Abstract A pump particularly suited for use as a prosthetic device in a biological system to replace a pumping component of said system; a novel electro-mechanical transducer; a method for providing a prosthetic pump in a biological system; and method for forming an electrically actuated contractile element for use on a pump. The pump is formed of a resilient sidewalled chamber with exterior and interior surfaces contoured in the shape of the component to be replaced. The walls of the chamber are provided with one or more contractile elements arranged so that upon contraction of said elements the chamber will be contracted. A preferred contractile element is formed of a titanium-nickel alloy such as Nitinol selected from the class of binary equiatomic compounds of transition elements from group IV and group VIII. By arranging the Nitinol secured in a stressed orientation with respect to the chamber wall, subsequent application of current pulses to the wire will produce a heating of the Nitinol wire returning the wire to its original unstressed shape, thereby contracting the the chamber wall to produce pumping. The pump has particular application as an artificial heart.
A pump chamber as in claim 1 in which said flexible walled chamber is a molded plastic material.
Claim 2
Dependent Claim
15 words
A pump chamber as in claim 2 in which said chamber is formed of ethylenevinylacetate.
Claim 3
Dependent Claim
14 words
A pump chamber as in claim 1 in which said contractile element comprises Nitinol.
Claim 4
Dependent Claim
52 words
A pump chamber as in claim 4 in which said element is sinusoidally shaped and annealed at a temperature of between 700* and 1,400* F., with the sinusoidally shaped element stretched at a temperature below the annealing temperature and secured in this stretched condition to said flexible walled chamber in distended condition.
Claim 5
Dependent Claim
25 words
A pump chamber as in claim 5 in which said element is formed of Nitinol having a Temperature Transition Range between 90* and 120* F.
Claim 6
Dependent Claim
26 words
A pump chamber as in claim 5 in which said chamber is of a shape simulating a human organ and is formed of a non-thrombogenic material.
Claim 7
Dependent Claim
68 words
A pump chamber as in claim 7 in which said contractile element comprises a Nitinol wire having a Temperature Transition Range between 90* and 120* F. having a sinusoidal shape and annealed at a temperature of over 700* F. and secured with respect to the chamber wall in a stretched orientation at a temperature below 700* F. to separate the undulations of the annealed sinusoidally shaped Nitinol wire.
Claim 8
Dependent Claim
51 words
A pump chamber as in claim 7 in which said contractile element comprises in addition to said annealed sinusoidally shaped Nitinol wire, a strip of Nitinol annealed at a temperature above 700* F. and secured with respect to the chamber wall in a stretched orientation at a temperature below 700* F.
Claim 9
Dependent Claim
92 words
A method for utilizing the pump chamber as formed in claim 7 comprising the steps of surgically removing the pumping organ from the mammalian body which is to have the pumping organ replaced; connecting the chamber to the fluid conducting ducts to which the removed organ had been connected positioning the pump chamber in place of the removed organ; and connecting the ends of the Nitinol material secured to the chamber to a source of electrical energy providing pulses of electrical energy timed to simulate the pumping pulses of the replaced organ.
Claim 10
Dependent Claim
42 words
A method as in claim 10 in which the Nitinol material is provided in a plurality of spaced arrays on the pump chamber; and said arrays are electrically energized in a timed sequence to contract different portions of the pump chamber sequentially.