Force gauges and load measurement methods

Abstract

To provide a handheld force gauge capable of measuring load appropriately. [Solution] The force gauge 1 is a handheld force gauge comprising a housing 5, a measurement shaft 10 that protrudes from the housing 5 and is movable axially, a load cell disposed inside the housing 5 and to which a load is applied via the measurement shaft 10, an inertial sensor fixed to the housing 5, a control unit that determines the measured value of the load applied to the measurement shaft 10 based on the output of the load cell 11 and determines the amount of deviation of the attitude of the measurement shaft 10 from a predetermined reference attitude based on the output of the inertial sensor, and a display unit 14 that displays the amount of deviation of the attitude of the measurement shaft 10 determined by the control unit.

Description

[Technical Field]

[0001] The present invention relates to a handheld force gauge and a method for measuring a load using the same. [Background technology]

[0002] For example, handheld force gauges for measuring compressive loads and tensile loads are known, as described in Patent Documents 1 and 2. Typically, handheld force gauges include a measurement shaft and a load cell to which a load is applied via the measurement shaft.

[0003] As described in Patent Document 1, a handheld force gauge is equipped with a display unit that displays the measured value of the load. Furthermore, Patent Document 2 discloses that the display direction on the display unit is automatically inverted upside down depending on the orientation of the force gauge, allowing the operator to easily distinguish the measured value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-158469 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-263900 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, handheld force gauges have the advantage over stationary types in that they can measure loads easily regardless of the measurement location, but because they are handheld, there is a problem that it is difficult for the operator to measure while maintaining the measurement shaft in the desired measurement position.

[0006] For example, the operator cannot maintain the measurement shaft in a measurement position perpendicular to the surface of the object by relying solely on their sense, making it difficult to accurately measure a load applied perpendicular to the surface of the object.Furthermore, it is also difficult to accurately measure a load applied in a predetermined angular direction to the surface of the object by maintaining the measurement shaft at a predetermined measurement angle relative to the surface of the object.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to provide a force gauge that is handheld yet capable of appropriate load measurement. [Means for solving the problem]

[0008] The force gauge of the present invention is a handheld force gauge comprising a housing, a measurement shaft that protrudes from the housing and is movable axially back and forth, a load cell disposed inside the housing and to which a load is applied via the measurement shaft, an inertial sensor fixed to the housing, a control unit configured to determine a measured value of the load applied to the measurement shaft based on the output of the load cell and to determine the amount of deviation of the attitude of the measurement shaft from a predetermined reference attitude based on the output of the inertial sensor, and a display unit that displays the amount of deviation of the attitude of the measurement shaft determined by the control unit.

[0009] According to the above configuration, the control unit determines a load measurement value based on a load applied to the load cell via the measurement shaft. Here, the control unit determines the amount of deviation of the orientation of the measurement shaft from a predetermined reference orientation based on the output of the inertial sensor. For example, the reference orientation can be an orientation perpendicular to the surface of the measurement object.

[0010] The control unit displays the determined deviation of the posture of the measurement shaft on the display unit. Therefore, the operator can grasp the current posture of the measurement shaft by referring to the display unit. This allows, for example, measurement to be performed by operating the measurement shaft so that its posture coincides with the reference posture. On the other hand, it is also possible to perform measurement by operating the measurement shaft so that its posture is maintained at a constant posture different from the reference posture.

[0011] In this way, with the force gauge, it is possible to measure while maintaining the measurement shaft in a desired position based on the display on the display unit, so that appropriate load measurement is possible even though it is a handheld force gauge.

[0012] Furthermore, the control unit may be configured to determine the reference orientation based on an orientation of the measurement shaft that is taught before the load is measured and detected by the inertial sensor, thereby making it possible to appropriately set a reference orientation according to the measurement target.

[0013] Furthermore, the housing may have a plurality of reference surfaces that are perpendicular to one another, and the plurality of reference surfaces may be configured to be able to abut against the surface of the measurement object when teaching the attitude of the measurement shaft. This makes it possible to easily and appropriately set the reference attitude by using the reference surfaces of the housing.

[0014] Furthermore, the control unit may be configured to determine a correction value corresponding to the load when the attitude of the measurement shaft is the reference attitude based on the amount of deviation of the attitude of the measurement shaft from the reference attitude and the measured value of the load.

[0015] According to the above configuration, if the desired posture of the measurement shaft is set as the reference posture, even if the posture of the measurement shaft at the time of measurement deviates from the desired posture, the load that would be applied if the measurement shaft were in the desired posture can be obtained using a correction value.

[0016] Furthermore, the display unit may display a yaw reference circle indicating the amount of deviation of the measurement shaft in the yaw direction from the reference attitude, a pitch reference line which is a vertical axis extending in a diameter direction of the yaw reference circle and indicates the amount of deviation of the measurement shaft in the pitch direction from the reference attitude, a first position marker which is movable along the yaw reference circle and indicates the current position of the measurement shaft in the yaw direction, and a second position marker which is movable relative to the pitch reference line and indicates the current position of the measurement shaft in the pitch direction.

[0017] With this configuration, as the measurement shaft moves in the yaw direction, the first position marker moves along the yaw reference circle, and the amount of deviation of the measurement shaft in the yaw direction from the reference attitude is displayed based on the position of the first position marker relative to the yaw reference circle.

[0018] On the other hand, as the measurement shaft moves in the pitch direction, the second position marker moves relative to the pitch reference line on the vertical axis, and the position of the second position marker relative to the pitch reference line indicates the amount of deviation of the measurement shaft in the pitch direction from the reference attitude.

[0019] Such a display unit allows the user to intuitively grasp the amount of deviation of the measurement shaft in the yaw and pitch directions, making it possible to operate the force gauge easily and accurately.

[0020] Furthermore, the display unit may display a roll reference line, which is a horizontal axis extending in a diameter direction of the yaw reference circle and indicates a deviation amount of the measurement shaft in the roll direction from the reference attitude, and the second position marker may be movable with respect to the pitch reference line and the roll reference line and may simultaneously indicate the current position of the measurement shaft in the pitch direction and the current position of the measurement shaft in the roll direction.

[0021] With this configuration, as the measurement shaft moves in the pitch direction, the second position marker moves relative to the pitch reference line on the vertical axis, and the amount of deviation of the measurement shaft in the pitch direction from the reference attitude is displayed based on the position of the second position marker relative to the pitch reference line.

[0022] Furthermore, as the measurement shaft moves in the roll direction, the second position marker moves relative to the roll reference line on the horizontal axis, and the position of the second position marker relative to this roll reference line indicates the amount of deviation of the measurement shaft in the roll direction from the reference attitude.

[0023] Therefore, since one position marker simultaneously displays both the current pitch direction position and the current roll direction position of the measurement shaft, it is possible to easily grasp the amount of deviation of the measurement shaft in the pitch direction and the roll direction.

[0024] Furthermore, a method for measuring a load according to the present invention is a method for measuring a load using a handheld force gauge, the force gauge comprising a housing to which an inertial sensor is fixed, a measurement shaft that protrudes from the housing and is movable axially, and a control unit and a display unit provided on the housing, the method including the steps of: an operator instructing the force gauge on the attitude of the measurement shaft, and the control unit determining a reference attitude based on the output of the inertial sensor; the control unit determining an amount of deviation of the attitude of the measurement shaft from the reference attitude based on the output of the inertial sensor; a display unit displaying the amount of deviation of the attitude of the measurement shaft determined by the control unit; and the operator measuring the load applied to the measurement shaft by moving the housing so as to maintain the attitude of the measurement shaft consistent with the reference attitude, while referring to the amount of deviation of the attitude of the measurement shaft from the reference attitude displayed on the display unit.

[0025] According to the above configuration, when measuring a load using a handheld force gauge, an operator first teaches the force gauge the orientation of the measurement shaft, and the inertial sensor detects the orientation of the measurement shaft. The control unit determines a reference orientation based on the output of the inertial sensor. For example, the reference orientation can be set to coincide with a desired orientation of the measurement shaft.

[0026] Next, when the operator moves the housing to a predetermined orientation, the inertial sensor detects the orientation of the measurement shaft, and the control unit determines the amount of deviation of the orientation of the measurement shaft from the reference orientation. The amount of deviation is then displayed on the display unit. By referring to the display, the operator can accurately grasp the current orientation of the measurement shaft from the reference orientation. The operator can then move the housing so that the orientation of the measurement shaft remains consistent with the reference orientation, thereby appropriately measuring the load.

[0027] Furthermore, a method for measuring a load according to the present invention is a method for measuring a load using a handheld force gauge, the force gauge comprising: a housing to which an inertial sensor is fixed; a measurement shaft that protrudes from the housing and is movable axially; and a control unit and a display unit provided on the housing, the method including the steps of: an operator instructing the force gauge on the orientation of the measurement shaft, and the control unit determining a reference orientation based on the output of the inertial sensor; the control unit determining an amount of deviation of the orientation of the measurement shaft from the reference orientation based on the output of the inertial sensor; the display unit displaying the amount of deviation of the orientation of the measurement shaft determined by the control unit; and the operator measuring the load applied to the measurement shaft by moving the housing while referring to the amount of deviation of the orientation of the measurement shaft from the reference orientation displayed on the display unit, thereby maintaining the orientation of the measurement shaft consistent with a desired measurement orientation different from the reference orientation.

[0028] With the above configuration, the control unit also determines the amount of deviation of the measurement shaft's attitude from the reference attitude, and the amount of deviation is displayed on the display unit. Here, the reference attitude can be set to be different from the desired attitude of the measurement shaft. The operator refers to the display and moves the housing so that the attitude of the measurement shaft is maintained in agreement with the desired measurement attitude that is different from the reference attitude. This allows appropriate measurement to be performed while maintaining the measurement shaft in the desired attitude. [Effects of the Invention]

[0029] According to the present invention, it is possible to provide a force gauge that is handheld and yet allows appropriate load measurement while maintaining the measurement shaft in a desired position. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a front view showing the appearance of the force gauge. [Figure 2] FIG. 2 is a side view showing the appearance of the force gauge. [Figure 3] FIG. 3 is a perspective view showing the appearance of the force gauge. [Figure 4] FIG. 4 is a front view showing the internal configuration of the housing of the force gauge. [Figure 5] FIG. 5 is a block diagram showing the configuration of the force gauge. [Figure 6] FIG. 6 is an enlarged view showing the display unit. [Figure 7] FIG. 7 is an explanatory diagram showing the reference attitude in a measurement example of the first embodiment. [Figure 8] FIG. 8 is an explanatory diagram showing a method for determining the reference attitude in the first embodiment. [Figure 9] FIG. 9 is an enlarged view of the reference circle and the reference line on the display unit. [Figure 10] FIG. 10 is a display diagram showing the deviation amount of the attitude of the measurement shaft relative to the reference attitude. [Figure 11]FIG. 11 is a diagram showing a state in which the attitude of the measurement shaft coincides with the reference attitude. [Figure 12] FIG. 12 is an explanatory diagram showing an example of measurement of the tensile load when the draw-out portion of the first embodiment is drawn out straight. [Figure 13] FIG. 13 is an explanatory diagram showing the relationship between the measurement value and the correction value. [Figure 14] FIG. 14 is a flowchart showing the measurement method in the first embodiment. [Figure 15] FIG. 15 is an explanatory diagram showing an example of measurement of the tensile load when the draw-out portion of the second embodiment is drawn out in an oblique direction. [Figure 16] FIG. 16 is a flowchart showing a measurement method in the second embodiment. [Figure 17] FIG. 17 is an explanatory diagram showing a method for determining the reference attitude in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. First Embodiment

[0032] 1 to 3 show the external appearance of the force gauge 1 in the first embodiment. Fig. 4 shows the internal configuration of the housing 5 of the force gauge 1. The force gauge 1 is a handheld force gauge that measures compressive loads and tensile loads. Note that the force gauge 1 may be configured to measure at least one of compressive loads and tensile loads.

[0033] 1 to 4, the force gauge 1 includes a housing 5, a measurement shaft 10, a load cell 11, an inertial sensor 12, a control unit 13, and a display unit 14. Although not shown, the force gauge 1 further includes a memory, a power supply circuit, and other components.

[0034] The measurement shaft 10 is disposed on top of the housing 5 and is provided so as to be movable in the axial direction of the measurement shaft 10 while protruding from the housing 5. The measurement shaft 10 is supported by the housing 5 so that its posture matches the posture of the housing 5. A load is applied to the tip of this measurement shaft 10. A jig (not shown) according to the measurement method and the object to be measured can be attached to the tip of the measurement shaft 10. For example, when measuring a tensile load, a jig that can be fixed to the object to be measured is attached to the tip of the measurement shaft 10.

[0035] The housing 5 has gripping sections 15 formed with narrow central sections on both the left and right sides to make it easier for the operator to grip. The housing 5 has a front section 20 on which the display section 14 is arranged, side sections 21a and 21b on both the left and right sides, a bottom section 22 arranged on the opposite side from the measurement shaft 10, and a back section 23 arranged on the opposite side from the front section 20.

[0036] As shown in FIG. 1, two side surface portions 21a are arranged on one side surface of the housing 5 so as to sandwich the grip portion 15 therebetween. The two side surface portions 21a are arranged along the same plane A. Similarly, two side surface portions 21b are arranged on the other side surface of the housing 5 so as to sandwich the grip portion 15 therebetween. The two side surface portions 21b are arranged along the same plane B. The two planes A and B are parallel to each other.

[0037] The bottom surface portion 22 forms a plane C that is perpendicular to the planes A and B. Furthermore, as shown in FIG. 2, the rear surface portion 23 forms a plane D that is perpendicular to the planes A, B, and plane C. That is, in the housing 5, the side surfaces 21a and 21b, the bottom surface portion 22, and the rear surface portion 23 are perpendicular to one another. The axis of the measurement shaft 10 is parallel to the planes A, B, and plane D, and perpendicular to plane C. Note that a plurality of connectors (not shown) are arranged in the housing 5, recessed from the plane C of the bottom surface portion 22.

[0038] 4, the load cell 11 is disposed inside the housing 5 and configured so that a load is applied via the measurement shaft 10. Although not shown, the load cell 11 includes a load cell main body having a plurality of strain gauges.

[0039] The inertial sensor 12 is fixedly provided inside the housing 5. Examples of the inertial sensor 12 provided in the housing 5 include an acceleration sensor, a gyro sensor, and a motion sensor. The inertial sensor 12 can detect the attitude of the housing 5 (i.e., the attitude of the measurement shaft 10).

[0040] Fig. 5 is a block diagram showing the configuration of the force gauge 1. Fig. 6 is an enlarged view showing the display unit 14. As shown in Fig. 5, the control unit 13 is configured to determine a measurement value of the load applied to the measurement shaft 10 based on the output of the load cell 11.

[0041] 6, the display unit 14 displays the determined current load measurement value 26 in real time. The display unit 14 also displays the peak value 27 of the compressive load measured during the measurement time and the peak value 28 of the tensile load measured during the measurement time.

[0042] 7 and 8 show an example of a measurement method in this embodiment 1. As shown in Fig. 7, in this measurement example of this embodiment 1, the load applied when opening or closing the drawer 8, which slides with one degree of freedom in the front-to-rear direction relative to the main body 7, is measured by a force gauge 1. The front surface 8a of the drawer 8 has a plane that is perpendicular to the sliding direction S of the drawer 8.

[0043] 8, the top surface 7a and the side surface 7b of the main body 7 form planes perpendicular to each other and extend along the sliding direction S. That is, the top surface 7a and the side surface 7b are planes perpendicular to the front surface 8a of the drawer 8.

[0044] As shown in Fig. 8, the force gauge 1 is configured so that an operator can teach multiple postures of the measurement shaft 10 in order to determine a reference posture of the measurement shaft 10. When teaching multiple postures of the measurement shaft 10, the side surfaces 21a and 21b, bottom surface 22, and rear surface 23 of the housing 5 serve as reference surfaces that can abut against the surface of the measurement object. In the example shown in Fig. 8, the rear surface 23 of the housing 5 abuts against the top surface 7a of the main body 7, and the side surface 21a of the housing 5 abuts against the side surface 7b of the main body 7.

[0045] The taught orientations of the measurement shaft 10 are detected by the inertial sensor 12. As shown in Fig. 5, the control unit 13 is configured to determine the reference orientation of the measurement shaft 10 based on the output of the inertial sensor 12. In the first embodiment, an orientation along the sliding direction S as shown in Fig. 7 can be set as the reference orientation of the measurement shaft 10.

[0046] The reference posture is a reference posture of the measurement shaft 10 during load measurement. The yaw angle Yr, roll angle Rr, and pitch angle Pr of the reference posture are all set to 0°. On the other hand, the yaw angle Y, roll angle R, and pitch angle P, which represent the posture of the measurement shaft 10 during load measurement, are angles based on the yaw angle Yr, roll angle Rr, and pitch angle Pr of the reference posture.

[0047] Therefore, the yaw angle Y, roll angle R, and pitch angle P of the measurement shaft 10 represent the deviation amounts (deviation angles) from the yaw angle Yr, roll angle Rr, and pitch angle Pr of the reference attitude, respectively. The control unit 13 is configured to determine the deviation amount of the current attitude of the measurement shaft 10 from the reference attitude based on the output of the inertial sensor 12.

[0048] 6, the display unit 14 is configured to display the amount of deviation of the current posture of the measurement shaft 10 from the determined reference posture. Here, FIGS. 9 to 11 are enlarged views of the guide display 40 on the display unit 14.

[0049] 6, the display unit 14 numerically displays the current yaw angle value 32, roll angle value 33, and pitch angle value 34 relative to the reference attitude as deviation amounts of the current attitude of the measurement shaft 10 relative to the reference attitude. Furthermore, the display unit 14 graphically displays the deviation amounts of the current attitude of the measurement shaft 10 relative to the reference attitude as a guide display 40.

[0050] As shown in FIGS. 9 to 11, the guide display 40 includes a yaw reference circle 41, a pitch reference line 42, a roll reference line 43, a first position marker 45, and a second position marker 46.

[0051] The yaw reference circle 41 indicates the amount of deviation of the measurement shaft 10 in the yaw direction from the reference attitude. The yaw reference circle 41 includes an angle scale that displays the yaw angle. The first position marker 45 is movable along the yaw reference circle 41 and indicates the current position of the measurement shaft 10 in the yaw direction (yaw angle Y). The first position marker 45 is displayed so as to move in real time in response to changes in the attitude of the measurement shaft 10 in the yaw direction. On the other hand, the second position marker 46 is displayed so as to move in real time in accordance with changes in the attitude of the measurement shaft 10 in the pitch and roll directions.

[0052] Here, the intersection of the yaw reference circle 41 and the upper end of the pitch reference line 42 is the first origin 51. As shown in FIG. 11, when the first position marker 45 is positioned corresponding to the first origin 51, the attitude of the measurement shaft 10 coincides with the reference attitude in the yaw direction (yaw angle Y = 0). Also, as shown in FIG. 10, the farther the first position marker 45 is positioned to the left from the first origin 51, the greater the deviation of the tip of the measurement shaft 10 to the right in the yaw direction. On the other hand, the farther the first position marker 45 is positioned to the right from the first origin 51, the greater the deviation of the tip of the measurement shaft 10 to the left in the yaw direction.

[0053] The pitch reference line 42 is a vertical axis extending in the diameter direction of the yaw reference circle 41 and indicates the deviation of the measurement shaft 10 in the pitch direction from the reference attitude. The pitch reference line 42 includes an angle scale indicating the pitch angle. Meanwhile, the roll reference line 43 is a horizontal axis extending in the diameter direction of the yaw reference circle 41 and indicates the deviation of the measurement shaft 10 in the roll direction from the reference attitude. The roll reference line 43 includes an angle scale indicating the roll angle.

[0054] The second position marker 46 is movable relative to the pitch reference line 42 and the roll reference line 43, and simultaneously indicates the current position of the measurement shaft 10 in the pitch direction (pitch angle P) and the current position of the measurement shaft 10 in the roll direction (roll angle R).

[0055] Here, the intersection of the pitch reference line 42 and the roll reference line 43 is the second origin 52. As shown in Fig. 11, when the second position marker 46 is at the second origin 52, it indicates that the attitude of the measurement shaft 10 matches the reference attitude in both the pitch direction and the roll direction (pitch angle P = 0 and roll angle R = 0).

[0056] With regard to the pitch direction, when the second position marker 46 is on the roll reference line 43, it indicates that the attitude of the measurement shaft 10 matches the reference attitude in the pitch direction (pitch angle P = 0). Also, as shown in Fig. 10, the further the second position marker 46 is positioned above the roll reference line 43, the greater the downward deviation of the tip of the measurement shaft 10 in the pitch direction. On the other hand, the further the second position marker 46 is positioned below the roll reference line 43, the greater the upward deviation of the tip of the measurement shaft 10 in the pitch direction.

[0057] With regard to the roll direction, when the second position marker 46 is on the pitch reference line 42, it indicates that the attitude of the measurement shaft 10 coincides with the reference attitude in the roll direction (roll angle R = 0). Also, as shown in Fig. 10, the further the second position marker 46 is positioned to the right from the pitch reference line 42, the greater the deviation of the measurement shaft 10 to the right in the roll direction. On the other hand, the further the second position marker 46 is positioned to the left from the pitch reference line 42, the greater the deviation of the measurement shaft 10 to the left in the roll direction.

[0058] By referring to the guide display 40, the operator can intuitively grasp the amount of deviation of the posture of the measurement shaft 10 from the reference posture, which makes it possible to maintain the measurement shaft 10 in a desired posture and measure the load appropriately.

[0059] The force gauge 1 in this embodiment 1 further has a function of correcting the measured value of the load. Here, Fig. 12 is an explanatory diagram showing an example of measuring the tensile load when the drawer portion 8 in this embodiment 1 is pulled out straight. Fig. 13 is an explanatory diagram showing the relationship between the measured value and the correction value.

[0060] 12, when the posture of the measurement shaft 10 matches the reference posture (the posture along the sliding direction S), the load K measured by the measurement shaft 10 matches the load L required to move the drawer section 8. Therefore, the load L can be measured accurately.

[0061] On the other hand, as shown in Figure 13, when the posture of the measurement shaft 10 does not match the reference posture (the posture in the sliding direction S), the load K measured by the measurement shaft 10 becomes larger than the load L required to move the drawer section 8.

[0062] Therefore, the control unit 13 determines a correction value corresponding to the load when the attitude of the measurement shaft 10 is the reference attitude based on the deviation amount (yaw angle Y, roll angle R, and pitch angle P) of the attitude of the measurement shaft 10 from the reference attitude and the measured value of the load. The correction value can be calculated for each of the axes of the yaw angle Y, roll angle R, and pitch angle P using trigonometric functions.

[0063] As shown in Fig. 6, the display unit 14 displays the correction value 36 determined by the control unit 13. Therefore, in the first embodiment, even if the posture of the measurement shaft 10 during load measurement does not exactly match the reference posture, a correction value obtained by correcting the measurement value can be obtained. The force gauge 1 is configured so that the operator can select a mode in which the correction value is not determined or displayed. -Load measurement method-

[0064] Next, an example of a method for measuring a load using the force gauge 1 will be described with reference to Figures 7 to 8 and 12 to 14. Here, Figure 14 is a flowchart showing the measurement method in the first embodiment.

[0065] 7 and 8, in the present embodiment 1, the load when opening or closing the drawer section 8, which slides with one degree of freedom in the front-to-rear direction relative to the main body 7, is measured by the force gauge 1. In particular, in the present embodiment 1, an example will be described in which the housing 5 is moved so that the posture of the measurement shaft 10 coincides with the reference posture to obtain a measurement value.

[0066] First, the operator selects whether or not to measure the load using the guide display 40. If the guide display 40 is not used, the display unit 14 goes into a mode in which the measured value of the load is displayed numerically on the display unit 14.

[0067] On the other hand, if the operator selects to measure the load using the guide display 40, the measurement is performed according to the flowchart in Fig. 14. First, in step S1, the control unit 13 switches the display unit 14 to a mode that displays a display including the guide display 40, in response to the operator's selection. As a result, the yaw reference circle 41, pitch reference line 42, and roll reference line 43 are displayed on the display unit 14, as shown in Fig. 9.

[0068] At this time, the control unit 13 may determine the amount of deviation of the attitude of the measurement shaft 11 from a preset default reference attitude, and the determined amount of deviation of the attitude may be displayed on the display unit 14 using the first position marker 45 and the second position marker 46 described below.

[0069] Next, in step S2, the reference posture of the measurement shaft 10 is determined. As shown in FIG. 8, the operator first teaches the posture of the measurement shaft 10 to the force gauge 1, for example, by abutting the rear surface 23 of the housing 5 against the upper surface 7a of the main body 7. The taught posture of the measurement shaft 10 is detected by the inertial sensor 12. At this time, the axis of the measurement shaft 10 is parallel to the upper surface 7a of the main body 7, so the pitch angle P of the measurement shaft 10 matches the pitch angle Pr of the reference posture. Therefore, the pitch angle Pr of the reference posture can be set (Pr = 0°). The posture of the measurement shaft 10 matches the posture of the housing 5.

[0070] Next, the posture of the measurement shaft 10 is taught by abutting the side surface 21a of the housing 5 against the side surface 7b of the main body 7. At this time, the axis of the measurement shaft 10 becomes parallel to the side surface 7b of the main body 7, so the yaw angle Y of the measurement shaft 10 coincides with the yaw angle Yr of the reference posture. Therefore, the yaw angle Yr of the reference posture can be set (Yr = 0°). However, the pitch angle P of the measurement shaft 10 at this time may differ from the pitch angle Pr set earlier. Therefore, by setting the yaw angle Yr of the reference posture while keeping the pitch angle P displayed on the display unit 14 at 0° (= Pr), both the pitch angle Pr and the yaw angle Yr of the reference posture can be set. In addition, the roll angle R of the measurement shaft 10 at this time is set as the roll angle Rr of the reference posture.

[0071] In this way, the control unit 13 determines the reference attitude of the measurement shaft 10 based on the output of the inertial sensor 12. In the first embodiment, based on two taught attitudes of the measurement shaft 10 along two mutually perpendicular planes (the upper surface 7a and the side surface 7b of the main body 7), the reference attitude of the measurement shaft 10 can be set to an attitude along the sliding direction S as shown in FIG.

[0072] Next, in step S3, the control unit 13 determines the amount of deviation of the attitude of the measurement shaft 10 from the reference attitude. That is, the control unit 13 detects the current attitude of the measurement shaft 10 based on the output of the inertial sensor 12. Then, based on the detected current attitude of the measurement shaft 10 and the reference attitude, the control unit 13 determines the amount of deviation of the attitude of the measurement shaft 10 from the reference attitude. The amount of deviation of the attitude of the measurement shaft 10 is the yaw angle Y, pitch angle P, and roll angle R of the current measurement shaft 10 from the reference attitude.

[0073] Subsequently, in step S4, the control unit 13 displays the deviation amount of the attitude of the measurement shaft 10 from the reference attitude on the display unit 14. That is, as shown in Fig. 6, the display unit 14 displays the deviation amount of the current attitude of the measurement shaft 10 from the reference attitude (yaw angle value 32, roll angle value 33, and pitch angle value 34) numerically.

[0074] 6 and 10, the control unit 13 graphically displays the deviation amount of the current attitude of the measurement shaft 10 on the display unit 14 as a guide display 40. That is, the control unit 13 displays on the display unit 14, in addition to a yaw reference circle 41, a pitch reference line 42, and a roll reference line 43, a first position marker 45 indicating the current position of the measurement shaft 10 in the yaw direction, and a second position marker 46 indicating the current positions of the measurement shaft 10 in the pitch direction and the roll direction.

[0075] Next, in step S5, the operator, while referring to the deviation of the attitude of the measurement shaft 10 from the reference attitude displayed on the display unit 14, moves the housing 5 so that the attitude of the measurement shaft 10 remains consistent with the reference attitude. This measures the load applied to the measurement shaft 10. The control unit 13 displays a measured value 26 of the current load on the display unit 14. As shown in FIG. 12, when the attitude of the measurement shaft 10 matches the reference attitude, the attitude of the measurement shaft 10 matches the sliding direction S of the drawer unit 8, and therefore the measurement load K of the measurement shaft 10 matches the load L required to move the drawer unit 8. Therefore, the load L can be measured accurately.

[0076] Next, in step S6, the control unit 13 determines whether the deviation amount of the attitude of the measurement shaft 10 is equal to or less than a preset threshold angle. The threshold angle can be set arbitrarily by the operator. In addition, the threshold angle can be set for each of the yaw angle Y, roll angle R, and pitch angle P of the measurement shaft 10.

[0077] If the deviation amount of the posture of the measurement shaft 10 is larger than the threshold angle, the process proceeds to step S7 and the measured value of the load is not corrected. Subsequently, in step S8, the measured value of the load is displayed on the display unit 1. Thereafter, the control unit 13 returns to step S3.

[0078] On the other hand, if the deviation amount of the posture of the measurement shaft 10 is equal to or less than the threshold angle in step S6, the process proceeds to the next step S9, where the control unit 13 determines a correction value. By setting the threshold angle in this way, it becomes possible to determine an appropriate correction value.

[0079] In step S9, the control unit 13 determines a correction value for correcting the measured value based on the deviation of the attitude of the measurement shaft 10 from the reference attitude and the measured value of the load. The correction value is a value corresponding to the load when the attitude of the measurement shaft 10 is the reference attitude. Subsequently, in step S10, the display unit 14 displays the measured values 26, 27, and 28 of the load and the correction value 36.

[0080] Thereafter, the control unit 13 returns to step S3 and repeats the processes from step S3 to step S10 to determine the load measurement values 26, 27, 28 and the correction value 36 in real time and display them on the display unit 14.

[0081] As described above, in this embodiment 1, the deviation amount (yaw angle Y, roll angle R, and pitch angle P) of the current attitude of the measurement shaft 10 from the reference attitude is displayed numerically on the display unit 14 as well as graphically (guide display 40).

[0082] In the guide display 40, as the measurement shaft 10 moves in the yaw direction, the first position marker 51 is displayed to move along the yaw reference circle 41. As the measurement shaft 10 moves in the pitch direction, the second position marker 52 is displayed to move along the pitch reference line 42 on the vertical axis, and as the measurement shaft 10 moves in the roll direction, the second position marker is displayed to move along the roll reference line 43 on the horizontal axis.

[0083] Such a guide display 40 allows the operator to intuitively grasp the amount of deviation of the current posture of the measurement shaft 10 from the reference posture. Therefore, by referring to the display unit 14, the operator can perform accurate measurement while aligning the posture of the measurement shaft 10 with the reference posture.

[0084] As described above, according to the force gauge 1 of the first embodiment, even though it is a handheld force gauge, it is possible to maintain the measurement shaft 10 in a desired position and to measure load easily and appropriately.

[0085] 8, the control unit 13 is configured to determine the reference posture based on the posture of the measurement shaft 10 that is taught before the load is measured. Therefore, the reference posture can be appropriately set depending on the measurement target.

[0086] In particular, the housing 5 of the force gauge 1 has multiple reference surfaces (side surface 21a, rear surface 23, etc.) that are perpendicular to each other, so that the orientation of the measurement shaft 10 can be suitably taught by bringing these reference surfaces into contact with the surface of the measurement object (top surface 7a and side surface 7b of the main body 7). Therefore, the reference orientation of the measurement shaft 10 can be easily and appropriately set by utilizing the reference surfaces of the housing 5.

[0087] In addition, in this embodiment 1, a correction value corresponding to the load when the attitude of the measurement shaft 10 is the reference attitude is determined based on the deviation amount of the attitude of the measurement shaft 10 from the reference attitude (yaw angle Y, roll angle R, and pitch angle P) and the measured value of the load.

[0088] Therefore, for example, if the desired posture of the measurement shaft 10 during measurement is set as the reference posture, even if the posture of the measurement shaft 10 during measurement deviates from the desired posture, the load that would be applied if the measurement shaft 10 were in the desired posture can be obtained as a correction value. Second Embodiment

[0089] Next, a second embodiment will be described with reference to Fig. 15 and Fig. 16. Fig. 15 is an explanatory diagram showing an example of measuring the load when pulling out the drawer portion 8 in an oblique direction. Fig. 16 is a flowchart showing a measurement method in the second embodiment. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0090] In the above-described first embodiment, an example was described in which the posture along the sliding direction S of the drawer section 8 is set as the reference posture of the measurement shaft 10, and the housing 5 is moved so that the current posture of the measurement shaft 10 coincides with the reference posture, and load measurement is performed by moving the housing 5 so that the current posture of the measurement shaft 10 coincides with the reference posture. In contrast to this, in the second embodiment, load measurement is performed by setting a posture different from the reference posture as the desired posture of the measurement shaft 10.

[0091] First, as shown in Fig. 16, steps S11 to S14 are performed similarly to steps S1 to S4 in the above-described embodiment 1. That is, in step S11, the control unit 13 switches the display mode in response to the selection of the operator, and displays the yaw reference circle 41, pitch reference line 42, and roll reference line 43 on the display unit 14, as shown in Fig. 9.

[0092] Next, in step S12, the reference posture of the measurement shaft 10 is determined. That is, the control unit 13 sets the reference posture of the measurement shaft 10 based on the posture of the measurement shaft 10 taught by the operator. As shown in FIG. 15, the reference posture is a posture along the sliding direction S of the drawer unit 8. When the measurement shaft 10 is in the reference posture, the posture of the housing 5 becomes the posture indicated by the symbol M.

[0093] Subsequently, in step S13, the control unit 13 determines the deviation amount (yaw angle Y, pitch angle P, and roll angle R) of the current attitude of the measurement shaft 10 from the reference attitude based on the output of the inertial sensor 12. Next, in step S14, the determined deviation amount of the attitude of the measurement shaft 10 is displayed numerically on the display unit 14, and is also displayed graphically including the guide display 40.

[0094] Next, in step S15, the operator determines a desired measurement posture of the measurement shaft 10 that is different from the reference posture. As shown in Fig. 15, the desired measurement posture of the measurement shaft 10 can be, for example, a posture in which the yaw angle Y is shifted by a predetermined amount (for example, 30°) from the reference posture. When the measurement shaft 10 is in the measurement posture, the posture of the housing 5 becomes the posture indicated by the symbol N.

[0095] Then, the operator moves the housing 5 so that the posture of the measurement shaft 10 matches the desired measurement posture (i.e., the housing 5 is in posture N) while referring to the deviation of the posture of the measurement shaft 10 from the reference posture displayed on the display unit 14. In this way, the load acting on the measurement shaft 10 is measured.

[0096] Subsequently, in step S16, the display unit 14 displays the load measurement values 26, 27, and 28. Thereafter, the control unit 13 returns to step S13 and repeats the processes from step S13 to step S16 to determine the load measurement values in real time and display them on the display unit 14.

[0097] Therefore, in the second embodiment, as in the first embodiment, the guide display 40 is displayed on the display unit, so that the operator can intuitively grasp the amount of deviation of the current posture of the measurement shaft 10 from the reference posture. Therefore, by referring to the display unit 14, the operator can measure the desired load while maintaining the posture of the measurement shaft 10 at a desired measurement posture different from the reference posture. For example, when applying a force in a specific direction different from the sliding direction S to move the drawer section 8, it becomes possible to accurately measure the load required for that purpose.

[0098] In this way, even with the force gauge 1 of the second embodiment, which is a handheld force gauge, it is possible to maintain the measurement shaft 10 in a desired position and to easily and appropriately measure load. Third Embodiment

[0099] Fig. 17 is an explanatory diagram showing a method for determining the reference attitude in the present embodiment 3. In the above-described embodiment 1, an example was described in which the attitude of the measurement shaft 10 was taught twice to determine the reference attitude in step S2 in the flowchart in Fig. 14. In contrast to this, in the present embodiment 3, an example will be described in which the reference attitude is determined by teaching the attitude once.

[0100] 17, in the third embodiment, a jig 60 is used to determine the reference posture. The jig 60 has a bottom plate portion 61 and a side plate portion 62 that is disposed on one side of the bottom plate portion 61 and is formed integrally with the bottom plate portion 61. The bottom plate portion 61 and the side plate portion 62 are disposed perpendicular to each other. As a result, the jig 60 has an L-shaped cross section.

[0101] As shown in Figure 17, the operator places the jig 60 on the upper surface 7a of the main body 7, abuts the bottom plate portion 61 of the jig 60 against the upper surface 7a, and positions the side plate portion 62 of the jig 60 so that it is parallel to the side surface portion 7b of the main body 7.

[0102] Next, the force gauge 1 is placed on the jig 60. At this time, the force gauge 1 is placed so that the rear surface 23 of the housing 5 abuts against the bottom plate 61 of the jig 60 and the side surface 21a of the housing 5 abuts against the side plate 62 of the jig 60. In this state, the attitude of the measurement shaft 10 is taught to the force gauge 1.

[0103] At this time, the axis of the measurement shaft 10 becomes parallel to the upper surface 7a of the main body 7, so the pitch angle P of the measurement shaft 10 coincides with the pitch angle Pr of the reference posture. Furthermore, the axis of the measurement shaft 10 becomes parallel to the side surface 7b of the main body 7, so the yaw angle Y of the measurement shaft 10 coincides with the yaw angle Yr of the reference posture. Therefore, according to the third embodiment, the pitch angle Pr of the reference posture (Pr = 0°) and the yaw angle Yr of the reference posture (Yr = 0°) can be set by this one posture teaching.

[0104] In the first to third embodiments, the pitch angle Pr, yaw angle Yr, and roll angle Rr are determined in advance as the reference attitude of the measurement shaft 10. However, the present invention is not limited to this. For example, it is possible to set only the pitch angle Pr and yaw angle Yr of the reference attitude without setting the roll angle Rr of the reference attitude. Therefore, the yaw angle Y and pitch angle P of the current measurement shaft 10 relative to the reference attitude may be used as the deviation amount of the attitude of the measurement shaft 10.

[0105] 14, the shape and arrangement of the display elements can be changed as appropriate without departing from the spirit of the present invention. In addition, in the above-described first to third embodiments, an example of measuring the load when moving the drawer unit 8 in the sliding direction S has been described, but the force gauge 1 is not limited to such measurement applications and can be widely used for various other measurements. [Industrial Applicability]

[0106] As described above, the present invention is useful for a handheld force gauge for measuring a load and a method for measuring a load using the same. [Explanation of symbols]

[0107] 1 force gauge 5. Cabinet 7 Main Unit 8 Drawer section 10 Measuring shaft 11 Load Cell 12 Inertial Sensor 13 Control Unit 14 Display section 21a, 21b Side part (reference surface) 22 Bottom part (reference surface) 23 Back section (reference surface) 40 Guide Display 41 Yaw Reference Circle 42 Pitch Reference Line 43 Roll Reference Line 45 First position marker 46 Second position marker

Claims

1. A handheld force gauge, The housing and a measurement shaft provided so as to be capable of advancing and retreating in an axial direction while protruding from the housing; a load cell disposed inside the housing and to which a load is applied via the measurement shaft; an inertial sensor fixed to the housing; a control unit configured to determine a measured value of a load applied to the measurement shaft based on an output of the load cell, and to determine an amount of deviation of an attitude of the measurement shaft from a predetermined reference attitude based on an output of the inertial sensor; a display unit that displays the amount of deviation of the posture of the measurement shaft determined by the control unit;

2. 2. The force gauge according to claim 1, wherein the control unit is configured to determine the reference attitude based on an attitude of the measurement shaft that is taught before the load is measured and detected by the inertial sensor.

3. the housing has a plurality of reference surfaces that are perpendicular to each other; The force gauge according to claim 2 , wherein the plurality of reference surfaces are configured to be able to come into contact with a surface of the measurement object when teaching the attitude of the measurement shaft.

4. 2. The force gauge according to claim 1, wherein the control unit is configured to determine a correction value corresponding to the load when the attitude of the measurement shaft is the reference attitude, based on an amount of deviation of the attitude of the measurement shaft from the reference attitude and the measured value of the load.

5. The display unit a yaw reference circle indicating a deviation amount in a yaw direction of the measurement shaft relative to the reference attitude; a pitch reference line which is a vertical axis extending in a diameter direction of the yaw reference circle and indicates a deviation amount in a pitch direction of the measurement shaft from the reference attitude; a first position marker that is movable along the yaw reference circle and indicates a current position of the measurement shaft in a yaw direction; 2. The force gauge according to claim 1, further comprising: a second position marker that is movable relative to the pitch reference line and indicates a current position of the measurement shaft in the pitch direction.

6. the display unit displays a roll reference line, which is a horizontal axis extending in a diameter direction of the yaw reference circle and indicates a deviation amount of the measurement shaft in a roll direction from the reference attitude, 6. The force gauge according to claim 5, wherein the second position marker is movable relative to the pitch reference line and the roll reference line, and simultaneously indicates a current position of the measurement shaft in the pitch direction and a current position of the measurement shaft in the roll direction.

7. A method for measuring a load using a handheld force gauge, comprising: The force gauge includes a housing in which an inertial sensor is fixed, a measurement shaft that protrudes from the housing and is movable back and forth in an axial direction, and a control unit and a display unit that are provided in the housing, an operator instructing the attitude of the measurement shaft to the force gauge, and the control unit determining a reference attitude based on an output of the inertial sensor; determining, by the control unit, an amount of deviation of the attitude of the measurement shaft from the reference attitude based on an output of the inertial sensor; a step in which a display unit displays the deviation amount of the attitude of the measurement shaft determined by the control unit; and measuring the load acting on the measurement shaft by the operator moving the housing so as to maintain the attitude of the measurement shaft consistent with the reference attitude while referring to the deviation of the attitude of the measurement shaft from the reference attitude displayed on the display unit.

8. A method for measuring a load using a handheld force gauge, comprising: The force gauge includes a housing in which an inertial sensor is fixed, a measurement shaft that protrudes from the housing and is movable back and forth in an axial direction, and a control unit and a display unit that are provided in the housing, an operator instructing the attitude of the measurement shaft to the force gauge, and the control unit determining a reference attitude based on an output of the inertial sensor; determining, by the control unit, an amount of deviation of the attitude of the measurement shaft from the reference attitude based on an output of the inertial sensor; a step in which a display unit displays the deviation amount of the attitude of the measurement shaft determined by the control unit; and measuring the load acting on the measurement shaft by the operator moving the housing so as to maintain the attitude of the measurement shaft consistent with a desired measurement attitude that is different from the reference attitude, while referring to the deviation of the attitude of the measurement shaft from the reference attitude displayed on the display unit.

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