Load detection mechanism and pin-type load sensor

Abstract

A load detection mechanism (100) for detecting the load of an object comprises: a first member (20) connected to a fixed structure; a second member (10) for suspending the object; pins (CP1, CP2) for suspending the second member on the first member by connecting the first member and the second member; a plurality of strain gauges (SG1 to SG8) mounted on the pins; and a circuit substrate (30) disposed on the second member. The circuit substrate comprises: a connection circuit (CC) for connecting the plurality of strain gauges to form a bridge circuit; and an amplifier circuit (AC) for amplifying the output from the bridge circuit.

Description

Technical Field

[0001] The invention relates to a load detection mechanism and a pin-type load sensor. Background Art

[0002] Among hoists such as cranes and chain blocks, there is known a hoist having a built-in load detector.

[0003] Patent document 1 discloses a technology for connecting a first connecting member and a second connecting member constituting a load transfer system of a crane or a mooring device with a connecting pin and detecting the magnitude of a relative load in the opposite direction applied between the first connecting member and the second connecting member by a strain gauge mounted on the connecting pin.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 8-201192 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Mechanisms equipped with connecting pins such as those disclosed in Patent Document 1 include large-scale ones used outdoors such as cranes and relatively small-scale ones used indoors, and the types and sizes of connecting pins equipped in each mechanism are different.

[0009] An object of the present invention is to provide a load detection mechanism capable of performing load detection using a relatively small pin-type member and a relatively small pin-type load sensor that can be used in the mechanism.

[0010] Solutions for solving problems

[0011] According to a first aspect of the present invention, there is provided a load detection mechanism for detecting the load of an object, characterized in that it comprises:

[0012] A first member connected to the fixed structure;

[0013] A second member for hanging the object;

[0014] a pin for suspending the second member from the first member by connecting the first member and the second member;

[0015] a plurality of strain gauges mounted on the pins; and

[0016] The circuit substrate is arranged on the second component.

[0017] The circuit substrate includes a connection circuit that connects the plurality of strain gauges to form a bridge circuit, and an amplifier circuit that amplifies an output from the bridge circuit.

[0018] In the load detection mechanism of the first aspect, a groove extending in the axial direction of the pin may be formed on the outer peripheral surface of the pin, and wiring connecting the plurality of strain gauges and the circuit board may be accommodated inside the groove.

[0019] In the load detection mechanism according to the first aspect, at least one of the first member and the second member may cover the groove.

[0020] In the load detection mechanism according to the first aspect, the circuit board may be arranged in a closed space defined inside the second member.

[0021] In the load detection mechanism according to the first aspect, one end of the pin may be located in the closed space, and the circuit board may be arranged below the one end.

[0022] In the load detection mechanism of the first aspect, at least one of the first member and the second member may be provided with an orientation adjusting portion for adjusting the orientation of the pin.

[0023] According to a second aspect of the present invention, there is provided a pin-type load sensor including a pin and a strain gauge mounted on the pin, wherein:

[0024] A groove for accommodating a wiring connecting the strain gauge and the outside is formed on the outer peripheral surface of the pin, and the groove extends along the axial direction of the pin.

[0025] Effects of the Invention

[0026] According to the load detection mechanism of the present invention, a smaller pin-type member can be used for load detection. In addition, the present invention can provide a smaller pin-type load sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a perspective view of an electric balancer according to an embodiment of the present invention.

[0028] Figure 2 : is an exploded perspective view of an electric balancer according to an embodiment of the present invention. Figure 2 The driving mechanism, suspension unit and control unit are omitted in the figure.

[0029] Figure 3 It is a three-dimensional diagram of a connecting pin.

[0030] Figure 4In the figure, (a) to (d) are cross-sectional views obtained by cutting the connecting pin at a plane perpendicular to the central axis. (a) is a cross-sectional view of a portion near the front end where the orientation adjustment surface is formed, (b) is a cross-sectional view of a portion of the front small diameter portion where the recess is formed, (c) is a cross-sectional view of a portion of the central large diameter portion where the central wiring groove is formed, and (d) is a cross-sectional view of a portion of the rear large diameter portion where the rear wiring groove is formed.

[0031] Figure 5 This is a partially enlarged cross-sectional view of the electric balancer cut along a plane including the central axis of the connecting pin and perpendicular to the width direction, and shows a state in which the connecting pin connects the main body portion and the hook portion.

[0032] Figure 6 This is an explanatory diagram for explaining a method of detecting a load using a pin-type load sensor.

[0033] Figure 7 This is a circuit diagram of a Wheatstone bridge circuit disposed inside an electric balancer. DETAILED DESCRIPTION

[0034] <Implementation Method>

[0035] Reference Figures 1 to 7 An electric balancer 100 according to an embodiment of the present invention will be described.

[0036] like Figure 1 , Figure 2 As shown, the electric balancer 100 mainly comprises: a main body 10; a hook 20; two connecting pins CP1 and CP2, connecting the main body 10 and the hook 20; eight strain gauges SG1 to SG8, ​​attached to each connecting pin CP1 and CP2 ( Figure 6 ); and a circuit substrate 30, which is disposed in the main body 10.

[0037] In the following description, the direction in which the main body 10 and the hook 20 are arranged is defined as the vertical direction of the electric balancer 100, and the side where the hook 20 is located is referred to as the upper side. In addition, among the in-plane directions of the orthogonal plane orthogonal to the vertical direction, the direction along the bending direction of the upper hook 21 (details will be described later) of the hook 20 is defined as the front-to-back direction of the electric balancer 100, and the direction orthogonal to the front-to-back direction is defined as the width direction of the electric balancer 100. In the front-to-back direction, the direction in which the upper hook 21 opens ( Figure 1 The left side and the right side when viewing the rear from the front are set as the left side and the right side in the width direction.

[0038] The main body 10 is a part that suspends the moving object and performs the lifting and lowering of the moving object. The main body 10 mainly includes a housing 11 , a driving mechanism 12 housed in the housing 11 , a suspension part 13 driven by the driving mechanism 12 , and a control part 14 that controls the driving mechanism 12 .

[0039] As an example, the box 11 is formed of steel material and has a box shape that opens downward. A drive mechanism accommodating space 11i is defined inside the box 11, and an opening 11a that connects the drive mechanism accommodating space 11i and the outside is defined at the lower end of the box 11.

[0040] A left convex wall WL is formed on the left side of the widthwise center of the upper surface 11t of the box body 11. The left convex wall WL is formed in a trapezoidal shape when viewed in the widthwise direction, and its lower bottom extends over the entire front-rear region of the upper surface 11t.

[0041] A right convex wall WR is formed on the right side of the widthwise center of the upper surface 11t of the box body 11. The right convex wall WR has the same shape as the left convex wall WL, is formed parallel to the left convex wall WL, and its lower bottom extends over the entire area of ​​the upper surface 11t in the front-rear direction.

[0042] A front convex wall WF and a rear convex wall WB are formed between the left convex wall WL and the right convex wall WR, standing upright from the upper surface 11t and extending in the width direction. The front convex wall WF and the rear convex wall WB have the same shape as each other, and are both substantially square when viewed in the front-to-back direction. The front convex wall WF and the rear convex wall WB are formed parallel to each other.

[0043] The left end of the front convex wall WF is connected to the vicinity of the front end of the left convex wall WL, and the right end of the front convex wall WF is connected to the vicinity of the front end of the right convex wall WR. In addition, the left end of the rear convex wall WB is connected to the vicinity of the rear end of the left convex wall WL, and the right end of the rear convex wall WB is connected to the vicinity of the rear end of the right convex wall WR.

[0044] Two connection holes H are formed in the front convex wall WF in a manner arranged in the width direction and penetrating the front convex wall WF in the front-to-back direction. Similarly, two connection holes H are formed in the rear convex wall WB in a manner arranged in the width direction and penetrating the rear convex wall WB in the front-to-back direction. The cross-sectional shape of the connection hole H of the front convex wall WF and the cross-sectional shape of the connection hole H of the rear convex wall WB are the same as each other, that is, circular. Figure 2 As shown, the two connection holes H of the front convex wall WF and the two connection holes H of the rear convex wall WB are aligned along the front-rear direction and are coaxially arranged.

[0045] A front space FS surrounded by the left convex wall WL, the right convex wall WR and the front convex wall WF is defined in front of the front convex wall WF. The front space FS is a triangular prism-shaped space with the width direction as the axial direction and opens obliquely upward and forward. The front space FS and the drive mechanism accommodating space 11i are separated by the upper surface 11t.

[0046] An orientation adjustment plate 11p is fixed to the front surface of the front convex wall WF. Figure 2 As shown, the orientation adjustment plate 11p is a substantially rectangular flat plate having two orientation adjustment holes Ho extending in the plate thickness direction. It should be noted that the orientation adjustment plate 11p may also be referred to as a "pin fixing plate" or the like. As described later, the pin fixing plate generally has the function of vertically aligning the strain gauge attachment surfaces (bottom surfaces of the recesses Rb and Rd) of the two connecting pins CP1 and CP2.

[0047] The cross section of each of the two orientation adjustment holes Ho has a shape in which two straight portions are cut out on the circumference. In this embodiment, when the orientation adjustment plate 11p is attached to the front convex wall WF, the straight portions facing each other extend in the vertical direction.

[0048] The orientation adjustment plate 11p is fixed to the front surface of the front convex wall WF by bolting through mounting holes (not shown). When the orientation adjustment plate 11p is mounted to the front convex wall WF, the two orientation adjustment holes Ho overlap with the two connection holes H of the front convex wall WF.

[0049] A central space CS surrounded by the left convex wall WL, the right convex wall WR, the front convex wall WF and the rear convex wall WB is defined behind the front convex wall WF. The central space CS is a substantially cubic space and opens upward. The central space CS and the drive mechanism housing space 11i are separated by an upper surface 11t.

[0050] A rear space BS surrounded by the left convex wall WL, the right convex wall WR and the rear convex wall WB is defined on the rear side of the rear convex wall WB. The rear space BS is a triangular prism-shaped space with the width direction as the axial direction, and opens obliquely upward and rearward through the opening BSa. The rear space BS and the drive mechanism accommodating space 11i are separated by the upper surface 11t.

[0051] A protective cover 11c is attached to the opening BSa so as to entirely cover the opening BSa. As an example, the protective cover 11c is a flat plate formed of the same material as the housing 11. The protective cover 11c may be fixed to the housing 11 by screws, bolts, or the like.

[0052] The drive mechanism 12 is disposed in the drive mechanism accommodating space 11i of the housing 11. The drive mechanism 12 mainly includes a motor, a transmission system, and a reel, all of which are not shown, and the drive mechanism 12 is configured so that the rotation of the motor is transmitted to the reel via the transmission system.

[0053] The hanging part 13 includes a chain 131 and a lower hook 132 connected to the lower end of the chain 131. The upper end of the chain 131 is wound around a reel (not shown) of the driving mechanism 12 through the opening 11a of the housing 11. Therefore, as the reel rotates, the length of the chain 131 hanging downward from the housing 11 changes, and the lower hook 132 moves up and down.

[0054] The control unit 14 is disposed in the drive mechanism housing space 11i of the housing 11. The control unit 14 controls the driving of the motor of the drive mechanism 12 based on input from an operator via a remote controller (not shown) or the like and input from the circuit board 30 (details will be described later).

[0055] The hook part 20 is a structure for hanging the electric balancer 100 from a fixed structure such as a beam. As an example, the hook part 20 is formed of a steel material.

[0056] The hook portion 20 mainly includes an upper hook 21 and a connecting base 22 connected to the lower end of the upper hook 21. The upper hook 21 and the connecting base 22 may be formed integrally.

[0057] The upper hook 21 may be any hook, and a hook with a latch may be used.

[0058] The connection base 22 is a solid body of a substantially cubic shape. Two connection holes H are formed in the connection base 22 so as to be aligned in the width direction and penetrate the connection base 22 in the front-rear direction. The cross-sectional shape of each of the two connection holes H is circular.

[0059] The connection base 22 is disposed inside the central space CS of the box 11 of the main body 10. The connection base 22 is disposed with respect to the main body 10 so that two connection holes H of the connection base 22 are coaxially aligned with two connection holes H of the front convex wall WF and two connection holes H of the rear convex wall WB.

[0060] The two connecting pins CP1 and CP2 are substantially cylindrical with a diameter of about 8 to 12 mm and a length of about 80 to 100 mm, and are arranged to connect the main body 10 and the hook 20 so that the connecting holes H communicate with each other. The connecting pins CP1 and CP2 have the same structure, so the following description focuses on the connecting pin CP1.

[0061] As an example, the connecting pin CP1 is formed of a steel material and has a substantially cylindrical shape having a central axis AX. The connecting pin CP1 is arranged inside the electric balancer 100. Figure 3 The left side of the electric balancer 100 is located at the front side of the electric balancer 100. Therefore, in the following description, for convenience, Figure 3 The left end of the connecting pin CP1 is set as the front end FE. Figure 3 The right end is set as the rear end BE of the connecting pin CP1.

[0062] The connecting pin CP1 is divided into a front large diameter portion CPa, a front small diameter portion CPb, a central large diameter portion CPc, a rear small diameter portion CPd, and a rear large diameter portion CPe from the front end FE toward the rear end BE.

[0063] The diameters of the front large diameter portion CPa, the central large diameter portion CPc, and the rear large diameter portion CPe are equal to each other, and as an example, are about 5 mm to 20 mm. The diameters of the front small diameter portion CPb and the rear small diameter portion CPd are equal to each other, and as an example, are about 1 mm to 5 mm smaller than the diameter of the front large diameter portion CPa.

[0064] In the region near the front end FE of the front large diameter portion CPa, a pair of orientation adjustment surfaces OS extending parallel to the central axis AX are formed by a pair of D-shaped cut portions. Figure 4 (a)).

[0065] A pair of recessed portions Rb ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ) are formed in the axial center of the front small diameter portion CPb in a radially opposed manner with the radial direction of the connecting pin CP1 as the depth direction. Figure 4 (b)). The shape of each recess Rb is substantially square when viewed in the radial direction. Each recess Rb is formed so that the bottom surface of the recess Rb is parallel to the orientation adjustment surface OS.

[0066] Similarly, a pair of recesses Rd are formed in the axial center of the rear small diameter portion CPd in ​​a radially opposed manner with the radial direction of the connecting pin CP1 as the depth direction. The shape of each recess Rd is substantially square when viewed in the radial direction. Each recess Rd is formed so that the bottom surface of the recess Rd is parallel to the orientation adjustment surface OS.

[0067] The outer peripheral surface of the connecting pin CP1 is formed with a pair of central wiring grooves WG1 extending axially from the pair of recesses Rb to the pair of recesses Rd, and a pair of rear wiring grooves WG2 extending axially from the pair of recesses Rd to the rear ends BE.

[0068] The pair of central wiring grooves WG1 and the pair of rear wiring grooves WG2 are also 180° apart in the circumferential direction of the connecting pin CP1. The pair of central wiring grooves WG1 and the pair of rear wiring grooves WG2 are formed at the same positions in the circumferential direction.

[0069] As described above, the two connecting pins CP1 and CP2 are respectively inserted into the connecting hole H of the front convex wall WF and the connecting hole H of the rear convex wall WB of the box body 11 of the main body 10 and the connecting hole H of the connecting platform 22 of the hook 20 to connect the main body 10 and the hook 20 ( Figure 5 ).

[0070] Specifically, the front large diameter portion CPa of the connecting pins CP1 and CP2 is inserted through the connecting hole H of the front convex wall WF of the box body 11 and is accommodated in the connecting hole H. The central large diameter portion CPc is inserted through the connecting hole H of the connecting platform 22 and is accommodated in the connecting hole H. The rear large diameter portion CPe is inserted through the connecting hole H of the rear convex wall WB and is accommodated in the connecting hole H. In this configuration, the front small diameter portion CPb of the connecting pins CP1 and CP2 is located between the rear surface of the front convex wall WF and the front surface of the connecting platform 22, and the rear small diameter portion CPd is located between the rear surface of the connecting platform 22 and the front surface of the rear convex wall WB.

[0071] The connecting pins CP1 and CP2 are arranged so that the bottom surfaces of the pair of recesses Rb of the front small diameter portion CPb and the bottom surfaces of the pair of recesses Rd of the rear small diameter portion CPd extend in the vertical direction. This arrangement can be easily performed by fitting the front ends FE of the connecting pins CP1 and CP2, which are formed with a pair of orientation adjustment surfaces OS, into the orientation adjustment holes Ho of the orientation adjustment plate 11p mounted on the front surface of the front convex wall WF. By using the orientation adjustment plate 11p, it is easier to form a hole shape suitable for orientation adjustment than in the case where the connecting hole H of the front convex wall WF of the main body 10 is set to a shape suitable for orientation adjustment.

[0072] Eight strain gauges SG1 to SG8 are mounted on each of the connecting pins CP1 and CP2.

[0073] Eight strain gauges SG1 to SG8 are attached to the bottom surface of a pair of recesses Rb of the front small diameter portion CPb in groups of two, and are attached to the bottom surface of a pair of recesses Rd of the rear small diameter portion CPd in ​​groups of two. Specifically, SG1 and SG2 are attached to the bottom surface of one of the pair of recesses Rb of the front small diameter portion CPb, and SG3 and SG4 are attached to the bottom surface of the other, and SG5 and SG6 are attached to the bottom surface of one of the pair of recesses Rd of the rear small diameter portion CPd, and SG7 and SG8 are attached to the bottom surface of the other.

[0074] like Figure 6As shown in FIG. 1 , the strain gauge SG1 is affixed to the bottom surface of one of the pair of recesses Rb in such a manner that its sensitive direction sd is oriented in a direction tilted 45° counterclockwise relative to the axial direction. The strain gauge SG2 is affixed adjacent to the strain gauge SG1 in such a manner that its sensitive direction sd is oriented in a direction tilted 45° clockwise relative to the axial direction. The strain gauge SG3 is affixed to the bottom surface of the other of the pair of recesses Rb in such a manner that its configuration and sensitive direction sd coincide with those of the strain gauge SG1 when viewed in the radial direction. The strain gauge SG4 is affixed to the bottom surface of the other of the pair of recesses Rb in such a manner that its configuration and sensitive direction sd coincide with those of the strain gauge SG2 when viewed in the radial direction.

[0075] Similarly, the strain gauge SG5 is affixed to one of the pair of recesses Rd so that its sensitive direction sd coincides with a direction tilted 45° clockwise relative to the axial direction. The strain gauge SG6 is affixed adjacent to the strain gauge SG5 so that its sensitive direction sd coincides with a direction tilted 45° counterclockwise relative to the axial direction. The strain gauge SG7 is affixed to the bottom surface of the other of the pair of recesses Rd so that its configuration and sensitive direction sd coincide with those of the strain gauge SG5 when viewed in the radial direction. The strain gauge SG8 is affixed to the bottom surface of the other of the pair of recesses Rd so that its configuration and sensitive direction sd coincide with those of the strain gauge SG6 when viewed in the radial direction.

[0076] The circuit board 30 is a printed board having wiring printed on an insulating substrate, and is installed on the upper surface 11t via a support pedestal 31 inside a rear space BS formed in the housing 11 of the main body 10. The printed wiring includes a connection wiring CC and an amplifier circuit AC.

[0077] By arranging the circuit substrate 30 in the rear space BS which is a closed space covered by the protective cover 11c, it is possible to prevent the circuit on the circuit substrate 30 from generating errors due to the influence of wind and humidity changes. In addition, the rear space BS is an independent space separated from the drive mechanism accommodating space 11i, so it is possible to prevent the circuit substrate 30 from generating errors due to vibrations of the motor and the like provided in the drive mechanism accommodating space 11i. In addition, by arranging the circuit substrate 30 on the support stand 31, heat can be efficiently dissipated from the circuit substrate 30.

[0078] The connection circuit CC is a circuit for connecting a plurality of strain gauges to form a Wheatstone bridge circuit. The connection circuit CC is connected to the strain gauges SG1 to SG8 attached to the connection pin CP1 and the strain gauges SG1 to SG8 attached to the connection pin CP2 via the wiring W. Thus, the strain gauges SG1 to SG8 attached to the connection pin CP1, the connection circuit CC, and the wiring W connecting them form a Wheatstone bridge circuit WSB1, and the strain gauges SG1 to SG8 attached to the connection pin CP2, the connection circuit CC, and the wiring W connecting them form a Wheatstone bridge circuit WSB2 ( Figure 7). In this way, by arranging the connection circuit CC on the main body 10 instead of on the connection pins CP1 and CP2, the diameters of the connection pins CP1 and CP2 can be reduced.

[0079] Wiring W( Figure 5 ) From each strain gauge SG1 to SG8, ​​through the central wiring groove WG1 and the rear wiring groove WG2, it reaches the rear end BE of the connecting pins CP1 and CP2, and extends from the rear end BE through the inside of the rear space BS to the circuit substrate 30. The circuit substrate 30 provided on the upper surface 11t is located below the rear ends BE of the connecting pins CP1 and CP2 of the connecting holes H arranged in the rear convex wall WB, so that the wiring drawn out from the connecting pins CP1 and CP2 can be easily connected to the connection circuit CC on the upper surface of the circuit substrate 30.

[0080] By routing the wiring W in this way, that is, by arranging the wiring W inside the central wiring groove WG1 and the rear wiring groove WG2 and covering the wiring W with the front convex wall WF, the connecting platform 22, and the rear convex wall WB, the wiring W is less susceptible to external interference, thereby suppressing the generation of noise in the wiring W.

[0081] The amplifier circuit AC is used to amplify the output voltage E from the Wheatstone bridge circuits WSB1 and WSB2. O A circuit for amplification.

[0082] The output sides of the Wheatstone bridge circuits WSB1 and WSB2 are connected to the input side of the amplifier circuit AC on the circuit board 30. The output side of the amplifier circuit AC is connected to the control unit 14 of the main body 10 via wiring (not shown).

[0083] Next, a method of using the electric balancer 100 according to the present embodiment will be described.

[0084] The movement of the moving object using the electric balancer 100 is performed in a state where the upper hook 21 of the hook portion 20 is hooked to a fixed structure such as a beam. The fixed structure on which the upper hook 21 is hooked may be movable in the horizontal direction. In the present invention and this specification, the "fixed structure" refers to a structure for holding the load detection structure in a manner suitable for the use when the load detection structure such as the electric balancer is used, and does not refer to a structure in which movement in all directions is fixed.

[0085] Next, the lower hook 132 of the hanging portion 13 of the main body 10 is hooked on the moving object. Specifically, for example, the lower hook 132 is hooked on the moving object placed on the ground, and the remote controller (not shown) is operated to wind up the chain 131 via the driving mechanism 12. As a result, the lower hook 132 moves upward, and the moving object also moves upward.

[0086] When the moving object is further moved upward while being suspended by the electric balancer 100, for example, the moving object is gently pushed upward by hand, the control unit 14 senses that the load applied to the electric balancer 100 by the moving object becomes smaller, and drives the driving mechanism 12 in the direction of winding up the chain 131 based on the sensing.

[0087] On the contrary, when the moving object is moved downward, for example, the moving object is gently pressed downward by hand, the control unit 14 senses that the load applied to the electric balancer 100 by the moving object becomes larger, and drives the driving mechanism 12 in the direction of pulling out the chain 131 based on the sensing.

[0088] The control unit 14 senses a change in the load applied to the electric balancer 100 by the moving object as described below.

[0089] When the magnitude of the load applied downward to the main body 10 changes in the state where the upper hook 21 of the hook portion 20 is hooked in the fixing structure, the deflection amount of the front small diameter portion CPb and the rear small diameter portion CPd of the connecting pins CP1 and CP2 changes. As a result, the outputs of the strain gauges SG1 to SG8 attached to the front small diameter portion CPb and the rear small diameter portion CPd change, and the output voltage Eo of the Wheatstone bridge circuits WSB1 and WSB2 also changes.

[0090] The control unit 14 receives the output voltage signal amplified by the amplifier circuit AC, and senses a change in the load based on a change in the output voltage signal.

[0091] Next, effects of the electric balancer 100 according to the present embodiment will be described.

[0092] In the electric balancer 100 of this embodiment, the connection circuit CC for configuring the Wheatstone bridge circuit is formed not on the connection pins CP1 and CP2 but on the circuit board 30 disposed in the case 11 of the main body 10. Therefore, the small connection pins CP1 and CP2 can be used as strain generating bodies.

[0093] Thus, the fact that the small connecting pins CP1 and CP2 can be used as strain generating bodies is advantageous in the following aspects: That is, the connecting pins that were originally not intended to be used as strain generating bodies but were designed to be small for design convenience can be used as strain generating bodies for load detection without making major design changes, thereby improving the degree of design freedom.

[0094] Note that by making the position of the circuit board 30 close to the connection pins CP1 and CP2 and shortening the wiring W, it is possible to suppress the generation of noise in the wiring W and improve the detection accuracy.

[0095] In the electric balancer 100 of the present embodiment, a central wiring groove WG1 and a rear wiring groove WG2 are formed on the surfaces of the connecting pins CP1 and CP2, and the wiring W connecting the strain gauges SG1 to SG8 and the connection circuit CC is accommodated inside the central wiring groove WG1 and the rear wiring groove WG2. Therefore, providing the grooves for wiring on the surfaces of the connecting pins CP1 and CP2 is advantageous in the following aspects.

[0096] That is, when a through hole for wiring is formed in the axial center of a small-diameter pin, it is not easy to form the through hole. For example, a drill with a very small diameter is required for processing, but a small-diameter drill is easily damaged and needs to be replaced frequently. Therefore, it takes cost and effort to manufacture a small-diameter pin with a through hole. In contrast, it is easier to form a groove on the outer peripheral surface, so the manufacturing cost can be suppressed.

[0097] In the electric balancer 100 of the present embodiment, the central large diameter portion CPc is arranged inside the connection hole H of the connection base 22 of the hook portion 20, and most of the wiring W accommodated in the central wiring groove WG1 is covered by the connection base 22. In addition, the rear large diameter portion CPe is arranged inside the connection hole H of the rear convex wall WB, and most of the wiring W accommodated in the rear wiring groove WG2 is covered by the rear convex wall WB. When the wiring W becomes longer, the signal in the wiring W is prone to generate noise due to the influence of wind and the like. By covering the wiring W with the connection base 22 and the like, the generation of noise in the wiring W is suppressed, and even if a Wheatstone bridge WSB with a long wiring length is formed, the noise can be suppressed from affecting the output voltage E of the Wheatstone bridge WSB. O impact.

[0098] In the electric balancer 100 of the present embodiment, the circuit board 30 is arranged inside the rear space BS which is a closed space covered by the protective cover 11c. In addition, the rear ends BE of the connecting pins CP1 and CP2 are also located in the rear space BS, and the wiring W extending from the rear ends BE to the circuit board 30 is also arranged inside the rear space BS. Therefore, the generation of noise in the wiring W extending from the rear ends BE to the circuit board 30 can be suppressed.

[0099] In summary, the electric balancer 100 of the present embodiment provides a design option of using a small connecting pin as a strain generator by providing the connecting circuit CC on the circuit substrate 30 on the main body 10 other than the connecting pins CP1 and CP2, and forming a wiring groove on the outer peripheral surface of the connecting pins CP1 and CP2. On the other hand, the electric balancer 100 of the present embodiment suppresses noise that may be generated by providing the connecting circuit CC at a position away from the connecting pins CP1 and CP2 and arranging the wiring W connecting the strain gauges SG1 to SG8 and the connecting circuit in the central wiring groove WG1 and the rear wiring groove WG2 that are open grooves by covering the wiring W with the main body 10 and the hook 20.

[0100] <Modification>

[0101] The electric balancer 100 of the above-described embodiment may also employ the following modifications.

[0102] In the electric balancer 100 of the above-mentioned embodiment, the front convex wall WF of the main body 10, the connecting platform 22 of the hook 20, and the rear convex wall WB of the main body 10 are arranged in sequence in the front-to-back direction, and the connecting pins CP1 and CP2 are inserted into the connecting holes H respectively provided on the front convex wall WF, the connecting platform 22 and the rear convex wall WB, thereby hanging the main body 10 from the hook 20, but it is not limited to this.

[0103] Specifically, for example, the front hanging portion of the upper hook, the convex portion on the top surface of the main body, and the rear hanging portion of the upper hook may be sequentially arranged in the front-to-back direction, and the connecting pin may be inserted through the connecting holes respectively provided in the front hanging portion, the convex portion, and the rear hanging portion, thereby hanging the main body from the hook. In this scheme, the orientation adjustment plate 11p may also be mounted on the front surface of the front hanging portion of the upper hook.

[0104] In addition, the connecting pin can connect the main body 10 and the hook 20 in any manner that allows the main body 10 and the hook 20 to communicate. It should be noted that in this specification and the present invention, the phrase "connecting a member having a pin (first member) and another member (second member)" includes all of the following schemes: a scheme in which the pin penetrates both the first member and the second member; a scheme in which the pin penetrates only one of the first member and the second member; and a scheme in which the pin is inserted into the first member and the second member without penetrating either of the first member and the second member.

[0105] In addition, the number of the connecting pins connecting the main body 10 and the hook 20 is not limited to two, and may be any number from one to three or more.

[0106] In the electric balancer 100 of the above embodiment, eight strain gauges SG1 to SG8 are mounted on each of the connecting pins CP1 and CP2, but the present invention is not limited thereto. The number of strain gauges attached to the connecting pins CP1 and CP2 can be set to any number. For example, when four strain gauges are attached to each of the connecting pins CP1 and CP2, a Wheatstone bridge is formed by the four strain gauges and the connecting circuit.

[0107] In the electric balancer 100 of the above embodiment, the circuit substrate 30 is arranged in the rear space BS of the box 11 of the main body 10, but the present invention is not limited thereto. The circuit substrate 30 can be arranged at any position on the main body 10. In addition, when the circuit substrate 30 is arranged in the rear space BS, the protective cover 11c is not necessary and can be omitted. In addition, regardless of the presence or absence of the protective cover 11c, the circuit substrate 30 is arranged in any closed space divided in the main body 10, thereby suppressing the error caused by wind and humidity changes in the circuit substrate 30.

[0108] In the electric balancer 100 of the above embodiment, the central wiring groove WG1 and the rear wiring groove WG2 for wiring W are arranged on the outer peripheral surface of the connecting pins CP1 and CP2, but the present invention is not limited thereto. Specifically, for example, a through hole along the axis of the connecting pins CP1 and CP2 may be provided and the through hole may be used as a passage for wiring W.

[0109] In the electric balancer 100 of the above-described embodiment, at least one of the body 10 and the hook 20 may be grounded by shielding the wire.

[0110] In the above embodiment, the electric balancer 100 having a solution of mounting strain gauges SG1 to SG8 on the connecting pins CP1 and CP2 is described as an example, but the present invention is not limited to this. The structure of the above embodiment in which the strain gauge is mounted on the connecting pin and the connection circuit is arranged at a position different from the connecting pin can also be adopted in any hoisting machine such as a chain pulley and a winch different from the electric balancer 100. In addition, any mechanism in which the strain gauge is mounted on the connecting pin and the connection circuit is arranged at a position different from the connecting pin can also be set as a load detection mechanism. Specifically, for example, in a mechanism having a first member and a second member, a strain gauge is mounted on a pin that suspends the second member from the first member by connecting the first member and the second member, and a connection circuit is formed on a circuit substrate arranged on the second member, wherein the first member is connected to a fixed structure for supporting the mechanism, and the second member is used to suspend an object as a measured body.

[0111] It should be noted that in the present invention and this specification, the phrase "a first member suspends" a second member does not necessarily mean that the first member "suspends" the second member in the direction of gravity, but means that the first member supports the second member in a manner that restricts the second member from moving in a specified direction. Therefore, for example, the following state is also included in the state where the first member suspends the second member: the second member connected to the first member by a pin is engaged with a moored ship via a wire rope, and the second member is restricted from moving by the first member while pulling the first member obliquely downward, obliquely upward, horizontally, etc.

[0112] <Second embodiment>

[0113] The connecting pins CP1 and CP2 included in the electric balancer 100 according to the above-described embodiment and the strain gauges SG1 to SG8 attached to the connecting pins CP1 and CP2 constitute the pin-type load sensor of the second embodiment of the present invention. In the pin-type load sensor of the second embodiment, the connecting pins CP1 and CP2 function as pin-type strain generating bodies. In addition, in the pin-type load sensor of the second embodiment, the number of strain gauges is an arbitrary number.

[0114] The pin-type load sensor of the second embodiment forms a path for extending the wiring led out from the strain gauge to the outside as a groove provided on the outer peripheral surface of the pin-type strain generating body instead of a through hole along the axis of the pin-type strain generating body. Therefore, the pin-type strain generating body can be miniaturized, and a smaller pin-type load sensor can be provided.

[0115] As long as the features of the present invention are maintained, the present invention is not limited to the above-described embodiment, and other embodiments considered within the technical idea of the present invention are also included in the scope of the present invention.

[0116] Description of Reference Numerals

[0117] 10: Main body portion; 11c: Protective cover; 11p: Azimuth adjustment plate; 20: Hook portion; 21: Upper hook; 22: Connecting table; 30: Circuit board; 100: Electric balancer; AC: Amplification circuit; CC: Connection circuit; CP1, CP2: Connecting pins; SG1 to SG8: Strain gauges; WSB1, WSB2: Wheatstone bridge circuits.

Claims

1. A load detection mechanism, detecting the load of an object, It is characterized in that have: A first member connected to the fixed structure; A second member for hanging the object; a pin for suspending the second member from the first member by connecting the first member and the second member; a plurality of strain gauges mounted on the pins; as well as The circuit substrate is arranged on the second component. The circuit substrate is provided with: a connection circuit for connecting the plurality of strain gauges to form a bridge circuit; and an amplifier circuit for amplifying the output from the bridge circuit, The pins include a first pin and a second pin, The plurality of strain gauges include a plurality of first strain gauges mounted on the first pins and a plurality of second strain gauges mounted on the second pins, The bridge circuit connects the plurality of first strain gauges to form a first bridge circuit and connects the plurality of second strain gauges to form a second bridge circuit. The second member has a box body, and the box body defines a driving mechanism accommodating space for accommodating a driving mechanism for moving the object inside the box body. The circuit substrate is arranged outside the box and in a closed space defined by the upper surface of the box, and the closed space is separated from the drive mechanism accommodating space. One end of the pin is disposed in the closed space.

2. The load detection mechanism according to claim 1, It is characterized in that A groove extending in the axial direction of the pin is formed on the outer peripheral surface of the pin, and wiring connecting the plurality of strain gauges and the circuit board is accommodated in the groove.

3. The load detection mechanism according to claim 2, It is characterized in that At least one of the first member and the second member covers the groove.

4. The load detection mechanism according to any one of claims 1 to 3, It is characterized in that The circuit substrate is arranged below the one end of the pin arranged in the closed space.

5. The load detection mechanism according to any one of claims 1 to 3, It is characterized in that An orientation adjusting portion for adjusting the orientation of the pin is mounted on at least one of the first member and the second member.

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