SI25560A - Sensor key for detecting the opening of the electric meter cover - Google Patents

Abstract

The object of the invention is a sensor key (3) for detecting the opening of the electric meter cover located inside the electrical energy meter and detecting the opening of the meter cover. The closed, metrologically controlled meter cover holds the key (3) in the pressed, electrically open state, when the key is opened, the key (3) electrically contacts the contact surfaces (42 ') and (42 ") on the printed circuit board (4) and The key (3) according to the invention consists of a housing (1) and a contact spring (2) inserted thereon. The insertion of the key (3) inside the meter is carried out in such a way that the composite key (3) is only pushed in the openings (41 ') and (41') of the printed circuit (4) of said counter, the locking tabs (11 ') and (11') disable the key extraction (3). The non-activated key (3) provides a contact spring ) pressing the tabs (11 ') and (11 ") and the contact portions (23') and (23") to the two contact surfaces (42 ') and (42 ") respectively.

Description

Sensor key for detecting the opening of the electric meter cover

The invention relates to the detection of an unauthorized invasion of the electricity meter, more specifically the detection of the opening of any cover of the electric meter.

The electric meter is a metrologically certified measuring instrument for measuring the consumed electricity at the point of purchase. The meter housing is therefore stamped with calibration and distribution seals in order to detect possible countermeasure on the meter when reading the meter, which may result in an impact on the metrological operation of the meter, such as certified measuring devices or direct theft of electricity, for example by bridging power leads. Such unauthorized interventions are most often associated with the opening of the lid or covers of the meter and result in a loss of earnings of the electrical distribution, damage to the device, and / or serious injury to persons. In the past, electric meters were electromechanical and the state of consumption was read by the authorized person when visiting the site. At that time, this person also checked the state of the seal and the counter of the counter if there was an unauthorized intrusion into the counter. Today, counters are mostly electronic, and are mostly equipped with communication channels for data transmission on energy consumption in the clearing center of the electricity distribution company. In this case, there is no personal control over the situation of the site.

There are several possible solutions for controlling unauthorized interference in the surroundings of the meter, such as: measuring and adapting currents in individual power lines and in a zero conductor, detecting the presence of an external magnetic field, measuring the elevated ambient temperature, and the like. Unauthorized interventions are most often associated with the opening of the meter's cover. Traditionally, the counters were protected by a seal between the bottom and the meter cover. The seizure of the seal was an improper intervention. Modern electronic meters have a processor unit that can record an attempt at unauthorized encoding into a counter and communicate it to the center via a communication module. In addition, the covers of these counters are usually closed by locking mechanisms which, when unauthorized opening of the cover breaks, or locks themselves locally. In principle, it would be possible to repair or replace the lid after this operation in order to hide the consequences of intrusion.

Therefore, there is a need to detect any opening of the electric meter covers even if the consequences of unauthorized intervention were subsequently hidden. Such an event should be transmitted to the power distribution control center or permanently recorded in the meter. The sensor for detecting the opening of the lid must be installed inside the meter, it must function reliably and be cost-effective.

The requirement to install a sensor for detecting the opening of the lid inside the meter, rather than the lid itself, is the result of the meter manufacturing technology, where the sensor must be tested together with the detection system and the registration of the opening of the lid before the final closure of the meter. Modern meters are designed so that the meter cover is irreversibly placed on the bottom of the meter in such a way that it can be secured by locking elements that break apart when the cover of the meter is opened. Therefore, it is not possible to selectively test the system for detecting the opening after the meter is closed.

The operation of the sensor for detection further must not constitute an electrical load for the electric meter in the event of a power failure and must not increase its own consumption of the meter in the normal operation of the meter.

The detection sensor must also function reliably in terms of immunity to the tolerances of the assembly of the electric meter, temperature elongation and / or vibration, and the mechanical overrun of the meter housing, which can occur in the process of mounting the meter to the point of purchase.

The electrical meter is often installed in cabinets outside the building, where it is exposed to atmospheric influences. Therefore, the sensor for detecting the opening of the meter cover must be corrosion-resistant.

According to the international classification, the invention is classified in class G01R 11/24.

A technical problem solved by the invention is to propose a functionally reliable and cost-effective sensor device which will allow detection of the opening of the electric meter cover which will be installed inside the meter independently of the meter cover and will be corrosion-resistant.

A technical solution known in EP 1 431 766 BI is known, wherein the rotary sensor is a rotary wheel with asymmetric stoppers, wherein said wheel touches the meter cover and rotates for the incremental angle at the opening, but not when the meter cover is closed again. According to the proposed solution, the axis of said rotating wheel is connected to the rotary capacitor plate or the adjustable potentiometer electrically connected to the detection circuit. The disadvantage of the proposed solution is many components that increase the device for detecting the opening of the lid.

The solution is also proposed in WO 97 09 623, where the detection is carried out with a system of switches under the meter cover. The disadvantage of the solution is a large number of electronic components and the fact that the opening of the lid is detected only when the supply voltage is present.

A similar solution, which is not suitable for the said application due to energy consumption and a greater number of components, is also disclosed in US Patent Application No. 6,054,930. In patent application US20150377927A1, a detection device is proposed which includes a contact sensor consisting of a lever system of a dedicated a casing, a spring, a guided piston, and an electrically conductive contact polymer. The sensor described in this document is located inside the counter, and is activated by a plug placed on the inside of the meter cover at the turn of this cover. The solution described is intended for the specific execution of the electric meter, where the cover is screwed onto the meter housing. The average expert in this field would be able to process the described sensor for detecting the opening of the lid, which is mounted on the housing of a counter with a translatable displacement. The proposed sensor has this disadvantage that due to many components it is costly unfavorable.

The inductive sensor, as proposed in US20150226769A1 patent application, in addition to detecting the opening of the meter cover, also detects the presence of an external magnetic field and an elevated ambient temperature. The disadvantage of the proposed solution is that it requires a sophisticated detection circuit and a complicated sensor control process, which in any case justifies the purpose of the entire detection of the effect on the meter, but exceeds the requirement for a simple detection of the meter cover opening. Consequently, the described sensor is prone to annoying. A further problem is the durability of the sensor magnetization. The magnetized materials contain oriented magnetic domains, which represents the excited energy state of the material. Over time and due to the influence of temperature, vibration and / or the presence of a weak magnetic field in the environment, such materials are degraded and the said sensor loses functionality or at least reliability of operation. According to the proposed solution, this proposed problem can be solved by the occasional magnetization of the sensor through the detection circuit, but such a solution means an increased consumption of the meter in the state of storage, where the counter is supplied with an internal battery and is subject to conditions increasing temperature and vibration during transport, operation.

A possible solution, known from the art, is also the use of commercially available switching keys or microscopes which are unsuitable for solving said technical problem due to:

Too high, that's more than 4mm, which is the technological limit for soldering; otherwise, selective soldering is required, which considerably increases the production process of the meter; and / or

Selective THT (through the hole) soldering technology in the case when the THT type switch is located on a printed circuit where the other THT elements are located exclusively on the opposite side of the printed circuit board (PTIV); and / or

The total key stroke is too small; and / or

Understeer of the hysteresis of the working displacement of the button, which consequently means unreliable overlaps due to the tolerances of the manufacture of the mechanical composition of the counter, temperature extensions, vibrations or deformations of the casing of the meter, which may occur at assembly at the point of purchase; and / or

Lack of switching forces required to move potential plastic levers or pistons to the base position. - There are no suitable switches on the market that would be electrically disconnected in the active state.

The examples described, and so far in practice, the known solutions do not solve the technical problem, as they are either functionally inadequate or costly unfavorable.

According to the invention, the technical problem is solved by using a dedicated sensor key, which is made of curved, electrically conductive and corrosion-resistant spring sheets, whereby, according to the invention, the button is inserted and snapped into the opening of the printed circuit board, which is located inside the meter casing and on which the contact surfaces are located. In the following, the invention will be explained in detail on the basis of the description of the embodiments and by the drawings illustrating: FIG. 1: Sensor button in the assembly Fig. 2: Sensor button housing Fig. 3: Touch spring sensor contact spring

Fig. 4a: Detail with openings and contact surface on PTIV Fig. 4b: Cross-section of PTIV in the area of contact surfaces and openings

Fig. 5a: The cross-section of the key before inserting into the PTIV

Fig. 5b: The cross-section of the key after stopping in PTIV

Fig. 5c: Longitudinal section of the key after insertion in PTIV Fig. 6: The cross-section of the button in the pressed state

DESCRIPTION OF THE INVENTION

The sensor key 3 according to the invention consists of two basic components: housing 1 and contact spring 2, as shown in Figure 1. The housing 1 of the invention is characterized in that it has essentially the U-shape formed by two flat side members 14 'and 14' and the upper part 15, as shown in Figure 2. On the side sections 14 'and 14', the tabs 11 'and 11' are directed towards the upper part 15 of the housing 1 and according to the invention are bent towards the interior of the housing 1 buttons. The lower edges of the 14 'and 14 "side members are bent outwardly in the middle portion so as to form the input conical surfaces 16 ' and 16 '.

Figure 3 shows the contact spring 2 of the invention, which is designed to include the upper part 21 and the side panels 22 'and 22 "which are provided by the spring spring of the contact spring 2 in the vertical direction and the required working stroke of the key 3 is required. The spring 2 is symmetrical to the vertical axis 24 which is perpendicular to the part 21. The side portions 22 'and 22' are, according to the invention, on the lower contact portion 23 'and 23' are curved in such a way as to provide a good and reliable electrical contact with the contact surface 42 ' is located on the printed circuit board 4 (PTIV) shown in FIG. 4. The contact portions 23 ' and 23 ' are curved semi-circular and without a sharp edge in order to push the contact surface 42 'at the press of the button 3. This eliminates the potential oxides and impurities on the surface 42 'to improve the electrical contact. In the particular embodiment, the side portions 22 'and 22' may be asymmetrical with respect to the vertical axis 24, in order to provide different forces of the two contact portions 23 ' ' ' ' ' and 23 " on the contact surface 42 '. The width of the contact spring 2, the width h2 of the spring 2 is greater than the internal width of the HI of the housing 1. The button 3 of the invention is assembled in such a way that the contact spring 2 is inserted into the housing 1 in such a way that the upper part 21 of the contact spring 2 fits on the inner surface of the upper part 15 of the housing 1. at the entrance of the housing 1, through the conical surfaces 16 'and 16 ", the tooth plates 14' and 14" are deflected apart, thereby allowing the spring 2 to be placed in the housing 1. When the key 3 consists of a tooth 211 and 212 locks for tabs 12 'and 12'. The openings 25 of the springs 2 and 13 of the housing 1 are designed to facilitate the positioning of both components 1 and 2 when assembling the key 3 in such a way that they engage in a pin that is positioned in the device for assembling the key 3.

The composite key 3 according to the invention is inserted in the openings 41 'and 41' in the PTIV 4 as shown in Figure 5a. The extensions 17V, 171 ", 172" and 172 "limit the movement of the key, in the final position encountering the PTIV 4. With the travel limit, the possibility of damage to the contact spring 2 is prevented due to overload, either during operation or during installation. The upper 42 'and lower 42' contact surfaces are shown longitudinally between the openings 41 'and 41', as shown in Figure 4. The insertion procedure of the key 3 in PTIV 4 is shown in the cross-sections in Figure 5. The function of the key 3 is to electrically terminate the contact surfaces 42 'and 42 ". After inserting the button 3 according to the invention in the openings 41 'and 41', the tabs 11 'and 11' are locked under PTIV 4, the contact spring 2 is pushed by the housing 1 of the key 3 of the invention upwards so that the contact portions 23 'and 23' of the contact spring 2 pressing the contact surface 42 ', the tabs 11' and H 'being pressed onto the lower contact surface 42 "PTIV 4. The position of the inserted, inactivated key 3 of the invention is shown in Figs. 5b and 5c in both cross sections. The contact spring 2 in to its upper part 21 due to the pressure on the lower surface of the upper part 15 of the housing 1, creates an electrical contact between the contact spring 2 and the housing 1 of the key 3 of the invention. Thus, the contact surfaces 42 'and 42 "are electrically closed. The contact surfaces 42 'and 42' are electrically in contact with the detection circuit on the PTIV 4. The simplest implementation of the detection circuit is the use of the input of an existing control circuitry of the electric meter, the change in the voltage state being the detection of the change in the status of the key 3 of the invention.

The activation of the key 3 according to the invention is carried out with the vertical force F, as shown in Figure 6. The key 3 moves in the direction of force F, thus performing the working stroke. In this case, the tabs 11 ' and H ' lose electrical contact with the lower contact surface 42 ' When the electric meter cover is closed, it presses the button 15 directly or via the lever, and therefore, when the meter is closed, the detection circuit does not consume energy.

The key characteristic of the key 3 according to the invention is the double electrical contact formed by the two contact portions 23 'and 23' of the contact spring 2 with the upper contact surface 42 'and the double electrical contacts formed by both the tabs 11' and 11 'of the housing 1 with the lower contact surface 42. The advantage of such a design of the key 3 of the invention is a reliable contact.

The contact force F of the key 3 of the invention is provided with the elastic properties of the material from which the contact spring 2 is made and with its shape. The proposed material for the contact spring 2 according to the invention is beryllium bronze, but another metal material of similar mechanical properties may also be used. In a special embodiment according to the invention, the contact spring 2 is surface-protected with a thin layer of a corrosion-inerted metal such as nickel, silver, gold or the like. This ensures the life of key 2 in the environmental conditions in which the meter operates and good electrical conductivity.

The elasticity of such contact spring does not change during the lifetime and operating conditions of the meter due to the viscoelasticity of the soft metal materials and elastomers, this is not true. With the proposed key 3 according to the invention, the required large contact force F is reached, the required working stroke of the key, which is larger from lmm and the excessive stroke of the button after the electrical contacting of the contacts exceeding 0.5 mm.

The housing 1 of the key 3 of the invention is made of conductive metal, which has good electrical conductivity, is corrosion resistant to the humid environment and has high mechanical strength, such as stainless steel, brass and bronze. According to the invention, a new silver is proposed. In a special embodiment according to the invention, anticorrosion protection of the housing 1 of the key according to the invention 3 is proposed with a thin layer of a corrosion-inerted metal such as nickel, silver, gold or the like.

The proposed embodiment of the key 3 according to the invention enables, by combining the dimensions of the housing 1 and the contact spring 2, the shapes of the side portions 22 'and 22', and the elastic properties of the contact spring 2 used material, adapting to the different requirements of a particular application such as for example a suitable force, and the total height of the key 3. The height of the key 3 according to the invention is not limited by the choice of the PTIV 4 soldering technology since it is subsequently inserted in the openings 41 'and 41' and may be as required by the interior design of the meter.

Consequently, the button 3 of the invention has the advantage that it is not necessary to solder the key 3 to PTIV.

A further advantage of the key 3 according to the invention is a large working and oversized stroke, which ensures sufficient hysteresis of the switching and consequently reliable operation even under conditions of temperature changes, vibrations, torque due to the action of external forces on the meter housing at the time of assembly and the like.

Claims (16)

Patent claims 1. A sensor key (3) for detecting the opening of the electric meter cover positioned inside the housing of said counter, characterized in that it consists of a housing (1) and a contact spring (2) inserted in the housing (1); (14 ') and (14') of the housing (1) are provided with tongues (1G) and (11 ") which are directed towards the upper part (15) of the housing (1) and which are curved towards the inside of the housing (1) keys (3); characterized in that the key (3) is arranged in such a way that the side portions (14 ') and (14 ") are pushed into the printed circuit (4) and (41') of the printed circuit board (4), which on the opposite surfaces comprises contact surfaces (42 ' ) and (42 "), whose key is electrically closed / unlocked, the tabs (1G) and (11") being stuck to the bottom surface of the printed circuit board (4); the contact spring (2) is positioned in the stressed state with the key (3) in order to press the housing (1) upwards, thereby ensuring - the pressure of the e-tags (1G) and (11 ") on the contact surface (42") of the printed circuit board 4), - pressing the contacts of the parts (23 ') and (23') to the contact surface (42 ') of the printed circuit board (4), and - pressing the upper part (21) of the spring (2) to the lower surface of the upper part (1). 2. The sensor key (3) according to claim 1, characterized in that the contact spring (2) is curved in both side portions (22 ') and (22 ") symmetrically with respect to the vertical axis (24). 3. The sensor key (3) according to claim 2, characterized in that the curvature of the lateral parts (22 ') and (22 ") is concave, convex or combined with respect to the vertical axis (24). The sensor key (3) according to claim 2 or 3, characterized in that the side parts (22 ') and (22 ") are curved mutually asymmetrically. The sensor key (3) according to any one of the preceding claims, characterized in that the contact spring (2) is curved on both the contact portions (23 ') and (23 "). The sensor key (3) according to any one of the preceding claims, characterized in that the width (hi) of the contact spring (2) in its substantial part is smaller than the inner width (HI) of the housing (1) of the sensor key (3), and the width h2) of the spring (2) in the upper part (21) is symmetrically enlarged with the teeth (211) and (212), the width (h2) being equal to or greater than the inside width (HI) of the housing (1). The sensor key (3) according to claim 6, characterized in that the key (3) is arranged in such a way that the contact spring (2) is pushed into the housing (1) of the key (3) so that the outer surface (21) to the inner surface of the upper part (15) of the housing (1), wherein the teeth (211) and (212) are stuck to the tabs (12 ') and (12'). The sensor key (3) according to claim 7, characterized in that in the process of assembly of the key (3), the housing (1) and the spring (2) are positioned in such a way that the openings (13) and (25) are placed on the guide assembly thorns. The sensor key (3) according to claim 7, characterized in that the housing (1) of the button (3) is provided with conical surfaces (16 ') and (16 ") on the lower edge of both lateral parts (14') and (14" ). 10. The touch key (3) according to any one of the preceding claims, characterized in that the side panels (14 ') and (14') of the housing (1) of the key (3) are provided with two extensions (171 ') and (172' ) and (171 ") and (172") which limit the movement of the key (3) · The sensor key (3) according to any one of the preceding claims, characterized in that the housing (1) and the contact spring (2) of the button (3) are made of a corrosion-resistant and electrically conductive metal of high strength. The sensor key (3) according to claim 11, characterized in that the housing (1) is made of bronze or new silver. The sensor key (3) according to claim 11, characterized in that the housing (1) is made of stainless steel. A sensor key (3) according to claim 11, characterized in that the contact spring (2) of the button (3) is made of beryllium bronze. The sensor key (3) according to any one of claims 11 to 14, characterized in that the housing (1) and / or the contact spring (2) is surface-protected with a thin layer of a corrosion-inerted metal such as nickel, silver, gold or similarly. 16. The sensor key (3) according to any one of the preceding claims, characterized in that the key (3) is activated by closing the meter cover, via the lever or directly, in a manner that is pressed against the plate of the printed circuit board (4) and thereby electrically disengaged contact surface (42 ') and (42 ").