David L Canfield

US Patent:

8155997, Apr 10, 2012

Filed:

Feb 25, 2003

Appl. No.:

10/504668

Inventors:

David A. Canfield - Chicago IL, US

International Classification:

G06F 17/30

US Classification:

705 738

Abstract:

Methods and systems consistent with the present invention provide a performance tracking tool that receives an identification of a data item (), associates the data item with one of a group of tracking modes () that includes at least two of a LOGICAL mode, a SUM mode, and an AVERAGE mode.

US Patent:

40931200, Jun 6, 1978

Filed:

Jan 24, 1977

Appl. No.:

5/761703

Inventors:

David L. Canfield - Libertyville IL

Assignee:

Park Rubber Company - Lake Zurich IL

International Classification:

E01C 904

US Classification:

238 8

Abstract:

A railroad crossing structure comprising one or more elastomeric pads which preferably have a flexible plate of a concave cross-section imbedded within them. The elastomeric pads are abutted together side-by-side and/or end-to-end to form the crossing, and the abutting edges thereof are formed with interlocking means to provide moisture-proof seams between them. The elastomeric pads are secured in place by means of rods extended longitudinally through them, with the ends of the rods being secured to anchor means.