Abstract:
The present invention is a lightweight collapsible hand saw for use when camping, hiking or otherwise. The saw breaks down and can be consolidated into a single tubular shape, with all of the components fitting inside the tube. In the functional configuration, a triangular saw may be constructed out of two tubular members having different diameters, a saw blade and a tightening element. Alternatively, both a triangular saw and a buck saw may be constructed out of three tubular members having different diameters, a saw blade and a tightening element. The tubular members form the frame of the saw and contain slots for inserting the saw blade. The tightening element is provided to give the saw the necessary rigidity and impart the necessary tension on the blade. In addition, the apparatus can be used to form a campfire cooking utensil with a number of accessorising elements.

Description:
RELATED APPLICATION 
     The invention herein disclosed is related to the Swiss patent application number 1997 1930/97, filed Aug. 18 1997, and claims priority on that application. 
     FIELD OF THE INVENTION 
     The invention relates to a hand saw. Specifically, the invention is a portable, lightweight, collapsible hand saw that can be used as a triangular or buck saw and may further be converted into a campfire cooking utensil with the addition of a number of accessories. 
     BACKGROUND OF THE INVENTION 
     The prior art in hand saws includes three basic designs. The first and most common design involves a saw with a rigid frame in which the blade is tensioned at the ends so as to secure it in place. This type of saw is the most common variety of hand saw used for domestic and industrial purposes. The drawback with the rigid frame saw is that the blade is always exposed and the saw is not collapsible. Consequently, rigid frame saws are ideal for domestic and industrial use where portability is not required. 
     The second hand saw design involves a hand saw frame which includes hinges and can be folded and compacted via the hinge mechanism. The hinged frame provides for a hand saw that can be somewhat compact and portable. U.S. Pat. Nos. 4,580,344 (issued to Jinghage et al.), 3,905,409 (issued to Bradley), and 3,954,127 (issued to Doxon) disclose hinged frame saws. The Jinghage and Bradley saws are foldable triangular saws and the Doxon saw is a foldable bow saw. The Jinghage, Bradley and Doxon designs suffer from the typical drawbacks associated with hinged frame saws. The disadvantages include: 
     (i) the saws are relatively wide, making them more cumbersome, because the parts of a hinged saw frame fold in on one another and so must accommodate the other parts of the saw; 
     (ii) hinged saws are generally restricted to light duty saws, because they lack the sturdiness and rigidity required for a heavy duty sawing, particularly in the hinge region, which is under a great deal of stress; and 
     (iii) the addition of the hinge increases the overall weight, reducing the saw&#39;s portability. 
     The third hand saw design involves frames that are assembled from separate or severable components and are collapsible so as to remain easily portable. Once again, these designs are principally used for buck saws or triangular saws. 
     U.S. Pat. Nos. 4,287,922 (issued to Nelson), 4,186,785 (issued to Bilsback)and Canadian Patent No. 889,673 (issued to Moss). concern collapsible buck saws made from separate or severable parts. For these patents, the saw design includes a collapsed state, wherein all of the buck saw parts fit into the interior of the hollow tubular frame members, making the collapsed assembly easily portable. 
     Nelson discloses a buck saw having a single tubular cross member, with two pairs of support bars hinged onto the saw blade and shaped so as to slide perpendicularly through openings in the cross member. The Nelson apparatus is tensioned only by a loop of twine, which secures the support bars. Although the twine tension mechanism is extremely lightweight, the tension achievable in the Nelson design, is severely limited. Furthermore, the support bars provided for by the Nelson saw are not comfortable hand grips. These disadvantages make the Nelson buck saw suitable for only the most light duty sawing. 
     Bilsback discloses a buck saw that also has two tubular support bars, which form the handles of the saw when constructed. The support bars each have slots at one end that receive the saw blade. A rod shaped tensioner and a tubular cross members provide the support and tension for the apparatus. The cross member, is pushed into an aperture in the middle of each of the support bars and is used to maintain the separation of the support bars. The tensioner is located at the end of the support bars opposite to the saw blade. The tensioner, in combination with two thumb nuts, is operative to pull the support bars together and to exert outward tension on the saw blade. The problems with Bilsback include: 
     (i) the saw blade requires washers, which are attached to the blade by rivets. Over time, the washers can become worn and break or bend; 
     (ii) the thumb nuts could easily become lost on a hiking trip, rendering the saw useless; 
     (iii) the Bilsback saw has poor vertical clearance between the saw blade and the cross member; and 
     (iv) in the compact mode, the thumb nuts on either side of the compacted tube add to its overall length. 
     The Moss saw uses a large support bar with a closed end that is longer than all of the other saw elements including the saw blade. In the collapsed configuration, all of the elements of the Moss saw are longitudinally inserted into the large support bar. A smaller support bar with a closed end is slidably inserted into the large support bar and fastened with a small clip. In the functional configuration, the saw includes a tensioner that goes through one of the support bars and hooks to the second support bar of the saw, and puts the necessary tension on the saw blade. The disadvantages with the Moss saw include: 
     (i) the large support bar is very long and heavy (even in the collapsed configuration) because it must contain all of the other saw elements consequently, the support bar extends below the saw blade limiting the use of the saw, particularly for making flush cuts; 
     (ii) the clip used to maintain the saw in the collapsed configuration may become easily lost; and 
     (iii) the support bars have flat ends which are not shaped to be received by the handles; consequently, the frame is not very rigid and the saw blade may experience considerable torque because of the twisting frame. 
     U.S. Pat. Nos. 3,905,409 (issued to Bradley) and 4,637,141 (issued to Allen) disclose collapsible triangular saws. Once again, the saws are collapsible so that all of the saw parts for each saw fit into a singular tubular shape that is also used to form part of its frame. 
     The Bradley saw is partially collapsible and partially hinged. The saw blade is attached to a brace bar with a special hook, such that it can be positioned at an angle with respect to the brace bar when in the functional configuration. One end of a tubular handle adjoins the brace bar at the side opposite the saw blade and forms a perpendicular angle therewith. The bottom end of the tubular handle is coupled to the second end of the saw blade with a hinged thumb screw/butterfly nut assembly. In this manner, the saw blade, brace bar and tubular handle form a functional triangular saw. When in storage mode, the brace bar and the saw blade slide longitudinally into the tubular handle. The thumbscrew/butterfly nut assembly is then used to secure the pieces in place so that the saw may be easily transported. The problems with the Bradley design include: 
     (i) the thumb screw/butterfly nut assembly adds extra length to the collapsed state; 
     (ii) the possibility for the thumbscrew/butterfly nut assembly to become lost; and 
     (iii) the lack of strength in the relatively flat brace bar. 
     The Allen saw consists of two tubular pieces of different diameter such that one fits longitudinally into the other when in storage configuration. Each of the two tubes contains a slot at one end which is operative to hold the saw blade when the saw in is a functional configuration. In the functional configuration, the non-slotted end of the thin tube abuts against the cylindrical side wall of the wider diameter tube at a substantially perpendicular orientation. The saw blade is held in the saw blade slots at the opposite ends of the two tubular pieces. A tensioning device comprising a screw with a hook on one end and a thumb nut is then used to exert tension on the saw blade. The hook of the tensioning screw fits into a hole on the cylindrical side wall of the thin tube and the shaft of the tensioning screw pushes through two holes in the cylindrical side walls of the wider tube, where it engages the thumb nut. In the compact configuration, the saw blade slides longitudinally into the thin tube, which, in turn, slides longitudinally into the wider tube. The hooked end of the tensioning device also slides into the tube assembly, leaving the shaft of the tensioning screw pushing through the circular end of the wide tube where it engages the thumb nut, and operates to hold the compact apparatus closed. 
     The problems with the Allen design are best illustrated with reference to the figures in that patent document. FIGS. 8 and 9 depict the tensioning screw  18  with its shaft having a straight piece  90  with threads  98  and a bent section  96  with a hook  94 . In FIG. 1, the saw is shown in its functional configuration. The problem with the design is that, while exerting sufficient force in the horizontal direction (i.e. along the thin tube  50 ), the tensioning screw exerts relatively little force in the vertical direction (i.e. along the wide tube  12 ). The slotted end  68  of the thin tube  50  is susceptible to being vertically displaced during a sawing motion. Consequently, the saw is not sufficiently rigid for heavy duty sawing applications and may break or come apart, subjecting the user to unnecessary danger. 
     A second disadvantage of the Allen design is the extra length of the compacted configuration that is required to accommodate the thumb nut of the tensioning device. 
     A final disadvantage with the Allen design is that the thumb nut of the tensioning device may be easily lost, particularly in the wilderness, rendering the device useless 
     In view of the foregoing disadvantages inherent in the known types of collapsible hand saws as taught in the prior art, the present invention serves a number of objectives. 
     It is a primary object of the present invention to provide a lightweight and portable saw that is collapsible into a single tubular shape, but may be configured to function as a triangular saw or both a triangular saw and a buck saw. These alternative configuration modes permit the apparatus herein disclosed to be used for both triangular saw applications (i.e. when there is limited room or a stronger saw is needed and when clearance between the blade and the top support bar is not important) and buck saw applications, which require a substantial clearance between the blade and the top support bar. 
     A second object of the present invention is to provide a saw without unnecessary torque on the saw blade that could cause the saw blade to break and possibly put the user&#39;s safety in jeopardy. 
     Another object of the present invention is to provide for a lightweight portable saw that may be converted easily into an outdoor cooking utensil with the addition of some simple accessories. 
     Another object of the present invention is to provide an apparatus which is stable, as small as possible, has the fewest number of pieces, has no small parts which may be easily lost and is lightweight, so that it may be easily carried while hiking or working outdoors on a tool-belt or a backpack. 
     Another object of the present invention is to provide an apparatus which is easily assemblable and dissassemblable into any of its various configurations. 
     SUMMARY OF THE INVENTION 
     The invention herein disclosed concerns an apparatus for a lightweight collapsible hand saw. The hand saw apparatus comprises two hollow tubular members, a first of which is longer and has a smaller diameter than the second, and the second being shorter and wider, such that the first tubular member is longitudinally insertable into the interior of the second. The apparatus also includes at least one saw blade that is couplable at each end to a corresponding one end of the first and second tubes and a tightening element that is couplable at each end to a corresponding one of the first and second tubular members on a cylindrical side wall or a circular end thereof. 
     The tightening element is comprised of a single non-severable assembly. Both the tightening element and the saw blades are longitudinally insertable into the interior of the first tubular member. The second tubular member has an opening in the middle of its cylindrical side wall which is operative to receive an end of the first tubular members, such that when the tubular members are joined in this manner, they are oriented substantially perpendicular. 
     The saw blade, tightening element and the two tubular members are couplable to one another so as to form a triangular saw configuration. In the triangular saw configuration, the proximate end of the first tubular member is inserted into the opening in the cylindrical side wall of the second tubular member. The saw blade then extends between a first bottom end of the second tubular member and the distal end of the first tubular member, and similarly, the tightening element extends between a second upper end of the second tubular member and the distal end of the first tubular member. The tightening element is operative to provide tension to the triangular saw configuration both in a direction parallel to the first tubular member and in a direction parallel to the second tubular member. 
     The saw blade, tightening element and the two tubular members are insertable into one another, so as to compact into a singular tube shaped storage configuration that is non-cumbersome and easily portable. 
     The first tubular member may include a reduced diameter section at the proximate end to aid in fitting snugly into the opening of the second tubular member. Advantageously, the proximate end of the first tubular member may be formed in a half-round shape, so as to abut against and conform to the inner cylindrical wall of the second tubular member when inserted into the opening therein. The half-round shape is operative to substantially reduce the torque on both the saw frame and the saw blade. 
     The first and second tubular members may each include a slot in at least one end, which slot is operative to receive and secure an end of the saw blade. Preferably, distal end of the first tubular member may include a depression surrounding the slot in the cylindrical side wall of thereof, which is operative to further secure an end of the saw blade. The distal end of the first tubular member may also have a closing disk located within the tube, at a location coinciding with the depression. The closing disk may be operative to close off said distal end of said first tubular member, except for a slot which allows clearance for said saw blade. 
     The second tubular member may also be closed at the second upper end, but the upper end may comprise a plurality of small holes operative to receive an end of the tightening element, to receive a fixing element and to receive a rubber buffer. 
     Advantageously, the first and second tubular members may contain a plurality of holes in the cylindrical side walls and on the ends thereof. The holes may be operative to receive an end of the tightening element. The tightening element may contain at hook at each end thereof. The hooks may be operative to secure the ends of the tightening element in the holes. The tightening element may also include an adjustment mechanism for changing the overall length of the tightening element. 
     The saw blade may include a cam at both ends which is operative to secure the saw blade in the slots of the first and second tubular members. 
     Preferably, the first tubular member may contain a protruding tongue and the second tubular member may contain an elongated opening, such that when the first tubular member is longitudinally inserted into the second, the tongue is operative to fit into the elongated opening and lock the tubular members together in the tube shaped storage configuration. 
     One of the first and second tubular members may include a fixing element operative to provide an easy attachment to the apparatus when in the tube shaped storage configuration. 
     The saw blade may be removed from the triangular saw configuration of the apparatus, and the apparatus may form an outdoor cooking utensil operative to hold a cooking vessel over a heat source. The cooking vessel may be a pot, kettle, grill or rotisserie. 
     Another aspect of this invention involves an apparatus for a lightweight collapsible hand saw comprising three hollow tubular members of various lengths and widths. The first tubular member is the longest and thinnest, the second tubular member is shorter with a medium diameter and the third is also short and has the largest diameter. The, three tubular members slide longitudinally into the interior of one another. Furthermore, the second and third tubular members include openings in the cylindrical side walls thereof. The openings are operative to receive the ends of the first tubular member which can be inserted into the openings so as to form a substantially right angle. The apparatus also comprises a saw blade which is couplable at each end to a corresponding one of the first, second and third tubular members and can slide longitudinally into the interior of the first tubular member. Finally, the apparatus includes a tightening element that is couplable at each end to a corresponding one of the first, second and third tubular members. The tightening element is couplable to the tubular members on the circular ends or the cylindrical side walls thereof and can slide longitudinally into the interior of the first tubular member. 
     The saw blade, tightening element and the three tubular members are longitudinally insertable into one another so as to compact into a singular tube shaped storage configuration which is non-cumbersome and easily portable. The saw blade, tightening element and the three tubular members are also couplable to one another so as to form a triangular saw configuration and a buck saw configuration. 
     The saw blade, tightening element and two of the three tubular members may be configured so as to form a triangular saw. 
     The first tubular member may include a reduced diameter section at a first end to aid in fitting snugly into the opening of the second tubular member. The first tubular member may have both of its ends shaped so as to conform to the inner cylindrical walls of the second and third tubular members when inserted into the openings therein. The half round shape may be operative to substantially reduce the torque experienced by the saw frame and the saw blade when in the triangular saw or the buck saw configuration. 
     Each of the three tubular members may contain a slot in at least one end which is operative to receive and secure an end of the saw blade. Preferably, one end of the first tubular member may include a depression surrounding the slot in the cylindrical side wall of thereof, which is operative to further secure an end of the saw blade. 
     The second and third tubular members may be closed at one end, but the closed ends may contain a plurality of small holes operative to receive an end of the tightening element, to receive a fixing element and to receive a rubber buffer. Alternatively or in addition, the first, second and third tubular members may contain holes in the cylindrical side walls or on the ends thereof, which are operative to receive the ends of the tightening element. The tightening element may contain at hook at each end. The hooks may be operative to secure the ends of the tightening element in the holes. The tightening element may also include an adjustment mechanism for changing the overall length of the tightening element. 
     The saw blade may include a cam at each end which is operative to secure the ends of the saw blade in the slots of the tubular members. 
     Preferably, the second tubular member may contain a protruding tongue and the third tubular member may contain an elongated opening, such that when the second tubular member is longitudinally inserted into the third, the tongue is operative to fit into the elongated opening and lock the tubular members together in the tube shaped storage configuration. 
     The second tubular member may include a rubber buffer at one end, such that the second tubular member fits snugly when longitudinally inserted into said third tubular member. 
     One of the second or third tubular members may also include a fixing element which facilitates easy coupling to the apparatus when it is in the tube shaped storage configuration. 
     The saw blade may be removed from the apparatus and an earth pin may be added to the apparatus. The earth pin may be partially insertable into the one of the second or third tubular members and is operative to secure the apparatus such that it may stand freely in the ground. The earth pin may allow the apparatus to be configured as a vertically adjustable and pivotable outdoor cooking utensil operative to hold a cooking vessel over a heat source. The vertically adjustable and pivotable outdoor cooking utensil may further comprise a cooking vessel chosen from the group of: a pot, a kettle, a grill, and a rotisserie. 
     A third aspect of this invention involves an apparatus for a lightweight collapsible hand saw comprising three hollow tubular members of various lengths and widths. The first tubular member is the longest and thinnest, the second tubular member is shorter with a medium diameter and the third is also short and has the largest diameter. The three tubular members slide longitudinally into the interior of one another. Furthermore, the second and third tubular members include openings in the cylindrical side walls thereof. The openings are operative to receive the ends of the first tubular member which can be inserted into the openings so as to form a substantially right angle. The apparatus also comprises a saw blade which is couplable at each end to a corresponding one of the first, second and third tubular members and can slide longitudinally into the interior of the first tubular member. Finally, the apparatus includes a tightening element that is couplable at each end to a corresponding one of the first, second and third tubular members. The tightening element is couplable to the tubular members on the circular ends or the cylindrical side walls thereof and can slide longitudinally into the interior of the first tubular member. 
     The saw blade, tightening element and the three tubular members are longitudinally insertable into one another so as to compact into a singular tube shaped storage configuration which is non-cumbersome and easily portable. The saw blade, tightening element and the three tubular members are also couplable to one another so as to form a buck saw configuration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 depicts the second embodiment of the apparatus in the triangular saw configuration. 
     FIG. 2 depicts the second embodiment of the apparatus in the buck saw configuration. 
     FIG. 3 depicts the separate parts of the second embodiment of the apparatus. 
     FIG. 4 depicts the second embodiment of the apparatus in the portable storage configuration wherein all of the saw parts are enclosed within a tubular portion of the saw frame. 
     FIG. 5 shows how the second embodiment of the apparatus can be configured into an outdoor cooking utensil with the addition of some simple accessories. 
     FIG. 6 a  depicts a side view of the ends of the thin tube  1  in the second embodiment. FIG. 6 b  depicts a top view of the ends of the thin tube  1  in the second embodiment. 
     FIG. 7 a  depicts a side view of the ends of the thin tube  1  in the second embodiment. FIG. 7 b  depicts a top view of the ends of the thin tube  1  in the second embodiment. 
     FIG. 8 depicts the separate parts of the first embodiment. 
     FIG. 9 depicts the first embodiment of the apparatus in the triangular saw configuration. 
     FIG. 10 depicts a front view of the end plate. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the FIGS. 1 through 9 the collapsible and portable hand saw system embodying the principles and concepts of the present invention is hereinafter described. 
     The First Embodiment 
     FIG. 8 depicts the parts of the first embodiment when disassembled. The apparatus of the first embodiment includes two tubular members  1  and  2  having different diameters, a saw blade  6  and a tightening element  8 . The apparatus is normally arranged in one of two configurations; a compacted configuration used for carrying the device and a functional configuration used for a triangular saw. 
     Tube  1  has the smallest diameter, but, being approximately the length of the saw blade  6 , is the longest of the tubular members. Tube  1  includes holes  22  for coupling to the tightening element  8  and a slot  5  at one end  26  for insertion of the saw blade  6 . The slotted end  26  also includes a depression  28  which is used to assist in bracing the saw blade in the slot. At the opposing end  25  of tube  1 , the diameter is reduced in a small section  23  and the end  25  is shaped in a “half-round” form so as to conform to the inner diameter of the shorter tube  2  for coupling thereto. The half-round shaped end  25  includes two convex sections, which are bisected by the plane of the slot  5 . This orientation of the slot  5  with the convex ends is integral to reducing the lateral torque on the saw blade when the apparatus is in a functional configuration. Tube  1  also includes a tongue  20  used to couple it to tube  2  when in the compacted configuration. Tube  1  also includes a closing disk  27  inserted into one end of the tube, so as to contain the saw parts in the compacted configuration. 
     Tube  2  is the shorter and wider of the two tubes and includes a round end plate  13  which closes it on one side. The end plate  13  has a hole  12  that is operative to receive the hooks  10  of the tightening element  8 . The short tube  2  may alternatively include holes (not shown) for mounting the tightening element  8  on the cylindrical side wall of the tube, such that end plate  13  could be completely closed. A further hole (not shown) may be included in the end plate  13  for attaching a fixing element (not shown) so that the device may be easily coupled to a backpack or tool belt. A rubber buffer  16  is also inserted into the end of tube  2  and attaches to end plate  13 . The buffer  16  is operative to reduce the rattling and provide some elasticity to the closure mechanism when the apparatus is in the compact configuration. At the opposing end from the end plate  13 , the shorter tube  2  includes a slot  42  for insertion of the saw blade  6 . Near the center of the short tube  2 , in the same plane as slot  42 , is an opening  4  on the cylindrical side wall of the tube. The opening is sized and shaped to receive the reduced diameter end  25  of the thinnest tube  1 . The opening  4  also has a rounded extension  14 , which serves as a lock opening, receiving the tongue  20  from the tube  1 , so as to keep the apparatus fastened together when in the storage configuration. 
     The saw blade  6  comprises two cams  7  positioned at each end, which are used to secure the blade  6  in the slots  5  and  42  of tubes  1  and  2  respectively. A plurality of saw blades may be included in the apparatus for various types of sawing applications. 
     The tightening element  8  is comprised of two threaded bars, the outer ends of which are formed into hooks  10 . Also included in the tightening element  8  is the adjustment mechanism  9 , which is used to adjust the overall length of the tightening element  8 . The threaded bars are notched at the inner ends (not shown) so that the adjustment mechanism  9  can not be completely separated from the tightening element  8 , reducing the chances the pieces of the tightening element could be accidentally lost. 
     FIG. 9 depicts the first embodiment of the apparatus in the triangular saw configuration. The reduced diameter end  25  of long tube  1  is plugged into the opening  4  of tube  2  in such a way that the slot  5  at the distal end  26  of tube  1  is oriented parallel with the slot  42  in tube  2 . The saw blade  6  is inserted into the slots  5  and  42  of tube  1  and  2  respectively and is secured in place by tightening element  8 , which is fitted into the hole  22  of the long tube  1  and in the hole  12  in the end plate  13  of tube  2 . Tube  2  then becomes a handle and is used as a regular triangular saw by moving blade  6  back and forth across the surface to be cut (not shown). 
     An important aspect of the invention is depicted in FIGS. 7 a  and  7   b  that show how the slot  5  of the slotted end  26  is aligned with the half round end  25  of tube  1 . The half round end  25  has two convex portions  29  and two concave portions  30 . The alignment of the convex portions  29  so that they are bisected by the plane of the slot  5  is crucial to ensure that the half-round end  25  fits snugly against the inner cylindrical wall of tube  2  (not shown). This orientation substantially reduces the lateral torque on the saw blade (not shown). 
     Referring back to FIG. 9, the saw can be configured as a campfire cooking utensil by removing the saw blade  6  and fixing tube  2  vertically. This leaves tube  1  substantially horizontal where it can extend over a heat source (not shown). A pot with a wire handle can then be hung over the heat source from the extended portion of tube  1 . 
     Referring now to FIG. 8 again, to put the apparatus in the compact configuration, the saw blade  6  and the tightening element  8  are inserted longitudinally into the open end  25  of tube  1 . The open end  25  of tube  1  is then inserted longitudinally into tube  2 . The tongue  20  on tube  1  and the elongated opening  14  on tube  2  provide a locking mechanism which locks the compacted assembly together. The tongue  20  extends outward from the tube  1 . Pressure from the saw blade  6  and the rubber buffer  16 , provide the necessary elasticity to ensure that the locking mechanism engages. To unlock the assembly, tongue  20  must be pushed back into the tube and then tube  1  may be slid out from within tube  2 . 
     The Second Embodiment 
     FIG. 3 shows the parts of the second embodiment when disassembled. The apparatus according to the invention includes three tubular members  1 ,  2 , and  3  having different diameters, a saw blade  6  and a tightening element  8 . 
     Tube  1  has the smallest diameter, but, being approximately the length of the saw blade  6 , is the longest of the three tubular members. Tube  1  includes a hole  22  for coupling to tightening element  8  and a slot  5  at one end for insertion of the saw blade  6 . One of the slotted ends  24  also includes a depression  28  used to assist in bracing the saw blade  6  in the slot  5 . At the opposing end  25  of tube  1 , the diameter is reduced in a small section  23  for coupling to the medium sized tube  2 . The ends of the tube  1  are formed in a “half-round” shape so as to conform to the inner diameters of the shorter tubes  2  and  3  for the purpose of coupling thereto. The half-round shapes include two convex sections, which are bisected by the plane of slot  5 . This orientation of slot  5  with the convex ends is integral to reducing the torque on the saw blade when the apparatus is in a functional configuration. Tube  1  also contains several other holes  22  in the cylindrical side wall thereof, for use in coupling to the tightening element and for a campfire cooking utensil. 
     Tubes  2  and  3  are the shorter tubes and each includes a round end plates  13  and  46  respectively which closes them on one side. The end plates  13  and  46  may have a hole  12  in each, which is operative to receive the hooks  10  of the tightening element  8 . The short tubes  2  and  3  may alternatively include holes  19  for mounting the tightening element  8  on the cylindrical side wall of the tubes, such that end plates  13  and  46  on the ends of the short tubes  2  and  3  respectively could be completely closed. A further hole may be included in the end plates  13  and  46  to serve for the reception of a fixing element  17  or the rubber buffer  16 . The buffer  16  is operative to reduce the rattling and provide some elasticity to the closure of the apparatus when it is in the compact configuration. The buffer  16  is inserted into the closed end of tube  2  and attached to the end plate  13 . At the opposing end from the round plates  13  and  46 , the shorter tubes  2  and  3  include slots  42  and  44  respectively for insertion of the saw blade  6 . Near the center of the short tubes  2  and  3  are openings  4  and  48  respectively on the cylindrical side wall of the respective tubes. The openings  4  and  48  are sized and shaped to receive the ends ( 25  and  24 ) of the thinnest tube  1 . Another feature on the cylindrical side walls of tube  3  are the holes  19  which are used for the height adjustment mechanism for the campfire cooking utensil. 
     Tube  2  includes tongue  20  on its cylindrical side wall, while the opening  48  of tube  3  includes a rounded extension  14 , which serves as a lock opening, receiving the tongue  20  from tube  2 . The tongue  20  engages the extension  14  so as to keep the parts of the saw fastened together when in the storage configuration. 
     The saw blade  6  comprises two cams  7  positioned at each end which are used to secure the blade  6  in the slots  5 ,  42  and  44  of tubes  1 ,  2  and  3  respectively. A plurality of saw blades may be included in the apparatus for various types of sawing applications. 
     The tightening element  8  is comprised of two threaded bars, the outer ends of which are formed into hooks  10 . Also included in the tightening element  8  is the adjustment mechanism  9 , which is used to adjust the overall length of the tightening element  8 . The threaded bars are notched at the inner ends (not shown) so that the adjustment mechanism  9  can not be completely separated from the tightening element  8 , reducing the possibility that the pieces of the tightening element could be accidentally lost. 
     In connecting with one another, the long tube  1  may be slotted into either, or both, of the openings  4  and  48  in the cylindrical side walls of the shorter tubes  2  and  3  respectively. The small diameter end  25  of tube  1  is insertable into tube  2 , while the wider end  24  of tube  1  is insertable into the widest tube  3 . The bump  21  on the wide end  24  of tube  1  ensures that the wide end will only fit into the opening  48  of tube  3 , which has the rounded extension  14 . The “half-round” ends of the long tube  1  abut directly against the inner cylindrical side walls of the wider tubes  2  and  3 . The saw blade  6  is insertable into the slots  5 ,  42  and  44  of tubes  1 ,  2  and  3  respectively and the hooks  10  of the tightening element  8  may be inserted into holes in the end plates  13  and  46  of tubes  2  and  3  respectively or the cylindrical side walls of the tubes  22 . 
     FIG. 1 depicts the apparatus in the triangular saw configuration. The short tube  2 , having the medium sized diameter, is pushed into the widest tube  3  in such a manner that the openings  4  and  48  in the cylindrical side walls of both tube  2  and  3  are aligned, as are the slots  5   42  and  44  in tubes  2  and  3  respectively. Thereafter, the small diameter end  25  of long tube  1  is plugged into the opening  48  in such a way that the slot  5  at the distal end of tube  1  is oriented parallel to the slots  42  and  44  of tubes  2  and  3 . The saw blade  6  is inserted into the slots  5 ,  42  and  44  and is secured in place by tightening element  8  which is fitted into the hole  22  of the long tube  1  and in the hole  12  of the short tube  3 . The saw may then be gripped at handle  3  and used as a regular triangular saw by moving the blade  6  back and forth across the surface to be cut (not shown). An alternative configuration may be easily conceived of, wherein the largest diameter tube  3  is not used at all, and tube  2  is the only one used for the handle of the saw. 
     FIG. 2 depicts the buck saw configuration of the invention. Each end of the long tube  1  is inserted into one of the openings  4  and  48  of the short tubes  2  and  3  respectively. The blade  6  is inserted in slots  42  and  44  of tubes  2  and  3  respectively. The hooks  10  of the tightening element  8  can then be inserted into holes  12  and the entire assembly can be tightened with the adjusting mechanism  9  until the necessary rigidity and sturdiness are achieved. The buck saw may then be gripped by one or two individuals at handles  2  and  3  and used as a regular buck saw by moving blade  6  across a surface. 
     An important aspect of the invention is depicted in FIGS. 6 a  and  6   b  that show how the slot  5  is aligned with the half round ends of tube  1 . The half round ends have two convex portions  29  and two concave portions  30 . The alignment of the convex portions  29  so that they are bisected by the plane of the slot  5  is crucial to ensure that the half-round ends fit snugly against the inner cylindrical wall of tubes  2  and  3  (not shown). This orientation substantially reduces the lateral torque on the saw blade (not shown). 
     FIG. 5 depicts the method in which the apparatus can be configured as an outdoor cooking utensil with the addition of a few simple accessories. At least two additional holes  22  are provided in the longest tube  1  for attaching the grill attachments  31  which are hinged to the actual grill  18 . The accessory package may include the grill  18 , a water pot (not shown), a pan (not shown), a hot plate (not shown) and other cooking utensils (not shown), which can be fit together for easy portability. The tubular members of the apparatus are configured as in the buck saw; however, the saw blade  6  (not shown in FIG. 5) is not included. Furthermore, tubes  2  and  3  are not inserted all the way into one another. The medium width tube  2  is inserted a short distance into the widest tube  3 , the distance of penetration (and hence, the height of the apparatus above the heat source) being controlled by additional holes  19  in tube  3  and the button  11  (see FIG. 3) on tube  2 . The button  11  is positioned next to the rubber buffer  16  in tube  2  so that when depressed it is biased to return to an extended position by the rubber buffer  16 , ensuring a secure lock into the holes  19  of tube  3 . An earth pin  40  with a plug at the end of it is inserted into tube  2  and is anchored into the ground to support the entire apparatus. The apparatus configured in this fashion provides for an adjustable height outdoor cooking utensil. 
     FIG. 4 depicts the apparatus in its storage or compacted configuration. In order to fit all of the parts together into a single tubular shape, the tightening element  8  and the saw blade  6  must first be inserted into the interior of the long and thin tube  1 . One end of the long tube  1  is then inserted into the medium diameter tube  2  while the opposite end of the long tube  1  is inserted into the largest diameter tube  3  in such a manner that tubes  2  and  3  enclose tube  1 . Tube  2  meets tube  3  at the center and is inserted into tube  3  a short distance. The outer short tubes  2  and  3  include a locking mechanism which connects them together. The locking mechanism includes a tongue  20  on the medium width tube  2  which fits into the rounded elongation  14  of the opening  48  on the outer cylindrical wall of the widest tube  3 . The tongue  20  extends outward and locks the two short tubes  2  and  3  into place. To unlock the assembly, the tongue  20  must be pushed back into the assembly and then tube  2  may be slid out from within tube  3 . Twine  17  may be used to mount the apparatus onto a backpack. 
     A hand saw having such versatile applications can be helpful for a hiker, a boy scout, a forest ranger, a hunter, a camper and all those needing a lightweight portable hand saw. 
     The foregoing is considered illustrative only of the principles of the invention and numerous modifications and changes will occur readily to those skilled in the art. Consequently, it is not desired to limit the invention to the exact construction and operation shown and described.