Striking force measurement system

Abstract

To more accurately measure the striking force of hammers and other striking tools. [Solution] The sensor unit 11 is fixed to the medical hammer 1 by inserting the handle 1A of the medical hammer 1 between the recesses of the right block 112 and the left block 113, and fastening the right block 112 and the left block 113 with connecting screws 114 (a, b). The two acceleration sensors 111 positioned on the right block 112 and the left block 113 are symmetrical with respect to the axis of the handle of the medical hammer 1 when the sensor unit 11 is fixed to the medical hammer 1 (d). The acceleration associated with striking with the medical hammer 1 is detected from the average of the two acceleration sensors 111.

Description

Technical Field

[0001] The present invention relates to a technique for measuring a striking force, which is a force generated by striking with a striking tool such as a hammer.

Background Art

[0002] As a technique for measuring a striking force, which is a force generated by striking with a striking tool such as a hammer, a technique is known in which an acceleration sensor is fixed to the head of a hammer and the striking force is measured from the acceleration generated when the hammer strikes (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the technique of measuring the striking force using the acceleration sensor fixed to the head of the hammer described above, there was a case where the acceleration generated when the hammer strikes was too large and appropriate measurement could not be performed. In addition, depending on the position of the striking point on the head of the hammer, there was a variation in the acceleration generated in the acceleration sensor, which sometimes hindered appropriate measurement. Therefore, an object of the present invention is to more appropriately measure the striking force of a striking tool such as a hammer.

Means for Solving the Problems

[0005] To achieve the above objectives, the present invention provides a striking force measuring system for measuring the striking force, which is the force applied when striking an object with a striking tool comprising a head for striking an object and a handle connected to the head and held by the user to operate the head. The system includes a sensor unit that can be fixed to the handle of the striking tool and a measuring device. An acceleration sensor is fixed to the sensor unit, and the measuring device measures a value representing the striking force generated when the striking tool strikes an object, based on the output of the acceleration sensor.

[0006] In this way, by fixing a sensor unit with an acceleration sensor to the handle and detecting acceleration, it is possible to detect the attenuated acceleration generated at the head of the striking tool at a position away from the head, and even when the acceleration generated at the head is large, the acceleration can be detected appropriately.

[0007] Furthermore, the amount of attenuation of the detected acceleration from the acceleration generated at the head, and the accuracy of detecting the acceleration generated at the head, can be adjusted by changing the distance from the head of the striking tool to the position where the sensor unit is fixed to the handle. In other words, the greater the distance from the head of the striking tool to the position where the sensor unit is fixed to the handle, the greater the attenuation of the acceleration detected by the acceleration sensor from the acceleration generated at the head, and consequently, the lower the accuracy of the acceleration generated at the head that can be detected by the acceleration sensor. Therefore, for example, by adjusting the position where the sensor unit is fixed to the handle, the detection accuracy can be optimized while keeping the magnitude of the acceleration acting on the acceleration sensor within the detectable range.

[0008] In this striking force measurement system, two acceleration sensors may be fixed to the sensor unit, and when the sensor unit is fixed to the handle of the striking tool, the two acceleration sensors may be positioned symmetrically with respect to the axis of the handle of the striking tool and detect acceleration in the same direction. In this case, the measuring device measures a value representing the striking force generated when the striking tool strikes an object, from the average of the accelerations represented by the two acceleration sensors.

[0009] By calculating the average in this way, since the two acceleration sensors are positioned symmetrically with respect to the axis of the handle of the striking tool, the same average acceleration can be detected regardless of the position of the striking point between the head and the object. Based on this average, accurate measurements can be taken regardless of the position of the striking point.

[0010] In this striking force measurement system, the two acceleration sensors may be configured to detect the acceleration in the direction normal to the striking surface at the head of the striking tool, while the sensor unit is fixed to the handle of the striking tool. Alternatively, with the sensor unit fixed to the handle of the striking tool, the two acceleration sensors may be configured to detect axial acceleration in the handle of the striking tool. Furthermore, the above-described striking force measurement system may include a first block and a second block in the sensor unit, and the sensor unit may be fixed to the handle of the striking tool by fastening the first block and the second block together with the handle of the striking tool sandwiched between them.

[0011] In the above-described striking force measurement system, the striking tool is, for example, a medical hammer. [Effects of the Invention]

[0012] As described above, according to the present invention, the striking force of a hammer or other striking tool can be measured more accurately. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows the configuration of a striking force measurement system according to an embodiment of the present invention. [Figure 2] This figure shows a sensor unit according to an embodiment of the present invention. [Figure 3] This figure shows the attachment of a sensor unit according to an embodiment of the present invention to a hammer. [Figure 4] This figure shows the configuration of a measuring device according to an embodiment of the present invention. [Figure 5] It is a diagram showing a processing example of a measuring device according to an embodiment of the present invention. [Figure 6] It is a diagram showing the significance of the processing of the measuring device according to an embodiment of the present invention. [Figure 7] It is a diagram showing a display example of a display unit according to an embodiment of the present invention. [Figure 8] It is a diagram showing another configuration example of a percussion force measurement system according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the present invention will be described by taking an application to a medical hammer as an example. FIG. 1 shows the configuration of a percussion force measurement system according to the present embodiment. As shown in the figure, the percussion force presentation system according to the present embodiment includes a sensor unit 11 fixed to a medical hammer 1, a measurement device 12, a display unit 13, and a speaker unit 14. The sensor unit 11 includes an acceleration sensor 111 that detects the acceleration generated in the medical hammer 1 when the object of the medical hammer 1 is struck. The measurement device 12 is wired-connected to the acceleration sensor 111 of the sensor unit 11, measures the percussion force generated when the object of the medical hammer 1 is struck from the output of the sensor of the sensor unit 11, and causes the display unit 13 connected by wire or wirelessly to emit light in a color corresponding to the measured percussion force, or outputs a sound with a pitch (tone height) corresponding to the measured percussion force from the speaker unit 14 connected by wire or wirelessly. However, the measurement device 12 and the acceleration sensor 111 may be connected by wireless connection instead of wired connection.

[0015] FIG. 2 shows the sensor unit 11. FIG. 2a shows the upper surface of the sensor unit 11, FIG. 2b shows the front surface of the sensor unit 11, and FIG. 2c shows the right side surface of the sensor unit 11. Further, FIG. 2d shows the appearance of the sensor unit 11 in perspective. Note that the rear surface of the sensor unit 11 appears the same as the front surface, and the left side surface of the sensor unit 11 appears the same as the right side surface.

[0016] As shown in the figure, the sensor unit 11 has a structure in which a right block 112 and a left block 113 are connected back and forth by two connecting screws 114. Here, it is preferable that the materials of the right block 112 and the left block 113 are the same as those of the medical hammer 1. Also, as shown in the figure, acceleration sensors 111 are respectively fixed to the front surface of the right block 112 and the rear surface of the left block 113 of the sensor unit 11. In addition, a tapered recess recessed to the right is provided on the left side surface of the right block 112, and a tapered recess recessed to the left is provided on the right side surface of the left block 113. Then, as shown in FIG. 3b, the handle 1A of the medical hammer 1 shown in FIG. 3a is sandwiched between the recesses of the right block 112 and the left block 113, and the right block 112 and the left block 113 are fastened with the connecting screw 114, whereby the sensor unit 11 is fixed to the medical hammer 1 as shown in FIG. 3c. Note that FIG. 3b shows the relationship between the handle 1A and the sensor unit 11 as viewed in the axial direction of the handle 1A of the medical hammer 1.

[0017] Now, the sensor unit 11 can be fixed to the medical unit so that the right side surface and the left side surface are parallel to the normal line of the striking surface at the head of the medical hammer 1. In the fixed state like this, one acceleration sensor 211 is located on the first striking surface side at the head of the medical hammer 1, and the other acceleration sensor 211 is located on the second striking surface side, which is the striking surface opposite to the first striking surface at the head of the medical hammer 1.

[0018] Here, the two acceleration sensors 111 are fixed to the right block 112 and the left block 113 so as to be symmetric with respect to the axis of the handle of the medical hammer 1 in a state where the sensor unit 11 is fixed to the medical hammer 1. In this case, the two acceleration sensors 111 detect accelerations in the same normal direction to the striking surface at the head of the medical hammer 1, as indicated by the arrows in Figure 3d, with the sensor unit 11 fixed to the medical hammer 1. Figure 3d shows the medical hammer 1 as viewed from the opposite side of the head, along the axial direction of the handle.

[0019] In this way, by fixing the sensor unit 11 to the handle and detecting acceleration, it is possible to detect the attenuated acceleration generated at the head of the medical hammer 1 at a position away from the head, and even when the acceleration generated at the head is large, the acceleration can be detected appropriately. Furthermore, the amount of attenuation of the acceleration detected from the acceleration generated at the head, and the accuracy of detecting the acceleration generated at the head, can be adjusted by changing the distance from the head of the medical hammer 1 to the position where the sensor unit 11 is fixed to the handle. In other words, the greater the distance from the head of the medical hammer 1 to the position where the sensor unit 11 is fixed to the handle, the greater the attenuation of the acceleration detected by the acceleration sensor 111 from the acceleration generated at the head, and consequently, the lower the accuracy of the acceleration generated at the head that can be detected by the acceleration sensor 111. Therefore, for example, by adjusting the position where the sensor unit 11 is fixed to the handle, the detection accuracy can be optimized while keeping the magnitude of the acceleration acting on the acceleration sensor 111 within a detectable range.

[0020] Next, Figure 4 shows the configuration of the measuring device 12. As shown in the figure, the measuring device 12 includes two pre-processing units 121 corresponding to each of the two acceleration sensors 111, an averaging unit 122, an acceleration level calculation unit 123, a display controller 124, a speaker controller 125, and a mode control unit 126. The two pre-processing units 121 perform filtering on the output of the corresponding acceleration sensor 111 to remove unwanted frequency components. Furthermore, the two preprocessing units 121 perform half-wave rectification and other processes on the filtered output of the acceleration sensor 111. That is, if the signal waveform of the filtered output of the acceleration sensor 111 is as shown in Figure 5a1, it is converted into a signal waveform in which only the positive component is extracted, as shown in Figure 5a2. By performing this half-wave rectification process, only the positive striking force, excluding the reaction force, can be extracted.

[0021] The execution of this half-wave rectification process is controlled by the mode control unit 126. The averaging unit 122 calculates the average of the outputs of the two preprocessing units 121. In other words, if the first signal waveform, which is the output of the first preprocessing unit 121, is shown in Figure 5b1, and the second signal waveform, which is the output of the second preprocessing unit 121, is shown in Figure 5b2, then the average of the first signal waveform and the second signal waveform is calculated as shown in Figure 5b3. By calculating the average in this way, since the two acceleration sensors 111 are positioned symmetrically with respect to the axis of the handle of the medical hammer 1, it is possible to detect accelerations with similar absolute values ​​as the average value whether P1, as shown in Figure 6, is the point of impact with the object, or whether P2 is the point of impact with the object.

[0022] Furthermore, if the orientation of the acceleration detection axes of the two acceleration sensors 111 is set so that the directions of acceleration detected by the two acceleration sensors 111 are in opposite directions when the medical hammer 1 strikes, the sign of one of the signal waveforms, either the first or the second, is reversed and the average is calculated in order to align the signs of the signal waveforms.

[0023] Next, the acceleration level calculation unit 123 applies an LPF with a predetermined time constant to the signal waveform output by the averaging unit 122, after folding the negative portion to a positive value. In other words, if the signal waveform output by the averaging unit 122 is as shown in Figure 5c1, then, as shown in Figure 5c2, the negative portion of the signal waveform in Figure 5c1 is folded back to a positive value, and then an LPF (Low Pass Filter) is applied to obtain the signal waveform in Figure 5c3. Then, the acceleration level calculation unit 123 determines the peak value and RMS value of the signal waveform to which the LPF has been applied as the striking force, in accordance with the control of the mode control unit 126. Here, since the range of the striking force to be measured and presented is wide, the striking force is determined as a decibel value using a predetermined 0 dB reference value.

[0024] Here, since the striking force of the medical hammer 1 is proportional to the acceleration generated during striking, the peak value and effective value obtained in this way represent the striking force of the medical hammer 1. The mode control unit 126 controls whether or not to perform half-wave rectification processing in the preprocessing unit 121, and the target (peak value or RMS value) to be determined as the striking force in the acceleration level calculation unit 123, according to the operator's settings. Then, the display controller 124 controls the light emission color of the display unit 13 in accordance with the striking force calculated by the acceleration level calculation unit 123, similar to the first embodiment, and the speaker controller 125 controls the output sound of the speaker unit 14 in accordance with the striking force calculated by the acceleration level calculation unit 123.

[0025] In other words, the display controller 124, via the mode control unit 126, causes the display unit 13 to illuminate for a predetermined period (for example, 0.5 seconds) in a color corresponding to the striking force detected by the striking force detection unit. The speaker controller 125, via the mode control unit 126, causes the speaker unit 14 to output a sound with a pitch (sound level) corresponding to the striking force detected by the striking force detection unit for a predetermined period (for example, 0.5 seconds). As shown in Figure 7a, the display unit 13 is equipped with a multi-color light-emitting section 131 made of LEDs or the like, and the light-emitting section 131 emits light in colors according to the control of the display controller 124 of the measurement unit. The display controller 124 changes the color of this light emission according to the decibels calculated by the acceleration level calculation unit 123. The decibels calculated by the acceleration level calculation unit 123 and the emission color are pre-associated by the mode control unit 126 as follows: In other words, the mode control unit 126 receives the setting of the lower limit Min and upper limit Max of the decibel presentation range from the operator, and as shown in Figure 7b1, it associates decibels with the emitted color such that as the decibels increase between the lower limit Min and the upper limit Max, the hue of the emitted color corresponding to the striking force gradually changes from blue, blue-green, green, yellow, and red.

[0026] Therefore, for example, as shown in Figure 7b2, if the lower limit Min of the set decibel display range is 80 dB and the upper limit Max is 150 dB, then as the decibels increase from 80 dB to 150 dB, the hue of the light-emitting color corresponding to the decibel gradually changes from blue, blue-green, green, yellow, and red. The light-emitting part 131 of the display unit 13 illuminates with the light-emitting color corresponding to the decibel calculated by the acceleration level calculation unit 123.

[0027] However, the number of colors that can be associated with decibels may be limited to a select few. For example, as shown in Figure 7c1, the striking force and the emitted light color may be associated such that as the decibel increases between the lower limit Min and the upper limit Max, the emitted light color corresponding to the decibel changes from blue, blue-green, green, yellow, and red. In this case, for example, as shown in Figure 7c2, if the lower limit Min of the set decibel display range is 80 dB and the upper limit Max is 130 dB, then decibels between 80 dB and 90 dB are associated with blue, decibels between 90 dB and 100 dB with blue-green, decibels between 100 dB and 110 dB with green, decibels between 110 dB and 120 dB with yellow, and decibels between 120 dB and 130 dB with red. The light-emitting part 131 of the display unit 13 will then emit light in the color corresponding to the range that includes the decibels calculated by the acceleration level calculation unit 123.

[0028] Next, the speaker controller 125 changes the pitch (height of the sound) of the output sound according to the decibels calculated by the acceleration level calculation unit 123. The decibels calculated by the acceleration level calculation unit 123 and the pitch of the output sound of the speaker controller 125 are pre-associated by the mode control unit 126 as follows: In other words, the mode control unit 126 receives the lower limit Min and upper limit Max of the decibel presentation range from the operator, and associates the decibel level with the pitch of the output sound so that as the striking force increases between the lower limit Min and the upper limit Max, the pitch of the output sound changes to a higher pitch.

[0029] More specifically, for example, the range between the lower limit (Min) and upper limit (Max) of the decibel range is divided into five parts, and each range is associated with the notes Do, Re, Mi, Fa, and So, starting from the lower limit. In this case, if the set decibel range has a lower limit (Min) of 80 dB and an upper limit (Max) of 130 dB, then a striking force between 80 dB and 90 dB is associated with "Do," a decibel between 90 dB and 100 dB with "Re," a decibel between 100 dB and 110 dB with "Mi," a decibel between 110 dB and 120 dB with "Fa," and a decibel between 120 dB and 130 dB with "So." The speaker unit 14 outputs a sound with a pitch corresponding to the range that includes the decibel calculated by the acceleration level calculation unit 123.

[0030] Embodiments of the present invention have been described above. Incidentally, the arrangement of the two acceleration sensors 111 in the sensor unit 11 in this embodiment may be as shown in Figures 8a and 8b, such that when the sensor unit 11 is fixed to the medical hammer 1, one acceleration sensor 111 is on one side of the head of the medical hammer 1 and the other acceleration sensor 111 is on the other side of the head of the medical hammer 1.

[0031] However, even in this case, the two acceleration sensors 111 are positioned symmetrically with respect to the axis of the handle of the medical hammer 1, with the sensor unit 11 fixed to the medical hammer 1, on the right block 112 and the left block 113. In this case, the two acceleration sensors 111 detect acceleration in the same axial direction of the handle, as indicated by the arrows in Figure 8c, with the sensor unit 11 fixed to the medical hammer 1. In this manner, the striking force of the medical hammer 1 can be detected, and the averaging process of the averaging unit 122 allows for the detection of the same acceleration as an average value whether P1, as shown in Figure 8c, is the striking point where it collides with the object, or whether P2 is the striking point where it collides with the object.

[0032] The embodiments of the present invention have been described above. In the above, we have described an embodiment of the striking force presentation system according to the present invention using the application to a medical hammer 1 as an example. However, this embodiment can be similarly applied as a system for presenting the striking force of any striking tool used to strike an object, such as a hammer other than the medical hammer 1.

[0033] Furthermore, in the above embodiments, the measuring device 12 may be equipped with a function to record the decibels calculated by the acceleration level calculation unit 123 or to output them externally. Alternatively, the display unit 13 may display the decibels calculated by the acceleration level calculation unit 123 as a numerical value.

[0034] Furthermore, although the above embodiments describe the case where the striking force is displayed, it is also possible to display the integrated value of the striking force. That is, the integrated value of the striking force measured by the measuring device 12 can be obtained, and instead of the striking force, the obtained integrated value can be used to control the light emission color of the display unit 13 or the pitch of the sound output from the speaker unit 14, as described above. Alternatively, the measured device 12 may display the obtained integrated value as a numerical value. [Explanation of Symbols]

[0035] 1...Medical hammer, 11...Sensor unit, 12...Measurement device, 13...Display unit, 14...Speaker unit, 111...Accelerometer, 112...Right block, 113...Left block, 114...Connecting screw, 121...Pre-processing unit, 122...Averaging unit, 123...Accelerometer level calculation unit, 124...Display controller, 125...Speaker controller, 126...Mode control unit, 131...Light-emitting unit.

Claims

1. A striking force measuring system for measuring striking force, which is the force applied when striking an object with a striking tool comprising a head for striking an object and a handle connected to the head, which is held by the user to operate the head, A sensor unit that can be fixed to the handle of the aforementioned striking tool, It has a measuring device, An acceleration sensor is fixed to the aforementioned sensor unit. The aforementioned measuring device is a striking force measuring system characterized by measuring a value representing the striking force generated when the striking tool strikes an object, based on the output of the acceleration sensor.

2. A striking force measuring system according to claim 1, Two acceleration sensors are fixed to the aforementioned sensor unit. With the sensor unit fixed to the handle of the striking tool, the two acceleration sensors detect acceleration in the same direction at positions symmetrical with respect to the axis of the handle of the striking tool. The aforementioned measuring device is a striking force measuring system characterized by measuring a value representing the striking force generated when the striking tool strikes an object, based on the average of the accelerations represented by the two acceleration sensors.

3. A striking force measuring system according to claim 2, A striking force measurement system characterized in that, with the sensor unit fixed to the handle of the striking tool, the two acceleration sensors detect acceleration in the direction normal to the striking surface at the head of the striking tool.

4. A striking force measuring system according to claim 2, A striking force measurement system characterized in that, with the sensor unit fixed to the handle of the striking tool, the two acceleration sensors detect the axial acceleration in the handle of the striking tool.

5. A striking force measuring system according to claim 1 or 2, The sensor unit comprises a first block and a second block. A striking force measuring system characterized in that the sensor unit is fixed to the handle of the striking tool by fastening the first block and the second block together with the handle of the striking tool sandwiched between them.

6. A striking force measuring system according to claim 1, 2, 3, or 4, The aforementioned striking tool is a medical hammer, and is used in this striking force measurement system.

7. A striking force measuring system according to claim 5, The aforementioned striking tool is a medical hammer, and is used in this striking force measurement system.

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