BigPatents India

An oil-deficiency indicator for sewing machines which comprise an oil tank (16) for supply of at least one lubricating point is characterized by an immersion body (60) which is insertable from above into the oil tank (16) and has a bottom of transparent material; at least one reflection surface (84, 86) on the transparent bottom; a light source (78) above the reflection surface which emits a light beam on to the reflection surface (84, 86); and a light receiver (80) in the beam pat of the light beam of the light source (78) which is reflected byte reflection surface, releasing a switching pulse by reception of light. (FIG.2)