A digitial electronic foot pedal control system, especially for medical apparatus and the like having a plurality of operating functions which can be selected among, comprises a pivotally mounted pedal shaft and a foot-operated pedal fixed to the shaft to pivot therewith. Included are a shaft encoder connected to the shaft for producing a digital shaft position output signal indicative of pedal shaft position relative to a reference position and a plurality of address cards each having N addresses corresponding to N given shaft positions. Each address card corresponds to one or more medical apparatus functions and is selected when a corresponding function or functions are selected, each of the addresses on each address card corresponding to a particular shaft rotational position and each storing a given set of control output signals for operating the corresponding function or functions. A counter counts the shaft position output signal from the encoder; address pointers derived from the count are applied to the appropriate address card to thereby cause the outputting therefrom of the appropriate sets of control signals as the foot pedal shaft is rotated. A stepper motor is connected for driving the shaft in a rotational direction toward the shaft reference position when the shaft is displaced therefrom and when the stepper motor is energized by an appropriate control signal, thereby providing a resistance to, but not preventing, further pedal rotational movement away from the reference position so as to provide tactile information regarding pedal position and possible changes in apparatus function.

A linking mechanism for irrigation/aspiration machines which includes a coupling member having a plug that is inserted into an opening in a receptacle on the face of the I/A machine. The plug projection is sealed in air tight relation to the wall surrounding the opening and an auxiliary prong(s) prevent rotation of the plug as well as lock the plug in the receptacle. The receptacle includes an arming switch activated responsive to proper seating of the plug in the receptacle to arm the peristaltic pump that is subsequently operated by a foot switch to generate a vacuum in the aspirant line.

A pneumatic pressure delivery system capable of delivering negative pressure (vacuum or suction) or positive pressure with a precise, continuously variable and predictable control of the pressure delivered is disclosed. The method and apparatus includes the capability of electronically adjusting the variation of pressure to follow any desirable functional mathematical relationship of a control signal. The apparatus includes an electronically controlled pressure regulator in which the pressure at the outlet of a regulator acts upon a piston or diaphragm in opposition to a force produced by an electronic controller. The piston or diaphragm is mechanically coupled to a flow control valve such that the valve alters its position to increase or decrease the flow to its outlet in response to the force exerted on the piston or diaphragm. The invention is also directed toward an aspiration method and apparatus which includes a cassette and a cassette holder to be used in conjunction with the suction and pressure control system. The aspiration method and apparatus utilizes a first chamber having a flexible diaphragm to communicate vacuum to an aspiration port which is connected to a surgical instrument. When the first chamber is nearly filled to capacity, fluid within the first chamber is transferred to a second larger chamber through the application of pressure to the flexible diaphragm. A pair of pinch valves prevents vacuum from being applied to the second chamber and pressure from being applied to the aspiration port.

A pneumatic pressure delivery system capable of delivering negative pressure (vacuum or suction) or positive pressure with a precise, continuously variable and predictable control of the pressure delivered is disclosed. The method and apparatus includes the capability of electronically adjusting the variation of pressure to follow any desirable functional mathematical relationship of a control signal. The apparatus includes an electronically controlled pressure regulator in which the pressure at the outlet of a regulator acts upon a piston or diaphragm in opposition to a force produced by an electronic controller. The piston or diaphragm is mechanically coupled to a flow control valve such that the valve alters its position to increase or decrease the flow to its outlet in response to the force exerted on the piston or diaphragm. The invention is also directed toward an aspiration method and apparatus which includes a cassette and a cassette holder to be used in conjunction with the suction and pressure control system. The aspiration method and apparatus utilizes a first chamber having a flexible diaphragm to communicate vacuum to an aspiration port which is connected to a surgical instrument. When the first chamber is nearly filled to capacity, fluid within the first chamber is transferred to a second larger chamber through the application of pressure to the flexible diaphragm. A pair of pinch valves prevents vacuum from being applied to the second chamber and pressure from being applied to the aspiration port.

A surgical cassette unloading and unloading system having a peristaltic pump roller head with a flared and beveled notch and a plunger or probe that engages the cassette peristaltic pump tube.