BACKGROUND OF THE INVENTION It is known, that the modern workplace is often a complex equipped with various combinations of displays, automatic printers, graph plotters, personal COMPUTERS and etc. The administrative and special furniture, as workplace equipment, should differ from home appliances by number of parameters. The ergonomic models of armchairs and chairs developed now contribute to reduction of number of mistakes made by the personal, raise attention concentration, keep vigorous state of health and good mood within all working day, in comparison with usual ones.

However, the known models are designed for a user's normal bearing and consequently appear to be hardly effective for those which bearing is deformed as a result of work on armchairs and chairs intended for a conditions of life. Therefore the developers of special furniture offer such technical decisions which are directed on reduction of a nervous-muscular overstrain, exhaustions psychosensorial mechanisms of a human organism and reduction of probability of the appearance of occupational diseases.

The special operator's chair is known which contains a basis on which the sacral support with the working surface with an inclination is located, knee unit [see the statement to the patent of the USSR N° 1823787, published of 20. 09.90, ICI A 47 C 1/02] and supports for foot stop. The sacral support is moveable relatively to the telescopic rack. During working activity of the user the position of the centre of gravity of a body changes because of inclinations of the trunk to the various sides and hand moves of the user.

Also, the working armchair is known which contains a seat mounted on the basis which are connected with a collapsible sliding rack [see the statement to the patent of the USSR Ns 1734679 published of 17. 09.90, ICI. A 47 C 1/02] and has a shin rest and a support for foot stop.

It is supposed, that the user of the technical decisions described above will feet comfortable in any position.

However, if the user has the wrong bearing such design may result in aggravation of damage. Besides, the designs described above are difficult in manufacturing and cumbersome as they occupy additional space in comparison with habitual chairs and armchairs.

Besides, it is known a chair-support, containing the basis, the seat established on the basis by means of the rack, having hinge connection with the basis with an opportunity of its installation at various angle of an inclination to the basis [see the statement of Avt. Svid. of the USSR Ns 1253612 published of 11. 10.84, ICI. A 47 C 1/027], and the handle of seat position management, and as well as rack fixer at various angles of an inclination to the basis, including the holed plate placed in the basis with apertures and the rod placed in the rack with an possibility of reciprocating moving along the axis, one end is connected to the control handle, and another interacting with the plate apertures when the rack inclination angle to the basis changes.

In authors'opinion, fixing of a chair-support at various angles to the basis allows to lower static loadings on muscles of legs and loin, improving working conditions due to optimization of a working pose.

As well as in the previous case, the technical decision described above fixes habitual position of the user, thus aggravating the defective bearing.

The most similar to the declared decision according to its purpose, technical essence and the application result that must be reached while using is the chair-support is containing the basis, the seat established on the basis with the rack, connected with hinge to the basis with an possibility of its installation at various angle of an inclination to the basis [see the statement to Avt. Svid. of the USSR N2 1407481 published of 14. 11. 86, ICI. A 47 C 1/027], and the seat position control handle, and as well as the rack fixer at various inclination angle of the basis, including the holed plate placed in the basis and the rod placed in the rack with an possibility of reciprocating moving along the axis, one end is connected to the control handle, and another interacting with apertures when the rack inclination angle to the basis changes, and also an additional plate and two holders allows to provide not only the fixed position of the rack and a seat, but also a floating operation mode.

The maintenance of a floating operation mode expands functionalities of a chair-support as special furniture.

However, the presence in the design of the several springs constantly stretching, both in the basis of the rack and in the basis of a seat, and the presence of the mechanism switching modes, complicates the device essentially and reduces its reliability, reducing term of its operation.

SUMMARY OF Tl IE INVENTION Therefore the purpose of the offered technical decision is simplification of a design, increase of its reliability and service life.

The basis of the invention is the improvement of the chair-support in which, in consequence of performance of the hinge providing inclination of the rack, as the springing- loaded rod, on which the bottom end of the rack rests, thus the spring and the bottom end of the rack are located in the case, with external and internal conic surfaces placed in the basis of a chair-support, and execution of the spring-loaded rod with an element of a spherical surface, the possibility of inclination of the rack in any direction not tensile stress, but compression stresses in the design elements, is provided, and due to the simplification of the design and increase of its reliability is achieved.

The set task is solved so that in the known chair-support, containing the basis, the seat established on the basis by means of the rack, connected with a hinge to the basis with a possibility of its installation at various inclination angles to the basis, according to the invention, the hinge providing inclination of the rack, is executed as a springing rod, on which the bottom end of the rack rests, thus the spring and the bottom end of the rack are placed in the case with external and internal conic surfaces and placed in the basis of a chair-support, and the spring- loaded rod is executed with an element of a spherical surface.

The hinge, providing an inclination of the rack, may be executed so, that the element of a spherical surface of one rod end is located inside its case and interacts with the end of the rack.

The hinge, providing inclination of the rack, may be executed so, that the element of the spherical surface of other rod end is located outside of its case.

As it is seen from a statement of technical essence of the declared decision, it differs from the prototype and, hence, is new.

The solution has also the inventive level. It is known the basis of a chair [see the statement to the patent of the USSR ? 021 16742 published 21.12. 93, ICI A 47 B 91/00] in which its one internal wall is executed conic to prevent a lateral inclination and slipping of the rack downwards on the cartridge. The offered technical solution essentially differs from known one not only excluding the certain rack slipping to the cartridge, but also allows a floating mode of the rack position concerning of the rack vertical axis.

Besides, as the study of the scientific and technical information has shown (patent and not patent, see for example, the Forestry, wood, paper and woodworking industry. The republican <BR> interdepartmental scientific and technical collection. -Kiev: Budivelnik, 1990, issue 21, page 86- 88 ; the MIR PK, October, 1999) all technical solutions in this Field are directed on fixing a presumably convenient position for the user, but they do not promote formation, correction and strengthening of correct bearing.

The offered device not only allows to take a convenient position, but also induces to movements, directed to correction of bearing, trains a muscular corset, improves heart, brain, spinal and pelvic blood circulation.

The offered technical decision, being simple and reliable, stimulates a reflex of the spine alignment, which arises on the suggested device as compensatory reflex reaction on the support fluctuations and possible fall down. The appearing effect of alignment is similar to the reflexes arising at riding which define correct bearing of people regularly engaged in riding.

The offered technical decision is widely applied at creation of complexes of modern school and office furniture.

USE OF THE INVENTION Examples of realization of the declared technical solution and its work are shown on figs.

I-3.

Figs. I, 1 a The assembled chair-support.

Figs. 2, 2a, 2b The hinge providing inclination of the rack, assembled and in working positions (the Example)).

Figs. 3, 3a, 3b The hinge providing inclination of the rack, assembled and in working positions (the Example 2).

Example 1. A chair-support (figs. 1, la, 2a, 2b) contains the basis 1, the seat 2, established on the basis by means of the rack 3, connected with hinge to the basis with a possibility of its installation at various angles to the basis (Figs la). The rack 3 is executed with a possibility of its height control (not shown on figures). The hinge 4, providing inclination of the rack 3, is executed as a spring-loaded rod 5, on which the bottom end of the rack 3 rests, thus tha spring 6 and the bottom end of the rack 3 are located in the case 7, having external 8 and internal 9 conic surfaces, and placed in the basis of I of chair-support. The end of the rack 3 also is executed with a conic surface 10. The spring-loaded rod 5 has an element of a spherical surface I 1. Together with a spring 6 the rod 5 is fixed in the case 7 relatively to the end of the rack 3 with the help of a back nut 12. It is possible to carry out not only a floating mode of the device operation, but also to the fixed mode by simple regulation of a spring compression with the back nut 12.

The hinge 4, providing an inclination of the rack 3, is executed so, that the element of a spherical surface I I interacts with the end of the rack 3. The cavity, providing a point contact of the spherical surface element 1 I with the rack end 3, is executed at the end of the rack for this purpose.

Example 2. As in the first case, the chair-support (Figs. 1, 3, 3a, 3b), contains the basis 1, the seat 2, established on the basis by means of the rack 3, connected with the hinge to the basis) with a possibility of its installation at various angles to the basis I (Figs. Ia). Thus the hinge 4, providing an inclination of the rack 3, is executed so, that the element of the spherical surface 13 is located outside the case 7 and rests, for example, on the floor 14 of the room.

The device works as follows. As it is shown in figs. 2a, 2b, and also 3a, 3b, the backlash 15 appears at loading the rod 3 due to compression of a spring 6 between the end of a rod 3 and the case 7. There is a possibility to incline the rack 3 and seat 2, as shown in figs. 2b and 3b, to any side convenient for the user, because the bottom end of the rack 3 has a point contact with a spherical element of a surface 10 of rod 5, or the spherical element of surface 13 has a point contact with the floor 14, at presence of a backlash 15 between the internal conic surface 9 of case 7 and conic surface 10 of the end of the rack 3.

As it is seen from statement of examples descriptions, the offered solution has a simple design, is capable to provide both a floating and fixed mode. It is reliable in operation and capable to provide long term of work, carrying out both its main function-a piece of furniture to sit on, and additional one-means for correcting of user's bearing.