US2430367A - Alternating current power switch - Google Patents

Description

Nov. 4, 1947. R. PUDELKO EI'AL 2,430,357

ALTERNATING CURRENT POWER SWITCH Filed Oct. 1, 1942 2 Sheets-Sheet l Nov. 4, 1947.- R. PUDI ELKO ETAL ALTERNATING CURRENT POWER SWITCH Filed Oct. 1, 1942 2 Sheets-Sheet 2 Patented Nov. 4, 1947 ALTERNATING CURRENT POWER SWITCH Richard Pudelko, Hans Meier, and Werner Zingg, Zug, Switzerland, assignors to Landis & Gyr, A. G., Zug, Switzerland, a corporation of Switzerland Application October 1, 1942, Serial No. 460,356 In Switzerland November 13, 1941 10 Claims. 1

The present invention relates to an alternating current power switch, and more particularly to automatic electric switches, remote switches or the like for switching-on and off i1lumination-, heatand power current-circuits controlled by separate apparatuses such as time-switches, electric contact instruments, temperature regulators, relays, gas-, steamand water-measuring implements for pressure, temperature, water level, or press-buttons for manual attendance, etc.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means or the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations, and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

It is the object of the present invention to provide an improved motor driven electric switch in which the contacts are relatively slowly opened but are closed relatively swiftly.

Of the drawings:

Fig. l is a perspective View of a typical and illustrative embodiment of the invention, the switch being shown in open position;

Fig. 1a is a perspective view of certain parts of the switch shown in Fig. 1, the members being shown in the position shortly before the contacts are closed;

Fig. 2 is a perspective view of a modified embodiment of the invention; and

Fig. 3 is a perspective view of a further modifled embodiment of the invention.

The invention deals with the switching-on and ofi conditions of the main contacts of such switches as have been mentioned for higher current intensities, in particular those above 30 amp. Whereas the switch gears of switches of the kind mentioned have hitherto been built so that either the switching-on and oil? movement was immediate or both movements were retarded, the alternating current power switch according to this invention is distinguished by the fact that the switch gear is devised for performing a rapid closing movement and. a slower opening movement of the main contacts. The closing movement can be preferably carried out on the one 2 hand by a gearing means and a catch-work controlled by it, whereas on the other hand the opening movement of the main contacts isexeouted positively and immediately by the gearing means.

The sudden closing of the main contacts proves to be especially advantageous when silver contacts are utilized for A. C. switches of the kind, inasmuch as it is performed almost free from voltaic arc and without sticking concomitants, thu entailing only a. slight consumption of the contacts if by suitable dispositions in the switch gear a baille-free closing is cared for. In contrast thereto the retarded switching-on is disadvantageous as it causes a heavy consumption of the contacts and when incandescent lamps are switched-in the contacts are welded due to the heavy switching-in current. Unevenness caused, for instance, by molten drops can produce an electric arc which lasts until the contacts are completely closed and further contact material may thereby melt and be consumed.

There is an optimum switching-off speed. If the switching-off is too slow or too rapid, in relation to the moment of breaking the contacts with respect to the-A. C. curve pertaining thereto, heavy sparks may arise. With currents of 30400 amp. big electric arcs and a loud noise'are produced. Big voltaic arcs, however, require likewise big dimensions in the switch if flashing over is to be avoided. To a given switching-off speed representing the optimum just mentioned there corresponds a minimum of sparking.

According to the invention the switching-in speed is of the order of over 20 cm./sec., whereas the most favourable switching-off speed with an A, C. frequency of 50 cycles/sec. lies within the limits of about 0.5-1 cm./sec.

Common to all the three forms of embodiment of the present invention is the fact that they utilize an auxiliary force in the form of a Ferraris motor I driving by way of a suitable gear a cam member 5 tensioning and detensioning a catchwork 4, 4a, 6 and 8 which actuates the main contacts 3 and I to be switched on and off. Upon tensioning the catch-work the contacts 3 and 1 are opened by the run of the motor in positive motion corresponding to the optimum Of the switching-oil speed, whereas the releasing from tension of the catch-work suddenly closes the contacts.

According to the embodiment illustrated in Fig. l a plate la has secured to it a stationary touchcontact 1 arranged opposite a movable key-contact 3 mounted on a leaf spring 6 which is attached at one end to the plate l'a as shown by illustration, whereas its free end bears on the edge of a strap 4 fitted with a lever arm 4a with which it is oscillatably arranged on a support set up on plate Ta. At the upper part of the lever arm la is a roller 4?) and a rest 40. The contact spring 6 depresses the contact lever 4, 4a, whereby the roller ib normally bears against the circumference of the catchwork controlling member designed as eccentric 5 and driven by motor I. The catch-work comprises the contact spring 5, the contact lever 4, 4a and an angle lever B pivotally supported by a rigid shaft; the upper arm 8a of said lever can engage with a cranked portion the rest 40 of the contact lever 4, 4a, whereas the lower arm 8?) projects into the path of a pin 5a fixed on an eccentric 5. The spring 80 tends constantly to press the angle lever 8 against the lever arm 4a.

The controlling eccentric 5 is keyed on shaft M on which an arm 11 is rigidly secured. Further, for forming a slipping coupling on the shaft I4 a gear wheel 9 is arranged thereon frictiontight by the slipping disk 9a. The wheel 9 engages a piniOn 9b on the axis of the driving disk I a of the motor I. On plate l8 a pin I9 is provided projecting into the path of the arm I? rigidly mounted on the shaft, Finally, on the shaft hi there is a storage spring II] the one end of which being attached to the shaft, th other end fixed in the plate I8.

The action of this device is as follows:

In Fig. 1 the parts are represented in the position corresponding to the open contacts 3 and 1. If the switch is to be switched-on, i. e., the contacts 3 and I closed, the motor current-circuit is switched-in by hand or some suitable controlling apparatus; the motor is started and its driving disk Ia revolved in the direction indicated by the arrow P. Thereby the shaft l4 rotates so far in the direction of the arrow P1 through pinion 9b and friction-wheel 9 until the arm I! of the shaft M has almost completed one revolution. By this the storage spring H] has been tensioned.

During this revolution the eccentric 5 has revolved in the same direction as the shaft l4, whereby the front face Of the eccentric 5 which touches the roller 4b of lever 4a leaves the roller 41) and the pin 5a of the eccentric 5 comes into the vicinity of the lower arm 81) of the angle lever B. The

arm ll of the shaft now stands close to the position in which the storage spring I8 is tensioned. Upon further revolving the pin 5a of the eccentric 5 presses against the lower arm of the angle lever 8, rocks it contrary to the action of the spring So, so that it drops with its nose out of the rest 40, whereby the contact lever 4, 4a falls due to its gravity and the pressure of the contact spring 6. This causes the sudden closing of the key-contacts 3 and 7.

The switched-in position of the contacts 3 and I is maintained as long as the motor is under voltage, i. e., as long as the voltage does not drop below a prescribed minimum measure. Should the motor voltage sink below the respective minimum measure or fail entirely, then the torque of the storage spring 10 outweights that of the motor so that now the shaft l4 upon releasing of the spring i8 is moved backwards in the direction of arrow P2. The contact lever 4, 4a resting in the closed position of the contacts with the roller 42) on the eccentric 5 is now raised with the rotation of the shaft E 4 till the nose 8a of the angle lever 8 engages the rest 4:: of the lever do, during which movement the contacts 3 and I are opened and the catch-work simultaneously tensioned afresh. As the motor disk must be carried along with the comparatively big inertia effect and, in addition the other conditions ma be also selected at will, the desired slow opening movement of the contacts ensues. With the backward motion of the shaft M causing the opening of the contacts the flying mass (driving disk la, wheel 9, lever ll, eccentric 5) is braked by the impinging of the lever I! on pin l9 (Fig. l) by means of the friction coupling 9, So, so that injurious jerking sheets are avoided.

In the example shown in Fig. 2 the switch is connected in alternate switching with a controlling apparatus 20. In addition, the drive of the controlling member 5 for the catch-work is ac complished by way of an intermediate device which, driven by the motor l, prevents the contacts from sticking in an intermediate position between the switched-on and off position for any reason, such as voltage failure in the network and consequently giving rise to sparking and other injuries to the switch.

In this form of embodiment the main contacts 3 and l are again arranged and designed in the manner already described with reference to the first design. The contact lever 4, 4a cooperates here with an arm 5 as controlling member attached on the shaft 14 and provided with two rollers 5a, 5b. Further, the shaft I l carries the wheel l3a loosely mounted thereon which is part of a gearing set 13 leading to the driving disk m of the motor l. At the other end of the shaft M a curved disk in the shape of two superimposed hearts I! is fixed thereon with the rests 92c and 12d against which two pivotally supported rollers lie, it?) on two lever arms 12a, lZb bear by means of the spring 2! connecting both levers l2a, 2b. The curved disk 1 i has attached to it a pin which can cooperate with a pin 23 on the loose wheel Ba in the way described further below.

lvioreovcr, on shaft (4 a contact cam 24 is arranged adapted to engage the contact spring 2%; for the double contact 25, 25. The contact springs 24a, 25a and 25a are, as diagrammatically represented, connected to the outside mains through the control switch 23 and the motor 5.

The action is now as follows:

Fig. 2 illustrates the position for initiating the switching-01f or switching-on performance of the main contacts 3 and I. When on the control apparatus 22 th contact is shifted to a, voltage is passed via contact 25 to the motor which drives through the gearing [3 the wheel l3a in the direction indicated by the arrow. The wheel l3a pushes with its pin 23 against the pin 22 of the superimposed hearts i I, revolving this and hence the shaft i l in the direction of the arrow P3, whereby the rollers Ila, lib run up the heart curves and the spring 2! becomes tensioned. During the first turn of the roller 5b of the arm 5 raises the lever 4a according to the vel city predetermined by the gear, whereby the contacts 3 and I are opened comparatively slowly and evenly. Upon further movement of the heart I l that is to say after its top (upper point) has reached the roller Hit, it snaps further with quick motion due to detensioning or the sprin 2! until the roller i to falls into the rest l 20 and the roller 5 it) into the rest lZd. Upon this further rotation of 99 the lever 4 has fallen from the roller Eb onto roller 5a (of. the dotted position of the arm 5 and of the contact lever 4, 4a), Up to now the shaft M has turned through The contact spring 24a has hereby arrived on the lowest point of the cam 24 and broken the contact 25 and consequently the motor current-circuit. Contrary to the design shown in Fig. 1 in which the motor I is alive even in the ofi-position of the switch, the motor is disconnected in this case immediately after opening the contacts 3 and I, i. e., after the switching performance.

When the switch has now to be switched-on, i. e., the contacts 3 and 1 closed, the contact is set to b in the control apparatus 2%. As in this position of the shaft or the cam 24 the contact spring 24a still closes the contact 26, the motor current-circuit is again alive; the motor starts and turns the double heart H further in the aforementioned manner in the direction of the arrow P3, whereby the contact lever 4, flea-shown in the dotted positioin drops from the rolleria of the steering member 5 and thus the contacts 3 and "l are instantaneously closed. The double heart II is now at the end of the third 90-turn; the cam 24 then cuts out the contact 26 through the contact spring 24a and with it the motor current-circuit. The accomplishment of the com plete revolution of the shaft and of the controlling member 5, respectively, into the position as drawn out in solid lines in Fig. 2 is brought about by the device I i.

The use of the intermediate device ll for con trolling the shaft i4 makes it possible that, when in an intermediate position of the con acts the driving motor goes dead for any reason, the device is not set quiescent in this position but resumes one corresponding to the switched-on or On condition. If, for instance, starting from the position as shown in Fig. 2, the superimposed heart H has turned through 50", the contacts 3 and I are already slightly opened. Should now the mo" tor I not be alive, the steering member 5 guiding the contact lever 4, 4a with the contact 3 does not remain in this position, in which a permanent spark might occur between. the contacts 3 and "I, as the spring 2! by means of the rollers lo, I lb thrusts the double-heart H back again into the illustrated initial position, i. e., into the switched-on position. Similarly, the controlling device ll functions in other intermediate positions, in which the motor, unintentionally, stands still.

With the described loose connection between the pinion He and the double-heart l I, the latter r and consequently the shaft I4 performs two slow movements in the course of one revolution corresponding to its curve guidance (running up of the curves on the rollers Ila, Nb) and two quick movements (running off of the curves on the rollers).

In order to ensure an even running off of the shaft l4 and therewith of the controlling member 5, the pinion lea may either be rigidly mounted on the shaft M or, e. g., the pins 22 and 23 screwed together. In doing so, a retarded, i. e., even revolution of the shaft I4 is obtained, whereby the gearing set IS with the driving disk la of the motor 1 serves as a retardation medium or check.

Fig. 3 illustrates an actual retardation device by mechanical back coupling of the controlling member 5 with the motor l. Here, too, we have a power switch alternately connected to a control apparatus 25! such as shown in Fig. 2. In this embodiment, too, the motor runs invariably in the same direction as with the switch according to Fig. 2. It is similar also with respect to the controlling of shaft l4 by a superimposed heart similarly equipped and designed as the switch on Fig. 2. With this retardation deviceasin the embodiment in Fig. 2 with retardati0na lever 5 with a roller 5a suffices as controlling member for the catch-work. Through the retardation device, more fully described below, the run of the controlling member 5 is governed in such a way that a second roller, as, in the example according to Fig. 2 without retardation, is dispensed with.

- The retardation device according to Fig, 3 comprises in addition to the loosely mounted wheel I3a of the normal gear drive between motor I. and shaft I4 another wheel lSa riding on shaft M. This wheel, however is rigidly supported thereon and associated with a set of wheels lEc, id and and IE6 arranged on the shaft l3b. The wheel [to is keyed on the shaft l3b, whereas the rigidly connected together wheels Hid, lBe are loosely mounted thereon. The wheel I has a pawl 21 which engages the ratchet wheel I611.

The action of the device in Fig. 3 is substantially the same as that of the retardation device in Fig. 2. Upon rotation of the double-heart curve H in the direction of the arrow P3 the two rapid movements of the shaft-when the rollers run off On the double-heart curves-are checked by the gear Ida-[6c as the wheels l6a, We and Mid and consequently the shaft is coupled throughthe pawl 21 with the gear set I3 of the motor I whereby the desired check or drag, i. e., the smooth running of the shaft I4 is attained.

In the illustrated forms of embodiment only one contact pair 3 and I is'shoWn. Obviously, the present invention may likewise be applied in connection with multipolar switches.

Each single phase is preferably provided with a separate spark chamber covered to the top. The covering, however, must not be a through one, but must be carried out phase for phase so that possible metal precipitations derived from the contacts cannot constitute conductive connections between the single phases.

Furthermore, there is a possibility offered within the scope of the invention of providing the switch so that it is-upon closing the motor circuitcapable to switch-in, sever or commutate.

While we have described certain specific embodiments of our invention it is to be understood that the details of construction may be changed by those skilled in the art within the purview of the appended claims.

We claim:

1. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, a shaft adapted to be drvien thereby, a resilient element connected to one contact and adapted to be tensioned while the contacts are moved. slowly apart, control means disposed between the shaft and resilient element and adapted to be operated by the shaft for a control action to tension the resilient element and hold it tensioned and the contacts separated for a predetermined period and adapted to be operated by the shaft for a second control action to release said element and allow the contacts to be brought together thereby, and energy storing means rendered operative for action when the motor is en ergized for subsequently driving the shaft to effect the first-named control action when the motor is deenergized.

2. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, a shaft adapted to be driven thereby, a resilient element connected to one contact and ad pte to be tensioned while the contacts are moved slowly apart, cam operated control means adapted to be actuated by the shaft for a control action to tension said element and hold the same tensioned and the contacts separated for a predetermined period and adapted to be actuated by the shaft for a second control action to release said element and allow the contacts to be brought together thereby, and a motor spring, tensioned for action when the shaft is driven by the motor for subsequently driving the shaft to effect the first-named control action when the motor is deenergized.

3. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, a shaft adapted to be driven thereby, a leaf spring element connected to one contact and adapted to be tensioned while the contacts are moved slowly apart, control means adapted to be operated b the shaft for a control action to tension the leaf spring element and hold it tensioned and the contacts open for a predetermined period and adapted to be operated by the shaft for a second control action to release said element and allow the contacts to be brought together thereby, and energy storing means rendered operative for action when the motor is energized for subsequently driving the shaft to effect the first-named control action when the motor is deenergized.

4. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, a shaft adapted to be driven thereby, a leaf spring element connected to one contact and adapted to be tensioned while slowly moving the said contact away from the other contact, cam operated control means adapted to be actuated by the shaft for a control action to tension said leaf spring element and hold the same tensioned and the contacts separated for a predetermined period and adapted to be actuated by the shaft for a second control action to release said element and allow the contacts to be brought together thereby, and a motor spring energized by the shaft in its aforesaid operation by the motor for subsequently driving the shaft to effect the first-named control action when the motor is deenergized.

5. A motor actuated electric switch comprising, in combination, a pair of contacts, a tension de vice for moving one contact toward the other contact, a motor, control means disposed between the motor and tension device operative for a control action to simultaneously tension said tension device and move the contacts slowly apart and hold the same from movement and operative for a second control action to release said tension device for movement and action to bring the contacts rapidily together, and energy storing means coacting with and governed by and governing the motor and acting on said control means for effecting said first-named control action to separate the contacts when the motor is deenergized,

6. A motor actuated electric switch comprising, in combination, a pair of contacts, a tension device for moving one contact toward the other contact, a motor, control means arranged between the motor and the tension device and operative for a control action to simultaneously tension the tension device and slowly move the contacts apart and hold the same from movement and operative for a second control action to release the tension device for action and allow 8 the contacts to be brought together thereby, and means controlled by the motor and governing said control means for effecting said secondnamed control action,

7. A motor actuated electric switch compris ing, in combination, a pair of contacts, an electric motor, and control means between the electric motor and contacts for moving the contacts apart relatively slowly and for movin the contacts together relatively swiftly comprisin spring means carrying one of said contacts and normally urging said contacts together, a lever for tensioning and releasing said spring means from tension, cam means engaging said lever for tensioning the spring means and moving said contacts apart, catch means engageable with said lever to hold the contacts in spaced apart relationship and operable by the cam means to release said lever to allow the spring means to close the contacts when the motor is energized, and a spring operatively connected with and tensioned when the motor is energized and acting, when the motor is deenergized, to actuate said cam means and the lever engaged thereby, for tensioning said spring means and thereby separating the contacts,

8. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, and driving means between the motor and contacts for moving the contacts apart relatively slowly and moving the contacts together relatively swiftly by power from the motor, said means comprising spring means carrying one of said contacts and urging said contacts together, cam means for moving said contacts apart and ten sioning said spring means, an energy storing spring operatively connected with and tensioned when the motor is energized and acting, when the motor is deenergized, to actuate said cam means for tensioning said spring means and thereby separating the contacts, catch means for holdin said spring means inactive but in tensioned position and maintaining said contacts in spaced apart relationship, and means including said cam means actuated by said motor when the motor is energized for tensioning said energ storing spring and tripping said catch means for releasing said spring means from tension and thereby closing the contacts.

9. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, spring means carrying one of said contacts and normally urging said contacts together, cam means for tensioning said spring means and movin said contacts apart, latching means for maintaining said spring means under tension and said contacts in spaced apart relation, control means including said cam means actuated by the motor when the motor is energized for tripping said latching means whereby the spring means are released from tension and the contacts moved together thereby, and other spring means tensioned when said control means are driven by the energized motor and released from tension to return said cam means to an initial position when the motor is deenergized.

10. A motor actuated electric switch comprising, in combination, a pair of contacts, a motor, spring means urging said contacts together, a cam for tensioning said spring means and moving said contacts apart and for releasing said spring means from tension to allow said contacts to be moved together thereby, and means for controlling said cam means from the motor to bring the contacts together when the motor is energized and then stall the motor and tension 9 10 said spring means and thereby separate the con- UNITED STATES PATENTS tacts when the motor is deenergized.

R H PUDELKO Number Name Date HANS MEIER, 47,071 Besag July 20, 1915 WERNER ZINGG, 5 ,1 ,41 Skinner Aug. 11, 1914 1,272,445 Holliday July 16, 1918 REFERENCES CITED 2,083,425 Beusch June 8, 1937 The following references are of record in the file of this patent:

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