Supports – Stand – Plural leg
Reexamination Certificate
2000-01-20
2001-07-03
King, Anita M. (Department: 3632)
Supports
Stand
Plural leg
C248S188500, C248S170000
Reexamination Certificate
active
06254043
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a stand comprising at least three legs, the upper part of which is fastened to the stand head in a hinged or tiltable manner and the lower part of which is telescopically displaceable in the upper part, locking means being provided for mutually locking the legs in the transport position of the stand.
2. Description of the Related Art
A conventional tripod stand, for example a stand of the GST 120-9 series of the Applicant, has locking means mounted on the legs for locking the latter to one another for transport and for securing them to prevent them from falling apart. The locking means comprise, on each leg, a hook mounted on the boot and a strap which is mounted on a clamp fitting through which the lower, displaceable part can be clamped in the upper stationary part of the leg. For locking, the clamp fittings are released and the hooks of each leg are inserted in succession over the strap of the adjacent leg. Thereafter, the legs are retracted and the clamp fittings are tightened, with the result that hook and strap engage one another and prevent the legs from falling apart. The locking means are identical on all three legs.
That all three clamp fittings have to be sufficiently firmly clamped is disadvantageous. The clamping screws of the clamp fittings are tightened or released when the legs are hooked one into the other. Moreover, owing to vibrations during transport, these screws might become loosened and might even become undone. Owing to the limited space in the transport position, the clamping screws may not exceed a maximum size, with the result that the tightening force to be applied is limited. The operation of the clamping screws is difficult particularly during surveying work on the ground in cold weather. In addition, an operator has to bend to reach the respective clamping screws of the clamp fittings.
If one of the clamp fittings disengages, there is the danger that a leg will be released; if a further clamp fitting becomes disengaged, all three legs would unfold.
BRIEF SUMMARY OF THE INVENTION
It is the object of the invention to provide a stand whose legs can be locked simply and in a user-friendly manner with high safety.
This object is achieved by a stand in which the features of the independent Claim are realized.
Advantageous or alternative embodiments are described by the features of the dependent Claims.
In contrast to the point-symmetrical arrangement of the locking means in conventional stands, the locking means of the invention lack point symmetry. After releasing the clamp fittings, the other legs of the stand are hooked in on a first, central leg of the stand. The legs are then retracted, it being necessary finally only to clamp the central leg in the retracted state. Consequently, all three legs are simultaneously secured to prevent falling apart and extensions.
The locking means comprise a first support plate on the central leg and further support plates on each of the other legs. In the embodiment of the invention, the support plate of the central leg may have projections, for example pegs, which are oriented upwards towards the head of the stand. The further support plates of the auxiliary legs have associated recesses, for example holes, which are placed on the pegs of the first support plate of the central leg. Alternatively, however, the pegs can also comprise straps which are coordinated with the auxiliary legs. In alternative embodiments of the invention, pegs pointing downwards away from the head of the stand can be arranged on the further support plates of the auxiliary legs, which pegs are inserted into associated holes in the support plate of the central leg. In an alternative embodiment, the further support plates of the auxiliary legs may also have pegs pointing upwards towards the head of the stand. For locking, the auxiliary legs are swivelled inwards in order to place their support plates on the first support plate of the central leg. A strap fastened to the upper stationary section of the central leg, preferably to the clamp fitting, passes around the pegs when the stand legs are retracted.
In the context of the invention, “support plate” is to be understood as meaning inward-pointing attachments of any shape which engage one another when the stand is in the transport position.
The support plates are each fastened to the so-called boots of the stand legs or in the region thereof, which are mounted at the lower end of the displaceable part of the legs in order to place the stand legs on the ground. According to the invention, the support plates of the auxiliary legs are generally placed on the first support plate of the central leg, but it is also possible to provide measures which permit supportive retention of the further support plate by means of an appropriately formed spindle which is optionally coordinated with the clamp fitting of the central leg, extends through all support plates and fixes them in the vertical position. In the retracted state, pegs and holes or strap engage one another so that one or both auxiliary legs cannot slip out or fold open. Even if an auxiliary leg is released, the other auxiliary leg remains firmly locked.
The clamp fitting arranged at the lower end of the upper part of the central leg can be used for keeping the stand legs in the retracted position. Separate clamping of the auxiliary legs is not required. Advantageously, locking is used in combination or alternatively to this and begins at the upper ends of the two parts of the central leg, which ends point towards the stand head. For additional securing, the clamp fitting may also be clamped. Expediently, this locking takes place at discrete points. This may comprise, for example, a clamping spring with a recess which a peg engages. The clamping spring may be fastened to the upper end of the upper part of the central leg, and the peg to the upper end of the displaceable part of the central leg. In the retracted position, the clamping spring moves over the peg until the latter snaps into the recess. The two components of the locking means may also be conversely arranged by fastening the peg to the upper end of the upper part and the clamping spring to the upper end of the lower displaceable part of the central leg. Alternatively, instead of the clamping spring, it is also possible to provide a snap spring which—particularly when arranged on the inside of the central leg—engages a relatively large recess in the upper and of the lower part of the central leg. Advantageously, stops which damp the retraction movement and/or the extension movement of the lower parts of the legs and are optionally coordinated with the recess are provided. For locking the legs in the retracted state, it is no longer necessary for the operator to bend.
Such locking on all three legs in combination with the devices known per se for preventing the legs from swivelling out constitutes a particularly simple possibility for equipping existing stands. Thus, it would in principle not be necessary to provide support plates.
Expediently, a spacer is coordinated with the first support plate of the central leg so that, when the further support plates of the auxiliary legs are placed on the support plate of the central leg, the auxiliary legs are kept the required distance from the central leg. Mutual engagement of the pegs in the holes or the locking straps can therefore be performed rapidly and exactly. The spacer may be a bracket or a plastics member which is fastened to the first support plate of the central leg or optionally coordinated with the auxiliary legs.
REFERENCES:
patent: 205481 (1878-07-01), Gurley
patent: 1234510 (1917-07-01), Trautwein
patent: 3963207 (1976-06-01), Guasti
patent: 4767090 (1988-08-01), Hartman et al.
patent: 5072910 (1991-12-01), May
patent: 5222705 (1993-06-01), Gibran et al.
patent: 5320316 (1994-06-01), Baker
patent: 412715 (1924-07-01), None
patent: 2257355 (1993-01-01), None
patent: 09170925 (1997-06-01), None
King Anita M.
Leica Geosystems AG
Rothwell Figg Ernst & Manbeck
Sy Holly N.
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