US3717392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Relating to hydrostatic bearings
Assignee: William Asquith Ltd
•
Filing: 1971-02-16
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Granted: 1973-02-20
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Expires: 1991-02-16
Abstract
Abstract The invention provides a hydrostatic bearing arrangement for a machine tool. Two ''''floating pad'''' type hydrostatic bearings are active between first and second relatively movable parts of the machine, the bearings facing in opposite directions. A detector is fixed relatively to the first relatively movable part, and directs a fluid outlet towards a reference surface. The back pressure at the detector is measured and and the pressure of fluid supplied to one of the bearings is controlled in proportion to that at the detector, the pressure at the other bearing being reduced as that at the first bearing increases and vice versa. A special resilient detector is also described.
Inventors
- 👤 B Ennis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:36
CPC Classifications
F; F16; F16C; F16C32/00; F16C32/06; B; B23; B23Q; B23Q1/00; B23Q1/25; B23Q1/26; B23Q1/38; B23Q1/385; F16C29/00; F16C29/02; F16C29/025; F16C2322/00; F16C2322/39
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
210 words
A bearing arrangement active between first and second relatively movable parts of a machine and comprising at least two floating pad type hydrostatic bearings located on the first part and acting in opposite directions on the second part, means whereby each of said floating pad bearings is urged by fluid pressure differential into contact with said second part, at least one detector fixed relatively to the first part and directing a fluid outlet towards a reference surface fixed relatively to a desired path of movement of the moving part, means for supplying fluid under pressure simultaneously to the detector and the two hydrostatic bearings, valve means to regulate the pressure of fluid applied to the first hydrostatic bearing in response to detected back pressure in the detector and generally in proportion to that back pressure, and adding valve means adapted to feed fluid to the second hydrostatic bearing at a pressure equal to a constant pressure less than the pressure of the fluid supply to the first hydrostatic bearing whereby the sum of the pressure applied to the first and second bearings remains constant, said adding valve means having outlet means in addition to that supplying pressure to said second hydrostatic bearing permitting fluid flow through said adding valve means.
Claim 2
Dependent Claim
210 words
A bearing arrangement active between first and second relatively movable parts of a machine and comprising at least two floating pad type hydrostatic bearings located on the first part and acting in opposite directions on the second part, means whereby each of said floating pad bearings is urged by fluid pressure differential into contact with said second part, at least one detector fixed relatively to the first part and directing a fluid outlet towards a reference surface fixed relatively to a desired path of movement of the moving part, means for supplying fluid under pressure simultaneously to the detector and the two hydrostatic bearings, valve means to regulate the pressure of fluid applied to the first hydrostatic bearing in response to detected back pressure in the detector and generally in proportion to that back pressure, and adding valve means adapted to feed fluid to the second hydrostatic bearing at a pressure equal to a constant pressure less than the pressure of the fluid supply to the first hydrostatic bearing whereby the sum of the pressure applied to the first and second bearings remains constant, said adding valve means having outlet means in addition to that supplying pressure to said second hydrostatic bearing permitting fluid flow through said adding valve means.
Claim 3
Dependent Claim
210 words
A bearing arrangement active between first and second relatively movable parts of a machine and comprising at least two floating pad type hydrostatic bearings located on the first part and acting in opposite directions on the second part, means whereby each of said floating pad bearings is urged by fluid pressure differential into contact with said second part, at least one detector fixed relatively to the first part and directing a fluid outlet towards a reference surface fixed relatively to a desired path of movement of the moving part, means for supplying fluid under pressure simultaneously to the detector and the two hydrostatic bearings, valve means to regulate the pressure of fluid applied to the first hydrostatic bearing in response to detected back pressure in the detector and generally in proportion to that back pressure, and adding valve means adapted to feed fluid to the second hydrostatic bearing at a pressure equal to a constant pressure less than the pressure of the fluid supply to the first hydrostatic bearing whereby the sum of the pressure applied to the first and second bearings remains constant, said adding valve means having outlet means in addition to that supplying pressure to said second hydrostatic bearing permitting fluid flow through said adding valve means.
Claim 4
Dependent Claim
210 words
A bearing arrangement active between first and second relatively movable parts of a machine and comprising at least two floating pad type hydrostatic bearings located on the first part and acting in opposite directions on the second part, means whereby each of said floating pad bearings is urged by fluid pressure differential into contact with said second part, at least one detector fixed relatively to the first part and directing a fluid outlet towards a reference surface fixed relatively to a desired path of movement of the moving part, means for supplying fluid under pressure simultaneously to the detector and the two hydrostatic bearings, valve means to regulate the pressure of fluid applied to the first hydrostatic bearing in response to detected back pressure in the detector and generally in proportion to that back pressure, and adding valve means adapted to feed fluid to the second hydrostatic bearing at a pressure equal to a constant pressure less than the pressure of the fluid supply to the first hydrostatic bearing whereby the sum of the pressure applied to the first and second bearings remains constant, said adding valve means having outlet means in addition to that supplying pressure to said second hydrostatic bearing permitting fluid flow through said adding valve means.
Claim 5
Dependent Claim
35 words
A bearing arrangement as claimed in claim 1, in which a restrictor is provided in said additional outlet means, and fluid flow through the restrictor is proportional to the pressure at said second hydrostatic bearing.
Claim 6
Dependent Claim
39 words
A bearing arrangement as claimed in claim 1, in which the first valve means comprises a restrictor valve adapted to supply fluid to the first hydrostatic bearing at a pressure proportional to the detected bAck pressure at the detector.
Claim 7
Dependent Claim
32 words
A bearing arrangement as claimed in claim 1 in which the detector has a part which is able to yield when contacted by the reference surface to prevent damage to the detector.
Claim 8
Dependent Claim
72 words
A bearing arrangement as claimed in claim 4, in which the detector comprises a piston slideable within a housing in a direction towards and away from the reference surface, the piston being bored to provide the fluid outlet, but being arranged in its housing so that the fluid supplied to the detector urges the piston towards the reference surface, there being a step to limit movement of the piston in this direction.
Claim 9
Dependent Claim
47 words
A bearing arrangement as claimed in claim 5, in which the piston is spring urged towards the second relatively movable part to ensure that the clearance between the piston and the second relatively movable part is at a minimum when fluid is first applied to the bearings.
Claim 10
Dependent Claim
42 words
A bearing arrangement as claimed in claim 6, in which said yieldable sleeve is a sleeve surrounding the piston and spring urged in the same direction as the piston to act as a scavenging device for fluid flowing out of the detector.
Claim 11
Dependent Claim
44 words
A bearing arrangement as claimed in claim 1, in which the detector is arranged to direct its fluid flow on to a surface of the second relatively movable part, that surface being parallel with the desired path of movement of the first moving part.
Claim 12
Dependent Claim
36 words
A bearing arrangement as claimed in claim 1, in which the detector is arranged to direct its fluid flow on to a reference member (such as a straight edge) mounted independently of the relatively movable parts.
Claim 13
Dependent Claim
21 words
A bearing arrangement as claimed in claim 1 in which the detector is adjustable towards and away from the reference surface.
Claim 14
Dependent Claim
70 words
A machine tool having a bearing arrangement as recited in claim 1 in which one of said parts is mounted for longitudinal movement (e.g., the ram of a horizontal boring machine) and is supported by at least three floating pad type hydrostatic bearings each with adjustable detectors and so arranged that the supported part can be tilted in the planes at right angles to each other about its longitudinal axis.
References Cited (Backward Citations)
US3062593A
Cited
US3251633A
Cited
US3260162A
Cited
GB1076404A
Cited
FR1372163A
Cited
GB1013299A
Cited
US3266854A
Cited
US3398996A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |