US3675243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic drip timing device
Assignee: Illinois Tool Works Inc
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Filing: 1970-01-22
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Granted: 1972-07-04
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Expires: 1990-01-22
Abstract
Abstract Electronic timing device for timing drips in intravenous feeding and similar systems can be adjusted to provide an audible or visible signal in accordance with any desired drip rate between about 4 and 300 drips per minute. The device overcomes the inherent deficiency of conventional electronic metronomes which are unsuitable for adjusting drip rates since they have a first pulse period different from the remainder. The first pulse period is of the exact length of the remaining pulse periods due to the presence of a circuit which can be maintained in a standby condition with its capacitor partially charged. This permits the pulse producing circuit to be actuated simultaneously with the visual observance by an operator of a drip passing a predetermined point. If the actual drop rate is different from the desired rate, the operator adjusts it and again actuates the timing device. This operation is repeated until the timing rate and the drip rate are synchronized. The device is battery operated and sufficiently small as to be easily carried around the neck or in the pocket of the person using it.
Inventors
- 👤 John F Landuyt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:08
CPC Classifications
G; G04; G04F; G04F5/00; G04F5/02; G04F5/025; A; A61; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/16886; A61M5/1689; A61M2209/00; A61M2209/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
183 words
A device for producing a plurality of pulses having a period between pulses of a selected predetermined length comprising a relaxation oscillator circuit including a capacitor and a plurality of resistance members in series in a signalling means which have a time period of a predetermined length in accordance with the equation: t RC 1n VB - Vo/VB - Vc where: t time R series resistance C capacitance VB battery voltage VC capacitor voltage Vo initial capacitor voltage primary switch means for connecting the battery to close said oscillator circuit; reset resistance means and reset switch means operable for selectively connecting said reset resistance means in said closed circuit in parallel connection with said capacitor and shunting one of said plurality of resistance members which has a greater value of resistance, said reset resistance means having a resistance value sufficiently low to prevent said circuit from oscillating to produce pulses while maintaining the voltage across the capacitor at a constant value equal to the value Vo which it has when the reset switch is open and the circuit is oscillating to produce pulses.
Claim 2
Independent Claim
183 words
A device for producing a plurality of pulses having a period between pulses of a selected predetermined length comprising a relaxation oscillator circuit including a capacitor and a plurality of resistance members in series in a signalling means which have a time period of a predetermined length in accordance with the equation: t RC 1n VB - Vo/VB - Vc where: t time R series resistance C capacitance VB battery voltage VC capacitor voltage Vo initial capacitor voltage primary switch means for connecting the battery to close said oscillator circuit; reset resistance means and reset switch means operable for selectively connecting said reset resistance means in said closed circuit in parallel connection with said capacitor and shunting one of said plurality of resistance members which has a greater value of resistance, said reset resistance means having a resistance value sufficiently low to prevent said circuit from oscillating to produce pulses while maintaining the voltage across the capacitor at a constant value equal to the value Vo which it has when the reset switch is open and the circuit is oscillating to produce pulses.
Claim 3
Dependent Claim
84 words
The device as described in claim 1 wherein said reset switch means is operative when actuated in one mode to connect said reset resistance in said circuit in parallel connection with said capacitor and to remove said one of said plurality of resistance members from series connection with said capacitor, said switch being operative when actuated in another mode to remove said reset resistance from said circuit and to restore said one of said plurality of resistance members to series connection with said capacitor.
Claim 4
Dependent Claim
37 words
The device as described in claim 2 wherein said one of said plurality of resistance members comprises variable resistance means for varying the value of the series resistance R and thus the time t in said equation.
Claim 5
Dependent Claim
40 words
The device as described in claim 2 wherein said reset switch means comprises a momentary switch having a spring biased actuator witch is depressed to be actuated in said one mode and released to be actuated in said other mode.
Claim 6
Dependent Claim
25 words
The device of claim 3 wherein said primary switch means and said variable resistance means are operatively interconnected for actuation by a common control member.
Claim 7
Dependent Claim
17 words
The device of claim 1 wherein said signalling means includes a speaker for producing an audible sound.
Claim 8
Dependent Claim
56 words
The device of claim 2 wherein said oscillator circuit includes a transistor connected in fixed parallel relation to said capacitor and operative to trigger the discharge of said capacitor only when said reset switch is in said other mode and said transistor and capacitor are at a predetermined voltage in excess of said capacitor voltage V.
Claim 9
Dependent Claim
41 words
The device of claim 7 wherein a speaker is connected in series with said transistor, said capacitor being in parallel with said series connected transistor and speaker, said speaker producing an audible sound pulse when said capacitor discharges through said transistor.
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) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |