US2988605A - Circuit breaker apparatus - Google Patents

Description

June 13, 1961 w. VAN GENT 2,988,605 CIRCUIT BREAKER APPARATUS Filed Aug. 12, 1959 2 Sheets-Sheet 1 June 13, 1961 w. VAN GENT CIRCUIT BREAKER APPARATUS 2 Sheets-Sheet 2 Filed Aug. 12, 1959 2,988,605 CIRCUIT BREAKER APPARATUS Willem van Gent, Slikkerveer, Gem. Ridderkerk, Netherlands, assignor to N.V. Electrotechnische Industrie voorheen Willem Smit & Co., Slikkerveer, Gemeente Ridderkerk, Netherlands, a Dutch limited company of the Netherlands Filed Aug. 12, 1959, Ser. No. 833,197 Claims priority, application Netherlands Aug. 18, 1958 Claims. (Cl. 200-2) This invention relates to circuit breakers in general and in particular to circuit breakers for large electric currents in which ends of two conductors are conductively connected by means of one or more rollers or roller contacts of conductive material in the closed position of the circuit. The rollers or roller contacts are pivoted on an offset shaft which is submitted to the pressure of a spring in a direction perpendicular to the direction of the shaft for producing the contact pressure between the rollers and the ends of the two conductors. The circuit breaker has a rotatable control shaft for controlling the movement of the rollers or roller contacts. The conductors which are arranged for connection by the roller or rollers may each be provided with a contact surface to facilitate conduction between the conductor and the roller or rollers.

Circuit breakers of the aforesaid kind will hereinafter be referred to as circuit breakers of the kind set forth. Prior art circuit breakers of the kind set forth are generally known and provided with only one set of roller contacts.

circuit breaker apparatus.

It is a further object of this invention to provide circuit breaker apparatus which is reliable, rugged, and simple in design and construction and thereby requiring little or no maintenance. If maintenance is required the apparatus is constructed so that maintenance may be easily afiected.

It is another object of this invention to provide a circuit breaker of the kind set forth which allows multiple, heavy duty switching to be performed in a restricted space.

According to one feature of the invention there are arranged in a circuit breaker of the kind set forth two contact surfaces in an advantageously substantially mutually perpendicular spatial relation adapted to be operatively electrically connected by a first roller or set of roller contacts. A second roller or set of roller contacts controlled by the same control shaft as the first roller is provided for electrically connecting two further contact surfaces also advantageously arranged in substantially mutually perpendicular spatial relation. One of the first mentioned contact surfaces and one of said further contact surfaces being provided on one and the same conductor. Said conductor is advantageously substantially strip shaped, its contact surfaces being positioned substantially on one of its large boundary surfaces. Preferably there is arranged in the proximity of each contact surface an insulating bearing stop or support member to engage the roller contact in the open position.

In a preferred embodiment of the invention four substantially strip shaped conductors each provided with a contact surface at each end for the roller contacts are arranged substantially according to the sides of a square. In another embodiment two substantially parallel conductors may be connected by a substantially strip shaped metallic connecting member, extending in a direction plane which is perpendicular to the axial direction of the control shaft, said connecting element being connected to a long, small boundary surface or edge of each of ted States Patent 0 F Patented June 13, 1961 'ice said conductors. The circuit breaker may have two connecting elements of this kind, in which case the control shaft may preferably be supported in an insulating Way in both strip shaped connecting members, or the connecting member may be journaled on said control shaft.

In another feature of an embodiment of this invention one of two adjacent strip shaped conductors, which cannot be connected by a roller contact directly, is provided with a fixed contact piece, whereas the other of said two adjacent conductors is provided with a movable contact piece arranged for cooperation with said fixed contact piece. The control shaft is provided with a cam adapted to control said movable contact piece. Preferably the movable contact piece is arranged on a tumbler which is provided with two cam rollers arranged for mechanical cooperation with the cam attached to the control shaft. Limiting members may be provided to determine the extreme positions of the control shaft.

Other objects and features of this invention will become apparent when the following description is taken in conjunction with the accompanying drawings in which:

FIGURES 1 and 2 show schematically two different positions of a circuit breaker in a direct current system, said circuit breaker being arranged for putting out of or into operation a machine;

FIGURES 3 and 4 show a side view of a circuit breaker in accordance With the invention, which is adapted to be used in a circuit according to the FIG- URES 1 and 2, the circuit breaker position shown in these figures corresponding to the circuit positions schematically represented in the FIGURES 1 and 2, respectively;

FIGURE 5 shows a side view of a circuit breaker in accordance with the invention, which is adapted to break a current at full load; and

FIGURE 6 shows a side view of a circuit breaker in accordance with the invention, adapted for very heavy currents, which circuit breaker, however, preferably should be opened only when the current is zero or very small.

IN FIGURES l and 2 the numerals 10 and 11 indicate two conductors which belong to a circuit of a direct current system, in which current may be put several electrical machines, such as the direct current machine 12.

As long as the machine 12 is not put in the circuit a switch 13 is closed, whereas a switch 14, arranged for connecting the conductors 15 and 16 connected to the machine 12, is also closed. A switch 17 is provided between the conductors 10 and 15 and a switch 13 is provided between the conductors 11 and 16. When putting the machine 12 in the circuit these switches 17 and 18 are to be closed, while the machine 12 is running in no-load condition and the switches 13 and 14 are still closed. Thereafter, sequentially first the switch 13 and then the switch 14 should be opened. The machine 12 will be part of the circuit as shown in FIGURE 2.

Taking the machine 12 out of the circuit is obtained by closing the switches 13 and 14 and thereupon opening the switches 17 and 18. The position shown in FIG- URE 1 again prevails.

The switch or circuit breaker, according to the teachings of this invention, shown in the FIGURES 3 and 4 in two different working positions, has four fixedly arranged conductor blocks or strips 20, 21, 22 and 23, which correspond with the conductors 10, 11, 15 and 16, respectively in the FIGURES 1 and 2. The blocks 20 and 21 are arranged to be conductively connected one to the other by a set of conductive roller contacts 24 pivotally mounted on an offset shaft 25 and pressed against the contact surfaces 28 and 29 of the blocks 20 and 21 by means of a spring 26, which in turn is mounted around 3 a leading pin 27. At the place of the contact surfaces the blocks are provided with inserts 30 and 31 of a highly conductive contact material, e.g. silver, etc. The roller contacts 24 also can be made of a highly conductive contact material, at least on the circumference of the cylinder.

In the thickened end or spring seat 32 of the leading pin 27 against which end or seat is resting one end of the spring 2s, the offset shaft 25 is mounted. The other end of the pin 27 is slidably mounted or arranged for sliding in a leading block or guide 33 and is provided with a retainer nut 34. The leading block or guide 33 is provided with a mounting pin 35, which is arranged for rotation, i.e. pivotally mounted, in an insulating disc 36. The disc 36 and a cam 37 are rigidly connected to or mounted on a rotatably arranged control shaft 38. The cam 37 is arranged for cooperation with a tumbler or cam follower 39 rotatably mounted on a fixed shaft 40.

The tumbler or cam follower 33 carries a contact piece 41, which is electrically connected to the conductor block 23 by means of a resilient conductor and which rests against a contact piece 42 on the block 22. In the position of the switch or circuit breaker shown in FIGURE 3 the block 29 is electrically connected to the block 21 by means of the set of roller contacts 24 and the block 22 is electrically connected to the block 23 by means of the contact pieces 41 and 42. This arrangement corresponds to the closed position of the switches 13 and 14 in FIG- URE 1.

In the same manner as it is carrying the leading block or guide 33 the disc 36 carries two further leading blocks or guides 43 and 44, and, in the same manner as the leading block 33 guides the set of roller contacts 24, the leading blocks 43 and 44 guide the sets of roller contacts 45 and 46, respectively. In the position shown in FIGURE 1 the roller contacts 45 and 46 are free from the blocks 20, 22 and 21, 23, respectively. When the control shaft 38 is brought by rotation to the position shown in FIGURE 4, the roller contacts 45 and 46 are first pressed against the contact surfaces of the blocks 20, 22 and 21, 23, respectively, then the roller contacts 24 are withdrawn and finally the contact piece 41 is moved away from the contact piece 42. A current flowing through these contact pieces may give rise to an arc, which can be extinguished in any manner known to those skilled in the art.

Two contact surfaces such as 28 and 29, cooperating with one set of roller contacts such as the set of roller contacts 24, are in a substantially perpendicular spatial relation one with regard to the other. At the side of each contact surface a bearing stop or support member, such as the member 47, is present, which member is adapted to support the roller contacts when the same are not pressed against the contact surfaces. The angle over which the control shaft 38 is rotatable is limited by members not shown in the drawing. The two positions of the shaft 38 shown in the FIGURES 3 and 4 are the two extreme positions of the same. The shaft 38 may be rotated manually or by other means well known to those skilled in the art.

A second embodiment of the circuit breaker in accordance with the teachings of this invention is shown in FIGURE and is provided with blocks 50, 51, 52 and 53 which substantially correspond with the blocks 20, 21, 22 and 23 in FIGURE 3. The blocks 50 and 53 are, however, connected by a heavy metal strip 54. As shown in FIGURE 5 these three elements may constitute one single casting. In the same way the blocks 51 and 52 are connected by a strip of metal 55.

The strips 54 and 55 are separated by a distance in the axial direction of the control shaft 56 that between these strips there is room for a disc 57 corresponding to the disc 36 in FIGURE 3. The disc 57 carries members corresponding to the members carried by the disc 36 and particularly it carries sets of roller contacts 53, 59 and 60 and a cam 61, the latter being adapted to operatively close the contact piece 62 against the contact piece 63 in a first position and, in another position keeping the contact piece 62 at a distance from the contact piece 63 in the same manner as shown in FIGURE 3 wherein the cam 37 controls the contact piece 41. However, the guide or leading blocks of the apparatus in FIGURE 5 are rotatably mounted on the periphery of the disc 57 at diflerent points than shown in FIGURE 3 so that rotation of the control shaft 56 in a certain direction causes roller contacts 53, 59 and 60 to meet the blocks 50, 51, 52 and 53 substantially at the same moment. Upon rotation of the control shaft 56 in the opposite direction the roller contacts will leave the contact surfaces of the blocks first and thereafter the contact piece 62 will move, so that only the contact pieces 62 and 63 are interrupting a current of considerable size.

The strips 54 and 55 are mounted upon or are supporting the shaft 56 in a manner so that each element is insulated from the other. For example, the strip 55 is mounted on the shaft 56 with an insulating bushing 64.

A third embodiment of the circuit breaker according to the teachings of this invention is shown in FIGURE 6 and varies from the embodiment shown in FIGURE 5 only in the use of four sets of roller contacts 66, 67, 68 and 69. These sets of roller contacts are arranged as shown in the manner described above for connecting electrically the blocks 70, 71, 72 and 73 pairwise near the angular points of a square. Opposite blocks are already connected by the strips 74 and 75. Upon rotation of the control shaft 76 all the sets of roller contacts will come into contact with the contact surfaces on the adjacent blocks substantially at the same moment. The circuit breaker shown in FIGURE 6 is adapted to carry very heavy currents, however, it is not as satisfactory for the breaking of a circuit under conditions in which a considerable volt age might appear as the apparatus shown in FIGURES 3, 4 and 5.

Thus, there is disclosed circuit breaker apparatus which is rugged, reliable and yet simple in design and construction. Further, the circuit breaker apparatus described herein allows multiple, heavy duty switching without occupying a large area.

In conclusion, it is pointed out that while the illustrated examples constitute practical embodiments of the invention, it is not intended that the invention be limited to the exact details shown since modification of the same may be made without departing from the spirit and scope of the teachings of this invention.

Having described the invention, I claim:

1. In a circuit breaker, in combination; four substantially strip shaped conductors arranged substantially in a square; each conductor having at least one contact surface arranged in a substantially mutually perpendicular spatial relation with a contact surface of one of the other of said conductors; a plurality of roller contacts adapted to selectively conductively connect predetermined pairs of said conductors at said contact surfaces; each roller contact being mounted on an offset shaft; a spring for each roller contact adapted to apply pressure to said shaft in a direction perpendicular to the axial direction of said shaft to provide contact pressure; a rotatable control shaft adapted to control the movement of said roller contacts.

2. A circuit breaker according to claim 1 wherein two substantially parallel conductors are mutually connected by a substantially strip shaped connecting member.

3. A circuit breaker according to claim 1 wherein each pair of parallel conductors comprising the sides of said square is mutually connected by a substantially strip shaped connecting member.

4. A circuit breaker according to claim 3 wherein said strip shaped connecting members are journaled on said rotatable control shaft by insulating bushing means.

5. In a circuit breaker, in combination; four conductors; each conductor having at least one contact surface arranged in a substantially mutually perpendicular spatial relation with a contact surface of one of the other of said conductors; a plurality of roller contacts adapted to selectively conductively connect predetermined pairs of said conductors at said contact surfaces; each roller contact being mounted on an ofiset shaft; a spring for each roller contact adapted to apply pressure to said shaft in a direc tion perpendicular to the axial direction of said shaft to provide cont-act pressure; one of two adjacent conductors of said four conductors having a fixed contact piece; the other of said two adjacent conductors having a movable contact piece; and a cam mounted on said control shaft adapted to control said movable contact piece.

References Cited in the file of this patent UNITED STATES PATENTS Thomson July 4, 1893 Spangler Feb. 13, 1917 Kirkland Apr. 24, 1917 Richter Nov. 2, 1920 Evans July 4, 1933 Graybill Apr. 24, 1956 FOREIGN PATENTS Italy Apr. 21, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2 988 605 June 13 1961 Willem van Gent It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 36 strike out "and" second occurrence; column 2 llne 43 for "current",, second occurrence read circuit Signed and sealed this 12th day of December 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents USCOMM-DC UNITED STATES PATENT-OFFICE CERTIFICATE OF CORRECTION Patent No, '2 988 605 June 13 1961 Willem van Gent It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read :as corrected below,

Column 1 line 36, strike out "and second occurrence; column 2 line 4L3 for "current",, second occurrence read circuit Signed and sealed this 12th day of December 1961.,

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents USCOMM-DC

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