Metal deforming – By pulling workpiece through closed periphery die – Utilizing specified work moving means
Reexamination Certificate
2002-05-09
2004-02-10
Tolan, Ed (Department: 3725)
Metal deforming
By pulling workpiece through closed periphery die
Utilizing specified work moving means
C072S278000, C072S290000, C072S430000, C072S442000
Reexamination Certificate
active
06688152
ABSTRACT:
FIELD OF THE INVENTION
Our present invention relates to a drawing device for the drawing of elongated material, especially with cross section reduction in a drawing stage of a drawing line. More specifically, the invention relates to the drawing of elongated metal workpieces from billets or bars utilizing a drawing device having at least one drawing carriage, a drive for the carriage and, if appropriate, a drawing die for shaping and reducing the cross section of the workpiece.
BACKGROUND OF THE INVENTION
Drawing machines are used for the drawing of elongated metal workpieces like tubes, bars or rods, through a tool or die with reduction in cross section at the tool and, if desired, shaping of the workpiece to a particular profile. The workpieces can be referred to as structural shapes or as profiles. Drawing machines of the type described can be so-called continuous drawing machines in which the length of the workpiece can be many times greater than the length of the machine and the workpiece can emerge more or less continuously. Drawing machines can also be discontinuous drawing machines capable of drawing a workpiece of only a limited length and sometimes referred to as drawing benches.
One example of a continuously working linear drawing machine is found in DE 28 52 071. This patent document discloses a carriage-type drawing machine in which two drawing slides or carriages are moveable parallel to the drawing direction along a guide on a machine frame. These carriages are movable back and forth and are provided with means for engaging the workpiece in a hand-to-hand mode so as to pull the workpiece more or less continuously through the die. The hand-to-hand machine is generated by double-arm levers which are connected to the slides or carriages and themselves are controlled by a double-curve cam which produces the back and forth motion of each carriage.
Another driving system for a drawing machine is disclosed in European patent document EP 0 371 165 which provides a rotating drum which has a cam formation in the form of a rib of its periphery to produce the opposite movements of the drawing slides or carriages. The short strokes of the curves means that each stroke will consist basically and predominantly of an acceleration segment and a braking segment. To ensure operation with a high mean drawing speed, a very high stroke frequency should be used. The stroke frequency, however, cannot be increased without limits since it is restricted by the fact that there is significant inertia at the reversal points.
In drawing processes which involve a plurality of drawing machines in succession and reduce the cross section of a workpiece in a number of stages, it is customary to reel up the driven product at the end of the drawing line. For this purpose, the drawing machines must be coupled together (see European patent document EP 0 182 922 A1). This can be achieved with a buffering of the length of the workpiece between drawing stages, e.g. by deflecting the workpiece out of its linear lie between the output side of one machine and the input side of the next machine.
When two or more such drawing machines are used together with loop-type buffering of the length of the workpiece, it is necessary in prior art systems to impart a bend to the workpiece which may impose requirements on the further processing. This applies also to systems in which the workpiece may be reeled or wound up between stages.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to provide a drawing machine, device or unit which is simple and thus of low capital cost, can be used effectively in drawing lines having multiple units and can have a high production rate with minimum operating and capital cost.
Another object of this invention is to provide an apparatus for drawing an elongated workpiece which represents an advance over the prior art systems described.
Another object of this invention is to provide a drawing apparatus which is free from drawbacks of prior art systems including those mentioned earlier.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter are achieved in accordance with the invention in a modular drawing apparatus for drawing an elongated workpiece, especially a metal workpiece, which comprises:
at least one elongated path-forming module alignable contiguously and directly with others of the path-forming modules to define an uninterrupted elongated travel path;
at least one holder module engaged with the at least one elongated path-forming module and constructed and arranged for selective attachment to the others of the path-forming modules;
a drawing die mounted in the at least one holder module; and
a drawing carriage provided with a device engageable with the workpiece and a part carrying the device and displaceable along the path relative to the at least one elongated path-forming module, the part and the path-forming module forming mutually interactive elements of a linear motor for direct displacement of the carriage along the path.
The drawing line embodying the invention can comprise two drawing apparatuses as described in respective drawing stages and located directly abutting one another contiguously along an aforementioned path.
According to the invention the drawing unit or puller for the workpiece is assembled in a modular manner from a plurality of modules which can be identical to one another and utilized interchangeably. These modules include at least one path-forming module which can be joined directly to at least one other path-forming module to form a continuous linear path along the drawing line. The term “directly connectable” is here used to signify that the path-forming modules adjoin one another in a direct end-to-end relationship without any intervening elements and are coupled together so as to be contiguous in their adjoining regions.
The apparatus includes at least one holder module for fastening a drawing die to the drawing unit. The holder module, which can be used interchangeably with other holder modules and can receive any of a number of dies which may be used in succession along the line, has formations which are complementary to those of each path-forming module so that any one of the path-forming modules may receive such a holder module, preferably at an upstream end thereof with respect to the drawing direction. According to the invention the drive means for the drawing carriage is a linear motor with the part carrying the workpiece clamp to the drawing carriage and the path-forming module constituting mutually interactive elements of the linear motor which directly displaces the carriage along the path.
The linear motor referred to herein is an inductive electrical linear motor of the type in which one of the elements forms the so-called stator and which is relatively stationary while the other element forms the armature and is linearly-shiftable by the inductive forces which are generated.
The coils for producing the electromotor force can be provided on one of the elements and the magnetic fields coil can produce eddy currents in the other element so that the magnetic field thereby induced can react with the electromagnetic field to provide the linear force along the path displacing the carriage to draw the workpiece through the die.
Since the drawing unit of the invention is itself of modular construction and is comprised of individual path-forming modules which can be joined together to form the path and in its simplest form has only one such path-forming module, each path-forming module can have a holder module for receiving a respective die. The holder module can be removed from the path-forming module and inserted interchangeably into a path-forming module further downstream. In addition the die may be removably mounted in the holder module. The result is a construction in which holder modules may be provided anywhere along the path and the retaining formations for the holder module can be located at various locations along each path-forming module so as to provide a d
Häusler Karl-Heinz
Klingen Hermann-Josef
Zillekens Norbert
Dubno Herbert
SMS Meer GmbH
Tolan Ed
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