Control device of the spring type particularly for a high-voltage or medium-voltage circuit breaker or switch

The control device possesses a rigid main part combining most of the functional elements of this type of control device. It is made up of two portions of a rotary shaft, having placed between them a cam and a support arm that are connected together by a pivot that is offset relative to the axis of rotation. A toothed wheel having an inner set of teeth is placed around the support arm that is provided with a rachet system. The toothed wheel has an outer set of teeth-driven by a motor, via an intermediate gearwheel. The pivot controls the compression of the actuator spring by the assembly rotating. The device is applicable to high and medium voltage circuit breakers and switches.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

The present application is a National Stage Application of International Application No. PCT/EP2013/074876 entitled “CONTROL DEVICE OF THE SPRING TYPE PARTICULARLY FOR A HIGH-VOLTAGE OR MEDIUM-VOLTAGE CIRCUIT BREAKER OR SWITCH” filed Nov. 27, 2013, which claims priority to French Patent Application Number 12 61348 filed Nov. 28, 2012, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to an actuator assembly, also known as a “control mechanism”, of the type in which energy is accumulated in one or more springs, commonly referred to as a “spring control mechanism” for a high or medium voltage circuit breaker or switch, and including a freewheel coupling device, i.e. a rachet system.

PRIOR ART AND PROBLEM POSED

Spring type control devices exist for high or medium voltage switches and circuit breakers, in particular for circuits breakers and switches for gas insulated switchgear (GIS). These types of control device use energy, such as torque, for closing and opening the movable contacts of the switch or circuit breaker device. Three technologies are used in this type of control device: hydraulic devices; pneumatic devices; and spring devices. The present invention relates to spring type devices. The invention is therefore applicable in gas insulated installations (GIS), but may be applied equally well to air insulated installations, and also to indoor or outdoor installations.

The technique concerned by the control device of the invention combines a rachet system for loading a spring, i.e. a freewheel system, with a cam system for controlling the switch or the circuit breaker.

Patent document WO 2008/117437 A1 describes an energy accumulator device of the spring type for switchgear. In that type of device, a motor is coupled to a closure spring22via a gearwheel16, an intermediate gearwheel33, and a primary toothed wheel5. The closure spring22is connected to the primary toothed wheel5, which is made up of three coaxial gearwheels A, B, and C. The gearwheel B has an outer set of teeth35over its entire periphery, whereas the gearwheels A and C are provided with respective sets of teeth34aand34bover only respective fractions of a circular arc. While the closure spring is being loaded, the motor3drives the toothed wheel16in the clockwise direction. It therefore drives the intermediate toothed wheel33in the opposite direction. This intermediate toothed wheel33meshes with the primary toothed wheel5. When the closure spring22is fully loaded, the toothless section34ensures that the intermediate toothed wheel33and the toothed wheel16, together with the motor3, no longer turn together with the gearwheel A. The toothless section34decouples the motor3from the gearwheel A and prevents the motor from being damaged as a result of the system being constrained to stop.

A rachet system having pawls41a,41bis used on the gearwheel C and co-operates with the inner teeth36of the gearwheel B. When the closure spring is fully loaded, the gearwheel C stops turning because of its non-toothed section34b. Nevertheless, the gearwheel B, driven by the pawls41a,41b, is no longer engaged with the inner set of teeth of the gearwheel B.

The closure operation of the device may thus take place by the closure spring22relaxing.

That solution requires at least two gearwheels A and B to be used in combination in order to load the closure spring22and to drive the movable contacts of the switch. The gearwheel A is needed because of its non-toothed section34athat serves to allow the gearwheel A to stop on reaching dead-center, with the closure spring being fully loaded. The gearwheel B is needed for driving the movable contacts.

With that solution, the closure operation is relatively slow because of the need for the gearwheels A and B, the intermediate toothed wheel33, and the rachet system to operate simultaneously.

It should also be observed that patent document U.S. Pat. No. 4,491,709 also describes a spring control system using a rachet system for switch applications.

In all of the devices proposed, the overall size of the devices is not negligible. Unfortunately, there is a need to be able to have control devices that are relatively compact. This is particularly advantageous for gas insulated switches of the kind frequently installed in built-up areas, where space is limited. Furthermore, there is a need to limit the number of mechanical moving parts that make up such a control system in order to avoid risks of failure in the mechanism. Furthermore, that can also improve the compactness of the device.

SUMMARY OF THE INVENTION

To this end, the invention mainly provides a spring type control device comprising:a spring for rapidly delivering energy in order to move a movable contact of a circuit breaker or a switch;a rotary shaft for transmitting the energy needed for loading the spring;a toothed wheel receiving the energy via an outer set of teeth and serving to drive the rotary shaft while loading the spring;a rachet system for coupling and uncoupling the toothed wheel and the rotary shaft;a cam secured to the rotary shaft for transmitting the energy delivered by the spring to the movable contact;a support arm secured to the rotary shaft and carrying a rachet system, with the toothed wheel being placed around the spring arm; anda pivot fastened to the arm, the pivot being axially offset relative to the rotary shaft and mechanically connected to the spring.

According to the invention, the rotary shaft, the cam, the support arm, and the pivot form a single crankshaft-shaped part, the pivot being placed in the middle of this set of parts, between the support arm and the cam, the pivot being connected to one end of the spring by a loading rod having its other end mounted to pivot on the pivot, like a connecting rod, the rotary shaft comprising two portions, one beside the cam and the other beside the support arm.

In a main embodiment of the invention, the support arm has at least three angularly offset branches, with peripheral surfaces supporting the toothed wheel by making contact with the tips of teeth of the inner set of teeth of the toothed wheel, the rachet system being placed on one of the branches of the support arm to co-operate with the inner set of teeth of the toothed wheel.

Two other main aspects of the invention are a circuit breaker and a switch making use of the above-described device.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

FIG. 1shows a device of the invention without the energy-supply spring and the loading connecting rod that connects the spring to the elements shown inFIG. 1. Among the main elements shown in this figure, there is a toothed wheel1, having an inner set of teeth2and an outer set of teeth3. The outer set of teeth3serves to receive energy for loading the spring, e.g. as delivered by a motor via a toothed gearwheel (not shown) that meshes with the outer set of teeth3of the toothed wheel1.FIG. 1also shows a cam4having a functional outside surface4A that is used to actuate the movable contact(s) of the electrical installation for engaging or disengaging. The cam4is connected via a pivot5constituted by a shaft segment to a support arm6placed inside the toothed wheel1. One of the functions of the support arm6is to support the wheel. In the embodiment shown inFIG. 1, the support arm6is in the form of a star having three branches6B, but that is merely an example, and embodiments with four branches6B or even more could also be envisaged. The outside surface6A of the support arm6must be capable of being in contact with the tips of the teeth of the inner set of teeth2of the toothed wheel1.

On either side of the assembly constituted by these four elements, there is the rotary shaft of the device in two portions7A and7B. These two portions7A and7B are coaxial and they are designed to be supported by bearings. The pivot5is offset axially from the rotary shaft7A,7B.

It can thus be seen that the rotary shaft7A,7B, the cam4, the pivot5, and the support arm6are constituted and fabricated as a single part. This unit has the general shape of a crankshaft. Naturally, the various elements making up this unit are prevented from moving relative to one another.

Beside the toothed wheel1, there can be seen an inner rim1A extending around the entire circumference of the toothed wheel1. This enables the wheel to be positioned relative to the arm6of overall diameter greater than the inside diameter of the lateral rim1A.

The pivot5serves to connect the unit shown inFIG. 1mechanically to one or more springs for delivering the energy needed for opening or closing the electrical installation. In order to simplify the depiction of the embodiment, no spring is shown inFIG. 1. Nevertheless, the pivot5serves to communicate the energy transmitted by the set of elements shown inFIG. 1to a compression spring via a connecting rod that is likewise not shown.

A pawl8pivotally mounted on one end of a branch6B of the support arm6co-operates with the inner set of teeth2of the toothed wheel1to form a rachet system. The end of the pawl8thus penetrates between two teeth of the inner set of teeth2of the toothed wheel1. When the wheel turns clockwise, the pawl8is engaged between two teeth of the inner set of teeth2of the toothed wheel1. Under such circumstances, both portions7A and7B of the rotary shaft, the support arm6, and the cam4turn by the same amount in the clockwise direction together with the toothed wheel1.

In contrast, if the support arm6turns clockwise, the pawl8tends to disengage from the inner set of teeth2of the toothed wheel1. Thus, the assembly secured to the support arm6no longer transmits any mechanical moment or energy to the toothed wheel1.

The presence of a rachet system is needed for loading the spring. This stage of loading the spring is performed by means of an electric motor driving the toothed wheel1clockwise by means of an auxiliary wheel (not shown). Still while loading the spring, the pawl thus remains engaged between two teeth of the inner set of teeth2of the toothed wheel1and all of the elements shown inFIG. 1turn together clockwise. Thus, the pivot5can transmit to the connecting rod the movement that serves to compress the closure spring.

While it is loading the closure spring, when this turning assembly reaches bottom dead-center, i.e. when the connecting rod is in alignment with the closure spring, the spring relaxes. It then drives the pivot5and the support shaft in the same direction of rotation as before, but at a very much greater speed. As a result of this acceleration in the rotation of the support arm, the pawl8disengages from the teeth of the inner set of teeth2of the wheel1. The wheel1is therefore not driven in rotation and does not transmit a jolt to the drive motor.

FIG. 2shows more clearly the support arm6with the rachet device and the toothed wheel1, which wheel is placed around the support arm.

The rachet system operates as follows. The pawl8is mounted to pivot at one end of a branch of the support arm6, by means of a small pivot pin9. By means of this pivoting connection, the pawl8can occupy two positions. InFIG. 2, the position shown is the position in which the pawl8is engaged between two teeth of the inner set of teeth2of the toothed wheel1. In this position, the support arm6and the toothed wheel1turn together. The second position is the position in which the pawl8has been able to pivot about its pivot axis9in the counterclockwise direction. In this second position, the pawl8is disengaged from the teeth of the inner set2of the toothed wheel1. As a result, the support arm6and the toothed wheel1can turn separately relative to each other without transferring force or mechanical moments between each other.

FIG. 2also shows the cam4and the inner rim1A of the toothed wheel1.

FIG. 3shows clearly the crankshaft shape of a large portion of the elements of the device that constitutes a single mechanical part, i.e. the two portions7A and7B of the rotary shaft, the cam4, the pivot5, and the support arm6.

The pivot5, which is placed between the cam4and the support arm6, is offset axially relative to the rotary shaft7A,7B. It can thus be seen that during a rotation of the rotary shaft7A and7B, the position of the pivot5relative to an axis perpendicular to the axis ofFIG. 3varies. This position variation corresponds to the variation in the compression of the closure spring.

FIG. 4reproduces the assembly shown inFIG. 3, i.e., the rotary shaft7A,7B, the cam4, the pivot5, and the support arm hidden by the toothed wheel1. A connecting rod11is pivotally mounted on the pivot5at a first end11A. It is connected at a second end11B to a plate12having a first end10A of the closure spring10placed thereon, which spring in this type of embodiment is a helical spring. It should be observed that the second end10B of the spring10is stationary.

It can easily be understood that during one rotation of the rotary shaft7A,7B, the position of the pivot5relative to a plane perpendicular to the plane ofFIG. 4and containing the axis of rotation of the rotary shaft7A,7B, varies. Rotation in either direction of the rotary shaft7A,7B enables the pivot5to rise relative toFIG. 4, thereby compressing the closure spring10by raising the plate12on which the spring is placed.

Advantages of the Invention

Thus, the control device of the invention proposes combining in a single rigid element the cam4, the pivot5, the support arm6, and its rachet system, together with the rotary shaft7A,7B. The various mechanical elements used in prior art devices, such as, for example: a transmission chain between the control system and the spring are avoided. This leads to a much smaller risk of failure and to an assembly that is more compact.