Cardiographic apparatus with stylus control means

Claim 2

A cardiographic device including transducer means for converting the heart action into electric signals representative of such heart action; a stylus; record means operatively associated with said stylus for producing a record of the travel of said stylus across said record means; bidirectional motor means connected to said stylus for moving said stylus in first and second directions across said record means; and circuit means responsive to the amplitude of said electric signals for moving said motor means through a distance proportional to the amplitudes of said electric signals; said circuit means including first switch means connected to said transducer means and being operable from a first to a second state in response to said electric signals from said transducer means to provide for the flow of current through said motor means in a first direction corresponding to movement of the stylus in said first direction, and second switch means connected to said first switch means and being operable from a first to a second state in response to the movement of said first switch means to the first state to provide for the flow of current through said motor means in the opposite direction corresponding to movement of the stylus in said second direction.

Claim 3

A cardiographic device as in claim 1, in which said motor means includes a threaded shaft, a motor drivingly connected with said shaft whereby said motor is adapted to rotate said shaft in opposite directions in accordance with the direction of current flow through said motor, said stylus includes means threadedly engaging said shaft whereby the rotational motion of said shaft is converted to a linear motion of said stylus.

Claim 4

A cardiographic device as in claim 1, in which said record means includes a web of graph paper positioned adjacent said stylus, and selectively operable driving means for moving said web relative to said stylus.

Claim 5

A cardiographic device as in claim 1, and biasing means connected to said circuit means for biasing said motor means to a null position corresponding to a preselected position of said stylus.

Claim 6

A cardiographic device as in claim 4, in which said biasing means includes a potentiometer having an arm connected to said stylus and movable therewith, opposite polarity sources of energy connected to each end of said potentiometer, whereby movement of said stylus causes said potentiometer arm to move toward one of said sources of energy to cause movement of said first switch means to said second state.

Claim 7

A cardiographic device including transducer means for converting the heart action into electric signals representative of such heart action; a stylus; record means operatively associated with said stylus for producing a record of the travel of said stylus across said record means; bidirectional motor means connected to said stylus for moving said stylus in first and second directions across said record means; and circuit means responsive to the amplitude of said electric signals for moving said motor means through a distance proportional to the amplitudes of said electric signals; said circuit means including first switch means operable from a first to a second state in response to said electric signals to provide for the flow of current through said motor means in a first direction corresponding to movement of the stylus in said first direction, and second switch means operable from a first to a second state in response to the movement of said first switch means to the first state to provide for the flow of current through said motor means in the opposite direction corresponding to movement of the stylus in said second direction, said first switch means including a first normally nonconducting, a second normally conducting and a third normally nonconducting transistor having an opposite conductivity from said first and second transistors; said second and third transistors being connected in series and to said first transistor whereby said second transistor is nonconducting and said third transistor conducts when said first transistor is conducting; said second switch means including a fourth normally conducting, a fifth normally nonconducting and a sixth normally conducting transistor, said sixth transistor having said opposite conductivity; said fifth and sixth transistors being connected in series and to said fourth transistor whereby said fifth transistor is conducting and said sixth transistor is nonconducting when said fourth transistor is nonconducting; lead means connecting said second and fourth transistors and said fourth transistor being responsive to said second transistor whereby said fourth transistor is rendered conductive when said second transistor conducts, and said motor being connected between the second and third transistors at one end and the fifth and sixth transistors at the other end.

Claim 8

A cardiographic device including transducer means for converting the heart action into electric signals representative of such heart action; a stylus; record means operatively associated with said stylus for producing a record of the travel of said stylus across said record means; bidirectional motor means connected to said stylus for moving said stylus in first and second directions across said record means; and circuit means responsive to the amplitude of said electric signals for moving said motor means through a distance proportional to the amplitudes of said electric signals; said circuit means including first switch means operable from a first to a second state in response to said electric signals to provide for the flow of current through said motor means in a first direction corresponding to movement of the stylus in said first direction, and second switch means operable from a first to a second state in response to the movement of said first switch means to the first state to provide for the flow of current through said motor means in the opposite direction corresponding to movement of the stylus in said second direction, said first switch means including a first normally nonconducting, a second normally conducting and a third normally nonconducting transistor having an opposite conductivity from said first and second transistors; said second and third transistors being connected in series and to said first transistor whereby said second transistor is nonconducting and said third transistor conducts when said first transistor is conducting; said second switch means including a fourth normally conducting, a fifth normally nonconducting and a sixth normally conducting transistor, said sixth transistor having said opposite conductivity; said fifth and sixth transistors being connected in series and to said fourth transistor whereby said fifth transistor is conducting and said sixth transistor is nonconducting when said fourth transistor is nonconducting; lead means connecting said second and fourth transistors and said fourth transistor being responsive to said second transistor whereby said fourth transistor is rendered conductive when said second transistor conducts, and said motor being connected between the second and third transistors at one end and the fifth and sixth transistors at the other end.

Claim 9

A cardiographic apparatus as in claim 6, and biasing means for normally biasing said first transistor so that it hunts about the conduction-nonconduction point.