| US 7,571,552 B2 | ||
| Scale reading apparatus | ||
| Simon Eliot McAdam, Bristol (United Kingdom) | ||
| Assigned to Renishaw PLC, Wotton-Under-Edge (United Kingdom) | ||
| Appl. No. 11/629,854 PCT Filed Jul. 06, 2005, PCT No. PCT/GB2005/002652 § 371(c)(1), (2), (4) Date Dec. 18, 2006, PCT Pub. No. WO2006/003452, PCT Pub. Date Jan. 12, 2006. |
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| Claims priority of application No. 0415141.1 (GB), filed on Jul. 06, 2004. | ||
| Prior Publication US 2007/0256313 A1, Nov. 08, 2007 | ||
| Int. Cl. G01D 5/347 (2006.01) | ||
| U.S. Cl. 33—706 [33/1 PT; 341/51] | 40 Claims |
| 1. Scale reading apparatus comprising:
a scale and readhead moveable relative to one another, said scale having scale markings arranged to form a first incremental
pattern having a first scale pitch and at least one scale marking arranged to form a second incremental pattern having a second
scale pitch, different to said first scale pitch;
a first detector to detect said first incremental scale pattern;
a second detector to detect said second incremental pattern;
wherein both first and second detectors are provided in the same readhead; and
the output of at least one of the first and second detectors may be selected to provide incremental position information.
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