Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
238 words
1/ Hydraulic assistance device comprising a body - (10) comprising a bore (12) in which a first piston means and a second piston means (18, 20) are slideably mounted the first piston means (18) being movable under the effect of the actuation of a third piston (16) slideably mounted in the body (10), and the second piston means (20) being movable by the intermediary of a hydrostatic connection formed in a pressure chamber (22) defined between the first and the second piston means (18, 20) a respective valve means (60, 100) being associated with each piston means (18, 20) in a respective hydraulic circuit between a source of fluid under pressure (52, 96) and a respective braking circuit - (74, 110) ; and a third chamber (36) defined in the bore (12) between the first piston means (18) and the third piston (16), the said third chamber (36) being connected to a low pressure reservoir (25) through a passage in which a valve means (42) is mounted characterised in that the device comprises a second valve means (112) in a second passage (130, 132) between the third chamber - (36) and the reservoir (25), the second valve means (112) being responsive to the pressure of the corresponding source of pressure (52) so that upon failure of this high pressure source, the second valve means (112) closes so as to isolate the third chamber (36) from the reservoir (25).
Claim 2
Dependent Claim
238 words
1/ Hydraulic assistance device comprising a body - (10) comprising a bore (12) in which a first piston means and a second piston means (18, 20) are slideably mounted the first piston means (18) being movable under the effect of the actuation of a third piston (16) slideably mounted in the body (10), and the second piston means (20) being movable by the intermediary of a hydrostatic connection formed in a pressure chamber (22) defined between the first and the second piston means (18, 20) a respective valve means (60, 100) being associated with each piston means (18, 20) in a respective hydraulic circuit between a source of fluid under pressure (52, 96) and a respective braking circuit - (74, 110) ; and a third chamber (36) defined in the bore (12) between the first piston means (18) and the third piston (16), the said third chamber (36) being connected to a low pressure reservoir (25) through a passage in which a valve means (42) is mounted characterised in that the device comprises a second valve means (112) in a second passage (130, 132) between the third chamber - (36) and the reservoir (25), the second valve means (112) being responsive to the pressure of the corresponding source of pressure (52) so that upon failure of this high pressure source, the second valve means (112) closes so as to isolate the third chamber (36) from the reservoir (25).
Claim 3
Dependent Claim
50 words
2/ Device as claimed in Claim 1, characterised in that the second valve means (112) comprises a stepped bore (114) having a first end (124) connected to the source of pressure, a second end (128) connected to the third chamber (36) and an intermediate zone connected to the reservoir (25).
Claim 4
Dependent Claim
54 words
3/ Device as claimed in Claim 2, characterised in that the stepped bore comprising an annular wall - (136) the valve means (112) comprising a seal - (120) which is capable of cooperating with the annular wall (136) so as to close the passage between the third chamber (36) and the reservoir - (25).
Claim 5
Dependent Claim
43 words
4/ Device as claimed in Claim 3, characterised in that the valve means (112) comprises a piston means which is housed in the first end (124) of the stepped bore (114) and which is responsive to the pressure of the high pressure source.
Claim 6
Dependent Claim
35 words
5/ Device as claimed in any of the preceding claims, characterised in that the second piston means (20) has a surface facing the pressure chamber (22) which corresponds to the cross-section of the bore (12).
Claim 7
Dependent Claim
58 words
61 Device as claimed in claim 1 characterised in that the first piston means (18) comprises a control piston (226) on which is fixedly mounted a ball - (228) adapted to close a valve seat (202) in the first piston means, to thereby close the fluid passage between the first pressure chamber (22) and the third chamber (36).
Claim 8
Dependent Claim
29 words
7/ Device as claimed in Claim 6 characterised in that the second piston means (20) is linked to the respective valve means (210) by a telescopic arrangement (78, 206).
Claim 9
Dependent Claim
52 words
8/ Device as claimed in Claim 6 or 7 characterised in that it further comprises a tilting valve (236) in a second passage between the third chamber (36) and the low pressure reservoir (25) and moveable into an open position by the first piston means when this is in its rest position.