A belt-like hip-girdling pelvic sling device for maintaining a desired amount of tension surrounding a person's hips and pelvis to securely support and stabilize a fractured pelvis, including a force-controlled buckle that automatically latches to control the tension and that includes a releasable latching mechanism. The latching mechanism maintains engagement of the buckle with a strap at the required position of the strap with respect to the buckle. The latching mechanism includes a movable member of the buckle that is moved to and latched in a position in which the buckle engages the strap, once a desired amount of tension is reached, limiting and maintaining the required tension.
