Gerber variable scale
Date: circa 1950
Inventory Number: 2003-1-0185
Classification: Scale (Ruler)
Subject:
Maker: Gerber Scientific Inc. (1948-present)
Cultural Region:
Place of Origin:
Dimensions:
scale rule: 1.1 × 30.6 × 3.9 cm (7/16 × 12 1/16 × 1 9/16 in.)
box: 2.8 × 32.6 × 7.1 cm (1 1/8 × 12 13/16 × 2 13/16 in.)
Material:
Accessories: light brown leatherette box, with black velveteen lining and snap closure
Description:
Black aluminum rectangle, to which two aluminum strips, also black, are screwed. Two scales are printed on the bottom strip. Along the bottom edge of the strip is an inverted logarithmic scale "R", with values descending from 100 to 10. Above this is a scale "I" in inches, graduated into twentieths.
The aluminum caps at either ends of the main assemby (rectangle and two strips) are painted silver. Also painted silver is the L-shaped runner which moves to left and right along the groove between the two black strips. A rectangular piece of clear plastic with a vertical indicating line is screwed to the bottom of the runner, so that it sits directly over scales "I" and "R".
A triangular spring streches between the left end cap and the top of the runner. Every fifth coil is painted green or red, in an alternating pattern. The fiftieth coil from the left is painted gold.
The instrument is stored in a light brown leatherette box with black velveteen lining and snap closure.
The aluminum caps at either ends of the main assemby (rectangle and two strips) are painted silver. Also painted silver is the L-shaped runner which moves to left and right along the groove between the two black strips. A rectangular piece of clear plastic with a vertical indicating line is screwed to the bottom of the runner, so that it sits directly over scales "I" and "R".
A triangular spring streches between the left end cap and the top of the runner. Every fifth coil is painted green or red, in an alternating pattern. The fiftieth coil from the left is painted gold.
The instrument is stored in a light brown leatherette box with black velveteen lining and snap closure.
Signedtop aluminum strip, center: GERBER VARIABLE SCALE ;
top aluminum strip, bottom left: THE GERBER SCIENTIFIC INSTRUMENT CO. HARTFORD, CONN. ;
inside box lid: THE GERBER SCIENTIFIC INSTRUMENT COMPANY / HARTFORD, CONNECTICUT
top aluminum strip, bottom left: THE GERBER SCIENTIFIC INSTRUMENT CO. HARTFORD, CONN. ;
inside box lid: THE GERBER SCIENTIFIC INSTRUMENT COMPANY / HARTFORD, CONNECTICUT
Inscribedtop aluminum strip, bottom right: MODEL TP-007 PAT'S PEND. MADE IN U.S.A.
FunctionFor measuring or transferring distances at a variety of scales.
The user first moves the runner to left or right such that the runner's indicating line falls over the desired total length of the spring ("I" scale) or the desired number of parts per inch ("R" scale). Then he places the spring along the length to be measured, and reads the measurement in numbers of coils.
This is an early version of the Gerber Variable Scale. In later editions a third scale, "L_10", was added to the bottom aluminum piece, and the triangular spring was encased in plastic crystal to facilitate reading at the edge of the instrument. A second, circular spring attached to the triangular spring was also added. This spring was marked with numbers to make reading the total length easier. See this website for comparison.
The user first moves the runner to left or right such that the runner's indicating line falls over the desired total length of the spring ("I" scale) or the desired number of parts per inch ("R" scale). Then he places the spring along the length to be measured, and reads the measurement in numbers of coils.
This is an early version of the Gerber Variable Scale. In later editions a third scale, "L_10", was added to the bottom aluminum piece, and the triangular spring was encased in plastic crystal to facilitate reading at the edge of the instrument. A second, circular spring attached to the triangular spring was also added. This spring was marked with numbers to make reading the total length easier. See this website for comparison.
Historical AttributesThe Gerber Variable Scale was the first instrument sold by Gerber Scientific. It was invented around 1945 by company founder Joseph Gerber, who was then a junior at Rensselaer Polytechnic Institute. Gerber constructed his first variable scale from the elastic in his pajama bottoms. See this website for the story.
Curatorial RemarksAlso see the Gerber GraphAnalogue, 2003-1-0234, a later version of the variable scale.
Primary SourcesGerber, H. Joseph. The Gerber Variable Scale: An Application and Instruction Manual. Hartford, CT: Gerber Systems Inc, 1953. Available for download here.
ProvenancePrivate Donor, Troy, New York.
