Paul A Fischer

US Patent:

53478940, Sep 20, 1994

Filed:

May 28, 1993

Appl. No.:

8/069160

Inventors:

Paul D. Fischer - Bloomington MN

Assignee:

PMT Corporation - Chanhassen MN

International Classification:

B25B 23153

US Classification:

81471

Abstract:

The present invention relates to a torque limiting device for use in the affixation of a halo-type traction tool to the skull of a person. The torque limiting device has a shaft or shank embedded in a handle member which rotatably engages a skull pin during the fixation of a halo-type traction device to an individual. The torque limiting device has a first shear point at a reduced shank intermediate portion which prevents rotational torque forces in excess of a predetermined level from being applied to a skull pin during the attachment procedure of a medical cervical traction brace or tool. The present invention also includes a second shear point at the shank-handle interface which acts as a second safety mechanism to ensure that excessive pressure is not applied, and undesirable skull penetration does not occur, during the attachment procedure of a skull pin and halo to an individual's skull. The torque limiting device further includes a skull pin engaging end. The handle encapsulates a substantial portion of the shank, including the first and second shear points, and a handle-shank interface retaining collar and groove arrangement from which the pin engaging end extends also from the handle.

US Patent:

44848609, Nov 27, 1984

Filed:

May 17, 1982

Appl. No.:

6/379256

Inventors:

David L. Brenholt - Menomonie WI
Paul M. Fischer - Apple Valley MN
Kenneth V. Mattson - Menomonie WI

Assignee:

Donaldson Company, Inc. - MN

International Classification:

F04D 2920

US Classification:

416182

Abstract:

A radial tube centrifugal fan is disclosed. The fan is assembled from a first mating half (12) having a planar backing plate (16) with a group of half tubes (52) extending in spoke-like fashion from the plate and separated by webbing members (56), attached to a second mating half (14) having an axial inlet opening (18) and a like group of half tubes (54) and webbing members (58). The assembled fan has an inlet port (18) and a plurality of radially extending outlet tubes (26) formed from the mating half tubes and which are curved in a direction away from the preferred direction of fan rotation.