Patent GB-1243945-A (GB)
Title: A change-speed gearbox, for agricultural vehicles
IPC: A01D69/06
Filed: 1970-06-26
Abstract: 1,243,945. Variable-speed gearing. DEERE & CO. 26 June, 1970 [26 June, 1969], No. 31136/70. Heading F2D. In a four forward speeds and reverse C.S.G. of a combine harvester, the C.S.G. may be moved into reverse from either of the first and second speeds without interrupting the load (i.e. power supply) and comprises a double (reverse and forward) nested clutch 10 having twin plates 24, 26 respectively fast with concentric shafts 16, 14, integral with a reverse gear 28 and forward gears 30, 32 respectively, the gears 30, 32, meshing gears 36, 38 axially retained and freely rotatably mounted on a countershaft 34 to which they may be selectively clutched by a sliding dog sleeve 40 leftwardy moved to clutch gear 36 for 2nd and 4th speeds and rightwardly moved to clutch gear 38 for 1st and 3rd speeds, a double sliding gear 58, 60 on an output shaft 54 being leftwardly moved to engage gear 60 with both a gear 50, fast on countershaft 34 and reverse gear 28 for 1st, 2nd and reverse speeds, and rightwardly moved to engage gear 58 with a further gear 52, fast on the countershaft, for 3rd and 4th speeds, the drive being controlled by the double nested clutch 10 operated by a pedal 62 which in its fully up, i.e. released position engages the forward drive clutch 20, 22, 26 and holds the reverse clutch 18, 19, 24 disengaged, and in its fully depressed condition reverses the operation, i.e. disengages the forward clutch and engages the reverse clutch, whilst in a mid-depressed position, disengages both clutches, the midposition being accurately determined by a removable locking peg 64 which prevents unintentional engagement of reverse. The ratios are as follows: First speed.-Sliding dog clutch 40 engages countershaft gear 38 and double sliding gear 60, 58 engages countershaft gear 50, clutch pedal 64 fully released engaging forward clutch 20, drive from input shaft 12, clutch 20, meshing gears 32, 38 to countershaft 34 and then via meshing gears 50, 60 to the output shaft 54. Second speed.-Same as for first speed except that the sliding dog clutch 40 engages countershaft gear 36 whereby drive from input shaft 12 passes to the countershaft 34 via meshing gears 30, 36. Third speed.-Sliding dog clutch 40 moved back to engage countershaft gear 38 and double sliding gear 58, 60 engages countershaft gear 52, drive from the input shaft 12, clutch 20, meshing gears 32, 38 to countershaft 34 and then via meshing gears 52, 58 to the output shaft 54. Fourth speed.-Same as for third speed except that the sliding dog clutch engages countershaft gear 36 whereby drive from the input shaft 12 passes to the countershaft 34 via meshing gears 30, 36 as in second speed. Reverse speed.-May be readily effected when the C.S.G. is in either the first or second speed condition, i.e. with the double sliding gear 60, 58 meshing both the countershaft gears 50 and reverse gear 28, simply by fully depressing the clutch pedal to disengage the forward clutch 20 and engage the reverse clutch 18 whereby the input shaft 12 directly reversely drives the output shaft 54 via meshing gears 28, 60, the countershaft gear 50 simply idling. All the gear ratios are additionally available on the output shaft 54 for power take-off and in addition, the steered wheels of the combine harvester can be driven by the shaft 54. To assist the operator the engaged and disengaged condition of the nested clutches can be shown on an electrical indication device.