US3602674A

US3602674A - Circuit breaker with locking and releasing train including adjustable rotatably mounted plate bars

Info

Publication number: US3602674A
Application number: US804157A
Authority: US
Inventors: Wolfgang Walter Koennecke; Gerhard Schleifenbaum
Original assignee: Hundt and Weber GmbH
Current assignee: Hundt and Weber GmbH
Priority date: 1968-03-08
Filing date: 1969-03-04
Publication date: 1971-08-31
Anticipated expiration: 1988-08-31
Also published as: FR2003478A1; GB1260713A; DE1638043A1

Abstract

This invention relates to a circuit breaker and, more particularly, to a circuit breaker with a locking and releasing train containing a series of levers so organized that the operation of the circuit breaker can be accurately controlled at the final lever in the series, which final lever is remote from the circuit breaking function.

Description

United States Patent [72'] inventors Wolfgang Walter Koennecke Bad Hamburg von der Hohe;

Gerhard Schleifenbaum, Huttental- Weidenau, both of, Germany [21] Appl. No. 804,157

(22] Filed Mar. 4, 1969 [45] Patented Aug. 31, 1971 [73] Assignee Hundt & Weber G.m.b.1-1.

Huttental-Geisweid, Germany [32] Priority Mar. 8, 1968 [33] Germany [54] CIRCUIT BREAKER WITH LOCKING AND RELEASING TRAIN INCLUDING ADJUSTABLE ROTATABLY MOUNTED PLATE BARS 12 Claims, 5 Drawing Figs.

[52] US. Cl 200/153 H, 335/35, 335/173, 337/57, 337/71 [51] Int. Cl IIOI-h 3/46,

{50] Field ofSearch ZOO/153.7,

[56] References Cited UNITED STATES PATENTS 2,981,811 4/1961 Steven et a1. 337/71 X 3,118,991 1/1964 Scott,Jr. 337/7 3,162,739 1'2/1964 Klein et a1. 337/57 X 3,185,792 5/1965 Buys et al. 335/23 X 3,182,157 5/1965 Brumfield ZOO/153.7 UX 3,263,051 7/1966 Gauthier et al.. ZOO/153.7 UX 3,309,635 3/1967 Walker 335/35 3,353,128 11/1967 Gauthier 335/35 Primary Examiner- Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Atmrney Norman S. Blodgett ABSTRACT: This invention relates to a circuit breaker and, more particularly, to a circuit breaker with a locking and releasing train containing a series of levers so organized that the operation of the circuit breaker can be accurately controlled at the final lever in the series, which final lever is remote from the circuit breaking function.

PATENTED M1831 i971 3502 674 J sum 1 or 2 INVENTORS WOLFGANG KOENNECKE GERHARD SCHLEIFENBAUM MMJW OR EY PATENTEUAUG31 I97! 3.602674

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2 or 2 INVENTORS WOLFGANG KOENNECKE GERHARD SCHLEIFENBAUM CIRCUIT BREAKER WITH LOCKING AND RELEASING TRAIN INCLUDING ADJUSTABLE ROTATABLY MOUNTED PLATE BARS This invention relates to a circuit breaker and, more particularly, to an electrical switch having an overload release operated by a bimetallic element and a solenoid.

BACKGROUND OF THE INVENTION It is common practice to use rockers for circuit breakers which extend over the effective range of the contacts assigned to the three phases and have adjustable action areas for one bimetal strip assigned to one phase and have also one magnet rotor. It is also known to design the rocker in two parts in such a way that one part can be adjusted relative to the other. By this method it is possible to adjust the desired response sensitivity of the bimetal strip. In practice, it was found that these adjusting devices are difficult to operate and are also difficult to adjust; it is especially difficult after the switch has been mounted. One of the disadvantages of such a two-part design of rocker is that the upper part (on which the bimetallic strips normally act) is difiicult to release. It has a larger moment of inertia relative to the hinge axis of the rocker than the lower part of the rocker, so that, particularly when the switch is vertically mounted, vibrational forces act on the rocker and tend to operate the rocker, so that it may cut off the electrical circuit that it is supposed to guard. In circuit breakers in which the rocker and the switch lock are mounted independently in the housing, especially large undesired deviations are observed with the switch-off values during mounting and by adjustments during operation. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.

It is therefore, an outstanding object of the invention to provide a circuit breaker which eliminates deviations in the switch-off valves.

Another object of this invention is the provision of a circuit breaker of simple design and of reduced fabrication costs.

A further object of the present invention is the provision of a circuit breaker which, even when mounted, can have the valve of its switch-off current readily changed.

It is another object of the instant invention to provide a circuit breaker in which the presence of disturbances, such as temperature variations and vibrations, do not influence its operation.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

SUMMARY OF THE INVENTION In general, this invention has to do with a circuit breaker with a switch lock consisting of plate bars and equipped with an arresting lever which is able to hold the switch lock in working position. For arresting purposes, the free end of the arresting lever is supported by a rocker which is swingable and has opposed adjustable parts. It is swingable for unlocking the switch lock from its base position magnetically through bimetallic strips. These kinds of circuit breakers are used for switching (controlling) and guarding of electrical equipment and power network parts. These switches do not only permit a manual and/or especially remote controlled power-driven onor-off switching of electric circuits, but they also permit automatic switch-off in case of unpermissible high current occurrences. Where the permissible upper current limits are exceeded, the switch-off will be made by the relatively slowly reacting bimetallic strips acting as overcurrent switch. In the case of short circuiting, a magnetic fast switch-off is executed. Additionally, there is supplied an inductive acting immediate switch-off.

The bimetallic strips, as well as the rotors of the magnetic fast switch-off, act on a rocker which is able to support an ar- BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawings, in which:

FIG. 1 shows a view of a circuit breaker cut off in front of plate bars of the switch lock and at its lower area showing the plate bar broken away for a better view,

FIG. 2 is an enlarged view of the intermediate lever having a U-shaped slot,

FIG. 3 shows an enlarged view of the rocker with the adjusting lever and the slot, and with the lever surrounding cover broken up,

FIG. 4 shows a section along line AA of FIG. 3, and

FIG. 5 shows a view of a modified form of the rocker with adjusting media supported within the cover of the housing.

DESCRIPTION OF THE PREFERRED EMBODIMENT The objects of this invention are achieved in such a way that the arrester lever is kept in position by short-acting components of a two-arm intermediate lever, where its extended arm supports itself with the free end on a support area of the rocker. In this case, the intermediate lever and the rocker are supported within the plate bars of the lock switch. The common housing between the plate bars of the switch lock does not only make adjusting exceptionally easy, but also the time constant of the critical and complicated engagement is reduced by the introduction of the intermediate lever. Especially, the reaction of the strong forces from the switch lock may not influence the critical adjustment as may not the thermal expansion influence certain displacements.

It was found important to extend the plate bars of the switch lock on one side to levers which shall support the intermediate lever and also the rocker. Another advantage is to design and arrange the two parts of the rocker in such a way that they have the same moments of inertia in regard to the swing axis of the rocker.

During the design of the intermediate lever, it was found to be of value to keep the supporting area of the arresting lever practically the same distance from the axis of the arresting lever as the axis is from the intermediate lever. It is also favorable to design the arresting lever with a projection at one side, which shall engage into a slot of the intermediate lever. This lever is open to one side; this is the side opposed to the turn axis of the intermediate lever, and the other extended side of the long slot guides the intermediate lever with its projection into operating position.

It is of advantage to design the carrying side of the slot, in its engaging area, slightly sloped, so that the slope may favor the release of the arresting lever. Outside the support area, the slope is purposely designed with constant slope or not constant (steeper) slope.

It was proven useful during design of the rocker to support a bearing plate with the plate bars swingable and keep it in tension by a spring where the bearing plate has a support plate close to the axis for the free end of the intermediate lever and is connected with the first, and the lower part of the rocker, and has support areas for the rotors of the release magnets,

etc. This first part is connected with the second part of the parts in tension act in this case as support forces. It was recognized to be of advantage to design the elements connecting the parts of the rocker with each other in such a way that they permit an axial displacement of the parts and, at the same time,

the support is displaced. On the other hand, the extended lever can be designed as a swing lever activating the displacement by swinging.- The support can be designed as a cam associated with the swing lever. It is also favorable to use as support the end of an adjusting screw to create a common adjustability to the three phases which, for example, may serve for compensation of fabrication deviations.

In case the displacement of the parts of the rocker is achieved by opposed shifting, then it is practical to surround the adjust media of the shifting part by a surrounding fork. The adjust media may be an adjust disc which is equipped with a pin placed out of center and engaging the fork. It was recognized to be of advantage to mount the adjust disc into the cover of the housing and surround the disc with a scale, and a mark on the adjust disc permits the reading of the corresponding adjustment. Also, by making the adjustment with a swing lever, it is possible to make adjustments after mounting. This is done in such a way that the swing lever is made of such a length that it extends, in its center position, up to the underneath of a slot of the cover of the housing. This slot is for practical reasons equipped with a transparent, removable cover and also is equipped with a scale permitting the reading of the corresponding position of the swing lever. It was also found to be of practical value to equip one part of the rocker with pivots which then are positioned within the castings of the other part and kept in tension by springs.

FIG. 1 shows the housing 1 and the spark chambers 2 in section; the contacts 3 and 4 and also the axis 5 of the switch lock 6 which operates the movable contact 4 can be seen. The switch lock 6 is operated by operating lever 7 which acts on a crank lever mechanism 8. The switch lock is kept in switch-on position with arresting lever 9 which is allowed to swing by means of the plate bars 10. The arresting lever 9 does engage with its side mounted pivot 11 into the slot 12 of an intermediate lever 13 which is arranged on shaft.l4 and where the shaft is also mounted swingably between the extending arms 15 of the plate bars. The free arm 16 of the intermediate lever is already in tension in the shown position of the capacity switch on support 17 of rocker 18 which is swingably connected by the shaft 19 stretching into the bearing plates 20 with the arms 15 of the plate bar. The rocker is shown in FIGS. 3 and 4 in section with the cover and broken up parts. The bearing plate 20 is connected with a lower part 21 made from pressed materials to which is attached swingably an upper part 22. Within the bearing plate 20 connected with lower part 21 is arranged a bolt 23 which serves as swing axis for the swing lever 24. A bushing tightened by the bolt 23and a friction ring positioned under the bushing and surrounding the support area of the swing lever secure the adjusted position of the swing lever. The swing lever 24 is equipped on its free end with a head 25 having a marking. This marking is of slot shape and permits, in addition to the defined reading of the position of the swing lever, adjusting of the swing lever with a screwdriver. The shaft of the swing lever supports the upper part 22 of rocker 18 with its wedge-shaped support strip 26, so that, by operating the swing lever, the lever supports itself over other areas with different support heights of the support strip and, therefore, is achieved an inclination of the upper part 22 against lower part 21. A true support is secured by a spring 29 under tension. The swing connection between the upper part 22 and the lower part 21 is formed mechanically simple and secure and the rocker may be taken apart easily, if required. The lower part 21 is equipped with bolts 27 which rest in castings 28 open to one side and belonging to the upper part 22. The springs 29, arranged on the free ends of bolts 27, bring lower and upper part together, in tension in such a way that the bolts are pressed into the castings and a momentum is applied to the upper part in direction of the swing lever and secures the mentioned sure'support of the wedge-shaped support strip 26.

- that around the axis 19 of rocker 18 approximately the same moments of inertia are applied. This arrangement is different from the conventional design by which the upper part 22 is made considerably heavier than the lower part and only sometimes a partial weight compensation is provided additionally. 1n the example shown, the lower part even is supplied with a somewhat larger moment of inertia than the upper part. By

this method, it is assured that, when vibration is present during mounting and operation, the rocker is kept in locked position, in comparison to the known designs where there is the tendency to slope the release device, and where the electric circuit may be broken by the vibration. The upper part 22 of rocker 18 is kept relatively small and has tongue-shaped extensions 30, which are equipped with adjusting screws 31 on their free ends. The shaft ends of the adjusting screws serve as stops for the bimetal strips; for example, bimetal strips 39 according to FIG. 1, and permit the individual adjustment of the release current of the phases. The desired value of the release current for the phases may be adjusted together by operating the swing lever 24 by which all of the upper part is sloped. Another support surface 32 is arranged for activating further elements connected with the housing, so that a manual activation may be executed with an operating button or lever extending through the cover. The lower part 21 contains three operating levers 33 which are actuated in the case of short-circuiting by rotors of magnets 40 activating the magnetic quick release, and by swinging of the rocker, pull forward the support 17 underneath the free arm 16 of intermediate lever 13. The lower part 21 is equipped, furthermore, with a release piece 34 having a sloped operating surface which, for exam ple, may be operated by a release mechanism present on the housing and a release lever 35 having a corresponding sloped counterface.

Within the cover 36 is arranged a slot 37 which is commonly closed off by cover plate 38. This cover plate may be opened without taking off the cover for the housing, so that the head 25 of swing lever 24 may be reached and adjusted. By a transparent cover plate, it is possible to read the corresponding adjustment of the release current on a scale 41 which makes it also easy to adjust the swing lever 24 in case a change of the release current is desired.

In FIG. 5 is shown a special simple design of a rocker offering further adjust possibilities for releaseof the switch lock. The lower part of rocker 42 is equipped with astationary lever 43. On the free end of the lever is mounted an adjustment screw 44 which supports itself on a wedge-shaped support strip 45 of upper part of the rocker. The bearing pin, connect ing the upper and lower part together in a slope, and also the pin surrounding eyes are shaped in such a way that they permit an axial displacement of the upper part against the lower part.

The distance of displacement is, for practical reasons, adjusted to the length of the support strip 45. By displacement of the upper part against the lower part, the supporting area of supporting strip 45 changes the corresponding support height because of its wedge-shaped design. For displacement and, consequently, for the change of the slope between the upper and lower part of the rocker, the upper part is equipped with a fork 46 which surrounds a pin 48 placed out of center within the adjusting disc 47. The adjusting disc 47 is kept turnable within the cover 49 (here shown broken up) of housing. The disc contains a slot 50 which permits the adjustment, for example, with a coin. The slot continues one-sided up to the periphery of the adjusting disc and is reformed towards the mark 51 and colored to permit the reading of the relative position of the adjusting disc 47 on hand of a surrounding scale 52 of cover 49. By this arrangement, it is possible to designate the scale division of scale 52 with the release currents. The construction of the switch lock according to this invention secures, in addition to a high release sensitivity, also close fabrication tolerances. The individual bimetal strips are adjustable with the corresponding adjusting screws. The adjustment to the present scale 52 is made on this design by operating and lockingof the adjusting screw 44, so that it is possible at any time during operation to read the adjusted release current with the mark 51 on scale 52, or it is possible without any special prework to adjust clearly with the adjusting disc a desired release current.

The recommended design of the capacity switch, according to this invention, contains a number of exceptional advantages. The force necessary for adjusting the rocker is reduced considerably because the arresting lever 9 is not supported directly over intermediate lever 13. This intermediate lever does not only relieve the support area from strong initial tension, but also the bearings of the rocker. Through the design of the intermediate lever with supportingslot 12 it is achieved that the arresting lever 9 in it s switch-on position creates none, or only a very small torsion momentum. The momentum necessary to hold the rocker or for support of the free arm 16 of intermediate lever 13 could be made by a spring in tension (not shown in this drawing). After release, the intermediate lever will be dipped, so that from then on a continuous growing momentum is transferred to the side of the slot which leads to a fast shifting ,of the lever, so that by the use of the intermediate lever alone the sensitivity is increased. Furthermore, an improvement of the behavior during release can be made by making the carrying sides of the slot 12 outside the support area 53 steeper or constant or not constant; that is, increasingly steeper, so that also by this shape of the slot side, a fast reaction is secured. in the shown example, support area 53 follows according to the angle a and by further extension not constant increasing, the support side 55 by the angle [3. A constant increase of the slope is shown in an alternate side 54. The increased sensitivity by the use of the added intermediate lever may be used in the sense of restricting tolerances. By supporting of the rocker on the switch lock, in its plate bars, the displacement, as common in the conventional design, is completely eliminated. These displacements on known capacity switches were created because the rocker is kept in a special support which is connected with thehousing bottom. By such a separate kept support, mechanical expansion or elastic stressescould bring about displacements of the axis of the parts which work together which, in turn, can react to the magnitude of the release currents. Furthermore, it was proven that by the support of the rocker on the switch lock or its plate bars, the optimum position of the individual parts to each other is secured from the point of fabrication, so that special adjust work during mounting is not necessary. However, the rocker design constructed in accordance with this invention secures an adjustability of the corresponding release current, and the extended designs permit the accurate relief of the release current or the influence of the current arbitrarily without opening of the switch. The advantageous design of the adjust mechanism is additionally very simple and inexpensive, and the shape of the rocker secures furthermore against vibration or shocks which may, as on common capacity switches, influence the switch operation.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

l. A circuit b eaker having a locking and releasing train consisting of n a. a circuit breaker housing,

b. plate bars rotatably mounted in the housing and having a first position in which the circuit breaker circuit is closed and asecond position in which the circuit breaker circuit is open,

. an arresting lever rotatably mounted in the housing, having a first and a second position which bring about corresponding positions in the contacting means and having a pin extending from it parallel to its axis of rotation,

d. a rocker rotatably mounted in the housing and residing generally in a first position but movable to a second position when acted upon by the circuit breaking sensors of the circuit breaker, and i e. an intermediate lever rotatably mounted in the housing, biased in a second position which allows the arresting lever to move to its second position, but capable of entering a first position in which it is held by the rocker when said rocker is in its first position but not held when said rocker is in its second position and, when said intermediate lever is in said first position, it forces said arresting lever to enter its said first position by engaging the pin of the arresting lever with an open-ended slot in said intermediate lever, the arresting lever having a pin engageable in a one-sided open slot on the intermediate lever, the extended side of the slot bringing the intermediate lever into operative position by engagement with the pin, the carrying side of the slot in its support area being slightly sloped in a manner which is favorable to the release of the arresting lever.

2. A circuit breaker as recited in claim 1, wherein the slope of the carrying side of slot increases constantly in slope in an area outside of the pin support area in the intermediate lever.

3. A circuit breaker having a locking and releasing train consisting of a. a circuit breaker housing,

b. plate bars rotatably mounted in the housing and having a first position in which the circuit breaker circuit is closed and a second position in which the circuit breaker circuit is open, I

c. an arresting lever rotatably mounted in the housing, having a first and a second position which bring about corresponding positions in the contacting means and having a pin extending from it parallel to its axis of rotation,

d. a rocker rotatably mounted in the housing and residing generally in a first position but movable to a second position when acted upon by the circuit breaking sensors of the circuit breaker,

e. an intermediate lever rotatably mounted in the housing, biased in a second position which allows the arresting lever to move to its second position, but capable of entering a first position in which it is held by the rocker when said rocker is in its first position but not held when said rocker is in its second position and, when said intermediate lever is in said first position, it forces said arresting lever to enter its said first position by engaging the pin of the arresting lever with an open-ended slot in said intermediate lever, and

f. a support member for engagement by the free end of the intermediate lever, a bearing plate connecting the plate bars swingably to the lower part of the rocker, which part has an operating lever for a release magnet.

4. A circuit breaker as recited in claim 3, wherein the parts of the rocker are swingably connected with each other and one upper part has support strips which have the shape of a wedge on which thelower part is supported by means of an extended lever.

5. A circuit breaker as recited in claim 4, wherein the extended lever is designed as a swing lever.

6. A circuitbreaker as recited in claim 4, wherein the end of the extended lever is providedwith an adjusting screw which engages a wedge.

7. A circuit breaker as recited in claim 3, wherein the part of the rocker to be displaced is equipped with a fork surrounding an adjusting pin.

8. A circuit breaker as recited in claim 7, wherein the adjusting pin is located in an adjusting disc having the adjusting pin located out of center and engageable with the fork.

9. A circuit breaker as recited in claim 8, wherein the adjusting disc is mounted within the cover of the housing and the disc is equipped with a mark which permits reading of a scale surrounding the disc.

. .3. a with a scale.

12. A circuit breaker as recited in claim 4, wherein bolts of the lower part of the rocker are kept under tension by springs within the castings of the upper part.

Claims

1. A circuit breaker having a locking and releasing train consisting of a. a circuit breaker housing, b. plate bars rotatably mounted in the housing and having a first position in which the circuit breaker circuit is closed and a second position in which the circuit breaker circuit is open, c. an arresting lever rotatably mounted in the housing, having a first and a second position which bring about corresponding positions in the contacting means and having a pin extending from it parallel to its axis of rotation, d. a rocker rotatably mounted in the housing and residing generally in a first position but movable to a second position when acted upon by the circuit breaking sensors of the circuit breaker, and e. an intermediate lever rotatably mounted in the housing, biased in a second position which allows the arresting lever to move to its second position, but capable of entering a first position in which it is held by the rocker when said rocker is in its first position but not held when said rocker is in its second position and, when said intermediate lever is in said first position, it forces said arresting lever to enter its said first position by engaging the pin of the arresting lever with an open-ended slot in said intermediate lever, the arresting lever having a pin engageable in a one-sided open slot on the intermediate lever, the extended side of the slot bringing the intermediate lever into operative position by engagement with the pin, the carrying side of the slot in its support area being slightly sloped in a manner which is favorable to the release of the arresting lever.

3. A circuit breaker having a locking and releasing train consisting of a. a circuit breaker housing, b. plate bars rotatably mounted in the housing and having a first position in which the circuit breaker circuit is closed and a second position in which the circuit breaker circuit is open, c. an arresting lever rotatably mounted in the housing, having a first and a second position which bring about corresponding positions in the contacting means and having a pin extending from it parallel to its axis of rotation, d. a rocker rotatably mounted in the housing and residing generally in a first position but movable to a second position when acted upon by the circuit breaking sensors of the circuit breaker, e. an intermediate lever rotatably mounted in the housing, biased in a second position which allows the arresting lever to move to its second position, but capable of entering a first position in which it is held by the rocker when said rocker is in its first position but not held when said rocker is in its second position and, when said intermediate lever is in said first position, it forces said arresting lever to enter its said first position by engaging the pin of the arresting lever with an open-ended slot in said intermediate lever, and f. a support member for engagement by the free end of the intermediate lever, a bearing plate connecting the plate bars swingably to the lower part of the rocker, which part has an operating lever for a release magnet.

4. A circuit breaker as recited in claim 3, wherein the parts of the rocker are swingably connected with each other and one upper part has support strips which have the shape of a wedge on which the lower part is supported by means of an extended lever.

6. A circuit breaker as recited in claim 4, wherein the end of the extended lever is provided with an adjusting screw which engages a wedge.

10. A circuit breaker as recited in claim 5, wherein the swing lever in its center position extends up into the lower portion of a slot in the cover of the housing.

11. A circuit breaker as recited in claim 10, wherein the slot is equipped with a transparent, removable cover plate and also with a scale.