Metal deforming – By deflecting successively-presented portions of work during... – By use of deflector arranged to bend work transversely of...
Reexamination Certificate
2000-04-03
2001-09-04
Crane, Daniel C. (Department: 3725)
Metal deforming
By deflecting successively-presented portions of work during...
By use of deflector arranged to bend work transversely of...
C072S307000, C072S379600
Reexamination Certificate
active
06282936
ABSTRACT:
TECHNICAL FIELD
This invention relates to sheet metal buildings of relatively large size and more particularly but not exclusively to processes and apparatus for cold-forming elongate building elements of such buildings and methods of building construction.
BACKGROUND ART
The invention is particularly described with reference to longitudinally arcuate building elements. Typically building elements of this kind have been used to construct farm buildings, garages and the like of upwardly convexed arched structure comprising a plurality of prefabricated longitudinally arcuate elements that extend continuously from one side foundation of the building to the other arranged side by side with their abutting edges secured together thereby forming a stand alone building devoid of bracing, trusses or other structural reinforcements.
Traditionally the elements have been formed in two or more passes through roll forming apparatus or have required very long roll forming lines. Conventional processes and apparatus generally produce relatively short span elements which for long span buildings have been joined end to end with overlapping edge margins. Consequently, in constructing long span buildings, typically the short span elements are either joined end to end on the ground prior to being hoisted into position alongside previously erected elements and subsequently secured thereto edge to edge or are hoisted into their desired position individually for joining end to end and side to side with previously erected elements.
Both methods of construction are labour intensive and expensive.
Previously proposed buildings of this kind have not proven popular from either a commercial or manufacturing aspect. This appears due principally to high costs involved in formation and transportation of thin sheet metal elements of this kind and to handling difficulties and other constructional problems associated with such elements. Hence it is preferred that the formation of the building elements takes place at the site of the building to be erected. However, it has been found that conventional apparatus requires very long forming lines with a multiplicity of sets of forming rollers and as such have been somewhat impractical.
To address these problems the present inventor has previously proposed in Australian Patent application no. 48883/90 a method of erecting such buildings and apparatus for forming building elements of the above kind. Although the proposal goes a long way towards providing an effective and efficient solution to these problems it has been found that the proposed apparatus does not have sufficient operational flexibility to provide for building spans exceeding 20 meters. Additionally said apparatus is not sufficiently operationally flexible to provide adjustment of radius of curvature of the elements during operation and/or without considerable rearrangement and realignment of equipment and time loss.
An object of the present invention is to provide a process and apparatus which addresses one or more problems and deficiencies identified above or later in the specification.
SUMMARY OF THE INVENTION
The present invention provides apparatus for forming an elongate longitudinally arcuate building element of channel cross-section having transverse ribs from sheet metal comprising a set of coextensive generally in register dies through which a sheet of metal can be received, said set comprising a male die and a female die which cooperate to form transverse ribs in the sheet wherein further one of said male die and female die is provided with a concave leading edge and the other die is provided with a convex leading edge thereby the dies cooperate to plastically deform the sheet into a channel section.
It is preferred that the male die is provided with an upright protrusion projecting from its leading edge and extends along at least part of its length.
It is also preferred that the female die is provided with a coextensive recess extending along at least part of its length.
More preferably, both the protrusion and the recess extend a major portion of their respective edges.
It is preferred that the leading edges remain in register during operation of the apparatus.
Preferably the dies are provided with orbital motions which cooperate to bring the dies into engagement with the sheet, draw the sheet along a transit path therebetween while cold-forming the sheet and then disengage the sheet with each sweep about their orbits.
It is preferred that the dies are provided with means to adjust the radius of curvature of either or both the respective concave leading edge or the convex leading edge.
Adjustment of the radius of curvature of a leading edge may, for example, be effected by means of providing a female die formed of a plurality of segments held side to side having a gap provided between at least a portion of each of the segments, the width of the gap being adjustable so as to effect adjustment of the radius of curvature of the leading edge.
In one embodiment the die is formed of two substantially identical half segments.
Preferably the half segments are hinged to one another towards their leading end.
It is also preferred that the said set of dies are mounted on crank mechanisms to provide the dies with said cooperating orbital motions. In embodiments of this kind the dies may engage respective opposite sides of the sheet as it travels along a transit path through the apparatus, plastically deform the engaged portions of the sheet to form transverse ribs and advance with the sheet as deformation occurs, then release the sheet as it advances further along its transit path. Simultaneously the dies plastically deform the sheet into channel section by virtue of their respective concave and convex leading edges. This step may be repeated for each rib.
It has been found that the radius of longitudinal curvature of the element is closely related to the number of ribs per unit length of the element and as such is a function of both the speed of orbital motion of the dies and the speed of the sheet advancing along its transit path. It has also been found that the depth of the ribs also influence said curvature. The present invention facilitates rapid presetting of the radius of longitudinal curvature of the element by simple presetting of orbital motion speed and die intrusion length, without the need to alter sheet advancement speed and enables adjustment of said radius during operation of the apparatus by simple adjustment of the speed of orbital motion of the dies.
It is preferred also that guide means is provided in advance of the dies to receive the strip from a coil in a substantially flat configuration and pass the strip to a arcuate nip formed by the leading edges of the dies in a shape in cross-section corresponding generally to the shape in cross-section of the arcuate nip without plastically deforming the strip into said shape.
It is also preferred that drive means in the form of, for example, drive rollers is provided in advance of the guide means to drive the sheet in the form of strip from the coil to the dies through the guide means.
It is preferred that the apparatus further comprises edge flange forming means to operate on each longitudinal edge of the sheet.
More preferably the edge flange forming means comprise at least two pairs of cooperating edge forming rollers with each pair of rollers operating on a respective longitudinal edge to form flanged edges.
The flanged edges of each sheet may be formed as respective male and female formations so that two elements disposed side by side with overlapped flanged edges enable the male formation of one element to nestle in the female formation of the other element.
It is preferred that the sheets are provided from a coil of strip and that the apparatus further comprises shears to cut said strip into sheets of predetermined length. The shears may be disposed in advance of the forming dies so that discrete sheets pass through the forming dies or more preferably downstream thereof so that the cold-formed strip is cut into cold-formed elements.
Ausarch Pty. Ltd.
Crane Daniel C.
Larson & Taylor PLC
LandOfFree
Cold-forming process and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cold-forming process and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cold-forming process and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2523975