EP2785938B1

EP2785938B1 - Electric lock

Info

Publication number: EP2785938B1
Application number: EP11805982.3A
Authority: EP
Inventors: Fausto Fustini
Original assignee: CISA SpA
Current assignee: CISA SpA
Priority date: 2011-11-30
Filing date: 2011-11-30
Publication date: 2018-04-04
Anticipated expiration: 2031-11-30
Also published as: EP2785938A1; ES2673222T3; WO2013080231A1

Description

Technical Field

The present invention relates to an electric lock of an improved type.

Background Art

The use of electric locks whenever it is necessary to make it possible to open a door, gate and the like by way of a remote operation (the pressing of a button or use of a remote control by a user) is known.
The operation of this type of lock is always subordinate to the presence of an electromagnet which, when its electrical windings are crossed by a current, releases a moving element that is integral with the spring latch and which, by the action of a respective elastic element, causes the retraction thereof.
This type of device is associated with several problems. In the first place it should be pointed out that electromagnets are rather expensive components that have a considerable influence on the final price of the lock. Conventional electric locks normally have substantially high costs (when compared to the application for which they are intended).
Moreover, electromagnets are highly prone to failure owing to the high sensitivity of the conductors constituting the windings to variations in voltage originating from the line, such as the overvoltages caused by atmospheric discharges and/or switching impulses.
In order to preserve the electrical windings it thus becomes necessary to equip electric locks with protection devices which further increase the costs thereof.
Moreover, conventional electric locks are constituted by a multiplicity of mutually associated components. Naturally such an implementation architecture determines a considerable level of complexity in terms of assembly, as well as a greater encumbrance.
Greater encumbrances entail the added disadvantage that it is impossible to accommodate electric locks in small cases that are aesthetically consistent with the installation door, gate or main door.
WO 2004/088068 discloses an electric lock comprising a box-like body, provided with a front opening for the passage a spring latch, which is movable from a retracted configuration to a protruding configuration, wherein it comprises an electrical actuator, which is functionally associated with the spring latch for the movement thereof. The actuator is provided with one component at least partially made of a material of the type of a shape memory alloy, which is deformable, following an external stress of type selected from the passage of an electric current through it and exposure to a heat source, from a first inactive configuration, in which the spring latch is arranged protruding from the box-like body, to a second configuration of actuation, in which the spring latch is arranged retracted into the box-like body.
DE 3720550 A1 discloses a multiple-locking device, in which there are provided bolts which are displaceable parallel to the plane of the door leaf and engage on at least two mutually opposite sides into corresponding locking plates on the door frame and the release of which takes place by means of a central mechanical or electronic lock.
DE 3632089 A1 discloses a latch lock, in which the latch can be retracted into the lock case as a result of a rotational movement of the pawl shaft. The latch extension consists entirely or over a part length of a metal having form memory (biometal), and that, during the rotational movement of the pawl shaft, a contact is closed for a supply of current into this metal, so that the latch extension experiences a shortening which causes the retraction of the latch.
DE 4203635 A1 discloses a large force electric bolt for a door, comprising a memory alloy drive which is a cold formed metal strip acting directly on the locking bolt.
EP 0 566 881 A1 discloses an electric lock comprising a box-like body, provided with a front opening for the passage of a spring latch and an electrical actuator, which is functionally associated with the spring latch for the movement thereof. The lock further comprises a front window for the passage of a rearming piston, which is coupled to a corresponding bracket for supporting the spring latch, with the interposition of elastic elements. The actuator is constituted by the rearming piston, by the elastic elements and by a locking pawl, which, when the lock is in the closed position, is engaged on said bracket for the locking thereof. The pawl is retained in the blocking position by a pivoting lever, which is subjected to the action of an electromagnet installed in the casing.

Disclosure of the Invention

The aim of the present invention is to solve the above-mentioned problems, by providing an electric lock that is substantially low-cost.
Within this aim, an object of the invention is to provide an electric lock that is less prone to failures, in particular being adapted to withstand any overvoltages owing to atmospheric discharges and/or to switching maneuvers on the power supply electricity line.
Another object of the invention is to provide an electric lock that is constituted by a low number of simple components.
Another object of the invention is to provide an electric lock that has reduced encumbrances.
Another object of the invention is to provide an electric lock that offers an aesthetic appearance which is essential and of minimal visual impact.
Another object of the invention is to provide an electric lock that ensures an installation which is simpler than that of conventional electric locks.
Another object of the present invention is to provide an electric lock which is low-cost, relatively easily and practically implemented and safely applied.
This aim and these objects are all achieved by an electric lock of the type comprising a box-like body, provided with at least one front opening for the passage of at least one spring latch which is movable from a retracted configuration to a protruding configuration, comprising at least one electrical actuator, which is functionally associated with said spring latch for the movement thereof, said actuator being provided with at least one component at least partially made from a material of the type of a shape memory alloy, said component being deformable, following an external stress of a type preferably selected from the passage of an electric current through it and exposure to a heat source, from a first inactive configuration, in which said spring latch is arranged protruding from said box-like body, to a second configuration of actuation, in which said spring latch is arranged retracted into said box-like body characterized in that said box-like body comprises at least one front window for the passage of at least one rearming piston, said piston being coupled to a corresponding bracket for supporting said at least one spring latch, with the interposition of respective elastic elements, said actuator being constituted by said rearming piston, by said elastic elements and by at least one locking pin at least partially made of a shape memory alloy, said at least one locking pin, when the lock is in the closed position, corresponding to said at least one spring latch in the configuration protruding from the box-like body and said at least one rearming piston completely retracted within said box-like body and said elastic elements compressed against the corresponding bracket, being, following an external stress of the type selected from the passage of an electric current through it and exposure to a heat source, deformable from the first inactive configuration, corresponding to its engagement on said bracket for the locking thereof by friction/interference, to a configuration of actuation, corresponding to its removal from the bracket with consequent freeing thereof and corresponding retrograde sliding by the action of said elastic elements and consequent reentry of said spring latch within said box-like body.

Brief description of the drawings

Further characteristics and advantages of the invention will become more apparent from the description of a preferred, but not exclusive, embodiment of the electric lock according to the invention, which is illustrated by way of non-limiting example in the accompanying drawings wherein:

Figure 1 is a partially sectional schematic side view of a first possible embodiment of an electric lock according to the invention;
Figure 2 is a partially sectional schematic side view of a second possible embodiment of an electric lock according to the invention;
Figure 3 is a schematic view of the components of a possible embodiment of an electric lock according to the invention.

Ways of carrying out the invention

With reference to the figures, the reference numeral 1 generally designates an electric lock.
The electric lock 1 comprises a box-like body 2, provided with at least one front opening 3 for the passage of at least one spring latch 4 which is movable from a retracted configuration to a protruding configuration.
The spring latch 4 is designed to engage in an opening which is integral with the jamb so as to ensure the stable closure of the door, gate and/or main door with which the electric lock 1 is associated.
The lock 1 comprises at least one electrical actuator 5, which is functionally associated with the spring latch 4 for the movement thereof.
The actuator 5 is conveniently provided with at least one component at least partially made from a material of the type of a shape memory alloy.
Such a component is therefore deformable, following an external stress of a type selected preferably from the passage of an electric current through it and exposure to a heat source, from a first inactive configuration, in which the spring latch 4 is arranged protruding from the box-like body 2 (the door, gate, or main door is stably closed), to a second configuration of actuation, in which the spring latch 4 is arranged retracted into the box-like body 2 (and therefore the door, gate, main door can be opened).
The term "shape memory alloy", more commonly indicated as SMA, is used to mean the family of metallic materials that possess the capacity to return to their initial configuration if they are deformed and then subjected to a corresponding thermal treatment. In particular, SMAs undergo a crystalline phase conversion when they are brought from their more rigid configuration at high temperatures (Austenite) to their configuration at lower energy and temperatures (Martensite). Such a conversion is in fact the first cause of the peculiar qualities of these alloys. However, in addition to the shape memory effect we must also cite the phenomenon of superelasticity, which has multiplied the possibilities for use, as well as the peculiarity of the Martensitic phase, which plays a fundamental role in the transformation itself.
When an SMA is brought to low temperatures, it takes on a structure of the Martensitic type, possesses a low yield limit and is easily deformable. After heating, the alloy is modified, arranging itself in a different crystalline structure, of the Austenitic type, and thus resumes its initial structure and shape. The temperatures at which the alloy "remembers" its original shape can be modified by way of variations of the composition or with suitable thermal treatments. In the NiTi alloy, for example, such a temperature can vary by as much as 100°C. The process of recovery of the shape occurs in a range of a few degrees.
Although innumerable alloys exist that offer the "shape memory" property, of interest for the present invention are mainly those that considerably recover the deformation or generate a considerable force during the phase transition.
According to a possible embodiment of undoubted practical interest, which can be implemented by way of example in conformance with Figures 1 and 2, the box-like body 2 comprises at least one front window 6 for the passage of at least one rearming piston 7.
The piston 7 is coupled to a corresponding bracket 8 for supporting the at least one spring latch 4, with the interposition of respective elastic elements 9.
The actuator 5, in such case, will be constituted by the rearming piston 7, by the elastic elements 9 and by at least one locking pin 10 at least partially made of a shape memory alloy.
When the lock 1 is in the closed position, i.e. when the spring latch 4 protrudes from the box-like body 2 and the rearming piston 7 is completely retracted into the box-like body 2 with consequent compression of the elastic elements 9 against the corresponding bracket 8, the at least one locking pin 10 is, following an external stress thereof of the type preferably selected from the passage of an electric current through it and exposure to a heat source, deformable from the first inactive configuration, corresponding to its engagement on the bracket 8 for the locking thereof by friction/interference, to a configuration of actuation, corresponding to its removal from the bracket 8 (owing to a size contraction of the pin 10) with consequent freeing of the bracket 8 and corresponding retrograde sliding, by the action of the elastic elements 9 and consequent reentry of the spring latch 4 into the box-like body 2.
The pin 10, with particular reference to the embodiment of Figure 1, can engage a recess 11 provided on the bracket 8.
Similarly the pin 10, with particular reference to the embodiment of Figure 2, can engage a tooth 12 of an oscillating lever 13 which is adapted to lock a sleeve that accommodates the elastic elements 9 and is coupled to the bracket 8 that is integral with the spring latch 4.
Upon the closing of the leaf on which the lock 1 is installed, the piston 7 reenters the box-like body and compresses the elastic elements 9, while the spring latch 4 protrudes from the body 2 thus engaging a corresponding opening.
The bracket 8 is locked in this position as a result of the presence of the pin 10 inside the respective recess 11.
When the pin 10 is subjected to a stress it will contract, thus leaving the recess 11 and freeing the bracket 8. The bracket 8 can then retract by the elastic action of the elements 9 thus also making the spring latch 4 retract into the box-like body 2.
It should be noted that, in all the cases provided for, the electrical actuator 5 will always be provided with respective terminals 20 for connection to a low/ultralow voltage electric power supply circuit: the flow of electric current will be able to directly affect the component made of a material of the type of shape memory alloys, or it can cross a heater (such as for example a resistor), facing the component itself, which by overheating owing to the Joule effect will stimulate the component.
The actuator 5 can therefore, according to some applications that can be easily implemented, comprise at least one heater of the type of an electric resistor and the like, facing and proximate to the at least one component at least partially made of a shape memory alloy for the subjection thereof to a thermal stress of the type of heating.
It is specified that the shape memory alloys of prevalent interest for the application of the present invention are those of the type preferably selected from 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.
Advantageously the present invention provides an electric lock 1 that is less prone to failures, in particular being adapted to withstand any overvoltages owing to atmospheric discharges and/or to switching maneuvers on the power supply electricity line
In fact the actuator 5 does not comprise delicate electrical components (such as electrical windings) but only components that are simple and robust and adapted to withstand overvoltages without undergoing failures.
Conveniently the electric lock 1 is constituted by a low number of simple components. This simplifies the operations of assembly and installation, thus reducing the associated labor costs.
Effectively the electric lock 1 can offer reduced encumbrances due to the fact that all the voluminous components typical of the known art (electromagnets in the first place) have been eliminated.
Positively the electric lock 1 can have an aesthetic appearance that is essential and of minimal visual impact. This is due to the reduction of its encumbrances, which makes it possible to form the box-like body 2 according to shapes and with sizes that it is impossible to adopt with conventional electric locks.
Where the technical features mentioned in any claim are followed by reference numerals and/or signs, those reference numerals and/or signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference numerals and/or signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference numerals and/or signs.

Claims

An electric lock of the type comprising a box-like body (2), provided with at least one front opening (3) for the passage of at least one spring latch (4) which is movable from a retracted configuration to a protruding configuration, comprising at least one electrical actuator (5), which is functionally associated with said spring latch (4) for the movement thereof, said actuator (5) being provided with at least one component at least partially made of a material of the type of a shape memory alloy, said component being deformable, following an external stress of type selected from the passage of an electric current through it and exposure to a heat source, from a first inactive configuration, in which said spring latch (4) is arranged protruding from said box-like body (2), to a second configuration of actuation, in which said spring latch (4) is arranged retracted into said box-like body (2), wherein said box-like body (2) comprises at least one front window (6) for the passage of at least one rearming piston (7), said piston (7) being coupled to a corresponding bracket (8) for supporting said at least one spring latch (4), with the interposition of respective elastic elements (9), said actuator (5) being constituted by said rearming piston (7), by said elastic elements (9) and by at least one locking pin (10) at least partially made of a shape memory alloy, said at least one locking pin (10), when the lock (1) is in the closed position, corresponding to said at least one spring latch (4) in the configuration protruding from the box-like body (2) and said at least one rearming piston (7) completely retracted within said box-like body (2) and said elastic elements (9) compressed against the corresponding bracket (8), being, following an external stress of the type selected from the passage of an electric current through it and exposure to a heat source, deformable from the first inactive configuration, corresponding to its engagement on said bracket (8) for the locking thereof by friction/interference, to a configuration of actuation, corresponding to its removal from the bracket (8) with consequent freeing thereof and corresponding retrograde sliding by the action of said elastic elements (9) and consequent reentry of said spring latch (4) within said box-like body (2).
The electric lock according to claim 1, characterized in that said electrical actuator (5) is provided with respective terminals (20) for connection to a low/ultralow voltage electric power supply circuit.
The electric lock according to one or more of the preceding claims, characterized in that said actuator (5) comprises at least one heater of the type of an electric resistor and the like, facing and proximate to the at least one component at least partially made of a shape memory alloy for the subjection thereof to a thermal stress of the type of heating.
The electric lock according to one or more of the preceding claims, characterized in that said shape memory alloy is of the type preferably selected from 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.