MXPA96006693A - Conmuta actuator - Google Patents

Abstract

The present invention relates to an actuator for a high-voltage switch characterized in that it comprises: a) an impeller frame defining a bell crank pivot axis and an oscillator pivot shaft parallel to the bell crank pivot axis , but spaced in a backward direction from it, b) a bell crank mounted on the frame for a pivot movement about the bell crank pivot axis, the bell crank element has an opening side fitting and an attachment of the closing side, the bell crank being pivotable between an open position and a closed position, c) an oscillator mounted to the frame for a pivoting movement about said oscillating pivot axis, the oscillator has a point of clamping of the opening side, the oscillator being pivotable between a fully closed position and a fully open position, d) a spring on the opening side connects between the fastening points of the opening side of said oscillator and said bell crank, and a spring of the closing side connected between the fastening points of the closing side of said oscillator and of said bell crank so that the The spring on the opening side will deform and the energy will be stored therein with the movement of the oscillator from its fully closed position to its fully open position, while the bell crank remains in its closed position and so that the spring on the closing side will be deformed and the energy will be stored there with the movement of the oscillator from its fully open position to its fully closed position, while the bell crank remains in its open position e) a trap on the opening side to restrict said bell crank against the pivot movement opening when said bell crank is in a closed position thereof and a closing-side trap for restricting said bell crank against closing pivot movement when said bell crank is in said open position thereof; f) the trap release means for disengaging said trap from the opening side when said The oscillator reaches a position without opening latch near the fully open position during the opening movement thereof and disengaging said trap from the closing side when said oscillator reaches a position without closing latch near the fully closed position during the movement of the latch. closure of the same, g) mounting means for connecting said frame of a body of a high-voltage switch and connecting said bell crank to an actuating element of the switch, whereby when the oscillator pivots in closing movement, said spring on the closing side will deform until the oscillator reaches the position without closing latch, where The spring on the closing side will urge the bell crank in a pivoting movement towards its closed position and urge the actuating element of the switch rapidly towards a closed position thereof and when the oscillator pivots in an opening movement said spring on the opening side is It will deform until the oscillator reaches the position without opening latch, so that the spring on the opening side will push the bell crank in the pivoting movement towards its open position and push the actuating element of the switch rapidly towards a closed position of the same.

Description

SWITCH ACTUATOR This invention relates generally to actuators for switches used in electric power systems.

Background of the Invention High voltage switching assemblies with vacuum or subatmospheric circuit breakers for electrical power circuits and systems are well known in the art, such as shown in U.S. Patent Nos. 4,568,804; 3,955,167 and 3,471,669. Encapsulated vacuum type switches or circuit breakers are also known, as shown in U.S. Patent Nos. 3,812,314 and 2,870,298.

In such switch and circuit breaker assemblies, a pair of coacting contacts, one fixed and the other mobile, are provided to control and interrupt the flow of current. The contacts are provided in a controlled atmosphere contact assembly which also includes a relatively fragile glass or ceramic case, commonly referred to as "bottles". The contacts can be housed inside the bottle. A metal bellows is typically provided on one end of the bottle, and the movable contact is bonded to the interior of the bellows. An operating rod attached to the outside of the bellows can be moved so as to move the moving contact within the bottle. The interior of the bottle is maintained under a controlled atmosphere, such as air or other gas under a low subatmospheric pressure, to protect the contacts from damage caused by arcing when the contacts are open and closed. The glass or ceramic wall of the bottle provides a permeation resistant cover which maintains the atmosphere controlled by the life of the device. Even when such a controlled atmosphere is employed, however, the contacts must move towards each other and separate quickly to minimize arcing.

The actuators used to provide such rapid movement must meet various demand requirements. The actuator must move the mobile contact of the switch in a repeatable and predictable manner, with sufficient force to overcome the friction and inertia and with sufficient force to close the contacts securely. However, the range of movement of the actuator must be limited and predicted, so that the actuator does not damage the other components of the switch. A high-voltage switch in an electrical installation system can remain open or closed for many years. Therefore, the actuators must operate reliably when activated by a worker even after they have been left without work for years. The actuator must also be able to withstand exposure to extreme temperatures, water and environmental contaminants. This must support a repeated operation. The actuator must also be manufactured at a reasonable cost. This should also be compact and compatible with the boxes used by other elements - the switch. These last mentioned features are particularly important in actuators intended for underground distribution applications.

The patent in the United States of North America No. 3,471,669 seeks to provide such a switch for underground applications. The switch according to the patent 3,471,669 includes a vacuum or subatmospheric controlled atmosphere controlled contact assembly. The contact assembly for the coacting contacts has rods reinforced and spaced around the outside and is encapsulated directly in a waterproof elastic cover generally covered by an electrically conductive coating to ground. A spring acting spring and a lever assembly are placed inside the cover and linked to the contact rod of the contact assembly. A rotating shaft of a dielectric material extends from the outside of the cover to the lever assembly. The rotation of the shaft drives the spring and the lever to move the contacts and close or open the circuit. Nevertheless, the switch described in the '347 patent has not been widely adopted in the art. As reported in the article by Odom and others, Development and Testing of the Encapsulated Vacuum Sectional Switch for Underground Distribution (IEEE Publication, date unknown), elastomers which are vulcanized under heat and pressure can not be easily used for training of the box in the switch and manufacturing process design as shown in U.S. Patent No. 3,471,669.

Certain elastomers vulcanized by heat and pressure are insulating materials especially useful for underground electrical power systems. Elastomers such as EPDM (ethylene propylene diene monomer) combine high dielectric strength with excellent resistance to the effects of ozone and corona discharge and other useful properties. Molded and vulcanized elastomers under heat and pressure, such as EPDM, have been almost universally adopted as building materials for boxes used in other underground electrical distribution systems.

The commonly assigned and co-pending application of the United States of North America by Glenn J. Luzzi entitled High Voltage Switches, filed on this same date (the Luzzi application) by description is incorporated herein by reference provides an encapsulated switch for use in a circuit high voltage. The switches according to the preferred embodiments of the Luzzi application include a box made of an elastomeric material, a preferably tubular and hollow dielectric reinforcing element placed in the box and in intimate contact with the elastomeric material of the box and a set of contact including a bottle having the fixed and movable contacts there placed- in the hollow reinforcement element. The switch may also include a filler material, different from the elastomeric material of the box, between the bottle and hollow reinforcement element. The reinforcing element and the filler material effectively insulate the fragile contact assembly from the conditions found in the molding of the box, while still providing a dielectric structure free of voids.

A switch according to the preferred embodiments of the Luzzi application includes an actuating element accessible from the outside of the box and linked to the mobile contact. Therefore, the box can include a flexible diaphragm with the actuator element extending therethrough. The switch may further include an impeller or actuator for forcibly moving the actuating element.

Synthesis of the Invention One aspect of the present invention provides an actuator suitable for use with high voltage switches, including those taught in Luzzi's application and others. An actuator according to this aspect of the present invention includes a drive frame defining a bell crank pivot axis and an oscillating pivot shaft parallel to the bell crank pivot axis but spaced in a rearward direction therefrom. A bell crank is mounted on the frame for pivotal movement about the bell crank pivot axis between an open position and a closed position. The bell crank has a point of attachment of the opening side and a clamping point of the closing side, an oscillator is mounted on the frame for a pivoting movement about the pivot axis oscillator, between a fully open position and a position completely closed, the oscillator having a point of attachment of the opening side and a clamping point of the closing side.

A spring on the opening side is connected between the clamping points on the opening side of the oscillator and the bell crank, and the spring on the closing side is connected between the clamping points on the closing side of the oscillator and the crank. Bell. The attachment or attachment points are arranged so that the spring on the side of the opening will deform to a stressed condition when the oscillator is moved to its fully open position while the bell crank remains in its closed position, while the The spring on the closure side will deform to a stressed condition when the oscillator is moved to its fully closed condition with the bell handle remaining in the open position.

An opening-side trap is provided to restrain the bell crank against opening pivot movement when the bell crank is in its closed position, and a trap on the closing side restricts the bell crank against the closing pivot movement when the bell crank is in its open position therefrom. The actuator further includes the trap release means for disengaging the trap from the opening side when the oscillator reaches a position without opening latch close to its fully open position during the opening movement thereof and for disengaging the trap from the closing side. when the oscillator reaches a position without closing latch close to the full closing position during the closing movement thereof.

The actuator may further include mounting means for connecting the frame to a body of the high voltage switch and connecting the bell handle to a switch actuator element. The user operates the switch by pivoting the oscillator. When the oscillator pivots in the closed movement the spring on the closing side will deform, and the energy will be stored therein until the oscillator reaches the position without closing latch, and the trap on the closing side is disengaged. At this time, the spring on the closing side will urge the bell crank in a pivotal movement towards its closed position and urge the switch actuator element rapidly towards a closed position thereof. When the oscillator pivots in an opening movement, the spring on the opening side will deform, and the energy will be stored therein until the oscillator reaches the position without opening latch, whereby the trap on the opening side is disengaged, and the spring on the opening side urges the bell handle in a pivotal movement towards its open position, thereby urging the actuator element of the switch rapidly towards a closing position thereof. During the opening and closing operations, the inertia of the components, and particularly the inertia of the bell crank helps to limit the speed of the mechanism. Therefore, the spring can be powerful enough to overcome any junction in the actuator itself or in the commutator, thus ensuring reliable operation without causing the mechanism to reach destructive speeds if such a connection occurs to us. The inertia of the components helps to distribute the stored energy of the springs on the complete opening and closing movement. During the beginning part of each closing opening movement, the spring driving movement will only be beginning to relax from its completely deformed condition and will therefore provide the maximum driving force. As the movement continues, the spring energy is converted to kinetic energy of the moving components. In the last portion of the blow, the spring is partially relaxed and therefore provides a lower driving force. However, the kinetic energy stored in the moving components helps to propel the movement during this last portion of the blow. This allows reliable operation with smaller springs than would otherwise be necessary, and therefore helps to make the mechanism compact.

Desirably the components are arranged so that the spring on the side of the opening does not relax completely during the movement of the bell crank to its open position, while the spring on the closing side does not relax completely during the movement of the crank. from bell to its closed position. Therefore, one of the springs continues to drive the bell crank in an opening or closing movement until the end of the movement; The bell crank and other components connected to it do not require navigating through any part of its movement. This helps ensure that the mechanism will not get stuck before the end of the movement.

More preferably, the attachment point of the opening side of the bell crank and the oscillator are positioned on one side of the plane defined by a bell crank pivot shaft and the oscillator pivot shaft, referred to as the opening side. of the plane, while the clamping points of the closing side of the bell crank and the oscillator are placed on the opposite closing side of the plane. The clamping point of the opening side of the bell crank moves backwards during the opening movement of the bell crank, while the clamping point of the closing side moves backwards during the closing movement of the crank. of bell. The clamping point of the closing side of the oscillator moves backwards during the pivoting movement towards the full closed position, while the attachment point of the opening side moves backwards during the pivoting movement of the oscillator towards the complete closed position. Therefore, the springs of the closing side and of the opening side can be tension springs, such as the massive spiral springs. When the oscillator is moved while the bell crank is restrained by one of the traps, one of the springs will be stretched and the other spring will relax.

More preferably, the bell crank includes a pair of elements spaced apart from one another and the oscillator includes a pair of elements spaced apart from one another in the directions parallel to the pivot axes.

The elements of the bell crank and the oscillator cooperatively define a channel on the closing side on the closing side of the plane and a channel on the opening side on the opening side of the plane. The springs are received in the channels. This arrangement provides a particularly compact assembly. In addition, the elements of the oscillator and the bell handle guide and constrict the springs during the rapid movement of the bell crank.

It is particularly desirable to guide and constrict each spring when the spring is loose. That is, the spring on the opening side must be guided during the closing movement of the bell handle driven by the spring on the closing side and vice versa. The elements of the bell crank and the oscillator will integrate with one another to form virtually continuous walls joining the channel of the opening side when the oscillator is in the closed unlatched position and the oscillator is in the open position thereof, and as to form virtually continuous walls by joining the channel of the closing side when the oscillator is in the position without opening latch and the bell crank is in the closed position thereof. Therefore, the continuous walls will constrict the opening spring during the closing movement of the bell handle and will restrain the closing spring during the opening movement of the bell handle.

The mounting means desirably includes the non-uniform articulation means for linking the bell crank to the actuating element of the switch, to provide a non-uniform rate between the movement of the actuating element and the movement of the bell crank. Desirably, each increase in bell movement produces a relatively small movement of the actuator element when the bell crank is adjacent to its closed position and produces a relatively large movement of the actuator element when the bell crank is adjacent to its closed position. This allows the bell crank to seat the switch movement contact with a reasonable closing speed to minimize impact, but with a high force to ensure closure. The non-uniform articulation means may include a plurality of links connected to each other, to the bell crank and to the frame, so that the bell crank, the frame and the links cooperatively constitute a four-bar link.

Other advantages and objects of this invention will be better understood by those skilled in the art with reference to the accompanying drawings taken with the description that follows and in which: Brief Description of the Drawings Figure 1 is a fragmentary sectional view showing a part of a switch.

Figure 2 is a schematic fragmentary plan view showing an actuator according to one embodiment of the invention in assembly with the switch of Figure 1, the portions of the actuator being removed for clarity of illustration.

Figure 3 is a schematic elevated view of the actuator illustrated in Figure 2.

Figures 4 to 6 are views similar to that of Figure 3, but showing the actuator in different operating positions.

Detailed Description of the Preferred Modalities The switch shown in Figure 1 is a high voltage switch as described in the aforementioned Luzzi application. The structure of the switch itself is not part of the present invention; as stated here only to complete. As used in this description with reference to the apparatus, the term "high voltage" means an apparatus which is adapted to operate at a rated voltage system above 3kv. Therefore the term "high voltage" includes equipment suitable for use in an electrical installation service, such as in systems operating at nominal voltages of around 3kv to around 38 kv, commonly referred to as "distribution" systems, as well as equipment for use in "transmission" systems, operating at nominal voltages above about 38 kv . The commutator includes a box 10 formed of a dialectic elastomer, which is vulcanized under heat and pressure, such as an ethylene propylene monomer diene elastomer (EPDM). The box defines an elongated hole 12 extending in end-direction directions parallel to an axis 14. The box has a fixed end 16 and a second opposite end 18, mentioned here as the operator end. For the reasons discussed below, the direction parallel to the axis 14 along the fixed end 16 is referred to herein as the direction in the closing end direction, while the direction in the opposite end direction, towards the operating end 18. it is mentioned as the direction in the direction of opening end. The box defines a tapered sleeve 20 at the fixed end and an additional tapered sleeve 22 extending perpendicular to the shaft in the end direction. The sleeve 22 has a tubular metal current carrying member that extends through the sleeve 22 to the hole 12 in a direction perpendicular to the axis 14. The part of the box 10 placed between the tapered sleeve 20 and the operator end 18 has a cylindrical outer surface, so that the wall of the box in that region is generally in the shape of a cylindrical tube.

The box 10 further includes a diaphragm 26 integrally formed with other parts of the box. The diaphragm 26 has a peripheral part joining the tubular wall of the box, a central part 30 adjacent to the axis 14 of the box and the annular convolutions 28 between the peripheral and central part. Therefore, even when the peripheral part of the diaphragm is fixed to the box wall, the central part 30 is free to move in relation to the rest of the box with the flexing of the convolutions 28.

The diaphragm 26 is thick enough to provide a full voltage support capability, ie the diaphragm thickness is selected so that the diaphragm will withstand the maximum voltage to be imposed between the current carrying elements of the switch and the ground during the service or during the fault conditions. For example, in a switch designed to operate at a nominal 25KV from phase to phase, the diaphragm and other parts intended to provide full voltage support capability must be capable of supporting at least about 14.4 KV continuously.

The box is provided with an electrically conductive insert 32 formed of a mixture of the same elastomer used for the rest of the box and an electrically conductive material such as carbon black. The insert 32 covers the inner wall of the hole 12 from the diaphragm 26 to a point beyond the hole -24. The insert 32 further extends radially inwardly for a short distance along the interior surface of the diaphragm 26. The insert also has a short tubular section 33 extending along the exterior of the current carrying member 58.

A rigid tubular reinforcing element 36 extends virtually to the full length of the box 10 and an orifice 12. The reinforcing element 36 is formed of a dielectric material having a high physical strength such as polymer thermosetting reinforced with fiber, thermoplastic polymers reinforced with fiber , and high strength polymers. Among the materials which can be used are epoxy reinforced with glass fiber; polyamides, polyvinyl chloride and ultra high molecular weight polyethylene. The reinforcing element is provided with an annular shoulder 38 facing the fixed end 16. The shoulder 38 is facing the direction of closing end direction toward the fixed end 16. The reinforcing element 36 protrudes slightly beyond the tip of the conical part 20 at the fixed end 16. The reinforcing element is provided with the internal threads 40 at the fixed end of the device. The reinforcing element has a hole 37 aligned with the hole of the sleeve 24.

A tubular outer support member 42 lies closely on the outer surface of the box 10 in the regions of the adjacent box toward the operator end 10. The outer support further extends into the opening in a direction in the direction of an end beyond the operator end 18 of the box. The outer support element 42 is formed of an electrically conductive and rigid material such as stainless steel or other metal. The sleeve 22 extends between the box through a hole 46 in the outer support.

The outer support 42 is in an intimate free contact with the outside of the box 10, and is surely joined to the dielectric elastomer of the box. Similarly, the semiconductor liner 32 is intimately bonded to the dielectric elastomer. The reinforcement element 36 is in an intimate gap-free contact with the insert 32 over the part of its length, adjacent to the operator ends 18 and with the dielectric elastomer of the box over the rest of its length.

These components are manufactured by insert molding. Therefore, the reinforcing element 36 is placed on an internal mandrel commonly referred to as a core. The core and the reinforcing element they are placed inside a mold cavity. The core has a face with grooves corresponding to the convolutions 28. An additional core extends through the hole 37 in the reinforcing element. A mixture of elastomer and carbons is injected into the mold around the reinforcing element and core and forges under heat and pressure to form the insert. The assembly is then transferred to a different mold having the shape of the box 10. The element of outer support is also arranged inside the mold, so that the insert, the reinforcing element and the core contained therein are placed inside the outer support element. The current carrying member 58 is also placed in the mold. The dielectric elastomer is then injected into the mold around the reinforcing element and the insert, and into the outer support member 42. The elastomer is maintained under heat and pressure by using the conditions normally employed for the location of the EPDM. To promote bonding, the inner surface of the outer support member 42, and the outer surface of the reinforcing element 36, can be treated with conventional adhesion promoting agents. The molding process forms a permanent gap-free assembly of the support element, the insert, the dielectric elastomer case and the outer support element. The subset is then assembled with the other components discussed below.

The switch further includes an operator end reinforcement 46. The operator end reinforcement is formed of a metallic electrically conductive material, preferably of copper or of a copper alloy. The operator end reinforcement has a first face 48 facing the operating end of the device and in contact with the shoulder 38 of the reinforcing element. The operator end reinforcement also has a second face 50 facing the fixed end 16. A hole 52 extends through the operator end reinforcement and is virtually coaxial with the shaft 14 of the box and the reinforcing element. The hole 52 has an enlarged section 54. The operator end reinforcement also has a threaded fitting 56. A pin 57 is placed within the current carrying member 58 and contacts the threaded fitting 56. As discussed further below, the reinforcement End of operator serves as a terminal for the passage of current through the commutator. The pin 57 serves to maintain the electrical continuity between the current carrying member 58 and the reinforcement 56.

A contact assembly 60 is positioned between the operator end reinforcement 46 and the fixed end 16 of the device. The contact assembly 60 includes a tubular ceramic bottle 62 with a metal fixed end cover 64 positioned at one end of the bottle and an additional operator end cover 66 positioned at the opposite operator end of the bottle. The operator end cover 66 includes an extendable and flexible metal bellows. A fixed contact 68 is mounted on the fixed end cover 64 and projects into the bottle 62, while a stationary operator end contact is mounted on the bellows of the operator end cover 66. The assembly further includes an element rod type operator 72 positioned on the outside of the bellows 66, which forms an extension of the movable contact. Similarly, a threaded fixed end stub contact 74 is formed integrally with the fixed end contact 68 and projects outwardly beyond the fixed end cover 64. The contact assembly 60 further includes a metal shield 76 which it surrounds part of the contacts, the shield being supported within the box by a metal frame 78 that extends through the bottle 62. For this purpose the bottle 62 can be formed into sections, and both sections can be attached to the metal frame. The bottle 62 is hermetically sealed. Therefore, the gasket between the end covers, the contacts and the bottle are gas-proof.

The interior space inside the bottle 62, surrounding the contacts has a controlled atmosphere there. As used in this description, the term "controlled atmosphere" means an atmosphere other than air at a normal atmospheric pressure. More preferably, the atmosphere inside the bottle 62 is under a subatmospheric pressure. The composition of the atmosphere may also differ from normal air. Gases from arc suppressors such as SF6 may be present inside the bottle. The complete contact assembly 60 can be a conventional controlled atmosphere contact assembly of the commercially available type from many sources. Such a contact set is available from the designation L-35590 of the Cutler Hammer Company of Horseheads, New York.

The outer diameter of the bottle 62 is slightly smaller than the inner diameter of the reinforcing element 36 so that there is an annular space between the exterior of the bottle and the interior of the reinforcing element. This annular space is completely filled with a filling and electrical material 80, so as to provide a gap-free interface virtually between the exterior of the bottle and the interior of the reinforcing element. The filler 80 is formed of a dielectric material different from the dielectric material of the box 10. More preferably the dielectric filler 80 is a material which can be placed and brought to its final form without the application of extreme temperatures or pressures. In a service, the dielectric filler is not exposed to a substantial mechanical stress. Therefore, the filler can be virtually selected without regard to its ability to withstand mechanical stress, abrasion and the like. The filler must have a good dielectric strength. Preferred fillers include fats such as petroleum based and silicone based fats, gels such as silicone gels and settable elastomers of the type commonly referred to as vulcanization elastomers at room temperature or "RTV". The compatibility between the filler and the rubber of the box 10 must also be considered. Petroleum-based materials tend to swell the EDPM. Therefore, if a petroleum-based filler with an EPDM box is used, the filler should be isolated from the box during service. The dielectric reinforcing element can provide such insulation. Similarly, a silicone-based filler will tend to inflate the silicone rubber. The filler can also be made by deliberately inflating a rubber or other polymer. Thus the space between the outside of the bottle 62 and the interior of the reinforcing element 36 can be packaged loose with an inflatable polymer, such as EPDM or silicone rubber. The loose pack can be provided as a tube or solid mass; as granules or pellets; or in any other form such as foam or sponge. A liquid capable of inflating the particular polymer used, such as mineral oil (petroleum oil) in the case of EPDM or silicone oil in the case of silicone rubber, is then introduced into the space. The liquid causes the polymer to swell and fill the entire space, thereby providing a void-free interface. This technique can be applied to gaps in other electrical assemblies as well.

A metal fixed end brace 82 is engaged with the threads 40 of the stiffening element 36 and is engaged with the fixed end cover 64 of the contact assembly. The fixed end reinforcement has a central hole receiving the butt contact 74. The additional holes 86 are also provided in the fixed end reinforcement for use during the assembly process as described below. The fixed end reinforcement forces the bottle 62 in the direction of the opening, towards the operator end 18, and holds the operator end of the bottle, as well as the periphery of the end cover to operator 66 in firm contact with the second end face 50 of fixed end 46. Therefore, bottle 62 is kept under compression. A second metal terminal 88 is attached to the butt end 74 and thus to the fixed end 68 of the contact. The switch further includes a fixed end cover 90 formed of an elastomer and a fixed end electrical voltage relief element 92 formed of a semiconductor elastomer. The fixed end cover 90 is placed on the box 10 so that an internal contactor in the fixed end cover is firmly engaged with the conical seat 20 at the fixed end of the box and so that the electrical tension release element of fixed end surrounds the second terminal 88, the butt end 74, the fixed stiffening end 40 and the fixed end cover 64 of the contact assembly. The fixed end cover has a second tubular metal current carrying member 94 mounted therein. A bolt 95 placed on the current carrying member is threadedly engaged with the second terminal 88.

A link 98 is slidably received in the hole 52 of the operator end reinforcement 46. The link 98 is threadedly engaged with the operator member 72 of the contact assembly, and the threaded connection is fixed against movement during service as by a pin (not shown) extending through the threaded contact elements. An annular contact 100 of the type commonly referred to as a "blind" contact surrounds the joint 98. The contact 100 has the projections on its inner and outer surface. The flexible projections on the contact 100 rest on the reinforcement 46 and on the articulation, thus establishing a sliding electrical connection between the reinforcement and the articulation. Thus, the mobile contact 70 of the contact assembly is electrically connected to the first terminal or reinforcement 46. Alternatively, an electrical metal strip such as a copper strip may be connected between link 98 and the first end reinforcement or the first terminal 46. A yoke 102 is slidably engaged with the link 98. A spiral compression spring 104 is positioned between the yoke 102 and the end of the hinge 98, so that the movement of the yoke in the closing direction towards the fixed end 16 to the right in figure 1 will be transmitted to the joint 98 and therefore the mobile contact 70 by a spring.

A bolt 106 is engaged with the hinge and the yoke so that the movement in the yoke in the opposite direction (to the length of Fig. 1) will be transmitted to the hinge 98 and the movable contact 70 through the bolt 106. Bolt 106 desirably applies a preload to the spring 104 so that the spring remains in compression at all times.

An actuating element 108 formed of a strong rigid dielectric material such as an epoxy reinforced glass fiber extends through the diaphragm 26 at the center 30 thereof. The actuating element 108 is fixedly fastened and attached to the center of the diaphragm 30. Preferably, the actuating element 108 can be molded into an insert within the diaphragm by placing the actuator element in the mold when the diaphragm is formed during the insert molding process. mentioned above with a chemical bonding agent on the surface of the actuator element. Chemical bonding agents are well known in the art of rubber molding. A suitable chemical bonding agent is sold under the trademark Chemlok 205. The actuating element itself and the joint between the actuating element and the diaphragm must have full voltage support capabilities.

Alternatively, the actuating element can be assembled to the diaphragm. This can be achieved by molding the diaphragm with a hole more glued than the diameter of the actuating element and then pressurizing the actuating element into the hole so as to form an intimate connection between the surface of the actuating element and the surrounding parts of the diaphragm. The actuating element may be provided with a shoulder on one side of the diaphragm and the fastener such as a nuts and a washer on the other side of the diaphragm. The bra and the shoulder maintain the central part of the diaphragm in compression and keep the actuating element in a fixed position in relation to the diaphragm. Such a compression joint establishes a secure and fixed interface between the actuating element and the diaphragm.

Actuating element 108 is connected to a yoke 102 by a self-engaging connection. Thus yoke 102 has a hole in the end of the yoke closest to the operator end of the device and a slot 110 in the wall of such an orifice. The actuating element 108 has a circumferential groove 112, extending around it. An elastic bump ring 114 is engaged in these grooves so as to connect the actuating element to the link for movement therewith in the directions in the direction of the end.

An actuator or drive assembly 120 according to one embodiment of the present invention is attached to other elements of the switch. The actuator 120 includes an impeller frame 122 mounted on the switch housing 10, a mobile element 124 connected to the actuating element 108 and a mechanism 126 for moving the movable element in the opening and closing directions to move the actuating element and therefore moving the mobile contact 70 (figure 1), thus opening and closing the switch.

The impeller frame 124 may be formed of stainless steel or other suitable corrosion resistant metal or other material. The drive frame has an annular ring 128 formed at a leading end and an additional ring 129. The ring 128 is dimensioned such that it fits within the outer tubular support member 42 (Fig. 1). The machine screws 130 support the collar 128 and therefore the drive frame 122 in an assembled position in relation to the external support element and in relation to the elastomecaries box. An additional cylindrical case 131 (FIG. 2) fits over the ring 129 and covers the impeller mechanism. Only small parts of the box 131 are shown in Figure 2; the rest is removed for clarity and illustration. In addition, cover 131 is omitted on pages 3-6.

The drive frame 122 and the ring 128 are disposed on one side of the operator end 18 of the case 10. The outer end of the actuating element 108 extends through the ring assembly 128 inside the drive frame 122, where the actuating element is located. connected to the movable member 124 of the drive assembly by an adjustable connection such as a threaded connection, provided with a bolt or other suitable closing device to close the adjustment.

The drive frame 122 includes a pair of plates 130 and 132 (figure 2). A pair of bell crank elements 134a and 133b is mounted on a bell crank shaft 138 extending between the plates 130, so that the bell crank elements are pivotable relative to the frame around a bell crank shaft. coincident with the date 138. The bell crank elements 138 are rigidly connected to one another by a plate 139 extending therebetween. An opening side bolt 135 and a side locking bolt 137 extend between the bell crank elements 134 adjacent the front end of the mechanism on the opposite sides. As discussed further below, bolts 135 and 137 form the attachment points for the bell crank connection spring. As best seen in Figures 3-7, each bell crank element has a generally arcuate surface with a notch 140 therein.

An operator shaft 142 extends through the plates 130 and 132 in the bearings (not shown) so that the operator shaft is rotated with respect to the drive frame. The operating shaft 142 has a polygonal head 144 on one end for contact by an operating handle 145. A pair of cam plates 146 are fixedly mounted to the shaft 142. The cam plates 146 cooperatively constitute an oscillator. The oscillator is mounted by an axis 142 for a pivoting movement with respect to the frame 122 about an oscillating axis coincident with the arrow 142. The oscillating shaft 142 is positioned rearwardly of the bell crank shaft 138 but parallel thereto, so that the axes define comparatively a common plane coincident with the central axis 14 of the switch. For convenience of reference, the region on one side of this plane (above the plane and above the axis 14 in each of the figures 2-6) is mentioned as lying on the opposite side of the plane, while the region on the side opposite, below the plane and axis 14 as shown in Figures 2-6, it is said to lie on the plane closing side.

Each cam plate of the oscillator has a pair of main projections 148 and 150 (Figure 4), extending in the forward direction, towards the ring 128 and a pair of trap surfaces 152 and 154 (Figures 3 and 4) extending into the backward direction. As best seen in Figures 2 and 3, the opening side projections 148 of the cam plates 146 extend between the bell crank elements 134 when the mechanisms are in the closed position illustrated in Figures 2 and 3. Lateral closing projections 150 similarly extend between the bell crank elements when the mechanism is in the open position illustrated in Figure 5. A lateral opening bolt or holding point 153, extends between the cam plates 146 of the oscillator about him . opening opening of the common plane 14, adjacent to the lateral projections of the opening of the plates .- A lateral closing bolt or fixing points 155 extends between the cam plates of the oscillator 146 on one side of the lateral closing projections 150.

An opening side main spring 156 extends between the opening side bolt 135 of the bell cranks and the opening side bolt 153 of the cam 146. As best seen in Figure 2, the opening side spring 156 is a powerful and large spring which occupies virtually the space between the bell crank elements and the space between the projections of the cam plates. Also, the spring circuits 156 which engage with the bolts have interior dimensions considerably greater than those of the bolts themselves. A lateral closing side spring extends between the lateral closing bolt 154, the lateral closing bolt 155 of the cam 146 and the lateral closing bolt 137 of the bell crank. Even though the closing spring 158 is shown only schematically in Figures 3-6, it should be noted that the closing side spring is also a powerful and massive spring that occupies much of the space between the bell crank elements and the lateral projections Closing 150 of the cam plates.

A pair of guide link plates 160 are pivotally mounted to the drive frame on one side of the plates 130 and 132 on the pins 162 (Figures 3 and 4). A pair of drive plates 166 extend to one side of the frame plates 130 and 132. A main pin 168 connects the guide link plates 162 to the drive link plates 166 and also connects the link plates 124 of the link. drive mechanism. The drive link plates 166 are connected by additional pins 171 to the bell elements.

The impeller frame 122, the guide links 162, the drive links 166 and the bell crank elements 134 constitute a type of mechanism of the type referred to as a "four bar" linkage.

An aperture trap 170 (FIGS. 3 and 4) is rotatably mounted on the operator shaft 142. The aperture trap 170 is positioned in a space 173 on one side of the cam plate 146 and a bell crank plate 146b on a side of the mechanism. The trap 172 is omitted for clarity of illustration in Figure 2 and Figures 5 and 6. The trap of the opening 170 has a tip equipped with a roller 174. The opening trap 170 also has a finger 176 and a spring mount 178. A trap spring 182 is engaged between the spring mount 168 and the cover 129 of the drive frame. The spring 182 pushes the opening trap 170 in the left to right direction as seen in FIGS. 3 and 4 and thus pushes the tip 174 of the trap to make contact with the arcuate surface of the bell crank element 134b .

A similar closing trap 186 (FIGS. 5 and 6) is rotatably mounted on the operating shaft 142 in the space 188 (FIG. 2) to one side of the crank element 134a. Closing trap 136 is omitted for clarity of illustration in Figure 2 and Figures 3 and 4. Closing trap 186 has a tip equipped with roller 190, a spring arm 192 and a finger 194 similar to the corresponding elements of the opening trap. The trap spring 196 is engaged between the spring arm 192 of the closure trap and the trap 129 of the frame to push the closure trap in the right-to-left direction about the axis 142 and thereby push the tip 190 to make contact with the bell crank plate 134a. The fin plate 196 has a pair of projections 198 a and 198 b (FIG. 2) is pivotally mounted on the impeller frame on an intermediate shaft 200 extending between the frame plate 130 and 132. The pivoting movement of the plate is limited by the stops 202 (figures 3-6). The axes 200 are parallel and comparable with the axes 138 and 142, and therefore with the crank bell and pivot axes.

In operation, the switch is connected in the circuit through the current carrying elements 58 and 94 and therefore through the terminals 46 and 88. The insert 32 is electrically connected to the first terminal 46. Therefore, the insert is kept in the same electrical potential as the first terminal or reinforcement 46. The link 98 and the yoke 102 are at the same potential, and therefore there is no potential gradient within the space incubated by the insert 32. The strain relief element 92 similarly keeps all the components at the fixed end of the switch at the potential of the second terminal 88.

In the position illustrated in Figures 1-3, the switch is closed. The pins 171 are positioned on the shaft 14 in alignment with the bell crank shaft 138 and the pin 168. The tip of the trap opening is engaged in the slot 140 of the bell crank element 138b. The cam or oscillator plates 146 lie in their full closed position. To open the switch, the operator engages the handle 145 (figure 2) and turns the handle to pivot the oscillator or the cam plates 146 from right to left as seen in figures 3 and 4. When the operator turns the oscillator , the bolt or attachment point of the opening side 153 of the bell handle moves in the backward direction, while the bolt or fastening point of the closing side 155 moves in the forward direction. The bell crank 134 is retained in position by the trap 174. Thus, the opening spring 156 is stretched between the bolts 153 and 135 whereby the closing spring 158 relaxed. With a continuous movement of the oscillator, the mechanism reaches the position without opening latch illustrated in figure 4. In this position, the projections of the closing side 150 of the cam plates are engaged between the bell crank elements 134. both the cam plates and the bell crank elements form a virtually continuous channel, with the walls joining the closing spring 158 on opposite sides thereof.

As the oscillator 146 is moved from the fully closed position of figure 3 to the position without opening latch of figure 4, the oscillator passes through an opening start position just before reaching the position without opening latch. When the oscillator reaches the opening start position, the surface 154 of the cam plate 146 of the oscillator engages the fin plate 196, and flips it in the right-to-left direction about the axis 200. A projection onto the plate 196 the finger 176 engages the opening trap, thereby forcing the opening trap in a right-to-left direction against the pressure of the spring 182. The tip of the trap roller 174 is lifted out of the slot 140 in the bell crank 134b. It should be appreciated that the surface of the trap 154 does not engage the fin plate, and the fin plate does not engage the finger 176 until the cam 146 is almost at the end of its rotary movement from right to left. The complete action of lifting the roller tip 174 out of the slot 140 occurs on a very short rotational movement of the oscillator 146, between the opening start position and the position without opening latch.

When the roller tip 174 clears the slot 140, the opening spring 156 urges the bell handle 134 in rotation in a right-to-left closing direction as seen in FIGS. 3 and 4 until the crank elements of the bell reach the position illustrated in Figure 5. The components are dimensioned so that the opening spring remains under tension through the opening movement of the bell handle. Therefore, the backward or opening movement pulls the clamping bolt of the opening side 153 on the oscillator, from the fully closed position of Figure 3 to the fully open position of Figure 5, is greater than the backward movement. or the opening stroke of the clamping bolt of the opening side 135 on the bell crank. Conversely, the forward movement of the locking side bolt 154 of the oscillator is greater than the forward movement of the corresponding bolt 137 of the bell crank. Therefore, the closing side spring is brought to a loosened condition and remains loose when the bell handle reaches the open position illustrated in Figure 5. Any excess movement of the bolt 154 beyond that required to carry the spring on the side closing to a completely loosened condition is taken by the movement of the bolt within the end circuit of the spring; the spring on the closing side is not placed in compression. The continued presence of the tension in the spring of the opening side through the opening movement helps to ensure that the mechanism does not stop something from the intermediate position during the opening stroke. In effect, the end circuits and the bolts serve as a lost motion joint connected in series with the opening side spring 156 between the clamping points on the opening side of the bell crank and the oscillator and a motion joint additional loss connected in series with the spring of the closing side 158 between the clamping points of the closing side of the bell crank and the oscillator.

The bolts 171 on the bell crank pull the drive links 166 with these and thus move the movable member 124 of the drive mechanism in the opening direction (to be on the left as seen in the drawings). Therefore, the movable element pulls the actuating element 108, the yoke 102 (FIG. 1), the bolt 106, the link 98 and the operating element 72 in the opening direction. Therefore the movable contact 70 moves to its open position. This movement occurs suddenly, thus minimizing any possibility of arcing between the contacts. When moving the bell crank elements the open position of figure 5, the tip 190 of the closing trap 186 engages in the slot 140 of the bell handle 134a under the influence of the spring 196. This closes the mechanism in the open position illustrated in FIG. 5. The closing operation operates in a similar way but with a reverse rotation. Therefore, the operator operates the handle so as to flip the operating shaft and oscillator 146 in a closing direction or from left to right allowing the opening spring 156 to relax and stretch the closing spring 158, as the pin moves backwardly. side closure 154 of the oscillator. On approaching the mechanism to the position without closing latch of figure 6, it passes through a closing start position in which the trap surface 152 on the cam engages the fin plate 196, so that a projection 198a of the plate engages the finger 194 of the closure trap, thereby lifting the roller tip 190 out of contact with the slot 140 in the bell handle 134a. When the oscillator reaches the position without closing latch and the tip 190 clears the slot, the closing spring 158 pulls the clamping bolt on the closing side 137 of the bell crank rearwardly and thereby urges the bell crank 134a into rotation in a closing direction from left to right as seen in the drawings, until the bell handle reaches the closed position illustrated in figure 3. By turning the bell handle to the closed position, this forces the pin 171 and by both to the drive link 166 and to the movable member 124 in the closing direction, thereby forcing all other elements of the switch and the final movable contact 70 in the closing direction, to the closed position shown in FIG. 1. Spring on the closing side remains under tension through the closing cycle, and remains under tension when the bell handle reaches the closed position. To provide such tension, the backward movement or pull of the clamping point of the closing side 154 on the oscillator is greater than the backward or sharp movement of the closing side point 137 on the oscillator. The closing rotation of the cam plate 40 is stopped by the stops 202 and the fin plate 196. The closing movement of the bell cranks (from the position of figure 6 to the position of figure 3) carries the bolts 171 in alignment with bolts 138 and 168. As the bolts 171 approach this position, the articulation provides a circumstantial mechanical advantage, so that the movable member 124 is driven in the closing direction with substantial force. The connection between the movable member 124 and actuator element 108 is adjusted so that the movable contact 70 engages the fixed contact 68 slightly before it completes the closing movement of the drive mechanism. The final movement of the drive mechanism after the contact is accommodated by the sliding movement of the yoke 102 (FIG. 1) in relation to the link 98, against the pressure of the spring 104. This movement minimizes the mechanical shock load applied to the arms. contacts The loads which are applied to the contact assembly during the closing movement are transmitted through the fixed contact 68, the end cover 64 and the fixed end reinforcement 82 to the reinforcing element 36 through the threaded connection 40. Essentially none of these charges are applied to the bottle 62. The loads applied to the reinforcing element 36 tend to move it in the closing direction (to the right in Figure 1) in relation to the driving frame. However, the outer reinforcing element 42 is fixed by the driving frame by the ring 128. The outer reinforcing element restricts the box 10, which in turn restricts the reinforcing element. The inner and outer reinforcing elements 36 and 42 are telescoped together, and the box 10 is hooked onto the large surface boxes with only a thin annular part of the case elastomer interposed therebetween. This forms a gasket resistant to liquid tension to which it firmly supports the reinforcing element 36 against movement. The actuator or drive discussed above provides significant advantages. This moves the contact quickly between the open and closed positions to minimize arcing. The drive mechanism is extremely compact. The complete mechanism is accommodated in a tubular box of essentially the same diameter as the external reinforcing element of the commutator. A 0-ring or other conventional seals (not shown) can be provided between the tubular driver casing 131, the rings 128 and 129 and as to provide a weatherproof seal protector protecting the elements of the drive mechanism. The driving box 131 is also provided with a hole (not shown) for the passage of the handle 145. This hole can be provided with appropriate seals.

Even when the actuator can be made in essentially any size, to fit in any high-voltage switch, a useful actuator has the opening and closing spring with the spring constants of about 16 pounds / inch or 175.2N / m and has a Bell crank with a moment of inertia about the bell crank axis of about .0009 kg-m2 in each main spring is stretched by about 0.97 inches or 25 mm. during movement of the oscillator to the position without closing latch or without opening latch. The distance between the bell crank axis and the oscillator axis is around 51 mm. , while the radial distance from the oscillating shaft 142 to each of the fastening bolts of the closing side and of the opening side 153 and 154 is about 35 mm. The radial distance from the bell crank shaft 138 to each of the opening side and the closing side fastening bolts 135 and 137 is 40 mm.

As will be appreciated, numerous variations and combinations of the features discussed above may be used without departing from the present invention, as defined by the clauses. For example, other switches than those described in the application may be used.

Luzzy in conjunction with the actuator. Also, oscillator 146 of the actuator may be driven in a pivoting motion by an automatic device rather than by a manual operation. The arrangement of the lost motion using the spring-end circuits can be replaced by other forms of lost motion joints. Therefore, the above description of the preferred embodiments should be taken by way of limitation of the invention.

Claims (18)

1. An actuator for a high voltage switch comprising: (a) an impeller frame defining a bell crank pivot axis and an oscillator pivot shaft parallel to the bell crank pivot axis, but spaced in a rearward direction therefrom; (b) a bell crank mounted on the frame for a pivot movement about the bell crank pivot axis, the bell crank element has an opening side fitting and a closing side fitting, the crank bell being pivotable between an open position and a closed position; (c) an oscillator mounted to the frame for a pivot movement about said oscillator pivot axis, the oscillator has a point of attachment of the opening side, the oscillator being pivotable between a fully closed position and a fully open position. (d) a spring on the opening side connected between the clamping points on the opening side of said oscillator and said bell crank and a spring on the closing side connected between the clamping points on the closing side of said oscillator and said bell crank so that the spring on the opening side will deform and the energy will be stored there with the movement of the oscillator from its fully closed position to its fully open position, while the bell crank remains in its closed position and so that the spring on the opening side will deform and the energy will be stored there with the movement of the oscillator from its fully open position to its fully closed position, while the bell crank remains in its open position; (e) a trap on the opening side for restricting said bell crank against the opening pivot movement when said bell crank is in a closed position thereof and a closing side trap for restricting said bell crank on against the closing pivot movement when said bell handle is in said open position thereof; (f) the trap release means for disengaging said trap from the opening side when said oscillator reaches a position without opening latch near the fully open position during the opening movement thereof and disengaging said trap from the opening side when said oscillator reaches a position without closing latch near the fully closed position during the closing movement thereof; (g) mounting means for connecting said frame of a body of a high voltage switch and connecting said bell handle to an actuating element of the switch, whereby when the oscillator pivots in closing movement, said spring of the closing side it will deform until the oscillator reaches the position without closing latch, whereby the spring on the closing side will urge the bell crank in a pivoting movement towards its closed position and will urge the actuating element of the switch rapidly towards a closed position of the latch. same and when the oscillator pivots in an opening movement said spring on the opening side will deform until the oscillator reaches the position without opening latch, whereby the spring on the opening side will urge the bell crank in the pivoting movement to its open position and will drive the actuating movement of the switch rapidly towards a closed position thereof.

2. An actuator as claimed in clause 1 characterized in that the pivot axis defines a common plane, said accessories on the opening side of said oscillator and said bell crank being positioned on an opening side of the common plane, said accessories on the closing side of said oscillator and said bell crank are placed on an opposite closing side of said opening side, the fixture on the opening side of the bell crank moves backwards during the pivoting movement of the bell crank from the open position and said fixture on the closing side of the bell crank moves back during the movement of the bell crank. In the case of a bell towards said closing, the attachment of the closing side of the oscillator moves backwards during the pivoting movement of the oscillator to its fully closed position, the accessory of the opening side of the oscillator moves backwards during the pivoting movement of the oscillator. oscillator to its fully open position.

3. An actuator as claimed in clause 2 characterized in that said bell crank includes a pair of elements spaced apart from one another and said oscillator includes a pair of elements spaced apart from one another, said plates of said bell crank and said plates of said oscillator element cooperatively define a channel of the closing side on said closing side of said plane and a channel of the opening side on said opening side of said plane, said springs being received in said channels.

4. An actuator as claimed in clause 3, characterized in that each spring is a spiral tension spring.

5. An actuator as claimed in clause 4 characterized in that said elements of said bell crank and said oscillator interengage with one another so as to form virtually continuous walls on the opposite sides of said channel of the opening side when said oscillator is in the position without closing latch, and as to form virtually continuous walls on the opposite sides of the closing side channel when said oscillator is in the position without opening latch, whereby the continuous walls will restrict said opening spring during movement of closing said bell crank and restraining said closing spring during the opening movement of said bell crank.

6. An actuator as claimed in clause 1 characterized in that said trap release means are arranged to leave the opening trap engaged during the opening movement of said oscillator from said fully closed position to an opening start position close to the position without opening latch, and for leaving the closing trap engaged during the closing movement of said oscillator from the fully open position to a closing start position near the position without opening latch.

7. An actuator as claimed in clause 6 characterized in that said trap release means includes a flap movably mounted to said frame, so that the flap will move the aperture trap with movement relative to the frame in a first direction and will move the closing trap with a movement in a second direction, said oscillator includes an aperture projection adapted to engage the fin and move the fin in said first direction, when the oscillator reaches the opening start position in the. opening movement and a closing projection spaced apart from the opening projection, the closing projection engages the flap when the oscillator reaches the closing start position in the closing movement position.

8. An actuator as claimed in clause 7, characterized in that said traps are mounted in pivoting form in said frame for movement about the oscillating axis, and wherein said oscillator is pivotally mounted to the frame on a fin axis. parallel to said oscillator axis.

9. An actuator as claimed in clause 8 characterized in that said bell crank defines at least one generally arcuate surface having a notch therein and each of said traps includes a catch-able tip with a notch.

10. An actuator as claimed in clause 1 characterized in that said mounting means include means of non-uniform articulation to articulate the bell crank to the actuating element of the switch, to provide a non-uniform cup between the movement of the actuating element and the movement of the bell crank, so that each increase in the bell crank movement produces a relatively small movement of the actuator element when the bell crank is adjacent to its closed position and produces a relatively large movement of the actuating element when the bell crank it is next to its open position.

11. An actuator as claimed in clause 10 characterized in that said non-uniform articulation includes a plurality of links connected to each other, to the bell crank and said frame so that the bell crank, the frame and the links cooperatively they constitute a four-bar joint.

12. An actuator as claimed in clause 1 characterized in that said oscillator, said bell crank and said spring are constructed and arranged so that the spring of the opening side continues to press said bell crank towards the open position during the movement of full opening thereof so that said closing-side spring continues to press the bell crank towards the closed position during the full closing movement thereof.

13. An actuator as claimed in clause 12 characterized in that said springs are tension springs, said clamping of the opening side of the oscillator moves throan aperture throw distance during movement of the oscillator from its fully closed position to its fully open position and said opening side fitting of said bell crank moves throan aperture blow distance, said aperture throw distance being greater than the aperture stroke distance and wherein said aperture distance The closing side of said oscillator moves throa closing draft distance during movement of the oscillator from its fully closed position to its fully open position and said accessory of the closing side of said bell handle moves throa closing hit distance, said closing throw distance being greater than the closing hit distance.

14. An actuator as claimed in clause 13 characterized in that it comprises a mechanism of motion lost from the opening side connected in series with said opening-side spring between said accessories of the opening side and the movement mechanism lost from the closing side connected in series with said closing side spring between said closing side fittings.

15. An actuator as claimed in clause 14 characterized in that said spring includes at least one end circuit having an inner diameter, at least one of the accessories of the opening side includes a pin received in said end circuit of the opening side spring and having an outside diameter smaller than the inside diameter of such end circuit, at least one of said end side fittings includes a bolt received in one of said end circuits of the spring side of the closing side and having an outer diameter smaller than the inner diameter of such end circuit, said lost motion mechanism, includes said end circuits and bolts.

16. An actuator as claimed in clause 1 characterized in that it also comprises a generally tubular box surrounding and enclosing the aforementioned components of the actuator.

17. An actuator as claimed in clause 16 characterized in that said frame includes a pair of plates that extend back and forth within said box, said plates being transverse to said axes and spaced apart from each other, said bell crank and said oscillator being placed between said plates.

18. An actuator as claimed in clause 17 characterized in that said frame further includes a pair of rings at the front and rear ends of said plates, said tubular box being supported on said rings.