US2689279A - Electric switch - Google Patents

Description

Sept. 14, 1954 M. J. NOREGAARD ELECTRIC SWITCH 2 Sheets-Sheet 1 Filed Sept. 21, 1949 Fig.1.

I N V EN TOR. M u ur ice J. Noregaard h a I WEE P 1954 M. J. NOREGAARD 2,689,279

ELECTRIC SWITCH Filed Sept. 21, 1949 2 Sheets-Sheet 2 0 533- ,3 INVENTOR. Ma urz'ce r]. Norggaard BY $7 3 Fig. J6. 142 2 Patented Sept. 14, 1954 UNITED STATES PATENT OFFICE The present invention relates to a switch for making and breaking an electric circuit and more particularly pertains to a magnet actuated switch of the class wherein thecontact points are drawn together and separated upon the activation and deactivation, respectively, of a fioating magnet incorporated in the switch mechanism.

The present application discloses an improved modification of the key operated switch disclosed and claimed in that certain copending application of Hal Cooley for United States Letters Patent, Ser. No. 688,748, filed August 6, 1946, and of the magnet actuated switch disclosed and claimed in that certain copending application of Hal Cooley for United States Letters Patent, Ser. No. 759,049, filed July 5, 1947.

In the first of the above patent applications, namely, Ser. No. 688,748, a switch is described in which one of the contact points is mounted on a swinging arm carrying a magnet. Upon activation of the magnet, the arm swing to bring the contact points into engagement with each other and to close the circuit. Upon deactivation of the magnet, the arm swings back by gravity to separate the contact points and break the circuit.

In the second of the above patent applications, namely, Ser. No. 759,049, a switch i described in which a floating magnet upon activation is drawn against a pair of contact points completing the circuit through the body of the magnet. Upon deactivation, the magnet falls back to its original position, thus breaking the circuit.

In the present application, a switch is described in which one of the contact points is mounted on a resilient arm, which preferably is of conducting material, and which normally holds the contact point on the arm separated from the other contact point of the switch. The resilient arm carries a magnet, and when this is activated, the contact point on the resilient arm is drawn against the other contact point of the switch thereby closing the circuit. Then when the magnet is deactivated, the resilient member returns the contact to its original position spaced apart from the other contact of the pair, thus closing the circuit.

The presently described switch construction has several important advantages. In the first place, the action of the switch is positive, the switch closing and opening with dependable regularity upon activation and deactivation of the magnet. In the second place, the operation of the switch is independent of its position since operates equally well whether disposed horizontally, vertically, or on a bias. Thirdly, the switch i of simple, rugged construction which lends itself to a variety of applications.

The application for which the switch of the present invention, as well as the switches described in the aforementioned patent applications, is intended primarily is the operation of electromagnetic door latch apparatus. In this use, the switch preferably comprises a plurality of pairs of contact points in series circuit relationship with each other and with a source of electrical energy, one contact member of each pair being mounted on a resilient member carrying a magnet. When the apparatus is at rest, some of the contact points are closed and others are open.

To operate the switch, a key having a pattern of magnetic elements corresponding to the pattern of the magnets in the normally open con-- tact units of the switch is employed. When the key is placed with all of the magnetic elements within the fields of force of these magnets, the latter are activated and close the contact units of which they are components against the tension of the resilient mountings. This closes the circuit and opens the latch. Upon removal of the key, the resilient mountings return the magnets to their original positions, separating the contact points, breaking the circuit, and closing the latch.

It will be apparent that, in the above multiple unit, the current passes not only through the contacts which are closed by the magnetic action, but also through the contacts which normally are in a closed position. The latter, also, are provided with magnets and, in the event that it is attempted to operate the switch by use of a solid piece of metal such as a knife blade, or a key having an improper pattern of magnetic elements, they will be opened, thus making it impossible to complete the circuit even though the normally open contacts should be closed by means of the instrument used. This makes the switch substantially pick proof.

When the switch of the present invention is applied to the operation of an electromagnetic door latch, the system lends itself admirably for attachment to club room doors. The key comprising in this case the club membership card in which is concealed the pattern of magnetic elements required for operation of the switch. A problem attending this use, however, is that arising from the fact that many clubs issue memberships on a monthly, quarterly, or semi annual basis. In such a case, it obviously would be desirable to issue membership cards for terms determined by a simple adjustment made on the switch, itself. This adjustment may be made at monthly, quarterly, or semi-annual intervals as desired, thereby rendering inefiective the cards which were issued for such terms only, while not inactivating those cards which are issued for a longer term.

In the switch construction of the present invention, this problem is met by providing a plurality of contact units as described above, but providing also adjustable means for holding one or more of the contact units in closed position at the beginning of the membership period. Those membership cards which are to be efiective for a short term only are not provided with a magnetic element which will operate this unit. On the other hand, those which are to be effective for a longer term are provided with such a magnetic element. Then at the end of the term, the adusting means is manipulated to open the closed contact unit. This automatically ren ineffective the cards for the shorter term, since they have no appropriately placed magnetic element, but does not affect the cards for the longer term which do have such an element.

The presently described switch and its. manner of operation and use will now be described With particular reference to the drawings wherein:

Figure l is a plan view of the switch in one of its embodiments with the housing partly broken away better to show the internal construction;

Figure 2 is a fragmentary sectional view along the line 2--2 of Figure 1;

Figure 3 is a fragmentary sectional view taken along the line 3-3 of Figure 1;

Figure 4 is a fragmentary sectional view taken along the line 4-4 of Figure 1;

Figure 5 is a detail plan view of an alternate construction of one of the contact units of the switch of the present invention;

Figure 6 is a detail view in elevation of the contact unit of Figure 5;

Figure 'l is. a detail view in elevation of still another construction of one of the contact units of the switch of the present invention;

Figures 8-,. 9 and 10 are schematic views in elevation of preferred manners of positioning the magnets in the various contact units of the switch of the present invention so that best operation and closest spacing of the unit may be had;

Figure ll is a schematic view of a circuit including an electromagnetic lock and the switch of Figure 1;

Figures 12, 13, 14 and 15 are plan views of keys which may be used to operate the presently described switch when there are provided adjustable means for cutting in supplementary contact units into the switch circuit from time to time in the manner described above; and

Figure 16 is a plan view of an alternate key construction which may be used in place of the constructions of Figures 12 to 51 inclusive, where it is desired to add additional contact elements periodically.

As will be seen particularly from Figures 1 to 4, inclusive, the presently described switch in one of its embodiments is contained in a housing or casing of suitable construction comprising the back plate I8, the face plates l9 and 20, the core 2 I, and the spacing element 22. These members may be made of plastic or other suitable material and may be fastened together by any suitable means, preferably by means of the bolts 23 so that the mechanism of the lock is easily accessible for inspection and adjustment.

The core member 2| serves advantageously as a mounting for various members of the switch circuit and is perforated transversely in a pattern corresponding to the pattern of magnets it. is. desired to employ.

The housing is provided with a slit. 24 which is adapted to receive the key which operates the switch. The slit may be formed as a cavity within the face plate 20, although it is preferred to form it by providing the spacing members 25 interposed between the face plate and the body of the switch.

Also interposed between the face plate 20 and the body of the switch is the sheet 26 which may be of copper or other suitable material and which is at least coextensive with the ceiling of the slit. This plate serves as a shield to prevent entry of the magnets into the slit and consequent defacing of the key or interference with its use. In this manner there is provided for the introduction of the key a chamber which communicates with the exterior on one side, but which is bounded by the spacing member on three sides, by the face plate 2.0 at the bottom, and by the plate 23 at the top. The walls of this chamber form a guide which enables placing a key having dimensions only slightly less than those of the chamber within the chamber in such a manner that magnetic elements in the key are within the fields of force of the magnets within the body of the switch.

The key 28 employed to operate the switch of Figures 1 to 4, inclusive, may comprise a membership card made of fibrous layers in the interior of which are placed a plurality of magnetic elements 23 which may be pieces of shim steel or the like. Alternatively, the magnetic elements may comprise patches of iron filings or other suitable magnetic material applied by means of an adhesive or otherwise affixed to the card. In either case, the pattern of the magnetic elements corresponds with the pattern of the normally open contact units within the look.

In the switch illustrated in Figures 1 to 4, there are three such normally open contact units arranged in a characteristic pattern and connected in series with each other and with a source of electrical current. The latter enters the switch through an opening in the back plate I8 via the line 30, which is held firmly in place by suitable means such as the clamp 3|. One side of the line is connected to the conductor 32 which is aflixed to the core portion 2| and held in contact with a second conductor 33 by means of the screw 34. The conductor 33 forms one element of the contact unit 35 (Figure 2). It preferably comprises a strip of spring bronze or other resilient conducting material doubly perforated and formed with a reverse bend which brings the perforations in alignment with each other so that they may be penetrated by the screw 34 entering the core 2|.

The conductor 33 has on its terminal portion a contact point 36 which is adjacent but spaced apart from the conducting finger 31 on the screw 38, which likewise is attached to the core 2 Also attached to the conductor 33 is the magnet 39. This preferably is an elongated permanent magnet of the Alnico type extending outwardly from the conductor 33 substantially through an opening 40 in the core 2|. The magnet 39 may be attached to the conductor 33 in any suitable manner as by soldering it to the conductor, tying it on, or gluing it on with a suitable adhesive. However, for the purposes of the present invention, it has been found preferable to attach it securely by forming the conductor 33 with a pair of lateral, integral extensions 4| which may be bent parallel to. each other to form a channel adapted to receive the magnet. An end of the latter is coated with adhesive and inserted in the channel until the adhesive coated end is in contact with the conductor 33. The extensions then are clamped onto the magnet by binding them with a suitable material such as the windings 42.

It will be apparent, especially from Figure 2, that, when a magnetic element 29 contained in a key 28 is inserted in the slit 24 and stationed immediately adjacent the magnet 39,, the latter will be attracted toward the magnetic element, thus bending the conductor 33 until the contact point 36 touches the finger 31, completing the circuit through this contact unit. However,

I when the key is withdrawn from the slit and the magnetic element removed from the field of force of the magnet, the resilience of the conductor 33 will cause it to resume its original position, thus separating the contact point 36 from the finger 37 and breaking the circuit in the contact unit.

The proper spacing of the contact point 36 from the finger 31 obviously is of considerable importance in determining the proper operation of the switch. If the space which separates these two members is too great, proper contact may not be made upon activation of the magnet 33. On the other hand,if the space is too small, contact may be made upon an inadvertent jarring or shaking of the switch without use of the key.

In the embodiment illustrated in Figures 1 to 4, the proper spacing of the contact point and finger is obtained by adjusting the screw 34 which penetrates the two perforations in the resilient conductor 33. Drawing up on this screw will bring the contact point 36 in closer proximity to the finger 31 while releasing the screw will increase the distance between these two members.

An alternate means for controlling the spacing between the contact points is illustrated in Figures 5 and 6. In this embodiment, the conductor 45, corresponding to the conductor 33 of Figure 2, is mounted on and attached to a source of electrical energy through the post 46. The conductor 45 bears the contact point 41 at its outer terminal portion and the magnet 48 at its intermediate portion. The magnet 43 is attached to the conductor in any suitable'manner and is adapted to be contained in a perforation through the core 2| in the manner explained above. Cooperating with the conductor 45 and contact point 41 is the finger 49 normally spaced apart from the contact point and communicating through the post 50 with the rest of the electrical circuit.

The conductor 45 preferably is formed from a resilient strip of conducting material so that, being anchored at its rear portion to the post 43, it may spring back and forth in order alternately to draw together the contact point 41 and the finger 49 and then to separate them. Thus when a magnetic element is brought within the field of force of the magnet 48, the resilient conductor is drawn down until contact is established and the circuit closed. However, upon removal of the magnetic element, the resilience of the conductor causes it to spring back and break the circuit.

The extent to which the resilient conductor 45 springs back during the foregoing sequence is determined by the stop member 5| attached substantially at right angles to the post 52 which is embedded in and insulated from the electrical circuit by the core 2|. The stop 5| preferably is formed from a deformable material such as a nonresilient metal strip so that it may be bent in any desired degree to effect the proper spacing of the contact point 41 and the finger 49. In this manner, the spacing may be adjusted to a value at which the switch operates properly upon the introduction of the proper key but at which it will not inadvertently be operated by a sudden shock.

A preferred means of controlling the spacing between the contact points is illustrated in Figure '7. In this embodiment a magnet extending through a perforation in the core 2| is attached to the resilient arm 53. One end of the arm bears the contact point 54, normally spaced apart from the contact 55 which is connected to the rest of the circuit in a manner analogous to that illustrated in the case of contact 31 in Figure 2. ihe other end of the arm 53 is attached to the core 2i through the screws 53 and the interposed block 51. The latter has a projection on its bearing surface, preferably the lower surface in contact with the core, one of the screws 56 being located on each side of the projection. Hence adjustment of the screws is reflected in a rocking motion of the block 51 and a corresponding oscillation in the arm 53. This makes possible close adjustment of the spacing between the contact points 54 and 55. Then when the spacing has been adjusted as desired, the screws 53 may be tightened to lock the arm securely in the desired position.

A thumb screw 58 also is provided in connection with the contact unit 35. It penetrates the face plate i9, and extends through the cavity in which the lock mechanism is contained until it comes in contact with the resilient conductor 33. By adjustment of the thumb screw, it is possible to depress the conductor until the contact point 36 touches the finger 31, thus transforming the contact unit from a normally open unit to a normally closed unit. This adjustment may be reversed by unscrewing the thumb screw 58, whereupon the conductor 33 will be released and will resume its normal position maintaining the contact point 36 separated from the finger 31 by a space determined by the setting of the screw 34. In this manner there is provided an external means for controlling the character of the contact unit, the purpose of this being developed more fully hereinafter.

As an alternate for the thumb screw 53, there may be provided a switch 58a in a circuit bypassing the contact unit 35 (Fig. 11). this switch will have the same eifect as operation of the thumb screw in transforming the contact unit 35 from a normally open unit to a normally closed unit.

The remaining normally open contact units in the switch may be substantially identical in their construction to the contact unit 35 described above. Thus the contact unit 53 which is in series with the contact unit 35 comprises a resilient conductor 53 attached to and adjustable by the screw SI. The conductor carries the magnet 62 and contact point 63 which normally is apart from the contact finger 64. Just as the magnet 39 projects through the opening 43 in the core 2|, so the magnet 62 of unit 59 projects through an opening in the core, thus forming another element of the magnet pattern in the core.

The third normally open contact unit 35 is in series with the contact units 35 and 55 previously described. It comprises the resilient con- Closing acsasvo 7. ducting arm 66 adjustable by means of the. screw 61 which also attaches it to the core and. connects it with the rest of the circuit. On the conductor 6.6 is the magnet 68 and th contact point 69 which normally is separated from the conducting finger In, which, however, it contacts upon activation of the magnet 68 and bending of the resilient conductor 66. The magnet extends through the perforation H in the core 2|. and thus forms still another element of the magnet pattern in the core.

Also included in the circuit of the switch of the invention are. one: or more normally closed contact units. Such a unit is illustrated in Figures. 1 and 3. Its construction is similar to that of the normally open units with the exception that the contact point on the re.- silient conductor is, held normally in contact with the finger forming the other member of the contact pair. Thus the unit comprises the resilient conductor 16 adjustably attached to the core 2| through the screw 11. A permanent magnet 18 is attached to the resilient conductor as is the contact point 19. As before, the contact point 19 is adapted to touch a contact finger 80, which, in this instance, is stationed at the far side of the contact point 19 with reference to a key placed in the slit 24. The magnet 18 extends through an opening 81 in the core thus forming the final element of the particular magnet pattern illustrated in the drawings.

It will be apparent, particularly from a consideration of Figure 3, that the contacts 19 and 89 normally are held together by the pressure of the resilient conductor 16. However, when a magnetic element is placed in the slit 24 and stationed below the magnet 18, the latter is drawn toward the magnetic element thus de pressing the resilient conductor l6 and separating the contact points and breaking the circuit. Upon removal of the magnet element, however, the resilient conductor "I6 springs back into place, again establishing contact between the contact points and closingthe circuit.

There also may b included in the circuit of the switch of the present invention a mechanically operated contact unit 85, the construction of which is particularly evident from Figures 1 and 4. This is stationed at or toward the rear of the switch and is operated by the key as it is inserted into the slit 24. The contact unit 85 comprises a fixed conductor as connected to the conducting element 8? which, in turn, is connected with the resilient conducting member 66 of the contact unit The fixed conductor 89 has on its end a contact point 88 which normally is spaced apart from a contact point 89 on the conductor 99. The latter conductor is connected directly to one side of the line bringing electric current into the switch.

The conducting element 90- is attached at its rear terminal portion to the core 2| through the screws 9|. It is formed of a resilient conducting material and has at its forward portion a projection 92 which extends substantially at right angles to the body of the element and which projects into the slit 24. This projection serves as a member to be contacted by a key to be introduced into the slit and when this occurs, the resilient conductor 90 is. bent rearwardly until the contact point 89 touches the point 88 thus closing the circuit through this unit.

The mechanical contact. unit 85- serves at least two valuable. functions: when incorporated in a circuit together with the magnetic con.- tact units 35, 59, 65 and 15; In the firstplace,

it makes mandatory the insertion of the key to.

its full depth within the slit 24 before the lock will? operate. When the key is a club: membership. card of the usual dimensions,v this makes.

possible the. incorporation in such. a card" of as many as. two or' three thousand different. combinations of magnetic. elements since substantiallythe entire. surface area of the. card is; available for this purpose. On the other hand, if

it. were not necessary to. introduce. the card to the full extent. of the. slit. 24' the number of combinations would be limited correspondingly.

In the second place, the: mechanical contact.

unit is the. last of the. contact units in. the circuit to close when. a key is. introduced into the slit and the first to open. when the. key is. removed. For this reason, all of the arcing. which inevitably occurs. when any electrical circuit is made and broken. takes place at this unit. In view of its mechanical activation, the unit 85 may be of relatively heavy construction so that it will not burn or corrode during arcing to the point where its operation is impaired. This greatly increases the service life of the switch.

While investigating the various magnet patterns which may be employed in the switch of: my invention, I have discovered that, by the use of a simple: expedient (Figures 8', 9 and 1.0), the

number of patterns. which may be employed magnet 95 and a second magnet 96 are placed.

closely adjacent to each other in the core. 21 and a key 28 having a magnetic. element. is placed in a position calculated to activate the magnet. 55- but not the magnet 95, this magnetic element. will have an efiect. also on the magnet 96 which it is not desired to activate. If the two magnets 95 and 96 are. placed with like poles opposite each. other, for example the north poles: as shown inthe figure, a repelling action occurs between the two like. poles which tends to prevent the magnet 96- from being. drawn to a position where it would be somewhat closer to the magnetic element 29 in the key. This. effeet is augmented, of course, by the fact that. the opposite pole, i. e. the north pole of the magnet 96 exerts anattractive force on the south pole of the magnet 95. This attractive force, reinforces. the pull of the magnetic: element 29 on. the. magnet 95. so that the latter moves readily toward the magnetic element to close the switch as shown in Figure 9. As a. result, the two magnets may be placed quite. close together in the core of the switch without. the magnet 96 being afiected by the magnetic element intended toactivate the magnet 95'.

If, on the. other hand, the magnets are arranged with unlike poles opposite each other. as indicated in Figure 1.0, the. reverse situation obtains. In this case, the north pole of the magnet ti exerts an attractive force uponthe south pole of the magnet 98. If, in addition, the two magnets are placed close enough together so that the magnetic. element 29 in the key 28' comes even slightl within the field of force of the magnet 58, the combined efiect of. these two factors may be suflicient to more the magnet 98 and close the magnetic contact of which it is a member. Therefore, by placing adjacent magnets with like poles opposite each other, the magnets may be placed relatively close to each other in the core of the switch and the number of magnetic patterns which may be used with a switch and key of given dimensions very greatly increased.

As has been indicated above, the switch of the present invention may be incorporated in any suitable electrical circuit, but it is particularly adaptable for use with a solenoid actuated lock mechanism used for locking and unlocking a door. The circuit for such a mechanism is set out in Figure 11 of the drawings. The circuit includes a source of electrical energy such as the batteries Iiit, the normally open contact units 35, 59, 65, the normally closed contact unit I5, the mechanical contact unit 85, and the solenoid IOI operating the latch. m2 all in series together. Then when a key is introduced into the switch having a pattern of magnetic elements corresponding to the pattern of the magnets in the normally open contact units 35, 59 and 65, the key being inserted sufiiciently to close the mechanical unit 85, the circuit will be closed and the solenoid energized to withdraw the latch from the door which then may be opened. Upon removal of the key, the normally open contact units will be returned to their open position, the solenoid de-energized, and the latch returned to locking position by a conventional spring mechanism not However, if the pattern of magnetic elements in the key is not such as to correspond to the pattern of the magnets in all of the normally open contact units, or if magnetic material is inserted within the sphere of influence of the magnet of the normally closed contact unit, the circuit will not be closed and the lock will not operate.

As has been indicated above, the switch of the present invention may be operated by a key comprising a card having concealed therein or attached thereto a pattern of magnetic elements corresponding to the pattern of the magnets in the switch. The magnetic elements preferably comprise small pieces of thin, flexible shim steel or similar magnetic material having an area approximatel equal to or slightly greater than the area of the magnet ends. When pieces of this stock are interposed between two or more plies of fibrous material which then are glued together to form a card, the resulting card is indistinguishable by ordinary inspection methods from a card not containing the magnetic pieces. Hence it may be flexed, pressed between the fingers, or otherwise inspected without being able to trace the pattern of the pieces.

Where the card is a club membership card, it may be furnished to the member in any one of several different styles, each style being adapted to operate the lock on the club rooms for a specified term. Thus as is illustrated in Figures 12 to 15, inclusive, four cards may be supplied and issued to the members for various membership terms, which may be on a quarterly basis. The first card I65 (Figure 12), will operate the lock during the first quarter only. It contains em.- bedded within it the two basic magnetic elements Hit and Isl. These suffice to operate a lock having two normally open contact units of corresponding pattern, for example, the contact units 59 and of the switch of Figure 1.

The card Ila of Figure 13 is designed to operate the lock during the second quarter as well as the first quarter. In addition to having the two basic magnetic elements Ij I and I I corillustrated.

responding to magnetic elements its and it! of the card of Figure 12, it contains a third magnetic element H3. The latter is designed to operate a contact unit such as the unit 35 of Figure 1 which is held closed during the first quarter by means of a thumb screw. At the expiration of the third quarter, the thumb screw is released thereby opening the contact unit. This automatically Voids the card I05 which has been issued for the first quarter only and which contains no magnetic element corresponding to the element I I3 of card H0. The latter card thus automatically becomes the currently valid card for operating the look.

In a similar manner a third quarter card H5 (Figure 14) may be provided Which contains in addition to the two basic magnetic elements I I6 and I I! the two elements H8 and I I9. This card may be used when a second contact unit (not illustrated) which has been held closed by a thumb screw or other suitable means during the first two quarters is opened.

The card I29 of Figure 15 is designed for use during the fourth quarter. This contains in addition to the two basic magnetic elements IZI and I22, and the two elements which activate the lock during the second and third quarters, i. e. elements I23 and I24, respectively, still another element I25 designed to operate a contact unit (not illustrated) which is held closed during the first three quarters but which is opened at the beginning of the fourth quarter, thus voiding automatically all of the cards for the previous quarters. This affords a graceful means for the club management to call to the attention of its members the fact that their dues for a given period have not been paid.

The above system for providing cards valid for varying terms may be carried out also by providing a card I39 which corresponds to card IZb in that it incorporates in the first instance all of the magnetic elements which are required to operate the locks throughout the year. Thus it contains the two basic magnetic elements ISI and I32 as well as the elements I33, I3 and I35 required to operate the latch during the second, third and fourth quarters, respectively. However, the area directly above the latter three magnetic elements is defined by a suitable marking such as a circle so that by means or" a punch or other suitable instrument, the magnetic element and that portion of the card above and below it may readily be removed. Then if it is desiredto issue the card for the first quarter only, all three of the magnetic elements I33, I35 and I35 may be punched out leaving only the two basic elements I3I and I32 which will operate the lock for the first quarter only. If it is desired to issue the card for the first two quarters, the magnetic elements I34 and I35 are removed. Similarly, if the card is to be valid during the first three quarters, the magnetic element I35 only is punched out while if the card is to be good for the entire year, it is issued with all of the five magnetic elements contained therein.

Although, when punching out magnetic elements in the manner indicated, the area to be punched may be defined by markings on the face of the card, it may, in many instances, be preferable to provide a first card containing the magnetic elements and having the appropriate marl:- ings for punching, a second card bearing the usual membership data and signatures, and a third card serving as a backing sheet. The card GQntaining the magnetic elements then may be punched as desired and placed between the two other cards, suitable adhesive being applied to form an integrated card in which the manner of punch-ing is not readily apparent.

Thus by the present invention, ,1 have provided a versatile switch which may be used to operate a variety of electrical circuits. My switch is characterized by being operable in any position and not subject to inadvertent operation by sudden shock. It is substantially pickproof in view of the lar e number of combinations of magnetic elements (142,500 ,for elements used in 30 positions) which may be employed. Furthermore, it may be made operable by a plurality of keys, each of which is valid during ,a given time period without reconstruction or replacement of the lock mechanism. On the contrary, by a simple adiustment to open one or more of the contact units, the lock may be made operable with a given key and inoperable with the keys which theretofore had been effective.

Having now described my invention in preferred embodiments, I claim:

1. An electric switch comprising a base, a block having a projection thereon bearing upon the base, a resilient conductor attached to the block and having a contact point thereon, a second electric conductor having a contact point thereon, the contact points on the two cohductors'being opposite and spaced apart from each other, a magnetic member attached to the first resilient conductor and extending freely through the base and adapted upon activation from the side of the base opposite the block to draw the contact point on the resilient conductor against the contact point on the second conductor against the tension of the resilient conductor, thereby closing the switch, the resilient conductor returning the contact point thereon to its original position apart from the contact point on the second conductor upon deactivation of the magnetic member, thereby opening the switch, and a pair of screws extending through the block and into the base, one screw being stationed on each side of the projection on the block, whereby to permit, upon adjustment of the screws, the pivoting of the block about the projection thereon and the corresponding adjustment of the spacing between the contact points.

2. An electric switch mechanism comprising in combination a key having a substantial surface area and carrying a plurality of magnetic elements distributed in a characteristic pattern over said area, and a. switch comprising ,a plurality of pairs of electric contacts in series with each other, a plurality of resilient members each one of which is attached .to one of the contacts of said pairs of contacts, and a plurality of magnets mounted one on each of said resilient members and arranged in a pattern corresponding to the pattern of magnetic elements in the key, the magnets being adapted to close the contact pairs upon the approach of the key when the magnetic elements thereon are positioned within the fields of force of the magnet, thereby closing the switch, the resilient members being adapted upon the withdrawal of the key to open the contact pairs, thereby opening the switch, and adjustable means for holding one of the contact pairs closed when it is desired to render it inoperative as a circuit breaking element of the switch, and for separating said one of the contact pairs when it is de- .sired to include it as a circuit breaking element of the switch.

3. An electric switch mechanism comprising in combination a key having a substantial surface area and carrying a plurality of magnetic elements distributed in a characteristic pattern over said area; and a switch comprising a plurality of pairs of electric contacts in series circuit relationship with each other, a plurality of members arranged in a pattern cor-respondmg to the pattern of magnetic elements in the key, mounting means for mounting each of said magnet members movably adjacent a corresponding one of said pairs of electric contacts for operating said pai-r when a magnetic element of the key is positioned within the field of force of the magnet member, and adjusting means for adjusting one of the electric contact pairs between open and closed positions when it is desired to change the circuit condition of said electric contact pair.

4. An electric switch mechanism comprising in combination a key having a substantial surface area and carrying a plurality of magnetic elemerits distributed a characteristic pattern over said area, at least one of said magnetic elements being removable to alter said pattern; and switch comprising a plurality of pairs of electric contacts in series circuit relationship with each other, a plurality of magnet members arranged in a pattern corresponding to the pattern of netic elements in the "key, mounting for mounting each of said magnet members movably adjacent .a corresponding one of said pairs of electric contacts for operating said pair when a magnetic element of the key is positioned within the field of force of the magnet member, and adjusting means for adjusting one of the electric contact pairs between open and closed positions when it is desired to change the circuit condition of said electric contact pair.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 283,748 Bernstein Aug. 188-3 586,888 Williams July 20, 708,539 Fell Sept. 9, 716,653 Alexander Dec. 23, 1002 909,594 Heinze, Jr. Jan. 12, 1909 1,048,670 Fessenden Dec. 31, 1912 1,105,465 Stone July 28, 1914 1,239,790 Hendrickson Sept. 11, 1917 1,622,042 Miles et .al. Mar. 22, 1-927 1,693,491 Ogden Nov. 27, 1928 1,731,188 Avery Oct. 8, 1929 1,765,479 Benson 1 June 24, 1230 2,014,286 Nelson Sept. 10, 1935 2,050,665 Matthews et al 1. Aug. 11, 1936 2,057,532 Macdonald Oct. 13, 1036 2,121,301 Ractliffe June 21, 1938 2,208,225 Nelsen et a1 July 16, 1940 2,265,203 Six Dec. 9, 1941 2 ,393,428 Stroud Jan. 22, 1946 2,473,664 Taylor June 21, 1949 2,490,906 Hennigar et al M Dec. 1949 2,566,017 Cooley Aug. 28, 1951 2,595,769 Cooley May 6, 1952 2,595,811 Price May 6, 1952 250 5 4 Schilling July 3, 1

FOREIGN PATENTS Number Country Date 444 Great Britain Jan. 7, 1914 119-13 237,269 Switzerland Aug. 16, 1945 308,398 Great Britain Mar. 28, 1929

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