US2435027A

US2435027A - Pointer-controlled, periodic circuit breaker

Info

Publication number: US2435027A
Authority: US
Inventors: Blomberg Knut Hugo
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 1941-10-21
Filing date: 1942-10-21
Publication date: 1948-01-27
Anticipated expiration: 1965-01-27

Description

Jan. 27, 1948. K. H. BLOMBERG 2,435,027

POINTER-CONTROLLED, PE-RIODIC cmouxf BREAKER Filed Oct. 21, 1942 2 Sheets-Sheet 1 Fig. 2

INVENTOR L2 BY K.H.BLOP1BERG AT Tm}.

Jan. 27, 1948. K. H. BLOMBERG 2,435,027

POINTER-CONTROLLED, PERIODIC CIRCUIT BREAKER Filed on. 21, 1942 2 Sheets-Sheet 2 Fig. 3

INVENTOR Bx K-H-BLQMBERCT "qwasw q WW! Patented Jan. 27, 1948 POINTER-CONTROLLED, PERIODIC CIRCUIT BREAKER Knut Hugo Blomberg, Appelviken, Sweden, as-

sig'nor to Telefonaktiebolaget L. M. Ericsson, Stockholm, Sweden, a company of Sweden Application October 21, 1942, Serial No. 462,868 In Sweden October 21, 1941 2 Claims. (01. 175-373) The present invention relates to an automatic electric arrangement for control of a circuit in dependence upon the position of a pointer in a measuring instrument. Such arrangements are used among other things forthe control of the temperature in electric furnaces. The object of the invention is to produce a controlling apparatus of such a type that is simple and cheap and in which'the pointer of the measuring instrument is not exposed to mechanical stresses.

The invention will be more closely described with reference to the accompanying drawings in which Fig. 1 is a perspective view of a device according to the invention, Fig. 2 is a circuit diagram, Figs. 3 and 4 show the contact spring assembly with the springs in different positions.

On a pivot l is placed a U-shaped arm 2 which I at the one end supports a relay 3 and at the other is formed as a pointer 4 that is movable over a scale 5. The arm 2 is adjustable in different positions by turning round the pivot I which turning is produced by the wheel I actuating a toothed gear segment 6. The measuring instrument 8 is arranged in such a way that the axis of driving axle 9 of the pointer coincides with the axis of the pivot l. The pointer axle supports the pointer In, the prolongation H of which cooperates with one, l5, of the two spring assemblies I4 and i5 of the relay 3. The contacts Na and Nb of the spring assembly I4 are closed when the relay is in its rest position but are opened when the armature l6 of the relay is attracted by a stud on the armature lifting spring llb. The spring assembly IS, the construction of which appears from the Figs. 1, 3 and 4, comprises two contact springs l9 and 28. The latter is furnished with a reinforcement 21 and studs l8 and 22. The-spring I9 is provided with a stud 28. Above the contact is arranged a stationary bridge 2'! provided with a track 32 adapted, at times. to receive the stud 28. When the armature I8 is attracted and presses the stud II the springs 28 and I9 are lifted, the latter by meansof the stud 22. A closing of the contact between these springs cannot occur if the movement upwards of the spring I9 is not limited. This closing is however effected in the position shown in Figs. 3 and 4 when the pointer prolongation ll takes such a position that it lies across and obstructs the track 32. When the two springs l8 and are then lifted, the stud 28 of the spring is can not penetrate into the track 32. The movement upwards of the spring lfl' will therefore be stopped as soon as the stud 28 engages the prolongation I l. During the continued movement of the armature only the spring 20 will be lifted upwards and. in so doing it makes contact with the spring l9 as shown in Fig. 4. If the prolongation H assumes a position laterally of the spring assembly as shown in Fig. 1

with dotted lines, the track 32 will be open and:

the stud 28 will pushinto the track when the springs are being lifted. The two springs will then be lifted parallel to each other during the whole movement of the armature and there will be no contact between them. In order to prevent the stud 28 from striking and pressing hard against the pointer if the pointer prolongation H is just in front of the track 32 there is a spring 25, Fig. 3, which is furnished with a stud 24. The spring is bent at its free end in such a way that a surface 28 facing the pointer prolongation is obtained. The spring is also furnished with a flap 26 for limiting the movements of the pointer in one direction, Fig. 1. n opening 3|, Fig. 1, is arranged in the same spring 25 in such a way that the stud 28 is able to move freely therein. When the

contact springs

18, 28 are beinglifted at the movements of the armaturethe'spring- 25.will also be lifted upwards by the studs 22 and stud 24. The surface 29 then will make .contact'with the pointer prolongation H.

' During: the "continued movement upwardsof the armature the, free end of the. spring 25 will be bent adj'acentfthe stud 24 in such a way that it bears yieldably against 'the prolongation H as is shown in land presses the prolongation ll elastically'against-the bridge 21 before the stud 28 strikes against the-same. 1 g

Fig. 2 is a circuit diagram showing the inven' tion being applied to, an arrangement controlling the temperature in a furnace. M is ameasuring instrument. Both its terminals Tl are connected to a thermocouple in the furnace over the resistance R5. The mercury circuit breaker H is connected to a control circuitover the line T2, which circuit supervises the connectionanddisconnection of a'heater in the furnace. This heater will be connected when the circuit breaker. H takes the position shown in Fig. .2. The relay 3 is connected to the wires (1, b, over' the glow lamp G, the resistance R4 and the rectifier L2. The wires a, b are connected with an alternating current source. KI and K2 are condensers. The relay 3 is energized periodically in knownlmanner by means of the glow lamp G'and the condenser cult of the slow release relay R. Every time the relay I is energized the contact between the springs Ila and Ilb in the spring assembly ll of the relay will be broken and the two springs II and 20 will be lifted. In dependence upon the position of the pointer prolongation I I, the contact between I9 and 20 then will be broken or closed. If the pointer II is just in front of IS and 20, this implies that the right temperature in the furnace is obtained. As this temperature must not be exceeded the contact I9, 20 will be closed at the next momentary attraction of the relay R, whereby the slow release relay is ener gized and closes a holding circuit for itself over contacts r1, r2. After de-energization of the relay, said holding circuit is closed over the contact Ha, Mb. On attraction of the relay R the circuit breaker H will be operated, whereby the above described heater in the furnace will be disconnected. The heater will continue to be disconnected for as long a time as the temperature is at the value, which corresponds to the position of the pointer I I right in front of the springs I9, 20. In this position of the pointer the relay R, is energized. The relay R. will be energized also during the periodical energization of the relay 3 as the contact I9, 20 at every energization of the relay 3 will be closed at the same time as the contact Ila, Mb will be broken. If the temperature falls and the pointer thus will take such a position that it cannot co-operate with the springs I9, 20 the contact I9, 20 will not be closed at the next energization of the relay 3. Said contact remains broken and at the same time also the contact Ha, Ilb is being broken. The circuit of the relay R will therefore be broken and relay R, de-energized whereby the contact rI, r2 will be broken and the circuit breaker H restored to its rest position in which the heater is again connected. The temperature increases thereby again to a value corresponding to the pointer II coming right in front of the springs I9, 20 whereby the heater will then be disconnected as above described. It is evident that the heater will be alternately connected and disconnected. the temperature through the arrangement being thus maintained at a constant value.

I claim:

1. An automatic electric arrangement for the control of a circuit in dependence upon the position of a pointer movable over a scale of a measuring instrument comprising a contact spring assembly disposed in the path of movement of and controlled by said pointer, said assembly including contact springs for controlling said circuit, means for selectively setting said assembly along the path of movement of said pointer, a second circuit including a discharge tube and a condenser, and a relay periodically energized by said second circuit for operating the springs of the spring assembly in dependence upon the position of said pointer.

2. An arrangement as claimed in claim 1, wherein said second circuit also includes a variable resistance.

' KNUT HUGO BLOMBERG.

REFERENCES CITED The following references are of record in the file 'ofthis patent:

UNITED STATES PATENTS Number Name Date 2,101,452 Rauch Dec. 7, 1937 2,129,747 Sorensen Sept. 13, 1938 2,201,031 Eichelberg May 14, 1940 2,249,368 Weckerly July 15, 1941 2,249,369 Williams July 15, 1941