Abstract:
A tree stand includes a bowl 12 with a backpost 14 fastened therein. The backpost includes a set of jaws or teeth 40u which bear against the tree trunk. A set of upper and lower straps 60u and 60l is buckled to the backpost in a manner which allows the length to be changed. An overcenter clamp lever 64u, 64l is associated with the upper and lower straps, for tensioning the straps against the tree trunk. A set of standoffs 50 is interposed between the straps and the tree trunk at locations opposite to the jaws of the backpost. The tree stand bowl 12 has a spherical shape, which mates with a spherical bowl receptacle or base 32, allowing the bowl to be rotated or tilted relative to the bowl receptacle, to align the tree. A set of edge fasteners clamps the edges of the bowl to the bowl receptacle at the selected position.

Description:
FIELD OF THE INVENTION 
     This invention relates to stands for cut trees, such as Christmas trees. 
     BACKGROUND OF THE INVENTION 
     Cut-tree stands are widely used for supporting cut trees, especially Christmas trees. Such stands are subject to several requirements, which include the ability to hold a tree upright in a stable fashion, when the trunk of the tree may have been cut at an angle, and which may have various knots or cut branches adjacent the lower end of the trunk, which make the trunk irregular in the region in which support is required. Also, since the trunk may be curved, and the tree otherwise misshapen, it is desirable that the stand be capable of being adjusted in a manner which tilts the trunk, to allow the best appearance to be achieved. For this purpose, it is also desirable to be able to rotate the tree to put its best side toward the viewers. Further, in order to prolong the time during which the appearance of the tree is satisfactory, and to reduce the potential for fire, it is desirable that the stand hold water adjacent the cut end of the trunk of the tree. Further desiderata include the ability to collapse the stand into a small volume for storage, easy set-up, and the like. 
     U.S. Pat. No. 4,699,347, issued Oct. 13, 1987 in the name of Kuhnley, describes a stand including a base ring with three legs hinged thereto. The legs meet at an apex, at which a ball seat supports a ball, which can be rotated on the seat, and which may be clamped in a selected position. The ball is connected to a generally vertically disposed backplate or backpost, which is tiltable with respect to the vertical when the ball is not clamped, and which is held in position when the ball is clamped. The backpost or backplate is curved, as seen in a plane orthogonal to a vertical axis, and the concave side of the backplate is held against the tree trunk by a pair of straps without a tightening device, one near the top of the backplate, and the other near the bottom of the backplate. The straps are retained by buckles. The Kuhnley arrangement does not appear to have achieved widespread success, possibly because of the inability of the ball clamping mechanism to withstand the moments about the center of the ball which are generated by the weight of the tree. Any slippage of the ball when clamped would result in tilting of the tree, which might even overturn. Further, it appears that the backplate of Kuhnley is intended to be strapped to the tree trunk, and the straps can only be tightened, when the tree is lying on its side, and the tree is then raised to a vertical position, and the backplate is then engaged with the ball tilt arrangement. This may be expected to require substantial physical strength in the case of a large tree. Also, the Kuhnley arrangement makes no provision for watering the tree. 
     Another tree stand is described in U.S. Pat. No. 5,375,808, issued Dec. 24, 1994, in the name of Roy. The Roy arrangement includes three legs which support a backpost or jaw assembly. The backpost has a foot for supporting the bottom of the tree trunk, and upper and lower sets of teeth protruding radially inward, to bear against the trunk. A bar of somewhat flexible or yieldable material is hinged to the structure above the foot of the jaw. The cut end of the tree trunk is set against the foot, and a hinged bar is pressed against the tree trunk at a location above the base of the trunk, and curved about it, to press the trunk against the jaw. The bar is clamped in a position which presses the trunk firmly against the jaw. Tilt adjustment is accomplished by forcing the tree in the desired direction, which allows the trunk to pivot around the bar as a fulcrum, and allows the cut end of the tree to slip along the foot of the jaw. The Roy arrangement, while allowing the tree to be righted by simply pushing it in the desired direction, does not appear to have any way to prevent tilt from occurring inadvertently. Also, tilt can be accomplished only in planes approximately transverse to the length of the bar. 
     Improved cut-tree stands are desired. 
     SUMMARY OF THE INVENTION 
     A stand for a cut tree comprises an upward-facing bowl defining a bottom region about a center of the bowl. A support post, backpost or backplate is affixed to the bottom region of the bowl at a location spaced away from the center of the bowl, and projecting vertically upward from the bottom region. The backpost, in a plane orthogonal to an axis passing vertically through the center of the bowl, is generally concave as seen from the vertical axis. The backpost defines at least a lower tree-trunk engaging portion adjacent the bottom region of the bowl, and an upper tree-trunk engaging portion adjacent an upper portion of the backpost. Each of the lower and upper tree-trunk engaging portions includes a plurality of teeth, as seen in the orthogonal plane. The stand further includes a lower strap engaging the backpost, and dimensioned to extend about a tree-trunk, and to hold the tree-trunk against the teeth on the tree-facing side of the backplate. An upper strap engages the backpost at a location above the lower strap, and is likewise dimensioned to extend about the tree-trunk, and to hold the tree trunk against the teeth of the backplate. A lever including an over-center portion is affixed to the backpost and to at least one of the upper and lower straps. The lever is arranged, when operated, for tensioning at least one of the upper and lower straps, and for assuming a stable overcenter tensioned state which tends to hold the tree-trunk against the backpost. In a particular embodiment of the invention, the backpost includes a strap retaining coupler, which allows the effective length of a strap to be changed, and the upper and lower straps each have a backplate coupler at one end arranged to mate with one of the strap retaining couplers of the backplate. The strap retaining coupler of the backplate may be a simple buckle, or it may include a plurality of apertures, and the corresponding portion of the strap may be a simple hook dimensioned to mate with one of the apertures. In another embodiment, two backing support arrangements are traversed by or affixed to the straps, to bear against the tree trunk at spaced-apart locations, and to hold the straps away from the tree-trunk. The straps may pass through slots in the backing supports, so the backing supports can slide to the appropriate position before the straps are tightened. A small-tree adapter may be mated with the backplate, to present a smaller toothed circumference to a smaller tree. 
     According to another aspect of the invention, the bowl of the stand as so far described has a spherical outer surface, which is supported within a segment of another spherical bowl. The outer bowl segment is fixed in position, as by sitting on the floor, and the inner bowl can be rotated or tilted relative to the outer bowl, to thereby tilt or rotate the tree affixed to the backplate. A clamping arrangement clamps the upper edges of the two bowls together when the tilt is proper, to prevent further motion. The stand may be made from metal or a high-strength plastic material. 
    
    
     DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective or isometric view, exploded to illustrate the relationship of the elements, of a tree stand according to the invention, including a bowl, support post, upper and lower jaw units, straps, cam buckles, over-center clamp levers, and bowl receptacle; 
     FIG. 2 is another perspective or isometric view of a bowl and support post portion of the arrangement of FIG. 1, assembled and supporting a tree; 
     FIG. 3 is a side elevation view of the arrangement of the bowl and support post of FIG. 2; 
     FIG. 4 is a perspective or isometric view of the tree-facing side of the tree support post of FIGS. 1 and 2; 
     FIG. 5 is a top view of the support post and upper jaw unit of the arrangement of FIG. 1; 
     FIG. 6 is a perspective or isometric view of the rear of the support post of the arrangement of FIG. 1; 
     FIG. 7 is a perspective or isometric view, exploded to illustrate the various portions, of the over-center clamp lever of FIG. 1 and the associated portions of the support post; 
     FIG. 8 is a perspective or isometric view of a portion of the rear of the support post of another embodiment of the invention, illustrating, instead of a cam buckle, a plurality of coupling apertures adapted to mate with a hook or tab on a strap. 
    
    
     DESCRIPTION OF THE INVENTION 
     FIG. 1 is a simplified perspective or isometric view of a tree stand 10 according to the invention, exploded in order to illustrate the relationship of the elements. In FIG. 1, tree stand 10 includes a bowl 12 defining a bottom 12b and an upward-extending side 12s centered on an axis 8. Bottom 12b and side 12s together form a closed bowl capable of holding water. Bowl 12 has three outwardly-extending clamp lugs, one of which is designated 15a. A support post, backpost or backplate 14 is affixed within bowl 12. Backpost 14 is in the approximate shape of a portion of a circular cylinder, the axis of which is concentric with axis 8. Backpost 14 has a plurality of screw clearance apertures, one of which is designated 16a. Backpost 14 also has a plurality of outwardly-extending ears or lugs, one of which is designated 18a. A plurality of mutually parallel raised ridges 12br are defined in the bottom 12b of bowl 12, to engage the cut end of the tree trunk, and thereby minimize lateral displacement of the tree when mounted in the stand. 
     The side 12s of bowl 12 of FIG. 1 is in the shape of a portion of a sphere having a predetermined outer diameter. Bowl 12 fits within a bowl receptacle and support designated generally as 30. Bowl receptacle and support 30 includes a bowl receptacle 32 which is in the shape of a segment of a sphere having a diameter slightly larger than that of the bowl, to provide clearance, and to allow rotational and tilt movement of the bowl 12 within bowl receptacle and support 30. Bowl receptacle 32 has an open bottom or aperture 33, to allow spills of water to pass therethrough to the floor, where they can be readily wiped up. Bowl receptacle and support 30 also includes feet, one of which designated 34a, for providing a broad base for the tree stand. As illustrated in FIG. 1, bowl receptacle 32 has reinforcing members or ribs 36 extending across aperture 33. When bowl receptacle 32 receives bowl 12, the bowl may be rotated and tilted in the receptacle. When the appropriate position is found, screws 17 associated with the clamp lugs, such as screw 17a associated with clamp lug 15a, may be tightened. These screws 17 clamp the edge of the bowl receptacle between the clamp lugs and the sides 12s of bowl 12, to thereby prevent further movement. 
     Backpost or backplate 14 of FIG. 1 is the principal vertical support for the tree trunk. As mentioned above, backpost 14 is affixed within bowl 12, as by welding in the case of steel, or by forming as an integral or monolithic whole, in the case of plastic. A pair of upper and lower tooth or jaw units 40u and 40l have smooth, curved rear surfaces which mate with the curvature of the interior of backpost 14, and are affixed thereto by screws; for example, upper left screw 42ul, which passes through clearance aperture 16a, and which screws into a threaded aperture (not illustrated in FIG. 1) in the back of upper tooth unit 40u. A similar upper right screw 42ur passes through clearance hole 16b, and screws into the back of upper tooth unit 40u. Similarly, screws 42ll and 42lr extend through clearance apertures 16c and 16d, respectively, and into threaded apertures in the rear of lower tooth unit 40l. Instead of using screws to assemble the tooth units to the backplate, the tooth units and the backplate may be made as a unitary whole. As illustrated, the tooth or jaw units 40l and 40r have a plurality of teeth 44 on their front or tree-facing surfaces, for engaging with a tree trunk to aid in preventing unwanted movement of the tree trunk relative to backpost 14. 
     The trunk of the tree being supported (not illustrated in FIG. 1) is clamped against the teeth 44 of the tooth units 40u and 40l by a pair of upper and lower straps 60u and 60l. The straps may be woven nylon or the like, such as are commonly used for car carrier straps or luggage straps. In FIG. 1, upper strap 60u has a metal tip 60t to prevent unravelling, and passes through a cam buckle 62u, which, while illustrated in conjunction with the strap in FIG. 1, is actually affixed to the left edge of backpost 14, as illustrated in FIG. 2. Cam buckle 62u clamps strap 60u in any position along its length, to thereby adjust the strap length to accommodate the particular tree trunk being clamped. Strap 60u extends from cam buckle 62u, passes through an upper left standoff 50ul and an upper right standoff 50ur, and extends to the right to an over-center upper clamping lever 64u. Clamping lever 64u includes a plurality of hinge apertures 64ua, which, when the lever is assembled to lugs 18a of backpost 14, are registered with apertures therein. Lever 64u is held to lugs 18a by screws or rivets 65 extending through the apertures 64ua. This arrangement allows the hinge axis of the over-center lever 64 to be outside the region through which strap 60 passes, to provide the stability of over-center operation. Lower strap 60l similarly includes a metal tip, passes through a cam buckle, through standoffs 50ll and 50lr, and to an over-center lever 64l. Left standoffs 50ul and 50ll are held in a spaced-apart relationship by a spacing member 52l, and right standoffs 50ur and 50lr are similarly held by a spacing member 52r, to form upper and lower backing support arrangements. Spacing members 52l and 52r are coupled to the upper and lower standoffs at locations on the upper and lower standoffs which are remote from those portions of the upper and lower standoffs which engage the tree trunk, so that the spacing members are spaced away from the tree trunk during use, while the upper and lower standoffs engage the tree trunk. 
     FIG. 1 also illustrates a pair of small-tree adapters 80u and 80l, the backs of which are formed as teeth mating with the teeth 44 of jaw units 40l and 40r, so as to fit snugly against the jaw units. Upper small-tree adapter 80u has a projecting tab 82u, which is fitted with a downward-projecting pin 84u. When small-tree adapter 80u is fitted into the teeth 44 of jaw unit 40u, pin 84u mates with an aperture 40ua on jaw unit 40u, to hold the small-tree adapter in place. Lower small-tree adapter 80l similarly has a projecting tab 82l, which is fitted with a downward-projecting pin 84l. When small-tree adapter 80l is fitted into the teeth 44 of jaw unit 40l, pin 84lu mates with an aperture 40ul on jaw unit 40l, to hold small-tree adapter 80l in place. Small-tree adapters 80u and 80l have jaws and teeth on the tree-trunk engaging side, which are adapter for trees with smaller-diameter trunks than the teeth and jaws of jaw units 40u and 40l. 
     FIG. 2 illustrates the bowl 12, backpost 14, and some other elements of the tree stand according to the invention, with a tree trunk clamped between the teeth of the backpost and the standoffs. FIG. 3 illustrates the bowl and backpost of FIG. 2, with the tree in place. FIG. 4 illustrates, in perspective or isometric view, the interior or tree-facing side of backpost 14 and jaw units 40u and 40l. The teeth 44 are arranged to engage the tree trunk at upper and lower locations. 
     FIG. 5 is a simplified top view of the backpost 14, upper standoffs 50ul and 50ur, strap 60u, toothed jaw 40u, and over-center clamp lever 64u, to illustrate the clamping operation. The position of the strap 60u and lever 64u which is illustrated by solid lines is the clamped position. The loosened position of strap 60u and lever 64u is illustrated by phantom lines. It should be noted that the diameter of the loop, which the strap may make when lever 64u is in the loosened position, is determined by the amount of strap 60u which extends past buckle 62u. As also illustrated in FIG. 5, strap 60u passes through a slot (not separately designated in FIG. 5) in each of standoffs 50ul and 50ur, so that the standoffs are captive, but adjustable along the strap, and cannot be lost. Also, the standoffs remain in their relative positions despite loosening of the strap. 
     FIG. 6 is a perspective or isometric view of backpost 14, with the straps in their tensioned state, but omitting the tree trunk against which they are tensioned. In FIG. 6, the heads of screws 42ul, 42ur, 42ll, and 42lr are illustrated. As mentioned above, these screws may be used to hold the jaws 40u and 40l to backpost 14, or the screws may be dispensed with if the jaws and backpost are made as an integral or monolithic unit. Also illustrated in FIG. 6 is buckle 62u in its open state, with clamp lever 562u rotated about hinge pin 564u to its open position, to allow the clamping position on strap 60u to be adjusted. Lower buckle 62l has its clamp lever 562l rotated about hinge pin 564l to its closed state, in which strap 60l is clamped. Clamp levers 64u and 64l are illustrated in their clamped or tensioned state. 
     FIG. 7 illustrates details of clamp lever 64u. In FIG. 7, overcenter clamp lever 64u includes two protruding portions 714a and 714b, each of which defines a through aperture 64ua, dimensioned to clear screws 65. The spacing and alignment of apertures 64ua are such as to match with the spacing of threaded apertures 718a and 718b in lugs 18a and 18b, respectively. Apertures 718a and 718b are threaded to match screws 65. When assembled to lugs 18a and 18b, lever 64u hinges about screws 65. A strap retaining pin or rivet 710 passes through apertures 712 in lever 64u, and through a loop 760 formed in the end of strap 60u. This arrangement allows the strap to pass between lugs 18a and 18b, closer to the surface of backpost 14 than the hinge axis defined by screws 65, and to terminate at pin 710, which is also near the surface of backpost 14, which is an over-center condition which maintains the tensioned position of the lever without additional locks or catches. 
     Other embodiments of the invention will be apparent to those skilled in the art. For example, as suggested in FIG. 8, backpost 14 may, instead of buckles 62u and 62l, a series of rectangular apertures 862a, 862b, 862c . . . , which are dimensioned to accept a tab 814 formed at the end of a strap termination 810. An end of strap 60u is fastened to termination 810, as by rivets 812. The lower strap is arranged in a similar manner, with mating apertures, including aperture 762l, in the lower half of backpost 14. This arrangement may be cheaper than the buckles illustrated in FIGS. 1, 2, and 3, or may provide more positive retention.