Патент USA US2133888код для вставки
Oct. 18, 1938. F_ G, BLQCH 2,133,888 ELECTRIC CIRCUIT ARRANGEMENT FOR CONTACT POINTER THERMOSTATS AND LIKE INSTRUMENTS Filed Jan. 10, 1935 A\ 747' 5 L . - , Z2 _ '1 Z: 19/; ? I Z? M 'a/Msrau/c 57-0,? 5) 1.9 B - M _ I‘ ' ' (n 3' hi‘ 6 h 14%? 1-9 THERMasMT A_\ /5 iv BIMETHLL/C’ STRIP.” [g B,_ ‘1*; D (k \[K -.II III I v . n ll 6 _ (1/ "5 H ‘m 7' MIVE/YI'O/i’; Fra 8); M Geo/:9 8/0 cl), M MM_ ' ' Patented on. 1a, 1938 " _ 2,133,888 UNITED STATES PATENT OFFICE 2,133,888 ELECTRIC CIRCUIT ARRANGEMENT FOR CONTACT-POINTER THERMOSTATS AND LIKE INSTRUMENTS Franz Georg Bloch, Leitmeritl, Clechoslovakia Application January 10, 1935, Serial No. 1,238 In Czechoslovakia January 10, 1034 4 Claims. This invention relates to an electric circuit ar- 5 10 15 29_ 25 30 Q 3 (Cl. 219-20) voltage occurs. With the arrangement of the rangement for thermostats having pointers present invention, on the contrary, only a slight adapted to act as contacts and for like instruments provided with a contact pointer and two adjustable contacts, and serving for the electrical control of temperatures, According to the present invention, the arrangement is such that when the pointer touches one contact a switching operation is initiated and continues until the pointer touches the other contact. The arrangement of the present invention differs fundamentally from the known arrangements in that both the making and the breaking of the circuit are eiiected by the closing of the contacts of the instrument, that is to say, the control operation is not ail’ected when one of the two contacts opens. On this account the slipping or sliding contacts in general use are not employed, these being known to possess considerable disadvantages, because the pressure needed to establish a slip contact imposes considerable demands on the torsional strength of the measuring unit, and the resulting friction leads to inaccurate and unreliable indications. It is also known that, in measuring instruments, slip and sliding contacts give rise to working troubles, also because parts of the track traversed by the con~ tact member are scorched due to the inevitable sparking, as a result of which the passage of the current is impeded. Moreover, slip and sliding change of voltage, if any, occurs in the circuit on the contacts being opened, and consequently, the burning of the contacts is very considerably reduced, and in some cases practically sup pressed. In the known circuit arrangements at tempts were made to reduce sparking by inter posing condensers between the contacts. Ap plicant has found that this increases the force required to separate the contacts for instantaneous interruption, applioant’s explanation being that the condensers cause the contacts to be loaded with 8 Static charge- Since this additional force can only be generated in measuring instruments by an increased initial voltage in the measuring unit. the pointer jumps when the contacts are opened, resulting in a considerable oscillation of the pointer and ?uctuation in the conttrol opera tion- For this reason an arrangement 0! this kind is unsuitable where accurate control is de sired, in which event there must be no jumping of the Pointer For this reason, such an arrangement is in applicable when accurate control is required and the pointer must not jump. According to the present invention, condensers are provided which serve, not for protecting the contacts of the in strument, but to prevent disturbance being set up by the installation, in order that the operat- contacts necessitate a complicated construction oft the instrument when the control is to be adjustable over the whole or a large portion of the scale, ‘ CA In the arrangement 01' the present invention, on the contrary, simple mutually insulated contact levers, with simple setting mechanism are arranged on the glass front of the instrument, enabling the adjustment to be made to any desired 40 point. Whereas, in all'the known circuit arrangements, the opening of the contacts is a major operation, it no longer plays any part in the arrangement of the present invention. It is known that opening the contacts is the main 45 cause of their premature wearing out, and the reason -for the unreliability of, present-day contact instruments. This is due to the destruction of the contacts by the considerable liberation of heat arising from sparking in breaking the cir59 cuit. The intensity of the sparking for a given current strength increases with the increase in voltage on the interruption of the current. In circuit arrangements in which the control operation is put into action by opening the contacts, 55 an alteration in the value of the main circuit I 10 145 20 25 30 ing of the contacts may not cause any incon venience to neighboring broadcast receptions and also protect the working contact. Since, on this account, the condensers do not lie parallel to the instrument contacts, the aforesaid inconveniences 35 also disappear. It is characteristic for the circuit arrangement that the temperature recorder or thermostat lies in series with the resistance of the relay. on Contact being made with the one limiting pointer, but parallel with the resistance 40 of the relay when in contact with the other limiting pointer. The value of the resistance can be so selected that the switching entails a mini mum of current consumption in the control cir cult, the invention accordingly also meeting prac- 45 tical requirements in respect of economy, and constituting, in technical respects, a considerable improvement in the sphere of arrangements for switching contact instruments by reason of its reliability, simplicity and ease of inspection. A 50 further advantage of the invention consists in that the pointer instrument can be set up sepa rately from the relay. Thus, the relay can be situated in the immediate vicinity of the current consumer, the heavy-current wire between them 55 2 _ 2,133,888 being unnecessary. Owing to the small control current, the wire connecting the instrument to pointer t1 touches the contact lever is. When the relay may be of small cross section. More over, in consequence of this local independence is as follows: of the two parts, complicated control operations also can be performed in a simple manner. In order more clearly to understand the in vention reference is made to the accompanying drawing, which illustrates by way of example, two 10 embodiments, thereof and in which Fig. 1 is a diagrammatic representation of one embodiment; and Fig. 2 shows a second embodiment. Both ?gures represent the circuit arrange 15 ment for an electric radiator, the control opera tion of which is assumed to keep the heat of a room within a given range of temperature. Ob viously, any other control operation could also be performed by means of said circuit arrange 20 ments, for example, the controlling of an elec tromotor driving a compressor, a pump, a fan, a valve, slide or the like. Moreover, a magnet or other electrical apparatus can be controlled instead of an electromotor. 25 In Fig. 1, A denotes the contact instrument or thermostat with the contact pointer t1 and the two contact levers 152 and fig. 18 denotes an elec tric switch unit, in the present case a thermo re lay, the heavy-current contact 7c of which is 30 mounted on a bimetallic strip and is actuated by the hot wire h and connects the electric radiator C across the main r—s, or switches it o? therefrom. Instead of a thermo relay, any other relay or a corresponding electric switch unit, may also be employed. The circuit ar rangement consists in connecting the two con tact levers t2 and is to separate lines, s or r of the electric mains, whilst the contact pointer h is connected to the resistance w. The other (Lil terminal of ‘an is connected at g to the hot wire h and the resistance 103. The second terminal of h is connected with the resistance wz, the sec t1—t2 are in contact, the course of the current The current from the line s ?ows through the closed contacts t1—tz and by way of the resist-' ance 7.01 to the terminal 9 where it divides. The heating current flows through h and we to the line 1‘. The other branch of the current ?ows from the terminal g through we and also to the line r. The resistances Z01, wz and we are so 10 calculated that su?icient current for heating the relay now ?ows through h. By this means, the contact k is closed, and a current now flows from the line 3 through the radiator C and to the line r. The heating of the room now pro ceeds and, in consequence, the contact pointer t1 moves towards the right, thus separating from the lever t2 and breaking the contact t1-—-t2. The path taken by the current in the control circuit 20 is now as follows: A current ?ows from s through the contact k, resistance wz, h and on to the line 1'. In this case also, the heating current is so calculated as to maintain the relay in the operative condi tion so that the radiator C continues to function. 25 Consequently, the temperature of the room con tinually increases until ?nally the contact pointer t1 touches the contact lever t3. In these cir cumstances a current ?ows from 1, through the contact t:—t1, the resistance 201 and w: and the 30 contact k to s. At the same time a current ?ows from 1', through 102, h, w; and k, to 8. How ever, the heating current now ?owing through h is so small that it can no longer maintain the relay in the operative condition, the contact is 35 being consequently interrupted and the radiator C disconnected from the main. The temperature of the room becomes cooler, and the contact pointer t1 moves away in the dead circuit from the lever t3. As the room becomes colder the contact pointer t1 bears against the contact le ver tz and the cycle recommences. Each of the ond terminal of- the latter being connected to the condensers 1n and 1.1.2 is connected with a contact line 1. lever and a line of the mains circuit and they serve chie?y for preventing disturbance to broad 45 The second terminal of wa is connected to the wire leading from the heavy-current ter minal through the radiator C to the line 1'. The second terminal of the heavy-current contact It leads to the line s. It is a characteristic feature of the arrange 50 ment of the present invention that the resistances are switched by thevplay of the contacts so that in all cases two resistances alternately are connected in parallel, one of which then serves as a joint series resistance, for example, 72 and 202 55 in the drawing being regarded as one resistance. Only when the contact pointer is open and the heavy-current contact closed, are the resistances wz and ‘an in series. The rational values of the resistances are a matter of simple calculation 60 so that switching requires a minimum consump tion of current in the control circuit, and there fore the arrangement of the present invention also satis?es practical requirements from the economic stand-point, whilst from the technical 65 point of view, its reliability, simplicity and ease of supervision represent a considerable improve ment in circuit arrangements for contact instru ments. When, for example, the contact lever is is set 70 on 8° of the scale, and the contact lever is on 27° of the scale, the control operation in the ex ample represented proceeds in such a manner that when the contact pointer t1 touches the contact 252, current is switched on to the radiator, 75 which latter is switched o? when the contact cast reception. In the embodiment shown in Fig. 2, the con tact tz, with the resistance an is applied to the line s, whilst the contact is is applied to the ter minal g of the energizing resistance h. The con 50 tact t1 is connected to the common terminal i of h and on, this latter being applied to the line 1'. The point g is in electrical connection with the terminal 112. of the resistance C. For the protection of the contact is, a condenser 55 u is provided in parallel therewith. In this ar rangement, the working operation is similar to that according to Fig. 1. 0n t1—t2 being closed, a current fiows through 101, and t2--t1 to the point i, where it divides. One branch of the current 60 ?ows through ‘L02, the other through h and the loading resistance C to the line T. The second branch current energizes the resistance h and closes the contact is, so that a working current now ?ows from the line 3, through k, m and C, 65 to the line 1'. Said working current also passes when the contact t1—tz is broken, because the re sistance h still remains energized by the current ?owing, from the line 7', through 102 and h, to g, and thence to m, by way of the contact is, to the 70 line s. On the contact t1—t3 being closed, h be comes dead, because the contact t1—t3 is now in parallel with h. By this means, the contact A: is opened and the working current interrupted. The relay may be housed in the interior of a 75 2, 188,888 3 cylindrical former on the outside of which the various resistances of the circuit arrangement are wound. By this means the relay is protected heater, a source of electric current, a thermostat having an angularly movable contact member re in a simple and reliable manner and also a sav sponsive to temperature changes, a graduated ing in space is eiiected in the construction of the temperature scale on said thermostat, contacts on said thermostat and adjustable along said apparatus. I claim: 1. In the controlling circuit for an electric cur rent consuming device, a source of electric cur 10 rent, a thermostat having an angularly movable contact member responsive to temperature changes, a graduated temperature scale on said thermostat, contacts on said thermostat and ad justable along said scale, connections between 15 said current consuming device and said source of electric current, a switch in one of said connec tions, a thermal relay operating said switch, con nections between said source and each of said adjustable thermostat contacts, a connection be 20 tween said movable contact member and said thermal relay, a current-limiting resistance in cluded in one of said connections, a connection between said thermal relay and one of said con nections to said current consuming device, and a 25 connection through a current-limiting resistance between said thermal relay and said source of electric current. 2. In the controlling circuit for an electric heater, a source of electric current. a thermostat having an angularly movable contact member responsive to temperature changes, a graduated temperature scale on said thermostat, contacts on said thermostat and adjustable along said scale, direct connections between said heater and said source 0! electric current, a switch in one of said connections, a thermal relay operating said switch, direct connections between said source and each or said adjustable thermostat contacts, a connection including a resistance between said movable contact member and one end or said thermal relay, a connection including a resist 3. In the controlling circuit for an electric scale, direct connections between said heater and said source of electric current, a switch in one of said connections, a thermal relay, operating said switch, a connection including a resistance be tween said source and one of said adjustable thermostat contacts, a connection between one end of said thermal relay and the other or said adjustable thermostat contacts, a connection be tween said movable contact member and the op 15 posite end 01' said thermal relay, a connection be tween the ?rst mentioned end of said thermal re lay and one of said connections to said heater, and a connection including a resistance between the opposite end of said thermal relay and said 20 source of electric current. 4. In the controlling circuit for an electric heater, a source of electric current, a thermostat having an angularly movable contact member re sponsive to temperature changes, a graduated 25 temperature scale on said thermostat, contacts on said thermostat and adjustable along said scale, direct connections between said heater and said source of electrtic current, a switch in one or said connections, a thermal relay operating 30 said switch, a connection including a resistance between said source and one of said adjustable thermostat contacts, a connection between one end oi’ said thermal relay and the other of said adjustable thermostat contacts, a connection be 35 tween said movable contact member and the op posite end of said thermal relay, a connection be tween the ilrst mentioned end of said thermal re lay and one oi.’ said connections to said heater, a connection including a resistance between the 40 opposite end of said thermal relay and said ance between the said end of said thermal relay and one oi’ said connections to said heater, and a source of electric current, and a condenser con nected on one side thereof to said source of elec connection including a resistance between the opposite end of said thermal relay and said source or electric current. tric current and on the other side to said heater in parallel with said switch. FRANZ GEORG BLOCH.