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.
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.
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 spring 22 via a gearwheel 16, an intermediate gearwheel 33, and a primary toothed wheel 5. The closure spring 22 is connected to the primary toothed wheel 5, which is made up of three coaxial gearwheels A, B, and C. The gearwheel B has an outer set of teeth 35 over its entire periphery, whereas the gearwheels A and C are provided with respective sets of teeth 34a and 34b over only respective fractions of a circular arc. While the closure spring is being loaded, the motor 3 drives the toothed wheel 16 in the clockwise direction. It therefore drives the intermediate toothed wheel 33 in the opposite direction. This intermediate toothed wheel 33 meshes with the primary toothed wheel 5. When the closure spring 22 is fully loaded, the toothless section 34 ensures that the intermediate toothed wheel 33 and the toothed wheel 16, together with the motor 3, no longer turn together with the gearwheel A. The toothless section 34 decouples the motor 3 from the gearwheel A and prevents the motor from being damaged as a result of the system being constrained to stop.
A rachet system having pawls 41a, 41b is used on the gearwheel C and co-operates with the inner teeth 36 of the gearwheel B. When the closure spring is fully loaded, the gearwheel C stops turning because of its non-toothed section 34b. Nevertheless, the gearwheel B, driven by the pawls 41a, 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 spring 22 relaxing.
That solution requires at least two gearwheels A and B to be used in combination in order to load the closure spring 22 and to drive the movable contacts of the switch. The gearwheel A is needed because of its non-toothed section 34a that 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 wheel 33, 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.
To this end, the invention mainly provides a spring type control device comprising:
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.
The invention and its various technical characteristics can be better understood on reading the following description that is accompanied by four figures, in which, respectively:
On either side of the assembly constituted by these four elements, there is the rotary shaft of the device in two portions 7A and 7B. These two portions 7A and 7B are coaxial and they are designed to be supported by bearings. The pivot 5 is offset axially from the rotary shaft 7A, 7B.
It can thus be seen that the rotary shaft 7A, 7B, the cam 4, the pivot 5, and the support arm 6 are 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 wheel 1, there can be seen an inner rim 1A extending around the entire circumference of the toothed wheel 1. This enables the wheel to be positioned relative to the arm 6 of overall diameter greater than the inside diameter of the lateral rim 1A.
The pivot 5 serves to connect the unit shown in
A pawl 8 pivotally mounted on one end of a branch 6B of the support arm 6 co-operates with the inner set of teeth 2 of the toothed wheel 1 to form a rachet system. The end of the pawl 8 thus penetrates between two teeth of the inner set of teeth 2 of the toothed wheel 1. When the wheel turns clockwise, the pawl 8 is engaged between two teeth of the inner set of teeth 2 of the toothed wheel 1. Under such circumstances, both portions 7A and 7B of the rotary shaft, the support arm 6, and the cam 4 turn by the same amount in the clockwise direction together with the toothed wheel 1.
In contrast, if the support arm 6 turns clockwise, the pawl 8 tends to disengage from the inner set of teeth 2 of the toothed wheel 1. Thus, the assembly secured to the support arm 6 no longer transmits any mechanical moment or energy to the toothed wheel 1.
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 wheel 1 clockwise 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 teeth 2 of the toothed wheel 1 and all of the elements shown in
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 pivot 5 and 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 pawl 8 disengages from the teeth of the inner set of teeth 2 of the wheel 1. The wheel 1 is therefore not driven in rotation and does not transmit a jolt to the drive motor.
The rachet system operates as follows. The pawl 8 is mounted to pivot at one end of a branch of the support arm 6, by means of a small pivot pin 9. By means of this pivoting connection, the pawl 8 can occupy two positions. In
The pivot 5, which is placed between the cam 4 and the support arm 6, is offset axially relative to the rotary shaft 7A, 7B. It can thus be seen that during a rotation of the rotary shaft 7A and 7B, the position of the pivot 5 relative to an axis perpendicular to the axis of
It can easily be understood that during one rotation of the rotary shaft 7A, 7B, the position of the pivot 5 relative to a plane perpendicular to the plane of
Thus, the control device of the invention proposes combining in a single rigid element the cam 4, the pivot 5, the support arm 6, and its rachet system, together with the rotary shaft 7A, 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.
Number | Date | Country | Kind |
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12 61348 | Nov 2012 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/074876 | 11/27/2013 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2014/083064 | 6/5/2014 | WO | A |
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Entry |
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International Search Report and Written Opinion for PCT Application No. PCT/EP2013/074876 mailing date Jan. 8, 2014. |
Preliminary French Search Report for FR Application No. FR12 61348 dated Apr. 6, 2013. |
Number | Date | Country | |
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20150325386 A1 | Nov 2015 | US |