Core Saw TECHNICAL FIELD [0001] The invention relates to a core saw for cutting cylindrical core samples longitudinally into two sections BACKGROUND ART [0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application. [0003] Core samples are typically obtained from a medium for testing or analysis thereof. The medium may comprise an underground formation, and core samples may be obtained for geological testing and analysis of sections of the underground formation. [0004] Core saws are used to cut cylindrical core samples longitudinally into two halves for subsequent testing or analysis of the core sample. Typically, one half is subjected to testing or analysis, and the other half is retained for reference purposes. [0005] One known type of core saw comprises a feed trough along which spaced feed pins are adapted to advance to convey core holders carrying core samples to a cutter which typically comprises a circular saw blade. The feed pins are spaced at intervals dimensioned to accommodate individual core holders therebetween. The feed pins extend through a slot formed in the bottom of the trough and are carried on an endless feed chain disposed below the trough. The feed chain passes around end sprockets, at least one of which is a drive sprocket adapted to be driven by a drive motor. With this arrangement, the feed pins are conveyed around an endless path, a run of which passes along the trough to convey core holders inserted between the feed pins to the circular saw blade. The circular saw blade is driven by an electric saw blade motor. [0006] The core saw incorporates a control system for controlling operation of the feed chain drive motor and the saw blade motor, regulating the speed at which the feed pins convey the core holders towards the circular saw blade and also regulating the rotational speed of the saw blade. As the hardness of the core samples can vary, there is a need to relate the rate at which the core holders are fed to the saw blade to the rotational speed of the saw blade. Further, there is a need for provision to terminate operation of the core saw if a maximum allowable cutting pressure is exceeded or if jamming occurs. [0007] While such a core saw has proved to be commercially successful, it does have several disadvantages. [0008] One disadvantage relates to a potential safety issue. In operation of the core saw, the saw operator is required to insert core holders with core samples held therein into the spaces between successive feed pins. This requires care, as there is potential for injury, with the fingers of the operator being caught by the feed pins. [0009] The arrangement also has the disadvantage that the rate at which the core holders are delivered to the saw blade is governed entirely by the rate at which the feed pins are advanced along the feed trough. [0010] Further, the operator is not able to manually retract a core holder within the feed trough, as the core holder is constrained by the feed pins between which it is disposed. [0011] It is against this background that the present invention has been developed. SUMMARY OF INVENTION [0012] According to a first aspect of the invention there is provided a core saw comprising a cutter, and conveyer means for receiving and conveying a core holder to the cutter for cutting of a core sample held in the core holder, the conveyor means comprising drive means defining a movable section adapted to selectively receive a portion of the core holder to provide engagement between the movable section and the core holder for conveying the core holder to the cutter, the drive means comprising an endless loop defining said movable section, wherein the endless loop has openings therein and wherein said portion of the core holder is receivable in one or more of the openings to provide said engagement between the endless loop and the core holder. [0013] Preferably, the conveyer means further comprises a base for receiving and slidably supporting the core holder for movement towards the cutter [0014] Preferably, the drive means is associated with the base to permit said engagement between the movable section and the core holder while the core holder is supported on the base.
[0015] Preferably, the base presents a low-friction surface for slidingly supporting the the core holder for movement therealong. [0016] Preferably, the base comprises a longitudinal opening through which said portion of the core holder can extend for engagement with the movable section. [0017] Preferably, the base comprises two tracks in spaced apart relation with the longitudinal opening therebetween. [0018] Preferably, each track is defined by an elongate element. [0019] Preferably, the elongate elements are formed of a low-friction material to present low-friction surface for slidingly supporting the core holder on the base. The strips may be formed of any appropriate material, examples of which include ultra-high molecular density plastic or stainless steel. [0020] Preferably, the conveyer means further comprises guide for guiding movement of the core holder along the base. [0021] Preferably, the guide comprises two guide portions on opposed sides of the base, whereby the core holder is receivable between the guide portions for guided movement therebetween. [0022] Preferably, the drive means comprises a cyclically movable structure defining the endless loop. [0023] Preferably the endless loop is configured for movement about two end rollers and defines a section extending between the two rollers, said section extending between the two rollers defining the movable section. [0024] Preferably, the endless loop has an upper run and a lower run each extending between the two end rollers, the upper run defining said section extending between the two rollers. [0025] Preferably, the endless loop comprises openings, wherein said portion of the core holder is receivable in one or more of the openings to provide engagement between the endless loop and the core holder for conveying the core holder to the cutter. [0026] Preferably, the endless loop comprises a roller chain. With this arrangement, the end rollers are configured as chain sprockets.
[0027] Preferably, the roller chain comprises a duplex roller chain having two chain parts in side-by-side relation. [0028] With the arrangement in which the endless loop comprises a roller chain, the chain comprises a plurality of chain links which define the openings in the endless loop, wherein said portion of the core holder is receivable in one or more of the openings to provide engagement between the roller chain and the core holder for conveying the core holder to the cutter. [0029] Preferably, the core holder comprises a body having a base, wherein said portion depends from the base. [0030] Preferably, said portion of the core holder comprises at least one drive lug. [0031] Where the roller chain comprises a duplex chain, said portion of the core holder, said portion of the core holder preferably comprises two drive lugs, each engagable with a respective one of the chain parts. . [0032] Preferably, said portion of the core holder is located at one end of the core holder. Preferably, said one end is a trailing end of the core holder with respect to the direction of movement of the core holder towards the cutter. [0033] Preferably, the core saw may comprise a body defining a work surface in which there is provided a trough to receive the core holder, the trough extending to the cutter and having a bottom defining the base for receiving and slidably supporting the core holder for movement towards the cutter. [0034] Preferably, the trough is of a length capable of receiving a plurality of core holders in end to end relation. [0035] Preferably, the trough is dimensioned such that a core holder received therein is accessible by a saw operator. Preferably, the trough is of a depth such that an upper portion of the core holder is accessible when the core holder is received in the trough. With this arrangement, the saw operator is able to conveniently insert the core holder into the trough and is also able, if necessary, to lift the core holder out of the trough. Further, the saw operator is also able to grasp a core holder which is in the trough, lift it out of engagement with the drive means and manually move the core holder along the trough before releasing it to return into engagement with the drive means. This is advantageous in circumstances where the saw operator may wish to advance the core holder towards the cutter at a rate faster than that at which it is able to be conveyed by the drive means. Additionally, the saw operator is also able to grasp a core holder which is in the trough and manually retract it along the trough away from the cutter. This is advantageous if the saw operator wishes to interrupt or terminate cutting of a core sample being held in the core holder. A circumstance in which this might arise is where the cutter is overloaded or jammed while performing a cutting action on the core sample. [0036] According to a second aspect of the invention there is provided a core holder for use with a core saw according to the first aspect of the invnetion, the core holder comprising a body adapted to receive and support a core sample for cutting thereof, the body having a base and a portion depending from the base, said portion being configured for said engagement with the movable section of the core saw [0037] According to a third aspect of the invention there is provided a core holder comprising a body adapted to receive and support a core sample for cutting thereof, the body having a base and a portion depending from the base for engagement with a movable section having openings therein for conveyance of the core holder to a cutter, wherein said portion is configured to be receivable in one or more of the openings to provide said engagement between the movable section and the core holder. [0038] Preferably, said portion further comprises at least one drive lug for engagement with the movable section. [0039] Preferably, the at least one drive lug is adapted to be received in openings in the movable section. [0040] Preferably, there are two drive lugs. [0041] Preferably, at least one drive lug is located at one end of the core holder. Preferably, said one end is a trailing end of the core holder with respect to the direction of movement of the core holder towards the cutter [0042] Preferablythe movable section is defined by a roller chain, wherein the at least one drive lug is adapted to be received in openings in the roller chain. [0043] The roller chain may comprise a duplex chain having two chain parts in side-by side relation, in which case the two drive lugs may each be engagable with a respective one of the chain parts.
[0044] Preferably, the body comprises a base, two ends, and a cradle supported on the base and extending between the two ends, the two ends and the cradle being configured to define a central slot along which a cutter blade can pass to cut a core sample supported in the cradle into two longitudinal sections, wherein the at least one drive lug depends from the base. [0045] Preferably, the at least one drive lug depends from the base at or adjacent one end of the body. [0046] According to a fourth aspect of the invention there is provided a method of cutting a core sample into two longitudinal sections using a core saw according to the first aspect of the invention. [0047] Preferably, the method further comprises supporting the core sample in a core holder according to a second aspect of the invention. [0048] Preferably, the method further comprises positioning the core holder with the core sample supported therein on the conveyor means in engagement with the drive means. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which: Figure 1 is a perspective view of an embodiment of a core saw according to the invention; Figure 2 is a further perspective view of the core saw depicting a protective shroud in a raised condition to provide access to a cutter blade; Figure 3 is a schematic perspective view of a core holder which is used to support a core sample to be cut by the core saw; Figure 4 is a side view of the core saw; Figure 5 is a plan view of the core saw; Figure 6 is an end view of the core saw; Figure 7 is a perspective view of the core saw viewed from one end thereof; Figure 8 is a further perspective view of the core saw viewed from the other end thereof; Figure 9 is a further perspective view of the core saw depicting the protective shroud being lifted to provide access to a cutter blade; Figure 10 is side view of the core saw depicting the protective shroud in the raised condition to provide access to a cutter blade and also with parts removed to reveal internal workings; Figure 11 is a plan view of the arrangement shown in Figure 10; Figure 12 is a perspective view of a drive means adapted to receive a portion of the core holder for conveying the core holder to a cutter; Figure 13 is a side view of the drive means; Figure 14 is a side view of the drive means; Figure 15 is a fragmentary perspective view of the core saw, illustrating the core holder to one side of the delivery trough awaiting insertion into the delivery trough; Figure 16 is a view similar to Figure 15; Figure 17 is a fragmentary perspective view of the core saw, illustrating the core holder being inserted into the delivery trough; and Figure 18 is a view similar to Figure 17, except that the core holder is shown in position in the delivery trough. Best Mode(s) for Carrying Out the Invention [0049] Referring to the drawings, there is shown an automatic core saw 10 for cutting cylindrical core samples 11 longitudinally into two sections 11 a, 11 b. [0050] The core samples 11 to be cut using the automatic core saw 10 are placed in core holders 13, one of which is shown in Figure 3. [0051] As shown in Figure 3, each core holder 13 comprises a body 15 having a base 17, two ends 19, and a V-shaped cradle 21 supported on the base 17 and extending between the two ends 19. The two ends 19 and the cradle 21 are configured to define a central slot 23 along which a cutter blade can pass to cut a core sample supported in the cradle 21 into two longitudinal sections. The body 15 is configured for operative engagement with the core saw 10. In this regard, the body 15 in the arrangement shown has at least one drive lug 20 depending from the base 17, the purpose of which will be explained later. In the arrangement shown, there are a pair of drive lugs 20 depending from the base 17. The pair of drive lugs 20 comprises a first drive lug 21 and a second drive lug 22. In the arrangement shown, the first drive lug 21 and the second drive lug 22 are disposed in side-by-side relation. The pair of drive lugs 20 are disposed at one end 19 of the body. As will be explained later, it is preferable that the pair of drive lugs 20 are at one end 19 of the body 15, although this need not necessarliy be essential. [0052] The core saw 10 further comprises a cutter 30, the operation of which will also be explained later. [0053] The core saw 10 also comprises an upper portion 31 supported on a frame structure 33. The upper portion 31 defines an upper surface 35 in which there is formed an elongate opening 37 configured as a delivery trough 38. The delivery trough 38 is defined between two spaced walls 39 configured as skirts depending from the upper surface 35, and a bottom 40. [0054] The delivery trough 38 is adapted to receive a plurality of the core holders 13 which are conveyed successively to the cutter 30 at which the core sample in each core holder is cut longitudinally into two longitudinal core sections 11a, 11b. While the delivery trough 38 is adapted to receive a plurality of the core holders 13, the core saw 10 can be used with a single core holder, or with only one core holder in the through 38 at any one time, if so desired. [0055] The bottom 40 of the trough 38 is configured as a conveyor means 42 for conveying the core holders 13 to the cutter 30. [0056] The conveyor means 42 comprises a drive means 44 adapted to selectively receive a portion of each core holder 13 for conveying the core holder to the cutter 30. [0057] The conveyer means 42 further comprises a base 46 for receiving and slidably supporting the core holder 13 for movement towards the cutter 30. The base 46 presents a low-friction surface 48 for slidingly supporting the core holder 13 for movement therealong to the cutter 30. In the arrangement shown, the base 46 comprises two tracks 50 in spaced apart relation with a longitudinal opening 52 therebetween. Each track 50 is defined by an elongate element configured as a strip 54 of a low-friction material to present a low-friction surface for slidingly supporting the core holder 13. The strips 54 may be formed of any appropriate material, examples of which include ultra-high molecular density plastic or stainless steel. [0058] The conveyer means 42 further comprises guide means 56 for guiding movement of the core holder 13 within the delivery trough 38 along the base 46. The guide means 56 comprises two guide portions 58 on opposed sides of the base 46, whereby the core holder 13 is receivable between the guide portions 58 for guided movement therebetween. In the arrangement illustrated, the guide portions 58 are configured as guide rails 59 between which the body 15 of the core holder 13 is received for guided movement therebetween, as best seen in Figure 18. [0059] The drive means 44 comprises a cyclically movable structure 60 configured as an endless loop 62. The endless loop 62 comprises a roller chain 64 mounted between two end sprockets 66, one of which is connected to a conveyor drive motor 68. With this arrangement, the roller chain 64 defines an upper run 72 and a lower run 73 each extending between the two end sprockets 66. In this embodiment, the conveyor drive motor 68 comprises an electric motor. [0060] In this embodiment, the roller chain 64 comprises a duplex chain having two chain parts 76, 77 in side-by-side relationship. [0061] By virtue of its construction, the roller chain 64 comprises links 78 having openings 80 within the links. In the duplex chain configuration, the openings 80 are arranged in pairs at intervals along the length of the chain, with each pair 80 comprising a first opening 81 in one chain part 76 and second opening 82 in the other chain part 77. In the arrangement shown, the first opening 81 and the second opening 82 are disposed in side-by-side relation. [0062] The drive lugs 20 on the core holder 13 are configured to be receivable in the openings 80 to provide driving engagement between the roller chain 64 and the core holder 13. With this arrangement, the first and second drive lugs 21, 22 of the core holder 13 can be removably received in the first and second openings 81, 82 to provide driving engagement between the roller chain 64 and the core holder, as best seen in Figure 18. .
[0063] The upper run 72 of the roller chain 64 is disposed on the under-side of the base 46 in alignment with the longitudinal opening 52. In this way, the drive lugs 20 on the core holder 13 can extend through the opening 52 while the core holder 13 is supported on the base 46 to permit engagement between the roller chain 64 and the core holder. [0064]. The cutter 30 is located adjacent one end of the delivery trough 38. The cutter 30 comprises a circular saw blade 92 mounted on a blade shaft 94 which is drivingly connected to a blade drive motor 96 through a belt drive transmission 98. A protective shroud 102 is provided about the exposed part of the blade 92. The shroud 102 is selectively movable to provide access to the blade 92 as necessary. In the arrangement shown, the shroud 102 is movable through pivotal movement manually by the operator (as best shown in Figure 9) between a lowered condition in which it covers the circular saw blade 92 and a raised condition in which it is clear of the circular saw blade 92 to provide access thereot. [0065] A control panel 104 is provided from which an operator can control operation of the core saw 10, including in particular the conveyor drive motor 68 and the blade drive motor 96. The control panel 104 includes a display 105 providing information regarding operation of the core saw 10, including operational characteristics of the the conveyor drive motor 68 and the blade drive motor 96. The control panel 104 also includes various control elements 106 such as switches and a control knob. In the arrangement shown, the control panel 104 is mounted on the shroud 102 [0066] The core saw 10 is fitted with a holding station 110 to temporarily hold one or more core holders 13 awaiting insertion into the delivery trough 38. In the arrangement shown, the holding station 110 is located on upper surface 35 alongside the delivery trough 38, as shown in the drawings. . [0067] The holding station 110 comprises two support rails 112 in side-by-side relation with a space 114 therebetween. With this arrangement, the core holders 13 can rest on the rails 112, with the drive lugs 20 accommodated in the space 114. [0068] Each support rails 112 is defined by an elongate element configured as a strip 116 of a low-friction material to present low-friction surface for slidingly supporting the core holders 13. In this way, the core holders 13 can be conveniently moved along the support rails 112 if necessary. The strips 116 may be formed of any appropriate material, examples of which include ultra-high molecular density plastic or stainless steel. [0069] The holding station 110 may provide a useful area at which core samples 11 can be loaded into core holders 13 prior to the latter being inserted into the delivery trough 38. [0070] When a core sample cutting operation is to be performed, the core saw 10 is activated at the control panel 104 to start the blade drive motor 96 and the conveyor drive motor 68. A core sample 11 to be cut is placed in a core holder 13, and the core holder 13 is then inserted into the delivery trough 38, with the core holder oriented such that the drive lugs 20 are at trailing end of the core holder with respect to the direction of movement of the core holder along the delivery trough towards the cutter 30. The core holder 13 rests on the base 46, with the drive lugs 20 extending through the central longitudinal opening 52 and into engagement with the upper run 72 of the roller chain 64. The drive lugs 20 can locate in any available pair of openings 80 within the roller chain 64, with first lug 21 locating in opening 81 and the second lug 22 locating in opening 82. [0071]The core holder 13 can be inserted into the delivery trough 38 while the roller chain 64 is either stationary or moving. The ability to insert a series of core holder 13 one after another allows core samples to be continually fed to the cutter 30 while the core saw 10 is in operation. An operator merely places the respective core holder 13 into the delivery trough 38. Typically, the operator would first position the leading end of the core holder 13 on the base 46, with the trailing end at which the drive lugs 20 are located initially raised about the base 46 such that the drive lugs 20 are not initially presented to the moving upper run 72 of the roller chain 64, as shown in Figure 17. The operator then releases the core holder 13 so that it pivots down to fully rest on the base 46, such that the drive lugs 20 register with, and locate in, an available pair of openings 80 in the roller chain 64, as shown in Figure 18 The moving upper run 72 causes the core holder 13 to slide along the base 46. In this way, the core holder 13 is conveyed along the trough 38 to the cutter 30. At the cutter 30, the saw blade 92 contacts the core sample 11 and commences the cutting action. The cutting action continues as the core sample 11 is carried past the rotating saw blade 92, cutting the core sample longitudinally into two sections 11a, 11b. The upper run 72 of the roller chain 62 conveys the core holder 13, as well as the cut core sample held in the core holder 13, beyond the cutter 30 to a discharge chute 120 from which the core holder and cut core sample can be retrieved. [0072] The shroud 102 incorporates a flexible extension 121 which extends downwarding into the trough 38 to contact the bottom 40 thereof on the outerside of the circular saw blade 92 of the cutter 30. In the arrangement shown, the flexible extension 121 comprises a rubber flap 123, as shown in Figures 6 and 7.. The rubber flap 123 provides a shield functioning as a safety feature to prevent the operator or any other person in the vicinity from inadvertently contacting the cutter blade 92 through the discharge end of the delivery trough 38. Further, the rubber flap 123 may also assist in limiting the discharge of dust generated during the cutting operation through the discharge end of the delivery trough 38. The rubber flap 123 can ride over the core holder 13 and the cut core sample held in the core holder as the core holder movered from the delivery trough 38 onto the discharge chute 107, as shown in Figure 7. [0073] The delivery trough 38 is of a length which can accommodate several core holders 13 in a queue, with the queue of core holders progressively advancing towards the cutter 30 under the action of the moving roller chain 64. [0074] A particular advantage of the arrangement of the present embodiment is that a core holder 13 can be placed at any available position within the delivery trough 38 as determined by the location of the openings 80 in the roller chain 64.. The positioning of the core holder 13, or core holders, in the trough 38 is not dictated by the location of feed pins as in the case of prior art core saws of the type described previously. [0075] Further, the core holders 13 need not necessarily be of standard lengths as is required for prior art core saws of the type described previously in which the required length of the core holders is dictated by the spacing between feed pins. . Indeed, with the present embodiment longer core holders 13 can be accommodated in the delivery trough 38 (if there is ever a need to cater for longer core samples). [0076] The delivery trough 38 is dimensioned such that the core holders 13 received therein are accessible by a saw operator. Specifically, the delivery trough 38 is of a depth such that an upper portion of each core holder 13 is accessible (typically by hand) when the core holder is in the trough. With this arrangement, the saw operator is able to conveniently insert the core holder 13 into the delivery trough 38 and also, if necessary, lift the core holder out of the trough.
[0077] Further, the saw operator is also able to grasp a particular core holder 13 which is in the delivery trough 38 and manually advance it along the delivery trough towards the cutter 30 by lifting the trailing end of the core holder to release the drive lugs 20 from engagement with the roller chain 64 and then pushing the core holder along the delivery trough to the desired position, at which it can be released to allow the drive lugs 20 to re-engage with the roller chain 64.. This is advantageous if the saw operator wishes to advance the core holder 13 towards the cutter 30 at a rate faster than that at which it is able to be conveyed by the moving upper run 72 of the roller chain 64. This cannot be done with prior art core saws of the type described previously because of the presence of the feed pins which obstruct manual movement of the core holders along the trough. [0078] Additionally, the saw operator is also able to grasp a core holder 13 in the delivery trough and manually retract it along the delivery trough away from the cutter 30 in a similar manner. This is advantageous if the saw operator wishes to interrupt or terminate cutting of the particular core sample 11 in the core holder 13. A circumstance in which this might arise is where the cutter 30 is overloaded or jammed while performing a cutting action on the core sample. Again, this cannot be done with prior art core saws of the type described previously because of the presence of the feed pins which obstruct manual movement of the core holders along the trough. [0079] From the foregoing, it is evident that the present embodiment provides a simple yet highly effective arrangement for conveying core samples in core holders to a cutter at which the core samples can be cut longitudinally into sections [0080] It should be appreciated that the scope of the invention is not limited to the scope of the embodiment described. In particular, while the present invention has been described in terms of a preferred embodiment in order to facilitate better understanding of the invention, it should be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope. [0081] Reference to positional descriptions, such as "upper", "lower", "top" and "bottom", are to be taken in context of the embodiments depicted in the drawings, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.
[0082] Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.