WO1984001827A1

WO1984001827A1 - A boring instrument for removing a sample core

Info

Publication number: WO1984001827A1
Application number: PCT/SE1982/000348
Authority: WO
Inventors: John Koskiniemi
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-04-24
Filing date: 1982-10-25
Publication date: 1984-05-10
Anticipated expiration: 1985-04-25
Also published as: SE8102670L; SE444082B; EP0122912A1

Abstract

Sample-boring instrument which is easy to use even in confined spaces and with which a detached bored core can be handled with such a high degreee of care that is is not disorientated or contaminated by mechanical action or contact with foreign matter. According to the invention, the sample-boring instrument consists of a tubular boring body (1), one end section of which is made with a cutting edge (5) extending round the end surface of the tube, and a centring and ejecting rod (2) which is movably guided inside the tube, the terminal positions of which are chosen so that the end of the rod located nearest to the cutting edge can be moved from a position in which it is retracted inside the tube into an outer position in which the said end is located outside the cutting edge.

Description

A Boring Instrument for removing a Sample Core

The present invention relates to a boring instrument for removing a sample core. The sample-boring instrument is preferably intended to be used, for example, for checking the growth of timber, for monitoring impregnation, for determining moisture levels, for taking samples of dry rot, for taking samples of mould, for monitoring the depth of rot damage, for determining the quality of timber or assessing the core of wood, but the instrument may more generally be used for porous materials whenever it is desired to obtain a bored core of varying length.

Instruments known previously, such as growth bores, for example, cannot be used in connection with finished timber material without causing damage to the material which is located adjacent to the bore-hole. Moreover, it is often very difficult to set up existing instruments and to hold them when access is difficult and the space confined. Moreover, it is difficult to set up the instrument very accurately in a precise specific position. Furthermore, bored cores which have been removed fall apart very easily, with the ris of disorientation of their sections, which can give rise to totally false results from special analyses of the bored cores. A widespread effort to find the answer to a vast number of questions relating to timber construction, moisture conditions, quality characteristics, attack by rot, attack by mould, etc., chemical impregnation and so on has led to demands for a purpose-built instrument for taking samples which is easy to use and is suited to different conditions.

The main object of the invention is to provide an instrument of the kind described above which is easy to use and with which it is possible to remove in an expedient way slender, long and coherent bored cores from timber and other material and to transfer this bored core from the instrument without touching it, for example, to a sealed container, so that the removed core can afterwards be analysed without contamination, and with which a large number of samples can be taken in a rationalised way in a short period of time.

This object is achieved with a sample-boring instrument constructed according to the invention, which is primarily characterised in that it consists both of a tubular boring body, one end section of which is formed with a cutting edge extending round the end of the tube, and also of a centring and ejecting rod which is movably guided inside the tube, the terminal positions of this rod being chosen so that the end of the rod located nearest to the cutting edge can be displaced from a position wherein it is retracted inside the tube into an outer position in which the said end is located outside the cutting edge.

A sample-boring instrument constructed according to the invention may conceivably be used, for example, in various research institutes, monitoring organisations, in the impregnation industry, in the cabinet-making industry or other timber-related industries, by electricity distributors for checking pole-lines, by re-impregnation firms, by saw-mills, by protection firms, for example, in connection with windows and by forestry companies, amongst others.

An embodiment example of the subject of the invention is described in the following, with reference to the accompanying drawings, on which Figure 1 is a longitudinal section through a sampleboring instrument for wood,

Figure 2 is a side view of a part appertaining to the sample-boring instrument shown in Figure 1,

Figure 3 is a perspective view of the cutting part of the sample-boring instrument, shown on a larger scale,

Figure 3a is a longitudinal section through a portion of the cutting edge on the part shown in Figure 3,

Figure 3b is a longitudinal section through another portion of the cutting edge on the same part, Figure 4 is a side view of the part shown in Figure 3, Figure 5 is a partially-sectioned perspective view of the instrument, wherein the parts appertaining to the instru ment are shown in the same relative position as in Figure 1,

Figure 6 is a partially-sectioned perspective view of the instrument while it is being set up against the object out of which a sample is to be bored,

Figure 7 is a perspective view of the instrument during the first phase of being driven into the object from which a sample is to be bored, Figure 8 is a partially-sectioned perspective view of the same instrument after it has been removed from the said object from which a sample is to be bored,

Figure 9 is an end view of the cutting part of the tool,

Figure 9a is a longitudinal section showing the cutting angle at a section of the cutting edge of the tool,

Figure 9b shows the angle of the cutting edge at anothe section of the cutting edge of the tool,

Figure 10 shows the cutting edge line of the tool, developed, Figure 11 is a Table giving an example of how the cutting edge curve of the tool can be developed.

The instrument shown on the Drawing consists of three main parts, the first of these being a boring tube which is designated 1 as a whole, the second being a centring and ejecting rod which is designated 2 as a whole and the third being a supporting sleeve which is designated 3 as a whole. The boring tube 1 is preferably thin-walled. A suitable material thickness may be approximately 0.5 mm with an external diameter of approximately 9 mm. At the front, i.e. on the left in the Drawings, the boring tube has a thicker section which is formed by a gradual reduction of the internal diameter of the tube towards the front, and a gradual increase in the external diameter. The end edge 5 of the tube is ground to an undulating shape which is shown most clearly in Figures 3 and 4, with an outwards-facing bevelled surface 6, 7. Due to the acute angles α, β formed with the internal wall of the tube, the bevelled surface 6, 7 forms a cutting edge extending over the circumference of the tube, in the form of two wave-tops 8, 9 with two wave-valleys 10, 11 located between them. The wave-top 8 is somewhat higher than the wave-top 9. Tbe cutting angle α at the wave-top 8 and the parts adjoining it, i.e. the parts of the circumference which extend downwards to the wave-valleys 10, 11, is preferably acute, as is clearly shown in Figures 3b and 9b. The angle of the cutting edge is preferably between 25° and 35°. A suitable angle for the cutting edge has been found to be approximately 28°. The cutting edge angle at the wave-top 9 and the sections adjoining it, i.e. the sections which extend downwards into the wave-valleys 10, 11, are slightly blunter than the former angle, as can be seen in Figures 3a and 9a. This cutting edge angle expediently lies somewhere between 40° and 50°. However, a suitable cutting edge angle has been found to be approximately 45°. When the boring tube is forced into the material from which a sample is to be taken, the higher wave-top 8 and the adjoining parts of the cutting edge carry out a cutting process where no shaving are detached, at the same time as compression of the material occurs in an outwardly direction. The lower wave-top 9 and the adjoining parts of the cutting edge serve mainly for compressing the material. The material is compressed both in an outwardly direction and in an inwardly direction. The blunter the cutting edge angle β , the greater is the amount of material compressed inwards, and vice versa. Towards the rear the boring tube has a thicker section 12 which has the same internal diameter as the rest of the tube, and which is cylindrical on the outside. The boring tube is mounted via the rear thicker section 12 so that it can be displaced in a supporting sleeve 13, the internal diam r of which exceeds the external diameter of the rear thicker section 12 of the boring tube by an amount sufficient to give a sliding fit. At the rear a pin-shaped part 14 is welded to the supporting tube 13, for use as a chuck fitment when a drilling machine is used to rotate the instrument, for example. The centring and ejecting rod 2 is mounted displaceably in the boring tube. The ejecting rod has a front section 15, an intermediate section 16 and a rear sec tion 17. The intermediate section 16 has an external diameter which is sufficiently less than the internal diameter of the boring tube 1 to give a sliding fit, while its front end section 15 has an external diameter which is less than the internal diameter of the boring tube by a slight amount of play, and its rear end section 17 has an external diameter which corresponds approximately to the internal diameter of the supporting sleeve 13. The rear section of the rod 2 is locked into the supporting sleeve by means of a locking screw 18 screwed into the supporting sleeve. At the front the rod 2 is formed with a centrally disposed con ical pin 19 which continues at its base into a concave surface on the front end of the rod. At the front, the transi tion between the sections 17 and 16 of the rod 2 forms a forwards-facing shoulder 20 and at the rear the thicker section 12 of the boring tube forms a backwards-facing shoulder 21. Between the two shoulders 20 and 21 a compression spring 22 is hraced. In the supporting sleeve 3 there is a slit 23 extending longitudinally along it, having at the front an end section 23a which is angled counter to the direction of rotation. The supporting sleeve is surrounded by a running sleeve 24, the internal diameter of which corresponds to the external diameter of the supporting sleeve, with a sliding fit. By means of a transverse entrainment screw 25 which is screwed into the running sleeve 24 and preferably also into the thickened section 12 of the boring tube the running sleeve 24 is connected to the boring tube via the slit 23 in the supporting sleeve. The entrainment screw 25 is held in its screwed-in position by means of a stop screw 26 which is screwed in from the front end of the running sleeve 24. The running sleeve is also surrounded by a gripping sleeve 27 which consists of a front half 27a and a rear half 27b. The ends of the running sleeve 24 form a forwards-facing and a backwards-facing shoulder which co-act respectively with corresponding backwardsfacing and forwards-facing shoulders on the front and rear halves of the gripping sleeve respectively. The two halves of the gripping sleeve are expediently connected to each other by means of a longitudinal screw connection. The internal diameter of the gripping sleeve is adapted so that it can be rotated easily on the running sleeve 24.

This construction means that the running sleeve 24, the supporting sleeve 3 and the boring tube 1 are connected to each other rotationally fixed via the entrainment screw 25. The running sleeve 24 and the boring tube 1 are also connected immovably to each other via the entrainment screw 25, while they can be displaced in the longitudinal direction relative to the supporting sleeve 3 due to the fact that the entrainment screw 25 can move along the slit 23. The rotational force which is transmitted from a drive source such as a mechanical drill, for example, to the supporting sleeve 3 is transmitted further via the entrainment screw 25 to the boring tube due to the fact that the entrainment screw 25 rests against the sides of the slit 23. The gripping sleeve 27 is not axially displaceable relative to the running sleeve 24, due to the mutual abutment effect between them but on the other hand it can rotate relative to the running sleeve 24. When the supporting sleeve 3 rotates the gripping sleeve 27 can be held by the operator in one hand and guided in the longitudinal direction of the supporting sleeve provided that the entrainment screw is not located in the laterally-angled end section 23a of the slit. When the supporting sleeve is not being rotated the gripping sleeve 27 can be moved in its longitudinal direction irrespective of the displacement position in which the entrainment screw 25, which acts as an entrainment pin, is located. The compression spring 23 strives to move from the boring sleeve into the position shown in Figure 1 in which the centring and ejecting rod 2 is located in its rear position, fully retracted into the boring tube. To ensure that there is a good grip on the gripping sleeve 27, this may be provided with a gripping surface on the outside.

As stated above, the instrument can be used expediently connected into the chuck of a mechanical drill or a drilling brace (not shown on the Drawings) by fixing the pin 14 in the chuck. The tool is set up against the object 28 from which a sample is to be bored, after the boring tube has been pulled backwards relative to the centring rod 2, against the effect of the spring 22, by moving the gripping sleeve 27 in the direction of the mechanical drill so that the end section of the centring rod 2 projects slightly beyond the cutting edge 8 of the boring tube. While the mechanical drill and thus also the centring rod 2 are pressed transversely against the workpiece, the gripping sleeve 27 is moved forwards, this movement being enhanced by or effected entirely by pressure from the spring 22. This phase, in which the boring tube penetrates into the workpiece, is shown in Figure 7. The strength of the spring 22 is preferably adapted so that it is able to force the boring tube in to a depth of a few millimetres on its own, after which the boring tube is driven in further while the centring rod is held resting transversely against the workpiece, by moving the gripping sleeve 27 forwards manually, the spring 22 providing additional force to aid this movement. The cutting edge of the boring tube thus displaces freed material to the bored core and the surrounding material by compression. When a bore depth of preferably 5 - 15 mm has been attained with the aid of the pressure from the spring 22, the drive source is pulled back with the supporting sleeve 3, while the gripping sleeve 27 is held transversely, until the entrainment pin 25 has reached the angled end section 23a of the slit 23 and is snapped into it due to rotation of the supporting sleeve. After this, boring can be continued until the desired depth is reached, simply by forwards pressure from the drive source. When the desired depth has been reached, the instrument is pulled out of the object 28 with the aid of the drive source while rotation continues, after which the drive source is stopped. The bored core can thereafter be removed from the boring tube by moving the gripping sleeve 27, and with it also the boring tube, backwards relative to the supporting sleeve 3. The ejecting rod 2 thereby pushes the bored core out of the boring tube 1.

In order to make boring and the release of the bored core easier when the boring tube of the boring instrument has a small diameter, the boring tube can expediently be provided with a longitudinal slit terminating with its outlet at the cutting edge, thereby protecting the bored core from any high level of friction and from diorientation of its sections.

The instrument shown on the Drawings is primarily designed to be used for free-hand drilling, but it can of course also be clamped in a holder, for example. The released bored core can be transferred to a closed or open vessel without manual or mechanical contact which might involve contamination of the material or disorientation of its various sections. Due to the centrally positioned centring point 19, very exact positioning of the cutting edge is obtained relative to the object from which a sample is to be taken. With the tool a circular cutter is obtained which does not create shavings, and the movement of which is very reliably determined by the centring rod so that the risk of chopping at the point of the bore and damage to the surround ing surface and material is eliminated, which means that it is possible to work much nearer glass and metal, etc. The construction described above enables boring tube ends with a saw-toothed or milled cutting edge to be used as well. Optionally, the point of the boring tube can be made with a section such that the effective parts can be replaced or the point of the boring tube extended. If the compression spring 22 is replaced with some other elastic/expanding material it is possible to vary the length of the bored core even more, with one and the same centring rod in one and the same supporting sleeve. When taking bored wood samples a long way from the drive source or in confined spaces the boring point can be attached to a flexible shaft which contains another flexible shaft which functions as the centring and ejecting rod. A suitable length for the centring point 19 is approximately 2 mm.

In Figure 9 the point of the boring tube is divided up by a number of lines a-11. In Figure 10 the cutting edge curvature is shown, and this can also be read off in the Table shown in Figure 11. Figure 9b shows the acute cutting edge angle α which applies within the range a-q in Figure 10, while Figure 9a shows the blunter cutting edg angle β , which applies within the range q-a in Figure 10. The extent of the two respective cutting edge angles is also marked with arcs of a circle in Figure 9.

The invention is not restricted to the embodiment which is described above and shown on the Drawings purely by way of example, but its details can be modified within the frame work of the following Patent Claims without thereby exceeding the scope of the basic concept of the invention. In order to make it easier to push the boring tube into the object involved it can be provided with a screw thread on the outside, near the cutting edge.

Claims

P a t e n t C l a i m s

1. A boring instrument for removing a sample core, characterised in that it consists of a tubular boring body (1), one end section of which is formed with a cutting edge (5) extending round the edge of the tube, and a centring and ejecting rod (2) which is movably guided inside the tube, the terminal positions of this rod being chosen so that the end of the rod located nearest to the cutting edge can be displaced from a position wherein it is retracted into the tube (Figures 1, 5) into an outer position (Figure 6) in which the said end is located outside the cutting edge.

2. A sample-boring instrument according to Patent Claim 1 characterised in that the outside surface of the section of the boring tube (1) which is located nearest the cutting edge (5) has a diameter which reduces from the cutting edge, and the inside surface has a diameter which increases from the cutting edge.

3. A sample-boring instrument according to Patent Claim 1 or 2, characterised in that the cutting edge is wave-shaped, considered in the circumferential direction.

4. A sample-boring instrument according to Patent Claim 3, characterised in that the cutting edge (5) forms at least two wave-tops (8, 9) with wave-valleys (10, 11) lying between them, one wave-top (8) being higher than the other (9), the cutting edge being formed at the transition between an outwardly-facing bevel (6, 7) and the interior of the tube (1).

5. A sample-boring instrument according-toPatent Claim 4, characterised in that the higher wave-top (8), which forms the cutting part of the cutting edge, has a cutting edge angle of 25° - 35°, and preferably approximately 28°, and the lower wave-top, which forms the part of the cutting edge which compresses the material, has a blunter angle of 40° -50°, and preferably approximately 45°.

6. A sample-boring instrument according to any of the preceding Patent Claims, characterised in that the centring and ejecting rod (2) is spring-loaded towards the position in which it is retracted into the boring tube.

7. A sample-boring instrument according to Patent Claim 6 characterised in that the boring tube (1) is axially movable in, and rotationally fixed relative to, a rotatable support ing sleeve (3) which surrounds it.

8. A sample-boring instrument according to Patent Claim 7, characterised in that the supporting tube (3) has a running sleeve (24) engaged round it which is connected to the boring tube (1) by means of a radially-extending entrainment pin (25) via a longitudinally extending running slit (23) in the supporting tube, the ends of the slit forming terminal stops for the mutual displacement movements of the boring tube (1) and the ejecting rod (2), and its side walls forming a stop for the entrainment pin (25) so that the supporting tube causes both the boring tube (1) and the running sleeve (24) to rotate when it is set in rotation by means of a suitable drive source.

9. A sample-boring instrument according to Patent Claim 8, characterised in that a compression spring (22) is accommodated in the supporting tube (3) and rests via one of its ends against a stop (20) on the centring and ejecting rod (2) and via its other end against a stop (21) on the boring tube (1).

10. A sample-boring instrument according to Patent Claim 8 or 9, characterised in that the section (23a) of the slit (23) in the supporting sleeve which is located nearest the cutting edge is angled counter to the direction of rotation so that the entrainment pin can be allowed to fall into this angled section when it reaches this displacement position as the supporting sleeve (3), and with it the boring tube (1), is being moved.

11. A sample-boring instrument according to any of Patent Claims 8 - 10, characterised in that the running sleeve (24) has a gripping sleeve (27) engaged round it, rotationally fixed and axially immovable relative to the former.