Electromagnetic Lock

Abstract

An electromagnetic lock has a frame on one of two relatively movable door members and a strike on the other of the door members. A bolt horizontally pivoted on the frame is withdrawn by gravity and impelled under manual control into projected, strike-engaging position by a first electromagnet effective only when a magnetically responsive switch on one door member and a magnet on the other door member are in proximity. The bolt is held in projected position by a detent withdrawable against gravity by a second electromagnet under manual control. Mechanical operation is also provided, and indicators and alarms show relative position of the lock parts.

Description

Access to enclosures such as buildings controlled by doors is of increasing security importance, and great attention is now being paid to ways of operating door locks from the immediate vicinity of the door as well as from remote points and for affording indications, either in the vicinity of the door or at one or more remote points, of the secure condition of the door. It is of interest to know whether the door is in open or closed position and whether or not the lock on the door is in unlocked or locked condition. It is of importance to be able to lock or unlock the door at will and if authorized. In many remote control situations electrical power is utilized, bringing with it a difficulty during possible power interruptions. In many instances it is also important to have a mechanical operation of the lock structure. This is true in connection with locks controlled from one or both sides of a door, since those with authorized ingress and egress must be accommodated.

It is therefore an object of the invention to provide an electromagnetic lock which is normally electromagnetically actuated but which can also be mechanically operated.

Another object of the invention is to provide an electromagnetic lock operable either in the vicinity of the lock or from a remote location or both.

A further object of the invention is to provide an electromagnetic lock that can be installed in the customary lock location on a door and door frame.

A further object of the invention is to provide an electromagnetic lock utilizing a bolt, with the operation of the bolt in the locking direction being permissible only when the door and door frame are in suitable relationship.

Another object of the invention is to provide an electromagnetic lock that can easily be fabricated of simple parts and without the use of springs.

A further object of the invention is to provide an electromagnetic lock that in general is an improvement over magnetic locks heretofore available .

Other objects together with the foregoing are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIG. 1 is a cross-section on a vertical, intermediate plane through an electromagnetic lock installed in a door frame and door panel;

FIG. 2 is a view comparable to FIG. 1 but showing the parts in a different position of operation;

FIG. 3 is a wiring diagram useful in connection with the electromagnetic lock of the invention, some portions being shown in mechanically diagrammatic form;

FIG. 4 is a view similar to FIGS. 1 and 2 but illustrating a modified form of electromagnetic lock pursuant to the invention;

FIG. 5 is a view on a horizontal plane through a door frame and panel showing an installation of the electromagnetic lock of the invention; and

FIG. 6 is a view, certain portions being broken away, illustrating another form of electromagnetic lock installation pursuant to the invention.

All forms of the electromagnetic lock pursuant to the invention are arranged for installation on a pair of relatively movable, swinging members such as a door frame 6 and a door panel 7. It is customary to have the frame 6 stationary with respect to the surroundings and for the panel 7 to swing on the frame about a vertical axis, but it is also possible to install the structure so that the stationary portion is the panel 7 and the swinging portion is the frame 6. For convenience in description, it is assumed that the frame 6 is stationary and the panel 7 swings with respect thereto. The adjacent faces 8 of the frame and 9 of the panel are substantially parallel and close to each other and are arranged generally tangent to the arc of motion. This arrangement is not essential, however, since the door panel and frame, with slight modification of mounting, can be arranged so that the members 6 and 7 slide with regard to each other. The faces 8 and 9, although remaining parallel to each other, then approach and recede.

In any event and as an example, the frame 6 is cut away to afford room for a strike plate 11 having a strike box 12 integral therewith, the plate and box being securely mounted on the frame 6 by fastenings 13 in the customary way. Mounted on or preferably recessed within the panel 7 is a housing 16, usually of non-magnetic material, secured in position by fasteners 17 that also mount a face plate 18 flush with the surface 9.

On the inside of the face plate 18 is a mounting bracket 21 serving as the support for a pin 22 disposed with its axis horizontal and parallel to the face 9 and at an elevation substantially opposite the strike box 12. Designed to rotate freely on the pin 22 about the axis thereof is a lock bolt quadrant 23 designed to occupy one position, projecting through an opening 24 in the face plate 18 or to occupy another position, an unlocked position, substantially withdrawn within the housing 16 and not projecting from the face plate 18. In its projected position the bolt 23 occupies a portion of the strike box 12 and therefore precludes swinging movement of the relatively movable panel 6 with respect to the frame 7. When withdrawn the bolt quadrant 23 permits relative swinging movement to take place freely.

Pursuant to the invention means are provided for operating the bolt quadrant 23. A bracket 26 is mounted, preferably on the rear of the plate 18, and secures in position a first solenoid coil 27 of usual construction and designed to be connected in an appropriate electric control circuit. Movable within the coil 27 along a substantially rectilinear and vertical axis is a solenoid core 28 adapted to be pulled within the coil 27 when the coil is energized. When the coil is not energized, the core 28 falls by gravity until the bottom of the core 28 lies against a cushion 29 within the housing 16.

At its upper end the core 28 is united with a non-magnetic extension 30 carrying a pivot pin 31 joined to one end of a link 32. At its other end the link 32 is connected by a pin 33 to the bolt quadrant 23. This affords an appropriate articulation between the rectilinearly moving core 28 and the swinging quadrant 23. The disposition and weight of the parts is such that the combined center of gravity thereof is always on the housing side of the support pin 22. When left alone the core 28 falls, the link 32 falls with it, and the quadrant 23 is pulled by gravity into the housing 16 and does not project therefrom. When the coil 27 is energized, then the core 28 is lifted and, through the link 32, turns the quadrant 23 into projected or locked position.

Depending upon the requirements of different installations, the quadrant bolt 23 can be considered to be in a "normal" position either when it is retracted or when it is projected. In the present instance, it is arbitrarily assumed that the quadrant is in its normal position when the coil 27 is not energized and the quadrant is retracted. But in order to hold the quadrant in projected position for an indefinite period after momentary energization of the coil, there is afforded an appropriate latching means. This takes the form of a detent lever 36 journaled about the transverse axis of a pin 37 supported from the plate 18 by a bracket 38. The unbalanced detent lever 36 extends toward the center of the housing 16 and tends to fall. Near its end the lever has a latch surface 39 designed to lie against one of the radial bounding surfaces 41 of the projected quadrant 23 and, when so engaged, mechanically to hold the quadrant projected.

In order to lift the detent lever 36, when desired, against the force of gravity and out of its lowermost latching position, the detent 36 carries a pin 42 also fitting one end of a link 43. At the other end of the link 43 is a pin 44 joined to the lower end of a second solenoid core 46 movable in a generally rectilinear, vertical path substantially in line with the path of the first core 28. The second core 46 by gravity occupies a lowermost position stopped by the lever 36 resting against the arcuate face 45 of the quadrant 23 but is lifted by a surrounding second solenoid coil 47 mounted in a bracket 48 secured to the plate 18 and arranged to be in an appropriate electrical control circuit.

When the solenoid coil 47 is energized, the core 46 is lifted and the detent lever 36 is pulled out of engagement with the quadrant 23, which then falls to its retracted, lowermost position, provided that the coil 27 is not then energized. When the coil 27 is energized and the quadrant 23 is projected, if the coil 47 is then not energized, the detent lever 36 rides on the surface 45 and finally falls in behind the surface 41 by gravity, as shown in FIG. 1, and holds the quadrant projected.

The structure as so far described is operative simply by alternatively energizing either the solenoid coil 27 or the solenoid coil 47. A difficulty may arise in practice, however. In the event the bolt quadrant 23 is made to project and is so held when the door members 6 and 7 are not in close juxtaposition, then the projecting bolt quadrant is in the way when later it is endeavored to make those members come into alignment. That is, although the lock bolt may be projected, the locking function cannot be accomplished unless the door members are in closed position.

For that reason there is provided in the circuit of the solenoid coil 27 a magnetically responsive reed switch 51 mounted on the back of the face plate 18 in position to be influenced by a permanent bar magnet 52 mounted in the strike box 12 and in close juxtaposition with the reed switch whenever the members 6 and 7 are close together. When the panels are apart, the magnet 52 has no effective influence on the reed switch 51, which remains then in its normal, open position. The reed switch 51 is closed only when and while the magnet 52 is close enough to exert a substantial magnetic influence thereon. This occurs only when the members 6 and 7 are in closed or very nearly closed position. If the door panel 7 happens to be ajar when an attempt is made to energize the solenoid coil 27, nothing occurs since the magnet 52 is too far away and the reed switch 51 remains open. The electrical circuit being open at that point, the solenoid 27 cannot be energized and so cannot project the bolt quadrant 23.

It is often important to have an indication of the position of the bolt quadrant; that is, whether it is retracted (unlocked) or projected (locked). This can be done by sensing the quadrant position directly, but I prefer to do it indirectly. The second solenoid core 46 at its upper end is provided with a non-magnetic extension 53 having an opening 54 therethrough to afford a pair of operating or cam members 56 and 57. Disposed between such surfaces is an actuating lever 58 for an electrical switch 59 adapted to be connected in an appropriate circuit. The lever 58 operates the switch 59 so as to afford an indication whether the extension 53 is in its lowermost position, in which event the bolt quadrant 23 is in its projected position, or is in a higher position, in which event the bolt quadrant 23 is retracted or is only temporarily projected while the coil 27 is momentarily energized.

The controlling instrumentalities for the lock can be at remote points, or can be at the lock installation itself. For example, particularly as shown in FIG. 5, there may be mounted on the panel 7 an exterior, key-actuated lock unit 61 and also, if desired, an interior key-actuated lock unit 62. The lock units 61 and 62 can be rotated manually by thumb turn or by the same or by different keys, and in any event at least one lock unit is effective to produce rotation of a lock plug 63 (FIG. 4) having a switch lever contact 64 related thereto and unlocked included in an electrical circuit. On one side of the switch member 64 is a contact 66 including the second solenoid coil 47 in circuit, while on the other side there is a contact 67 included in a circuit with the first solenoid coil 27. Thus as the plug 63 is rotated in one direction (counterclockwise in FIG. 4) to afford contact between the contacts 64 and 67, the solenoid 27 is energized and projects the lock bolt quadrant 23. When the lock plug 63 is moved in the opposite direction (clockwise in FIG. 4), then the contact 64 engages the contact 66. This is effective to energize the solenoid coil 47 and lifts the detent lever 36, so that the lock quadrant 23 moves to unlocked position by gravity.

In the event the electrical power should fail at any time, and if no auxiliary or standby power is then automatically available, means are provided for mechanically operating the lock. For that reason, there extends from the plug 63 a lever 71 having an actuator 72 at one end. This operates with a lost motion connection within a fork 73 mounted on a pivot pin 74. The fork is part of a forked lever 76 extended to lie beneath a cross pin 77 at the upper end of the extension 53.

Formed in the forked lever 76 is a relatively large cross passage 78 within which the upper end of a rod 79 is slidable. There is a stop 81 on the rod 79 just beneath the lever 76. The lower end of the rod 79 is connected by a pin 82 to a forked lever 83 mounted on a fulcrum pin 84 carried by a bracket 86 extending into the housing from the face plate 18. The other end of the forked lever 83 lies underneath the pin 31.

With this mechanism, when either of the key mechanisms 61 or 62 is actuated so that the plug 63 is revolved, rotation of the plug causes simultaneous rotation of the lever 71. If this is in a clockwise direction, then the operator 72, after some lost motion, abuts the lower portion of the fork 73 and lifts the lever 76 upwardly, so that the pin 77 and the extension 53, as well as the solenoid core 46 and the detent lever 36, are lifted. This permits the projecting bolt quadrant 23 to retract by gravity.

Similarly, when the key plug 63 rotates in a counterclockwise direction, as seen in FIG. 4, the operator 72 after some lost motion abuts the upper end of the fork 73, causing the lever 76 to move the stop 81 and the rod 79 downwardly. This rotates the lever 83 in a counterclockwise direction, thus lifting the solenoid core 28 and causing the bolt quadrant 23 to project. The projected bolt is latched by the gravital falling of the detent lever 36, as before.

There is thus provided means either remote from or close to the lock mechanism for actuating the lock either electrically or mechanically. The electrical operation is usually preferred along with the mechanical operation serving as an override. The mechanical linkage is arranged so that the portion of the lever 83 just beneath the pin 31 is relatively heavy, so that the tendency of the mechanical linkage is to lower by gravity to permit the bolt quadrant always to move by gravity to unlocked position. However, the parts are well enough balanced so that there is no tendency forcing the lever 76 to rise.

In the event it is not convenient to mount the lock units 61 and 62 close to the rest of the structure, there is provided, as shown in FIG. 6, an arrangement in which the lock unit 61 as well as the lock unit 62 are connected to the actuating lever 76 This is done by flexible members 91 and 92. These can be considered as insulated wires connecting the local electrical contacts 66 and 67 to the electrical control circuit. The members 91 and 92 can alternatively be considered as sheathed flexible wires (Bowden wires) affording mechanical two-way interconnections with the lever 76. The members 91 and 92 can be both electrical conductors and mechanical operators, so that even at remote locations there can be electrical, or mechanical, or both electrical and mechanical, control of the lock arrangement.

While the electrical connections can be arranged in numerous different ways, a convenient circuit has been provided as set forth in FIG. 3. The ordinary alternating current supply is provided at terminals 101 and 102 joined by conductors 103 and 104 to the primary coil 106 of a transformer 107, there being a master switch 108 in the conductor 104 and also an indicator lamp 109 shunting the primary coil 106. The transformer 107 also has a secondary coil 111 from one side of which a conductor 112 extends to a contact 113 in a manually actuated, spring returned switch 114. This switch is normally open but can be momentarily depressed to join the contact 113 to a contact 116 in a conductor 117. This latter conductor extends to the solenoid coil 27, the other side of which goes to a junction point 118. From this point a conductor 119 extends through an indicator lamp 121 to join the conductor 112. From the junction point 118 a conductor 122 extends to the magnetic reed switch 51 and a conductor 123 goes back to the coil 111. With this part of the circuit, when the button 114 is depressed to close the switch, a circuit is made to the coil 27, provided, but only provided, the reed switch 51 is magnetically closed by the magnet 52 in close proximity thereto. Whenever the switch 51 is closed, however, the indicator light 121 glows, and when the switch 114 is depressed, the glow dims, so that the user can determine that the circuits are effective.

From a junction point 124 in the conductor 112 a conductor 126 extends to another contact 127. A manual push button switch 128, spring returned, bridges from the contact 127 to a contact 129 joined by a conductor 131 to the second solenoid coil 47. The other end of the coil 47 is joined by a conductor 132 to the conductor 123 and thus back to the source. With this circuit, when the button 128 is depressed the contacts 127 and 129 are joined and the coil 47 is energized.

The position of the detent lever 36 is reflected by the position of the switch 59, which is connected by a conductor 133 to the conductor 132 and also is joined by a conductor 134 through a lamp 136 to the conductor 112. When the switch 59 is in its lowermost or latch position, with the bolt 23 correspondingly projected, then the switch 59 is closed and the lamp 136 glows. On the other hand, when the detent lever 36 is lifted by energization of the coil 47 and the lever 58 moves the switch 59 to open position, then the lamp 136 is not lit, thus indicating that the detent 36 is inoperative and that the lock quadrant 23 has moved or is moving to its unlocked position. The arrangement of the various switch connections can, of course, be reversed so that indications of the opposite function are afforded.

Since the contacts 66 and 67 likewise affect the solenoid coils 27 and 47, it is arranged that the contact 67 is joined to the contact 116 by a conductor 137, whereas the contact 66 is joined to the contact 129 by a conductor 138. The contacts 66 and 67 are energized through the contact 64, since a conductor 139 is joined to the junction point 124 in the conductor 112. In this way either the manually depressible switches 114 and 128 can be utilized, or the key-operated units 61 and 62, or both, can be utilized.

Various alarm possibilities or comparable major indicators are also essily provided. A conductor 141 continues from the conductor 139 to a control switch 142 leading to another reed switch 143 close to the reed switch 51 and affected by the magnet 52 in the same fashion as is the switch 51. The reed switch 143 goes to an alarm 144 connected by a conductor 146 to the conductor 132, to complete the circuit. With this arrangement whenever the door panel is closed, the alarm 144 is energized, provided the switch 142 is closed. Just as before, if the reed switch 143 is of the reverse kind, then the alarm 144 sounds only when the door panel is open.

Also connected to the conductor 141 through a switch 147 is a switch 148 mechanically operated and a duplicate of the switch 59. The switch 148 is operated by the extension 53, just as is the switch 59. The switch 148 is joined through an alarm 149 and a conductor 151 to the conductor 132. With this arrangement, whenever the extension 53 is lifted to release the latch 36 and so unlock the door, the alarm 149 can be sounded. By reversing the switch 148, it can be arranged that the alarm sounds whenever the extension 53 is in its lowermost position, holding the bolt quadrant 23 in door locked position.

Claims

What is claimed is:

1. An electromagnetic lock for use on relatively movable door members comprising a frame adapted to be mounted on one of said members; a strike adapted to be mounted on the other of said members; a bolt; means for guiding said bolt on said frame to move between a first position substantially within said frame and a second position projecting from said frame to engage said strike; a first electromagnet mounted on said frame; a first armature movably disposed with respect to said first electromagnet; means for connecting said bolt and said first armature for conjoint movement; means for urging said bolt toward one of said positions; a detent lever; means for guiding said detent lever on said frame for movement between a first location in latching engagement with said bolt when said bolt is in said second position and a second location out of engagement with said bolt; a second electromagnet mounted on said frame; a second armature movably disposed with respect to said second electromagnet; means for connecting said second armature and said detent lever for conjoint movement; means for urging said detent toward one of said positions; means for selectively energizing said electromagnets including a first electrical circuit incorporating said first electromagnet; a magnetically responsive, normally open switch controlling said first circuit and disposed on one of said members; and a magnet disposed on the other of said members effective to close said switch only when said members are close to each other.

2. A lock for use on relatively moving door members comprising a frame adapted to be mounted on one of said members, a strike adapted to be mounted on the other of said members, a bolt, means for guiding said bolt on said frame to move between a first position substantially within said frame and a second position projecting from said frame to engage said strike, means for urging said bolt toward one of said positions, a detent lever, means for guiding said detent lever on said frame for movement between a first location in latching engagement with said bolt when said bolt is in said second position and a second location out of engagement with said bolt, means for urging said detent lever toward one of said locations, operating means movable between a first position and a second position, means controlled by said operating means for moving said bolt against the force of said urging means from one of said positions toward the other of said positions and for moving said detent lever against the force of said urging means from one of said locations toward the other of said locations, and means responsive to the relative position of said members and including one part on one of said members and including another part on the other of said members and spaced from said one part in all positions of said members for controlling the effectiveness of said bolt urging means.