1. The dynamic stability of loading value being good, and with the great ability to absorb vibration, the pendulum arm can be suited to the high speed running of spinning frame and wouldn't produce pressure failing after a long period of time. It has the features of steady and correct loading, less loading difference between spindles, long service life, compact construction, and convenient maintenance.

2. Loading, unloading, and semi-unloading of the pendulum arms of a whole spinning frame xcan be obtained by adjusting the pressure in a gas-bag; and hence the worker's labour can be greatly lightened, and the end-breaking rate at restarting the machine can be effectively reduced.

3. When spinning fibre material in fifferent staple length, and the front, rear zone gauge of the pendulum arm need rugulating, the pressure ratio between the three top rollers can still be fixed roughly, but the concrete pressure value can infinitely adjusted by changing the pressure intensity in a gas-bag.

4. The central raised arc on the top of holding part of each top roller can well guaranteethe pressure on the left and right spindles to be equal.

5. The front and middle loading device are formed an integral whole and then installed in a rear distributing rod, which can strictly guarantee the parallelism between the rollers in main drafting zone.

6. The locking device of four-bar linkage is adoopted with its locking being reliable,and its loading or unloading being easy and light.After unloading, the pendulum frame can be raised to the rigid setting angleof 60, which is convenient for worker to clean and maintain the machine.