Tensioning gear for tensioning a storage spring of a spring storage drive

Description

[0001] The invention relates to a tensioning mechanism for tensioning a storage spring of a spring storage drive, in particular for a circuit breaker.

[0002] Spring-loaded actuators are primarily used for switching circuit breakers. Circuit breakers are electrical switches designed for high electrical currents and voltages, particularly to safely interrupt high overload and short-circuit currents. To this end, circuit breakers have a breaker unit with at least one movable switching element for opening and closing a current path. To move the switching elements during a switching operation, circuit breakers store the energy required for the operation. Spring-loaded actuators store this energy in storage springs, which are tensioned to store the energy. A storage spring is tensioned, for example, by a tensioning motor connected to the storage spring via a tensioning gearbox. Similarly, spring-loaded actuators are also used, for example, to switch load break switches.DE 196 42 031 A1 discloses an actuating device for a disconnect switch. US 2016 / 240330 A1 discloses a coupling mechanism for a circuit breaker drive. CN 201 956 270 U discloses a switching gear for a vacuum interrupter.

[0003] The invention is based on the objective of providing an improved tensioning mechanism for tensioning a storage spring of a spring storage drive.

[0004] The problem is solved according to the invention by the features of claim 1.

[0005] Advantageous embodiments of the invention are the subject of the dependent claims.

[0006] A tensioning device according to the invention for tensioning a storage spring of a spring storage drive comprises a tensioning wheel coupled to the storage spring, an intermediate shaft coupled to the tensioning wheel, an intermediate wheel driven by a tensioning motor, a freewheel coupled to the intermediate wheel, a locking mechanism for releasably locking the tensioning wheel in a tensioned state of the storage spring and a jaw coupling that couples the freewheel to the intermediate shaft for tensioning the storage spring and decouples it from the intermediate shaft in the tensioned state of the storage spring.

[0007] When the accumulator spring is tensioned, the intermediate shaft transmits rotations of the intermediate gear via the freewheel and the jaw clutch to the tensioning wheel, thus enabling the tensioning motor, which drives the intermediate gear directly or indirectly, to tension the accumulator spring. The locking mechanism allows the tensioning wheel to be locked in the tensioned state of the accumulator spring, so that the spring remains tensioned until the lock is released to release the energy stored in the spring. In the tensioned state of the accumulator spring, the jaw clutch decouples the intermediate shaft from the freewheel and the intermediate gear, preventing any forces from being transmitted from the intermediate gear to the intermediate shaft and the tensioning wheel, particularly during the overrun of the tensioning motor.Without the jaw coupling, these forces would be transmitted to the intermediate shaft and to components of the tensioning mechanism coupled to the intermediate shaft, such as components of the locking mechanism, when the accumulator spring is under tension, causing them to become stressed and strained. The jaw coupling therefore advantageously relieves the intermediate shaft and the components of the tensioning mechanism coupled to it when the accumulator spring is under tension.

[0008] The invention provides that the jaw coupling has a first clutch shoe fixed to the intermediate shaft and a second clutch shoe connected to the freewheel, wherein the first clutch shoe is displaceable between a first end position, in which it rests against the second clutch shoe, and a second end position, in which it is separated from the second clutch shoe and which it assumes when the accumulator spring is tensioned. Due to the fixed coupling of the first clutch shoe to the intermediate shaft, rotations of the intermediate shaft are transmitted to the first clutch shoe. The displaceability of the first clutch shoe enables its coupling to the second clutch shoe and the freewheel connected to it for tensioning the accumulator spring, and the decoupling of the clutch shoes when the accumulator spring is tensioned.

[0009] The first clutch shoe is coupled to the intermediate shaft by a coupling element. This coupling element is guided through a transverse opening in the intermediate shaft, perpendicular to one of its longitudinal axes, and is displaceable within this opening between a first position (defining the first end position of the first clutch shoe) and a second position (defining the second end position). The coupling element is, for example, designed as a tube or bolt whose longitudinal axis is perpendicular to the longitudinal axis of the intermediate shaft and whose ends project into recesses in the first clutch shoe. The coupling element allows the first clutch shoe to be displaced by moving the coupling element itself.

[0010] Furthermore, a switching pin is provided, for example, which is slidably mounted in a longitudinal opening in the intermediate shaft running along its longitudinal axis and is coupled to the coupling element. This allows the first clutch shoe to be moved between its end positions via the coupling element by sliding the switching pin.

[0011] Furthermore, it is provided, for example, that a release end of the switching pin protrudes from the longitudinal opening in the intermediate shaft, and a release element is arranged on the tensioning wheel. This release element moves the release end of the switching pin towards the longitudinal opening when the accumulator spring is tensioned, thus moving the coupling element from its first to its second position. For example, the release element has a contact end projecting radially from the tensioning wheel with an inclined contact surface that rests against the release end of the switching pin when the pin is moved. The release element couples the tensioning wheel to the switching pin in a position where the accumulator spring is tensioned, thereby moving the switching pin and opening the jaw coupling.

[0012] Preferably, each of the two clutch shoes extends in a ring shape around the intermediate shaft. This enables a simple and reliable coupling of the jaw clutch to the intermediate shaft and the freewheel.

[0013] Furthermore, a return spring coupled to the first clutch shoe is provided, which exerts a spring force on the first clutch shoe in the direction of its first end position when the first clutch shoe is in its second end position. The return spring allows the first clutch shoe to be pushed from its second end position to its first end position when the control element releases the switching pin upon releasing the accumulator spring. This closes the dog clutch, and the tensioning mechanism is then ready to re-tension the accumulator spring after it has been released.

[0014] The freewheel, for example, has a freewheel ring that runs around the intermediate shaft and to which the second clutch shoe is connected. This ensures reliable coupling of the dog clutch to the freewheel.

[0015] The intermediate gear, for example, can be driven by the tensioning motor via a bevel gear. This redirects the drive force of the tensioning motor, enabling a compact design of the spring-loaded drive.

[0016] The locking mechanism, for example, features a cam roller firmly connected to the tensioning wheel and a pawl that secures the cam roller to lock the tensioning wheel. This enables reliable, releasable locking of the tensioning wheel using a simple and cost-effective locking mechanism.

[0017] A spring-loaded storage drive according to the invention comprises a tensioning mechanism according to the invention. The advantages of such a spring-loaded storage drive result from the advantages of a tensioning mechanism according to the invention mentioned above.

[0018] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. These drawings show: FIG 1 a perspective and partially cutaway view of a clamping gear, and FIG 2 an enlarged detail of the Figure 1 .

[0019] Corresponding parts are marked with the same reference symbols in the figures.

[0020] The Figure 1 and 2show a tensioning mechanism 1 for tensioning a (not shown) storage spring of a spring storage drive in a perspective and partially cutaway view, wherein Figure 2 an enlarged section of the Figure 1 The storage spring, for example, is a switching spring of the spring storage drive that stores energy to close a current path of a circuit breaker. The tensioning gear 1 includes, among other things, a tensioning wheel 9, an intermediate shaft 2, and an intermediate gear 4.

[0021] The tensioning wheel 9 is rigidly connected to a cam disc 17 and a tensioning shaft 18 and is coupled to the storage spring via the tensioning shaft 18.

[0022] The intermediate gear 4 can be driven by a (not shown) tensioning motor via a bevel gear 19.

[0023] The intermediate shaft 2 is coupled to the tensioning wheel 9 and the intermediate gear 4 in order to transmit rotations of the intermediate gear 4 to the tensioning wheel 9 for tensioning the accumulator spring. The coupling between the intermediate shaft 2 and the tensioning wheel 9 is a gear coupling formed by a toothed ring of the tensioning wheel 9 and a corresponding toothed ring of the intermediate shaft 2.

[0024] The intermediate gear 4 is coupled to the intermediate shaft 2 via a freewheel 3 and a jaw coupling 20, with the freewheel 3 connecting the intermediate gear 4 to the jaw coupling 20. The jaw coupling 20 has a first coupling shoe 12 that is rotationally fixed to the intermediate shaft 2 and a second coupling shoe 11 that is connected to an inner freewheel ring 13 of the freewheel 3. Both coupling shoes 11 and 12 extend in a ring-like fashion around the intermediate shaft 2.

[0025] The first clutch shoe 12 is axially displaceable, i.e., parallel to a longitudinal axis 21 of the intermediate shaft 2, between a first end position, in which it rests against the second clutch shoe 11 and which it assumes when the accumulator spring is tensioned, and a second end position, in which it is separated from the second clutch shoe 11 and which it assumes when the accumulator spring is tensioned. This allows the jaw clutch 20 to couple the freewheel 3 and the intermediate gear 4 to the intermediate shaft 2 for tensioning the accumulator spring and to decouple the freewheel 3 and the intermediate gear 4 from the intermediate shaft 2 when the accumulator spring is tensioned.

[0026] The freewheel 3 decouples the intermediate gear 4 from the intermediate shaft 2 when tensioning the storage spring, when the tensioning shaft 18 passes over a top dead center.

[0027] In order to couple the first clutch shoe 12 to the intermediate shaft 2 in a rotationally fixed and axially displaceable manner, the first clutch shoe 12 and the intermediate shaft 2 have, for example, a toothed connection.

[0028] To move the first clutch shoe 12 from its first end position to the second end position, the intermediate shaft 2 has an elongated transverse opening 22 in the area of ​​the first clutch shoe 12, which runs perpendicular to the longitudinal axis 21 through the intermediate shaft 2. A coupling element 23, connected to the first clutch shoe 12, is guided through the transverse opening 22 and is displaceable within the transverse opening 22 between a first position, defining the first end position of the first clutch shoe 12, and a second position, defining the second end position of the first clutch shoe 12. In the embodiment shown in the figures, the coupling element 23 is designed as a tube whose ends project into recesses 24 in the first clutch shoe 12. Alternatively, the coupling element 23 can also be designed, for example, as a bolt.

[0029] Furthermore, the intermediate shaft 2 has a longitudinal opening 25 extending along its longitudinal axis 21, from the transverse opening 22 to an end of the intermediate shaft 2 on the tensioning wheel side. A switching pin 10 is axially displaceably mounted in the longitudinal opening 25, which has a control end 26 projecting from the longitudinal opening 25 and extends within the longitudinal opening 25 to the coupling element 23.

[0030] A control element 8 is arranged on the tensioning wheel 9. When the accumulator spring is tensioned, the control end 26 of the switching pin 10 is moved towards the longitudinal opening 25, thus moving the coupling element 23 from its first to its second position. The control element 8 has a contact end projecting radially from the tensioning wheel 9 with an inclined contact surface 27 that rests against the control end 26 of the switching pin 10 when the pin is moved. For example, the control element 8 is positioned on the tensioning wheel 9 such that the contact surface 27 contacts the control end 26 of the switching pin 10 when the tensioning wheel 9 has rotated approximately three degrees after the tensioning shaft 18 has reached top dead center.

[0031] A return spring 14 is also coupled to the first clutch shoe 12 and runs spirally around the intermediate shaft 2. The return spring 14 engages at an end of the first clutch shoe 12 facing away from the second clutch shoe 11 and, in the second end position of the first clutch shoe 12, exerts a spring force on the first clutch shoe 12 in the direction of the first end position.

[0032] The tensioning mechanism 1 also has a locking mechanism 28 for releasably locking the tensioning wheel 9 in the tensioned state of the accumulator spring. The locking mechanism 28 of the embodiment shown in the figures has a cam roller 5 arranged on the cam disk 17 and a pawl 6 that secures the cam roller 5 to lock the tensioning wheel 9. After the clutch shoes 11, 12 are separated, the cam roller 5 runs against the pawl 6 and is locked in this position by the pawl 6, for example, when the tensioning wheel 9 has rotated approximately ten degrees further after the tensioning shaft 18 has reached top dead center. The freewheel 3 and a backstop on an auxiliary shaft 7 coupled to the intermediate gear 4 prevent the cam roller 5 from rebounding from the pawl 6.

[0033] Since the clutch shoes 11, 12 are separated from each other when the accumulator spring is tensioned, the intermediate shaft 2 and its coupled components, such as the pawl 6 and the cam roller 5, are decoupled from the intermediate gear 4 when the accumulator spring is tensioned and are therefore not subjected to load and tension by the intermediate gear 4, for example, during overrun of the tensioning motor. This advantageously reduces the load on the pawl 6, the cam roller 5, and the freewheel 3, and prevents wear or damage to these components of the tensioning mechanism 1 caused by this load.

[0034] To release the energy stored in the tensioned accumulator spring, the coupling of the pawl 6 to the cam roller 5 is disengaged. The uncoiling accumulator spring rotates the tensioning wheel 9 in the same direction as when the accumulator spring was tensioned, causing the control element 8 to release the switching pin 10 again. The first clutch shoe 12 is then pushed from the second end position to the first end position by the return spring 14, thus re-engaging the jaw clutch 20. The tensioning mechanism 1 is then ready to tension the accumulator spring again.

[0035] Although the invention has been illustrated and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived by the person skilled in the art within the scope of protection of the claims.

Claims

1. A tensioning mechanism (1) for clamping a pre-loaded spring of a spring-loaded accumulator drive, the tensioning mechanism (1) comprising - tensioning wheel (9) coupled to the pre-loaded spring, - an intermediate shaft (2) coupled to the tensioning wheel (9), - an intermediate wheel (4) drivable by a tensioning motor, - a freewheel (3) coupled to the intermediate wheel (4), - a locking mechanism (28) for releasably locking the tensioning wheel (9) in a tensioned state of the pre-loaded spring, and - a claw coupling (20) which couples the freewheel (3) to the intermediate shaft (2) for clamping the pre-loaded spring and decouples it from the intermediate shaft (2) in the tensioned state of the pre-loaded spring, such that the claw coupling relieves the intermediate shaft and components of the tensioning mechanism coupled thereto in the tensioned state of the pre-loaded spring, characterized in that the claw coupling (20) has a first coupling jaw (12) non-rotatably coupled to the intermediate shaft (2) and a second coupling jaw (11) connected to the freewheel (3), wherein the first coupling jaw (12) is displaceable between a first end position, in which it abuts the second coupling jaw (11), and a second end position, in which it is separated from the second coupling jaw (11) and which it assumes in the tensioned state of the pre-loaded spring, and the first coupling jaw (12) is coupled to the intermediate shaft (2) by a coupling element (23), wherein the coupling element (23) is routed through a transverse opening (22) in the intermediate shaft (2) extending perpendicularly to a longitudinal axis (21) of the intermediate shaft (2) and is displaceable in the transverse opening (22) between a first position defining the first end position of the first coupling jaw (12) and a second position defining the second end position of the first coupling jaw (12) parallel to the longitudinal axis (21) of the intermediate shaft (2).

2. The tensioning mechanism (1) according to claim 1, characterised in that the coupling element (23) is designed as a tube or bolt, the longitudinal axis of which is arranged perpendicularly to the longitudinal axis (21) of the intermediate shaft (2) and the ends of which project into recesses (24) in the first coupling jaw (12).

3. The tensioning mechanism (1) according to claim 1 or 2, characterised by an actuating pin (10) which is displaceably mounted in a longitudinal opening (25) in the intermediate shaft (2) extending along the longitudinal axis (21) of the intermediate shaft (2) and is coupled to the coupling element (23).

4. The tensioning mechanism (1) according to claim 3, characterised in that a reset end (26) of the actuating pin (10) projects from the longitudinal opening (25), and a reset element (8) is arranged on the tensioning wheel (9) which displaces the reset end (26) of the actuating pin (10) toward the longitudinal opening (25) in the tensioned state of the pre-loaded spring, such that the coupling element (23) is displaced from its first to its second position.

5. The tensioning mechanism (1) according to claim 4, characterised in that the reset element (8) has a contact end projecting radially from the tensioning wheel (9) and having an oblique contact surface (27) which abuts the reset end (26) of the actuating pin (10) upon displacing the same.

6. The tensioning mechanism (1) according to any one of claims 1 to 5, characterised in that the two coupling jaws (11, 12) each extend annularly around the intermediate shaft (2).

7. The tensioning mechanism (1) according to any one of claims 1 to 6, characterised by a return spring (14) coupled to the first coupling jaw (12), which, in the second end position of the first coupling jaw (12), applies a spring force on the first coupling jaw (12) in the direction of the first end position.

8. The tensioning mechanism (1) according to any one of claims 1 to 7, characterised in that the freewheel (3) has a freewheel ring (13) extending around the intermediate shaft (2), and the second coupling jaw (11) is connected to the freewheel ring (13).

9. The tensioning mechanism (1) according to any one of the preceding claims, characterised in that the intermediate wheel (4) is drivable by the tensioning motor via a bevel gear (19).

10. The tensioning mechanism (1) according to any one of the preceding claims, characterised in that the locking mechanism (28) has a cam disc roller (5) fixedly connected to the tensioning wheel (9) and a latch (6) fixing the cam disc roller (5) for locking the tensioning wheel (9).

11. A spring-loaded accumulator drive having a tensioning mechanism (1) designed according to any one of the preceding claims.