Butterfly valve with an articulated control

Claim 2

A butterfly valve comprising a hollow valve body, a butterfly element located within said body, first link means pivotably mounted in said body at a first end of the link means and pivotably connected to said butTerfly element at a second end of the link means so as to suspend said butterfly element from the valve body, and a control device for controlling the position of the butterfly element, said device comprising a control spindle rotatably mounted in said body, a cranked lever pivoted to said valve body and having a first arm and a second arm which is pivoted to said butterfly element, and an articulated toggle structure having a first end connected to rotate with said control spindle and a second end pivoted to said first arm of said cranked lever.

Claim 3

A butterfly valve as claimed in claim 1, wherein said first arm of said cranked lever is longer than said second arm of said cranked lever.

Claim 4

A butterfly valve as claimed in claim 1, wherein said link means and said control device are placed on the same side of said butterfly element.

Claim 5

A butterfly valve as claimed in claim 1, wherein said link means and said control device are placed on opposite sides of said butterfly element.

Claim 6

A butterfly valve comprising a hollow body having a center axis, a butterfly element located in and coaxial with said body, a valve seat for said butterfly element, a first link means having a first end pivoted to said body and a second end pivoted to said butterfly element substantially in a transverse plane containing said axis so as to suspend said butterfly element inside said body, and a control device for controlling the position of said butterfly element with respect to said body, said device comprising a control spindle rotatably mounted in said body, a cranked lever pivoted to said body by a pivot pin and having a first arm and a second arm which is pivoted to said butterfly element substantially in said transverse plane, and a toggle structure comprising a first element having one end integral with said control spindle and a second end and a second element having a first end pivoted to said second end of said first element and a second end pivoted to said first arm of said cranked lever, said first and second elements of said toggle structure being so arranged with respect to said butterfly element and said valve seat that substantially maximum force is exerted by said toggle structure on said first arm upon rotation of said control spindle when said butterfly element is substantially in a position in which said butterfly element is applied against said valve seat.

Claim 7

A butterfly valve comprising a hollow body having a center axis, a butterfly element located in and coaxial with said body, a valve seat for said butterfly element, a first link means having a first end pivoted to said body and a second end pivoted to said butterfly element substantially in a transverse plane containing said axis so as to suspend said butterfly element inside said body, and a control device for controlling the position of said butterfly element with respect to said body, said device comprising a control spindle rotatably mounted in said body, a cranked lever pivoted to said body by a pivot pin and having a first arm and a second arm which is pivoted to said butterfly element substantially in said transverse plane, and a toggle structure comprising a first element having one end integral with said control spindle and a second end and a second element having a first end pivoted to said second end of said first element and a second end pivoted to said first arm of said cranked lever, said first and second elements of said toggle structure being so arranged with respect to said butterfly element and said valve seat that substantially maximum force is exerted by said toggle structure on said first arm upon rotation of said control spindle when said butterfly element is substantially in a position in which said butterfly element is applied against said valve seat.

Claim 8

A butterfly valve as claimed in claim 5, wherein said pivot pin pivoting said cranked lever to said body and said pivotal connection of said second arm to said butterfly element are contained in a plane substantially parallel to a plane containing said valve seat when said butterfly element is applied against said valve seat, and said link means is substantially parallel to said plane containing said valve seat, whereby, when opening said valve, said butterfly element first moves away from said valve seat in a direction substantially perpendicular to said plane of said valve seat.