Deformable wheel useful for instance as a vehicle wheel or in a gearing

A wheel capable of functioning without internal pressure, comprising:

• a central part;
• a radially deformable peripheral tread whose peripheral length is substantially constant surrounding said central part and radially spaced therefrom;
• and
• means for connecting said central part to said tread, said means having a first radial dimension when the unpressurized wheel is not loaded and has no internal pressure and a second radial dimension when the wheel is under the load it is intended to support and has no internal pressure and lies on flat ground, said second radial dimension being greater than said first radial dimension by no more than one tenth of said first radial dimension, and said means being substantially unable to generate an outwardly directed resilient force on a part of the tread in response to an inwardly directed displacement of said part of the tread rim from the position it has when said wheel is under said load it is intended to support, said connecting means including at least one ply containing cords which are rigidly connected to and extend between said central part and said tread and which are essentially untensioned and have a first length when said connecting means have said first radial dimension and which are tensioned and have a second length when said connecting means have a second radial dimension, the difference between said first and second lengths resulting in inwardly directed radial forces exerted by said connecting means on said tread, said ply having in a radial plane a curve whose axial radius r is greater than a limit relative to H, H being the radial distance between the central part and the tread when the wheel is unloaded and unpressurized, said limit being equal to 0.75 H under the condition when the ratio H/R equals 0.35 R, R being the radius of the wheel in the same condition, said limit being higher if said ratio is smaller.