초록 ▼

A safety device detects when a worker's hand enters a hazardous region between rollers of a kneading machine, and stops rotation of the rolls to prevent an accident. Each time the rollers are stopped, the orientation of photoelectric sensors is switched from the vicinity of the gap between the two r

A safety device detects when a worker's hand enters a hazardous region between rollers of a kneading machine, and stops rotation of the rolls to prevent an accident. Each time the rollers are stopped, the orientation of photoelectric sensors is switched from the vicinity of the gap between the two rollers to a test reflection member, and the quantity of received light is compared to a predetermined value, to prevent workers form starting work without knowing a fault or accident has happened. More specifically, a bar electrode of an electrostatic capacitance sensor is disposed above and near the gap between the two rollers, for detecting a physical quantity that is changed by entry of a worker's hand. When the electrostatic capacitance detected by the sensor exceeds a predetermined value, a judging circuit supplies a control signal to stop a driving unit that operates the kneading machine. Heat ray sensors or photoelectric sensors may be used as alternatives to electrostatic sensors. As an additional feature, case housing light projectors and photoelectric sensors are rotatably disposed above and near the gap between the two rollers, and a test reflector is disposed on the side of the case. When the rollers are stopped, a light receiving object switching circuit rotates the case and a test circuit tests the light receiving states of the photoelectric sensors.

대표청구항 ▼

[ What is claimed is:] [1.] A safety device for a kneading machine in which two laterally-juxtaposed rolls are disposed so that peripheral side faces of the rolls are close to each other and rotate in such a manner that movement of both of opposing peripheral side faces of the rolls are downward dir

[ What is claimed is:] [1.] A safety device for a kneading machine in which two laterally-juxtaposed rolls are disposed so that peripheral side faces of the rolls are close to each other and rotate in such a manner that movement of both of opposing peripheral side faces of the rolls are downward directed to thereby knead a rubber material, said safety device comprising:a sensor, selected from a group consisting of a heat ray sensor and a photoelectric sensor, for detecting a physical quantity that is changed by entry of a hand of a worker into a region in the vicinity of a gap between the two rolls, wherein said sensor is a reflection-type sensor for irradiating the region in the vicinity of the gap between the two rolls with only substantially linearly-polarized irradiated light, and for receiving only substantially linearly-polarized received light from the region that is different in polarization direction from the irradiated light;a reflection member adapted to be attached to a hand of a worker of the kneading machine, that reflects the irradiated light and changes the polarization direction of the irradiated light to the polarization of the received light;judging means for judging whether a change of the physical quantity detected by said sensor exceeds a predetermined range; andoperation stopping means for stopping operation of the kneading machine when said judging means judges that the change exceeds the predetermined range.