JP2007187525A - Microcomputer gas meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microcomputer gas meter which can remove a coat of paint on a case and establish electric continuity through a clamping screw by tightening the clamping screw, thereby achieving a reduction in costs. <P>SOLUTION: The microcomputer gas meter includes a gas meter case 11 which is divided into an upper case 12 having a gas inflow cap 14 and a gas outflow cap 15 which are connected to gas piping and a lower case 13 having a controller case 20 incorporating an electronic circuit component 42. The upper case 12 and the lower case 13 are electrically continued to each other by connecting them with the clamping screw 25, thereby allowing the electronic circuit component to be equipotentially connected to the gas piping through the upper case 12, the lower case 13, and the clamping screw 25. Protrusions 28 are provided on the surface of the gas meter case 11 with which a head 26 of the clamping screw 25 is brought into contact. The coat of paint 29 on the surface of the protrusions is removed by tightening the clamping screw, thereby allowing the gas meter case to be electrically continued through the clamping screw. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microcomputer gas meter provided with a bidirectional shut-off valve that shuts off gas flow in the event of abnormal use of gas, when an earthquake occurs, when gas pressure drops, or in other emergency situations.

  Built-in shut-off valve, seismic device for detecting earthquake, pressure sensor for detecting gas pressure drop and control circuit inside gas meter body, and shut-off valve in case of emergency such as abnormal use of gas, earthquake or gas pressure drop A microcomputer gas meter is known in which a bidirectional shutoff valve is operated to shut off the gas flow (see, for example, Patent Document 1).

  In this microcomputer gas meter, a controller case is provided on the front surface of the gas meter body, and a shut-off valve opening switch mechanism including a display lamp and a return switch is provided on a printed circuit board inside the controller case. In an emergency, when the bidirectional shutoff valve inside the gas meter main body is closed to shut off the gas flow port, the display lamp blinks to notify that the bidirectional shutoff valve is shut off. Further, when the return switch is turned on, the bidirectional shut-off valve can be electrically opened, and when the bidirectional shut-off valve is opened, the display lamp is turned off.

  Various electronic circuit components for controlling the pressure sensor and the bidirectional shut-off valve are mounted on the printed circuit board. When noise enters the electronic circuit components, normal reception and signal processing are hindered. Therefore, in the microcomputer gas meter, the printed circuit board is electrically connected to the gas meter body, and the gas meter body is connected to the gas pipe. In other words, the gas meter is installed by connecting it to a metal gas pipe through a base constituting the gas inlet and the gas outlet, so that the printed circuit board and the gas pipe have the same potential by installing the microcomputer gas meter. ing.

However, the gas meter case forms a measuring chamber and is divided into two parts, a lower case having a controller case and an upper case having a gas inlet and a gas outlet, and both cases are joined together through packing. It is connected by multiple clamping screws. Therefore, the lower case and the upper case are electrically insulated by the packing, but the tightening screw penetrates both cases and is in an electrically conductive state. For this reason, the printed circuit board inside the controller case is electrically connected to the lower case via a fastening screw, and the lower case is electrically connected to the upper case via a fastening screw for coupling to the upper case, The upper case has the same potential as that of the gas pipe through a base constituting the gas inlet and the gas outlet.
JP 2000-292237 A

  However, the lower case and the upper case of the gas meter case are generally painted after being formed by aluminum die casting. That is, the surfaces of the lower case and the upper case are painted before assembly. Therefore, even if the flange portion of the lower case and the upper case are joined by the fastening screw, the lower surface of the head of the fastening screw is electrically insulated by the coating film, and both cases are electrically connected via the fastening screw. It cannot be made conductive.

  Therefore, in the prior art, as shown in FIGS. 5A and 5B, when the upper case b and the lower case c are coupled by the tightening screw a, the coating film d on the flange portion of the upper case b is peeled off. The lower surface of the head e of the tightening screw a is in contact with the paint film peeling surface f of the upper case b. Also, as shown in FIGS. 6A and 6B, before painting, a masking tape h that covers the peripheral portion is applied to the fastening screw insertion hole g of the upper case b, and the masking tape h is peeled off after painting. Thus, the lower surface of the head e of the tightening screw a is in contact with the unpainted surface i of the upper case b.

  However, in the case of FIG. 5, the operation of peeling the coating film d is troublesome, the peeled state is not uniform, and conduction variation occurs. Further, in the case of FIG. 6, the number of masking work steps increases, which causes an increase in cost.

  The present invention has been made paying attention to the above circumstances, and its purpose is to peel the paint film of the case by tightening the tightening screw and to make it electrically conductive through the tightening screw. It is possible to provide a microcomputer gas meter that can reduce costs.

  In order to achieve the above-mentioned object, according to the present invention, a gas meter case includes a gas inlet case connected to a gas pipe, an upper case having a gas outlet gold, and a controller case containing an electronic circuit component. The upper case and the lower case are coupled to each other by a tightening screw to be electrically connected, and the electronic circuit component is connected to the gas pipe through the upper case, the lower case, and the tightening screw. In the microcomputer gas meter connected to the electric potential, a convex portion is provided on the surface of the gas meter case where the head of the fastening screw contacts, and the coating film on the convex portion surface is peeled off by tightening the fastening screw, and the gas meter The case is characterized in that the case is electrically connected via the tightening screw.

  A second aspect of the present invention is characterized in that a plurality of the convex portions of the first aspect are provided on the surface of the gas meter case on the surface where the head of the fastening screw contacts.

  According to a third aspect of the present invention, the gas meter case is divided into an upper case having a gas inlet gold and a gas outlet gold connected to a gas pipe and a lower case having a controller case containing an electronic circuit component. In a microcomputer gas meter in which a case is coupled to and electrically connected by a tightening screw, and the electronic circuit component is connected to the same potential as the gas pipe via the upper case, the lower case and the tightening screw, the head of the tightening screw A scratching portion is provided on a surface that contacts the gas meter case, and the coating film of the gas meter case is peeled off at the scratching portion by tightening the tightening screw to electrically connect the gas meter case via the tightening screw. It was made to do.

  According to the present invention, by tightening the tightening screw, the paint film of the case can be peeled off and brought into an electrically conductive state via the tightening screw, so that the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 3 show a first embodiment of a microcomputer gas meter, FIG. 1 is a front view of the microcomputer gas meter, and FIG. 2 is a longitudinal side view of the same. The gas meter case 11 formed by die casting or the like and having a painted surface is divided into two by an upper case 12 and a lower case 13. A gas inlet gold 14 and a gas outlet gold 15 are provided at the upper part of the upper case 12, and a distribution chamber 16 for storing a crank mechanism (not shown) and the like is provided therein. The lower case 13 is provided with a partition wall 13b. On both sides of the partition wall 13b, side plates 17 are provided so as to face each other, and a pair of front and rear measuring chambers 18 are provided.

  A counter unit 19 that digitally displays the gas flow rate is provided on the front surface of the upper case 12, and a controller case 20 formed of a synthetic resin material is provided on the front surface of the lower case 13. The controller case 20 is provided with a security display portion 21, and a push button portion 22 of a shut-off valve opening switch mechanism is provided in the vicinity of the security display portion 21.

  Next, the coupling structure between the upper case 12 and the lower case 13 will be described. As shown in FIGS. 3A and 3B, a flange portion 12 a is integrally provided at the lower end portion of the upper case 12. A flange portion 13 a is integrally provided at the upper end portion of the lower case 13. A plurality of screw insertion holes 23 are formed in the flange portion 12 a of the upper case 12, and screw holes 24 are formed in the flange portion 13 a of the lower case 13 corresponding to the screw insertion holes 23. A packing 24a is interposed between the flange portions 12a and 13a in order to airtightly connect the upper case 12 and the lower case 13. The screw insertion hole 23 is provided with a fastening screw 25 that passes through the packing 24 a and is fastened to the screw hole 24, and the upper case 12 and the lower case 13 are coupled to each other by the fastening screw 25.

Furthermore, on the upper surface of the flange portion 12a of the upper case 12, a surface 27 that contacts the lower surface of the head 26 of the tightening screw 25, that is, a plurality of protrusions projecting upward at the opening edge portion of any one screw insertion hole 23. In the present embodiment, four convex portions 28 are provided at intervals. These convex portions 28 are formed at the same time that the gas meter case 11 is manufactured by aluminum die casting or the like. After that, the surface of the gas meter case 11 is painted, so that the surface of the convex portion 28 is also provided with a coating film 29. .
However, in the assembling process for joining the upper case 12 and the lower case 13, as described above, when the tightening screw 25 is inserted into the screw insertion hole 23 and tightened into the screw hole 24, the head portion 26 of the tightening screw 25 is tightened. Since the lower surface of the surface scratches the surface of the convex portion 28, the coating film 29 of the convex portion 28 is peeled off. Accordingly, the aluminum die cast surface of the upper case 12 is in a state where it can be electrically connected to the head portion 26 of the tightening screw 25, and the upper case 12 is in a state where it can be electrically connected to the lower case 13 via the tightening screw 25. Become.

  Note that the structure for connecting the upper case 12 and the lower case 13 so as to be electrically conductive by the tightening screw 25 is not limited to the connection between the upper case 12 and the lower case 13, but the tightening for connecting the partition wall 13 b of the lower case 13 and the side plate 17. The present invention can also be applied to the screw 30 portion. That is, when the convex portion 28 is provided at the opening edge portion of the screw insertion hole 31 provided in the side plate 17 and the tightening screw 30 is inserted into the screw insertion hole 31 and tightened into the screw hole 32, the head of the tightening screw 30 is tightened. Since the lower surface of 33 scratches the surface of the convex portion 28, the coating film 29 on the convex portion 28 can be peeled off. Therefore, the background of the side plate 17 can be electrically connected to the head 33 of the fastening screw 30, and the side plate 17 can be electrically connected to the lower case 13 via the fastening screw 30.

  The controller case 20 made of synthetic resin includes a base 34 and a cover 35 fixed to the base 34, and forms a circuit component storage chamber 36 therein. A boss 37 having a screw hole 37 a is provided on the side plate 17 facing the base 34 of the controller case 20. A mounting base 39 having a fitting portion 38 that fits into the boss 37 is integrally provided on the base 34 facing the boss 37. A printed circuit board 40 is supported on the mounting base 39 of the base 34, and this printed circuit board 40 is fixed to the mounting base 39 by a fixing screw 41 screwed into the screw hole 37a.

  In this case, the head of the fixing screw 41 is joined to the conductive film portion 40 a of the printed circuit board 40, and the printed circuit board 40 is fixed to the side plate 17 through the fixing screw 41 so as to be electrically conductive. Various electronic circuit components 42 are mounted on the printed circuit board 40, and the printed circuit board 40 is connected to the gas pipe via the fixing screw 41 → the side plate 17 → the fastening screw 30 → the lower case 13 → the fastening screw 25 → the upper case 12. It will be.

  4A and 4B show a second embodiment, in which FIG. 4A is a longitudinal side view showing a tightening screw before tightening, and FIG. 4B is a longitudinal side view showing after the tightening screw is tightened. In the present embodiment, the lower surface of the head 44 of the tightening screw 43 is provided with a scratching portion 45 made of sharp nails and sharp teeth.

For example, when this tightening screw 43 is used in an assembly process for joining the upper case 12 and the lower case 13, the tightening screw 43 is inserted into the screw insertion hole 23 and tightened into the screw hole 24. Since the scratched portion 45 on the lower surface of the head 44 of the 43 scratches the coating film 29, the coating film 29 is peeled off. Accordingly, the background of the upper case 12 is in a state where it can be electrically connected to the head 44 of the tightening screw 43, and the upper case 12 is in a state where it can be electrically connected to the lower case 13 via the tightening screw 43. Therefore, the same effect as the first embodiment can be obtained.
The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be combined.

The front view of the microcomputer gas meter which shows 1st Embodiment of this invention. The longitudinal section side view of the microcomputer gas meter which shows the embodiment. The same embodiment is shown, (a) is a plan view and vertical side view showing the tightening screw before tightening, (b) is a vertical side view showing the tightening screw after tightening. The 2nd Embodiment of this invention is shown, (a) is the vertical side view which shows the fastening of a fastening screw, (b) is the longitudinal side view which shows after the fastening of a fastening screw. A prior art example is shown, (a) is a plan view and a longitudinal side view showing before tightening of the tightening screw, (b) is a longitudinal side view showing after tightening of the tightening screw. A conventional example is shown, (a) is a longitudinal side view in a masking state, (b) is a longitudinal side view in a state in which masking is peeled off.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Gas meter case, 12 ... Upper case, 13 ... Lower case, 14 ... Gas inlet gold, 15 ... Gas outlet gold, 20 ... Controller case, 25 ... Clamping screw, 26 ... Head, 28 ... Projection, 29 ... Paint film, 40 ... Printed circuit board, 42 ... Electronic circuit components

Claims (3)

A gas meter case is divided into an upper case having a gas inlet gold and a gas outlet gold connected to a gas pipe and a lower case having a controller case containing an electronic circuit component, and the upper case and the lower case are tightened with screws. In the microcomputer gas meter that is electrically coupled and electrically connected, and the electronic circuit component is connected to the same potential as the gas pipe through the upper case, the lower case, and a clamping screw,
A convex portion is provided on the surface of the gas meter case where the head of the fastening screw contacts, and the coating film on the surface of the convex portion is peeled off by tightening the fastening screw, so that the gas meter case passes through the fastening screw. A microcomputer gas meter characterized by electrical conduction. The microcomputer gas meter according to claim 1, wherein a plurality of the convex portions are provided on a surface of the gas meter case on a surface with which a head of the tightening screw contacts. A gas meter case is divided into an upper case having a gas inlet gold and a gas outlet gold connected to a gas pipe and a lower case having a controller case containing an electronic circuit component, and the upper case and the lower case are tightened with screws. In the microcomputer gas meter that is electrically coupled and electrically connected, and the electronic circuit component is connected to the same potential as the gas pipe through the upper case, the lower case, and a clamping screw,
A scratching portion is provided on a surface of the tightening screw that contacts the gas meter case, and the coating film of the gas meter case is peeled off by the scratching portion by tightening the tightening screw, and the gas meter case is inserted through the tightening screw. A microcomputer gas meter characterized by being electrically conductive.

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