Electromagnetic door lock

Abstract

An electrically operated door lock which comprises a housing for mounting the door lock and having a bore on one side thereof and a lock operating mechanism mounted in the housing. The mechanism includes a first electromagnetic means for driving a locking pin through the bore into a "lock" position and a second electromagnetic means for driving the pin into an "unlock" position. A guiding member extends through the locking pin and is adapted upon actuation of the first and second electromagnetic means to lead the pin into the lock and unlock position, respectively.

Description

The present invention relates to an electromagnetically operated door lock of the type which may be used for locking the doors of private or other commercial buildings.

It is a common practice to use manually operated locks for locking doors. Electromagnetically operated locks of known types consist of a bolt or pin which is pushed forward into a recess provided at the edge of a door thus providing the locking means. The bolt is pushed forward by a solenoid and the door remains locked as long as a current flows through the solenoid. A spring attached to the bottom of the pin retracks the pin and thus opens the door whenever the current is disconnected. Such a device does not prove reliable since when the current is cut off due to a breakdown of the local electric supplier, the locking pin is automatically retracted by means of the spring and the door remains unlocked.

It is therefore an object of the present invention to provide an electromagnetic door lock which is safe and reliable and which is so conceived as to keep the door locked even in case of the local electric feeder shutdown.

The door lock mechanism in accordance with the invention comprises a housing adapted to be installed in the jamb of a door, and includes a first electromagnetic means for driving a locking pin through the bore into a lock position and a second electromagnetic means for driving the pin into an unlock position. A guiding member which extends through the locking pin and which, upon actuation by the first and second magnetic means, leads the locking pin into the lock or unlock position. The electromagnetic means are energized only when the locking pin is to be moved into the lock or unlock position and at other times no electrical current flows therethrough.

Other objects of the invention will become more apparent through the following description of a preferred embodiment given in the accompanying drawings, wherein

FIG. 1 shows the electromagnetic door lock as installed in the jamb of a door;

FIG. 2 is an exploded view of the locking mechanism in accordance with the invention;

FIG. 3 is an electrical diagram showing the operation of the electromagnetic door lock;

FIGS. 4, 5 and 6 illustrate the electromagnetic door lock of the invention into operation.

Referring to FIG. 1, a door lock 1 in accordance with the invention is shown as mounted on a door frame-casing 1 or a jamb 2. The jamb 2 is illustrated as being made of aluminum, into a single piece, but it is to be understood that a wooden frame could be alternatively used without departing from the efficiency of the locking device of the invention. As shown, the locking device is mounted flushed to the door frame by means of upper and lower mounting screws 3 according to a technique more elaborately described later with reference to FIGS. 4 to 6. In the indoor side of the door frame 2 is provided a manually actuable lever 5 for manually unlocking the door in the case of an electric shutdown of the local feeder. A locking pin 6 fully retracts upon upwardly actuation of the lever 5 to permit the opening of the door.

The locking mechanism of the electromagnetic door lock of the invention is best seen in FIG. 2 which illustrates an exploded view of such mechanism.

The locking device 1 is constituted of a housing 7 made of aluminum or any suitable material and to which is secured by welding or any other methods a hollow cylindrical metallic member 8 which is provided, for maximum rigidity, with a rim 9 at one end, this rim being attached to the housing 7. The locking pin 6 slides freely through the member 8. This member 8 is also provided with two bores extending each along almost the entire length of the member 8. These two bores are in alignment with each other and substantially following the longitudinal axis of the housing 2 and their width is such as to permit the insertion therein of a pin actuating member 10. The member 10 extends through the pin 6 and has one end attached, mechanically or otherwise, to a plunger 11 of a first magnetic actuator 12 and the other end to a plunger 13 of a second magnetic actuator 12'. The first and second actuators are preferably solenoids. Thus, the member 10 is driven by one or the other of the solenoids each time one of the latters is energized. The full operation of the locking device will be hereafter described with reference to FIGS. 4 to 6.

A lever 5 extending through the member 10 permits to drive the pin 6 inwardly and thereby to manually unlock the door, in case primarily of a failure of the local electrical supply. This lever 5 could be advantageously mounted at the point linking the plunger 13 to the member 10, the lever extending through a groove 14 pierced into the housing 7. It is to be understood that any other location of the lever 5 as long as it performs the manual operation of driving lever 10 to the unlock position may be effected.

Whenever, the pin 6 is in the lock position, that is when the lever 10 after having been attracted by the solenoid 12' through the plunger 13, and at its lowest position, a switch 16, preferably of the micro-switch type, is closed by means of a metallic wire 16' to energize a lamp 26 (FIG. 3) for indicating that the door is actually locked.

The lever 10 and the pin 6 through which the lever extends have been, following a preferred embodiment, particularly designed so as to provide a reliable and full-proof locking condition.

To keep the pin 6 in the unlock position, that is fully inwardly retracted, there is provided a pair of permanent magnets 17 and 19 which prevent the member 10 from falling by gravitation and then unlock the door. For this purpose the magnet 17 is fixed onto the body of the solenoid 12 through a mounting member 18 while the magnet 19, in operating alignment with magnet 17 is fixed to the plunger 11 of solenoid 12 by means of a mounting member 20. Obviously, the coercive force of each magnet has only to be sufficient to overcome the gravitational force acting on the member 10 and the plungers 11 and 13 and must not go beyond the actuating force of the solenoid 12' on the plunger 13, to be effective. Of course, these permanent magnets are necessary only when the locking device is vertically installed, since when horizontally installed, said gravitational force becomes uneffectual.

FIG. 3 shows an electrical diagram for actually operating the locking device illustrated in FIG. 2. A voltage source working at the industrial frequency is connected across the input or primary winding of a step-down voltage transformer T. The secondary winding of the transformer T is connected to a switch S which is preferably of the make-and-break type. When the switch S is pressed upwardly, a current flows through conductive leads 21 and 22, the solenoid 12 and through a return lead 23, thereby unlocking the door. Conversely, when the switch S is pressed downwardly, a current flows through conductive leads 21 and 24, the solenoid 12' and a return lead 23, thereby locking the door. A permanent indication of the lock condition of the door is obtained by means of a lamp 26 which is energized each time the switch 16 is closed owing to a current flowing through lead 25 which is tapped at mid-point of the secondary winding of the transformer T. It is to be noted that all the devices located within the dotted rectangular box shown in FIG. 3 are mounted in the housing 7 while the other elements such as the switch S the transformer T and the lamp are remotely located.

The operation of the electromagnetic locking device in accordance with the invention will now be given with reference to FIGS. 4 to 6 of the drawings. As it can be readily observed from these figures, the particular shape of the member 10 and of the locking pin 6 allows to conceive the locking device of the invention in a very simple but efficient way, with a minimum of elements. The member 10 may be constituted of four sections, segments, or portions, two of which indicated by A and C respectively, are vertical but extrapolated and joined by a section or segment B which makes an angle of about 30.degree. to 60.degree. with the latters. Section D which is at right angle with section or portion C allows proper alignment of the plunger 13 with the plunger 11 for a maximum of operational efficiency and for reducing the cumbersomeness of the locking device. Preferably, the cross section of each section is rectangular and similar. Of course, all these sections are made into a single piece as illustrated. This guiding member 10 is inserted into a groove or passage 27 made in the locking pin 6 for driving the same at the required position. As is apparent from the drawing, the groove or passage 27 includes a pair of parallel inclined surfaces which are aligned with the inclined segment B of the guiding member. As is also apparent from the drawing, the passage also includes a vertical surface 28 which joins one of the inclined surfaces. At the unlock position (FIG. 4), the locking pin 6 is fully retracted and the guiding member 10 is prevented from gravitationally falling by the permanent magnets 17 and 19. As soon as the switch S (FIG. 3) is pressed downwardly, the solenoid 12' is energized and the plunger 13 pulls back the guiding member 10 which drives outwardly the locking pin 6 being, then, slidably moved along segment B of the member 10 as shown in FIG. 5. The pin 6 reaches the lock position when the plunger 13 is fully retracted into the solenoid 12', as shown in FIG. 6. It is to be noted that maximum security is obtained by having the section A of the guiding member partially overlapping and in abutment against the vertically disposed grooved surface 28 of the locking pin 6.

Furthermore, the above-described electromagnetic locking device is mounted perfectly flush with the jamb of a door by means of a linking plate 29 joining the front of the housing 7 to the door jamb by means, for instance, of flat-headed screws 30 and 31.

While a preferred embodiment of the invention has been illustrated and described, it will be understood that changes in the construction may be made within the scope of the appended claims without departing from the spirit of the invention.

Claims

I claim:

1. An electrically operated door lock comprising:

a. a housing for mounting the door lock and having a bore on one side thereof;

b. a locking pin having a longitudinal axis, said locking pin being disposed in said bore for axial movement therein;

c. a lock operating mechanism mounted in said housing, said mechanism including a first electromagnetic means for driving said locking pin through said bore into a lock position and a second electromagnetic means for driving said pin into an unlock position;

d. a guiding member extending through the locking pin and adapted upon actuation of said first and second electromagnetic means to lead said pin into the lock and unlock positions, respectively;

e. said guiding member including first, second, and third sections;

f. said first section having a centerline which is perpendicular to the longitudinal axis of said locking pin;

g. said second section including a segment having a centerline which is inclined at an angle of approximately 30.degree.-60.degree. with respect to the centerline of said first section, said second section extending between said first and third sections to join said first, second, and third sections together;

h. said third section extending from said section and having a centerline which is substantially perpendicular to the centerline of said first section;

i. said first electromagnetic means being coupled with a distal end of said first section;

j. said second electromagnetic means being coupled with a distal end of said third section;

k. said locking pin including a passage, said passage being partially defined by first, second, and third surfaces, said first and second surfaces being parallel to each other and parallel to said inclined centerline of said segment of said second section of said guiding member, said third surface joining said first surface and being disposed perpendicularly to the longitudinal axis of said locking pin and parallel to the centerline of said first section;

l. said inclined segment of said second section of said guiding member engaging said first surface when said locking pin is driven from the unlock position into the lock position, said inclined segment engaging said second surface when said locking pin is driven from said lock position to said unlock position, said first section of said guiding member engaging said third surface in abutting relationship therewith when said locking pin is in the lock position to thereby maintain said locking pin in such position until it is driven therefrom by said electromagnetic means.

2. An electrically operated door lock as claimed in claim 1, wherein said second section of said guiding member further includes a portion having a centerline parallel to said centerline of said first section and perpendicular to the longitudinal axis of said pin, said portion engaging said third surface of said locking pin when said locking pin is in the unlock position.

3. An electrically operated door lock as claimed in claim 1, wherein the first and second magnetic means are solenoids, each being equipped with a plunger attached to an opposite end of said guiding member.

4. An electrically operated door lock as claimed in claim 1, wherein said electromagnetic means are energized through actuation of make-and-break switch.

5. An electrically operated door lock as claimed in claim 1, wherein permanent magnets are provided for keeping the guiding member and thus the locking pin in the unlock position.

6. An electrically operated door lock as claimed in claim 1, wherein the locking pin slides within a cylindrical member defining said bore, the cylindrical member being provided with lengthwise slits so as to allow movement of said guiding member thereacross.

7. An electrically operated door lock as claimed in claim 1, wherein a lever is attached to said guiding member and extends through said housing for manually actuating said pin into the unlock position.

8. An electrically operated door lock as claimed in claim 1, wherein the lock is mounted flush with the jamb of the door by means of a mounting plate, one end of said plate being secured to said housing while the other end is fixed to the door frame.

9. An electrically operated door lock as claimed in claim 1, wherein a remotely located lamp is energized by means of a switch mounted in said housing whenever the guiding member and the locking pin are in the lock position.