Abstract:
A Christmas tree stand comprises a base and a clamping mechanism which has a pair of opposed jaws with generally v-shaped clamping faces and the jaws being disposed to clamp a tree at circumferentially and longitudinally spaced locations and means for moving the jaws towards and away from each other to clamp and release the tree.

Description:
FIELD OF THE INVENTION 
     This invention is concerned with tree stands and, in particular, with a stand for holding a Christmas tree. 
     BACKGROUND OF THE INVENTION 
     Tree stands currently on the market cover a wide range in costs, complexity and functionality. It is believed that all stands currently available fail in the fundamental requirement of reliably keeping the tree upright over a few weeks time. The fact that new variants enter the market and others disappear every year would seem to indicate that the marketplace, as a whole, shares this dissatisfaction. A good steady tree stand at a reasonable cost is somewhat of an elusive quest. 
     The failure of existing tree stands stems from the approach that designers have taken in their development. A common design on the Canadian market has, as its base, a small pot to serve as a water reservoir for the tree. Annular thumb screws near the top of the pot secure the tree in place. No additional secure thumb screws can be used near the bottom of the pot because, of course, the water would leak out. 
     To secure the tree at the bottom of the pot there may be an upward pointing spike or an oversized disk screwed to the base of the tree to prevent sideways motion. The leg arrangement may be three or four discrete legs extending out from the pot or a complete circular base of about sixteen inches in diameter. 
     These designs prove unreliable. It is not a problem of the stability of the base. Theoretically, a sixteen inch diameter base is adequate to prevent tipping. Furthermore, it can be shown that the base need not be heavily weighted to provide sufficient stability. Yet trees and stands of this design fall over just the same. The source of the problem can be traced to the clamping mechanism to securing the tree which is inadequate in firmly locking the tree to the base. 
     The clamping inadequacies arise from the thumb screw arrangement which is ill-suited to tree trunk shapes that may be quite uncircular and which behave plastically over time. The larger the tree, the less circumferential area the thumb screws cover proportionately, leading to loss of clamping effect. Spikes protruding from the bottom of the pot are often too short or too dull to dig into the trunk sufficiently to prevent sideway motion. The reservoir itself, which is a structural element of the stand, is often under designed, flexing and deforming upon the sideways loads imparted by the tree through the thumb screws. 
     Simply put, designers have approached the problem in reverse. Instead of starting with the essential design requirement of making the tree stand, they have started with the secondary requirement of providing a pot of water to the tree and then locate a clamping arrangement within the pot. 
     The present invention seeks to provide a strong clamping mechanism and a stable stand. 
     SUMMARY OF THE INVENTION 
     According to this invention, the tree stand comprises a base, a clamping mechanism comprising a pair of opposed jaws, each having inclined clamping faces to clamp a tree at circumferentially and longitudinally spaced locations and means for moving the jaws towards and away from each other to clamp and release the tree. 
     Preferably, each jaw comprises two pairs of clamping faces. 
     Preferably, the clamping faces of opposed pairs are longitudinally spaced apart. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows a perspective, partly exploded view of the stand according to this invention; 
     FIG. 2 is a perspective view of the clamping mechanism of the stand; 
     FIG. 3 is a vertical, central section of the stand; 
     FIG. 4 is a perspective view of the water container of the stand; and 
     FIGS. 5 and 6 are perspective views of one of the legs of the stand. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The stand comprises a base made up of four equiangularly spaced legs  10  which have bosses  12  into which nuts (not shown) are pressed at the lower or distal ends. Each nut receives a screw threaded adjustment bolt  14  which, as will become apparent, permit levelling of the assembly. 
     An injection molded water reservoir  16  is generally of square section having a peripheral flange  18  at its upper edge which, together with the adjacent portions of the outer surface of the reservoir, define a channel. Two slots  20  adjacent each of the four corners of the reservoir communicate with the channel. Integrally projecting shoulders  24  having stops  26  are molded on opposed interior walls of the reservoir to support the clamping mechanism in the manner described hereinafter. 
     An upright protrusion  28  is provided on the outer surface of the reservoir at each corner and it is slotted to receive a leg post as described hereinafter. 
     Each leg has a curved upper surface and a reinforcing rib  30  extending the length of the leg and projecting from the underside of the leg. The rib terminates in a leg post  32 . 
     A flange  34  is formed at the upper or proximal end of the leg and is shaped to conform to the corner portion of the reservoir. A pair of barbed latches  36  project from the upper edge of the flange and are located to register with the slots  20  of the reservoir. 
     Each leg is assembled to the reservoir by passing the flange  34  of the leg into the peripheral channel so that the latches snapped into the slot  20  and the leg post  32  enters into the slotted protrusions  28 . With all four legs assembled, the reservoir and legs constitute a very stable base. 
     The base is completed by a retaining cover  36  which has four depending latches  38 , one disposed centrally of each edge of the cover. The latches are engaged in matching slots  40  formed in the uppermost surface of the reservoir. A slot  42  is formed through the cover to receive a water level indicator  44  as seen in FIG.  3 . The indicator comprises a simple float with an index to show the maximum level of water. 
     Finally, for a purpose which will become apparent, a pair of recesses  45  are formed in the upper edge of one side of the reservoir. As will be described later, they provide access for parts of the clamping mechanism. 
     The clamping mechanism is illustrated in FIG.  2 . It comprises of a pair of substantially similar steel jaws, one being a fixed jaw  50  and the other, a movable jaw  52 . Each jaw has an upper pair of wedge-shaped jaw elements  56  and  58  defining clamping faces or edges  60  and  62 . As indicated in chain line on jaw  62  of the movable jaw  52 , the faces or edges are preferably made with a serrated form for increased gripping penetration of the tree. It will be apparent that other forms can be used. 
     Each jaw has a lower pair of wedge-shaped jaw elements  64  and  66  defining clamping faces or edges  68  and  70 . It is to be noted that the vertical spacing between jaw elements  56  and  66  is greater than that between jaw elements  58  and  64 . 
     A pair of ears  76  and  78  are pressed from the jaws and, as can be seen from FIG. 3, these support the clamping mechanism on the shoulders molded in the interior of the reservoir. 
     The clamping force is provided by a pair of bolts  72  and  74 . The bolts are passed freely through holes in the fixed jaw  50  so the bolt heads bear on the back surface of that jaw. Two pairs of barbs  80  are pressed from the movable jaw and within each, there is a nut  82  with which the bolts are engaged. The barbs  80  serve to prevent rotation of the nuts but are provided with a loose fit to permit the jaws to move with some “slop” to accommodate irregularities in the trees to be clamped. Turning knobs  84  are fixed to the bolts. Assuming the use of right-hand threads, it will be apparent that counterclockwise rotation (as viewed in FIG. 2) will close the moving jaw to advance towards the fixed jaw to exert a clamping force on a tree located between them and clockwise movement will move the jaws apart. The clamping structure is placed in the reservoir with the ears  76  and  78  supporting it on shoulders  24  of the reservoir. The bolts  72  and  74  are accommodated in the recesses  45  of the reservoir. 
     It will be recognized the base structure is very stable and can be easily demounted for storage by flexing the latches to remove the legs. It is also to be appreciated that a tree will be gripped at eight locations which are circumferentially and vertically spaced so that it is very firmly clamped. The clamping is achieved using only two bolts as opposed to prior art arrangements using multiple thumb screws. It is to be appreciated that the stand will accommodate trees of a wide range of diameters and of significantly irregular shapes. 
     It is to be recognized that the clamping force is not transmitted to the base but is extended and borne by the clamping mechanism itself. This permits the use of a base which need not sustain those forces. This is in contrast to the prior art arrangements discussed above where the base/reservoir is an integral part of the clamping mechanism.