US3494157A - Magnetic lock - Google Patents

Description

Feb. 10, 1970 F. 'r. COKER, JR 3,

MAGNETIC LOCK 7 Filed Aug. 1. 1968 2 Sheets-Sheet 1 .INVENTOR. FREDERICK T. COKER, JI'

ATTORNEY United States Patent 3,494,157 MAGNETIC LOCK Frederick T. Coker, Jr., Boylstou, Mass., assignor to Ilco Corporation, Fitchburg, Mass., a corporation of Massachusetts Filed Aug. 1, 1968, Ser. No. 749,484 Int. Cl. Eb 19/26, 47/00 US. Cl. 70-276 16 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention This invention is in the field of locks, and particularly high security locks. Still more particularly, this invention is in the field of locks employing magnetic elements as the means for releasing a lock from the locked position thereof.

The prior art It has been proposed for many years to provide locks which operate on magnetic principles. Examples of a variety of forms of such locks may be found in the following US. patents: No. 2,966,789 of Jan. 3, 1961 and No. 3,111,834 of Nov. 26, 1963.

Despite the existence of such designs, the proportion of magnetic to mechanical locks has remained very small and magnetic locks have heretofore enjoyed a very limited acceptance. The limited use of locks of this type is considered to be occasioned by a series of factors including high initial cost, low security, problems in forming replacement keys and high cost of such keys, the limited number of available locking combinations, and the tendency, after protracted use, of keys to lose their ability to release the locking mechanism.

In early magnetic lock designs, lock elements were aligned in one or two planes and a skillful manipulator having knowledge of the design of the lock could compromise the lock through the judicious use of magnetic picks.

In more recent designs, greater security was achieved, at the expense of great complexity, by offsetting the locking members at a multiplicity of diverging angles. Such complex devices required for their operation a key having a multiplicity of magnetic members disoriented from each other at angles corresponding to the angles of the magnetic lock operating members. As will be readily apparent, such a key is exceedingly difficult to manufacture and the tools, jigs, dies and knowhow required for their duplication are far beyond the capacity of the ordinary locksmith.

Thus, in the only reasonably secure magnetic lock known to be available on the market, replacement keys must be procured from the factory, with attendant delays and at a considerably higher cost than normal replacement keys.

Heretofore all magnetic locks have required the use of keys containing magnets. A drawback of magnet con- 3,494,157 Patented Feb. 10, 1970 taining keys lies in the fact that the magnetic forces are reduced by a'factor which is proportional to the square of the distance between the spaced magnetic components. Since all magnetic keys must provide clearance between the magnets in the key and the magnets contained in the lock, there is an inherent separation in such units which necessitates the employment of particularly high strength, large sized magnet components. Further, since the magnet materials used in the key device are easily fractured or crumbled, it is necessary to provide a protective layer or shield over the shank of the key to prevent damage to the magnets. Such shield further reduces the magnetic efiiciency of the device by requiring a still greater spacing of the parts and by adding a low permeability material between the magnet units.

SUMMARY OF THE INVENTION A magnetic lock operable by a non-magnetic key and having locking means shiftable between lock plug releasing and lock plug locking positions and incorporating magnetic means within the lock for releasing the locking means, characterized by movable magnetic carriage means shifted by insertion of a proper key to predetermined aligned position with the magnetic lock releasing means. The carriage means may be shiftable axially or transversely or angularly within the lock plug, or may be moved in a combination of such directions.

It is therefore an object of the invention to provide an improved magnetic lock.

It is a further object of the invention to provide an improved lock of the type described which use a conventional, e.g. non-magnetic, key.

A further object of the invention is to provide a device of the class described having high security.

A further object of the invention is to provide a lock having in combination with a magnetic locking system of the type described, a series of conventional locking elements.

To attain these objects and such further objects and such further objects as may appear herein or be hereinafter pointed out, reference is made to the accompanying drawings, forming a part hereof, in which:

FIGURE 1 is a vertical section through a lock device incorporating a magnetic locking component in accordance with the invention;

FIGURE 2 is a view siimlar to FIGURE 1 showing the lock device in the release position thereof;

FIGURE 3 is a section taken on the line 3-3 of FIG- URE 2;

FIGURE 4 is a vertical sectional view of an embodiment of the invention;

FIGURE 5 is a view similar to FIGURE 4 showing the position of the parts in the unlocked condition;

FIGURE 6 is a section taken on the line 6-6 of FIG- URE 5.

Referring now to the drawings, there is shown in FIG- URES l to 3 a lock device incorporating a series of conventional locking pin tumblers in conjunction with an auxiliary magnetic locking element.

In the noted embodiment, a lock housing 10 is pro vided with a cylindrical bore 11, within which bore is rotatably mounted a lock plug 12. The plug 12 has an annular shoulder portion 13 adjacent the outer face of the lock which is enlarged in relation to the main body of the plug, the shoulder abutting an outwardly directed complemental shoulder 14 adjacent the outer end of the housing. The abutting faces of the shoulders 13, 14 prevent inward movement of the plug relative to the housing.

An essentially conventional lock operator cam 15 is affixed within a slot formed adjacent the inner end 16 of the plug, as by a parallel pair of machine screws 17, 17,

the inner ends 18 of which are threadedly connected within complemental tapped apertures formed in the interior of the plug. The machine screws 17 include medial unthreaded shank portions 19 for purposes which will be explained hereinafter.

A plurality of cross bores 20 extend from the housing into the plug 12, in well known manner. The cross bores 20 are filled with the usual follower pins 21 and driver pins 22, there being included, if desired, the usual intermediate pins for mastering. The pins 21, 22 are urged radially inwardly toward the keyway 23 by springs 24, the inner radial ends of which are pressed against the follower pins 21. The outer ends 25 of the springs are biased against a spring retainer slide 26 seated within an undercut, dove-tailed slot formed in the housing.

It will be readily recognized that the operation of the locking pins is, in all respects, conventional, the pins functioning in the usual manner to lock the plug against rotation relative to the housing until the pins are lifted to align the junctions of the driver and follower pins 21, 22 with the shear line 5-5, coinciding with the junctio of the plug and housing.

In accordance with the present invention, additional security is provided by a magnetically activated lock mechanism. The magnetic lock mechanism comprises an additional cross bore 30 formed in the housing 10, which cross bore is disposed in registry with a cross bore 31 formed in the plug in the locked position of the apparatus.

The locking pin 32 is biased downwardly by driver spring 33 so that the lowermost end of the pin 32 extends across the shear line SS and into the cross bore portion 31 of the plug. The cross bore 31 may include a lower, reduced diameter portion 31'. Seated within the cross bore portions 31, 31 is a magnetic locking pin 34, incorporating an enlarged head portion 35 and a reduced foot portion 36.

As will be observed from FIGURE 1, the magnetic pin 34 is pressed radially inwardly by the downward force exerted by the pin 32 under the influence of driver spring 33. The magnetic pin 34 is formed so that the poles lie at the upper and lower faces of the pin, in the illustrated embodiment the lowermost pole being the south pole and the uppermost pole being the north pole.

The magnetic pin is released to the unlocking position thereof by an appropriate axial movement of a slide assembly 37 disposed within a clearance way 38 formed adjacent the inner end of the lock plug. The slide assembly 37, as best seen in FIGURE 3, comprises a wafer member 39 of parti-circular conformation and formed with a pair of laterally spaced- apart apertures 40, 40 through which slidably extend the shank portions 19, 19 of the retainer screws 17.

A pair of wafer springs 41 are sleeved over the shanks 19, the forward edges 42 of the springs being pressed against the rear face of the wafer 39, the rear end 43 of the springs being biased against a rear portion of the lock plug. It will be observed that the springs 41 function to urge the wafer 39 yieldably toward the front or outer end of the lock plug and against a rearwardly facing shoulder 44 formed on the plug. The wafer 39 is provided with an upwardly directed recess 45, within which recess is mounted a lock operator magnet 46. The polarity of the lock operator magnet is adjusted so that the upper pole of said magnet is the same as the polarity of the lower pole of the magnetic pin 34.

The wafer 39 is provided with a clearance slot 47 in alignment with the keyway 23 of the plug, the slot 47 of the wafer being preferably formed with the usual irregular cross section to correspond with the remaining portions of the keyway 23.

The lock is operated by a specially formed key 48, having the usual hitting 49. The bitted portions 49 function to lift the lower pins 22 so as to align the junction of the upper pins and the lower pins with the shear line SS. In addition, the key 48 includes a transverse shoulder 50 adjacent the innermost end of the key, which shoulder is of a height to permit the tip portion 51 of the key to pass through the slot 47.

When the key 48 is inserted, it will carry the wafer 39 a predetermined distance rearwardly. Obviously the amount of inward or rearward movement imparted to the wafer 39 by the key 48 will be a function of the spacing of the shoulder 50 from the main key shoulder 52. In a properly formed key, this spacing will be such as to cause the magnetic insert 46 carried by the wafer to be precisely aligned beneath the magnetic pin 34, to align the like poles (in this instance, the south poles) of the magnets 46 and 34 when the key is fully inserted.

When this relation is achieved, an outward repelling force will be exerted against the magnetic pin 34, lifting the junction of the pins 34 and 32 to the shear line SS. The lock may then be operated by the key since the junctions of all of the pins, i.e. the conventional locking pins 21, 22 and the magnetic control pins 34, 32 will have been disposed at the shear line.

Optionally and preferably, means are provided to assure that the magnetic pin 34 is not elevated upwardly into the cross bore 30. A multiplicity of mechanisms for this purpose may be envisioned, including selective sizing of the bores to prevent such entrance, the use of a cross pin to prevent undue lifting of the magnetic pin, etc.

Preferably also, the spring 33 exerts a relatively light downward force on the pin 32 so that only minimal forces must be overcome by the repelling magnetic components. Desirably, the magnet components of the pin 34 and the magnetic insert 46 are balanced with respect to the force exerted by the spring 33 in such manner that the lifting force applied by the magnets is insufficient to raise the junction of the magnetic controlled pins to the shear line unless a precise alignment of the magnetic elements is achieved. In other words, it is preferable to prevent lifting the magnetic pin junction to the shear line if only partial registry between the magnetic pin and the magnet 46 is achieved, such construction obviously adding to the security of the lock.

While in the embodiment of FIGURES 1 to 3 the magnetic element has been shown at the innermost end of the lock plug, i.e., inwardly of all of the conventional pins, it will be readily appreciated that the magnetic looking component may be disposed centrally of the conventional locking pins or outwardly of such pins.

Similarly, while only a single magnetic locking element has been shown in combination with multiple conventional locking units it will be readily recognized that two or more magnetic locking members may be employed.

Turning now to the embodiment of FIGURES 4 to 6, there is disclosed a device wherein the locking function is provided solely by a series of key actuated magnetic control elements. In this embodiment the housing 60 is formed with the usual central bore 61, within which bore the plug 62 is rotatably mounted, being secured against endwise removal in an inward direction by shoulders 63, and in an outward direction by the lock operator cam 64.

In this instance, a pair of vertically spaced-apart machine screws 65 maintain the lock operator cam 64 in the mounted position at the inner end of the plug, the distal ends 66 of the screws 65 being threaded into the plug adjacent the front end of the plug, the main body or shank 67 of the screws 65 being smooth throughout the major portion of their length. In this instance, the shank portion 67 of the screws 65 serves as a mounting and guiding track for a series of magnet carrying wafers 68, three being illustrated.

The Wafers 68 are provided with spaced, vertically aligned slots 69, 69 for receiving the shank portions 67, 67 of the screws. As will be best appreciated from a consideration of FIGURE 6, the wafers 68 may move axially of the lock body and, by reason of the over-sized slots 69, are also permitted a degree of up and down movement. The wafers, at their upper perimeter, are preferably provided with magnetic inserts 70, the upper ends of which are of common polarity.

An elongated magnetic insert 71 is secured within a recess 72 formed in the plug 62, the radial inner surface of the elongated insert being of the same polarity as that of the outermost ends of the inserts 70 of the wafers.

As will be readily apparent, the magnetic insert 71 will react against the like poled inserts 70 of the wafers and tend to urge the magnetic elements downwardly within the plug when the elements 68 are shifted rearwardly within the plug. It will be readily recognized that the downward movement imparted to the wafers or elements 68 may be equally well eiTected by spring means.

The wafers 68, in the locked position shown in FIG- URE 4, are preferably maintained in spaced relation by a series of short coil springs 73, 74 interposed between the interfaces of adjacent wafers, the springs being sleeved about one of the retainer guide screws 65. An elongated spring 75 is disposed about the main shank portion 67 of the screws 65 and biases all of the wafers 68 toward the front (outer) end of the lock. As will be noted from FIGURE 4, the spring 75 mantains the wafers 68 clear of the locking one or area which is disposed rearwardly of the wafers.

Locking action in the embodiment of FIGURES 4 to 6 is achieved by a series of magnetically controlled pins corresponding to the number of wafers employed. As best appreciated from FIGURE 6, the magnetic locking pin assemblies are quite similar to the locking assembly of the prior embodiment.

The lock assemblies are contained within a laterally directed enlargement 80 formed in the housing, which enlargement includes a radially extending cross bore 81 aligned in registry with a complemental cross bore 82 formed in the plug. Each of the cross bores 81 is provided with a follower pin 83 which is pressed across the shear line SS defined between the plug and the housing by driver springs 84. The innermost ends 85 of the driver springs are biased against the outer ends of the pins 83, the outer ends 86 of the pins being pressed against a dovetailed slide or capping member 87 disposed within an undercut slot 88 formed in the enlargement 80.

Magnetic pins 89 are disposed within bore portions 82 formed in the plug. The pins 89 may include an enlarged head 90 and a reduced inner end portion 91, the shape of the pins and cross bore conforming generally to each other as in the prior embodiment. The pins 89 are constructed so that the innermost and outermost ends of the pins define magnetic poles. While in FIGURE 6 the inner end of the pin is shown to define a north pole and the outer end a south pole, the polarity of the various locking pins may vary at random (see FIGURE 4, for instance).

Each of the wafers 68 is provided with a laterally directed recess 92, which recess is filled with a magnetic insert 93. The magnetic inserts 93 of the wafers are polarized so that the outermost surfaces of the inserts are of like and, hence, repelling relation with respect to the magnetic pins 89 which they are intended to operate. The wafers 68 are provided, in addition, with upwardly extended clearance slots 94, to permit passage of a key, the clearance slots being free of the grooving defined by the keyway so as to permit vertical relative movement between the wafers and the key.

The device is operated by the insertion of a key 95. The key 95 may be provided with the usual milling, to define an irregular configuration, and the keyway of the plug, especially at its outermost and innermost ends, may be likewise complementally milled to enable insertion of a proper key and prevent insertion of an improperly milled key.

The key is formed at its upper edge with a series of stepwisely arranged operating shoulders 96, 97, 98, arranged in progressively increasing height when viewed from the tip toward the bow of the key.

The wafers 68 and particularly the uppermost ends 99 of the clearance slots 94, are coordinated with the shoulders of the key and with each other in similar stepwise fashion so that end 99 of the innermost wafer is lower than the end of the central wafer which, in turn, is lower than the end 101 of the slot of the outermost wafer.

As will be evident from FIGURE 5, the stepwise orientation of the shoulders 96, 97, 98 of the key, and ends 99, 100, 101 of the wafers is such as to permit the shoulder 96 to pass beneath without engaging the two uppermost wafers A, B but to engage against a side portion of the innermost wafer C. In like manner, the shoulder 97 will pass beneath wafer A and pick up wafer B, and the outermost shoulder 98 of the key will engage only wafer A.

With the continued insertion of the key 95, the wafers will be carried rearwardly to the interior of the lock and when a proper key is fully inserted, magnetic elements 93 of the wafers will be disposed in precise alignment with the complemental and oppositely polarized inner ends of the magnetic pins 91. When this position of the wafers is achieved, the magnetic pins 89 will be shifted outwardly, causing the inner ends of the locking pins 83 to be shifted into alignment with the shear line S-S, thus releasing the plug for rotation relative to the housing.

In considering the security of the above described device, it will be observed that an unlocking of the magnetic pins can be achieved only if the key lifts the wafers to the proper extent and also shifts them inwardly to the proper position along the axis of the plug. By this arrangement, requiring critical heightwise and axial alignment of the wafers, an exceedingly high degree of security is achieved.

Preferably, as set forth in connection with the prior embodiment, the forces of the magnetic elements are accurately balanced to permit the exertion of a force sufficient to release the locking pins only when a precise orientation is achieved between the magnets in the wafers and the magnetic pins.

As further noted in connection with the prior embodi' ment, means may be provided to assure that the magnetic pins are not forced across the shear line and into the housing.

From the foregoing description of two embodiments of magnetic locks, it will become evident that a skilled worker in the art, having the benefits of the teachings hereof, could devise a multiplicity of different forms of locks using magnetic carrier elements shifted by the insertion of keys, without the exercise of invention. For example, the wafers or other magnetic carriers may be mounted for pivotal as well as axial movement about a single support post carried by the lock plug. Similarly, a double bitted key may be used to shift the magnetic carrier elements in opposite directions upon insertion of the key, locking means being provided at opposed portions of the housing.

While the embodiment of FIGURES 4 to 6 has been illustrated in connection with the use of three locking wafers, it will be readily recognized that the invention is by no means restricted to this number.

From the foregoing description, it will be appreciated that there is provided a high security lock apparatus employing magnetic control elements, which lock apparatus is operable by a key not required to contain any magnetic inserts or components.

Optionally, completely to frustrate picking by any mechanical means, it may be desirable to introduce a magnetically inert film or layer within the lock between the magnetic pins and the keyway, to prevent any mechanical contact with the magnetic pins. Such a layer may require the use of stronger magnetic components and result in a slight increase in cost. However, such increase may be justified in particular applications by the additional security afforded.

Having thus described the invention and illustrated its use, what is claimed as new and is desired to be secured by Letters Patent is:

1. A magnetic lock device comprising a housing having a main bore, a cylindrical lock plug rotatable within the bore of said housing, a keyway formed in said plug, a cross bore extending from said housing into said plug, a first pin mounted in said cross bore, means inwardly urging said first pin across the shear line defined between said plug and housing to lock said plug and housing against relative rotation, a second magnetic pin in said cross bore having an outer end engaging the inner end of said first pin, magnet carrier means movably mounted in said plug and having portions intersecting said keyway, a magnet element on said carrier having repelling properties relative to the inner end of said second pin, means biasing said carrier means to a first position wherein said magnet element is displaced from said cross bore, and key means insertible into said keyway for shifting said carrier from said first position to align said magnet portion with said cross bore.

2. A device in accordance with claim 1 wherein said carrier means is shiftable axially of said keyway responsive to the insertion of a key.

3. A device in accordance with claim 1 wherein said carrier means is shiftable transversely of said keyway responsive to the insertion of a key.

4. A device-in accordance with claim 1 wherein said carrier means is shifted axially and transversely responsive to the insertion of a key.

5. A device in accordance with claim 1 and including auxiliary locking means extending across said shear line, said key including means for releasing said auxiliary locking means.

6. A device in accordance with claim 1 wherein said carrier member is disposed in proximate spaced relation to the innermost end of said keyway and said spring means urges said carrier toward the outer end of said keyway, said key including carrier engaging portions adjacent the lead end thereof for shifting said carrier axially inwardly to said aligned position responsive to insertion of said key.

7. A device in accordance with claim 5 wherein said carrier member is disposed in proximate spaced relation to the innermost end of said keyway and said spring means urges said carrier toward the outer end of said keyway, said key including carrier engaging portions adjacent the lead end thereof for shifting said carrier axially inwardly to said aligned position responsive to insertion of said key.

8. A magnetic lock device comprising a housing having a main bore, a cylindrical lock plug rotatable within said bore, a keyway formed in said plug, at least two cross bores extending from said housing into said plug, first and second locking means movably mounted in said first and second cross bores, respectively, said locking means being yieldably urged across the shear line defined between said plug and said housing, first and second magnetic releasing means disposed in said first and second cross bores, respectively, radially inwardly of said locking means, first and second magnetic carrier means movably mounted in said plug and having portions intersecting said keyway, first and second magnetic element means on said first and second carriers, respectively, having repelling properties relative to the radial innermost ends of said first and second magnetic releasing means, respectively, means for yieldably shifting said carrier means to a normal locking position whereat said first and second magnetic element means are displaced from said first and second magnetic release means, and key means for aligning said first and second magnetic elements with said first and second release means, respectively, thereby to shift said locking means to the plug releasing position thereof.

9. A device in accordance with claim 8 wherein the carrier means are shiftable axially of said plug.

10. A device in accordance with claim 8 wherein the carrier means are shiftable transversely of said plug.

11. A device in accordance with claim 8 wherein the carrier means are shiftable transversely and axially of said plug.

12. A device in accordance with claim 8 wherein said means for shifting said carrier means to said locking position comprise other magnetic portions on said carrier means.

13. A device in accordance with claim 8 wherein said first and second cross bores are radially oifset one from the other.

14. A device in accordance with claim 13 wherein said cross bores are offset by 180.

15. A device in accordance with claim 8 wherein said means for yieldably shifting said carrier means comprise a spring member urging said carriers toward the outer end of said plug.

16. A device in accordance with claim 15 and including variable spacer means interposed between said carrier means and yieldably separating said carrier means.

References Cited UNITED STATES PATENTS 1,093,817 4/ 1914 Williams -42l 1,969,012 8/1934 Jacobi 70--360 2,370,800 3/1945 Kind et al 70-352 3,216,230 11/1965 Falk 70-421 3,420,077 1/ 1969 Drazin 70-276 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R. 7035 6, 421

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