Claims:WE CLAIM:

1. A key interlock arrangement (100) to control access for shifting supply to circuit breakers (150A/ 150B), the key interlock arrangement (100) comprising:
• a casing (10) having a top side (4) and a bottom side (6), the top side (4) having a first slot (2) and a second slot (3) configured thereon;
• a first key lock (20) assembled into the first slot (2) of the casing (10) for being driven to any one of a locked position and an unlocked position;
• a second key lock (30) assembled into the second slot (3) of the casing (10) for being driven to any one of the locked position and the unlocked position;
• a first gear (40A) mounted on the first key lock (20) to assist the assembly of the first key lock (20) into the casing (10);
• a second gear (40A) mounted on the second key lock (30) to assist the assembly of the second key lock (30) into the casing (10), the gears (40A, 40B) being mounted and oriented in such a way to ensure locked position of the key lock (20/30) and unlocked position of the other key lock (30/20) at any given time;
• a cover (50) fitted on the bottom side of the casing (10), the cover (50) having a third gear (40C) mounted thereon to aid in direction change and shift the motion; and
• a plurality of fasteners (6) for fitting the cover (50) onto the casing (10),
wherein, when a key is inserted and rotated in any one of the key locks (20/30) from unlocked position to locked position, the gears (40A, 40B, 40C) are oriented in such a way to result in exact unlocked position of other key lock (30/20) thereby interlocking key locks (20, 30) at their exact locked and unlocked positions allowing supply to be shifted to any one of the circuit breakers (150A/ 150B).

Dated this 30th day of March, 2017
Priya Pandey
(Agent for Applicant)
IN/PA-2018
, Description:KEY INTERLOCK ARRANGEMENT TO CONTROL ACCESS FOR SHIFTING SUPPLY TO CIRCUIT BREAKERS

FIELD OF THE INVENTION

The present invention generally relates to a key interlock arrangement to control access for shifting supply to circuit breakers, and more particularly to the combination interlocking through key locks when two or more circuit breakers are used for incoming supply and only one has to be positively switched ON.

BACKGROUND OF THE INVENTION

In general, electrically operating mechanism is used in such cases where power transfer has to happen with the connection to load. Normal lines and emergency lines may or may not have similar voltages, frequencies and phases. Their electrical operating mechanism can vary according to their requirement. In the event of a power failure, a transfer switch is used with the electrically operating mechanism to automatically switch power supply from the normal line to the emergency line so as to maintain healthy supply during unavailability of current source. Applications for transfer switches include stand-by power supplies, multiple sources, Energy consumption and optimization.

Systems are always kept locked and only under supervision, the same can be accessed. When unit one with load has to be switched off and shifted to other supply, unit one has to be disconnected from the supply and the unit two can be made to connect with supply. This interlocking is used in all the locations where there are multiple power supply lines and shifting needs to happen. Each unit will have a specific lock position in which the unit is disconnected from the main supply and the key can be removed. The same key can be interlocked with the other unit which is in disconnected state at present, and can be used to shift the power supply.
In U.S. Patent 5581133, disclosed are a combination transfer and bypass isolation switch utilizing drawout protective devices and key interlocks. It discloses an apparatus that selectively connects a normal power line and an emergency power line to a load, and includes two interlocked switching mechanisms, each having individual interlocks, for selectively connecting the power lines to the load, and an interlock mechanism for interlocking the switching mechanisms in order that only one of the power lines at a time is connected to the load. The switching mechanisms may each have two drawout cassettes including associated switching device from at least one of the switched power lines and the load. Each switching device may be a circuit breaker having a trip unit for sensing current flowing from a power line to the load and tripping the circuit breaker. The interlock mechanisms may include key lock mechanisms which selectively disable closing of the switching devices. Each key lock mechanism may have individual locks on associated cassettes and a single key for operating only one of the locks. The individual interlocks of the switching mechanisms may cooperate with the key lock mechanisms to selectively disable connection of a power line to the load. Each key may be retained by an unlocked associated lock and may be removed from a locked associated lock.

In U.S. Patent 2012/0118711 A1, an undercarriage for use with a circuit breaker includes a bottom plate, a front beam removably coupled to the bottom plate via a screw, where in the lead screw is configured to engage with a threaded support that is coupled to the bottom plate to facilitate racking the circuit breaker in a switchgear. The undercarriage also includes a key lock assembly which in turn includes a lock and an interlock configured to couple to the lock such that the interlock is movable between a locked position and an unlocked position, wherein engagement of a racking handle with the lead screw is enabled when the interlock is in the unlocked position.

The above mentioned mechanisms require linkages to be done on the panel, involve multiple components at multiple levels to achieve the desired function and are highly operator dependent requiring high skill involvement.

Hence, there is a need of a compact key interlock arrangement to control access for shifting supply to circuit breakers by overcoming the above mentioned drawbacks of the prior art.

OBJECTS OF THE INVENTION

An object of the present invention is to provide quick interlock solution without interrupting the current panel assembly and structure.

Another object of the present invention is to provide cost-effective compact lock assembly with electrician level interpretation skills to operate.

Still another object of the present invention is to solve the problem of interlocking two different makes or voltage subsystems at any time and at any level.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a key interlock arrangement to control access for shifting supply to circuit breakers. The key interlock arrangement comprises a casing, a first key lock, a second key lock, a first gear
a second gear, a cover and fasteners.

The casing includes a top side and a bottom side. The top side includes a first slot and a second slot configured thereon.

The first key lock is assembled into the first slot of the casing for being driven to any one of a locked position and an unlocked position. The second key lock is assembled into the second slot of the casing for being driven to any one of the locked position and the unlocked position.

The first gear is mounted on the first key lock to assist the assembly of the first key lock into the casing. The second gear is mounted on the second key lock to assist the assembly of the second key lock into the casing. The gears are mounted and oriented in such a way to ensure locked position of the one of the key locks and unlocked position of the other key locks at any given time.

The cover is fitted on the bottom side of the casing. The cover includes a third gear mounted thereon aid in direction change and shift the motion. The fasteners are adapted for fitting the cover onto the casing.

When a key is inserted and rotated in any one of the key locks from unlocked position to locked position, the gears are oriented in such a way to result in exact unlocked position of other key lock thereby interlocking key locks at their exact locked and unlocked positions allowing supply to be shifted to any one of the circuit breakers.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawings:
Figure 1 shows a key interlock arrangement to control access for shifting supply to circuit breakers, in accordance with the present invention;

Figure 2 shows a lock subassembly of the key interlock arrangement of figure 1; and

Figure 3 show an exploded view of the key interlock arrangement of figure 1.
DETAILED DESCRIPTION OF THE INVENTION

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a key interlock arrangement to control access for shifting supply. The present invention provides quick interlock solution without interrupting the current panel assembly and structure, provides cost-effective compact lock assembly with electrician level interpretation skills to operate as well as solves the problem of interlocking two different makes or voltage subsystems at any time and at any level.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.

Referring to figures 1-3, a key interlock arrangement (100) to control access for shifting supply to circuit breakers (150A/150B) in accordance with the present invention is shown. The key interlock arrangement (100) is a lock assembly that comprises a casing (10), a first key lock (20), a second key lock (30), a first gear (40A), a second gear (40B), a cover (50) and a plurality of fasteners (60).

The casing (10) is a lock casing. The casing (10) includes a top side (4) and a bottom side (6). The top side (4) includes a first slot (2) and a second slot (3) configured thereon as shown in figure 3.

The first key lock (20) is assembled into the first slot (2) of the casing (10) for being driven to any one of a locked position and an unlocked position. Similarly, the second key lock (30) assembled into the second slot (3) of the casing (10) for being driven to any one of the locked position and the unlocked position. Specifically, the key locks (20, 30) are assembled on the top side (4) of the casing (10) along with the gears (40A, 40B) to form a compact arrangement. In an alternate embodiment, the key interlock arrangement (100) can include multiple key locks of same or different construction that can be assembled in multiple slots of the top side (4) of the casing (10).

The first gear (40A) is mounted on the first key lock (20). The first gear (40A) is adapted to assist the assembly of the first key lock (20) into the casing (10). The second gear (40B) is mounted on the second key lock (30). The second gear (40B) is adapted to assist the assembly of the second key lock (30) into the casing (10). The gears (40A, 40B) has an idler gear/ third gear (40C) in-between based on the calculation that the first key lock (20) and the second key lock (30) are based on the lock and unlock stable states. The gears (40A, 40B) are mechanical elements mounted and oriented on the key locks (20, 30) in such a way to ensure locked position of the one key lock (20/30) and unlocked position of the other key lock (30/20) at any given time. Thus, the arrangement of the gears (40A, 40B, 40C) is in such a way that one of the key lock (20/30) will always be in locked and other key lock (30/20) will always be in unlocked position. Thus, the same gears (40A, 40B, 40C) are repeated and placed in particular orientation to result in exact lock and unlock position combinations of the multiple key locks.

The cover (50) is fitted on the bottom side (6) of the casing (10). The cover (50) includes the third gear (40C) mounted thereon as shown in figure 3. The third gear (40C) is adapted to aid in direction change and shift the motion. The plurality of fasteners (60) is adapted for fitting the cover (50) onto the casing (10). Thus, the casing (10) on the bottom side (6) is closed with the cover (50) with the help of plurality of mechanical fasteners (60).

Once the key is inserted and rotated in any one of the key locks (20/30) from unlocked position to locked position, the gears (40A, 40B, 40C) are oriented in such a way to result in exact unlocked position of other key lock (30/20), thereafter the key is removed thereby interlocking the key locks (20, 30) at their exact locked and unlocked positions allowing supply to be shifted to any one of the circuit breakers (150A/ 150B). This is further described herein below:

Condition 1:
Supply from Unit 1/circuit breaker (150A):
• The key from the first key lock (20) is placed in Unit 1 i.e. the circuit breaker (150A). Unit 1 is ON and main supply is ON. In this case, the key from the second key lock (30) is present in the lock sub-assembly.
• In order to shift the supply from Unit 1 to Unit 2 i.e. from the circuit breaker (150A) to the circuit breaker (150B), the key is removed only from Unit 1 to switch OFF the Unit 1 but the key cannot be removed from the other units. This ensures positive locking of the circuit breaker (150A). Thus, the shifting of supply is done with single key and when the key is available from the existing unit.
• When the key from the first key lock (20) of Unit1 is inserted into lock subassembly and rotated, the key present in the second key lock (30) can be taken out.
• Now the key of the second key lock (30) can be inserted into Unit 2 for switching ON the circuit breaker (150B). In all other cases, Unit cannot be switched ON. Thus ensuring positive locking.

Condition 2:
Supply from Unit 2:
• Key from the second key lock (30) is placed in Unit 2 i.e. the circuit breaker (150B). Unit 2 is ON and main supply is ON. In this case, the key from first key lock (20) is present in the lock sub-assembly.
• When supply has to be shifted from Unit 2 to Unit 1 i.e. from the circuit breaker (150B) to the circuit breaker (150A), the key is removed only from Unit 2 to switch OFF the Unit 2 but the key cannot be removed from the other units. This ensures positive locking of the circuit breaker (150B).
• When the key from the second key lock (30) of Unit 2 is inserted into the lock subassembly and rotated, the key present in the first key lock (20) can be taken out.
• Now the key of first key lock (20) can be inserted into unit 1 for switching ON the circuit breaker (150A). In all other cases, Unit cannot be switched ON. Thus ensuring positive locking.

ADVANTAGES OF THE INVENTION

1. The key interlock arrangement (100) is a compact arrangement involving less number of components.
2. The key interlock arrangement (100) is capable of being retrofitted with the existing panel setup or placed on the panel at any convenient available location based on the panel builder.
3. The key interlock arrangement (100) is capable of being installed without hampering the power units.
4. The key interlock arrangement (100) is capable of being interlinked with any kind of key locks.
5. The key interlock arrangement (100) is capable of being multiplied based on number of units to be interlocked.
6. The key interlock arrangement (100) achieves positive locking with the circuit breakers (150A, 150B) and ensures protection at all times.
7. The key interlock arrangement (100) can be sold as an individual unit either to be coupled with the incomer interlock or outgoing load interlock.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.