FIELD OF THE INVENTION
The present invention relates to tamper-proof energy management systems. More particularly, it relates to a lock and seal assembly provided for locking the maximum demand (MD) reset push button of electric meters once the MD has been set, wherein said mechanism includes a sealing assembly comprises of a MD reset push button and a slide fit sealing provision that engages the MD reset push button to limit its operation in sealing mode and thereby, avoiding any unwanted activity, preferably tampering.

BACKGROUND OF THE INVENTION
Generally, energy meters are provided with sealing provisions for MD reset push button to protect any unauthorized activity in the meter called tampering. The main objective of sealing any device is to ensure that access to certain sensitive parts of the device is restricted. This is especially so where energy meters are concerned, since energy meters form the basis from which revenue is obtained by the electricity supply utility. It is therefore imperative that strict sealing standards are established and that proper control is maintained to ensure that the requirements are adhered to.
A common type of demand meter currently in use by the electric utility industry is a conventional watt-hour meter mechanism, used in combination with a timing element, to sum up the kilowatt hours of energy measured by the watt-hour meter in a pre-selected time span called a demand interval. Usually a demand interval of 15 or 30 minutes is selected for such meters. In order to indicate the maximum power demand on a customer's system in a given billing period, such as during a one month span, an indicating mechanism, such as a demand register indicator, is incorporated in all demand meters. At the end of billing period, a bill is generated considering the total energy consumption and the maximum demand value of billing period. Once the bill is generated, the maximum demand value is reset by authorized person. The maximum demand value has very critical role in controlling and determining power consumption by consumers and hence, manufactures provide some protection means in order to avoid any unauthorized operation or tampering.
Maximum demand (MD) is the power consumed over a predetermined period of time. This power is calculated and billed by a kW demand meter, which records the highest kW value in specified period of time. The maximum demand values are required in order to penalize the customer if one withdraws a power more than the sanctioned power.
Sometimes, consumers want to reset maximum demand value at your own in order to avoid from being penalized due to unauthorized power consumption. Hence, sealing features are needed to avoid any tampering. One of the most common methods is to provide a hole on the push button and corresponding hole on top cover through which a steel wire with plastic/lead seal is passed and locked. This limits the movement of the push button from moving downwards and pressing the key. This condition is considered to be sealed condition. However, the conventional method of sealing the push button has many shortcomings. Since the push button is limited in movement only axially, upon hard pressing, requires additional components which increase the cost. In such type of sealing, the sealing wire is prone to loosen. As a result, the MD reset push button can be easily operated in sealing mode which leads to tampering. The sealing provisions provided by the authorities have some limitations and hence, newer approaches are needed to overcome such limitations.
It is clearly essential that only the meter reader can operate the MD reset push button, and to this end, present MD reset push button usually have a sealed wire passing through them when in their "unpressed" state, which wire has to be unsealed and removed before the MD reset push button can be pressed to effect its reset function. Since the sealed wire can only be fitted by the meter reader or other authorised person, any damage to the wire or its seal is evidence of possible tampering with the MD reset push button.
In IN2013MU01088, a system is provided for locking and sealing arrangement for push button of electronic energy meters. The arrangement comprises a push button having two tabs projecting out in opposite directions, and at least one sealing hole configured thereon. Further, the arrangement comprises a top cover capable of receiving the tabs of the push button and a hole aligning with sealing hole on the push button. The top cover engages with a self locking means of the push button. A spring is positioned between the push button and the top cover to retract the push button when pressed. The arrangement further includes a wire with seal to be passed through the sealing hole of the push button and the hole of the top cover to prevent the rotation of the push button.
In GB2311655A, a system is provided for push button assembly used as a maximum demand indication reset button in a polyphase electricity meter, comprises a push button mounted in a housing which is moulded integrally with the front face of the meter. The push button is rotatable in the housing between a first rotary position in which it can be pushed into the housing against the action of a spring to operate a switch, and a second rotary position in which the push button is prevented from moving into the housing. The push button has a circular head with integrally moulded spring fingers and a central switch-operating stem projecting from its underside, the stem being axially split to form spring legs having outwardly projecting feet which lock the push button in the housing. The underside of the head also has a diametrically extending web, which aligns with and can move into a corresponding recess in the housing only when the push button is in the first rotary position. To prevent unauthorised use of the push button whilst in its second position, the push button and housing have apertures for receiving a wire.
In the cited prior art the patents provide sealing wire and spring based protection for maximum demand reset push button. This sealing wire and spring are prone to loosen, as a result, the MD reset push button can be easily operated in sealing mode which leads to tampering. Further, additional supporting components are required which again increases the cost as well as complexity of the invention.
Hence, there is a need of effective and secured sealing provisions for the protection of MD reset push button of the energy meter, which overcomes drawbacks of the prior art. Further, there is a need of durable sealing provisions that can protect MD reset push button for a period of long time.

OBJECT OF THE INVENTION
The main object of this invention is to provide a lock and seal mechanism for MD reset push button of electric energy meters.
Yet another object of the present invention to provide a lock and seal assembly to prevent tampering or operation of MD reset push button by any unauthorized person.
Yet another object of the present invention is to provide a sealing mechanism that includes a sealing assembly comprises of MD reset push button and a sliding fit sealing provision for securely locking and sealing the MD reset push button.
Yet another object of the present invention is to provide a full proof lock and seal mechanism that completely prohibits the operation of the MD reset push button in sealing mode.
Yet another object of the present invention is to provide a novel sealing assembly that provides an advantage over traditional sealing means wherein the sealing means are prone to loosen on frequent use and become insufficient to provide protection to MD reset push button.

SUMMARY OF THE INVENTION
In light of the shortcomings of the state of the art, the present invention provides a lock and seal mechanism for MD reset push button of electric energy meters. The lock and seal mechanism of the present invention includes a sealing assembly comprises of MD reset push button and a slide fit sealing provision for securely locking and sealing the MD reset push button.
According to another embodiment, the present invention provides a lock and seal mechanism for MD reset push button in electric energy meters comprising: a lock and seal assembly for maximum demand (MD) reset push button in an electric energy meter, said lock and seal assembly comprising: at least one umbrella shaped MD reset push button located on the electric energy meter for changing/resetting maximum energy demand values; at least one sealing component, having a first end and a second end, said first end located laterally under the MD reset push button, exhibiting lateral movement to allow MD reset push button to be pushed and reset maximum demand values; and a locking means integrated at the second end of the sealing component that permanently locks the slidable sealing component thereby restricting movement of the sealing component and MD reset push button; wherein pressing the MD reset push button moves the slidable sealing component away from the MD reset push button thereby allowing the MD reset push button to move down and reset to rest the maximum demand values; releasing the MD reset push button moves the slidable sealing component back in contact with the MD reset push button; and engaging the locking provision integrated at the second end of the sealing component, permanently locks the slidable sealing component thereby restricting movement of the sealing component and MD reset push button and hence avoid tampering.Thus the proposed lock and seal assembly is not reusable and needs to be completely replaced once sealing component is broken.
In yet another embodiment, the sealing assembly has special geometry that allows it to engage and/or disengage with the MD reset push button and thereby, defining two positions i.e., locking and unlocking position; and the slide fit sealing provision comprises a sealing component that can be slidably moved towards the locking position wherein the sealing component engages the MD reset push button and blocks its functionality in sealing mode. In this manner, the sealing mode provides a tamper proof property to the MD reset push button and prohibits reset operation by any person who is not authorized to do so. In case, wherein MD reset push button activity is needed, an authorized person move sealing component towards the unlocking position, wherein the sealing component disengages the MD reset push button and reached again to an operational state.
In another preferred embodiment, the present invention provides a method for lock and seal mechanism for MD reset push button in an electric energy meter comprising the steps of: resetting the maximum demand values; sliding the step shaped slidable sealing component backwards and restricting the movement of step shaped slidable sealing component ; and engaging the sealing means to lock the slidable sealing component thereby permanently blocking the movement of step shaped slidable sealing component.
In yet another embodiment, the present invention is more advantageous, because it is cost effective, more durable and secured tamper proof lock and seal mechanism which is achieved by completely avoiding sealing wire or spring in the invention.

BRIEF DESCRIPTION OF THE DRAWING
A complete understanding of the system and method of the present invention may be obtained by reference to the following drawings:
Figure 1A is a schematic view of traditional sealing provisions of MD reset push button available in the prior art;
Figure 1B is a schematic view of sealing provisions of MD reset push button available in the prior art;
Figure 1C is a schematic view of sealing provisions of MD reset push button available in the prior art;
Figure 2 is a schematic view of sealing assembly provided to lock and seal the MD reset push button as per the present invention;
Figure 3 is a top view of the sealing provision according to an embodiment of the present invention;
Figure 4A and 4B elucidate a lock and seal condition wherein MD reset push button is in non-operational state; and
Figure 5A and 5B elucidate unlocking condition wherein MD reset push button is in operational state.

DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Figure 1A, 1B and 1C are traditional sealing provisions that have been used in electric meters as per current state of the art. Generally, such sealing are done using a sealing wire that are prone to loosening after a specified period of time. Sometimes, such types of sealing are unable to provide full protection to the MD reset push buttons. In other words, MD reset push buttons are operable even in sealing mode.
Referring to Figure 2, a lock and seal mechanism according to the present invention is explained. In this embodiment, a sealing assembly 111 is provided with a MD reset push button and a slidably moving sealing component 311. The slidably moving sealing component 311 can easily engage or disengage the MD reset push button 211 to lock and unlock said MD reset push button 211 respectively.
In a preferred embodiment of the present invention is proposed a lock and seal mechanism for MD reset push button 211 in electric energy meters comprising: a lock and seal assembly for maximum demand (MD) reset push button in an electric energy meter, said lock and seal assembly comprising: at least one umbrella shaped MD reset push button 211 located on the electric energy meter for changing/resetting maximum energy demand values; at least one sealing component 311, having a first end and a second end, said first end located laterally under the MD reset push button, exhibiting lateral movement to allow MD reset push button 211 to be pushed and reset maximum demand values; and a locking means 411 integrated at the second end of the sealing component 311 that permanently locks the slidable sealing component 311 thereby restricting movement of the sealing component 311 and MD reset push button 211; wherein pressing the MD reset push button 211 moves the slidable sealing component 311 away from the MD reset push button 211 thereby allowing the MD reset push button 211 to move down and reset to rest the maximum demand values; releasing the MD reset push button 211 moves the slidable sealing component 311 back in contact with the MD reset push button 211; and engaging the locking provision 411 integrated at the second end of the sealing component 311, permanently locks the slidable sealing component 311 thereby restricting movement of the sealing component 311 and MD reset push button 211 and hence avoid tampering.
In another preferred embodiment of the present invention is proposed a method for lock and seal mechanism for MD reset push button 211 in an electric energy meter comprising the steps of: resetting the maximum demand values; sliding the step shaped slidable sealing component 311 backwards and restricting the movement of step shaped slidable sealing component 311; and engaging the sealing means 411 to lock the slidable sealing component 311 thereby permanently blocking the movement of step shaped slidable sealing component 311.
Referring to FIG 3, a top view of sealing provision 411 as per the present invention is explained. In this embodiment, the MD reset push button 211 is sealed completely means to restrict slidably moving sealing component 311.
Figure 4A & 4B, a lock and seal condition wherein the sealing component 311 is slidably moved towards the MD reset push button 211 to attain a locking position 511 wherein the sealing component 311 completely engages the MD reset push button 211 in such a manner the reset button cannot be operated.
Referring to Figure 5, elucidates the unlocking position as per the present invention. In this condition, the sealing component 311 is moved in outward direction i.e., away from the MD reset push button 211 that causes disengagement of sealing component 311 and the MD reset push button 211. In this way, the MD reset push button 211 regains its functionality and MD reset push button 211 activity can be carried, whenever needed.

We claim:
1. A lock and seal assembly for maximum demand (MD) reset push button in an electric energy meter, said lock and seal assembly comprising:
at least one umbrella shaped MD reset push button 211 located on the electric energy meter for changing/resetting maximum energy demand values;
at least one sealing component 311, having a first end and a second end, said first end located laterally under the MD reset push button, exhibiting lateral movement to allow MD reset push button 211 to be pushed and reset maximum demand values; and
a locking means 411 integrated at the second end of the sealing component 311 that permanently locks the slidable sealing component 311 thereby restricting movement of the sealing component 311 and MD reset push button 211;
wherein
pressing the MD reset push button 211 moves the slidable sealing component 311 away from the MD reset push button 211 thereby allowing the MD reset push button 211 to move down and reset to rest the maximum demand values;
releasing the MD reset push button 211 moves the slidable sealing component 311 back in contact with the MD reset push button 211; and
engaging the locking provision 411 integrated at the second end of the sealing component 311, permanently locks the slidable sealing component 311 thereby restricting movement of the sealing component 311 and MD reset push button 211 and hence avoid tampering.
2. The lock and seal assembly as claimed in claim 1, wherein the MD reset push button is made up of polymer or metal or combinations thereof.

3. The lock and seal assembly as claimed in claim 1, wherein the sealing component is made up of polymer or metal or combinations thereof.

4. The lock and seal assembly as claimed in claim 1, wherein the tamper proof sealing wire or spring are not required.

5. A method of utilizing a tamper proof lock and seal assembly, said method comprises the steps of:

a) resetting the maximum demand values;
b) sliding the step shaped slidable sealing component 311 backwards and restricting the movement of step shaped slidable sealing component 311; and
c) engaging the sealing means 411 to lock the slidable sealing component 311 thereby permanently blocking the movement of step shaped slidable sealing component 311.