Patent GB-702032-A (GB)
Title: Improvements in or relating to agricultural implements
IPC: A01B63/16
Filed: 1949-01-03
Abstract: 702,032. Agricultural implements. FERGUSON, Inc., H. Jan. 3, 1949 [Jan. 2, 1948], No. 44/49. Class 6 (1). [Also in Group XXIX] A ground-supported implement having a main frame which, at its forward end, can be detachably connected to the draft link of a tractor provided with a power lift device is provided with a ground wheel or support at the rear of the frame, the wheel being vertically adjustable. Furthermore hydraulic means are provided to apply an adjusting movement to the ground wheel proportional to relative movement between the draft link and the forward end of the frame in response to vertical movement of the draft link by the power lift device on the tractor. The implement 20, Fig. 1, is detachably coupled behind a tractor T having an automatic draft control in the form of a load-responsive power lift as described in Specification 470,069. The power lift device 21, which includes a one-way hydraulic ram is, rigidly mounted on the tractor and operatively connected to lower draft links 24 by crank arms 26 universally connected to drop links 28, Fig. 2. The draft links are attached to the tractor by universal pivots 29 on the rear axle housing. The admission and discharge of pressure fluid to and from the actuator to the power lift is regulated by a valve enclosed in the tractor frame 22 and having three positions, neutral, supply and exhaust. The valve may be operated by a manual control 31 to move the draft links. To move the links automatically upwards with increase in load and downwards upon a decrease in load, a stress-responsive control element is provided comprising a rockable shackle 32 and a spring biased control rod 34 connected to the valve. The implement frame 40 supports a gang of discs 42 and has adjustable ground-engaging means 44 for raising and lowering the rear of the frame. A sub-frame 45 projecting forwardly from the main frame carries a hitch frame 46 detachably coupled to the automatic draft control of the tractor. The discs are separated by spacers 48, discs and spacers being mounted on an axle skewed to the line of draft, and an adjustable scraper 49 being provided for each disc. Weight boxes 54 on the main and subframes may be used to increase the bite of the implement into the soil and to obtain proper weight distribution. The hitch frame has upwardly extending arms 56 connected by a rocktube 59, Fig. 4, and converging on to a link 60A of a two-part compression link 60. The tube 59 rocks on a shaft secured to arms 61 which are connected to the lower draft links 24 of the tractor, U-shaped brackets 64 preventing rocking movement between the links 24 and the arms 61. A strap-hook 66 engaging the rocktube forms a forward stop for the hitch frame. The ground-engaging means 44 comprises a wheel 68 journalled on a crank 69 which is mounted in a swivel fitting 70 provided with a tubular bearing 71 journalled on a shaft fixed to the frame 40, Fig. 2. An adjustable stop 76 limits movement of the ground wheel 68 towards the implement and a stop 77 limits the forward swing of the wheel during backing of the implement. Movement of the wheel towards the implement tends to raise the rearward part of the implement while the reverse movement tends to lower it. A master-actuator or ram 78 is mounted on a sub-frame 45, Fig. 1, and projecting from the ram is a piston rod 82 pivoted to one of the arms 61, so that relative movement between the sub-frame 45 and the arms 61 incident to vertical swinging movement of the draft links 24 produces relative movement between the piston rod and the cylinder of the ram 78. The master ram is connected by a flexible hydraulic conduit 86 to a slave ram 88 on the main frame 40. At one end of the slave ram is a yoke 89 pivoted on a lug 90 of the frame 40 and at the other end the piston rod 92 terminates in a clevis 94 connected to the crank 69 of the ground wheel 68 by a universal joint 95. Thus the slave ram 88 operates the ground wheel in accordance with the movements of the master ram 78. Communicating with the ram 78 is a reservoir 109, so that by opening a cock 111 the hydraulic system may be filled with oil. For working the land the main hydraulic system on the tractor is used to lower the draft links 24 and thus bring the implement down to the required working depth. The draft load to be maintained is preset automatically by a quadrant lever on the tractor. The implement is levelled during working by opening the cock 111 to allow fluid to enter the reservoir from the master ram. This shortens the stroke of the slave ram and shifts the ground wheel 68 rearwardly, thereby lowering the rear of the implement frame. The liquid flow is reversed by dropping the draft links 24 and opening the cock 111. Lateral thrust due to the engagement of the discs with the ground is in part offset by mounting the ground wheel for rotation in a plane inclined towards the implement so that the wheel 68 engages the landside rather than the bottom of a furrow. Additional means for counteracting side thrust comprises a coulter 142, Fig. 1, carried by the sub-frame 45 and journalled between brackets 149, 150. Projecting from the lower bracket 150 is an arm 151 connected to linkage 154, Figs. 2 and 4, tied to the steering mechanism of the tractor, so that steering movement at the front wheels of the tractor is reproduced in the coulter.