GB2069811A - Storing silage - Google Patents

Abstract

An apparatus for storing and feeding silage comprises a bunker silo 10 for storing the silage and unloading elements operating on the top surface of the silage to feed silage from the silo, the silo having vertically collapsible walls. Suitably, two auger-type unloading elements of an unloading assembly 12 are mounted on a wall-supported rail 18 for end-to-end movement over the silo 10. The auger-type unloading elements are each divided into two helices of opposite hand so that on rotation by frame-mounted motors they operate on the top surface of the silage to discharge silage into appropriately positioned feeding troughs 20. By having the side walls 14 of the silo vertically collapsible, the vertical positions of the two unloading elements can be continually adjusted so as to maintain them at all times in contact with the upper surface of the silage. <IMAGE>

Description

1

GB 2 069 811 A

1

SPECIFICATION

Improvements in and relating to storing and feeding silage

5

This invention relates to an apparatus for storing and feeding silage.

During the winter months, when fresh grass is not available, dairy cows are fed a diet of two main con-10 stituents, namely a bulky basic ration of hay, straw or silage and a supplementary concentrated feed. The bulky ration is needed to keep the rumen working properly and to keep the overall cost of feed as low as possible. Concentrate feeds supplement the 15 bulky ration by balancing the energy and protein in the ration and providing minerals and any other "extras" needed.

When manual labour is relied upon throughout, the two operations of storing and feeding the silage 20 will take up more time, with a typical dairy herd, than any other single task apart from milking. Besides being unattractive work, this means that too little time is available for herd management and for the care of individual animals.

25 In an attempt to reduce the labour requirements per cow and to ensure optimum usage of expensive concentrated feeds, these feeds are often fed in a controlled manner at the point of milking or in a special feeding area, often either automatically or by 30 remote control. Unfortunately, however, the machinery required in these establishments is expensive and someone has often to be in full time attendance to control the machinery and guard against mishaps.

35 A further alternative is to mechanise the whole process by storing the silage in tower silos fitted with an unloaderto provide so called "automatic" unloading. In the system, concentrates are mixed into silage as it leaves the tower silo (using weighers 40 and proportioning devices to meter the correct amount of each additional component of the feed) and the partially mixed feed is delivered to the cows by conveyors and feeders. Unfortunately such a highly mechanised system is particularly vulnerable 45 should part of it break down because it is very difficult in such cases to unload the tower by improvised means.

By way of contrast, horizontal or bunker silos do not readily lend themselves to automatic unloading, 50 and operator-controlled machines e.g. a tractor with foreloader or a tractor-mounted machine or block-cutter, have generally been used instead. As this means that the silage is not unloaded steadily, the added concentrates have to be mixed in using a 55 batch method and machines, such as mixer wagons, for this purpose have therefore also to be provided if complete diet feeding is to be achieved. Despite this, however, bunker silos do have advantages over tower silos. For example the overall cost is less 60 because the equipment used to fill them is not so expensive. They are also more flexible in use and because they are not so dependent on good weather during the ensiling period, they often allow a better forage to be ensiled before its quality begins to 65 decline with age.

Another feature of bunker silos as compared with tower silos is that the animals can be allowed to help themselves to the feed by pulling it out of the silo. This is called self feeding. Unfortunately, however, 70 the ration cannot be controlled precisely in these cases, and considerable wastage can occur. Moreover, complete diet feeding is, of course, not possible. Accordingly, automatic unloading machines have been developed in the past which 75 work at an end face of the bunker silo and unload the silo from one end, working along the axis of the silo to finish at the other end. However, the supporting framework in these cases has to be strong and heavy to withstand the forces imposed on the unloader 80 when cutting a vertical face and also the machines deliverthe silage not to a fixed point but to one that inconveniently moves along the silo as it is unloaded. Forthese and other reasons, the machines have not been taken up commercially and, 85 as indicated earlier, a tractor with foreloader or some other conventional piece of equipment is invariably adopted instead.

Afirst object of the present invention is to provide an apparatus for automatically unloading bunker 90 silos which will at least to some extent avoid the problems mentioned above in respect of earlier attempts at automatic unloading.

In practice, the depth of bunker silos has generally been limited by wholly practical considerations e.g. 95 by the need for the cows to reach the silage to feed themselves, or by height limitations imposed by the unloading machinery, or because the structure of the silo is not strong enough to contain a greater depth of silage. Accordingly, conventional bunker silos 100 tend to be relatively wide for ready access to the silage and to compensate for their shallow depth. However, this relatively large area of exposed silage aggravates the risk of excessive aerobic deterioration which has been found to take place when the 105 silage is exposed to airfor a prolonged period e.g. the two or three days that will typically occur before the exposed silage is removed and fed to the cattle.

A second object of the present invention is to reduce the losses of total feed value of the silage due 110 to aerobic or other deterioration arising because the silo has to be opened and silage removed.

An apparatus for storing and feeding silage according to the present invention comprises a bunker silo for storing the silage and one or more unloading 115 elements operating on the top surface of the silage to feed silage from the silo, the silo having vertically collapsible walls allowing the or each unloading elementto move down with the silage as the amount of silage in the silo is reduced. The term "vertically 120 collapsible walls" in this context means walls the height dimension of which iscontrollably variable irrespective of the inclination of the wall to the vertical.

Evidence from experiments suggests that aerobic 125 deterioration is less likely to occur in the silage prior to unloading in a top unloaded silo than it will if a substantially vertical face of the silage is exposed. This point has still to be proved conclusively however.

130 Furthermore the apparatus of the present inven

2

GB 2 069 811 A

2

tion allows the exposed top surface area of silage to be less for the same volume of silage than it would be in wide shallow silos and this in itself should significantly reduce the risk of aerobic deterioration. 5 Conveniently, the or each unloading element comprises an auger and in preferred embodiments the or each auger has its two halves of opposite-handed helices so that one auger half will move silage to one side of the silo while the other auger half 10 will move silage to the opposite side. In one such embodiment two such contra-rotating augers span the full width of the silo and operate to discharge silage from the space between the two augers but three or more augers may be provided instead if 15 desired. Other unloading mechanisms engaging with the silage surface may be used e.g. scrapers, cutting chains or rakes, if desired.

It is calculated that in a typical embodiment of the present invention, the silo might be loaded with sil-20 age to a settled height of about 4.5 m in use. This means that if the silage is unloaded from the top at a typical given rate of demand e.g. a 25mm layer each day, it should lastforthe usual winter feeding period of about 180 days.

25 Conveniently, the or each unloading element may be supported from the silo walls or it may be partly or wholly supported from the silage surface by one or more depth control members (e.g. rollers or wheels) engaging this surface. As an alternative to 30 controlling the depth of cut by wheels or rollers, optical, laser or lead wire systems may be used instead, if desired.

Level, pitch and roll may also be controlled automatically to keep a level surface to the silage and 35 ensure regular distribution of silage to the troughs etc., placed at the foot of the silo walls as hereinafter described.

Conveniently the one or more unloading elements are mounted on a frame moved from end to end of 40 the silo by a suitable chain and sprocket system or by a winch or windlass. Alternatively the silo can be unloaded in sections which are unloaded down to floor level before the machine moves to and unloads the next section. In this latter case, extra conveyors 45 may be needed to take silage from the section being unloaded to troughs associated with the sections not being unloaded or, as an alternative, the amount of trough space allowed for each animal may be restricted. Moreover, the cutting mechanism can 50 need from two to three times more power when cutting a vertical face than is ordinarily required.

Several supplementary feed constituents, or concentrate feeds can be held in bins sited nearby or carried on the unloader and, according to a preferred 55 feature of the invention, metering means are provided whereby these feeds are metered onto the silage in the proximity of the one or more unloading elements so that they are thoroughly mixed into and delivered to feeding troughs etc. with the silage. In 60 one such embodiment, control mechanisms are also provided to enable the proportions of the added feeds to be changed and different rations to be fed from place to place along the silo.

Conveniently, the or each unloading element may 65 itself be mounted for sideways displacement to a new lateral position enabling it to deliver more silage to one side of the silo than the other e.g. so that different groups of cows may be fed differently according to their needs. In the double helix version of the auger-type unloading elements, for example, this sideways displacement will result in the centre line of the elements (where the helices change direction) no longer corresponding to the centre line of the silo.

The need for massive and expensive walls to withstand the pressure exerted by the considerable depth of silage that will be present in the fully loaded silo, is avoided in the present invention by the bottom-supported flexible walls of the silo which yield a little to the silage pressure and thereby reduce it. A bunker silo having such walls is seen as representing another aspect of the present invention irrespective of whether or not these walls are vertically collapsible and whether or not unloading elements etc., are also present.

Conveniently, each vertically collapsible wall of the silo comprises flexible sheeting e.g. stretched over a support beam itself supported on a series of folding strut devices.

Conveniently, the sheeting comprises individual sheets of which adjacent sheets overlap one another to present an airtight surface to silage in the silo.

Conveniently, alternate sheets of the sheeting pass over a first support beam and the intervening sheets pass over a second support beam supported from the first support beam by spacer means.

When the unloading elements are mounted on a frame, then conveniently the frame is mounted on wheels running along support rails carried by the collapsible side walls of the silo, each said rail being supported from the second support beam by spacer means staggered in relation to the spacer means between said first and second beams.

Preferably the wall includes jacking means acting on the folding strut devices to control the height of the wall.

Conveniently, the flexible walls can be made of strong but flexible sheeting, for example polyester fibre-reinforced polyvinyl chloride sheeting or a rope assembly or webbing lined with polyethylene sheet providing only that the walls have a suitable spring rate eg. 60-100 N/mm per m run or the length of the wall for a wall height of 4.5 m.

The walls of the silo in the apparatus of the present invention should, of course, have no stanchions or other obstructions which might prevent the unloading element or elements moving freely from end to end of the silo as the walls are progressively lowered during unloading.

Either end of the sheeting can be clamped against tensioning loads or by load imposed by the silage. Furthermore, the clamps can be repositioned and the length of sheet between them shortened as the wall is let down. Conveniently, any spare sheeting from the silo walls can be rolled up on rollers.

Conveniently, the outer parts of the side walls (e.g. sheeting) slope away from the silo and can be used to act as a chute to guide unloaded silage to a feeding or transport location e.g. into troughs positioned at the foot of the silo walls. In this case, because the

70

75

80

85

90

95

100

105

110

115

120

125

130

3

GB 2 069 811 A

3

cows walk to the silo to feed, no other machinery or tractors are required for mixing, feeding or transporting the feed. The silage unloading element is relatively simple in itself and the apparatus only 5 requires machinery for metering additional feed components onto the silage. If a mechanical breakdown should occur the cows can be fed by hand with much less effort than with tower-based systems.

In order to be able fully to unload the silo, the silo 10 floor is preferably raised e.g. built higher than any troughs and winding-up rollers present so that silage can slip downwards uninterrupted into the troughs.

It will be appreciated that the end walls of the silo can be rigid walls, flexible walls or vertically-15 collapsible walls, e.g. of the kind above described, depending upon how the silo is to be filled or emptied.

A basic embodiment of the invention will now be described, by way of example only, with reference to 20 the accompanying drawings in which:-

Figure 1 is a general diagrammatic perspective view of one end of an apparatus according to the present invention;

Figure 2 is a perspective view, showing, on an 25 enlarged scale, part of the unloading elements and related drive assembly used in the apparatus of Figure 1;

Figure 3 is a plan view of part of the same apparatus showing the unloading elements in their 30 entirety;

Figure 4 is a perspective view of the internal structure of a self-stabilised collapsible wall (shown in an extended state) parts having been omitted or broken away for clarity;

35 Figure 5 is a side view of the internal structure of a post-stabilised collapsible wall as it will appear when the wall is extended, once again with parts omitted or broken away for clarity;

Figure 6 is a perspective view, on an enlarged 40 scale, of one end of the wall structure of Figure 5 showing the form of the end-posts in more detail;

Figure 7 is a similar view to Figure 5 but with the wall sheeting totally omitted and the structure partially collapsed.

45 Figure 8 is a diagrammatic cross-section of a collapsible wall of the apparatus with the wall raised and the silo empty and showing take-up rollers and a locking device for the wall sheeting.

Figure 9 is a similar view to Figure 8 as it will 50 appear when the silo wall is raised and with the maximum height of settled silage in the silo; and

Figures 10(a), 10(b) and 10(c) are side views of alternative designs of depth control for the unloading assembly.

55 Thus referring first to Figure 1, an apparatus for feeding and storing silage comprises a bunker silo 10 for storing the silage and an unloading assembly 12 operating on the top face of the silage to feed silage from the silo into troughs placed at the bottom 60 of opposed vertically-collapsible walls of the silo. In the view of Figure 1, only one such wall (14) is visible. The silage-engaging surface of this wall is provided by sheets of flexible sheeting 16 and the wall carries one rail 18 of a pair of top rails for supporting 65 the unloading assembly in its end-to-end traverse of the silo on wheels 19. Reference numeral 20 indicates the feeding trough associated with wall 14.

The collapsible walls of the silo may be either self-stabilised (as shown in Figure 1) or post-stabilised as shown in Figures 5 to 7. Figure 4 shows the internal structure 21 of a self-stabilised wall 14 as comprising two folding strut systems 22,23 supporting top beams 25,26 from two base pads 28,29 which are bolted to a reinforced concrete floor (not shown).

Hollow centre beams 31,32 of the two systems are mounted on opposite sides of their associated struts to be kept accurately in alingment with one another by a central core member 33 common to both systems. Tie members 36,37 linkthe adjacent pivots of the two systems and a mechanical jacking means 39 acting between one pair of oppositely-acting pivots 42,51 of the two systems enables the wall structure to be jacked up or down to different heights during operation of the apparatus. In the unlikely event that the chain 44 of the jacking means should break or that the ratchet mechanism 46 should malfunction and allow the chain to slip, a back-up safety chain 48 is provided between the other pair of like-acting pivots 50,51. At one of its ends, the saftery chain is provided with a hook which can be manually engaged (at position 53) with an appropriate new link of the chain wherever the wall height has been reset.

It will, of course, be appreciated that if the centre beams 31,32 of the two systems are to be aligned with one another as above described, then the remainder of the two systems must be offset. In particular it will be observed that each strut system is pivotally connected to the outer side of a different one of the two top beams 25,26, and that these two beams are interconnected by a longitudinal base member 54 of a rail assembly 55 of which the top rail 18 is supported on spacers (such as spacer 58) from an intermediate member 59 itself supported on spacers (such as spacer 60) from the base member 54. The purpose of having the rail assembly constructed in this way is to allow adjacent sheets of the flexible sheeting 16to be draped with sufficient overlap to provide air-tight joints between them where they contain the silage mass whilst at the same time leaving top rail 18 free to support the unloading assembly as above described.

In an alternative version member 54 is omitted and intermediate member 59 is supported by spacers 60 directly from top beams 25,26.

This arrangement of the sheets is more clearly seen by reference to figure 5 where they are shown in place on a post-stabilised wall structure having substantially the same rail assembly 55 as that shown in Figure 4, with the spacers 58 staggered relative to the spacers 60 to allow the necessary overlap between the sheets. In Figure 5, reference numerals 62-66 represent the external faces of the adjacent sheets shown and numerals 68-72 indicate the internal sections of the same five sheets.

The manner in which each sheet passes from ground level over the associated support beam of rail assembly 55 and back again to ground level is best seen from Figures 8 and 9 which, as already indicated, show the walls 14 as they will appear with the wall raised and the silo empty (Figure 8) and full

70

75

80

85

90

95

100

105

110

115

120

125

130

4

GB 2 069 811 A

4

(Figure 9). For clarity in these two Figures, the sheets

74 of one set of alternate sheets has been shown in

" full line and the sheets 75 of the other set of alternate sheets has been shown in broken line and slightly 5 displaced from the sheets of the first set.

Thus referring now to these two figures, the outer faces of both sets of sheeting slope down from the rail assembly 55 to act as a chute for silage discharged from the silo by unloading elements (not 10 shown). To enable this chute action to be continued throughout the unloading process, the silo base is constructed with a raised concrete floor 77 built to a higher level than troughs 20 and the wall sheets 74,

75 are clamped to the corner edge of this floor by a 15 clamp 79. They then pass over their respective support members in rail assembly 55 and back via adjustable clamps 81 to storage rollers 83,84 which take up the slack in the sheeting when the wall is collapsed from the fully extended positions shown in

20 Figures 8 and 9 to lesser heights consistent with a reduced amount of silage in the silo.

In essence, adjustable clamps 81 each comprise a square section core member 86 trapped in a ground-supported hollow beam construction 87. As 25 will be seen from the drawings, the hollow beam construction 87 presents a lateral slot in its innerface through which a section of the sheeting can be passed for wrapping around the core member 86 of the clamp. When it is desired to reduce the height of the 30 wall, for example, the jacking means 39 is first operated to lower the rail assembly 55 to a lower level than that required. The slack in the now untensioned wall sheeting can then be easily passed around core member 86 for take up on storage rollers 83,84. 35 When sufficient slack has been taken up in this way, jacking means 39 is again operated but this time to expand the over-collapsed wall back to the desired new height. The resulting upward pull on the wall sheeting 16 will cause the core member 86 to be 40 pulled to the position shown in figures 8 and 9 where it co-operates with the slot-defining edges of beam construction 87 to clamp the bottom of the sheeting in place against the tensioning forces imposed on it by the re-expanded wall.

45 In an alternative version (not shown) the beam construction 87 may be reversed to have the clamping slot facing outwardly.

It is, of course, important that the silo base 90 should be constructed in such a way as to be able to 50 withstand the upward forces imposed on it by the clamped ends of the wall sheets (due to tension in the sheets) while at the same time supporting the downward force imposed on it by the internal structure 21 of the wall.

55 Returning now to Figures 5 to 7, it will be observed that the internal structure of the post-stabilised collapsible wall shown there has much in common with the structure of Figure 4 and accordingly the same reference numerals have been used to indicate simi-60 lar or similarly operating parts in the two designs.

The principal difference between the two constructions is that the wall structure of Figures 5 to 7 lacks both the alignment feature provided by parts 31-33 in the earlier embodiment and also the upwardly 65 converging top sections to the struts when the wall is extended (it will be observed that in the design of Figure 5, these strut sections actually diverge). The lack of these two features in the design of Figures 5 to 7 means that the wall structure illustrated there is unstable as regards side-to-side movement in the plane of the silo wall. This instability arises whenever the top sectionsofthe beam-supporting struts are parallel and there is no tensioned sheet over the top beam to provide lateral stability as in the case when the wall is initially lowered for unloading to commence. It is solely to stop movement of the wall in this plane that the end posts (92,93) have to be provided.

The construction of these posts is best seen from Figure 6, from which it will be seen that each post in fact comprises a pair of uprights 95,96 supporting a = sliding cross-member 98. This member is itself engaged by co-operating surfaces of the rail assembly 55 so as to allow different inclinations of the silo wall as the amount of silage in the silo and/orthe height of the walls is varied. During erection, locking pegs (such as peg 100) may be used to hold the top of the wall in position until the wall sheeting is tightened. Then the pegs are removed.

Although not shown in Figures 5 to 7, it is to be understood of course that a jacking mechanism e.g. similarto that shown in Figure 4, will be provided to alter the height of the wall and desirably a safety mechanism e.g. once again similar to that shown in Figure 4, will also be provided to stop unintentional collapse of the wall.

It will be noted that only two sets of struts have been shown in the embodiments of Figures 4 to 7,

but of course it goes without saying that as many sets as needed can be used for the silo walls provided only that they are suitably interconnected to give the desired performance. Equally, if desired, the sheeting for each wall could be provided by a single sheet instead of by a number of lapped sheets as shown in the illustrated embodiments.

Other variations will be apparent to those skilled in the art. For example instead of a manually operated mechanical jacking means to lower and raise the ? walls electrical or hydraulically operated jacking systems could equally well be used. If desired, these manually operated systems could instead be automatically operated.

Referring now to Figures 2 and 3, the auger-type unloading elements 102,103 of assembly 12are mounted on a rectangular frame 105, each being driven through an associated gearbox 107 and coupling 108from a respective motor 109 mounted atone end of the frame.

Two sub-frames 111,112 each mounted on a pair of carriages 114,115 for limited transverse movement across the frame, carry the wheels 19 which support frame 105 on support rails 18. The transverse movement of carriages 114,115 allows the wheel-to-wheel spacing of the frame 105 to vary with the wall-to-wall spacing of the silo as this latter changes with different silo loadings e.g. from the 3° inclination shown in Figure 8 to the 7° inclination shown in Figure 9. Reference numerals 117 indicate stops to prevent excessive side-to-side movement of the carriages.

70

75

80

85

90

95

100

105

110

115

120

125

130

5

GB 2 069 811 A

5

The vertical positioning of sub-frames 111,112 relative to main frame 105 is controllably adjusted by manually-operated mechanical jacks 119 to vary the depth of silage removed from the silo at each pass of 5 the frame 105. This is diagrammatically indicated in Figure 10(a). Other methods of depth control are indicated in Figures 10(b) and 10(c) as will be hereinafter described.

In addition to support wheels 19, the sub-frames 10 111,112 also carry five sprocket wheels 121,122 about which passes a stationary chain 124 the opposite ends of which are clamped to the silo base as shown.

Of these sprockets, all are free-wheeling except 15 the centre sprockets 122 which are driven from a motor 126 via telescopic drive shafts 128,129 through the usual chain drive and gear box 131,132.

The motor 126 and the associated drive mechanisms are all rigidly mounted on centre beams 134, 20 135 of the frame 105 and to ensure that these beams at all times remain over the centre line of the silo, the two sub-frames 111,112 are interconnected by a Stephenson's linkage 137,138,139 the centre member 138 of which is pivotted at the exact centre 25 point of the frame (point 140). Universal joints 142,

143 are provided in the shafts 128,129 to take account of the misalignment that will occur as a result of the Stephenson's linkage moving from the position shown in Figure 2 or as a result of a change

30 in the depth control provided by jacks 119 (Figure 3). In alternative versions (not shown), these jacks may be replaced by any other appropriate jacking means whether manually or automatically operated.

It will be observed from Figure 2 that the auger-35 type unloading elements 102,103 are each divided into two helices of opposite hand so that on rotation by frame-mounted motors 109 they operate on the top surface of the silage to discharge silage along the sloping outer faces of the side walls 14 into the 40 appropriately positioned feeding troughs 20. By having the side walls of the silo vertically collapsible the height of the walls can be reduced to suit the amount of silage remaining in the silo so that throughout the unloading operation silage can be delivered over the 45 walls as above described and into the troughs.

As already mentioned above, there is more than one way in which depth control can be achieved and some of these are shown diagrammatically in Figures 10(a) to 10(c) in all of which the direction of 50 traverse is from right to left and reference numeral

144 indicates the silage. Figure 10(a) represents the arrangement of Figures 4 to 7 in which the height of the unloaderframe 105 above support rails 18 can be varied by mechanical jacks 119. In the arrangement

55 of Figure 10(b), depth control is obtained by a silage-engaging depth control roller 145 carried on a support member 147 which pivots between two extremes of travel to lie just ahead of whichever is the trailing auger at the time. In the arrangement of 60 Figure 10(c), two telescopically mounted depth control rollers 149,150 are provided with each roller close to the inner side of one of the two augers 102, 103.

It will be apprecitaed that whereas with the 65 arrangement of Figure 10(a) both augers 102,103

will be operating as already described, in the arrangements of Figures 10(b) and 10(c) only the trailing auger will be driven, the leader auger being allowed to "freewheel" along the surface of the silage. When the unloader reaches the end of a traverse, the drive is transferred to what in the return traverse will become the trailing auger and the previously driven auger (now to become the leading auger) is allowed to freewheel. During the initial part of this return traverse, it will be understood that until the newly driven auger reaches the position finally occupied by the previously driven auger, the unloader will cut double the depth preset by the depth control rollers.

As already mentioned, a second aspect of the present invention resides in the provision of a silo with bottom-supported flexible walls which can yield a little to silage pressure and thereby reduce it. Although the silo walls illustrated in Figures 4 to 7 clearly fulfil this requirement, it will be appreciated that if the unloading mechanism is not to operate on the top surface of the silage, for example if a conventional unloading system is to be employed, then it is not necessary, according to this second aspect of the invention, that the flexible walls should be vertically collapsible. Thus designs of sheet-supporting structure otherthan those illustrated in Figures 4to 7 could equally well be used provided always, of course, that they are bottom-supported structures. Similarly there appears to be no good reason why the inner face of the wall sheeting should not be joined to an external ground-supported clamp and take-up rollers by straps or other convenient means instead of by continuing the sheeting over the top of the wall structure and all the way down to the ground-supported clamp as in the illustrated collapsible-wall versions. Nevertheless the ability of the silo walls to be able to vary their inclinations with different silo loading appears still to be an important feature to be retained in preferred embodiments consistent with this second aspect of the invention.

In modifications of the various embodiments described above, the movement of the unloading elements is controlled from a control panel. In these arrangements the lowering screw-jacks at either end of the unloader are driven in pairs by electric motors through gear boxes and chain drives and 5 seconds after the augers are started (as timed by a time clock in the control panel), the depth-control jacks are automatically operated to lower the unloading assembly by a pre-set amount, a make and break switch counting the revolutions of each pair of jacks and actuating a counter in the control panel to control the amount lowered. The traverse motor then moves the unloading assembly across the silage for a pre-set number of passes. After the final pass, the traverse stops and there is a timed delay before the augers stop to allow them to clear. The cycle is repeated when next the time clock switches on. Limit switches prevent over-running of any component and there are manual controls for maintenance purposes.

Claims (1)

1. An apparatus for storing and feeding silage comprising a bunker silo for storing the silage and

70

75

80

85

90

95

100

105

110

115

120

125

130

6

GB 2 069 811 A

6

one or more unloading elements operating on the top surface of the silage to feed silage from the silo, the silo having vertically collapsible walls allowing the or each unloading element to move down with

5 the silage as the amount of silage in the silo is reduced.

2. An apparatus as claimed in Claim 1 in which the or each unloading element comprises an auger.

3. An apparatus as claimed in Claim 2 in which

10 the or each auger has its two halves of opposite-

handed helices so that one auger half wil I move silage to one side of the silo while the other auger half will move silage to the opposite side.

4. An apparatus as claimed in Claim 3 in which

15 two such contra-rotating augers span the full width of the silo and operate to discharge silage from the space between the two augers.

5. An apparatus as claimed in any preceding claim in which the or each unloading element is

20 supported from the silo walls.

6. An apparatus as claimed in any of Claims 1 to 4 in which the or each unloading element is partly or wholly supported from the silage surface by one or more depth control members engaging this surface.

25 7. An apparatus as claimed in any preceding claim in which the one or more unloading elements are mounted on a frame moved from end to end of the silo by a chain and sprocket system.

8. An apparatus as claimed in any preceding

30 claim in which the or each unloading element is mounted for sideways displacement to a new lateral position enabling it to deliver more silage to one side of the silo than the other.

9. An apparatus as claimed in any preceding

35 claim in which each vertically collapsible wall of the silo comprises flexible sheeting.

10. An apparatus as claimed in Claim 9 in which the sheeting is stretched over a support beam itself supported on a series of folding strut devices.

40 11. An apparatus as claimed in Claim 10 in which the sheeting comprises individual sheets of which adjacent sheets overlap one another to present an air-tight surface to silage in the silo.

12. An apparatus as claimed in Claim 11 in which

45 alternate sheets of the sheeting pass over a first support beam supported from the first support beam by spacer means.

13. An apparatus as claimed in Claim 12 when including the limitations of Claim 7 in which the

50 frame is mounted on wheels running along support rails carried by the collapsible side walls of the silo, each said rail being supported from the second support means by spacer beam staggered in relation to the spacer means between said first and second

55 beams.

14. An apparatus as claimed in any of Claims 10 to 13 in which each collapsible wall includes jacking means acting on the folding strut devices to control the height of the wall.

60 15. An apparatus as claimed in any of Claims 9 to 14 in which the sheeting is clamped against tensioning loads or by load imposed by the silage, and storage rollers are provided to take up any spare sheeting from the silo walls.

65 16. An apparatus as claimed in any preceding claim in which the outer parts ofthe side walls slope away from the silo and can be used to act as a chute to guide unloaded silage leaving the silo.

17. An apparatus as claimed in Claim 16 in which 70 the silo floor is built higher than any troughs and winding-up rollers present so that silage can slip downwards uninterrupted into the troughs.

18. An apparatus as claimed in Claim 1 and substantially as hereinbefore described with reference

75 to, and as illustrated in. Figures 1 to 3 ofthe accompanying drawings.

19. An apparatus as claimed in Claim 1 and substantially as hereinbefore described with reference to, and as illustrated in. Figure 4 of the accompany-

80 ing drawings.

20. An apparatus as claimed in Claim 1 and substantially as hereinbefore described with reference to, and as illustrated in. Figures 5 to 7 ofthe accompanying drawings.

85 21. An apparatus as claimed in Claim 1, and substantially as hereinbefore described with reference to, and as illustrated in, Figures 8 and 9 ofthe accompanying drawings.

22. An apparatus as claimed in Claim 1 and sub-90 stantially as hereinbefore described with reference to, and as illustrated in. Figure 10(a) or Figure 10(b) or Figure 10(c) ofthe accompanying drawings.

23. A bunker silo having bottom-supported flexible walls which yield a little to the silage pressure

95 and thereby reduce it.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd., Bsrwick-upon-Tweed, 1931.

Published atthe Patent Office, 25 Southampton Buildings, London, WC2A1 AY, from which copies may be obtained.