Ruler with magnifying cursor

• US 4,757,616 A
• Filed: 10/26/1987
• Issued: 07/19/1988
• Est. Priority Date: 10/26/1987
• Status: Expired due to Fees

• Current Assignee: Educational Insights Incorporated (Learning Resources, Inc.)
• Original Assignee: Educational Insights Incorporated (Learning Resources, Inc.)
• Inventors: Hills, Brian
• Primary Examiner(s): HAROIAN, HARRY
• Application Number:
  US07/112,403
• Time in Patent Office: 267 Days
• Field of Search: 33/488, 350/114, 350/115, 350/116
• US Class Current: 33/488
• CPC Class Codes: G01B 3/04 rigid

Abstract

A ruler for use in the measurement of distances on a flat surface is disclosed herein, having an elongated base with raised edge marginal regions defining a T-shaped recess therebetween. A first edge marginal region displays a plurality of analog measurement increments in the form of transverse marked lines while numerical indicia associated with each line increment is carried at the bottom of the recess. A cursor having an inverted T-shaped portion is slidably engaged with the base T-shaped recess. The cursor further includes a guide rail on one side frictionally engaged with a track provided on a second one of the edge marginal regions while cantilevered finger having an index line thereon projects over the first edge marginal region for selected registration with the end of an object being measured. An enlarged semicircular magnifier is carried on the cursor midway between its opposite sides for visually enlarging numerical indicia associated with a measurement line mark selected by registration of the index line therewith.

Claims

1. A measuring device for determining the length of an object or distance comprising the combination of:

an elongated base having a central recess separated by a pair of edge marginal regions having opposing wall surfaces defining said central recess;

said base recess characterized as a T-shaped recess having a pair of opposing slots in said wall surfaces of said respective edge marginal regions;

a first one of said edge marginal regions having a plurality of line increment marks as a measurement scale carried along a straight edge against which the object or distance is measured;

two rows of staggered numerical indicia of different fractional values carried on said base at the bottom of said recess and each numerical fractional value assocated with and aligned with a particular line increment mark of said measurement scale;

a cursor composed of transparent material movably carried on said base and having an index marker carried on a cantilevered finger over said measurement scale adapted to be registered with a selected one of said line increment marks at the end of the object or distance to be measured;

said cursor further having a magnifying means centrally disposed thereon in linear alignment with said index marker and immediately about said recessed display of numerical indicia whereby alignment of said index marker with selected line increment marks reveals an enlarged display of a selected numerical indicia of a given fractional value; and

framing means carried on said cursor on either side of said magnifying means for obscuring non-selected numerical indicia.

2. The invention as defined in claim 1 including:

guide means interconnecting said cursor with said base to stabilize and guide said cursor along the length of said base.

3. The invention as defined in claim 2 wherein:

said guide means includes an open and exposed track disposed on the second edge marginal region of said pair and a rail fixedly carried on said cursor disposed in said track.

4. The invention as defined in claim 3 including:

means for slidably mounting said cursor on said base comprising a tongue-in-groove arrangement wherein said base recess is characterized as an inverted T-shaped recess having a pair of opposing slots provided in said wall surfaces of said respective edge marginal regions;

said mounting means further including foot portions outwardly projecting from said cursor insertable into said pair of slots in sliding relationship.

5. The invention as defined in claim 4 wherein:

said magnifying means includes a rounded surface on the top thereof and an optically flat surface on the underside in center alignment with said rounded surface.