EP3004494B1

EP3004494B1 - Electric lock

Info

Publication number: EP3004494B1
Application number: EP13747527.3A
Authority: EP
Inventors: Fausto Fustini
Original assignee: CISA SpA
Current assignee: CISA SpA
Priority date: 2013-05-27
Filing date: 2013-05-27
Publication date: 2020-02-26
Anticipated expiration: 2033-05-27
Also published as: EP3004494A1; WO2014192032A1

Description

The present invention relates to an electric lock adapted for any type of application.
It is known to use electric locks, or rather electrically-actuated locks, to control accesses.
In particular, this type of lock is used in gates, main doors and access passages through which clearance for passage is required.
It is known to resort to electric locks whenever it is necessary to make it possible to open a door, gate and the like by means of a remote control (action on a button or remote control device on the part of a user).
The operation of this type of lock is generally dependent on the presence of an electromagnet and/or a motor which, when supplied with electric current, releases an element that is integral with the latch and which, by way of the action of a respective elastic element, causes its retraction.
This type of device suffers several problems. First of all, it should be noted that the actuators used are rather expensive components that affect significantly the end price of the lock: the electromagnets and electric motors adapted for this type of application in fact must meet some specific dimensional characteristics that increase the complexity of their production, increasing their costs.
Since this is a dynamic component, the electric motor is further subject to failures that cause an interruption of the service of the lock in which it is installed.
The electromagnets also are easily subject to failures in relation to the high sensitivity of the conductors that constitute the windings to the voltage variations that arrive from the line, such as excess voltages caused by atmospheric discharges and/or switching overvoltages.
In order to protect the electric windings (be they those of the electromagnet and/or those of the motor) it is therefore necessary to provide electric locks with protection devices, which increase their costs further.
Moreover, electric locks of the known type are constituted by a plurality of mutually associated components: obviously, this constructive architecture causes a considerable complexity in terms of assembly as well as a large space occupation.
Such large space occupation causes, as a disadvantage, also the impossibility to accommodate electric locks in small cases that are aesthetically consistent with the door, gate or main door for installation.
In some specific installations it is necessary to provide independent electric power supply sources for the locks: any costs to provide an electric line for supplying power to the lock, connected to the mains, would in fact be too high.
In all these cases, one resorts to electric locks provided with electric actuation motors (electric locks with electromagnets are therefore generally excluded). Locks with electromagnets in fact require the electromagnet to be constantly electrically powered, and this leads to a rapid discharge of the battery even if the installed electric lock actually remains unused for a long period.
The electric motor used in electric locks instead is activated only at the request for a change of state on the part of the lock (for example when the opening control is operated). Once the lock has been opened, the power supply of the motor is interrupted and the lock returns autonomously (by way of adapted elastic means) to the closed configuration.
Unfortunately, the electric motor has a high energy consumption that is also associated with limited energy efficiency: it is therefore necessary to provide the corresponding lock with a set of high-capacity batteries.
Such batteries, in addition to being very expensive, are generally rather bulky: in some cases an attempt has been made to reduce space occupation by adopting latest-generation batteries with high performance, but this has caused a considerable cost increase.
Generally speaking, therefore, one can say that electric locks of the known type, intended for independent operation (not connected to the electrical mains) are very expensive, have a limited independence and are subject to unpredictable and sometimes frequent failures.
JP 2000 352239 A discloses a lock element that is supported by a lock body so as to be movable between a locking position and an unlocking position. When the lock element is in the locking position in a locking state, a main locking body fixes the lock element to the lock body by fitting to a main locking part arranged on the lock element. When performing a normal unlocking action, a main shape memory alloy is heated, and the main locking body is separated from the main locking part by returning to a memorized shape. Thus, the lock element is energized and moved toward the unlocking position and is put in an unlocking state.
DE 4203635 A1 and WO 2004/088068 disclose electric locks wherein a bolt is retracted via a pulling action by actuation of a shape memory alloy element.
The aim of the present invention is to solve the problems described above by devising an electric lock that is not connected to the electrical mains and has a long operating independence.
Within this aim, an object of the invention is to devise an electric lock that is not connected to the electrical mains and has particularly low costs.
Another object of the invention is to devise an electric lock that is not connected to the electrical mains and is scarcely subject to failures.
Another object of the present invention is to provide an electric lock that has low costs, is relatively simple to provide in practice and is safe in application.
In accordance with the invention, there is provided an electric lock as defined in the appended claims.
Further characteristics and advantages of the invention will become better apparent from the description of preferred but not exclusive embodiments of the electric lock according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic perspective view of a gate in which an electric lock according to the invention is installed;
Figure 2 is a schematic view of the electric lock of Figure 1;
Figure 3 is a schematic perspective view of a gate in which an electric lock is installed;
Figure 4 is a schematic view of an electric lock not according to the invention;
Figure 5 is a schematic perspective view of a gate in which an electric lock is installed;
Figure 6 is a schematic view of an electric lock not according to the invention;
Figure 7 is a sectional schematic side view of an alternative constructive solution for an electric lock according to the invention.

With particular reference to the Figures 1, 2 and 7, the reference numeral 1 generally designates an electric lock according to the invention.
The electric lock 1 comprises a box-like body 2, provided with at least one front opening for the passage of at least one latch 3 that can move from a retracted configuration to a protruding configuration.
It is specified that between the box-like body 2 and the at least one latch 3, elastic means 4a, 4b, 4c are provided for forcing the at least one latch 3 into one of the above cited extreme configurations.
The lock 1 comprises at least one set of batteries 5 of the commercial type that is connected to at least one electric actuator 6, which is functionally associated with the at least one latch 3 for its movement.
The connection of the set of batteries 5 to the actuator 6 occurs with the interposition of externally actuated means 7 for interrupting electrical continuity.
The actuator 6 is provided with at least one component that is at least partially made of a material of the type of a shape memory alloy (SMA).
The definition of shape memory alloy, SMA, references the family of metallic materials that have the capacity to restore their initial configuration if they are deformed and then subjected to an appropriate thermal treatment. In particular, SMAs undergo a crystalline phase transformation when they are brought from their more rigid configuration at high temperature (austenite) to the configuration at lower energy and temperature (martensite). This transformation is indeed the primary cause of the particular qualities of these alloys; next to the shape memory effect it is further important to mention the phenomenon of superelasticity, which has multiplied the possibilities of use, as well as the particularity of the martensitic phase, which plays a fundamental role in said transformation.
When an SMA is brought to a low temperature, it assumes a configuration of the martensitic type, it has a low yield strength and is easily deformable; as a consequence of heating, the alloy is modified, arranging itself according to another crystalline structure, of the austenitic type, and thus resumes the initial shape and configuration. The temperature at which the alloy "remembers" its primitive form can be modified by means of variations in the composition or by means of appropriate thermal treatments. In the NiTi alloy, for example, said temperature can vary by even 100°C; the shape recovery process occurs within a range of a few degrees.
Although there are countless alloys that have shape memory properties, mainly those that recover considerably the deformation or generate considerable force during phase transition are of interest for the present invention.
Such shape memory alloy component of the actuator 6 is therefore deformable as a consequence of an external force of the type preferably selected between the flow through it of an electric current and exposure to a heat source, from a first inactive configuration, at which the latch 4 is arranged in a configuration in which it protrudes from the box-like body 2 (the door, gate, main door is closed stably), to a second actuation configuration, at which the latch 4 is arranged in a retracted configuration (generally as a consequence of an elastic forcing of at least one of said elastic means 4a, 4b and 4c) into the box-like body 2 (and therefore the door, gate, main door can be opened).
In greater depth, it is specified that the box-like body 2 comprises at least one seat for accommodating the at least one set of batteries 5 and an electric circuit 8 for the connection of the at least one set of batteries to the actuator 6.
At least one of the means 7 for interrupting electrical continuity is arranged along the electric circuit 8.
It should be pointed out conveniently that the means 7 for interrupting electrical continuity are constituted preferably by a normally-open button, a contactor, a remote control switch, a relay, a processor and the like.
In the case of a normally-open button, upon the action of a user on the button, the circuit closes, with consequent supply of electric power to the actuator 6 and retraction of the latch 3 (therefore, the button controls the opening of the door, gate, wing in which the lock 1 according to the invention is installed).
When instead one resorts to a device of the type of a contactor, a remote control switch, a relay, a processor and the like, it is necessary to note that these means 7 for interrupting electrical continuity shall comprise preferably a station 9 for receiving control signals that controls the components of the type of a contactor, a remote control switch, a relay, a processor and the like. In this case it is necessary to provide for the presence of a signal transmitter 10, of the type of a remote control, provided with a control element 11 that can be operated by a user.
Upon the action of a user on the control element (intended to modify its state), the transmitter 10 sends a signal to the receiving station 9, which causes the change of state of the contactor, remote control switch, relay, processor and the like controlled thereby.
According to a specific constructive solution of unquestionable interest in practice and in application, in parallel to the at least one set of batteries 5, in order to recharge it, the electric lock 1 can comprise at least one auxiliary circuit 12, which is affected by an assembly 13 for adjusting the electrical values and leads to a device 14 of the type of a photovoltaic panel and the like.
This embodiment allows to keep the at least one set of batteries 5 constantly charged by means of the electric power supplied daily by the auxiliary circuit 12 (powered by the device 14).
Obviously, in this case the set of batteries 5 must be of the rechargeable type.
In all other cases, the possibility is not excluded to use ordinary batteries of the commercial type (even non-rechargeable ones) for the operation of the lock 1 according to the invention: in these cases it shall be necessary to provide for a periodic replacement of the batteries 5 as part of the normal maintenance operations provided for said lock 1.
According to an example, that no longer forms part of the invention, in accordance with Figures 5 and 6, the box-like body 2 can comprise at least one additional front window for the passage of at least one reloading piston 15.
The piston 15 is generally coupled to a respective bracket 16 for supporting the at least one latch 3, with the interposition of respective elastic means 4c.
In this case, the actuator 6 is constituted by the reloading piston 15, by the elastic elements 4c and by at least one locking pin 17 that is at least partially made of a shape memory alloy.
When the lock 1 is arranged for closure, i.e., when the latch 3 is in a configuration in which it protrudes from the box-like body 2 and the reloading piston 15 is arranged so as to be completely retracted within the box-like body 2, with consequent compression of the elastic elements 4c against the respective bracket 16, the at least one locking pin 17, as a consequence of an external force applied thereto, for the type preferably selected between the flow through it of an electric current and the exposure to a heat source, is deformable from the first inactive configuration, which corresponds to its engagement on the bracket 16 for locking it by friction/interference, to an actuation configuration, which corresponds to its spacing from the bracket 16 (caused by a size contraction of said pin 17) with consequent release of the bracket 16 and corresponding retrograde sliding by way of the action of the elastic elements 4c and consequent retraction of the latch 3 within the box-like body 2.
The pin 17, with particular reference to the example, that no longer forms part of the invention, of Figures 5 and 6, can engage within a recess 18 that is present on the bracket 16.
According to a further constructive solution that is particularly efficient and simple to provide in practice, that is not part of the invention, the at least one electric actuator 6 can be constituted by an element 19 that is made at least partially of a material of the type of a shape memory alloy, interposed between the face directed toward the inside of the box-like body 2 of the latch 3 and a bracket 16 for anchoring and moving the latch 3 that is internal to the box-like body 2.
As a consequence of an external force of the type preferably selected between the flow through it of an electric current and the exposure to a heat source, the element 19 is deformable from an inactive configuration, in which it is longer and at which the latch 3 is arranged in a configuration that which it is shorter and at which the latch 3 is arranged in a configuration in which it is retracted within the box-like body 2.
In particular, it is specified that the element 19, made at least partially of a material of the type of a shape memory alloy, is preferably shaped like an axially-acting helical spring: the contiguous turns of such spring are mutually spaced at the first inactive configuration, in which the element 19 is not subjected to external forces, and face each other and are proximate to each other in the second actuation configuration, in which the element 19 is subjected to external forces.
It is therefore possible to conclude that the latch 3 undergoes a retraction into the box-like body 2 when the element 19 is subjected to a force and therefore contracts.
With particular reference to the constructive solution according to the invention that is safe and simple to apply in practice, elastic means 4a and 4b are interposed between the face directed toward the inside of the box-like body 2 of the latch 3 and its bracket 16 for anchoring and movement inside the box-like body 2.
The at least one electric actuator 6, in accordance with the invention, comprises at least one unit 20, functionally associated with the latch 3, that can move along a predefined stroke by way of the action of a pusher 21 that is made at least partially of a material of the type of a shape memory alloy.
The stroke of the unit 20 in this case is defined between two extreme arrangements, a first arrangement that corresponds to the latch 3 protruding from the box-like body 2 by way of the action of the elastic means 4a and 4b and a second arrangement that corresponds to the latch 3 being retracted within the box-like body 2 in contrast with the elastic means 4a, 4b (by way of the action of the pusher 21).
It should be noted that this constructive solution is provided effectively by adopting a movable unit 20 constituted by a lever that is pivoted on the box-like body 2. In this case the lever has an arm 22 that is associated with the latch 3 and the opposite arm 23 that is associated with the pusher 21.
When the pusher 21 (at least partially made of shape memory alloys and/or materials having similar physical properties) is not subjected to a force (therefore is not crossed by an electric current and/or is not exposed to a heat source), its length is minimal and therefore it does not act on the arm 23 of the lever: the latch 3 therefore continues to protrude from the box-like body 2 by way of the action of the elastic means 4a, 4b.
When instead the pusher 21 has a force applied thereto (and is therefore crossed by an electric current and/or exposed to a heat source), its length increases and therefore it acts on the arm 23 of the lever, causing a rotation thereof that causes the backward motion of the latch 3 until it retracts completely inside the box-like body 2.
A possible alternative practical embodiment of the constructive solution according to the invention described above, comprising the movable unit 21, is the one that provides it by means of a slider that can slide along a guide defined on the box-like body 2.
In this case, the slider has a first portion that is associated with the latch 3 and a second portion that is at associated with the pusher 21.
The length variations of the pusher 21, caused by the physical properties of the material of the type of shape memory alloys that constitute it at least partially, as a consequence of the external stresses described earlier, produce movements of the slider with consequent entrainment of the latch 3 (in contrast with the thrust of the elastic means 4a, 4b).
It is convenient to specify that in all the provided cases the electric actuator 6 is associated with the respective circuit 8 comprising the set of batteries 5: the flow of electric current can affect directly the component made of a material of the type of shape-memory alloys or can pass through a heater (such as for example a resistance heater) that faces such component, which, by overheating due to the Joule effect, applies a force to the component.
The actuator 6, according to some possible applications that can be implemented easily, therefore can comprise at least one heater of the type of an electric resistor and the like that faces and is proximate to the at least one component at least partially made of a shape memory alloy in order to subject it to a force of the thermal type, such as a heating.
It is specified that the shape memory alloys of predominant interest for the application of the present invention are those of the type preferably selected among copper-zinc alloys, nickel-titanium alloys, silver-cadmium alloys, gold-cadmium alloys, copper-aluminum-nickel alloys, copper-tin alloys, indium-titanium alloys, nickel-aluminum alloys, iron-platinum alloys, manganese-copper alloys, iron-manganese-silicon alloys, and the like.
Even if one decides to use an electric lock 1 with rotating latch 3, it is in any case possible to use a pusher 21 made of a shape memory alloy.
All the proposed constructive solutions show monostable operation: i.e., the latch 3 is forced by way of the action of respective elastic means into the configuration that corresponds to its protrusion and therefore is stable only in this configuration.
An external disturbance (which corresponds for example to the abutment of the latch 3 on a surface of the respective selvage) causes the instantaneous retraction of the latch 3, which then returns to the stable protruding configuration.
In this transient step of retraction of the latch 3, ballistic reloading of a system of springs is possible (for example by means of the piston 15 of Figure 6 and/or by means of the retrograde rotation of the rotating latch 3 of Figure 3) and can be released by means of a mechanical action performed by the actuator 21.
The simplicity of this constructive solution is evident, since it does not require the presence of an electric motor dedicated to the movement of the latch, which in this case would be bistable, in the two extreme configurations of maximum and minimum protrusion from the box-like body 2, since only the actuation of such motor might allow the change of configuration (both configurations are stable when the motor is not active).
A lock with bistable latch necessarily requires the presence of a motor that has a high energy consumption; a lock with monostable latch 3 according to the invention, by ensuring its own operation only by means of an actuator 21 made of shape memory alloy (optionally aided by respective elastic means and corresponding reloading elements), has a substantially negligible energy consumption: it is therefore particularly adapted to operate with a power supply using batteries 5.
Conveniently, the present invention solves the problems mentioned earlier by proposing an electric lock 1 that is not connected to the electrical mains and has a great operating independence.
This result is achieved by using sets of batteries 5 of the commercial type and actuators 6 that comprise at least one shape memory alloy component, which, by having an extremely low energy consumption, ensure a long duration of the charge of the batteries 5.
Validly, the electric lock 1 not connected to the electric mains, according to the invention, has particularly low costs: the adoption of sets of batteries 5 of the commercial type in fact ensures an enormous reduction in production costs (especially if compared with an electric lock of the traditional type, which requires, for its energy independence, special batteries with extremely high efficiency and with high storable energy).
Efficiently, the electric lock 1, not connected to the electrical mains, is scarcely subject to failures.
The components that constitute it are in fact static and are not subjected to intense forces (of a mechanical, electrical and/or thermal type) and therefore have very long periods of regular (fault-free) operation.
Positively, the electric lock 1 has low operating costs and at the same time is also relatively simple to provide in practice as well as safe in application.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the invention as defined by the appended claims.
In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

An electric lock of the type comprising a box-like body (2), provided with at least one front opening for the passage of at least one latch (3) that can move from a retracted configuration to a protruding configuration, between said box-like body (2) and said at least one latch (3) there being elastic means (4a, 4b, 4c) for forcing the at least one latch (3) into one of said two configurations, the lock further comprising at least one electric actuator (6), functionally associated with said latch (3) for its movement, connection with the interposition of means (7) for interrupting electrical continuity that are actuated externally, said actuator (6) being provided with at least one component that is at least partially made of a material of the type of a shape memory alloy, said component being deformable, as a consequence of an external force of the type preferably selected between passage through it of an electric current and exposure to a heat source, from a first inactive configuration, at which said latch (3) is arranged in a configuration that protrudes from said box-like body (2), to a second actuation configuration, at which said latch (3) is arranged in a configuration in which it is retracted in said box-like body (2), wherein between the face directed toward the inside of said box-like body (2) of said latch (3) and a bracket (16) for the anchoring and movement of said latch (3) that is internal to said box-like body (2) there are interposed said elastic means (4a, 4b), said at least one electric actuator (6) comprises at least one unit (20), which is functionally associated with said latch (3) and can move along a predefined stroke by way of the action of a pusher (21) that is made at least partially of a material of the type of a shape memory alloy, said stroke being defined between two extreme arrangements, a first arrangement that corresponds to said latch (3) protruding from said box-like body (2) by way of the action of the elastic means (4a, 4b), a second arrangement that corresponds to said latch (3) being retracted into said box-like body (2) in contrast with said elastic means (4a, 4b), characterized in that
the lock further comprises at least one set of batteries (5) of the commercial type that is connected to the at least one electric actuator (6); and
said movable unit (20) being:
a lever that is pivoted on said box-like body (2), said lever having an arm (22) that is associated with said latch (3) and the opposite arm (23) that is associated with said pusher (21); or

a slider that can slide along a guide that is defined on said box-like body (2), said slider having a first portion that is associated with said latch (3) and a second portion that is associated with said pusher (21).
The electric lock according to claim 1, characterized in that said box-like body (2) comprises at least one seat for accommodating said at least one set of batteries (5) and an electric circuit (8) for the connection of said at least one set of batteries (5) to said actuator (6), at least one of said means (7) for interrupting electrical continuity being arranged along said circuit (8).
The electric lock according to claim 1, characterized in that said means for interrupting electrical continuity (7) are preferably constituted by a normally-open button, a contactor, a remote control switch, a relay, a processor and the like.
The electric lock according to claim 3, characterized in that said means (7) for interrupting electrical continuity comprise a signal receiving station (9) that controls said component of the type of a contactor, a remote control switch, a relay, a processor and the like, and a signal transmitter (10), of the type of a remote control, provided with a control element (11) that can be operated by a user.
The electric lock according to claim 1, characterized in that it comprises, in parallel to said at least one set of batteries (5) for recharging it, at least one auxiliary circuit (12), which is affected by a unit for adjusting the electrical values (13) and leads to a device (14) of the type of a photovoltaic panel and the like.
The electric lock according to one or more of the preceding claims, characterized in that said actuator (6) comprises at least one heater of the type of an electric resistor and the like that faces and is proximate to the at least one component at least partially made of a shape memory alloy in order to subject it to a force of the thermal type, such as heating.
The electric lock according to one or more of the preceding claims, characterized in that said shape memory alloy is the type preferably selected among copper-zinc alloys, nickel-titanium alloys, silver-cadmium alloys, gold-cadmium alloys, copper-aluminum-nickel alloys, copper-tin alloys, indium-titanium alloys, nickel-aluminum alloys, iron-platinum alloys, manganese-copper alloys, iron-manganese-silicon alloys, and the like.
The electric lock according to one or more of the preceding claims, characterized in that said at least one latch (3) is monostable, i.e., has a configuration of stable equilibrium at its complete extraction from said box-like body (2), the actions of said elastic means (4a, 4b, 4c) causing the forcing of the at least one latch (3) in said configuration for closure of the lock (1), the action of the at least one electric actuator (6) causing the instantaneous movement of said latch in the opposite open configuration, said latch (3) returning instantaneously to the closed configuration when the action of said actuator (6) ceases.