Weight measuring device and load cell unit

Abstract

The weight measuring device comprises: a housing cover that bears the load of a measured object; a plurality of force measuring elements that support the housing cover and detect the load; a housing base that has a concave-convex portion for each of the plurality of force measuring elements, the concave-convex portion having an upwardly opening recess that accommodates at least a portion of the force measuring element and fixes the force measuring element, and a convex portion that protrudes downward corresponding to the recess; and an adjusting leg that accommodates at least a portion of the concave-convex portion and has an adjusting mechanism portion for adjusting the height position at a position opposite to the side of the concave-convex portion.

Description

Technical Field

[0001] The invention relates to a weight measuring device with an adjustable leg and a force-measuring cell unit. Background Art

[0002] If the weight measuring device is set on an inclined surface to measure the load, the load does not act vertically on the weight measuring device, so the correct output for the load cannot be obtained. In order to solve this problem, a weight measuring device having an adjustment leg having a function (leveling function) for setting the weight measuring device horizontal has been known. If the types of structural forms of the weight measuring device having the adjustment leg are roughly divided, there are devices of the type of structural form in which the adjustment leg is provided directly below the force measuring element (for example, refer to patent document 1) and devices of the type of structural form in which the adjustment leg is provided at a position away from the force measuring element (for example, refer to patent document 2).

[0003] Patent Document 1: Japanese Utility Model Application Laid-Open No. 07-014329

[0004] Patent Document 2: Japanese Patent Application Publication No. 2013-011489

[0005] However, in the device shown in the above-mentioned patent document 1, the mounting position of the adjustment leg is set just below the force measuring element in order to ensure the specified performance of the device, resulting in a thicker overall thickness of the device. In addition, in the device shown in the patent document 2, the adjustment leg is located at a position away from the force measuring element, so the device has a rigid structure in order to ensure the specified performance of the device, resulting in a thicker overall thickness of the device. Summary of the invention

[0006] The present invention solves the above-mentioned problems, and an object of the present invention is to provide a weight measuring device and a load cell unit having an adjustment leg that can achieve a thinner overall thickness while ensuring a predetermined performance.

[0007] In order to achieve the above-mentioned problems, the first mode of the weight measuring device of the present invention is characterized in that it comprises: a housing cover, which bears the load of the measured object; a plurality of force measuring elements, which support the housing cover and detect the load; a housing base, which has a concave-convex portion for each of the plurality of force measuring elements, the concave-convex portion having a concave portion opening upward for accommodating at least a portion of the force measuring element and fixing the force measuring element, and a convex portion protruding downward corresponding to the concave portion; and an adjustment leg, which accommodates at least a portion of the concave-convex portion and has an adjustment mechanism portion for adjusting the height position at a position opposite to the side of the concave-convex portion.

[0008] In addition, the force measuring element unit of the second embodiment of the present invention is characterized in that it comprises: a housing cover that bears the load of the object to be measured; a force measuring element that supports the housing cover and detects the load; a housing base that has a concave-convex portion, the concave-convex portion having a concave portion opening upward for accommodating at least a portion of the force measuring element and fixing the force measuring element, and a convex portion protruding downward corresponding to the concave portion; and an adjustment leg that accommodates at least a portion of the concave-convex portion and has an adjustment mechanism portion for adjusting the height position at a position opposite to the side of the concave-convex portion.

[0009] In addition, the weight measuring device of the third embodiment of the present invention is characterized in that it comprises: a plurality of force measuring cell units arranged in a planar shape; and a common cover, which integrates the shell covers of the plurality of force measuring cell units with each other, and the plurality of force measuring cell units respectively comprise: a shell cover; a force measuring cell, which supports the shell cover and detects the load of the measured object; a shell base, which has a concave-convex portion, the concave-convex portion having a concave portion opening upward for accommodating at least a portion of the force measuring cell and fixing the force measuring cell, and a convex portion protruding downward corresponding to the concave portion; and an adjustment leg, which accommodates at least a portion of the concave-convex portion and has an adjustment mechanism portion for adjusting the height position at a position opposite to the side of the concave-convex portion.

[0010] According to the first embodiment of the weight measuring device and the third embodiment of the weight measuring device of the present invention, a force measuring element is fixedly accommodated in a recessed portion of the concave-convex portion that opens upward, and an adjusting leg having an adjusting mechanism for adjusting the height position is provided at a position opposite to the side of a convex portion that protrudes downward corresponding to the concave portion in which the force measuring element is fixedly accommodated, thereby reducing the increase in the total thickness of the device caused by the adjusting leg, thereby ensuring the specified performance and achieving lightness and thinness. In addition, according to the second embodiment of the force measuring element unit of the present invention, an adjusting leg having an adjusting mechanism for adjusting the height position is provided at a position opposite to the side of a convex portion of the concave-convex portion in which the force measuring element is fixedly accommodated, thereby reducing the increase in the total thickness of the force measuring element unit caused by the adjusting leg, thereby ensuring the specified performance and achieving lightness and thinness. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a partially exploded perspective view of the weight measuring device according to the first embodiment of the present invention.

[0012] Figure 2 This is an exploded perspective view of the weight measuring device as viewed from the back.

[0013] Figure 3 (a) is a side view of the weight measuring device, Figure 3 (b) is a bottom view of the weight measuring device.

[0014] Figure 4It is an exploded perspective view of the force measuring element of the weight measuring device.

[0015] Figure 5 It is a perspective view showing a load cell attached to the weight measuring device.

[0016] Figure 6 It is a cross-sectional view explaining the side portion of the concavo-convex shape portion of the weight measuring device.

[0017] Figure 7 This is a cross-sectional view schematically illustrating the adjustment legs and operation of the weight measuring device.

[0018] Figure 8 It is a cross-sectional view of the part including the adjustment leg and the force measuring element of the weight measuring device.

[0019] Fig. 9 Yes Figure 8 A cross-sectional view of the adjustment leg in an extended state.

[0020] Fig.10 Yes means Figure 8 Side view of the exterior.

[0021] Fig.11 It is a partially broken away perspective view showing a modified example of the adjustment leg portion of the weight measuring device.

[0022] Fig.12 It is an exploded perspective view showing another modified example of the adjustment leg portion of the weight measuring device.

[0023] Fig.13 (a) is a cross-sectional view of a portion including an adjustment leg and a load cell of a weight measuring device according to a second embodiment, Fig.13 (b) is Fig.13 (a) is a cross-sectional view of the state in which the adjustment leg is extended.

[0024] Fig.14 It is a cross-sectional perspective view of a load cell unit according to a third embodiment.

[0025] Fig.15 This is a perspective view of a state where the force measuring cell is observed with the trim cover and the housing cover removed from the force measuring cell unit.

[0026] Fig.16 is Fig.15 A perspective view of the force measuring cell unit with the housing cover installed.

[0027] Fig.17 It is a perspective view showing the appearance of the load cell unit.

[0028] Fig.18It is an exploded perspective view of the force measuring cell unit.

[0029] Fig.19 This is a perspective view of a weight measuring device constructed using the load cell unit. DETAILED DESCRIPTION

[0030] Hereinafter, the weight measuring device with adjustable legs and the force measuring cell unit according to the embodiment of the present invention will be described with reference to the accompanying drawings. In this specification, in order to explain the spatial arrangement of the various parts of the weight measuring device and the force measuring cell unit, the xyz (or x'y'z) rectangular coordinate system shown in the drawings will be referred to. Here, the positive direction of the z-axis is upward in the use state of the weight measuring device and the force measuring cell unit, and the opposite direction is downward, which are marked as up and down on the z-axis, respectively.

[0031] (First embodiment)

[0032] Figures 1 to 10 1 shows a weight measuring device 1 according to a first embodiment. The weight measuring device 1 is used, for example, as a square, flat, thin, lightweight, and portable weight scale for leveling. Figure 1 , Figure 2 , Figure 3 As shown in (a) and (b) of the drawings, the weight measuring device 1 includes: a housing cover 2; a plurality of (four in this embodiment) load cells 3 that support the housing cover 2 and detect the load of the object to be measured; a housing base 4 that fixes and holds the load cells 3; and adjustment legs 5 for leveling. In addition, the weight measuring device 1 includes a decorative cover 20 on the housing cover 2.

[0033] The housing cover 2 is a member that bears a load and transmits the load to the force measuring element 3, and is fixed to the force measuring element 3 by screws 11. The housing cover 2 is a member that is supported and fixed only by the force measuring element 3. The housing cover 2 has a rigid structure, for example, formed by a steel plate, and the rigid structure has sufficient strength to bear the load and suppress deformation. In addition, the housing cover 2 can also have sufficient mechanical strength and be formed by a resin such as CFRP resin.

[0034] The decorative cover 20 is a member supported only by the housing cover 2 and fixed only to the housing cover 2. The decorative cover 20 is, for example, a member on which the feet of a person being measured are placed to contact the feet. In addition, the decorative cover 20 covers the uneven surface shape of the housing cover 2 to form a flat surface, has an aesthetic function, and has an easy-to-clean surface so that the contact surface with the feet of the person being measured can be kept clean. The decorative cover 20 is formed by molding a resin such as ABS resin, for example.

[0035] The housing base 4 is a member having a substantially square flat shape when viewed from the z-axis direction in the figure, and is subjected to the load applied to the housing cover 2 only through the force measuring element 3. The housing base 4 has a plurality of (four in the present embodiment) concave-convex portions 40 protruding downward at each corner of the quadrilateral. Each concave-convex portion 40 has: a concave portion 42 opening upward and a convex portion 41 protruding downward corresponding to the concave portion 42. The surface of the concave portion 42 and the surface of the convex portion 41 are in a front-back relationship with each other. In addition, the positions of the concave-convex portions 40 (convex portion 41 and concave portion 42) at the four corners correspond to the positions A, B, C, and D in the figure.

[0036] The force measuring elements 3 are respectively arranged so that at least a part of them is housed in the recessed portion 42 of the concavo-convex shape portion 40 and is opened upward, and are respectively fixed to the housing base 4 by two screws 12. The four force measuring elements 3 at the positions A, B, C, and D are essentially components of the same structure, and are arranged so that they rotate in the same rotation direction every 90 degrees in an adjacent order about the rotation axis in the z-axis direction. The output signal from the force measuring element 3 is processed by the circuit board 6 arranged and fixed to the central recessed portion 4a of the housing base 4. The details of the force measuring element 3 will be described later (refer to Figures 4 to 9 ).

[0037] The adjustment leg 5 has: an external thread portion 51, which is in a state where a thread groove is provided along the outer periphery of the convex portion 41 when assembled to the concave-convex portion 40 of the housing base 4; and an internal thread portion 52, which moves up and down by screwing with the external thread portion 51. The external thread portion 51 and the internal thread portion 52 constitute an adjustment mechanism portion 50 used for adjusting the height position (leveling). In the present embodiment, the external thread portion 51 is configured as a component independent of the convex portion 41 provided on the housing base 4. The internal thread portion 52 is a cylindrical member with a bottom having a shape of a threaded cover and a thread groove on the inside. Each set of the external thread portion 51 and the internal thread portion 52 arranged at each position A, B, C, and D is essentially a component of the same structure. The external thread portion 51 and the internal thread portion 52 are formed by, for example, molding a resin such as ABS resin, but are not limited thereto, as long as the required mechanical strength is satisfied.

[0038] The external threaded portion 51 includes a cylindrical portion 51a externally inserted into the convex portion 41 and three engaging protrusions 51b protruding from the upper end of the cylindrical portion 51a. The cylindrical portion 51a has a thread groove on its outer surface. The external threaded portion 51 is externally inserted and fixed to the convex portion 41, so that the thread groove becomes a thread groove along the outer periphery of the convex portion 41. The engaging protrusion 51b includes a flexible engaging piece and an engaging claw formed to protrude outward at the upper end of the engaging piece. Each engaging protrusion 51b protrudes from the cylindrical portion 51a at an angle interval of 90 degrees or 180 degrees.

[0039] In order to hold and fix the external threaded portion 51, the housing base 4 has an engaging portion 41a that engages with the engaging protrusion 51b at the portion of the concavo-convex portion 40 that reaches the base from the outer wall of the convex portion 41. The engaging portion 41a is a slit-shaped hole for the engaging protrusion 51b to be inserted from the lower surface to the upper surface of the housing base 4. For the external threaded portion 51, the engaging protrusion 51b is inserted into the engaging portion 41a by being externally inserted into the convex portion 41, and the engaging claw of the engaging protrusion 51b is engaged with the opening edge 41b of the upper surface of the hole of the engaging portion 41a and fixed to the housing base 4. For the external threaded portion 51, the engaging protrusion 51b is inserted and engaged with the engaging portion 41a, so that it will not fall off or rotate when the height of the adjustment leg 5 is adjusted. The engaging portion 41 a is formed at three locations near the corners of the positions A, B, C, and D, corresponding to the three engaging protrusions 51 b of the external thread portion 51 .

[0040] Next, the force measuring element 3 will be described in detail. Figure 4 As shown, the force measuring element 3 has a plate-shaped force measuring element body, which forms a prismatic deformation generating part 30 arranged horizontally when in use, and a fixed part 31 and a movable part 32 that respectively support the two ends (fixed end and movable end) of the deformation generating part 30 as an integrated body. The force measuring element body is arranged to be parallel to the x'y' plane orthogonal to the z-axis. It is a component that is based on the premise that the deformation generating part 30 is deformed and the fixed part 31 and the movable part 32 are not deformed. The deformation generating part 30 is a part with a certain cross-sectional area, and the place where the cross-sectional area changes to a larger one becomes the boundary with the fixed part 31 and the movable part 32. In this Figure 4 In FIG. 4 , the strain generating portion 30 is arranged such that its long side direction is oriented in the front-rear direction (y′ axis) orthogonal to the up-down direction (z axis), and the x′ axis is oriented in the left-right direction.

[0041] The fixed part 31 has an arm that bends backward after extending symmetrically from the fixed end of the deformation generating part 30, and has a fixing hole 31a near the end of the arm. The movable part 32 also has an arm that bends forward after extending symmetrically from the movable end and a fixing screw hole 32a. In addition, each arm extends to the side position of the deformation generating part 30 so that the center of the two fixing holes 31a of the fixed part 31 and the center of the two fixing screw holes 32a of the movable part 32 are included in the plane (zx' plane) that is orthogonal to the long side direction of the deformation generating part 30 and divides the length of the deformation generating part 30 into two. In other words, the two fixing holes 31a, 31a and the two fixing screw holes 32a, 32a, a total of four holes, are arranged in a straight line at symmetrical positions with respect to the deformation generating part 30. In addition, the structure of the plate-shaped force measuring element body is an example of one embodiment and is not limited to the structure shown here.

[0042] The deformation generating part 30 has a resistance type strain gauge 30a fixed closely to its upper surface. The deformation generating part 30 is deformed by the movable end receiving the load moving relative to the fixed end, and the strain gauge 30a converts the deformation into a change in resistance value. The fixed part 31 has a flexible substrate 30b on its surface. The strain gauge 30a and the flexible substrate 30b are electrically connected, for example, by a wire.

[0043] The flexible substrate 30b has a Wheatstone bridge circuit, a sensitivity adjustment resistor, a temperature compensation resistor, etc. formed by connecting to the strain gauge 30a, detects the change in resistance value of the strain gauge 30a, and outputs a detection signal obtained according to the load. The output from the flexible substrate 30b is connected to the circuit substrate 6 (see Figure 1 ) is connected. The wiring is accommodated in a wiring arrangement groove 42b formed from the recess 42 of the housing base 4 to the central recess 4a of the housing base 4 to which the circuit substrate 6 is fixed. The wiring arrangement groove 42b constitutes a retreat space for preventing the wiring from contacting the housing cover 2 arranged above, and also has a function as a structure that increases the rigidity of the housing base 4.

[0044] The force sensor body is fixed to the bottom of the recessed portion 42 by passing the screw 12 through the fixing hole 31a of the fixing portion 31 and screwing it into the threaded hole 42a of the recessed portion 42 of the housing base 4. At this time, the spacer 35 is used so that the movable portion 32 does not contact the bottom surface of the recessed portion 42, and the threaded hole 42a is formed in a seat 42c provided on the bottom surface of the recessed portion 42.

[0045] The movable part 32 is provided with a load transmission member 33 as a member for connecting with the housing cover 2 located above. The load transmission member 33 is composed of a metal disc that functions as a spacer and a support member and a truncated cone body with a trapezoidal cross section and soft elasticity arranged on the metal disc. The load transmission member 33 has two fixing holes 33a corresponding to the fixing threaded holes 32a of the movable part 32, and also has a screw 11 (see FIG. 1 ) at the upper center. Figure 1 , Figure 8 The load transmission member 33 is fixed to the movable part 32 by passing the screw 13 through the fixing hole 33a and screwing it into the fixing screw hole 32a of the movable part 32. At this time, the spacer 34 is inserted between the load transmission member 33 and the fixing hole 32a.

[0046] The spacer 34 is used to prevent the load transmission member 33 from contacting the deformation generating part 30 and the like. The metal disk of the load transmission member 33 has the periphery of the fixing hole 33a protruding downward, and functions as a spacer together with the spacer 34. The center of the load transmission member 33 is arranged just above the center of the deformation generating part 30. The load transmission member 33 transmits the load from the housing cover 2 through the front end portion of the truncated cone body whose cross section becomes narrower toward the top and has soft elasticity.

[0047] Figure 5 The load cell 3 is shown arranged and fixed in the recessed portion 42 of the housing base 4. The arrow 30c in the figure indicates the wiring from the flexible substrate 30b passing through the groove 42b provided in the housing base 4 and heading toward the circuit board 6.

[0048] Next, the structure of the adjustment leg 5 of the weight measuring device 1, the storage and installation of the force measuring cell 3, and the leveling function of setting the device horizontally by the adjustment leg 5 are described. First, the basic concept related to the configuration of the adjustment leg 5 is described. Figure 6 As shown, the concavo-convex part 40 of the weight measuring device 1 has a side space 40b extending outward from the side 40a which is the outer surface of the side wall thereof. The side space 40b exists as a free space surrounding the convex part 41 of the concavo-convex part 40.

[0049] like Figure 7 As shown, the adjustment leg 5 is arranged in the free space, i.e., the side space 40b, in a manner of surrounding the concavo-convex portion 40. Therefore, the adjustment leg 5 is arranged in a manner of accommodating at least a part of the concavo-convex portion 40 and having an adjustment mechanism 50 at a position opposite to the side 40a of the concavo-convex portion 40. The adjustment mechanism 50 adjusts the height position in a state of contact or separation relative to the side 40a. The adjustment mechanism 50 of this embodiment is composed of a pair of threaded portions of an external threaded portion 51 and an internal threaded portion 52 that are screw-fitted with each other and move up and down relatively ( Figure 1 ).

[0050] The adjustment mechanism 50 composed of the pair of threaded portions can be continuously adjusted in height by continuously rotating the internal threaded portion 52 arbitrarily.

[0051] like Figure 8 , Fig. 9 As shown, the force measuring element 3 is stored and mounted in the recessed portion 42 of the bottomed cylindrical concave-convex portion 40 formed in the housing base 4. The recessed portion 42 has a bottom surface and a rising surface formed by the inner surface of the side wall. The force measuring element 3 is fixed to the bottom surface of the recessed portion 42 in a state where it is surrounded and protected by the rising surface of the recessed portion 42.

[0052] In the present embodiment, the force measuring element 3 is housed and fixed in the recess 42 in a state where the upper portion of the load transfer member 33 thereof protrudes beyond the upper surface of the opening of the recess 42. The force measuring element 3 may be housed in the recess 42 in this manner at least in part, or the force measuring element 3 may be housed in the recess 42 as a whole. The housing base 4 is formed by CFRP or a steel plate, etc. When viewed from the outside, the recess 42 having a rising surface inside protrudes downward to form a convex portion 41. The convex portion 41 is in a tapered shape in which the outer diameter decreases from the upper portion toward the lower portion. The external thread portion 51 is externally inserted into the convex portion 41 using the outer shape of the convex portion 41 as a guide surface. Therefore, the external thread portion 51 is disposed in the side space 40b, and the side space 40b exists at a position adjacent to the side portion 40a (refer to Figure 7 ))Relative position.

[0053] The cylindrical portion 51a of the external thread portion 51 is engaged with the convex portion 41 to support the load applied to the convex portion 41 (the cylindrical portion 51a is supported from below by the internal thread portion 52). The cylindrical portion 51a may also have an inner surface shape that is a tapered shape that matches the outer surface shape of the convex portion 41 to support part or all of the load using the inner surface. Alternatively, the upper end surface of the cylindrical portion 51a may be used to support part or all of the load applied to the housing base 4. The engaging protrusion 51b of the external thread portion 51 is inserted into the through hole formed in the housing base 4, i.e., the engaging portion 41a, and engages with the opening edge portion 41b, which helps prevent the external thread portion 51 from falling off and rotating. The internal thread portion 52 is screwed together (rotational thread connection) with respect to the external thread portion 51 assembled on the housing base 4 so that the thread grooves and thread teeth of each other are matched. The external thread portion 51 may be assembled to the housing base 4 in a state of being screwed together with the internal thread portion 52 to form an integrated whole, or only the external thread portion 51 may be assembled to the housing base 4 and then the internal thread portion 52 and the external thread portion 51 may be screwed together.

[0054] If the adjustment leg 5 is mounted on the convex portion 41 of the housing base 4, the height position of the convex portion 41, i.e., the concave-convex portion 40, can be adjusted by rotating the internal thread portion 52. That is, the height adjustment mechanism 50 is formed by a pair of threaded portions, i.e., the external thread portion 51 and the internal thread portion 52, which are screw-fitted with each other. The height adjustment range h is the state in which the adjustment leg 5 is most shortened ( Figure 8 ) and the most extended state ( Fig. 9 ) is a design matter determined by the meshing range of the threads of the external thread portion 51 and the internal thread portion 52. The weight measuring device 1 of this embodiment has four protrusions 41, and the height position of the protrusions 41 can be adjusted by using the adjustment legs 5 provided on each of the four adjustment legs 5 to perform a leveling operation to set the weight measuring device 1 horizontally. Fig.10 This shows a state where the adjustment leg 5 is shortened to the minimum and the height position of the protrusion 41 is at the lowest.

[0055] (Variation Example)

[0056] Next, refer to Fig.11 , Fig.12 A modification of the adjustment leg 5 for adjusting the height of the weight measuring device 1 will be described. Fig.11 The adjustment leg 5 shown is a structure in which an external threaded portion 51 is fixed to the bottom of a convex portion 41 of a housing base 4 by a screw 14. The housing base 4 is provided with a threaded hole 41c for fastening the screw 14 to the bottom of the convex portion 41 instead of the engaging portion 41a formed around the base of the convex portion 41. In addition, the external threaded portion 51 is provided with a bottom plate 51c blocking the lower end of the cylindrical portion 51a instead of the engaging protrusion 51b protruding from the upper end of the cylindrical portion 51a. The bottom plate 51c has an insertion hole 51d for the screw 14 to pass through. The external threaded portion 51 is fixed to the convex portion 41 by fixing the bottom plate 51c to the bottom of the convex portion 41 by using the screw 14 that passes through the insertion hole 51d and is fastened to the threaded hole 41c. The bottom plate 51c for threaded connection is provided on the entire surface of the external threaded portion 51 in a manner that blocks one end of the cylindrical portion 51a of the external threaded portion 51.

[0057] Other modified examples of the adjustment leg 5 will be described. The external thread portion 51 only needs to be fixed to the convex portion 41 to prevent it from falling off and rotating. Fig.11 Therefore, Fig.12 As shown, a tongue piece 51e having a hole for inserting a screw may be provided at the bottom of the cylindrical portion of the external threaded portion 51. The tongue piece 51e may have a minimum area and thickness that provide the required strength. In addition, a recess is provided on the outer surface of the bottom of the convex portion 41, and the tongue piece 51e is engaged with the recess to fix the external threaded portion 51, thereby suppressing the increase in the leg length of the convex portion 41 and preventing rotation. In this case, the screw 14 may be replaced by an adhesive for fixing.

[0058] In addition, by separating the function of preventing the external thread portion 51 from falling off and the function of preventing rotation, they can be realized by a simple mechanism. For example, the falling off can be prevented by a snap-fit ​​structure composed of a simple screw and claw, and the rotation can be prevented by making the inner surface of the external thread portion 51 and the outer surface of the convex portion 41 have a combination structure of a keyway and a key, or a concave-convex snap-fit ​​structure.

[0059] In addition, as another modification of the adjustment leg 5, the external threaded portion 51 may not use the engaging protrusion 51b and the screw 14, but may be bonded and fixed to the outer periphery of the convex portion 41. In addition, the external threaded portion 51 may not be independent of the convex portion 41, but the thread groove and the thread teeth may be directly formed on the outer periphery of the convex portion 41 to form the external threaded portion 51. In this case, the thread groove and the thread teeth may be continuous or discontinuous for more than one turn of the thread. For example, the outer shape of the convex portion 41 may not be cylindrical but may be polygonal, and threads are provided on each edge of the polygonal column. More generally, a threaded structure that spirally cooperates with the internal threaded portion 52 is formed on the surface of the convex portion 41 so that the internal threaded portion 52 can be moved up and down along the length direction of the convex portion 41 by rotating the internal threaded portion 52.

[0060] In the weight measuring device 1 of the present embodiment, the signal from each force measuring element 3 is processed by the circuit substrate 6 to obtain the weight measurement result, and the weight measurement result is sent to the outside from the circuit substrate 6. The weight measuring device 1 may be provided with a display unit for displaying the weight measurement result integrally with the housing base 4. In this case, the housing base 4 may be provided with an extension portion extending to the outside of the housing cover 2 and the decorative cover 20 without interfering with the housing cover 2 and the decorative cover 20, and the extension portion may be provided with a display unit.

[0061] Alternatively, the weight measuring device 1 may not include a display unit integrally formed with the housing base 4, but may electrically connect the circuit board 6 to a display box provided independently of the housing base 4 via a wiring cable or wireless communication, and display the weight measurement result on the display unit of the display box.

[0062] According to the weight measuring device 1 of the present embodiment, the force measuring element 3 is fixed to the concave portion 42 opened upward of the concave-convex portion 40, and the adjustment leg 5 having the adjustment mechanism 50 for adjusting the height position is provided in the space at the position opposite to the side of the convex portion 41 protruding downward corresponding to the concave portion 42 of the concave-convex portion 40 provided on the housing base 4, that is, the side space 40b, so as to surround the concave-convex portion 40, thereby ensuring the prescribed performance and achieving a light and thin total thickness. In addition, the housing base 4 can be lightweight by the reinforced structure composed of the concave portion 42 and the convex portion 41 of the concave-convex portion 40, thereby ensuring the prescribed performance and providing the adjustment leg 5 without increasing the weight of the device.

[0063] (Second embodiment)

[0064] Fig.13(a) and (b) show the parts including the adjustment leg 5 and the force measuring element 3 of the weight measuring device 1 involved in the second embodiment of the present invention. The weight measuring device 1 of this embodiment reverses the mutual role of the external thread portion 51 and the internal thread portion 52 constituting the pair of thread portions of the first embodiment. That is, in the first embodiment, the external thread portion 51 is fixed to the housing base 4, and the internal thread portion 52 rotates to move up and down relative to the housing base 4, but in this embodiment, the internal thread portion 52 is fixed to the housing base 4, and the external thread portion 51 rotates to move up and down.

[0065] The external threaded portion 51 is a structure formed by integrating a cylindrical portion 51a having an external thread on the outer circumference, a bottom plate 51f forming a cover at the lower part of the cylindrical portion 51a, and a flange portion 51g in a shape extending outward from the bottom plate 51f. The external threaded portion 51 is configured to accommodate substantially the entire convex portion 41 of the concavo-convex portion 40 inside the cylindrical portion 51a.

[0066] The internal thread portion 52 is a structure formed by integrating a cylindrical thread portion 52a having an internal thread on the inner circumference of the cylinder and a mounting piece 52b protruding laterally from the upper end side of the cylindrical thread portion 52a. The mounting piece 52b has a through hole for inserting a rivet 52c. The internal thread portion 52 has a structure capable of accommodating the convex portion 41 of the concavo-convex portion 40 and the cylindrical portion 51a of the external thread portion 51 inside the cylindrical thread portion 52a, and is arranged in a space at a position opposite to the side of the concavo-convex portion 40 (convex portion 41) in order to accommodate them, that is, the side space 40b.

[0067] The internal thread portion 52 is fixed to the housing base 4 using a plurality of mounting pieces 52b and rivets 52c. The internal thread portion 52 is coaxial with the convex portion 41 of the concave-convex portion 40. The mounting piece 52b may be a plurality of individual tongue-shaped structures having through holes arranged around the upper end side of the cylindrical thread portion 52a, or may be a continuous flange. The fixing based on the mounting piece 52b and the rivet has the function of preventing the internal thread portion 52 from falling off from the housing base 4 and preventing the internal thread portion 52 from rotating when the internal thread portion 52 is screwed with the external thread portion 51.

[0068] The fixing of the internal threaded portion 52 to the housing base 4 is not limited thereto, and any fixing method that can prevent falling off and rotation can be used. For example, it can be fixed by screws. In addition, a protrusion can be provided on the upper end surface of the cylindrical threaded portion 52a, and a hole for the protrusion to be embedded can be provided on the housing base 4 to form a rotation prevention structure. In addition, the upper end of the cylindrical threaded portion 52a of the internal threaded portion 52 can also be provided with a structure for fixing the external threaded portion 51 of the first embodiment, that is, a plurality of engaging protrusions 51b as engaging protrusions for fixing the internal threaded portion 52 of this embodiment, instead of a fixing structure based on a mounting piece 52b and a rivet. In this case, a through hole, that is, an engaging portion, is provided on the housing base 4 for the engaging protrusion to be inserted for engagement.

[0069] The external thread portion 51 is screwed together with the internal thread portion 52 fixed to the housing base 4 and rotated, thereby forming an adjustment mechanism portion 50 that moves the external thread portion 51 up and down by using the mutual thread portions. For example, the user can rotate the external thread portion 51 by grasping the outer peripheral edge of the flange portion 51g with fingers. The adjustment range h of the height position is determined by the meshing range of the threads of the external thread portion 51 and the internal thread portion 52.

[0070] According to the weight measuring device 1 of the present embodiment, the force measuring element 3 is fixed to the concave portion 42 opened upward of the concave-convex portion 40, and the adjustment leg 5 having the adjustment mechanism 50 for adjusting the height position is provided in the space at the position opposite to the side of the convex portion 41 protruding downward corresponding to the concave portion 42 of the concave-convex portion 40 provided on the housing base 4, that is, the side space 40b, so as to surround the concave-convex portion 40, thereby ensuring the prescribed performance and achieving a light and thin total thickness. In addition, the housing base 4 can be lightweight by the reinforced structure composed of the concave portion 42 and the convex portion 41 of the concave-convex portion 40, thereby ensuring the prescribed performance and providing the adjustment leg 5 without increasing the weight of the device.

[0071] (Third embodiment)

[0072] Figure 14 to Figure 18The load cell unit 10 according to the third embodiment of the present invention is shown. The load cell unit 10 includes: a housing cover 102 for bearing the load of the object to be measured; a load cell 3 for supporting the housing cover 102 and detecting the load; a housing base 104 for storing the load cell 3; and an adjustment leg 5 for adjusting the height position of the housing base 104. The load cell unit 10 according to the third embodiment is a structure in which one load cell 3 in the weight measuring device 1 according to the first embodiment, a concavo-convex shape portion 40 for storing and fixing the load cell 3, an adjustment leg 5 corresponding to the concavo-convex shape portion 40, a housing cover 2 (102), and a portion around the load cell in the decorative cover 20 (120) are taken out and unitized. Therefore, the adjustment leg 5 has an adjustment mechanism portion 50 composed of a pair of threaded portions, namely, an external thread portion 51 and an internal thread portion 52, and is arranged in a side space 40b at a position opposite to the side portion 40a of the concavo-convex shape portion 40.

[0073] The housing base 104 includes: a concave-convex portion 40 having a concave portion 42 and a convex portion 41; and a flange portion 104a extending outward from the upper opening of the concave-convex portion 40 and having a circular outer shape. The force measuring element 3 is stored inside the concave portion 42 and fixed to the bottom. The external thread portion 51 of the adjustment leg 5 is retained on the outer periphery of the convex portion 41. The adjustment leg 5 is the same as the adjustment leg 5 of the first embodiment, except that four engaging protrusions 51b of the external thread portion 51 are formed at intervals of 90 degrees. The housing base 104 has slit-shaped engaging portions 41a formed on the side wall of the concave-convex portion surrounding the force measuring element 3 at four locations at intervals of 90 degrees corresponding to the engaging protrusions 51b of the external thread portion 51. The engaging portion 41 a opens on the upper surface of the flange portion 104 a of the housing base 104 , and the engaging protrusion 51 b of the external thread portion 51 engages with the opening edge 41 b thereof.

[0074] In addition, in the force sensor unit 10, the combination with the first embodiment can also be applied. Fig.11 , Fig.12 Various modifications of the adjustment leg 5 are described. The output from the flexible substrate 30b provided on the upper surface of the fixing portion 31 of the load cell 3 is taken out from the upper surface of the housing base 104 to the outside of the load cell unit 10 through the wiring 30c.

[0075] The housing cover 102 is a cover in the shape of a round bowl (tray) turned upside down, and is configured to cover the housing base 104 and the load cell 3 inside, and also covers the upper periphery of the adjustment leg 5. The housing cover 102 is fixed to the upper part of the load transfer member 33 of the load cell 3 by the screw 11. In order to reliably transfer the load borne by the upper part to the load cell 3, the housing cover 102 is configured to contact only the load transfer member 33 and not contact the fixed part, that is, the housing base 104, the wiring 30c and the adjustment leg 5.

[0076] The decorative cover 120 has a function as an appearance design component for adjusting the appearance of the force measuring cell unit 10 or as a component for protecting the force measuring cell unit 10, and does not need to be equipped with the force measuring cell unit 10. The decorative cover 120 has a shape that is closely attached to the housing cover 102 and covers the upper surface and side surfaces thereof. For example, the decorative cover 120 has engaging protrusions 2b at multiple locations on the inner surface of the lower end, and engages with the engaging notches 2a provided at the lower end of the housing cover 102 corresponding to the engaging protrusions 2b, and is fixed to the housing cover 102 and integrated.

[0077] The housing cover 102 and the decorative cover 120 have cutouts 2c and 20c for wiring lead-out on the side, respectively, and the wiring 30c can be led out to the outside without contacting the housing cover 102 and the decorative cover 120. The output signal from the force measuring element 3 outputted to the outside of the force measuring element unit 10 by the wiring 30c is transmitted to a control device (display box) that performs signal processing and display, etc., including the circuit substrate 6 of the first embodiment. The force measuring element unit 10 is connected to a display box that processes the output signal from the force measuring element 3, and is used in combination as a component constituting a weight measuring device, i.e., a platform scale.

[0078] In addition, the adjustment leg 5 having the adjustment mechanism 50 of the force sensor unit 10 is not limited to the structure shown in the present embodiment, and for example, it may be configured as the adjustment leg 5 of the second embodiment, in which the internal thread 52 is fixed to the housing base 104, and the external thread 51 is rotated to move up and down. In addition, the height adjustment mechanism 50 is not limited to being composed of a pair of threaded parts, and any height adjustment mechanism provided in the side space 40b at a position opposite to the side 40a of the concavo-convex portion 40 may be used.

[0079] According to the load cell unit 10 of this embodiment, the load cell 3 is fixed to the recessed portion 42 opened upward of the concave-convex portion 40, and the outer periphery of the convex portion 41 protruding downward corresponding to the recessed portion 42 of the concave-convex portion 40 provided on the housing base 104 has the adjustment legs 5 in a form of surrounding the load cell 3, so that a load cell unit that can achieve a light and thin total thickness while ensuring the specified performance is obtained. By combining and using a plurality of such load cell units 10, a thin weight measuring device having a stage of an arbitrary shape and a leveling function can be easily constructed.

[0080] (Weight measuring device using load cell unit)

[0081] Fig.19The weight measuring device 1 is a device that uses a load cell unit 10. The weight measuring device 1 includes: a plurality of (four in this embodiment) load cell units 10 arranged in a planar shape; and a common cover 20a placed on each housing cover 102 (or decorative cover 120) of the load cell unit 10 (see Fig.14 , Fig.16 as well as Fig.18 ) and the housing covers 102 (or decorative covers 120) are integrated with each other. The common cover 20a has a square plate shape and has load cell units 10 at four corners. The load cell units 10 have a function as support legs that share the load borne by the common cover 20a. The support legs can be adjusted in height using the adjustment legs 5 provided in the load cell units 10.

[0082] In addition, the weight measuring device 1 has a display box 10b connected to the wiring 30c drawn from each load cell unit 10. The display box 10b has a circuit for processing the output signal from each load cell unit 10 obtained through the wiring 30c to calculate the load applied to the common cover 20a, a processor, and a display for displaying the calculated load, etc. Such a weight measuring device 1 realizes a lightweight device with a leveling function.

[0083] The force measuring cell unit 10 of the weight measuring device 1 may not have the decorative cover 120, and the housing cover 102 may be directly fixed to the common cover 20a. The weight measuring device 1 of such a structure can combine any number of force measuring cell units 10 and fix them to a common cover 20a of any shape. For example, the common cover 20a may be formed into an elongated shape, a circular shape, a ring shape, etc. in accordance with the mutual contact structure between the measured object and the common cover 20a when the measured object is placed on the common cover 20a or the measured object is mounted on the common cover 20a. By using a unitized force measuring cell unit 10 having an adjustable leg 5 capable of adjusting the height, a lightweight weight measuring device 1 having a common cover 20a (carrier) of any shape can be easily realized.

[0084] The weight measuring device involved in the present invention may include a level gauge on the housing cover 2 and the housing base 4 for evaluating the leveling state when adjusting the height position (leveling) based on the adjustment leg 5. In addition, the weight measuring device and the force measuring element unit of the present invention may use a force measuring element of any other structure that can be at least partially accommodated in the concavo-convex portion 40 instead of the force measuring element 3 of the structure using the above-mentioned strain gauge.

[0085] In addition, the height adjustment mechanism 50 is not limited to a structure consisting of a pair of threaded parts that are screwed together in a manner of moving up and down, but may be a structure consisting of a combination of a pin and a groove or hole for sliding or fixing the pin. Figure 6 , Figure 7As shown, such an adjustment mechanism portion 50 is disposed in a side space 40 b existing at a position facing the side portion 40 a of the concavo-convex portion 40 .

[0086] To describe more generally. The adjustment leg 5 has an adjustment mechanism 50 for adjusting the height position. The adjustment mechanism 50 is a mechanism provided in the side space 40b located at a position opposite to the side portion 40a of the concave-convex portion 40, and includes a fixed member fixed to the housing base 4 and a movable member capable of moving up and down relative to the fixed member. The movable member can move up and down relative to the fixed member and can be fixed at a plurality of predetermined positions. The meaning of being able to be fixed means that the fixed state can be maintained even when the load of the object to be measured is applied in the fixed state.

[0087] In the case of such an adjustment mechanism 50 composed of a pin and a groove, the moving member and the fixed member are, for example, formed into a coaxial inner and outer double-layer cylindrical structure and fixed to a structure in which one side moves relative to the other side. The pin is, for example, erected from the inner surface of the cylinder toward the inside or from the outer surface of the cylinder toward the outside. The structure of the groove is designed to form a moving groove for the pin to move spirally on the inner surface or outer surface of the cylinder, to set a recess for the pin to sink into at an appropriate interval in the spiral groove, and to fix (stay) the pin by embedding the pin into the recess. When the pin is moved, the pin is lifted upward to escape from the recess. The spiral groove can be replaced by a stepped groove. An inclined recess for fixing the pin can be set on each step of the step. In addition, as another groove structure, for example, a manual transmission mechanism of an automobile can be learned, and the pin's vertical moving groove and multiple circumferential grooves for fixing the pin are set on the inner surface or outer surface of the cylinder, and these grooves can be combined to adjust the height position.

[0088] Description of reference numerals:

[0089] 1...weight measuring device; 10...force measuring cell unit; 2, 102...housing cover; 20a...common cover; 3...force measuring cell; 4, 104...housing base; 40...concave-convex shape portion; 40a...side portion; 40b...side space; 41...convex portion; 41a...engaging portion; 42...recessed portion; 5...adjusting leg; 50...adjusting mechanism portion; 51...external thread portion; 51a...cylindrical portion; 51b...engaging protrusion; 52...internal thread portion.

Claims

1. A weight measuring device, characterized in that: have: The housing cover bears the load of the measured object; A plurality of force measuring elements, supporting the housing cover and detecting the load; A housing base, wherein each of the plurality of force measuring elements has a concave-convex portion, wherein the concave-convex portion has a concave portion opening upward and a convex portion protruding downward corresponding to the concave portion, wherein a surface of the concave portion and a surface of the convex portion are in a front-back relationship with each other, and the concave-convex portion accommodates and fixes at least a part of the force measuring element in the concave portion; as well as The adjustment leg accommodates at least a part of the concavo-convex portion and has an adjustment mechanism for adjusting the height position at a position facing the side portion outside the concavo-convex portion.

2. The weight measuring device according to claim 1, characterized in that: The adjustment mechanism portion is a pair of threaded portions that are screwed together in a manner that allows for vertical movement.

3. The weight measuring device according to claim 2, characterized in that: The pair of threaded portions are an external threaded portion having a thread groove provided along the outer circumference of the side portion of the convex portion of the concavo-convex portion and an internal threaded portion screw-fitted with the external threaded portion to move up and down.

4. A force measuring element unit, characterized in that: have: Force measuring element, detecting the load of the measured object; The housing base has a concavo-convex portion, wherein the concavo-convex portion has a concave portion opening upward and a convex portion protruding downward corresponding to the concave portion, the surface of the concave portion and the surface of the convex portion are in a front-back relationship with each other, and the concavo-convex portion accommodates and fixes at least a part of the force measuring element in the concave portion; as well as The adjustment leg accommodates at least a part of the concavo-convex portion and has an adjustment mechanism for adjusting the height position at a position facing the side portion outside the concavo-convex portion.

5. The force measuring cell unit according to claim 4, characterized in that The adjustment mechanism portion is a pair of threaded portions that are screwed together in a manner that allows for vertical movement.

6. The force measuring cell unit according to claim 5, characterized in that The pair of threaded portions are an external threaded portion having a thread groove provided along the outer circumference of the side portion of the convex portion of the concavo-convex portion and an internal threaded portion screw-fitted with the external threaded portion to move up and down.

7. A weight measuring device, characterized in that: have: A plurality of force sensor units are arranged in a planar shape; and a common cover mounted on the plurality of force measuring cell units, The plurality of force measuring element units respectively include: Force measuring element, detecting the load of the measured object; The housing base has a concavo-convex portion, wherein the concavo-convex portion has a concave portion opening upward and a convex portion protruding downward corresponding to the concave portion, the surface of the concave portion and the surface of the convex portion are in a front-back relationship with each other, and the concavo-convex portion accommodates and fixes at least a part of the force measuring element in the concave portion; as well as The adjustment leg accommodates at least a part of the concavo-convex portion and has an adjustment mechanism for adjusting the height position at a position facing the side portion outside the concavo-convex portion.

8. The weight measuring device according to claim 7, characterized in that: The adjustment mechanism portion is a pair of threaded portions that are screwed together in a manner that allows for vertical movement.

9. The weight measuring device according to claim 8, characterized in that The pair of threaded portions are an external threaded portion having a thread groove provided along the outer circumference of the side portion of the convex portion of the concavo-convex portion and an internal threaded portion screw-fitted with the external threaded portion to move up and down.

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