Pre-tightening force adjusting device for measuring thrust of high-thrust liquid rocket engine

A main body of a pretightening force adjusting device used in a thrust measuring system of a high-thrust liquid rocket engine at least comprises a base fixed on a movable frame ring, a top seat fixed on a fixed frame of a thrust frame, a plate spring playing a force arm transmission role and a connecting structure. Wherein a force arm is formed through a plate spring to reduce the acting force applied by an operator, and a joint ball bearing is used in the connecting mechanism for aligning the applied acting force. During loading, the positioning seat is adjusted through the torque wrench, and the starting frame is lifted through deformation of the plate spring, so that the working sensor is pressed, and the loading of the pretightening force is realized. The device has the advantages that the applied acting force can be ensured to be consistent with the thrust axis, and the measurement precision of the thrust is not influenced; the device is simple in structure and convenient to operate, can load uniformly o