CA1225420A - Automated q-line circuit breaker - Google Patents
Automated q-line circuit breakerInfo
- Publication number
- CA1225420A CA1225420A CA000470743A CA470743A CA1225420A CA 1225420 A CA1225420 A CA 1225420A CA 000470743 A CA000470743 A CA 000470743A CA 470743 A CA470743 A CA 470743A CA 1225420 A CA1225420 A CA 1225420A
- Authority
- CA
- Canada
- Prior art keywords
- case
- armature
- cradle
- circuit breaker
- latch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
AUTOMATED Q-LINE CIRCUIT BREAKER
ABSTRACT OF THE DISCLOSURE
A fully automated residential-type circuit breaker assembly is made possible by the provision of retaining slots and guide channels formed within the breaker case. The breaker case then serves as an assembly fixture for specially designed armatures and magnets used within the trip section of the breaker as well as for a special designed bi-metallic trip element. A high calibration yield is accomplished by means of a low friction latch assembly.
ABSTRACT OF THE DISCLOSURE
A fully automated residential-type circuit breaker assembly is made possible by the provision of retaining slots and guide channels formed within the breaker case. The breaker case then serves as an assembly fixture for specially designed armatures and magnets used within the trip section of the breaker as well as for a special designed bi-metallic trip element. A high calibration yield is accomplished by means of a low friction latch assembly.
Description
~s~
l ~lPC-6286 AUTOMATED ~-LINE CIRCUIT BREAKER
B~_ GROUND OF THE INVENTION
U.S. Pa-tent 3,464,040 to David B. Powell issued August 26, 1969 discloses a compact circuit breaker construction for manufact~lring one-half inch residential "Q" type circuit breakers. The circuit breaker components are designed for fabrication on mass production equipment an~ are economically obtained.
The assembLy of the individual components during the manufacturing process entails some time to assure that the components are interconnected in the proper manner.
Further time is required to individually calibrate each breaker to determine whether the breaker trips within a prescribed time interval for a fixed test current~
Should a breaker fail to trip within the prescribed ~ime limit, the breaker must be set aside for later calibration. A detailed understanding of the compact breaker componentscan be obtained by referring to the Powell patent.
The purpose of the present invention is to provide a residential circuit breaker of economic design which can be completely assembled and tested for calibration in an automated assembly process.
:
,A
~2'~ lPC-6286 sur~M~R~ OF r IE''~N~_TION
~ residential circuit breaker design for fully automated assembly utilizes a modified molded case with guide channels and retaining slots Eormed -therein so that the case serves as an'assembly fixture to facilitate the automated assembly process. .An L-sha~ed ma~ne-t and armature assembly, closed loop mechanism spring, and a modified bi-metal trip element allow the breaker components to be robotically assembled within the case guides, channels and retaining slots~
BRIEF D~SCRIPTION OF THE DRAWINGS
Figure 1 is a plan view of the case used with the automated circuit breaker according to the invention;
Figure 2 is a front perspective view of the trip unit and terminal assembly used within the automated circuit breaker of the invention;
Figure 3 is a front perspective view of the magnetic assembly including the armature and magnet core used within the automated circuit breaker of the nventlon;
Figure 4 is a front perspective view of the cradle used within the automated circuit brea~er of the invention;' Figure 5 is a front perspective view of the ; mechanism spring used within the automated circuit breaker of the invention;
Figure 6 is a plan view of the cover used with the automated circuit breaker of the invention;
3Q Figure 7 is a top perspective view in isometric projection of the components used within the automated circuit breaker of the invention arranged in their order of assembly; and Figure 8 is a plan view of an assembled compact circuit breaker according to the invention.
~22~iqL20 DF.SCRIPrION OF r~lE PREEERR~.D EMBODIM N':r The automated circuit breaker case 10, havlny the retaining slots and gu:ide channels formed Eor provldiny a Ei.xture ~or the robotic assembly of the breaker components is depic-ted in E'igure 1. The case consists of a raised top rail 11, bottom rail 12, rear rail 13 and front rail 14. A handle recess 15 similar -to tha-t disclosed wi-thin the aforemen-tioned Powell patent is formed within the case along with a plurality of screw or rivet passages 7. A latch spring re-taining slot 16 is formed subjacent top rail 11 along with a calibration screw slot 1. A -trip assembly re-tainer slot 17 is formed between a right barrier 18 as best seen in Figure 8 and left barrier 19 extending upwards from the case and a terminal lug channel 6A is defi.ned by the bottom of the left barrier 19 and a por-tion of the angled arc barrier 23. ~he trip assembly retainer slot includes a pair of bosses 85 extending from left barrier 19 and an opposing abutment 86 on right barrier 18. An arc vent channel 29A is defined between the bo-ttom of the arc barrier and the bottom rail of the case. A magne-t s-top 3 is in-tegrally formed on a top portion of the angled arc barrier 23 and serves to check the forward motion of the magnet in a manner similar to that described within the Powell patent. A terminal slot 25 is defined between a terminal barrier 24 and a bottom portion of rear rail 13. The cradle, which will be described in detail below, is supported by a raised cradle bearing pivot 26 in combination with a cradle pedestal wall 27. A braid wire and contact blade channel generally indicated at 22 is formed between left and right barriers 20, 21.
A specially designed trip unit and terminal assembly 30 is sown in ~igure 2 and consists of a lug 1~2~
~ 4 - 41PC 62~6 terminal 31 carrying a binding screw 32 and attached -to a bi-metal strip 36 hy means oE an angled connecting strap 33 which is attached to the bi-metal by means of weld 34. The contact blade 38 which includes a yoke end 39A and a raised offset contact end 39B, and contact 40, is at-tached to a braided conductor 37 by means of weld 34 at one end and to a conductor 35by means of a weld 34 at an opposite end. ~ handle cooperating tab 91 is formed from the contact blade at the yoke end to engage within a slot 89 formed within the handle 5 as best seen in Figure 7. The braid conductor 37 is guided between a pair of tabs 84 extending from the contact blade proximate the weld. This is to constrain the braid from flexing at the weld and to prevent the braid from fra~ing during blade movement. The conductor 35 is attached to the bi-metal by a weld 34 to complete the assembly. A mechanism spring tab 41 extends from the offset contact end 39B. The trip unit and terminal assembly 30 is retained within case 10 of Figure 1 by inserting the angled connecting terminal strap 33 within the retainer slot 17 which positions the wire lug 31 within terminal lug chamber 6A and positions contact blade 38 and braid conductor 37 within the braid conductor and contact blade channel 22.
The magnet assembly 42 is shown in Figure 3 and con~ains an armature 44 and a magnet core 43. The armature is formed from a single piece of steel and is shaped to provide a pair of tabs 46 which abut the common side wall 9 of calibration screw slot 1 and latch spring slot 16 within the case shown in Figure 1 and a latch spring boss 52 r shown in Figure 8, which abuts the latch spring slot 16 when the magnet assembly is inserted within the case. The armature contains a narrow top piece 51, a flat bottom piece 49 and angled bottom piece 53 for promoting magnetic transfer between the armature and the magnet ~225~
41PC~6286 core ~3 A ~ shelf ~8, Eormed onto the armature, xeceives ancl supports a hook extension ~7 Eormed on-to -the magne-t core and assists in maintaining the correct separation distance between the armature and the magne-t core~ An angled top piece 45 on the magnet core assists in supporting the core within the case and also provides a pivot :eor the magnet core. An angled bottom piece 5~ on the rnagnet core cooperates with the flat bottom piece 49 and anyled bottom piece 53 on the armature to provide a closed magnetic loop which increases the magnetic coupling between the armature and the magnet core. The boss 55 formed on the bottom of the magnet core sets the spacing between the magnet core and the bi-metal 36, shown in Figure 2, when the magnet assembly is arranged around the bi-metal. The location of the hook extension is important for two reasons. The first purpose of the hook extension 47 is to provide a mechanical coupling between the bi-metal 36 and the armature 44 to cause the armature to move during thermal tripping when the bi-metal contacts boss 55 at the bottom of the magnet 43.
This forces the hook extension and the armature to move in unison away from the cradle 56 shown in Figure 4 during the thermal trip operation. The locatio~ of the hook extens.ion proximate the center o~ the magnet ~3 provides close mechanical couplin~ of the magnet to the armature to allow rapid movement of the armature during the thermal trip operation. However, since the hook extension is ~art of the magnet core, some magnetic coupling occurs between the hook extension and the armature on the side opposite the angled bottom piece 54.
. substantially reduces the adverse magnetic effect caused by the hook extensicn since the closer the hook extension is to the pivotal top angled piece, the less the mechanical advantage to oppose the motion of-the armature toward the magnet core during the magnetic trip operationr ~s~
~.PC-6286 The provision o:E L-~shaped magnet core ~3 and L shaped armature ~ allows ~emagnet assernbly 42 ~o be inserted l'downwardly", that is, with the case 10 of Figure 1 in the horiæontal plane. This was not possible with the magnet assembly described within the Po~ell patent since the "U-shaped" cross-section therein does not allow for downward assembly of the armature and core about the trip unit~ The latch opening 50 formed in the flat bottom piece 49 o~ the armature supports the cradle latch portion 63 formed at the end of ths cradle 56 shown in Figure 4. The hi~hly polished stainless steel inser-t 81 at the bottom of latch opening 50 minimizes friction between the cradle latch portion and the armature and permits the cradle latch portion to smoothly slide away from the latch opening when the armature is magnetically attracted to the magnet core during high overcurrent operation or during thermal trip when the bi-metal coupled through the magnet hook moves the armature ~4 and latch opening 50 away from the cradle latch portion 63. The consistent performance of the polished insert greatly increases the efficiency of the assembly and calibration process. The cradle is formed from a generally U-shaped body portion 60 having a slotted opening 62. The handle tab 61 and the weld break tab 64 pro~ide similar ~unctions as described for the cradle disclosed ~ithin the Powell patent.
mechanism sprin~ tab 59 cooperates with the mechanism spring tab 41 on the contact blade 38 shown in Figure 2 to support the mechanism spring 65 shown in Figure 5O To provide a simple and exact method for supporting the cradle pi~otally within the case, a circular end member 57 is formed at the end of the U-shaped body 60 opposite the latch portion 63. An opening 58 within the circular end member encompasses the raised cradle bearing pivot 26 formed within the case 10 shown in Figure 1 and the 41PC-62~6 outside perimeter of the circular end member 57 nes-ts between the raised cradle bear.ing pivot 26 and the cradle pedestal wall 27 to provide further support to the cradle while pivoting~ The mechanism spring 65 shown in Figure 5 is designed to consist of a body member 66 and à top eye 69 separated a fixed clistance by means of a leg extension 67 which engages the mechanism spring tab on the cradle shown in Figure 4 and a bottom eye 68 for engaging the mechanism spring tab 41 on the contact blade 38 shown in Figure 2. The provision of top and bottom spring eyes 69, 68 allows the mechanism spring tab 41 on the contact blade and the mechanism spring tab 59 on the cradle to be rapidly engaged by the robot since the robot ~Ifingers~ can be inserted within the spring eyes to slightly extend the spring body 66 before dropping the spring eyes 69, 68 over the mechanism spxing tabs 41, 59 ~ and withdrawing the robot fingers allowing the tabs to pick up the spring tension exerted by the extension oE the spring body, The closed looped eyes provide tangle free springs during part feed to the ro~ot. It was determined that efficient robotic assembly could ~e achieved by using circular configurations on the circuit breaker components such as the circular end member 57 Of the cradle and the spring eyes 69, 68 for engaging with upright extending projections such as the raised cradle retaining pivot 26 on the breaker case in Figure 1 and-the mechanism spring tabs 41, 59 ~epicted in Figures 2 and 4.
As described earlier, the confi~uration of the trip unit and terminal assembly 3~r magnetic assembly 42, cradle 56 and spring 65 shown in Figures 2-5 are configured for cooperating with the respective slots foxmed within th.e case depicted i.n Figure 1 for ease in robotic assembly. Also important in the assembly process 35 is the order in which the circuit breaker components are ~l~J25~
~lPC-6~6 assembled within the case. This order of assembly is shown in Figure 7 as follows. The case 10 is positioned in the horizontal plane such that the aforementioned slots are vertically accessible. The armature 44 is assembled first by dropping -the armature within the case and orienting the tabs 46 within one edge of the latch spriny ~lot 16 and orienting latch opening 50 in the vertical plane. The trip unit and terminal assembly 30 is assembled next by positioniny the trip assembly connecting strap 33 within the trip assembly conhec-ting strap retainer slot 17 such that the terminal l~g 31 sits within the terminal lug slot 6A and the contact blade 38 and flexible braid conductor 37 rests within channel 22. The magnec core 43 is then assembled by inserting the angled top piece 45 within the latch spring slot 16 proximate the armature tabs 46 and arranging the angled bottom piece 54 with the ; bottom piece 49 and angled piece 53 o the armature in a box-like configuration around the trip unit and terminal assembly bi-me-tal 36. Next, the handle 5 is positioned within the handle recess 15 formed within the case and the cradle 56 is assembled by arranging the cradle circular end member 57 around the raised cradle bearing pivot 26. The handle 5 includes flat portions 87, 88 on either side ~or carrying indicia as to the "on"
or loffl' statu~ o the breaker. One portion, such as 87, is color coded red to expose the red color when the handle is in an "on" position, while the other portion 88 ; is color coded white to expose the white color when the handle is in an "off" position. The mechanism spring 65 is assembled by attachin~ the spring eye 69 to the cradle spring tab 59 and attaching the mechanism spring eye 68 to the contact blade tab 41. The latch spring 4 is inserted wit~in latch spring slot 16 and engages the latch spring boss 52 on axmature 44. The terminal stab ~2'~ lPC~6286 _ 9 _ assembly 3 is fitted within terminal slot 25 and the terminal stab .spring 80 is positioned as indicated in Figure 8. A pocke~ channel 82 holds the arc chute 28 trapped between the case and the cover. The calibration S screw assembly 2 is press-fit within the calibration screw slot 1, cover 70 is placed over the complete assembly and screws or rivets 83 are applied to fasten the cover to the case~
The assembled compact breaker 76 can be seen by re~erring to Figure 8 wherein the cover is removed to expose the assembled components, all of which are tightly engaged wlthin the case 10 such that the.
completed brea~er 76 can be moved without disturbing the placement o any other components. This is an lS important Eeature required or robotic assembly since the breaker case and components are.often transported on moving conveyor systems during the assembly process before the cover is placed over the case and riveted thereto. In the completed brea]cer depicted in Figure 8, the terminal stab assembly 3j stab 79, spring 80 and fixed contact 77 are shown arranged within slot 25. The arc chute ~8 is'~hown located within the arc chute channel 82 intermediate the fixed and movable contacts 77, 40. Also shown is the cradle 56 supportably'mounted by means of the circular end 57 encompassing the cradle bearing pi~ot 26. The mechanism spring 65 is supported by means of the spring tab 41 on the contact blade 38 and the spring tab 59 on cradle 56. The arrangement o~
the latch sprin~ 4, armature tabs 46 and ma~net core top piece 45 are depicted within latch spring slot 16. The trip assembly connecting strap 33 is shown within retainer slot 17 and the terminal lug 31 is shown within the ~ermina'l lu~ channel 6A. The offset bosses 85 cooperate with abutment 86 to capture the strap 33 in a r~~
5~
~lPC-62~6 press:Eit relation to lockingly hold the trip unit 30 in place during furthe.r assembly of the breaker components. Th.is is an important feature oE the invention since no other :Eastening means is requirecl~
l ~lPC-6286 AUTOMATED ~-LINE CIRCUIT BREAKER
B~_ GROUND OF THE INVENTION
U.S. Pa-tent 3,464,040 to David B. Powell issued August 26, 1969 discloses a compact circuit breaker construction for manufact~lring one-half inch residential "Q" type circuit breakers. The circuit breaker components are designed for fabrication on mass production equipment an~ are economically obtained.
The assembLy of the individual components during the manufacturing process entails some time to assure that the components are interconnected in the proper manner.
Further time is required to individually calibrate each breaker to determine whether the breaker trips within a prescribed time interval for a fixed test current~
Should a breaker fail to trip within the prescribed ~ime limit, the breaker must be set aside for later calibration. A detailed understanding of the compact breaker componentscan be obtained by referring to the Powell patent.
The purpose of the present invention is to provide a residential circuit breaker of economic design which can be completely assembled and tested for calibration in an automated assembly process.
:
,A
~2'~ lPC-6286 sur~M~R~ OF r IE''~N~_TION
~ residential circuit breaker design for fully automated assembly utilizes a modified molded case with guide channels and retaining slots Eormed -therein so that the case serves as an'assembly fixture to facilitate the automated assembly process. .An L-sha~ed ma~ne-t and armature assembly, closed loop mechanism spring, and a modified bi-metal trip element allow the breaker components to be robotically assembled within the case guides, channels and retaining slots~
BRIEF D~SCRIPTION OF THE DRAWINGS
Figure 1 is a plan view of the case used with the automated circuit breaker according to the invention;
Figure 2 is a front perspective view of the trip unit and terminal assembly used within the automated circuit breaker of the invention;
Figure 3 is a front perspective view of the magnetic assembly including the armature and magnet core used within the automated circuit breaker of the nventlon;
Figure 4 is a front perspective view of the cradle used within the automated circuit brea~er of the invention;' Figure 5 is a front perspective view of the ; mechanism spring used within the automated circuit breaker of the invention;
Figure 6 is a plan view of the cover used with the automated circuit breaker of the invention;
3Q Figure 7 is a top perspective view in isometric projection of the components used within the automated circuit breaker of the invention arranged in their order of assembly; and Figure 8 is a plan view of an assembled compact circuit breaker according to the invention.
~22~iqL20 DF.SCRIPrION OF r~lE PREEERR~.D EMBODIM N':r The automated circuit breaker case 10, havlny the retaining slots and gu:ide channels formed Eor provldiny a Ei.xture ~or the robotic assembly of the breaker components is depic-ted in E'igure 1. The case consists of a raised top rail 11, bottom rail 12, rear rail 13 and front rail 14. A handle recess 15 similar -to tha-t disclosed wi-thin the aforemen-tioned Powell patent is formed within the case along with a plurality of screw or rivet passages 7. A latch spring re-taining slot 16 is formed subjacent top rail 11 along with a calibration screw slot 1. A -trip assembly re-tainer slot 17 is formed between a right barrier 18 as best seen in Figure 8 and left barrier 19 extending upwards from the case and a terminal lug channel 6A is defi.ned by the bottom of the left barrier 19 and a por-tion of the angled arc barrier 23. ~he trip assembly retainer slot includes a pair of bosses 85 extending from left barrier 19 and an opposing abutment 86 on right barrier 18. An arc vent channel 29A is defined between the bo-ttom of the arc barrier and the bottom rail of the case. A magne-t s-top 3 is in-tegrally formed on a top portion of the angled arc barrier 23 and serves to check the forward motion of the magnet in a manner similar to that described within the Powell patent. A terminal slot 25 is defined between a terminal barrier 24 and a bottom portion of rear rail 13. The cradle, which will be described in detail below, is supported by a raised cradle bearing pivot 26 in combination with a cradle pedestal wall 27. A braid wire and contact blade channel generally indicated at 22 is formed between left and right barriers 20, 21.
A specially designed trip unit and terminal assembly 30 is sown in ~igure 2 and consists of a lug 1~2~
~ 4 - 41PC 62~6 terminal 31 carrying a binding screw 32 and attached -to a bi-metal strip 36 hy means oE an angled connecting strap 33 which is attached to the bi-metal by means of weld 34. The contact blade 38 which includes a yoke end 39A and a raised offset contact end 39B, and contact 40, is at-tached to a braided conductor 37 by means of weld 34 at one end and to a conductor 35by means of a weld 34 at an opposite end. ~ handle cooperating tab 91 is formed from the contact blade at the yoke end to engage within a slot 89 formed within the handle 5 as best seen in Figure 7. The braid conductor 37 is guided between a pair of tabs 84 extending from the contact blade proximate the weld. This is to constrain the braid from flexing at the weld and to prevent the braid from fra~ing during blade movement. The conductor 35 is attached to the bi-metal by a weld 34 to complete the assembly. A mechanism spring tab 41 extends from the offset contact end 39B. The trip unit and terminal assembly 30 is retained within case 10 of Figure 1 by inserting the angled connecting terminal strap 33 within the retainer slot 17 which positions the wire lug 31 within terminal lug chamber 6A and positions contact blade 38 and braid conductor 37 within the braid conductor and contact blade channel 22.
The magnet assembly 42 is shown in Figure 3 and con~ains an armature 44 and a magnet core 43. The armature is formed from a single piece of steel and is shaped to provide a pair of tabs 46 which abut the common side wall 9 of calibration screw slot 1 and latch spring slot 16 within the case shown in Figure 1 and a latch spring boss 52 r shown in Figure 8, which abuts the latch spring slot 16 when the magnet assembly is inserted within the case. The armature contains a narrow top piece 51, a flat bottom piece 49 and angled bottom piece 53 for promoting magnetic transfer between the armature and the magnet ~225~
41PC~6286 core ~3 A ~ shelf ~8, Eormed onto the armature, xeceives ancl supports a hook extension ~7 Eormed on-to -the magne-t core and assists in maintaining the correct separation distance between the armature and the magne-t core~ An angled top piece 45 on the magnet core assists in supporting the core within the case and also provides a pivot :eor the magnet core. An angled bottom piece 5~ on the rnagnet core cooperates with the flat bottom piece 49 and anyled bottom piece 53 on the armature to provide a closed magnetic loop which increases the magnetic coupling between the armature and the magnet core. The boss 55 formed on the bottom of the magnet core sets the spacing between the magnet core and the bi-metal 36, shown in Figure 2, when the magnet assembly is arranged around the bi-metal. The location of the hook extension is important for two reasons. The first purpose of the hook extension 47 is to provide a mechanical coupling between the bi-metal 36 and the armature 44 to cause the armature to move during thermal tripping when the bi-metal contacts boss 55 at the bottom of the magnet 43.
This forces the hook extension and the armature to move in unison away from the cradle 56 shown in Figure 4 during the thermal trip operation. The locatio~ of the hook extens.ion proximate the center o~ the magnet ~3 provides close mechanical couplin~ of the magnet to the armature to allow rapid movement of the armature during the thermal trip operation. However, since the hook extension is ~art of the magnet core, some magnetic coupling occurs between the hook extension and the armature on the side opposite the angled bottom piece 54.
. substantially reduces the adverse magnetic effect caused by the hook extensicn since the closer the hook extension is to the pivotal top angled piece, the less the mechanical advantage to oppose the motion of-the armature toward the magnet core during the magnetic trip operationr ~s~
~.PC-6286 The provision o:E L-~shaped magnet core ~3 and L shaped armature ~ allows ~emagnet assernbly 42 ~o be inserted l'downwardly", that is, with the case 10 of Figure 1 in the horiæontal plane. This was not possible with the magnet assembly described within the Po~ell patent since the "U-shaped" cross-section therein does not allow for downward assembly of the armature and core about the trip unit~ The latch opening 50 formed in the flat bottom piece 49 o~ the armature supports the cradle latch portion 63 formed at the end of ths cradle 56 shown in Figure 4. The hi~hly polished stainless steel inser-t 81 at the bottom of latch opening 50 minimizes friction between the cradle latch portion and the armature and permits the cradle latch portion to smoothly slide away from the latch opening when the armature is magnetically attracted to the magnet core during high overcurrent operation or during thermal trip when the bi-metal coupled through the magnet hook moves the armature ~4 and latch opening 50 away from the cradle latch portion 63. The consistent performance of the polished insert greatly increases the efficiency of the assembly and calibration process. The cradle is formed from a generally U-shaped body portion 60 having a slotted opening 62. The handle tab 61 and the weld break tab 64 pro~ide similar ~unctions as described for the cradle disclosed ~ithin the Powell patent.
mechanism sprin~ tab 59 cooperates with the mechanism spring tab 41 on the contact blade 38 shown in Figure 2 to support the mechanism spring 65 shown in Figure 5O To provide a simple and exact method for supporting the cradle pi~otally within the case, a circular end member 57 is formed at the end of the U-shaped body 60 opposite the latch portion 63. An opening 58 within the circular end member encompasses the raised cradle bearing pivot 26 formed within the case 10 shown in Figure 1 and the 41PC-62~6 outside perimeter of the circular end member 57 nes-ts between the raised cradle bear.ing pivot 26 and the cradle pedestal wall 27 to provide further support to the cradle while pivoting~ The mechanism spring 65 shown in Figure 5 is designed to consist of a body member 66 and à top eye 69 separated a fixed clistance by means of a leg extension 67 which engages the mechanism spring tab on the cradle shown in Figure 4 and a bottom eye 68 for engaging the mechanism spring tab 41 on the contact blade 38 shown in Figure 2. The provision of top and bottom spring eyes 69, 68 allows the mechanism spring tab 41 on the contact blade and the mechanism spring tab 59 on the cradle to be rapidly engaged by the robot since the robot ~Ifingers~ can be inserted within the spring eyes to slightly extend the spring body 66 before dropping the spring eyes 69, 68 over the mechanism spxing tabs 41, 59 ~ and withdrawing the robot fingers allowing the tabs to pick up the spring tension exerted by the extension oE the spring body, The closed looped eyes provide tangle free springs during part feed to the ro~ot. It was determined that efficient robotic assembly could ~e achieved by using circular configurations on the circuit breaker components such as the circular end member 57 Of the cradle and the spring eyes 69, 68 for engaging with upright extending projections such as the raised cradle retaining pivot 26 on the breaker case in Figure 1 and-the mechanism spring tabs 41, 59 ~epicted in Figures 2 and 4.
As described earlier, the confi~uration of the trip unit and terminal assembly 3~r magnetic assembly 42, cradle 56 and spring 65 shown in Figures 2-5 are configured for cooperating with the respective slots foxmed within th.e case depicted i.n Figure 1 for ease in robotic assembly. Also important in the assembly process 35 is the order in which the circuit breaker components are ~l~J25~
~lPC-6~6 assembled within the case. This order of assembly is shown in Figure 7 as follows. The case 10 is positioned in the horizontal plane such that the aforementioned slots are vertically accessible. The armature 44 is assembled first by dropping -the armature within the case and orienting the tabs 46 within one edge of the latch spriny ~lot 16 and orienting latch opening 50 in the vertical plane. The trip unit and terminal assembly 30 is assembled next by positioniny the trip assembly connecting strap 33 within the trip assembly conhec-ting strap retainer slot 17 such that the terminal l~g 31 sits within the terminal lug slot 6A and the contact blade 38 and flexible braid conductor 37 rests within channel 22. The magnec core 43 is then assembled by inserting the angled top piece 45 within the latch spring slot 16 proximate the armature tabs 46 and arranging the angled bottom piece 54 with the ; bottom piece 49 and angled piece 53 o the armature in a box-like configuration around the trip unit and terminal assembly bi-me-tal 36. Next, the handle 5 is positioned within the handle recess 15 formed within the case and the cradle 56 is assembled by arranging the cradle circular end member 57 around the raised cradle bearing pivot 26. The handle 5 includes flat portions 87, 88 on either side ~or carrying indicia as to the "on"
or loffl' statu~ o the breaker. One portion, such as 87, is color coded red to expose the red color when the handle is in an "on" position, while the other portion 88 ; is color coded white to expose the white color when the handle is in an "off" position. The mechanism spring 65 is assembled by attachin~ the spring eye 69 to the cradle spring tab 59 and attaching the mechanism spring eye 68 to the contact blade tab 41. The latch spring 4 is inserted wit~in latch spring slot 16 and engages the latch spring boss 52 on axmature 44. The terminal stab ~2'~ lPC~6286 _ 9 _ assembly 3 is fitted within terminal slot 25 and the terminal stab .spring 80 is positioned as indicated in Figure 8. A pocke~ channel 82 holds the arc chute 28 trapped between the case and the cover. The calibration S screw assembly 2 is press-fit within the calibration screw slot 1, cover 70 is placed over the complete assembly and screws or rivets 83 are applied to fasten the cover to the case~
The assembled compact breaker 76 can be seen by re~erring to Figure 8 wherein the cover is removed to expose the assembled components, all of which are tightly engaged wlthin the case 10 such that the.
completed brea~er 76 can be moved without disturbing the placement o any other components. This is an lS important Eeature required or robotic assembly since the breaker case and components are.often transported on moving conveyor systems during the assembly process before the cover is placed over the case and riveted thereto. In the completed brea]cer depicted in Figure 8, the terminal stab assembly 3j stab 79, spring 80 and fixed contact 77 are shown arranged within slot 25. The arc chute ~8 is'~hown located within the arc chute channel 82 intermediate the fixed and movable contacts 77, 40. Also shown is the cradle 56 supportably'mounted by means of the circular end 57 encompassing the cradle bearing pi~ot 26. The mechanism spring 65 is supported by means of the spring tab 41 on the contact blade 38 and the spring tab 59 on cradle 56. The arrangement o~
the latch sprin~ 4, armature tabs 46 and ma~net core top piece 45 are depicted within latch spring slot 16. The trip assembly connecting strap 33 is shown within retainer slot 17 and the terminal lug 31 is shown within the ~ermina'l lu~ channel 6A. The offset bosses 85 cooperate with abutment 86 to capture the strap 33 in a r~~
5~
~lPC-62~6 press:Eit relation to lockingly hold the trip unit 30 in place during furthe.r assembly of the breaker components. Th.is is an important feature oE the invention since no other :Eastening means is requirecl~
Claims (15)
1. An electric circuit breaker for fully automated assembly comprising:
a molded plastic case having a plurality of retaining slots and guide channels formed therein;
a trip unit and terminal assembly consisting of a lug terminal and bi-metal at one end and a contact blade having top and bottom ends at an opposite end jointed by means of a braided conductor;
a magnet assembly consisting of an armature and magnet core, said armature being formed from a single L-shaped metal piece having a narrow top piece and a wider angled bottom piece which includes a latch opening, said magnet core being formed from a single L-shaped metal piece having a top angled piece for providing a pivot to said core, a bottom angled piece and a hook extension for engaging said armature bottom piece which forms a closed magnetic loop in cooperation with said armature bottom piece;
a cradle formed from a U-shaped piece having a handle tab at a top for engaging a handle, a latch portion at an end of one leg of the U for releasably engaging said latch opening and a circular end member at an end of another leg of the U, said circular member pivotally supporting the cradle within said case; and a mechanism spring connecting between said cradle and said contact blade to bias a moveable contact on said contact blade into contact with a fixed contact supported on said case when an operating handle is in a closed position for providing current flow through said contacts and for rapidly separating said contacts when said trip unit releases said cradle latch portion from said latch opening upon excess current flow through said contacts.
a molded plastic case having a plurality of retaining slots and guide channels formed therein;
a trip unit and terminal assembly consisting of a lug terminal and bi-metal at one end and a contact blade having top and bottom ends at an opposite end jointed by means of a braided conductor;
a magnet assembly consisting of an armature and magnet core, said armature being formed from a single L-shaped metal piece having a narrow top piece and a wider angled bottom piece which includes a latch opening, said magnet core being formed from a single L-shaped metal piece having a top angled piece for providing a pivot to said core, a bottom angled piece and a hook extension for engaging said armature bottom piece which forms a closed magnetic loop in cooperation with said armature bottom piece;
a cradle formed from a U-shaped piece having a handle tab at a top for engaging a handle, a latch portion at an end of one leg of the U for releasably engaging said latch opening and a circular end member at an end of another leg of the U, said circular member pivotally supporting the cradle within said case; and a mechanism spring connecting between said cradle and said contact blade to bias a moveable contact on said contact blade into contact with a fixed contact supported on said case when an operating handle is in a closed position for providing current flow through said contacts and for rapidly separating said contacts when said trip unit releases said cradle latch portion from said latch opening upon excess current flow through said contacts.
2. The circuit breaker of claim 1 wherein said trip unit and terminal assembly, said cradle and said magnetic assembly are all retained within said retaining slots and guide channels formed within said case.
3. The circuit breaker of claim 2 including a plastic molded cover having a plurality of retaining slots and guide channels formed therein for cooperating with said case retaining slots and guide channels to hold said trip unit and terminal assembly and said cradle and magnetic assembly within said case.
4. The circuit breaker of claim 1 wherein said case includes a raised cradle retaining pivot for receiving said cradle circular member and pivotally supporting said cradle within said case.
5. The circuit breaker of claim 1 wherein said mechanism spring comprises a body member and a pair of closed loop eyes; one at either end of said body for encompassing and engaging a spring tab on said top of said cradle and a spring tab intermediate top and bottom edges of said contact blade.
6. The circuit breaker of claim 1 further including a polished steel insert at a bottom of said armature latch opening to slidingly engage said cradle latch portion and to allow frictionless movement of said cradle latch portion out of said latch opening.
7. The circuit breaker of claim 1 wherein said armature bottom piece includes a shelf portion for cooperating with said magnetic core hook extension to securely hold said magnetic core and armature in close magnetic relation.
8. The circuit breaker of claim 1 wherein said armature top piece further includes a pair of tabs for abutting and being supported by a sidewall formed within said case, said sidewall separating a calibration slot from a latch spring slot also formed within said case.
9. The circuit breaker of claim 8 wherein said armature top piece further includes a latch spring boss formed on said armature top piece for positioning and supporting a latch spring when said latch spring is inserted within said latch spring slot.
10. The circuit breaker of claim 1 including an arc chute positioned within an arc chute recess formed within said case proximate said fixed contact.
11. The circuit breaker of claim 1 wherein said braided conductor joins said contact blade between a pair of upright tabs on said contact blade for constraining said braid from flexing during movement of said contact blade.
12. The circuit breaker of claim 1 wherein said magnet core hook extension is intermediate said magnet core top angled piece and a bottom of said magnet core bottom angled piece to mechanically couple said bi-metal and said armature to minimize force opposed to motion of said armature upon magnetic tripping of the breaker.
13. The trip unit of claim 2 wherein said trip unit further includes an angled connector between said bi-metal and said terminal assembly located within one of said retaining slots, said one retaining slot containing a pair of bosses on one side and an abutment on an opposite side to lockingly hold said trip unit to said case.
14. The trip unit of claim 1 wherein said handle includes a pair of first and second flat surfaces each containing colored indicia whereby said first surface exposes a first color when said handle is in an ON
position and said second surface exposes a second color when said handle is in an OFF position.
15. A method for automatically assembling a circuit breaker assembly within a molded plastic circuit breaker case having a plurality of retaining slots and guide channels integrally formed within the case comprising the steps of:
inserting an armature containing a latch opening within a first one of said retaining slots within said case;
positioning a contact blade and trip unit assembly over said armature within said case;
inserting a magnetic core over said trip unit and said armature and positioning a hook extension on said magnetic core over a shelf portion on said armature;
positioning a handle member within a second one of said retaining slots within said case;
inserting a two legged U-shaped cradle member having a circular end member at an end of one of the legs and a latch portion at an end of the other of the legs and positioning the circular end member over a pivot formed within said case and positioning said latch portion in operative relation to said armature latch opening;
arranging a mechanism spring, having a closed loop eye at both ends, between said cradle and said contact blade by engaging one of said spring eyes over a spring tab on said contact blade and engaging the other of said spring eyes over a spring tab on said cradle;
inserting a latch spring within a third one of said retaining slots within said case proximate a top end of said armature;
positioning an arc chute and fixed contact within a fourth recess formed in said case in operational relationship with said contact blade; and
position and said second surface exposes a second color when said handle is in an OFF position.
15. A method for automatically assembling a circuit breaker assembly within a molded plastic circuit breaker case having a plurality of retaining slots and guide channels integrally formed within the case comprising the steps of:
inserting an armature containing a latch opening within a first one of said retaining slots within said case;
positioning a contact blade and trip unit assembly over said armature within said case;
inserting a magnetic core over said trip unit and said armature and positioning a hook extension on said magnetic core over a shelf portion on said armature;
positioning a handle member within a second one of said retaining slots within said case;
inserting a two legged U-shaped cradle member having a circular end member at an end of one of the legs and a latch portion at an end of the other of the legs and positioning the circular end member over a pivot formed within said case and positioning said latch portion in operative relation to said armature latch opening;
arranging a mechanism spring, having a closed loop eye at both ends, between said cradle and said contact blade by engaging one of said spring eyes over a spring tab on said contact blade and engaging the other of said spring eyes over a spring tab on said cradle;
inserting a latch spring within a third one of said retaining slots within said case proximate a top end of said armature;
positioning an arc chute and fixed contact within a fourth recess formed in said case in operational relationship with said contact blade; and
Claim 15 continued:
fastening a molded plastic cover having a corresponding plurality of slots formed therein over said case whereby said slots formed in said cover cooperate with said slots formed in said case to provide operational clearance for said circuit breaker assembly.
fastening a molded plastic cover having a corresponding plurality of slots formed therein over said case whereby said slots formed in said cover cooperate with said slots formed in said case to provide operational clearance for said circuit breaker assembly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000470743A CA1225420A (en) | 1984-12-20 | 1984-12-20 | Automated q-line circuit breaker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000470743A CA1225420A (en) | 1984-12-20 | 1984-12-20 | Automated q-line circuit breaker |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1225420A true CA1225420A (en) | 1987-08-11 |
Family
ID=4129425
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000470743A Expired CA1225420A (en) | 1984-12-20 | 1984-12-20 | Automated q-line circuit breaker |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1225420A (en) |
-
1984
- 1984-12-20 CA CA000470743A patent/CA1225420A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |