WO2013080231A1

WO2013080231A1 - Electric lock

Info

Publication number: WO2013080231A1
Application number: PCT/IT2011/000393
Authority: WO
Inventors: Fausto Fustini
Original assignee: Cisa S.P.A.
Priority date: 2011-11-30
Filing date: 2011-11-30
Publication date: 2013-06-06
Also published as: ES2673222T3; EP2785938B1; EP2785938A1

Abstract

An electric lock (1) 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. 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) being provided with at least one component at least partially made of a material of the type of a shape memory alloy. The component 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 (4) is arranged protruding from the box-like body (2), to a second configuration of actuation, in which the spring latch (4) is arranged retracted into the box-like body (2).

Description

ELECTRIC LOCK

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.

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, characterized in that it comprises 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.

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 partially sectional schematic side view of a third possible embodiment of an electric lock according to the invention;

Figure 4 is a partially sectional schematic side view of a fourth possible embodiment of an electric lock according to the invention;

Figure 5 is a partially sectional schematic side view of a fifth possible embodiment of an electric lock according to the invention;

Figure 6 is a partially sectional schematic side view of a sixth possible embodiment of an electric lock according to the invention;

Figure 7 is a schematic view of the components of a possible embodiment of an electric lock according to the invention;

Figure 8 is a schematic view of the components of a further embodiment of an electric lock according to the invention;

Figure 9 is a schematic view of the components of another 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 4, 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 4, can engage a tooth 12 of an oscillating lever 13 which is adapted to lock a sleeve 15 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.

According to a further particularly efficient embodiment of simple and practical implementation, the at least one electrical actuator 5 is constituted by an element 14 at least partially made 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 spring latch 4 and a bracket 8 for the anchoring and movement of the spring latch 4 within the box-like body 2.

Following an external stress of the type preferably selected from the passage of an electric current through it and exposure to a heat source, the element 14 becomes deformable from an inactive configuration in which it has a greater length, and in which the spring latch 4 is arranged protruding from the box-like body 2, to a second configuration of actuation in which it has a shorter length, and in which the spring latch 4 is arranged retracted into the box-like body.

In particular it is specified that the element 14 made at least partially of a material of the type of a shape memory alloy is preferably shaped like a helical spring with axial action. The contiguous coils of such a spring will be mutually distant in the first inactive configuration in which the element 14 is not subjected to the external stresses, and will face each other and be proximate in the second configuration of actuation in which the element 14 is subjected to the external stresses.

It can thus be concluded that the spring latch 4 undergoes a retraction into the box-like body 2 when the element 14 is stimulated and thus contracts.

The embodiment described can be actuated in different ways. Figures 2 and 5 show two possible applications relating to this embodiment.

With particular reference to a further possible embodiment of safe, simple and practical application, elastic means 15 are interposed between the face directed toward the inside of the box-like body 2 of the spring latch 4 and its bracket 8 for anchoring and movement within the box-like body 2.

The at least one electrical actuator 5, in such case, will comprise at least one unit 16, functionally associated with the spring latch 4, which is movable along a preset stroke by the action of a pusher 17 at least partially made of a material of the type of a shape memory alloy.

The stroke of the unit 16 will in such case be defined between two limit arrangements, a first arrangement corresponding to the spring latch 4 protruding from the box-like body 2 by the action of the elastic means 15, a second arrangement corresponding to the spring latch 4 retracted within the box-like body 2 in contrast to the elastic means 15 (by the action of the pusher 17).

It should be noted that such an embodiment can effectively be implemented by adopting a movable unit 16 constituted by a lever pivoted on the box-like body 2. The lever in such case will be provided with one arm 18 associated with the spring latch 4 and the opposite arm 19 associated with the pusher 17.

When the pusher 17 (at least partially made from shape memory alloys and/or materials having similar physical properties) is not stimulated (i. e. not crossed by an electric current and not exposed to a heat source) its length is minimal and therefore does not act on the arm 19 of the lever 16. The spring latch 4 thus continues to protrude from the box-like body 2 by the action of the elastic means 15.

At the moment, however, when the pusher 17 is stimulated (i.e. crossed by an electric current and/or exposed to a heat source) its length will undergo an increase and thus will act on the arm 19 of the lever 16 causing a rotation thereof which will lead to the retraction of the spring latch 4 until it is completely retracted within the box-like body 2.

The solution described is substantially shown in some possible practical applications in Figures 3 and 6.

A possible practical implementation of the embodiment comprising the movable unit 16 is one in which the unit is provided by means of a skid which is slideable along a guide defined on the box-like body 2.

In such case a first portion of the skid will be associated with the spring latch 4 and a second portion thereof will be associated with the pusher 17.

The variations in length of the pusher 17, owing to the physical properties of the material of the type of shape memory alloys that constitute it at least partially, owing to the external stresses described previously, will cause shifts of the skid with consequent entrainment of the spring latch 4 (in contrast to the thrust of the elastic means 15). 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.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

In the embodiments illustrated, individual characteristics shown in relation to specific examples may in reality be replaced by other, different characteristics, existing in other embodiments.

In practice, the materials employed, as well as the dimensions, may be any according to requirements and to the state of the art.

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

1. 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, characterized in that it comprises 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).

2. The electric lock according to claim 1, characterized in that 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).

3. The electric lock according to claim 1, characterized in that said at least one electrical actuator (5) is constituted by an element (14) made at least partially of a material of the type of a shape memory alloy which is interposed between the face directed toward the inside of said box-like body (2) of said spring latch (4) and a bracket (8) for the anchoring and movement of said spring latch (4) within said box-like body (2), said element (14) being, following an external stress of type selected from the passage of an electric current through it and exposure to a heat source, deformable from the first inactive configuration, deformable from an inactive configuration of greater length, in which said spring latch (4) is arranged protruding from said box-like body (2), to a second configuration of actuation of shorter length, in which said spring latch (4) is arranged retracted into said box-like body (2).

4. The electric lock according to claim 3, characterized in that said element (14) made at least partially of a material of the type of a shape memory alloy is shaped like a helical spring with axial action, the contiguous coils of said spring being mutually distant in said first inactive configuration in which said element (14) is not subjected to said external stresses, and being facing and proximate in the second configuration of actuation in which said element (14) is subjected to said external stresses.

5. The electric lock according to claim 1, characterized in that elastic means (15) are interposed between the face directed to the inside of said box-like body (2) of said spring latch (4) and a bracket (8) for the anchoring and movement of said spring latch (4) within said box-like body (2); said at least one electrical actuator (5) comprises at least one unit (16), functionally associated with said spring latch (4), which is movable along a preset stroke by the action of a pusher (17) at least partially made of a material of the type of a shape memory alloy, said stroke being defined between two limit positions, a first position corresponding to said spring latch (4) protruding from said box-like body (2) by the action of said elastic means (15), a second position corresponding to said spring latch (4) retracted within said box-like body (2) in contrast to said elastic means (15).

6. The electric lock according to claim 5, characterized in that said movable unit (16) is a lever pivoted on said box-like body (2), said lever having one arm (18) associated with said spring latch (4) and an opposite arm (19) associated with said pusher (17).

7. The electric lock according to claim 5, characterized in that said movable unit (16) is a skid which is slideable along a guide defined on said box-like body (2), said skid having a first portion associated with said spring latch (4) and a second portion associated with said pusher (17).

8. The electric lock according to one or more of the preceding claims, characterized in that said electrical actuator (5) is provided with respective terminals (20) for connection to a low/ultralow voltage electric power supply circuit.

9. 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.

10. 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.