GB976104A - Improved control system for power systems - Google Patents

Abstract

976,104. Reverse gear control. T. HINDMARCH. Feb. 8, 1963 [Feb. 21, 1962], No. 6801/62. Heading F2D. [Also in Division G1] In a reverse gear control for a ship, rail-car or rolling mill wherein hydraulically operated forward and reverse clutches C2, C1 are controlled by a selector valve MCV in response to signals from a manual control CH which also controls engine speed, switches f, g, h, i controlled by input and output speed responsive devices SS1, SS2 prevents establishment of a ratio if the gear input or output speed exceeds a predetermined value and triple switches a, b, c; j, k, I respectively responsive to engagement of the clutches C1, C2 prevent engagement of one clutch while the other is engaged and prevent increase of engine speed until one of the clutches is fully engaged. Ratio shift may be facilitated by providing a brake B on the output shaft which brake is engaged when the selector valve MCV is in its neutral position, or by providing switches d, e which hold the clutch for the previous ratio engaged, after the manual control has been moved to the neutral position, until the output speed falls below a predetermined value. Movement of the manual control CH from the netrual position shown to the ahead position closes a switch n and completes a circuit through switches h, f, a to a solenoid valve SV1 which supplies pressure liquid to a servomoter VO1 that operates the selector control valve MCV. When the forward clutch C2 is fully engaged a pressure sensitive element PS2 changes switches j, k, l. The switch j completes a holding circuit to the solenoid valve SV1 which bypasses the switches f, h so that when the input and output speeds increase and the switches f, h open the solenoid valve SV1 remains energized. The opened switch k ensures that the reverse solenoid valve SV2 cannot be energized whilst the forward clutch C2 is engaged and the switch h completes a circuit in the engine speed control SC that permits increase of engine speed. On movement of the manual control CH from the ahead position to the astern position the energization of reverse solenoid valve SV2 and engagement of the reverse clutch C1 is delayed until the forward clutch C2 is disengaged and the switch K is closed and until the input and output speeds fall below a predetermined speed to close switches g, i. An engine speed follow-up control, Fig. 2 (not shown) is unbalanced and returns engine speed to idling when both switches c, h are open during ratio shift. An emergency control which overrides the delay mechanism may be provided.