Patent GB-1196566-A (GB)
Title: Harvesters' Ground Speed Control
IPC: A01D41/127
Filed: 1968-10-16
Abstract: 1,196,566. Harvesters. INTERNATIONAL HARVESTER CO. 16 Oct., 1968 [23 Oct., 1967], No. 48971/68. Heading A1F. [Also in Division G3] A harvester having a power source, drive wheels and a variable ratio drive including a hydraulic motor and pump comprises two torque sensing means for monitoring the requirements of two drive means mounted on the harvester, integrating means for summing these torque requirements algebraically and control means between the integrating means and the variable ratio drive to affect the ground speed of the harvester in response to a change in torque requirements. The first torque sensing means 50 senses the torque on chain 47 on the drive means for the crop-processing driver 40 and comprises a curved arm 53 mounted for pivotal movement about pivot 54, two idlers 55, 56, and spring 57 which biases arm 53 in a counterclockwise direction about pivot 54. The idler 55 engages the slack side B of chain 47 and the second idler 56 the tight side A. As the torque requirements increase the tight side A in engagement with idler 56 causes the arm 53 to pivot clockwise against the action of the spring 57 and this movement is conveyed to the end 52 of an output link 51. The second torque-sensing means is mounted on the feeder and platform driver and includes a bellcrank 84 supported by the side wall of the harvester at 96 biased by a spring 86 and carrying idler 85 which engages the slack side of belt 84. Arm 87 pivotally connected to bellcrank 84 also carries idler 88 which engages the tight side of belt 84. Another bellcrank 89 is pivoted at 83 on bellcrank 84 and is connected via arms 90, 87 to idler 88. A second spring is attached between pivot 94 and 91. Output link 81 and clutch control link 95 are pivotally connected to the bellcrank lever 89. When the clutch is engaged the bellcrank 84 is biased in a counterclockwise position and the second idler 88 exerts a pressure on the tight side of the belt against the tension in the belt 64, spring 92 biases the idler 88 against the bias of spring 86 but is resisted by the clutch control positively held. When the torque requirements increase the tight side is under greater pressure and moves outwards causing the second idler and bellcrank lever to pivot in a clockwise direction hence moving the output link 81. An alternative embodiment of the second torque sensing means incorporates two separate pulley supporting levers joined by a link. The control means comprises casing 104 carrying pivot shaft 105 on which the speed control lever 101 is mounted, the speed control lever being connected to the drive linkage 103 which connects with the swash plate of the hydraulic pump. The lever is biased towards the fast position by spring 102 but is restrained by an adjustable maximum speed control lever 107 and integrating means comprising integrating link 121 pivotally connected to the ends of the output links 52, 82 of the torque sensors, and resultant link 122 connected via link 126 and spring 125 to the drive linkage 103. When both drivers require a high torque its links are in the full line position shown, if the feeder requires less the link 121 will assume the diagonal position shown causing link 126 to pivot clockwise about cam 142 relieving the tension in spring 125 and thus allowing the speed control lever 101 to move to a faster position and the ground speed of the harvester to increase likewise a reduction in torque in the cropprocessing drive will produce a similar result. The cam 142 forms part of feed control lever 140 which controls the sensitivity of the system by allowing the pivot point 142 to be adjusted.