Encoder having a slidably engaged floating aperture piece

An encoder, comprising:

• a housing;
• a light source coupled to the housing;
• a light sensor coupled to the housing and positioned to receive a light beam from the light source;
• a wheel having opaque and transmissive sections which may be positioned to pass through the light beam before it reaches the light sensor;
• and
• a floating aperture piece, which defines at least one aperture, wherein:
• the aperture is positioned so that the light beam must pass through it before reaching the light sensor;
• and
• the floating aperture piece slidably engages the housing while allowing a loose tolerance between a position of the wheel and a position of the housing, thereby substantially eliminating a positioning error between the aperture and the wheel;
• wherein the spring member is a flexible protrusion integral with the housing.

An encoder, comprising:

• a housing;
• a light source coupled to the housing;
• a light sensor coupled to the housing and positioned to receive a light beam from the light source;
• a wheel having opaque and transmissive sections which may be positioned to pass through the light beam before it reaches the light sensor;
• and
• a floating aperture piece, which defines at least one aperture, wherein:
• the aperture is positioned so that the light beam must pass through it before reaching the light sensor;
• and
• the floating aperture piece slidably engages the housing while allowing a loose tolerance between a position of the wheel and a position of the housing, thereby substantially eliminating a positioning error between the aperture and the wheel;
• wherein the notch has an arcuate portion.

An encoder, comprising:

• a housing;
• a light source coupled to the housing;
• a light sensor coupled to the housing and positioned to receive a light beam from the light source;
• a wheel having opaque and transmissive sections which may be positioned to pass through the light beam before it reaches the light sensor;
• and
• a floating aperture piece, which defines at least one aperture, wherein:
• the aperture is positioned so that the light beam must pass through it before reaching the light sensor;
• and
• the floating aperture piece slidably engages the housing while allowing a loose tolerance between a position of the wheel and a position of the housing, thereby substantially eliminating a positioning error between the aperture and the wheel;
• wherein the notch has a linear portion.