The present invention relates to a switching device.
An example of a known switching device is described in publication EP1719142.
One of the problems associated with the above mentioned known switching device is that a clearance angle between positions of a roll element corresponding to an ON-state and an OFF-state of switch contacts is relatively small, approximately 45°.
An object of the present invention is to provide a switching device so as to solve the above problem. The objects of the invention are achieved by a switching device which is characterized by what is stated in the independent claim. The preferred embodiments of the invention are disclosed in the dependent claims.
The invention is based on the idea of providing a switching device with at least one roll spring connected between a frame of the switching device and a roll element of the switching device, the at least one roll spring being adapted to rotate the roll element further from the position corresponding to the ON-state during an opening event. The roll element of the switching device according to the present invention is adapted to be rotated during an opening event first with at least one actuator spring operationally connected to the roll element through an actuator, and subsequently with the at least one roll spring connected between the frame and the roll element.
An advantage of the switching device of the invention is that there is a large clearance angle between positions of the roll element corresponding to an ON-state and an OFF-state of switch contacts. Due to the large clearance angle, the present invention enables reducing size of a switching device assembly. The large clearance angle provides adequate clearance between open switch contacts with smaller physical dimensions than a small clearance angle.
In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which
Each of the actuator springs 81 and 82 is a coils spring. Each of the actuator springs 81 and 82 is connected between the frame 2 and the actuator 8, and has a first low energy position, a second low energy position, and a dead-centre position located between the low energy positions. A spring constant of each of the actuator springs 81 and 82 is high. Each of the actuator springs 81 and 82 is adapted to be transferred both from the first low energy position to the dead-centre position and from the second low energy position to the dead-centre position by means of rotation of the control shaft 6 such that energy required for transferring the actuator springs 81 and 82 to the dead-centre position originates from the rotation of the control shaft 6.
Each of the actuator springs 81 and 82 is adapted to transfer from the dead-centre position to the first low energy position in a first actuator trip event. The drive system is adapted to rotate the roll element 4 towards the second position during the opening event by means of energy delivered by the first actuator trip event.
The actuator 8 is adapted to be rotated around an axis of rotation relative to the frame 2, and to co-operate with the roll element 4 for rotating the roll element 4 towards the second position during the opening event. The actuator 8 and the actuator springs 81 and 82 are located in a lower part 22 of the frame 2. The actuator 8 comprises a first actuator protrusion 851 and a second actuator protrusion 852 which are adapted to co-operate with a roll protrusion 405 provided on the roll element 4 for transferring torque from the actuator 8 to the roll element 4. The drive system is adapted to rotate the roll element 4 during the opening event to an intermediate position located between the first position and the second position by means of a mechanical contact between the first actuator protrusion 851 and the roll protrusion 405.
The roll element 4 is provided with a connection system comprising a first connection member 401 on one axial end of the roll element 4, and a second connection member 402 on the other axial end of the roll element 4. Each of the connection members 401 and 402 is adapted to connect the roll element 4 to a roll element of a corresponding pole module 70. In other words the roll element 4 is adapted to be connected to a switch contact system by means of the connection system for transferring the switch contact system between an ON-state and an OFF-state.
A rotation axis of the control shaft 6 is perpendicular to a rotation axis of the roll element 4. A rotation axis of the actuator 8 coincides with the rotation axis of the control shaft 6. The control shaft 6 extends through the roll element 4.
Each of the roll springs 41 and 42 is a coil spring. Each of the roll springs 41 and 42 has a first low energy position, a second low energy position, and a dead-centre position located between the low energy positions. Each of the roll springs 41 and 42 is adapted to transfer from the dead-centre position to the first low energy position in a first roll trip event. The roll springs 41 and 42 are adapted to rotate the roll element 4 to the second position during the opening event by means of energy delivered by the first roll trip event. A spring constant of each of the roll springs 41 and 42 is selected such that a torque adapted to be provided by the roll springs 41 and 42 to the roll element 4 is smaller than a torque adapted to be provided by the actuator springs 81 and 82 to the roll element 4 through the actuator 8.
The shaft cam 65 protrudes from the control shaft 6. The roll cam 45 protrudes from the roll element 4.
The roll element 4 is adapted to transfer from the second position to the first position in a closing event for transferring a switch contact system from the OFF-state to the ON-state. The shaft cam 65 is adapted to co-operate with the roll cam 45 during the closing event for rotating the roll element 4 from the second position towards the first position. The drive system is adapted such that during the closing event rotation of the control shaft 6 towards the ON-position first starts to rotate the roll element 4 towards the first position by means of co-operation between the shaft cam 65 and the roll cam 45, and later starts to rotate the actuator 8 by means of a mechanical contact between the control shaft 6 and the actuator 8.
Each of the actuator springs 81 and 82 is adapted to transfer from the dead-centre position to the second low energy position in a second actuator trip event. The drive system is adapted to rotate the roll element 4 towards the first position during the closing event by means of energy delivered by the second actuator trip event.
The control shaft 6 is connected to the actuator 8 through the free motion spring 10 such that the control shaft 6 is rotatable relative to the actuator 8 between a rest position in which the free motion spring 10 is in a low energy position, and an engagement position in which the free motion spring 10 is in a tensioned position. The free motion spring 10 is adapted to attempt to transfer the control shaft 6 to the rest position if the control shaft 6 is deflected therefrom.
A spring constant of the free motion spring 10 is low. A torque adapted to be provided by the actuator springs 81 and 82 to the actuator 8 is multiple compared to a torque adapted to be provided by the free motion spring 10 between the control shaft and the actuator 8.
In
In
In
There is friction in the switch contact system 77 between the first stationary contact member 701 and the rotatable contact member 703, and between the second stationary contact member 702 and the rotatable contact member 703. High spring constants of the actuator springs 81 and 82 ensure that the friction is overcome and the first actuator trip event is capable of rotating the roll element 4 away from the first position. Further, the high spring constants of the actuator springs 81 and 82 ensure that an angular velocity of the roll element 4 is sufficiently high during the opening event in order to keep duration of an electric arc in the switch contact system 77 adequately short.
In
In
In the mechanism shown in
The intermediate position of the roll element 4 is located at a 50° angle relative to the second position of the roll element 4. In an alternative embodiment an intermediate angle between the intermediate position and the second position is greater than or equal to 20°.
In the starting position of the closing event the mechanism is in the position shown in
In
In
From the starting position of the closing event to the position of
If the user releases the control shaft 6 in the position of
Between positions shown in
After the second actuator trip event has begun, rotation of the roll element 4 is completely independent from the user. This user independent movement comprises the last 50° of the rotation of the roll element 4 towards the first position. An angle velocity of the roll element 4 during the last 50° of the rotation towards the first position is high and depends on the actuator springs 81 and 82 and the roll springs 41 and 42.
It will be obvious to a person skilled in the art that the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.
Number | Date | Country | Kind |
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18168981.1 | Apr 2018 | EP | regional |