The present invention relates to a soil sampling device, more particularly to a hand held soil sampler.
Description of the Related Art
Soil Sampling is the first step towards soil management in an agriculture field. This gives us a baseline as far as soil nutrients status is concerned. This further helps us in preparation of fertilizer plan, water management and it's several applications to improve farm productivity. The Soil Sampling gives farmers a lot of information on how to manage the farms in terms of moisture (watering), fertilizers, nutrients, pollution, etc.
Soil samples (usually the top 7 inches or so of the topsoil) are taken from farm fields and sent to a soil analysis lab to analyze the different soil nutrients contained in the samples. This analysis is used to determine the correct amount of nutrients to apply to farm fields. There could be considerable variability of nutrient content in soil samples taken from different locations in a farm field. The only way to accurately measure this variability is to increase the number of samples taken within a field. But with conventional soil sampling techniques and mechanisms, this can become cost prohibitive due to the time required to collect the samples.
Soil is also sampled for various reasons, such as a farm that is being prepared for planting, or the growing plants may be treated with chemicals such as herbicides, pesticides and fertilizers. At some period of time after treatment, samples of the soil are collected and analyzed to determine the depth to which the chemical has penetrated the soil and the activity (persistence) of the chemical at different depths.
The basic tool used for the collection of undisturbed soil samples from test pits or boreholes at required depth is known as a soil sampler. The fundamental requirement

of a sampling tool is that when it is forced into the ground, it should cause as little displacement, remolding, and disturbance to the soil as possible.
A typical Soil Sampler will be used for visual inspection and laboratory testing for the determination of the soil unit geological provenance, characteristics and geotechnical engineering design parameters. It is used to collect virtually undisturbed soil core samples for soil profiling and environmental investigations. All of these quality soil core sampling tools allow the user to collect soil core samples into removable liners.
We refer to US Patent No. 3696873A titled as Soil Sampling Device by Inventor Gene A Anderson, Dow Chemical Co. The invention describes the basic components of the device - a sample tube, driver sleeve, driver cap and driver head. The sample tube is a pipe which is split lengthwise into two semicircular sections. In assembled position, i.e. during the soil collecting function, the split sample tube is a unitary tube which fits inside a larger pipe that defines the driver sleeve. The driver cap is an internally threaded cup-shaped member with an upstanding solid stem thereon and a crosswise handle. The cap is secured to the upper end of the driver sleeve by external threads on the sleeve. The driver head is a one-piece member comprising a solid block, a hollow stem which fits over the solid stem of the driver cap, and loop-type handles. The loop handles enable the driver head to be lifted up and down, so that the driver stem can hammer down against the cap and thereby drive the sleeve and sample tube into the earth.
The following design features of the sampling tool control the degree of disturbance:
1. Cutting edge.
2. Inside-wall friction.
3. Non-return valve.
Several commercial devices are available for collecting soil samples. One such device is known as a nematode probe. The nematode probe is a T-shaped device having a hollow shank with an open end which is attached to a crosswise handle. Along one side of the shank is a lengthwise slot. A soil sample is obtained by pushing the probe

into the ground, so that soil is forced up into the shank through the open end. When the probe is pulled upward out of the earth, the soil sample can be removed from the slot. A particular disadvantage of this device is that upon pulling the probe out of the ground the soil sample collected in the shank slot will scrape against the sides of the hole and thus become contaminated with foreign soil.
Another common soil sampling tool is an auger-type device. Soil samples are obtained at different depths, in sequence, by removing the first sample from the auger and then reinserting the auger in the same hole for the second sample and each succeeding sample. The auger probe has essentially the same drawback as the ne-v matode probe; i.e. each time the probe is reinserted in the hole it will dislodge soil which contaminates the next sample. With either of the devices described above, therefore, it is virtually impossible to obtain an accurate analysis of the soil composition at different depths.
Further, our prior art searches have revealed the following patents internationally.
CN201837538 - Abstract - The utility model discloses a manual sampling hammer and a manual soil sampler provided with the same. The manual sampling hammer comprises a housing, a manual cam mechanism, a pressure seat, an elastic component, a hammer sheath and a lower hammer head, wherein the pressure seat is used for sealing one end of the housing; the elastic component, the hammer sheath and the lower hammer head are mounted in the housing; the elastic component is arranged between the pressure seat and the hammer sheath; the hammer sheath is arranged between the elastic component and the lower hammer head; and the manual cam mechanism and the hammer sheath are in driving connection with each other, so as to drive the hammer sheath to move axially along the housing, which ensures that the elastic component stores or releases energy. The manual soil sampler comprises the manual sampling hammer and a sampling barrel, wherein the sampling barrel is connected with the lower hammer head of the manual sampling hammer through a universal driving shaft and comprises an inner barrel and an outer barrel which are in threaded connection with each other. The manual sampling hammer provided by the utility model has the advantages that the beating strength can be

adjusted conveniently; the sampling time can be shortened effectively; the carrying is convenient; the operation is simple and convenient; the sampling procedure and the sampling operation are simple and fast; and the soil sampling time is shortened.
US5186263 (A) - Abstract - A device for obtaining soil samples beneath the surface of the ground. A sample tube is provided with a removable piston tip blocking the forward opening of the sample tube. Rearward movement of the piston tip is blocked by a removable piston stop. The sample tube is driven into the soil with the piston tip blocking its forward end. Tubular probe extension may be successively added to the rear of the device to allow driving of the sample tube to the desired depth. At the desired depth, the piston stop is removed to unblock the piston tip. The piston stop may be removed by a series of threadedly connected extension rods threadedly connected via a drivehead to the piston stop. The piston stop is threadedly connected to the sample tube with left-handed threads to ensure all other connections remain tight during removal. The sample tube is then driven forward, causing the soil sample to enter the tube and the tip to slide within the tube. The tube is then withdrawn from the soil to recover the sample.
GB2276897-Abstract- An apparatus for soil sampling and testing comprising a tubular casing (8) having a longitudinal bore (22), a sampling tube (2) for taking a soil sample from within the longitudinal bore for testing, and an air displacement hammer (4). The casing (8) has an internal shoulder (26) against which the hammer (4) abuts in order to drive the casing (8) vertically into the ground. The sampling tube (2) is attached to the hammer (4) and is limited in its downward movement within the casing (8) the hammer (4) striking the internal shoulder (26).
Despite the existence of several related arts, devices and solutions, there exists a need to overcome shortcomings and provide soil sampler devices that are affordable and suitable for extreme tropical environments and could be used to extract causing minimum disturbance to soil.
SUMMARY OF THE INVENTION

An object of the present invention is to provide a thin walled soil sampler that extracts samples with minimum disturbance to soil.
One more object of the present invention is to provide at least clearance of 20 mm between the top of sampling-ring and the bottom surface of ring-holder that avoids compaction of soil mass during sampling process.
Yet another advantage of the present invention is that it could also be used to calculate the dry density, bulk density and volumetric water content of soil.
An additional advantage of the present invention is that it provides for an overall design that facilitates faster sampling of soil cores.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Figure 1 is a typical 2D illustration of soil moisture sampler (a) ring-holder and (b) sampling-ring.
Figure 2 is a perspective view of soil sampler.
Figure 3 is picture of a typical soil sampler.
Figure 4 to Figure 6 details the process of sampling the soil.
Figure 4 is a Soil sampler connected with a sliding hammer.
Figure 5 is a typical process of sampling-ring inserted into soil.

Figure 6 depicts a process of trimming off excess soil.
DETAILED DESCRIPTION
The present invention involves a soil sampler for the purpose of extracting soil samples from the surface. The sampler is composed of two parts- a sampling-ring and a ring-holder. It is appreciated that present invention can be implemented in a variety of apparatus, systems, devices, architectures and configurations. In the present description, some words are being used interchangeably to mean the same thing/ entity: Customers' & 'Users'; 'He' & "She".
The invention tries to sample precise volume of soil equal to that of volume of sampler-ring that facilitates the measurement of many soil properties- (i) volumetric water content of soil, (ii) bulk density of soil, and/ or (iii) dry density of soil.
[0001] Figure 1 is a typical 2D illustration of soil moisture sampler with a) ring-holder and (b) sampling-ring. The sampling ring has a tapered edge on one end to achieve smooth insertion in soil. The ring-holder is also tapered to provide smooth insertion into soil. The wall of soil sampler is typically only about 1.5 mm, which causes minimum disturbance to the soil during the sampling process. The thin wall of sampler also offers lesser resistance during insertion in the soil. The ring-holder stops the sampling-ring from deforming and bulging out. A clearance of 20 mm is provided between the top of sampling-ring and the inner surface of ring-sampler to avoid compaction of soil during sampling. A hole of 3 mm is provided on the top surface of ring-holder to allow passage of air during sampling.
The volume of collected soil is equal to that of volume sampling ring (V), which is calculated as -
V = nr2h = 7r{l.\ cm) x5 cm = 69.27 cm3

Figure 2 is a perspective view of soil sampler. It shows the sampling ring and ring holder placed side by side.
Figure 3 is a picture of a typical soil sampler.
Figure 4 to Figure 6 details the process of sampling the soil. The working of the invention can be described or explained as under:
• The sampling-ring is inserted in the ring-holder with tapered end outside.
• Then the sampler is connected to a sliding hammer or to a rod extension, which provides a base for blows by hammer/mallet.
• Gentle blows are given to the sampler unit, which drives the sampling-ring into the soil.
• Stop the blows when the soil surface reaches the marking.
• Remove the sampling ring from the ring-holder and trim-off the excess soil, which is outside the sampling ring to obtain volume of soil mass equal to that of sampling-ring.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

We claim
1.A soil sampler apparatus for collecting samples of soil, which comprises:
• ring-holder that is tapered to provide smooth insertion into soil, and
• sampling ring that also has a tapered edge, and places itself into the said ring-holder,
such that wall of the soil sampler causes minimum disturbance to the soil during the sampling process.
2. An apparatus of claim 1, further comprising of thin wall to offer lesser resistance during insertion in the soil.
3. An apparatus of claim 1, wherein the ring-holder stops the sampling-ring from deforming and bulging out.
4. An apparatus of claim 1, wherein the wall of the soil sampler is typically of the size of 1.5 mm or less.
5. An apparatus of claim 1, wherein a clearance of approximately 20 mm is provided between the top of the sampling-ring and the inner-surface of the ring-sampler to avoid compaction of soil during the sampling.
6. An apparatus of claim 1, further comprising of a hole on the top surface of ring-holder to allow passage of air during sampling.
7. A method of sampling soil comprising the steps of:

• inserting a sampling-ring in a ring-holder with tapered end outside;
• connecting the sampler to a sliding hammer or to a rod extension that provides a base for blows by hammer;
• giving gentle blows to the sampler unit that drives the sampling-ring into the soil;
• stopping such blows when the soil surface reaches the marking; and
• removing the sampling ring from the ring-holder to trim-off the excess soil,
such as to obtain volume of soil mass equal to that of sampling-ring.
8. A method of sampling soil as of claim 1, wherein the volume of collected soil is equal to that of volume sampling ring (V), which is calculated as - V = nr2h = 7r{l.\ cm) x5 cm = 69.27 cm3