The Model is relevant to a balancing device for table lamps and equivalent uses, with an equipment articulated respect to a horizontal axis, which can move angularly so that it results more or less slanting respect to the horizontal line. Since an equipment of this kind is not always in a state of neutral equilibrium for any position that it can take, it results advisable to provide a balancing system that can operate in a gradual way proportionally to the unbalance that said equipment generally undergoes when it gets away from the vertical line.

Substantially, according to the Model, between the base and support structure and the equipment articulated to said structure, a system arranged as an articulated quadrilateral and especially arranged as an articulated parallelogram is developed that becomes deformed in accordance to the angular displacement of the equipment, and a reaction elastic means is provided that operates along a diagonal of the system arranged as an articulated quadrilateral, in such a way that said means increases the elastic stress exerted on the equipment as it moves moving away its barycenter from the vertical line respect to the horizontal articulation axis; in this way the torque generated by the weight, which tends to increase with the further displacement of the lamp, is compensated.

In practice and advantageously the parallelogram or articulated quadrilateral is provided with at least one annular elastic member, that is deviated in a pulley transmission system in correspondence of three points on three articulations of the articulated parallelogram and that extends along the diagonal that tends to lengthen because the displacement of the articulated equipment, in the direction for which the barycenter of said equipment gets away from the vertical line respect to the articulation; the elastic ring is subject to tensile stress.

By providing a base and an equipment with a stem, two of the adjacent sides of the articulated parallelogram are realized respectively solid with the base and with the stem. In practice the system arranged as an articulated parallelogram is formed with two opposite sides each one defined by a small plate and the remaining two opposite sides each one defined by a couple of small plates. Three articulations of the system arranged as an articulated parallelogram carry projections with pulleys or equivalent at the opposite sides and on the pulleys two elastic annular elements are mounted and deviated, generally toric and especially rubber made or consisting of an helicoidal metallic spring.

The drawing shows a possible embodiment of the Model and in particular:

• Fig. 1 shows a perspective view of a portion of the lamp equipped with the balancing device considered in this description;
• Fig. 2 shows an exploded view of the components shown in Fig. 1;

The drawing shows a base provided with a plate 1 and a stanchion 3. At the end of the stanchion is articulated at 5, according to a horizontal axis, the equipment 7 of the movable portion of the lamp, and said equipment in particular includes a stem 9. The equipment is not balanced respect to the articulation axis and then the stress due to its weight tends to increase on it, as the equipment is lowered according to arrow f7, because the moving away of the barycenter respect to a vertical line indicated by V and passing in the area of the articulation 5. A balancing intervention is therefore advisable proper to tend to increase its own reaction for a lifting in the direction opposite to the arrow f7, as the equipment 7,9 is lowered. This is realized by the system arranged as an articulated quadrilateral and in particular arranged as an articulated parallelogram. To carry out this, there are provided according to the drawing: a small plate 10 solid with the stem 9; a couple of small plates solid with the stanchion 3 of the base, and articulated according to the articulation axis 5 to the small plate 10; a small plate 14 articulated at 16 to the couple of small plates 12 and located between them; a couple of small plates 18, articulated at 20 to the small plate 10 (that is located between them) and at 22 to the small plate 14 that is also placed between the plates 18). Thus an articulated parallelogram is generated, that, when the equipment 7,9 is lowered according to f7, becomes deformed with a progressive mutual moving away of the articulations 5 and 22.

Corresponding to the articulations 5,22 and 16, at the outside of the small plates constrained to said articulations small transmission wheels (or transmission buttons) are placed, indicated by R and on said wheels are mounted two elastic annular elements 24, that therefore extend triangularly and any way with a branch 24A substantially extending along the diagonal of the articulated parallelogram between the articulations 5 and 22. These branches 24A of the two elements 24 evidently lengthen and then the whole elements 24 lengthen, when the equipment 7,9 is lowered according to f7, thus increasing the reaction thrust on the articulated parallelogram that tends to impede the lowering of the equipment due to the effect of the weight.

Although the law, according that the elastic reaction of the balancing system varies, does not correspond exactly to what results necessary for a perfect balancing, the arrangement is sufficient to assure the balancing in combination with a suitable friction effect, that compensates the little differences in respect to a precise balancing.