Patent US4498308A successfully refreshed from Google Patents.
US3633367A
Expired / Lapsed
US
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Master cylinder assembly for vehicle hydraulic brake systems
Assignee: Fiat SpA
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Filing: 1970-05-27
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Granted: 1972-01-11
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Expires: 1990-05-27
Abstract
Abstract A master cylinder assembly for vehicular hydraulic brake systems has a cylinder closed at one end, with a piston sliding in the cylinder and defining therein a compression chamber which communicates through first and second ports with a point of use and an hydraulic fluid reservoir respectively. A reaction spring urges the piston away from the closed end of the cylinder against a stop and flow of hydraulic fluid through the said second port is controlled by valve means. According to this invention the valve means comprise a tubular member, slidable, with axial and radial play, in the compression chamber, a frontal annular packing carried by the tubular member and cooperating with an annular radial seat, and a peripheral annular packing adapted to seal against the said lateral wall of the cylinder bore. The two said ports are always disposed on opposite sides of the peripheral packing and the tubular member is biased towards a position in which the frontal packing is spaced from its seat, permitting open communication between the two ports when the piston is resting against its stop. Means are provided for displacing the tubular member towards the said seat upon the movement of the piston towards the closed end of the cylinder for actuating the brakes.
Inventors
- 👤 Philip S Baldwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:31
CPC Classifications
B; B60; B60T; B60T11/00; B60T11/10; B60T11/16; B60T11/20; B60T11/165
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
278 words
Master cylinder assembly, particularly but not exclusively for hydraulic brake systems for vehicles, comprising: i. a cylinder having one end open and the other end closed; ii. a piston slidingly mounted in the cylinder and defining with a portion of the bore of the cylinder and with the closed end of the latter a compression chamber; iii. first and second ports communicating with the compression chamber and adapted to be connected to a point of use and to an hydraulic fluid reservoir respectively; iv. a stop; v. a reaction spring urging the piston away from the closed end of the cylinder against the stop; vi. valve means controlling the flow of hydraulic fluid through the said second port, and further comprising the improvement which consists in vii. the said valve means comprising a tubular member slidingly mounted, with axial and radial play, in the said portion of the bore of the cylinder which constitutes the compression chamber; viii. an annular seat disposed in a radial plane of the cylinder; ix. a frontal annular packing adapted to cooperate with the said annular seat; x. a peripheral annular packing adapted to seal against the wall of the said portion of the cylinder bore, the said ports being always disposed on opposite sides of the said peripheral packing; xi. means biassing the said tubular member towards a position in which the frontal packing is spaced from the respective seat, leaving open communication between the two ports when the piston is resting against the said stop, and xii. means adapted to displace the tubular member towards the said seat upon the movement of the piston towards the closed end of the cylinder.
Claim 2
Dependent Claim
278 words
Master cylinder assembly, particularly but not exclusively for hydraulic brake systems for vehicles, comprising: i. a cylinder having one end open and the other end closed; ii. a piston slidingly mounted in the cylinder and defining with a portion of the bore of the cylinder and with the closed end of the latter a compression chamber; iii. first and second ports communicating with the compression chamber and adapted to be connected to a point of use and to an hydraulic fluid reservoir respectively; iv. a stop; v. a reaction spring urging the piston away from the closed end of the cylinder against the stop; vi. valve means controlling the flow of hydraulic fluid through the said second port, and further comprising the improvement which consists in vii. the said valve means comprising a tubular member slidingly mounted, with axial and radial play, in the said portion of the bore of the cylinder which constitutes the compression chamber; viii. an annular seat disposed in a radial plane of the cylinder; ix. a frontal annular packing adapted to cooperate with the said annular seat; x. a peripheral annular packing adapted to seal against the wall of the said portion of the cylinder bore, the said ports being always disposed on opposite sides of the said peripheral packing; xi. means biassing the said tubular member towards a position in which the frontal packing is spaced from the respective seat, leaving open communication between the two ports when the piston is resting against the said stop, and xii. means adapted to displace the tubular member towards the said seat upon the movement of the piston towards the closed end of the cylinder.
Claim 3
Dependent Claim
109 words
Master cylinder assembly as claimed in claim 1, wherein the said tubular member has a diameter differing from that of the piston, the said biassing means for the tubular member comprising radial flanges formed on the tubular member and the piston respectively, the flange on the piston being disposed between the flange on the tubular member and the closed end of the cylinder, and the distance of the flange on the piston from the closed end of the cylinder when the piston is resting against the said stop being greater than the distance which separates the flange on the tubular member from the sealing surface of the frontal packing.
Claim 4
Dependent Claim
181 words
Master cylinder assembly as claimed in claim 2, wherein the bore of the cylinder has a first section of smaller diameter at the open end of the cylinder, a second section of greater diameter situated at the closed end of the cylinder, an annular shoulder separating the second section from the first section, the said annular shoulder facing the said closed end and forming the said stop for the piston, and wherein the said piston has a part extending into the second said section and formed with the said radial flange, the external diameter of said flange being greater than the diameter of the said first bore section, and the said tubular member being slidingly mounted in the said second bore section and having an inner diameter greater than the external diameter of the said radial piston flange, and wherein the radial flange of the tubular member extends inwardly to an internal diameter which is less than the external diameter of the piston flange, said flange on the tubular member being interposed between the said piston flange and the annular shoulder.
Claim 5
Dependent Claim
37 words
Master cylinder assembly as claimed in claim 3, wherein the said means adapted to displace the tubular member towards the said seat comprise a helical spring interposed between the said tubular member and the said annular shoulder.
Claim 6
Dependent Claim
58 words
Master cylinder assembly as claimed in claim 4, including a washer against which the end of the said helical spring which is remote from the annular shoulder bears, the said washer resting against the peripheral annular packing, and the said peripheral packing in turn resting against a radial shoulder formed in the external surface of the tubular member.
Claim 7
Dependent Claim
71 words
Master cylinder assembly as claimed in claim 5, wherein the said rAdial shoulder against which the peripheral annular packing rests is formed in a region of the tubular member of greater wall thickness than the end of the tubular member which faces the closed end of the cylinder, and including a seat for the frontal annular packing in the form of a terminal enlargement of the bore of the tubular member.
Claim 8
Dependent Claim
36 words
Master cylinder assembly as claimed in claim 1, wherein the radial seat cooperating with the frontal annular packing is formed upon the end of a threaded plug which closes the said other end of the cylinder.
Claim 9
Dependent Claim
46 words
Master cylinder assembly as claimed in claim 7, wherein the said plug is hollow, having a blind bore opening into the interior of the tubular member, the said blind bore having an internal diameter which is substantially equal to the internal diameter of the tubular member.
Claim 10
Dependent Claim
40 words
Master cylinder assembly as claimed in claim 8, wherein the bottom of the blind bore of the plug forms an abutment surface for one end of the reaction spring which urges the piston towards the open end of the cylinder.
Claim 11
Dependent Claim
54 words
Master cylinder assembly as claimed in claim 9, wherein the piston is formed in its end facing towards the closed end of the cylinder with a blind bore, and wherein the end of the reaction spring remote from the hollow plug rests against the bottom of the said blind bore formed in the piston.
Claim 12
Dependent Claim
46 words
Master cylinder assembly as claimed in claim 1, including at least one radial vent in the wall of the tubular member, the interior of the said tubular member communicating with the said port adapted to communicate with a point of use by way of said vent.
Claim 13
Dependent Claim
135 words
Master cylinder assembly as claimed in claim 1, wherein the piston has means defining, in correspondence with its part which is close to the open end of the bore of the cylinder, two peripheral grooves of rectangular cross section, a first sealing ring located with both axial and radial play, in one said groove, and a second sealing ring located with axial play in the other said groove; the first sealing ring having a substantially rectangular cross section with an outwardly curved profile on its surface facing the bore wall of the cylinder, and the second sealing ring having an H-shaped cross section with the end surfaces parallel to each other and perpendicular to the axis of the piston, and being disposed nearer the open end of the cylinder bore than the first sealing ring.
Claim 14
Dependent Claim
63 words
Master cylinder assembly as claimed in claim 1, including at least one sealing ring effecting sealing between the outer surface of the piston and the cylinder bore section in which the piston slides, the said sealing ring being of the annular cap type and being located in respective peripheral grooves of rectangular cross section formed in the external peripheral surface of the piston.
Claim 15
Dependent Claim
99 words
Master cylinder assembly as claimed in claim 1, said assembly being adapted for use in a hydraulic brake system having two separate hydraulic pressure utilizing circuits, the cylinder of the assembly housing first and second pistons in tandem, a first reaction spring acting on the first piston, a hollow plug closing the bore of the cylinder and supporting the first spring, the said first piston having at its opposite end an abutment, and a second reaction spring bearing against said abutment and acting upon the second piston, the second piston having means for engagement by a mechanical brake-operating member.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |