Abstract:
A lightweight, collapsible compact platform for use by hikers and backpackers includes a supporting surface having horizontal adjustability. The platform can be conveniently folded into a compact carrying unit less than 6 ounces in weight and having a fold down or compactability ratio of at least approximately 25 to 1. The supporting surface cooperates with vertical legs that can be adjusted to provide a level supporting surface irrespective of the slope of the underlying ground surface.

Description:
This application claims benefit of Provisional Application Ser. No. 60/055,062 filed Aug. 8, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to leveling platforms and more particularly to a backpacking table adapted to provide a stable and level or horizontal surface irrespective of the slope of the underlying ground surface. 
     2. Description of Related Art 
     Backpacking places various demands and constraints on equipment utilized because there is a limit as to what can be carried by an individual. Compactness and weight are two of the more important constraints. Thus, backpacking equipment is generally required to be lightweight and of a size that can be conveniently accommodated in a backpack. 
     Because the terrain to which backpackers are attracted is seldom level, there is a need to provide a stable and level platform for accommodating various needs. Such might be accomplished by a flat substrate with legs which are readily adjustable to provide a substantially horizontal or level supporting surface irrespective of the slope of the underlying ground surface. Such a surface could be utilized for a variety of purposes, e.g. cooking, eating, and effecting equipment repairs, but would not necessarily address the problem of size and weight. 
     Backpacking stoves are sometimes provided with adjustable legs which provide a small degree of leveling adjustment, but such legs do little for stability, particularly with respect to steep sloping surfaces. There are also products that improve the stability of some stoves, but do not provide a leveling capability. 
     SUMMARY OF THE INVENTION 
     The subject invention overcomes the aforenoted deficiencies and provides a platform having a good leveling capability, coupled with increased stability, a supporting surface having a horizontal adjustability to fit many stoves and most important is small in size and light in weight and which can be conveniently folded into a compact carrying unit. 
     It is a primary object of the present invention to provide a platform which can be adjusted to provide a level supporting surface irrespective of the slope of the underlying ground surface. 
     Another object of the present invention is to provide a lightweight and compact table readily adapted for use by backpackers. 
     A further object of the present invention is to provide a lightweight compact collapsible table having a high ratio of compactability. 
     These objects and their attendant advantages are accomplished by the present invention by a three member adjustable-size triangular body and an integral slide, with independently vertically adjustable leg members adapted to be folded into the members to provide a compact unit less than 6 ounces in weight and adapted to be carried in a backpack. 
     In accordance with one feature of the invention there is provided a leveling platform having a fold down or compactability ratio of at least approximately 25 to 1. Compactability ratio is defined as the volume occupied by the platform within its maximum external dimensions when in use compared to the volume of the platform in its fold down or knock down condition ready for transport. 
     In accordance with yet another feature of the present invention a leveling platform comprises a three-member adjustable-size triangular body and an integral slide on one member, and three independently vertically adjustable legs extending from the corners of the triangular body adapted to set the height and level of the platform over various slopes and contours of the underlying ground surface. 
     In still another feature of the invention, the three legs fold into the body members to provide a compact unit which takes up only about 8% of the volume of the full body with legs extended. 
     In accordance with the present invention, the members of the triangular body include: 
     1. a front fixed member; 
     2. a left pivoting arm member; and 
     3. a right pivoting arm member. 
     The right arm member includes a slot that allows the left arm member to project through it. By rotating the arms and moving the left arm through the right arm, various size triangular shapes of the body can be obtained. 
     Each member is a right angle strut of lightweight metal, such as aluminum, having a flat surface and a vertical wall surface. Objects to be supported rest within the vertical surfaces of the triangular body formed by the three members. By changing the body size and triangular shape various objects of varying sizes can be supported and contained. To fold the members into a compact unit, the left arm member is slid all the way through a slot in a slide on the right arm member, thus bringing the front and right member into an abutting position. The left arm member is then pivoted into position adjacent the abutting members to active a nested or fold down state of the members. In the nested state, the open area within the walls of the three members is collapsed. The right arm member slides under the front member and when the left member is pivoted into its folded position. The vertical walls of the members form two channels into which the leg members are pivotally received. 
     A slide is disposed over a slot in the right arm and includes a slot complimentary to a slot in the right arm. The left arm protrudes through the slots and a lock mechanism, such as, for example a bolt is used to lock the left arm and the right arm together and to lock the selected triangular shape. 
     Two adjustable-length legs are slidably contained within two holes at opposite ends of the front member and a third leg is slidably contained in one hole in the slide. The legs are C-shaped with a front slit forming a channel. A threaded nut slides within the channel of each leg and a bolt extends through a hole in an end-tab located at an end of the associated member and is threaded into the nut within the leg. When the screw is tightened the leg is held against the associated member. When the screw is loosened the leg can be slipped through the hole and its height composition relative to the platform can be adjusted. At the desired height, the bolt is again tightened to maintain the desired length. Each leg is independently adjustable to a desired height. 
     As shown in FIGS. 5A,  5 B and  8 , the end-tabs  61 ,  62 , and  71  are disposed on either end of the front member  14  and on a slide  38  arranged to operatively slide along the right member  16 . FIG. 5B shows end-tab  61 ,  62  oriented perpendicular to the long length of the associated member  14  and has a hole for receiving the bolt. FIG. 5A shows an alternative embodiment in which end-tab  61 ,  62  is oriented at an angle with respect to the long length of the associated member  14  so that a leg held by a bolt against the end-tab will lean at an angle relative to the body. In this way, the adjustable legs are mounted in the triangular body at slight outward angles to assume an even greater support area, thereby providing increased stability. 
     Stability of the object supported on the body is improved by having the legs located further out from the object than the object&#39;s own supporting mechanism. Additionally, the adjustable legs can be mounted in the triangular body at slight outward angles to assume a greater support area and thereby increased stability. 
     A leg is located in each member and can be rotated at 45° to the perpendicular walls at the ends of the each member and the slide. In this position, the front slit or channel of the leg faces the corner. When the bolt is tightened through the intersection of the perpendicular walls it forces the leg to be supported at its two edges on opposite sides of the slit by the entire height of the two adjacent perpendicular walls. A separate channel piece is included and adapted to press against the outside surfaces of the perpendicular walls through which the bolt projects. The separate channel piece adds additional strength to the walls when the bolt is tightened and provides an operational advantage in folding the leg into its fold position. 
     Two of the legs fold into the front fixed member, one above the other, and the third leg folds into the right arm. A slot extends from each bolt containing hole at the intersection of the perpendicular walls to allow for a 45° rotation of a leg. When the bolt is loosened sufficiently, the leg can be pulled up through the hole in the member and the channel and locking bolt can be rotated into the slot. The leg can then be rotated to lie within one of the channels formed by three members. The leg can be returned to service by reversing this procedure. The channel piece keeps the bolt in place until the bolt is loosened sufficiently to rotate the leg at which point the channel also will slide to the front surface of one of the perpendicular wall members and be locked in place. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and features and their attendant advantages will become more readily apparent to those skilled in the art from the following detailed description of the invention when considered in conjunction with the accompanying drawings. All dimensions shown are in inches. Referring to the drawings: 
     FIG. 1 is a perspective view of the inventive leveling platform mounted on a sloping ground surface with the legs adjusted to provide a level camping stove supporting table. 
     FIG. 2 is a view of the invention in its folded condition. 
     FIG. 2A is a cross-sectional view along lines  2 A— 2 A of FIG.  2 . 
     FIG. 3 is a fragmentary perspective view of the three member adjustable size triangular body which forms the platform of FIG. 1 for supporting objects such as the camping stove shown in FIG.  1  and illustrates in particular the cooperation of the right arm member, the slide and the left arm member which passes through slots in the slide and right arm member. 
     FIG. 4A is a perspective view of the front fixed member shown in FIG. 1 to which the left and right arm members are pivoted. 
     FIG. 4B to a perspective view of on alternate embodiment of the front fixed member. 
     FIG. 5A shows an engineering blank of the front fixed member shown in FIG. 4A with physical dimensions of various parts. 
     FIG. 5B shows an alternate embodiment of an engineering blank of the alternate construction of the front fixed member shown in FIG.  4 B. FIGS. 5-1,  5 - 2  and  5 - 3  show details of punchouts shown in FIG.  5 B. 
     FIG. 6 is a perspective view of the right arm member of the invention shown in FIG.  3 . 
     FIG. 7 shows an engineering blank of the right arm member shown in FIG. 6 showing physical dimensions of various parts. 
     FIG. 8 is a perspective view of the left arm members of the invention shown in FIG.  3 . 
     FIG. 9 is an engineering blank of the left arm member shown in FIG. 8 showing physical dimensions of various parts. 
     FIG. 10 is a perspective view of the slide shown in FIG.  3 . 
     FIG. 11 is an engineering blank of the slide shown in FIG. 9 showing physical dimensions of various parts. 
     FIG. 12 is a perspective view of a leg of the inventive platform showing its inner channel, all legs being identical in shape. 
     FIG. 13 is a cross section view of the leg of FIG. 12 taken along lines  13 — 13 . 
     FIG. 14 is an expanded view of the leg locking mechanism of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, and in particular to FIGS. 1-3, the invention as illustrated comprises a leveling platform  10  including a three member adjustable size triangular body  12  made up of a front member  14 , a right arm member  16  and a left arm member  18 . Each member  14 ,  16 , and  18  has an internal horizontal flat support surface,  15 ,  17  and  19  respectively, and an upward extending right angle wall surface  20 ,  21  and  22 , the inner surface of which helps to contain an object such as stove  24  which rests on the flat supporting surfaces  15 ,  17  and  19 . Stove  24  typically has projections at its lower end which are adapted to be received in slots  26  providing each of the members  14  and  16 . 
     The three members  14 ,  16 , and  18 , when fully extended form a triangular body having a central opening  4 . Camping stove  24 , which may have a rounded portion extending within the opening, but generally supported on the flat surfaces  15 ,  17  and  19 , or their edges, may be further stabilized by extensions (not shown) at the base of the stove adapted to project into slots  26 . If desired, where the object to be supported has a flat base, a flat piece, either solid or mesh, preferably corresponding to the shape of the triangular body may be positioned to rest on the flat surfaces  15 ,  17  and  19  within the adjacent vertical walls to thereby provide a flat table. 
     To maintain the triangular body level, three adjustable legs  28 ,  30  and  32  are contained at the corners of the triangular body when the members are fully extended. The legs are vertically adjustable relative to the body  12  according to the slope and contour of the ground surface  34 . As shown in FIG. 1, the ground slopes from left to right. Thus, leg  32  is locked into the left hand corner of the triangular platform slightly above its mid-point. The ground surface  34  under the right hand corner of the triangular platform as viewed in the drawing is somewhat lower. Thus, the vertical leg  30  extends it full distance and is locked into the corner of the triangular platform formed by members  14  and  16 . Similarly, leg  28  is adjusted for the contour and slope of the ground surface beneath the back corner of the platform  10 . Advantageously, a locking mechanism  36  is provided at opposite ends of the front fixed member  14 , and on slide  38  disposed on right arm member  16 , as more clearly shown in FIG.  3 . 
     At this point, it should be noted that the leveling platform is extremely compact in size having height of approximately 8″. The front arm member extends a distance between the legs  30  and  32  of approximately 9″. The overall length of right arm member  16  is approximately 10″ due to accommodate slide  38  at the end of the arm. Advantageously, the triangular base member is made of a lightweight metal, typically aluminum or the like and weighs less than 6 ounces. As shown in FIG. 2, the unit is adapted to be folded down into a compact package having a length of approximately 10″, a width of 2¼″ and a height of 1¼″, which takes the form of an elongate member. In its folded condition, as shown in FIG. 2, the overall volume of the platform of less than 30 cubic inches, and is fully extended position, or in use position, occupies a volume of approximately 720 cubic inches. Thus, the folding capability of the table gives it a fold down or compactible ratio of approximately 25 to 1, making it extremely desirable for use by backpackers and campers in areas were weight and volume of equipment carried is at a premium. It can be readily appreciated that the platform in its folded condition as shown in FIG. 2 takes up very little space and can be readily and conveniently stored in a backpack. 
     FIG. 3 illustrates the triangular platform  10  in greater detail. To this end, slide  38  is affixed to arm  16  and includes a slot  40  complementary to slot  41  provided in arm  16 . Left arm member  18  passes through the slots  40 ,  41  and when member  16  is extended to provide the desired size opening between the triangular members, the left and right arms are locked together by lock mechanism  42 . Turning of bolt  43  causes the slide  38  to press on the vertical wall  21  of member  16 , which forces edge  44  of the upper rim of slot  41  to press and frictionally engage the upper edge  45  of the vertical wall  22  of arm member  18 . Arm member  18  is pivoted at its lower end at  47  to an extension  48  extending from flat support surface  15  of member  14 . The extension is necessary so that when arm  16  is pivoted against the front member  14 , slot  41  on arm member  16  and the vertical wall  22  passes the vertical axis of pivot  47  to form a channel  23  between walls  20  and  21 , while the lower surface of  17  of member  16  folds in below the lower surface  15  of member  14 . The arms overlay each other with channel being formed between walls  20  and  21  to allow arm  18  to pivot inward adjacent the wall  21  to form a second channel  25  between walls  20  and  21 , as best shown in FIGS. 2 and 2A. 
     The final fold down or collapsed position of the platform  10  is effected by rotating each of the legs into associated channels  23  and  25 . To this end, the adjustable length legs  30  and  32  are contained within two rectangular holes  50  and  52 , respectively in front member  14 . Holes  50  and  52  have axes oblique from the major longitudinal and vertical longitudinal axis of member  14  at angle of 45°. A similar rectangular hole  54  with a 45° oblique axis is provided in slide  38 . Each leg is a channel having a C-shaped cross-section, the channel having a front slit  56  formed so as to enable a threaded nut  57  to be captively retained to slide within the leg channel. A bolt  58  passes through the slit  56  and through a c-shaped channel member  60  and is threaded into the captive nut  57 . The arms of the channel member  60  are adapted to engage on opposite sides of the perpendicular corners of the fixed member  14  and perpendicular corner of slide  38  to lock a leg in place upon tightening of bolt  58 . When bolt  58  is tight, the corresponding leg is held fast against body. When the bolt is loose, the leg can slip through the associated hole ( 50 ,  52 ,  54 ) and can be adjusted to a desired height at which point the bolt is tightened to maintain the height and set the level of the platform. 
     As shown in FIG. 3, legs  30  and  32  are positioned outside the pivot points  47  and  46  and on the outer extremity of front arm  14 , while leg  28  is outside of slots  40 ,  41  to provide maximum stability for the table. 
     As herein before noted, and as shown in FIG. 2A, legs  30 ,  32  fold into the fixed member  14 , one above the other, and the third leg  28  folds into the left arm member  18 . To effect this fold, it is necessary to allow the legs to turn 45° from their platform supporting position. To this end, member  14  is provided with a shaped slot  29  at each end to receive lock bolt  58 . The slot  29  is continued a short distance away from the corner of the wall as shown in FIG. 4A. A similar slot arrangement is provided in a slide  38 . In this manner when the screw is loosened sufficiently, the leg can be pulled up through the associated hole and rotated 45°. Thereafter, it can be pivoted about its lock nut and bolt to a horizontal position in the channels  23  and  25 . By reversing the procedure, the leg can be returned to its table/platform supporting position. 
     FIGS. 4A through 14 illustrate the manufacturing details of the various members. Referring to FIGS. 4A and 5A, there is illustrated a blank  60  from which front member  14  is formed. Blank  60  includes a flat central member cut to provide tabs  61  and  62  at opposed ends which may be folded up to form the outer sides of member  14 . As shown in FIG. 5A, tabs  61 ,  62  are folded at an angle relative to horizontal support surface  15 . Advantageously, legs  30 ,  32  when raised into position against respective tabs  61 ,  62 , assume a posture wherein the leg ends touching the ground are disposed outwardly from the overall dimensions of the triangular base, thereby providing a added stability. Wall  20  is likewise folded upward to form an inside vertical wall supporting surface for the object to be carried. Prior to folding the tabs  61  and  62  and side  20 , the blank  60  is stamped to provide two rectangular oblique openings in the horizontal support surface  15  and slots  29  for receiving the associated locking bolt  58 . The dimension shown in FIG. 5A are in inches, as are all dimensions throughout the several drawings. 
     FIGS. 4A and 5B illustrate an alternate embodiment of the front member  14 . In this embodiment, horizontal support surface includes two tabs,  61  and  62 . Tabs  61  and  62  are crimped or notched as best shown in FIG. 4B at  63  and  64 , respectively to facilitate fabrication. Details of the punchouts  29  and C are illustrated in FIGS. 5-1,  5 - 2  and  5 - 3 . 
     FIGS. 6 and 7 illustrate the detail of right arm member  16  formed from flat blank  73  comprising support surface  17  and wall surface  21 . Support surface  17  includes an extension  74  beyond the wall surface  21  which has a central opening  46  adjacent the end which enables the arm member to be pivoted to member  14 . Wall surface  21  includes a central rectangular slot  41  with a further narrow slot  75  extending therefrom as shown in FIG.  3 . When assembled, as shown in FIG. 3, the slot  41  is partitioned off by a strut  66  having a lip  67  which engages the upper edge of member  16 . Strut  66  which is part of slide  38  thus confines arm  18  to the left most portion  40  of the slot as viewed in the drawing. 
     FIGS. 8 and 9 illustrate left arm member  18  formed from blank  76  to comprise a lower flat horizontal surface  19  and an upper wall surface  22 . Upper wall surface  22  excludes a finger like extension  68  curved inwardly after wall  22  is folded upwardly to provide a guide for the pivoting member. Flat surface  19  has an extension  70  which is pressed downward to be lower than surface  19  so that the extension  70  which pivots at  47  passes underneath the extension  48  of member  14  and thereby allows the lower surface  19  of member  18  to fold beneath member  14  in the collapsed position of the support. The opposite end of blank  19  includes an upper tab  71  which forms an upper end wall as shown in FIG. 8 which acts as a stop when member  18  is pivoted into its fold position with the edge  72  of the top abutting the outside wall surface of upper wall member  21 . 
     FIGS. 10 and 11 illustrate the details of the slide formed from a blank member  80 . Blank  80  includes a finger  81  adapted to be folded at  82  and  83  such that opening  84  is co-axially aligned with opening  85  to enable locking bolt  43  to be passed therethrough. Opening  85  may either be threaded or the locking bolt  43  is adapted to engage a nut beneath the base surface of blank  80 . Blank  80  includes several fold lines, shown as dash lines, to achieve the shape of the slide shown in FIG.  10 . Fold lines  86  and  87  serve to help form the strut  66  and channel  67  which engages the upper edge of member  16  for locking the two arms in position. Opening  86  (similar to slots  29  hereinbefore described) allows the leg locking mechanism for leg  28  to be appropriately positioned so as to permit the leg to be rotated downward in its folded position in the channel  25  formed by walls  21  and  22 . 
     FIG. 12 illustrates the construction of the supporting legs  28 ,  30 , and  32 , comprising each of which comprise sidewalls  88  and  89  and a central back connecting backwall  90  forming an access opening or slot  56  defining a central channel. Sidewalls  88  and  89  include lips  91  and  92  which restrict the opening  56  and enable nut  57  to be retained captively therein. The ends of the leg are closed off by end walls  93  and  94 . End wall  93  is slightly less than the height of the other channel in the leg in order to enable a screw to be inserted past the end wall and captively retained within the channel. 
     FIG. 13 illustrates the leg channel in cross section taken along the lines of  13 . While FIG. 14 illustrates the free members of the leg lock comprising bolt  58 , C-shape channel member  60  and lock nut  57 . Bolt  58  is passed through hole  59  in the channel member  60  to engage a lock nut captively held in a by channel. 
     While the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those of ordinary skill in the art that various changes and modifications may be without deviating from the inventive concept and spirit of the invention as set forth above, and it is intended by the appended claims to define all such concepts which come within the full scope and true spirit of the invention.