Abstract
A snap-action drive for a switching device has an energy store, a swinging movable part and a securing device for the movable part. The securing device secures a position of the swinging movable part by a force effect, wherein a reversal of direction of the movable part takes place counter to the force effect.
Claims
1. A snap-action drive for a switching device, the snap-action drive comprising: an energy store; a gear mechanism having a swinging movable part; and a securing device for said swinging movable part, a reversal of direction of said swinging movable part takes place counter to a force effect of said securing device.
2. The snap-action drive according to claim 1, wherein said swinging movable part and said securing device form a bistable system.
3. The snap-action drive according to claim 1, wherein said swinging movable part assumes an unstable state when said energy store is charged.
4. The snap-action drive according to claim 1, wherein said swinging movable part acts as a lag element in said gear mechanism.
5. The snap-action drive according to claim 2, wherein said securing device has a dead-center spring.
6. The snap-action drive according to claim 5, wherein said energy store has a dead-center spring.
7. The snap-action drive according to claim 6, wherein a dead center of said dead-center spring of said securing device and of said energy store apply force effects to said swinging movable part in opposing directions.
8. The snap-action drive according to claim 6, wherein traversing of a dead center of said dead-center spring of said energy store, causes a stable state of said bistable system to change.
9. The snap-action drive according to claim 6, wherein a dead center of said dead-center spring of said securing device and of said energy store are traversed in chronological succession.
10. The snap-action drive according to claim 5, wherein said swinging movable part is driven by outputting of energy from said energy store of the snap-action drive.
11. The snap-action drive according to claim 1, wherein said gear mechanism has a slotted link, by means of said slotted link at least one of charging or discharging of said energy store is controlled.
12. The snap-action drive according to claim 11, wherein said slotted link has at least one end stop for bounding a movement which can be output by said gear mechanism.
13. The snap-action drive according to claim 1, wherein said swinging movable part is mounted in a rotationally movable fashion.
14. The snap-action drive according to claim 1, further comprising a storage charging mechanism having a two-armed storage-charging lever which is rotatably mounted.
15. The snap-action drive according to claim 14, wherein rotational axes of said swinging movable part and said two-armed storage-charging lever are oriented coaxially.
16. A switching device, comprising: a snap-action drive containing an energy store, a gear mechanism having a swinging movable part, and a securing device for said swinging movable part, a reversal of direction of said swinging movable part taking place counter to a force effect of said securing device; and switching contact pieces which can move relative to one another and whose relative movement can be brought about by said snap-action drive.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0043] FIG. 1 is an illustration showing a snap-action drive in a switched-off state according to the invention;
[0044] FIGS. 2, 3 and 4 are illustrations showing sequences of a movement of the snap-action drive during a switching-on process;
[0045] FIG. 5 is an illustration showing the snap-action drive in a switched-on state;
[0046] FIGS. 6, 7, 8 and 9 are illustrations showing sequences of a movement of the snap-action drive during a switching-off process; and
[0047] FIG. 10 is an illustration showing the snap-action drive in a switched-off state.
DETAILED DESCRIPTION OF THE INVENTION
[0048] Referring now to the figures of the drawings in detail and first, particularly to FIGS. 1-10 thereof, there is shown a snap-action drive 5 which serves to operate a switching device 1. The switching device 1 has a first switching contact piece 2 and a second switching contact piece 3. The two switching contact pieces 2, 3 can move linearly with respect to one another. End sides of the switching contact pieces 2, 3 which have complementary shapes face one another. The first switching contact piece 2 is connected to the snap-action drive 5 via a kinematic chain 4. A relative movement between the two contact pieces 2, 3 can be triggered by the snap-action drive 5. There is provision here that only the first switching contact piece 2 can be moved. It can also be provided that both the first and second switching contact pieces 2, 3 are arranged in a movable fashion. Correspondingly, if the kinematic chains are modified a movement can also be transmitted to both switching contact pieces 2, 3 in order to generate a relative movement. The second switching contact piece 3 is provided here with ground potential, with the result that the first switching contact piece 2 can conduct a ground potential via contact with the first switching contact piece 2. A reversal of the application of the ground potential can also be provided, with the result that, for example, ground potential is continuously applied to the first switching contact piece 2, and by switching on the switching device 1 ground potential can be applied to the second switching contact piece 3. As result it is possible, for example, to ground a phase conductor, which is to be grounded, via the switching device 1. Correspondingly, in this case the switching device 1 is referred to as a grounding switch. In this context, by virtue of the use of the snap-action drive 5 the grounding switch or the switching device 1 can function as a high-speed grounding switch, since snap-action switching off or switching on of both switching contact pieces 2, 3 takes place.
[0049] FIGS. 2 to 10 each represent the switched state of the switching device 1 with the first switching contact piece 2 and the second switching contact piece 3. The respective state of the snap-action drive 5 is represented in a complementary fashion with respect to the latter. In FIG. 1, the switching device 1 has a switched-off position, i.e. the switching contact pieces 2, 3 are electrically insulated from one another. FIG. 10 shows an identical switched-off position of the switching device 1. FIGS. 1 and 10 represent the snap-action drive 5 in the same state. The sequence of a switching-on movement at the switching device 1 and the corresponding sequences in the snap-action drive 5 are illustrated starting from the switched-off position in FIG. 1 via FIGS. 2, 3 and 4. A reversal of the switching device 1 from its switched-on position into its switched-off position is represented starting from the switched-on position in FIG. 5 via FIGS. 6, 7, 8, 9 and 10, wherein the respective sequences of the snap-action drive 5 are shown in the figures. FIGS. 1 and 10 correspond to one another here.
[0050] Firstly, the design of a snap-action drive 5 will be described in more detail with respect to FIG. 1. The snap-action drive 5 has a gear mechanism. The gear mechanism is provided with a gear shaft 6. The gear shaft 6 is part of the kinematic chain 4 which transmits a relative movement to the two switching contact pieces 2, 3. The gear shaft 6 is mounted in a positionally fixed fashion. A swinging movable part 7 is seated on the gear shaft 6. The swinging movable part 7 is embodied in the manner of a lever which projects radially from the gear shaft 6. A slotted link 8 is arranged on the swinging movable part 7. The slotted link 8 is arranged in the form of a continuous recess in the swinging movable part 7. The slotted link 8 is in the shape of a circular segment, wherein the circular segment is oriented coaxially with respect to the rotational axis of the gear shaft 6.
[0051] A storage-charging mechanism has a linear drive 9. The linear drive 9 is oriented in a positionally fixed fashion with respect to the bearing of the gear shaft 6. A linear movement can be generated by means of the linear drive. The linear drive acts on a storage-charging lever 10. The storage-charging lever 10 is embodied as a two-armed storage-charging lever and has a first driver 11 and a second driver 12. A movement can be input into the rotatably mounted storage-charging lever 10 by use of the linear drive 9, with the result that a rotational movement of the storage-charging lever 10 can take place. In this context, the rotational axes of the storage-charging lever 10 and of the swinging movable part 7 are oriented coaxially. The drivers 11, 12 project radially to such an extent that when a rotational movement occurs and the slotted link 8 is passed through they project into the slotted link 8.
[0052] The snap-action drive 5 also has an energy store 13. The energy store 13 is equipped with a storage spring 14. The storage spring 14 is a compression spring which bears with one of its ends on a positionally fixed bearing point 15. The positionally fixed bearing point is positioned here with a rigid angle with respect to the linear drive 9 and with respect to the bearing of the gear shaft 6. In this context, the positionally fixed bearing point 15 is embodied in such a way that a pivoting movement of the energy store 13 about the positionally fixed bearing point 15 is made possible. As a result, a change in length, which is performed when the energy store 13 is compressed, can be transferred from a pivoting movement about the positionally fixed bearing point 15, with the result that a rotational movement of the energy store 13 about the positionally fixed bearing point 15 is made possible. A linear displacement of the energy store 13 can be superimposed on a pivoting movement about the positionally fixed bearing point 15. At the end facing away from the positionally fixed bearing point 15, the energy store 13 can be equipped with a bolt 16, wherein the bolt 16 projects into the slotted link 8. Therefore, forcible guidance of the bolt 15 takes place within the slotted link 8. That is to say when there is rotational movement of the energy store 13 about the positionally fixed bearing point 15, the bolt 16 and the end of the energy store 13 facing away from the positionally fixed bearing point 15 can move freely within the slotted link 8. As a result, a forced change in the distance from the positionally fixed bearing point 15 to the bolt 16 can be forcibly brought about, by which means tensioning or relaxing of the storage spring 14 of the energy store 13 can be forcibly brought about.
[0053] In order to secure the swinging movable part 7 in the respective end positions of a swinging movement, a securing device 17 is provided. The securing device 17 has a compression spring which is positioned in a positionally fixed fashion by one of its ends and is attached by its other end to the swinging movable part 7. In this context, the attachment point to the swinging movable part 7 is selected such that the securing device 17 presses the swinging movable part 7 into an end position in each case, wherein between the end positions which form a stable position with the securing device 17 there is an unstable position within which the securing device 17 acts as a dead-center spring (see switching over between FIGS. 4 and 3, changeover of the position of the securing device 17).
[0054] FIG. 1 shows a switched-off position of the switching device 1. In the text which follows, a changeover of the switched state of the switching device from OFF to ON using the snap-action drive 5 will be described with reference to FIGS. 1, 2, 3 and 4.
[0055] In the case of a switching-on process, the linear drive 9 is firstly activated, as result of which a rotational movement is transmitted in the clockwise direction to the storage-charging lever 10. The storage-charging lever 10 rotates about its rotational axis, wherein the first driver 11 dips in a radially protruding fashion about the hatched area of the swinging movable part 7 and in the process moves into the slotted link 8. The first driver 11 impacts against the bolt 16 of the energy store 13 there and drives the bolt 16 through the slotted link 8 in the clockwise direction.
[0056] FIG. 2 shows an advanced position of the first driver 11 of the storage-charging lever 10, wherein shortening of the distance from the positionally fixed bearing point 15 to the bolt 16 occurs with the compression of the storage spring 14 of the energy store 13. Being secured by the securing device 17, the swinging movable part 7 remains at rest. The switching device 1 and the switching contact pieces 2, 3 of the switching device 1 remain at rest. Subsequently, the first driver 11 drives the bolt 16 through the slotted link 8, as result of which increasing charging of the energy store (compression of the storage spring 14) takes place. The securing device 17 acts against the friction forces acting between the energy store 13 (in particular bolt 16) and the swinging movable part 7 (in particular slotted link 8), with the result that the swinging movable part 7 remains at rest.
[0057] The energy store 13, in particular the storage spring 14, is in the dead-center position according to FIG. 3. In the dead-center position, the direction of action of the energy store 13 runs through the rotational axis of the oscillating movable part 7. When this dead-center position is passed through, driven by the first driver 11, the energy store 13/the bolt 16 leaves the dead-center position and impacts against an end stop 18 of the slotted link 8, on which the storage spring 14 presses to bring about discharging. The generation of force by the energy store 13 which now occurs is greater here than the force effect of the securing device 17, with the result that the force effect of the securing device 17 is overcome by the energy store 13. The securing device 17 or its compression spring firstly runs through a dead center, wherein the force effect of the securing device 17 is directed toward the force effect of the energy store 13 until the dead center is reached. When the dead center position of the securing device 17 is moved through, the direction of the force effect of the securing device 17 changes and assists the driving force of the energy store 13 and drives, together with the energy store 13, the swinging movable part 7 on the basis of the bolt 16 bearing against the end stop 18, as result of which a rotational movement of the gear shaft 6 is forcibly brought about. The first and second switching contact pieces 2, 3 are subjected to a relative movement. The two switching contact pieces 2, 3 are in contact with one another. This position is shown in FIG. 4. In order to permit positions to be secured by means of the securing device 17, the second driver 12 is moved completely out of the slotted link 8 by the first and second switching contact pieces 2, 3 (FIG. 5) upon reaching the switched-on position. The swinging movable part 7 is now held by the securing device 17 in a second end position of the swinging movable part 7 (if appropriate supported by the pre-tensioned energy store 13).
[0058] A switching-off movement is shown starting from FIG. 5 via FIGS. 6, 7, 8, 9 and 10. In this context, the movement which is to be transmitted to gear shaft 6 is reversed. The linear drive 9 drives the storage-charging lever 10 in the counterclockwise direction, as result of which the second driver 12 is moved into the slotted link 8. The second driver 12 comes into contact there with the bolt 16 of the energy store 13 (see changeover from FIG. 5 to FIG. 6), as result of which the bolt 16 is driven into the slotted link 8. The swinging movable part 7 is held in a positionally fixed fashion under spring loading by the securing device 17. Furthermore, as the rotational movement of the storage-charging lever 10 proceeds in the counterclockwise direction the bolt 16 is driven by the slotted link 8 up to the time at which the energy store 13 assumes a dead-center position (FIG. 7) with the storage spring 14 in the charged state. That is to say the force effect of the energy store 13/of the storage spring 14 runs through the center of rotation of the gear shaft 6. When the bolt 16 is driven by the dead center of the energy store 13 (brought about by the second drive 12), the now charged energy store 13 discharges. The energy store 13 with its bolt 16 impacts against a second end stop 19 of the slotted link 8, wherein the force effect of the securing device 17 first has to be overcome by the energy store 13. The swinging movable part 7 is continuously force-loaded by the securing device 17 and is driven out from a stable end position (this state is illustrated in FIG. 7). In FIG. 8 the dead-center position of the energy store 13 has just been left. The bolt 16 has become detached from the second driver 12 and impacts against the second end stop 19 and is about to move the swinging movable part 7 in the counterclockwise direction and by this means trigger a movement of the gear shaft 6. FIG. 9 shows snap-action-like shifting of the swinging movable part 7 and a corresponding snap-action-like switching-off movement of the switching contact pieces 2, 3 which can move relative to one another. The linear drive 9 then pushes the first driver 11 out of the slotted link 8, with the result that the end position of the swinging movable part 7 is secured by using the force effect of the securing device 17.
