Patent GB-190208250-A (GB)
Title: Improvements in Speed Regulators
Inventor: BRIGG CHARLES HENRY
Filed: 1902-04-09
Granted: 1903-03-05
Abstract: 8250. Brigg, C. H. April 9. Transmitting- mechanism. - Relates more particularly to that class of transmitting-mechanism in which a movement of the governor throws reciprocating pawls or catches into engagement with a ratchetwheel connected, through gearing, with the valve-rod of the engine. Figs. 1 and 2 show side and end views, respectively, of a mechanism for heavy work, such as moving the spindle of the cut-off valve of a steam engine or governing a water-wheel. The pawls or catches 9 are carried by a disc 10 mounted loosely on a boss on the standard, and they are held clear of the ratchetwheel 11, which is fixed on the shaft 6, by the lateral arms of a T-shaped lever 12 pivoted at 13 to the disc 10. The usual arm 8 for reciprocating the pawls has a forked end which fits over a boss on the disc and is secured in position by bolts. By these means, the arm can be shifted from the right to the left of the shaft 6 according to requirements ; or it may be placed vertically and actuated from the engine by a horizontal connection. A ratchet-wheel 19, with pawls 16 carried by a disc 15 similar to the disc 10, is mounted on a countershaft 14 geared to the shaft 6 by spur-wheels 21. A link connects the arm of the disc 15 with the arm 8. The T-shaped levers 12, 17 are connected by links 12<11>, 17<11> to a shaft 22, which is rocked from one end of the lever 25 by a link 24. A spindle 27, fitted with springs, as shown, passes through the opposite end of the lever 25, and is attached to an arm 28 on the governor rod 4<1>. Any movement imparted to this rod by the governor is transmitted through the spindle 27 and lever 25 to the rocking-shaft 22, which moves the levers 12, 17 to the right or left, to allow one of each pair of pawls to engage alternately with the ratchet-wheels. The movement thus given to the shafts 6, 14, is transmitted from the shaft 6 to the valve-rod 4 by bevel gearing 5, 3. The rods 4, 4<1> are connected together by a nut 29 provided with right and left handed threads and made square to slide in the bevel-pinion 3. This pinion 3 is carried by a bracket bolted to an arm 3<11>, which is mounted loosely on a boss on the standard 1 and secured in position by bolts 7 passed through elongated holes, so as to allow it to be adjusted at any angle to suit the position of the valve-rod. To prevent further action of the pawls when the valve has been fully opened or the steam completely shut off, the shaft 22 is rocked to bring the levers 12, 17 to their normal positions, by one or other of the collars 37, 38 on a vertical spindle 39 engaging with the arm 36. The spindle 39 is raised or lowered by a nut formed by a wheel 40 gearing with a wheel 41 on the shaft 14. In order to hold the pawls clear of the ratchet-wheels when starting or stopping the engine, the shaft 22 is locked in its normal position by a spring bolt 42 engaging with a notch in the arm 12<111>. Immediately the required speed has been attained, the bolt is withdrawn and held out of the way by its bent end engaging the end of the bracket 43. The teeth of the ratchet-wheels are V-shaped to provide faces at right-angles to the centre line of the pawls, so that the latter may be disengaged at any part of the movement. In some cases, the levers 12, 17 are placed in an inverted position. Instead of providing the pawls with studs or rollers resting on the lateral arms of the levers 12, 17, they may be fitted with tails or fingers 30, Fig. 6, which rest on metal bands or shields 31 pivoted at 32. The free ends of these shields are inclined outwards, to form cams or inclined surfaces. A lever 33, mounted loosely on the axis of the ratchet-wheel, carries bowls or rollers which run on the undersides of the shields 31. When this lever is moved about its centre by the connections 34, 35 from the shaft 22, one or other of its arms is carried clear of the corresponding shield, so as to allow one of the pawls to actuate the. ratchet-wheel. For light work, the spur-wheels 21 are dispensed with and the ratchet-wheels are geared together. In this case, the pawls 9 are placed on the underside of the ratchet-wheel and provided with small counterbalance weights or springs. Fig. 5 shows an arrangement in which only one ratchet-wheel is used.