Information
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Patent Grant
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6216997
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Patent Number
6,216,997
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Date Filed
Thursday, February 18, 199925 years ago
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Date Issued
Tuesday, April 17, 200123 years ago
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Inventors
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Original Assignees
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Examiners
- Braun; Leslie A.
- Landry; Walter
Agents
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CPC
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US Classifications
Field of Search
US
- 248 519
- 248 523
- 248 1887
- 248 183
- 248 1884
- 248 2161
- 047 405
- 047 42
- 047 43
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International Classifications
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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.
Claims
- 1. A tree stand comprises:a base and a clamping mechanism secured to said base, said clamping mechanism further comprising: a pair of opposed jaws, each having a pair of convergent clamping faces to clamp a tree at circumferentially and longitudinally spaced locations, and a drive mechanism for moving said jaws toward and away from one another to clamp and release said tree, the clamping faces on one of said opposed laws being offset longitudinally from adjacent clamping faces on the other of said opposed laws to permit said adjacent clamping faces to overlap upon movement of said opposed jaws toward one another.
- 2. A stand as claimed in claim 1 wherein each jaw comprises two pairs of clamping faces.
- 3. A tree stand according to claim 1, further comprising vertical adjusters located up on said leg assembly for adjusting an angle of said tree about said vertical axis.
- 4. A tree stand according to claim 2, wherein each of said opposed jaws includes two pairs of jaw elements, each of said jaw elements has one of said clamping faces associated therewith, a pair of said jaw elements on one of said opposed jaws being longitudinally spaced a distance less than a longitudinal spacing of an adjacent pair of jaw elements on the other of said opposed jaws, said opposed jaws being disposed relative to one another to permit said jaw elements on said one jaw to be accommodated within the jaw elements of said other jaw.
- 5. A tree stand according to claim 4, wherein said opposed jaws are constrained to slide relative to one another in direction approximately transverse to a longitudinal axis of said tree.
- 6. A tree stand according to claim 4, wherein said clamping faces are serrated.
- 7. A tree stand according to claim 5, wherein said drive mechanism includes a pair of threaded members for moving said pair of jaw elements towards one another.
- 8. A tree stand according to claim 7, wherein said pair of threaded members are located in holes contained in said pair of jaw elements, a diameter of said holes is larger than the diameter of said pair of threaded members for facilitating pivoting of said pair of jaw elements.
- 9. A tree stand according to claim 8, wherein said clamping mechanism permits pivoting of said jaw elements about both a horizontal axis and a vertical axis for providing clamping of said trunk at the circumferentially and longitudinally spaced locations.
- 10. A tree stand according to claim 7, wherein said pair of threaded members are located in a pair of corresponding recesses of said base.
- 11. A tree stand according to claim 1, wherein said base includes a leg assembly coupled to said base by a flange and complementary slot arrangement.
- 12. A tree stand according to claim 7, further comprising a float mechanism coupled to a water reservoir of said base for monitoring water levels therein.
US Referenced Citations (16)