US1961573A - Circuit breaker - Google Patents

Description

J. R. SANBORN CIRCUIT BREAKER June 5, 1934.

Filed Nov. 4, 1930 4 Sheets-Sheet l (D Smmwcoz June 5, 1934. J, R, SANBORN 1,961,573

C RCUIT BREAKER Filed Nov. 4, 1,930 4 sheets-sheet 2 June 5, 1934. J. R. sANBoRN 1,961,573

CIRCUIT BREAKER Filed Nov. 4, 1930 4 Sheets-Sheet 3 June 5, 1934. J. R. SANBORN CIRCUIT BREAKER 4 Sheets-Sheet 4 Filed Nov. 4. 1930 Patented. June 5, 1934 UNITED STATES CIRCUIT BREAKER John R. Sanborn, Bethlehem, Pa., assignor to Roller-Smith Company, a corporation of New York Application November 4, 1930, Serial No. 493,297

14 Claims.

This invention relates particularly to the release from the handle type of circuit breaker, or so-called nonclosable under an abnormal circuit condition, such as overload, under-voltage, or any other desired controlling factor or factors. The breaker is also adapted, in some of its improved features, to be used with breakers of other than the release from the handle type.

The main object of the invention is to produce an improved circuit breaker which will be rugged in form of construction, dependable in operation and durable with long continued use; and to accomplish this by an improved form of construction of a simple character in the form and relationship of its parts and which permits economical manufacture and simplicity in assembling. Another object is the provision of a form of construction wherein the operating handle may be located close to the base, thereby avoiding any undue projection thereof or its being subject to accidental interference, and likewise permitting enclosure by a shallow casing, where enclosure of the parts is desired. Another object, where the handle is outside the casing, is to provide for the location of the operating handle at the side of the breaker close to the base where it is in a protected position. lt likwise permits convenient enclosure of the breaker by permitting the removal of the outer casing without disturbing the operating handle. Another object is to provide an improved form of mechanism wherein the controlling force for causing the opening of the breaker may be made quite small. Another object is to provide a simple-form of construction of breaker wherein any desired number of switch elements may be used and all controlled by one closing mechanism, and all released by the effect of any one of a number of different controlling coils. Other 0bjects and advantages of this invention will be understood from the following description and accompanying drawings which illustrate a preferred embodiment thereof.

Fig. l is a front elevation of a three pole circuit breaker embodying my invention provided (Cl. D-89) leased for permitting the opening of the breaker; Fig. 7 is a side view of the main hook element; and Fig. 8 is a side view of the latch holding element.

Referring to Figs. 1 and 2, thc breaker is shown mounted on an insulating base plate 1 which is shown secured to the back of the inner portion 2 of an enclosing casing. The breaker illustrated is of the three pole type, one set of terminals 3 being mounted upon the lower portion of the base plate and the other set of terminals 3a being mounted upon the upper portion of the base plate. The inner portion of the enclosing casing is comparatively shallow, and the outer portion 2a of the casing is likewise comparatively shallow and is shown as telescoping over a portion of the inner casing and secured in place by wing nuts 2b which engage studs extending outwardly from the base plate.

The yieldable fixed contacts 4 of the breaker are suitably mounted upon the base plate and provided with the usual auxiliary carbon contacts 4a. The contact arms 5 engage the yieldable contacts and have auxiliary carbon contacts 5a at their upper ends. The contact arms are fixed to, but insulated from, a shaft 6 which is rotatably supported in two bearing brackets 7, one at each side of the breaker. These brackets are xed to the base plate and have outwardly extending portlons 'la for supporting the contact arm shaft 6. The right hand bearing bracket has an extension 7b to which one end of the operating spring 7c is secured, the other end of the spring being secured to an arm 7d secured to the contact arrn shaft. This spring serves to quickly throw the breaker to open position when released. Fixed to the contact arm shaft is an outwardly extending arm 8 carrying a curved plate 8a marked On and "Off on its face. Evidently, the position of the curved plate 8a Will show whether the breaker is open or closed, a small opening in the front portion 2a of the casing permitting the Word On or Off to be exposed, according to the condition of the breaker.

A The operating handle 9 for closing the breaker, is external to the casing and located at the right hand side thereof and is connected to a shaft 9a, which is pivotally supported by two out'- wardly extending bearing supports 9b and 9c secured to the base plate within the casing. Fixed to the handle shaft is a crank element 9d which extends downwardly from the handle shaft and when in closing position strikes against a stop 9e on'the base plate, formed by an extension from the support for the handle bearing brackets, or may be an independently mounted plate or nut to serve as a stop for the crank element. 'Ihis stop prevents the breaker from being unduly strained by the operator when closing the breaker, and also serves to limit the over-center position of the crank element 9d, as hereinafter explained.

The breaker is closed by means of a hook, the operation of which is controlled by the handle through the crank element 9d. The closing hook is made up of two side plates 10a and 10b clamped together at their lower ends and also pivotally connected to the crank pin 9! in the outer end of the crank element, as shown in Pigs. 1 and 5. 'I'he side plates of the closing hook are spaced apart from each other, in their upper portions, their upper ends forming a pair of hooks 10c and 10d. Fixed to the contact arm shaft 6 is an inwardly extending crank arm 11 which carries a pin 11a at its inner end and extending sidewise therefrom to the right of the arm ll. The hooks 10c and 10d are adapted to engage the pin 11a for the purpose of closing the breaker. That is, when the operating handle 9 is turned upwardly to the dotted position indicated in Fig. 3, it swings the crank 9d to the dotted position shown in Fig. 3 and correspondingly raises the side plates 10a and 10b. so that the hooks 10c and 10d pass over the top of the pin lla of the arm l1 in their upper position corresponding to the open position of the contact arms 5, as indicated in dotted lines in Pig. 3. Downward movement of the closing handle will then cause the contact arms to be moved to their closed position, indicated in full lines in Fig. 3.

As it is desired to permit the opening of the breaker when attempted to be closed, in case of the occurrence of an abnormal circuit condition, and also during running conditions, without disturbing the closing handle from its closing position, the hooks 10c and 10d are shaped, where they engage the pin 11a, so as to readily pass of! the pin and release the contact arm shaft, so vthat the breaker may move to open position. Thus. the shape of the engaging faces or edges of these hooks with the pin 11a form substantially plane surfaces; and were it not for auxiliary retaining means, the hooks would run off the pin or roller 11a. Under such conditions, the breaker could not be closed, or held closed, by the hooks 10c and 10d Therefore, there is provided an auxiliary hook holding element 12. well shown in Figs. 3, 4 and 6 and separately shown in Fig. 8. 'I'his holding latch or hook is pivotally mounted between the upper portions of the hook plates 10a and 10b on a pin 12a. which pin is mounted upon and extends between the side hook plates. The holding hook has secured to it, at its upper end, a downwardly extending leaf spring 12b, for the purpose of normally forcing the upper portion of the holding hook inwardly, so as to normally engage the pin 11a and thereby prevent the hooks 10c and 10d from sliding off the pin.

The spring 12b also serves another function of engaging another latching element 13 to hold it in normal position. The latch 13 is pivotally mounted at its inner end upon a pin 13a, extending between the side plates 10a and 10b. The outwardly extending portion of the latch 13 is adapted to be engaged by a tripping element upon the occurrence of an abnormal circuit condition and is raised to release the breaker, The

inner end of the latch 13 beyond the pivot 13a forms the hook for engaging and normally restraining the lower end of the latch holding element 12. These parts are shown in their normal closed position'in Figs. 3 and 4, where it is seen that the lower end of the holding latch 12 is restrained by the inner end of the latch 13, so as to be locked to the pin 11a, while the leaf spring 12b engages a notch in the upper edge of the latch 13 in front of the pivot 13a, so as to tend to hold the outer end of the latch 13 down. When the holding latch is released, the spring tends to force the upper portion thereof over the pin 11a to such a position that the lower end of latch l2 is engaged by and retained by the inner end of the hook 13. Fig. 6 shows the relation of the latching elements to each other at a time when the outer end of the latch 13 has been raised by the tripping element, permitting the lower end of the latch 12 to be released and unhooked from the pin 11a. This obviously permits the hooks 10c and 10d to pass oi! the pin 11a and thus permit the opening of the breaker. In this releasing action, although the spring 12b tends to hold the latch 12 in position on the pin 11s, the force tending to open the breaker tends to move the pin 11a. upwardly, so that, when the holding latch 12 is released, the pin 11a swings the latch 12 counter-clockwiseon the pivot 12a against the action of the spring 12b. Thus the lower end of the latch 12 is thrown inwardly by the action of the pin 11a, until this pin has passed from under the holding elements, after which, the spring 12b tends to turn the latch 12 in a position to again engage the pin lla during the closing operation of the breaker. It should also be noted that when the breaker is closed the center line of the pin 9! is passed beyond the dead center line extending between the axis of the handle shaft 9a and the axis of the pin 11d. T hus in the closed position of the operating handle of the breaker, the breaker is held closed by reason of the over-center position of the pin 9]. Obviously, when the pin 11a is re- 120 leased, the breaker handle and parts controlled thereby, remain in position corresponding to the closed position of the breaker, until raised by the operator for the purpose of closing the breaker in the manner already explained.

In the breaker shown in the drawings, there are provided means for automatically tripping the breaker upon the occurrence of over-load and also upon the occurrence of under-voltage, two over-load controlling coils and two undervoltage controlling coils being shown and being adapted for connection in a three phase circuit. Each of these controlling elements serves to raise the front end of the single tripping latch 13. Thus any one of the controlling elements may automatically cause the opening of the breaker through its effect upon this single releasing element. For securing this result, there is provided a single tripping element 14 in the form of a pin which extends across the front of the breaker and is located immediately under the front end of the tripping latch 13. The controlling elements are related to this tripping pin so that upon the occurrence of any one or more abnormal conditions, this pin would be raised to actuate the releasing latch. The tripping pin is mounted as shown in Figs. l, 4 and 5.

It is carried by a tripping bracket 14a in the form of a metal plate having upwardly turned side portions through which the pin passes and by 'the rear leg of the magnet.

which the pin is carried. These side portions of the bracket extend rearwardly to form ears 14h which are in turn pivotally mounted upon a hinge pin 14o. 'I'his hinge pin is in turn supported by studs 14d which are xed to the base plate. A spring 14e encircles the hinge pin` and has one end secured thereto while the other end is brought forward and engages the upper surface of the tripping bracket which assists gravity in tending to hold it and the tripping pin in their lowest position.

The controlling magnets are all supported upon a common horizontal plate 15 which in turn is supported by a pair of forwardly extending jaws l5a suitably xed to the base plate. Each of the magnets has a U-shaped iron core with upwardly extending legs upon which the coils are mounted. The cores are xed to and supported upon the plate 15 and the legs of each core lie in a vertical plane perpendicular to the base plate.

The cores 16 of the two over-load coils are particularly shown in Figs. 4 and 5 with the over-load coils 16a diagrammatically indicated thereon. In Fig. 4 the over-load coil is omitted upon the rear leg of the core for simplicity and it is immaterial, as far as the present invention is concerned, whether both legs of the core are provided with coils, or only one leg is so provided. The particular form of magnet will be made as desired to suit the particular conditions. On the upper end of each front leg of the cores 16, is pivotally mounted an armature 17. Its shape is indicated in Figs. 4 and 5 and is in the form of a plate extending over the front leg of the core and having downwardly extending side portions over the front leg of the core, to which it is connected by a pin 17a which passes through the side portions of the armature and through the front leg of the core. Each of these armatures has a rearwardly extending portion 171) which extends over the rear,leg of the over-load magnet. When the overload current attains a predetermined limit, in either of the over-load magnets, its respective armature will be attracted and cause the rear portion thereof to move downwardly towards The front end of each over-load armature is perforated to receive a horizontally extending pin 17o, one end of which pin is in hook formto receive one end of a spring 17d, as shown in Fig. l. This spring extends downwardly and is suitably secured to the plate 15. This spring tends to hold the front end of its over-load armature down and thus cause the rear end of the armature to be raised above the rear pole of the magnet, as shown in Fig. 4, under normal conditions. Any suitable stop or adjustable means is provided to limit the unattracted position of the armature, in any o1 the well-known ways. A graduated scale may be placed adjacent to the armature, said scale to indicate the current for which the armature is set to trip. The tripping bracket 14a which is located above the over-load magnets, is provided with a pair of downwardly extending portions 14j, which respectively rest upon the front ends of the overload armatures. determined over-load, the armature of the respective magnet carrying the over-load will be attracted and the front end thereof raised. This in turn causes the raising of the front end of the tripping bracket around the hinge pin 14e and thereby raises the tripping pin 14 to It is evident that upon a pre-v trip the releasing latch 13, to cause the opening of the breaker, as already described.

The low voltage, or under-voltage, controlling magnets 18 are shown located one at each side of the base plate. Each of these magnets is provided with a pair of plates 18a in i'rontA of the coil and suitably secured to the core of the magnet, see Figs. l and 2.. These plates each have an outward extension 18h at their upper ends and carry a pin extending between them on which is pivoted the armature 18o, the rear portion extending over the poles of the magnet. The front end of the armature has a spring 18d connected to it which extends downwardly and is fastened to a pin 18e extending between the lower ends of the plates 18a. The inner portion of the armature extends under the tripping pin 14, so that when it is released upon the occurrence of a predetermined under-voltage, it will be thrown upwardly by the action of the spring 18d. and so raise the tripping pin to cause the automatic opening of the breaker, in the manner already described. For the purpose of causing the under-voltage armature to be pushed toward the poles of its magnet when the breaker is closed and to so give the magnet an opportunity to retain the armature in place, under normal voltage conditions, the armature is provided with a projection 18j and an inclined downwardly extending surface at its rear end, as shown in Fig. 2. This inclined end of the armature is engaged by any suitable projection mounted upon the contact arm shaft 6, or controlled by the movement thereof. In Fig. 1, at the left, is shown a plate 19 mounted upon the contact arm shaft and having an extension 19a which is over the' armature of the left-hand voltage magnet. The right hand voltage magnet is controlled by a similar projection 19a which in this instance is an extension from the arm or plate 8 carrying the indicator. Referring to Fig. 2, it will be evident that when the breaker is open, the projections 19a will be nearer the base plate than when the breaker is closed, and that the inner ends of the voltage 120 armatures will be above the retained position shown in Fig. 2. Thus during the closing of the breaker, the projections 19a will move outwardly and engage the inner surfaces of the voltage armatures and force them in position 125 to be magnetically held if normal voltage exists, the projections 19a. in the meantime passing over and in front of the projections 18j of the armatures to the position shown in Fig. 2. If under-voltage exists in either circuit, the arma- 130 ture corresponding thereto will not be held by its magnet; and the spring 18d will cause it to be thrown to raise the tripping pin 14, the projection 19a. having passed away from the projection 18j of the armature.

It will be understood that the automatic tripping magnets may be variously arranged in relation to the breaker mechanism and may, of course, be made to respond to any abnormal condition desired and may be variously connccted to suit the particularrequirements. In the present case, as indicated in the drawings, the left hand under-voltage magnet 18 is connected between the left hand terminal 3 and the middle terminal of the three phase circuit; and the right hand voltage magnet is connected between the right hand terminal 3 and the middle terminal 3. The right hand over-load coil is connected between the right hand terminal 3 and the right hand contact arm 5; and the left 150 hand over-load coll is connected between the left hand terminal 3 and the l'eft hand contact arm 5, while the middle terminal 3 is connected directly to the middle contact arm.

Although the particular circuit breaker described is adapted for three phase alternating current, my invention is likewise adapted for the control of direct current and may be used in various types of circuit breakers. It is also evident that it is adapted for the control of a single pole breaker, as well as for breakers having any desired number of poles, or switch arms, all controlled by a single closing and releasing device and subject to automatic opening by any desired number of control magnets operating under any desired conditions. Where necessary, insulating barriers may be placed between the difi'erent contact arms and the contacts controlled therebyv for the purpose of preventing flashing over from one pole to the adjoining pole, but such barriers are omitted from the present drawings for the sake of simplicity and clearness.

Although' I have described a preferred embodiment of my invention, it will be understood that the same may be embodied in various forms of construction and relationship of the parts and various modifications made without departing from the scope thereof.

vI claim:

1. A circuit breaker comprising a base plate, a rotatable contact arm, a pivotal support for said contact arm mounted on said base plate, a rotatable operating shaft supported on said base plate below said support, an operating handle connected with said shaft and located at one side of the breaker, an arm fixed to said shaft below said contact arm, an arm connected with said contact arm and extending inwardly toward said base plate, and a releasable hook device connecting said inwardly extending arm and said arm fixed to said shaft for closing said contact arm.

2. A circuit breaker comprising a base plate, a rotatable contact arm, a pivotal support for said contact arm mounted on said base plate, a rotatable operating shaft supported on said base plate below said support, an operating handle connected with said shaft and located at one side of the breaker, an arm fixed to said shaft below said contact arm, an arm connected with said Contact arm and extending inwardly toward said base plate, and a releasable hook device connecting said inwardly extending arm and said arm fixed. to said shaft for closing said contact arm, said device comprising a main latch and a latch for holding the main latch.

3. A release from the handle circuit breaker comprising a base plate, a contact arm, a pivotal support on said base plate for said contact arm, a crank arm rigidly connected with said contact arm and extending inwardly toward said base plate, a hook element releasably connected with said crank arm, an operating shaft below said support, a crank arm on said operating shaft connected with said hook element, a holding latch for maintaining said hook element in operative engagement with said first-named crank arm, and a tripping device for releasing said holding latch.

4. A release from the handle circuit breaker comprising a shaft, a contact member fixed to said shaft, an arm connected with said shaft, a pin carried by said arm, a hook element engaging said pin, a holding latch pivotally supported on said hook element and engaging said pin for normally holding said hook element in engagement with said pin, an operating shaft having an arm connected with said hook element, and means for automatically tripping said holding latch.

5. A release from the handle circuit breaker comprising a shaft, a contact member fixed to said shaft, an arm connected withsaid shaft, a pin carried by said arm, a hook element engaging said pin, a holding latch pivotally supported on said hook element and engaging said pin for normally holding said hook element in engagementv with said pin, an operating shaft having an arm connected with said hook element, and means for automatically tripping said holding latch, said last-named arm passing beyond the center line of said pin and said operating shaft in the closed position of the breaker.

6. A circuit breaker comprising a base plate, a rotatable contact arm, an arm connected with said contact arm and extending inwardly toward said base plate, said arm having a pin on its inner end, a rotatable operating shaft supported on said base plate below said contact arm, and an upwardly extending hook moved upwardly and downwardly by rotation of said shaft, the upper end of said hook passing over said pin when in its upper position to engage the same and causing the contact arm to close by the downward movement of said hook.

7. A release from the handle circuit breaker comprising a rotatable Contact element, a rotatable operating element, and a latching mechanism operatively connecting said elements, said mechanism comprising a main latch for moving said contact element to closed position, a latch for holding said main latch in operative engagement for moving said contact element, and a tripping latch for normally restraining said holding latch.

8. A release from the handle circuit breaker comprising a rotatable contact element, a rotatable operating element, a latching mechanism operatively connecting said elements, said mechanism comprising a main latch for moving said contact element to closed position, a latch for holding said main latch in operative engagement for moving said contact element, a tripping latch for normally restraining said holding latch, and means for automatically moving the tripping latch.

9. A release from the handle circuit breaker comprising a rotatable shaft, a contact member mounted on said shaft, an operating shaft having a crank arm, and a releasable hook device connecting said crank arm and said first named shaft, said crank arm being carried over-center in the closed position of the breaker.

10. A release from the handle circuit breaker comprising a shaft, a contact member carried by said shaft, an arm connected with said shaft, a pin carried by said arm, a pair of hook plates engaging said pin, a holding latch for retaining said hook plates in engagement with said pin andi pivotally supported between said plates and also engaging said pin, an operating shaft having an arm connected with said hook plates, and means for automatically tripping said holding latch.

11. A release from the handle circuit breaker comprising a shaft, a contact member carried by said shaft, an arm connected with said shaft, a pin carried by said arm, a pair of hook plates engaging said pin, a holding latch for retaining said hook plates in engagement with said pin and pivotally supported between said plates and elso engaging said pin, an operating shaft having an arm connected with said hook plates, and means for automatically tripping said holding latch, said arm passing beyond the center line of said pin and said operating shaft in the closed position of the breaker.

12. A circuit breaker comprising a common rotatable shaft, a plurality of movable contact members carried thereby and fixed thereto, a rotatable operating shaft, a releasable latching device operatively connecting said operating shaft and said first named shaft for rotating said rst-named shaft and thereby moving said contact members to closed position, a tripping mechanism for releasing said latching device, a single movable element for controlling said tripping mechanism, and a plurality of magnets for individually controlling the movement of said single element.

13. A circuit breaker comprising a common rotatable shaft, a plurality of movable contact members carried thereby and fixed thereto, a rotatable operating shaft, a releasable latching Gti device operatively connecting said operating shaft and said first named shaft for rotating said first-named shaft and thereby moving said Contact members to closed position, a tripping mechanism for releasing said latching device, a single movable element for controlling said tripping mechanism, a plurality of magnets for in dividually controlling the movement of said single element, a main base plate for the breaker, and a common support for said magnets mounted on said main base.

14. A release from the handle circuit breaker comprising a rotatable shaft, a plurality of contact members carried by said shaft and fixed thereto, a rotatable operating shaft, a device connecting said shafts for closing the breaker by rotation of said first-named shaft, said device comprising a hook, a holding element for retaining said hook in position, a pivoted element for controlling the movement of said holding element, a plurality of tripping magnets, and a movable element actuated by each of said tripping magnets for aiecting said pivoted e1- ement to cause the release of said holding element.

JOHN R.. SANBORN.

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