FIELD OF THE INVENTION The present invention relates to an adjustable actuator assembly for use as part of a forming machine. More particularly, although not exclusively, the present invention relates to an adjustable actuator assembly for a rollforming machine. The present invention also relates to a forming machine fitted with at least one adjustable hydraulic actuator for use in forming operations.

BACKGROUND

In a rollforming process, sheets of material such as steel sheet are fed into a rollforming machine and undergo various forming operations at sequential stations such as bending, hole punching, dimpling and similar, to form the required final shape. The final forming station in the sequence is used to perform the final shaping operations on the item, and to cut the shaped item to the required length. A final station (in this case, a shearing station) such as is known in the art is shown in figure 1 . The formed material enters the shearing station and passes across the top of a shear platform, which is aligned so that the top surface generally forms a horizontal plane. A shearing assembly that includes a generally vertically aligned shear blade is also mounted on the shear platform. In use, the shear blade moves upwards and downwards vertically in order to cut the formed item to the required length as it is fed across the top of the shear platform. The shearing assembly also includes a pair of side crimp sub-assemblies located so that in use the material passes between them. The side crimp subassemblies each have a cam roller associated with them, and are connected to the remainder of the shearing assembly via a cam plate, the cam rollers locating into the cam plates in use. As the shearing assembly moves upwards and downwards, the cam rollers move within the slots along a predetermined path, and this moves the side crimp subassemblies from side-to-side - that is, in a plane perpendicular to the direction of travel of the formed item.

The position of the side crimps can be adjusted in the arrangement described above. However, it is necessary to be very precise about positioning the dies correctly as it is easy to set the dies in the wrong position. This can lead to excessive load applied to the cam bearings, and a greater likelihood of the bearings failing prematurely. These bearings are difficult and expensive to replace.

It is an object of the present invention to provide an adjustable actuator assembly for use as part of a forming machine which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

It is a further object of the invention to provide a forming machine that has an adjustable actuator assembly which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

Advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiment of the invention without placing limitations thereon.

The background discussion (including any potential prior art) is not to be taken as an admission of the common general knowledge. Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

SUMMARY OF THE INVENTION In a first aspect, the invention may broadly be said to consist in an adjustable actuator assembly for a forming machine, comprising:

an actuator body, having means for attaching the actuator body to a surface, and an internal passage aligned to run substantially parallel to the surface on attachment;

a piston body, sized with and locating into the internal passage in use, the piston body and block mutually adapted so that the piston body will be held within the block and in use move inwards through a fixed stroke length within the block on application of an actuating force, and then outwards back to the starting or initial position once the actuating force is removed; a rod, axial ly nested in the piston body;

a locking element connecting between the piston body and the rod, so that the rod is connected to and moves with the piston through the piston stroke;

the rod and piston body adapted so that the axial position of the rod in relation to the piston body can be changed, with the piston body still moving through a fixed stroke length.

Preferably the locking element connects between the outer end of the piston body and the outer end of the rod, the outer end of the rod and the locking element mutually threaded. Preferably the outer end of the rod has an adjustment element, manipulation of the adjustment element causing the rod to rotate within the locking element and move axial ly.

Preferably the rod inner end extends from the piston inner end and is adapted for attachment to a tool.

Preferably the piston stroke is substantially between 10 and 1 2mm. Brief Description of the Drawings

Embodiments of the present invention wil l now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a shear station as is known in the art for use as part of a rol lforming machine, with a pair of side crimp sub-assemblies located one to each side of a shearing assembly, the side crimp subassemblies moved sideways across the line forming station by way of cam rollers moving within slots;

Figure 2 shows an exploded view of a shear station for use as part of a rol lforming machine, a pair of side crimp sub-assemblies located one to each side of a shear blade assembly, each side crimp sub-assembly connected to a hydraul ic actuator, the hydraulic actuators held in position by way of a actuator body connected to a mounting plate, the hydraulic actuators moving the side crimp subassembl ies across the mounting plate, the hydraulic actuators adjustable to alter the initial position of the side crimp subassemblies; Figure 3a shows a perspective view of the actuator body and associated hydraulic actuator of figure 2, with a crimp plate grip shown in position on the inner end of the actuator;

Figure 3b shows an exploded perspective view of the actuator body, associated hydraulic actuator, and crimp plate grip of figure 3a;

Figure 4a shows a cutaway side view of the actuator body and a piston assembly that forms part of the hydraulic actuator of figures 3a and 3b, the piston assembly shown in position in the actuator body, the piston assembly having an internal adjustment rod that is shown adjusted to a maximum outwards position; shows the arrangement of figure 4a, with the adjustment rod shown adjusted to maximum inwards position; shows an exploded view of the actuator body and piston assembly; shows the exploded view of figure 5 with the piston assembly further exploded to show further detai l;

Figures 7a and 7b show a cross-sectional side view of the piston assembly, the adjustment rod shown adjusted to a maximum inwards position and a maximum outwards position, respectively; and

Figure 8 shows an exploded perspective view of the piston assembly. DETAILED DESCRIPTION OF THE INVENTION

A shear station 1 is shown in figure 2. In the preferred embodiment, the shear station 1 is used as part of a roll-forming machine. Roll-formed material is fed across the top of a mounting plate 2 that forms part of the shear station 1 . The primary purpose of the shear station 1 is to cut formed material to the required length using a shear blade mounted in a shear blade assembly 3. The shear station 1 also has a pair of side crimp sub-assemblies 5, located one to each side of the shear blade assembly 3, so that their inner sides or edges can access the material as it moves across the mounting plate 2 from one side to the other. Each side crimp sub-assembly 5 is connected to a hydraulic actuator assembly 6, which acts to move the side crimp sub- assembly 5 inwards and outwards along a line perpendicular to the formed item moving across the mounting plate 2 from one end to the other. When activated, the side crimp sub-assemblies hold the material to provide a close cutting surface, so that a clean cut can be achieved. They then retract to allow the material to pass freely through the gap between the side crimp sub- assemblies 5. This operation also has the advantage of counteracting any shape change in the material due to earlier operations.

Each hydraulic actuator assembly 6 consists of an actuator body 7, and a piston assembly 8. The preferred embodiment of each actuator body 7 has four through holes or attachment holes 10 running vertically through the actuator body 7 and out of the flat base of the actuator body 7 so that in use cap screws or bolts 9 can be passed through the holes 10 into corresponding holes in the mounting plate 2 to attach the actuator body 7 to the mounting plate 2. The actuator body 7 has an internal horizontal passage 1 1, aligned so that when the actuator body 7 is connected to the plate 2, the passage 1 1 is parallel to the surface of the plate and perpendicular to the direction of travel of the formed material across the plate 2 from one end to the other. The passage 1 1 is sized to receive the piston assembly 8 in use. The preferred form of piston assembly 8 will now be described with particular reference to figures 4 to 8.

Each of the piston assemblies 8 has a piston 16. The piston 16 has an inner end 20. In use, the piston 16 of the piston assembly 8 is passed through the horizontal passage 1 1 , and is retained in the actuator body 7 by a side gland

13 at the outer end. The preferred embodiment of side gland 13 has a number of bolt holes 1 5 (preferably six, three at the top and three at the bottom) which pass through the side gland 13 and which correspond to holes in the rear or outer face of the actuator body 7, so that the side gland 13 can be bolted to the actuator body 7. It should be noted that although bolts are the preferred connection mechanism, the side gland can be attached in any suitable manner.

The actuator body 7 and piston 16 are sized so that the inner end 20 extends a short distance from the inner end of the passage 1 1 , and the outer end of the piston 16 extends outwards a short distance from the side gland 1 3. The inner end 20 forms a connector tip. In the preferred embodiment, a flange 21 is bolted to the inner end 20, and a spigot coupler 14 is removably mated to the flange 21 , by slipping it sideways over the flange 21 . In use, the inner end or side of the spigot coupler 14 connects to the outer side or edge of the side crimp subassembly 5, either directly, or indirectly using an intervening couple.

The actuator body 7 and piston 16 are mutually adapted so that the piston 16 moves through the length of its stroke within the actuator body 7 in use. An actuating force is applied to the piston and the piston moves inwards through the length of its stroke, and then outwards to the initial or starting position once the actuating force is removed. An adjustment bolt or adjustment rod 1 7 is co-located with the piston 16 so that when the piston 16 is activated, the rod 1 7 moves axially with the piston 16. In the preferred embodiment, the rod 17 is axially nested in the piston 16, passing axially along the length of the piston 16, so that the linear axes of the rod and piston coincide. When the piston 16 is in position in the actuator body 7, the inner end 20 of the rod 1 7 extends from the inner end of the piston 16, and the inner side of the actuator body 7. The outer ends of the piston 16 and rod 1 7 are co-located and extend outwards from the side gland 13. On actuation, the piston 16 moves through a fixed stroke length inwards through the actuator body 7, and then outwards back to the starting or initial position once the actuating force is removed. The associated rod 1 7 moves with the piston 16. The stroke of the piston 16 in the preferred embodiment is approximately 10-

12mm. Movement of the rod 1 7 in turn moves the spigot coupler 14 forwards so that a connected side crimp subassembly 5 moves inwards. In figure 4, the piston is shown activated - that is, at the inner end of its stroke. The initial position of the piston 16 relative to the actuator body 7 is fixed, as is the stroke length of the piston 16. However, the position of the rod 1 7 relative to the piston 16 (and therefore the actuator body 7) can be altered as described below. A lock nut 22 is located at the outer ends of the piston 16 and rod 1 7 to connect between the piston 16 and rod 1 7. An adjustment element 23 associated with the end of the rod 1 7 allows the rod 1 7 to be moved inwards and outwards, so that the relative positions of the piston 16 and rod 1 7 can be adjusted. In the preferred embodiment, the internal adjustment is carried out by way of an Allen key or similar, inserted into the outer end of the adjustment element 23. As described above, the side gland 13 is bolted to the actuator body 7. In turn, the actuator body 7 is rigidly connected to the mounting plate 2. Therefore, when the position of the rod 17 is altered in relation to the piston 16, the position of the inner end 20 in relation to the mounting plate 2 will also be altered. In this manner, the initial position of connected items such as the spigot coupler 14, and side crimp sub-assembly 5 can be adjusted.

What has been described above is a hydraulic actuator that has an adjustable initial position. Hydraulically actuated side dies are advantageous to cutting steel framing as they provide greater force on the cut product resulting in a neater cut. Also, a hydraulically actuated side die provides greater accuracy and speed of cutting. If different thicknesses of material are used, the ability to adjust the initial position provides an advantage as this assists in accounting for the different thicknesses and shapes of material. Also, adjustable and therefore accurate positioning of the cutting dies aids in achieving clean, accurate, good quality cutting. The hydraulically operated side die described above could also be used for crimping operations.