Claims:1. An electrically operated control mechanism (1) for an electrical cut-off device (2), the control mechanism (1) comprising
housing means comprising a bottom housing (3) and a top housing (7) so as to enclose a bridge assembly (4) having a rack type gear (12); a coil assembly having a first coil (6) and a second coil (11); a control circuit assembly (10); a plunger (5) operably placed within the coil assembly (6, 11) and operably coupled to engage the bridge assembly (4); and
gear means (13, 14, 15) mechanically coupled to the bridge assembly (4) so as to convert the linear output of the plunger (5) into a rotatory motion to control the cut-off device.

2. The control mechanism as claimed in claim 1, wherein the coil assembly (6, 11) consists of a U shaped core (6a, 11a) and a closing core (6c, 11c) which forms the magnetic path along with a bobbin in which the coil is wound (6b, 11b) that generates the magnetic energy once energized.

3. The control mechanism as claimed in claim 1, wherein the bridge assembly (4) comprises a bridge housing (16), stopping means (17, 21) operably coupled to latching means (20, 24), said stopping means comprises a first stopper (17) coupled to two compression springs (18), a second stopper coupled to two compression springs (22), said latching means comprises a first latch (20) operably coupled to engage the first stopper (17) and held together by a first pin (19), a second latch (24) operably coupled to engage the second stopper (21) and held together by a second pin (23).

4. The control mechanism as claimed in claim 1, wherein the plunger (5) houses at least two compression springs (28, 29) on either side, inside the coil assembly (6, 11), operably placed between the U shaped cores (6a, 11a) of coil and the plunger (5), so as to maintain the plunger midway between the coils after any operation.

5. The control mechanism as claimed in claim 1, wherein the gear means comprises a first spur gear (13), rotatably coupled to a second spur gear (14) and a third spur gear (15) to an output shaft (25) connected to the third spur gear (15), so as to transfer the power output of coil assembly available at the plunger (5) to the cut-off device (2).

6. The control mechanism as claimed in claim 5, wherein the gear means can be made to increase/decrease the torque generated at the output shaft (25) with corresponding decrease/increase in the angle of rotation of output shaft (25).
, Description:FIELD OF INVENTION
The present invention relates to solenoid based double stroke mechanism in general, more particularly to an Electrically Operating mechanism (EOM) for Changeover Switch.

BACKGROUND

Changeover switch-disconnectors (CO-SD) are widely used to switch between primary and backup power source. These Switches comprise of 2 Switch-Disconnectors (SD) connected back-to-back. Changeover switch-disconnectors have three stable positions-ON1, OFF, ON2 (based on the power source). Certain torque is required to drive the switch to these positions. The Torque required to switch ON or OFF a Changeover Switch-disconnector varies depending upon the constructional requirement of the mechanism inside it. The Torque requirement generally increases as the rating (in terms of Ampere) of the CO-SD increases. Electrically operating mechanism (EOM) is used to ease the operation by giving the required torque without manual effort. As it is called, it works on electrical power. Electrically Operating Mechanism (EOM) is generally driven by a motor or solenoid which acts as the prime mover.
In solenoid based mechanism, the shaft of the CO-SD is operated through the force and stroke generated by the solenoid coil. The same is transmitted vide a gear arrangement to convert it to the required angle of rotation and torque. Electrical supply to EOM is controlled through a control circuit which logically determines the command based on the current position of CO-SD. The gear arrangement is such that the power from the solenoid coil is effectively converted and transmitted to the driving shaft which operates the CO-SD. The Driving shaft is the connecting member between EOM and CO-SD, which transmits the torque generated by the EOM to the CO-SD. In the event of loss of control supply to operate the EOM, provision to operate the CO-SD manually by the operator is required. Such a provision should be made so that the operator’s efforts are minimal.
Reference has been made to US20090032379A1, an automated control module for an electrical cut-off apparatus including an automated actuation mechanism (30) having two electromagnets (31) aligned in opposition on a slide (34) bearing a rack (35) which meshes with a driving pinion (40). The driving pinion (40) can rotate about a drive spindle (50) which is intended to be rotationally coupled to the drive shaft of the cut-off apparatus (1). The drive spindle (50) includes a ratchet wheel (51) driven in one direction or another by pawls (43) fastened to the driving pinion (40) so as to switch the cut-off apparatus (1) according to the controlled electromagnet. This control module (10) also includes a manual actuation mechanism (60) and automatic clutch mechanism for disengaging one of the mechanisms (30 or 60) when the other mechanism is in operation disclosing. The mechanism employs ratchet type arrangement to achieve the independency of the driving member while the plunger returns back to its initial position. The mechanism also has inbuilt provision to operate the switch manually through an external handle. This system is not meant to drive an external mechanism but rather has the entire switching mechanism inbuilt.
Reference has been made to US3070730, which teaches a three position solenoid controlled actuating device has a number of possible applications. This invention relates to solenoid actuators and more particularly to an actuator capable of providing three possible axial positions on an output shaft. It employs a permanent magnet to hold the plunger in between the 2 coils and there is provision to achieve 3 distinct output positions by energizing each coil and de-energizing both coils.
Reference has been further made to US3221191, teaching an angular rotary-type solenoid which, with minor adjustments, may be given torque-angle characteristics over a wide angular turning range. Rotary output is achieved using an armature rotor and stator construction in which the rotor is mounted on the central portion of an E-shaped stator.
Yet another reference has been made to US4236130 disclosing solenoid comprises an electric coil having an opening through it and an armature of permeable material having in fixed relative relationship a core passing through the opening of the coil and a sleeve surrounding the coil. The armature is unmagnetized except for magnetization induced by current flow through the coil. The coil and the armature are relatively movable in an axial direction to vary the extent of overlap there between. A pole piece of permeable material connects the sleeve to the core at one end. A pole piece of permeable material is fastened to the end of the coil opposite to the first named pole piece. In one embodiment the core is movable relative to the sheath prior to energization of the coil, to permit the coil to be preset to one of two positions in gapless relationship with the sheath.
Reference has been made to US4999598 disclosing three-position actuating mechanism (10) for a transfer switch (11) is disclosed. The transfer switch is movable by the actuator (10) between a contact block (13) corresponding to a normal power source, and a contact block (14) interconnected to a standby or emergency power source. The actuator (10) has a pair of disk drives (22, 23) interconnected to solenoids (20, 21) by means of linkages (33, 34). The disk drives (22, 23) are interconnected to each other and to a driven disk (26) by means of a pin (30). Energization of the solenoids (20, 21) causes movement of the corresponding solenoid plunger (31, 32) and rotation of the disk drives (22, 23), so as to cause rotation of the contact crossbar (16) and transfer of the contacts (15, 18) between the two power sources. This system is also not meant to drive an external mechanism.
In the prior art, some of the technical problems faced are that the stroke length of the coil is limited to the length of the coil, solenoid coils are not meant to drive an external rotary mechanism, inertial energy during high speed operation may induce over travel in intermediate position and there are no provisions for increasing the output displacement or force/torque. Solenoid based mechanisms often have limitations on the length of the stroke as it tends to make the coils bulkier.
As a basic characteristic of solenoids, the force generated tends to increase linearly till saturation as the plunger enters the coil. This implies that higher force cannot be initiated at the start point. In case, higher force is generated at / near to start point of coil, the force further increases as it progresses. This additional force is not utilized in such cases and hence is a loss of energy.
To overcome aforementioned problems, thus there is a need for a double stroke mechanism in EOM that doubles the stroke length to provide higher rotation angle or increased torque and also provides two independent operations along same direction of operation.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
An object of the present invention is to provide a solenoid based double stroke mechanism in Electrically Operating mechanism (EOM) for Changeover Switch-disconnector.
An object of the present invention is to provide a solenoid based mechanism to perform two strokes of coil thereby attaining double the stroke length as compared to conventional solenoid coils.
An object of the present invention is to provide a solenoid based double stroke mechanism, where the length of solenoid comes down to half of required stroke length wherein very high force / stable force is required over the entire stroke.
Yet another object of the present invention is to provide a solenoid based double stroke mechanism having increased force/stroke output for a smaller coil length, reduced power input and solenoid size compared to single longer stroke mechanism.
Yet another object of the present invention is to provide a solenoid based double stroke mechanism where the solenoid coil output is linear which can be converted to rotary torque with required multiplication factor for increasing torque or angular displacement as per the demand of the load/mechanism to be driven.
In accordance with an aspect of the present disclosure, is to provide an electrically operated control mechanism for an electrical cut-off device, the control mechanism comprising housing means comprising a bottom housing and a top housing so as to enclose a bridge assembly having a rack type gear, a coil assembly having a first coil and a second coil, a control circuit assembly, a plunger operably placed within the coil assembly and operably coupled to engage the bridge assembly and gear means mechanically coupled to the bridge assembly so as to convert the linear output of the plunger into a rotatory motion to control the cut-off device.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:
Figure 1 illustrates an isometric view of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 2 illustrates an exploded view of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 3 illustrates the working components of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 4 illustrates the exploded view of a coil assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 5 illustrates the exploded view of a bridge assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figures 6-7 illustrate the isometric, top, bottom, left and right view of a bridge assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 8 illustrates an exploded view of a stopper and a latch lateral of a bridge assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 9 illustrates 3 distinct positions which the stopper-right and latch-right of a bridge assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device can take in accordance to the invention.
Figures 10-11 illustrate a cross-section view of the solenoid based electrically operating mechanism corresponding to OFF position of the electrical cut-off device in accordance to the invention.
Figures 12-18 illustrate the movement of a bridge assembly and operation of a stopper-right and a latch-right towards the left side of the bridge assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Figure 19 illustrates an isometric view of the complete sequence of operation from OFF - Position I – OFF - Position II – OFF with the intermediate positions of engagement and disengagement of stopper-left and stopper-right of the bridge assembly of the solenoid based electrically operating mechanism connected to an electrical cut-off device in accordance to the invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.
It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.
All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments belong. Further, the meaning of terms or words used in the specification and the claims should not be limited to the literal or commonly employed sense, but should be construed in accordance with the spirit of the disclosure to most properly describe the present disclosure.
The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. Also, Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
The present disclosure will now be described more fully with reference to the accompanying drawings, in which various embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the various embodiments set forth herein, rather, these various embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the present disclosure. Furthermore, a detailed description of other parts will not be provided not to make the present disclosure unclear. Like reference numerals in the drawings refer to like elements throughout.
The subject invention lies in providing a solenoid based double stroke mechanism which is achieved by the bridge assembly that allows the plunger of a solenoid coil to return to its initial position after each operation i.e. stroke. The bridge assembly connected to the output remains standstill while only the plunger returns back to its initial position post the intended operation. This mechanism enables the solenoid coil to get energized twice in the same direction. This doubles the overall output in terms of linear movement which can either be used for increasing the rotation angle at output or increase the torque output, based on the gear conversion.
An embodiment of the present invention as shown is for an electrically operating mechanism for changeover switch-disconnector which has an OFF position at the center and ON1, ON2 positions at 50° in clockwise, anticlockwise directions respectively. In electrical/power operation, the gear train is driven by a prime mover (i.e. solenoid) which in turn drives the output shaft. In case of non-availability or failure of power, manual operation is used in which the shaft is driven through a handle manually by the user.
The construction described herein can be modified accordingly to suit a variety of applications and the construction shown below does not limit its application to the above system alone.
According to an exemplary embodiment of the present invention, an electrically operated control mechanism (1) for an electrical cut-off device (2) has been disclosed. The control mechanism (1) comprises a bottom housing (3) and a top housing (7) so as to enclose a bridge assembly (4) having a rack type gear (12), a coil assembly having a first coil (6) and a second coil (11), a control circuit assembly (10), a plunger (5) operably placed within the coil assembly (6, 11) and operably coupled to engage the bridge assembly (4). The control mechanism further comprises gear means comprising a plurality of gears (13, 14, 15) mechanically coupled to the bridge assembly (4) so as to convert the linear output of the plunger (5) into a rotatory motion to control the cut-off device. According to an embodiment the electrical cut-off device is a Changeover switch-disconnector, CO-SD.
Referring to figure 1, illustrating an isometric view of the entire system i.e. solenoid based electrically operating mechanism, EOM (1) is connected to an electrical cut-off device which is a Changeover switch-disconnector, CO-SD (2). The Output of EOM (1) is transferred to CO-SD to complete its operation i.e. switching ON-OFF power sources to the load.
Referring to figure 2, the EOM module comprises of a base housing (3) which provides the position reference for the components like bridge assembly (4), coil assembly (6, 11) and control circuit assembly (10). The plunger (5) gets its axial movement reference from the coil assembly. Top housing (7) provides a closed compartment structure to the coil and bridge assembly housed in the base housing. Gear housing (8, 9) provides the axial reference for gears and connects with the CO-SD.
Referring to figure 3, shows the working components that generate and transmit power in particular the connection established between the solenoid coil and gears till the output shaft (25). The plunger (5) is assembled inside the coil assemblies (6, 11) with its extended member (5a) connected with the bridge assembly (4). Bridge assembly has a rack type gear (12) on the lateral side which is used to convert the linear output of the plunger into a rotatory motion through the first stage spur gear (13). The rotary motion in first stage of spur gear (13) is further connected through the second and third stage spur gear (14, 15) to the output shaft (25) connected to the third stage spur gear (15). These gear stages are used to transfer the power output of solenoid coils available at the plunger to the CO-SD. The gear stages can be made to increase/decrease the torque generated at the output shaft with corresponding decrease/increase in the angle of rotation of output shaft. For illustration idle gear stage are used and hence torque delivery remains same at all 3 spur gear stages but the same can be modified to suit the needs of the system in which it is being used.

Referring to figure 4, each coil assembly (6, 11) consists of a U shaped core (6a) and closing core (6c) which forms the magnetic path along with the bobbin in which the coil is wound (6b) that generates the magnetic energy once energized. The U-type core with closing core is for illustration purpose and the same can be modified based on need. The construction of coil assembly 2 (11) would be of similar nature.
Referring to figure 5 the bridge assembly (4) comprises of a bridge (16) which houses a stopper-left (17) which is pushed upward by two compression springs (18) and a latch-left (20) pushed downwards by another compression spring (similar to 26 in figure 8). Similarly, a stopper-right (21) with its springs (22) and a latch-right (24) is housed on the other side of the bridge. The stopper and latch are held together by their respective pins (19, 23) post assembly into the bridge.
Referring to figure 6, the bridge (16) has slots for movement of stopper-left and stopper-right (16a, 16b) and the openings for guiding latch-left and latch-right (16c, 16d). Referring to figure 8, the stopper-right (21) is operably coupled to the latch-right (24) and pin (23) along with the respective compression springs (22, 26).
Referring to figure 9, giving an illustration of three distinct positions which the stopper-right (21) and latch-right (24) can take. In the first position, latch-right (24) is pushed down into the slot (31) by its spring (26). This action forces the stopper-right (21) to be pulled down because of the connection through pin (23) thereby compressing its springs (22). In the second position, the bridge assembly is away from the slot (31) and latch-right (24) is pushed upward compressing its spring (26). This allows the stopper-right (21) to move upward as the pin (23) is free to move in the slot of stopper-right (21). The compression springs (22) push the stopper-right (21) upward till the pin is at the end of its slot. In the last position, the stopper-right (21) is pushed downward compressing its springs (22). Since the pin is free to move over the slot in the stopper-right, this action is possible. The first two positions are based on the position of the bridge assembly (4) in the base housing (3) while the last position is achieved through an external push force on stopper-right (21). All the three positions come into effect during the operation of the mechanism. Similar positions exist for the other set i.e. stopper-left (17), latch-left (20) through their respective springs (18, 27) and slot (30) in base housing. The compression springs are designed such that the spring is latch is able to compress the springs in stopper and pull it downward. The springs in stopper are kept low on force sufficient to lift up the stopper when it is allowed by the latch.
Figure 10 illustrates the cross-section view of EOM corresponding to OFF position of CO-SD. Section is shown such that the Stopper-left (17) is visible with latch-left (20) and its corresponding slot (30) in base housing (3). The extended actuator of plunger (5a) is ready to engage with the stopper (17) and move the complete bridge assembly (4) when the plunger (5) is pulled by coil assembly 1 (6). Also, the latch will not pull down the stopper during the movement of bridge assembly (4) towards coil assembly 1 (6) as its slot (30) in base housing is on the other side i.e. towards coil assembly 2 (11). The plunger also houses 2 compression springs (28, 29) on either side inside the coil assembly. These springs are placed between the U-core of coil and plunger so that they tend to maintain the plunger in the initial position (midway between the coils) after any operation.
Figure 11 illustrates the cross-section view of EOM corresponding to OFF position of CO-SD. This section is shown such that the Stopper-right (21) is visible with latch-right (24) and its corresponding slot (31) in base housing (3). The extended actuator of plunger (5a) is ready to engage with the stopper (21) and move the complete bridge assembly (4) when the plunger (5) is pulled by coil assembly 2 (11). Similar to previous case, here the latch will not pull down the stopper during the movement of bridge assembly (4) towards coil assembly 2 (11) as its slot (31) in base housing is on the other side i.e. towards coil assembly 1 (6).
Figures 12-18 illustrate the movement of bridge assembly and the operation of stopper-right (21), latch-right (24) towards the left side of the assembly. The operation of stopper-left and latch-left is similar on the other side of the assembly while the bridge assembly moves towards the right side of the assembly. The gear train rotates corresponding to the movement of the bridge assembly (4) through the connection of rack gear (12) thereby transferring the required torque to operate the CO-SD through the shaft.
Figure 12 illustrates the cross-section of assembly wherein the actuator of plunger (5a) has engaged with stopper-left (17). The pulling force generated on the plunger (5) by energizing coil assembly 1 (6) (by applying electrical supply to coil (6b)) has moved the plunger and its actuator towards coil assembly 1 (6). During this action, the actuator pushes the stopper-left (17) which in turn moves the entire bridge assembly (4) with it as it is engaged with the bridge (16). While the plunger is half the way, the latch-right (24) tends to get into its slot (31) in the base housing (3) because of the force delivered by its spring (26). This pulls down the stopper-right (21) along with it through the pin (23) compressing the springs (22). The Plunger also compresses the spring (28) in coil assembly 1 (6) against the U-core (6a) during this movement while the spring (29) gets de-energized in coil assembly 2 (11).
Figure 13 illustrates the position in which the operation is complete and the CO-SD has reached Position-I. The plunger (5) has hit the end of the coil i.e. the U-core (6a). At this point, the stopper-right (21) is completely flushed inside bridge (16) because of the pull-down by latch-right (24). The spring (28) in coil assembly 1 (6) is completely energized while the plunger (5) is still inside the Closing-core (11c) of coil assembly 2 (11) to maintain axial reference during return movement. Once this position is reached, the control circuit is set such that the supply to the coil assembly 1 (6) is cut off. Once the supply is cut off, the coil (6b) gets de-energized and there will be no pulling force on the plunger (5). The energy stored in compression spring (28) now tends to push the plunger (5) away from the coil assembly (6). The actuator of plunger (5a) is also free to move towards coil assembly 2 (11) without moving the bridge assembly (4) as the stopper-right (21) is flushed.
Figure 14 illustrates the position in which the plunger (5) has returned to its initial position. The actuator (5a) is ready for engagement with the bridge (16). At this point, both the springs (28, 29) inside the coil assembly exert equally opposite force thus maintaining equilibrium. The entire bridge assembly (4) with stopper and latch remain in the previous position i.e. as in Image 13. From this position, even if coil assembly 1 (6) is energized, the plunger (5) would move towards the coil (6) but the bridge (will remain at the same position and hence, no output is delivered to CO-SD through the gear train. This avoids malfunctions in case of any failure in control circuit or abuse by the user.
Referring to figure 15, the position in which the coil assembly 2 (11) has been energized and the plunger (5) is pulled toward it has been shown. The actuator of plunger (5a) is engaged with the bridge (16) pushing the entire bridge assembly (4) towards coil assembly 2 (11). As the bridge moves, the latch-right (24) moves upward due to the interaction of its slanting surface with the slot (31) in base housing. The spring (26) is compressed and the stopper-right (21) also moves upwards due to its springs (22). The pin (23) controls its movement upwards. While the spring (29) in coil assembly 2 (11) gets compressed & energized during this action, the other spring (28) in coil assembly 1 (6) gets de-energized. Though the bridge (16) position is same as in Image 12, it can be noted that the plunger (5) position is different.
Figure 16 illustrates the condition wherein the plunger (5) movement is complete and has hit the U-core (11a) of coil assembly 2 (11). The bridge (16) has come back to its initial position i.e. OFF position of CO-SD as in Image 10. The Plunger (5) is still inside closing core (6c) of coil assembly 1 (6) to retain the reference for axial return movement. Latch-right (24) has completely come outside of its slot (31) and the stopper-right (21) has also moved upwards to be ready to engage with the actuator (5a) of plunger. The spring in coil assembly 2 (11) is completely compressed and ready to de-energize while the other spring in coil assembly 1 (6) is in de-energized condition. Once this position is reached, the supply to coil (11b) is cut-off similar to the condition in Image 13. Once the coil gets de-energized, the energy in spring (29) pushes the plunger (5) towards coil assembly 1 (6). The actuator (5a) during the return movement pushes down stopper-right (21) and reaches its initial position which is explained in further images.
Figure 17 shows the condition in which the plunger (5) is pushed towards coil assembly 1 (6). The actuator (5a) of plunger (5) is pushing the stopper-right (21) downward overcoming the force of its springs (22). The spring (29) is set to exert a force high enough to overcome spring (22) in stopper-right (21).
As shown in figure 18, the plunger (5) has returned back to its initial position. The force exerted by springs (28, 29) in the first coil assembly (6) and the second coil assembly (11) have become equal and opposite thereby maintaining the position of plunger in the said location. Stopper-right (21) moves upward to its initial position once the actuator (5a) of plunger (5) crosses the same. This position is same as that of figure 11 which is the start point of the operating cycle.
Similarly, the operation occurs with other set i.e. the stopper-left (17) and the latch-left (20) with their respective springs (18, 27) for operating the CO-SD to Position-II and back to OFF position.
Figure 19 shows the complete sequence of operation from OFF - Position I - OFF - Position II - OFF with the intermediate positions of engagement and disengagement of stopper-left and right in isometric view.
Some of the non-limiting advantages of the present invention are:
a) Stable OFF operation is achieved though it is an intermediate position for the Changeover Switch-Disconnector.
b) Higher linear movement and corresponding rotary motion is achieved with half of the coil length.
c) Size, cost and energy savings achieved by controlling the higher force at the end of coil stroke.
d) Reduced wastage of power output by limiting the power output at the end.
e) Three distinct positions are achieved with the mechanism and it can be extended further with suitable modifications.
f) Reliable intermediate position is achieved as the plunger movement is restricted by the core of the coil. The bridge movement is restricted by the actuator of plunger thereby eliminating the unintended effects of inertia during operation of coil.

Although an electrically operated control mechanism for an electrical cut-off device thereof has been described in language specific to structural features, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific methods or devices described herein. Rather, the specific features are disclosed as examples of implementations of an electrically operated control mechanism for an electrical cut-off device.

List of parts/components:

1. Solenoid based mechanism for electrically operating Changeover switch-disconnector
2. Changeover switch-disconnector
3. Base housing
4. Bridge assembly
5. Plunger with an extended actuator (5a)
6. Coil assembly 1 with U-core (6a), Bobbin with coil wound (6b) and Closing core (6c)
7. Top housing
8. Gear housing 1
9. Gear housing 2
10. Control circuit assembly (indicative)
11. Coil assembly 2 (similar to coil assembly 1)
12. Rack gear fixed to bridge assembly
13. First stage of spur gear
14. Second stage of spur gear
15. Final stage of spur gear
16. Bridge with guiding slots for stopper (16a, 16b) and Latch (16c, 16d)
17. Stopper-left
18. Compression springs for stopper-left
19. Pin for Stopper-left
20. Latch-left
21. Stopper-right
22. Compression springs for stopper-right
23. Pin for Stopper-right
24. Latch-right
25. Operating shaft connecting Solenoid mechanism and Changeover switch-disconnector
26. Compression spring for latch-right
27. Compression spring for latch-left
28. Compression spring for coil assembly 1
29. Compression spring for coil assembly 2