IES73435B2 - A machine for mixing and discharging materials - Google Patents

Description

The present invention relates to a machine for mixing and discharging materials such as animal feed-stuffs. In particular the invention relates to a machine which may be mounted on an agricultural tractor.

Traditionally animal feed-stuffs which comprise a number of different constituents e.g. beef nuts, rolled barley etc. are either mixed by a farmer himself or bought in bulk ready mixed. Ready mixed products do not allow easy alteration of the mixture ratio. Also it may be desired to store the products separately. The traditional method of mixing animal feed-stuffs on a farm has been to place the materials which comprise the animal feed-stuff in a single feeder or trough one on top of the other.

However this is not a very satisfactory method of mixing food-stuffs as it is difficult to control the proportions mixed. Each animal does not receive the same amount of each ingredient of the food-stuff. 1751S S?3 4 3 5 - 2 GB 2,251,177 A, describes a machine for cleaning and chopping an animal feed-stuff, particularly root crops such as sugar-beet, and which comprises a hopper adapted to receive the beet, a rotor mounted therein supporting a tumbler bar or bars defining a scroll or helix about the rotor and adapted to sweep close to the hopper when revolved by the rotor, so as to agitate and turn over the beet in the hopper to remove adhering dirt and to convey the cleaned beet to a chopper arrangement located to one side of the hopper. An intermediate chamber be be provided between the hopper and the chopper arrangement comprising an auger screw conveyor to feed the chopper with beet when the flap is opened to allow communication with the hopper.

Devices such as augers can be used to convey, and to a certain extent mix, materials from a hopper.

An auger however is usually used to convey materials in a given direction (usually one fixed direction). The direction of conveyance is determined by the direction of the axial rotation of the auger.

While some mixing may occur of materials conveyed by an auger the primary purpose of the auger is to convey the materials only. In order to increase the mixing effect of an auger it may be possible to provide a stop at the discharging end of the auger. This however causes a build up of material on the auger as it is conveyed from the intake end down towards the discharge end. As the material has no means of being discharged it is retained between the stop and the auger and tends to build up there. The continued operation of the auger increases the amount of material building up at the discharge end of the auger and eventually the material may become so compacted or the load on the auger may become so great so as to stop and/or break the auger.

Other methods of mixing are known which involve rotation of a mixing element about a horizontal or vertical axis. Conventional mixing elements do not provide conveyance means for discharging the material once mixed thoroughly.

It is an object of this invention to provide a machine which may be used to both mix and convey material. - 3 Summary of the Invention The invention relates to a machine for mixing and discharging materials comprising a hopper and an auger, the auger being rotatable about a shaft and comprising a ribbon type auger which comprises a ribbon having a helical configuration about the shaft and means for attaching the ribbon to the shaft characterised in that the auger comprises at least one material contact means which extends axially along and in close proximity to at least a part of the ribbon so as to reduce the axial conveying effect of the auger when rotated. Suitably the or each material contact means is disposed parallel to the shaft and abuts or is in close proximity to the inner edge of the ribbon. This arrangement increases the mixing effect of that part of the auger along which the material contact means extend. Preferably the means for attaching the ribbon to the shaft comprises a series of spokes.

In a preferred embodiment the or each material contact means defines a transverse flap which is displaceable between a position proximate to the ribbon so as to reduce the axial conveying effect of the auger and an extended position in which position the or each material contact means does not substantially reduce the axial conveying effect of the auger when rotated. In this extended position the mixing effect of the or each material contact means is substantially reduced.

In a preferred arrangement the material contact means is operable to reduce the axial conveying of material when the augur is rotated in one direction, and the material contact means becomes inoperable such as not to substantially reduce the axial conveying of material when the augur is rotated in the opposite direction. For example, the or each material contact means automatically adopts the proximate position when the auger is rotated in one direction and adopts the extended position when the auger is rotated in an opposite direction. This may be achieved by allowing the or each material contact means to pivot about a hinge arranged so that when the auger is rotated in one direction the or each material contact means engages against at least one spoke, and when rotated in the other direction is disengaged from this position. - 4 The pressure of the material being mixed may be used to cause these positions to be assumed alternately. Suitably a stop is provided which ensures that the or each material contact means returns to the engaged position proximate the ribbon from the extended position when the direction of rotation is reversed, thus preventing the or each material contact means flipping over to an angle of 180° to the desired position.

Suitably the or each material contact means extends along part of the metal ribbon thus defining a mixing section of the auger. Suitably the material contact means defines a bar or flap.

In a more preferred embodiment the auger further comprises a discharge section defined by a double helical ribbon in addition to the mixing section. The double helical ribbon may be provided by locating a second partial helical shaped ribbon at the discharge end of the auger.

The invention extends to a machine substantially as herein described with reference to and as illustrated in the accompanying drawings.

Brief Description of the Drawings Figure lisa cross-sectional view of the machine of the invention.

Figure 2 is a top view of the device of Figure 1 and Figure 3 is a side view of the auger incorporated in the device of the invention.

Figure 4 is an end view of the auger of Figure 3.

Detailed Description of the Preferred Embodiment The machine of the invention will now be described with reference to Figures 1 to 4.

With reference to Figure 1 the machine 1 includes a hopper 2 which consists of casing 3. An auger 4 is splined on a shaft 5 mounted in casing 3 and which transverses the hopper 2. The auger 4 is located adjacent the bottom of the hopper 2. - 5 As is customary the hopper 2 is shaped conventionally so as to direct any material placed therein onto the auger 4. The auger 4 is mounted so as to come into close contact with but not abut the base and side walls of hopper 2. The hopper 2 has a part circular profile 6 along its bottom wall which matches the profile of the auger 4.

An upper or top link point is provided by bracket 6 while a lower link point is provided by brackets 7. Both bracket 6 and 7 are located on the casing 3 of the hopper 2. These brackets provide attachment points for the three point linkage (front or rear) of a conventional agricultural tractor or may be used to fit the machine 1 to a front loader.

The auger 4 is driven by a hydraulic motor (not shown) which may be operated from the hydraulic fluid system of an agricultural tractor. The rotation of auger 4 can thus be reversed as is allowed by conventional hydraulic motors by reversing the direction of flow of the hydraulic fluid through the motor.

With reference to Figure 2 the auger 4 is shown in more detail. Shaft 5 is mounted in hopper 2 one end each in housing 8 and 9. The end of the shaft 5 which is located in housing 9 is the end of the shaft which is driven by the hydraulic motor (not shown). The auger shown is a ribbon type auger i.e. a flat bar (suitably 50mm x 10mm 40mm x 12mm in cross section) or ribbon of metal 10 is profiled about shaft 5 in a spiral shape and being held in place by spokes 11 which project radially outwardly from and substantially perpendicular to the shaft 5. The ribbon 10 defines a helical configuration about shaft 5. The auger 4 thus has an open configuration i.e. the space between the flat metal ribbon 10 and the shaft 5 is not filled in. Conventional augers which are used mainly for conveying materials have a closed profile whereby a flat metal sheet is helically spiraled about the shaft 5 so as to provide a continuous blade which extends from the shaft 5 to the outer edge of the auger 4. Augers having an open profile are also known but are not used as widely.

As can be seen from Figure 2 the auger 4 has two distinct sections: a discharge section 12 comprising a double helix comprising - 6 ribbon 10 and a second ribbon 19; and a mixing section 13 which comprises a single ribbon 10. A discharge gate or flap (not shown) is located on end wall 14 or hopper 2. This gate or flap is opened when it is required to discharge the material in the mixer while it is retained in the closed position while the material is being mixed before discharging. The ratio of the length of the mixing section to that of the discharge section is approximately 2:1.

With reference to Figures 3 and 4 the auger 4 will now be described. The auger 4 has three transverse flaps or bars 15 which are attached by hinges or pivots 16 each to two spokes 11. From the perspective of Figure 4 it can be seen that each consecutive spoke 11 is arranged at an angle of approximately 120° from that of the previous spoke. Every third spoke 11 is thus substantially aligned with the first.

The transverse flaps 15 are pivotable between an engaged position substantially abutting spoke 11 and an extended position (shown in dotted outline in Figures 1 and 4). As can be seen from Figures 1 to 4 the tops 17 of the transverse flap 15 are in close proximity to the inner edge 18 of the auger 4.

From the perspective of Figures 1 and 4 when the auger 4 is rotated in a clockwise direction the transverse flaps 15 are forced into the engaged position, abutting spokes 11, by the material being mixed. The presence of transverse flaps 15 reduce the conveying effect of the auger 4 by forcing material which would normally travel along the ribbon 10 of the auger across ribbon 10. This increases the rotational movement (mixing effect) of the auger while reducing the axial conveying effect. The transverse flaps 15 extend only along the single ribbon helix of the mixing section 13.

When the direction of the auger is reversed by reversing the flow of hydraulic fluid through the hydraulic motor the transverse flaps 15 are forced into the extended position by the material being mixed. In this position they are a substantial distance away from the inner edge 18 of the ribbon 10 and thus do not interfere with the conveyance effect of the auger 4. The flaps 15 trail through the material. Since - 7 the flaps 15 present a narrow edge to the material they generate very little rotational movement. The auger thus has two substantially different functions i.e. mixing or conveyance depending on the direction of rotation of the auger. As flaps 15 are freely pivotable between these two positions and assume these positions automatically when the direction of rotation is reversed then control of the direction of rotation of the auger 4 determines the function of the machine 1. It will be appreciated that while the freely pivotable arrangement is preferred it is possible to provide a mechanism which controls the position of the flaps 15 independently of the direction of rotation.

While the transverse bars or flaps do not completely eliminate the build-up of material in the hopper 2 at the discharge end of the auger 4 (when the auger is rotated in a clockwise direction) it substantially reduces such build-up and mixing of the material can be carried on indefinitely without fear of the auger becoming blocked from such a build-up. When the material is sufficiently mixed, the direction of the auger is then reversed, the flaps assume the extended position as they are free to pivot about hinges 16 and the auger 4 has a much increased capacity for conveyance and conveys the material at a much greater rate towards the discharge end (auger rotating in anti-clockwise direction) than it did when the direction was reversed. The rotational movement of the material is substantially reduced in the discharge mode.

As the flaps 15 are freely pivotable it is preferred that when in an extended position they define a maximum angle with a spoke 11 to which they are attached which ensures the flap will return to the engaged position in close proximity to the ribbon 10 and not flip over to a position at 180° to this desired position. In this regard a stop (not shown) may be provided which restricts each flap 15 to the required amount of angular movement.

As the rotational speed of augers tend to be conventionally relatively slow the discharge from the machine 1 may be quite slow.

This may be improved by speeding up the rotation rate of the auger and/or varying the size of the discharge gate or flap on side wall 14. - 8 These may be achieved respectively by varying the hydraulic oil supply from the tractor to the hydraulic drive motor and the size of the discharge opening e.g. by a hydraulically operated guillotine door.

While varying the above two parameters may increase the discharge rate of the auger the discharge still tends to be pulsed in that the material is not discharged at a constant or even rate. This is in part due to the relatively slow rate of rotation of the auger 4 and its relatively large diameter. The normal pulsed discharge is overcome by discharge section 12 of the auger 4 which has provided a second metal ribbon section 19 which is attached to the discharge end of shaft 6 so as to provide a double helical configuration. This extra ribbon 19 does not substantially effect the build-up of material during mixing as in any case such build-up would tend to occur at the opposite drive end of the shaft 5. A two fold effect is thus achieved by the auger 4 of the invention by providing the double helix discharge section 12 together with the pivotable transverse flaps 15 which allow the conveyance capacity of the auger to be increased by moving into the extended position during the discharge mode of the machine 1. The pulsed discharge is evened out by extra ribbon 19, which gives an extra discharge pulse on each revolution of the auger. The discharge rate is maintained at a high level even towards the end of the load of the material being discharged, and remains at the high level even if the material being discharged is quite wet.

Fixed bars may be used instead of flaps 15 but these may result in the discharge rate of the machine being quite low, especially towards the end of the load. Fixed bars will however give the desired mixing effect.

Claims (5)

1. A machine (1) for mixing and discharging materials comprising a hopper (2) and an auger (4), the auger (4) being rotatable about a shaft (5) and comprising a ribbon type auger which comprises a ribbon (10) having a helical configuration about the shaft (5) and means (4) for attaching the ribbon (10) to the shaft (5) characterised in that the auger (4) comprises at least one material contact means (15) which extends axially along and in close proximity to at least a part of the ribbon (10) so as to reduce the axial conveying of the auger (4) when rotated.

2. A machine according to claim 1 wherein the or each material contact means (15) which is displaceable between a position proximate to the ribbon (10) so as to reduce the axial conveying effect of auger (4) and an extended position from the ribbon (10) in which position the or each material contact means (15) does not substantially reduce the axial conveying effect of the auger when rotated (4).

3. A machine according to claim 2 or 3 wherein the or each material contact means (15) extends along a part of the metal ribbon (10) thus defining a section (13) of the auger (4) with a reduced axial conveying effect and further comprising a discharge section (12) defined by a double helical ribbon (10,19).

4. A machine according to claims 2 or 3 wherein the or each material contact means (15) is freely pivotable between the proximate and extended positions and assumes one of these positions when the auger (4) is rotated in one direction and the other when the direction of rotation of the auger (4) is reversed due to the pressure of the material being mixed.

5. A machine (1) for mixing and discharging materials substantially as described herein with reference to and as illustrated in the accompanying drawings.