Patent GB-195421-A (GB)
Title: Improvements relating to agricultural implements
IPC: A01B63/04
Filed: 1921-11-03
Abstract: 195,421. Ferguson, H. Nov. 3, 1921. Implements with adjustable tool frames; adjusting and lifting parts; travelling and propelling gear.- Ploughs, drials, cultivators, disc and other harrows. &c. connected to a tractor by superposed compression and tension members, such as described in Specification 160,248, are provided with means connected with the superposed members for automatically keeping them in the ground at a regular working depth without the use of wheels or the like on the implement. Fig. 3 shows a plough connected to a head 4 which is pivotally attached to the draw-bar 2 and abutment 3 of a tractor 1 by pins 5, 6. The plough frame 10 is connected to the head 4 by lower links 9 and a shorter upper link 11 and a double strut 12. It is raised or lowered by means of a lever 15 projecting from a hollow cross-head 16 which is mounted on a bolt 17 and is provided with arms 18 connected by a laterally adjustable link 19 to the head 4. The lever 15 is provided with a locking pawl 21 operated by a trigger 23, rod 24, and lever 25. The depth of work is adjusted by means of a screw 33 passing through a ball nut 34 and connected to an arm on the cross-head 16. A spring 26 is connected by an adjusting screw to the frame and by a bent spring link 27 to the arms 18. The spring tends to lift the plough when the latter is in the raised position and to depress it when it is deep in the ground. When the plough is at work the weight .is taken by the tractor and the landsides 30 do not bear on the bottom of the furrow. The dropping of the rear wheels 31 of the tractor into a hollow, for instance, tends to increase the depth of ploughing but the additional resistance thus caused turns the ploughs around the pivots 38 of the strut 12 and thus depresses the cross-head 16 so that its connection with the screw 33 causes it to turn on the bolt 17 and lift the ploughs. In the modification shown in Fig. 6, two V-shaped struts 35 are bolted together by a bolt 36 and the depth of work is adjusted by means of a screw 41 screwed into an extension of the cross-head 16 and bearing on a plate 46. The lower links 9 are connected to the head 4 by short links 44 and are turned upwards and bent over at their forward ends to engage the links 44 and limit the relative movement of the links 9, 44. The lines of the links 9, 11, Fig. 3, intersect at a point z in front of the rear wheel axle and below the draw-bar 2, so that the line, of draught is low and does not pass through the hitch point a. The weight of the tractor holds the plough in the ground. When the plough strikes an obstacle the pull on the links 9 and push on the link 11 tends to raise the rear wheels of the tractor from the ground and thus relieve the stress on the implement and prevent the tractor from overturning backwards. In the examples shown, all the mechanism for adjusting and controlling the implement is carried on the implement itself. The plough frame may be tilted laterally by adjusting the link 19 by means of a screw. The arrangement may be such that there is no lateral swing- ing about the pins 5, 6. The links 9, 11 may be connected directly to the tractor by universal joints, and the landsides may be provided with plates to run on the bottom of the furrows.