US2699478A - Electric relay - Google Patents

Description

1, 1955 H. R. WARNKE ET AL 8 ELECTRIC RELAY Filed March 16, 1951 4 Sheets-Sheet 1 a I v' .75"? 4a. W 6

Jan. 11, 1955 H. R. WARNKE ET AL 2,699,478

ELECTRIC RELAY Filed March 16, 1951 4 Sheets-Sheet 2 Jan. 11, 1955 H. R. WARNKE ET AL 2,699,478

ELECTRIC RELAY Filed March 16, 1951 4 Sheets-Sheet 3 M if /2 M 7/5 25 Jan. 11, 1955 H. R. WARNKE ET AL 2,699,478

ELECTRIC RELAY Filed March 16, 1951 4 Sheets-Sheet 4 United States Patent ELECTRIC RELAY Herbert R. Warnke, Orange, and Leon G. Barry, Whippany, N. J., assignors to United States Instrument Corporation, Summit, N. J., a corporation of New Jersey Application March 16, 1951, Serial No. 215,917

3 Claims. (Cl. 200-93) This invention relates to electric relays such as are used to communicate the change in weak electric current or of a small electrical impulse to another device for operating the device directly or for opening and closing an electric circuit to energize the device, for example to produce a signal. To operate efliciently, a relay must be highly sensitive to the electrical impulses that it receives and relays are, therefore, usually of delicate construction.

However, a delicately constructed relay is not suited for uses in apparatus that operates under conditions of severe shock and vibration, because the relay is easily disturbed and may at times be moved by a slight jar or other motion to a position that causes actuation of the device to which the relay is connected, thereby for example, producing a false signal. In many applications and especially those where conditions of mechanical shock and vibration are encountered, it has been found necessary, therefore, to make the relay of heavy design, as the result of which sensitivity is sacrificed to obtain increased stability.

A general object of the invention is to provide an electric relay that is reliable and highly sensitive to changes in electric conditions and yet is adapted to resist movement due to mechanical shock or vibration. More specifically an object of the invention is the provision of a relay operated switch mechanism that may be moved by a weak electric impulse and then remain stable in its open or closed position unaffected by extraneous influences.

A further object is to provide a relay mechanism that is adapted to respond rapidly to a change in electric conditions and communicate the occurrence of this change to one or several devices and to maintain its effect upon such devices until the mechanism is reset by an operator.

Further objects and various advantages of the invention will become apparent from the following description of a preferred form thereof, reference being made to the accompanying drawing, in which:

Figure l is a plan view of a relay operated switch and signalling mechanism, constructed according to the invention;

Figure 2 is a left end elevation of the mechanism of Figure 1, showing an embodiment in which a preferred form of the relay may be used to operate two contact switches;

Figure 3 is a bottom plan view of the mechanism of Figure 1;

Figure 4 is a right end elevation of the mechanism of Figure 1;

Figure 5 is a longitudinal section taken on line 55 of Figure 3;

Figure 6 is a longitudinal section taken on line 66 of Figure 3;

gigure 7 is a sectional view on line 7-7 of Figure 6; an

Figure 8 is a view similar to Figure 4, but with the signalling plate thereof removed to show the relay in end elevation.

Referring now to the drawing, the relay shown therein comprises an electric motor with two electromagnets rranged side by side and a rotor positioned between the heads or the pole pieces of the electromagnets. For convenience in describing the details of construction of the embodiment shown in the drawing, the ri ht hand end of the mechanism as seen in the view of Fig. 1 will be referred to hereinafter as the front end of the mechanism while the left hand end of the mechanism will be referred to as the rear end thereof.

{The field coils for the motor are designated by the fairly anchor the coils on the cores.

electric material and having a tubular core with a flange on each end thereof. The front ends or pole pieces 13 of the cores 14 and 15 for the coils 10 and 11, respectively, are larger in diameter than are the shanks 16 of cores.

The elements comprising the motor are mounted on a plate 17 having holes 18 therein for accommodating the shanks 16, and the cores are secured to the plate 17 by staking or otherwise. The head portion 13 of the cores extend to the front from the mounting plate 17 while the shanks 16 extend from the rear side of the plate. The field coils 10 and 11 on the spools 12 are then fitted over the shanks of the cores to form the electromagnets of the motor.

In order to prevent the field coils from rotating on their respective cores, the flanges of the spools 12 are formed substantially as a square, and a spacer 19 is inserted between the adjacent coils whereby the straight edges of the flanges of the spools lie against the faces of the spacer to The spacer 19 is supported at its front end on the mounting plate 17 while its rear end is carried on the back plate 20 of a suitable magnetic metal and fixed to the ends of the pole piece shanks by means of the screws 21.

As best shown in Fig. 7 the rotor assembly is positioned between opposed cylindrically concave faces of the pole pieces or head portions of the cores. This assembly comprises a short cylindrical permanent magnet 22 having its poles along the sides of the cylinder, i. e. each of the opposite poles of the magnet is perpendicular to the axis of the cylinder 22. The magnet has an axial bore 23 to accommodate a shaft 24 journaled in the mounting plate 17 at the bearing 25 which in turn is located at the midpoint of a line drawn between the axes of the pole pieces. A casing 26 is provided to cover the pole pieces 13 and the rotor 22 for shielding these parts from injury and from dust that might settle on them and reduce efficiency of the motor. In front of the casing 26 and substantially covering its base portion is a clamping plate 27 having a bearing hole 28 through which the front end of the shaft 24 extends. A hole 29 is also provided in the base of the casing 26 for the shaft 24. Casing 26 and clamping plate 27 are held in place by means of the screws 30 that are tightened into suitably aligned holes in the front ends of the pole pieces.

The shaft 24 is firmly secured in the axial bore of the cylindrical magnet 22 and it rotates with the magnet in bearings 25 and 28. Complete rotation of the rotor or magnet 22 is prevented by means of a stop finger 31 carried by the magnet and a spring stop arm 32 supported on the mounted plate 17. As shown in the drawing, the stop finger 31 may comprise a projection extending from the rim of a small disc 33 which is splined on the shaft 24 in abutting relation to a shoulder 34. When the magnet rotates, the disc 33 with the stop finger 31 will rotate with the magnet until the finger strikes against the spring 32, whereby further rotation of the magnet in the same direction is prevented.

When there is no electric current flowing in the field coils 10 and 11, the pole pieces will exert no magnetic force on the rotor magnet 22; but, since the magnet 22 is a permanent magnet, it will rotate to a position where its magnetic poles are juxtaposed to the pole pieces 13. In other words the permanent magnet rotor will tend to rotate into a position between the pole pieces which provides the magnetic path of lowest reluctance. This will be in line with the pole pieces in either of two positions apart. The rotor is manually set in one of these positions, the stop 31 engaging the spring 32 to prevent the rotor from being set exactly in line with the pole pieces and to bias the rotor in one direction.

For a complete explanation of the action of rotor magnet 22, reference will be made in particular to Fig. 7 of the drawing where the spring 32 biases the rotor to rotation clockwise. Let it be assumed for purposes of this explanation, that the portion of the magnet 22 to the right of stop 31, as seen in Fig. 7, is a north pole Patented Jan. 11, 1955 winding of the coil will cause the head portion of pole a piece 14 to become a north pole when the coil is electrically energized. In a similar way, the head portion of po1e.=piece15,will ,bea south" pole when its .coil'llis energized. The. coils and .11 are connectedin the same. electricalcircuitso :thatthey will become energized snnultanlwusly. Since likemagnetic poles repeleach other, itwill be..seen that when thefield coils-10 and 11 are energized-byra direct current, the magnet 22 will .rotate on. its shaft 24 in thedirection, in which it is biased by the; spring 32 untilits'north pole faces toward the south pole piece and its south pole faces pole piece 14, causingrthe magnet: to stop rotating. Duringthis rotation of themagnet-ZZ, the stop31 will'have been turned to a point.that is about 180 removed from the-position of .the .stop shown .in Fig. 7. The magnet with its-stop willftlienrremain inthis rest position regardless of whether the electromagnets are subsequently de-energized and energized .again, .unless, of course, the polarity of the polespiecesushouldbe reversed, which is not the case in this p'invention'sincethey are arranged to be energized only by directcurrent and. not by alternating current. Whenthe, magnet has reached this rest position and the electromagnets are de-energized, the poles of the rotor magnet will exert apull on the pole pieces. If, therefore, the :mechanism happens to become subiected to a severe shock or vibration, .the rotor will still tend to remain in its rest position. To operate again the rotor must be turnedi manually against the pull of the magnet to its reset. position-where the stop 31 strikes the bias spring 32; The rotor will then tend to remain in its reset-position, unaffected by mechanical shock and vibration, until the coils are again energized.

The stop 31 is made wide enough that when it is 10- cated in. a reset position, i. e. against either of the sides of the bias spring 32, it will maintain the poles of the rotor magnet 22 out of direct alignment with the center of the polepiecesu This. is done in order to eliminate the possibility that the rotor may tend to turn in a direction to keep the stop up against the bias spring. When the stop 31 is positioned to the right of the bias spring 32, as'seen in Fig. 7, the axis of the right hand pole of.

magnet 22 will be positioned below the axis of the magnetic pole of core 14, and the rotor will turn in a clockwise. direction upon energizing of the field coils. When the stop31 is reset to the left of spring 32, and the electric..circuit for the field coils is closed, the rotor will turn counter-clockwise. .Thus, the stop 31 provides a means for predetermining the direction of rotation of the rotor.

It is .clearfrom the above description of the method of operation of the rotor 22 that in order to move the rotor. from a reset position to its rest or inactive position, under normal conditions, the field coils must be energized for only :such time as is suflicient to turn the rotor enoughthat each of its magnetic poles are more than 90 removed from alike pole in the pole pieces. If the rotor were slowly rotated to less than such posi- 'tion'. by .the time thatthe field coils became de-energized,

the rotor would snap back to its reset position due to theyforce ofyits magnetic pull on the pole pieces. It follows, also, that if it be desired to have the rotor rotate from,its reset position in one direction only, then the bias, spring 32 may be positioned close to a pole piece, whereby the poles of the magnet will be only slightly less than90" removed from a pole piece and an electrical charge of very short duration would be necessary to cause the rotor to turn to its rest position.

If .a relatively strong direct current is passed through the coils, the rotor would move from its reset position at a high speed. In such case and where the parts of the relay arecarefully synchronized, the rotor may be madetorotate to its rest position even though the field coils be de-energized where a pole of the magnet is less than 90 removed from like poles of the electromagnets. Thisoccurs because the momentum of the rotor when rotating at-a fast rate carries it to a position where its poles will each be attracted to the next pole piece.

In accordance with the invention the rotor also operates a switch mechanism asection of which is connected in circuit. with the coils 10 and 11 to open the circuit through. said coils. as the rotor passes 90 This is accomplished, by theprovision of a cam associated with thero'torfandia connection betweensaid cam and a switch.

In the illustrated embodiment a pair of contact switch assemblies 35 and .36 I are fastened by" screws-37-to-thebase of mounting plate 17. It will be apparent, how ever, that the relay may operate any number of such switch assemblies, and that it will function properly if connected to only one switch assembly. Each of the assemblies 35 and 36 comprisesiga switching blade 38 adapted to move between the contacts 39 and 40. Switch blade 38 is electrically insulated from the contacts 39 and. 40.by the spacers 41. Contact-39 and switch, blade 38 are connected in the circuit containingthe field .coils if; and 11. When the 1blade38 contacts the element, the circuit to the field coils is closed and the coils may be energized by any" suitable power source. The upper contact 40 is connected with switch blade 38 in the circuit of the device to 'belactuated by the relay.

As best shown in Figures 6 and 8, movement of switch blade 38 from one contact to the other contact is effected through. a cam 44 that is keyed. or "otherwise sfastened on the rotor shaft 24 so as to rota-texwith thezshaft. The cam follower 45, associated with the cam .44, pivots' on the stud 46 journaled -in clamping plate 27.1-A metal yoke 47 is fastened to each of the switch blades38 oft" .the assemblies 35 and 36, beinginsulatedfrom the blades by spacers 47a, and the yoke' carries a roller 48 posi-i tioned in the yoke between the switch blades so that the a roller will be biased by the spring action of the blades". 38 against the contoured edge of cam'follower 45. This contoured edge has a'recessed portion 49 and an extended w portion 50. When the cam follower is swung by'the'; cam 44 to the rightas viewed in Fig. 8,wthe yoke 47 'will be moved downwardly by the extended "-portion50tof. the follower to close the blades 38 against thecontacts-r 39, thereby closing the circuit to the'field coils'offthef relay. When the cam follower is swung to'the left,* the roller 48 will ride-upwardly intothe recessed11portion=49 t' of the cam follower, -thereby breaking the contact of: blades 38 and contacts 39; and then closing the. :switch blades .38 against contacts 40 to close van auxiliary circuit. v Figures 7 and 8 show the relative positions of therotor stop 31 and the'cam 44 when the relay is 'in"a-reset"or" ready position. a In this position; the switch to the lfield coils is closed. i. e. blade 38-is'closed againstcontact 39. When the coils are energized by a suitable electric im- 2 pulse, the rotor 22 and the cam-44 will rotate in -a"clockwise direction moving the cam. follower-towardthe'leftto a position Where the recessed portion :49ofthe cam? follower becomes aligned with the roller :48. :At this point in the rotation of the rotor, the circuit toithe-fieldi. coils will be opened, but the rotor will continue to'rotate due' to the-magnetic pull by itspoles to the pole-pieces" 13 as explained herein above. When the rotorrhas reached its rest positionthe: switch blades 38zwill have closed against the contacts 40 of the auxiliary circuits-i:

The disc 51011 the front end of the'rotorsshaft 24:1 is a means for providing a visual signal that the rotor has operated. This disc has-a colored signal portion 52 on one side thereof. When the relay receives an electric impulse, the shaft 24 *will rotate the disc 51 and, in the preferred embodiment of the invention wherein the": rotor rotates approximately uponactuation of the relay, the signal portion will be rotated to the-dotted" line position "shown in Fig.4; Thus; an attendant 'will know that a signal has been received by the relayuand that the relay has operated, whereupon hewill= reset the relay by turning the disc back to its first position there-u by moving the stop.31-on.-therotor to the biasspring 32, so that the relay can again operate when another electric signal is developed. r r Without further description it is thought that the fea-' tures and advantages of the invention will -.be readily apparent to those skilled in the art, and it will, of'course; be understood that the principle thereof may beem bodied in other arrangements without departingufrom the spirit of'the invention and scope of the-appended claims.

Weclaim: .1. In an electric relayya direct current motor includw ing a permanently magnetized-rotor having 'diametrically opposite poles and electromagnet meansupresenting a pole adjacent to said rotor whereby either of said poles of the rotor will be'attracted toward 'said electromagnet pole. when said electromagnet is deenergized; and stop means preventing complete rotation- 'ofsaid motor but permitting rotation of at'least 1803 and including a stop arm on a fixed support and a stop finger connected to said rotor to abut the stop arm and prevent said rotor from being rotated into a position to bring its poles into exact alignment with said electromagnet pole, whereby said rotor will rotate from a reset or ready position in which said stop finger rests against said stop arm to its inactive position when said electromagnet is energized, said stop arm being resilient and biasing the stop finger to rotation of the permanent magnet in one direction.

2. In a direct current electric relay as defined in claim 1, the addition of a cam mounted on said rotor, a cam follower pivoted adjacent one end on a fixed support and swingable by said cam between two positions, the swinging end of said follower having a follower surface including a projection and a recessed portion, a first switch in circuit with said eleetromagnet means and comprising a spring blade as one arm thereof and a contact element as the other arm of said switch, said spring blade being biased toward said contact element and having connected thereto a part that engages said follower surface whereby said switch is closed when said part is aligned with the recessed portion of said follower surface and opened when aligned with said projection, 21 second switch attached for connection into the circuit of a mechanism to be controlled and including a second contact element as one arm thereof and said spring blade as the other arm of said second switch, said contact elements being on opposite sides of said blade whereby said first switch is opened when said second switch is closed and vice versa.

3. In an electric relay adapted to be driven by direct current, the combination of a mounting plate having spaced openings therein, two spaced apart and substantially parallel electromagnet cores each rigidly mounted in one of said openings with pole pieces extending from one side of said plate and shank portions extending from the other side of said plate, coils of insulated wires on said shank portions for magnetizing said cores, the polarity of said pole pieces being opposite to each other when current is passed through said coils, a clamping plate extending between and rigidly fixed upon the ends of said pole pieces, said mounting plate and clamping plate being substantially parallel to each other, a bearing in each of said plates between said cores, a shaft journaled in said bearings with its axis parallel to the axes of said pole pieces, a permanent magnet mounted on and to rotate with said shaft and between said pole pieces, a cam coaxially mounted on said shaft, a follower for said cam pivoted on said clamping plate and having a cam follower surface, a switch in circuit with said coils, said switch including a spring blade biased toward and having connected thereto a part that engages said cam follower surface of said cam follower, whereby said switch is open when said cam actuates said follower to one position on said pivot in one direction and said switch is closed when said cam rotates said follower to another position in an opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,114,225 Gahusac Oct. 20, 1914 1,733,872 Craseby Oct. 29, 1929 1,763,003 Mead June 10, 1930 1,803,590 Bossard May 5, 1931 1,832,583 Roberts Nov. 17, 1931 2,175,046 Warner Oct. 3, 1939 2,339,021 Lingel Jan. 11, 1944 2,451,343 Kunzle Oct. 12, 1948 2,490,013 Bramley Dec. 6, 1949 2,510,305 Ashworth June 6, 1950

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