Patent GB-658201-A (GB)
Title: Improvements in clutch-controlling mechanism for agricultural tractors
Inventor: MERRITT HENRY EDWARD
IPC: A01B67/00
Filed: 1948-10-19
Abstract: 658,201. Controlling motor vehicles. WOLSLEY MOTORS, Ltd. Oct. 19, 1948, No. 27112. [Class 79 (v)] [Also in Group XXIV] Clutch-controlling mechanism for an agricultural tractor comprises a clutch-operating rod 4 linked to a yoke 6 which is pivotally mounted on a cross shaft 2 carrying the clutch pedal 1, and a trip mechanism including a detent lever 14 pivoted on the yoke 6 on an axis parallel but spaced from that of the cross shaft 2 and normally latches the yoke 6 to the pedal 1 thereby preloading a compression spring 7 which acts between the yoke 6 and an abutment 10 on the pedal 1 so that the clutch pedal functions ordinarily until the lever 14 is tripped, either by means of an auxiliary hand clutch lever 25 which is linked to it or by means responsive to the occurrence of an overload, to allow the preloaded spring 7 to rock the yoke 6 and so disengage the clutch. As shown the clutch pedal 1 is rotatably mounted in the clutch housing 3 by. the cross-shaft 2 on which is loosely mounted the yoke 6, the pedal 1 being urged into the position shown corresponding to the clutchengaged position by a spring 13 and the pedal engaging a stop 12. The yoke is coupled by a pivot pin 5 to the clutch operating rod 4 and carries a pin 9. Between the pin 9 and a pin 8 adjustably mounted in the abutment 10 on the pedal 1 is disposed the powerful compression spring 7 and caps 11, the spring 7 urging the yoke about the shaft 6 to move the 'rod 4 to the left to disengage the, clutch. This movement of the spring 7 is prevented by the detent lever 14 which has its fulcrum on the pin 5. The lever 14 carries at one end a hook 15 normally engaging a roller 16 carried by the pedal 1 and at its other end the lever 14 is connected by a link 18 to a lever 19 and a shaft 21 journalled on a floor plate 23 of the tractor. Rigid with the shaft 21 is a lever 20 having a pin and slot connection with a rod 24 pivotally connected with the hand lever 25, which is mounted on the nearside mudguard 26 of the tractor. In the position shown the hand lever 25 is engaging a notch 27 in a guide plate 28. The clutch can be disengaged by the pedal 1 and the yoke 6 moving about the shaft 2, the detent lever 14 remaining in engagement with the roller 16 and movement of the link 18 and lever 19 not being transmitted to the lever 25 due to the pin and slot connection between the lever 20 and the rod 24. When the lever 25 is moved from the position shown in Fig. 1 to the right, after taking up the lost motion due to the pin and slot connection, the detent lever 14 pivots about the pin 5 releasing the hook 15 from the roller 16 and thus releasing the action of the spring 7 moving the yoke about the shaft 2 and disengaging the clutch. If the hand lever 25 is moved back still further, the upper surface of the lever 14 engages the cross-shaft 2 and continued backward movement causes the clutch to be re-engaged by the lever 14 and yoke 6 moving together. Release of the hand lever 25 causes the clutch to be disengaged by the action of the spring 7. To resert the trip mechanism the pedal 1 is fully depressed and due to a spring 29 between the abutment 10 and the lever 19 the lever 14 is rotated until it re-engages the roller 16. The detent lever 14 can be automatically disengaged from the roller 15 to disengage the clutch on overload by a yielding device in the draft connection of the tractor becoming displaced due to excessive pull thereon and causing deflection of a lever 31 rotating the shaft 21. Specification 658,212 is referred to.