch 35 compression spring 40 urges control member 36- about pivot 37 to return latch 3S to its :latching position.

The circular opening in the cover 20 of the left hand circuit breaker 11 and the corresponding circular opening 63 in the base 18 of the right hand circuit breaker 13 of stack 10 may be closed by caps (not shown) which are seated in suitable ridges surrounding these openings.

Common tie bar 17 `is an elongated member of uniform cross-section which is disposed within openings 62 of each of the trip levers 61 of circuit breakers 11-13. For this purpose a round opening 63 is formed in the closed side of base 18 and an aligned `similar round opening (not shown) is formed in cover 20.

With all of the circuit breakers in the closed position of FIGURE 3, should yan overload condition occur in any of the circuit breakers 11-13 the latch 35 of the overloaded circuit breaker will move to the right thereby releasing its associated latch tip 34 so that operating spring 33 will force cradle 31 to rotate clockwise about pivot 32 to the tripped position of FIGURE 4.

During this movement of cradle 31, roller 59 carried thereby will engage trip lever 61 causing a counterclockwise movement thereof about pin 37 This counterclockw-ise movement of the trip lever 61 of the overloaded phase is transmitted through tie bar 17 so that the trip levers 61 of the circuit breakers which are not overloaded will also move counterclockwise about their pivots 37 into engagement with their respective control members 36. These respective control members 36 will in this manner be pivoted in a counterclockwise direction about pivot 37 and the latches 35 carried thereby will release their associated latch tips 34 thereby bringing about the automatic tripping of the phases which have not been subjected to the overload conditions.

Thus, I have provided a novel construction for a single phase circuit breaker trip lever 61 which permits any number of identical circuit breakers 11 to be stacked side by side with their manual operating handles 14 tied together by cap 15 and pin 16 for simultaneous manual operation. The automatic trip units 100, comprising control member 36 as well as magnet 38 and cooperating armature 47, are mechanically coordinated by means of trip levers 61 and common `member 17 Common member 17 is -a simple rod-like member whose length is determined by the number of circuit breakers in the stack.

The common pivot point 37 for control member 36 and trip lever 61 provides :the optimum mechanical connection between control member 36 and trip lever 61 for minimal operating force requirements. The operating force requirements are further reduced by having roller 59 engage trip lever 6l for imparting motion to the latter upon the automatic tripping of any of the circuit breakers 11-13 of stack 10.

Although I have here described preferred embodiments of my novel invention, many variations and modifications will now be apparent to those skilled in the art, and I therefore prefer to be limited, not by the specific disclosure herein, but only by the appending claims.

I claim:

1. The combination comprising a plurality of individual circuit breakers stacked side by side, and a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a 'latchable means and means biasing said latchable means to a first position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position; said control member normally Ibeing in a third position, wherein said latch is in latching position, and movable to a fourth position due to the occurrence of an overload condition whereby said latch is unlatched; said trip member of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their associated control members thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a rst of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereby reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit breakers; each of said trip members being mounted to the same pivot as their associated control members.

2. The combination comprising a plurality of individual circuit breakers stacked side by side, and a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a first position, a latch for maintaining said latchable means in a second position, a control member having said latch :onnected thereto, a trip member movable by said latchable means upon operation thereof from said second po- ;ition to said first position; said control member normal- .y being in a third position, wherein said latch is in latching position and movable to afourth position due to the occurrence of an overload condition whereby said latch is unlatched; said trip member of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their associated control members and thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a first of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; the latchable means of each of said circuit breakers being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said roller being engageable with said trip member to reduce the friction between each of said latchable means and its associated trip member.

3. The combination comprising a plurality of individual circuit breakers stacked side by side, and a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a lirst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position; said control member normally being in a third position, wherein said latch is in latching position, and movable to a fourth position due to the occurrence of an overload condition whereby said latch is unlatched; said trip mem-ber of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their associated control members and thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a first of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said plurality of circuit breakers being of identical external construction; said common element comprising an elongated member of uniform cross-section throughout the length thereof; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereby reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit 7 breakers; each of said trip members being mounted to the same pivot as their associated control members.

4. The combination comprising a plurality of individual circuit breakers stacked side by side, and a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable Contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a first position, a control member having said latch connected thereto, a tnip member movable by said latchable means upon operation thereof from said second position to said rst position; said control member normally being in a third position, wherein said latch is in latching position, and movable to a fourth position due to the occurrence of an overload condition whereby said latch is unlatched; said trip member of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their asociated control members and thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a rst of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said plurality of circuit breakers being of identical external construction; said common element comprising an elongated member of uniform cross-section throughout the length thereof; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereby reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit breakers; each of said trip members being mounted to the same pivot as their associated control members; the latchable means of each `of said circuit breakers being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said roller being engageable with said trip member to reduce the friction between each of said latchable means and its associated trip member.

5. The combination comprising a plurality of individual circuit breakers, at least three in number, stacked side by side, land a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable contact arm, -a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a iirst position, a latch for maintaining said latchable means in second position, a control member having said latch connected thereto, a trip member movable by said latchable -means upon operation thereof from said second position to said rst position; said control member normally being in a third position, wherein said latch is in latching position, and movable to a fourth position due to the occurrence `of an overload condition, whereby said latch is unlatched; said trip member of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their associated control members and thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a first of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their latches and trip the remaining circuit breakers; each of said control members being mounted on a pivot whereby each of said control mebers is movable -as an entity thereby reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit breakers; each of said trip members being mounted to the same pivot as their associated control members.

6. The combination comprising a plurality of individual circuit breakers, at least three in number, stacked side by side, and a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable contact arm, a pair of cooperating contacts one of Which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a rst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said iirst position; said control member normally being in a third position, wherein said latch is in latching position, and movable to a fourth position due to the occurrence of an overload condition, whereby said latch is unlatched; said trip member of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their associated control members and thereby unlatching said latch; said latchable means when un- ]atched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a rst of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member or" all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respeotive control members to unlatch their respective latches and trip the remaining circuit breakers; the latchable means of each of said circuit breakers being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said roller being engageable with said trip member to reduce the friction between each of said latchable means and its associated trip member.

7. The combination comprising a plurality of individual circuit breakers, at least three in number, stacked side by side, and a common element extending between said plurality of circuit breakers whereby the tripping of any one of said circuit breakers due to an overload therein will cause the remaining ones of said circuit breakers to trip open; each of said circuit breakers comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said rst position; said control member normally being in a third position, wherein said latch is in latching position, and movable to `a fourth position due to the occurrence of an overload condition whereby said latch is unlatched; said trip member of one of said plurality of circuit breakers, when moved by its associated latchable means, causing movement of the trip member of each remaining of said plurality of circuit breakers; movement of the trip members of each remaining of said plurality of circuit breakers causing engagement between the last recited trip members and their associated control members and thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said common element being positioned within an opening in the trip members of each of said circuit breakers whereby all of said trip members are operable in unison so that upon the tripping of a rst of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said plurality of circuit breakers being of identical eX- ternal construction; said common element comprising an elongated member of uniform cross-section throughout the length thereof; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereof reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit breakers; each of said trip members being mounted to the same pivot as their associated control members.

8. A circuit breaker comprising a movable Contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a iirst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position; said control member normally being in a third position, wherein said latch is in latching position, and movable to a fourth position due to the occurrence of an overloaded condition wherein said latch is unlatched; said trip member when -moved by said latchable member engaging said control member; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said trip member having an opening therein whereby said trip member may be connected to at least one additional circuit breaker by a common member due to the occurrence of an overload thereat will move the trip members of the other circuit breakers to cause the tripping of the other circuit breakers; said control member and said trip member both being mounted to the same pivot.

9. A circuit breaker comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a iirst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable Iby said latchable means upon operation thereof from said second position to said `first position; said control member normally being in a third position,

wherein said latch is in latching position, and movable to a fourth position due to the occurrence of an overloaded condition wherein said latch is unlatched; said trip member when moved by said latchable member engaging said control member; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; said trip member having an opening therein whereby said trip member may be connected to at least one additional circuit vbreaker by a common memvber due to the occurrence of an overload thereat will move the trip members of the other circuit breakers tocause the tripping of the other circuit breakers; said control member and said trip member both being mounted to the same pivot; said latchable means being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said trip roller being engageable with said trip member to reduce the friction between said latchable means and said trip member.

10. A circuit breaker comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a rst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position, said control member normally being in a third position, wherein said latch is in latching position, and movafble to a fourth position due to the occurrence of an overloaded condition wherein said latch is unlatched; said trip member when moved by said latchable member engaging said control member; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; Said trip member being connectable to a trip member of each of at least one additional circuit breaker whereby the tripping of one of said circuit breakers due to! the occurrence of an overload thereat will move the trip members of the other circuit breakers to cause the tripping of the other circuit rbreakers; said latchable means being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said trip roller being engageable with said trip member to reduce the `friction between said latchable means and Said trip member.

11. A circuit breaker comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a iirst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position, said control member normally being in a third position, and movable to a fourth position due to the occurrence of an overloaded condition wherein said latch is unlatched; said trip member when moved by said latchable member engaging said control member and thereby unlatching said latch; said latchable means when unlatched permitting said operating mechanism to Ybring about the disengagement of said cooperating contacts; said trip member being connectable to a trip member of each of at least one yadditional circuit breaker whereby the tripping of one of said circuit breakers due to the occurrence of an overload thereat will move the trip members of the other circuit breakers to' cause the tripping of the other ciricuit breakers; said latchable means being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said trip roller being engageable with said trip member to reduce the friction between said latchable means and said trip member; said 1l control member and said trip member both being mounted to the same pivot.

12. A plurality of circuit breakers stacked side by side, each comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a iirst position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation theerof from said second position to said iirst position; said control member normally being in a t-hird position, wherein said latch is in latch-ing position, and movable to la fourth position due to the occurrence of an overload condition wherein said latch is unlatched; said trip member when moved by said latchable member engaging said control member; said latchable means when unlatched permitting said operating mechanism to bring about the `disengagement of said cooperating contacts; means interconnecting the trip members of each o-f said circuit breakers: whereby all of said trip means are operable in unison so that upon the tripping of a iirst of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlateh their respective latches and trip the remaining circuit breakers; the latchable means of each of said circuit breakers being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said roller being engageable with said trip member tol reduce the friction between each of said latchable means and its associated trip member.

13. A plurality of circuit breaker stacked side by side, each comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a first position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said rst position; said control member normally being in a third position, wherein said latch is in latching lposition, and movable to a fourth position due to the occurrence of an overload condition wherein said latch is unlatched; said latchable means 'when unlatched permitting said operating mechanism to bring about the dis-- engagement of said cooperating contacts; means interconnecting the trip members of each of said circuit breakers whereby all of said trip means are operable in unison so that upon the tripping of a iirst of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereby reducing the mechanical force required at the overload circuit breaker to trip the remaining circuit breakers; eac-h of said trip members being mounted to the same pivot as their associated control members.

14. A plurality of circuit breakers, at least three in number stacked side by side, each comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a rst position, -a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position; said control member normally being in a third position, wherein said latch is in latohing position and movable to a fourth position due to the occurrence of an overload condition, wherein said latch is unlatched; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; means interconnecting the trip members of each of said circuit breakers whereby all of said trip means are operable in unison so that upon the tripping of a first of said circuit breakers due to the occurrence of an overload threreat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; the latchable means of each of said circuit breakers being comprised of a cradle and a roller mounted thereto; said cradle being engageable by said latch and said roller being engageable with said trip member to reduce the friction between each of said latchable means and its associated trip member.

15. A plurality of circuit breakers, at lleast three in number stacked side by side, each comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a iirst position, `a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said first position; said control member normally being in a third position, wherein said latch is in latching position and movable to a fourth position due to the occurrence of an overload condition, wherein said latch is unlatched; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said cooperating contacts; means interconnecting the trip members of each of said circuit breakers whereby all of said trip means are operable in unison so that upon the tripping of a first of said circuit breakers due to the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereby reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit breakers; each of said trip members being mounted to the same pivot as their associated control members.

16. A plurality of circuit breakers, at least three in number stacked side by side, each comprising a movable contact arm, a pair of cooperating contacts one of which is mounted to said contact arm, an operating mechanism including a latchable means and means biasing said latchable means to a first position, a latch for maintaining said latchable means in a second position, a control member having said latch connected thereto, a trip member movable by said latchable means upon operation thereof from said second position to said rst position; said control member normally being in a third position, wherein said latch is in latching position and movable tol a fourth position due to the occurrence of an overload condition, wherein said latch is unlatched; said latchable means when unlatched permitting said operating mechanism to bring about the disengagement of said :cooperating contacts; means interconnecting the trip members of each of said circuit breakers whereby all of said trip means are operable in unison so that upon the tripping of a first of said circuit breakers due lto the occurrence of an overload thereat the operating mechanism thereof shall cause movement of the trip member of all of said circuit breakers thereby causing the trip member of the remaining circuit breakers to engage their respective control members to unlatch their respective latches and trip the remaining circuit breakers; each of said plurality of circuit breakers being of identical external construction; each of said control members being mounted on a pivot whereby each of said control members is movable as an entity thereby reducing the mechanical force required at the overloaded circuit breaker to trip the remaining circuit breakers; each of said trip members being mounted to the same pivot as their associated control members.

References Cited in the le of this patent UNITED STATES PATENTS