Servo boosters

Claim 2

A tandem fluid-pressure servo booster coMprising a housing, a rigid internal wall within the housing, a movable wall on each side of said rigid internal wall, said walls defining four chambers axially spaced within the housing, a plurality of fluid passageways defined between an internal surface of said housing and the periphery of said rigid internal wall connecting a first pair of said chambers, and a plurality of tubular ducts, within said housing, connecting a second pair of said chambers, said tubular ducts each having an end region located in said rigid internal wall and passing through peripheral regions of one of the said movable walls.

Claim 3

A tandem fluid-pressure servo booster as claimed in claim 1 and wherein said movable wall through which the tubular ducts pass, comprises a flexible diaphragm.

Claim 4

A tandem fluid-pressure servo booster as claimed in claim 2 and wherein said flexible diaphragm includes an enlarged peripheral region.

Claim 5

A tandem fluid-pressure servo booster as claimed in claim 3 and wherein said enlarged peripheral regions of said flexible diaphragms are axially retained between an internal shoulder defined by the housing and said rigid internal wall.

Claim 6

A tandem fluid-pressure servo booster as claimed in claim 3 and wherein the tubular ducts pass through the enlarged peripheral regions of the diaphragm.

Claim 7

A tandem fluid-pressure servo booster as claimed in claim 1 and wherein said rigid internal wall includes inclined surfaces which seat against inclined surfaces in the peripheral region of the movable wall through which said tubular ducts pass.

Claim 8

A tandem fluid-pressure servo booster comprising a housing, a rigid internal wall within the housing, a movable wall on each side of the rigid wall, said walls defining four chambers axially spaced within the housing, a plurality of fluid passageways between an internal surface of the housing and the periphery of the rigid wall connecting a first pair of said chambers, and a plurality of tubular ducts, within the casing, connecting a second pair of said chambers, said tubular ducts each having one end located in the rigid internal wall and passing through the peripheral regions of one of the movable walls and wherein the rigid internal wall has a flange extending axially away from the tubular ducts.

Claim 9

A tandem fluid-pressure servo booster comprising a housing, a rigid internal wall within the housing, a movable wall on each side of the rigid wall, said walls defining four chambers axially spaced within the housing, a plurality of fluid passageways between an internal surface of the housing and the periphery of the rigid wall connecting a first pair of said chambers, and a plurality of tubular ducts, within the casing, connecting a second pair of said chambers, said tubular ducts each having one end located in the rigid internal wall and passing through the peripheral regions of one of the movable walls and wherein the rigid internal wall has a flange extending axially away from the tubular ducts.

Claim 10

A tandem fluid-pressure servo booster as claimed in claim 7 and wherein the tubular ducts lie substantially parallel to the axis of the booster and the rigid internal wall includes radial and axial passages opening to the tubular ducts and to the chamber adjacent the rigid wall and remote from said ducts.

Claim 11

A tandem fluid-pressure servo booster as claimed in claim 7 and wherein the movable wall through which the tubular ducts pass includes an inwardly directed lip in sealing engagement with the rigid internal wall.

Claim 12

A tandem fluid-pressure servo booster as claimed in claim 7 and wherein the tubular ducts are arranged in groups and said groups are spaced circumferentially about the peripheral regions of the rigid internal wall.

Claim 13

A tandem fluid-pressure servo booster as claimed in claim 7 and wherein the tubular ducts each have one end located in the rigid internal wall and said flange is in sealing engagement with the peripheral regions of the movable wall remote from the tubular ducts.

Claim 14

A tandem fluid pressure servo booster according to claim 7 wherein said flange engages and seals a peripheral region of one of the movable walls against an annular ring seated within the housing.

Claim 15

A tandem fluid-pressure servo booster as claimed in claim 12 and wherein said flange has its outer end region reduced in diameter to enter into an axially extending peripheral flange on the movable wall remote from said tubular ducts.

Claim 16

A tandem fluid-pressure servo booster as claimed in claim 12 in which the movable wall remote from the tubular ducts has an enlarged peripheral region which is axially retained between the flange of the internal wall and an annular ring seated within the housing, said annular ring defining a cylindrIcal wall and a radial flange, the peripheral regions of the movable wall being seated within the cylindrical wall and the radial flange being seated against radial shoulders within the housing.

Claim 17

A tandem fluid-pressure servo booster as claimed in claim 12 and wherein an axially extending peripheral flange on the movable wall is held in position on the reduced end of the flange of the rigid internal wall by an annular retaining band.

Claim 18

A tandem fluid-pressure servo booster as claimed in claim 15 and wherein said axially extending peripheral flange on the movable wall includes at least one annular projection upstanding from the outer surface of said flange and the annular retaining band engages said annular projection to inhibit removal of the peripheral flange from the flange of the rigid internal wall.

Claim 19

A tandem fluid-pressure servo booster as claimed in claim 12 in which the peripheral flange of the movable wall includes axially extending tongues which are received in respective recesses in the flange of the rigid internal wall and said tongues have a thickness, in the radial direction, greater than the thickness of the remaining parts of said peripheral flange.

Claim 20

A tandem fluid-pressure servo booster comprising a housing, a rigid internal wall within the housing, a movable wall on each side of said right internal wall, said walls defining four chambers axially spaced within the housing, an axially extending flange on said rigid wall the housing includes ribs defining fluid passageways radially outwardly of a flange of the rigid internal wall and passing radially over a union between said flange and a movable wall engaged thereon, said fluid passageways connecting a first pair of said chambers, and a plurality of tubular ducts, within said housing, connecting a second pair of said chambers, said tubular ducts each having an end region located in said rigid internal wall and passing through the peripheral regions of one of the movable walls.

Claim 21

A tandem fluid-pressure servo booster comprising a housing, a rigid internal wall within the housing, a movable wall on each side of said right internal wall, said walls defining four chambers axially spaced within the housing, an axially extending flange on said rigid wall the housing includes ribs defining fluid passageways radially outwardly of a flange of the rigid internal wall and passing radially over a union between said flange and a movable wall engaged thereon, said fluid passageways connecting a first pair of said chambers, and a plurality of tubular ducts, within said housing, connecting a second pair of said chambers, said tubular ducts each having an end region located in said rigid internal wall and passing through the peripheral regions of one of the movable walls.

Claim 22

A tandem fluid-pressure servo booster as claimed in claim 18 and wherein the face of the rigid internal wall remote from the flange includes radial slots connecting the said fluid passageways with that chamber between said slotted side of said rigid internal wall and the movable wall adjacent thereto.

Claim 23

A tandem fluid-pressure servo booster as claimed in claim 18 in which the fluid passageways are connected to the chamber between the side of the rigid internal wall remote from the flange and the movable wall adjacent thereto by holes passing substantially radially through the peripheral regions of the said rigid internal wall.

Claim 24

A tandem fluid-pressure servo booster as claimed in claim 18 in which the housing comprises two metal shells connected together at cooperating peripheral regions and peripheral regions of said two movable walls and said internal rigid wall are clamped axially between radial shoulders of the two shells.

Claim 25

A tandem fluid-pressure servo booster comprising a housing, a rigid internal wall within the housing and a movable wall on each side of said rigid internal wall, said walls defining four chambers axially spaced within the housing, a plurality of fluid passageways defined between an internal surface of said housing and the periphery of said rigid wall connecting a first pair of said chambers and a plurality of axially extending fluid ducts connecting a second pair of said chambers, an axially extending rod connecting both movable walls and constituting a common output rod, said axially extending ducts being radially spaced from the axis of said output rod, a first one of said movable walls being axially located on the common output rod by a sleeve member and said movable wall presenting an axially extending resilient lip sealingly engaged with the sleeve.

Claim 26

A tandem fluid-pressure servo booster comprising a housing, a rigid internal wall within the housing and a movable wall on each side of said rigid internal wall, said walls defining four chambers axially spaced within the housing, a plurality of fluid passageways defined between an internal surface of said housing and the periphery of said rigid wall connecting a first pair of said chambers and a plurality of axially extending fluid ducts connecting a second pair of said chambers, an axially extending rod connecting both movable walls and constituting a common output rod, said axially extending ducts being radially spaced from the axis of said output rod, a first one of said movable walls being axially located on the common output rod by a sleeve member and said movable wall presenting an axially extending resilient lip sealingly engaged with the sleeve.

Claim 27

A tandem fluid-pressure servo booster as claimed in claim 22 and wherein the sleeve passes through the rigid internal wall and a flexible seal is provided between the internal wall and the sleeve.