GB2111375A - Apparatus for unloading silage from a bunker silo - Google Patents

Abstract

A cutter 21 is mounted on a gantry-supported carriage 17 which can be moved along the gantry 10 to cut a "slice" of silage from an exposed vertical face of a stack of silage in a bunker silo 15. Silage from the cutter 21 is conveyed upwardly by an elevator 23 for discharge to a transport belt 30 moving along the top of the gantry structure to deliver silage over one or other side wall of the silo. A hopper 35, 36 at either end of the gantry enables concentrates to be added prior to discharge from the belt 30. Optionally a consolidating vibratory device (not shown) and a grass-spreading mechanism (not shown) can be fitted to the gantry for use during loading of the silo. <IMAGE>

Description

SPECIFICATION Improvements in and relating to apparatus for unloading silage from a bunker silo The present invention relates to apparatus for unloading silage from a bunker silo.

At present, most of the silage made in the UK is stored in bunker silos or "clamps" as they are sometimes called, the material conserved being known as the stack. As silage can only be stored successfully in an oxygen-free environment, it is important that the walls of the silo should be airtight and for this reason they are often lined with polythene sheeting which is also used to cover the top surface of the silage. When eventually the silage is required for feeding, the polythene sheeting is removed from part of the top of the silage stack and an area of silage is exposed to the air at what is usually known as the working (or exposed) face of the stack.

Various tractor-mounted devices are already available for removing silage from the working face of the stack. These comprise (1) a reciprocating knife or fixed blade cutter which is forced through the silage to cut off material from the stack; (2) a rotating cylinder-type cutter in which projections attached to the cylinder 'gnaw' the silage on to a conveyor; (3) an auger which removes silage from the stack and deposits it in a container; and (4) a chain saw mechanism which cuts and removes the silage as blocks of silage.

In most of these existing arrangements the tractor will be required not only to power the relevant device but also to transport the silage to the animals to be fed. Indeed, depending on the herd size and the distance between the feeding area and the silos, the tractor could be in use for a total of 1-2 hours per feed. Where the silage is supplemented with concentrated feeds, additionai time must also be allowed for mixing the concentrates with the silage and the tractor will again be required together with an unloading mechanism for the concentrates and usually a trailer.

Occasionally stock may be allowed to eat the silage direct from the working face of the stack but this can cause high wastage and can make the addition of supplementary feeds difficult. It also presents a problem with the handling of slurry because of particles of silage mixed in it. Under some conditions this direct-feed technique can also increase wastage through selective eating by the stock.

According to the present invention, an apparatus for unloading silage from a bunker silo comprises cutter means for cutting a slice of material from an exposed face of the silage stack and comminution means for comminuting the slice of material as it leaves the cutter means.

Preferably, the apparatus will be arranged for operation on an exposed vertical face of the silage stack in which case the cutter means and the comminution means are conveniently mounted on a support means allowing them to travel from end to end of the exposed face of the silage stack. One way in which this can be done is to have the cutter means and the comminution means supported on a gantry structure spanning the width of the exposed face and displaceable towards said face to allow successive slices of silage to be cut off from the stack.

Conveniently, the comminution means comprises an elevator e.g. of the plate or buckettype or alternatively of the "en masse" type, designed to comminute the silage as it conveys it away from the cutter means.

Conveniently a deflector plate or the like will be fitted to guide silage from the cutting means to the elevator.

Where a gantry structure is provided, for example, the elevator might conveniently discharge the comminuted silage on to a transport belt running lengthwise of the gantry structure and adapted to discharge from one or other end of the structure comminuted silage received from the comminution means.

Conveniently, hoppers are provided over the transport belt for the addition of material e.g.

concentrated feeds or other supplementary feed, to the comminuted silage before this is discharged frorn the transport belt.

Conveniently, the gantry structure will be movably supported on the top edges of opposed walls of the silo or other structure and the transport belt will be operative to discharge the comminuted silage iand any additives present) into feeding troughs at the bottom of the walls.

Conveniently, the transport belt is provided with load cells to allow the rate of feed to the stock to be measured.

The cutter means may take a number of different forms but, in each case, the cutter means should preferably be mounted for limited pivotal movement about an axis located transversely to the direction of movement of the cutter means during cutting of the silage slice thereby enabling the cutter means to cut itself "into" and "out of" the slice at the beginning and end of the cutting operation.

It is a disadvantage of known cylinder-type cutters and known auger cutters that although they produce the desired in situ break up of the unloaded silage, they also disturb the silage remaining in the silo. This will allow air to enter the silage stack thereby encouraging aerobic deterioration. On the other hand although known reciprocating knife, fixed blade and chain saw cutters, produce minimum disturbance in the silage stack, they fail to break up the silage. The apparatus of the present invention overcomes both these drawbacks, however, insofar as it both provides a clean cut at the exposed face of the stack and delivers the removed silage in comminuted form.

It should be made clear at this point that the terms "comminution" etc. used in the context of the present invention are not to be interpreted as implying that what may be termed the "particle" size of the silage is in any way reduced. On the contrary, all that is intended by the term "comminution" is that the silage should be broken up to much the same particle size as it might be if unloaded with a mechanical fork for example.

Although the invention is primarily concerned with the unloading of silage from a bunker silo, the need to consolidate the silage-producing grass during loading is well known. This consolidation process expels air from the stack and accelerates the development of an oxygen free environment thereby reducing the'potential for aerobic deterioration when the stack is stored for feeding.

Accordingly, in those embodiments of the present invention using a gantry structure to support the cutter means and the comminuting means, it is envisaged that the same structure could advantageously be used to support a consolidating roller or plate for the stack.

Conveniently a vibrating roller or vibrating plate might be used for this purpose. It is also envisaged that the same support structure could be used to carry means for spreading the grass more evenly as it is loaded into the silo prior to consolidation.

Apart from the obvious convenience of utilising the gantry structure in these other ways, it should also be borne in mind that the improved method of consolidation provided by the gantry-mounted roller or plate might now make it possible to introduce transverse plastic sheets in the stack as it is formed, thereby further safeguarding against the deep penetration of air into the silage stack.

Although the cutting means can be of any convenient form, a chain saw type of mechanism with or without a ledger plate is currently favoured. However a cutter in the form of a single strand of wire may sometimes be advantageous.

For maize, a simple cylinder-type cutter may be best.

An embodiment of the example will now be described, by way of example only, with reference to the accompanying drawing which shows, somewhat diagrammatically, a simplified isometric view of a bunker silo fitted with silage unloading apparatus according to the present invention.

Thus referring now to the drawings, a gantry structure 10 running along the opposed walls 12, 13 of a bunker silo 1 5 supports a carriage 1 7 mounted for wall-to-wall movement across the width of the silo.

The silage cutter 21 and elevator 23 are carried by a framework 24 which is pivotally connected to the carriage 1 7 at 25 to permit the cutter and elevator assembly to be swung clear of the stack and allow it to pass over the stack without touching it, e.g. during the filling of the feed troughs and during consolidation or grass spreading if the appropriate attachments (not shown) have been fitted to the gantry.

Channel members 26 of the framework 24 allow the chassis of elevator 23 to be repositioned if necessary to take account of any unevenness in the floor of the silo 1 5.

Although for convenience a plate type elevator has been shown at 23, a suitable bucket, plate or en masse elevator will normally be preferred. In each case, a deflector plate 28 will usually be mounted on framework 24 behind the cutter 21 so as to deflect silage from the cutter to the comminuting elevator 23.

At its upper end the elevator 23 will discharge the comminuted silage through the open top of the carriage 1 7 onto a transport belt 30 running between the two I-beams 32, 33 of the gantry structure 10. As an alternative to I-beams, lattice types may be used if desired. The belt 30 can be driven in either direction so as to discharge the comminuted silage over one or other wall 12, 13 into an appropriate feeding trough 14 at the bottom of the wall.

Hoppers 35, 36 are mounted at each end of the structure 10 to allow concentrates to be added to the silage before discharge from the belt 30.

Although for convenience the cutter 21 has been shown as a simple cutting wire, as already explained a chain saw cutter will often be preferred or, in some cases, a simple cylinder-type cutter. In all events, it is desirable that the cutter should be able to be moved "into" and "out of' the silage slice as near as possible to the silo walls 12, 13 and for this reason the cutter and the deflector plate 28 are both mounted for limited pivotal movement about pivotal connections 38, 39 with the framework 24.

In operation of the assembly described above, the reievant vertical face of the silage stack is first exposed to the air by removing the corresponding sheets of polythene from the stack and, with the carriage 17 next to side wall 13, the gantry 10 is advanced to engage the cutter with the exposed face of the stack.

The cutter at this stage will be oriented so as to have its line of action as close to wall 1 3 as possible. Thus, as viewed in the drawing, the cutter will have been pivoted in an anticlockwise sense about pivots 38, 39.

Once engaged with the silage face, the cutter is pivoted clockwise (as viewed in the drawing) so as to cut itself into the silage to the depth required for the slice to be cut. At the end of this pivotal motion, the cutter will have adopted the orientation shown in the drawing with its cutting plane parallel to its intended direction of movement along the I-beams 32, 33.

The carriage 1 7 is now driven across the silo with the cutter 21 operating to remove a slice of silage from the exposed face of the stack. As this slice leaves the cutter it is deflected onto the elevator 23 for discharge by belt 30 into one or other feed trough 1 4 as above described.

Just before the cutter 21 reaches the opposed wall 1 2 of the silo, the traverse of carriage 1 7 is stopped and the cutter is once again pivoted about pivots 38, 39 (in the clockwise sense as viewed in the drawing) to cut itself out of the silage without any significant disturbance of the stack. If more silage is to be removed, carriage 1 7 is returned to wall 1 3 and the above process is repeated.

In an alternative embodiment (not shown), the deflector plate 28 is arranged to deflect material to one or other side of the cutter 21 so that in this case the second slice can be cut in the reverse direction i.e. with the carriage 1 7 moving back towards wall 1 3. In this case, of course, the cutter 21 will not be removed from the silage at the end of the first slice. Instead, it will be further advanced into the silage in a manner analogous to that already described for commencement of the first slice.

Metering devices are fitted to the hoppers 35, 36 to allow the appropriate weights of concentrate to be added to the silage prior to discharge. Load cells fitted to belt 30 enable the total amount of material fed to the stock to be weighted.

Advantages of at least the preferred embodiments of the present invention when compared with the prior art arrangements are that: the area of silage exposed to the air at the end face of the stack is relatively small; the cutting mechanism should not significantly disturb the silage remaining in the stack; the silage can be delivered direct to the feeding troughs; load cells may be provided to allow the silage to be weighed; concentrates can be added in a known and controlled rate; the ratio of silage/concentrates can be varied easily; no tractor is required during loading, unloading or filling the feeding troughs; and the apparatus can readily cope with herds of varying size. It will be understood of course that if necessary the silage can be delivered into a trailer instead of into the troughs 14.

The various moving parts of the illustrated apparatus will normally be powered by hydraulic or, for example, electric motors though, for simplicity, these have not been included in the drawing. Reference numeral 14 indicates a chain and sprocket connection between the output of one such motor and the carriage 17.

Claims (16)

1. An apparatus for unloading silage from a bunker silo comprising cutter means for cutting a slice of material from an exposed face of the silage stack and comminution means for communiting the slice of material as it leaves the cutter means.

2. An apparatus as claimed in Claim 1 arranged for operation on an exposed vertical face of the silage stack.

3. An apparatus as claimed in Claim 2 in which the cutter means and the comminution means are mounted on a support means allowing them to travel from end to end of the exposed face of the silage stack.

4. An apparatus as claimed in Claim 3 in which the cutter means and the comminution means are supported on a gantry structure spanning the width of the exposed face and displaceable towards said face to allow successive slices of silage to be cut off from the stack.

5. An apparatus as claimed in any preceding claim in which the comminution means comprises an elevator designed to comminute the silage as it conveys it away from the cutter means.

6. An apparatus as claimed in Claim 5 in which the elevator is of the bucket, plate or en masse type.

7. An apparatus as claimed in any preceding claim in which a deflector plate or the like is fitted to guide silage from the cutting means to the elevator.

8. An apparatus as claimed in any preceding claim when including the limitations of Claim 4 in which the elevator operates to discharge the comminuted silage on to a transport belt running lengthwise of the gantry structure and adapted to discharge from one or other end of the structure comminuted silage received from the comminution means.

9. An apparatus as claimed in Claim 8 in which hoppers are provided over the transport belt for the addition of material to the comminuted silage before this is discharged from the transport belt.

10. An apparatus as claimed in Claim 8 or Claim 9 in which the gantry structure is movably supported on the top edges of opposed walls of the silo or other structure and the transport belt is operative to discharge the comminuted silage, and any additives present, into feeding troughs at the bottom of the walls.

11. An apparatus as claimed in any of Claims 8 to 10 in which the transport belt is provided with load cells to allow the rate of feed to the stock to be measured.

12. An apparatus as claimed in any preceding claim in which the cutter means is mounted for limited pivotal movement about an axis located transversely to the direction of movement of the cutter means during cutting of the silage slice thereby enabling the cutter means to cut itself "into" and "out of" the slice at the beginning and end of the cutting operation.

13. An apparatus as claimed in any preceding claim when including the limitations of Claim 4 in which the gantry structure used to support the cutter means and the corn minuting means is also used to support a consolidating roller or plate for the stack.

14. An apparatus as claimed in Claim 1 3 in which the consolidating roller or plate is a vibrating roller or vibrating plate.

1 5. An apparatus as claimed in any preceding claim when including the limitations of Claim 4 in which the gantry structure to support the cutter means and the comminuting means is also used tc support means for spreading the grass more evenly as it is loaded into the silo prior to consolidation.

16. An apparatus as claimed in any preceding claim in which the cutter means is a chain saw type of mechanism with or without a ledger plate, a single strand of wire, or, for maize, a simple cylinder-type cutter.

1 7. An apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.