US3896794A — Venous flow stimulator

Claim 1

Independent Claim 147 words

An apparatus useable in conjunction with a source or pressurized gas for stimulating venous blood flow in the legs of patients undergoing surgery, said apparatus including at least one double-walled pneumatic boot positioned on and completely enclosing a patient''s leg and foot; said boot having an operating space defined between the walls thereof; a supply valve operative to control the supply of gas at a suitable pressure from a pressurized source to the operating space; means responsive to the gas pressure in the operating space for closing the supply valve when the pressure reaches a chosen maximum valve; a timer means adapted to produce a series of successive set and reset pulses, and an inlet valve means, controlled by the timer, for supplying gas to the supply valve upon receipt of a set pulse, and for discontinuing the supply of gas upon receipt of a reset pulse.

Claim 2

Independent Claim 147 words

An apparatus useable in conjunction with a source or pressurized gas for stimulating venous blood flow in the legs of patients undergoing surgery, said apparatus including at least one double-walled pneumatic boot positioned on and completely enclosing a patient''s leg and foot; said boot having an operating space defined between the walls thereof; a supply valve operative to control the supply of gas at a suitable pressure from a pressurized source to the operating space; means responsive to the gas pressure in the operating space for closing the supply valve when the pressure reaches a chosen maximum valve; a timer means adapted to produce a series of successive set and reset pulses, and an inlet valve means, controlled by the timer, for supplying gas to the supply valve upon receipt of a set pulse, and for discontinuing the supply of gas upon receipt of a reset pulse.

Claim 3

Dependent Claim 64 words

A venous flow stimulator as claimed in claim 1, including injector means positioned downstream of the supply valve between the supply valve and boot for receiving high-pressure gas from the open supply valve and for diluting it with atmospheric air thereby producing a larger volume of gas at lower pressure for feeding to the pneumatic boot as long as the supply valve is open.

Claim 4

Dependent Claim 34 words

A venous flow stimulator as claimed in claim 1, including means for energizing the timer only when the pressure of the supply of gas to the said inlet valve is above a chosen minimum.

Claim 5

Dependent Claim 23 words

A venous flow stimulator as claimed in claim 3, in which the timer is electronic and is composed of units of integrated circuitry.

Claim 6

Dependent Claim 39 words

A venous flow stimulator as claimed in claim 1, in which the said supply valve includes a magnetic rocker valve and two permanent magnets mounted for relative movement, said rocker valve being operated by relative movement of said magnets.

Claim 7

Dependent Claim 52 words

A venous flow stimulator as claimed in claim 5, in which the said supply valve includes a bellows having a portion thereof movable relative to said rocker valve, said movable portion carrying one of the said two permanent magnets for movement thereof toward and away from actuating relationship with the rocker valve.

Claim 8

Dependent Claim 29 words

A venous flow stimulator as claimed in claim 6, including an adjustable bleed valve in the bellows, said bleed valve venting the bellows to atmosphere at a desired rate.

Claim 9

Dependent Claim 72 words

A venous flow stimulator as claimed in claim 1, including an exhaust valve biased to the open position, said exhaust valve being operatively controlled by the outlet pressure of the gas From the supply valve in a manner whereby when the outlet pressure exceeds a chosen valve the exhaust will close, the inlet of the exhaust valve being in communication with the operating space of the boot for a selective venting thereof.

Claim 10

Dependent Claim 21 words

A venous flow stimulator as claimed in claim 4, in which the timer produces set and reset pulses of opposite polarity.

Claim 11

Dependent Claim 36 words

A venous flow stimulator as claimed in claim 9, in which the intervals between successive set and reset pulses is approximately 10 seconds, and between successive reset and set pulses is approximately 100 - 120 seconds.

Claim 12

Dependent Claim 44 words

A venous flow stimulator as claimed in claim 10, in which shunted across input terminals of the timer is a capacitor adapted to be discharged through the timer to contribute energy to the pulses, and to be charged in the intervals between the pulses.

Claim 13

Independent Claim 64 words

The method of stimulating venous blood flow in the leg of a patient undergoing surgery comprising intermittently forcing blood from the veins of the leg by an intermittent pressurization of a leg and foot encasing pneumatic boot at an increasing rate of 8 mm of mercury per second to a maximum on the order of 50 mm of mercury, and subsequently releasing the pressure.

Claim 14

Independent Claim 64 words

The method of stimulating venous blood flow in the leg of a patient undergoing surgery comprising intermittently forcing blood from the veins of the leg by an intermittent pressurization of a leg and foot encasing pneumatic boot at an increasing rate of 8 mm of mercury per second to a maximum on the order of 50 mm of mercury, and subsequently releasing the pressure.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-07-28	1979-01-27	1979-07-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-07-28	1983-01-27	1983-07-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-07-28	1987-01-27	1987-07-29	$7700.00	Window Closed / Lapsed

Venous flow stimulator

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