Patent GB-557701-A (GB)
Title: Improvements in or relating to governors
IPC: G05D13/00
Filed: 1942-05-22
Abstract: 557,701. Speed governors. KALIN, A. Ma 22, 1942, No. 7017. Convention date, June 2, 194 [Class 135] A normally isochronous speed governor particularly adapted for controlling Diesel engines is provided with means to give a variable speed droop and with means operating as a function of change in the speed setting to adjust the amount of speed droop of the prime mover under predetermined load so that the droop is always the same percentage of normal speed under no load over the entire range of speed settings of the governor. In the arrangement shown in Figs. 1, 2 and 4 the servomotor actuating the engine regulator, the governor actuated control valve, the hydraulic follow-up, the motive fluid supply pump, the governor drive and the power means for adjusting the governor spring are substantially the same as those described in Specification 550,568. The governor loading spring 51 is adjusted by a lever 80 extending diagonally across the speeder case bifurcated at one end 97 to engage the tubular piston rod 88 of the adjusting power piston 87 and at the other end is coupled to the mechanism for giving the adjustable speed droop. This comprises a shaft 120 mounted on pivots 121 and provided with a toothed pinion 128 engaging a rack 129 formed on a rod 130 held by a spring 131 in engagement with the main power piston 22. An eccentric ring 123 is adjustably mounted on eccentric part 122 of the shaft and is secured in its adjusted position by a lock-nut 125. An eccentric strap 135 is mounted on the ring between a flange 134 and the pinion 128 and is held against rotation by a fork engaging a fixed pin 139. A follower 140 is held against the strap 135 by a blade spring 142 and is formed with a bifurcated part variably coupled to the bifurcated end of the lever 80 by a pin 145. This pin is carried by a block 153 adjustably secured to a link 154 coupled to a bell crank lever 150. The lever is adjustably coupled by a pin and slot 157 and link 152 to the lever 80 so that as this lever is moved to reduce the tension of the spring 51 the speed droop is correspondingly reduced. The percentage speed droop is varied by turning the eccentric ring 123 on the eccentric 122 and the ring may be turned into a position in which the droop is zero rendering the governor isochronous. In a modified arrangement shown in Fig. 6 the adjustable loading spring abutment 83 is carried by a lever 165 pivoted to a lever 163 on a shaft 160 provided with a toothed segment 161 engaging a pinion 162 adapted to be rotated by a Selsyn motor. The lever 165 has an arm 175 engaged by an arm 174 on a shaft 168 concentric with the shaft 160 and provided with an arm 169 slidably engaging a slot 173 in a link 172 moved by the main power piston 22. The link 172 is adjustably coupled by a link 171 to an arm 170 on the shaft 160 so that as this shaft is rotated to vary the governor loading the leverage of the arm is varied. If extremely accurate recalibration is required a geometrical cam mechanism or its equivalent is used in place of the lever and link connection between the arm 170 and link 172. The Specification also describes other detail modifications of the governor described in Specification 550,568. To enable the rotation of the speed governor to rotate the valve member 20 the member 55 is made of cobalt steel and highly magnetized with opposite poles spaced 180 degrees apart and the ball arm fingers are offset on opposite sides of the axis of rotation. To enable extreme adjustment of the loading spring adjustment to lift the control valve positively and stop the engine an arm 180 on the adjusting shaft is coupled by a chain 181 and swivel connection 182 with a hollow nut 183 secured to the upper end of the valve spindle. In another form the chain is replaced by a rod and lost-motion device. To prevent too rapid movement of the main power piston in the power increasing direction at critical ranges of operation a device is fitted which permits rapid movement through an adjustable distant followed by a damped movement. The space 191 above the reduced part 39 of the power piston is supplied with oil from the sump through an upwardly closing non-return valve 195. Rapid upward movement of the piston forces oil through a passage 194 to a chamber 193 where it raises a piston 199 against a light spring into engagement with an adjustable stop 202 and afterwards escapes to the sump through an adjustably throttled orifice 203. Slow movements are insufficient to close the non-return valve.