Abstract: A platform for use in loading and supporting a gas cylinder onto a movable welder undercarriage which platform comprises a lower cylinder support pate with a rear end, a front end and a normal level cylinder supporting position; means for mounting the platform on the rear of the undercarriage to pivot about a transverse axis in a first pivot direction to a cylinder loading position with the rear end of the support plate tilted downward against the floor and in a second pivot direction with the support plate in the cylinder support position, where the weight of said cylinder is one the side of the pivot axis toward the front end of the support plate; and, stop means for preventing rotation of the platform abut the pivot axis in the second direction beyond the normal position of the support plate of the platform.