US 9,810,525 B2
Bolt sensor
Takayori Hashimoto, Fujisawa (JP); and Takuya Kitajima, Fukuroi (JP)
Assigned to MINEBEA CO., LTD., Kitasaku-gun (JP)
Filed by MINEBEA CO., LTD., Kitasaku-gun, Nagano (JP)
Filed on Jun. 16, 2016, as Appl. No. 15/184,285.
Claims priority of application No. 2015-131332 (JP), filed on Jun. 30, 2015.
Prior Publication US 2017/0003118 A1, Jan. 5, 2017
Int. Cl. G01B 11/16 (2006.01); G01L 5/24 (2006.01); G01M 5/00 (2006.01)
CPC G01B 11/16 (2013.01) [G01L 5/243 (2013.01); G01M 5/0041 (2013.01); G01M 5/0091 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A bolt sensor configured to detect a fastened state of a bolt, comprising:
a sensor body including a through hole into which a shaft of the bolt is to be inserted;
a light guide extending along an outer periphery of the sensor body; and
a light source configured to emit light to the light guide based on output of the sensor body, wherein
the light guide includes a light guide plate having an incident surface through which the light from the light source enters into the light guide plate and an emission surface from which the light entered into the light guide plate through the incident surface is emitted, and
an opposing surface, of the light guide plate, on an opposite side of the emission surface has a plurality of concaves which reflect the light entered into the light guide plate through the incident surface toward the emission surface.