Control of spring(s) type for a high- or medium-voltage breaker furnished with a pawled free wheel coupling device

Abstract

The invention relates to a spring controller for high- or medium-voltage electric switchgear, the controller having a free-wheel coupling device between a crank handle or a motor and the drive shaft (1) for driving a switch contact of the switchgear and respectively providing coupling while the spring(s) (11) is/are being loaded and decoupling while the spring(s) is/are being released. The free-wheel mechanical device is incorporated in a toothed wheel (2) of the controller and includes at least one pawl (7, 70) meshing or not meshing with an inner set of teeth (4) of the toothed wheel (2).

Claims

1. A spring type controller for a high-voltage or medium-voltage switch, the controller comprising: at least one spring; a first toothed wheel adapted to be driven in rotation with a driving power; a shaft adapted to drive a movable contact of the switch in rotation during an operation of the switch; an arm secured to the shaft and connected to the at least one spring; and a free-wheel coupling device coupling the first toothed wheel with the shaft in order to transmit the driving power to the at least one spring so as to load the at least one spring, and uncoupling them in order to transmit torque from the loaded at least one spring to the movable contact but not to the driving power; the free-wheel coupling device comprising: a second toothed wheel having an outer periphery and an inner periphery, the entire outer periphery being provided with teeth permanently meshing with the first toothed wheel and the entire inner periphery being provided with teeth; a release element arranged proximate to the outer and inner peripheries of the second toothed wheel; and at least one pawl pivotally mounted on the arm and adapted to be in the following respective positions: meshing with the inner teeth of the second toothed wheel to load the at least one spring until the at least one spring reaches a compression top dead-center by rotation, in a given direction of rotation, of the second toothed wheel and of the arm thus meshing therewith; bearing mutually against the release element once the at least one spring reaches the compression top dead-center, thereby disengaging from the inner teeth by pivoting on the arm in a direction opposite to a direction of rotation of the second toothed wheel, while blocking the arm; and spaced apart from the release lever by action thereon, in order to unblock the arm and allow it to be driven in rotation by the release force from the at least one spring and in the same given direction of rotation, while the second toothed wheel remains stationary.

2. A spring controller according to claim 1, having a plurality of pawls adapted so that all of them are in the same positions simultaneously.

3. A spring controller according to claim 1, the release element being a lever that is pivotally mounted to enable it to be moved apart from the pawl.

4. High- or medium-voltage electric switchgear provided with at least one switch and including a spring controller according to claim 1.

5. Switchgear according to claim 4, being a dead-tank type gas insulated switchgear.

6. Switchgear according to claim 4, being a live-tank type air insulated switchgear.

7. Switchgear according to claim 4, the switch being a circuit breaker.

8. Switchgear according to claim 4, the controller having a single switch closure spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other advantages and advantageous characteristics of the invention appear better on reading the following detailed description made with reference to FIGS. 1 to 4, in which:

(2) FIG. 1 is a perspective view of a portion of a spring controller of the invention;

(3) FIG. 2 is a detailed perspective view of the FIG. 1 controller;

(4) FIGS. 3A and 3B are likewise detailed perspective views of the FIG. 1 controller shown respectively in the fully-loaded state of the closure spring of the controller and at the beginning of an operation of releasing the closure spring; and

(5) FIG. 4 is a cross-section view through the ratchet free-wheel coupling device of the invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

(6) FIGS. 1 and 2 are perspective views showing the controller of the invention that operates by storing energy in a spring, and as installed in a high-voltage circuit breaker.

(7) The spring controller of the invention includes a free-wheel mechanical coupling device between a crank handle or a motor (not shown) and the drive shaft 1 for driving a movable contact of the circuit breaker, the free-wheel operation serving to provide mechanical decoupling between the crank handle or the motor and the drive shaft 1 while the closure spring 11 is being released.

(8) More exactly, the controller firstly comprises a first toothed wheel referred to as an outlet wheel 10, that is driven directly or indirectly by a crank handle or by a motor.

(9) This outlet toothed wheel 10 is permanently engaged with straight teeth formed over the entire circumferential outer periphery 5 of a second toothed wheel 2 mounted on a bearing (not shown). In other words, this outlet toothed wheel 10 is permanently coupled to the toothed wheel 2.

(10) The second toothed wheel 2 has teeth 4 of a sloping shape on its inner periphery.

(11) Inside the inner periphery of the teeth of sloping shape, there is arranged an arm 3 that is secured to the rotary drive shaft 1 of the movable contact of the circuit breaker via a cam 12 that is shown in greater detail in FIG. 3A. As shown, the arm 3 is fastened to the end of the shaft 1 by screw fastening. Naturally, any other fastening technique may be envisaged. Thus, the drive shaft 1 and the arm 3 are adapted to rotate simultaneously.

(12) As can be seen better in FIG. 1, the arm 3 has a pivot 6 fastened thereto, which pivot is itself connected to a helical compression spring 11 via a transmission system comprising a chain 13, a deflector pulley, and a rod 14 bearing against the free end of the closure spring 11.

(13) A pawl 7 is mounted to pivot about a pin 9 at the free end of the arm 3. When it is in its non-pivoted position (upwards in the figures), the pawl 7 is in meshing engagement with the teeth 4 on the inner periphery of the second toothed wheel 2: thus, in this non-pivoted position, there is mechanical coupling between the wheel 2 and the arm 3 and thus the drive shaft to which it is fastened. When it is in its upwardly-pivoted position, the pawl 7 is not in meshing engagement with the teeth 4: thus, in this pivoted position, there is mechanical decoupling between the toothed wheel 2 and the arm 3. The pawl 7 is moved from its non-pivoted position to its upwardly-pivoted position during rotation of the arm 3 coupled to the toothed wheel 2 by the pawl coming into peripheral abutment against a lever 8, referred to as a trip lever. The trip lever 8 is a lever that pivots about a pin 80 and that is located in the proximity of the toothed wheel 2.

(14) It is specified at this point that because of the relative arrangement between the various elements of the closure spring, of the transmission system 12, 13, 14, and of the arm 3 with its pivot, as shown, the upwardly-pivoted position of the pawl 7 as reached by coming into peripheral abutment against the lever 8 (FIGS. 1, 3A, and 3B) corresponds to the top dead-center of the closure spring 11, i.e. to its maximally compressed state.

(15) The closure spring controller 11 of the invention also includes an anti-return device (not shown) having the function of preventing either directly the outlet toothed wheel 10 from rotating in the clockwise direction, or directly the toothed wheel 2 from rotating in the counterclockwise direction in the face view of the figures. The function of this anti-return device is explained below with reference to the operation of the controller. Such an anti-return device, which may be purely mechanical, may easily be arranged within the controller by the person skilled in the art without reducing the simplicity thereof.

(16) The operation of the spring controller of the invention is described below.

(17) When it is desired to load the closure spring 11, the outlet toothed wheel 10 is driven by a crank handle or a motor in the counterclockwise direction in the face view of the figures. The second toothed wheel 2 is then driven in rotation in the clockwise direction. The pawl 7 is then engaged with the teeth 4 of the inner periphery of the toothed wheel, and the arm 3 is thus coupled in rotation with the toothed wheel 2 to rotate in this clockwise direction: FIG. 4 shows more particularly the coupling between the coupling portion proper 70 of the pawl 7 and the complementary teeth 4 of sloping shape. This engagement between the pawl 7 and the toothed wheel 2 continues until the pawl 7 comes into peripheral abutment against the trip lever 8. In this position, the closure spring 11 is thus almost completely fully loaded. Full loading of the closure spring 11 (reaching top dead-center) is achieved when the pawl 7 reaches its upwardly-pivoted position by bearing against the lever 8. In this upwardly-pivoted position, the pawl 7 is no longer engaged with the teeth 4, i.e. it is disengaged therefrom: the arm 3 is thus decoupled from the toothed wheel 2. This position in which the pawl 7 is disengaged thus enables the toothed wheel 2 to continue to turn without changing the position of the arm 3. As a result, the motor or the crank handle driving the toothed wheel 2 via the outlet toothed wheel 10 may slow down progressively. This avoids imparting any damage to a mechanical element as a result of the motor or the crank handle stopping suddenly. In other words, an operator may continue to turn the handle or the motor may continue to run without giving rise to damage.

(18) Furthermore, because of the anti-return device, even if an operator turning the outlet toothed wheel 10 via the crank handle while loading the spring 11 should let go of the handle in untimely manner, the arm 3 cannot drive the toothed wheel 2 in the counterclockwise direction. In other words, the operator does not run the risk of being injured by the crank handle, since it cannot be driven in rotation by the toothed wheels 10, 2 that are blocked by the anti-return device.

(19) When the circuit breaker is to be closed in order to interrupt a current, the trip lever 8 is pivoted in the clockwise direction as shown better by the arrow in FIG. 3B. Once the trip lever 8 no longer bears against the pawl 7, the arm 3 is no longer blocked against rotating in the clockwise direction in the face view of the figures. Since the pawl 7 is also no longer engaged with the teeth 4 on the inner periphery of the toothed wheel 2, the arm 3 and the switch drive shaft 1 to which it is fastened then rotate in the clockwise direction under the traction force from the chain 13 generated by the force of the closure spring 11 releasing. In other words, they operate in a free-wheel configuration relative to the mechanically decoupled toothed wheel 2, which therefore remains stationary in rotation. The drive shaft 1 thus drives the movable contact of the circuit breaker by means of the cam 15.

(20) The closure spring controller 11 fitted with the free-wheel coupling device including the pawl 7 is simple to implement and does not include any rotary component presenting inertia that would prejudice the closure operation of the circuit breaker when the spring is released.

(21) Other improvements or variants may be provided without thereby going beyond the ambit of the invention.

(22) Thus, for example, although the controller is shown as having only a single pawl 7, it is possible to envisage arranging a plurality of pawls engaged with the teeth on an inner periphery of the toothed wheel: in such a configuration, it will naturally be understood that all of the pawls are respectively engaged and disengaged with the teeth simultaneously. In other words, the pivoting for enabling them to reach their position disengaged from the teeth is obtained simultaneously for all of the pawls.

(23) Furthermore, although shown with a transmission system (deflector pulley 12, chain 13), it is also possible to envisage a direct connection between one end of a spring and a pivot fastened on the arm, i.e. without making use of a chain and a pulley.

(24) Finally, although shown with only one closure spring, the controller of the invention may equally well incorporate a plurality of springs that are to be compressed.

(25) Likewise, although shown in the form of a helical spring, it is possible to use one or more spiral springs.

(26) The person skilled in the art will select the type of spring and the number of springs depending on the torque needed for driving the movable contact(s) of the switchgear and on the space available within the controller.