Patent GB-684009-A (GB)
Title: Improvements in arrangements for hydraulically lifting implements carried by a tractor
IPC: A01B63/111
Filed: 1951-02-05
Abstract: 684,009. Agricultural implements. MORGEN, A. L. A. Feb. 5, 1951 [Feb. 7, 1950; April 27, 1950; May 30, 1950]. No. 2816/5 1. Class 6 (i). Relates to agricultural machines of the kind in which the implement 2 is supported from a tractor by a quadrilateral articulated linkage, the position of the implement being regulated by the ram of a cylinder which is continuously fed with oil. According to the invention, one of the members .of the linkage is so connected to the tractor that it can move bodily between two end positions when the tractor r encounters a hump or ridge of sufficient size, the said member being mechanically connected with a closing device of a discharge passage in the cylinder wall of the ram in such manner that this passage is fully closed in one of the end positions of the member r (representing its normal working position) and fully open in the other. In the construction shown in Fig. 1, the tool 2 is supported by two lower links 4 and two upper links 3, and can be raised by a linkage system 5, 6, 7, 8 associated with the piston rod 9 and piston 10 of a ram 11. The ram is permanently fed by a pump 12 and the position of the piston is controlled by a hand lever 16 which is mechanically coupled to a slide 14 co-acting with one end of a channel 13 in the piston. One of the bars 3 is pivoted at 18 to a lever 17 pivoted at 19 to the tractor, and the lever is connected to a rod 22 serving to move a device 23 which can cover or uncover a discharge port 24 of the cylinder. In normal use, the bar 3 is under compression and serves to press the lever 17 against a stop 20, the device 23 thus covering the port 24. When the tractor rides over a bump, the implement tends to lift, thus putting the bar 3 under tension and causing the slide 23 to uncover the port 24. The release of the pressure in the ram enables the implement to descend into the working position. To prevent the device 23 from operating when it is desired to raise the implement intentionally, a spring- controlled abutment 25 normally held in the inoperative position shown by a link 27a or 27b or 27c connected to a member 3 or 4 or 6, rises into the path of the limb 17b of the lever 17 and thus prevents the device 23 from uncovering the port 24. In a modification, Figs. 4 to 6 (not shown), the lever 17 and rod 22 can be uncoupled, under the action of a manual control on the lever 16, when it is desired to raise the implement. In another modification, Fig. 7, an extension 223 of the member 3 is slotted at 220 to fit over pivot 221, and serves to move a spring-controlled rod 22 whose waisted portion 22a can be brought into and out of register with the discharge passage 228 of the ram. The rod 15 in this case works in a bore in the piston 10. The device functions somewhat similarly to that shown in Fig. 1 When it is desired to raise the implement intentionally, a button 237 on the handle 16 is depressed and serves to move a rod 229 to the left where it closes the discharge passage 228. The extension 223 may be formed with a cam surface so arranged as to enable the waisted portion to move past the passage 228, thus closing the passage automatically when the implement is raised intentionally. Specifications 253,566, 470,069 and 660,841 are referred to.