US4520820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic tourniquet with improved pressure resolution
Assignee: Zimmer Surgical Inc
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Filing: 1983-04-15
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Granted: 1985-06-04
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Expires: 2003-04-15
Abstract
Abstract An automatic tourniquet including a mechanism for inflating and deflating a cuff, a pressure sensing mechanism, and a mechanism for displaying the pressure. The pressure sensing mechanism includes a pressure transducer producing a pair of digital signals, and a mechanism for adjusting the signals so that the pressures at which the transitions between the digital quanta occur for one signal are different from the pressures at which the transitions occur for the other signal. The mechanism for adjusting includes a mechanism for setting the signals to be equal at a selected pressure, and a mechanism for offsetting the signals from each other by a voltage corresponding to one-half a digital quantum. The offset signals are summed by a microprocessor to produce a display with twice the resolution of the individual signals.
Inventors
- 👤 Dwight W. Kitchin
- 👤 Michael R. Manes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:34
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/12; A61B17/132; A61B17/135; A61B17/1355; A61H; A61H2201/00; A61H2201/50; A61H2201/5058; A61H2201/5071; A61H2201/5074
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
83 words
A pneumatic tourniquet comprising: means for inflating and deflating a cuff; pressure sensing means for sensing the pressure in said cuff and for producing a plurality of digital signals, each signal representative of said pressure and each signal having a pressure-to-digital signal scale such that the pressures at which the transistions between digital quanta occur are different for each signal; and display means responsive to said plurality of signals for producing a pressure display having greater resolution than each of said digital signals.
Claim 2
Dependent Claim
83 words
A pneumatic tourniquet comprising: means for inflating and deflating a cuff; pressure sensing means for sensing the pressure in said cuff and for producing a plurality of digital signals, each signal representative of said pressure and each signal having a pressure-to-digital signal scale such that the pressures at which the transistions between digital quanta occur are different for each signal; and display means responsive to said plurality of signals for producing a pressure display having greater resolution than each of said digital signals.
Claim 3
Dependent Claim
54 words
A pneumatic tourniquet as in claim 1 wherein there are two of said digital signals, and wherein the transition pressures on the pressure-to-digital signal scale for one signal differ from the transistion pressures on the pressure to digital signal scale for the other signal by a pressure equal to approximately one-half a digital quantum.
Claim 4
Dependent Claim
53 words
A pneumatic tourniquet as in claim 1 wherein said pressure sensing means further comprises a means for adjusting the pressures at which the transistions between contiguous quanta occur for one of the digital signals realtive to the pressures at which the transistions between contiguous quanta occur for the other of the digital signals.
Claim 5
Dependent Claim
27 words
A pneuamtic tourniquet as in claim 1 wherein each of said digital signals is an 8-bit signal and said pressure display has a resolution corresponding to 9-bits.
Claim 6
Dependent Claim
20 words
A pneumatic tourniquet as in claim 4 wherein said pressure display is in mmHg with a resolution of 1 mmHg.
Claim 7
Dependent Claim
34 words
A pneumatic tourniquet as in claim 1 wherein said pressure sensing means comprises: a transducer means for producing a plurality of analog pressure signals; and means for converting said analog signals to digital signals.
Claim 8
Dependent Claim
28 words
A pneumatic tourniquet as in claim 6 wherein said means for converting includes a multiplexing means, and an analog-to-digital converter having an analog input and a digital output.
Claim 9
Dependent Claim
75 words
A pneumatic tourniquet as in claim 7 wherein said display includes: means for storing said signals; and means for reading the signal at said output of said analog-to-digital converter at prescribed times and storing said signals in portions of said storage means corresponding to said prescribed times; and, wherein said multiplexer comprises a means for applying each of said plurality of signals to said input of said analog-to-digital converter at one of said prescribed times
Claim 10
Dependent Claim
36 words
A pneumatic tourniquet as in claim 6 wherein said analog pressure signals are electrical voltage signals, and wherein said means for producing said signals comprises a means for adjusting the relative voltage levels of said signals.
Claim 11
Dependent Claim
37 words
A pneumatic tourniquet as in claim 9 wherein said means for adjusting comprises: means for adjusting said voltages to be substantially equal at a selected pressure; and means for offsetting said voltages with respect to each other.
Claim 12
Dependent Claim
57 words
A pneumatic tourniquet as in claim 10 wherein: said pressure is selected to be the pressure corresponding to substantially one half of the full scale pressure of said pressure transducer means; and said signals are offset by raising said first signal and lowering said second signal by a voltage corresponding to substantially one-fourth of a digital quantum.
Claim 13
Dependent Claim
36 words
A pneumatic tourniquet as in claim 11 wherein said means for producing a pressure display comprises a means responsive to said voltage signals for producing an output signal representative of the combination of the two signals.
Claim 14
Dependent Claim
18 words
A pneumatic tourniquet as in claim 1 and further comprising means for correcting said signals for system errors.
Claim 15
Dependent Claim
45 words
A pneumatic tourniquet as in claim 13 wherein said means for correcting comprises: means for storing the signals produced at a predetermined pressure value; and means communicating with the said means for storing for adjusting said signals by an amount related to said stored signals.
Claim 16
Dependent Claim
15 words
A pneumatic tourniquet as in claim 14 wherein said predetermined pressure is substantially zero pressure.
References Cited (Backward Citations)
WO1983000995A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-03 | 1988-12-03 | 1989-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-03 | 1992-12-03 | 1993-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-03 | 1996-12-03 | 1997-06-04 | $7700.00 | Window Closed / Lapsed |