Patent GB-190706855-A (GB)
Title: Improvements in Governing Mechanism for Prime Movers.
Filed: 1907-03-21
Granted: 1908-03-21
Abstract: 6855. Warwick Machinery Co., [General Electric Co.]. March 21. Elastic-fluid turbines.- A governor transmitting- mechanism for elastic-fluid turbines and other prime movers comprises a constantly vibrating member, carrying pawls which engage a ratchet - wheel which rotates a valve-controlling shaft. A governorcontrolled shield renders the pawls inoperative except when the lond conditions require the actuation of the valves. A form of admission nozzle for elastic-fluid turbines is described. A lever 4, Figs. 1 and 2, is constantly oscillated by a connecting- rod 3 driven off the engine. The lever is loosely mounted upon the valve-actuating shaft 5, which is provided with valves 6, 6<a>, Fig. 2, each boss carrying a tooth 7, 7<a>, Fig. 5. These teeth engage notches 8, 8<a> in slides secured to the valve stems 10, 10<a>. The teeth are in staggered relationship, so that on the rotation of the shaft 5 the valves are opened or closed successively. When any valve is in either of the extreme positions, a further rotation of the shaft 5 merely causes the tooth to pass out of engagement with the corresponding notch in the slide. The lever 4 is fitted with arms 12, to which are hinged pawls 15, 16. Supplementary pawls or riders 17, 18 are secured to the spindles of the pawls 15, 16. The pawls 15, 16 engage a ratchet disk 20. A segmental shield 22 engages the riders 17, 18, and thereby moves the pawls 15, 16 to inoperative position. The position of the shield, and consequently the extent of movement given to the ratchet disk 20, is determined by a centrifugal governor. In the position shown in Fig. 1, the pawls 15, 16 are held out of engagement throughout their entire range of movement. If the shield is moved counterclockwise, the rider 17 drops off the end of the shield when the lever 4 moves to the right, thereby permitting the pawl 15 to come into operation. As the lever 4 starts back to the left, the pawl 15 engages the ratchet disk, thereby rotating the shaft 5 until the rider 17 encounters the edge of the shield and disengages the pawl from the ratchet tooth. Since the lever 4 is normally disconnected from the shaft 5, it is necessary to provide a means for locking the shaft in position when the pawls are out of engagement. An arm 23 is secured to the shaft and is provided with a segmental extension 24, which swings within a segmental casing 25. Spring-pressed balls or rollers 27 within the part 24 normally grip the casing 25. The bottom part of the ratchet-wheel is fitted with an arm, which pushes one or other of tha balls 27 up an inclined groove during the first part of the movement ; during the latter part of the movement, this arm carries the whole of the parts 24 with it, thereby rotating the arm 23 and shaft 5. The means for rotating the shield 22 comprise a connecting-rod 35, actuated by a governor, which rotates a lever 34 loosely mounted upon the shaft 5. An idle pinion 33 meshes with a spur wheel 31 rigidly attached to the ratchet disk and a rack 32 on the underside of the shield 22. Since the ratchet disk and spur-wheel 31 are normally stationary, the movement of the lever 34, to the upper end of which the pinion 33 is pivotally mounted, causes a movement of the shield in the same direction. A movement of the shield one way or the other causes one of the pawls 15, 16 to become operative, thereby causing the shaft 5 to be rotated in one direction or the other, and opening or closing one or more valves. To avoid the possibility of the rider over-travelling the shield by a very small amount, resulting in the pawl dropping into slight engagement with the ratchet disk and almost immediately being thrown out of engagement, a modification is described in which the rider 17 is provided with a spring blade 17<a>, Fig. 12, at the free end of which is an auxiliary rider 17<b>. As the pawl and riders move to the right, the pawl 15 cannot drop until the rider 17<b> clears the shield. On the return movement, the rider 17<b> passes underneath a lug on the shield, and the pawl is not thrown out of engagement until the rider 17 is thrown up by the shield. The invention is particularly applicable to governing turbines, in which case each valve 11, Fig. 11, controls a port 33, which preferably has a partition 39, thereby forming two discharge nozzles.