This invention is concerned with distributing particulate material.

In various industries, the requirement exists to distribute particulate material held in a box so that the material has a predetermined distribution within the box. In the simplest case, the material is distributed so that it has a constant depth throughout the area of the box but other distributions may be required. For example, a greater depth may be required at one or more edges of the box than is required in the centre thereof.

In GB patent Application No. 2 275 223, there is described a method and an apparatus for charging a cavity with particulate material. The material is positioned in a box which is closed at the bottom by a door, the box is moved to and fro horizontally a plurality of times to give the particulate material an even distribution in the box, and the door is removed sufficiently rapidly that the material falls into a cavity substantially as a unit. The apparatus described is arranged to move the box horizontally successively in two perpendicular directions which extend longitudinally and transversely of the box (which is generally rectangular in plan view) . The apparatus has two motors each of which is operable to cause movement in one of said directions.

It is an object of the present invention to provide an apparatus and a method whereby particulate material can, in some circumstances, be given a predetermined distribution more effectively than is the case with the apparatus and method of GB 2 275 223.

The invention provides apparatus for use in giving particulate material in a box a predetermined distribution, the apparatus comprising a support for a box, characterised in that the apparatus also comprises mounting means for said support which constrains the support to move in a horizontal plane along a substantially circular path with the box retaining a constant orientation, and moving means operable to bring about controlled movements of the support and of a box mounted thereon, the moving means being operable in a continuous manner to cause the support and a box mounted thereon to move around said path or in an oscillatory manner to cause the support and a box mounted thereon to move back and forth along an arc of said path.

An apparatus according to the invention is capable of shaking a box in a wide range of ways to give many possible distributions. For example, the box can be given a circular shake, and shakes which are effectively longitudinal, transverse, or diagonal relative to the box can be achieved by shaking along selected arcs. Successive arcuate and circular shakes can be combined in many ways.

The mounting means preferably comprises a first drive shaft, and a second drive shaft, the drive shafts extending vertically and being arranged to be turned in synchronisation about their respective longitudinal axes, the mounting means also comprising a first crank arm fixedly-mounted on the first drive shaft and projecting radially therefrom, and a second crank arm fixedly-mounted on the second drive shaft and projecting radially therefrom, the crank arms extending parallel to one another and each being pivotally connected to the support, the distance between the longitudinal axis of the drive shaft associated with each crank arm and its pivotal connection with the support being substantially the same for both crank arms.

In order to increase accuracy, the moving means may be operable to drive the drive shafts through a reduction gear system.

In order to assist loading and unloading of the box, apparatus according to the invention may be mounted for movement by lifting means operable to raise or lower the apparatus and hence a box mounted on the support.

The invention also provides a method of giving particulate material in a box a predetermined distribution, the method comprising mounting the box on a support, characterised in that the method also comprises operating moving means to bring about controlled movements of the support and of the box while retaining the orientation of the box constant, the controlled movements comprising a first movement in which the box is moved around a horizontal path which is substantially circular, and a second movement in which the box is moved back and forth along an arc of said path.

In a method in accordance with the invention, particulate material can be given an initial distribution by said first movement and brought to said predetermined distribution by said second movement. For some types of particulate material and/or for some shapes of box, a method according to the invention is found to be more effective than linear movements in one or two perpendicular directions. Furthermore, since arcuate movements can be achieved by making oscillatory movements along part of a circular path, the method can be carried out using only one motor.

The controlled movements may also comprise a third movement in which the box is moved back and forth along a different arc of said path, said circular arcs being displaced angularly, eg their centres may be displaced by

90°. The second movement may be generally longitudinal of a generally rectangular or elongated box and the third movement may be generally transverse thereof. In this way, the particulate material can be distributed both along and across the box. By using arcs of the circular path, used in the first movement, in the second and third movements, the arcs being centred 90° apart, all three movements can be achieved with one motor.

The second and any third movement may have a frequency of 1 to 3 Hertz. The or each arc may subtend up to 120°. For example, the second movement may be at a frequency of 2 Hertz and involve back and forth movement through 120° centred on a line extending transversely of the box and the third movement may be at the same frequency and involve back and forth movement through 80° centred on a line extending longitudinally of the box.

There now follow detailed descriptions, to be read with reference to the accompanying drawings, of an apparatus for giving particulate material in a box a predetermined distribution which is illustrative of the invention and of a method of utilising the illustrative apparatus which is illustrative of the method aspects of the invention.

In the drawings:

Figure 1 is a side elevational view of the illustrative apparatus;

Figure 2 is a front elevational view of the apparatus shown in Figure 1 showing a box in position on a support of the apparatus; and

Figure 3 is an underneath view taken in the direction of the arrow III in Figure 2 of the support of the illustrative apparatus.

The illustrative apparatus is for use in giving particulate material in a box 10 a predetermined distribution. The box 10 is generally rectangular in plan view and has a side flange 10a which defines two vertical bores 11 which have openings in a lower surface 10b of the flange 10a. The box 10 may be of the type described in GB 2 275 223 A which is equipped with two horizontal bottom doors which can be opened rapidly to allow particulate material, in its predetermined distribution, to fall as a unit away from the box. Alternatively, however, the box 10 may have only one bottom door and the or each bottom door may not be horizontal but may be inclined to give the box different depths at different points therein. The predetermined distribution may result in the particulate material being evenly distributed in the box 10 or may result in greater concentrations in a certain part or parts of the box 10. The particulate material may comprise a mixture of several different materials which may have different particle sizes. For example, the particulate material may comprise a mixture of particles some of which may be of metal, eg short lengths of wire.

The illustrative apparatus comprises a support 12 for the box 10. The support 12 is in the form of a horizontally-extending plate which is generally rectangular except that it has increased width near one end (see Figure 3) . Two cylindrical columns 12a and 12b project upwardly from the support 12 in the portion thereof of increased width.

The illustrative apparatus also comprises mounting means 14 for the support 12. The mounting means 14 constrains the support 12 and a box 10 mounted thereon to

move in a horizontal plane which is the plane of the plate forming the support 12. Specifically, the mounting means 14 constrains the support 12 and the box 10 to move along a circular path in said plane with the box 10 retaining a constant orientation, ie the box 10 does not rotate as it moves along the circular path.

The illustrative apparatus also comprises an electrical servo-motor 16 which provides moving means operable to bring about controlled movements of the support 12 and of a box 10 mounted thereon.

The mounting means 14 comprises a first drive shaft 18, and a second drive shaft 20. The drive shafts 18 and 20 extend vertically and are arranged to be turned in synchronisation about their respective longitudinal axes by operation of the motor 16. The mounting means 14 also comprises a first crank arm 22 fixedly-mounted on the first drive shaft 18 and projecting radially therefrom, and a second crank arm 24 fixedly-mounted on the second drive shaft 20 and projecting radially therefrom. The crank arms 22 and 24 extend horizontally parallel to one another and both are pivotally connected to the support 12. The crank arms 22 and 24 are each pivotally connected to the support 12 with the distance between the longitudinal axis of the associated drive shaft 18 or 20 and the pivotal connection with the support 12 being the same for both crank arms 22 and 24. Operation of the motor 16 turns both the shafts 18 and 20, turning both crank arms 22 and 24 together and moving the support 12 arcuately in the plane of the support while retaining the orientation of the box 10 constant. The arrangement, thus, is such that operation of the motor 16 causes motion of the support 12 and of a box 10 mounted thereon in a horizontal plane, the motion being rotary around said circular path, when operation of the motor 16 is in a continuous manner, and being back and forth along

a circular arc of said path, when operation of the motor is in an oscillatory manner.

The motor 16 is mounted in a vertical orientation on a carrier 30 with an output shaft (not shown) of the motor 16 projecting downwardly. The carrier 30 (and hence the remainder of the illustrative apparatus) is mounted for vertical movement on a fixed frame 34, the frame 34 carrying linear bearings 36 on which a vertical rail 38 secured to the carrier 30 slides. The frame 34 also supports a vertically-disposed air cylinder 40 which has a piston rod 42 secured to the rail 38 by means of a bracket 44. The cylinder 40 provides lifting means operable to move the illustrative apparatus and hence a box 10 mounted on the support 12. Specifically, the cylinder 40 is operated to raise the box 10 to a receiving position, at which particulate material can be delivered to the box 10 from a hopper, and to lower the box 10 to a delivering position at which the distributed material can be dropped out of the box 10.

The carrier 30 is hollow and contains bearings 48 on which the drive shafts 18 and 20 are mounted. Also within the carrier 30, each of the drive shafts 18 and 20 carries a gear 47. These gears 47 are within and mesh with a ring gear 46 so that, when the gear 46 turns, the gears 47 and, hence the drive shafts 18 and 20, both turn in the same sense. The motor 16 operates through a reduction gearbox 16a to turn an output shaft 49 on which a further gear 49a is mounted. Operation of the motor 16 turns the gear 49a which turns the gear 46 thereby turning the gears 47 and the two drive shafts 18 and 20 in synchronisation, ie through the same angles and in the same sense. The reduction gearbox 16a steps down the rotation, in this case by 5:1, so that the drive shafts 18 and 20 turn more slowly than the motor 16. This arrangement increases accuracy.

The drive shafts 18 and 20 extend downwardly beyond the carrier 30 where they carry the crank arms 22 and 24. Each crank arm 22 and 24 is connected to the support 12 by means of a pivot pin 50 and 52, respectively. The pins 50 and 52 are located at equal distances from the longitudinal axes of the drive shafts 18 and 20, respectively. The pins 50 and 52 are fixed to the arms 22 and 24 and are mounted for rotation on bearings 54 mounted on the support 12.

Operation of the motor 16 causes the crank arm 22 to be turned about the longitudinal axis of the drive shaft 18 so that the pin 50 moves in a circle around said longitudinal axis. The movement of the pin 50 causes movement of the support 12 and of the box 10. Because the pin 52 is performing an identical movement about the longitudinal axis of the shaft 20, the orientation of the support 12 remains constant, since a line joining the pins 50 and 52 always points in the same direction.

In the illustrative method, the box 10 is first mounted on the support 12. To mount the box 10 on the support 12, the box 10 is lowered so that the two upwardly- projecting columns 12a and 12b enter the bores 11. The lowering continues until the lower surface 10b of the flange 10a rests on an upper surface 12c of the support 12. The columns 12a and 12b are close fits in the bores 11 so that the box 10, once mounted, cannot move horizontally relative to the support 12 but can easily be removed therefrom by lifting.

The illustrative method continues by introducing particulate material into the box 10 and operating the motor 16 of the illustrative apparatus to bring about controlled movements of the support 12 and of the box 10 in a horizontal plane while retaining the orientation of the box 10 constant, thereby giving the particulate material a predetermined distribution. The controlled movements

comprise a first movement in which the box 10 is moved around said horizontal circular path. The first movement comprises rotary movement at 250 rpm which is maintained for 2 revolutions around the circular path followed by a controlled deceleration to rest over 4 revolutions. The controlled movements also comprise a second movement which follows immediately after the first movement. In the second movement, the box 10 is moved, in an oscillatory manner, back and forth along a horizontal circular arc of the circular path at a frequency of 3 Hertz. The circular arc extends 60° on either side of a line which extends transversely of the box 10, ie the movement is primarily longitudinally of the box 10. The second movement is immediately followed by a third movement. In the third movement, the box 10 is moved in an oscillatory manner, back and forth along a further horizontal circular arc of the circular path at a frequency of 3 Hertz. The further arc extends 40° on either side of a line which extends longitudinally of the box 10, ie the movement is primarily transversely of the box 10. The circular arcs are parts of the circular path.