Why does the x ray hand switch design two steps for control x ray exposure?

The two steps x ray exposure hand switch is mainly used on mobile x ray, portable x ray and bedside x ray. When operation the x ray machine, the doctor or operator need to start on the exposure button. Sometimes, the doctor may help the patient to keep the proper position or take on patient files. If the hand switch designed one button, if the doctor not care, it may touch the button and make exposure.

For example, if the doctor prepare to make exposure and find the patient position not well, he may put the hand switch in his pocket and help the patient, but when he bows the hand switch button may tactile during the pocket rub.

Therefore, designed two buttons, when push button one, the x ray machine enter into exposure ready status, that remind the doctor the x ray machine can exposure by next instruction. Even if the hand switch is put in the pocket, the rub only can tactile the step one button, it can not tactile x ray exposure.

This design also give the doctor another option he could give up exposure when he think the status not proper.