Patent GB-198664-A (GB)
Title: Improvements relating to balancing machines
IPC: G01M1/04
Filed: 1923-05-22
Abstract: 198,664. Metropolitan - Vickers Electrical Co., Ltd., (Assignees of Kasley, A. T.). May 31, 1022, [Convention date]. Testing balance of rotary apparatus.-A machine for determining the amount of static and dynamic unbalance of a body comprises means for supporting and rotating the body in the machine and a source of energy by which forces regulatable in time and magnitude may be imposed on the body or its supporting means to neutralize vibrations due to unbalance of the body. Each' end of the rotary body 13, Figs. 1 and 2, is supported in the bearings 11 of a pendulum 10, which is connected to a frame 14, adjustable upon a bedplate 16, by a flexible beam 15 and also by springs 18 to magnify the vibrations when a condition of resonance is reached, each pendulum being associated with a vibration indicator 20. A motor 21 driving the rotor 13, also drives through a counter-shaft 23 an eccentric 24, which oscillates a lever 26 about an adjustable fulcrum pin 27 so as to stretch and compress alternately a spring 28 connected to the pendulum 10. The rotation of the body 13 sets up forces which swing the pendulum, and at the same time the shaft 23 operates the spring 28; the lead or lag of the eccentric 24 being next adjusted so that the tensile and compressive forces of the spring 28 act exactly in phase with the forces set up by the rotor 13. This eccentric 24 is adjusted by means of a, yoke 32, which moves a sleeve 29 splined to the shaft 23 and having a steep-pitched screw-thread connection 31 with the eccentric, the lead or lag of which is shown by the indicator 34. To counteract completely the forces set up by the rotor, the force applied by the spring 28, as well as its moment of application, must be adjusted, and this is done. 'by loosening the clamping screw 42, Fig. 1, and adjusting the fulcrum pin 27 carried by the arm 40, the force applied by the spring being indicated on the scale 44. In operation, the pendulum at one end of the rotor 13 is held rigid by tightening the screws 19, Fig. 1, the position and magnitude of the unbalanced forces at the other, or freely oscillating, pendulum being determined. The reverse operation is then. performed by loosening the first pendulum and holding the second one rigid. In a modification,. Fig. 4, the springs 28 of Fig. 1 are replaced by pressure-fluid devices 49 supplied from a source, 48 through throttle valves 55, 60 and piston-valve devices 50, 51 operated by eccentrics 68, 69 from the motor 21. The eccentrics are arranged at 90‹' phase difference so that the inlet port 52 communicates with the outlets 61, 62 at intervals of- 180‹ of rotation cf the rotor 13; and the inlet 57 communicates with outlets 64, 65 at intervals of 180‹ also, but 90‹ later than in the case. of ports 52, 61, 62. Each device 49 comprises tandem cylinders 70, 71 having a common piston-rod 74 connected by a pin 75 to the pendulum 10, and a four-way valve 80 for connecting either of the inlet ports' 76, 77 with either of the pipes 78, 79 leading to the; ports 61, 62 and similarly with cylinder 71, four-way valve 85 and pipes 83, 84. The pipe-lines 78,79,83,84 may be connected with either of the devices 49 by means of valves 87 - - 94, and pressure gauges 95, 96 are used. The operation is the same as in the case of the construction shown in Figs. 1 and 2, the fluid pressure) acting through the piston-rod 74, in place of the force of the spring 28, Fig. 1. In using the vibration indicator 20 for ascertaining the degrees of unbalance before the force of spring 28 &c. is imposed, the vibrations may be damped by means of a friction plate. 151, Fig. 22, attached to the pendulum and rubbing against a stationary spring- pressed plate 152. In a further modification, Fig. 8, the pressure-fluid feature of Fig. 4 is combined with the phase-changing feature shown in Fig. 2, each pendulum 10 being connected by a pin 103 to a piston 102 in a cylinder 101, the two ends of which are supplied alternartely with pressure-fluid by means of piston-valve mechanism 112, ports 110, and a throttle valve 107 from a source 105. The piston valve is actuated by an eccentric 115, the lead of which is adjusted by a sleeve 29 and screw thread 31 as in Fig. 2. In further modifications, (a) a single-acting; or (b) a double-acting pressure-fluid expansible-cylinder device is provided with a rotary valve 125, Fig. 10, which may be adjusted by means of its rotating part 130, the screw-thread 31, and the axially movable sleeve 29, so that. the time of application of the pressurefluid impulses may be varied. In another construction; shown in Fig. 18, the rotary valve controls the admission of pressure-fluid alternately to the two sides of a diaphragm 163 directly connected by a, rod 164 to the pendulum 10.