Patent GB-181004-A (GB)
Title: Improvements in and relating to devices for dynamically determining the position of the centre of gravity of rapidly rotating parts of machinery
IPC: G01M1/04
Filed: 1922-05-29
Abstract: 181,004. Krupp Akt.-Ges. F. May 31; 1921, [Convention date]. Testing balance of rotary apparatus.-Comprises a device for determining dynamically the position of the centre of gravity of a rotary machine part and consists in providing a rotatable. frame upon which the machine part is mounted so as to swing about a fixed axis relatively to the frame and to rotate about its central axis, which coincides with the axis of rotation of the frame when the part is in the mid position of its swinging movement. In the form shown in Figs. 1 and 2, the hollow stem b<3> of a stirrup frame B is mounted to rotate in a support A. A carrier C is mounted by knife-edges c<1>, c<2> on the ends of the stirrup legs B<1>, B<2>, and is provided with a pivot D to receive the part E to be tested. The axis of the pivot D lies in the mid plane of the carrier C passing through the axis of the knife-edges and is at right-angles to this axis. Two pointers c<3> attached to the carrier are provided in this plane as shown, and two other pointers c<4> in a plane passing through the axis of the pivot D and at right-angles to the mid plane mentioned above. The frame B is provided with a pointer b<6> moving over a scale c<5> on the carrier C. Two centring- screws c<6>, c<7> prevent movement of the carrier in the direction of the knife-edge axis. On the leg B<1> is fixed a channel-shaped member b<9>, one arm of which carries a set-screw F, the movement of which is indicated on a scale b<10>. The set-screw is attached to one end of a spring G the other end of which is fixed to the carrier C. A similar spring G<1> is interposed between the carrier C and the other arm of the member b<9>. Within the stem b<3> is a shaft H connected by a pin and slot with a hollow shaft K, a spring J being arranged between collars on the shafts as shown. The shaft K is surrounded by a sleeve K<1> having a helical slot k<2> engaging a pin b<11> on the stem b<3>. The shaft H may be slid longitudinally by means of the lever L, L<1> and may be turned relatively to the stem b<3> by moving the lever N, N<1> to slide the sleeve K<1>; the shaft H at the upper end is provided with a cup h<1> which co-operates with a cone d<1> on the end of the pivot D to form a friction clutch. In use, with the parts arranged as shown in Fig. 1 with the clutch d<1>, h' fully engaged, the stem b<3> is rotated by hand through the bevel gear a<3>, b<12>. When a suitable speed is attained, the shaft H is moved down so that the point only of the cone d<1> is in the cup. The carrier C then swings about the knife-edges and the position of the index b<6> is noted. By manipulation of the levers L, L<1>, N, N<1> and further rotation a position is obtained in which the index b<6> reads zero. The part E is now in static balance. The operation is now stopped and marks scribed on the body E at the pointers c<3>. The part E is then rotated through 90‹ so that these marks lie opposite the pointers c<4>. The device is again rotated and the deflection of the pointer b<6> noted. The set-screw F is then moved until this reading is zero. The reading of the .pointer f<1> on the scale b<10> then gives the balancing moment. Several modifications are described in one of which weights are substituted for the springs G, G<1>, while others are adapted to testing machine parts having a journal at each end.