of the mating collars 24 26 are received in the grooves 103 of the link elements 98 next the elongated rod 102 is pivoted about the pin 112 that connects it to a link element 98 in a direction toward the link element 98 to which the toggle means 104 are connected this pivoting of the elongated rod 102 causes the toggle means 104 to pivot about the pin 110 connecting it to a link element 98 in the same direction as the elongated rod 102 the pivoting of both the elongated rod 102 and the toggle means 104 causes the overall circumferential length of the linked members 98 100 102 104 to be reduced exerting compression on the outer circumference of the mating collars 24 26 the compression exerted on the mating collars 24 26 is redirected by the beveled surfaces 25 27 in cooperation with the beveled portions 105 of the link element groove 103 such that the mating collars 24 26 are pressed against each other in sealing contact the toggle means 104 are pivoted to a position where a hole 125 in each plate 108 is aligned with a hole 107 in each plate 99 of the link element 98 a shear pin 109 is inserted through the holes 125 107 in order to lock the toggle means 104 to the link element 98 in this position the coupling device 10 is locked and the conduit ends 12 14 are joined to regulate fluid flow under normal operating conditions the ball valves 20 22 are positioned as shown in fig s 7 8 fig7 shows both ball valves 20 22 in the open position to allow fluid flow fig8 shows.