Patent GB-517650-A (GB)
Title: Improvements in or relating to gapping machines for thinning turnip, mangold, beet and other crops
IPC: A01B41/04
Filed: 1938-08-05
Abstract: 517,650. Machines for thinning turnip and other crops. KENT, H. C. Aug. 5, 1938, No. 23136. [Class 6 (i)] Consists in improvements in machines for thinning turnips &c. described in Specifications 440,372 and 459,548. According to the invention, the machine comprises a frame with travelling- wheels and having a rotary gapper consisting of two disc-like bladed members mounted on a longitudinal shaft, these members being adapted to enter the ground substantially edgewise in a plane transverse to the path of the machine, the bladed members being clamped together and being relatively adjustable angularly to provide for varying the size of the blade gaps and consequently of the bunches of plants left by thinning. Two forms of machines are described, one for use with plants sown in drills or ridges, and the other for plants sown on the flat. Fig. 2 shows the " drill " machine, in which a main frame 1, with steering handlebars 4, has travelling-wheels .3, the shaft 5 of which is geared at 6 to a longitudinal shaft 7. This shaft carries a bladed gapping device 10 comprising a pair of dished disc-like members 10a, 10b, Fig. 9, each having two quadrantal blades 10c, Fig. 3. The front disc 10a is clamped by bolts 17 to the rear disc. which is fixed by a boss 16 to the shaft 7. Slots 18 are provided for the clamping bolts 17 to allow angular adjustment of one member relatively to the other. A further adjustment for varying the spacing between the plants may be made by changing the ratio of the bevel gearing 6. The leading edges of the front blades are separately sharpened. A scraper 19, Fig. 9, cleans the front face of the gapping device, and a lateral guard 20 prevents soil &c. from being thrown by the the rotating gapper on to the adjacent row of plants. To provide for variation of the cutting depth of the gapper, two supporting wheels 21a, 21b are mounted behind the gapper on vertically adjustable posts, these wheels being adapted to run on the top of the drill at the sides of the row of plants. The wheel 21b is mounted for swivelling movement about a vertical axis, to reduce the effect of impact by a stone thrown up by the gapper. An auxiliary frame 11, pivoted to. the main frame at 12, carries side wheels 14 running in the furrows between the drills and drill-cleaning discs 13. The discs and wheels. are resiliently held on the ground by springs 15 connected between the handlebars 4 and vertical. extensions of the frame 11. Steering is controlled by a lever 38, connected to a swivelling cross-member 39, which is centrally pivoted to the main frame and is connected to the drawbars 2. The lever 38 moves within a guide 41, provided with pins 42 to hold the lever in any adjusted position. In the machine for use on flat ground, Figs. 11 and 12 (not shown), the auxiliary rear frame 11 is omitted, and the travelling-wheels are provided with ratchets and pawls to facilitate steering. The cutting depth of the gapper is adjusted by vertical adjustment of rear wheels which support the main frame. An auxiliary spring-controlled frame is pivoted to the front of the main frame, and carries a pair of vertically adjustable plough-like members which clear away clay, weeds &c. from the sides of the plant row in front of the gapper. Additional cleaning- members, spaced further apart, may be provided on the rear crossbar of the main frame.