CONTROL DEVICE

Abstract: The present invention relates to a control device in which a spring means controls switching means in a switching device. Such a device is used e.g. in connection with load separators or disconnector equipment. In addition to the spring means, the device of the invention comprises a release spring means (4) for returning the switching means to "Open" position in possible malfunction of the switching device or when remote control is used. In the device of the invention, the control shaft charging the release spring (4) is also provided with a release mechanism for releasing the coupling between the manual control and the release spring of the device after the charging is complete.

Description: CONTROL DEVICE The present invention relates to a control device comprising a spring means for controlling switching means, a position indicator shaft for indicating the position of the switching means, a control shaft, arranged in the spring means and surrounding the position indicator shaft, for charging the spring means, and a release spring means for returning the switching means to the previous switching state. Such a device is a substantial part of a switching device, used in internal and external switch plants. Control devices are used to switch a switching device between the "Open" and "Closed" positions. Switching devices mounted on poles have also lately been provided with earthing functions, resulting in extremely high reliability requirements set on the position indication used in the devices. Traditionally, mains systems have been earthed by a procedure completely separate from the pole disconnector with an electrician climbing a de-energized pole in order to fasten the earth wire. The advantage of this is that the electrician and other people working in the area have actually seen the earth wire and have known that the network is earthed. However, the method is quite laborious and requires the presence of an electrician during the mounting and dismounting of the earthing. The (normally) energized conductors of an electric circuit built on pole lines are most commonly earthed by means of a separate, transportable earthing means. The advantage of this is that the earthing means is visible. However, the use of a transportable earthing means is difficult and laborious and requires the presence of an electrician during the mounting and dismounting of the earthing. Consequently, the present trend is towards switching devices earthed by means of an earthing device, such as so-called knives, attached to the switching means, by turning them to the earthing position. The position of the earthing device is then visible even in air-isolated devices. The new SFS6 gas-isolated switching devices make it difficult to catch sight of the switching means, and consequently the position of the switching devices is indicated by means of a position indication mechanically coupled to the switching device. Three-position switching devices provided with a separate operating shaft and, if needed, also a control device for earthing are currently often used in internal switch plants. Similarly, a separate control device and operating shaft is used for the control of "Open" and "Closed" positions. Hazardous use of switching devices is prevented by locks and blocking. Two/three-position control devices provided with one control spring (torsion spring) have lately become commercially available, the positions of these control devices being "Earthed" - "Open" - "Closed". In these control devices, only an intermediary locking in the device distinguishes a two-position control device from a three- position control device. The intermediary locking prevents the switching motion "Open" - "Earth" in the control device. Control devices open and close a switching device by spring force. The advantage of spring force is the opening and closing speed, which is important in the operation of the switching device. The springs used in the device can be pressure springs, draw-springs or torsion springs. Pressure and draw- springs are usually operated by a so-called throw-open mechanism, the spring being pressed or drawn to a given stress state at its dead point. Having passed the dead point, the spring is released and provides thus a rapid and linear control motion. A torsion spring is commonly used because it requires little space. Torsion springs are used in e.g. so-called two-spring control devices in which one spring, a so-called release spring, can be pre-charged for rapid release from e.g. a fuse switch. Load disconnectors provided with such a control device are consequently called fuse load disconnectors. It is extremely important to be able to control these to open when such a switching device is controlled against short-circuit owing to erroneous control. When a control device is released by using a fuse switch or through remote control, the risk is, however, that a manual control lever is also connected to the device. As the release spring is released to perform a switching motion, a rotational motion is simultaneously transmitted to the lever or a similar manual control device, and this may damage people or devices in the vicinity of this manual control device, unless some kind of disconnection is ar- ranged therein. A further problem in known devices is that a second spring (release spring), released by using a fuse switch or in some other way, directly affects the control shaft of the switching means. In this case impaired operation of the release spring causes an imperfect switching motion in the switching device creating various risk situations. The object of the present invention is to eliminate prior art disad- vantages and provide a completely novel solution which prevents manual control devices from operating incorrectly and disturbing operation, and ensures safe operation of a switching device even if the release spring operates defectively. This object is achieved by the control device characterized in the claims of the present invention. To be precise, the device of the present invention is mainly characterized in that the control shaft is arranged to comprise two parts: an outer spline shaft and an inner spline shaft; the parts of the control shaft being interlinked by connecting means arranged in a rotating disc attached to the outer spline shaft and a rotating plate attached to the inner spline shaft, and that the rotational motion of the control shaft is arranged to generate in the rotating disc and the rotating plate a motion in the direction of the control shaft for separating the discs one from the other in order to break the connection between the connecting means. The control arrangement of the control device is also characterized in that the release spring means is arranged to charge the spring means. The invention provides significant advantages. It prevents injuries and equipment damage due to remote or fuse release under uncontrolled circumstances and enables faulty switching against short-circuit without harm to operators or equipment. The invention also ensures that a switching device operates continuously irrespective of the operation of the release spring. It ensures that the transfer motion transmitted to the control shaft is always sufficient to accomplish a perfect switching motion. In addition to the above, it should be noted that all control, disconnection and charging motions take place from around one control shaft. The motions are mere rotational motions except for the axial disconnection motion of the rotating disc, in accordance with the invention. No auxiliary levers or shafts are used in the control device of the invention, resulting in an extremely simple, reliable and inexpensive device structure. It is a primary object of the invention to reduce the number of structural parts and to simplify the functions of the control device. Furthermore, the present control device can easily be modified for different switching devices and the particular switching angles required. This can be effected by the release spring module used in the device by changing the positioning of the wedge surfaces and the locking devices without any major structural changed to the device. The invention is characterized by a principle according to which disconnection during a charging motion is achieved by changing the rotational motion of the transmission surfaces on the periphery of a lifting disc into an axial motion in a lifting plate and a rotating disk. A separate so-called torque disc, including cogs and pressure springs, has been constructed in order for the rotating disc to be able to move in the direction of the longitudinal axis of the device and simultaneously act as a torque transmitter. The use of cogs is not at all substantial, the axial motion may equally well be achieved by one motion surface and one release spring. The motion surface is preferably able to transmit both torque and axial motion. Such a surface could be e.g. a circular surface, ground even, having sides that are cut even and surrounded by a corresponding sleeve or opening. The so-called lifting plate used in the control device of the invention is anchored to the frame of the device. This may be accomplished in different ways, such as by using a separate screw or other supplementary part, an anchor part cast on the lifting plate, or the like. It is essential that by means of the anchoring point the lifting plate is arranged not to rotate in the control device in such a way that the lifting plate is under no circumstances able to rotate to- gether with the charging or disconnection motions occurring in the control device. However, the lifting plate has to be able to move axially. The mechanical fastening of the lifting disc to the position indicator shaft or any other shaft transmitted directly from the control spring can be designed in various ways, such as by a cylindrical cog, a screw, a profile surface, by welding, etc. It is essential that the lifting disc always rotates in the same way as the position indicator shaft. In the following the invention will be described in more detail by means of the attached drawings, in which Figure 1 shows a distribution pattern of the control device according to the invention, Figure 2 is a detail drawing of the equipment components attached to the outer spline shaft shown as a distribution pattern, and Figure 3 is a detail drawing of the equipment components attached to the inner spline shaft shown as a distribution pattern. The Figures show a preferred embodiment of the invention. Such a control device comprises a spring means, known per se, disposed in a control device casing 1. In a switching device (not shown), the spring means controls switching means whose switching state is transmitted to position indication (not shown) by a position indicator shaft 2. The position indicator shaft is surrounded by a control shaft whose rotational motion is used to charge the spring means for generating a fast release and switching in the switching device. In order to achieve a charging motion, an outer end 3 of the control shaft is provided with e.g. a lever or other suitable, preferably manually driven control means. The control shaft may also be motor-driven by e.g. remote control. The same charging motion as is used for charging the spring means to achieve switching, is preferably used to charge a second spring means, i.e. a release spring means 4, in the device. The purpose of such a release spring means is to return the coupling means to "Open" position in case of malfunction. In order to prevent the control shaft rotation caused by the return motion from being transmitted to the manual lever, the control shaft is preferably divided into two parts at the outer end 3 of the shaft, the two parts being an outer spline shaft 5 and an inner spline shaft 6. In order to transmit the charging motion occurring in the control device to the spring means, a torque disc 7 is attached to the outer spline shaft substantially rigidly and arranged to control the rotating disc 8 in such a manner that control cogs 9 extend from the torque disc to receiving openings 10 in the rotating disc. The rotating disc 8, in turn, is attached to a rotating plate 11 , secured non-rotatably to the inner spline shaft 6 through projections 12 disposed in the rotating disc, the projections being arranged in slots 13 disposed in the rotating plate. When the lever is rotated, the rotational motion is consequently transmitted from the outer spline shaft 5 to the torque disc 7 and further to the rotating disc 8 from which it is transmitted via the rotating plate 11 to the inner spline shaft 6 which charges or controls the charging of the spring means. At the same time, a gripping means 14 in the rotating plate 11 is arranged to control the motion of a tightening arm 15, a tightening means 16 arranged in the charging arm being arranged to tighten the release string 4 in the device. As the charging motion and the drawing motion reach their predetermined values, the release spring is locked by a blocking means (not shown) which can be controlled by a fuse device or a relay, manually or by a magnetic controller as the spring means in turn is released and directs the energy charged therein to charging the control spring. Owing to the release of the spring means and the rotation of the switching means, the position indication shaft 2 in the device turns and directs the position indication to a new position. Owing to the release of the spring means in the control device, a lifting disc 17, rigidly attached to the position indicator shaft 2, has turned to a new position simultaneously forcing a lifting disc 18, arranged in the centre of the rotating disc, to an axial motion as at least one transmission surface 19 arranged in the lifting disc hits at least one sliding surface 20 arranged in the lifting plate surface facing the lifting disc. The release mechanism of the control shaft according to the invention is one of the most critical parts of the present invention. The purpose of the lifting parts of the embodiment of the present device is thus to release the coupling between manual control and the release spring when the charging is complete. The transmission and sliding surfaces are thus positioned in such a way that they do not meet until at the end of the control motion in order to minimize friction. The advantage is the ability to utilize the kinetic energy of the spring energy of the initial stage. The wedge surfaces of the transmission and sliding surfaces 19 and 20 are formed to have only an about 30° inclination, and consequently an advantageous power transmission is achieved to the power directed upwards from the rotational power. In addition, the friction of the wedge surfaces can be reduced by advantageous material choices and good surface quality, and possibly by the use of lubricant grease. Another essential function of the invention is provided by the rotating plate 11 : when the control device is being charged from "Open" position to "Closed" position, the rotating plate must rotate with the charging motion since only the rotating plate charges the spring means. The control motion is transmitted from the control means only to the rotating disc 8 from which the motion is further transmitted or is not transmitted to the rotating plate depending on the particular case. After the spring means is released in "Closed" position, the rotating disc 8 is disconnected in such a way that the rotating plate 11 can still move freely back to "Open" position irrespective of the rotating disc. The rotating plate moves with the rotating disc counterclockwise and charges the spring means if the release spring 4 is not released after charging. A coupling takes place again in "Open" position, the motions of the rotating disc 8 in both directions ("Closed" - "Earth") causing a corresponding motion in the rotating plate. The above co-operation between the rotating plate and the rotating disc is implemented in accordance with the following procedural description assuming that the three-position control device is in "Open" position when charging is started. The lever is turned in order to manually control the control shaft towards "Closed" position, the release spring 4 being in an uncharged state (in a two-position version the procedure is otherwise the same, but control is impossible in the "Earth" direction). As the lever is turned clockwise, the torque is transferred via the outer spline shaft 5 from its centre to the grooved torque disc 7. The control clogs 9 in the torque disc transmit the rotational motion further via the receiving openings to the sleeve-like rotating disc 8. The rotat- ing disc comprises the projections 12 which rest in the slots 13 of the rotating plate 11. The projections and slots co-operate to turn the rotating plate around the longitudinal axis of the device. The rotating plate 11 transmits the torque further from its grooved centre via the inner spline shaft 6 to the spring means controller (to the grooved centre of the release disc of the controller device). At the same time the turning motion of the rotating plate is transmitted via e.g. a therein arranged gripping means 14 to a release spring tightening arm 15 and from there further to a tightening means 16 which charges the device as the lever of the tightening means of the release spring is simultaneously locked into its operating position. The release spring 4 is preferably anchored at one end to the frame of the device. The position of the end of the spring can be moved in order to carry out different pre-tightenings. The rotational motion of the tightening means 16 starts to tighten the release spring from its centre. As the rotational motion reaches the point about 1 to 2° before the release of the spring means, the bent lever of the tightening arm 15 is locked into a locking mechanism (not shown in the Figure) provided in the device. As the spring means is being charged, the position indicator shaft and the lifting disc arranged therein remain substantially stationary. At the end of the charging motion the spring means is released inside the control device controlling the switching device and the position indicator shaft preferably 80° clockwise in the present embodiment. The lifting disc 17, and its transmission surface 19, secured to the position indicator shaft 2, rotates by essentially the same angle and at the end of the rotational motion the transmission surfaces hit the corresponding sliding surfaces 20 of the lifting disc 18 disposed above the transmission surfaces. When the rotational motion of the lifting disc is blocked by a locking means 22, extending from the lifting disc to the body of the device via a locking opening 21 arranged on the side of the rotating disc 8, a swift, about 5 mm rise occurs in the lifting disc, the rise being sufficient to lift the rotating disc, and thus the therein arranged projections 12 up from the slots 13 of the rotating plate 11. The rotating plate 11 is physically detached from the rotating disc 8, the release spring carrying it along for substantially the same 1 to 2° which was the difference in locking and release. In other words, the release spring 4 pre-charges the spring means towards "Open" position by said 1 to 2°. The locking stops the release spring and the rotating plate. The rotating disc 8 rises about 5 mm and presses together pressure springs 23 surrounding the control cogs 9 of the torque disc 7. The motion is rendered possible by means of the control cogs of the torque disc, whereby they sink deeper into the receiving openings 10 of the rotating disc inside the rotating disk during the pressing stage. The rotating disc is now completely independent of the operation of the release spring 4 in such a manner that when the release spring is released manually or e.g. by fuse-backup, the rotating plate rotates as the tightening arm 15 of the release spring pushes the gripping means of the rotating plate. The rotating plate now charges the spring means with the rotating disc remaining stationary. The charging ends as the control device is released. Thus the release spring operates expressly as an "Open" spring. While the rotating plate and rotating disc are separated one from the other, the rotational motion of the position indicator shaft or the rotating disc, attached via the inner spline shaft to the control string, caused by the release of the control spring, is not at all transmitted to the outer spline shaft or to the lever attached thereto or to any other control means. This way the control spring can operate freely and a person in the vicinity of the control means will suffer no injuries, particularly when the control spring is released by remote control or when control is made against short-circuit. If the release spring 4 is not released, but remains in a charged state behind locking, the projections 12 of the risen rotating disc 8 will get into contact with upwards bent pegs 24 during a counterclockwise rotation. In this case the charging motion may be finished "manually", the spring means controlling the switching device to "Open" position. The transmission and sliding surfaces then withdraw from their overlapping position and the rotating disc descends owing to the pressure springs 23. The projections of the rotating disc descend into the slots of the rotating plate. After the release spring 4 has been released, the rotating disc 8 can be controlled complete normally counterclockwise as an "empty motion" until its projections get into contact with the upwards bent pegs 24 of the rotating plate. After the release spring has charged the control spring and it has been released and switched the switching device to "Open" position, the transmission and sliding surfaces are withdrawn from an overlapping position as above. However, now the rotating disc is not able to directly descend since the slots of the rotating plate are at "Open" position and the rotating disc is still near "Closed" position. The pressure springs of the rotating disc press the rotating disc against the surface of the rotating plate, but this does not prevent a counterclockwise "empty control motion". As the pressure springs reach the slots, they press the rotating disc in position. Hereafter the control device can be controlled quite normally, either back in "Closed" direction or in "Earth" direction (three-position control device). When controlling in "Earth" direction, no disconnection motion takes place, but the projections of the rotating disc remain normally in their notches. It will be understood that the foregoing description and the related drawings are only intended to illustrate the present invention. The invention is consequently not restricted to the embodiment described in the above and in the claims, but it will be apparent to practitioners skilled in this art that many modifications and variations of the invention are possible within the inventive idea disclosed in the attached claims.

Claims: CLAIMS 1. A control device comprising a spring means for controlling switching means, a position indicator shaft (2) for indicating the position of the switching means, a control shaft, arranged in the spring means and surround- ing the position indicator shaft, for charging the spring means, and a release spring means (4) for returning the switching means to the previous switching state, characterized in that the control shaft is arranged to comprise two parts, an outer spline shaft (5) and an inner spline shaft (6), the parts of the control shaft being interlinked by connecting means (12, 13) arranged in a rotating disc (8) attached to the outer spline shaft and a rotating plate (11) attached to the inner spline shaft, and that the rotational motion of the control shaft is arranged to generate in the rotating disc and the rotating plate a motion in the direction of the control shaft for separating the discs one from the other in order to break the connection between the connecting means. 2. A device as claimed in claim 1, characterized in that the connecting means (12, 13) comprise in the rotating disc at least one projection (12) arranged in at least one slot (13) in the rotating plate. 3. A device as claimed in claim 1 or 2, characterized in that a lifting disc (17) provided with transmission surfaces (19) is arranged in the position indicator shaft (2), near the end facing the rotating disc (8) of the inner spline shaft (6), and during a charging motion of the spring means the lifting disc is in contact with a lifting disc (18) and its sliding surfaces (20) arranged in the rotating disc (8), the transmission surfaces and sliding surfaces being arranged to interconnect during a rotation of the position indicator shaft (2) in order to provide an axial shift in the rotating disc. 4. A device as claimed in claim 3, characterized in that the rotating disc (8) is arranged rotatably relative to the lifting disc (18) to prevent a rotational motion of the lifting disc relative to the frame of the device. 5. A control device comprising a spring means for controlling switching means, a position indicator shaft (2) for indicating the position of the switching means, a control shaft, arranged in the spring means and surrounding the position indicator shaft, for charging the spring means, and a release spring means (4) for returning the switching means to the previous switching state, characterized in that the release spring means (4) is arranged to charge the spring means.

Inventors: LINTUNEN HARRI, LINTUNEN, HARRI
Applicants: ABB TRANSMIT OY, LINTUNEN HARRI, LINTUNEN, HARRI
Application year: 1997
Main classification: H01H9
IPC codes: H01H9