US20190217976A1

US20190217976A1 - Lidding machine and method

Info

Publication number: US20190217976A1
Application number: US16/247,919
Authority: US
Inventors: Alistair Paton
Original assignee: Proseal UK Ltd
Current assignee: Proseal UK Ltd
Priority date: 2018-01-15
Filing date: 2019-01-15
Publication date: 2019-07-18
Also published as: GB2570155A; DE202019100152U1; GB201800609D0

Abstract

A lidding machine with a conveyor 7 for conveying containers and a set of jaws 11 positioned at opposite sides respectively of the containers. The jaws move towards and each other over the conveyor and upwards away from the conveyor to lift one or more containers 22 off the conveyor and urge each container into contact with a lid 23 supported over the conveyor by a picking head 19 arranged to move on a rotating support 21 to transport lids between a lid magazine 16 and a position where lids and containers can be fitted together.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a lidding machine for affixing lids to containers and particularly, but not exclusively, mechanically fitted lids such as click and press fit lids. It also relates to a method of using the lidding machine.

BACKGROUND TO THE INVENTION

In a first existing lidding machine, containers advance along a conveyor to a lidding station where stops and guides associated with the conveyor position the containers. A picking head picks lids from a magazine positioned directly above the conveyor, rotates through 180 degrees and places the lids onto containers on the conveyor.
A problem with this machine is that the force required to urge the lids onto the containers must be supported by the inherent strength of the container. If the force is too great containers can be easily damaged. If the force is too weak the lids may not be properly fitted, if at all.
Another problem is that arranging for the picking head to provide sufficient force to urge multiple lids onto containers increases its mass making it more difficult for it to rotate quickly.
In a second existing lidding machine, containers advance along a relatively narrow conveyor, which they overhang on opposite lateral edges. A lower tool rises from beneath and at each side of the conveyor. The tool supports containers under part of a rim of the container that overhangs the conveyor, lifts the container off the conveyor, urges it onto contact with an upper tool on which a container lid is retained by vacuum and thus urging the lid onto the container. A sliding carriage is arranged to travel between a container magazine and the upper tool to transfer another lid to the upper tool ready for another container.
This machine goes some way to addressing the problem with the first machine by supporting containers by their rim. However, it is only able to support containers under the part of their rim which overhangs the conveyor which may only be a small proportion of the rim. It is also relatively inflexible in accommodating different sizes of container since it is necessary for the container to overhang the conveyor by a reasonable amount to enable it to be lifted by the lower tool and yet if too great a proportion of a container overhangs the conveyor it may become unstable. Also, accommodating containers of different lengths effectively requires a redesign and replacement of both the upper and lower tools, which is impractical.
It is an object of embodiments of the present invention to address the problems associated with these existing machines.

SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a lidding machine comprising:
a conveyor for conveying containers;
a set of jaws positioned at opposite sides respectively of the conveyor the jaws being arranged to move towards each other over the conveyor and upwards away from the conveyor thereby to lift one or more containers off the conveyor and urge the/or each container into contact with a respective lid positioned over the conveyor;
a lid magazine for storing lids;
a picking head for supporting one or more lids over the conveyor, the picking head being mounted to a picking head support, the picking head support being mounted for rotation about an axis substantially parallel to a direction of travel of the conveyor enabling the picking head to be moved between a first position where the picking head can pick one or more lids from the lid magazine and a second position where the picking head can support one or more lids above the conveyor enabling containers and lids to be urged together,
wherein the picking head support rotates through less than 150 degrees in order to move the picking head between its first and second positions.
Provision of moveable jaws enables the machine to accommodate a variety of sizes of container on the same sized conveyor as there is no need for the containers to overhang the conveyor. It also enables containers to be supported around a significant proportion of their periphery thus facilitating fitment of a lid. The jaws may also provide the necessary force to urge lids and containers together so that this does not need to be provided by, for example, a picking head.
Positioning the lid magazine so that the picking head support rotates through less than 150 degrees from its first to its second position and vice versa reduces the time taken for that movement as compared to moving through 180 degrees, as with prior arrangements. This enables the machine to operate more quickly. Also, positioning the lidding magazine in this way results in stacks of lids supported in the magazine extending at an angle of at least 60 degrees to the horizontal. This facilitates loading of lids as compared to a vertical stack of lids as its overall height is reduced for an equivalent number of lids, making it easier for an operator to access.
In an embodiment the picking head support rotates through less than 140 degrees or about 135 degrees to move the picking head between the two positions. In the latter embodiment stacks of lids are supported in the magazine at an angle of about 45 degrees to the horizontal.
The conveyor may extend, and transport containers, in a longitudinal direction of the machine. The conveyor may comprise one or more conveyor belts or other endless conveyors, or may comprise rollers or take any other suitable form.
The jaws may move towards each other in a direction transverse to the direction of the conveyor. The jaws preferably move towards each other to a position where they are close together, but spaced apart. Alternatively they could contact each other.
The jaws may move in an upwards or downwards direction whilst, for at least some of this movement, also moving towards or away from each other. This may assist in reducing a cycle time of the machine.
The jaws may be fixed longitudinally relative to the conveyor. Alternatively the jaws may be arranged to move longitudinally. This may also help to reduce a cycle time of the machine by enabling the jaws to begin moving together whilst containers are moving on the conveyor.
Opposed edges of each jaw may comprise one or more recesses arranged to fit partially around a container to be handled by the machine such as part circular and/or part rectangular recesses. The jaws may be arranged to fit under a rim or other laterally extending feature of a container thereby enabling the jaws to lift the container by supporting it via the laterally extending feature. Opposed edges of each jaw may comprise one or more raised walls or other formations arranged to be received into a rim or other feature of a container. Preferably the jaws are arranged to support a container by or adjacent a feature of the container with which a lid for the container is intended to cooperate.
Alternatively or additionally the jaws may be arranged to grip a container.
The jaws may be substantial mirror opposites of each other.
The jaws may be arranged to move using any suitable structure. They may be slidably mounted to each other or to a support, such as a support plate, enabling them to move towards and away from each other. They may move towards and away from each other in a planar fashion, or they could be pivoted together and move through arcs. Preferably both jaws are arranged to move laterally relative to the conveyor.
The jaws or any support to which are they are mounted may be mounted to a structure operative to raise and lower the jaws relative to the conveyor. The structure may be a platform.
One or more actuators may be provided to move the jaws towards and away from each other, and one or more actuators may be provided to move the jaws upwards and downwards relative to the conveyor. Any suitable type or combination of types of actuators may be used, for example electrical, hydraulic or pneumatic. The actuators could be linear or rotary and a suitable mechanism, such as a crank or cam, employed to convert rotary to linear motion.
The lidding machine may comprise a picking head for supporting one or more lids over the conveyor. The picking head may comprise one or more formations for locating one or more lids. The formations may be provided on a plate and may be sized and shaped to cooperate with the shape of the top of a lid. For example, where the lid has a circular recess in its top surface the formation may be substantially cylindrical or frustro-conical in shape. The picking head may retain lids by vacuum. It may comprise one or more apertures that may be selectively connected to a source of vacuum thereby to retain and release a lid or lids.
The lidding machine may comprising a lid magazine for storing lids and from which the picking head may pick lids to be fitted to containers. The magazine may comprise a structure such as a plate comprising apertures through which individual lids may be drawn. Supports may be provided for supporting a stack of lids over each aperture. Elongate rods, walls or other structures surrounding the apertures may provide suitable supports.
The picking head may be mounted to a moveable picking head support which enables the picking head to be moved between a first position where the picking head can pick one or more lids from the lid magazine and a second position where the picking head can support one or more lids above the conveyor enabling containers and lids to be urged together. The picking head support may be mounted for rotation about an axis substantially parallel to the longitudinal axis of the conveyor. With this arrangement the picking head support is preferably arranged to rotate through less than 180 or 150 degrees in order to move the picking head between its first and second positions. In an embodiment the picking head support rotates through about 135 degrees to move the picking head between the two positions.
The picking head may be moveably mounted to the picking head support so that the picking head may move perpendicular to the axis of rotation of the picking head support. This may enable the picking head to be moved towards the lid magazine to pick one or more lids. The picking head could also thus be moved towards a container or containers to urge or assist in urging a lid onto the/or each container although typically this is not a preferred mode of operation. The picking head may be movably mounted to the picking head support. One or more actuators, particularly linear actuators, may be provided to move the picking head relative to the support.
According to another aspect of the present invention there is provided a method of fixing a lid to a container comprising the steps of providing a lidding machine according to the first aspect of the invention, placing the container on the conveyor and causing the conveyor to move the container to a predetermined position between the jaws, causing the jaws to move towards each other, and causing the jaws to lift the container off the conveyor and urge it into contact with a lid supported above the conveyor.
The lid and the container may fit together mechanically, such as with a click or press fit.
The machine may be provided with a controller, such as a programmable controller, operative to cause the machine to perform the method automatically.
The method may further comprise any or all of the steps of: lowering the jaws to lower containers back onto the conveyor; moving the jaws away from each other and causing the conveyor to move the container out of the machine.
The method may further comprise the step of: picking a lid from a magazine with the picking head and moving the lid to a position above the conveyor.
The method may involve simultaneously fitting lids to multiple containers, for example two, three, four, five, six or more containers, and may be automatically repeated.

DETAILED DESCRIPTION OF THE INVENTION

In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

FIG. 1 is a perspective view from the front and above of a lidding machine;

FIG. 2 is a perspective view of the jaws of the machine, holding a single container;

FIG. 3 is a perspective view of the support structure for the jaws of the machine;

FIG. 4 is a perspective view of part of the picking head of the machine;

FIG. 5 is a front part cut away view of the machine with guards removed in a first state;

FIG. 6 is a right side part cut away view of the machine in a second state;

FIG. 7 is a right side part cut away view of the machine in a third state;

FIG. 8 is a part cut away perspective view from the front and above of the machine in the third state;

FIG. 9 is a right side part cut away view of the machine in a fourth state;

FIG. 10 is a front part cut away view of the machine with guards removed in a fifth state;

FIG. 11 is a right side part cut away view of the machine in the fifth state;

FIG. 12 is a right side part cut away view of the machine in a sixth state;

FIG. 13 is a right side part cut away view of the machine in a seventh state;

FIG. 14 is a front part cut away view of the machine with guards removed in an eighth state;

FIG. 15 is a right side part cut away view of the machine in the eighth state;

FIG. 16 is a right side part cut away view of the machine in a ninth state;

FIG. 17 is a front part cut away view of the machine with guards removed in a tenth state;

FIG. 18 is a right side part cut away view of the machine in the tenth state;

FIG. 19 is a right side part cut away view of the machine in an eleventh state;

FIG. 20 is a front part cut away view of the machine with guards removed in the eleventh state; and

FIG. 21 is a front part cut away view of the machine with guards removed in a twelfth state.

In what follows the terms the terms top, bottom, front, rear, left, right and like terms are used to refer to the lidding machine and its components in the orientation shown in the drawings, which is the orientation in which it is intended to be used, but should not be taken as otherwise limiting. Like reference numerals are used to denote like features throughout the drawings, which are not to scale.
Referring to the drawings, the lidding machine comprises a main body in the form of a cabinet 1 provided with castors 2 to facilitate movement and adjustable feet 3 for supporting the machine when in use. The cabinet houses a lidding station, generally 4, over which is a second cabinet 5 housing switchgear and programmable control apparatus.
A first, infeed, servo motor driven conveyor belt 6 is supported on the outside left side of the cabinet 1 and extends towards an opening in the left side of the cabinet 1. A sensor 6 a is provided towards the end of the first conveyor 6 closest to the cabinet, operative to detect containers of the conveyor. A second, accumulation and outfeed, conveyor belt 7 extends from a position adjacent the end of the first conveyor 6 just outside the opening in the left hand side of the cabinet 1, through the lidding station 4 and out of an opening in the right hand side of the cabinet 1. The second conveyor extends only slightly out of the opening in the left hand side of the cabinet 1, but much further out of the opening in the right hand side of the cabinet so that about half of its length extends out of the right hand side of the cabinet 1. The second conveyer belt 7 is narrower than the first conveyor belt 6.
Removable guards 8, 9, supported on the cabinet 1, are fitted over the first 6 and second 7 conveyors where they extend outside the cabinet. A removable guard 10 is fitted over an opening in the front of the cabinet.
The lidding station 4 comprises a set of two of opposed jaws positioned above and at opposite sides respectively of the second conveyor belt 7. The jaws (best seen in FIG. 2) are formed from two elongate, generally rectangular, plates 11 each lying in substantially the same plane, substantially parallel to, but (when in a lowest position) slightly spaced above, the surface of the second conveyor belt 7. The opposed edges 12 of the plates 11 are shaped to conform to the edges of multiple spaced apart containers to be handled.
In the illustrated example the edges 12 define six substantially rectangular recesses with curved corners. The opposed sides of each recess extend substantially parallel to each other from the back of the recess over a little over half of their length and diverge slightly from each other over the remainder of their length. This the width of the recess narrows slightly from its opening. These recesses are suitable for accommodating containers with a substantially rectangular cross-section. The top surface of the plates 11 is substantially flat. A respective upstanding wall 12 a is formed on the top of the plate adjacent part of the edge of each recess, extending adjacent the back of the recess and the part of the sidewalls which are substantially parallel, effectively forming an upward extension of the side 12 of the plate 11.
Of course the shape of the recesses may be varied according to the shape of the containers it is desired to handle. In another example the edges 12 of the plates are provided with recesses formed by curves of constant radius each extending through about 160 degrees. These are suitable for handling containers with a substantially circular cross-section of a similar radius.
The plates 11 are each mounted on a support structure best shown generally in FIG. 3. The support structure comprises a respective stand for each plate. Each stand comprises an upper substantially rectangular plate 13 which is slightly longer but narrower than the plate 11 it supports. The plates 11 forming the jaws are mounted on the upper plates 13 so that their opposed edges 12 overhang the edges of the upper plates 13. The stand plates 13 are supported by upright plates 14, one at each end and two spaced in between. The upright plates 14 are generally trapezoidal (or some other suitable shape) with upper and lower parallel edges and may define an aperture so as to reduce the mass of material required to form the plates. The upper edge has a cut out into which the stand plate 13 is received so that the opposed edges of the stand plates 13 at least lie flush with, or overhang, the inner edges of the upright plates 14. The upright plates are wider at the bottom than the top.
The upright plates 14 of each stand are supported on sliding elongate generally rectangular plates 15 which extend substantially parallel to the upper stand plates 13. The sliding plates 15 are each movably mounted to rails 15 a mounted on a platform 16 beneath the plates allowing the sliding plates 15 in a direction substantially transverse to the direction of the second conveyor 7. This enables the jaws to move towards and away from each other. Movement of the sliding plates 15 is effected by two servo motors or other suitable rotary actuators 16 a mounted to the underside of the platform 16 one under the position of each sliding plate. Each motor 16 a drives a shaft which extends through the platform 16. A bearing 16 b is mounted to each shaft off its axis of rotation and a bearing 16 b is slidably received into a parallel sided slot 15 b formed in each plate 15 extending substantially perpendicularly to the direction of movement of the plate 15. Thus, rotation of the servomotors causes transverse movement of the plates. Of course other suitable actuators, such as linear actuators, could be provided to move the sliding plates 15 between outer and inner positions.
The platform 16 is mounted to move upwards and downwards relative to the second conveyor 7. Movement is effected by a servo motor 16 c driving a crank disposed in a housing 16 d beneath the platform 16. A connecting rod is mounted to the crank and the platform.
Thus, it will be appreciated that each plate 11 forming a jaw can be moved both transversely and vertically relative to the direction of the conveyors 6, 7.
The lidding station 4 further comprises a lid magazine for storing lids for containers and a picking head for picking lids from the magazine and presenting them to containers to which they are to be fitted.
The lid magazine is formed by a substantially rectangular plate 17 which forms a wall of the cabinet 1. Its long sides extend parallel to the direction of the conveyors 6, 7 and its short sides extend at an angle of about 45 degrees to the horizontal so that it extends partially over the lidding station 4. Six, spaced apart, substantially rectangular apertures with curved corners 17 a extend through the plate 17. Four elongate rods 18 are positioned evenly around each aperture 17 a and extend substantially perpendicularly from the outside surface of the plate 17. The rods 18 are intended to support stacks of lids over each aperture 17 a. Another suitable structure could of course be employed to support lids over the apertures.
The picking head comprises an elongate substantially rectangular plate 19 (best shown in FIG. 4 on which are positioned six spaced apart upstanding substantially rectangular walls 19 a with curved corners. The thickness of each wall reduces in a step, in both the inside and outside of the wall, close to its free edge, so that there is a relatively narrow free edge 19 b to wall, surrounded on each side by a shoulder. Each wall surrounds a generally central, circular aperture through the plate to which is fitted a concertina tube 19 c formed of a resilient rubber or similar material which extends just beyond the free edge of the wall and terminates in a plane generally parallel to the plane of the opening defined by the free edges of the wall. Air may be drawn thought the tubes 19 c by a vacuum pump (not shown). The walls 19 a are positioned to correspond to the apertures 17 a in the lid magazine plate and to the recesses and surrounding walls 12 a of the jaws.
The plate 19 is slidably mounted to a rotating support 21. The rotating support is operative to rotate about an axis extending above and parallel to a centre lie of the second conveyor 7 to move the plate 19 between a picking position in which it is substantially parallel to the plate 17 of the lid magazine and a placing position in which it is substantially parallel to the surface of the second conveyor 7. This involves rotation through about 135 degrees.
Movement of the rotating support 21 is effected by a rotary actuator 21 a. Movement of the plate 19 radially relative to the support 21 is effected by a linear actuator 20, which may be implemented by a rotary actuator driving an eccentric or crank. Springs (not shown) are provided to form resilient stops which arrest movement of the plate as it is moved to its radially innermost position relative to the support 21. Any suitable type of spring or indeed another suitable resilient member or members may be used to provide the stop(s).
The control apparatus is programmed to cause the conveyor servo motors and actuators of the lidding station to operate automatically to place click or other mechanically fitted lids to containers by repeatedly performing the follow sequence of operations.
As shown in FIG. 5, open containers 22 are placed onto the first conveyor 7. In this example the containers have a generally rectangular base, four rectangular sides and four elongate triangular sides (one between each adjacent rectangular side) a point of each of which is positioned at a corner of the base. So the container is generally cuboidal with an increasing cross-sectional area from base to top, where a rim is formed for receiving a click-fit lid. Lids 23 are placed into the lid magazine. The lids are substantially rectangular with curved corners and an edge formation intended to fit over the rim of a container 22. In the opposite face of the lid (that which is exposed when the lid is fitted to a container) a generally rectangular channel is formed, with curved corners, sized to fit over the narrow part 19 b of the walls on the plate 19 of the picking head.
The first and second conveyors 6, 7 are operated by the control apparatus in dependence on information received from the sensor 6 a associated with the first conveyor so that six containers 22 are advanced from the first conveyor 6 to the second conveyor so they are spaced apart on the second conveyor 7 in a predetermined way, each container being positioned between respective opposed recesses 12 in the jaws of the lidding station 4, as shown in FIG. 6. Operation of conveyors in this manner to position containers with a desired spacing is known and within the capability of a person of ordinary skill in the art and so is not described in further detail here. At this stage the platform 16 is in its lower position and the sliding plates 15 are at their outermost positions. As such, the opposed edges 12 of the jaws are each spaced laterally away from the edges of the second conveyor 7 and the lower surfaces of the jaws are closely spaced above the plane of the surface of the second conveyor. The plate 19 of the picking head lies substantially parallel to the plate 16 of the lid magazine, but at its radially innermost position.
Vacuum is now applied to the apertures through the tubes 19 c on the plate 19 of the picking head and the actuator 20 operated to move the picking head radially outwards towards the plate 16 of the lid magazine as shown in FIG. 5. This causes the lowermost lids in the stacks on the magazine to be drawn onto the plate so that the narrow edge 19 b of walls on the plate 19 is received into the corresponding channel in the lids, thus locating the lids in desired positions on the plate 19, as illustrated in FIG. 3 where a single lid 23 is shown in broken lines.
The linear actuator 20 is now operated to move the picking head radially inwards to the position shown in FIG. 9, carrying six individual lids 23 with it.
Next, the picking head is rotated through about 135 degrees by the rotary actuator 21 so that the plate 19 is substantially parallel with the surface of the second conveyor 7, as shown in FIGS. 10 and 11. The lids 23 retained on the picking head are each now positioned over a respective container 22 on the second conveyor 7.
The sliding plates 15 are now moved towards each other to their inner most positions, to the position shown in FIG. 12. In this position the opposed faces 12 of the jaws 11 are still spaced apart so that the edges of the jaws partially encircle the containers. The jaws are positioned close to the surface of the second conveyor 7 and therefore towards the bottom of the containers 22 where their dimensions are smallest and smaller than those of the recesses in the jaws. This allows for some tolerance in the positioning of the containers 22 on the second conveyor 7, whilst avoiding the jaws contacting the containers as they move together and thus potentially upsetting the containers or their contents. Although, were the jaws to contact the containers, the shape of the recesses in the jaws would assist in positioning the containers as the jaws close.
Next, the platform 16 actuator is operated to raise the platform 16. As the platform is raised the jaws 11 move upwards relative to the containers 22 until the containers are supported on the jaws with the upstanding walls 12 a on the jaws received in the rim of the containers as shown in FIG. 13 and also FIG. 2 where a single container 22 is shown in broken lines. It will be noted that, owing to the gradually increasing dimensions of the containers from base to top, as the jaws are raised the containers will become positioned correctly between them if they are not already in this position on the second conveyor 7.
As the platform 16 continues to rise the jaws lift the containers 22 off the second conveyor and urge them into contact with the lids 23 on the picking head, as shown in FIGS. 14 and 15, fitting the lids onto the containers.
At this stage, the plate 19 of the picking head 4 is at its radially innermost position and it is the action of the vertical platform 16 actuator which urges the containers and lids together, also urging the plate 19 of the picking head against its resilient stops. The stops serve to limit the maximum force applied between the jaws and picking head, simplifying control of the actuators whilst avoiding damage of the containers and lids. Alternatively or additionally the platform 16 may be sprung.
The vacuum is now disconnected from the picking head, releasing the lids from the head, and the platform actuator lowered through the position shown in FIG. 16 to the position shown in FIGS. 17 and 18, placing the containers back onto the second conveyor 7.
The sliding plates 15 are now moved away from each other to their outermost positions to the position shown in FIGS. 19 and 20. The jaws are now clear of the containers and the second conveyor 7 is run to move the containers 22 with fitted lids 23 out of the lidding station through the opening on the right hand side of the machine.
The process can now be repeated.
It will be appreciated that some of the steps of the process described above may be performed simultaneously to achieve an overall reduction in cycle time. For example the picking head may pick lids and position these over the second conveyor as containers are advanced onto the conveyor. Open containers may also be introduced onto the second conveyor as the lidded containers are moved out of the lidding station.
Cycle time can also be saved by only lowering the platform sufficient for the raised walls 12 a of the jaws 11 to pass under the rim of a container 22, rather than to their lowermost position, thus minimising the required stroke of the platform actuator.
For containers of different shapes the jaws can conveniently be set to approach the containers at a height above the point of greatest dimension of the container, when this lies below the container rim.
The above embodiment is are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A lidding machine comprising:

a conveyor for conveying containers;

a set of jaws positioned at opposite sides respectively of the conveyor the jaws being arranged to move towards each other over the conveyor and upwards away from the conveyor thereby to lift one or more containers off the conveyor and urge the/or each container into contact with a respective lid positioned over the conveyor;

a lid magazine for storing lids;

a picking head for supporting one or more lids over the conveyor, the picking head being mounted to a picking head support, the picking head support being mounted for rotation about an axis substantially parallel to a direction of travel of the conveyor enabling the picking head to be moved between a first position where the picking head can pick one or more lids from the lid magazine and a second position where the picking head can support one or more lids above the conveyor enabling containers and lids to be urged together,

wherein the picking head support rotates through less than 150 degrees in order to move the picking head between its first and second positions.

2. A lidding machine as claimed in claim 1 wherein opposed edges of each jaw comprise one or more recesses arranged to fit around part of a container to be handled by the machine.

3. A lidding machine as claimed in claim 1 wherein opposed edges of each jaw comprise part circular and/or part rectangular recesses.

4. A lidding machine as claimed in claim 1 wherein opposed edges of each jaw comprise one or more raised walls arranged to be received into a rim of a container to be handled by the machine.

5. A lidding machine as claimed in claim 1 wherein the jaws are substantial mirror opposites of each other.

6. A lidding machine as claimed in claim 1 wherein the jaws are each slidably mounted to each other or to a support enabling them to move towards and away from each other.

7. A lidding machine as claimed in claim 6 wherein the jaws or the support are/is mounted to a structure operative to raise and lower the jaws relative to the conveyor.

8. A lidding machine as claimed in claim 1 wherein the picking head comprises one or more formations for locating one or more lids.

9. A lidding machine as claimed in 1 wherein the picking head support rotates through less than 140 degrees in order to move the picking head between its first and second positions.

10. A lidding machine as claimed in claim 1 wherein the picking head is moveably mounted to the picking head support so that the picking head may move perpendicular to the axis of rotation of the picking head support.

11. A method of fixing a lid to a container comprising the steps of providing a lidding machine as claimed in any preceding claim, placing the container on the conveyor and causing the conveyor to move the container to a predetermined position between the jaws, causing the jaws to move towards each other, and causing the jaws to lift the container off the conveyor and urge it into contact with a lid supported above the conveyor.

12. A method as claimed in claim 11 where the lid and the container fit together mechanically.

13. A method as claimed in claim 11 further comprising: lowering the jaws to lower containers back onto the conveyor, moving the jaws away from each other and causing the conveyor to move the containers out of the machine.

14. A method as claimed in claim 11 further comprising the step of: picking a lid from a magazine with the picking head and moving the lid to a position above the conveyor.