A locking clamp device is provided with first and second clamping members. The first clamping member includes a base member with a first clamping surface and a locking member movable with respect to the base member between a securing position and a releasing position. The second clamping member is slidably engaged with the first clamping member and selectively movable to a plurality of clamping positions. The second clamping member includes a second clamping surface opposite the first clamping surface. The lockout device further includes a means for preventing movement of the locking member from the securing position to the releasing position. The locking member is configured to secure the second clamping member in one of the plurality of clamping positions when the locking member is in the securing position.