Thumb pitch compensating span gauge
US4257165A · kind A · utility
Inventor
Key dates
| Filing date | Jun 13, 1979 |
| Grant date | Mar 24, 1981 |
| Priority date | — |
| Expiry date | Jun 13, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B5/0023
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A span gauge for measuring the distance between a thumb hole and a finger hole on a bowling ball comprised of a plate having a curved edge fitting the contour of the bowling ball and an angle positioning post pivotally attached to the edge of the plate. The radius of curvature on the curved edge is equal to the radius of curvature of the surface of the bowling ball and the pivoting post is attached to one end of the curved edge. A calibrated scale on the curved edge permits measurement by inserting the pivoted post in a pre-drilled thumb hole to determine the point at which the finger hole is to be drilled. The pivoted post allows the span gauge to compensate for the pitch angle of pre-drilled thumb holes which may vary from ball to ball.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.