GB2124868A - Seed sower - Google Patents

Abstract

Seeds or fertiliser are dispensed in accurately metered quantities and in spaced-apart rows by means of a horizontal tube 4 mounted to rotate about an axis transverse to the direction of travel, and containing a single detachable helix 5 throughout its length. Spaced inlets 6 (Fig 2) and outlets 7 along the length of the tube form separate spaced dispensing arrangements for the individual rows, all using the same metering helix. <IMAGE>

Description

SPECIFICATION Metering of discrete articles This invention relates to the metered delivery of discrete articles, primarily of seeds in seed drilling equipment, but is applicable also to the metering of other materials in the agricultural and horticultural field, for example granularfertilisers of a kind that require two be delivered only very sparsely.

It is well knownthatthe broadcasting of seeds very wasteful and various methods are available for metering them out. Ideally only a single seed is required in each hole, and atthe same time no hole should be left unseeded, and so the known methods have involved striving to place each seed in its own pocket in a delivery path, for example a perforated belt. In one known arrangement, such a belt, passing below a hopper, is intended to pick up just one seed in each hole, and then photo-electric cells checkfor complete filling. Another known method involves a rotary disc dipping into a hopper and having suction applied to holes in its face over one arc of its movement to pick up the seeds, then pressure is applied to the holes in a different part ofthe arc, to discharge the seeds picked up.

Clearly, methods involving the use of photo-electric cells orsources of vacuum and pressure are relatively expensive. Other methods in commercial use involve cups dipping into a hopper and picking up individual seeds. However all these known methods, even the sophisticated and expensive ones, cannot cope perfectly with the fact that seeds are far from uniform in size and shape; in the purely mechanical methods, seeds that are too large ortoo small can become crushed and then form a blockage that halts the whole operation.

In certain patent specifications it has been proposed to dispense seeds or other material bythe use of a drum rotating about a horizontal axis beloworwithin a hopper and containing an internal helixthat propels the material axially to an outlet point. For example in British Patent Specification No. 859 841 there is disclosed such a method in which the drum is of substantial diameter and the seeds are formed into a line between two guide plates. Such an arrangement has no sorting effect, and is relatively bulky and complexfor delivering only a single line of seeds. In U.S. Patent Specification 4 222 502 a metering arrangement is shown for powdered abrasive material in which a rotary horizontal tubular member having an internal thread has one end immersed in a hopper and the other end in atmosphere. Again this is a relatively complex structure for a simple task.

The aim of the invention is to provide a simple way of metering outseeds and similar discrete articles or granular materials of somewhat uncertain size and shape, suitable for use under rugged agricultural or horticultural conditions and capable of depositing two or more separate lines of material simultaneously with the minimum of equipment; a furtheraim is to allow flexibility and adaptability to suit different materials with the minimum of difficulty.

According to the invention we propose that appar atusfor mounting on a n an agricultural or horticultural vehicle for dispensing seeds or other discrete or granular material should comprise a tube adapted to be mounted for rotation about an axis transverse to the direction of travel ofthevehicleand containing a detachable helix inserted so asto lie against its inside wall, and the tube having at least two axially spaced inlets and at least two respectiveaxiallyspaced outlets, each spaced in the same direction in relation to its associated inlet, and each inlet being placed to receive material from a hopper (which may or may not be common to each or all of the inlets).

In this way it is possible to deposit seed orfertiliser in accurately metered quantities in each oftwo or more laterally spaced furrows or lines, yet with only a single rotary dispenser. In atypical example there could be as many as six separate lines of seed or fertiliser deposited, all using the same tube.

Thefactthatthe helixisdetachablemakesiteasyto withdraw it from one end ofthetube and replace it with another helix of different pitch, so as to alterthe quantity dispensed for a given number of revolutions.

The helix is conveniently of springy wire, wound to a free diameter equal to, or a shade greaterthan, the inside of the tube; it may be of round wire, or wire of square or even flat rectangular cross-section, the best profile being settled by experimenting with the particular material to be dispensed. The pitch of a given wire can be altered within limits simply be stretching it axially or compressing it.

The tube is preferably transparent, for example being of commercially available substantially rigid transparent plastics, so that the operatorcan monitor the behaviour of the device continuously. It is carried in spaced journal bearings, and these bearings can conveniently be aligned at the positions of the inlets and/or outlets, so that the material for example falls from the hopperthrough the bearing and into the rotary inlet port each time the latter comes round.

There are preferably guides or hoses into which the material falls from the dispenser outlets, allowing the material to be deposited on or in the ground exactly where it is wanted.

The rotation of the tube can be effected by a ground-engaging wheel which is capable of being lifted clear of the ground by the operator when delivery is to be halted, orthe tube could be driven by an electric motor, the speed ofwhich is determined by a sensor responsive to ground speed. The latter arrangement makes it easierforthe operator to be given an overriding control of the rate of delivery.

The invention will now befurther described by way of example with reference to the accompanying drawings, in which: Figure 1 is an exploded view of the equipment comprising a single hopper with six points at which material is admitted to the tube and correspondingly six outlets; and Figure 2 is a diagrammatic view of a partofthetube toa largerscale.

The drawing(s) originally filed was/were informal and the print here reproduced is taken from a later filed formal copy. The equipment shown comprises a long hopper 1, preferably of non-corrodable material such as glassreinforced plastics, adapted to be mounted on a tractor or, preferably, a specially designed four-wheel mobile seed-planting machine having a wide track and shortwheelbase (not shown). The hopper 1 has its longer axis transverse to the direction of travel and in the floor 2 there are six outlet points, to each ofwhich thefloorslopes down as shown. Each outlet point leads into a journal bearing 3 and, mounted to rotate within these bearings is a long straight tube 4 of plastics, running the full length ofthe hopper.Inside the tube and running its full length is a single hel ix 5 of springy wire (best seen in Figure 2) secured to the tube at its ends and of a diameter such as to be a good fit in the tube and not move freely, yet to be capabie of being withdrawn and replaced by a different one when desired.

Within each bearing 3 the tube 4 has a rectangular opening 6 (see Fig. 2) in its wall; axially spaced from it is a similar opening 7forming an outlet and placed adjacent to the next bearing. Atrough-like casing 8 around the tube (shown spaced below it in the interests of clarity) carries spigots 9 leading to outlet guide hoses 10 placed below the outlet openings of the tube, so that the material dispensed, e.g. seed or fertiliser, is placed exactly where it is required.

Thetube4isrotated by any convenient means, as indicated above, for example by a ground-engaging wheel, capable of being lifted clear when necessary, on the vehicle. The ratio in the drive, for example by pulleys, is readily changeable to alterthe number of revolutions performed by the tube for a given distance travel led.

Experience shows that, if the pitch ofthe helix is arranged to match the maximum dimensions of the material, e.g. seeds, to be dispensed, the seeds tend to sortthemselvesoutasthehelix rotates so that, after five or six turns, there is almost invariably only one seed perturn. The seeds tend to back up atthe inlet end and so although gravity is urging more seeds in at the inlet end all the time, only one seed per revolution is discharged atthe outlet end. This is what achieves the accurate metering, and forthis reason there should be at least five complete turns of the helix between each inlet and its associated outlet. In practice there is no problem in this, since the rows to be planted are generally further apart than this anyway.

Even where the material to be dispensed is in the form of small granules, e.g. offertiliser, and they are individually much smaller than the pitch of the helix, a similaraccurate metering efect is obtained, inthata substantially similar number of granules settles down in each turn of the helix.

Itwill be appreciated that individual hoppers could be used instead of a single one, and the outlets instead of(orinadditionto)theinletscould be located at bearing points. Certain of the inlets and/or outlets could be blanked offwhere seed-drilling isonlyto be at a wider spacing than the pitch between outlets.

The tube 4 itselt is preferably easily removable for cleaning, and this can be done without disturbing the rest of the equipment.

The outlets 7 could all lie on a common axial line so that seeds are depositied simultaneously in all six rows, but as an alternative they could be at different angular positions, so that seeds in adjacent rows are staggered.

Claims (6)

1. Apparatus for mounting on an agricultural or horticultural vehicle for dispensing seeds, fertilizers or other discrete or granular material comprising a round tube adapted to be mounted with its axis horizontal and transverse to the direction of travel of the vehicle and to be rotated aboutthat axis, the tube containing a detachable helix inserted so as to lie against its inside wall and the tube having in its wall at least two separate axially spaced inlets and at least two respective axially spaced outlets, each spaced in the same direction in relation to its associated inlet, and each inlet being placed to receive material from a hopper, the helix extending at least through those parts of the tube containing each or all of the said inlets and outlets.

2. Apparatus according to claim 1 in which an outlet is adjacentto the next inlet with which it is not associated.

3. Apparatus according to claim 1 or claim 2 in which the or each inlet and/or outlet is aligned within a bearing in which the tube rotates.

4. Apparatus according to any one of claims 1 to 3 including guide tubes or hoses aligned with the outlets to receive and guide the emerging material.

5. Apparatus for dispensing seeds, fertiliser or other discrete or granular material, substantially as described with reference to the accompanying drawings.

6. An agricultural or horticultural vehicle equipped with apparatus according to any one of claims 1 to 5.