Portable teaching aid


FIG. 1 is a front perspective view of a portable teaching aid showing my new design in operating open or expanded position;

FIG. 2 is a side elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a view in elevation of the opposite side of FIG. 1; and

FIG. 5 is a perspective view of the teaching aid in closed position.

Referenced Cited
U.S. Patent Documents
3345760 October 1967 Myhr
Foreign Patent Documents
60727 March 1943 DK
458623 July 1950 IT
Patent History
Patent number: D252758
Type: Grant
Filed: May 2, 1977
Date of Patent: Aug 28, 1979
Inventor: Lester E. Prall (Salt Lake City, UT)
Primary Examiner: Melvin B. Feifer
Attorney: W. Britton Moore
Application Number: 5/793,162