Patent Publication Number: US-2016236289-A1

Title: Saw table, band saw apparatus and a method for sawing

Description:
FIELD 
     The invention is provided in the field of saw tables for use in a band saw apparatus and a band saw apparatus optionally comprising the saw table according to the invention. The invention also relates to a method for sawing. 
     BACKGROUND 
     Band saw apparatus are well-known in the art for a variety of sawing applications, such as sawing plates and beams made of wood, steel or another suitable material. In general terms band saw apparatus comprise a band saw frame holding a driveable band saw and a saw table for supporting a workpiece that needs processing. 
     A more versatile variant of a band saw apparatus is the miter cutting band saw apparatus, which is capable of providing chamfered ends to workpieces. An example of such an apparatus is a miter band saw by Voortman Steel Machinery Holding B.V that is intended for miter cutting of, amongst others, steel profiles. The band saw apparatus comprises a swivel frame and a saw assembly comprising a saw frame. The saw frame is upwardly and downwardly movably connected to the swivel frame. The swivel frame is rotatably mounted on a base frame to provide miter cutting. The band saw apparatus further comprises a saw table, which is fixedly connected to the swivel frame, and a saw band that is driveably connected to the saw frame. The saw table is provided with saw lists that define a cut out section for the saw band. During miter cutting, the swivel frame and thus the saw table are both rotated relative to the base frame. This has the advantage that the saw band remains in line with the cut out section. 
     The Voortman band saw apparatus is commonly used with a feed-in transport conveyor and a discharge transport conveyor. The circular saw table is positioned between the feed-in and the discharge transport conveyors. In such a set-up, the rotation of the swivel frame and the integrated saw table require a clear space between the saw table and the feed-in and discharge conveyors. This clear space results in a gap between the saw table and the feed-in and/or feed-out transport conveyors. This makes it difficult to process short workpieces and incurs the risk of workpieces falling in the gap between the transport conveyors and the saw table. 
     Another band saw apparatus which is known from the prior art is the Peddinghaus DGP-1270 band saw apparatus. The Peddinghaus DGP-1270 band saw apparatus does not have a circular band saw table which rotates with the swivel frame but, instead, comprises a portal frame in which a swivel frame is rotatably mounted along a vertical axis. The band saw apparatus also comprises a transport conveyor which is positioned under the portal frame and has the function of saw table. The swivel frame carries a band saw frame which is upwardly and downwardly movable along the swivel frame. The band saw frame is configured for holding a saw band. By rotating the swivel frame within the portal frame, the saw band can be positioned at a miter angle. The transport conveyor which also has the function of saw table extends within a band saw workrange and also extends upstream and downstream of the band saw workrange without the presence of gaps. 
     The transport conveyor or band saw table comprises a frame with transport rollers for transporting and supporting the workpiece in the transport direction. The transport rollers extend substantially perpendicular to the transport direction from a first side to a second side of the saw table along substantially the entire saw table. The transport rollers are movable between an upper position, in which they support the workpiece, and a lower position. The saw table further comprises saw lists that are positioned in the gaps between the transport rollers to support the workpiece during sawing. In order to provide this support, the saw lists are installed at a fixed height and are mainly disposed in the band saw working area. 
     A resulting disadvantage from the design of the Peddinghaus apparatus is that, during sawing, the saw band also cuts into the saw lists that support the workpiece. Consequently, the saw lists are damaged and must be replaced frequently. 
     JP H05 104325 A discloses a saw table including transport rollers that together define a substantially horizontally oriented transport surface on which a workpiece is transportable in a transport direction and that are upwardly and downwardly movable between an upper position, in which the transport rollers can support and transport workpieces, and a lower position. The known saw table also includes workpiece support elements, such as workpiece support-conveyors or workpiece support-lists, which support elements that are positioned in gaps between successive transport rollers, wherein the upward facing sides of the workpiece support elements are at a higher level than the upward facing sides of the transport rollers when the transport rollers are in the lower position, and wherein the upward facing sides of the workpiece-support elements are at a lower level than the upward facing sides of the transport rollers when the transport rollers are in the upper position. The length of the transport rollers and the support elements of the support table is not constant so that a free end of the saw frame can move downwardly below the level of the transport surface when it is at an angled position relative to the transport direction as shown in the dot-dashed lines in the top view of  FIG. 1 . As is clearly visible derivable from  FIG. 1  and  FIG. 4 , the lower part of the saw band will contact and damage the work piece support-lists when the saw frame is in an angled position relative to transport direction and has moved downwardly as shown in the dot-dashed lines of  FIG. 4 . 
     US 2002/0020610 A1 relates to a conveyor device for a miter-box saw. The known conveyor device includes transport rollers. When the saw frame of the miter saw is in a non-perpendicular miter position, i.e. swivelled relative to the transport direction of the conveyor device, then the transport rollers of the conveyor device are moved away in a horizontal direction out of the working area of the saw band. Consequently, the support surface for the workpiece is reduced in this known conveyor device. The known conveyor device does not include workpiece support elements that are positioned in the gaps between successive transport rollers. Further, the transport rollers are not upwardly and downwardly moveable. 
     DE 31 05 470 is a conventional saw table including only transport rollers. Work piece support elements that are positioned in gaps between successive transport rollers are missing in this publication. Further, the transport rollers are not upwardly and downwardly movable between an upper position and a lower position but are instead fixed. Support of the workpieces during sawing is not optimal with this known design 
     US 2006/0090623 also relates to a miter saw. The miter saw includes a support device which contains transport rollers. The rollers are not moveable upwardly and downwardly. In the work range of the saw band a table top is arranged at the same level as the upper sides of the transport rollers. The table top is a replaceable part. The saw cuts into the table top during the sawing process. With time, the table top is consumed. Such a replacement part renders the use of the known saw expensive. 
     SUMMARY 
     The invention is aimed at solving the disadvantages of the prior art by providing an improved saw table for use with a band saw apparatus in which damage of the workpiece-support elements is alleviated while still providing an optimized support for the workpieces. To that end, the invention provides a saw table for use in a band saw apparatus, comprising:
     a saw table frame;   transport rollers that together define a substantially horizontally oriented transport surface on which a workpiece is transportable in a transport direction, wherein the transport rollers are positioned in a transport range that, viewed in the transport direction, extends over some distance upstream and some distance downstream of a neutral plane that extends vertically and perpendicularly to the transport direction, wherein the transport range comprises a first longitudinal side and a second longitudinal side that extend parallel to each other in the transport direction, wherein the transport rollers are upwardly and downwardly movable between an upper position in which the transport rollers can support and transport workpieces, and a lower position;
 
characterised in that workpiece support elements, such as workpiece support-conveyors or workpiece support-lists, are positioned in gaps between successive transport rollers, wherein the upward facing sides of the workpiece support elements are at a higher level than the upward facing sides of the transport rollers when the transport rollers are in the lower position, and wherein the upward facing sides of the workpiece-support elements are at the same level or at a lower level than the upward facing sides of the transport rollers when the transport rollers are in the upper position, wherein the workpiece support elements are configured to leave a saw band workrange clear, wherein the saw band workrange is formed by a three-dimensional space in the form of a right prism with a triangular, horizontally oriented base, wherein the triangular base has an apex that is substantially positioned in a vertical plane in which the first longitudinal side extends and wherein the apex is positioned in the neutral plane, and wherein the triangular base has a base line that is positioned in a vertical plane in which the second longitudinal side extends, wherein the three-dimensional space of the saw band workrange extends above the transport surface and at least over a predetermined distance below the transport surface.
   

     The band saw table according to the invention has the advantage that the workpieces are supported throughout the process without incurring damage to any of the support elements that support the workpiece. In this respect, it should be noted that the feature, wherein the workpiece support elements are configured to leave a saw band work range clear, should be understood as, wherein the workpiece support elements do not extend in a saw band work range. The exact configuration of the saw band work range is defined later in claim. In the prior art, the workpiece support elements (i.e. the saw lists which are required to support the workpieces) are present in the workrange of the saw band during sawing. The resulting damage and, thus, higher maintenance costs and standstill periods are accepted. In the saw table according to the invention, the workpiece support elements are designed to support workpieces during sawing without being present in the band saw workrange. As a result, no damage is incurred to the workpiece support elements while still providing the required support to the workpiece that is to be sawed. An increase in the lifetime of the workpiece support elements and therefore a reduction of maintenance costs is achieved using the band saw table according to the invention. In addition, the productivity and availability of the band saw table and a band saw apparatus having comprises a saw table according to the invention is increased as less maintenance is required. 
     Another advantage of the saw table according to the invention is that it is capable of supporting even short workpieces (i.e. &gt;450 mm in length for a standard I-beam having a height of approximately 260 mm) without the workpiece support elements being damaged or providing insufficient support to the workpiece. 
     The saw table may naturally be integrated with existing transport rollers, which may allow seamless integration in existing processes and production facilities. The saw table may even be integrated in existing band saw apparatus from the prior art in order to mitigate the disadvantages of those apparatus. 
     In addition, the transport rollers of the saw table can be provided as driven or non-driven transport rollers. Driven transport rollers may provide for an easier integration of the saw table and existing workpiece transport system. 
     The invention also comprises a band saw apparatus, comprising:
     a saw table according to the invention;   swivel frame connected to a support frame, such that it is swivable around a vertical centreline C in a swivel range,   a saw-assembly comprising:
       a saw frame that is upwardly and downwardly movably connected to the swivel frame;   at least two saw band pulleys that are connected to the saw frame of which at least one is drivable with a saw band driving motor;   a saw band that is guided over the saw band pulleys, wherein the saw band is provided with a cutting edge and wherein a lower part of the saw band is working during sawing;   
       a saw-assembly driving motor, configured to move the saw-assembly upward and downward;   

     wherein the swivel frame has a neutral position from which the swivel frame is swivable in an upstream and a downstream position, such that the lower part of the saw band is exclusively positionable in the saw band workrange, wherein the cutting edge of the saw band extends in the neutral plane N when in a neutral position. 
     The band saw apparatus comprising the saw table according to the invention has several advantages. First of all, the saw table does not have gaps between an upstream and a downstream transport conveyor and the saw table. Moreover, the transport rollers and the saw table may be integrated with an upstream and downstream transport conveyor of the roller type to provide a continuous transport surface for the workpieces. In addition, the band saw apparatus according to the invention also solves the disadvantage of the Peddinghaus band saw apparatus as the swivel frame and the saw assembly are cooperating to prevent damage to the saw table, while still allowing a high throughput and availability. As such, an improved band saw apparatus is provided with the invention. 
     The invention also provides a band saw machine, that maybe but does not have to be applied with the saw table according to the invention. This band saw machine comprises:
     a swivel frame connected to a support frame, such that it is swivable around a vertical centreline in a swivel range,   a saw-assembly comprising:
       a saw frame that is upwardly and downwardly movably connected to the swivel frame;   at least two saw band pulleys that are connected to the saw frame of which at least one is drivable with a saw band driving motor;   a saw band that is guided over the saw band pulleys, wherein the saw band is provided with a cutting edge and wherein a lower part of the saw band is active during sawing;   
       a saw-assembly driving motor, configured to move the saw-assembly upward and downward;
 
wherein the swivel frame has a neutral position from which the swivel frame is swivable in an upstream and a downstream position, such that the lower part of the saw band is exclusively positionable in a saw band workrange, wherein the cutting edge of the saw band extends in the neutral plane (N) when in a neutral position;
 
wherein the band saw machine additionally comprises:
   a guiding assembly, which upwardly and downwardly movably connects the saw frame with the swivel frame, wherein the guiding assembly is also configured for providing a tilting movement of the saw frame with respect to the swivel frame in a vertical plane parallel to the swivel frame, wherein the saw assembly is positionable in a tilted state and a non-tilted state, wherein the cutting edge of the saw band in a tilted state includes an angle with a horizontal transport surface of a saw table, and wherein the cutting edge of the saw band in a non-tilted state extends parallel to the transport surface of the saw table.   

     In such a band saw apparatus, the guiding assembly and may be configured to provide the tilting movement with the same saw-assembly driving motor that is configured to move the saw-assembly upward and downward. A configuration in which the tilting movement may be effected with the same motor that also controls the upward and downward movement of the saw-assembly is advantageous in view of costs and in view of maintenance of the band saw apparatus. An embodiment for enabling the combined use of the saw-assembly driving motor is described in the detailed description. 
     The invention also provides a method for sawing workpieces using a band saw apparatus, the method comprising:
     providing a band saw apparatus according to the invention;   transporting a workpiece that needs to be sawed to a sawing position using the transport rollers, wherein the transport rollers are positioned in the upper position;   moving the transport rollers from the upper position to the lower position, such that the workpiece that needs to be sawed is supported by the workpiece support elements;   sawing the workpiece, and;   moving the transport rollers from the lower position to the upper position to transport the sawed workpiece downstream or upstream using the transport rollers.   

     Various embodiments are claimed in the dependent claims, which will be further elucidated with reference to some examples shown in the figures. The embodiments may be combined or may be applied separate from each other. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
         FIG. 1  depicts a perspective view of a first embodiment of the saw table and the band saw apparatus according to the invention; 
         FIG. 2  depicts a schematic top view of the saw table and the band saw apparatus of  FIG. 1 ; 
         FIG. 3  shows a second embodiment of the saw table according to the invention; 
         FIG. 4  depicts a schematic side view of the saw table and the band saw apparatus of  FIG. 1 , with the saw assembly being in a tilted state; 
         FIG. 5  depicts a schematic side view of the saw table and the band saw apparatus of  FIG. 1 , with the saw assembly being in a non-tilted state. 
     
    
    
     DETAILED DESCRIPTION 
     In this application similar or corresponding features are denoted by similar of corresponding reference signs. The description of the various embodiments is not limited to the examples shown in the figures and the reference numbers used in the detailed description and the claims are not intended to limit the description of the embodiments. The reference numbers are included to elucidate the embodiments by referring to the examples shown in the figures. In general terms, the invention comprises a saw table  10  for use in a band saw apparatus that comprises a saw table frame  12  in which transport rollers  14  are mounted such that they together define a substantially horizontally oriented transport surface on which a workpiece is transportable in a transport direction. The transport rollers  14  are positioned in a transport range that, viewed in the transport direction, extends over some distance upstream and some distance downstream of a neutral plane N that extends vertically and perpendicularly to the transport direction. The transport range comprises a first longitudinal side  16   a  and a second longitudinal side  16   b  that extend parallel to each other in the transport direction. The transport rollers  14  are upwardly and downwardly movable between an upper position in which the transport rollers  14  can support and transport workpieces, and a lower position. The saw table  10  is characterised in that workpiece support elements  18 , such as workpiece support conveyors or workpiece support lists, are positioned in gaps between successive transport rollers  14 . The upward facing sides of the workpiece support elements  18  are at a higher level than the upward facing sides of the transport rollers  14  when the transport rollers  14  are in the lower position. The upward facing sides of the workpiece-support elements  18  are at the same level or at a lower level than the upward facing sides of the transport rollers  14  when the transport rollers  14  are in the upper position. The workpiece support elements  18  are configured to leave a saw band workrange  20  clear. The saw band workrange  20  is formed by a three-dimensional space in the form of a right prism with a triangular, horizontally oriented base. The triangular base has an apex that is substantially positioned in a vertical plane in which the first longitudinal side  16   a  extends. The apex is also positioned in the neutral plane N. The triangular base has a base line that is positioned in a vertical plane in which the second longitudinal side  16   b  extends. The three-dimensional space of the saw band workrange  20  extends above the transport surface and also extends at least over a predetermined distance below the transport surface. 
     The advantages of the saw table  10  have been provided in the summary, to which is referred here. Two examples of the saw table and an example of the band saw apparatus according to the invention are shown in  FIGS. 1-5 . 
       FIG. 2  clearly shows the distinction between the transport rollers  14  and the workpiece support elements  18  that have a limited length in a direction perpendicular to the transport direction compared to the transport rollers  14 . The delineation of the triangular, horizontally oriented base of the saw band workrange  20  is clearly visible as the triangle formed by lines I-I′ and I′-I′ in  FIG. 2 . 
     In a first embodiment, an example of which is shown in  FIGS. 1-2, 4 and 5 , the workpiece support elements  18  may extend substantially horizontally from the first longitudinal side  16   a.  The length of the workpiece support elements  18  may be such that these do not reach into the saw band workrange  20 . 
     By adjusting the length of the workpiece support elements  18  such that they do not reach into the saw band workrange  20 , the saw band is prevented from sawing into the workpiece support elements  18  and thus prevented from damaging them. An example of the embodiment is provided in  FIGS. 1 and 2 , which clearly that the saw band workrange  20  being kept clear. Naturally, the length of the workpiece support elements  18  may be adapted to a variety of saw band workranges  20  in that a saw table  10  with a limited saw band workrange  20  may be provided with workpiece support elements  18  that are longer than the workpiece support elements  18  that may be provided in a saw table  10  with a wider saw band workrange  20 . 
     In a second embodiment the workpiece support elements  18  may extend substantially horizontally from the first longitudinal side  16   a  to the second longitudinal side  16   b.  The upward facing side of each workpiece support element  18  that, when viewed from above, passes the saw band workrange  20  may be provided with a recess  22 , such that the upward facing sides of the recesses  22  are positioned below the saw band workrange  20 . 
     This embodiment may provide an alternative solution to prevent damage to the workpiece support elements  18  during sawing. The recesses  22  provided in the workpiece support elements  18  may be designed such that the workpiece support elements  18  are not located in the band saw-workrange  20  during sawing, as can for example be seen in  FIG. 3 . The recesses  22  in the workpiece support elements  18  that pass the saw band workrange  20  when viewed from above may be provided such that the saw table may be used in band saw apparatus with a variety of saw band workranges  20  (i.e. both small and wider miter ranges). Furthermore, the saw table  10  according to this embodiment may advantageously be retrofitted in existing band saw apparatus as it may provide continuous support to workpieces while taking away at least some of the disadvantages present in the prior art apparatus. 
     The invention further comprises a band saw apparatus  24 , comprising a saw table  10  according to the invention and a swivel frame  26  that is connected to a support frame  28 , such that it is swivable around a vertical centreline C in a swivel range. It also comprises a saw-assembly  30  comprising a saw frame  32  that is upwardly and downwardly movably connected to the swivel frame  26 . The saw assembly  30  may further comprise at least two band saw pulleys that are connected to the saw frame  32  of which at least one is drivable with a band saw driving motor  33 . A band saw  34  is guided over the band saw pulleys. The saw band  34  is provided with a cutting edge and a lower part of the saw band  34  is active during sawing. Furthermore, the band saw apparatus  24  comprises a saw-assembly driving motor  36 , that is configured to move the saw-assembly  30  upward and downward. The swivel frame  26  has a neutral position from which the swivel frame  26  is swivable in an upstream and a downstream direction, such that the lower part of the saw band  34  is exclusively positioned in the band saw workrange  20 . The cutting edge of the saw band  34  extends in the neutral plane N when in a neutral position. 
     As referred to in the summary, the band saw apparatus  24 , of which a perspective view of an example is provided in  FIG. 1 , is advantageous over the prior art. The saw table  10 , the swivel frame  26  and the saw assembly  30  configured to provide optimal support to the workpieces both before, during and after sawing and are cooperating to prevent damage to the saw table  10 , while still allowing a high throughput and availability. 
     In an embodiment the saw table  10  further may comprise at least one saw list  38   a,    38   b  that may extend perpendicular to the transport direction from the first longitudinal side  16   a  of the saw table  10  to the second, opposite longitudinal side  16   b  of the saw table  10 . An upper side of the saw list  38   a,    38   b  may define a support surface for supporting a workpiece. The at least one saw list  38   a,    38   b  may be upwardly and downwardly movable between a lower position, in which the support surface extends below the triangular base of the saw band workrange  20  and an upper position in which the support surface extends in the saw band workrange  20 . In the support position, the support surface may be at a substantially the same vertical level as the upwardly facing sides of the workpiece support elements  18  positioned outside the band saw workrange  20 . 
     The band saw table may be provided with one or more saw lists  38   a,    38   b  to prevent vibrations in the workpiece and the band saw apparatus  24  during sawing. Examples thereof are clearly visible for example in  FIGS. 1 and 2 .  FIG. 1  clearly shows an example of a band saw apparatus  24  having a saw table  10  with two saw lists  38   a,    38   b.  In order to prevent damage, the at least one saw list  38   a,    38   b  in this embodiment is upwardly and downwardly movable between a lower and an upper position. This allows the saw lists  38   a,    38   b  to be lowered in the lower position during miter cutting, thus preventing the saw lists  38   a,    38   b  to be damaged by the saw band  34 . When not providing miter sawing operations, the saw lists  38   a,    38   b  may be held in the upward position in order to provide support to the workpiece. Thus a more durable band saw apparatus  24  is provided. 
     In an embodiment, the band saw workrange  20  may be provided with an upstream band saw workrange part  20   a  that, viewed in the transport direction is positioned upstream of the neutral plane N. The band saw workrange  20  may be provided with a downstream band saw workrange part  20   b  that, viewed in the transport direction, may be positioned downstream of the neutral plane N. An upstream saw list  38   a  may extend parallel and directly upstream of said neutral plane N. Furthermore, a downstream saw list  38   b  may extend parallel and directly downstream of said neutral plane N. When the saw band  34  is positioned in the upstream band saw workrange part  20   a  during sawing of a workpiece, the upstream saw list  38   a  may be in a lower position and the downstream saw list  38   b  may be in an upper position. When the saw band  34  is positioned in the downstream band saw workrange part  20   b  during sawing of a workpiece, the downstream saw list  38   b  may be in a lower position and the upstream saw list  38   a  may be in an upper position. 
     By having at least two saw lists and allowing the saw lists  38   a,    38   b  to move independently from each other, an improved support for the workpiece may be achieved. A workpiece may not only be supported by the workpiece support elements  18 , but may, in this embodiment, even during miter sawing, also be supported by at least one saw list  38   a,    38   b.  As a result, an improved support for the workpiece will be provided. Also, the presence of at least one saw list  38   a,    38   b  may have improved vibration reduction in the saw band  34  during sawing. Naturally, the saw list  38   a,    38   b  that is present in the same band saw workrange-part  20   a,    20   b  in which the saw band  34  is active, is in a lower position so that it will not be damaged during sawing. As a result, this embodiment provides increased saw band and workpiece vibration reduction while still preventing the saw lists  38   a,    38   b  and/or the workpiece support elements  18  from being damaged. 
     In an embodiment the saw table  10  may be provided with a workpiece-clamp-assembly comprising a backstop  42 , which may be positioned near the first longitudinal side  16   a  of the saw table  10  and which may extend in an upward direction parallel to the vertical centreline C. The backstop  42  may be provided with a slit through which the lower part of the saw band  34  may extend during sawing. The workpiece-clamp-assembly comprises a workpiece-clamp  44 . The workpiece-clamp  44  may be movable from and towards the backstop  42  in a direction perpendicular to the transport direction for clamping a workpiece between the backstop  42  and the workpiece-clamp  44  during sawing of a workpiece. Furthermore, the workpiece-clamp-assembly may comprise a workpiece-clamp guiding rail  46 . The workpiece-clamp guiding rail  46  may be positioned near the second longitudinal side  16   b  of the saw table  10  and may extend in the transport direction. The workpiece-clamp  44  may be mounted on the workpiece-clamp guiding rail  46 , such that the workpiece-clamp  44  may be movable in an upstream and a downstream direction. 
     The workpiece-clamp assembly, such as for example shown in  FIGS. 1 and 2 , may advantageously be used to clamp the workpiece during sawing. To reduce vibrations in the workpiece, the workpiece is clamped near the saw band  34 . Providing a workpiece-clamp assembly according to this embodiment may allow clamping of the workpiece near the saw band  34  without incurring the risk of accidentally sawing into the workpiece-clamp  44  during sawing. This may be achieved by moving the workpiece-clamp  44  along the workpiece-clamp guiding rail  46  such that it is not positioned underneath the saw band  34 . 
     In an embodiment of the band saw apparatus, which may also be applied in combination with a conventional saw table which does not include all features of claim  1 , the band saw apparatus comprises a guiding assembly  48 . The guiding assembly is configured to upwardly and downwardly movably connect the saw frame  32  with the swivel frame  26 . The guiding assembly  48  may also be configured for providing a tilting movement of the saw frame  32  with respect to the swivel frame  26  in a vertical plane parallel to the swivel frame  26 . The saw assembly  30  may be positionable in a tilted state and a non-tilted state. The cutting edge of the saw band  34  may in a tilted state include an angle with a transport surface of a saw table, for example the saw table  10  which has been described above. An example of a saw assembly in the tilted state is shown in  FIG. 4 . The cutting edge of the saw band  34  in a non-tilted state extends parallel to the transport surface of the saw table  10 , such as for example shown in  FIG. 5 . 
     In an embodiment of the band saw apparatus, which may also be applied in combination with a conventional saw table which does not include all features of claim  1 , the guiding assembly  48  may comprise a first guiding rail  50   a  that may be fixedly connected with the swivel frame  26 . The first guiding rail  50   a  may be provided with at least one upwardly and downwardly movably connected guiding element  52 . The guiding assembly  48  may comprise a second guiding rail  50   b  that may be fixedly connected to the swivel frame  26  and that may extend parallel to the first guiding rail  50   a.  The second guiding rail  50   b  is provided with at least one upwardly and downwardly movably connected guiding element  52 . The said guiding elements  52  may be connected with the saw frame  32 . A connection of one of the guiding elements  52  with the saw frame  32  may be configured to exclusively allow tilting of the saw frame  32  with regard to the said guiding element  52 . Additionally, each connection of the remaining guiding elements  52  with the saw frame  32  may be configured to allow tilt and translation of the saw frame  32  with respect to the guiding elements  52  concerned. 
     A guiding assembly having two guiding rails  50   a,    50   b  with multiple guiding elements  52  has several advantages. First of all, having multiple guiding elements  52  may provide a stable construction with minimized vibrations. Providing one guiding element  52  that is configured to exclusively allow tilting of the saw frame  32  with regard to the said guiding element  52 , while the other guiding elements  52  are configured to provide both translation and tilt is advantageous. Such a construction allows the saw assembly  30  and the saw band  34  to be tilted during sawing of the workpiece. This may for example allow the cutting angle to be reduced to 0° when nearing the saw table  10 , which may reduce the distance the saw band  34  reaches below the transport surface of the saw table  10 . Thus, the triangular base of the right prism forming the band saw working range  20  will be at a higher level. Consequently, the distance that the transport rollers need to be lowered to clear the band saw workrange  20  can be reduced. 
     In an embodiment, the guiding assembly  48  and the saw assembly motor  36  may cooperate to adjust the saw assembly  30  from a tilted to a non-tilted state and vice versa. 
     Using the saw assembly motor  36  to cooperate with the guiding assembly  48  to adjust the tilt of the saw assembly  30  obviates the need for a second motor for tilting adjustment of the saw assembly  30 . This reduces manufacturing and material costs. 
     In an embodiment, the guiding assembly  48  may comprise a blocking element  54 . In a blocking state the blocking element  54  may be configured to block the translation movement of at least one of the guiding elements  52  that allow tilting and translation of the saw frame  32  with respect to the associated guiding element  52 . The blocking may be such that the saw frame  32  may be kept in a fixed tilted state. The blocking element  54  may be movable to a deblocking state, wherein the translation movement of the guiding element  52  relative to the saw frame  32  is possible and a tilting movement of the saw frame  32  to a non-tilted state and vice versa. 
     In an embodiment, the guiding assembly  48  may comprise a blocking element control assembly  56 . The blocking element control assembly  56  may be provided with an actuator. The saw assembly  30  may be provided with a stop that is connected to the saw frame  32  near an end of the saw frame  32  to which the guiding element  52  that only allows rotation is also connected. The blocking element control assembly  56  may be configured to bring the blocking element  54  in a deblocking state when the the stop comes in contact with the actuator. The blocking element control assembly  56  may be configured to bring the blocking element  54  in the blocking state when the stop is not in contact with the actuator. 
     This embodiment may provide an automatic adjustment of the cutting angle of the saw band  34  during sawing, which is specifically advantageous while miter cutting. The blocking element control assembly  56  may be used to deblock the blocking element  54  when the saw assembly  30  during sawing is getting near to the saw table  10 . By adjusting the angle of the saw band  34  to 0°, the saw band  34  reaches less far below the transport surface of the saw table  10 . The distance that the transport rollers need to be lowered to clear the band saw workrange  20  may therefore be reduced in this embodiment of the band saw apparatus  24 . 
     In an embodiment the blocking element  54  may be a hydraulic cylinder. The hydraulic cylinder may be adjustable from a high pressure state to a low pressure state and vice versa. The high pressure state may therein correspond with the blocking state, and the low pressure state may correspond with the deblocking state. 
     The advantage of a hydraulic cylinder as a blocking element is that the transfer from a high pressure state to a low pressure state can be easily controlled. This may allow for a gradual lowering of the saw assembly  30  and a gradual reduction of the angle of the saw band  34  with the transport surface of the saw table  10 . This produces a smooth operation of the band saw apparatus  24 . In the low pressure state, the hydraulic cylinder is kept at a slightly lower pressure than the pressure needed to keep the saw assembly  30  in equilibrium. As a result, the saw assembly  30  gradually tilts towards an angle of 0° under its own weight. 
     In an embodiment, the angle between the cutting edge of the saw band  34  and the transport surface of the saw table  10  may be varied by tilting in the range of 0° to 20°. The tilt angle may preferably be in the range of 0° to 10°. More preferably, the tilt angle may be in the range of 0° to 4°. 
     In an embodiment, the band saw apparatus  24  also may comprise a workpiece positioning assembly configured for positioning a workpiece on the saw table  10 , such that the workpiece may be sawed at a predetermined location. 
     A workpiece positioning assembly may be used in for positioning the work piece. 
     In addition, the invention also provides a method for sawing workpieces using a band saw apparatus. The method comprises:
     providing a band saw apparatus  24  including a saw table according to the invention;   transporting a workpiece that needs to be sawed to a sawing position using the transport rollers  14 , wherein the transport rollers  14  are positioned in the upper position;   moving the transport rollers  14  from the upper position to the lower position, such that the workpiece that needs to be sawed is supported by the workpiece support elements  18 ;   sawing the workpiece, and;   moving the transport rollers  14  from the lower position to the upper position to transport the sawed workpiece downstream or upstream using the transport rollers  14 .   

     In an embodiment, the method also comprises providing a band saw apparatus  24  with a saw table having vertically movable saw lists  38   a,    38   b,  wherein the method also comprises determining whether the saw band  34  is positioned in the upstream saw band workrange part  20   a  or in the downstream saw band workrange part  20   b  for sawing the workpiece. It subsequently also comprises moving the upstream saw list  38   a  from the upper position to the lower position if the saw band  34  is positioned in the upstream saw band workrange part  20   a,  or moving the downstream saw list  38   b  from the upper position to the lower position if the saw band  34  is positioned in the downstream saw band workrange part  20   b.    
     In an embodiment, the method comprises providing a band saw apparatus  24  having a saw table according to an embodiment of the invention having a workpiece-clamp  44 , wherein the method comprises moving the workpiece-clamp  44  parallel to the transport direction along the workpiece-clamp guiding rail  46  to a clamping position. The clamping position is chosen such that the workpiece to be sawed can be clamped between the workpiece-clamp  44  and the backstop  42  and the workpiece-clamp  44  is not positioned underneath the saw band  34 . The method additionally comprises clamping the workpiece to be sawed between the backstop  42  and the workpiece-clamp  44 . This is performed by moving the workpiece-clamp  44  perpendicularly to the transport direction towards the backstop  42 . 
     In an embodiment, in which the band saw apparatus  24  is embodied according to any one of the claims  8 - 15 , the method further comprises bringing the saw assembly  30  in a tilted state prior to sawing the workpiece, such that the cutting edge of the saw band  34  encloses a sharp angle with the transport surface of the saw table  10 . Subsequently, the method comprises moving the saw assembly  30  downward during sawing, such that the cutting edge of the saw band  34  saws the workpiece. During a start and middle phase of the sawing, the actuator of the blocking element control assembly  56  is not in contact with the stop connected to the saw frame  32  and the blocking element control assembly  56  keeps the blocking element  54  in the blocking state. During an end phase of the sawing the actuator of the blocking element control assembly  56  is in contact with the stop connected to the saw frame  32  and the blocking element control assembly  56  brings the blocking element  54  in a deblocking state. Thereupon, the guiding assembly  48  and the saw assembly motor  36  cooperate to transfer the saw assembly  30  from a tilted to a non-tilted state. 
     The various embodiments which are described above may be used independently from one another or may be combined with one another in any combination. The reference numbers used in the detailed description and the claims do not limit the description of the embodiments nor do they limit the claims. The reference numbers are solely used to clarify. 
     LEGEND 
       10 —saw table 
       12 —saw table frame 
       14 —transport roller 
       16   a —first longitudinal side 
       16   b —second longitudinal side 
       18 —workpiece support elements 
       20 —band saw workrange 
       20   a —upstream band saw workrange part 
       20   b —downstream band saw workrange part 
       22 —recess 
       24 —band saw apparatus 
       26 —swivel frame 
       28 —support frame 
       30 —saw assembly 
       32 —saw frame 
       33 —saw band driving motor 
       34 —saw band 
       36 —saw assembly driving motor 
       38 —saw list 
       38   a —upstream saw list 
       38   b —downstream saw list 
       42 —backstop 
       44 —workpiece-clamp 
       46 —workpiece-clamp guiding rail 
       48 —guiding assembly 
       50   a —first guiding rail 
       50   b —second guiding rail 
       52 —guiding element 
       54 —blocking element 
       56 —blocking element control assembly 
     N—neutral plane 
     C—vertical centreline