Patent GB-421204-A (GB)
Title: Automatic disengaging and engaging device for a clutch, more particularly between the motor and the driving gear of power driven vehicles
IPC: F16D23/10
Filed: 1933-08-14
Abstract: 421,204. Operating clutches. MAYBACH-MOTORENBAU GES., Friedrichshafenon-Bodensee, Germany. Aug. 14, 1933, No. 22662. Convention date, Sept. 24, 1932. [Class 80 (ii)] The clutch of a motor-vehicle is automatically disengaged at a predetermined low speed of the engine, is partially engaged when the engine speed is increased, the engaging pressure increasing with the engine speed, and is completely engaged, irrespective of the speed, only upon the occurence of synchronism of the clutch parts. A pump 11 driven from the gear shaft 14 delivers fluid from a reservoir 18 into a chamber 19, while a pump 7 driven from the engine shaft 10 delivers from the chamber 19 into a chamber 20. The chamber 19 is in communication with the reservoir 18 through a passage fitted with a spring- loaded suction valve 6, and an outlet 29 from the chamber 20 is controlled by an adjustable screw 30. A spring-loaded piston valve 31 is controlled by the pressure in the chamber 19, while a spring-loaded piston valve 21 and a piston 23 are controlled by the pressure in the chamber 20, a spring 26 being interposed between the piston 23 and a second piston 27 which is loaded by a spring 28 adjustable by a screw 38. With the engine idling, the screw 30 is so adjusted that the pressure in chamber 20 is insufficient to lift the members 21 and 23. Thus the suction in the engine intake manifold 1 is effective through conduits 2, 4, 41, 45, to move a spring-loaded valve 40 to the right so as to bring a conduit 44 branching from the conduit 41 into communication with a conduit 49 branching from a conduit 51 which leads to a servomotor 52, the piston 53 of which is connected to the clutch operating lever 57. Thus the full suction in the manifold 1 is communicated to the servo 52 which is therefore effective to disengage the clutch against the action of the clutch spring 17. The upper edge of the piston 27 controls a conduit 3 branching from the conduit 2, while the lower edge controls a conduit 48 branching from a conduit 46 which has a second branch conduit 47 communicating with the space 36 above the piston 27. An air inlet 35 is provided below the piston 27. With the engine idling, therefore, the piston 27 so adjusts itself that a definite degree of vacuum, which is less than that in the manifold 1 and which depends on the adjustment of the screw 38, is maintained in the chamber 36. If now the engine speed is slightly increased, the vehicle being stationary so that the suction produced in chamber 19 is effective to draw the valve 31 to the left, the increased pressure in the chamber 20 causes the valve 21 to lift, cutting off communication between the conduits 4, 41 and connecting the latter to an air inlet 62. The spring 42 this moves the valve 40 to the left, cutting off communication between the conduits 44, 49 and connecting the conduit 46 to a conduit 43 which, through the valve 31, is at this time in communication with a conduit 50 branching from the conduit 51. The reduced vacuum in chamber 36 is thus communicated to the servo 52, and the clutch spring 17 is now effective to move the clutch parts into initial engagement. As the engine speed is further increased, the piston 23 lifts, thus causing the vacuum in chamber 36 to be diminished, and the clutching pressure thus increases with the speed until the clutch parts are rotating in synchronism. At this point, the spring 32 is effective to move the valve 31 to the right, cutting off communication between the conduits 43, 50 and connecting the latter to a conduit 61 which, through a passage 60 in the valve 40, is at this time open to the atmosphere. The clutch now engages completely.