A short circuit arc welding system is disclosed. The first transmission unit has first and second intermediate transmitting paths through which a rotary motion of the input rotary member is transmittable to the second transmission unit such that a speed of the rotary motion transmitted through the second intermediate transmitting path is lower than a speed of the rotary motion transmitted through the first intermediate transmitting path. A support member is disposed across at least a portion of the well region such that the ends of the arms extend beyond the support member. The use of reflective elements can reduce the depth of the imaging system, allowing for more compact designs. The resilient element elastically resists the block.