Screw clamp

A screw clamp, comprising:

• a clamping unit;
• a slide rail;
• two clamping arms between which a workpiece is clampable, wherein in a clamping process at least one of said clamping arms is adjustable along an axial adjustment path by means of said clamping unit which is manually rotatable about an axis of rotation, by building up a clamping force acting against the workpiece;
• said clamping unit containing a threaded drive having a radially outer adjusting sleeve with at least one internal thread and radially inner threaded stroke elements including a first threaded stroke element and a second threaded stroke element, at least one of said radially inner threaded stroke elements having an external thread being in threaded engagement with said at least one internal thread of said radially outer adjusting sleeve and is bringable into force-transmitting connection with said clamping arms, and in that in the clamping process said radially outer adjusting sleeve is rotationally actuated, whereby at least one of said radially inner threaded stroke elements together with a clamping arm of said clamping arms connected thereto is displaced against the workpiece along the axial adjustment path, at least one of said radially inner threaded stroke elements having a recess formed therein;
• the force-transmitting connection between said clamping arm being an adjustable clamping arm and said at least one radially inner threaded stroke element is provided by said slide rail connected to said adjustable clamping arm, in that said slide rail, in an unclamped state, is guidable in a loose fit in a smoothly movable manner through said recess in said at least one radially inner threaded stroke element;
• said slide rail has, as an anti-slip device, a corrugation which, in a case of an oblique position of said slide rail, cants with a counter-contour of said recess formed in said at least one radially inner threaded stroke element;
• and
• said two clamping arms are each adjustable along the axial adjustment path upon a rotary actuation of said clamping unit, and that said at least one internal thread of said radially outer adjusting sleeve includes a first internal thread and an axially adjacent, opposite second internal thread, which are each in threaded engagement with said first threaded stroke element and with said second threaded stroke element.