MAGNIFYING INDICATOR FOR A BURETTE

• US 3,762,799 A
• Filed: 08/27/1971
• Issued: 10/02/1973
• Est. Priority Date: 08/27/1971
• Status: Expired due to Term

• Current Assignee: Justin Joel Shapiro
• Original Assignee: Justin Joel Shapiro
• Inventors: Shapiro, Justin Joel
• Primary Examiner(s): Corbin, John K.
• Application Number:
  US05/175,640
• Time in Patent Office: 767 Days
• Field of Search: 350/110-116,243,244,190,191
• US Class Current: 359/442
• CPC Class Codes: B01L 3/0203 Burettes, i.e. for withdrawing and redistributing liquids through different conduits
• CPC Class Codes: G01B 9/00 Measuring instruments characterised by the use of optical techniques

Abstract

A magnifying scale indicator for a burette wherein the indicator is adjustably mounted on a depending rod extending parallel to the scale on the burette. The indicator consists of an arcuate transparent lens bar which is a segment of an annular ring. The indicator lens bar has paired fiducial lines on opposite sides thereof and can be adjusted toward and away from the burette to vary the magnification of the burette scale. The paired fiducial lines permits this variable magnification without parallax error.

Claims

1. In a burette, a barrel, a scale on said barrel, an indicator support rod extending adjacent said barrel and parallel to said scale, a transparent magnifying lens bar, means connecting said lens bar to said support rod so that the lens bar transversely overlies said scale, and longitudinal fiducial line means on said lens bar for indicating a linear region on a magnified portion of the scale visible through said lens bar, wherein said barrel contains a movable plunger and said indicator support rod is rigidly connected to said plunger.

2. The burette of claim 1, and wherein said fiducial line means comprises a first fiducial line on the outer surface of said transparent lens bar and a second fiducial line on the inside surface of said transparent lens bar parallel to said first fiducial line, said linear region of the scale being in line with the two fiducial lines.

3. The burette of claim 2, and wherein said lens bar has a bore slidably and rotatably receiving said support rod, and said means connecting the lens bar to the support rod comprises a rotary clamping element on the lens bar clampingly engageable with said support rod.

4. The burette of claim 3, wherein said bore is located adjacent one end of said lens bar.

5. The burette oF claim 4, and wherein said lens bar is arcuately curved and is substantially conformable in shape to said barrel at its inside surface.

6. The burette of claim 5, and wherein said lens bar is substantially bevelled at its inside corner adjacent the support rod to provide clearance for adjusting the lens bar outwardly from the barrel.

7. The burette of claim 5, and wherein said lens bar is a segment of an annular ring of transparent material.

8. The burette of claim 5, and wherein said lens bar has a spherically convex outer lens surface and a substantially cylindrical concave inner lens surface, said fiducial lines being located in a common central plane of the lens bar extending normal to the axis of said cylindrical inner lens surface.

9. The burette of claim 8, and wherein the axis of said rotary clamping element is located substantially in said common central plane of the lens bar.