"he conventional JSTD20 two-hand device utilizes a welded steel housing. Two operating push buttons are protected by over hand flanges. Between these push buttons there is space for a emergency push button and two extra controls or indication lamps. Below each of the operating push buttons is one normally open and one normally closed contact. To start and run the machine both push buttons must be activated within 0.5 seconds. If one or both push buttons are released a stop signal is given to the machine, and all contacts must return to their deactivated positions before a new start is allowed.","The design is robust and can withstand harsh environments and long use. The push buttons and contact blocks are easy to assemble for quick and easy installation. The device can be mounted directly on the machine, on the Jokab Safety fencing system or on the JSTS30 floor mount. For use with movable Two hand devices the JSTS31 floor mount, which is provided with a distance ring to fulfill the requirements of EN 574, is recommended. The JSTD20 is available with or without emergency stop push button.","Why use a two-hand device?","A two hand device can be used when it is necessary to ensure that the operator is outside and must be prevented from reaching into the hazardous area. If the operator decides, after the start signal has been given to the machine, to make an ’after grasp’ i.e. try to adjust the part that has been placed inside the machine, then a dual stop signal is given to the machine. The new JSTD20 is equipped with a new type of large over hand flange according to EN 574.","These prevent unintended activation by a knee or elbow. A two-hand device only protects the operator using it. Large machines operated by several operators can be equipped with one control for each operator. To calculate the correct safety distance, which depends on the machine’s stopping time including the relay’s reaction time, the use of the Jokab Safety SMART Stop Time Monitor is recommended.","Highest Safety Level","Correct connection to a JSBR4 Jokab Safety safety relay ensures the highest level of safety with dual and supervised safety function and requires input activation of both operating push buttons within 0.5 seconds (two hand device type III C according to EN 574 and category 4 according to EN 954-1\/EN ISO 13849-1). If the emergency push button is installed it should be provided with two normally closed contacts and be connected to a separate safety relay, e.g. from the RT series or Pluto."
