Abstract:
The present invention provides a movement output apparatus for controllably moving a movement output means in at least two spatial dimensions, the apparatus including: a cog means with a first diameter; a ring with a track formed on an inner surface of the ring, the track having a second diameter which is larger than the first diameter; wherein: the cog means is rotatable by first driving means; the ring is rotatable by second driving means; the cog means is arranged to move, in use, along the track; and the movement output means is attached to the cog means, whereby, in use, movement of the cog means effects movement of the movement output means, and the movement of the movement output means is controllable by control of the first and second driving means to produce substantially linear movement of the movement output means to produce substantially linear movement of the movement output means.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a movement output apparatus. More particularly, the invention relates to a movement output apparatus for controllably moving a movement output means in a desired shape.  
       BACKGROUND AND SUMMARY OF THE INVENTION  
       [0002]     It is often desirable to move items or parts of machinery to particular positions, those positions being reached with spatial reliability. In particular, it is sometimes desirable to be able reliably to cycle parts of machinery between particular positions. This would be the case, for example, where it is necessary to form a particular shape in a repetitive manner.  
         [0003]     An example of shape forming using machinery is in the food manufacturing and processing industry. Food items such as biscuits often have decorative toppings in particular shapes. For efficiency, throughput and consistency reasons, mechanical deposition systems are often used to deposit such decorative toppings.  
         [0004]     Such mechanical deposition systems may include a moveable deposition manifold arranged on a conveyor belt. The deposition manifold is moveable in the sense that it can be made to describe a particular shape with respect to food items travelling along the conveyor belt. Typically, the deposition manifold is moveable independently of the conveyor belt. The movement of the manifold is powered and controlled by suitable arrangements of linear drives, for example suitable arrangements of ball screws and pulleys.  
         [0005]     More generally, it is often desirable to perform a repetitive process on a series of similar items. Typically, items are transported around a production facility using a conveyor belt or similar means. If the items are relatively small, or if the production line has a large output, the items may be arranged in ranked rows on the conveyor belt.  
         [0006]     Many processes in production lines require that the position of the items to be processed is known with some spatial reliability. Typically, items on a conveyor belt are prone to move a little on the conveyor, due to vibrations etc. Movement apparatus can be used to move the items to a predetermined position on the conveyor, ready for a subsequent processing step. The movement apparatus typically is powered and controlled by suitable arrangements of linear drives, as for the deposition manifold above.  
         [0007]     These arrangements of linear drives are usually bulky and difficult to install or retro-fit to existing production lines. In addition, it is difficult to operate movement of the manifold using such arrangements at speeds necessary for large volume production.  
         [0008]     In order to address the problems outlined above, the present invention provides, in a first aspect, a movement output apparatus for controllably moving a movement output means in at least two spatial dimensions, the apparatus including: 
        a cog means with a first diameter;     a ring with a track formed on or near the surface of the ring, the track having a second diameter which is larger than the first diameter;     wherein:     the cog means is rotatable by first driving means;     the ring is rotatable by second driving means;     the cog means is arranged to move, in use, along the track; and     the movement output means is attached to the cog means whereby, in use, movement of the cog means effects movement of the movement output means, and the movement of the movement output means is controllable by control of the first and second driving means preferably to produce a substantially linear movement of the movement output means.        
 
         [0016]     Using the apparatus, the movement of the movement output means can be controlled to describe a particular two dimensional shape by suitable control of the first and second driving means.  
         [0017]     Preferably, the ring defines a rotation plane and the cog means is preferably rotatable by the first driving means, about a first axis which is typically substantially perpendicular to the rotation plane.  
         [0018]     Preferably, the ring is rotatable by the second driving means about a second axis which is typically substantially perpendicular to the rotation plane.  
         [0019]     Preferably the cog means is rotatable relative to the track about a third axis which is typically substantially perpendicular to the rotation plane. This rotation of the cog means about the third axis is typically brought about due to an interaction between the cog means and the track.  
         [0020]     Preferably, the third axis is substantially parallel to, but typically substantially not co-linear with, the second axis.  
         [0021]     Typically, the cog means and the track each have teeth which are meshable together. Preferably, at least one of the cog means and the track have a substantially circular configuration. More preferably, both the cog means and the track each have a substantially circular configuration.  
         [0022]     In some embodiments, the ring may be replaced by a partial ring. Using such a configuration, the track would preferably be a non-continuous arcuate track.  
         [0023]     In preferred embodiments of the invention, the relationship between the first and second diameters is such that rotation of the cog may cause (possibly in conjunction with rotation of the ring) a point on the cog (usually a point on the perimeter of the cog) to describe a substantially straight line. Preferably, the first diameter is approximately one half of the second diameter. Using such a cog arrangement, the movement output means may be positioned with respect to the cog means such that the movement output means may describe substantially any shape in two dimensions within a particular size range.  
         [0024]     Preferably the movement of the movement output means is controllable to produce linear movement along wither or both of two mutually perpendicular axes. More preferably in use the two axes are respectively substantially horizontal and substantially vertical.  
         [0025]     The movement output means (which may be e.g. a cam follower) may be attached to the cog means such that the centre of the movement output means is a distance from the axis of rotation of the cog means which is substantially equal to the first diameter. In one embodiment, the movement output means is substantially cylindrical and its central axis is substantially parallel to the axis of rotation of the cog means and its central axis is a distance from the axis of rotation of the cog means which is substantially equal to the first diameter.  
         [0026]     Preferably, the cog means is rotatably mounted on a first shaft. Preferably, the first shaft is eccentrically mounted with respect to an output rotation axis of the first drive means. Typically, therefore, operation of the first drive means rotates the first shaft eccentrically. Consequently, the cog is forced to rotatably travel around the track.  
         [0027]     Preferably, the ring and track together form an internal gear.  
         [0028]     Preferably, the output movement means is connected to a movement transmission means.  
         [0029]     Preferably, the apparatus further includes control means for control of the second driving means, the control means operating according to a predetermined set of instructions. Typically, the control means includes a suitably programmed computer. Preferably, the control means controls the first driving means.  
         [0030]     Preferably, the cog means and/or ring are replaceable by a cog means and/or ring of different dimensions in order for the movement output means to controllably describe a shape in two dimensions in a different size range.  
         [0031]     In preferred embodiments, the apparatus further includes a controllable counterbalancing assembly. Typically, such an assembly includes an arrangement of masses which are moveable via one or more driving means. Preferably, the arrangement of masses is moveable in order to substantially reduce vibrations in the apparatus caused by movement of other parts of the apparatus. Preferably, the arrangement movement is controlled by the control means. The arrangement movement may be adapted to be a mirror image movement of the movement of those parts of the apparatus which cause, in use, undesirable vibrations.  
         [0032]     In a second aspect, the present invention provides a repetitive processing apparatus including a movement output apparatus according to the first aspect, and further including a repetitive processing device for repeated performance of a particular process, wherein the repetitive processing device is connected to the movement output means, and in use the position of the repetitive processing device is controllable by control of the position of the movement output means.  
         [0033]     Preferably, the apparatus further includes moveable conveyor means, whereby articles on which a particular process is to be performed are moveable with respect to the apparatus.  
         [0034]     In a third aspect, the present invention provides a deposition apparatus including any apparatus according to the first or the second aspect.  
         [0035]     In a fourth aspect, the present invention provides a foodstuff processing apparatus including any of the features of the second aspect and typically including any features of the third aspect, wherein the repetitive processing device is a foodstuff deposition manifold, the manifold being, in use, controllable to deposit foodstuff in a pre-programmed shape.  
         [0036]     Preferably, the food stuff deposition manifold is capable of performing at least approximately 40 cycles per minute. More preferably, it is capable of performing up to around 100 cycles per minute or more, most preferably up to around 400 cycles per minute or more.  
         [0037]     Preferred embodiments of the invention will now be described, by way of example only, with respect to the accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]      FIG. 1  shows a schematic cross-section of a food processing assembly including an embodiment of the present invention.  
         [0039]      FIG. 2  shows an enlarged view of the portion marked “A” in  FIG. 1 .  
         [0040]      FIG. 3  shows a schematic view of the cog arrangement along the principal axis of shaft  72  in  FIG. 1 .  
         [0041]      FIG. 4  shows a schematic cross-section of a horizontal drive device for the assembly of  FIG. 1  in the same direction as  FIG. 3 .  
         [0042]      FIG. 5  shows a schematic cross-section of a vertical drive for the assembly of  FIG. 1  along the same direction as  FIG. 2 .  
         [0043]      FIG. 6  shows four schematic views of the cog arrangement along the principal axis of shaft  72  in  FIG. 1 , each view showing the cog in a different position relative to the ring.  
         [0044]      FIG. 7  shows an exploded schematic view of the drive shafts, cog, ring and cam follower of  FIG. 1 .  
         [0045]      FIG. 8  shows a schematic view of a counterbalance assembly for suppression of vibration in the main apparatus.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0046]     In  FIG. 1 , the position of a deposition manifold  20  with respect to a conveyor belt  22  is controlled by a control apparatus  24 .  
         [0047]     The control apparatus  24  has a housing  26 . Movement rods  28 ,  30  connect the control apparatus  24  to the deposition manifold  20 . The deposition manifold  20  may also be referred to as the depositing manifold  20 .  
         [0048]     In a typical use, the conveyor belt carries a number of food items, for example individual biscuits, past the deposition manifold. The purpose of the deposition manifold in this example is to deposit a food topping (for example cream, chocolate or jam) onto each biscuit. The deposition manifold may be a pressurised or volumetric manifold, as appropriate.  
         [0049]     Typically, the biscuits are arranged on the conveyor belt  22  in ranked rows. Each biscuit in a particular row reaches the manifold at the same time. On the underside of the manifold there is an array of deposition nozzles (e.g. nozzles  32 ,  34 ), one nozzle per biscuit in a row.  
         [0050]     Careful control of the height of a nozzle over a biscuit is required in order to deposit the correct shape of food topping. In addition, the shape of the food topping on the biscuit is dependent upon the horizontal position of the nozzle during deposition. Furthermore, the horizontal position of the nozzle may be required to (at least on average) keep pace with the conveyor belt during deposition.  
         [0051]     Careful control of both the height and the horizontal position of the manifold can lead to greater uniformity in the shape of the topping on each biscuit. In addition, it can lead to less wastage of topping and biscuits. Typically, the faster the deposition process, the greater the throughput of biscuits.  
         [0052]     After one deposition cycle (i.e. after the manifold has deposited food topping onto one row of biscuits) the manifold is moved back to start the deposition process on the next row of biscuits.  
         [0053]     The position of the manifold  20  is controlled by the control apparatus  24 , via movement rods  28 ,  30 . Rod  28 , for example, can move vertically with respect to the housing  26  due to vertical linear bearings  32 ,  34 . The vertical linear bearings  32 ,  34  are contained in bearing support  36 . The rod  28  and the bearing support  36  can move horizontally with respect to the housing  26  due to horizontal linear bearings  38 ,  40 . Thus, the rod  28  (and, by analogous means, the rod  30 ) is moveable both horizontally and vertically, within predetermined ranges, with respect to the housing  26 .  
         [0054]     As shown more clearly in  FIG. 2 , rod  28  has a cam-receiving attachment  50 . Attachment  50  is fixed with respect to rod  28 . Attachment  50  receives an e.g. cylindrical cam  52 . Movement of cam  52  moves rod  28 .  
         [0055]     Cam  52  is attached to a cog  54 . Cog  54  is rotatably mounted on shaft  56  via bearings  58 . Movement of cog  54  moves cam  52  and hence moves rod  28 . Cog  54  has a plane of rotation which is perpendicular to its principle axis. Cog  54  is constrained to move, in use, substantilly only in this plane. Therefore, cam  52  remains substantially in one plane. Rod  28  has horizontal and vertical linear bearings and so may move in two orthogonal directions, i.e. rod  28  is also constrained to move substantially in one plane with respect to housing  26 ,  60  of the apparatus.  
         [0056]     Cog  54  is arranged to fit inside a circular track which is formed on the inner surface of a ring  62 . Together, the circular track and the ring  62  are an internal gear. Cog  54  has teeth, as is conventional. The track has similarly dimensioned teeth. The sets of teeth are intermeshable so that movement of the cog  54  with respect to the track leads to rotation of cog  54  with respect to the track. The cog arrangement is described in more detail below.  
         [0057]      FIG. 3  shows, schematically, the cog arrangement of a preferred embodiment of the invention. For clarity, the teeth of the cog  54  are not shown. Cog  54  is arranged so that it can travel around the track  70 . Again, for clarity, the outer dimensions of the ring  62  are not shown and the teeth of the track  70  are not shown.  
         [0058]     Due to the intermeshing of the respective teeth of cog  54  and track  70 ,  54  rotates about pinion shaft  56 . Therefore cog  54  rotates with respect to track  70 . As explained in more detail further below, cog  54  is constrained to move in a circular path around the track  70  so that, in use, at least one tooth of cog  54  is in contact with a tooth of track  70 .  
         [0059]     In this preferred embodiment, cog  54  has a diameter B which is half the inner diameter C of the track  70 . It will be clear that a given point on the surface of cog  54 , e.g. point D, has a locus which is a straight line (shown in  FIG. 3  as a dashed line) passing through the centre of the circular track  70 . In other words, when cog  54  rotates around track  70 , point D describes a path within the ring  62  which is a straight line passing (at least approximately) through the centre point of ring  62 .  
         [0060]     Cog  54  is forced to roll around the track  70  by movement of pinion shaft  56 . Shaft  56  is eccentrically mounted with respect to drive shaft  72 . Rotation of shaft  72  forces shaft  56  to describe a circular path. In this way, cog  54  is forced to rotate with respect to track  70 .  
         [0061]     The centre of cam  52  is typically located level with the circumference of cog  54 , e.g. level with point D. Therefore, the cam describes a similar path to point D. As described above, this motion is transferred to rod  28 . According to the above description, rotation of drive shaft  72  would lead to one-dimensional motion of rod  28 , along a direction parallel to the movement of point D.  
         [0062]     Turning back to  FIG. 3 , the path of point D in space can be altered by moving the track  70 . The path of point D is fixed with respect to the track  70 . However, if the track itself is rotated, then the path of point D moves with the track. Clearly, with any suitable combination of movement of track  70  and cog  54 , point D can be placed at any spatial point within the circle defined by track  70 . Similarly, with any suitable combination of movement of the track and cog, point D can be made to trace out any desired path or shape within the circle defined by track  70 .  
         [0063]     Looking now at  FIG. 6 , the movement of the cog  54  around the track  70  (internal gear) is shown in four stages. The cog  54  is mounted on movement transmission block  55 . The cam  52  is mounted on the transmission block  55 . The centre of cam  52  is level with a point on the perimeter of cog  54 , but the cam  52  is axially displaced from the cog  54  so as not to interfere with the movement of cog  54  around the track  70 .  
         [0064]     Movement of the cog  54  around track  70 , shown in  FIG. 6  in four stages, makes cam  52  move in a straight line parallel to a diameter line of the track  70 . Clearly, rotation of the ring  62  can give rise to deflection of the path of the cam  52 .  
         [0065]     The arrangement of the cog and internal gear and associated drive shafts and bearings is shown more clearly in the exploded schematic view in  FIG. 7 .  
         [0066]     In this preferred embodiment, track  70  is attached to hollow drive shaft  74  via mounting block attachment means  76 . Drive shaft  74  is rotatably mounted with respect to the housing  60  via bearings  78 . Bearings  78  are retained by bearing sleeve  79 . Similarly, drive shaft  72  is rotatably mounted with respect to drive shaft  74  via bearings  80 .  
         [0067]     By suitable rotation of drive shaft  74 , the ring  62  (and hence track  70 ) may be rotated about the principle axis which is common to the drive shaft  74  and the ring  62  and the drive shaft  72 . The ring  62  and the cog  54  rotate in the same plane of rotation, perpendicular to this principle axis.  
         [0068]     Since rotation of both the cog  54  and the track  70  allow for the movement of point D to be controlled, suitable control of drive shafts  72  and  74  allows control of the position of cam  52  in two dimensions. This movement is transferred to rod  28  which is able to move in two dimensions due to bearings  32 ,  34 ,  38 ,  40 . Therefore, control of the movement of manifold  20  in two dimensions is possible.  
         [0069]     The size of the shape which point D can describe is limited by the diameter C. The apparatus is typically arranged so that ring  62  and cog  54  can be changed for a different combination of ring and cog, with different dimensions.  
         [0070]     Referring back to  FIG. 1 , the apparatus in this embodiment has a second rod  30  so that the position of the manifold  20  may be controlled with greater precision. The position of rod  30  is controlled by similar means to that which controls the position of rod  28 .  
         [0071]     Shaft  74  is driven via a belt  90  from pulley  82  to pulley  84 . The rotation of pulley  82  is controlled by a servo motor. This arrangement makes up the vertical drive.  
         [0072]     Shaft  72  is driven by a belt  80  from pulley  86  to pulley  88 . The rotation of pulley  86  is controlled by a servo motor. This arrangement makes up the horizontal drive. Rotation of shaft  72  is transferred to corresponding shaft  92  via a releasable coupling of  94 .  
         [0073]      FIG. 4  shows the horizontal drive in a view along the principle axis of shaft  72 . Pulley  86  is driven by a servo motor.  
         [0074]      FIG. 5  shows the vertical drive in view along the principle axis of shaft  74 . Pulley  100  is driven by a servo motor. Pulley  100  thereby drives a belt  102  which drives pulley  82 . In turn, pulley  82  drives pulley  84  via belt  90 .  
         [0075]     Typically, in use, the vertical drive may be used continuously, to give the manifold a consistent, vertical stroke. Then, a precise horizontal motion may be superimposed onto the vertical stroke to give precise control of the manifold power during the vertical stroke.  
         [0076]     Precise control of the position of manifold  20  requires very careful control of the output of the servo motors.  
         [0077]     The voltage input to a servo motor and the load on it determine the servo output speed. Therefore, it is possible very precisely to control the output of each servo. Co-ordinated control of the voltage input to the servo to give a determined output to form a particular shape is a complex operation. Typically, the voltage input to the servo motors is controlled by a suitably programmed computer.  
         [0078]     The computer should have an interface by which to control the servos. In addition, the computer should have a user interface whereby a user can control the computer, e.g. by inputting a desired path for the manifold to trace out, at a particular cyclic rate and speed.  
         [0079]     The computer typically runs using modified robotic software. Such software allows the precise co-ordinated control of electric motors, for example, in response to pre-programmed or user-defined parameters. The software utilises inverse and forward kinematics. The software is not described further here.  
         [0080]     In a further preferred embodiment, the apparatus typically has a controllable counterbalance weight assembly. This is used to suppress vibrations in the main apparatus induced by rapid movement of the moving parts in the assembly. Due to its eccentric path, cog  54  and associated piston shaft  56  may cause vibrations in the apparatus during use weights which are arranged in a suitable formation can move in the apparatus substantially to cancel out these vibrations. Typically the weights are arranged to move in a mirror image of the movement of the parts causing the vibration. Minimisation of vibrations helps to optimise the speed at which the apparatus can perform its movements and also optimise the smoothness of the movement. Using the apparatus, cyclic movement speeds of around 100 cycles per minute are possible. Optimisation of the speed can allow cyclic movement speeds of up to 400 cycles per minute or more.  
         [0081]     The stretcher of a controllable counterbalance weight assembly  140  is shown schematically in  FIG. 8 . The assembly is mechanically attached to the main apparatus. The assembly  140  has a shaft  142  which is rotatably mounted, via bearings  144 ,  146 , with respect to the main apparatus. The shaft  142  has weights  148 ,  150  mounted thereon. The weights  148 ,  150  are mounted eccentrically with respect to the shaft  142 .  
         [0082]     Shaft  142  is rotatable via pulley  152  and belt  154 , these bring driven by servo motor  156 .  
         [0083]     The apparatus has an accelerometer (not shown) attached to its frame. This detects vibration of the frame. Typically, the frame has a vertical accelerometer and a horizontal accelerometer, for detecting horizontal and vertical components of vibration, respectively. The control computer analyses data from the accelerometer. In response to this, to reduce vibration, the computer may operate the counterbalance assembly  140 . The computer controls the input voltage to the servo motor  156  in order to control the frequency of the vibrations output by the counterbalancing assembly  140 . Clearly, control of the speed of the servo motor controls the frequency of the vibration output.  
         [0084]     The size and mass of the weights  148 ,  150  used and the degree of the eccentricity of their mounting with respect to shaft  142  determines the types of vibrations which can be counterbalanced by the assembly  140 . Alteration of these parameters can be used to adjust the assembly to counterbalance different vibrations.  
         [0085]     The smoothness of the movement can also be controlled by suitable control of the servo motors which drive the movement. In particular, the ramping of the control voltage to the motors by the computer can be controlled to optimise smoothness.  
         [0086]     The present invention clearly has applications in many different areas of technology. In particular, it is suitable where controlled cyclic positional movement is required. Furthermore, it is suitable for repetitive processing, for example where a similar process must be carried out on a succession of items. Typically, items in a production facility are transported from one process to the next via a conveyor belt. In large output facilities, the items may be transported on the conveyor in ranked rows. It is often necessary to “index” the items, for example if the regimentation of the items on the conveyor is distorted. The movement output apparatus described may be used to re-position the items on a conveyor belt. This could be done by an appropriate pushing movement of a pusher plate with protruding fingers. Thus, a row of ranked items could be re-positioned forwards and laterally on the conveyor belt.  
         [0087]     Of course, the apparatus could be mounted in various different positions with respect to a conveyor belt, e.g. over, under and/or at right angles or offset angles/positions to the conveyor.  
         [0088]     The embodiments described in detail relate to food processing but the invention has applications in other fields of technology, for example machinging, where precise control of the shape described by a moving part (for example a machine tool) may be required. An example of this would be the mass machining of wooden items. Other manufacturing areas where the invention has applications are the toy manufacturing industry and other high volume, small item manufacturing or processing industries.  
         [0089]     The invention has been described by way of example only. Modifications of the embodiments described, and further embodiments and modifications thereof will be obvious to the person skilled in the art and as such are within the scope of the invention.