Pneumatic vehicle suspension with failsafe internal stop

Claim 2

A vehicle suspension comprising a pneumatic spring having a closed body with first and second rigid members interconnected by a toroidal shape flexible member of substantially gas-impermeable material and provided within the pneumatic spring an elastomeric spring having a first end connected to said first rigid member and a second end which is spaced from said second rigid member when the closed body of the pneumatic spring is pressurized to a normal working pressure, said second end being free to move transversely relative to said first end, the elastomeric spring being positioned within the closed body of the pneumatic spring such that in normal use of the vehicle suspension applied compression loading is withstood solely by the pneumatic spring and such that the applied compression loading acts on the elastomeric spring only in the event of a pressurization failure of the pneumatic spring, said elastomeric spring being of generally circular cross-sectional shape in a plane perpendicular to the normal direction of movement of the rigid members one towards the other and of pregressively increasing external diameter over at least a part of the length thereof from one end of the elastomeric spring to the other whereby in the event of pressurization failure of the pneumatic spring the elastomeric spring allows relative movement of the first and second rigid members both in said normal direction of movement of the rigid members one towards the other and in directions perpendicular thereto and whereby both the vertical compression stiffness and horizontal shear stiffness of the elastomeric spring progressively increase when, in use, the elastomeric spring is subject to an increasing compression loading.

Claim 3

A vehicle suspension according to claim 1 wherein the external diameter of the elastomeric spring within the pneumatic spring follows a convex path as considered in a plane containing said normal direction of movement of the rigid members one towards the other.

Claim 4

A vehicle suspension according to claim 1 wherein the external diameter of the elastomeric spring within the pneumatic spring increases progressively over the whole of the length of the elastomeric spring.

Claim 5

A vehicle suspension according to claim 1 wherein the external diameter of the elastomeric spring within the pneumatic spring increased progressively over part of the length of the elastomeric spring and decreased progressively over a remaining part of the length of the elastomeric spring.

Claim 6

A vehicle suspension according to claim 4 wherein the external surface of the part of progressively decreasing diameter is of a convex shape as considered in a plane containing said normal direction of movement of the rigid members one towards the other.

Claim 7

A vehicle suspension according to claim 1 wherein the elastomeric spring within the pneumatic spring is of a hollow construction over part of the length thereof.

Claim 8

A vehicle suspension according to claim 6 wherein the elastomeric spring is positioned with said hollow part remote from said first end of the elastomeric spring.

Claim 9

A vehicle suspension according to claim 1 wherein the elastomeric spring provided within the pneumatic spring has a rigid facing member for contact with the second rigid member in the event of at least partial de-pressurization of the pneumatic spring.

Claim 10

A vehicle suspension according to claim 1 wherein said elastomeric spring within the pneumatic spring and said second rigid member of the pneumatic spring are formed with interengageable location means arranged to interengage in the event of at least partial deflation of the pneumatic spring thereby to restrain relative movement between said elastomeric spring and rigid member in a direction transverse to said normal direction of movement of the rigid members one towards the other.

Claim 11

A vehicle suspension according to claim 9 wherein one of said location means is a rod of tapered shape.

Claim 12

A vehicle suspension according to claim 1 wherein said pneumatic spring is arranged in series with a second elastomeric spring external of the pneumatic spring and one end of which is connected to one of said rigid members and the other end of which is for connection to one of a vehicle body and a vehicle wheel assembly.

Claim 13

A vehicle suspension according to claim 11 wherein said second elastomeric spring has an external profile substantially similar to that of the elastomeric spring located within the pneumatic spring.

Claim 14

The vehicle suspension of claim 1 in which the elastomeric spring is of hollow construction over part of its length and of solid construction over the remaining part of its length.

Claim 15

The vehicle suspension of claim 13 in which the solid part is adjacent the end connected to said first rigid member.

Claim 16

A vehicle suspension comprising a pneumatic spring having a closed body with first and second rigid members interconnected by a toroidal shape flexible member of substantially gas-impermeable material and provided within the pneumatic spring an elastomeric spring having a first end connected to said first rigid member and a second end which is spaced from said second rigid member when the closed body of the pneumatic spring is pressurized to a normal working pressure, said second end being free to move transversely relative to said first end, the elastomeric spring being positioned within the closed body of the pneumatic spring such that in normal use of the vehicle suspension applied compression loading is withstood solely by the pneumatic spring and such that the applied compression loading acts on the elastomeric spring only in the event of a pressurization failure of the pneumatic spring, said elastomeric spring being of generally circular cross-sectional shape in a plane perpendicular to the normal direction of movement of the rigid members one towards the other, the elastomeric spring being substantially hollow over part of the length thereof remote from said first end which is connected to the first rigid member, the external diameter of the elastomeric spring within the pneumatic spring increasing progressively over part of the length of the elastomeric spring and decreasing progressively over a remaining part of the length of the elastomeric spring from said first to said second end of the spring whereby in the event of pressurization failure of the pneumatic spring the elastomeric spring allows relative movement of the first and second rigid members both in said normal direction of movement of the rigid members one towards the other and in directions perpendicular thereto and whereby both the vertical compression stiffness and horizontal shear stiffness of the elastomeric spring progressively increase when, in use, the elastomeric spring is subject to an increasing compression loading.

Claim 17

A vehicle suspension comprising a pneumatic spring having a closed body with first and second rigid members interconnected by a toroidal shape flexible member of substantially gas-impermeable material and provided within the pneumatic spring an elastomeric spring having a first end connected to said first rigid member and a second end which is spaced from said second rigid member when the closed body of the pneumatic spring is pressurized to a normal working pressure, said second end being free to move transversely relative to said first end, the elastomeric spring being positioned within the closed body of the pneumatic spring such that in normal use of the vehicle suspension applied compression loading is withstood solely by the pneumatic spring and such that the applied compression loading acts on the elastomeric spring only in the event of a pressurization failure of the pneumatic spring, said elastomeric spring being of generally circular cross-sectional shape in a plane perpendicular to the normal direction of movement of the rigid members one towards the other, the elastomeric spring being substantially hollow over part of the length thereof remote from said first end which is connected to the first rigid member, the external diameter of the elastomeric spring within the pneumatic spring increasing progressively over part of the length of the elastomeric spring and decreasing progressively over a remaining part of the length of the elastomeric spring from said first to said second end of the spring whereby in the event of pressurization failure of the pneumatic spring the elastomeric spring allows relative movement of the first and second rigid members both in said normal direction of movement of the rigid members one towards the other and in directions perpendicular thereto and whereby both the vertical compression stiffness and horizontal shear stiffness of the elastomeric spring progressively increase when, in use, the elastomeric spring is subject to an increasing compression loading.