ELECTRICAL PANELBOARD HAVING PLUG-IN LINE AND LOAD CONNECTIONS TO CIRCUIT BREAKER
United States Patent 3619727
The panelboard has flat bus bars stacked in a direction perpendicular to a mounting pan and is provided with plug-in load-side connectors. Circuit breakers having line-side jaws for plugging onto the bus bars by movement parallel to the mounting pan are provided with stab terminals for plugging into jaws of the connectors. Load wires are secured to terminals of the connectors and need not be disturbed when a circuit breaker is plugged into or removed from the panelboard.
US Patent References:
Panel board contact assembly
Jacobs - October 1968 - 3404315
Plug-in electrical receptacle
Keller - June 1953 - 2641746
Panelboard construction
Fore - June 1958 - 2837699
Panel board arrangement for embedded load terminals
Edmunds - May 1961 - 2986676
Electrical panelboard
Jorgensen - November 1967 - 3354357
Panel board contact assembly
Jacobs - October 1968 - 3404315
Plug-in electrical receptacle
Keller - June 1953 - 2641746
Panelboard construction
Fore - June 1958 - 2837699
Panel board arrangement for embedded load terminals
Edmunds - May 1961 - 2986676
Electrical panelboard
Jorgensen - November 1967 - 3354357
Application Number:
05/002149
Publication Date:
11/09/1971
Filing Date:
01/12/1970
View Patent Images:
Export Citation:
Assignee:
Square D Company (Park Ridge, IL)
Primary Class:
Other Classes:
361/650
International Classes:
H02B1/056; H02B1/015; H02B1/04
Field of Search:
317/113,118,119 339/191,192
Primary Examiner:
Myers, Lewis H.
Assistant Examiner:
Tolin, Gerald P.
Claims:
I claim
1. An electrical panelboard and circuit breaker combination comprising an electric circuit breaker including an elongated generally rectangular molded case, plug-on jaw line terminal means accessible from one end portion of the case longitudinally thereof, and plug-in load terminal means extending from a rear portion of the case adjacent the other end portion transversely of the direction of access of the plug-in line terminal means, and an electrical panelboard including box having a rear wall, an elongated bus bar secured in the box in spaced parallel relationship to the rear wall, and a plug-in load-side connector secured in the box in spaced relationship to the bus bar in a direction parallel to the rear wall, the plug-in load-side connector including electrically interconnected load wire receiving terminal means and circuit breaker receiving plug-in terminal means, and the circuit breaker receiving plug-in terminal means facing in a direction parallel to the rear wall and away from the bus bar and electrically engaging the circuit breaker plug-in load terminal means upon movement of the circuit breaker in a direction parallel to the rear wall toward the bus bar and plugging of the circuit breaker plug-on jaw line terminal means on the bus bar.
2. An electrical panelboard and circuit breaker combination as claimed in claim 1 including a mounting pan secured to the rear wall of the box and wherein the plug-in load-side connector is secured to the mounting pan as a separate unit and includes a base having a compartment therein and a cover secured to the base, the load wire receiving terminal means and the circuit breaker receiving plug-in terminal means being disposed in the compartment in the base and the cover having a slot therein providing access to the terminal means in the compartment.
3. An electrical panelboard and circuit breaker combination as claimed in claim 1 and wherein the circuit breaker and the plug-in load-side connector are provided with cooperative racking means for racking the circuit breaker to plug and unplug the line terminal means respectively on and off the bus bar and to plug and unplug the load terminal means respectively in and out of the circuit breaker receiving plug-in terminal means.
4. An electrical panelboard and circuit breaker combination as claimed in claim 1 wherein the plug-in load-side connector includes a generally L-shaped terminal strap, the load wire receiving terminal means is secured to one leg portion of the terminal strap, and the circuit breaker receiving plug-in terminal means is a plug-in jaw member secured to the other leg portion of the terminal strap.
5. An electrical panelboard and circuit breaker combination as claimed in claim 1 wherein the circuit breaker includes three plug-on jaw line terminal means accessible from the one end portion of the case longitudinally thereof and three plug-in load terminal means extending from the rear portion of the case adjacent the other end portion, the electrical panelboard includes three bus bars parallel to and aligned with each other and spaced successively greater distances from the rear wall, and the plug-in load-side connector includes a case having three compartments, three load wire receiving terminal means, and three circuit breaker receiving plug-in terminal means, each of the three compartments having one load wire receiving terminal means and one circuit breaker receiving plug-in terminal means disposed therein.
6. An electrical panelboard and circuit breaker combination 5 as claimed in claim 5 wherein the case includes a base and a cover and the base includes two intermediate walls dividing the interior of the case into the three compartments, and a rack member is mounted in one of the intermediate walls.
7. An electrical panelboard and circuit breaker combination as claimed in claim 6 including a stop screw mounted in the other of the intermediate walls.
8. An electrical panelboard and circuit breaker combination as claimed in claim 5 wherein the circuit breaker has a driving cam mounted thereon, the case includes a base and a cover, and the cover has a recess for receiving the driving cam.
9. An electrical panelboard and circuit breaker combination as claimed in claim 8 including a frame member mounted on the cover, partially lining the recess, and having a pair of opposed bearing surfaces engageable by the driving cam.
1. An electrical panelboard and circuit breaker combination comprising an electric circuit breaker including an elongated generally rectangular molded case, plug-on jaw line terminal means accessible from one end portion of the case longitudinally thereof, and plug-in load terminal means extending from a rear portion of the case adjacent the other end portion transversely of the direction of access of the plug-in line terminal means, and an electrical panelboard including box having a rear wall, an elongated bus bar secured in the box in spaced parallel relationship to the rear wall, and a plug-in load-side connector secured in the box in spaced relationship to the bus bar in a direction parallel to the rear wall, the plug-in load-side connector including electrically interconnected load wire receiving terminal means and circuit breaker receiving plug-in terminal means, and the circuit breaker receiving plug-in terminal means facing in a direction parallel to the rear wall and away from the bus bar and electrically engaging the circuit breaker plug-in load terminal means upon movement of the circuit breaker in a direction parallel to the rear wall toward the bus bar and plugging of the circuit breaker plug-on jaw line terminal means on the bus bar.
2. An electrical panelboard and circuit breaker combination as claimed in claim 1 including a mounting pan secured to the rear wall of the box and wherein the plug-in load-side connector is secured to the mounting pan as a separate unit and includes a base having a compartment therein and a cover secured to the base, the load wire receiving terminal means and the circuit breaker receiving plug-in terminal means being disposed in the compartment in the base and the cover having a slot therein providing access to the terminal means in the compartment.
3. An electrical panelboard and circuit breaker combination as claimed in claim 1 and wherein the circuit breaker and the plug-in load-side connector are provided with cooperative racking means for racking the circuit breaker to plug and unplug the line terminal means respectively on and off the bus bar and to plug and unplug the load terminal means respectively in and out of the circuit breaker receiving plug-in terminal means.
4. An electrical panelboard and circuit breaker combination as claimed in claim 1 wherein the plug-in load-side connector includes a generally L-shaped terminal strap, the load wire receiving terminal means is secured to one leg portion of the terminal strap, and the circuit breaker receiving plug-in terminal means is a plug-in jaw member secured to the other leg portion of the terminal strap.
5. An electrical panelboard and circuit breaker combination as claimed in claim 1 wherein the circuit breaker includes three plug-on jaw line terminal means accessible from the one end portion of the case longitudinally thereof and three plug-in load terminal means extending from the rear portion of the case adjacent the other end portion, the electrical panelboard includes three bus bars parallel to and aligned with each other and spaced successively greater distances from the rear wall, and the plug-in load-side connector includes a case having three compartments, three load wire receiving terminal means, and three circuit breaker receiving plug-in terminal means, each of the three compartments having one load wire receiving terminal means and one circuit breaker receiving plug-in terminal means disposed therein.
6. An electrical panelboard and circuit breaker combination 5 as claimed in claim 5 wherein the case includes a base and a cover and the base includes two intermediate walls dividing the interior of the case into the three compartments, and a rack member is mounted in one of the intermediate walls.
7. An electrical panelboard and circuit breaker combination as claimed in claim 6 including a stop screw mounted in the other of the intermediate walls.
8. An electrical panelboard and circuit breaker combination as claimed in claim 5 wherein the circuit breaker has a driving cam mounted thereon, the case includes a base and a cover, and the cover has a recess for receiving the driving cam.
9. An electrical panelboard and circuit breaker combination as claimed in claim 8 including a frame member mounted on the cover, partially lining the recess, and having a pair of opposed bearing surfaces engageable by the driving cam.
Description:
This invention is an improvement on electrical panelboards of the type disclosed in U.S. Pat. Nos. 3,346,777 and 3,354,357, respectively issued Oct. 10 and Nov. 21, 1967.
An object of the invention is to provide an electrical panelboard and circuit breaker combination in which circuit breakers can be plugged into or removed from an in-service panelboard without disturbance of load wire connections.
Other objects and advantages will become apparent upon consideration of the following specification and drawings in which:
FIG. 1 is a transverse sectional view of an electrical panelboard constructed in accordance with the invention, and including plug-in load-side connectors, the front trim panel and cover being omitted;
FIG. 2 is a view of a smaller one of the plug-in load-side connectors of the panelboard of FIG. 1, taken in the direction of arrows 2--2 of FIG. 1, portions of a cover of the connector being removed;
FIG. 3 is an end view of the connector of FIG. 2, taken in the direction of arrows 3--3;
FIG. 4 is a sectional view taken generally along the line 4--4 of FIG. 2 and including a fragmentary sectional view of an electrical circuit breaker plugged into the connector;
FIG. 5 is a fragmentary sectional view taken along the line 5--5 of FIG. 2;
FIG. 6 is a fragmentary sectional view taken along the line 6--6 of FIG. 2, but omitting the cover;
FIG. 7 is a view of a bracket secured to the circuit breaker of FIG. 4, taken in the direction of arrows 7--7 of FIG. 4;
FIG. 8 is a view of a larger one of the plug-in load-side connectors of the panelboard of FIG. 1, taken in the direction of arrows 8--8 of FIG. 1, a portion of the cover being removed;
FIG. 9 is a sectional view taken along the line 9--9 of FIG. 8 and including a fragmentary sectional view of an electric circuit breaker plugged into the connector; and
FIG. 10 is a fragmentary sectional view taken along the line 10--10 of FIG. 8.
FIG. 1 shows an electrical panelboard 20 including an open-front box 22 and a generally flat mounting pan 24 secured to a rear wall portion 22a of the box in any suitable manner.
As in the aforementioned U.S. Pat. Nos. 3,346,777 and 3,354,357, the panelboard 20 includes three elongated flat bus bars 26 stacked flatwise parallel to the mounting pan 24, separated from each other by a pair of intermediate insulators 27, and disposed between a rear insulator 28 and a front insulator 29. The bus bars and insulators are clamped between a pair of clamping members 30 by a plurality of longitudinally spaced bolts 31 and nuts 32, only one bolt 31 and one nut 32 being shown in FIG. 1. The general arrangement may be better understood by reference to FIGS. 2 and 3 of U.S. Pat. No. 3,354,357. However, in accordance with this invention, the bus bars and insulators are clamped to a spacing channel 34 secured to the mounting pan 24 in any suitable manner, rather than being clamped directly to the mounting pan 24 as in the aforesaid patents.
Also in accordance with this invention, the panelboard 20 is provided with a plurality of plug-in load-side connectors which may be of different sizes, a relatively small connector 35 and a relatively large connector 36 being shown in FIG. 1. There may be a row of connectors 35 extending along the length of the bus bars 26 on one side of the spacing channel 34 and a row of connectors 36 extending along the length of the bus bars 26 on the other side of the spacing channel 34, or the rows may be mixed.
A relatively small three-pole molded-case circuit breaker 37 is plugged at its line end onto the bus bars 26 and at its load end into the connector 35. The basic mechanism of the circuit breaker 37 is essentially the same as that disclosed in U.S. Pat. No. 3,341,791, issued Sept. 12, 1967, the wire-receiving line terminals of the structure of that patent being replaced in the circuit breaker 37 by plug-on jaws, as shown in the aforementioned U.S. Pat. No. 3,346,777, for plugging onto the bus bars 26, and the wire-receiving load terminals of the structure of U.S. Pat. No. 3,341,791 being replaced in the circuit breaker 37 by stab terminals 38, one of which is shown in FIG. 4, for plugging into the connector 35. Thus, the circuit breaker 37 has a generally rectangular molded case with three plug-on jaw line terminal means accessible from one end portion of the case and three plug-in load terminal means 38 extending from a rear portion of the case adjacent the other end portion.
The connector 35 includes a base 39 and a generally flat cover 40 molded of insulating material and secured together by four eyelets or hollow rivets 42. The base 39 has a hollow portion divided into three compartments 39a, 39b and 39c by a pair of intermediate walls 39d and 39e. Each of the three compartments has a generally L-shaped terminal strap 44 secured therein by a screw 45 countersunk in and extending through a rear wall 39f of the base 39 and threaded through an opening in a longer leg portion of the terminal strap 44. A free end portion of a shorter leg portion of each of the terminal straps 44 has a plug-in jaw member 46 secured thereto by a screw 47 extending through the jaw member 46 and threaded into an opening in the terminal strap 44. A free end portion of the longer leg portion of each of the terminal straps 44 has a connector body 48 secured thereto by a screw (not shown) countersunk in and extending through an adjacent portion of the connector body and threaded into an opening in the terminal strap 44. The ends of the compartments 39a, 39b and 39c adjacent the respective connector bodies 48 are open, as shown in FIGS. 3 and 4, and each connector body 48 is provided with a through hole 48a for receiving a load wire (not shown) and a transverse threaded hole in which a clamping screw 50 is mounted for clamping the load wire against a countersunk head of the screw (not shown) securing the connector body to the respective terminal strap 44. (Note the similar arrangement in FIG. 9, hereinafter described, in which the screw securing the connector body to the terminal strap is shown). If desired, an insulating wiring barrier (not shown) may be included in each of the compartments 39a, 39b, and 39c adjacent the inner end of the hole 48a of the respective connector body 48.
The connector 35 is secured to the mounting pan 24 by a plurality of mounting screws (not shown) extending respectively through the hollow rivets 42 and through bushings 52 (FIG. 3) provided respectively in a plurality of mounting foot portions 39g of the base 39 adjacent the inner ends of passageways 39h containing the hollow rivets 42.
Each pole of the three-pole circuit breaker 37 is provided with a terminal strap 54 (FIG. 4) to which the respective stab terminal 38 is secured by a screw 56 extending through a bushing 58 and threaded into the stab terminal 38.
The cover 40 is provided with three slots 40a appropriately shaped for respectively receiving the stab terminals 38 and for receiving a tool such as a screwdriver (not shown) to operate the clamping screws 50. In the installation of the circuit breaker 37 in the electrical panelboard 20, the stab terminals 38 are first received in the plug-in load-side connector 35 perpendicularly to the rear wall 39f of the base 39 respectively between the connector bodies 48 and the plug-in jaw members 46, and are then moved parallel to the rear wall 39f into cooperative engagement respectively with the jaw members 46.
A considerable amount of force is required to move the stab terminals 38 into engagement respectively with the jaw members 46 at the same time the line-side plug-on jaws (not shown), as disclosed in U.S. Pat. No. 3,346,777, are plugged respectively onto the bus bars 26. For this reason, a pair of rack members 60 (FIGS. 2 and 5) is provided in a suitable recess in the intermediate wall 39d of the base 39, a suitable access opening (not shown) being provided in the cover 40, and a generally U-shaped bracket 62 (FIGS. 4 and 7) is secured to the rear of the circuit breaker 37 by rivets (not shown) extending through a pair of holes 62a provided in opposed leg portions 62b and 62c of the bracket. A tool-receiving aperture 62d, for receiving a tool such as a screwdriver, is provided in the bracket 62 adjacent the free end of the leg portion 62b, which is longer than the leg portion 62c. Thus, a screwdriver may be used in conjunction with the bracket 62 and rack members 60 to pry the circuit breaker 37 into and out of cooperative engagement with the bus bars 26 and jaw members 46. The two rack members 60 may be made in one piece, but preferably two rack members, each of a thickness one-half of their combined thickness, are provided for facility in stamping them from sheet steel.
Unintentional disengagement of the plug-on jaws (not shown) and the stab terminals 38 of the circuit breaker 37 respectively from the bus bars 26 and the jaw members 46 may be prevented by a stop screw 64 mounted in a nut 65 frictionally secured in a suitable recess in the intermediate wall 39e of the base 39. After the circuit breaker 37 is plugged in, the stop screw 64 may be turned outwardly, a suitable access hole being provided in the cover 40, until the outer end portion of the stop screw is aligned with free end portion of the leg portion 62c of the bracket 62 so as to prevent disengagement of the circuit breaker 37.
A relatively large circuit breaker 66 is plugged at its line end onto the bus bars 26 and at its load end into the plug-in load-side connector 36. The basic mechanism of the circuit breaker 66 is essentially the same as that disclosed in U.S. Pat. No. 3,355,685, issued Nov. 28, 1967, the wire-receiving line terminals of the structure of that patent being replaced in the circuit breaker 66 by plug-on jaws, as shown in the aforementioned U.S. Pat. No. 3,346,777, for plugging onto the bus bars 26, and the wire-receiving load terminals of the structure of U.S. Pat. No. 3,355,685 being replaced in the circuit breaker 66 by stab terminals 68, one of which is shown in FIG. 9, for plugging into the connector 36. Thus, the circuit breaker 66 has a generally rectangular molded case with three plug-on jaw line terminal means accessible from one end portion of the case and three plug-in load terminal means 68 extending from a rear portion of the case adjacent the other end portion.
The connector 36 includes a base 69 and a cover 70 molded of insulating material and secured together by four eyelets or hollow rivets 72, one of which is indicated in FIG. 8 and another of which is indicated in FIG. 10, in the same manner that the rivets 42 secure together the base 39 and cover 40 (FIG. 3). The base 69 has a hollow portion divided into three compartments by a pair of intermediate walls, one of which is indicated at 69a. Each of the three compartments has a generally L-shaped terminal strap 74 secured therein by a pair of screws 75 extending through a rear wall 69b of the base 69 and threaded through an opening in a longer leg portion of the terminal strap 74. A free end portion of a shorter leg portion of each of the terminal straps 74 has a plug-in jaw member 76 secured thereto by a screw 77 extending through the jaw member 76 and threaded into an opening in the terminal strap 74. A free end portion of the longer leg portion of each of the terminal straps 74 has a connector body 78 secured thereto by a screw 79 countersunk in and extending through an adjacent portion of the connector body and threaded into an opening in the terminal strap 74.
Each connector body 78 is provided with a through hole 78a for receiving a load wire (not shown) and a transverse threaded hole in which a pair of clamping screws 80 is mounted for clamping the load wire against the head of the screw 79.
Each jaw member 76 is provided with a spring member 81 to aid in maintaining contact pressure on the respective stab terminal 68 of the circuit breaker 66.
The cover 70 has a smaller cover 82 removably secured thereto by a pair of screws 83 threaded respectively into a pair of inserts 84 (FIG. 10), the cover 82 being removed before tightening of the clamping screws 80 and replaced thereafter.
The connector 36 is secured to the mounting pan 24 by a plurality of mounting screws (not shown) extending respectively through the hollow rivets 72.
Each pole of the three-pole circuit breaker 66 is provided with a terminal strap 85 to which the respective stab terminal 68 is secured by a screw 86 extending through a reinforcing plate 87 and the terminal strap 85 and threaded into an opening in the stab terminal 68.
The cover 70 is provided with three apertures 70a for respectively receiving the stab terminals 68. The circuit breaker 66 is provided with a bracket and driving cam device similar to that disclosed in copending application, Ser. No. 802,102, filed Feb. 25, 1969, and assigned to the assignee of this application. Thus, a bracket 88 secured to the circuit breaker 66 rotatably supports a driving pin 90 having a cylindrical cam 91 and an indicating plate 92 keyed thereto for rotation therewith.
The cover 70 is provided with a recess 70b surrounded by a frame member 94 secured to the cover 70 by a plurality of screws 95. If desired, the screws 83 may each be provided with a fiber washer 96 to retain the screws 83 in assembled relationship with the cover 82 when it is removed from the cover 70 to provide access to the clamping screws 80.
In the installation of the circuit breaker 66, the cam 91 is received in the recess 70b as the stab terminals 68 are received by the connector 36 respectively through the apertures 70a. The drive pin 90 may then be turned in one direction with a hexagonal socket wrench to turn the cam 91 which bears against the frame member 94 to move the circuit breaker 66 parallel to the mounting pan 24 to plug the stab terminals 68 respectively into the jaw members 76 and to plug the line-side jaws (not shown), as disclosed in U.S. Pat. No. 3,346,777, respectively onto the bus bars 26. The drive pin 90 may be turned in an opposite direction to disengage the circuit breaker 66 from the bus bars 26 and jaw member 76.
The circuit breakers 37 and 66 may be installed in or removed from the electrical panelboard 20 without disturbing load wires (not shown) clamped respectively to the terminal straps 44 and 74 of the connectors 35 and 36 by clamping screws 50 and 80.
In actual practice, more wiring space may be provided in an electrical panelboard than is shown in FIG. 1 between the connector 36 and the adjacent sidewall of the box 22.
An object of the invention is to provide an electrical panelboard and circuit breaker combination in which circuit breakers can be plugged into or removed from an in-service panelboard without disturbance of load wire connections.
Other objects and advantages will become apparent upon consideration of the following specification and drawings in which:
FIG. 1 is a transverse sectional view of an electrical panelboard constructed in accordance with the invention, and including plug-in load-side connectors, the front trim panel and cover being omitted;
FIG. 2 is a view of a smaller one of the plug-in load-side connectors of the panelboard of FIG. 1, taken in the direction of arrows 2--2 of FIG. 1, portions of a cover of the connector being removed;
FIG. 3 is an end view of the connector of FIG. 2, taken in the direction of arrows 3--3;
FIG. 4 is a sectional view taken generally along the line 4--4 of FIG. 2 and including a fragmentary sectional view of an electrical circuit breaker plugged into the connector;
FIG. 5 is a fragmentary sectional view taken along the line 5--5 of FIG. 2;
FIG. 6 is a fragmentary sectional view taken along the line 6--6 of FIG. 2, but omitting the cover;
FIG. 7 is a view of a bracket secured to the circuit breaker of FIG. 4, taken in the direction of arrows 7--7 of FIG. 4;
FIG. 8 is a view of a larger one of the plug-in load-side connectors of the panelboard of FIG. 1, taken in the direction of arrows 8--8 of FIG. 1, a portion of the cover being removed;
FIG. 9 is a sectional view taken along the line 9--9 of FIG. 8 and including a fragmentary sectional view of an electric circuit breaker plugged into the connector; and
FIG. 10 is a fragmentary sectional view taken along the line 10--10 of FIG. 8.
FIG. 1 shows an electrical panelboard 20 including an open-front box 22 and a generally flat mounting pan 24 secured to a rear wall portion 22a of the box in any suitable manner.
As in the aforementioned U.S. Pat. Nos. 3,346,777 and 3,354,357, the panelboard 20 includes three elongated flat bus bars 26 stacked flatwise parallel to the mounting pan 24, separated from each other by a pair of intermediate insulators 27, and disposed between a rear insulator 28 and a front insulator 29. The bus bars and insulators are clamped between a pair of clamping members 30 by a plurality of longitudinally spaced bolts 31 and nuts 32, only one bolt 31 and one nut 32 being shown in FIG. 1. The general arrangement may be better understood by reference to FIGS. 2 and 3 of U.S. Pat. No. 3,354,357. However, in accordance with this invention, the bus bars and insulators are clamped to a spacing channel 34 secured to the mounting pan 24 in any suitable manner, rather than being clamped directly to the mounting pan 24 as in the aforesaid patents.
Also in accordance with this invention, the panelboard 20 is provided with a plurality of plug-in load-side connectors which may be of different sizes, a relatively small connector 35 and a relatively large connector 36 being shown in FIG. 1. There may be a row of connectors 35 extending along the length of the bus bars 26 on one side of the spacing channel 34 and a row of connectors 36 extending along the length of the bus bars 26 on the other side of the spacing channel 34, or the rows may be mixed.
A relatively small three-pole molded-case circuit breaker 37 is plugged at its line end onto the bus bars 26 and at its load end into the connector 35. The basic mechanism of the circuit breaker 37 is essentially the same as that disclosed in U.S. Pat. No. 3,341,791, issued Sept. 12, 1967, the wire-receiving line terminals of the structure of that patent being replaced in the circuit breaker 37 by plug-on jaws, as shown in the aforementioned U.S. Pat. No. 3,346,777, for plugging onto the bus bars 26, and the wire-receiving load terminals of the structure of U.S. Pat. No. 3,341,791 being replaced in the circuit breaker 37 by stab terminals 38, one of which is shown in FIG. 4, for plugging into the connector 35. Thus, the circuit breaker 37 has a generally rectangular molded case with three plug-on jaw line terminal means accessible from one end portion of the case and three plug-in load terminal means 38 extending from a rear portion of the case adjacent the other end portion.
The connector 35 includes a base 39 and a generally flat cover 40 molded of insulating material and secured together by four eyelets or hollow rivets 42. The base 39 has a hollow portion divided into three compartments 39a, 39b and 39c by a pair of intermediate walls 39d and 39e. Each of the three compartments has a generally L-shaped terminal strap 44 secured therein by a screw 45 countersunk in and extending through a rear wall 39f of the base 39 and threaded through an opening in a longer leg portion of the terminal strap 44. A free end portion of a shorter leg portion of each of the terminal straps 44 has a plug-in jaw member 46 secured thereto by a screw 47 extending through the jaw member 46 and threaded into an opening in the terminal strap 44. A free end portion of the longer leg portion of each of the terminal straps 44 has a connector body 48 secured thereto by a screw (not shown) countersunk in and extending through an adjacent portion of the connector body and threaded into an opening in the terminal strap 44. The ends of the compartments 39a, 39b and 39c adjacent the respective connector bodies 48 are open, as shown in FIGS. 3 and 4, and each connector body 48 is provided with a through hole 48a for receiving a load wire (not shown) and a transverse threaded hole in which a clamping screw 50 is mounted for clamping the load wire against a countersunk head of the screw (not shown) securing the connector body to the respective terminal strap 44. (Note the similar arrangement in FIG. 9, hereinafter described, in which the screw securing the connector body to the terminal strap is shown). If desired, an insulating wiring barrier (not shown) may be included in each of the compartments 39a, 39b, and 39c adjacent the inner end of the hole 48a of the respective connector body 48.
The connector 35 is secured to the mounting pan 24 by a plurality of mounting screws (not shown) extending respectively through the hollow rivets 42 and through bushings 52 (FIG. 3) provided respectively in a plurality of mounting foot portions 39g of the base 39 adjacent the inner ends of passageways 39h containing the hollow rivets 42.
Each pole of the three-pole circuit breaker 37 is provided with a terminal strap 54 (FIG. 4) to which the respective stab terminal 38 is secured by a screw 56 extending through a bushing 58 and threaded into the stab terminal 38.
The cover 40 is provided with three slots 40a appropriately shaped for respectively receiving the stab terminals 38 and for receiving a tool such as a screwdriver (not shown) to operate the clamping screws 50. In the installation of the circuit breaker 37 in the electrical panelboard 20, the stab terminals 38 are first received in the plug-in load-side connector 35 perpendicularly to the rear wall 39f of the base 39 respectively between the connector bodies 48 and the plug-in jaw members 46, and are then moved parallel to the rear wall 39f into cooperative engagement respectively with the jaw members 46.
A considerable amount of force is required to move the stab terminals 38 into engagement respectively with the jaw members 46 at the same time the line-side plug-on jaws (not shown), as disclosed in U.S. Pat. No. 3,346,777, are plugged respectively onto the bus bars 26. For this reason, a pair of rack members 60 (FIGS. 2 and 5) is provided in a suitable recess in the intermediate wall 39d of the base 39, a suitable access opening (not shown) being provided in the cover 40, and a generally U-shaped bracket 62 (FIGS. 4 and 7) is secured to the rear of the circuit breaker 37 by rivets (not shown) extending through a pair of holes 62a provided in opposed leg portions 62b and 62c of the bracket. A tool-receiving aperture 62d, for receiving a tool such as a screwdriver, is provided in the bracket 62 adjacent the free end of the leg portion 62b, which is longer than the leg portion 62c. Thus, a screwdriver may be used in conjunction with the bracket 62 and rack members 60 to pry the circuit breaker 37 into and out of cooperative engagement with the bus bars 26 and jaw members 46. The two rack members 60 may be made in one piece, but preferably two rack members, each of a thickness one-half of their combined thickness, are provided for facility in stamping them from sheet steel.
Unintentional disengagement of the plug-on jaws (not shown) and the stab terminals 38 of the circuit breaker 37 respectively from the bus bars 26 and the jaw members 46 may be prevented by a stop screw 64 mounted in a nut 65 frictionally secured in a suitable recess in the intermediate wall 39e of the base 39. After the circuit breaker 37 is plugged in, the stop screw 64 may be turned outwardly, a suitable access hole being provided in the cover 40, until the outer end portion of the stop screw is aligned with free end portion of the leg portion 62c of the bracket 62 so as to prevent disengagement of the circuit breaker 37.
A relatively large circuit breaker 66 is plugged at its line end onto the bus bars 26 and at its load end into the plug-in load-side connector 36. The basic mechanism of the circuit breaker 66 is essentially the same as that disclosed in U.S. Pat. No. 3,355,685, issued Nov. 28, 1967, the wire-receiving line terminals of the structure of that patent being replaced in the circuit breaker 66 by plug-on jaws, as shown in the aforementioned U.S. Pat. No. 3,346,777, for plugging onto the bus bars 26, and the wire-receiving load terminals of the structure of U.S. Pat. No. 3,355,685 being replaced in the circuit breaker 66 by stab terminals 68, one of which is shown in FIG. 9, for plugging into the connector 36. Thus, the circuit breaker 66 has a generally rectangular molded case with three plug-on jaw line terminal means accessible from one end portion of the case and three plug-in load terminal means 68 extending from a rear portion of the case adjacent the other end portion.
The connector 36 includes a base 69 and a cover 70 molded of insulating material and secured together by four eyelets or hollow rivets 72, one of which is indicated in FIG. 8 and another of which is indicated in FIG. 10, in the same manner that the rivets 42 secure together the base 39 and cover 40 (FIG. 3). The base 69 has a hollow portion divided into three compartments by a pair of intermediate walls, one of which is indicated at 69a. Each of the three compartments has a generally L-shaped terminal strap 74 secured therein by a pair of screws 75 extending through a rear wall 69b of the base 69 and threaded through an opening in a longer leg portion of the terminal strap 74. A free end portion of a shorter leg portion of each of the terminal straps 74 has a plug-in jaw member 76 secured thereto by a screw 77 extending through the jaw member 76 and threaded into an opening in the terminal strap 74. A free end portion of the longer leg portion of each of the terminal straps 74 has a connector body 78 secured thereto by a screw 79 countersunk in and extending through an adjacent portion of the connector body and threaded into an opening in the terminal strap 74.
Each connector body 78 is provided with a through hole 78a for receiving a load wire (not shown) and a transverse threaded hole in which a pair of clamping screws 80 is mounted for clamping the load wire against the head of the screw 79.
Each jaw member 76 is provided with a spring member 81 to aid in maintaining contact pressure on the respective stab terminal 68 of the circuit breaker 66.
The cover 70 has a smaller cover 82 removably secured thereto by a pair of screws 83 threaded respectively into a pair of inserts 84 (FIG. 10), the cover 82 being removed before tightening of the clamping screws 80 and replaced thereafter.
The connector 36 is secured to the mounting pan 24 by a plurality of mounting screws (not shown) extending respectively through the hollow rivets 72.
Each pole of the three-pole circuit breaker 66 is provided with a terminal strap 85 to which the respective stab terminal 68 is secured by a screw 86 extending through a reinforcing plate 87 and the terminal strap 85 and threaded into an opening in the stab terminal 68.
The cover 70 is provided with three apertures 70a for respectively receiving the stab terminals 68. The circuit breaker 66 is provided with a bracket and driving cam device similar to that disclosed in copending application, Ser. No. 802,102, filed Feb. 25, 1969, and assigned to the assignee of this application. Thus, a bracket 88 secured to the circuit breaker 66 rotatably supports a driving pin 90 having a cylindrical cam 91 and an indicating plate 92 keyed thereto for rotation therewith.
The cover 70 is provided with a recess 70b surrounded by a frame member 94 secured to the cover 70 by a plurality of screws 95. If desired, the screws 83 may each be provided with a fiber washer 96 to retain the screws 83 in assembled relationship with the cover 82 when it is removed from the cover 70 to provide access to the clamping screws 80.
In the installation of the circuit breaker 66, the cam 91 is received in the recess 70b as the stab terminals 68 are received by the connector 36 respectively through the apertures 70a. The drive pin 90 may then be turned in one direction with a hexagonal socket wrench to turn the cam 91 which bears against the frame member 94 to move the circuit breaker 66 parallel to the mounting pan 24 to plug the stab terminals 68 respectively into the jaw members 76 and to plug the line-side jaws (not shown), as disclosed in U.S. Pat. No. 3,346,777, respectively onto the bus bars 26. The drive pin 90 may be turned in an opposite direction to disengage the circuit breaker 66 from the bus bars 26 and jaw member 76.
The circuit breakers 37 and 66 may be installed in or removed from the electrical panelboard 20 without disturbing load wires (not shown) clamped respectively to the terminal straps 44 and 74 of the connectors 35 and 36 by clamping screws 50 and 80.
In actual practice, more wiring space may be provided in an electrical panelboard than is shown in FIG. 1 between the connector 36 and the adjacent sidewall of the box 22.