GB2124991A

GB2124991A - Shrouded belt elevator

Info

Publication number: GB2124991A
Application number: GB08223006A
Authority: GB
Inventors: Wilfred Erwin Klinner
Original assignee: NAT RES DEV; National Research Development Corp UK
Current assignee: NAT RES DEV; National Research Development Corp UK
Priority date: 1982-08-10
Filing date: 1982-08-10
Publication date: 1984-02-29
Also published as: GB2124991B; DE3327864A1

Abstract

A shrouded belt elevator 10 comprises two belts 12, 13, the load- engaging runs of which move within and are constrained by a tube or trough-like constraint member 17. In an alternative embodiment, a belt or belts are divided into a load-accepting section and a shrouded load-elevating section by belt-shaping means constrained to shape the belt or belts into a load- embracing configuration. <IMAGE>

Description

SPECIFICATION Shrouded belt elevator The present invention relates to belt elevators and in particular to shrouded belt elevators.

Using a tubular constraint to completely enclose the belt of a belt elevator, not only prevents material spillage but the tube itself provides sufficient structural strength to allow a major portion to be cantilevered and to serve as the support for terminal rollers, delivery chutes or spouts, delivery enhancing impelling rotors and rollers, retarding shields, extension or secondary conveyors, etc.

The use of tubular constraint members also results in compact structures and makes variation of the inclination of the elevator probably easier to achieve than with other types of elevator.

If the tubular constraint member is made of impact resistant material and has a degree of resilience, then the risk of damage from collisions and fatigue will be minimal.

Belt elevators in which the top run of a loadsupporting belt moves within and is constrained by a circular-section tube or trough have already been proposed in US Patent Specification 3212628 and UK Patent Specification 1497945.

It is an object of the invention to improve upon these prior designs.

According to a first aspect of the present invention, a shrouded belt elevator comprises two belts, the load-engaging runs of which are adapted to move within and be constrained by a tube or trough-like constraint member.

Conveniently, the load-engaging runs of the two belts are inclined to one another in a V-form configuration at the intake end of the constraint member.

Conveniently, in this latter case, at the delivery end of the constraint member, the load-engaging runs of the two belts are parallel to one another. Alternatively, however, they may also be disposed in a V-form or inverted V-form configuration.

Conveniently, where the relative inclinations of the load-engaging runs vary along the length of the constraint member, the two belts pass at the delivery end of the constraint member about two roller-type supports inclined lengthwise of the constraint member to compensate for the effect of this varying belt inclination and encourage equal tension at both edges of the two belts.

Conveniently, the load-engaging runs of the two belts may be everywhere spaced apart so that drive means may be provided for optionally driving the two belts at different relative speeds, e.g. to enable the load to be discharged at different lateral trajectories at the delivery end of the elevator and/or to achieve a rolling and compacting effect on the load during its passage through the constraint member.

According to the second aspect of the present invention, a shrouded belt elevator comprises one or more belts having, or each having, its operative run divided into a load-accepting section and a shrouded load-elevating section by belt-shaping means contoured to shape the belt or belts into a loadembracing configuration.

Thus in an alternative design of twin-belt elevator to that described above, load-engaging runs of the two belts running flat side by side in the loadaccepting section of the elevator are suitably shaped longitudinally and transversely in the concave transition region leading to the shrouded load-elevating section by a bed-plate underneath the belts and by an appropriately shaped roller means above the belts.

Conveniently, in this case, the roller means takes the form of a single, central, downwardly-sprung roller, pneumatic wheel or sphere or it takes the form of two rollers, pneumatic wheels or hemispheres arranged side by side, one on each belt.

Conveniently, the load-engaging runs of the two belts are disposed horizontally or near-horizontally in the load-accepting region.

As an alternative to the twin belt systems described above, a single wide belt may be shaped at the intake end of the constraint member so as at least in part to embrace the load on entering the constraint member.

Conveniently, in this case, the belt is suitably shaped for its passage through the constraint member by one or more spring-loaded shaping rollers or roller assemblies arranged at the intake end of the constraint member. As an alternative to hard rollers (whether carrying a resilient covering or not), an inflated pneumatic wheel or wheels e.g. of spherical or near-spherical shape, may be used, if desired, or an inflated pneumatic roller or rollers might be employed.

Conveniently, the width of the belt is significantly greater than the largest cross-sectional dimension of the constraint member.

Conveniently, at the delivery end of the constraint member, the conveying belt is guided into the return run by a direction-changing delivery roller whose position is adjustable to minimise the formation of a pocket by the belt in the delivery region.

Additionally, or alternatively, the delivery roller axis may be rotatable to encourage delivery of the belt-engaged load to one or other side of the elevator. The same effect may be achieved instead, however, by having a multi-part constraint member with at least one part able to swivel sideways relative to the adjacent part or parts about the longitudinal constraint member axis.

The delivery roller spindle is preferably springloaded so as to be able to accommodate shortening of one edge of the belt when the delivery roller axis alone or the constraint member is swivelled as above described.

In one particular single-belt embodiment of the elevator, the belt may be twisted through up to 1800 during its passage through the constraint member, necessitating the belt to return above the constraint member rather than below it as will usually be the case with the other single-belt embodiments so far described.

Although in the embodiment of the invention a constraint member of circular or part-circular crosssection is conveniently employed, polygonalsection, and in particular square-or rectangular section constraint members are also well suited.

Where the constraint member is of circular or part-circular cross-section, inserts are preferably provided within the constraint member to lift the belt clear of much of the inner wall of the constraint member. This reduces the frictional forces exerted on the belt.

A friction-reducing effect is also achieved if the shroud-engaging surface of the belt or belts is transversely or longitudinally ribbed or corrugated.

It will often be convenient for both single belt and twin belt embodiments to have the belt or belts guided to form a horizontal or near-horizontal loadaccepting region prior to entry into the constraint member.

Conveniently, in this case, the drive means for the belt or belts is provided upstream of the loadaccepting section, so that the belt or belts are pushed towards the concave transition region and into the constraint member.

Conveniently, in-work changes in inclination of the constraint member may be effected to vary the delivery point of the elevator.

Conveniently, adjustment means are provided at the intake end of the constraint member for varying the pressure exerted on the belt or belts by the spring-loaded, bend-forming rollers, wheels or spheres etc.

Conveniently, an impeller rotor is provided at the delivery end of the constraint member to accelerate the load and allow its discharge into a container relatively remote from the delivery end of the elevator.

Although able to operate with differing types of load, the embodiments of the present invention are especially suited to the transporting and loading of powder materials, granular materials e.g. seeds or grain, aggregate materials including gravel and coal, long and chopped fibrous materials and small unit loads.

The gripping capacity of the load-embracing belts may be enhanced if the load-engaging surface is transversely ribbed or corrugated.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of a twin-belt elevator according to a first embodiment of the invention; Figure la is a section in the direction of arrowsA-A in Figure 1 showing the flow and return belts; Figure 2 is a side view of a twin-belt elevator according to a second embodiment of the invention; Figure 2a is a plan view on arrow B in Figure 2 showing the intake region of the constraint member; Figure 2b is a section in the direction of arrows C-C in Figure 2 showing the belt bed plate in chain dot line; Figure 2c shows an alternative belt-shaping roller to that illustrated in Figure 2a; Figure 2d is a view on arrow A in Figure 2;; Figures 2e and 2f illustrate alternative belt and constraint member configurations looking down the constraint member; Figure 3 is a side view of a single-belt elevator according to a third embodiment of the invention; Figure 3a is a plan view corresponding to Figure 2a for the previous embodiment Figures 3b and 3c are a cross-section and a sectioned plan view of a friction-reducing arrange ment for the embodiment of Figures 3 and 3a; Figure 3d is a sectioned plan view of an alternative friction-reducing arrangement; Figures 3e to 3h show alternative belt and constraint member configurations looking up the constraint member; Figure 3i shows a device for urging the beltshaping roller or rollers on to the belt or belts; Figure 4 is a side view of a single-belt elevator according to a fourth embodiment of the invention;; and Figure 5 is a side view of the intake end of a constraint member showing a convenient tube sup port frame.

Referring first to Figures 1 and 1 a, these show an elevator 10 in which two load-engaging belts 12,13 pass in a straight line between pairs of rollers 14, 15 at each end of a tubular shroud 17.

At the intake end of shroud 17, the rollers 14 are inclined to each other to form a V, whilst at the delivery end, the rollers 15 lie axially parallel. The purpose of this form of belt guidance is to enable the material to be fed between the belts from one side so that even small quantities of material are positively gripped on reaching the converging part of the V-shaped space between the two belts, shown in the cross-sectional view of Figure la.

The material is introduced into the elevator 10 directly from a chute or by a lateral feed conveyor 19 which may be horizontal, as shown, or inclined to the horizontal and at different lateral angles. A suitable funnel arrangement 21 at the intake region and a V-shaped plate (not shown) covering the space between the belts beneath the funnel help to prevent spillage.

Either the upper or the lower rollers may be driven, the latter providing the simpler and cheaper solution.

Each roller at the delivery end is supported on arms 23, 24 which are pivoted at attachment points 26, 27 on the tube, and the rollers are spring-loaded towards each other as shown, for the second embodiment, in Figure 2d. A stop (not shown) may be provided to keep the pairs of rollers at 14 and 15, and hence the belts 12, 13, apart a given distance.

This enables the two belts to be driven optionally at different speeds. Advantages of this are that acceptance of material at the feed-on point is improved, a rolling action is imparted to the material trapped between the belts, leading to compaction with some materials, especially fibrous crops, and the stream of material emanating from the delivery rollers 15 is directed to one side away from the faster-moving belt run. The last aspect may be used to deliver crop, for example, in different directions laterallywhen belt speed is adjusted in work, e.g. by hydraulic motors or a variator drive. The speed of only one belt needs to be adjusted.

Although the tubular shroud shown is circular in cross-section, other sections are suitable, including V-section of different enclosed angles, with and without side extensions, which may be at an angle to each other or parallel sided. This last configuration is shown in Figure 2f for the second embodiment of the invention.

The alternative conveying ducts discussed above may be open at the top in parts or throughout their length. The belts used may be of suitable widths to cover all or part of the side walls, depending on the materials to be conveyed, the throughputs required and the elevating angle.

Optionally also the belt rollers at the delivery end may have their axes, instead of parallel, inclined to each other to form a V or inverted V of the same or different enclosed angle as the lower rollers.

With reference now to Figure 2 of the drawings, this shows a twin-belt elevator 30 in which the principal belts 32,33 are guided to form a horizontal, or, preferably, slightly inclined, intake region 35. An optional hopper 37, consisting in its simplest form of one or two vertical or slightly inclined plates or boards 39,40, guides the material onto the two belts running flat and closely adjacent to each other beneath it.

A large-diameter roller 42, preferably a pneumatic tyred wheel, is so suspended by arms 44, 45 and spring loading means (not shown) that it forms the belt on to a concave bed plate 47 shown in chain dot outline. The plate is shaped so that it forms a smooth transition from the flat and substantially horizontal belt plane in the intake region into the inclined and transversely curved belt run within the tubular shroud. Another view of the plate is given in Figure 2b, which is a view in the direction of arrows C-C, the bed plate again being shown in chain dot outline.

Upstream of the flat section, turned-over edges 49, 50 of the bed plate 47 guide the outer edges of the belts and, in conjunction with the central roller 42, prevent the inner edges of the belts parting. Indeed, depending on the inclination to each other of the intake and elevation sections of the belts, overlap can occur at times to a small degree of the inner belt edges as they pass through the concave bend into the circular-section shroud 52.

When material is present on the belts, the spring loaded roller 42 rises to run on top of the material but continues to apply pressure to the belt indirectly through the material layer.

The intake end of the tube or shroud 52 may be shaped as shown in Figures 2 and 2a. Alternatively it may be cut at right angles to the longitudinal tube axis or in such a way that an upper protuding lip only just clears the intake roller 42 throughout its arc of movement. This latter arrangement has the advan tage of helping material to feed into the tube.

Figure 2c shows an alternative bend-forming, belt-shaping roller 53, ideally made of plastic or other resilient material and inflatableto appropriate pressures. Another even more suitable shape is a spherical inflatable roller, as shown in Figures 3 and 3a for the third embodiment of the invention.

If the two belts 32,33 in Figure 2 are to be driven at differential speeds, then two pneumatic tyred wheels side by side or two hemispherical rollers on the same transverse spindle will be needed in place ofthesingle rol ler 42.

Preferably in all cases, but not exclusively, the drive to the belts is by the roller 54 upstream of the hopper 37, so that the two belts are pushed into the concave bend leading to the intake end of the shroud. A secondary nip or snubbing roller (not shown) may be necessary in close proximity of the driven roller in the return run of the belt beneath the hopper region in order to improve belt traction by increasing the wrap around the drive roller. An alternative drive may be provided if directionchanging roller 57 is driven in association with one or two nip or snubbing rollers.

The return rollers 55,56 at the delivery end are angled in the vertical plane to be further upstream at the bottom, as shown in the side view of Figure 2.

Having the rollers inclined to the length of tube 52 in this way re-instates equal tension at both edges of each belt 32, 33 after twisting during the passage through the tube. As will be clear from Figure 2, the belts return initially alongside the tube 52, gradually turning and moving beneath the level of the tube, to be finally guided by a direction changing roller 57 beneath the intake end of the tube.

Figure 2dis a view on arrowA in Figure 2 and shows a simple roller suspension and spring loading system. It also shows that, if the tube 52 is square or rectangular in cross-section, it may be cut at the delivery end so that a length of the base of the section may optionally be left protruding downstream for the purpose of forming a lip 59 to prevent spillage and guide the material into a compact stream.

Figure 2e is a section through an alternative, square-section, tube in the centre region of the elevator, showing the attitude of the two belts 32,33 when looking down the tube. However, as mentioned earlier, the return rollers may be inclined at an angle to each other in the form of a V or an inverted V in which case the belts would assume attitudes different to those shown in Figure 2e.

Figure 2f is a section through an alternative shape of tube already discussed in relation to the first embodiment of the invention.

In Figure 3, a tubular elevator 61 is shown in principle similar to that of Figure 2 and hence the same reference numerals have been used where appropriate. However elevator 61 differs from the previous design in employing only one belt 63. No bed plate is necessary under the feed portion, and the bend-forming roller 65 is near-spherical and inflatable, to be as compatible as possible with the shape of the belt in the contact area (see Figures 3 and 3a) and with the belt fabric. The drive to the belt is once again taken preferably from the roller 54 upstream of the hopper 37, if necessary with the assistance of a nip or snubbing roller (not shown).

The return roller 67 at the delivery end of the elevator is shown to be mounted parallel to the feed roller spindle, and its distance upstream of the end of the tubular section 52 is variable, to minimise, if necessary, the formation of a "pocket" where the belt flattens out. A pocket (69) as shown, requires precautions to prevent material falling back down the slope. Shown in full and broken lines is spring loaded or resilient plate 71 covering the pocket and a secondary, belt-driven assister roller 73 above the return roller 67. The further upstream the return roller is moved the less pronounced becomes the effect of the pocket 69.

Delivery of the conveyed material to one side or the other can be achieved by mounting the return roller so that it operates inclined in either direction up to the vertical. The belt 63 will the be smoothly twisted through 90" within the tube 52, and the return run will be essentially like that shown in the side view in Figure 2.

To prevent the relatively wide belt 63 from being in frictional contact with too large a percentage of the internal surface area of the tube 52, inserts are preferably provided within the tube to lift the belt clear of much of the inner tube wall. One such arrangement is shown in the cross-section of Figure 3b where the inserts 66 comprise three half-round lengths of wood or other material simply attached to the inside of the tubular member as shown. Figure 3c is a sectional plan view of the tube shown in Figure 3b with the belt absent. Figure 3dshows another form of belt-lifting additions or inserts 66.

As well as the parallel and spiral configurations shown in the drawings, the inserts 66 may be serpentine, converging, diverging or of other composite regular or irregular shapes. In all cases, however, it is desirable that contact between the inserts and the belt be confined to line or, at most, narrow strip contact, in heavy load applications and that contact with the belt should change laterally along the length of the belt so as not to concentrate belt wear. it is also important that no problem of belt tracking shouid be created by the inserts. It is even possible, where the belt is required to twist in a pronounced manner within a tubular shroud, e.g. as in the embodiment of Figure 4thatthe inserts may be used to assist in achieving this.

Although the contact-reducing protrusions on the internal surface or surfaces of the shrouds are referred to as inserts, they may of course be cast, moulded, folded, pressed or otherwise formed during the manufacturing or fabrication process.

Figures 3eto 3h illustrate alternative crosssections of ducting which may be used in place of the circular-section tube 52 to guide a single belt or indeed twin belts. Another alternative is that shown in Figure 2f.

A common advantage of the alternative duct sections is the relatively low contact area between belt fabric and duct walls.

A most convenient way of varying crop delivery laterally through an arc is to provide a swivel ring near the centre of a circular section tube, as shown at 75, so that the upper section 77 may be turned relative to the lower section 78 about its longitudinal axis for example by a rack and pinion mechanism, as shown, or by remote cable or electric, pneumatic or hydraulic controls. This permits the geometry and relative positions of components in the delivery area to be maintained. However, it will be necessary to arrange for the spring loading of both ends of the return roller spindle 80, to accommodate the shortening of one edge of the belt as the belt is twisted within the tube.

The swivel collar is also a convenient means for reducing the height of the elevator for transportation. By first pivoting the elevator so that the tube 61 lies within easy reach of the operator on the ground and slackening the belt 63, the upper half 77 of the tube may be withdrawn and folded over into a suitable attitude in which it can be held by conveniently placed support brackets (not shown). More sophisticated ways of folding the tube are possible, using hydraulic rams or cables.

A convenient method of urging the bend-forming roller or rollers onto the belt or belts of the second and third embodiments is shown in Figure 3i.

Appropriately handed torsion springs 82 over the sprigots 84 serving as pivots for the roller arms 44, 45 may be wound up until the required downward pressure is obtained.

In Figure 4 is shown a single-belt elevator similar to that described in Figure 3, except that the belt 88 is turned through up to 1800 during its passage through the tube. In consequence the return run of the belt has to be above the tube 78. It may be made to take different paths, as shown by the alternative full and broken outlines 90, 91. An essential requirement is that sufficient clearance is provided above the hopper 37 in order not to restrict feeding the material on to the belt.

At the delivery end, a light-weight, e.g. plastic moulded, impeller rotor 93 is shown which accelerates the crop so that it is thrown a sufficient distance to fill trailers in the rear-loading mode. The rotor is driven by one crossed belt 95, or one on each side, from the return roller 67. To gain sufficient traction, the wrap of the return roller may need to be increased by a secondary nip or snubbing roller (not shown). A deflector or enclosed chute (not shown) above the impeller rotor 93 helps to direct the material in a compact stream in to the trailer or container.

Figure 5 shows a suitable tube support frame 97 for the belt-shrouding tubes of Figures 1 to 4 (here identified by reference numeral 99).

Turning now to the principal dimensions and data of the various embodiments described above, the following are given as a guide and are not to be taken as limiting application or design: maximum cross-sectional tube dimension 1 00mm for freeflowing materials to 400mm for coarse and fibrous materials and small packages; diameter of bendforming roller 120 to 500mm; preferred shape of bend-forming roller: spherical; width of belt for twin-belt systems 0.7 to 1.3 x the maximum crosssectional tube dimension; width of belt for singlebelt systems 1.2 to 3.1 x maximum cross-sectional tube dimension; belt speed 1 to lOmis; preferred belt speed 2 to 6m/s; most preferred belt speed 4m/s; drive roller diameter 80 to 250mm; diameter of delivery enhancing impeller rotor 0.8 to 1.5 x maximum cross-sectional tube dimension; peripheral speed of impeller rotor 6 to 1 2m/s.

A single bend-forming roller is usually adequate for inclinations of up to 60 of the tube relative to the plane of the feed conveyor section. At steeper angles a more gradual transition becomes desirable, requiring two or more bend-forming rollers in tandem, with more than two preferably attached to a curved and pivoted bogey. Examples of this latter arrangement are given in co-pending UK Patent Application 8217554.

In single belt elevator configurations according to the present invention, if variable loads are to be expected as a result of the material being conveyed tending to cling together e.g. as with forage crops, a simple means of preventing uneven conveying and delivery is to provide suitably hinged stops at the top end of the constraint member. These stops can, for example, consist of strips of material so hinged to the constraint member or to an appropriate mounting member that they can pivot downwardly only as far as the position in which they are perpendicular to the longitudinal axis of the constraint member whereas they can pivot upwardly, due to the force exerted on them by the crop or other material being conveyed, if necessary to the point at which they lie parallel with the longitudinal axis of the constraint member.

CLAIMS (Filed on 1 Feb 1983) 1. A shrouded belt elevator comprising one or more belts and means for shaping and/or constraining the elevating region of the belt or belts into a load-holding configuration.

2. A shrouded belt elevator comprising two belts, the load-engaging runs of which are adapted to move within and be constrained by a tube or trough-like constraint member.

3. An elevator as claimed in Claim 2 in which the load-engaging runs of the two belts are inclined to one another in a V-form configuration at the intake end of the constraint member.

4. An elevator as claimed in Claim 3 in which at the delivery end of the constraint member, the load-engaging runs of the two belts are parallel to one another.

5. An elevator as claimed in Claim 3 in which at the delivery end of the constraint member, the load-engaging runs of the two belts are disposed in a V-form or inverted V-form configuration.

6. An elevator as claimed in any of Claims 2 to 5 in which the relative inclinations of the loadengaging runs vary along the length of the constraint member and the two belts pass at the delivery end of the constraint member about two roller-type supports inclined lengthwise of the constraint member to compensate for the effect of this varying belt inclination and to encourage equal tension at both edges of the two belts.

7. An elevator as claimed in any preceding claim in which the load-engaging runs of the two belts are everywhere spaced apart whereby the drive means is adaped for optionally driving the two belts at different relative speeds thereby to enable the load to be discharged at different lateral trajectories at the delivery end of the elevator and/or to achieve a rolling and compacting effect on the load during its passage through the constraint member.

8. A shrouded belt elevator as claimed in any preceding claim comprising one or more belts having, or each having, its operative run divided into a load-accepting section and a shrouded loadelevating section by belt-shaping means contoured to shape the belt or belts into a load-embracing configuration.

9. An elevator as claimed in Claim 8 in which there are two such belts with the load-engaging runs of the two belts run flat side by side in the load-accepting section of the elevator and suitably shaped longitudinally and transversely in the concave transition region leading to the shrouded load-elevating section by a bed-plate underneath the belts and by an appropriately shaped roller means above the belts.

10. An elevator as claimed in Claim 9 in which the roller means take the form of a single central, downwardly-sprung roller, pneumatic wheel or sphere or it takes the form of two rollers, pneumatic wheels or hemospheres arranged side by side, one on each belt.

11. An elevator as claimed in Claim 10 or Claim 11 in which the load-engaging runs of the two belts are disposed horizontally or near-horizontally in the load-accepting region.

12. A shouded belt elevator as claimed in Claim 8 when including the limitations of Claim 2 in which there is a single wide belt shaped at the intake end of the constraint member so as to at least in part embrace the load on entering the constraint member.

13. An elevator as claimed in Claim 12 in which the belt is suitably shaped for its passage through the constraint member by one or more springloaded shaping rollers or roller assemblies arranged at the intake end of the constraint member.

14. An elevator as claimed in Claim 13 in which the or each roller is a hard roller with or without a resilient covering.

15. An elevator as claimed in Claim 13 in which the belt is suitably shaped for its passage through the constraint member by an inflated pneumatic wheel or wheels.

16. An elevator as claimed in Claim 15 in which the or at least one of the wheels is of spherical or near-spherical shape.

17. An elevator as claimed in Claim 13 in which the belt is suitably shaped for its passage through the constraint member by an inflated pneumatic roller or rollers.

18. An elevator as claimed in any preceding claim in which the width of the belt is significantly greater than the largest cross-sectional dimension of the constraint member.

19. An elevator as claimed in any preceding claim in which, at the delivery end of the constraint member, the conveying belt is guided into the return run by a direction-changing delivery roller whose position is adjustable to minimise the formation of a pocket by the belt in the delivery region.

20. An elevator as claimed in any preceding claim in which at the delivery end of the constraint member the delivery roller axis is rotatable to encourage delivery of the belt-engaged load to one or other side of the elevator.

21. An elevator as claimed in any of Claims 2 to 19 in which the constraint member is a multi-part

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. with more than two preferably attached to a curved and pivoted bogey. Examples of this latter arrangement are given in co-pending UK Patent Application 8217554. In single belt elevator configurations according to the present invention, if variable loads are to be expected as a result of the material being conveyed tending to cling together e.g. as with forage crops, a simple means of preventing uneven conveying and delivery is to provide suitably hinged stops at the top end of the constraint member. These stops can, for example, consist of strips of material so hinged to the constraint member or to an appropriate mounting member that they can pivot downwardly only as far as the position in which they are perpendicular to the longitudinal axis of the constraint member whereas they can pivot upwardly, due to the force exerted on them by the crop or other material being conveyed, if necessary to the point at which they lie parallel with the longitudinal axis of the constraint member. CLAIMS (Filed on 1 Feb 1983)

1. A shrouded belt elevator comprising one or more belts and means for shaping and/or constraining the elevating region of the belt or belts into a load-holding configuration.

constraint member with at least one part able to swivel sideways relative to the adjacent part or parts about the longitudinal axis of the constraint member.

22. An elevator as claimed in Claim 21 in which the delivery roller spindle is spring-loaded so as to be able to accommodate shortening of one edge of the belt when the delivery roller axis along or the constraint member is swivelled.

23. An elevator as claimed in any preceding claim when comprising only a single loadembracing belt in which the belt is twisted through up to 1800 during its passage through the constraint member.

24. An elevator as claimed in any preceding claim in which the constraint member is of circular or part-circular cross-section, or of square or rectangular-section or other polygonal section.

25. An elevator as claimed in Claim 24 when the constraint member is of circular or part-circular cross-section, including inserts provided within the constraint member to lift the belt clear of much of the inner wall of the constraint member thereby to reduce the frictional forces exerted on the belt.

26. An elevator as claimed in any preceding claim in which the frictional forces exerted in the belt are reduced, or further reduced, by having the shroud-engaging surface of the belt or belts transversely or longitudinally rubbed or corrugated.

27. An elevator as claimed in any preceding claim in which the belt or belts are guided to form a horizontal or near-horizontal load-accepting region prior to entry into the constraint member.

28. An elevator as claimed in Claim 27 in which the drive means for the belt or belts is provided upstream of the load-accepting section so that the belt or belts are pushed towards the concave transition region and into the constraint member.

29. An elevator as claimed in any preceding claim in which in-work changes in inclination of the constaint member may be effected to vary the delivery point of the elevator.

30. An elevator as claimed in any preceding claim in which adjustment means are provided at the intake end of the constraint member for varying the pressure exerted on the belt or belts by the springloaded, bend-forming, rollers, wheels or spheres or the like.

31. An elevator as claimed in any preceding claim in which an impeller rotor is provided at the delivery end of the constraint member to accelerate the load and allow its discharge into a container relatively remote from the delivery end of the elevator.

32. An elevator as claimed in any preceding claim in which the gripping capacity of the loadembracing belts is enhanced by having the loadengaging surface transversely ribbed or corrugated.

33. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figures 1 and la of the accompanying drawings.

34. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figures 2, 2a, 2b, and 2d of the accompanying drawings.

35. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 2c of the accompanying drawings.

36. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 2e of the accompanying drawings.

37. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 2f of the accompanying drawings.

38. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figures 3 and 3a of the accompanying drawings.

39. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figures and 3e of the accompanying drawings.

40. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 3d of the accompanying drawings.

41. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 3e of the accompanying drawings.

42. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 3f of the accompanying drawings.

43. An elevator substantialy as hereinbefore described with reference to and/or as illustrated in Figure 3g of the accompanying drawings.

44. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 3h of the accompanying drawings.

45. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 3i of the accompanying drawings.

46. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 4 of the accompanying drawings.

47. An elevator substantially as hereinbefore described with reference to and/or as illustrated in Figure 5 of the accompanying drawings.