Abstract: A claw clamp has a first half and a second half with a claw formed at one end of each half. Substantially opposite the claw end of the first half a first hole having a larger diameter portion and a smaller diameter portion is formed. Between the first hole and the claw a second hole is formed. A first rod having threads on one end and an enlarged end opposite the threads passes through the first hole and retains a spring inside the first half. A second rod having threads on one end and a knob or hex head opposite the threads passes through the second hole. The threads engage corresponding threads cut into the bottom half. The spring biases the two halves together while the knob or hex head allows the clamp to be tightened.

Abstract: A claw clamp, such as that used in conjunction with an ISO flange is illustrated. The clamp is able to hold itself on a flange assembly prior to tightening. This is accomplished by a mechanism that pressures the two halves of the clamp together prior to tightening so that the clamp can be positioned on a flange assembly and will hold itself there without intervention until tightening.