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An electric lock for a cylinder lock of the type in which a knob inside the
door is mounted on a lock case so as to be capable of being turned at will
and a knob is rigidly fixed outside the door, and in which the latch is
unlocked either by turning the knob inside the door or by operating the
cylinder lock incorporated in the knob outside the door. The electric lock
has a solenoid which controls the motion of a locking piece for the
purpose of blocking the latch from being unlocked by the operation of the
Primary Examiner: Craig, Jr.; Albert G.
Attorney, Agent or Firm:Wenderoth, Lind & Ponack
What is claimed is:
1. A key operated electric door lock comprising:
a lock body mounted through the door;
locking means within said lock body for maintaining said door lock in the locked condition;
a rotatable inside door knob operatively connected to said locking means for unlocking said locking means and unrestricted from unlocking said locking means at all times, whereby turning said inside door knob unlocks said locking means from the
a stationary outside door knob connected to said lock body outside the door;
key operated cylinder lock means within said outside door knob operatively connected to said locking means for unlocking of said locking means from the outside, whereby turning the proper key in the cylinder lock means will unlock said locking
means from outside the door; and
movable solenoid means within said door knob extending therefrom toward said locking means, said solenoid means having a first position when energized and a second position when de-energized, for engaging with and blocking said cylinder lock
means when in one of said two positions, thereby preventing unlocking of said locking means from outside of the door solely by operation of said cylinder lock means, and for disengaging from and freeing said cylinder lock means when in the other of said
two positions, thereby allowing unlocking of said locking means by said cylinder lock means.
2. A door lock as claimed in claim 1, wherein said locking means is comprised of:
a spindle attached inside said inside door knob extending into said lock body;
a rotatable retractor within said lock body engageable with said spindle;
a movable latch for holding said door in the locked position engageable with said retractor, whereby rotating said inside door knob will cause said spindle to turn and contact said retractor, causing said retractor to engage and release said
latch, thus unlocking said door from the inside; and
an actuator attached to said cylinder lock means at one end extending into said lock body for engaging said retractor at the other end thereof having a slot therein open at the end near said retractor, whereby rotating said cylinder lock means
with the proper key will rotate said actuator to engage with said retractor, thereby rotating said retractor and releasing said latch, thus unlocking said door from the outside;
wherein said lock body has a guide grove therein; and
wherein said solenoid means is comprised of
an exciting coil within said spindle;
a core within said coil at the end nearest said inside door knob;
a spring within said core;
a non-rotatable plunger slidably fitted for back and forth movement within said coil, biased by said spring, and extending beyond said coil toward said cylinder lock means;
a non-axially rotatable locking piece rigidly attached to said plunger for movement therewith located at the end nearest said cylinder lock means slidably engaged with the slot in said actuator and the guide groove in said lock body, thereby
restricting axial rotation of said locking piece and said plunger, and whereby energizing said coil with electricity will magnetize said core and attract said plunger with said lock piece attached thereto out of said slot in said actuator along said
guide groove, thereby permitting said actuator to rotate and engage said retractor.
3. A door lock as claimed in claim 2 further comprising a self-actuating locking piece switch back means fitted within said actuator and engaged with said plunger at the end thereof next to the side of said locking piece nearest said cylinder
lock means for retaining said plunger and locking piece intermittently in the position where the locking piece is engaged in the slot in said actuator, so that the actuator is not free to rotate, and intermittently in the position where the locking piece
is outside the slot of the actuator, so that the actuator is free to rotate and engage said retractor.
4. A door lock as claimed in claim 2, wherein said core is made of a ferro magnetic substance, whereby magnetizing said core by running electrical current through said coil will cause said plunger and said locking piece to be drawn away from the
slot in said actuator and maintained in the unlocked position, and whereby reversing the current in said coil will release the magnetic attraction of said core and will allow said spring-biased plunger and said locking piece to return to the locking
position within the slot in said actuator.
The present invention relates to an electric lock wherein unlocking is effected by a conjoint action of a mechanical means operating a cylinder lock
and an electrical means operating a solenoid.
Generally, the doors of such as the guest rooms of a hotel, or the like, where it is required to preserve secrecy and to maintain security, are provided with a cylinder lock which serves the purpose of preventing crimes much better than other
kinds of door locks. And yet, the conventional types of cylinder door locks have a disadvantage in that, since such can be unlocked by operating with a fitting key, whoever is in possession of a fitting key can go into and out of the room, hence if the
key is stolen or if it is duplicated, it is impossible to prevent crimes.
The first object of the present invention is to provide a door lock wherein a solenoid is used, that is to say, an electric lock offers a remedy for the structural shortcoming of the conventional types of cylinder doors locks, as aforementioned,
and which excels in the function of crime prevention.
Another object of this invention is to provide an electric lock which even a person who is in possession of a fitting key cannot unlock by merely operating the cylinder lock incorporated into it but can unlock only when he has obtained consent to
open the door from a third party, hence it is highly effective in the prevention of crimes.
Still another object of this invention is to provide an electric lock with which, by the combined use of a reading equipment such as a card reader, etc., it is possible to put into practice manless management of buildings, apartment houses etc.,
thus well serving the purpose of preventing crimes.
The fourth object of the present invention is to provide an electric lock of the type of a cylinder lock generally used as the door lock.
While these objects are achieved by improvements, combinations and operation of the parts and components of the lock which constitutes the present invention, an embodiment of the invention will be clarified in further details by the annexed
drawings and a detailed description hereunder set forth.
According to the present invention, in a cylinder lock of the type wherein the knob inside the door is rotatably mounted on to the lock case while the knob outside the door is rigidly fitted on to it and the retractor inside the lock case is
either worked by turning the knob inside the door or worked, through the medium of an actuator, by the operation of a cylinder lock incorporated in the knob outside the door, thereby unlocking the latch, the lock is further provided with the following: a
solenoid fitted inside the spindle which is an integral part of the knob inside the door and a locking piece which, being fitted on to the point of a plunger of the solenoid, is supported by a guide groove provided in the bearing which is an integral
part of the lock case, slides along the groove in an unrotatable state, and is capable of being engaged with and disengaged from a slot provided in the aforesaid actuator.
In the accompanying drawings:
FIG. 1 is a side longitudinal section of an electric lock in accordance with the present invention, in its locked state;
FIG. 2 is its side longitudinal section, in the unlocked state;
FIG. 3 is a diagram showing the electric circuit for the operation of the said electric lock; and
FIG. 4 shows a block diagram for the control, with the use of a card reader, of the above-mentioned electric lock.
FIG. 5 is an oblique view of disassembled self-maintaining device which maintains the locking piece in either the locking or unlocking position.
FIG. 6 is a sectional view of the self-maintaining device maintaining the locking piece in the locking position.
FIG. 7 is a sectional view of the self-maintaining device maintaining the locking piece in the unlocking position.
Following is an explanation, with reference to the drawings, of the present invention in further details:
A cylinder lock 10 which is to constitute the present invention is of the type wherein, of the two knobs fitted on to a lock case 11, a knob 12, which is inside the door, is capable of being turned while a knob 13, which is outside the door, is
not capable of being turned, that is to say, is in a fixed state. When the knob 12 inside the door is turned, a spindle 14, which is an integral part of the knob, turns and the hook at the end of the spindle works a retractor 15, thereby unlocking a
latch 16; while, when a key K is inserted into a cylinder lock 17, which is incorporated in the knob 13 outside the door, and the plug is turned, an actuator 19 is turned by a connecting rod 18 which directly connects with the plug and the hook at the
point of the actuator works the retractor 15, thereby unlocking the latch 16. A solenoid 20 is composed of an exciting coil 21, a core 22, a plunger 23 and a spring 24 which gives an impetus to the plunger in the direction it pushes out, and is so
fitted inside the spindle 14 that the end of the plunger 23 passes through the lock case 11 and reaches out in the direction of the knob 13 outside the door. The end of the plunger 23 is fitted with a locking piece 25 which, when the said plunger pushes
out, engages with a slot 19' provided in the actuator 19. The said locking piece 25 is so disposed, by a guide groove 26' provided in a bearing 26 which is an integral part of the lock case 11, as not to rotate round the axis; and when the locking piece
25 is engaged with the slot 19' of the actuator 19, it becomes impossible for the actuator to turn.
Now, in a locked state as shown in FIG. 1, the plunger 23 is being pushed out by the force of the spring 24 and the locking piece 25 at its end is engaged with the slot 19' of the actuator 19; therefore, even if one tries to turn the plug of the
cylinder lock 17 by inserting the key K into it, the retractor 15 will not work because the actuator 19 is not permitted to turn, hence it is impossible for him to unlock the latch 16. Since, on the other hand, there is no restraint on the knob 12
inside the door, it is possible, from within the room, to unlock the latch 16 by simply turning the knob 12 and, thus, to open the door.
Then again, in a state as shown in FIG. 1, the exciting coil 21 of the solenoid 20 is switched on and the core 22 is excited, and then the plunger 23 is attracted by the core 22 and makes a retreat, resisting the resilient force of the spring 24,
thus the locking piece 25 is disengaged from the slot 19' and, as shown in FIG. 2, the actuator 19 is released from restraint by the locking piece 25.
Therefore, when the key K is inserted into the plug and turned, the actuator 19 turns in company with the plug and works the retractor 15, thereby unlocking the latch 16. When the exciting coil 21 is switched off and the core 22 is released from
excitement, the plunger 23 is pushed out by the force of the spring 24 and the locking piece 25 is engaged again with the slot 19' of the actuator 19, thus a locked state, as shown in FIG. 1, being resumed.
Since, as has been described above, it is so devised that the motion of the actuator which is to be caused by the operation of the cylinder lock to work the retractor is controlled by the action of the solenoid, even though a person is in
possession of a fitting key, he cannot unlock the latch by merely operating the cylinder lock but can do so only when such operation is done conjointly with turning on electricity to the solenoid.
Accordingly, if it is so arranged that, as shown in FIG. 4, commands for switching on the solenoid are sent out from the caretaker's room of a building, it will be absolutely necessary for a person wishing to enter a room to obtain the consent of
the caretaker; hence, even if the key has been stolen or has been duplicated, an outrageous intrusion into the room will be prevented, thus going far towards prevention of crimes. Since, on the other hand, the latch can be unlocked by simply turning the
knob from within the room, safety at the time of emergency is also ensured, for the lock offers no obstacle to escape from the room. Besides, when there are provided a microswitch SW.sub.1 which is set "ON" or "OFF" interlocked to the motion of the
locking piece and another, SW.sub.2, which is set ON or OFF interlocked to the opening and closing of the door, and they are respectively connected to a lamp L and a buzzer B, it is possible to watch, at the caretaker's room, locking and unlocking of the
latch by whether the lamp L is on or off and opening and closing of the door by the sound of the buzzer B, thus permitting a centralized control of many rooms for the purpose of crimes prevention.
According to the present invention, furthermore, if it is so arranged that commands for switching on the solenoid are sent out by means of a card reader, nobody but a person who is in possession of both the key of the room and the card can enter
a room. For example, a card reader is installed at the entrance of a buliding, and it is so arranged that the solenoid of an electric lock, in accordance with the present invention, with which the door of each room is provided is switched on by the
action of the said card reader as soon as the porch door is opened; then only a person who can pass the porch will be able to open the door of his own room with his own key. Utilization of the electric lock of this invention in the aforementioned manner
will permit a manless management of buildings, apartment houses and the like.
It is to be noted that there is no limitation in respect of places where the electric lock in accordance with the present invention may be used. Its utilization in combination with other machinery and instruments will go far towards saving
manpower in the management of hotels, buildings, apartment houses and so forth.
Reference is now made to FIG. 5, which is an exploded, oblique view of a self-acting locking piece switchback device 30 which keeps the locking piece 25 in locked and unlocked positions intermittently. The device is constituted of an operating
ring 31 of which the inside is circumferentially provided with a number of protrusions 31.sub.A having a tapered surface 31.sub.a ; a stopper ring 32 which is circumferentially provided with a series of a group of slots and tapered surfaces, namely, a
deep slot 32.sub.A, a shallow slot 32.sub.B and, in continuity with the said shallow slot 32.sub.B, an inwardly tapered surface 32.sub.a and an outwardly tapered surface 32.sub.b ; and a rotor 33 which is so fitted at the end of the plunger 23 as to be
capable of rotating round the axis, with triangular pins 34 rigidly fixed on to its periphery, which is to fit in between the two rings 31 and 32 which are fitted inside the actuator 19.
In a locked state as shown in FIG. 1, the plunger 23 is being pushed outward and is on the inside of the actuator 19; and the pins 34 of the rotor 33, which is provided at the end of the plunger, are fitted into in the deep slots 32.sub.A of the
stopper ring 32. When, in this state, the solenoid 20 is operated and the plunger 23 is made to retreat to an unlocked position, the pins 34 also make a retreat in company with the plunger and, as there are, in the course of their retreat, the tapered
surfaces 31.sub.a of the operating ring 31, the pins 34 hit against such and, by this action, the rotor 33 turns by one pitch and the troughs between the tapered surfaces are reached. When, in this state, the exciting coil 21 is switched off, the
plunger 23 starts to return to a locked position by the force of the spring 24, but, as there are, on the stopper ring 32 and at the positions opposite the troughs between the tapered surfaces as aforesaid, inwardly tapered surfaces 32.sub.a, the pins 34
hit against such tapered surfaces 32.sub.a and, in virtue of their action, turn further to come to fit in the shallow slots 32.sub.B, thereby checking the plunger 23 from moving into a locked position. Therefore, the locking piece 25 is kept in a state
where it is not engaged with the slot 19', namely, in an unlocked state. (FIG. 5)
When, in this state, the solenoid 20 is again made to work and the plunger 23 is made to retreat, the pins 34 hit against the tapered surfaces 31.sub.a, opposite the shallow slots 32.sub.B, of the operating ring 31 and, by this action, the pins
34 (the rotor 33) turn and reach the trough in the next order. When electricity is turned off, the plunger 23 pushes out again; the pins 34 hit against outwardly tapered surfaces 32.sub.b opposite the troughs, turn as they slide along the tapered
surfaces and fit in the deep slots 32.sub.A in the next order, thus a locked state being resumed.
Thereafter, the above-mentioned operation is repeated every time electricity is turned on to the exciting coil, and locking and unlocking are effected intermitently. Since it is just enough to electrify the exciting coil for only one to two
seconds for each operation, there is no possibility at all of a burn-out of the coil occurring.
While, in the present example of the embodiment of this invention, there has been cited a self-acting locking piece switchback device by mechanical means, there is another method to achieve the same purpose. That is to say, the core 22 of the
solenoid 20 is made of a ferromagnetic substance such as ferrite, and the core 22 is alternately magnetized or made free of magnetism, for locking and unlocking, by changing the direction of electric current which is turned on to the exciting coil 21.
It is to be clearly understood that the scope of claims of the present invention is by no means restricted to the aforementioned embodiment thereof but that some variations and modifications come under the scope of claims of the present