EP1030010A2

EP1030010A2 - Electromechanical actuator

Info

Publication number: EP1030010A2
Application number: EP00301338A
Authority: EP
Inventors: Oiva Hurskainen
Original assignee: Abloy Oy
Current assignee: Abloy Oy
Priority date: 1999-02-19
Filing date: 2000-02-21
Publication date: 2000-08-23
Also published as: EP1030010A3

Abstract

An electromechanical actuator comprising a body element (1) and an elongate interaction means (3, 3', 3''), one of which is provided with electromagnetic means (2) and the other of which comprises ferromagnetic material or a permanent magnet. The body element and interaction means are arranged with respect to each other so that a rotational motion may be imparted to the interaction means (3, 3', 3'') by means of a created magnetic field. The interaction means (3, 3', 3'') is rotatable between two rotational positions by altering the polarity of the electromagnetic means. When in one rotational position, the interaction means (3, 3', 3'') is displaceable in a direction of its rotation axis, by the application of an external force. The interaction means is arranged to co-operate with the body element (1) in a manner such that they together define the freedom of operation of the interaction means (3, 3', 3'') in the axial direction.

Description

This invention relates to an electromechanical actuator according to the preamble of claim 1. The invention also relates to a locking device, e.g. a cylinder lock arrangement, incorporating such an electromechanical actuator.
In publication FI 1000907 there is shown an electromechanical cylinder lock arrangement comprising a body part of a lock and, housed within the body part, a lock cylinder which, in an open position of the lock mechanism, is turnable relative to the body part, and blocking means functionally dependent on an electronic code and which, in the locking position, impedes turning of the lock cylinder relative to the body part independently of the lock mechanism. The blocking means comprises an electromechanically turnable blocking member which cooperates with a guiding groove formed in the lock cylinder or in a turnable member and continuously turns therewith so that in its locking turning position it impedes the free turning movement of the lock cylinder relative to the body part. In this known arrangement the blocking member is turnable and thus it always needs to be arranged in a guiding groove and this in turn results in more space consuming arrangement.
An arrangement for blocking or preventing the rotation of a locking apparatus is also shown in DE-A-4029208. However, this known apparatus has a very complicated structure with numerous components which renders its reliability to be suspect.
In the field of locking and precision mechanisms there is a demand for relatively small sized actuators which can be simply and reliably constructed and with which it is possible to control an operation. The electric power requirement for operating the actuator should be modest, so that a simple, safe and cost-effective power source arrangement may be used with the actuator.
It is an object of the invention to provide such an actuator. It is also an object of the invention to provide an actuator which is more advanced, reliable and less space consuming than those of the prior art.
According to one aspect of the present invention there is provided an electromechanical actuator as claimed in the ensuing claim 1.
According to another aspect of the present invention there is provided an electromechanical actuator which comprises a body element and elongate interaction means, at least one of which is provided with electromagnetic means and the other of which comprises ferromagnetic material or a permanent magnet, the body element and interaction means being arranged with respect to each other so that a rotational motion may be imparted to the interaction means by means of a created magnetic field, characterised in that said interaction means is turnable between two rotary positions by means of altering the polarity of the electromagnetic means so that at one rotary position the interaction means is displaceable by virtue of an external force in a direction of its turning axis. The interaction means is arranged to receive the external force by arranging it to be received in the body element so that one of its ends is free at least to such an extent that it is capable of receiving the external force. The interaction means is arranged to co-operate with the body element in a manner that they together define the freedom of operation of the interaction means. According to a preferred embodiment of the invention, the other end of the interaction means is arranged to cooperate with guiding surfaces of the body element in a manner that they together define the freedom of operation of the interaction means in an axial direction.
In the body element there is favourably limit stop means for restricting the freedom of rotation of the interaction means and hence for defining its rotary (limit) positions. In this manner the consumption of electric power can be minimized because only electric pulses activating the rotational movement of the interaction means and the supply of current for a short period is required in order to move the interaction means from one to the other limit position and to maintain it at that limit position. The solution is also reliable. In practice the freedom of rotation of the interaction means is preferably from about 60° to 90°.
In order to control the axial movement of the interaction means, the guiding surfaces of the body element may comprise a chamber of reduced cross-section into which a portion of the interaction means is received when turned into one of its rotary limit positions. The periphery of the chamber may comprise a step-wise counter surface. Additionally the chamber may be provided with a release spring for the interaction means. Alternatively the periphery of the chamber may include bevelled guiding surfaces, which are arranged to guide the axial return movement of the interaction means.
In order to prevent the interaction means from being moved out of a rotary limit position by, for example, external magnetic fields or other disturbances, such as vibrations, the body element may be provided with a permanent magnet. Thus the interaction means can be retained in a respective rotary position brought about by the electromagnetic means without supplying power constantly to the electromagnetic means.
According to a further aspect of the present invention there is provided a locking device incorporating an actuator according to said one aspect of the present invention.
Embodiments of the invention will now be described, by way of example only, with particular reference to the accompanying drawings, in which:
Fig. 1 shows schematically in longitudinal section one embodiment of an actuator according to the invention in which an interaction means of the actuator is in an initial outer position;
Fig. 2 is a sectional view taken on the line II-II of Fig. 1;
Fig. 3 shows the embodiment of Fig. 1 with the interaction means pressed into an inner position;
Fig. 4 shows schematically a second embodiment of an actuator according to the invention with its interaction means in an initial position;
Fig. 5 shows the embodiment of Fig. 4 with the interaction means pressed into an inner position;
Fig. 6 schematically shows inner parts of a third embodiment of an actuator according to the invention;
Fig. 7 is a sectional view taken on the line VII-VII of Fig. 6;
Fig. 8 shows schematically a fourth embodiment of an actuator according to the invention with the interaction means in a pressed in condition;
Fig. 9 is a sectional view taken on the line IX-IX of Fig. 8;
Fig. 10 is an axial sectional view of a cylinder lock arrangement incorporating a fifth embodiment of an actuator according to the invention, the locking members of the lock arrangement being shown in initial positions corresponding to the insertion position of a key;
Fig. 11 is a sectional view taken on the line XI-XI of Fig. 10;
Fig. 12 is an axial sectional view of the embodiment of Fig. 10, taken at the position of the locking bar of the lock, after the key of the lock has been turned about 45° but without the correct electric code having been supplied;
Fig. 13 is an enlarged sectional view illustrating part of the lock shown in Fig. 12; and
Fig. 14 is an axial sectional view of the embodiment of Fig. 10, taken at the position of the locking bar of the lock, after the key of the lock has been turned about 45° but with the correct electric code having been supplied.
Figs. 1 to 3 show an actuator according to the invention comprising a body element 1, in which electromagnetic means 2 is mounted, and, preferably elongate, interaction means 3 which is received within a cylindrical bore of the body element. The body element 1 also has an inner chamber 4 which opens into the bottom of the cylindrical bore. This chamber 4 co-operates with the innermost end 3a of the interaction means as will be described in more detail below.
The interaction means 3 is made of ferromagnetic material and interacts with the electromagnetic means 2 so that, when electrical current is passed through the latter in one direction, the interaction means 3 is magnetically turned in a first rotary direction. If the electrical current passing through the electromagnetic means 2 is reversed (i.e. so as to reverse the polarity of the electromagnetic means 2), the interaction means 3 turns in an opposite second rotary direction. As shown schematically in Fig. 1, a controlling means 7 is arranged to control the operation of the electromagnetic means 2. The controlling means 7 comprises a logic circuit 8 and a switch 9 which operates to open and close the logic circuit 8. Depending on the application, the logic circuit 8 makes decisions based on changes in external operating circumstances or conditions. Additionally the controlling means 7 comprises means (not shown) known as such in the art for altering the direction of the current.
The actuator requires power to operate. A power source (not shown) may, again depending on the application, be located in the body element 1, be in other apparatus associated with and in the vicinity of the actuator, or be fed from an external device when required, for example, in a lock application, from a key for the lock together with an electronic code whenever the actuator is required.
In order to limit the rotational or turning movement of the interaction means, the body element 1 is provided with angularly spaced apart limit stops 1a and 1b for limiting the rotary movement between the extreme limit positions to, for example, from 60° to 90°. Additionally, the body element 1 is provided with a permanent magnet 6 in the vicinity of the limit stop 1a for retaining the interaction means in its rotational limit positions effected by the electromagnetic means 2. In this manner it is possible to ensure an undisturbed operation of the interaction means.
The interaction means 3a can be moved axially between an outer position (see Figs. 1 and 2) and an inner position (see Fig. 3). However, the inner end 3a of the interaction means 3 and the chamber 4 are so designed that axial displacement of the interaction means from its outer position to its inner position, by the application of an external force 10 can only be accomplished when the interaction means is in one of its rotational limit positions. Thus when the interaction means 3 is in its axially outer position and is in the rotational limit position shown in Figs. 1 and 2, the interaction means 3 cannot be pressed into the body element 1. When the interaction means 3 is in its axially inner position, it may be arranged to allow or provide a desired action depending on the particular application.
ln the embodiment of the actuator shown in Figs. 1 - 3, the end 3a of the interaction means 3 has a reduced cross-section which can only be received in the similarly shaped chamber 4 when the interaction means 3 is turned into its rotational limit position shown in Fig. 3. A spring 5 is positioned in the chamber 4, which is compressed when the interaction means 3 is in its axially inner position and provides a spring force for returning the interaction means 3 to its axially outermost position after removal of the external force 10. When back in its axially outer position, the interaction means 3 can be turned back by means of the electromagnetic means 2 to its initial limit position shown in Figs. 1 and 2.
Figs. 4 and 5 and Figs. 6 and 7 illustrate two different embodiments of actuator according to the invention. The actuator shown in Figs. 4 and 5 differs from the actuator of Figs. 1 - 3 in respect of the end 3a of the interaction means 3 and in respect of the chamber 4. In particular, the actuator of Figs. 4 and 5 has an interaction means 3' with a tapering, or wedge-shaped inner end portion 3a'. The chamber 4' has a similar shape with V-shaped guide surfaces. Because of the V-shaped guide surfaces, axial return motion of the interaction means 3' from its innermost position shown in Fig. 5 back to its outermost position shown in Fig. 4, may be accomplished by forced control without the need for a spring. In particular, use is made of the rotational motion of the interaction means 3'.
In the embodiment of actuator shown in Figs. 6 and 7, the chamber 4'' has bevelled guide surfaces for achieving return movement of the interaction means in a manner similar to that of the actuator shown in Figs. 4 and 5. In this case the interaction means 3'' has a bevelled inner end portion 3a'' which is rounded or chamfered at its outermost end so that the bevelled surfaces of the chamber 4'' may accomplish the axial return of the interaction means on turning the latter from limit position A to limit position B (see Fig. 7) also, in this case, without the use of a spring.
Applications of the invention do not require a large power consumption. For the applications described, it is possible to use a 2.5 volt power supply with a capacitor of 50 - 100 µF capacitance loaded to provide a short, for example 3 ms, relatively strong pulse of electric current. After the pulse the current may be from 3-10 mA. The total duration may be below 20 ms.
In the embodiments described above the interaction means 3, in its outer position, extends clearly outside the body element 1. However this is not essential for the operation of the actuator, it being sufficient for the end of the interaction means to be free. Thus the interaction means may, in its outermost position, be flush with the respective outer surface of the body element. If required, the outer end of the interaction means, in the outermost position of the latter, may even be inset from the outer surface of the body element. In this case, the outer end of the interaction means should be capable of being pressed further inwards by the application of an external force.
Figs. 8 and 9 show another embodiment of an actuator according to the invention which is actuable to allow or to prevent rotational movement of a shaft 11 or the like of a lock cylinder of a lock arrangement (not shown). The interaction means projects from one end of the body element 1 and is movable between a first position (shown in full lines in Fig. 8) and a second position (shown in chain lines in Fig. 8) in which the projecting end is received in a cavity in the shaft 11 to prevent turning of the latter when the interaction means is turned into its rotary end position shown in chain lines in Fig. 9. In its other rotary end position (shown in full lines in Fig. 9), the curved surfaces of the shaft cavity and the curved surfaces at the end of the interaction means cooperate with each other, when the shaft 11 is turned, to retract the interaction means. Since the interaction means serves simultaneously also as blocking means, this leads to a more simple and reliable arrangement. In this embodiment, the chamber 4''' for co-operating with the interaction means 3''' is arranged to receive an intermediate diametrically extending section of the interaction means when the interaction means is in one of its rotary limit positions. As shown, both ends of the interaction means 3''' are kept free for interacting with external forces if desired. It is also possible to provide the body element 1 with a backing plate 1' or the like (as shown by dashed lines in Fig. 8) if it is required to close the end of the actuator. The shaft 11 or the like is shown merely for sake of understanding the invention. By way of example, the shaft 11 may comprise a shaft for transmitting turning movement of a key to a lock barrel (not shown). Alternatively, for example, the shaft may comprise a locking disk of a cylinder lock for which the present invention provides a particularly convenient solution due to its simple construction and small size.
Another application of an actuator according to the invention used in an electromechanical cylinder lock is shown in Figs. 10 - 14. The lock has a lock body 41 which includes, at the key insertion end of a key channel, an element 21 which turns continuously with the key. The element 21 defines the profile of keys compatible with the lock and also serves as a deterrent to drilling of the lock. Located radially outside the element 21 there is a guiding disc 22, which is non-turnably supported against a lock cylinder 42 and which supports and guides the locking disc 49'' which, thus, remains between a control unit 40'' and the guiding disc 22.
In order to connect the locking disc 49'' to the turning movement of the key, the control unit 40'' includes an actuating member or interaction means 25 which is controlled by an electromagnet 18'' included in electric operating means 17''. At the position of the interaction means 25 there is a coupling recess 24 in the control unit 40'' which is provided with a bevelled guiding surface 24a. The interaction means 25 can be turned between two rotary end positions by changing the polarity of the electromagnet 18'' so that in one rotary end position the interaction means 25 can be pressed against the force of a spring 26 entirely inside the control unit 40'' as is apparent from Fig. 13. For this purpose an inner end 25a of the interaction means 25 is suitably designed to be narrower. In addition the body unit of the electromagnet 18'' is provided with limiting members or limit stops (cf. limit stops 1a and 1b of Figs. 1-3) which determine the angular turning range of the interaction means 25, which is preferably 90° or less. Furthermore, the arrangement advantageously includes a permanent magnet 28, which keeps the interaction means 25 in one of its rotary end positions corresponding to the initial position and thereby ensures that the interaction means cannot be affected by means of external magnetic fields or other disturbances, for instance shakes or vibrations.
The locking disc 49'' for its part includes a throughgoing hole 49d'' which encloses a coupling member 23 which can be pressed, against the force of a spring 29, so that it extends into a recess 22a in the guiding disc 22. In this position of the coupling member 23 the locking disc 49'' cannot be turned (cf. Figs. 12 and 13). As is apparent from Fig. 11, in the initial position the coupling member 23 and the recess 22a are located at a turning angle of about 45° from the coupling recess 24 and the interaction means 25.
The operation of the embodiment of Figs. 10 -14 is as follows. In the initial position of the mechanism according to Figs. 10 and 11, in which the key is inserted into the key channel of the lock (for clarity the key is not shown in these figures), the interaction means 25, urged by the spring 26, extends beyond the coupling recess 24 against the locking disc 49''. Initially when the key is turned in the lock, the locking disc 49'' remains at its initial position, in which the coupling member 23 extends into the recess 22a in the guiding disc 22 pressed by the control unit 40'' (this position is shown in Fig. 13). After turning of the key about 45°, the coupling member 23 is located at the position of the coupling recess 24 and the interaction means 25. In the absence of a correct electric code the turning position of the interaction means 25 is not changed. Hence, the interaction means 25 prevents movement of the coupling member 23 into the coupling recess 24 and the locking disc 49'' remains together with the guiding disc 22 in its position (cf. Figs. 12 and 13) and the lock mechanism cannot be opened.
Fig. 14 shows the operation when a correct electric code is fed into the lock. As a result of identifying the code a control command is provided which changes the polarity of the electromagnet 18''. This results in the interaction means 25 being turned through 90° so that its inner end 25a is pressed by the coupling member 23, urged by the spring 29, against the force of the spring 26 into a position allowing the coupling member 23 to enter the coupling recess 24. At the same time the coupling member 23 is released from the recess 22a in the guiding disc 22. As a consequence, when the key is turned further, the locking disk 9'' turns with it so that its peripheral notch (not shown) is located at the position of the locking bar 45 (not shown) thereby allowing for its part opening of the lock mechanism.
In the lock described, the return of the locking disc 49'' does not require a separate protrusion to be arranged on the control unit 40'', but the locking disc 49'' turns under the influence of the coupling recess 24 and the coupling member 23 back to a position determined by the guiding surface 42a in the lock cylinder in which the coupling recess and coupling member are at the position of the recess 22a in the guiding disc 22. In this case, when the key is turned further, the coupling member 23 moves into the recess 22a against the force of its spring 29 urged by the guiding surface 24a in the coupling recess 24 (cf. Fig. 13) and prevents again turning of the locking disc 49'' when the key is turned in the opening direction of the locking mechanism. At the same time the spring 26 urges the interaction means 25 out against the locking disc 49'' and the interaction means 25 is turned back into the initial position according to Fig. 10 due to the changed polarity of the electromagnet 18''.
The operation of the interaction means 25 does not necessarily need a separate spring 26 since a corresponding operation can be accomplished through suitable design of the end 25a and of the counter surfaces in the body part cooperating therewith.
The interaction means 3 or body part may be made of ferromagnetic material or may comprise a permanent magnet. If the limit stop means 1a and 1b are made of ferromagnetic material, for example steel, a permanent magnet 6 is not required. An alternative solution for providing the rotary motion is to position a coil inside the interaction means and to provide a permanent magnet for the body element. There should be magnetic coupling between the body part and the interaction means to allow relative turning between the two parts when the electromagnetic means is energised. Instead of reversing the polarity of the electromagnetic means, it would be possible to bias, e.g. spring bias, the interaction means into one rotary end position with no power supplied to the electromagnetic means and to move the interaction means to its other rotary end position by energising the electromagnetic means to create a magnetic field to turn the interaction means against the (spring) bias. However this solution requires an increased power consumption to retain the interaction means for a relatively long period of time, e.g. several seconds, in the rotary end position allowing the axial movement against the (spring) biasing force. The interaction means may be in a form of a circular pin arranged in a bore or the like in the body element.
The invention is not restricted to the embodiments shown, but several modifications are feasible within the scope of the attached claims.

Claims

An electromechanical actuator comprising a body element (1) and a, preferably elongate, interaction means (3, 3', 3'') turnable, relative to the body element (1), about a turning axis between angularly spaced apart first and second rotary positions, one of said body element and said interaction means being provided with electromagnetic means (2) which, when energised, magnetically couples the body element and the interaction means and controls the turning of the interaction means (3, 3', 3'') relative to the body element (1) between said first and second rotary positions, characterised in that the interaction means and the body element are so arranged that the interaction means is displaceable in a direction of said turning axis by the application of an external force to the interaction means when the latter is in its first rotary position, and in that the interaction means (3, 3', 3'') and the body element (1) together define the freedom of movement of the interaction means relative to the body element parallel to said turning axis.
An actuator according to claim 1, characterised in that the other of said body element and said interaction means comprises ferromagnetic material or comprises a permanent magnet.
An actuator according to claim 1 or 2, characterised in that means are provided for switching the polarity of the electromagnetic means to turn the interaction means between its first and second rotary positions.
An actuator according to any one of claims 1 to 3, characterised in that said interaction means and said body element cooperate with each other to allow or prevent relative axial movement therebetween parallel to said turning axis in dependence on their rotary positions relative to each other.
An actuator according to any one of the preceding claims, characterised in that the body element (1) is provided with stop means (1a, 1b) for preventing turning of the interaction means (3, 3', 3'') past each of its first and second rotary positions.
An actuator according to any one of the preceding claims, characterised in that in the freedom of turning of the interaction means (3, 3', 3'') between its first and second rotary positions is from 60° to 90°.
An actuator according to any one of the preceding claims, characterised in that the body element (1) has a cavity in which the interaction means is received, in that the cavity includes a chanter (4, 4', 4''), and in that the chamber and a portion of the interaction means are so shaped that the interaction means can be axially displaced so that the end portion is received in said chamber when the interaction means is in said first rotary position but not when the interaction means is in its second rotary position.
An actuator according to claim 7, characterised in that the periphery of the chanter (4) comprise a step-wise counter surface and that the chanter (4) is provided with a release spring (5) for the interaction means (3, 3', 3'').
An actuator according to claim 7, characterised in that the periphery of the chamber (4', 4'') includes bevelled guiding surfaces, which are arranged to guide the axial return movement of the interaction means (3', 3'') on turning of the latter.
An actuator according to any one of the preceding claims, characterised in that the body element (1) is provided with a permanent magnet (6) to maintain the interaction means (3, 3', 3'') at a respective rotary position brought about by the electromagnetic means (2).
An actuator according to any one of the preceding claims, characterised in that one end of the interaction means is intended to have said external force applied thereto and the other end of the interaction means is arranged to co-operate with guiding surfaces inside the body element (1) in a manner such that they together define the said freedom of movement of the interaction means relative to the body element parallel to said turning axis.
An actuator according to claim 1, characterised in that the interaction means is mounted in the body element so that one of its ends is free to receive said external force and is arranged to co-operate with shaft means (11) of a locking device for allowing or preventing rotational movement of the shaft means.
A locking device incorporating an actuator as claimed in any on of the preceding claims.