RU230073U1 - DEVICE FOR DETERMINING SOIL HARDNESS IN THE PLOUGH AND SUB-PLOUGH HORIZONS - Google Patents

Abstract

The utility model relates to methods and technical means for determining the physical parameters of soil, in particular for studying the soil hardness in the plough and sub-plough horizons to a depth of up to 80 cm when testing agricultural technologies. The purpose of the utility model is to create a small-sized device for measuring the soil hardness in order to assess the physical parameters of the soil in the plough and sub-plough horizons. The said technical result is achieved by the fact that instead of a reversible electric motor with a reducer and a gear coupled with a movable toothed rack fixed to the housing, and a strain gauge sensor, a rod and a plunger fixed to this rack, two toothed racks are fixed inside the housing, and a movable carriage with toothed gears fixed in it, a reversible electric motor with a reducer, a strain gauge motor, a rod and a plunger move along these racks.

Description

The utility model relates to methods and means for determining the hardness of the soil, in particular for measuring the hardness of the soil layer in the plow and sub-plow horizons during testing of agricultural technologies and soil-cultivating machines in order to justify the selection of the most effective methods of its cultivation.

The purpose of the utility model is to automate the process of measuring soil hardness in plow and sub-plow horizons.

The device soil hardness tester NPP KHARTRON-ENERGY is known to determine the physical, mechanical and technological properties of the soil by measuring the resistance to penetration of a plunger of a certain shape into it with simultaneous geographic referencing to the terrain using a GPS receiver. Using cylindrical plungers, the resistance to soil compaction is determined, and using conical plungers, the resistance of the soil to the wedging force. Information about the measurements performed is displayed on the device in the form of graphs or tables. In the known device, the plungers are inserted manually by the operator, which does not allow for a constant plunger immersion speed. Multiple studies have proven that, other things being equal, at different plunger immersion speeds, the measured soil hardness values do not coincide.

A device for measuring the physical properties of soils, which allows for high-precision measurement of soil hardness in field conditions, is known; it is presented in the patent for utility model RU 214385, IPC GO1N 3/40, published on 10/25/2022, “Device for Measuring Soil Hardness”.

The device works as follows.

In the specified place, place the hardness tester with its base on the soil in a vertical position. Holding the device by the upper support plate, press on the handle. The force is transmitted to the movable plate, which, moving along the guide rods, acts on the rod with a movable pressure plate and a spring. Compressing, the spring presses the replaceable tip into the soil.

When the movable pressure plate moves downwards, the projection pulls the rod of the potentiometric linear displacement sensor. The signal from the sensor is sent to the converter, and after being converted to the unit of measurement kg/ ^cm2, it is output to the display module.

After the load is removed from the handle, the spring is released and the tip returns to its original position. The results are saved on the display module (peak value) until the next measurement or the device is turned off. In this device, the tip is also deepened by the force applied manually by the operator.

When measuring hardness on heavily compacted or dried soil, great efforts are applied to the handle of the hardness tester to deepen the tip. Torsional loads increase on the hardness tester, which loosen the attachment points of the guide rods with the upper support plate and the base.

The disadvantage of this device is that the rod is immersed into the soil by the operator's muscular force, the immersion speed is not constant and when taking measurements on compacted or dried soil, sometimes the operator's efforts may not be enough to take measurements.

A measuring device is known, described in the patent for invention RU 2791146, IPC GO1N 3/40, published on 03.03.2023 "Device for measuring soil hardness". The proposed invention relates to instruments for determining the hardness of the soil in the root layer of agricultural plants at various depths, including at depths exceeding one meter, with recording of the results on a video device.

The device for determining the soil hardness (hardness tester) consists of a handle on which a platform with paper, a guide sleeve with an upper plate, a vertical ruler, a limiting rod and a vertical bracket with a tape measure are fixed. A cylindrical vertical rod with an index plate and a horizontal nut is movably mounted in the guide sleeve. A video camera is additionally fixed to the horizontal bracket on the upper plate on the outside using a threaded connection. And inside it there is a cylindrical spring limited from below by a lower plate fixed on the cylindrical vertical rod by a lock bolt with a lock nut. At the lower end of the vertical cylindrical rod above the calibrated tip there is additionally mounted a support shoe with an internal conical opening and with a recess for the calibrated tip. The tape measure cloth is additionally hinged to the support shoe through the tape measure tip. To hold and adjust the vertical ruler, the device has a plate which, together with the paper platform and the limiting rod on the handle, is held by a clamp with vertical nuts.

The disadvantage of this device is that, as in the above-described devices, the plunger rod is lowered by the operator's efforts, the measuring device in the device is a spring with a fixed pointer and an index plate. The spring stiffness may change over time and, in addition, depends on the ambient temperature. The accuracy of measuring the soil hardness indicators determined visually by the position of the index plate moving along the vertical ruler will be low.

A device described in the patent for utility model RU 199862, IPC G01N 9/00, published on September 23, 2020, “Device for measuring soil hardness for coordinate farming” is known.

The device consists of a housing with a base, a reversible electric motor with a reducer, a gear with a toothed rack, a strain gauge, a rod and a plunger, an incremental encoder and an electronic unit, which includes a GPS/GLONASS module, fixed to the device housing and having non-volatile memory. The plunger immersion depth into the soil is determined by the number of pulses of the incremental encoder. The soil hardness control process is carried out using a strain gauge, and the results are stored in the non-volatile memory of the electronic unit. The device operates using a reversible electric motor with a reducer powered by a battery, fixed to the device housing. The transmission of rotational motion from the reversible electric motor, reducer and gear ensures reciprocating motion relative to the housing of the interconnected toothed rack, strain gauge, rod and plunger. The encoder fixed to the gear shaft allows determining the speed and depth of plunger immersion. Under the action of soil resistance, through the rod and plunger, the pressure is transmitted to the strain gauge sensor, the signals from which are sent to the electronic unit for subsequent conversion. Upon completion of the measurement, the data received from the strain gauge sensor, encoder and the coordinates of the measurement location are recorded in the non-volatile memory of the device.

The disadvantage of the device is the insufficient plunger immersion depth - 40 cm, which is due to the design of the device itself. The moving part of the device, consisting of a rod with a plunger (50 cm), a carriage with a strain gauge attached to it (15 cm) and a toothed rack (50 cm), determines the overall height of the device (≈1.5 m). To study the condition of the soil in the plow and sub-plow horizons, it is necessary to determine the soil hardness to a depth of 80 cm. With such a design solution, the height of the device will reach about 3 meters, and its weight will become an insurmountable obstacle to practical use.

Based on a combination of features, a device for measuring soil hardness for coordinate farming (patent for utility model RU 199862) is accepted as the closest analogue.

The purpose of the utility model is to provide the ability to monitor the soil hardness in the plow and sub-plow horizons, automate the process of obtaining data and save the entire sequence of measurements in non-volatile memory for further statistical processing of the obtained data and mapping of the obtained results for a precision farming system.

Based on the results of the analysis, a new electromechanical device was developed for measuring soil hardness to a depth of 80 cm, which has dimensions and weight parameters acceptable for practical use.

The claimed device consists of a housing in which two toothed racks 6, 1 meter long (Fig. 1), are fixedly secured, a movable carriage 3, on which gears 2, a reversible motor 11 with a gearbox 10 and a strain gauge sensor 9 are secured. A rod with a plunger 5 is connected to the strain gauge sensor. At the top, the housing and toothed racks are connected by a plate 1, on which an electronic unit is secured, and at the bottom - by support platforms with brackets 8. Upper 4 and lower 7 carriage position sensors are installed on the hardness tester housing.

The process of measuring soil hardness is as follows:

the support pads are moved to a horizontal position, and the hardness tester is placed at the point where the measurement needs to be taken;

the electronic unit is turned on;

after the initialization mode is completed and the Start button is pressed, a 12 V supply voltage is supplied to the reversible motor with a gearbox;

rotation from the gearbox shaft is transmitted to the gear, and the carriage with the reversing motor, gearbox, strain gauge and rod with plunger attached to it begins to move down the toothed racks;

When the carriage sensor reaches the lower position, the carriage movement stops, the data obtained during the experiment is saved in non-volatile memory, and the carriage returns to its original position.

In the proposed design of the device, due to the use of two fixed toothed racks and two gears fixed on a movable carriage, which are driven by a reversible gear motor, it was possible to reduce the dimensions of the device (≈1.2 m), while the depth of soil hardness measurement increased to 80 cm. At the same time, all the advantages of the analogue are preserved:

electromechanical drive;

constant plunger immersion speed;

storing in non-volatile memory data on soil hardness throughout the entire depth of plunger immersion and the coordinates of the experiment.

Claims (1)

A device for measuring soil hardness, comprising a housing with a base, a reversible electric motor with a gearbox, a strain gauge, a rod with a plunger, characterized in that it additionally contains two toothed racks fixedly secured inside the housing, a movable carriage on which gears are secured, a reversible electric motor with a gearbox, and a strain gauge to which the rod with a plunger is connected, wherein the housing and toothed racks are connected at the top by a plate on which an electronic unit is secured, and at the bottom by support platforms with brackets.