Apparatus for roll forming purlins and the like from a metal...

Details Apparatus for roll forming purlins and the like from a metal... Apparatus for roll forming purlins and the like from a metal...

2000-01-07

2001-09-18

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...

C072S181000

Reexamination Certificate

active

06289708

ABSTRACT:

TECHNICAL FIELD
The present invention relates to an apparatus for roll forming purlins and the like from a metal strip. The invention can be implemented in the forming of purlin profiles of various sizes and material thicknesses in the same roll forming machine.
In purlins and similar products used in construction and industry, bendings are usually 90° basic bendings, but other bending angles are also applicable. Purlins with a U, C or Z profile are commonly used as steel construction elements.
BACKGROUND ART
Prior art will be described below with reference to the accompanying drawings, in which:
FIG. 1
is a top plan view of a conventional prior-art apparatus for roll forming purlins from a metal strip,
FIG. 2
is a side view of a part of a prior-art roll forming apparatus,
FIG. 3
is a cross-section of a purlin formed in the prior-art roll forming apparatus of
FIG. 2
,
FIG. 4
shows how C or U purlins are being formed in a prior-art arrangement, and
FIG. 5
shows how Z purlins are being formed in the prior-art arrangement of FIG.
4
.
FIG. 1
illustrates a known apparatus for roll forming purlins from a metal strip
1
of thin metal sheet. The metal strip
1
enters the roll former from the left (arrow A), and a purlin
1
′ formed from the strip
1
leaves the roll former to the right. The forming of the strip
1
in the roll former is illustrated by three cross-sections marked with braces in FIG.
1
. In this case, the roll former comprises two sets of rollers, the first set
2
bending the two outermost edges of the purlin
1
′ to 90° (=the outermost corners inwards by 90°).
After this, the second set of rollers
3
of the roll former bends the innermost sides of the purlin
1
′ to 90° (=the innermost corners inwards by 90°). The finished U or C profiled purlin
1
′ will leave the roll former to the right.
FIG. 2
shows the design of sets of freely rotatable or idling rollers in a prior-art roll former, and
FIG. 3
shows the cross-section of the purlin
1
′. In
FIG. 2
, the set of rollers of the roll former comprises rollers
5
-
12
rotatably mounted on a frame
4
. The operation of the roll former is based on the fact that, as the horizontal and schematically shown metal strip
1
is fed into the set of rollers
5
-
12
from the left, it will first reach the roller
5
, which makes the first bending of the strip
1
. Subsequently, the strip
1
reaches the following roller
6
, which in turn bends the strip
1
slightly more. Each following roller
7
-
11
in the set of rollers will bend the strip
1
slightly more, until the final roller
12
bends the strip
1
in a desired final 90° angle (cf. FIG.
3
).
There are a number of previously known roll forming machines for manufacturing U or C purlins. There are also various known roll forming machines for Z purlins. In this case, the bendings in the roll forming line must be feasible not only upwards but also downwards.
FIGS. 9A-9E
of U.S. Pat. No. 4,716,754 to Youngs, for instance, illustrate a known solution for forming Z purlins. As to the background art, U.S. Pat. No. 4,787,232 to Hayes should also be mentioned, which discloses a roll former for the manufacture of purlins of various profiles.
The degree of difficulty is increased by the fact that U, C and also Z purlins need to be manufactured in the same roll forming line. Commonly available solutions to this problem have been based on changing of the individual rollers or frame members, such as rafts or cassettes, on which the sets of rollers are already mounted. Such changes are laborious and require skilful operators, and special lifting equipment is needed.
FIG. 4
shows a prior-art roll forming arrangement as C or U purlins are being formed. This known arrangement comprises a left-hand and a right-hand roll forming block
13
,
17
, respectively, drive rollers
14
,
18
and sets of rotatable rollers
15
,
16
,
19
. The illustrated prior-art solution can be used to form the metal strip
20
into C or U purlins in the normal state.
FIG. 5
illustrates the prior-art roll forming arrangement of
FIG. 4
as Z purlins are being formed. When Z purlins are being formed, the left-hand roll forming block
13
has been lifted vertically upwards (arrow B) relative to the right-hand roll forming block
17
which normally is stationary. The metal strip
21
to be formed will now be differently positioned relative to the drive rollers
14
,
18
and to the rotatable rollers
15
,
19
. In addition, lifting the entire forming block
17
will require separate, complex and heavy-duty lifting equipment. The illustrated prior-art solution will form Z purlins in this state.
The prior-art solution illustrated in
FIGS. 4-5
has the drawback of a complex design, involving up to three shafts. On top of that, the lifting of the entire forming block
13
is extremely awkward.
The arrangement shown in
FIGS. 4-5
is described in an article by Karl D. Forth entitled “Split-level roll former speeds changeover” issued in February 1996. These known roll formers are marketed by the US company Bradbury Co.
In a further known solution, the pair of rollers turns 180° about its forming centre. The rotating shafts require high accuracy of manufacture and advanced equipment, by means of which the rotation is controlled and blocked (cf. U.S. Pat. No. 4,787,232 to Hayes).
SUMMARY OF THE INVENTION
The purpose of the present invention is to provide an improved apparatus for roll forming purlins or the like from a metal strip, which enables the problems above to be resolved and the drawbacks to be eliminated. This is achieved by an apparatus according to the invention, which has the features of appended claim
1
, preferred embodiments being defined in the subclaims.
The improved apparatus of the invention has several advantages. Thanks to the new and unique arrangement of the rollers, and the structure and adjustment of the same, a very effective manufacture of purlins can be accomplished. The movement of the strip bending rollers is achieved in a simple but ingenious way.
The roll forming apparatus of the invention has the advantage of being operational and of having a straight-forward design. In addition, by the invention, the bending is performed with such rollers that tend to reduce friction during forming. The invention involves simple adjustment of the material thickness both in the horizontal and in the vertical direction.
In accordance with the invention, roll forming and prepunching of purlins can take place in the same integrated line, and bendings of various sizes and in various directions (upwards and downwards bending) are automatically performed.
A preferred embodiment involves the further advantage of performing the forming with idle rollers, so that there will not be high friction caused by difference of speed against the metal strip to be formed.


REFERENCES:
patent: 2458906 (1949-01-01), Himmel et al.
patent: 2471490 (1949-05-01), Mercer
patent: 3462989 (1969-08-01), Fischer, Jr.
patent: 3914971 (1975-10-01), Colbath
patent: 4716754 (1988-01-01), Youngs
patent: 4787232 (1988-11-01), Hayes
patent: 5829294 (1998-11-01), Bradbury
patent: 5983691 (1999-11-01), Voth et al.
patent: 6148654 (2000-11-01), Jensen et al.
patent: 6216514 (2001-04-01), Bradbury
patent: B-71186/87 (1987-10-01), None
patent: 1022072A2 (2000-01-01), None
patent: 2188859A (1987-10-01), None
Rollforming and associated machinery for the Metal Building Components Manufacturing Industry. Datasheets [online]. Hayes International, 19??, [retrieved on Sep. 22, 1997] Retrieved from the Internet: URL=“http://www.HAYESINT.COM.AU” URL=“http://www.HAYESINT.COM.AU/AboutHayes.html” URL=“http://www.HAYESINT.COM.AU/Products.html” URL=“http://www.HAYESINT.COM.AU/WhatsNew.html”.
The Automated Purlin Rollformer.
Forth, Feb. 1996, Modern Metals, Split-level Roll Former Speeds Changeover, (Reprint).

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