DEVICE FOR DETECTING AMOUNT OF OIL IN SEWING MACHINE

PROBLEM TO BE SOLVED: To improve convenience.SOLUTION: A device for detecting the amount of oil in a sewing machine comprises: a light-emitting element 51 for emitting detection light for detecting the amount of lubrication oil in an oil tank 4; a first light-receiving element 52 arranged therebelow; a second light-receiving element 53 arranged further therebelow; and a prism 54 for guiding the detection light to the first or second light-receiving element according to the amount of the lubrication oil in the oil tank. The prism comprises: a first reflection surface 541 for reflecting the detection light from the light-emitting element downward; and a second reflection surface 542 for reflecting the detection light reflected by the first reflection surface toward the first light-receiving element. The first and second reflection surfaces are provided vertically side by side in such an arrangement as to be in contact with the lubrication oil in the oil tank. The prism is formed of a material having such a refractive index as to transmit the detection light when reflection positions P1 and P2 of the detection light on the first and second reflection surfaces, respectively, are below the liquid level of the lubrication oil. The second light-receiving element is provided on a path along which the detection light reflected by the first reflection surface 541 is transmitted through the second reflection surface of the prism.SELECTED DRAWING: Figure 2 【課題】利便性の向上を図る。【解決手段】オイルタンク４内の潤滑油の油量の検出光を出射する発光素子５１と、その下方に配置された第一の受光素子５２と、さらにその下方に配置された第二の受光素子５３と、オイルタンク内の潤滑油の油量に応じて第一又は第二の受光素子に検出光を導くプリズム５４とを備え、プリズムは、発光素子からの検出光を下方に反射する第一の反射面５４１と、当該第一の反射面に反射した検出光を第一の受光素子に向けて反射する第二の反射面５４２とを備え、第一及び第二の反射面が、オイルタンク内の潤滑油に接触する配置で上下に並んで設けられ、プリズムは、第一及び第二の反射面のそれぞれの検出光の反射位置Ｐ１，Ｐ２が潤滑油の液面下となる場合に検出光を透過する屈折率のものからなり、第二の受光素子は、第一の反射面５４１に反射した検出光がプリズムの第二の反射面を透過する進路上に設けられている。【選択図】図２