causes the restraining member to move to a non restraining orientation thereby in turn causing the locking member to move so that its engaging surfaces engage the engaging surfaces of the frame clamping the band an alarm is triggered to notify a practitioner that the predetermined level of tension has been achieved and that the restraining member has thus moved to the non restraining orientation application_number US 201213476970 A description referring now more particularly to the drawings there is shown in fig1 and 1 a a common buckle 1 which includes a lock bar 2 about which a strap having strap tails 4 and 5 extends a surface 6 of the lock bar 2 moves away from a surface 8 on the buckle 1 when the strap tail 5 is tensioned as the strap tail 5 is tensioned the strap tail 4 is pulled into an interface between surfaces 6 and 8 when the strap tail 5 is released the strap tail 4 holds the dominant tension which pulls the lock bar 2 so that the strap is pinched between the surfaces 6 and 8 this is the locked position of the buckle 1 lock bar 2 is held in position by tabs on both of it ends which ride in a slot 10 which is cut out of a frame 12 the slot 10 is critical in the operation because it holds the surface 6 on the lock bar 2 so that it correctly pinches the strap up against the surface 8 the variability of the tension in strap tails 4 and 5 causes.