Weighing device

Abstract

The present invention provides a weighing device that can improve the workability related to the removal of diaphragms. [Solution] The weighing device 1 comprises a weighing pan 2 on which an object to be weighed is placed, a weighing mechanism 4 having a projection 41c that receives the load from the weighing pan 2 and weighs the mass of the object placed on the weighing pan 2, an inner housing 5 that houses the weighing mechanism 4, and a diaphragm 11 connected to the projection 41c. The inner housing 5 has a lid 54 that closes the opening above the weighing mechanism 4. The lid 54 is provided with a through hole 54a that exposes the projection 41c. The outer edge 112 of the diaphragm 11 is fixed to the edge of the through hole 54a of the lid 54.

Description

Technical Field

[0001] The present disclosure relates to a weighing device.

Background Art

[0002] Patent Documents 1 and 2 disclose a configuration in which a diaphragm is provided to prevent intrusion of water, dust, etc. into the inside of a housing in which a weighing block (weighing mechanism) is accommodated. In the weighing device described in Patent Documents 1 and 2, an annular member for attaching the diaphragm is attached to the weighing block, and the diaphragm is attached to the annular member. Specifically, the inner edge portion (thick portion) of the diaphragm is inserted and fixed into a groove portion provided on the outer peripheral portion of the protruding portion of the weighing block, and then the outer edge portion of the diaphragm is screwed to the annular member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the attachment structure of the diaphragm as described above, for example, when performing an operation such as checking the load receiving portion (the portion covered by the diaphragm) of the weighing block, it is necessary to remove the housing cover covering the weighing block and separately remove the diaphragm from the annular member. Further, in order to appropriately attach the diaphragm to the annular member by screwing as described above, the position (orientation) of the diaphragm must be appropriately adjusted so that the screw holes provided in the outer edge portion of the diaphragm overlap with the screw holes provided in the annular member.

[0005] This disclosure aims to provide a weighing device that can improve the workability related to the removal of a diaphragm. [Means for solving the problem]

[0006] This disclosure includes the following weighing devices [1] to [5].

[0007] [1] A weighing mechanism having a weighing pan on which an object to be weighed is placed, and a load receiving part that receives the load from the weighing pan, and weighing the mass of the object to be weighed placed on the weighing pan, A housing for the aforementioned weighing mechanism, The load receiving portion is connected to a diaphragm, The housing has a lid that closes the opening above the weighing mechanism. The lid portion is provided with a through hole that exposes the load-receiving portion. A weighing device in which the outer edge of the diaphragm is fixed to the edge of the through hole in the lid.

[0008] In the weighing device described in [1] above, the outer edge of the diaphragm is fixed to the edge of the through-hole in the lid. Therefore, when performing any work on the part of the weighing mechanism including the load-receiving section, for example, only the lid needs to be removed, and there is no need to remove the diaphragm separately. Furthermore, since the diaphragm is fixed to the lid beforehand, there is no need to individually adjust the orientation of the diaphragm when connecting it to the load-receiving section. Therefore, the diaphragm can be easily installed. Accordingly, the above weighing device improves the workability related to the removal of the diaphragm.

[0009] [2] The inner edge of the diaphragm is made up of an annular thickened portion, The load-receiving portion of the weighing device [1] has an annular stepped portion for positioning the inner edge portion.

[0010] According to the configuration described in [2] above, when the lid is attached, the inner edge of the diaphragm is positioned on the stepped portion, so the diaphragm can be positioned appropriately and easily.

[0011] [3] The load receiving portion is composed of a columnar projection that protrudes upward in the weighing mechanism, The step portion has a shape in which the edge of the upper end of the protruding portion is cut out in a circumferential manner. [2] The weighing device.

[0012] According to the configuration described in [3] above, the inner surface and lower surface of the inner edge of the diaphragm can be positioned to be in close contact with the stepped portion.

[0013] [4] The weighing device according to [2] or [3], further comprising a pressing member that covers the upper surface of the inner edge of the diaphragm and presses the inner edge against the load receiving portion.

[0014] According to the configuration described in [4] above, a groove that clamps the inner edge of the diaphragm from above and below (i.e., the part in which the inner edge of the diaphragm is clamped) can be formed by the stepped portion of the load-receiving portion and the retaining member. This eliminates the need to push the inner edge of the diaphragm into the pre-formed groove when connecting the diaphragm to the load-receiving portion. In other words, the inner edge of the diaphragm can be properly positioned and fixed by a simple operation of placing the inner edge of the diaphragm on the stepped portion of the load-receiving portion and then covering and fixing the retaining member over the inner edge from above.

[0015] [5] The weighing device of [4], wherein the pressing member is a plate-shaped member having heat-shielding properties.

[0016] According to the configuration described in [5] above, by using a heat-insulating plate-shaped member as a member that presses down on the inner edge of the diaphragm from above, the diaphragm can prevent water and dust from entering the housing, and the pressing member can suppress the transfer of heat from the outside to the weighing mechanism inside the housing. This effectively suppresses malfunctions of the weighing mechanism and the occurrence of weighing errors. [Advantages of the Invention]

[0017] According to the present disclosure, a weighing device capable of improving the workability related to the removal of the diaphragm can be provided. [Brief Description of the Drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of a weighing device according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the weighing device. [Figure 3] FIG. 3 is a top view of the weighing device. [Figure 4] FIG. 4 is a perspective view showing the arrangement configuration inside the weighing device. [Figure 5] FIG. 5 is a cross-sectional view of the weighing device taken along the line V-V of FIG. 1. [Figure 6] FIG. 6 is a cross-sectional view of the weighing device taken along the line VI-VI of FIG. 1. [Figure 7] FIG. 7 is an exploded perspective view for explaining the attachment structure of the diaphragm. [Modes for Carrying Out the Invention]

[0019] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, in the drawings, there are parts that are exaggerated for easy explanation of the characteristic parts according to the embodiment. For this reason, the dimensional ratios of each part in the drawings may be different from the actual dimensional ratios. [Overall Configuration of the Weighing Device]

[0020] As shown in Figures 1 to 6, the weighing device 1 comprises a weighing pan 2, a pan support 3, a weighing mechanism 4, an inner housing 5 (housing), an outer housing 6, and an intervening member 7. Four support legs 8 are provided at the four corners of the bottom wall 61 of the outer housing 6 to support the outer housing 6. The weighing device 1 is an electronic scale configured to measure the weight of an item placed on the weighing pan 2. Note that the weighing pan 2 is not shown in Figures 2 and 3.

[0021] The weighing pan 2 has a weighing surface 2a on which the object to be weighed is placed. The weighing surface 2a extends along the horizontal direction and has, for example, a square or rectangular shape. In the following description, the direction perpendicular to the weighing surface 2a is called the Z-axis direction (vertical direction), one direction perpendicular to the Z-axis direction is called the Y-axis direction (in this embodiment, the direction along the straight line L (see Figure 4) where the fixed end 41a and the free end 41b of the weighing mechanism 4 are aligned), and the direction perpendicular to both the Z-axis direction and the Y-axis direction is called the X-axis direction. The X-axis direction and the Y-axis direction, respectively, are parallel to the horizontal direction.

[0022] The pan support portion 3 is a member (pan base) that supports the weighing pan 2 from below. As shown in Figures 2, 3, 5, and 6, the pan support portion 3 is positioned above the weighing mechanism 4, the inner housing 5, and the outer housing 6. The pan support portion 3 has a first portion 31 that occupies the central part of the pan support portion 3, four second portions 32 that protrude outward from the four corners of the first portion 31, and two third portions 33. Each of the two third portions 33 is positioned between two adjacent second portions 32 in the X-axis direction and protrudes outward from the first portion 31. The first portion 31 is fixed to the weighing mechanism 4 (the upper surface 41d of the free end 41b of the first strain-generating body 41, which will be described later) by a plurality (four, for example) of screws 21. As an example, one fixed end 31a of the first part 31 in the Y-axis direction (the lower side in Figure 3) is fixed to the free end 41b of the first strain body 41. A heat shield member 13, which will be described later, is placed between the first part 31 and the free end 41b of the first strain body 41. A through hole 31b is provided in the central part of the first part 31.

[0023] The weighing mechanism 4 is a mechanism for weighing the mass of an object placed on the weighing pan 2. As shown in Figures 4 to 6, the weighing mechanism 4 has a first strain body 41, a second strain body 42, and a weight placement section 43. Each of the first strain body 41 and the second strain body 42 has a roughly rectangular parallelepiped (rectangular block) shape. Each of the first strain body 41 and the second strain body 42 has a so-called Roberval mechanism. Each of the first strain body 41 and the second strain body 42 is an elastic body made of a metal such as aluminum alloy or stainless steel.

[0024] The first strain-generating body 41 extends along the Y-axis direction in the central part of the inner housing 5 in the X-axis direction when viewed from the Z-axis direction. The first strain-generating body 41 has a fixed end 41a and a free end 41b. The fixed end 41a is fixed to the bottom wall 51 of the inner housing 5, which will be described later, via a support member 9. In other words, the fixed end 41a is fixed to the inner housing 5. The free end 41b is positioned parallel to the fixed end 41a in the Y-axis direction. The free end 41b has a projection 41c that protrudes upward, and the upper surface 41d of the projection 41c is connected to the first part 31 via a heat shield member 13. In other words, the free end 41b is connected to the pan support part 3. The free end 41b is connected to the weighing pan 2 via the pan support part 3 and is the part to which the load from the weighing pan 2 is applied. The first strain-generating body 41 has a lever mechanism (not shown) for reducing the load from the weighing pan 2.

[0025] The weighing mechanism 4 further includes a tuning fork sensor (vibration-type load sensor, not shown) incorporated (fixed) into the first strain body 41. As an example, when an object to be weighed is placed on the weighing pan 2, a load corresponding to the weight of the object to be weighed is applied to the free end 41b of the first strain body 41, causing the first strain body 41 to deform. Then, a load corresponding to the deformation of the first strain body 41 is applied to the tuning fork sensor, and the vibration frequency of the tuning fork vibrator in the tuning fork sensor changes according to the magnitude of the load. A weight sensor (not shown) configured to measure the weight of the object to be weighed based on the vibration (vibration frequency) of the tuning fork vibrator is connected to the tuning fork sensor. The configuration of the weighing mechanism 4 is not limited to the tuning fork type described above, and other configurations such as a strain gauge type may be used.

[0026] The second strain body 42 is fixed to the first strain body 41. For example, the second strain body 42 is smaller than the first strain body 41. The weight placement section 43 is fixed to the second strain body 42. The weight W is placed on the weight placement section 43 by a weight moving mechanism (not shown) configured to grip and move the weight W. When the weight W is placed on the weight placement section 43, the second strain body 42 deforms. Then, a load corresponding to the deformation of the second strain body 42 is applied to the tuning fork sensor. This allows the weighing mechanism 4 (tuning fork sensor) to be calibrated. Note that when weighing an object, the weight W is not placed on the weight placement section 43, but is held, for example, by the weight moving mechanism.

[0027] The inner housing 5 is a component that houses the weighing mechanism 4. As shown in Figures 2 to 6, the inner housing 5 is located below the pan holder 3. The inner housing 5 has a bottom wall 51, side walls 52, a top wall 53, and a lid 54. The bottom wall 51, side walls 52, and lid 54 define the housing space V in which the weighing mechanism 4 is housed. The bottom wall 51 is located below the weighing mechanism 4. The fixed end 41a of the first strain-generating body 41 is fixed to the bottom wall 51 via a support member 9. The side wall 52 is positioned to cover the sides of the weighing mechanism 4. The side wall 52 is formed in a rectangular cylindrical shape that extends upward, connected to the edge of the bottom wall 51, so as to surround the weighing mechanism 4 (housing space V) when viewed from the Z-axis direction.

[0028] The top wall 53 is connected to the upper end 52a of the side wall 52 (the end opposite to the end of the side wall 52 that is connected to the bottom wall 51). The top wall 53 extends horizontally so as to project outward from the upper end 52a and is formed in a substantially rectangular ring shape when viewed from the Z-axis direction. The lid 54 is fixed to the upper end 52a of the side wall 52 by a plurality of screws S1 (see Figure 7), for example, eight screws, so as to close the opening defined by the upper end 52a of the side wall 52 (close the storage space V). The lid 54 is located below the countersunk portion 3 and extends horizontally. The lid 54 is provided with a through hole 54a for the projection 41c of the first strain-generating body 41 to pass through. In other words, the free end 41b is connected to the countersunk portion 3 located above the lid 54 by passing through the lid 54 via the through hole 54a.

[0029] The inner housing 5 has an upper surface 5a facing the dish support portion 3. For example, the upper surface 5a is composed of the upper surface of the side wall 52, the upper surface of the top wall 53, and the upper surface of the lid portion 54. The upper surface 5a is formed in a substantially rectangular shape when viewed from the Z-axis direction. The inner housing 5 has four corners 55 when viewed from the Z-axis direction. For example, the four corners 55 are the parts that correspond to the four corners of the upper surface 5a when viewed from the Z-axis direction (parts included in the vicinity of the four corners). The inner housing 5 has four edges 56 when viewed from the Z-axis direction. Each of the four edges 56 is the part that connects two adjacent corners 55 and is the part that corresponds to the four sides of the upper surface 5a when viewed from the Z-axis direction (parts included in the vicinity of the four sides).

[0030] The outer housing 6 is a component that houses the inner housing 5. As shown in Figures 1 to 6, the outer housing 6 is positioned below the pan head 3. The outer housing 6 has a bottom wall 61 and side walls 62. The bottom wall 61 is positioned below the bottom wall 51 of the inner housing 5. The bottom wall 61 is fixed to the bottom wall 51, for example, by screws (not shown). The side walls 62 are positioned to cover the sides of the side walls 52 of the inner housing 5. The side walls 62 are formed in a rectangular tubular shape that extends upward and is connected to the edge of the bottom wall 61, so as to surround the side walls 52 when viewed from the Z-axis direction.

[0031] The intervening member 7 is a member positioned between the inner housing 5 and the outer housing 6, and is, for example, an elastic member. As shown in Figure 2, the intervening member 7 is formed in a substantially rectangular annular shape. The intervening member 7 is positioned between the top wall 53 of the inner housing 5 and the side wall 62 of the outer housing 6. In other words, the top wall 53 of the inner housing 5 and the side wall 62 of the outer housing 6 are connected to each other via the intervening member 7. Note that the intervening member 7 is not shown in Figures 5 and 6.

[0032] As shown in Figures 3 to 6, the weighing device 1 further includes a porous membrane 10, a diaphragm 11, a retaining plate 12, and a heat shielding member 13 as a waterproof structure.

[0033] The porous membrane 10 is, for example, 1 cm 2 The porous membrane is made of tetrafluoroethylene resin having hundreds of millions of micropores per unit area. The porous membrane 10 is waterproof, dustproof, and breathable. The porous membrane 10 is attached to the bottom wall 51 of the inner housing 5 so as to block the through-holes 51a provided in the bottom wall 51. For example, the through-holes 51a are provided in a stepped portion 57 of the bottom wall 51. The stepped portion 57 is a portion where the inner surface of the bottom wall 51 is recessed toward the housing space V compared to the portion of the bottom wall 51 other than the stepped portion 57.

[0034] The diaphragm 11 is an annular member formed of, for example, silicone rubber. The diaphragm 11 is composed of an inner edge portion 111 and an outer edge portion 112, which are thick annular bodies, and an annular thin-walled portion 113 that connects the inner edge portion 111 and the outer edge portion 112. The thin-walled portion 113 is formed in a corrugated shape that undulates concentrically. The inner edge portion 111 and the outer edge portion 112 are thicker than the thin-walled portion 113. The outer edge portion 112 of the diaphragm 11 is positioned on the lid portion 54 so as to follow the edge of the through hole 54a of the lid portion 54. The retaining plate 12 is positioned on the outer edge portion 112 of the diaphragm 11 and is fixed to the lid portion 54 by screws 22 (see Figures 3 and 7). This prevents water and dust from entering the inside of the inner housing 5 through the through hole 54a.

[0035] The heat shield member 13, as described later, plays the role of pressing and fixing the inner edge 111 of the diaphragm 11 against the protrusion 41c, and also prevents heat transfer from the outside of the inner housing 5 to the metering mechanism 4. The heat shield member 13 is a disc-shaped member made of, for example, stainless steel. The heat shield member 13 is positioned on the upper surface 41d of the protrusion 41c and is fixed to the free end 41b by a screw 23. [Details of the diaphragm mounting structure and its effects]

[0036] The details of the mounting structure of the diaphragm 11 will be described with reference to Figures 5 and 7. The weighing mechanism 4 has a projection 41c as a load-receiving portion that receives the load from the weighing pan 2. In this embodiment, the projection 41c is configured to receive the load from the weighing pan 2 via the pan-receiving portion 3. The diaphragm 11 is connected to the projection 41c. In this embodiment, the inner edge 111 of the diaphragm 11 is in contact with the projection 41c (in this embodiment, the stepped portion 41e, which will be described later) so as not to create a gap. The inner housing 5 has a cover portion 54 that closes the opening above the weighing mechanism 4 (in this embodiment, the opening defined by the upper end portion 52a of the side wall 52).

[0037] The cover portion 54 is provided with a through hole 54a that exposes the protruding portion 41c. The outer edge portion 112 of the diaphragm 11 is fixed to the edge of the through hole 54a of the cover portion 54. More specifically, the outer edge portion 112 of the diaphragm 11 is positioned to overlap the upper surface 5a side of the edge of the through hole 54a. Multiple screw holes 54b (for example, six screw holes arranged at equal intervals along the edge of the through hole 54a) are provided on the edge of the through hole 54a in the cover portion 54. Multiple (for example, six) screw holes 112a are provided on the outer edge portion 112 of the diaphragm 11 that overlap with the multiple screw holes 54b. The retaining plate 12 is formed in an annular shape that is approximately the same size as the outer edge portion 112. Multiple (for example, six) screw holes 12a are provided on the retaining plate 12 that overlap with the multiple screw holes 54b and 112a. With the diaphragm 11 and the retaining plate 12 positioned such that the multiple screw holes 112a in the diaphragm 11 and the multiple screw holes 12a in the retaining plate 12 overlap with the multiple screw holes 54b in the lid 54, each of the multiple screws 22 is inserted through and fixed into the screw holes 112a, 12a, and 54b from the upper surface of the retaining plate 12. In this way, the diaphragm 11 is fixed to the edge of the through hole 54a in the lid 54.

[0038] As described above, in the weighing device 1, the outer edge 112 of the diaphragm 11 is fixed to the edge of the through hole 54a of the lid 54. Therefore, for example, when performing any work on the part of the weighing mechanism 4 including the load receiving part (protrusion 41c), it is only necessary to remove the lid 54, and there is no need to perform a separate operation to remove the diaphragm 11. Also, since the diaphragm 11 is fixed to the lid 54 in advance, there is no need to individually adjust the orientation of the diaphragm 11 when connecting the diaphragm 11 to the protrusion 41c. Therefore, the diaphragm 11 can be easily installed. Accordingly, the weighing device 1 can improve the workability related to the removal of the diaphragm 11.

[0039] As shown in Figures 5 and 7, the inner edge 111 of the diaphragm 11 is made up of an annular thickened portion, and the projection 41c that receives the load from the weighing pan 2 (pan holder portion 3) in the weighing mechanism 4 has an annular stepped portion 41e for positioning the inner edge 111 of the diaphragm 11. In this embodiment, as an example, the projection 41c is formed in a columnar shape (cylindrical in this embodiment) that protrudes upward in the weighing mechanism 4, and the stepped portion 41e has a shape in which the edge of the upper end of the projection 41c is cut out in a circumferential manner (circumferential in this embodiment) so that the upper end of the projection 41c tapers discontinuously (in a step-like manner). As an example, the stepped portion 41e is composed of an annular bottom surface 41e1 (an annular surface located below the top surface 41d) parallel to the top surface 41d, and a cylindrical side surface 41e2 extending vertically from the inner end of the bottom surface 41e1 and connecting the bottom surface 41e1 and the top surface 41d. With the above configuration, when the lid portion 54 is attached to the upper end portion 52a of the side wall 52, the inner edge portion 111 of the diaphragm 11 is positioned on the stepped portion 41e, so that the diaphragm 11 can be positioned appropriately and easily. In this embodiment, by configuring the stepped portion 41e as described above, the inner surface and bottom surface of the inner edge portion 111 of the diaphragm 11 can be positioned in close contact with the stepped portion 41e. In other words, the lower surface of the inner edge portion 111 is placed on the bottom surface 41e1 of the stepped portion 41e, and the inner surface of the inner edge portion 111 comes into contact with the side surface 41e2 of the stepped portion 41e, thereby positioning the inner edge portion 111 while keeping it in close contact with the protruding portion 41c.

[0040] As shown in Figures 5 and 7, the weighing device 1 has a heat shield member 13 that covers the upper surface of the inner edge 111 of the diaphragm 11 and presses the inner edge 111 against the protrusion 41c (in this embodiment, the bottom surface 41e1 of the stepped portion 41e). With the above configuration, a groove that sandwiches the inner edge 111 of the diaphragm 11 from above and below (i.e., the portion in which the inner edge 111 of the diaphragm 11 is sandwiched) can be formed by the stepped portion 41e and the heat shield member 13. This eliminates the need to push the inner edge 111 of the diaphragm 11 into the pre-formed groove when connecting the diaphragm 11 to the protrusion 41c. In other words, the inner edge 111 of the diaphragm 11 can be properly positioned and fixed by a simple operation of placing the inner edge 111 of the diaphragm 11 on the stepped portion 41e of the protruding portion 41c and then covering and fixing the heat shielding member 13 over the inner edge 111 from above.

[0041] Furthermore, as described above, by using a heat-shielding plate-shaped member (heat-shielding member 13) as a member that presses down on the inner edge 111 of the diaphragm 11 from above, in addition to preventing water and dust from entering the inner housing 5 with the diaphragm 11, the transfer of heat from the outside to the weighing mechanism 4 inside the inner housing 5 can be suppressed by the heat-shielding member 13. This effectively suppresses malfunctions of the weighing mechanism 4 and the occurrence of weighing errors. [Differentiation]

[0042] This disclosure is not limited to the embodiments described above. The materials and shapes of each of the above-described components are not limited to those described above, and various materials and shapes can be used. Furthermore, some of the components included in the above embodiments may be omitted or modified as appropriate. For example, although some characteristic components included in the above embodiments and some effects exhibited by each component have been described, the weighing device according to this disclosure does not necessarily have to be configured to exhibit all of the effects described in the above embodiments, and may be configured to exhibit only some of the effects described in the above embodiments. In the latter case, the weighing device only needs to have components that are essential to exhibit at least those components, and components that are not essential to exhibit those components may be omitted or modified as appropriate.

[0043] For example, in the above embodiment, a heat-shielding member 13 was used as a pressing member to press the inner edge 111 of the diaphragm 11 against the protrusion 41c, but the pressing member may be a member that does not have heat-shielding properties. Alternatively, a part of the pan holder 3 may also serve as the pressing member. In this case, the pressing member (heat-shielding member 13), which is a separate member from the pan holder 3, may be omitted. Also, in the above embodiment, the outer edge 112 of the diaphragm 11 was screwed to the edge of the through hole 54a, but the outer edge 112 of the diaphragm 11 may be fixed to the lid 54 by a fixing method other than screwing. Furthermore, the diaphragm 11 is not limited to an annular shape as in the above embodiment, but may be formed in an annular shape other than an annular shape (for example, a polygonal annular shape). Similarly, the protrusion 72 may be shaped according to the shape of the diaphragm 11. For example, if the diaphragm 11 is a polygonal annular shape, the protrusion 72 may be formed in a polygonal columnar shape corresponding to the polygonal annular shape. [Explanation of symbols]

[0044] 1...Weighing device, 2...Weighing pan, 4...Weighing mechanism, 5...Inner housing (housing), 11...Diaphragm, 41c...Protrusion (load receiving part), 41e...Stepped part, 54...Lid part, 111...Inner edge part, 112...Outer edge part.

Claims

1. A weighing mechanism having a weighing pan on which an object to be weighed is placed, and a load receiving part that receives the load from the weighing pan, and weighing the mass of the object to be weighed placed on the weighing pan, A housing for the aforementioned weighing mechanism, The load receiving portion is connected to a diaphragm, The housing has a lid that closes the opening above the weighing mechanism. The lid portion is provided with a through hole that exposes the load-receiving portion. A weighing device in which the outer edge of the diaphragm is fixed to the edge of the through hole in the lid.

2. The inner edge of the diaphragm is composed of an annular thickened portion. The weighing device according to claim 1, wherein the load-receiving portion has an annular stepped portion for arranging the inner edge portion.

3. The load-receiving portion is composed of a columnar projection that protrudes upward in the weighing mechanism. The weighing device according to claim 2, wherein the stepped portion has a shape in which the edge of the upper end of the protruding portion is cut out in a circumferential manner.

4. The weighing device according to claim 2 or 3, further comprising a pressing member that covers the upper surface of the inner edge of the diaphragm and presses the inner edge against the load-receiving portion.

5. The weighing device according to claim 4, wherein the pressing member is a plate-shaped member having heat-shielding properties.

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