US2166163A

US2166163A - Electromagnetic relay

Info

Publication number: US2166163A
Application number: US91725A
Authority: US
Inventors: Carl H Larson
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-21
Filing date: 1936-07-21
Publication date: 1939-07-18
Anticipated expiration: 1956-07-18

Description

July 18, 1939. c. H. LARsoN ELECTROMAGNETIC RELAY Filed July 21, 1956 .Patented July 18, 1939 i UNITED STATES PATENT OFFICE n ELECTROMAGNETIC RELAY Carl H. Larson, Elkhart, Ind.

Application July 2l, 1936, Serial No. 91,725

14 Claims.

In relays heretofore known, and particularly in mechanical relays, it has been the practice, when a plurality of switches were to be operated from. the same magnetic circuit, to mount the several contacts on a common armature, so that all switches would act in unison. If the circuit controlled by any one pair of contacts required a time delay, those contacts were arranged to operate from an entirely different magnetic circuit,

l0 for the common way to eilect a time delay in a mechanical relay other than by clock work is to provide the iron circuit with a secondary closed winding.

'Ihe principal object of this invention isto provide an electro-magnetic relay in which fast acting and slow acting contacts may be associated with the same magnetic circuit, or with a plurality of magnetic circuits of equivalent characteristics, and in which the slow acting contacts need not necessarily have the same time delay characteristics.

Stated otherwise, it is the principal object oi the invention to provide an electro-magnetic relay in which a single magnetic circuit, or a plurality of magnetic circuits of equivalent characteristics, operate a plurality of contacts having an inilnite variety o! time delays including contacts which are immediately responsive to the flux set up through the magnetic circuit or circuits.

Other objects of the invention are to provide a relay which is cheap to manufacture, small in size, easy to adjust, and in which the contact elements may be readily replaced, if occasion demands.

Still flu'ther objects and advantages will become apparent as the disclosure proceeds'and the description is read in conjunction with the accompanying drawing, in which Fig. 1 is a plan view of the relay embodying this invention;

Fig. 2 is a vertical, sectional view on the line 2--2 oi' Fig. 1;

Fig. 3 is a sectional view taken on the line4 3--3 of Fig. 1, through the switch B, the switch parts being shown in the position which theyassume immediately after energization of the coil;

Fig. 4 shows the position of the parts of switch B immediately after the coil has been de-energized; and Y Fig. 5 shows, by way of illustration,-an electrical circuit associated with the relay.

It will be understood that this specic disclosure is by way of illustration only, and that the invention may be embodied in many other forms within the scope of the appended claims.

(CI. 20o-97) The relay shown inthe drawing comprises a coil III which has an axial opening II adapted to receive an iron core I2 which constitutes a part of the magnetic circuit operating switches A,

B and C. The magnetic circuit also includes top 5 and bottom pole pieces I3 and I4, respectively, each of which is segmental in form and has a hole I5 adapted to receive the reduced end of the core I2. The pole pieces are held in place by washers I6, secured by screws I1, threaded into 10 tapped holes in the core.

A pluralityl of alined apertures I8 and I9 are provided in the top and bottom pole pieces, respectively, to receive the switches A, B and C.

Pole sleeves 20 and 2i are iitted into the aper- 15 tures I3 and I3 to iix the position of the air gap 22 associated with each switch. Preferably a vertical split sleeve 23 of non-magnetic material, such as Bakelite, brass, or the like, is tightly telescoped over each switch at the air gap to 20 hold the switch in its proper position with respect to the magnetic circuit and to keep the pole sleeves 23 and 2I in place.

Of course it will be understood that the parts comprising the magnetic circuit, i. e., the core, 35 the pole pieces and the pole sleeves, are all oi suitable magnetic material, such as high quality Swedish iron. y

A tube 24 is telescoped over each switch with its associatedpole sleeves, and it extends from 30 pole piece to pole piece. These tubes protect the switches from damage, together with a cover plate 25 held in place by screws 26, and a bottom terminal box 21 consisting of a.block 28 of insulating material, and a bottom closure 29, the two being 35 secured to the iron circuit by screws 30. The switches, therefore, when in their assembled position, are completely enclosed and are not subject to tampering by unauthorized persons.

For the purpose of illustration, the switches A 40 and B have been shown as slow make, quick break switches (the time interval for closing the circuit through switch A being somewhat longer than that required for closing the circuit through switch B), and switch C has been shown as a 4 fast acting switch in both making and closing the electrical circuit. All three switches are of the type which include a switch envelope 3| through the base of which a pair of electrodes are sealed, one being constantly in contact with 50 a mercury ll 32 within the switch, and the other being intermittently placed in contact with the mercury (and hence the other electrode) by the action of a displacer 33 which includes a, glass thimble 34 open at its top, as indicated at 35, 55

and an iron sleeve 36 which acts as an armature of the switch. Springs 31 and 3B cushion'the armature in its movement within the switch envelope, and it will be understood that when the coil I0 is energized, the armature is drawn downwardly, causing mercury to be displaced for closing the electrical circuit through the electrodcs, and conversely when the coil ill is deenergized, the armature is restored to its normally raised position for opening the circuit through the electrodes.

Switches A and B diier from switch C in that a time delay element 39 is inserted in the opening 35 at the top of the thimblel 34, ,the element preferably being a porous plug of suitable material such as Alundum (Grade RA 84, RA 360 or RA 98) a product of the Norton Company, Worcester, Massachusetts, or similar material.

The plug is fused into place so that gas entrapped within the thimble during the downward movement of the dlsplacer slowly escapes through the timedelay element, which has the effect of retarding the movement of mercury toward the bared end of the central electrode. This action is shown in Fig. 3 where the coil has just been energized, causing the displacer to move downwardly and trap gas within the thimble to force the mercury away from the central electrode. As the gas pressure on the inside and outside of the thimble slowly equalizes, the mercury level gradually rises until the mercury level within the thimble finally reaches the bared end of the central electrode.

It will be observed that the central electrode of the switch B is somewhat shorter than the corresponding electrode of the switch A so that if the porosity of the plugs 39 in both switches is the same, the circuit through the electrodes of the switch B will be closed prior to the closing of the circuit through the switch A.

When the coil lll is de-energized, all the displacers rise to the position in which they are shown in Fig. 2, switches A and B, however, momentarily carrying up within their armatures a quantity of mercury which tends to keep the circuits through these switches closed, but which is prevented from having this effect by reason of an' aperture 40 provided in the side of the displacer, this aperture allowing gas to enter the displacer as soon as the outside mercury level has dropped below it, and as this takes place almost simultaneously with the de-energization of the coil I0, the result is that switches A and B as well as switch C, effect a quick break of their respective circuits upon de-energization of the coil l0.

There are many circuits in which it is desirable to employ the combination of fast and slow acting switches, and one such example is a motor starting circuit; such as shown in Fig. 5. The motor is indicated at 4| and is energized from a suitable source of electromotive force 42. Starting

resistances

43 and 44 are provided, which are under the control of the mercury switches A, B and C of the control relay, generally indicated at 45. The side electrode of switch C is connected to the central electrode of switch B, and the side electrode of switch B is connected to the central electrode of switch A, so that the resistance 43 parallels the electrodes of switch B, and the resistance 44 parallels the electrodes of switch A. The coil I0 of the relay 45 is energized from a battery 46, or other source, and a switch 41 is provided in series with the coil. When the switch 41 is closed to energize the coil I0, the armatures of all three switches A, B -and C are drawn downwardly,and since switch C is a fast acting switch, current is immediately sent through the motor 4| through resistances 43 and 44 (switches A and B at this instant being open, due to the time delay elements associated with the armatures). As soon as the time delay element of switch B has completed its function so that the electrodes of that switch are bridged with mercury, the resistance 43 is thereby shunted closed again, the starting resistances are automatically thrown into the motor circuit.

It will be understood that in the practice of this invention, it is not essential that the same magnetic circuit be used for operating the several switches, for obviously separate magnetic circuits of equivalent characteristics might be employed. For example, if the magnetic circuits associated with the switches A, B, C and D in Larson Patent 1,967,951 are all identical in every respect, the several switches may have different time delay characteristics. In other words, switches A and B may be fast acting switches, and switches C and D may be slow act ing switches.

In the appended claims, the expression a magnetic flux of given characteristics" is used. This expression is intended to denote the time relationship between the building up of a magnetic iiux and the operation of the switch armatures. In other words, a magnetic flux of given characteristics is a flux which will cause the amature of any switch associated with it to move at a given instant after a predetermined magnetomotive force has been set up.

I claim:

1. In a relay, means for producing a magnetic flux of given characteristics, a pair of switches associated with the means and operated thereby, one of the switches comprising a switch envelope containing a quantity of mercury adapted under certain conditions to provide an electrical path between spaced electrodes in the envelope, means controlled by the flux producing means for manipulating the mercury to eiect a change in the electrical circuit through the electrodes, a time delay element in the envelope adapted to provide a time interval between the actuating of the mercury manipulating means and the changing of the condition of the circuit through the electrodes, the other switch also being actuated by the flux producing means and having a time characteristic diiierent from the rst mentioned switch.

2. In a relay, means for producing a magnetic flux of given characteristics, a pair of switches associated with the means and operated thereby, one of the switches comprising a switch envelope containing a quantity of mercury adapted under certain conditions to provide an electrical path between spaced electrodes in the envelope, means controlled bythe ux producing means for manipulating the mercury to effect a change in the electrical circuit through the electrodes, a time delay element in the envelope adapted to provide a time interval between the actuating of the mercury manipulating means and the changing of the condition of the circuit through the electrodes, the other switch also being actuated by the flux producing means and including a time delay element capable of eiecting a time delay in the condition of the circuit through said other switch which is different from'the time delay effect in the iirst mentioned switch.

3. In a relay, a magnetic circuit including pole pieces, a core connecting them, and a coil for energizing the circuit, a pair of switches associated with the magnetic circuit and operated thereby, one of the switches comprising a, switch envelope containing a quantity of mercury adapted under certain conditions to provide an electrical path between spaced electrodes in the envelope, means responsive to" the magnetic circuit for manipulating the mercury to effect a change in the electrical circuit through the electrodes, a time delay element in the envelope adapted to provide a time interval between the actuating of the mercury manipulating means and the changing of the condition of the circuit through the electrodes, the other switch also being actuated by the magnetic circuit and having a time characteristic different from the first mentioned switch.

4. In a relay, a coil, an iron core through the coil, top and. bottom pole pieces projecting laterally from the ends of the core, and a plurality of switches operatively associated with the pole pieces for response to the coil, one of said l switches including a time delay element and another being immediately responsive to the coil.

5. In a relay, a coil, an iron core through the coil, top and bottom pole pieces projecting laterally from the ends of the core, and a plurality of switches operatively associated with the pole pieces for response to the coil, one of said switches including a time delay element and another having a time delay element of diiIerent characteristics than the time delay element of the rst named switch.

6. In a relay, a coil', an iron core through the coil, top and bottom pole pieces attached to the ends of the core, said pole pieces being segmental in form and having alined apertures, a mercury switch including a vertically movable armature mounted in the apertures, and pole sleeves associated with the pole pieces forfixing the position of the air gap.

7. In a relay, a coil, an iron core through the coil, top and bottom pole pieces attached to the ends of the core, said pole pieces being segmental in form and having a plurality of alined apertures and a plurality of mercury switches mounted in the apertures and including vertically movable displacers shiftable in response to the coil, one of said switches being slow acting and another being fast acting.

8. In a relay, a coil, an iron core through the coil, top and bottom pole pieces attached to the ends of the core, said pole pieces being segmental in form and having a plurality of alined apertures and a plurality of mercury switches mounted in the aperture and including vertically movable displacers shiftable in response tol the coil, pole sleeves associated with `each switch for fixing the position of the air gap, a tube mounted over each switch and its respective pole sleeve and extending from pole piece to pole piece, and means for closing the top and bottom of the apertures so as to completely enclose the switches.

9. In a relay of the class described, means for producing a magnetic flux of given characteristics, and a plurality of switches mounted in operative relation to said means, one of said switches being fast acting and another being slow acting, the latter comprising a stationary switch envelope, spaced electrodes in the envelope, a mercury fill adapted to be manipulated to lmake or break an electrical circuit through the electrodes, and a time delay element adapted to restrain the movement of mercury toward circuit opening position.

10. In a relay of the class described, means for producing a magnetic ux of given characteristics, and a plurality of switches mounted in operative relation to the said means, one of said switches being fast acting and another being slow acting, the latter comprising a stationary switch envelope, spaced electrodes in the envelope, a mercury fill adapted to be manipulated to make or break an electrical circuit through the electrodes, and time delay element adapted to restrain the movement of mercury toward circuit closing position.

11. In a relay of the class described, means for producing a magnetic flux of given characteristics, and a plurality of switches mounted in operative relation to said means, one of said switches being fast acting and another being slow acting, the latter comprising a stationary switch envelope, spaced electrodes in the envelope, a mercury ll adapted to be manipulated to make or break an electrical circuit through the electrodes, a displacer responsive to the ux producing means for shifting the mercury level, and a time delay element adapted to restrain the movement of mercury toward circuit opening position.

12. In a relay of the class described, means for producing a magnetic ux of given characteristics, switch means mounted in operative relation to said flux, said switch means including a quantity of mercury, a pair of electrodes, flux responsive means shifting the mercury to change the condition of the electrical circuits associated with the electrodes, and a time delay element adapted to restrain the movement of mercury in the vicinity of one of the electrodes whereby a time interval takes place between the operation of the flux responsive means and the changing of the electrical circuit associated with said one electrode, the other electrode being immediately responsive to the action of said flux responsive means.

13. In a relay of the class described, means for producing a magnetic flux of given characteristics, switch means mounted in operative relation to said flux, said switch means including `a quantity of mercury, a pair of electrodes, flux responsive means shifting the mercury to change the condition of the electrical circuits associated with the electrodes, and a time delay element adapted to restrain the movement of mercury in the vicinity of one of the electrodes whereby a time interval takes place between the operation of the flux responsive means and the changing of the electrical circuit associated with said one electrode, said flux responsive means effecting a change in the electrical circuit associated with said other electrode, other than simultaneously with the change eiiected with respect to said iirst electrode.

14.'In a relay, means for producing amagnetic ux of given characteristics, a plurality of pairs of contacts associated with and responsive to said means. at least one of said pairs including a time delay element adapted to introduce a specified time interval before aiecting the circuit which said pair of contacts control, another of said pairs of contacts being alienated to aect the circuit which the latter pair control at a time interval, if any, which is substantially different than that eiected by said rst pair of contacts.

CARL H. LARsoN.