Douglas W Ritchie

US Patent:

42379350, Dec 9, 1980

Filed:

Dec 14, 1978

Appl. No.:

5/969609

Inventors:

Julian Delmonte - La Canada CA
M. Janet Kirkwood - Montebello CA
Douglas G. Ritchie - Pasadena CA

Assignee:

Eaton Corporation - Cleveland OH

International Classification:

F16K 1514

US Classification:

137860

Abstract:

A body of electrically insulating material contains a passageway extending completely through the body. The passageway includes a flexible diaphragm dividing the passageway into two compartments to isolate a transducer placed on one side of the diaphragm from direct contact with fluid contained on the opposite side. A pressure relief port, passing from one side of the body to the passageway on the fluid side of the diaphragm, is covered with an "O" ring. Excessive fluid pressure forces the "O" ring away from the relief port to vent the pressure and thereby prevent damaging the transducer.

US Patent:

42379008, Dec 9, 1980

Filed:

Feb 14, 1979

Appl. No.:

6/012142

Inventors:

Joseph H. Schulman - Los Angeles CA
Douglas G. Ritchie - Pasadena CA

Assignee:

Pacesetter Systems, Inc. - Sylmar CA

International Classification:

A61B 500

US Classification:

128630

Abstract:

An implantable body transducer having a self-contained calibration means. An exemplary embodiment comprises an implantable body pressure measuring transducer utilizing an L-C oscillator having a resonant circuit comprising a fixed L and a variable C, the variable C having a fixed capacitive electrode and a movable capacitive electrode in the form of a stiff pressure responsive diaphragm, the output frequency of the oscillator being a function of the pressure sensed by the diaphragm. The transducer incorporates a self-contained calibration means which contains predetermined calibration data with respect to the variable C. The predetermined calibration data is stored in a plurality of PROM storage elements which are sequentially addressed in accordance with the output of a counter, the PROM storage elements providing a serial bit stream which can be used to pulse-code modulate the L-C resonant circuit output. Specific calibration parameters for the variable C are determined during manufacture of the pressure measuring transducer. These parameters are programmed into the digital storage elements of the PROM, burned in, and then utilized to modulate the resonant circuit output subsequent to implantation in a body.

US Patent:

51766620, Jan 5, 1993

Filed:

Aug 23, 1990

Appl. No.:

7/572924

Inventors:

Gerald Bartholomew - Sherman Oaks CA
Douglas G. Ritchie - Pasadena CA

Assignee:

Minimed Technologies, Ltd. - Sylmar CA

International Classification:

A61M 500

US Classification:

604283

Abstract:

An improved subcutaneous injection set is disclosed which has a soft cannula for subcataneous delivery of a selected medication to a patient. The cannula is supported by and protrudes outwardly from a cylindrical support hub of a housing adapted to receive the selected medication. A flanged base end of the cannula is disposed within the housing and is captured by a swaged lock rim to retain a sealing gasket under compression against an annular seat within the support hub, thereby preventing leakage of the medication through the hub and about the exterior of the cannula.