Abstract: The drive is controlled such that reduced pressure is applied during a forward motion phase and venting flow from the drive is used as dynamic control pressure to hold off application of full driving pressure until, through physical impediment, piston movement stops. This way rebounding is prevented and strong holding pressure (e.g. on welding electrodes) is made available after a low power motion phase.

Abstract: Welding tongs for dot or spot welding having two arms which are disposed without crossing relationship and carrying weld electrodes respectively on one end. The arms are made of flat, spaced bars, and a substantially flat spacing member made of an elastic or resilient material, spaces the two arms from each other thereby interconnecting the tong arms in a range of pivot motion of the arms. An E-shaped mounting member limits lateral deflection of the tong arms and holds the spacing member. A hydraulic drive is connected to the other ends of the tong arms for obtaining the pivot motion of the arms in relation to each other, through tensioning and upsetting or compression of the spacing member.