Patent Publication Number: US-2021172839-A1

Title: Devices And Methods For Cutting And Retrieving A Sample of Wood

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is the US national stage application of International Application No. PCT/GB2019/051070, filed Apr. 15, 2019, which claims the benefit of priority from GB Application No. 1806146.5, filed Apr. 15, 2018. These prior applications are incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     This invention relates to devices and methods for cutting and retrieving a sample of wood—for example, a solid cylinder in shape, from a live tree or from cut timber. Such samples are required for use in scientific research and in laboratory analysis. Conventionally, samples are taken from trees or timber by cutting cross sections from sawn trunks using a chainsaw, which is heavy and difficult to transport, or by drilling out solid cores by hand, which is slow and laborious. 
     W09711346 (Elliott et al.) discloses a wood coring drill bit intended to be driven by a rotary power drill. JP 2017226038 (Matsuo et al.) discloses a hole saw intended to be driven by a rotary power drill. 
     BRIEF SUMMARY 
     Preferred embodiments of the present invention aim to provide generally improved devices and methods for cutting and retrieving a sample of wood. 
     According to one aspect of the present invention, there is provided a wood core sampling device comprising a metal tube having a circular cutting edge at one end, the wall thickness of the tube being arranged so that from the cutting edge the external diameter of the tube smoothly increases then decreases to form a protrusion and, at or adjacent the cutting edge, the internal diameter of the tube smoothly increases then decreases to form an expansion cavity. 
     Preferably, the end of the tube including said protrusion and the expansion cavity is carried on a removable threaded shank that in use co-operates with a thread on the metal tube. 
     Preferably, the end of the metal tube opposite to the cutting edge is threaded to cooperate in use with either a threaded plug or the threaded end of a slide hammer. 
     The threaded plug and/or slide hammer may be provided in combination with the wood core sampling device. 
     The said protrusion may be in the form of a collar, annulus or bulge. 
     In another aspect, the invention provides a method of cutting and retrieving a sample of wood by means of a wood core sampling device according to any of the preceding aspects of the invention, the method comprising the steps of driving the device into a body of wood with the cutting edge of the device leading, the device being driven by impact applied to the end of the metal tube opposite to the cutting edge; and subsequently retrieving the device from the body of wood, with the sample of wood contained within the device. 
     The step of retrieving the device from the body of wood is preferably effected by means of an extraction tool that engages the end of the metal tube opposite to the cutting-edge. 
     Preferably, said extraction tool comprises a slide hammer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: 
         FIG. 1  is a perspective view of a wood core sampling device according to one embodiment of the present invention; 
         FIG. 2  illustrates use of the sampling device: 
         FIG. 3  is a sectional view of the sampling device; 
         FIG. 4  shows the device in partial cross-section in a tree, together with a slide-hammer used to extract the device from the tree: 
         FIG. 5  is a sectional view of the cutting end of the device: and 
         FIG. 6  is a part view of a variation. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , a wood core sampling device (or sampler)  10  comprises a cylindrical metal barrel  11  having a cutting end  12  and an opposite end  14  of increased diameter which has an internal thread  16 .  FIG. 3  shows a cut core of wood  24  within the barrel  11  of the sampler  10 , and a threaded cap  18  which cooperates with the internal thread  16 . In  FIG. 2 , the sampler  10  is driven into a tree  20  by blows from a hammer  22  on the threaded cap  18  when engaged with the internal thread  16 . 
       FIG. 5  shows the cutting end  12  of the sampler  10  in more detail. The cutting edge of the end  12  is circular and of diameter E. Adjacent to the cutting edge, the wall thickness of the barrel  11  increases. The external diameter of the barrel  11  increases smoothly to J, then decreases again smoothly to H for the remainder of the length of barrel  11 . These diameter changes form a smooth circular protrusion  13 , which may be in the form of a collar, annulus or bulge, and has the effect of reducing friction between the outside of the barrel  11  and the wood as the sampler  10  is hammered into the tree, in contrast to a tubular cutter of constant diameter.  FIG. 5  also shows that as the wall thickness increases, the internal diameter of the barrel  11  close or adjacent to the cutting end  12  increases smoothly as shown at F, then decreases smoothly to G for the remainder of the length of the barrel  11 . A circular expansion cavity  15  is thus formed. This cavity allows the cut plug of wood ( 24  in  FIG. 3 ) to expand after it passes the cutting edge at end  12  and moves along the barrel  11 . The cut plug  24  is equal in length to the length of barrel  11  hammered into the tree  20  and is initially still attached to the tree. 
       FIG. 4  illustrates the extraction of the sampler  10  from a tree  20  by use of a slide hammer  30  of conventional construction. When the sampler  10  has been hammered into the tree  20  and in so doing contains the required plug sample  24 , the threaded plug  18  is unscrewed and replaced with the threaded end  32  of the slide hammer  30 . The threaded end  32  is attached to a metal rod  34  which carries at the opposite end a stop  36 . On the rod  34  is a slide bob  38 . To remove the barrel  11  and plug  24 , the slide bob  38  is manually advanced rapidly along the rod  34  to strike the stop  36 , which impact results in a force in a direction which pulls the barrel  11  out of the tree  20 . At the first impact (usually), the plug of wood  24  snaps off the tree  20 , and subsequent impacts draw the barrel  11  out completely while retaining the plug  24 . Referring now to  FIG. 3 , the sample  24  is removed by a suitable prod inserted into the cutting end  12 , and retrieved at the thick end  14 . The extracted core  24  is arranged to be of sufficient weight and length to satisfy analysis requirements, yet the tree has not been harmed or felled. 
     It has been found that a sample  24  can be taken in a few minutes. The provision of the protrusion  13  also reduces friction while the slide hammer is in use, so that the weight and length of the slide hammer parts can be of practical dimensions. 
     In contrast to prior known devices, it is not necessary to rotate the sampler  10  in use (although this can be done if desired). A regular hammer  22  can be used to drive the sampler  10  into the tree  20  (or other timber). A slide hammer  30  can be used to remove the sampler  10  with core  24 . 
     It will be understood that the edge of the cutting end  12  will become blunt with repeated use.  FIG. 6  shows a variation in which the cutting end  12  is formed on a short shank  40  that is threaded at  42 . The end of barrel  11  carries a cooperating thread  46  so that the cutting end can be replaced. This also allows barrels  11  of different lengths to be used. 
     Different lengths of sample plug will be required in different circumstances, so the barrel  11  is marked with measuring lines  19  ( FIG. 1 ). 
     In this specification, the verb “comprise” has its normal dictionary meaning, to denote non-exclusive inclusion. That is, use of the word “comprise” (or any of its derivatives) to include one feature or more, does not exclude the possibility of also including further features. The word “preferable” (or any of its derivatives) indicates one feature or more that is preferred but not essential. 
     All or any of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all or any of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. 
     Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.