fig1 a and 1b show an assembly in accordance with one embodiment of the invention formed of a platform assembly 100 and a cylindrical structure or tower 200 , respectively with the platform assembly on the ground and with the platform assembly raised . fig2 shows in more detail one embodiment of the assembly shown in fig1 a and 1b . the tower 200 comprises a vertical structure with at least three posts 250 two of which can be seen in fig1 a and 1b . the tower may also comprise walls between the vertical posts or braces connecting the vertical posts to stiffen the structure , for example braces 260 forming crossmembers or crossed helices , as shown in fig2 . the posts and the braces are metal tubes or structural sections , for example . in accordance with the present invention , the platform assembly 100 intended to receive passengers is mobile within the tower 200 . for example , it is driven up the tower by cables 220 of a drive system . in the example of fig1 a , 1 b and 2 , the tower is substantially cylindrical with a circular base and the circular platform assembly is provided with arms or beams enabling it to be spaced from the tower . this shape is not limiting on the invention , however , and the cylindrical structure forming the tower can have any section , for example hexagonal , triangular or square . as shown in fig2 , the platform assembly 100 may comprise seats 150 for passengers . for example , the seats are arranged around a central platform 110 of the platform assembly , itself connected to the drive system by beams or arms 120 . the seats may face toward the inside or the outside of the tower . in the former case , the passengers have the benefit or a more friendly arrangement ; in the latter case , they have a direct view over the panorama . the seats may also pivot on themselves so that the passengers have the benefit of a 360 ° view . the platform assembly may also comprise a cover or roof 400 enabling protection of the passengers from inclement weather . the platform assembly being connected directly to the drive system rather than suspended , stability is significantly improved and a large number of passengers may be arranged around the central platform , even in an irregular manner . for example , the passengers are arranged within a circle that must have a diameter sufficient to accommodate all the passengers comfortably . the tower may have a height between 30 m and 80 m in order to afford a good panoramic view when passengers are raised up on the platform assembly . moreover , the platform assembly being connected directly to the drive system , it is possible for the passengers to have a completely unrestricted view in the raised position of the platform assembly ( fig1 b ), including of the structure itself . for example , the posts 250 comprise guide rails in which the drive cables 220 are placed , for example cables of the type used for lifts . the guide rails are adapted to accommodate respective carriages 300 fastened to the ends of the beams 120 of the platform assembly . each cable may extend from a winch 160 at the base of the tower to an idler pulley 210 at the top of the tower with a return run from the pulley 210 to the winch 160 . the winch may be of the type used for lift installations ; it may be associated with a control unit for controlling the direction of rotation of the cable 220 and regulate its speed ; the control unit also synchronizes the movement of the three carriages so that the platform assembly rises in the tower level , i . e . keeping the central platform 110 horizontal . fig3 shows a detail view of the platform assembly driving system in one embodiment . fig3 shows a portion of a post 250 of the tower and a portion of a beam 120 connected to the central platform of the platform assembly . fig3 also shows a carriage 300 accommodated in guide rails of the post 250 and attached to a drive cable 220 . the cable 220 has two cable runs on either side of the idler pulley 210 ( fig1 a , 1 b ), a first cable run to which the carriage is attached defining a driving path and a second cable run defining a return path toward the winch 160 for winding in the cable . each winch may be associated with a motor for driving movement of the cable in one direction or the other . for example , there may be three motors synchronized by an electronic unit to control the movement of the three cables to drive three carriages of the balloon along three posts of the tower . there may of course be more than three carriages and more than three motors if the tower has more than three vertical posts . there may equally well be a single motor driving movement of three cables . fig3 also shows a view in lateral section of a carriage 300 of substantially parallelepiped shape appropriate to a c - section ( 240 ) inside which it slides . the c - section is attached to a post 250 of the cylindrical supporting structure . the carriage is pulled by the cable 220 . lateral rollers 350 , of which there are four , for example , bear on the right - hand and left - hand sides of the c - section . transverse rollers 360 bear on the back of the c - section or on these returns . the arms or beams 120 of the platform assembly rest on the shoe of the carriage via a flexible damping member 370 of the silentbloc ® type that provides a flexible interface . a sling 320 suspends the arm from the carriage . its length is adjustable to adjust the distribution of forces between the sling ( tension ) and the silentbloc ® ( compression ) and to optimize the behaviour of the platform assembly . greater tension in the slings will be reflected in a greater freedom of movement of the platform assembly . greater compression of the silentbloc ® will be reflected in more severe recentring of the platform assembly . in order to increase the safety of the passengers , the use of a plurality of synchronized motors to drive the movement of a plurality of cables driving the carriages provides redundancy in the event of a breakdown or of a cable breaking . if a cable breaks , the carriage attached to that cable will slide along the post under its own weight , which will cause the platform assembly to tilt toward the post with the broken cable . this tilting , even if not dangerous to safety , may nevertheless frighten the passengers . a fall - preventing mechanism may therefore be provided on each carriage 300 . in normal operation , the cable 220 takes the weight of the carriage and the platform assembly . the tension in the cable 220 drives vertical movement in translation of the link 380 . the spring 381 is stretched and the finger 310 is retracted inside the carriage . if the cable 220 breaks , the tension in the cable disappears and the link is free to move in downward translation , being pulled by the spring 381 and causing the finger 310 to swing toward the exterior of the carriage . the carriage then falls freely until the projecting finger 310 strikes against a tooth of the rack 230 fixed to the back at the centre of the c - section . the spring 382 enables damping of the impact when the link strikes the rack and therefore stopping of the carriage and the platform assembly . fig4 shows one embodiment of a platform assembly comprising a central platform 110 connected to the cylindrical structure by beams 120 . for example , the central platform is equipped with seats 150 for the passengers arranged around a structure forming a bar . the bar and the passengers are protected by a cover 400 . the cover may be of any kind and may include an advertising sign , for example . it could be inflatable , for example . this inflatable cover could advantageously have an ellipsoidal shape , as shown in fig4 , in order to offer minimum wind resistance when the platform assembly is in the raised position and the cover extends beyond the upper edge of the tower . although described by way of a certain number of detailed embodiments , the assembly formed of the mobile platform assembly and the cylindrical structure in which the platform assembly is designed to be raised lends itself to different variants , modifications and improvements that will be obvious to the person skilled in the art , it being understood that these different variants , modifications and improvements fall within the scope of the invention as defined by the following claims .
the invention concerns an assembly comprising a platform assembly intended to receive passengers and a cylindrical structure , the platform assembly being mobile within the cylindrical structure . the assembly has very high stability as well as offering the passengers strong sensations of being raised up in the open air , with minimum obstruction of a panoramic view .