Patent GB-523954-A (GB)
Title: Improvements in or relating to clutches
IPC: F16D23/12
Filed: 1938-11-18
Abstract: 523,954. Operating clutches. BORG-WARNER CORPORATION. Nov. 18, 1938, No. 33579. Convention date, Jan. 31. [Class 80 (ii)] Consists in clutch-operating mechanism for motor vehicles such mechanism being structurally separate from the clutch and including a speed responsive governor driven from the engine and mechanically connected with a member adapted to operate the clutch, in such a manner that, at speeds below a predetermined value the governor holds the clutch disengaged against the action of the clutch packing springs while at higher speeds the governor permits the clutch packing springs to hold the clutch in engagement. As shown in Fig. 1, the clutch 2 of a motor vehicle is normally engaged by internal springs and is disengaged by anticlockwise movement of an arm 20 secured to a rocker shaft 19 having a yoke 18 acting on the clutch collar 17. The arm 20, acted on by an adjustable spring 22, has a pin-and-slot connection with a rod 21 connected to the clutch pedal 5 and also has a pin-and-slot connection with a rod 25. A drum 32, Fig. 2, mounted in a housing 26 secured to the engine 1, and driven from the latter, as from the generator 28 through a flexible coupling 31, pivotally carries weights 33 provided with arms 35 which coact with a thrust collar 36 on the rod 25 under the action of springs 37. Below a predetermined speed, the springs 37 overcome the centrifugal force of the weights and the pressure of the clutch springs so as to maintain the clutch disengaged. Above that speed, the weights move centrifugally outwards so as to relieve the pressure on the rod 25 and allow the clutch springs to produce engagement of the clutch. Disengagement can, however, be effected by depression of the pedal 5. Engagement below the predetermined speed can be effected by anticlockwise movement of a lever 7 connected by a rod 40 to a lever 41 acting on a shoulder 42 on the rod 25. Alternatively, the manual control 7 may be dispensed with and the rod 25 divided into sections 25a and 25b, Fig. 6. A servo cylinder 45, communicating with the engine intake manifold through a conduit 46 provided with a restriction, is secured on the section 25b, while the servo piston 47 is connected to an arm 49 which is pivoted at 50 to the section 25b and at 51 to the section 25a. So long as the engine is operating with normal relatively-high induction vacuum, the piston 47 occupies the position shown, in which the axial separation of the sections 25a and 25b is a minimum, and the action is set out above. If, however, the engine stops or runs at low speed under high torque, the induction , pressure approaches atmospheric and the piston 47 moves to the right, so as to allow the clutch springs to engage the clutch. The Specification as open to inspection under Sect. 91 describes a modification in which the centrifugal weights act on the rod 25 in the other direction, the rocker shaft 19 is arranged above instead of below the clutch shaft, and the springs 37 are dispensed with, the spring 22 being made strong enough to overcome the clutch springs. Thus, above the idling speeds the weights move the rod 25 to the left, so as to permit clutch engagement, while below idling speed the spring 22 produces disengagement. This subject-matter is not in the specification as accepted.