Claims:1. An interlocking mechanism in motor operators for molded case circuit breakers (MCCB), wherein said mechanism comprising:
a mode selector assembly having a base and a slider switch means adapted to actuate or de-actuate one or more micro switches to make electrical connectivity or cut-off;
a padlock-latch assembly interacting with said mode selector assembly and being compacted in a housing with a housing cover, wherein said padlock-latch assembly comprises one or more padlock hasp means having a cam profiled protrusion, and at least one hasp latch means;
wherein during a LOCK mode operation enabled by said mode selector assembly, said padlock hasp means when enabled by said hasp latch means, pop-up due to spring action of at least one padlock hasp retention spring means, and allow a user to apply one or more locking means.
2. The interlock mechanism as claimed in claim 1, wherein said padlock hasp means blocked in AUTO and MANUAL mode enabled by said mode selector assembly.
3. The interlock mechanism as claimed in claim 2, wherein said padlock hasp means includes a cut profile to allow multiple padlocks so as to block movement of said slider switch means that toggles between said AUTO, MANUAL and LOCK mode of operation.
4. The interlock mechanism as claimed in claim 3, wherein said locking means selected from padlock and/or key-lock, for locking said motor operators.
5. The interlock mechanism as claimed in claim 1, wherein said padlock-latch assembly further comprises one or more latch spring means.
6. The interlock mechanism as claimed in claim 5, wherein said hasp latch means (6) is guided symmetrically in groves on said housing and said housing cover, and thereby acts against said cam profiled protrusion of said padlock hasp means in lateral direction due to force from said latch spring means.
7. The interlock mechanism as claimed in claim 5, wherein said padlock hasp spring means and said latch spring means are compression type springs with sufficient guide ways on both ends.
, Description:TECHNICAL FIELD OF THE INVENTION

[001] The present subject matter described herein, in general, relates to electrical power switchgear with motor operators. More particularly, the invention relates to an interlock systems in the motor operators for the electrical switching devices.

BACKGROUND OF THE INVENTION

[002] Motor operators for power switches with a drive system facilitates switch operation by force either from the motor of the operator or such as manually applied force, even for switches at overhead (or pole-top) locations. These devices get mounted inside a board or panel board for added safety to the operator. Most often these devices are required to be operated either from outside or by opening the enclosure/ panel.

[003] Motor operators work on the simple philosophy of transmitting the power through motor to the gearing system, and from gearing system to the drive system which can either be a crank slotted lever mechanism or a rack and pinion arrangement which converts the rotary motion to reciprocating and eventually drive the knob of the electrical switching devices such as molded case circuit breakers (MCCB).

[004] Irrespective of the philosophy used, motor operators are equipped with safety interlocking mechanism to prevent inadvertent use of motor operator to switch ON of switch OFF the circuit breaker either electrically or manually. Typical scenarios are like preventing the switch ON (Contact closing) of circuit breakers when the associated electrical equipment is undergoing repairs, or replacement. Also interlocks are required to maintain non-intervened state retention of circuit breaker under supervision. Interlocking requirements differ according to global standards and market requirements, stringent amongst them are the NFPA requirements.

[005] Also in today’s scenario response time for an electrical switching system to switchover from one desired source to the other is gaining importance. Thus with a view of lesser operational time and remote operation and space of a switching device, direct driven type or stored energy type motor mechanism are used.

[006] Further, for some existing interlock systems in electrical switching devices, reference is made to US20130270076A1 which relates to a lockable manually-operated rotary actuator for electrical switching devices, such as motor protection circuit breakers or smaller circuit breakers.

[007] Reference is also made to US5467622A, which relates to a handle lock for reciprocally movable handle operated apparatus. More particularly it relates to a handle lock for a reciprocally movable handle of electrical switching apparatus, fluid valve apparatus and the like. Still more particularly this invention relates to padlock provisions for locking the handle in a predetermined operating position and still more particularly, locking the handle in the OFF position.

[008] Reference is made to US20120168287 A1, relates to a switching assembly having an interlock device for a selector switch is provided. The interlock device includes a flapper member rotatably coupled to a base member. The flapper member has an aperture disposed proximate to an aperture of a panel such that the selector switch extends through the apertures. The flapper member further includes an indented region and has a first operational position proximate to the panel and a second operational position disposed outwardly from the panel. When an arm portion of the selector switch is disposed within the indented region of the flapper member at the second rotational position and the flapper member is rotated to the second operational position, then the arm portion cannot be rotated outside of the indented region.

[009] Reference is made to US 6596952 B1, related to a rotary handle operator for a circuit breaker includes a lock plate having a live spring, formed as one piece with the lock plate, for biasing the lock plate in its unlocked position. With the lock plate in this unlocked position, rotation of the rotary handle operator's handle will actuate movement of a sliding member within the rotary handle operator, thereby moving the operating lever of the circuit breaker from its on position to its off position, and vice versa. When the rotating handle is in its off position, the lock plate may be pivoted against the bias of the springs so that the lock plate fits within a slot in the housing of the rotary handle operator, thereby resisting movement of the handle. In this position, an aperture dimensioned and configured to receive the shackle of a lock protrudes upward from the handle, permitting insertion of a lock to secure the lock plate in this locked position.

[0010] Reference is made to CN1598987 A that provides a closure assembly for a circuit breaker. The circuit breaker includes a housing built with separable contacts and an operating mechanism. The housing has a boss portion having an opening. A means for moving between open and close the separable contacts and protruding from the opening operation of the handle in the "on" (ON) and "off" (OFF) of the circuit breaker position. The locking assembly includes a pivotally attached to the handle and configured to operate the first and second locking member and the boss portion engages the circuit breaker housing so that when the lock shackle inserted into the first and second locking When the shackle member receiving hole, limits the operation lever from "on" (ON) or "off" Mobile (OFF) position.

[0011] Thus, in view of the existing interlocking systems of the electrical switching devices, the inventors of the present invention to provide an improved safety interlocking mechanism that are manually settable and can be achieved either by locking the switch parts by a key or equivalent removable member making use of a padlock, which ensures multi-level check for system safety.

SUMMARY OF THE INVENTION

[0012] 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.
[0013] An object of the present invention is to provide a compact interlocking mechanism for a switchgear motor operator, which ensures breaker state retention, inadvertent operation of motor operator, disabling electrical and manual operational mode, provision for 3 padlock and an optional key-lock

[0014] Another object of the present invention is to provide an interlocking mechanism with operator friendly interface having a slide-up latch and pop-up type padlock hasp, thus ensuring a prevention from tool abuse as in case of pull-out type padlock hasps.

[0015] Yet another object of the present invention is to provide an interlocking mechanism with a provision of auto retention by easy push-back of padlock hasp.

[0016] Still another object of the present invention is to provide an interlock assembly that forms a separate sub system of motor operators so that it can be accommodated in ant motor operator irrespective of whether the working philosophy of motor operator is stored energy , direct drive or solenoid operator type.

[0017] Accordingly to one aspect, the present invention provides an interlocking mechanism in motor operators for molded case circuit breakers (MCCB), wherein said mechanism comprising:
a mode selector assembly having a base and a slider switch means adapted to actuate or de-actuate one or more micro switches to make electrical connectivity or cut-off;
a padlock-latch assembly interacting with said mode selector assembly and being compacted in a housing with a housing cover, wherein said padlock-latch assembly comprises one or more padlock hasp means having a cam profiled protrusion, and at least one hasp latch means;
wherein during a LOCK mode operation enabled by said mode selector assembly, said padlock hasp means when enabled by said hasp latch means, pop-up due to spring action of at least one padlock hasp retention spring means, and allow a user to apply one or more locking means.

[0018] 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

[0019] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0020] Figure 1 shows the motor operator for a molded case circuit breaker, according to one embodiment of the present invention.

[0021] Figure 2 shows user interface of motor operator, according to one embodiment of the present invention.

[0022] Figure 3 shows internal architecture of safety interlock system for motor operators, according to one embodiment of the present invention.

[0023] Figure 4 shows Pop-out padlock latch enclosed in a housing, according to one embodiment of the present invention.

[0024] Figure 5 illustrates the internal construction of padlock-latch mechanism, according to one embodiment of the present invention.

[0025] Figure 6 shows padlock hasp means retained by spring loaded latch means, according to one embodiment of the present invention.

[0026] Figure 7 shows the mode selector assembly interacting with padlock–latch assembly, according to one embodiment of the present invention.

[0027] 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 OF THE PRESENT INVENTION

[0028] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0029] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0030] 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 invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0031] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0032] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0033] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0034] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0035] The present invention provides a switchgear motor operator having a compact interlocking mechanism which ensures breaker state retention, inadvertent operation of motor operator, disabling electrical and manual operational mode, provision for either one or maximum 3 nos. of padlock at a time and an optional key-lock.

[0036] In one implementation, padlock may be attached through the hasp in a position to block movement of a slider switch which toggles between three operational modes: - Auto (Electrically connected and no manual over-ride); Manual (Electrically disconnected and manually operable) and lock (both electrically and manually disconnected). Padlocking will be possible only in lock mode of the motor operator, thus assuring the workman of electrical disconnect while working on equipment in the downside until his padlock is removed and circuit breaker state is regained. The hasp generally will accept up to 3 nos. of shackles to allow individual workmen/ supervisors to apply their respective padlocks.

[0037] In one implementation, the figure 1 shows a direct drive type motor operator usually superimposed on a molded case circuit breaker for remotely operating the breaker.

[0038] In one implementation, the figure 2 shows the user interface on a typical direct drive motor operator which consists of an operating handle, toggle switch for changing the operating modes, Padlock and Key lock as safety Interlocks, an indication window for true breaker state indication and IP cover.

[0039] In one implementation, the figure 3 shows the internal architecture of safety interlock system for motor operator which consist of mode selector, padlock hasp means, housing and housing cover.

[0040] In one implementation, the figure 4 and 5 shows padlock hasp popped out due to hasp retention spring and supported in guides.

[0041] In one implementation, the figure 6 shows the padlock hasp means popped-in and retained by a spring loaded latch.

[0042] In one implementation, the figure 7 shows mode selector assembly with a micro-switch interacting with padlock-latch sub assembly.

[0043] In one implementation, as shown in figures 2-7, the components or the technical features of the present invention with their reference numerals are mentioned below:
1. Mode selector assembly
2. Key-lock
3. Padlock hasp
4. Hasp latch
5. Housing
6. Housing cover
7. Padlock hasp retention spring
8. Latch spring
9. Micro switch.

[0044] In one implementation, the interlock system consists of mode selector assembly (1) having a base and a sliding selector which actuates and de-actuates the micro-switch (9) used to make electrical connectivity and cut-off. There are three modes of operation: - a) AUTO MODE b) MANUAL MODE and c) LOCK MODE. These 3 modes are selected by the workman/ supervisor as per the requirements. If the motor operator is supposed to be operated remotely then, it can be set to AUTO mode. In case of manual intervention, MANUAL mode can be actuated, whereas in case of maintenance/ repairs or replacement, LOCK mode can be selected.

[0045] In one implementation, the padlocking will be possible only in LOCK mode and not in any other modes. This can be achieved by blocking the padlock hasp means (3) in AUTO and MANUAL mode by the mode selector assembly (1). Padlock hasp means (3) will include a rectangular cut to accept up to maximum of 3 padlocks so as to allow individual workmen to apply their respective padlocks.

[0046] In one implementation, referring to figure 3, which illustrates a padlock- latch sub-assembly, consisting of padlock hasp means (3), hasp latch means (4), housing (5), housing cover (6), padlock hasp retention spring means (7) and latch spring means (8). The padlock hasp means (3) can be guided symmetrically on two guides and will include a cam profiled protrusion. The padlock hasp (3) will always pushed up by padlock hasp retention spring (7), thus providing a pop-up action whenever it is de-latched. The padlock hasp retention spring means (7) can be housed on a circular protrusion in Housing (5).

[0047] In one implementation, the hasp latch means (6) can be guided symmetrically in groves on Housing (5) and Housing cover (6) and acts against the cam profiled protrusion in lateral direction ( perpendicular to padlock hasp retention spring ) due to force from latch spring means (8). Both padlock hasp spring means (7) and latch spring means (8) are compression type springs with sufficient guide ways on both ends and effect of buckling being restricted by the housing cover. Thus the latching and de-latching will take place in an enclosed housing in a very compact space.

[0048] In one implementation, whenever the workmen puts the unit in LOCK mode, Padlock hasp means (3) will be freed for pop-up action but do not pop-up instantaneously. It is only after sliding up the hasp latch (4) manually, the padlock hasp (3) pop–up due to spring action. Whenever the hasp latch (4) will slide up, the cam profiled protrusion on padlock hasp means (3) will be released and it moves in upwards direction. Once the padlock hasp means (3) pop-up, workmen can put the padlocks to lock-out the motor operator. In AUTO and MANUAL mode, Padlock hasp (3) can be arrested by the selector of mode selector assembly (1).

[0049] In one implementation, on pushing back the padlock hasp (3), the cam profiled protrusion slides over the spring loaded hasp latch (4) to the extent of its overlap. As soon as the overlap will be achieved, the hasp latch means (4) can be released back due to spring action and eventually arrests the padlock hasp (3) in spring loaded condition, thus keeping it ready to pop-up whenever the hasp latch (4) is slide – up by the workmen.

[0050] In one implementation, the padlock hasp means (3) sits flushed to the motor operator’s cover and guide ribs on the cover ensures a restriction against tool abuse to pull out the padlock hasp in any other modes.

[0051] Some of the noteworthy features of the present invention, are as follows:
• The interlock assembly consisting of mode selector sub-assembly and padlock-latch sub assembly interacts within itself and not any moving component (Gears or linkages) of the motor operator, thus ensuring circuit breaker state ( ON or OFF ) free padlocking.
• Padlock sub-assembly is compacted in a housing with housing cover, thus making it robust, less susceptible to system vibrations.
• Padlock sub-assembly is achieved with minimal interacting components.
• LOCK mode acts as separate mode of operation wherein, the motor operator can be padlocked and further key-locked by tripping the circuit breaker.
• Padlocking is possible only in LOCK mode with a secondary operation of sliding-up the hasp latch means, thus ensuring two level check for padlocking.
• Components does not interact with any dynamically moving components of motor operator, thus providing to accommodate the same philosophy in very least spaces for various size of motor operators.
• As interlock assembly forms a separate sub-system of motor operator, it can accommodated in any motor operator irrespective of whether the working philosophy of motor operator is stored energy , direct drive or solenoid operator type.

[0052] Some of the non-limiting advantages of the present invention, are as follows:
• The present invention provides a very compact way of interlocking in minimal space and methodology adaptive to any type and size of motor operator.
• Also, the invention provides operator friendly interface by having a slide-up latch and pop-up type padlock hasp, thus ensuring a prevention from tool abuse as in case of pull-out type padlock hasps.
• The present invention also provides auto retention by easy push-back of padlock hasp.
• The pad lock sub assembly of the present invention is compacted in a housing with housing cover thus making it robust and less susceptible to system vibrations
• The pad locking assembly of the present invention is achieved with minimal interacting components.
• Components of the present invention do not interact with any dynamically moving components of motor operator, thus providing to accommodate the same philosophy in very least spaces for various sizes of motor operators.
• Padlock hasp spring and latch springs of the present invention can be varied for different motor operators to vary the ease of operation.
• The complete assembly ensures an operational lockdown by electrical cut-off to motor operator and blocking the manual operation, thus ensuring the circuit breaker is not switched ON or switched OFF inadvertently if the workmen have padlocked the motor operator for safety purpose.

[0053] Although an interlocking mechanism in motor operators for molded case circuit breakers of the present invention have been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of interlocking mechanism in motor operators for molded case circuit breakers.