US3714819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Applanation tonometer comprising porous air bearing support for applanating piston
Assignee: Bio Rad Laboratories Inc
•
Filing: 1970-11-19
•
Granted: 1973-02-06
•
Expires: 1990-11-19
Abstract
Abstract An applanation tonometer using a pneumatically driven piston having a sensing tip operated by the gas driving the piston, in which a porous gas bearing serves both as a bearing for the piston and a throttling barrier for gas introduced to drive the piston.
Inventors
- 👤 R Webb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:53
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/16
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
93 words
In an applanation tonomEter having a pneumatically movable piston-hollow cylinder arrangement and a sensing head mounted on said piston and pneumatically coupled with the operating gas in said cylinder, the improvement comprising of a bearing in which said piston is movable, said bearing being porous to said gas and being disposed so as to constitute a throttling means for gas entering said cylinder; and means for providing a gas flow through said bearing and between said piston and cylinder sufficient to lubricate said piston and maintain alignment of said piston in said cylinder.
Claim 2
Dependent Claim
93 words
In an applanation tonomEter having a pneumatically movable piston-hollow cylinder arrangement and a sensing head mounted on said piston and pneumatically coupled with the operating gas in said cylinder, the improvement comprising of a bearing in which said piston is movable, said bearing being porous to said gas and being disposed so as to constitute a throttling means for gas entering said cylinder; and means for providing a gas flow through said bearing and between said piston and cylinder sufficient to lubricate said piston and maintain alignment of said piston in said cylinder.
Claim 3
Dependent Claim
93 words
In an applanation tonomEter having a pneumatically movable piston-hollow cylinder arrangement and a sensing head mounted on said piston and pneumatically coupled with the operating gas in said cylinder, the improvement comprising of a bearing in which said piston is movable, said bearing being porous to said gas and being disposed so as to constitute a throttling means for gas entering said cylinder; and means for providing a gas flow through said bearing and between said piston and cylinder sufficient to lubricate said piston and maintain alignment of said piston in said cylinder.
Claim 4
Dependent Claim
93 words
In an applanation tonomEter having a pneumatically movable piston-hollow cylinder arrangement and a sensing head mounted on said piston and pneumatically coupled with the operating gas in said cylinder, the improvement comprising of a bearing in which said piston is movable, said bearing being porous to said gas and being disposed so as to constitute a throttling means for gas entering said cylinder; and means for providing a gas flow through said bearing and between said piston and cylinder sufficient to lubricate said piston and maintain alignment of said piston in said cylinder.
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) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |