Actuator comprising electro permanent magnet and method

Abstract

Actuator (10) comprising a base section (14,14a,14b); a permanent magnet (18,18a,18b); an electro permanent magnet (20, 20a, 20b); a coil (22, 22a, 22b) located around the electro permanent magnet (20, 20a, 20b); a power controller (24, 24a, 24b); and a movable member (28) comprising at least one magnetic target section (36), the movable member (28) being arranged to move to a first position (12) relative to the base section (14,14a,14b), when the electro permanent magnet (20, 20a, 20b) adopts a first polarity, and arranged to move to a second position (46) relative to the base section (14,14a,14b) due to a magnetic field generated by the permanent magnet (18,18a,18b) and the electro permanent magnet (20, 20a, 20b) in combination and acting on the magnetic target section (36), when the electro permanent magnet (20, 20a, 20b) adopts a second polarity. A lock device (50), a handle device (86) and a method are also provided.

Claims

1. Actuator comprising: at least one base section; at least one permanent magnet arranged in the base section; at least one electro permanent magnet arranged in the base section, the at least one electro permanent magnet being configured to switch a polarity between a first polarity and a second polarity when being subjected to a magnetic field and configured to maintain the polarity when the magnetic field is removed; a coil located around the electro permanent magnet; a power controller configured to apply a current pulse to the coil to generate the magnetic field for changing the polarization of the electro permanent magnet; and a movable member comprising at least one magnetic target section, the movable member being arranged to move to a first position relative to the base section, when the electro permanent magnet adopts the first polarity, and arranged to move to a second position relative to the base section due to a magnetic field generated by the permanent magnet and the electro permanent magnet in combination and acting on the magnetic target section, when the electro permanent magnet adopts the second polarity; wherein each of the at least one electro permanent magnet is hollow and the movable member is arranged to move within each of the at least one electro permanent magnet.

2. The actuator according to claim 1, further comprising at least one resetting element configured to move the movable member to the first position when the electro permanent magnet adopts the first polarity.

3. The actuator according to claim 2, wherein the resetting element an elastic element and wherein the actuator is configured such that the magnetic field, generated by the permanent magnet and the electro permanent magnet in combination and acting on the magnetic target section when the electro permanent magnet adopts the second polarity, moves the movable member to the second position and deforms the elastic element.

4. The actuator according to any claim 1, wherein: the at least one base section is constituted by a first base section and a second base section; the at least one permanent magnet is constituted by a first permanent magnet and a second permanent magnet; the at least one electro permanent magnet is constituted by a first electro permanent magnet arranged in the first base section and a second electro permanent magnet arranged in the second base section; and the movable member is arranged to move to the first position relative to the first base section and the second base section, when the first electro permanent magnet adopts the first polarity, and arranged to move to the second position relative to the first base section and the second base section due to a magnetic field generated by the first permanent magnet and the first electro permanent magnet in combination and acting on the magnetic target section, when the first electro permanent magnet adopts the second polarity.

5. The actuator according to claim 4, wherein the movable member is arranged to move to the first position relative to the first base section and the second base section due to a magnetic field generated by the second permanent magnet end the second electro permanent magnet in combination and acting on the magnetic target section.

6. The actuator according to claim 1, further comprising a first mechanical stop defining the first position of the movable member relative to the base section.

7. The actuator according to claim 1, further comprising a second mechanical stop defining the second position of the movable member relative to the base section.

8. The actuator according to claim 1, wherein the movable member is arranged to move substantially linearly relative to the base section between the first position and the second position.

9. The actuator according to claim 1, wherein a magnetic field outside the base section is substantially neutral when the electro permanent magnet adopts the first polarity.

10. The actuator according to claim 1, wherein the permanent magnet and the electro permanent magnet are polarized in the same direction when the electro permanent magnet adopts the second polarity.

11. Lock device comprising an actuator according to claim 1.

12. The lock device according to claim 11, wherein the lock device is constituted by a lock cylinder comprising a stationary structure and a cylinder core rotatably accommodated in the stationary structure, wherein the first position of the movable member constitutes a disconnecting position in which the cylinder core is allowed to rotate relative to the stationary structure, and wherein the second position of the movable member constitutes an interconnecting position in which the movable member engages both the cylinder core and the stationary structure such that the cylinder core is prevented from rotating relative to the stationary structure.

13. The lock device according to claim 11, wherein the lock device is constituted by a lock case comprising a follower unit having a hub and a coupling device, wherein coupling device is movable under control of the actuator between an engaging position where two parts of the hub are engaged and a disengaging position where the two parts of the hub are disengaged.

14. Handle device for operating doors, windows and the like, the handle device comprising an actuator according to claim 1, a first element rotatable about an axis, a second element rotatable about the axis, a coupling device movable under control of the actuator between an engaging position where the first element and the second element are engaged and a disengaging position where the first element and the second element are disengaged.

15. Method for operating an actuator comprising at least one base section, at least one permanent magnet arranged in the base section, at least one electro permanent magnet arranged in the base section, and a movable member comprising at least one magnetic target section, wherein each of the at least one electro permanent magnet is hollow and the movable member is arranged to move within each of the at least one electro permanent magnet, the method comprising: providing the electro permanent magnet with a first polarity such that a magnetic field outside the base section is substantially neutral; switching the polarity of the electro permanent magnet from the first polarity to a second polarity such that the permanent magnet and the electro permanent magnet combine to generate a magnetic field acting on the magnetic target section such that the movable member moves within the electro permanent magnet from a first position relative to the base section to a second position relative to the base section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details, advantages and aspects of the present disclosure will become apparent from the following embodiments taken in conjunction with the drawings, wherein:

(2) FIG. 1a: schematically represents a side view of an actuator in a first position;

(3) FIG. 1b: schematically represents a side view of the actuator in FIG. 1a in a second position;

(4) FIG. 2a: schematically represents a side view of a further actuator in a first position;

(5) FIG. 2b: schematically represents a side view of the actuator in FIG. 2a in a second position;

(6) FIG. 3a: schematically represents a side view of a lock device comprising an actuator in a first position;

(7) FIG. 3b: schematically represents a side view of the lock device in FIG. 3a and the actuator in a second position;

(8) FIG. 4: schematically represents a perspective exploded view of a further lock device comprising an actuator;

(9) FIG. 5: schematically represents a side view of a handle device comprising an actuator;

(10) FIG. 6a: schematically represents a cross sectional side view of the handle device in FIG. 5 and the actuator in a first position; and

(11) FIG. 6b: schematically represents a cross sectional side view of the handle device in FIGS. 5 and 6a and the actuator in a second position.

DETAILED DESCRIPTION

(12) In the following, an actuator comprising an electro permanent magnet and a movable member arranged to move between a first position and a second position, lock devices comprising the actuator, a handle device comprising the actuator and a method for operating the actuator, will be described. The same reference numerals will be used to denote the same or similar structural features.

(13) FIG. 1a schematically represents a side view of an actuator 10. In FIG. 1a, the actuator 10 is in a first position 12. The actuator 10 comprises a base section 14. The base section 14 comprises two pole pieces 16, a permanent magnet 18 and an electro permanent magnet 20. The permanent magnet 18 and the electro permanent magnet 20 are arranged between the two pole pieces 16. As shown in FIG. 1a, the electro permanent magnet 20 is hollow. Also the permanent magnet 18 is hollow.

(14) The permanent magnet 18 may for example comprise a Neodymium alloy and the electro permanent magnet 20 may for example comprise an Alnico alloy. In FIG. 1a, the permanent magnet 18 and the electro permanent magnet 20 have opposite polarities such that a magnetic field outside the base section 14 is substantially neutral.

(15) The pole pieces 16 may for example be made of relay steel, such as Hiperco® alloy. At least the right pole piece 16 may have a smooth exterior surface to minimize air gaps.

(16) A coil 22 is wound around the permanent magnet 18 and the electro permanent magnet 20. The number of windings of the coil 22 may vary. The coil 22 may comprise copper wirings.

(17) The actuator 10 further comprises a power controller 24. The power controller 24 is in this example powered by a battery 26. The power controller 24 is configured to apply current pulses to the coil 22 such that magnetic fields are generated. The power controller 24 may comprise switches, a pulse control transistor and a flyback diode for protecting the pulse control transistor. The battery 26 may provide a high power voltage supply (e.g. maximum 60V and maximum 20 A). Alternatively, the power controller 24 may be connected to a charged capacitor optimized for the specific pulse for the electro permanent magnet 20.

(18) The actuator 10 further comprises a movable member 28. The movable member 28 of this example is arranged to move linearly along a movement axis 30. In FIG. 1a, the movable member 28 has moved in a first direction 32 along the movement axis 30 to the illustrated first position 12.

(19) In this example, the pole pieces 16, the permanent magnet 18, the electro permanent magnet 20 and thus the entire base section 14 are cylindrical. The movable member 28 is guided within the cylindrical base section 14.

(20) The movable member 28 comprises an elongated portion and a head portion 34. The head portion 34 comprises a magnetic target section 36 of a material strongly responsive to magnetic fields. The movable member 28 further comprises a first mechanical stop 38, here implemented as a collar on the elongated portion and a second mechanical stop 40, here constituted by an inclined surface on the head portion 34.

(21) The actuator 10 further comprises a resetting element 42. In this example, the resetting element 42 is constituted by an elastic element in the form of a spring connected between the base section 14 and the movable member 28 and encircling the movable member 28. The resetting element 42 pushes the movable member 28 in the first direction 32 such that the first mechanical stop 38 engages the base section 14, more specifically the left pole piece 16 of the base section 14.

(22) By applying a current pulse to the coil 22 of sufficient duration and level, a magnetic field is generated that switches the polarity of the electro permanent magnet 20 from a first polarity to a second polarity but that does not switch the polarity of the permanent magnet 18, which has a higher coercivity. The thresholds of the magnetic fields where the electro permanent magnet 20 is flipped/switches polarity and where the permanent magnet 18 is flipped, depends on the coercivity of the respective material.

(23) The applied current pulse may for example have a duration of between 30 μs to 750 μs, such as between 50 μs to 450 μs, such as between 75 μs to 300 μs, such as 100 μs to 200 μs, such as 150 μs. Several current pulses may for example be spaced 10 ms in time. The power supply voltage may for example be 10 V to 40 V, such as 20 V to 30 V.

(24) FIG. 1b schematically represents a side view of the actuator 10 in FIG. 1a. As illustrated in FIG. 1b, when the electro permanent magnet 20 has been flipped from the first polarity in FIG. 1a to the second polarity in FIG. 1b, the permanent magnet 18 and the electro permanent magnet 20 combine to generate a magnetic field outside the base section 14. This magnetic field acts on the magnetic target section 36 and pulls the movable member 28 in a second direction 44 linearly along the movement axis 30 to a second position 46. The movable member 28 moves within the electro permanent magnet 20. At the same time, the resetting element 42 is further compressed until the second mechanical stop 40 contacts the right pole piece 16 of the base section 14. The movable member 28 is maintained in the second position 46 due to the magnetic force generated by the permanent magnet 18 and the electro permanent magnet 20 in combination until the polarity of the electro permanent magnet 20 is switched again. The right surface of the right pole piece 16 is also inclined such that a tight mating is provided between the second mechanical stop 40 and the base section 14.

(25) Since electric power is supplied only for a short time when flipping the polarity of the electro permanent magnet 20, it is possible to save energy while ensuring safety and reliability. In addition, since electric power is supplied only when flipping the polarity of the electro permanent magnet 20, there is no temperature rise. This prevents heat from being generated from the actuator 10.

(26) By applying a current pulse in the coil 22 of sufficient duration and level in a reverse direction, the polarity of the electro permanent magnet 20 can be switched from the second polarity to the first polarity. As a consequence, the magnetic field outside the base section 14 is again substantially neutral and the resetting element 42 pushes the movable member 28 in the first direction 32 back to the first position 12 in FIG. 1a where the first mechanical stop 38 contacts the base section 14.

(27) FIG. 2a schematically represents a side view of a further actuator 10. Mainly differences with respect to FIGS. 1a and 113 will be described. In FIG. 2a, the actuator 10 is in a first position 12.

(28) The actuator 10 in FIG. 2a comprises a first base section 14a and a second base section 14b. The first base section 14a and the second base section 14b are fixed relative to each other. In the example in FIG. 2a, the first base section 14a and the second base section 14b are connected by means of a connecting member 48.

(29) The first base section 14a comprises two first pole pieces 16a, a first permanent magnet 18a and a first electro permanent magnet 20a and the second base section 14b comprises two second pole pieces 16b, a second permanent magnet IA and a second electro permanent magnet 20b. The first permanent magnet 18a and the first electro permanent magnet 20a are arranged between the two first pole pieces 16a and the second permanent magnet 1813 and the second electro permanent magnet 20b are arranged between the two second pole pieces 16b. In this example, each of the first base section 14a and the second base section 14b is cylindrical. As shown in FIG. 2a, each of the electro permanent magnets 20a, 20b is hollow. Also each of the permanent magnets 18a, 18g is hollow.

(30) The movable member 28 in FIG. 2a comprises a two elongated portions and a head portion 34 therebetween. Similar to FIGS. 1a and 1b, the head portion 34 comprises the magnetic target section 36.

(31) The movable member 28 in FIG. 2a comprises a first mechanical stop 40a and a second mechanical stop 40b. In this example, each of the first mechanical stop 40a and the second mechanical stop 40b is constituted by an inclined surface on the head portion 34.

(32) A first coil 22a is wound around the first permanent magnet 18a and the first electro permanent magnet 20a and a second coil 22b is wound around the second permanent magnet 18b and the second electro permanent magnet 20b. The actuator 10 of the example in FIG. 2a comprises a first power controller 24a configured to apply current pulses to the first coil 22a and a second power controller 24b configured to apply current pulses to the second coil 22b. The first power controller 24a and the second power controller 24b are powered by a common battery 26.

(33) The actuator 10 in FIG. 2a comprises a first resetting element 42a and a second resetting element 42b. In this example, each of the first resetting element 42a and the second resetting element 42b is constituted by an elastic element in the form of a spring. The first resetting element 42a is connected between the first base section 14a and the movable member 28 and the second resetting element 42b is connected between the second base section 14b and the movable member 28. The first resetting element 42a pushes the movable member 28 in the first direction 32 such that the second mechanical stop 40b engages the second base section 14, more specifically the left second pole piece 16b of the second base section 14b.

(34) In the first position 12 of FIG. 2a, the first permanent magnet 18a and the first electro permanent magnet 20a have opposite polarities such that a magnetic field outside the first base section 14a is substantially neutral. At the same time, the second permanent magnet 18b and the second electro permanent magnet 20b are polarized in the same direction such that they combine to generate a magnetic field acting on the magnetic target section 36. This magnetic field holds the movable member 28 in the first position 12 illustrated in FIG. 2a.

(35) In order to move the movable member 28 from the first position 12 in FIG. 2a, a current pulse of sufficient duration and level is applied to the first coil 22a such that a magnetic field is generated that switches the polarity of the first electro permanent magnet 20a from a first polarity to a second polarity but that does not switch the polarity of the first permanent magnet 18a, which has a higher coercivity. At the same time, a current pulse of sufficient duration and level is applied to the second coil 22b such that a magnetic field is generated that switches the polarity of the second electro permanent magnet 20b from a second polarity to a first polarity but that does not switch the polarity of the second permanent magnet 18b, which has higher coercivity.

(36) FIG. 2b schematically represents a side view of the actuator 10 in FIG. 2a. As illustrated in FIG. 2b, when the first electro permanent magnet 20a has been flipped from the first polarity in FIG. 2a to the second polarity in FIG. 2b, the first permanent magnet 18 and the first electro permanent magnet 20 combine to generate a magnetic field outside the first base section 14.

(37) At the same time, when the second electro permanent magnet 20b has been flipped from the second polarity in FIG. 2a to the first polarity in FIG. 2b, the second electro permanent magnet 20b and the second permanent magnet 18b are oppositely polarized such that a magnetic field outside the second base section 14b is substantially neutral. The magnetic field generated by the first permanent magnet 18a and the first electro permanent magnet 20a in combination acts on the magnetic target section 36 and pulls the movable member 28 in the second direction 44 linearly along the movement axis 30 to the second position 46. The movable member 28 moves within the electro permanent magnets 20a, 20b. At the same time, the first resetting element 42a is further compressed and the second resetting element 42b is slightly released until the second mechanical stop 40b contacts the right first pole piece 16a of the first base section 14a.

(38) FIG. 3a schematically represents a side view of one example of a lock device 50 comprising an actuator 10. In FIG. 3a, the actuator 10 is of the type illustrated in FIGS. 1a and 113 but the variant in FIGS. 2a and 2b, or other variants according to the present disclosure may alternatively be employed.

(39) The lock device 50 in FIG. 3a is constituted by a lock cylinder 52. The lock cylinder 52 comprises a stationary structure 54, a cylinder core 56 rotatably accommodated in the stationary structure 54 and a knob 58 connected to the cylinder core 56. In this example, the stationary structure 54 comprises a cylinder housing 60 and a tailpiece 62. A stationary radial hole 64 is provided in the cylinder housing 60 and a cylinder radial hole 66 is provided in the cylinder core 56.

(40) The cylinder core 56 is axially fixed by means of a cylinder lock pin 68 engaging a circumferential groove on the cylinder core 56. The tailpiece 62 is axially fixed by means of a tailpiece lock pin 70 engaging a circumferential groove on the tailpiece 62.

(41) The base section 14 and the movable member 28 of the actuator 10 are arranged within the cylinder core 56 and the power controller 24 and the battery 26 are arranged within the knob 58. In FIG. 3a, the movable member 28 is in the first position 12 such that the actuator 10 adopts a disconnecting position. In the disconnecting position of FIG. 3a, the cylinder core 56 is allowed to rotate relative to the stationary structure 54 since the movable member 28 is not protruding into the stationary radial hole 64.

(42) FIG. 3b schematically represents a side view of the lock device 50 in FIG. 3a. In FIG. 3b, the movable member 28 has moved from the first position 12 to the second position 46 such that the actuator 10 adopts an interconnecting position. In the interconnecting position of FIG. 3b, the movable member 28 engages both the cylinder core 56 and the stationary structure 54. The cylinder core 56 is prevented from rotating relative to the stationary structure 54 since the movable member 28 protrudes through the cylinder radial hole 66 and into the stationary radial hole 64.

(43) FIG. 4 schematically represents a perspective exploded view of a further lock device 50 comprising an actuator 10 according to the present disclosure. The lock device 50 in FIG. 4 is constituted by a lock case 72.

(44) The lock case 72 of the example in FIG. 4 comprises a forend 74, a latch bolt 76, a hub 78, a lever handle follower unit 80, a coupling device 82 and a cover plate 84. The hub 78 has a hub axis and is adapted to receive at least one lever handle pin. The hub 78 comprises an outer hub part rotatable about the hub axis and which is adapted to receive a first lever handle pin, and an intermediate hub part rotatable about the hub axis and coupled to a bolt in the lock device 50 for movement of the bolt between an outer and an inner end position. The coupling device 82 is movable under control of the actuator 10. By moving the actuator 10 to the first position 12, the coupling device 82 is moved to a coupling position, in which the intermediate hub part rotates together with the outer hub part. By moving the actuator 10 to the second position 46, the coupling device 82 is moved to a release position, in which the outer hub part rotates freely in relation to the intermediate hub part.

(45) FIG. 5 schematically represents a side view of a handle device 86 for operating doors, windows and the like, comprising an actuator (not shown) according to FIGS. 1a and 1h. The handle device 86 of this example comprises a handle grip 88, a handle neck 90, a handle escutcheon or handle plate 92 and a swivel pin or handle spindle 94 in the form of a square shank rotatable about a handle rotational axis 96.

(46) FIG. 6a schematically represents a cross sectional side view of the handle device 86 in FIG. 5. As shown in FIG. 6a, the handle device 86 of this example further comprises a cylindrical end section 98 which is firmly connected to the handle spindle 94. The cylindrical end section 98 is rotatably accommodated in a boss 100, which is in turn received in the handle neck 90.

(47) The handle device 86 of this example further comprises an activating member 102 and an engaging member 104, here implemented as a ball. The activating member 102 is movable along the handle rotational axis 96 within the cylindrical end section 98. The engaging member 104 is movable in a radial hole 106 of the cylindrical end section 98. The activating member 102 comprises a waist section 108. The activating member 102, the engaging member 104, the cylindrical end section 98 and the boss 100 form a coupling device 110.

(48) In FIG. 6a, the actuator 10, which is in a first position 12, can be seen. In the first position 12, the actuator 10 has adopted the first position 12 such that the activating member 102 has been pulled to a position where the waist section 108 of the activating member 102 is not aligned with the radial hole 106 of the cylindrical end section 98. Due to this movement of the activating member 102, the engaging member 104 is pushed out from the waist section 108 to a position where the engaging member 104 protrudes radially outwards from the cylindrical end section 98 and into the boss 100. The cylindrical end section 98 and the boss 100 are thereby simultaneously engaged by the engaging member 104. In this way, the handle grip 88 is coupled to the handle spindle 94 and can therefore be used to operate a tumbler, an espagnolette bolt or some other member or device to which the handle spindle 94 is coupled. Thus, when the actuator 10 adopts the first position 12, the coupling device 110 adopts an engaging position where a first element (the boss 100) and a second element (the cylindrical end section 98) are engaged.

(49) FIG. 6b schematically represents a cross sectional side view of the handle device 86 in FIGS. 5 and 6a. In FIG. 6b, the movable member 28 has pushed the activating member 102 to a position where the waist section 108 of the activating member 102 is aligned with the radial hole 106 of the cylindrical end section 98. As a consequence, the engaging member 104 is pushed into the waist section 108 of the activating member 102 such that the engaging member 104 does not protrude out from the cylindrical end section 98.

(50) If the handle grip 88 (see FIG. 5) is rotated, the handle neck 90 and the boss too also turn. However, the rotational movement is not transmitted to the handle spindle 94 the activating member 102 and the engaging member 104.

(51) The handle grip 88 is therefore disengaged from the handle spindle 94 such that the handle grip 88 is allowed to turn freely in relation to the handle spindle 94, thereby enabling a disengaged state of the handle device 86, a so-called free-swiveling function. In this position, it is therefore not possible, by means of the handle grip 88, to operate a tumbler, an espagnolette bolt or any other device to which the handle spindle 94 may be coupled. Thus, when the actuator to adopts the second position 46, the coupling device 110 adopts a disengaging position where the first element (the boss 100) and the second element (the cylindrical end section 98) are disengaged.

(52) While the present disclosure has been described with reference to exemplary embodiments, it will be appreciated that the present invention is not limited to what has been described above. For example, it will be appreciated that the dimensions of the parts may be varied as needed. Accordingly, it is intended that the present invention may be limited only by the scope of the claims appended hereto.