From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Description of a thrust element indicator using a diaphragm, carbon pile rheostats, and a Wheatstone bridge circuit.
| Identifier | ExFiles\Box 165\4\ img047 | |
| Date | 28th March 1928 guessed | |
| -2- with the bore 20 in the frame 16. The lower end of the bore 20 is sealed by means of a diaphragm 26 which may be secured to the frame 16 by welding or brazing. The diaphragm may be of the type illustrated or of the well known Sylphon bellows type with corrugated sidewall. The diaphragm 26 is provided with a central aperture 28, to the bounding edges of which is secured the rigid thrust element for operating the indicator. This element is in the form of a tube 30, shown as secured to the diaphragm by forming the lower end with a channel 32 into which edges of the diaphragm are fitted, whereupon the walls of the channel are clinched about it. Obviously the connection may be accomplished by welding or brazing if preferred, the only requirement being that the connection shall be secure and gas tight. The upper end of the tube 30 is threaded and is rigidly secured to the arm 24 by means of clamping nuts 33, as shown. It is now obvious that with this arrangement movement of the diaphragm 26 is transmitted by the tubular thrust member 30 to the rigid arm 24 and this effects operation of the indicating mechanism which is substantially the same as that shown in my prior application and now to be briefly described. On opposite sides of the rigid arm 24 are arranged carbon pile rheostats 34 and 36. The rheostats consist of carbon discs clamped between end plates. The end plates remote from the rigid arm provided with conical recesses 38 to receive the conical ends of adjustable screws 40 threaded in the frame 16. Lock nuts 42 are provided to hold the screws in adjusted position. The adjacent end plates are provided with integral conical studs 44 which engage in recesses formed in opposite sides of the rigid arm 24. The remote end plates are insulated from the frame 16 by means of interposed insulating disks 46. The recess 22 is enclosed by means of cover plates 48 and 50. Upon the cover plate 48 are mounted three terminals 52, 54 and 56. Terminals 52 and 56 are insulated from the frame 16 but electrically connected to opposite ends of the rheostats 34 and 36, respectively as shown. Terminal 54 is in electrical connection with frame 16. Conductors 58 and 60 lead from terminals 52 and 56 respectively to the ends of fixed resistances 62 and 64 respectively. Conductor 66 leads from the terminal 54 through the oscillograph element 68 to conductor 70 connecting the adjacent ends of the fixed resistances. Rheostat 34, terminal 52 and conductor 58 constitute one leg of a Wheatstone bridge. Rheostat 36, terminal 56 and conductor 60 constitute another leg of a Wheatstone bridge in series with the first leg. The other legs of the bridge are constituted by the fixed resistances 62 and 64. The bridging circuit consists | ||