Soil Hardness Measuring Instrument

Abstract

To provide a soil hardness measuring instrument that enables a user to intuitively grasp that the soil is hard. [Solution] The device comprises a holder 1 that can be held by an operator, a measuring rod 2 that protrudes below the bottom of the holder 1 so that its tip comes into contact with the soil A to be measured and is movable up and down relative to the holder 1, a biasing means 3 that is provided within the holder 1 and biases the measuring rod 2 downward so that the measuring rod 2 can be retracted from a predetermined initial position, a conversion means 4 that is provided within the holder 1 and converts the amount of retraction of the measuring rod 2 from its initial position into an electrical signal, and a warning means 5 that is provided in the holder 1 and issues a warning depending on the output of the conversion means 4.

Description

[Technical Field]

[0001] The present invention relates to a soil hardness measuring instrument for measuring soil hardness, which affects the quality of potatoes, such as their shape. [Background technology]

[0002] It is generally known that soil hardness and the location of the plow pan have a significant effect on the quality of the shape of Chinese yam and Japanese yam. In other words, if the soil at the soil layer where the roots grow is hard, the potatoes will become short and the roots will bend. For this reason, measuring soil hardness is important when identifying fields that produce high-quality potatoes. As a conventional soil hardness measuring instrument, the so-called Yamanaka type soil hardness measuring instrument is already known. One example of this type of soil hardness measuring device is a cylindrical body with a conical probe at its bottom end, which is resilient from above with a compression spring and can move up and down. A longitudinal groove is formed in the wall of the cylindrical body, and scales are provided on both sides of the groove. When the conical surface is placed in contact with the soil surface to be measured and the cylinder is pressed into the soil from above, the probe penetrates the soil. However, frictional resistance due to the hardness of the soil generates a resistance force that pushes the probe into the cylinder against the resilience of the compression spring. The upper end of the probe moves the probe housed in the groove, and the soil hardness is measured by reading the scale at the position where the probe is located.

[0003] This type of soil hardness measuring device has the drawback that, when measuring on-site, if the long groove is not facing downward, soil will get in between the measuring piece and the long groove, changing the frictional resistance when the measuring piece moves, or, because the measuring piece is simply positioned inside the long groove, the measuring piece will move if an external shock is applied, which can easily cause errors. For this reason, it is necessary to repeat the measurement to prevent errors. A soil hardness measuring instrument that overcomes such problems is known, for example, from Patent Document 1.

[0004] Patent document 1 provides a soil hardness measuring instrument that does not have any grooves in the cylindrical body, allows the indicator part to be read accurately, and aims to prevent the indicator part from moving even when the measuring probe is pulled out of the soil. Patent Document 1 discloses an embodiment in which a lower body having a lower flange is screwed onto the lower end of a cylindrical main body, an upper body having an upper flange is screwed onto the upper end of the cylindrical main body, a measuring probe biased from above by a compression spring is attached to the lower interior of the cylindrical main body so that it can move up and down, and a locking step is formed on the upper outer periphery of the measuring probe to engage with the upper end of the lower body, a connecting rod made of a magnetic material is inserted into a through hole provided in the center of the upper body so that it can move up and down, an indicator part with a scale is fixed to the upper end of the connecting rod and is arranged so that it can move up and down from above the upper body, the lower part of the connecting rod is inserted into a blind hole provided above the measuring probe, the connecting rod is inserted into a communicating hole that communicates with the through hole in the upper body, and is arranged so that it can move up and down in contact with a magnet piece fixed inside the upper body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Publication No. 5-45962 (Example, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In the soil hardness measuring instrument described in Patent Document 1, it may be possible to achieve the objective of not providing any grooves in the cylindrical body, allowing the indicator part to be read accurately, and preventing the indicator part from moving even when the measuring probe is pulled out of the soil. However, since the operator must read the indicator, it is difficult to avoid operator errors in reading the indicator. Furthermore, when measuring soil hardness again, the operator can manually push the indicator protruding from the upper body into the inner cylinder body and insert it into the blind hole in the cylinder body until the locking piece engages with the top of the measuring probe. However, if the preparation for measurement is incomplete, it may be difficult to measure soil hardness accurately.

[0007] The technical problem that this invention aims to solve is to provide a soil hardness measuring instrument that allows users to intuitively grasp whether the soil is hard. [Means for solving the problem]

[0008] The present invention is a soil hardness measuring instrument comprising: a holder that can be held by an operator; a measuring rod that protrudes below the bottom of the holder so that its tip comes into contact with the soil to be measured and is movable up and down relative to the holder; a biasing means provided within the holder that biases the measuring rod downward so that it can be retracted from a predetermined initial position; a conversion means provided within the holder that converts the signal into an electrical signal depending on the amount the measuring rod is retracted from its initial position; and a warning means provided in the holder that issues a warning in accordance with the output of the conversion means. [Effects of the Invention]

[0009] According to the present invention, a soil hardness measuring instrument can be provided that allows users to intuitively grasp whether the soil is hard. [Brief explanation of the drawings]

[0010] [Figure 1] 1A is an explanatory diagram showing an outline of an embodiment of a soil hardness measuring instrument according to the present invention, and FIG. 1B is an explanatory diagram showing the operation of the soil hardness measuring instrument shown in FIG. 1A. [Figure 2] 1 is an external perspective view of a soil hardness measuring instrument according to a first embodiment. FIG. [Figure 3] 1 is an explanatory cross-sectional view showing the inside of a holder of a soil hardness measuring instrument according to a first embodiment. FIG. [Figure 4] 1A is an explanatory diagram showing the holder structure used in the first embodiment and the components mounted on the door side of the holder, and FIG. 1B is a view seen from the direction of the arrow B in FIG. 1A. [Figure 5]FIG. 2(a) is an explanatory diagram showing an assembled state of the measuring rod unit used in the first embodiment, and FIG. 2(b) is an explanatory diagram showing a state in which the main parts of the measuring rod unit are disassembled. [Figure 6] FIG. 1(a) is an explanatory diagram showing a schematic diagram of an initial setting operation of a soil hardness measuring instrument according to a first embodiment, and FIG. 1(b) is an explanatory diagram showing the contents of the initial setting operation of the soil hardness measuring instrument shown in 1(a). [Figure 7] (a) is a graph showing the relationship between the retraction amount of the measuring rod and the resistance value of the variable resistor, (b) is a graph showing the relationship between the resistance value of the variable resistor and the frequency of the oscillator board (variable oscillator), and (c) is an explanatory diagram showing the relationship between the frequency of the oscillator board (variable oscillator) and the acoustics of the speaker sound. [Figure 8] 1(a) and (b) are explanatory diagrams showing the soil hardness measurement work for the measurement soils A1 and A2, and FIG. 1(c) is an explanatory diagram showing the measurement results of the soil hardness of the measurement soils A1 and A2. [Figure 9] 1A is an explanatory diagram showing the main parts of a soil hardness measuring instrument according to a first modified embodiment, and FIG. 1B is an explanatory diagram showing the results of measuring soil hardness using the soil hardness measuring instrument shown in FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0011] Overview of the implementation form FIG. 1(a) is an explanatory diagram showing an outline of an embodiment of a soil hardness measuring instrument to which the present invention is applied. In the same figure, the soil hardness measuring instrument D comprises a holder 1 that can be held by an operator, a measuring rod 2 that protrudes below the bottom of the holder 1 so that its tip comes into contact with the soil A to be measured and is movable up and down relative to the holder 1, a biasing means 3 that is provided within the holder 1 and biases the measuring rod 2 downward so that the measuring rod 2 can be retracted from a predetermined initial position, a conversion means 4 that is provided within the holder 1 and converts the signal into an electrical signal that depends on the amount the measuring rod 2 is retracted from its initial position, and a warning means 5 that is provided in the holder 1 and issues a warning depending on the output of the conversion means 4. In FIG. 1( a ), reference numeral 9 denotes a power supply that supplies power to the conversion means 4 and the warning means 5 .

[0012] In such technical means, the holder 1 has a structure that can be held by an operator, and as long as it is equipped with a measuring rod 2, a biasing means 3, a conversion means 4, and a warning means 5, the shape may be selected appropriately, such as a box-like or cylindrical shape. The measuring rod 2 is held in the holder 1 so that it can move up and down, and is positioned so that it protrudes from the bottom of the holder 1. The tip of the measuring rod 2 is preferably configured as a cone from the viewpoint of stabilizing contact with the soil A. The tip of the cone is preferably curved from the viewpoint of safety. In addition, in Figure 1(a), the symbol 7 is a guide member that is attached to a through hole at the bottom of the holder 1 and guides the measuring rod 2 so that it can move up and down. In this example, the initial position of the measuring rod 2 is set to a predetermined position. At this time, the measuring rod 2 is held in the initial position while receiving the biasing force from the biasing means 3. For example, a part of the measuring rod 2 may be blocked by a stopper means (not shown) to restrict the position of the measuring rod 2 so that it does not move in the protruding direction beyond the initial position.

[0013] Furthermore, for example, a compressed coil spring or the like is used as the biasing means 3. The biasing force of the biasing means 3 applied to the measuring rod 2 located at the initial position may be uniquely selected, but from the viewpoint of selecting a biasing force suitable for the soil hardness to be measured, it is preferable to make it adjustable. The conversion means 4 may be any means that converts into an electric signal depending on the amount of retraction (mechanical displacement) from the initial position of the measuring rod 2. In this case, the electric signal may be selected appropriately from AC frequency, pulse width, DC current value, voltage, etc. The warning means 5 may be appropriately selected as long as it issues a warning (sound, color, light, vibration, etc.) that stimulates the auditory, visual, or tactile senses.

[0014] When using the soil hardness measuring instrument D of this example, it is first necessary to appropriately select the biasing force of the biasing means 3. In this case, the biasing force of the biasing means 3 should be selected so that the measuring rod 2 retracts within the measurable range of the hardness of the soil A to be measured. In this state, as shown in Figure 1(a), when the tip of the measuring rod 2 is pressed against the surface of the soil A to be measured, the measuring rod 2 retracts against the biasing force of the biasing means 3 according to the hardness of the soil A. At this time, if the hardness of the soil A is appropriate, the measuring rod 2 will properly penetrate into the soil A, and the retraction amount d of the measuring rod 2 will be small. In contrast, if the hardness of the soil A is harder than the appropriate value (if a plow pan or the like is present), the measuring rod 2 will penetrate into the soil A, then hit a hard soil layer such as a plow pan, and retract significantly.

[0015] The retraction amount d of the measuring rod 2 is converted into a predetermined electric signal by the conversion means 4 as shown in FIG. 1(b). Then, the warning means 5 issues a warning in accordance with the output of the conversion means 4. At this time, the warning may be issued over almost the entire range of the output possible range of the conversion means 4, or may be issued when the range in which a warning is required is reached. Moreover, the warning may be changed continuously or discontinuously. In this way, the operator of the soil hardness measuring instrument D receives the warning from the warning means 5 and can intuitively grasp the hardness of the soil A that is the measurement target.

[0016] Next, a representative or preferred embodiment of the soil hardness measuring instrument D according to this embodiment will be described. First, a typical embodiment of the soil hardness measuring instrument D is one in which the conversion means 4 has variable resistance means 4a whose resistance value changes depending on the retraction amount d of the measuring rod 2 from its initial position, and the warning means 5 issues a warning that changes according to the resistance value of the variable resistance means 4a. In this example, the retraction amount d of the measuring rod 2 is associated with a change in the resistance value, thereby converting it into an electrical signal that depends on the resistance value and issuing a warning that stimulates the senses.

[0017] Furthermore, a preferred embodiment of the soil hardness measuring instrument D having a variable resistance means 4a as the conversion means 4 is one in which the conversion means 4 has an oscillation means (not shown) that converts the resistance value of the variable resistance means 4a when it changes into an electrical signal of a frequency corresponding to the resistance value, and the warning means 5 has an acoustic means that changes the sound used as a warning in accordance with the electrical signal from the oscillation means. According to this example, the hardness of the soil can be more easily determined from the change in sound than when no acoustic means is used. As a preferred embodiment of the biasing means 3, as shown in Fig. 1(a), the holder 1 is provided with an adjustment means 6 that enables adjustment of the biasing force of the biasing means 3 on the measuring rod 2. In Fig. 1(a), reference numeral 8 denotes a fixture that fixes the amount of adjustment by the adjustment means 6. According to this example, it is possible to easily select an urging force suitable for the soil hardness to be measured, compared to when the urging force of the urging means 3 is uniquely selected.

[0018] Furthermore, a representative embodiment of the holder 1 is one having a hollow holder body 1a with one side open and a door 1b that opens and closes the opening of the holder body 1a, as shown in Figure 1(a), and all or part of the warning means 5 and conversion means 4 are mounted on the door 1b side. According to this example, maintenance of the warning means 5 and the conversion means 4 can be made easier than when the warning means 5 and the conversion means 4 are all mounted on the holder main body 1a side. Furthermore, a preferred embodiment of the measuring rod 2 and the biasing means 3 is one in which the measuring rod 2 and the biasing means 3 are assembled as a single assembly unit that can be disassembled. According to this example, the soil hardness measuring instrument D can be more easily carried than when the assembled unit consisting of the measuring rod 2 and the biasing means 3 is not disassembled.

[0019] The present invention will be described in more detail below with reference to the embodiments shown in the accompanying drawings. Embodiment 1 FIG. 2 is an explanatory diagram showing the appearance of the soil hardness measuring instrument D according to the first embodiment. In the figure, the soil hardness measuring instrument D includes a holder 10 that can be held by an operator, and a measuring rod 20 that is provided so as to be movable up and down relative to the holder 10. -Holder- In this example, the holder 10 has a hollow, roughly rectangular parallelepiped holder body 11 with one side open. Gripping arms 17 are provided on the outside of both side walls 11d (see FIG. 3) that sandwich the opening of the holder body 11. The gripping arms 17 are made of cylindrical rods that protrude outward from both side walls 11d, and are gripped by an operator when holding the holder 10. The holder body 11 is also provided with a door 12 that opens and closes the opening. In this example, the holder body 11 and the door 12 are made of metal, such as aluminum or SUS, or synthetic resin. As shown in Figures 2 and 4(a) and 4(b), the door 12 is supported at the lower edge of the opening 11a of the holder body 11 via a hinge 13 so as to be openable and closable, and is lockable at the upper edge of the opening 11a via a locking metal fitting 14. The opening and closing structure of the door 12 is not limited to this, and may be selected as appropriate.

[0020] -Measuring rod- 2 and 3, the measuring rod 20 is composed of a rod body 21 made of a metal such as aluminum or SUS, and having a circular cross section. The tip of the rod body 21 is formed as a conical portion 22 having a substantially conical shape to ensure ease of insertion into the soil A. However, since it would be dangerous if the tip of the conical portion 22 were sharp, it is formed as a rounded curved portion 22a. The measuring rod 20 is provided so as to penetrate substantially the center of the bottom wall 11b of the holder main body 11. Specifically, a through hole 15 is formed substantially in the center of the bottom wall 11b of the holder main body 11, and a guide bush 16 serving as a guide member is attached to this through hole 15, and the measuring rod 20 is provided so as to be movable up and down by the guide bush 16.

[0021] - Spring parts - Furthermore, inside the holder body 11, a biasing spring part 30 is provided as a biasing means above the measuring rod 20. This biasing spring part 30 is composed of a biasing spring 31 that compresses and deforms in the vertical direction, and a pair of pressing plates 32 (specifically, 32u, 32d) that sandwich this biasing spring 31 from above and below. In this example, the lower pressure plate 32d is positioned at a predetermined initial position by a stopper 35 that restricts downward movement, as shown in Figure 6(b), and can be retracted in accordance with the upward retraction amount d of the measuring rod 20. The upper pressure plate 32u is movable up and down, and by adjusting the position of the pressure plate 32u, the relative distance between the upper and lower pressure plates 32 changes, making it possible to adjust the amount of compressive deformation of the biasing spring 31.

[0022] -Assembly unit (measuring rod and bias spring parts)- In this example, the measuring rod 20 is configured as a single assembly unit 40 that can be disassembled from the biasing spring part 30 . 5(a) and 5(b), the measuring rod 20 is configured to be detachable from a presser plate 32d located below the biasing spring member 30. For example, the presser plate 32d is provided with a through-hole 41 through which the upper part of the measuring rod 20 passes. After the upper part of the measuring rod 20 is inserted into the through-hole 41 of the presser plate 32d, a retaining mechanism 42 prevents the upper part of the measuring rod 20 from being removed from the presser plate 32d. Here, the retaining mechanism 42 may be configured such that pin holes 43 and 44 are formed in the upper part of the measuring rod 20 at a distance substantially corresponding to the thickness of the presser plate 32d. After the upper part of the measuring rod 20 is inserted into the through-hole 41 of the presser plate 32d, R-shaped snap pins 45 and 46 are inserted into the pin holes 43 and 44 of the measuring rod 20, and a washer 47 is interposed between at least one of the snap pins 45 and the presser plate 32d. In this example, by removing the snap pins 45, 46 of the retaining mechanism 42, the measuring rod 20 can be easily detached from the biasing spring part 30. Therefore, in this example, when transporting the soil hardness measuring instrument D, the transport space can be made compact with the measuring rod 20 detached from the soil hardness measuring instrument D.

[0023] -Adjustment mechanism- Furthermore, in this example, the biasing spring component 30 is provided with an adjustment mechanism 50 as an adjustment means for adjusting the biasing force of the biasing spring 31. As shown in FIGS. 2 and 3 , this adjustment mechanism 50 has an adjustment rod 51 that penetrates approximately the center of the ceiling wall 11c facing the bottom wall 11b of the holder main body 11. In this example, the adjustment rod 51 has a rod main body 51a with a circular cross section, and a male thread portion 51b is formed at least in an adjustable range of the rod main body 51a. An operating handle 51c that protrudes radially from the rod main body 51a is provided at the upper end of the rod main body 51a, allowing the adjustment rod 51 to be rotated. Meanwhile, an insertion hole (not shown) is formed approximately in the center of the ceiling wall 11c, and a nut 52 is provided as a fastener at the edge of the insertion hole on the surface side of the ceiling wall 11c. The male thread portion 51b of the adjustment rod 51 is attached in a state where it is threadedly engaged with the nut 52. If necessary, a holding lever 52a can be added to the nut 52 as shown by the imaginary line.

[0024] Furthermore, the lower end of the rod main body 51a is fixed to approximately the center of a presser plate 32u located above the biasing spring component 30. As a fixing method, for example, a male threaded portion 51d (which in this example also serves as the male threaded portion 51b at the upper part of the rod main body 51a) is formed at the lower part of the rod main body 51a, an insertion hole (not shown) through which the lower part of the rod main body 51a can be inserted is formed at approximately the center of the presser plate 32u, a fixing nut 54 is fixed to the edge of the insertion hole, and the male threaded portion 51d of the rod main body 51a is screwed onto the fixing nut 54. In this example, the lower part of the adjustment rod 51 is fixed to the pressure plate 32u with screws, and the pressure plate 32u moves downward in response to the downward movement of the adjustment rod 51. However, this is not limited to this. It is also possible to form a receiving portion (not shown) at approximately the center of the pressure plate 32u to receive the lower end of the adjustment rod 51, and position the lower end of the adjustment rod 51 in contact with the receiving portion of the pressure plate 32u, so that the pressure plate 32u moves downward in response to the movement of the adjustment rod 51. In addition, in this example, since the adjustment mechanism 50 adjusts the biasing force of the biasing spring 31 of the biasing spring part 30, it is preferable that the biasing direction of the biasing spring part 30 is along the axial direction of the measuring rod 20. For this reason, in this example, the measuring rod 20 and the adjustment rod 51 of the adjustment mechanism 50 are arranged coaxially.

[0025] Next, a method for using the adjustment mechanism 50 will be described. First, to adjust the biasing force of the biasing spring component 30 to a larger value, the following operation can be performed. Specifically, as shown in FIGS. 6(a) and 6(b), by gripping the operating handle 51c and rotating the adjustment rod 51 in a predetermined screwing direction, the male thread portion 51b of the adjustment rod 51 is screwed into the nut 52. At this time, the adjustment rod 51 presses down a predetermined amount on the retainer plate 32u located above the biasing spring component 30. As a result, the span s between the pair of retainer plates 32 becomes shorter, and accordingly, the biasing spring 31 sandwiched between the pair of retainer plates 32 is further compressed and deformed by the amount of the retainer plate 32u pressed down. As a result, the biasing force of the biasing spring 31 increases.

[0026] On the other hand, to adjust the biasing force of the biasing spring component 30 to a smaller value, the following operation can be performed. Specifically, by gripping the operating handle 51c and rotating the adjustment rod 51 in a predetermined non-threading direction, the male thread portion 51b of the adjustment rod 51 moves in a direction that disengages it from the nut 52. At this time, the retaining plate 32u fixed to the tip of the adjustment rod 51 moves upward by a predetermined amount. As a result, the span s between the pair of retaining plates 32 becomes longer, and accordingly, the compressive deformation of the biasing spring 31 sandwiched between the pair of retaining plates 32 is reduced. As a result, the biasing force P of the biasing spring 31 decreases. In this way, when the adjustment rod 51 moves axially by a distance h following the rotation of the adjustment rod 51, the span s between the pair of pressure plates 32 is determined accordingly, and the biasing force P of the biasing spring 31 is also determined.

[0027] -Conversion equipment- Furthermore, in this example, as shown in Figures 3 and 4(a)(b), a conversion device 60 is provided as a conversion means for converting the measurement rod 20 into an electrical signal that depends on the amount of retraction d from the initial position of the measurement rod 20 (see Figure 6(b)). In this example, the conversion device 60 includes a variable resistor 61 that converts depending on the amount of retraction d of the measuring rod 20 from its initial position, and an oscillator board 65 that constitutes a variable oscillator as an oscillation means whose oscillation frequency changes depending on the resistance value of the variable resistor 61.

[0028] <Variable resistor> In this example, the variable resistor 61 is, for example, a slide volume type. The variable resistor 61 has a variable resistor 62 (see FIG. 4(b)) extending in the same direction as the axial direction of the measuring rod 20, and a slidable movable indicator 63 that changes the resistance value of the variable resistor 62. In this example, the variable resistor 61 is attached to a part of the inner surface of the side wall 11d of the holder body 11 via a mounting bracket 64. In this example, the movable indicator 63 moves up and down in conjunction with the presser plate 32d, which serves as a follower member that follows the retraction of the measuring rod 20. Specifically, the movable indicator 63 is composed of a rod-shaped member that protrudes substantially horizontally outside the case of the variable resistor 61. The presser plate 32d has a concave groove 33 on its outer periphery. The tip of the movable indicator 63 is hooked into the groove 33 of the presser plate 32d. In this example, the resistance value R of the variable resistor 62 of the variable resistor 61 increases approximately in proportion to the retraction amount d of the measuring rod 20, as shown in FIG. 7(a).

[0029] <Oscillator board> In this example, the oscillator board 65 is detachably attached to the inner surface of the door 12 of the holder 10, as shown in FIGS. 4(a) and 4(b). In this example, a power supply 70 is mounted inside the holder body 11 (see FIG. 3). Furthermore, a power supply connector 66 connectable to the power supply 70 and a resistor connector 67 connectable to the variable resistor 61 are provided at the input end of the oscillator board 65. Therefore, the oscillator board 65 is connected to the power supply 70 and the variable resistor 61 via the connectors 66 and 67 described above. In this example, the oscillator board 65 converts the signal into an electrical signal with a different frequency depending on the resistance value of the variable resistor 62 of the variable resistor 61 and outputs the converted signal. In this example, the oscillator board 65 outputs an electrical signal with a lower frequency as the resistance value of the variable resistor 62 becomes smaller, and outputs an electrical signal with a higher frequency as the resistance value of the variable resistor 62 becomes larger. For example, as shown in FIG. 7(b), if the resistance value R of the variable resistor 62 changes from Ra to Rb (>Ra), the frequency f of the electrical signal output from the oscillator board 65 changes accordingly from fa to fb (>fa).

[0030] -Speaker- Furthermore, in this example, a speaker 80 serving as a warning means is connected to the output terminal of the oscillator board 65, as shown in Figures 4(a) and (b), and this speaker 80 is detachably attached to the inner surface of the door 12 of the holder 10. The speaker 80 is configured to emit warning sounds corresponding to the electrical signals of different frequencies f output from the oscillator board 65. In this example, as shown in Fig. 7(c), the speaker 80 emits a lower sound as the frequency f of the electrical signal decreases, and a higher sound as the frequency f of the electrical signal increases. In particular, it is preferable to adjust the acoustics so that in fields with appropriate soil hardness, a low sound that is comfortable to humans is emitted as the OK range, and in fields with soil hardness that is harder than the appropriate value, a high-pitched sound that is uncomfortable to humans is emitted as the NG range.

[0031] -Other equipment- Furthermore, in this example, as shown in FIG. 3, a warning mechanism 90 is provided as a restricting means for restricting the retraction amount d of the measuring rod 20 from its initial position so that it does not exceed the initial position. The warning mechanism 90 has a microswitch 91 as a detecting means for detecting when the retraction amount d of the measuring rod 20 from its initial position reaches a predetermined threshold. In this example, the microswitch 91 is arranged to turn on when the pressure plate 32u of the biasing spring component 30, which follows the retraction movement of the measuring rod 20, has retracted to a predetermined position. The microswitch 91 is connected to an indicator lamp 92 provided on the top wall 11c of the holder main body 11, and the indicator lamp 92 lights up in conjunction with the turning on of the microswitch 91. The indicator lamp 92 may be lit in any color, but in this example, a red light is used to draw attention.

[0032] -Preparation before using soil hardness measuring equipment- In this embodiment, before using the soil hardness measuring instrument D, it is necessary to initially set the biasing force of the biasing spring component 30. First, in order to select the soil hardness suitable for the crop (e.g., Chinese yam or Japanese yam) of the soil A to be measured and the soil hardness that is unsuitable, it is necessary to initially set the biasing force of the biasing spring part 30 so that when measuring unsuitable soil hardness, a high-pitched warning sound is emitted from the speaker 80. For this reason, in this example, as shown in Figure 6(a), the measurement rod 20 of the soil hardness measuring instrument D is inserted into several places in reference soil A0 of a field known in advance to be unsuitable soil (a field where the shape of potatoes is compact and the roots are bent), and the biasing force of the biasing spring component 30 is adjusted so that a high-pitched sound is emitted from the speaker 80 as a warning sound. In this case, to adjust the biasing force P of the biasing spring part 30, as shown in Figure 6(b), the measuring rod 20 of the soil hardness measuring instrument D is inserted into a known field, and the adjustment rod 51 of the adjustment mechanism 50 is rotated appropriately in the screwing direction or the non-threading direction, and the span s between the pair of pressure plates 32 of the biasing spring part 30 is selected to determine the biasing force P by the biasing spring 31, so that a high-pitched sound is emitted from the speaker 80. Furthermore, since the hardness of soil A varies greatly depending on the moisture content in the soil, it is preferable to select a date and time when the moisture tension pF value of the soil measured by the tension meter 100 is 2.0 or higher, and then initially set the biasing force P of the biasing spring component 30.

[0033] -Measurement work using soil hardness measuring equipment- <Confirmation of the suitability of the measurement date and time> First, to confirm whether the moisture content of the soil A (e.g., A1 or A2) to be measured is appropriate, the soil moisture tension pF value measured by a tension meter 100 is confirmed to be 2.0 or higher, as shown in Figure 8(a) or (b). If the pF value is less than 2.0, the soil moisture content is high, which raises the risk of mistaking soil that should be measured as inappropriate for proper soil quality. For this reason, it is preferable to change the measurement date and time if the pF value is less than 2.0. Generally, if fine weather continues for 4 to 5 days after rainfall, the pF value often reaches 2.0.

[0034] <Example of using soil hardness measuring equipment> If the moisture ratios of the soils A1 and A2 to be measured are appropriate, the hardness of each of the soils A1 and A2 is measured using the soil hardness measuring instrument D, for which the initial settings for the biasing spring component 30 have been completed. In this example, it is assumed that the soil A1 has an appropriate hardness, and the soil A2 has an inappropriately hard hardness. In this case, as shown in Figure 8(a) or (b), the operator grasps the gripping arm 17 of the holder 10 of the soil hardness measuring instrument D and holds the soil hardness measuring instrument D in a position that is approximately vertical, then presses the tip of the measuring rod 20 against the surface of the soil A1 or A2 to be measured, and uses his / her body weight to push the measuring rod 20 in. At this time, the measuring rod 20 retracts against the biasing force P of the biasing spring part 30 depending on the hardness of the soil A (A1 or A2). In this example, the soil A1 has an appropriate hardness, so the retraction amount d of the measuring rod 20 from its initial position is small. In contrast, the soil A2 has an inappropriately hard hardness, so the retraction amount d of the measuring rod 20 from its initial position is large. Here, the retraction amount of the soil A1 from its initial position is d1, and the retraction amount of the soil A2 from its initial position is d2 (>d1).

[0035] In this state, as shown in FIG. 7(a), the resistance value R of the variable resistor 62 of the variable resistor 61 changes in proportion to the retraction amount d of the measuring rod 20. 7(b), the frequency f of the electrical signal output from the oscillator substrate 65 changes in proportion to the resistance value R of the variable resistor 62 of the variable resistor 61. Furthermore, as shown in FIG. 7(c), the sound of the speaker 80 changes from a low pitch to a high pitch (high-pitched sound in this example) depending on the frequency f of the electrical signal output from the oscillator board 65. Therefore, in this example, when the hardness of soil A1 is measured, the retraction amount d1 of the measuring rod 20 falls within the OK region where the soil hardness is appropriate, as shown in Figure 8(c). Therefore, a low warning sound is generated from the speaker 80 based on the frequency f of the electrical signal converted depending on the retraction amount d1 of the measuring rod 20.

[0036] On the other hand, when measuring the hardness of soil A2, the retraction amount d2 of the measuring rod 20 falls within the NG region, where the soil hardness is inappropriately hard, as shown in Figure 8(c). Therefore, a high-pitched warning sound is generated from the speaker 80 based on the frequency f of the electrical signal converted depending on the retraction amount d2 of the measuring rod 20. Therefore, the worker using the soil hardness measuring instrument D can distinguish by hearing whether the warning sound from the speaker 80 remains low or has changed to a high-pitched sound. Therefore, the worker can intuitively determine whether the hardness of the soils A1 and A2 is appropriate or inappropriate based on the warning sound from the speaker 80.

[0037] -Transporting soil hardness measurement equipment- In this example, when transporting the soil hardness measuring instrument D, it is possible to transport the soil hardness measuring instrument D in an assembled state, but in this example, it is also possible to partially disassemble the soil hardness measuring instrument D to reduce the storage space required for transportation. In this example, the measuring rod 20 and the spring component 30 are configured as a disassembly assembly unit 40, so that the measuring rod 20 can be detached from the pressure plate 32d of the spring component 30, as shown in Figures 5(a) and (b), and the measuring rod 20 can be transported in a separated state from the soil hardness measuring instrument D. In this example, the conversion device 60 can be connected to the power supply 70 and the variable resistor 61 via connectors 66 and 67, respectively. Therefore, when transporting or storing the soil hardness measuring instrument D, or when cleaning the inside of the holder 10, it is preferable to disconnect the connectors 66 and 67.

[0038] ◎Transformation form 1 In this embodiment, the soil hardness measuring instrument D is configured to give a warning sound to the auditory sense, but this is not limited to this, and it can also be configured to give a warning to the visual sense, for example. FIG. 9(a) is an explanatory view showing the main parts of a soil hardness measuring instrument according to a first modified embodiment. In the figure, the soil hardness measuring instrument D includes a holder 10, a measuring rod 20, a biasing spring component 30, and an adjustment mechanism 50, similarly to the first embodiment. However, the soil hardness measuring instrument D of this embodiment includes a converter 110 and a warning lamp 120 that are different from those of the first embodiment. The converter 110 and the warning lamp 120 are supplied with power from the power source 70.

[0039] 9(b), the conversion device 110 includes a variable resistor 61 similar to that of the first embodiment, and a switch 111 that switches a current path depending on the resistance value of the variable resistor 61. Here, similar to the first embodiment, the resistance value of the variable resistor 61 changes depending on the retraction amount d of the measuring rod 20 from the initial position. In this example, the resistance value of the variable resistor of the variable resistor 61 increases as the retraction amount d of the measuring rod 20 increases. The switch 111 switches the current path depending on the resistance value of the variable resistor of the variable resistor 61. In this example, the resistance range of the variable resistor is divided into, for example, a small resistance range, a medium resistance range, and a large resistance range. The switch 111 has a movable contact 112 whose position changes depending on the resistance value of the variable resistor, and a plurality of contacts 113 to 115 corresponding to the ranges to which the resistance values ​​of the variable resistor belong, and operates to switch the current path by bringing the movable contact 112 into contact with any of the contacts 113 to 115.

[0040] The warning lamp 120 also has a plurality of light sources 121-123 whose colors change depending on the level of the warning. In this example, these light sources 121-123 are configured, for example, with light-emitting diodes. Here, the first light source 121 emits a green light indicating that the soil hardness is appropriate, the third light source 123 emits a red light indicating that the soil hardness is inappropriately hard, and the second light source 122 emits a yellow light indicating that the soil hardness is in a borderline region between appropriate and inappropriate.

[0041] In this example, when using the soil hardness measuring instrument D, first check the moisture ratio of the soil A to be measured, then hold the soil hardness measuring instrument D in a position approximately vertical to the surface of the soil A, and press the tip of the measuring rod 20 against it to push the measuring rod 20 in. At this time, the retraction amount d of the measuring rod 20 from the initial position changes depending on the hardness of the soil A. In this state, if the hardness of the soil A is appropriate, the retraction amount d of the measuring rod 20 is small, so the resistance value of the variable resistor of the variable resistor 61 of the conversion device 110 falls within the small resistance range, and the switch 111 switches to the first current path in which the movable contact 112 is connected to the first contact 113. As a result, the first light source 121 of the warning lamp 120 lights up in green.

[0042] Furthermore, if the hardness of the soil A is inappropriately hard, the retraction amount d of the measuring rod 20 becomes large, so that the resistance value of the variable resistor of the variable resistor 61 of the conversion device 110 becomes a large resistance range, and the switch 111 switches to the third current path in which the movable contact 112 is connected to the third contact 115. As a result, the third light source 123 of the warning lamp 120 lights up in red. Furthermore, when the hardness of soil A is in the borderline range between appropriate and inappropriate, the retraction amount d of measuring rod 20 is somewhere between the first two, so the resistance value of the variable resistor of variable resistor 61 falls in the medium resistance range, and switch 111 switches to the second current path in which movable contact 112 is connected to second contact 114. As a result, second light source 122 of warning lamp 120 lights up in yellow. [Industrial Applicability]

[0043] According to the soil hardness measuring instrument of the present invention, when measuring soil hardness, instead of measuring the soil hardness numerically, a warning can be given to the operator if the soil hardness is inappropriate, so that the operator can intuitively know that the soil hardness is inappropriate. In this way, when measuring soil hardness numerically, there is a concern that the soil hardness may be judged incorrectly due to errors in reading the numbers during measurement, but the soil hardness measuring instrument of the present invention makes it possible to accurately judge whether the soil hardness is inappropriate. [Explanation of symbols]

[0044] 1...holder, 1a...holder body, 1b...door, 2...measuring rod, 3...biasing means, 4...conversion means, 4a...variable resistance means, 5...warning means, 6...adjusting means, 7...guiding member, 8...fixing device, 9...power source, A...soil, d...retraction amount of measuring rod, D...soil hardness measuring device

Claims

1. a holder that can be held by a worker; a measuring rod that protrudes below the lower part of the holder so that its tip comes into contact with the soil to be measured and is movable up and down relative to the holder; a biasing means provided in the holder for biasing the measuring rod downward so that the measuring rod can be retracted from a predetermined initial position; a conversion means provided in the holder for converting the measured value into an electrical signal depending on the amount of retraction of the measuring rod from its initial position; a warning means provided in the holder for issuing a warning in response to an output from the conversion means; A soil hardness measuring instrument comprising:

2. 2. The soil hardness measuring instrument according to claim 1, the conversion means has variable resistance means whose resistance value changes depending on the amount of retraction of the measuring rod from its initial position, 10. A soil hardness measuring instrument, wherein the warning means issues a warning that varies depending on the resistance value of the variable resistance means.

3. 3. The soil hardness measuring instrument according to claim 2, The soil hardness measuring instrument is characterized in that the conversion means has an oscillation means that converts a change in the resistance value of the variable resistance means into an electrical signal of a frequency corresponding to the change in the resistance value, and the warning means has an acoustic means that changes the sound of the warning in accordance with the electrical signal from the oscillation means.

4. 2. The soil hardness measuring instrument according to claim 1, The soil hardness measuring instrument is characterized in that the holder is provided with an adjustment means for adjusting the biasing force exerted by the biasing means on the measuring rod.

5. 2. The soil hardness measuring instrument according to claim 1, A soil hardness measuring instrument characterized in that the holder has a hollow holder body with one open side and a door for opening and closing the opening of the holder body, and all or part of the warning means and the conversion means are mounted on the door side.

6. 2. The soil hardness measuring instrument according to claim 1, 10. A soil hardness measuring instrument, wherein the measuring rod and the biasing means are assembled as a single assembly unit that can be disassembled.

Images