Abstract:
A circuit breaker is disclosed wherein two breakers are arranged in mirror image relation having their respective contacts facing each other and abutting alternately either a common contact carrier of U-shaped configurations while double contact is prevented mechanically. In an alternative version the stationary contacts are arranged for an axial operation change. The arrangement permits reduction in internal connections as well as in space requirement without loss in function as compared with known multiple circuit breaker units.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an electromagnetically operated circuit breaker for purposes of controlling electrical motors. The circuit breaker operating by axially shifting an actuator for purposes of opening and/or closing contact. 
     German printed patent application No. 2,622,054 discloses a circuit breaker of the type basically to which the invention pertains. Circuit breakers to be used for controlling electro motors are usually employed in the plurality so that several of them are placed side by side on a frame plate or the like and electrical conductors interconnect them to the extent such connection is needed. A known three phase arrangement includes for example two circuit breakers and seven conductors are needed to connect them to each other, to the motor and to the source of power supply. In the case of these circuit breakers twelve such conductors are needed. The installation of these connections is extensive because each individual connection has to be made seperately including cutting the conductors at a suitable length, removal of insulation therefrom bending and fastening. In order to avoid faulty connections and particularly in order to avoid short circuits in the case of a mechanical operation, one needs either a mechanical or an electrical latching system to avoid undesired electrical connections. Another disadvantage of the known circuit breakers is a relatively high space requirement and a large area of mounting. 
     DESCRIPTION OF THE INVENTION 
     It is an object of the present invention to provide a new and improved circuit breaker structure which is of a more compact design and easy to install under utilization of a simple latching mechanism avoiding erroneous connections. 
     It is another object of the present invention to provide new and improved arrangement for circuit breakers being constructed to facilitate installation under avoidance of connection errors and also constructed to avoid, by operation of the construction principals involved, incorrect operating states. 
     In accordance with the preferred embodiment of the present invention, it is suggested to provided circuit breaker in a twin arrangement with basically a mirror image arrangement of the circuit breakers involved and having the contacts generally arranged in a facing arrangement; there being a U-shaped stationary contact carrier interposed whose legs respectively cooperate with contact making circuit breaker members mounted to movable actuators including at least one armature of the two circuit breakers. In addition, a mechanical limit, lock or stop arrangement is provided cooperating in effect between the movable portions of each of the two circuit breakers to establishe a minimum distance between the contact carrying members so that with certainty only one of them can make contact with the contact on the stationary U-shaped contact carrier. 
     The mirror image arrangement establishes in fact a reduction of the overall mounting surface by a factor of two and in fact the volume occupied by this arrangement is reduced to 1/4 the value usually needed in the case of two circuit breakers. Moreover, the number of external circuit connections needed is reduced from seven to four in the case of a three-phase circuit breaker. In other cases the number of connecting wires is even reduced from 12 to 7. The contact making devices are configured differently as compared with the conventional construction and the mirror image arrangement of two circuit breakers establishes in effect a very easy manner for the incorporation of a blocking device because the end of the circuit breakers per se prevent interconnection between them simply on account of the mirror image arrangement. 
     A circuit connection is made, for example, near the bottom of the U of the above mentioned stationary contact carrier, and the legs of the U are positioned in general alignment preferably in horizontal alignment with flat, contact carrying elements individually to be connected with the U-shaped contact carrier by means of the respective contact making and circuit breaker members of the two circuit breakers. These additional flat contact elements are preferably differently constructed in that one of them at least has a crimped portion while the other is generally flat so that circuit connections to them can be made with relative ease. 
     The entire arrangement is preferably provided in a case or housing which may be subdivided into sections and includes generally a tubularly configured protion in which are mounted sleeve or sleeve like elements respectively carrying the movable armature elements for the two circuit breakers while portions of the sleeve are provided with extensions which are amensable to abutment to thereby establish the promixity limitation mentioned above. The stationary elements of the respective circuit breakers are arranged also within the sleeves and are fixed for immobility particularly in axial direction. The movable magnetic elements (i.e. armatures) generally and the movable sleeves in which they are mounted in particular are spring-biased such that these two sleeve elements are urged permanently in directions of opposing displacement. The movable contact carrying members are mounted in the respective sleeve extensions and extend laterally therefrom; they are also spring biased and permit to a limited extent axial displacement of the respective member within its mounting sleeve extension. 
     In furtherance of the invention auxiliary contacts may be provided and associated with each of the circuit breaker being basically of the same construction and following the same construction principle involved in the principal contact making operations; however, instead of a common U-shaped contact carrier, individual crimped contact carriers are provided and mounted in transverse portions of the casing in such a manner that they can be selectively positioned for contact making or contact breaking upon energization of the principal magnetic arrangements depending on the use on intent to make of these auxiliary contacts. The movable contact members are provided in pairs, but only one at a time participate in the operation, depending on the orientation of the stationary contacts. 
     In furtherance of the invention, the principle can be employed also in conjunction with a single electromagnetic arrangement being constructed as aforedescribed while cooperating with a second contact carrying member mounted on a plate, but having also an extension cooperating, however with the sleeve like extension of the magnetically operated device in the above mentioned, proximity limiting manner. However, this construction principal is employed here for purposes of imparting actuation upon the second contact member, as there is only one electromagnetic actuator. 
     It can thus be seen that the invention is to be seen in a twin arrangment of which one at least includes a movable armature element with a sleeve and a contact carrying member projecting from a sleeve extension and functioning as a mechanical actuator. When cooperating with an arrangement of a similar kind these magnetic actuators may engage mutually in order to provide proximity limiting for the two contact carrying members as they cooperate with a stationary U-shaped contact carrier and are to be kept apart at a distance larger than the spacing between the legs of the U. An alternative version includes just the proximity control extension with one contact carrying member and an overall spring bias whereby, however, the proximity control also functions as a control for opposing mode like actuation of the two sets of contacts, therefore, a plurality of different uses and connections can be provided for in which one part (i.e., one circuit breaker) is always the same, but different supplemental portions including the above mentioned auxiliary contact arrangement can be provided which involves basically very slightly different constructions of the casing housing the electrical operating parts. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal section view through a twin circuit breaker in accordance with the preferred embodiment of the present invention for practicing the best mode thereof; 
     FIG. 2 illustrates a section taken along the lines II--II through FIG. 1; 
     FIGS. 3, 4 and 5 are circuit diagrams illustrating and demonstrating the savings in connection and incurred upon using a twin circuit breaker in accordance with the preferred embodiment; 
     FIGS. 3a, 4a, 5a, 6a and 6 illustrate schematically the saving of space resulting from the construction as to FIGS. 1 and 2; 
     FIG. 7 is a cross-section as indicated in FIG. 2; 
     FIG. 8 is a section on an enlarged scale as indicated in FIG. 7; 
     FIG. 9 is a view of the detail of FIG. 8 as indicated by arrow A therein; and 
     FIG. 10 is a sectional view through another embodiment of the invention. 
    
    
     Proceeding now to the detailed description of the drawings, FIG. 1 illustrates the mirror image arrangement of two circuit breakers A and B within a common case or housing 20, the arrangement being mounted to a frame plate 24. A U-shaped contact carrier 11 is disposed between the two circuit breakers A and B; particularly the device 11 is mounted on a transverse element 21 of the housing 20. The contact carrier 11 includes a bottom, as far as the &#34;U&#34; is concerned, being denoted by reference numeral 11c; legs 11b and 11a extend from that bottom bar in horizontal direction. 
     A contact 12 is connected to the contact member 11 in the vicinity of the bottom bar 11c. Another contact carrier 13a is provided in alignment with the leg 11a and a contact carrier 13b is provided in alignment with the leg 11b. Two contact carriers 13a and 13b are respectively connected to connections, 12a and 12b, whereby the connection 12a for the circuit breaker A is connected to the respective contact 13a by means of a crimping 14 in the latter. The contact carrier 11 and the contact carriers 13a and b are provided with contacts proper 18a and b. These contacts cooperate with contacts such as 28a on a movable operating contact carrier, circuit breaker member 10a for the circuit breaker A and contacts 28b on a movable carrier member 10b for the circuit breaker B. These operating contact making and circuit breaker members such as 10b are run through slots 7 of sleeve like extensions such as 6b extending from an armature carrying sleeves such as 4, for circuit breaker B, there is a similar, movable arrangement provided for circuit breaker A, including a sleeve extension 6a. 
     Each of the armature sleeves 4 is axially displacably mounted and guided in a tubular guide portion 23 of the housing 20. Each armature sleeve 4 extends around a stationary magnet 1 and is connected to a movable magnet 2, there being a coil 3 interposed between the two magnets. The respective coil is held on transverse plates 22 of the housing 20. These elements are identified with the stated reference numerals with regard to the circuit breaker B, but one can readily see from the bottom portion of FIG. 1 that an analogous electromagnetic arrangement is provided for the circuit breaker A. 
     The armature sleeve 4 has a bottom 5 from which the sleeve extension 6 projects. This extension is provided with the contact slots 7 as stated, but is also provided with a contact pressure slot 8 for receiving a plate 15 against which bears a spring 9. This spring 9 acts upon a loop element 17 of a cooling plate 16 against which bears the contact carrier member 10b. This is particularly visible in FIG. 2. The contact pressure slot 8 extends for about the half of the length of the spring 9. 
     In the arrangement shown in FIGS. 1 and 2, the contact of circuit breaker A are closed and those of the circuit breaker B are open, in other words the contacts 28b on the contact carrier and circuit breaker member 10a bear against the contacts 18a of carrier 13a and leg 11a while the contacts 18b are disengaged from the contacts 28b on the contact carrier and member 10b. One can see a small air gap between the two sleeve extensions 6a and 6b respectively pertaining to circuit breakers A and B and particularly well visible is the accessability to the contact connection 12a and 12b. FIG. 2 shows also, that for a three phase arrangement, three contact making and circuit breaker members per circuit breaker operate in parallel. 
     Springs 25 are provided for returning the respective movable magnets 2 to an initial position. These springs are particularly shown in FIG. 1. This means that in the case the respective energizing coil such as 3 is not energized, i.e., does not carry any current, the respective spring 25 causes the respective movable magnet 2 to return to an initial condition so that the respective movable contact carrier in the respective sleeve extension 6a or 6b causes its contacts to open. This is actually the operating state for the circuit breaker B. It has to be emphasized, however, that the energization of the circuit breakers A and B is completely independent from each other, in other words these two circuit breakers do not operate in opposing modes or at least they are not designed to compel them for alternating contact making operations though of course, the electrical control and operation may in fact in a specific situation cause them to operate in that manner, however, basically they are provided for independent operation in which each of these circuit breakers can have open or closed contacts, irrespective of the contact making and breaking state of the respective other circuit breaker. 
     FIG. 3a illustrate schematically in side and top elevations the space and mounting requirements for the circuit breaker arrangement of FIGS. 1 and 2. FIG. 3 illustrates correspondingly the electric circuit connection. Herein, reference numeral 19 refers to those four external electrical connections that have to be made when the two circuit breakers A and B are to be used for controlling a motor. The connections 11&#39; are actually provided by the three U-shaped elements such as 11. In a conventional circuit breaker arrangement the additional circuit connections 11&#39; have to made also but in the present construction, these additional connections are not needed because they are internally provided by the construction of the twin circuit breaker arrangement. FIG. 4a illustrates the space and mounting requirements for two conventional circuit breakers placed side by side and the circuit connections needed for controlling a motor are shown in FIG. 4. It can readily be seen that altogether seven connections 19 have to be made and the mounting space is considerably larger. 
     In the case of FIG. 5, three circuit breakers are assumed. The two circuit breakers A and B are mounted as per the present invention and the third one denoted by character C is positioned next to the twin arrangement. FIG. 5 illustrates the circuit connection and again only some connections 19 have to be made and installed while the connections 11&#39; are inherent in the arrangement, particularly the construction of the twin circuit breaker A and B. 
     FIG. 6a illustrates analogously three separate circuit breakers and one can see that their space and volume requirement is higher. Moreover, FIG. 6 illustrates a circuit connections to be realized and one can see that altogether twelve connections 19 have to be completed vs. seven in FIG. 5. 
     Proceeding now to the description of FIG. 7, it can readily be seen that an auxiliary contact chambers 38 visible also in FIG. 2, provides space for a plurality of additional contacts. First of all, there is an upper pair of movable contact carriers 101 and 102, pertaining to circuit breaker B, but only one of these carriers operates at a time. Presently carrier 102 will cooperate with supplemental or auxiliary contacts 26b; they are provided in an upper chamber for purposes of accomodating closing of contacts on energization of breaker B while circuit breaking action is concurrently provided for in the lower part of the drawing. The auxiliary contact arrangement includes two movable carriers 103 and 104 of which only the latter used presently, cooperating with contacts on carrier 26A. 
     One could turn the auxiliary contact 26a and/or 26b around as indicated by dash dot line in FIG. 7 in which case the functioning of opening and closing in the upper and lower portions of the drawing of FIG. 7 would be reversed, and contack making and/or breaking action stiffs to the second carriers (102, 103) of each set. If the upper auxiliary contact 26b, for example were placed into the dash dot position then the contact carrier 102 will engage the turned around contacts 26b and will therefore be presented from assuming the somewhat higher position illustrated in this specific situation and for the particular position of the auxiliary contacts they actually have. The contact carriers such as are actuated together with the principal contacts as per FIGS. 1 and 2. 
     In other words, the magnetic arrangements in FIG. 7 are the same as in FIGS. 1 and 2. The auxiliary contacts 26a, b are provided with crimping being in turn provided with threaded bores for receiving the threaded shanks such as 36 of screws or bolts pertaining to contacts 112. Perforations 29 in the housing 20 are provided to run the auxiliary contacts 26 to the interior contact space proper denoted with reference numeral 30. The perforations 29 are particularly illustrated in FIG. 9 and they are provided with grooves 29a for insertion and clamping of the auxiliary contacts 26, (being 26a or 26b) such a contact is shown in position in FIG. 8, the arrow A illustrates the view of FIG. 9. 
     A sleeve 61a extends from below into the contact space 30 the sleeve 61a being connected to a movable magnet. This sleeve 61a has a slot 67a for receiving the two contacts 103 and 104 having contact such as 181. The two carrier elements 103 and 104 carry these contacts so that they face in opposite direction. These contact carriers 103 and 104 are forced by means of a contact spring 109 against the ends of the slot 67a. This particular construction was described with reference to the lower circuit breaker; the arrangement of the upper circuit breaker arrangement is analogously constructed. 
     FIG. 10 illustrates a longitudinal section through another circuit breaker in which the upper circuit breaker portion is provided with a a plate like actuating element 116 which is acted upon by a recoiling spring 25 which in turn bears with its other end in this instance against a cover 31 of the housing. The spring 25 acts upon the plate 116 to urge the plate in down direction and causes a closing of the upper sets of contacts by meanas of contact carrier 105 while causing the lower set of contacts to be opened via carrier and breaker element 10a whenever the one magnet (1, 2) of the electromagnetic actuation arrangement is not energized. In other words, the lower part of the illustrated structure is the same as circuit breaker A. However, upon energization of the single magnetic system the entire contact arrangement is pushed in up direction against the force of the spring 25. 
     Sleeve extension 6a pushes against sleeve extension 6b&#39;, for operating the upper circuit breakers. Thus, these two circuit breakers operate strictly in a reversing mode, one opens while the other one closes. The extensions 6a and 5b&#39; thus function not only for separating seperating the movable contact carriers sufficiently far from U-member 11, so that only one at a at a time can make contact, they also link directly the actuation of the two breakers. 
     The invention is not limited to the embodiments described above, but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.