WO2014095905A1

WO2014095905A1 - Draw out switching device

Info

Publication number: WO2014095905A1
Application number: PCT/EP2013/076956
Authority: WO
Inventors: Eric HAVERKAMP; Martin Geelen
Original assignee: Eaton Industries Netherlands BV
Current assignee: Danfoss Power Solutions II BV
Priority date: 2012-12-17
Filing date: 2013-12-17
Publication date: 2014-06-26
Anticipated expiration: 2015-06-17
Also published as: GB2514747A; GB201222720D0

Abstract

The invention relates to a drawout switching device comprising: a base frame for arrangement in a cabinet; a subframe slidable arranged in the base frame and housing switching gear; wherein the subframe is positionable in at least a connected position, a test position and a disconnected position; a lockable door hingedly arranged to the base frame; and operating means for operating the switching gear; wherein the operating means are arranged on a telescopic slidable door part arranged in the lockable door, wherein the slidable door part protrudes from the lockable door in the test position and disconnected position of the subframe.

Description

Draw out switching device

The invention relates to a drawout switching device comprising:

- a base frame for arrangement in a cabinet;

- a subframe slidable arranged in the base frame and housing switching gear;

wherein the subframe is positionable in at least a connected position, a test position and a disconnected position;

- a lockable door hingedly arranged to the base frame ; and

- operating means for operating the switching gear. Typical draw-out switches are used for low voltage applications such as switching pumps and electric motors. The draw-out switching devices are arranged in a cabinet which is provided with busbars to supply power and outgoing busbars to conduct switched power to for example a pump or motor. The switching gear of the draw-out switching devices provide for the connecting and disconnecting of the supply busbars to the outgoing busbars. This switch gear comprises safety circuitry and actuators to make or break contact between busbars.

For maintenance and problem solving, it is necessary that the switching gear can be tested. For this purpose, the switching gear has to be disconnected from the busbars. It is also desired that in such a test position the switching gear is connected to an auxiliary connector such that different components of the switching gear can be tested.

With a typical draw-out switch, the switch is partially pulled out of the cabinet such that the draw-out switch is disconnected from the busbars and the switching gear can be tested. In this test position the switching gear is connected to an auxiliary connector for testing the switch gear.

The draw-out switch is pulled out further to truly disconnect the switching gear. In this posi- tion the draw-out switching device can be removed safely. To show in which position the drawout device is positioned, it is known to use indicators arranged on the subframe and the base frame. This typically would require opening the lockable door, which is undesired due to safety requirements and due to the possibility of dust penetrating the cabinet.

It is also known to provide an opening in the lockable door, through which a part of the sub- frame can penetrate. Typically, this part comprises control lights and a knob for operating the switching gear on the subframe. The position of the subframe is in this embodiment indicated by the amount in which the part protrudes through the opening in the lockable door.

For cabinets with switch gear it is also desired to comply with a certain international protection rating, or IP rating. This rating defines requirements of a housing or cabinet with respect to aspects of contact with the interior components and contact with dust or water. The known opening in the lockable door to indicate the position of the subframe is difficult to seal and accordingly it is difficult to get a high IP rating. This is the result of the tolerances between the subframe and lockable door. On the other hand, a lockable door without any indication of the position of the subframe would be easy to seal and get a high IP rating. However, a drawout switching device typically would need operating means on the outside to operate the switch gear on the inside, and in particular an operating knob which is mechanically connected to the switching gear. With a movable subframe and a stationary base frame with stationary lockable door, this would require a complex mechanical connection between the operating knob and the switch gear.

It is an object of the invention to provide a drawout switching device in which the above mentioned disadvantages are reduced or even removed.

This object of the invention is achieved with a drawout switching device according to the pre- amble, which is characterized in that the operating means are arranged on a telescopic slidable door part arranged in the lockable door, wherein the slidable door part protrudes from the lockable door in the test position and disconnected position of the subframe. Because the operating means are arranged on the slidable door part, there can be a direct mechanical connection between the operating means and the switching gear arranged on the movable subframe. The telescopic slidable door part also provides the possibility to provide a better seal between the lockable door and the slidable door part, as it is not necessary to take into account any tolerances of the movable subframe. Because the slidable door part is arranged on the lockable door, a higher accuracy can be obtained. Preferably, in the drawout switching device according to the invention, the telescopic slidable door part comprises a tubular wall having a cross section adapted to the corresponding opening in the lockable door.

In a preferred embodiment of the drawout switching device according to the invention, a radi- ally extending flange is arranged at the outwardly directed end of the tubular wall.

With the flange extending on the outside, the flange will cover any gap between the lockable door and the slidable door part, in particular when the subframe is in the connected position and the door part is fully retracted into the lockable door.

In a further preferred embodiment of the drawout switching device according to the invention a sealing layer is arranged on the flange to seal the flange on the lockable door in the connected position of the subframe. The door part with the flange will be against the lockable door and with the sealing layer in between a good sealing is obtained such that a high IP rating can be achieved.

Yet another embodiment of the drawout switching device according to the invention comprises spring means for urging the slidable door part in the lockable door.

With the spring means it is possible to have a disconnectable connection between the operating means on the door part and the switching gear on the subframe. As a result, the lockable door can be opened without having to unmount the operating means. The spring means will ensure that with a closed door, the operating means will always be in operating contact with the switchgear on the subframe. So, when the subframe is moved from the connected position to the test position or the disconnected position, the door part will be pushed out of the locka- ble door against the spring force of the spring means.

In still another embodiment of the drawout switching device according to the invention the switching gear comprises a rotating contact member, the operating means comprise a rotating knob, and a shaft is arranged between the rotating contact member and the rotating knob. A further preferred embodiment of the drawout switching device according to the invention comprises a control panel slidably arranged on the subframe and connected to a window in the lockable door.

The control panel provides indicators, like lights, for indicating the state of the switching gear. When the subframe is moved from the connected position towards another position the control panel can slide relative to the subframe and thus remains stationary relative to the lockable door.

Preferably, the control panel comprises spring means for urging the control panel sealing against the window. The spring means ensure that the sliding control panel will always be pressed against the window, such that no dust or other particles can enter the cabinet through the window. It is also possible to arrange a transparent material in the window to fully seal this window.

These and other features of the invention will be elucidated in conjunction with the accompa- nying drawings.

Figure 1 shows a perspective view of an embodiment of the drawout switching device according to the invention. Figures 2 and 3 show a cross sectional view of the drawout switching device of figure 1 in two positions. Figure 4 shows a second cross sectional view of the device of figure 1 in disconnected position.

Figure 5 shows a second cross sectional view of the device of figure 1 in connected position.

Figure 1 shows an embodiment of a draw-out switching device 1 according to the invention. The switching device 1 has a base frame 2 on which a sub-frame 3 is slidably arranged.

The base frame 2 is preferably arranged in a cabinet with a back wall 4. This back wall 4 has busbars 5 for supply of power and connection blocks 6 to which for example a pump or electric motor is connected.

The sub-frame 3 is guided along a guide rail 8, which is attached to the base frame 2. A cam 9 arranged on a lever (not shown) is used to control the movement of the sub-frame 3.

At the back of sub-frame 3 a wall 10 is arranged with feeder contacts 11 and outgoing contacts 12. In the connected position as shown in figure 1, the feeder contacts 11 are in contact with the busbars 5, while the outgoing contact 12 is connected to the connection block 6. Switching gear 24 is connected to the feeder contacts 11 and the outgoing contacts 12 to switch power to the outgoing contact 12.

The front of the base-frame 2 has a door part 13 with a switch 14 and a separate control panel 25 with control lights 15. The door part 13 protrudes through an opening 16 in a door 17, which is arranged by hinges 18 to the base frame 2.

The door 17 has a latch 19 with an operating knob 20. The latch 19 interacts with a secondary latch 21, which prevents the sub-frame part 3 from moving out of the disconnected position, when the door 17 is not closed and not locked. An auxiliary connector 22, 23 is arranged with one part 22 to the base frame 2 and with the other part 23 to the sub-frame 3. Figure 2 shows a cross sectional view of the device 1 in the connected position as shown in figure 1. The switch 14 is mechanically connected with a shaft 26 via couple piece to the switching gear 24. The door part 13 is provided with a tubular wall 36 such that a telescopic movement in the opening 16 is possible. The outer edge of door part 13 provides a circumferential flange which is pressed against a seal 27 arranged around the opening 16.

Springs 28, 29 are provided to ensure that the outer edge of door part 13 is pressed against the seal 27 when the drawout switching device 1 is in the connected position.

Figure 3 shows the cross sectional view of figure 2, but with the drawout switching device 1 in the disconnected position. For this position, the subframe 3 is moved relative to the base frame 2. As a result, the switching gear 24 is moved towards the door 17 and also the shaft 26 is advanced accordingly. This will press door part 13 with switch 14 away from the lockable door 17 against the force of the springs 28, 29.

Figure 4 shows a second cross sectional view along the control panel 30, which comprises the control lights 15. The control panel 30 is arranged slidingly on the subframe 3 via a slot 31 and a guide pin 32. A spring 33 arranged between the subframe 3 and the control panel urges the control panel 30 against the seal 34 provided on the inside of door 17 around the window 35. So, independent of the position of the subframe 3 relative to the base frame 2, the control panel 30 will always be pressed against the seal 34 and ensure that no dust of moist can enter via the window 35.

Figure 4 shows the drawout switching device 1 in the disconnected position, whereas figure 5 shows the second cross sectional view along the control panel 30 when the drawout switching device 1 is in the connected position.

Claims

1. Drawout switching device comprising:

- a base frame for arrangement in a cabinet;

- a subframe slidable arranged in the base frame and housing switching gear;

- a lockable door hingedly arranged to the base frame ; and

- operating means for operating the switching gear; characterized in that the operating means are arranged on a telescopic slidable door part arranged in the lockable door, wherein the slidable door part protrudes from the lockable door in the test position and disconnected position of the subframe.

2. Drawout switching device according to claim 1, wherein the telescopic slidable door part comprises a tubular wall having a cross section adapted to the corresponding opening in the lockable door.

3. Drawout switching device according to claim 2, wherein a radially extending flange is arranged at the outwardly directed end of the tubular wall.

4. Drawout switching device according to claim 3, wherein a sealing layer is arranged on the flange to seal the flange on the lockable door in the connected position of the subframe.

5. Drawout switching device according to any of the preceding claims, comprising spring means for urging the slidable door part in the lockable door.

6. Drawout switching device according to any of the preceding claims, wherein the switching gear comprises a rotating contact member, the operating means comprise a rotating knob, and wherein a shaft is arranged between the rotating contact member and the rotating knob.

7. Drawout switching device according to any of the preceding claims, further comprising a control panel slidably arranged on the subframe and connected to a window in the lockable door.

8. Drawout switching device according to claim 7, wherein the control panel comprises spring means for urging the control panel sealing against the window.