US3768580A

US3768580A - Apparatus for taking an undisturbed soil sample

Info

Publication number: US3768580A
Application number: US00192234A
Authority: US
Inventors: A Mann; J Christianus
Original assignee: STICHTING WATERBOUWKUNDIG LAB
Current assignee: STICHTING WATERBOUWKUNDIG LAB; STICHTING WATERBOUWKUNDIG LABOR NL
Priority date: 1971-10-26
Filing date: 1971-10-26
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

An improved apparatus for taking an undisturbed soil sample supported by a flexible hose and an additional supporting tube which is coaxially positioned within the sampling tube proper, provided with clamping fingers for pinching off the supporting tube in the lower part of the sampling tube for keeping the sample within the supporting tube when the sampling tube is retracted from the soil, which fingers are operated by wedges when two mutually slidable parts of the sampling tube are moved by changing from pressing to pulling.

Description

[ 1 Oct. 30, 1973 United States Patent 1 Mann et al.

3,511,324 5/1970 Pieters et a1.

3,647,009 3/1972 Prelicharz......

3,621,924 11/1971 Lebourg.....

FOREIGN PATENTS OR APPLICATIONS 1 1 APPARATUS FOR TAKING AN UNDISTURBED SOIL SAMPLE Inventors: Adriaan Barend Mann; Jacobus 1,156,366 10/1963 Germany 1,177,854 9/1964 Gennany 1,208,527 1/1966 Germany Primary Examiner-David H. Brown Attorney-Ra1f I-I. Siegemund H n e a.1ne|. wmmfiw dfiMmPmm .md 6 r d ua m m .mnmhm m um e dsh n nonum. mw mn wm flh um bOfp T r m u m m mn u B Sfl M A ua t i co flm fim. mb 0. 1 w P pee m a u. a t ms OU C e e v .m ou P rS p f m mmm ].Ip S m n m w mm Awse p 42 5 2 W22 M54 7 00 1 1 32 2 5 5 l 4 5 2 7 07 1 /l 5 .4 l 2 m2 5 b u 2 I "3 2 4 H E m2 wm b 6 1 2N2 us S3 n 5 d7 l .w F

51 lm C1. 1 1

within the supporting tube when the sampling tube is retracted from the soil, which fingers are operated by wedges when two mutually slidable parts of the sampling tube are moved by changing from pressing to pulling.

5 Claims, 5 Drawing Figures PAIENTEDBBI 30 ms I 1 lllllflfl ATTORNEY5 APPARATUS FOR TAKING'AN UNDISTURBED SOIL SAMPLE In a prior art patent application Ser. No. 7,789, now U.S. Pat. No. 3,690,389, a method and an apparatus for taking an undisturbed soil sample are described, using a sampling tube with a sharp cutting mouth which is driven into the soil for taking a soil sample, the soil sample penetrating into the tube being protected against sagging by means of a pliable hose which is pulled by the sample from a hose chamber surrounding the sample tube proper, and, moreover a supporting liquid may be used for supporting the sample together with the hose. Since this support may be insufficient in at least part of the sample, an additional separate rigid supporting tube of plastic material is used which is supported coaxially within the sampling tube, which supporting tube, like the sampling tube, may be provided with extension tubes as the sampling tube is pressed into the soil. As soon as the desired depth is attained, the sampling tube is to be retracted again, and then it is to be avoided that the sample introduced into the sampling tube and its extension pieces will sink back. To that end the apparatus according to said prior patent application is provided with clamping means for pinching the lowersupporting tube, the wall thickness of this tube in the neighborhood of these clamping means being reduced for being more easily deformed. The sampling tube proper processes near its upper end a coupling member to which an extension tube may be coupled, this member and this sampling tube being provided with two sets of stops co-operating in such a manner that a given longitudinal displacement of the coupling member in respect of the sampling tube is allowed, which stops, furthermore, may transfer thrust and tensile loads from the coupling member to the sampling tubes.

Although the apparatus according to the said patent application operates, in general, very well, it has, nevertheless, some disadvantages. The clamping means used comprise a torsion sleeve which is twisted by rotating the coupling member in respect of the sampling tube, the supporting tube then being pinched off. When samples having a larger cross-section should be taken, the supporting tube is to be considerably deformed. The torsion sleeve is to be locked in the twisted condition in order to prevent the sample from sinking, but the consequence thereof is that the rotation should be restricted to about a half turn in order to ensure an unambiguous guiding of the locking lugs towards corresponding locking grooves. Said prior patent application provides a solution, but this solution is rather complicated and requires a rather complex machining of the inner surface of the sampling tube. Another disadvantage is that the reduction of the wall thickness of the supporting tube considerably reduces the longitudinal strength of this tube so that this tube may be upset by longitudinal forces which occur particularly when retracting the sampling tube, and also the radial resistance may be insufficient.

The invention provides an improvement of the latter apparatus, avoiding its disadvantages, and, more specifically, the substantial reduction of the supporting tube wall thickness then becoming superfluous.

To that end the improved apparatus according to the invention is characterized by a set of clampingfingers and a set of driving wedges co-operating therewith, one

set being connected with the coupling member, and the other one with the sampling tube, all this in such a manner that, when the coupling member is loaded by pres sure and the first set of stops of the coupling member and the sampling means are engaging one another for transmitting the thrust force, the clamping fingers remain free of the supporting tube, and, when loaded by tension, as a consequence of the ensuing longitudinal translation of the coupling member in respect of the sampling tube, the bevelled surfaces of the wedges will drive the fingers inwards in order to pinch off the supporting tube until the second set of stops of the coupling member and the sampling tube engage one antt her.

In particular a clamping sleeve is used having slots in which the clamping fingers are hingedly mounted, a corresponding number of wedges being slidable in respect of this sleeve and being partially inserted into these slots, which sleeve is provided with a stop shoulder which may abut a shoulder of the sampling tube or of the coupling member as the case may be for transferring tensile forces, the extremities of the wedges also abutting this shoulder, and the end of the sleeve remote from the stop shoulder serving for transferring thrust forces.

These clamping fingers are capable of pinching off the supporting tube effectively, but the passage between the supporting tube and the sampling tube used for supplying the additional supporting liquid cannot be obstructed thereby, as is the case with the torsion sleeve according to the prior patent application. In order to prevent the loss of supporting liquid when retaracting the sample tube, a coupling socket is used surrounding the supporting tube and its first extension near the intermediate joint, and in the inner surface of the coupling member and near its upper edge a sealing ring is provided, the coupling sleeve sealingly fitting in this sealing ring, which sleeve, in the pressing position of the sampling tube, is situated above the sealing ring so that the passage remains open, but on shifting the coupling member in respect of the sampling tube when changing towards the pulling position this sleeve will engage the sealing ring in order to close the liquid passage completely.

In this manner an improved apparatus is obtained, in which the sample is simply pinched off when changing to pullingthe sampling tube after pressing without the necessity of rotating the tube inserted in the soil.

The invention will now be elucidated by reference to the drawings showing in:

FIG. 1, a front view, partially in section along the line 1-1 of FIG. 2, of a preferred embodiment of a clamping sleeve for the apparatus according to the invention;

FIG. 2, an end view of this clamping sleeve, partially in cross-section along the line 11-11 of FIG. 1;

FIGS. 3 and 4, partial sections of the clamping sleeve of FIGS. 1 and 2 with associated parts and adjacent portions of a sampling tube and a supporting tube in two different positions; and

FIG. 5, a partial section ofa coupling member joining a similar clamping sleeve and a coupling socket for the supporting tube and an extension tube therefor.

The apparatus according to the invention mainly corresponds with the apparatus according to the prior patent application. Corresponding parts have been indicated with the same reference numerals as in this prior application.

In the apparatus according to the invention, as appears from FIGS. 3 and 4, a coupling sleeve 50 which is separately shown in FIGS. 1 and 2 is situated within the upper end of the sampling tube proper 1 and in the coupling member 3.

Elements

1, 3 and 50 are coaxial to each other and concentric to supporting tube 18, being inside of the former elements. The inner diameter of this sleeve is substantially equal to that of the coupling member 3, so that the supporting tube 18 fits therein with some clearance which is sufficient for letting pass the supporting liquid as described in the prior patent application. The thickness of the wall of the sup' porting tube 18 may be somewhat reduced in the vicinity of the sleeve 50 as indicated at 34, but this reduction may be smaller than in the supporting tube according to said prior application.

The sleeve 50 is, at its upper end, externally threaded at 51 for connecting this sleeve to the coupling member 3. Therefor, sleeve 50 can be interpreted as an extension of member 3 (or vice versa). The lower part 52 has a larger external diameter, and joins the upper part by means of a shoulder 53. In this lower part a number of slots 54 is provided extending, near the shoulder 53, up to the outer diameter of the upper part, but penetrating the whole wall further downwards, so that a shoulder 55 is formed. In each slot 54 a curved finger 56 is present which is provided with a pivot pin 57 projecting at both sides from the finger 56 and fitting in a corresponding recess 58 of the slot 54 in question, so that the finger 56 is hingedly supported in this slot but may be easily inserted in and removed from this slot. Instead of recesses a groove with a corresponding depth may be used, extending along the whole circumference of the lower part 54 and being machined or milled in this part.

The sleeve 50 which is fixedly connected to the coupling member 3 is slidable in respect of the sampling tube 1. This sliding movement is limited to a given value, e.g. about mm, by an inward collar 59 of the sampling tube 1. When the sampling tube is pressed into the soil, the upper face of this collar 59 abuts the lower face of the coupling member 3 as shown in FIG. 3, and when the sampling tube is pulled from the soil the lower face of the collar 59 abuts the upper face of the shoulder 53 of the sleeve 50, as shown in FIG. 4. In this manner, the lower end face of coupling member 3 and the upper end face of collar 59 define a first set of stops which engage when member 3 is urged down and against the sampling tube. The several upper end faces 53 and the lower end face of collar 59 define a second set of stops engaging when member 3 is pulled up. The axial distance of the lower end face of member 3 and of shoulders 53 in relation to the axial dimension of collar 59 defines the range of mutual displacement of member 3 and of sampling tube 1. In this manner thrust and tensile forces of the extension tubes which are connected to the coupling member 3 are transferred to the sampling tube 1 but in different axial dispositions of these parts to each other.

As appears from FIGS. 3 and 4, a number of driving wedges 60 is arranged between the sampling tube 1 and the clamping sleeve 50, each wedge corresponding with a clamping finger 56. These driving wedges are each slidable in corresponding slot 54, and are each provided with a shoulder 61 abutting, in the pressing position, the shoulder 55 of the slot in question. The upper face 62 of each wedge 60 abuts the lower face of the collar 59 of the sampling tube 1. Moreover each wedge 60 has a curved surface 63, the curvature of which being adapted to the outer curvature of the clamping finger in question.

As clearly appears from FIG. 4, the coupling member 3 and the sleeve 50 connected thereto will be pulled upwards and be shifted in respect of the sampling tube as soon as the operation is changed to pulling, the fingers 56 then being taken along but the wedges 60 being held back by the collar 59. Thus the fingers 56 are driven inwards by the wedges 60 in question so that the wall portion 34 of the supporting tube 8 is deformed inwardly and is crushed. In practice it has appeared that with eight fingers a sufficient compression of the supporting tube may be obtained for holding back the sample when the sampling tube is pulled upwards.

The fingers 56 and also the wedges 60 may be manufactured in a simple manner from a metal cylinder which may be easily machined on a lathe, and from which a number of fingers or wedges respectively may be obtained by sawing or milling.

It will be clear that other embodiments are possible as well, in which the wedges 60 are pulled along with the coupling member 3, the fingers 56 then remaining stationary in respect of the sampling tubes, in which case a similar operation is obtained.

The fingers 56 provide, as mentioned before, an effective pinching of the supporting tube 18 for holding back the sample contained therein. It has appeared to be possible to reduce the wall thickness of the tube 18 considerably less than was necessary in the embodiment according to the said prior patent, so that the supporting tube becomes stronger and will withstand axial pressure forces better. The liquid passage between the supporting tube 18 and the sampling tube 1 or their extension pieces will, however, not be closed then. If this liquid passage is not closed the supporting liquid in this passage, when retracting the sampling tube, will continue to be acting on the hose portion leaving the hose chamber contained in the wall of the sampling tube 1. Thus, during retracting, the hose will be extracted from the chamber and, thereby, becomes unfit for further use.

This may be avoided in the manner shown in FIG. 5 by providing in the inner wall of the coupling member 3 and near its upper end a sealing ring 64, and by making the supporting tube so long that the latter, in the pressing position shown (see FIG. 3), extends above the coupling socket 65, for instance in the form of a steel ring, is provided surrounding the supporting tube more or less tightly, and, at the same time, serving to hold the extension tube 18. In the pressing position shown this coupling socket 65 is positioned completely above the coupling member 3. The outer diameter of this socket is such that the latter will tightly fit in the sealing ring 64. When the operation is changed to pulling, the coupling member 3 is shifted in respect of the supporting tube 18 by a distance which is determined by the distance between the shoulder 53 and the lower end face of the coupling member 3, as appears from FIG. 4. The mutual position of the sealing ring 64 and the socket 65 is chosen so that the socket 65 after being shifted will be situated inside the ring 64, so that the liquid passage is completely closed and the discharge of the supporting liquid is avoided.

In this manner a considerable simplification is obtained, and, particularly in the case of samples with a large cross-section, a very efficient pinching becomes possible. A special advantage is that it is no longer necessary to rotate the tube assembly before extracting the same.

We claim:

1. In an apparatus for taking an undisturbed soil sample and which includes a sampling tube with a sharp cutting mouth and a supporting tube inside of the sampling tube with some clearance in-between, the improvement comprising:

a coupling member disposed above the sampling tube coaxially thereto and concentric about the supporting tube, said coupling member and sampling tube being provided with two sets of stops, the stops of each set cooperating in such a manner that a given axial translation of the coupling member in respect of the sampling tube is allowed, said first and second stops respectively for transmitting downwardly directed thrust and upwardly directed tensile loads respectively from the coupling member to the sampling tube;

a set of clamping fingers and a set of cooperating wedges, respectively with bevelled surfaces, one set being connected to the coupling member and the other one to the sampling tube, so that the relative axial position of the fingers and of the wedges is translated into different radial positions of the tingers and in such a position relation to each other that, when the coupling member is loaded by pressure and the first set of stops of the coupling member and the sampling tube are engaging one another for transmitting thrust force from the coupling member to the sampling tube and the clamping fingers remain free of the supporting tube; upon pulling said coupling member, the coupling member being displaced axially relative to the sampling tube until the second set of stops engage one another, whereby the bevelled surfaces of the wedges drives the fingers inwards in order to pinch off the supporting tube.

2. Apparatus according to claim 1, characterized an extension of and above the supporting tube and coaxial therewith a coupling socket surrounding the supporting tube and said extension near the intermediate joint, and by a sealing ring in the inner surface of the coupling member and near its upper edge, the coupling socket sealingly fitting in this sealing ring, which sleeve, in the pressing position, is situated above the sealing ring so that on shifting towards the pulling position this socket will engage the sealing ring.

3. Apparatus according to claim 2, characterized in that the socket is a separate steel ring tightly fitting in the supporting tube and its extension tube.

4. Apparatus according to claim 1, and including a clamping sleeve having axial slots distributed about the axis, the clamping fingers being hingedly mounted in the slot, a corresponding number of wedges being slidable in respect of this sleeve and being partially inserted into these slots, said sleeve being provided with a shoulder as one of the stops of said sets of stops.

5. Apparatus according to claim 4, characterized in that the fingers and wedges are each machined or sawed from a cylindrical body.

Claims

1. In an apparatus for taking an undisturbed soil sample and which includes a sampling tube with a sharp cutting mouth and a supporting tube inside of the sampling tube with some clearance in-between, the improvement comprising: a coupling member disposed above the sampling tube coaxially thereto and concentric about the supporting tube, said coupling member and sampling tube being provided with two sets of stops, the stops of each set cooperating in such a manner that a given axial translation of the coupling member in respect of the sampling tube is allowed, Said first and second stops respectively for transmitting downwardly directed thrust and upwardly directed tensile loads respectively from the coupling member to the sampling tube; a set of clamping fingers and a set of cooperating wedges, respectively with bevelled surfaces, one set being connected to the coupling member and the other one to the sampling tube, so that the relative axial position of the fingers and of the wedges is translated into different radial positions of the fingers and in such a position relation to each other that, when the coupling member is loaded by pressure and the first set of stops of the coupling member and the sampling tube are engaging one another for transmitting thrust force from the coupling member to the sampling tube and the clamping fingers remain free of the supporting tube; upon pulling said coupling member, the coupling member being displaced axially relative to the sampling tube until the second set of stops engage one another, whereby the bevelled surfaces of the wedges drives the fingers inwards in order to pinch off the supporting tube.