Safety brake device

1. A safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) for use in a conveyance system ( 10 ) including a guide rail ( 20 ) and a component ( 16 ) moveable along the guide rail ( 20 ), the safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ) comprising:

a safety brake ( 48 ) moveable between a non-braking position where the safety brake ( 48 ) is not in engagement with the guide rail ( 20 ) and a braking position where the safety brake ( 48 ) is engaged with the guide rail ( 20 );

an actuator ( 52 ; 152 ; 252 ; 352 ; 452 ) for the safety brake ( 48 ), the actuator ( 52 ; 152 ;

252 ; 352 ; 452 ) comprising:

a mounting portion ( 42 ) for mounting the actuator ( 52 ; 152 ; 252 ; 352 ; 452 ) to the component ( 16 ),

a pad ( 54 ; 154 ; 254 ; 354 ; 454 ) arranged to be moveable relative to the mounting portion ( 42 ) between a first position spaced from the guide rail ( 20 ) and a second position in contact with the guide rail ( 20 ), and

at least one biasing member ( 56 ) configured to apply a biasing force to move the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) from the first position to the second position;

and a linkage mechanism ( 50 ) coupled between the safety brake ( 48 ) and the actuator ( 52 ; 152 ; 252 ; 352 ; 452 ) such that, when the mounting portion ( 42 ) is moving downwards relative to the guide rail ( 20 ), movement of the pad ( 54 ) to the second position creates an upwards reaction force transmitted by the linkage mechanism ( 50 ) to move the safety brake ( 48 ) into the braking position;

wherein the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) comprises a ferromagnetic material and the actuator ( 52 ; 152 ; 252 ; 352 ; 452 ) further comprises an electromagnet ( 62 ; 162 ; 262 ; 362 . operable to apply a magnetic field to the ( 54 ; 154 ; 254 ; 354 ; 454 ) and thereby create a magnetic force acting against the biasing force to move the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) towards the first position;

wherein the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) is connected to a support ( 58 ; 158 ; 258 ; 358 ; 458 ) which is movable upwards relative to the mounting portion ( 42 ; 142 ) in response to the upwards reaction force, wherein the biasing member extends between the pad and the support.

2. The safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ) of claim 1 , wherein the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) is non-magnetic.

3. The safety brake device ( 40 ; 140 ) of claim 1 , wherein the electromagnet ( 62 ) comprises an electrical coil ( 66 ) and a ferromagnetic core ( 64 ), and wherein the pad ( 54 ; 154 ) includes a reset portion ( 84 ) that is arranged in the first position to form part of the ferromagnetic core ( 64 ).

4. The safety brake device ( 40 ; 140 ) of claim 1 , wherein the electromagnet ( 62 ) is fixed relative to the mounting portion ( 42 ).

5. The safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) of claim 1 , further comprising a bearing surface ( 60 ; 160 ) arranged between the support ( 58 ; 158 ; 258 ; 358 ; 458 ) and the mounting portion ( 42 ; 142 ) which enables upwards movement of the support ( 58 ; 158 ; 258 ; 358 ; 458 ) relative to the mounting portion ( 42 ; 142 ).

6. The safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) of claim 1 , comprising at least one guiding rod ( 70 ; 170 , 270 , 370 ) arranged to connect the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) to the support ( 58 ; 158 ; 258 ; 358 ; 458 ) so as to guide lateral movement of the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) from the first position to the second position relative to the support ( 58 ; 158 ; 258 ; 358 ; 458 ).

7. The safety brake device ( 240 ; 340 ; 440 ; 540 . of claim 1 , wherein the electromagnet ( 162 ; 262 ; 362 ) is connected to the support ( 258 ; 358 ; 458 ) so as to be moveable relative to the mounting portion ( 42 ; 142 ).

8. The safety brake device ( 240 ; 340 ; 440 ; 540 ) of claim 7 , wherein the electromagnet ( 162 ; 262 ; 362 ) is connected to the support ( 258 ; 358 ; 458 ), and the at least one biasing member ( 256 ; 356 ) is connected to the support ( 258 ; 358 ; 458 ) and to the pad ( 254 ; 354 ; 454 ), in a symmetrical arrangement such that the biasing force applied to move the pad ( 254 ; 354 ; 454 ) from the first position to the second position is opposed by the magnetic force without applying a torque to the pad ( 254 ; 354 ; 454 ).

9. The safety brake device ( 540 ) of claim 1 , wherein the support ( 458 ) comprises a surface ( 160 ) arranged to move upwards and downwards relative to the mounting portion ( 142 ), the surface ( 160 ) oriented at an acute angle (α) relative to a direction of lateral movement of the pad ( 254 ) between the first position and the second position.

10. The safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) of claim 1 , wherein the mounting portion ( 42 ; 142 ) also mounts the safety brake ( 48 ) to the component ( 16 ) such that the safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) is a single integrated unit.

11. An elevator system ( 10 ) comprising an elevator car ( 16 ) driven to move along at least one guide rail ( 20 ), and the safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) of claim 1 , wherein the mounting portion ( 42 , 142 ) is mounted to the elevator car ( 16 ) and the safety brake ( 48 ) is arranged to be moveable between the non-braking position where the safety brake ( 48 ) is not in engagement with the guide rail ( 20 ) and the braking position where the safety brake ( 48 ) is engaged with the guide rail ( 20 ).

12. The elevator system ( 10 ) of claim 11 , comprising a speed sensor ( 76 ) and a safety controller ( 78 ) arranged to receive a speed signal ( 80 ) from the speed sensor ( 76 ) and to selectively reduce or disconnect an electrical power supply to the electromagnet ( 62 ; 162 ; 262 ; 362 ) upon detecting an overspeed or over-acceleration condition for the elevator car ( 16 ) based on the speed signal; and/or

comprising an accelerometer ( 84 ) and a safety controller ( 78 ) arranged to receive an acceleration signal ( 86 ) from the accelerometer ( 84 ) and to selectively reduce or disconnect an electrical power supply to the electromagnet ( 62 ; 162 ; 262 ; 362 ) upon detecting an over-acceleration condition for the elevator car ( 16 ).

13. A method of operating a safety brake in a safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ), the safety brake ( 48 ) moveable between a non-braking position where the safety brake ( 48 ) is not in engagement with a guide rail ( 20 ) and a braking position where the safety brake ( 48 ) is engaged with a guide rail ( 20 ), the safety brake device ( 40 ; 140 ; 240 ; 340 ; 440 ; 540 ) comprising:

an actuator ( 52 ; 152 ; 252 ; 352 ; 452 ) comprising:

a mounting portion ( 42 ) for mounting the actuator ( 52 ; 152 ; 252 ; 352 ; 452 ) to a component ( 16 ) moveable along a guide rail ( 20 );

a pad ( 54 ; 154 ; 254 ; 354 ; 454 ) arranged to be moveable relative to the mounting portion ( 42 ) between a first position spaced from the guide rail ( 20 ) and a second position in contact with the guide rail ( 20 ), the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) comprising a ferromagnetic material;

at least one biasing member ( 56 ) configured to apply a biasing force to move the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) from the first position to the second position; and

an electromagnet ( 62 ; 162 ; 262 ; 362 ); and

a linkage mechanism ( 50 ) coupled between the safety brake ( 48 ) and the actuator ( 52 ; 152 ; 252 ; 352 ; 452 ); the method comprising:

operating the electromagnet ( 62 ; 162 ; 262 ; 362 ) in a normal mode to apply a magnetic field to the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) and thereby create a magnetic force acting against the biasing force to move the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) towards the first position; and

operating the electromagnet ( 62 ; 162 ; 262 ; 362 ) in an emergency stop mode to reduce or remove the magnetic force acting against the biasing force such that the pad ( 54 ) moves to the second position to create an upwards reaction force when the mounting portion ( 42 ) is moving downwards relative to the guide rail ( 20 ), the upwards reaction force being transmitted by the linkage mechanism ( 50 ) to move the safety brake ( 48 ) into the braking position;

wherein the pad ( 54 ; 154 ; 254 ; 354 ; 454 ) is connected to a support ( 58 ; 158 ; 258 ; 358 ; 458 ) which is movable upwards relative to the mounting portion ( 42 ; 142 ) in response to the upwards reaction force, wherein the biasing member extends between the pad and the support.

14. The method of claim 13 , further comprising:

detecting an overspeed or over-acceleration of the component ( 16 ); and

initiating the emergency stop mode by selectively reducing or disconnecting an electrical power supply to the electromagnet ( 62 ; 162 ; 262 ; 362 ).